U.S. patent application number 13/687404 was filed with the patent office on 2013-06-20 for solar cell combination.
This patent application is currently assigned to SolarWorld Innovations GmbH. The applicant listed for this patent is SolarWorld Innovations GmbH. Invention is credited to Wolfgang Enger, Matthias Georgi, Paul Grunow, Martin Kutzer, Holger Neuhaus, Thilo Richter, Matthias Schaarschmidt, Thomas Seidel, Olaf Storbeck.
Application Number | 20130152994 13/687404 |
Document ID | / |
Family ID | 43607360 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130152994 |
Kind Code |
A1 |
Schaarschmidt; Matthias ; et
al. |
June 20, 2013 |
Solar Cell Combination
Abstract
A solar cell combination having at least two independent
electrodes, in which at least one first electrode is formed by at
least one first wire conductor that first spans a plurality of
solar cells, and in which the first and the second electrodes are
contacted with each other, and the first and/or second electrode is
disconnected at the positions required for the connection.
Inventors: |
Schaarschmidt; Matthias;
(Limbach-Oberfrohna, DE) ; Richter; Thilo;
(Limbach-Oberfrohna, DE) ; Enger; Wolfgang;
(Chemnitz, DE) ; Seidel; Thomas; (Hartmannsdorf,
DE) ; Grunow; Paul; (Berlin, DE) ; Kutzer;
Martin; (Penig, DE) ; Storbeck; Olaf;
(Dresden, DE) ; Neuhaus; Holger; (Freiberg,
DE) ; Georgi; Matthias; (Dresden, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SolarWorld Innovations GmbH; |
Freiberg |
|
DE |
|
|
Assignee: |
SolarWorld Innovations GmbH
Freiberg
DE
|
Family ID: |
43607360 |
Appl. No.: |
13/687404 |
Filed: |
November 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/DE2010/075044 |
May 28, 2010 |
|
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13687404 |
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Current U.S.
Class: |
136/244 |
Current CPC
Class: |
H01L 31/0508 20130101;
H01L 31/18 20130101; Y02E 10/50 20130101 |
Class at
Publication: |
136/244 |
International
Class: |
H01L 31/05 20060101
H01L031/05 |
Claims
1. A solar cell combination in which the solar cells are contacted
with each other by at least two independent electrodes, wherein at
least one first electrode is formed from at least one first wire
conductor that first spans a plurality of solar cells, and wherein
the first and the second electrodes are contacted with each other,
and the first and/or the second electrodes are separated at the
positions required for the connection.
2. The solar cell combination according to claim 1, wherein at
least one first electrode is formed from at least one first wire
conductor, and the first electrode is contacted with the second
electrode between two solar cells.
3. The solar cell combination according to claim 1, wherein the
first electrode and/or the second electrode is separated between
the solar cells.
4. The solar cell combination according to claim 3, wherein between
two solar cells, a separating line between first and second
electrodes alternates with a contacting between first and second
electrodes.
5. The solar cell combination according to claim 1, wherein the
electrodes are connected/contacted with each other through contact
elements/cross-connectors.
6. The solar cell combination in which a plurality of solar cells
are contacted with each other by at least two independent
electrodes, wherein at least one first electrode is formed from at
least one first wire conductor that first spans a plurality of
solar cells, and wherein the first and the second electrodes are
contacted with each other, and wherein the solar cell combination
comprises: a first electrode on the light incidence side of a first
solar cell, wherein the first electrode consists of a multiplicity
of first wire conductors which are substantially parallel to each
other and which are contacted with the light incidence side of this
solar cell, a second electrode on the back side of an adjacent
second solar cell which is connected to the back side of said
second solar cell and which is contacted in the spacing toward the
first solar cell with the first electrode of the first solar
cell.
7. The solar cell combination according to claim 6, wherein said
solar cell combination comprises a plurality of solar cells which
are connected and contacted with each other, wherein the solar
cells are connected and contacted with at least one first wire
conductor of the first electrode, which first wire conductor runs
continuously in the longitudinal direction of successively arranged
solar cells, or the solar cells are connected and contacted with a
group of first wire conductors of the first electrode, and are
connected and contacted with at least one further contact element
or a group of contact elements so as to form together a solar cell
combination, and before or after establishing the electrical
connection, the first wire conductors and/or the further contact
elements are separated between the solar cells in such a manner
that a series connection or parallel connection is present.
8. The solar cell combination according to claim 7, wherein a
plurality of stripe-like solar cell combinations which are formed
by separating are connected and contacted again with each other in
such a manner that each first wire conductor runs from the upper
side of a solar cell to the lower side of the adjacent solar cell,
and the further contact elements are configured in the form of
cross-connectors which are arranged between the lower side of the
solar cell and the first wire conductor and are contacted with the
solar cells and the first wire conductors.
9. The solar cell combination according to claim 8, wherein each
first wire conductor is contacted on the upper side of a solar cell
and that the further contact elements are configured in the form of
second wire conductors and in the form of cross-connectors, wherein
the second wire conductors are contacted on the lower side of the
solar cells substantially parallel to the first wire conductors,
and at least one cross-connector which is contacted in series
connection with the first and second wire conductors extends
transverse to the first and second wire conductors.
10. The solar cell combination according to claim 6, wherein first
and second wire conductors alternate transverse to the longitudinal
direction.
11. The solar cell combination according to claim 6, wherein the
first wire conductors and/or the second wire conductors and/or the
cross connectors are configured in the form of a wire having a
substantially round or rectangular cross-section.
12. The solar cell combination according to claim 6, wherein the
ends of the first and/or second wire conductors and/or the ends of
the cross-connectors are provided with electrical collecting
connectors.
13. The solar cell combination according to claim 6, wherein the
first and/or the second wire conductors and/or the cross-connectors
are firmly bonded with the solar cells.
14. The solar cell combination according to claim 6, wherein the
first and/or second wire conductors and/or the cross-connectors are
directly connected to the solar cells without the need of printed
bars or strip connectors thereon.
15. The solar cell combination according to claim 6, wherein the
wire conductors are comprised of metal and are coated for
establishing the connection to the solar cells or to each
other.
16. The solar cell combination according to claim 6, wherein
different joining technologies are implemented on front and back
sides.
17. The solar cell combination in which the solar cells are
contacted with each other by at least two independent electrodes,
wherein at least one first electrode is formed from at least one
first wire conductor that first spans a plurality of solar cells,
and wherein the first and the second electrodes are contacted with
each other, and the first and/or the second electrodes are
separated at the positions required for the connection and that
transverse to the first and second wire conductors at least one
cross-connector extends which is contacted with the first and
second wire conductors, wherein the contact elements and/or the
cross-connectors are structured in such a manner that in the solar
module, the light reflected by said contact
elements/cross-connectors is directed through total internal
reflection on the glass to the active cell surface.
18. The solar cell combination according to claim 17, wherein the
contact elements are coated in such a manner that they have a
diffusely reflecting surface.
