U.S. patent application number 13/320586 was filed with the patent office on 2012-07-19 for composite current collector and methods therefor.
This patent application is currently assigned to AIC BLAB. Invention is credited to Frank Lev, Leonid Rabinovich.
Application Number | 20120183847 13/320586 |
Document ID | / |
Family ID | 43126468 |
Filed Date | 2012-07-19 |
United States Patent
Application |
20120183847 |
Kind Code |
A1 |
Lev; Frank ; et al. |
July 19, 2012 |
COMPOSITE CURRENT COLLECTOR AND METHODS THEREFOR
Abstract
Contemplated bipolar lead acid batteries include a bipole
assembly with a monolithic or composite current collector that is
in contact with the PAM. Especially preferred current collectors
have a substrate formed from pure lead and grid formed from a lead
alloy, wherein the interface between the grid and substrate is
formed via electroforming and/or resistance welding. Particularly
preferred batteries are configured as deep cycle batteries and have
a low ratio between the surface area of the grid and the weight of
the PAM.
Inventors: |
Lev; Frank; (Thornhill,
CA) ; Rabinovich; Leonid; (Thornhill, CA) |
Assignee: |
AIC BLAB
Alameda
CA
|
Family ID: |
43126468 |
Appl. No.: |
13/320586 |
Filed: |
May 18, 2010 |
PCT Filed: |
May 18, 2010 |
PCT NO: |
PCT/US10/35235 |
371 Date: |
March 7, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61179609 |
May 19, 2009 |
|
|
|
Current U.S.
Class: |
429/210 ;
219/91.2 |
Current CPC
Class: |
H01M 4/667 20130101;
H01M 4/661 20130101; H01M 10/18 20130101; H01M 4/668 20130101; H01M
4/73 20130101; H01M 4/82 20130101; H01M 4/685 20130101; H01M 4/68
20130101; H01M 4/72 20130101; Y02E 60/10 20130101 |
Class at
Publication: |
429/210 ;
219/91.2 |
International
Class: |
H01M 4/73 20060101
H01M004/73; B23K 11/10 20060101 B23K011/10 |
Claims
1. A bipole assembly for use in a bipolar lead acid battery,
comprising: a welded or monolithic composite current collector that
comprises a conductive substrate formed from a first metal
composition and an electroformed grid structure; wherein the
electroformed grid structure is conductively coupled to a first
side of the substrate and formed from a second metal composition,
and wherein the first and second metal composition are not the
same.
2. The bipole assembly of claim 1 wherein the first metal
composition is pure lead and wherein the second metal composition
is a lead alloy.
3. The bipole assembly of claim 2 wherein the lead alloy comprises
an alkaline earth metal, an alkaline metal, or tin.
4. The bipole assembly of claim 1 further comprising a
non-conductive grid coupled to the substrate on a second side of
the substrate that is opposite the first side, and further
comprising a negative active material (NAM) contacting the
non-conductive grid and the second side of the substrate.
5. The bipole assembly of claim 4 wherein the negative active
material (NAM) is in-tank formed negative active material
(NAM).
6. The bipole assembly of claim 1 further comprising a positive
active material (PAM) contacting the electroformed or resistance
welded grid structure and the first side of the substrate.
7. The bipole assembly of claim 6 wherein the positive active
material (PAM) is in-tank formed positive active material
(PAM).
8. The bipole assembly of claim 7 wherein the grid structure has a
surface area S.sub.grid and wherein the PAM has a weight W.sub.PAM,
and wherein the ratio of W.sub.PAM to S.sub.grid is between
0.65-1.1 g/cm.sup.2.
9. The bipole assembly of claim 7 wherein the grid structure has a
surface area S.sub.grid and wherein the PAM has a weight W.sub.PAM,
and wherein the ratio of W.sub.PAM to S.sub.grid is between 0.8-1.0
g/cm.sup.2.
10. The bipole assembly of claim 1 wherein the substrate is
configured as a composite substrate in which a non-conductive
polymer carrier is coupled to the substrate opposite the first
side, wherein the polymer carrier has a plurality of openings that
allow formation of a conductive path between the substrate and
another conductive material located on an opposite side of the
carrier.
11. A bipolar lead acid battery comprising the bipole assembly of
claim 1.
12. The bipolar lead acid battery of claim 11 wherein the battery
is configured as a valve regulated lead acid battery.
13. The bipolar lead acid battery of claim 11 wherein the battery
is configured as a deep cycle battery.
14. A method of forming a bipole assembly for a bipolar lead acid
battery, comprising a step of resistance welding a lead alloy grid
structure onto a lead substrate, or gradually building a lead alloy
grid structure onto a lead substrate, or gradually forming a lead
substrate onto a lead alloy grid structure to thereby form a
composite or monolithic current collector structure.