19. The solar cell combination in which the solar cells are
contacted with each other by at least two independent electrodes,
wherein at least one first electrode is formed from at least one
first wire conductor that first spans a plurality of solar cells,
and wherein the first and the second electrodes are contacted with
each other, and the first and/or the second electrodes are
separated at the positions required for the connection, and wherein
separated solar cells are contacted and connected with each
other.
20. The solar cell combination according to claim 19, wherein the
second electrode is configured in the form of at least one metal
band or metal film.
21. The solar cell combination according to according to claim 19,
wherein the metal band and/or the metal film has a reinforced edge
region for contacting with the first electrode of the adjacent
solar cell, wherein the reinforced edge region acts as a contact
element or as a replacement for a contact element.
22. The solar cell combination according to claim 19, wherein the
second electrode is formed from a multiplicity of second wire
conductors which are substantially parallel to each other.
23. The solar cell combination according to claim 19, wherein the
contact element/the cross-connector, which is arranged between two
solar cells, has substantially the same thickness or a greater
thickness than the solar cells.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a solar cell combination, wherein
contacting the solar cells is carried out through wire conductors,
and a plurality of solar cells are combined with each other through
the wire conductors so as to form the solar cell combination.
[0002] A solar cell usually consists of a substrate having a front
side and a back side, wherein a contact structure is applied onto
at least one of the two sides. Typically, the contact structure has
a width of at least 100 .mu.m, whereas its thickness is only
approximately 10 to 15 .mu.m. A larger width causes a decrease of
efficiency due to the resulting increased shading, whereas reducing
the width results in the disadvantage that the line resistance of
the contact structure is increased. Furthermore, the current of the
individual contact structures is fed into busbars causing further
shading on the front side surface.
[0003] On the back side of the solar cell there is usually a
large-area contact structure that collects the current
extensively.
[0004] Connecting solar cells is generally carried out through
contact ribbons that are soldered onto the busbars of the solar
cell. All the current is fed through the contact ribbons. In order
to keep the resistance losses as low as possible, a certain total
cross-sectional area of these ribbons is required. The result of
this is that there is a loss on the front side caused by the
shading.
[0005] In order to create an optimal solar module it is therefore
necessary that the contact structure of the solar cell and the
number and dimensions of the contact ribbons are optimized in
combination with each other.
[0006] A problem here is the handling and positioning of the thin
wires on the solar cell. In particular the series connection of the
cells causes problems since--analogous to the solder ribbons of the
standard soldering process--the wires have to be brought from the
front side of the first solar cell to the back side of the second
solar cell. This implies also that for contacting front and back
sides, the same material has to be used.
[0007] From DE 298 05 805 U1, a device for processing solar cells
is known, wherein individual solar cells are interconnected with
electrical connectors so as to form a string. For this purpose, the
device comprises a connection strip receptacle, a soldering paste
dispenser that applies the soldering paste onto the connection
strips, at least one solar cell depositing rack as a soldering
station, one turning device for the connection strips and one
transport device from the turning device to the solar cell
depositing station for depositing the connection strips onto the
solar cells.
[0008] The disadvantage of this solution is that only connectors in
the form of strips can be used which, moreover, have to be turned
over. A solar cell comprising at least one semiconductor layer
arranged on a metallic carrier and a multiplicity of contact paths
arranged on the semiconductor layer is described in DE 10 2006 041
046 A1. A lateral protrusion of at least one contact path is bent
onto a back side of the carrier and is arranged electrically
insulated with respect to the carrier. Solar cells arranged next to
each other are preferably connected to each other through strip
conductors having a perforated configuration so as to enable local
contacts by soldering through. This construction of the solar cell,
carrying out the method for producing the solar cell, and the
constructional implementation of the strip conductor shall enable
to interconnect individual solar cells so as to form solar modules
and to interconnect the individual solar cells as desired. The
carrier is formed here as a metal band, wherein the contact paths
are arranged transverse to or along a longitudinal direction of the
carrier, protrude laterally beyond the carrier band, and can be
used in this manner for interconnecting. Furthermore, collecting
paths are arranged transverse to the longitudinal direction and
transverse to the contact paths and are electrically connected to
the contact paths, and the contact paths as well as the collecting
paths are glued in the region of the back side of the carrier. The
contact paths or collecting paths are implemented in the form of
copper wire or copper band. In order to avoid an electrical
connection between the contact path and the metallic carrier,
insulations implemented as edge insulations are arranged along the
edge. Overall, structuring and connecting individual solar cells by
using perforated strip conductors is problematic, and using edge
insulations involves increased manufacturing-related expenses.
[0009] A wire system for electrically contacting a solar cell,
comprising a wire conductor that runs alternately between a first
contacting section and a second contacting section arranged spaced
apart from the first contacting section in such a manner that the
wire conductor forms the wire system with a mesh-like arrangement
which extends with a multitude of meshes along an extension
direction, is known from DE 10 2007 022 877 A1. The wire conductor
is fixed in the mesh-like arrangement through fixing means provided
in addition to the wire conductor, and/or through fixing means in
the form of sections of the wire conductor, which section are wound
around each other. The wire conductor runs as an endless string
periodically alternating back and forth along an extension
direction between a first contacting section and a second
contacting section. The two contacting sections are regions of the
wire system, which regions are equidistantly spaced apart from each
other and run along the extension direction of the wire system. In
each case two solar cells arranged next to each other have solar
cell contacting sections which are arranged opposing each other in
the adjoining edge regions of the solar cells and which are
connected to each other through the mesh-like wire conductor.
Furthermore, an electrically insulating base insulator layer is
provided in the solar cell contacting section of a solar cell, and
an electrically insulating emitter insulator layer is provided in
the adjacent solar cell so that a series connection is generated.
Producing the mesh-like wire conductor is relatively complicated. A
significant disadvantage of this solution is also that the
efficiency is negatively influenced because the areas for
contacting between front side and back side are required in two
dimensions.
[0010] The strings produced as a pre-stage for the assembly of
modules have the disadvantage that the cells are put on
individually and are covered with tin-plated copper band pieces
which cover the cells and also extend below the next cell to be put
on. These copper bands are soldered with different processes. This
method requires preparation of the cells with a print image as
solder connection material and as strip conductor for "collecting"
the free electrons and transporting to the copper bands.
[0011] The strings are picked up by handling devices, aligned and
assembled so as to form modules. The assembled strings are
electrically connected through cross-connectors so as to form a
module. The required connections are produced successively in
individual process steps resulting in long production times.
[0012] From DE 102 39 845 C1, an electrode for contacting an
electrically conductive surface, in particular at least one surface
of a photovoltaic element, is known. Said surface consists of an
electrically insulating, optically transparent film, an adhesive
layer applied onto a surface of said film, and a first group of
substantially parallel, electrically conductive wires which are
embedded in the adhesive layer, protrude with a portion of their
surface from the adhesive layer, and, at least on the surface
protruding from the adhesive layer, are coated with a layer having
a low melting point, wherein the wires of the first group are
electrically connected to a first contact strip.
[0013] A second group with wires running substantially parallel to
each other is arranged between the transparent film and the wires
of the first group, wherein the wires of the first and second
groups together form a grid, and wherein the wires of the second
group are electrically connected to a second contact strip. Due to
the use of the film and the adhesive, this constructional
configuration is very complicated. In the case of an irregular
thickness of the adhesive layer, the wires protrude irregularly
from said adhesive layer or can also be completely covered by the
adhesive, which can result in defects. Furthermore, the film and
the adhesive remain in the module; this implies relatively high
demands in terms of long-term stability to be met by the adhesive
and the film and therefore causes relatively high costs. Moreover,
the prefabrication of electrodes from wire, optically transparent
film and adhesive is technologically sophisticated.
[0014] A method for interconnecting solar cells by using
prefabricated metal mesh (e.g. aluminum gage) which is contacted
with the surface of the cell on the front side and the back side is
known from JP 59115576 A. Under the influence of pressure and
temperature, the metal mesh is connected in each case to one cell
by means of a heating unit. In the case of this solution, handling
is relatively complicated.
[0015] In EP 0 440 869 A1, a component is described which comprises
a photosensitive semiconductor plate having a barrier structure,
electrically conductive current collector contacts arranged on both
sides of the semiconductor plate, and protective coatings and
current dissipating electrodes arranged on both sides of the
semiconductor plate. At least the electrically conductive current
collector contacts arranged on the front side of the semiconductor
plate are implemented in the form of electrically connected and
successive sections which are in contact or not in contact with the
surface of the semiconductor plate. For this purpose, the current
collector contacts are made from a bent wire. This embodiment is
very complicated and it can easily occur that the thin bent wire
gets crushed.
[0016] Furthermore, all known assembly technologies for solar
modules have reached their limits with regard to their possible
cycle time and the processing of thin cell materials, which is
counteracted through stringing together a plurality of machines. In
general, this has a negative effect on the production costs.
[0017] Moreover, the connection materials cover an undesirably
large portion of the usable silicon surface and thus deteriorate
the efficiency of the solar cell.
[0018] Furthermore, it is common to apply special metal pastes
(mostly silver or silver alloys) in the form of strip conductors
onto the solar cells (so-called bars), e.g., by using the screen
printing method, in order to ensure contacting with the wire
conductors. This makes the solar cells even more expensive.
SUMMARY OF THE INVENTION
[0019] It is an object of the invention to provide a solar cell
combination, wherein costs are minimized and the efficiency of the
solar cells is improved.
[0020] Another object of the invention is to reduce the printed
regions for the bars or strip conductors or to eliminate them
completely.
[0021] These and other objects are achieved with the features of
the invention as described and claimed hereinafter.
[0022] The method for contacting and connecting solar cells for
producing the solar cell combination according to the invention is
carried out by means of at least two independent electrodes,
wherein at least one electrode is formed from at least one or a
plurality of wire conductors that are substantially parallel to
each other, and after the contacting between solar cells and
electrodes, establishing a series connection or parallel connection
takes place by separating the wire conductors required for this at
the required positions and by establishing the connection between
the electrodes, wherein establishing the connection between the
electrodes is implemented before or after separating.
[0023] It is therefore possible to connect or contact the
electrodes with each other directly or through contact
elements/cross-connectors before or after separating.
[0024] According to the method, contacting and connecting solar
cells by means of wire conductors so as to form a solar cell
combination is carried out, for example, in that in a manner as
continuous as possible, a plurality of solar cells [0025] are
connected to at least one first wire conductor that runs preferably
continuously and linearly in the longitudinal direction of
successively arranged solar cells, or are connected to a group of
preferably continuously running first wire conductors [0026] and
[0027] to at least one preferably continuously running further
contact element or a group of preferably continuously running
further contact elements so as to form together a solar cell
combination, and [0028] an electrical connection is established
between the first wire conductors, the further contact elements and
the solar cells of the solar cell combination, and [0029] if
required, the first wire conductors and/or the second contact
elements can be separated before or after establishing the
electrical connection in such a manner that a series connection or
parallel connection of the solar cells is created or can be
established.
[0030] By using in particular continuous first wire conductors and
further (in particular continuous) contact elements which extend
linearly in the assembly direction, and/or transverse to the
assembly direction, extend also linearly and are optionally
separated, the production of solar cell combinations is
revolutionized and thus is made significantly more effective and
more cost-efficient.
[0031] Preferably, the first wire conductors are contacted on the
upper side of the solar cells, wherein then the further contact
elements can be configured in the form of two electrical
cross-connectors which run transverse to the first wire conductors,
between adjacent solar cells, and are applied to the first wire
conductors and are connected to them. Subsequently, the first wire
conductors are separated transverse to their longitudinal extension
and parallel to the electrical cross-connectors between adjacent
solar cells so that a stripe-like combination of solar cells with a
protruding region of first contact elements and with the two
cross-connectors is generated. This region is connected to the
lower side of the adjacent solar cells so that at least one
cross-connector is provided on the lower side of the adjacent solar
cells and is now contacted with them.
[0032] As an alternative, it is also possible to fasten and contact
preferably a multiplicity of first wire conductors on the upper
side of solar cells arranged next to each other and to fasten and
contact the cross-connectors on the lower side of the solar cells,
wherein the cross-connectors and the first wire conductors likewise
run perpendicular to each other. Subsequently, the first wire
conductors are separated, transverse to their longitudinal
extension and parallel to the cross-connectors, between adjacent
solar cell(s) so that a stripe of solar cells is generated, which
solar cells are connected to each other through the two
cross-connectors, and which stripe has a protruding region with
first wire conductors. Subsequently, the region of the first wire
conductors protruding beyond the solar cell(s) is contacted with
the cross-connectors on the lower side of adjacent solar cells.
[0033] Another method variant for producing the solar cell
combination is that the first linearly running wire conductors are
also contacted on the upper side of, in particular, a plurality of
solar cells and that further contact elements are configured in the
form of second wire conductors and also in the form of
cross-connectors, wherein the second wire conductors run in
particular linearly and are contacted on the lower side of the
solar cells substantially parallel to the first wire conductors.
The first and the second wire conductors are connected to each
other through the electrical cross-connectors, wherein the
cross-connectors preferably run between the first and second wire
conductors.
[0034] Subsequently, the connections of the first wire conductor
and the second wire conductor to the cross-connector are in each
case alternately disconnected so that a series connection is
created.
[0035] In a third production variant, the preferably continuous
first wire conductor(s) runs (run) alternately between the upper
side and the lower side of adjacent solar cells. The second contact
elements are preferably configured in the form of continuously
running second wire conductors which run substantially parallel to
the first wire conductors, wherein the second wire conductors run
alternately (opposite) to the first wire conductor(s) between the
lower side and the upper side of adjacent solar cells.
Subsequently, the first wire conductors and the second wire
conductors are preferably alternately disconnected between the
solar cells in such a manner that likewise a series connection is
created.
[0036] Disconnecting the first and/or the second wire conductor is
carried out mechanically or preferably by means of laser.