15. The method of claim 14 wherein the step of gradually building
is selected from the group consisting of electroforming,
electroplating, vapor depositing, redox depositing.
16. The method of claim 14 wherein the lead alloy comprises an
alkaline earth metal, an alkaline metal, or tin.
17. The method of claim 14 further comprising a step of coupling to
the lead alloy grid structure and the first side of the substrate a
positive active material (PAM).
18. The method of claim 16 wherein the lead alloy grid structure
has a surface area S.sub.grid and wherein the PAM has a weight
W.sub.PAM, and wherein the ratio of W.sub.PAM to S.sub.grid is
between 0.65-1.1 g/cm.sup.2.
19. The method of claim 16 wherein the lead alloy grid structure
has a surface area S.sub.grid and wherein the PAM has a weight
W.sub.PAM, and wherein the ratio of W.sub.PAM to S.sub.grid is
between 0.8-1.0 g/cm.sup.2.
20. The method of claim 14 further comprising a step of coupling a
non-conductive grid to the lead substrate on a side of the
substrate that is opposite the side onto which the grid structure
is formed, and further in-tank forming a negative active material
(NAM) onto the non-conductive grid and the opposite side.
21. The method of claim 14 wherein the lead substrate is configured
as a composite substrate in which a non-conductive polymer carrier
is coupled to the lead substrate opposite the side onto which the
grid structure is formed, wherein the polymer carrier has a
plurality of openings that allow formation of a conductive path
between the lead substrate and another conductive material located
on the opposite side of the carrier.
Description
[0001] This application claims priority to our copending U.S.
provisional application with the Ser. No. 61/179,609, which was
filed May 19, 2009.
FIELD OF THE INVENTION
[0002] The field of the invention is current collectors, and
especially as it relates to current collectors in bipolar lead acid
batteries (BLAB).
BACKGROUND OF THE INVENTION
[0003] It is well-known in the art of lead acid battery manufacture
that pure lead has a relatively high resistance to corrosion in
sulfuric acid containing electrolytes due to the insulating layer
of PbSO.sub.4/PbO.sub.x (1<x<2) that is formed in the
electrolyte. Thus, and at least at first glance it appears
desirable to form in a lead battery a positive plate with a grid
structure made from pure lead since the PbSO.sub.4/PbO.sub.x layer
acts as semi-permeable membrane and blocks the transport of
SO.sub.4.sup.2- and/or HSO.sub.4.sup.-species. In most cases, the
PbSO.sub.4/PbO.sub.x layer has a thickness of about four microns
and tends to stay at that value through the life of a lead acid
battery cell, and cells made with pure lead grids experience under
most circumstances no corrosion while float-charged.
[0004] Where the lead acid battery is a bipolar lead acid battery,
it is especially desirable to have a durable and
corrosion-resistant substrate. Consequently, pure lead has been
considered a prime material for such substrate to capitalize on the
protective properties of the PbSO.sub.4/PbO.sub.x layer. It is
known from U.S. Pat. No. 3,806,696 that pure lead grids and pure
lead plates can be welded together to provide a composite collector
structure in which the resultant weld is of low internal impedance
and is relatively thick for increased oxidation and corrosion
resistance. Such methods advantageously reduce the resistance at
the grid/lead interface. However, lead grid structures from pure
lead are unfortunately not suitable for deep cycling applications
as the PbSO.sub.4/PbO.sub.x layer that is formed during operation
also acts as an insulator with very high electric resistance, which
in turn results in a premature capacity loss of the cell. To avoid
such drawbacks, almost all production battery grids are made of
various non-welded lead alloys (e.g., Odyssey lead acid battery,
containing at least 0.7% Sn in the lead alloy).
[0005] It is also known from U.S. Pat. No. 6,620,551 that the
collector for a lead acid battery can be formed from a pure lead
substrate and an additional surface layer that comprises a Sn-free
lead alloy composition (most typically including an alkaline metal
or alkaline earth metal). This and all other extrinsic materials
discussed herein are incorporated by reference in their entirety.
Where a definition or use of a term in an incorporated reference is
inconsistent or contrary to the definition of that term provided
herein, the definition of that term provided herein applies and the
definition of that term in the reference does not apply. While such
collectors may reduce or even entirely avoid the formation of the
PbSO.sub.4/PbO.sub.x layer, other disadvantages nevertheless
remain. For example, manufacture of such composite structures will
typically require lamination, which tends to be instable over
prolonged times. Furthermore, the amount of added alkaline metal or
alkaline earth metal is typically relatively high and thus often
interferes with material properties of the alloy.
[0006] Thus, even though numerous current collectors are known in
the art, there is still a need to provide improved current
collectors, especially for BLAB.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to devices and methods for
bipolar batteries, and especially bipolar lead acid batteries with
substantial improved performance and power-to-weight ratio in which
a monolithic current collector combines advantages of improved
resistance to oxidation and conductivity.