[0037] In particular, successively arranged solar cells are
connected to each other by a multiplicity of first wire conductors
and/or second wire conductors and/or cross-connectors, which are
arranged next to each other with regard to the longitudinal
direction so that from the first wire conductors and/or the second
wire conductors and/or cross-connectors in connection with the
solar cells a kind of fabric is generated.
[0038] Preferably, the ends of the first and/or second wire
conductors and/or cross-connectors are provided with electrical
collecting connectors for current collection. After the first and
second wire conductors or the cross-connectors have been applied to
the solar cells, establishing the contacting (electrical
connection) is carried out by means of conventional bonding
technologies, e.g., by glueing, soldering or welding.
[0039] In this connection it is possible for the first time that
establishing the contacting between the wire conductors or the
cross-connectors and the solar cells is carried out while reducing
or eliminating the printing of bars onto the solar cell. Since the
bars consist in most cases of silver, this means a considerable
cost reduction for the solar cell combinations.
[0040] The solar cell combination is preferably produced such that
said solar cell combination is separated into a plurality of
strings or solar cell modules, or that it forms a solar cell
module. Thus, it is actually possible for the first time to produce
a large combined surface consisting of solar cells that are
connected and contacted with each other.
[0041] The solar cell combination according to the invention
comprises a plurality of solar cells that are connected and
contacted with each other, wherein the solar cells are connected
and contacted with at least one first wire conductor that runs
(continuously) in the longitudinal direction of successively
arranged solar cells, or are connected and contacted with a group
of first wire conductors, and are connected and contacted with at
least one further contact element or a group of further contact
elements so as to form together a solar cell combination, and
wherein before or after establishing the electrical connection, the
first wire conductors and/or the further contact elements are
separated (between the solar cells) such that preferably a series
connection is present.
[0042] In a first variant, a plurality of solar cell combinations
formed through separating can be connected and contacted again with
each other. For this, the first wire conductor(s) can in each case
run from the upper side of a solar cell to the lower side of the
adjacent solar cell. The further contact elements are then
configured in the form of cross-connectors which are arranged
between the lower side of the solar cell and the first wire
conductor and which are contacted with the solar cell(s) and the
first wire conductor(s).
[0043] In a second variant, a multiplicity of first wire conductors
that are parallel to each other are in each case also contacted on
the upper side of the solar cells. The further contact elements are
configured in the form of second wire conductors and in the form of
cross-connectors, wherein the second wire conductors are contacted
on the lower side of the solar cells substantially parallel to the
first wire conductors, and wherein transverse to the first and the
second wire conductors, at least one cross-connector extends which
is preferably contacted in series connection with said first and
second wire conductors.
[0044] For ensuring the series connection, the first and second
wire connectors are alternately disconnected from the
cross-connector. Furthermore, in this variant, the cross-connector
is preferably arranged between the first and second wire conductors
and thus is preferably arranged between two adjacent solar cells
and perpendicular to the first and second wire conductors.
[0045] This new contacting and connecting of solar cells by means
of two independent electrodes in the form of first and second wire
conductors, wherein at least one electrode consists of thin wires
that are parallel as far as possible, enables the production of a
new generation of solar cell modules.
[0046] A particular feature here is that different electrode
materials and joining technologies can be used for front and back
sides.
[0047] A wire field preferably consists in each case of 10-50
(optimal are approx. 20) wires in almost equidistant arrangement
and with a thickness of 50-300 .mu.m. The cross-section of the
wires of the first wire conductors (first electrode) and the
cross-section of the wires of the second wire conductor (second
electrode) can be different, e.g., round, oval, rectangular,
trapezoidal, etc. The wire conductors are made of metal, for
example, Cu, Al, Ni, steel, and can be coated, in particular for
establishing the connection to the solar cells or to each other,
for example, with solder (Sn--Pb, Sn--Pb--Ag, Sn--Bi, etc.), with
Ni, or also with an electrically conductive adhesive layer.
[0048] After generating an electrical contact between the first
electrode and the front side of the solar cell and also between the
second electrode and the back side of the solar cell, the
connection of the two electrodes is implemented. For generating the
electrical contact, known soldering, glueing or bonding techniques
can be used. A particular feature is that, for the first time,
different joining technologies can be used for the front and back
sides. For connecting the first electrode (first wire conductors)
and the second electrode (second wire conductors or bands),
preferably, the contact elements in the form of cross-connectors
running in the direction transverse to the wires are used. The
cross-connectors are electrically conductive and, for example, can
be made of metal or a metal compound. The connection between
electrodes (first and second wire conductors) and the contact
element/cross-connector can be implemented through a solder-,
crimp-, welded or glued connection.
[0049] The contact element/the cross-connector is preferably
arranged between the first and second (both electrodes) wire
conductors (in this case between adjacent solar cells) or above or
below both of them.
[0050] The contact elements/cross-connectors can be structured so
that later in the module, the light reflected by them is directed
through total internal reflection to the active cell surface.
[0051] Furthermore, coating the contact elements is conceivable
such that no reflective and shiny surface is generated, but a
diffusely reflecting surface is generated so that likewise a large
portion of the reflected light reaches the active cell surface with
the result that the efficiency can be further increased.
[0052] For producing such a solar cell combination, the first wire
conductors are arranged above the upper side of the solar cells and
the second wire conductors are arranged below the lower side of the
solar cells.
[0053] For this purpose, the second wire conductors are first
positioned on a support and subsequently, the solar cells and the
cross-connectors are placed thereon and thereafter, the first wire
conductors are deposited on the upper side of the solar cells. This
still "loose combination" is subsequently connected to each other
and contacted. In order to bring the up to now still
short-circuited cells into an electrically useful series connection
or parallel connection, it is now necessary to remove the
superfluous and disturbing wire bridges.
[0054] For this purpose, alternately, every second wire field in
the spaces between the cells is separated or cut out so as to
disconnect all connections with identical polarity within the
string.
[0055] Separating/cutting can be carried out, among other things,
by means of laser or, in particular, a self-centering cutting
device which exerts no forces during cutting on the wires so as to
avoid damage to the solar cells.
[0056] Here, it is possible to adjust the cutting device by means
of a camera system using the cell edges as a reference.
[0057] In a third variant of the solution according to the
invention, the first continuous wire conductor(s) runs (run)
alternately between the upper side and the lower side of adjacent
solar cells. The further contact element(s) is (are) configured in
the form of one or a plurality of second wire conductors which are
substantially parallel to the first wire conductors, wherein the
second wire conductor(s) runs (run) alternately opposite to the
first wire conductor(s) between the lower side and the upper side
of adjacent solar cells. Furthermore, the first and the second wire
conductors are preferably separated between the solar cells in such
a manner that a series connection is present. Preferably, a
multiplicity of first wire conductors and a multiplicity of further
contact elements are provided so that a kind of fabric is formed.
In this manner, in particular, a multiplicity of first wire
conductors are fed in each case over one solar cell, and by using
second wire conductors, a multiplicity of these second wire
conductors is also fed in each case over one solar cell, thereby
ensuring an optimal electron collection.
[0058] In the top view on the solar cell combination, the first and
second wire conductors are arranged alternately.
[0059] The first wire conductors and/or the second wire conductors
and/or the cross-connectors are preferably configured in the form
of a wire having a substantially round or rectangular
cross-section, or are configured in the form of a band and have in
particular only a very small cross-section. Said very small
cross-section is possible here if with one solar cell a plurality
of first and/or second wire conductors are contacted.
[0060] Furthermore, the ends of the first and/or second wire
conductors and/or the ends of the cross-connectors are provided
with electrical collecting connectors for tapping the current.
[0061] The first and/or the second wire conductors and/or the
cross-connectors are connected to the solar cells in particular in
a firmly bonded manner, e.g., by glueing, soldering or welding.
[0062] For the first time, it is also possible to connect the first
and/or second wire conductors and/or the cross-connectors directly
to the solar cells without the need of printing bars (strip
conductors) thereon.
[0063] Furthermore, it is possible to divide the solar cell
combination into segments by separating the wire conductors or
cross-connectors. These segments can be placed offset on top of
each other and can be connected so as to form a solar cell module
or a module combination.
[0064] However, the production can also be carried out in strings,
as previously done.
[0065] A significant advantage of the solution according to the
invention is the ability to standardize interconnections and matrix
layout by parallelizing and using suitably wider electrode fields
so that unnecessary cell and string handlings can be avoided.
[0066] With the solution according to the invention, production
costs and thus the costs for the solar cell modules can be
significantly reduced. Furthermore, it is possible to substantially
reduce the expenses for equipment or the facility costs, and to
reduce the floor space required for the production of solar cells.
Since it is possible to form a solar cell combination from a
multiplicity of solar cells in a largely continuous manner or in
one work step (in variant 2), the load acting on the cells due to
assembly stress decreases.
[0067] Another advantage of the solution according to the invention
is due to the fact that the use of expensive materials required for
printing the strip conductors can be significantly reduced, or it
is possible to completely eliminate the printing of strip
conductors since the wire conductors can be connected directly, in
particular soldered or glued, to the solar cells.
[0068] Furthermore, with the invention, the efficiency of the solar
cell modules can be considerably improved compared to conventional
solutions. This is in particular possible, when using a
multiplicity of wire conductors for each solar cell, through the
reduction of shaded surfaces and the increased reflection of the
lateral regions of the wires and also through lower internal losses
in the solar cell due to an almost full-surface electron
collection. Furthermore, it is possible to reduce efficiency losses
caused by cell breakage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] The invention is explained in more detail hereinafter by
illustrative embodiments shown in the accompanying drawings, in
which:
[0070] FIGS. 1 to 6 show the method steps for producing a first
variant of a solar cell combination from solar cells by using first
wire conductors and further contact elements in the form of
cross-connectors running transverse to said first wire conductors,
wherein
[0071] FIG. 1 shows a longitudinal section of solar cells arranged
one behind the other and next to each other, onto the upper side of
which first wire conductors have been placed, wherein between two
successively arranged solar cells, two cross-connectors are placed
over the first wire conductor,
[0072] FIG. 2 shows a three-dimensional view from above of a
partial area according to FIG. 1,
[0073] FIG. 3 shows a first row R1 of solar cells arranged next to
each other, which row has been formed by separating the first wire
conductors from the solar cells arranged upstream thereof,
[0074] FIG. 4 shows two rows R1, R2 of solar cells which are to be
connected to each other,
[0075] FIG. 5 shows a side view of rows R1 to R3 of solar cells,
which rows are contacted with each other,
[0076] FIG. 6 shows a three-dimensional view of a solar cell
combination produced according to variant 1,
[0077] FIGS. 7 to 10 show the method steps for producing a second
variant of a solar cell combination from solar cells by using first
wire conductors and further contact elements in the form of
cross-connectors running transverse to said first wire conductors,
and also second wire conductors which are parallel to the first
wire conductors and which run on the lower side of the solar cells,
wherein
[0078] FIG. 7 shows a longitudinal section of solar cells arranged
one behind the other and next to each other, wherein first wire
conductors run in the longitudinal direction over the upper sides
of the successively arranged solar cells, and the second wire
conductors rest against the lower side of the solar cells, and the
cross-connectors run in each case between the first wire connectors
and the second wire connectors,
[0079] FIG. 8 shows a three-dimensional view from above according
to FIG. 7,
[0080] FIG. 9 shows a solar cell combination according to FIGS. 7
and 8 in a longitudinal section, wherein subsequently the
connection between the first and second wire conductors to the
cross-connector has been alternately disconnected,
[0081] FIG. 10 shows the solar cell combination according to FIG. 9
in a three-dimensional view from above,
[0082] FIG. 10a shows a further variant, similar to FIG. 9, but
with different first and second wire conductors,
[0083] FIG. 10b shows a schematic illustration of the cutting
device,
[0084] FIG. 10c shows an illustration of a (lower) first wire field
F1 from second wire conductors 3.1,
[0085] FIG. 10d shows an illustration of solar cells 2 positioned
on the first wire field F1,
[0086] FIG. 10e shows an illustration according to FIG. 10d with
cross-connectors 4,
[0087] FIG. 10f shows an illustration according to FIG. 10e with a
second wire field F2 from first wire conductors 3,
[0088] FIG. 10g shows an illustration of the separated first and
second wire conductors 3, 3.2,
[0089] FIG. 10h shows an illustration of a solar cell combination
with first (upper) wire conductors 3 in the form of thin wires and
second (lower) wire conductors 3.1 in the form of wide bands,
[0090] FIG. 10i shows an illustration of a solar cell combination
with first (upper) wire conductors 3 in the form of thin wires and
second (lower) wire conductors 3.1 in the form of a full-surface
film,
[0091] FIG. 10k shows the work steps start with an empty carrier,
pulling out the back side wires, placing the cells, pulling out the
cross-connectors, and pulling out the front side wires,
[0092] FIG. 10l shows the transport of the carrier generated on the
matrix plate to the heating plate T.
[0093] FIG. 10M shows an embodiment in which wire conductors are
arranged on both sides of the solar cell.
[0094] FIGS. 11 to 18 show the method steps for producing a third
variant of a solar cell combination from solar cells by using first
wire conductors which run alternately between the upper side and
the lower side of the solar cells, and further contact elements in
the form of second wire conductors which are parallel to the first
wire conductors and which run alternately opposite to the first
wire conductors between the lower sides and the upper sides of the
solar cells, wherein
[0095] FIG. 11 shows a longitudinal section of solar cells arranged
one behind the other and next to each other, wherein the first wire
conductor runs over the upper side and the lower side of the
adjacent solar cells, and the second wire conductor runs oppositely
thereto between the lower side and the upper side of the adjacent
solar cells,
[0096] FIG. 12 shows a three-dimensional view according to FIG. 11
from above,
[0097] FIG. 13 shows an enlarged three-dimensional view according
to FIG. 11 from above, wherein, however, no printed strip
conductors were used,
[0098] FIG. 14 shows a longitudinal section of solar cells arranged
one behind the other and next to each other according to FIG. 11,
wherein the first and the second wire conductors were alternately
separated between successively arranged solar cells so that a
series connection has been generated,
[0099] FIG. 15 shows a three-dimensional view according to FIG. 14
from above,
[0100] FIG. 16 shows a three-dimensional view of a string according
to variant 3 with only one first and one second wire conductor,
[0101] FIG. 17 shows the illustration of a weaving device for
producing a solar cell combination according to variant 3,
[0102] FIG. 18 shows detail X according to FIG. 17.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0103] FIGS. 1 to 6 illustrate the method steps for producing the
first variant of a solar cell combination 1 from solar cells 2 by
using first wire conductors 3 and further contact elements in the
form of cross-connectors 4 running transverse to said first wire
conductors.
[0104] FIGS. 1 and 2 illustrate a first production step wherein a
multiplicity of solar cells 2 were placed next to each other and
one behind the other onto a non-illustrated support. A multiplicity
of first continuous wire conductors 3 were positioned over the
solar cells 2 in the longitudinal direction, and cross-conductors 4
were placed transverse to and above the first wire conductors 3 and
in each case between a row of successively arranged solar cells 2
and also spaced apart from the successively arranged solar
cells.
[0105] In the FIGS. 1 and 2, a separating line T is indicated in
each case directly before a solar cell 2. FIG. 2 shows that on the
surface of the solar cells 2, strip conductors 5 are printed
transverse to the first wire conductors 3. The solar cells 2
positioned relative to each other, the first wire conductors 3 and
the cross-connectors 4 are now connected to each other and thus
contacted, and thus an intermediate combination 1.1 is produced.
This is preferably carried out through soldering. Subsequently, the
first wire conductors 3 are separated along the separating line T
so that a plurality of rows R1, R2 . . . of solar cells 2 arranged
next to each other are generated which comprise a protruding region
B of first wire conductors 3 and two cross-conductors 4 contacted
therewith (a first row R1 is shown in FIG. 3).
[0106] FIG. 4 shows two rows R1, R2 of solar cells 2 which are to
be connected to each other. The rows R1, R2 are positioned in such
a manner that the two cross-conductors 4 of the region B of the
first row R1 are positioned below the lower side of the solar cells
2 of the following row R2. For this purpose, the first row R1 rests
on an assembly support 6. Now, the second row R2 is placed in the
direction of the arrow onto the assembly support 6 and thus onto
the region B of the first row R1 and thereby onto the
cross-conductors 4 of the first row R1. As a result, the region B
of the first row is bent toward the assembly support 6 as shown in
FIG. 5, in which in this manner three rows R1 to R3 are positioned
relative to each other. The rows which are positioned relative to
each are now connected to each other, e.g., through soldering, so
that the cross-conductors 4 are contacted on the lower side of the
adjacent row of the solar cells 2.
[0107] A solar cell combination 1 produced with this first method
is illustrated in a three-dimensional view in FIG. 6. Three rows R1
to R3 of solar cells 2 were connected to each other. Here, over
each solar cell 2, six first wire conductors 3 are fed to the lower
side of the solar cell 2 adjoining in the longitudinal direction.
In each case two cross-conductors 4 extend over the solar cell rows
R1, R2 and are arranged between the lower sides of the solar cells
2 and the first wire conductors 2 which extend to the lower side of
the solar cells (see FIG. 5).
[0108] According to a non-illustrated method variant, this
combination can also be produced in that in the first method step,
the cross-conductors are not contacted over the first wire
conductors but are contacted directly on the lower side of a row of
solar cells. In this case too, the first wire conductors 3 are
separated such that a plurality of rows are generated and the
protruding regions B of the rows are positioned below the lower
sides of adjacent solar cells of the adjoining row and are
contacted with these solar cells.
[0109] The method steps of a second variant for producing a solar
cell combination are shown in the FIGS. 7 to 10. Likewise,
longitudinally extending first wire conductors 3 are used. The
further contact elements are configured in the form of
cross-conductors 4 running transverse to the first wire conductors
and to second wire conductors 3.1 which are parallel to the first
wire conductors 3 and which run on the lower side of the solar
cells 2.
[0110] FIG. 7 illustrates the longitudinal section of solar cells 2
arranged one behind the other and next to each other, wherein first
continuous wire conductors 3 run in the longitudinal direction over
the upper sides of the successively arranged solar cells 2, and
second continuous wire conductors 3.1 rest against the lower side
of the solar cells 2, and the cross-conductors 4 run in each case
between and transverse to the first wire conductors 3 and the
second wire conductors 3.1, and run in each case between the
successively arranged solar cells 2.
[0111] FIG. 8 shows the three-dimensional view from above according
to FIG. 7. It is shown here that the solar cells 2 successively
arranged in the longitudinal direction are provided on their upper
side in each case with a plurality of continuous first wire
conductors 3 and are provided on their lower side with a plurality
of second wire conductors 3 which are parallel to said first wire
conductors and offset thereto in the transverse direction. It is
shown that the cross-conductors 4 extend perpendicular to the first
and second wire conductors 3, 3.1 in the transverse direction
between them and between the solar cells 2. Preferably, first the
second wire conductors 3.1, then the solar cells 2 and the
cross-conductors 4, and subsequently the first wire conductors 3
are positioned and subsequently soldered, e.g., in a continuous
process, so as to form an intermediate combination 1.1 (see FIGS. 7
and 8).
[0112] This intermediate combination 1.1 is not yet functional; the
desired interconnection has still to be generated by separating the
first and seconds wire conductors.
[0113] For implementing a series connection in the intermediate
combination 1.1, the first and second wire conductors 3, 3.1 are
alternately disconnected from the cross-conductor 4. A longitudinal
section after separating the connection is shown in FIG. 9 in a
longitudinal section and in FIG. 10 in a three-dimensional view
from above. Only then, the functional solar cell combination
connected in series according to FIGS. 9 and 10 is obtained. Shown
therein are the gaps 7 generated in the first and second wire
conductors 3, 3.1 through the separation, through which gaps the
connection to the cross-conductors is alternately disconnected so
that a suitable interconnection between the solar cells 2 and the
first and second wire conductors 3, 3.1 has been generated.
[0114] A longitudinal section of a further variant is shown in FIG.
10a. Here, the first wire conductors 3 (first electrode) and the
second wire conductors 3.1 (second electrode) are made from
different materials and are likewise applied as continuous wires
first to both sides of the solar cells, wherein the
cross-connectors 4 were positioned between the first and second
wire conductors 3, 3.1 and between two adjacent solar cells 2, and
after generating an electrical contact between the first electrode
(wire conductor 3.1) and the back side (here lower side) of the
solar cell 2 and also between the second electrode (wire conductor
3.1) and the front side (here upper side) of the solar cell 2, the
connection of the two electrodes (wire conductors 3.1, 3.2) was
implemented, and then, as illustrated here, the superfluous and
disturbing wire bridges were removed so that alternately between
every second wire conductor 3, 3.1 to the cross connector 4, a kind
of a gap 7 has been formed so as to bring the (previously still
short-circuited) cells into an electrically useful connection
(parallel or series connection).
[0115] Cutting out has been carried out, e.g., by means of a laser
or, as illustrated, a self-centering cutting device which exerts
during cutting no forces onto the wires, as schematically
illustrated in FIG. 10b.
[0116] The cutting device consists, e.g., of blades S that can be
moved in pairs relative toward each other, wherein here a plurality
of blades S are provided which, corresponding to the shape of the
illustrated first wire conductors 3 to be cut, which have a
circular cross-section, are curved at their cutting edges S1. In
this case, the cutting edges S1 have a concave curvature. The first
wire conductors 3 illustrated in grey were cut by the blades S.
[0117] In the case of wire conductors having an angular (e.g.,
rectangular) cross-section, the cutting edges are preferably
implemented substantially linearly (not illustrated).
[0118] It is possible to adjust the cutting device by means of a
likewise non-illustrated camera system using the cell edges of the
solar cells as a reference.
[0119] In the illustrative embodiment according to FIG. 10c, two
fields F1, F2 of substantially parallel first and second wire
conductors 3, 3.1 are used.
[0120] The first wire field F1 illustrated here with lower second
wire conductors 3.1 is laid over the entire length of the string or
matrix to be produced and is spanned in the longitudinal direction
of the wire conductors. After in each case two first wire
conductors 3.1 which are arranged at a smaller spacing from each
other, a larger spacing from the next two second wire conductors
3.1 is provided here. Subsequently, the solar cells 2 are
positioned with their back sides above said first wire field F1
(FIG. 10d). If necessary, the contact between the back side of the
solar cells 2 and the first wire field F1 can already be
generated.
[0121] In the spaces between the cells of the solar cells 2, a
contact element in the form a cross-connector 4 can be placed (FIG.
10e) so as to implement later the contact between first and second
wire fields F1, F2. The contact elements/cross-connectors 4 have a
thickness corresponding to the thickness of the solar cells 2; in
this manner, no pressure is exerted onto the cell edge of the solar
cell 2.
[0122] In the next step, the second wire field F2, which is formed
from first wire conductors 3 running parallel to each other, is
arranged and spanned, parallel to the first wire field F1, over the
upper sides of the solar cells 2 and over the contact
elements/cross-connectors 4, wherein the second wire field F2, as
illustrated in FIG. 10f, is arranged offset to the first wire field
F1. The first wire conductors 3 of the second upper wire field F2
are illustrated brighter here than the second wire conductors 3.1
of the first wire field F1 located at the bottom here. (The first
and second wire conductors 3, 3.1 can also lie one above the other
in a substantially aligned manner--not illustrated here.) The
electrical connection between the wire fields F1, F2 and thus
between first wire conductors 2 and second wire conductors 3.1 and
the solar cell 2, and also between the first wire field F1 (second
wire conductors 3.1) and the second wire field F2 (first wire
conductors 3) and contact element/cross connector 4 is established.
For this, different technologies can be used.
[0123] Finally, still superfluous connections are separated
according to FIG. 10g so that gaps 7 are created between the second
wire conductors 3.1, which are arranged here below the solar cells
2, and the cross-connectors 4, which gaps are in the illustration
on the left side of the cross-connector 4, and wherein gaps 7 are
also formed between the upper first wire conductors 3 and the cross
connector 4, which gaps are arranged here on the right side of the
cross connector 4, so as to establish a suitable
interconnection.
[0124] The separating cut can be carried out mechanically or by
means of laser, as described above.
[0125] In addition to the aforementioned illustrative embodiments,
it is also possible to use wider electrode structures on the back
side of the solar cells 2. This reduces the contact resistances for
the current flow from cell to cell. Using wide electrode structures
on the front side would result in increased shading.
[0126] According to the invention, thus, a second wire field F2
from first thin wire conductors 3.1, analogous to the exemplary
embodiment according to FIGS. 10c to 10g, is used on the front side
of the solar cells 2. In this manner, an optimized low power loss
caused by shading and resistance is implemented. On the back side
of the solar cells 2, second wire conductors 3.1 in the form of
wider contact ribbons up to the size of bands are used. In this
manner, the power losses in the contact structure on the back side
can be reduced to a negligible level. Here too, after contacting
the components, areas are punched out or otherwise cut out between
the first wire conductors 3 (thin wires) and the cross connectors 4
so that gaps 7 are created, and areas are also removed between the
second wire conductors 3.1 (metal bands) and the cross-connectors 4
so that likewise gaps 7 are created, thereby establishing the
desired interconnection. By using contact bands, the
production-related expenditures for separating are reduced.
[0127] According to a further illustrative embodiment, which is
depicted in FIG. 10i, it is also possible to form the back side
contact of the solar cells 2 from a metal film that replaces a
plurality of second wire conductors 3.1, which metal film has been
designated here also with 3.1 and which, e.g., is soldered, glued
or fastened with laser welding spots over the full surface on the
cell back of the solar cell 2. One side of the film 3.1 protrudes
beyond the cell edge of the solar cell 2.
[0128] For compensating the wafer thickness and for mechanical
reinforcement, a contact element that is not illustrated here can
be applied onto the protruding portion of the film, or the
protruding portion of the film is folded without an additional
contact element. All this can take place in an upstream
pre-production process so that the metal film is already contacted
with the back side of the solar cells before being arranged to form
the cell combination and is therefore pre-assembled.
[0129] Subsequently, the prepared wafers are arranged in string or
matrix form, and the thin wires in the form of first wire
conductors 3, as in the preceding examples, are positioned as wire
field F2 over the string/the matrix and are contacted with the cell
front of the solar cells and with the protruding portion of the
film 3.1 of the adjacent cell.
[0130] Analogous to the aforementioned illustrative embodiments,
gaps 7 are also generated.
[0131] Furthermore, it is possible to position the wire electrodes
and the solar cells 2 first on a movable matrix carrier M in a
first work station (FIG. 10k). Said matrix carrier is ideally made
of a material that has a high thermal conductivity and low heat
capacity, e.g., made of anodized aluminum. FIG. 10k shows from left
to right the work steps a) start with empty matrix carrier M, b)
pulling out the back side wires in the form of a multiplicity of
thin second wire conductors 3.1 (second electrode) which are
aligned substantially parallel to each other, c) placing the cells
2 over the second wire conductors 3.1 and pulling out the
cross-connectors 4 in each case between two adjacent cells and
perpendicular to the second wire conductors 3.1, and d) pulling out
the front side wires in the form of a multiplicity of first wire
conductors 3 (first electrode) over the upper sides of the solar
cells 2 and the matrix carriers M produced in this manner. The
first and the second wire conductors 3, 3.1 are arranged parallel
to each other and are aligned here one above the other, and are
present in the same quantity.
[0132] With this variant it is possible in only one step to contact
the matrix of solar cells, wire conductors and cross-connectors
which, for the time being, are only horizontally positioned
relative to each other, wherein said matrix is received in the
matrix carrier M.
[0133] An assumed time per step of in each case 5 s for pulling out
the electrodes (wire conductors 3, 3.1) and the cross-connectors 4,
and of 1 s for each solar cell 2 results in a processing time of
only 75 s in the first work station. Cells, electrodes and
cross-connectors are fixed through optionally vertically movable
positioning aids, and the electrodes and cross-connectors are held
at their ends by means of suitable clamping devices.
[0134] Subsequently, the matrix carrier M loaded according to FIG.
10, illustration d, is transferred from the first work station to a
second work station. The latter is characterized by a structured
heating plate T into which negative structure elements on the back
side of the matrix carrier fit, see FIG. 10L. By structuring the
heating plate T and the matrix carrier M, the latter can be made
very thin and thus in a highly heat-conducting manner underneath
the solar cells--possibly facilitated by a black anodized
layer--while the webs on the back side ensure the necessary
mechanical stiffness and also increase the surface area for the
heat transfer.
[0135] The heating plate T is heated to a temperature close to but
below the melting temperature of the solder. After a short heating
period, the electrodes are soldered together with the solar cells
and the cross-connectors and as a result, contacting of a
multiplicity of solar cells with first and second wire conductors
and cross-connectors is established in only one step. Of course,
instead of a multiplicity of thin second wire conductors, a few
metal bands or a metal film can also be used as a second
electrode.
[0136] Depending on the required time, separating the electrodes
(wire conductors 3, 3.1) can already be carried out in the second
work station, e.g., parallel to or with a delay to the soldering
process. Subsequently, the matrix carrier is transported to a
non-illustrated third work station.
[0137] The latter can be provided with a cooling plate analogous to
the second work station so as to accelerate cooling of the matrix
carrier. In this work station--if not carried out in station
2--separating the wire fields takes place.
[0138] In the case that the above-mentioned positioning aids and
clamping devices can be retracted (e.g. spring-loaded into the
stiffening structure elements on the back side of the carrier) or
are located considerably outside of the matrix, the embedding
material (e.g., EVA) and the module glass plate can subsequently be
deposited and fixed on the carrier. Thereafter, the carrier
together with the matrix, the embedding material and the glass is
turned, the fixation of the glass is released and the carrier is
lifted. For further processing, the module glass plate is then
further treated in a conventional manner (e.g., applying the second
layer of EVA and the back film and laminating). Through this it is
avoided that the matrix has to be transported by means of grippers,
vacuum suction cups or Bernoulli grippers.
[0139] An advantage of this arrangement is the parallelization of
the time-consuming work steps such as the cell positioning and the
soldering process. This also reduces the residence time on the
heating plate. The cell matrix together with the sensitive solder
joints and the thin electrodes are always supported by the matrix
carrier or, in the further course, by the glass plate.
[0140] Depending on the embodiment, the first and/or second wire
conductors are separated between the solar cells after contacting
in the matrix carrier so that the desired interconnection is
created. This is preferably carried out in the matrix carrier or in
a further device with a suitable cutting/separating unit.
[0141] In contrast to the aforementioned exemplary embodiments in
which cross-connectors were used, it is also possible to connect
and contact the first and second wire conductors 3, 3.1 directly to
each other; this is carried out mechanically in that the wire
conductors 3, 3.1 are fed to each other and, e.g., are bent and
connected to each other, e.g., by crimping or soldering. This
preferably takes place in the still spanned state of the wire
conductors 3, 3.1. However, it is also possible to establish the
direct connection between the first and second wire conductors
after they have been separated for a suitable interconnection. FIG.
10M shows an exemplary embodiment in which the first and second
wire conductors 3, 3.1, which are arranged on both sides of the
solar cell 2, have been directly connected to each other and have
been provided with suitable gaps 7 by separating the wire
conductors. This variant has the advantage that the
cross-connectors can be eliminated.
[0142] The FIGS. 11 to 18 illustrate the method steps and a device
for producing a further variant of a solar cell combination 1 from
solar cells 2 by using first wire conductors 3 which run
alternately between the upper side and the lower side of the solar
cells 2 and using further contact elements in the form of second
wire conductors 3.1 which are parallel to the first wire conductors
3 and which run alternately opposite to the first wire conductors 3
between the lower sides and the upper sides of the solar cells
3.
[0143] FIG. 11 illustrates the longitudinal section of solar cells
2 arranged one behind the other and next to each other, wherein a
continuous first wire conductor 3 runs over the upper side and the
lower side of the adjacent solar cells 3, and the continuous second
wire conductor 3.1 runs opposite thereto between the lower side and
the upper side of the adjacent solar cells 2, and the
three-dimensional view according to FIG. 11 is illustrated from
above in FIG. 12. The solar cells are provided on their upper side
with strip connectors 5 which are printed thereon transverse to the
first and second wire conductors. FIG. 13 illustrates an
intermediate combination 1.1 on which no strip connectors are
printed, as a result of which the manufacturing complexity is
decreased and costs are considerably reduced. After the solar cells
were combined with the first and second wire conductors to form an
intermediate combination 1.1 and were contacted by soldering, it is
required, as in variant 2, to separate the wire conductors
according to the desired interconnection so that the desired solar
cell combination is created.
[0144] FIG. 14 shows a longitudinal section and FIG. 15 shows the
three-dimensional view of solar cells 2 arranged one behind the
other and next to each other, wherein alternately between
successively arranged solar cells 2, the first and second wire
conductors 3, 3.1 were separated so that through the gaps 7
generated during separating (preferably by means of laser), a
series connection is formed and the desired solar cell combination
1 is created.
[0145] FIG. 16 illustrates the three-dimensional view of a string S
produced according to variant 3 with solar cells 2 which were
contacted with only one first and one second wire conductor 3, 3.1.
Here too, there are gaps 7 due to the separation of the wire
conductors 3, 3.1 and as a result, a series connection has been
implemented.
[0146] FIG. 17 shows the schematic diagram of a device 10 for
producing a solar cell combination or an intermediate combination
according to variant 3, and the detail according to FIG. 17 is
shown in FIG. 18. Through a first roll feeder, a multiplicity of
first wire conductors 3 arranged next to each other and a
multiplicity of wire conductors 3.1 arranged therebetween are fed
to the weaving device 12. The wire conductors 3, 3.1 are
alternately moved upward and downward according to the arrow by
means of weaving rolls 13, 14. In each case inbetween, a row of a
plurality of solar cells 2 is inserted by means of a cell handling
device 15 and moved in the transport direction and subsequently,
the first and second wire conductors 3, 3.1 are spanned around. In
order to avoid breakage of the solar cells, a downholder 16 is
provided which keeps the wire conductors 3, 3.1 in the extension
plane of the solar cells 2 during the weaving process.
[0147] It is possible with all three variants to produce a solar
cell combination that forms a complete solar cell module or
comprises a multiplicity of solar cell modules and is then
separated into individual modules.
[0148] With the solution according to the invention, the production
of solar cell modules is revolutionized.
[0149] The foregoing description and examples have been set forth
merely to illustrate the invention and are not intended to be
limiting. Since modifications of the described embodiments
incorporating the spirit and substance of the invention may occur
to persons skilled in the art, the invention should be construed
broadly to include all variations within the scope of the appended
claims and equivalents thereof.
* * * * *