[0008] In one aspect of the inventive subject matter, a bipole
assembly for use in a bipolar lead acid battery is contemplated,
wherein the assembly includes a monolithic composite current
collector that comprises a conductive substrate formed from a first
metal composition and an electroformed grid structure. Most
preferably, the electroformed grid structure is conductively
coupled to a first side of the substrate and formed from a second
metal composition.
[0009] In especially preferred aspects, the first metal composition
is pure lead and the second metal composition is a lead alloy
(e.g., alloyed with an alkaline earth metal, an alkaline metal,
and/or tin). Contemplated assemblies will also preferably include a
non-conductive grid that is coupled to the substrate on a second
side of the substrate that is opposite the first side, and a
negative active material (NAM) contacting the non-conductive grid
and the second side of the substrate. A positive active material
(PAM) typically contacts the electroformed grid structure and the
first side of the substrate. Where the battery is configured as a
deep cycle battery, it is generally preferred that the
electroformed, or cast grid structure has a surface area
S.sub.grid, the PAM has a weight W.sub.PAM, and that the ratio of
W.sub.PAM to S.sub.grid is between 0.65-1.1 g/cm.sup.2, and more
preferably between 0.8-1.0 g/cm.sup.2. While not limiting to the
inventive subject matter, it is also contemplated that the
substrate may be configured as a composite substrate in which a
non-conductive polymer carrier is coupled to the substrate opposite
the first side, wherein the polymer carrier has a plurality of
openings that allow formation of a conductive path between the
substrate and another conductive material located on an opposite
side of the carrier.
[0010] Therefore, and viewed from a different perspective, a
bipolar lead acid battery is contemplated that includes the above
bipole assembly, most typically configured as a valve regulated
lead acid battery. It is further especially preferred that such
batteries are configured as a deep cycle battery.
[0011] In another aspect of the inventive subject matter, a method
of forming a current collector is contemplated which comprises a
step of electroforming a composite structure in which a lead alloy
grid and a lead substrate form a monolithic structure. Thus, and
viewed from a different angle, a method of forming a bipole
assembly for a bipolar lead acid battery may include a step of
gradually building a lead alloy grid structure onto a lead
substrate or gradually forming a lead substrate onto a lead alloy
grid structure to thereby form a monolithic current collector
structure.
[0012] It is especially preferred that the step of gradually
building comprises electroforming, electroplating, vapor
depositing, and/or redox depositing. In further contemplated
methods, the lead alloy grid structure and the first side of the
substrate are coupled to a PAM. Most preferably, deep cycle
batteries are formed such that the lead alloy grid structure has a
surface area S.sub.grid, the PAM has a weight W.sub.PAM, and the
ratio of W.sub.PAM to S.sub.grid is between 0.65-1.1 g/cm.sup.2,
and even more typically between 0.8-1.0 g/cm.sup.2.
[0013] It is still further contemplated that a non-conductive grid
is coupled to the lead substrate on the side of the substrate that
is opposite the side onto which the grid structure is formed, and
that a NAM is coupled to the non-conductive grid and the opposite
side. While not limiting to the inventive subject matter, it is
also preferred that in at least some aspects the lead substrate is
configured as a composite substrate in which a non-conductive
polymer carrier is coupled to the lead substrate opposite the side
onto which the grid structure is formed. In such configurations,
the polymer carrier has a plurality of openings that allow
formation of a conductive path between the lead substrate and
another conductive material located on the opposite side of the
carrier.
[0014] Various objects, features, aspects and advantages of the
inventive subject matter will become more apparent from the
following detailed description of preferred embodiments, along with
the accompanying drawing figures in which like numerals represent
like components.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1A is an exemplary photograph of a pure lead substrate
and FIG. 1B is an exemplary photograph of a lead alloy grid.
[0016] FIG. 2 is an exemplary schematic illustration of a bipole
assembly according to the inventive subject matter.
[0017] FIG. 3 is an exemplary valve regulated bipolar lead acid
battery according to the inventive subject matter.
[0018] FIG. 4 is a performance graph for an exemplary bipolar lead
acid battery according to the inventive subject matter.
[0019] FIG. 5 is a exemplary schematic illustration of a
quasi-bipolar assembly according to the inventive subject
matter.
DETAILED DESCRIPTION
[0020] The inventors have discovered that various monolithic
positive current collectors can be prepared for a BLAB in which the
benefits of a Sn/Pb alloy grid and the benefits of a pure lead
substrate are combined in an economically and technically desirable
manner. Monolithic current collectors of particularly preferred
devices and methods are electroformed such that the collector has
an alloyed grid (most typically SnPb alloy) portion that is
structurally and conductively continuous with a pure lead
substrate. Alternatively, the current collectors of further
particularly preferred devices and methods are welded composite
structures where the alloyed grid (most typically SnPb alloy) is
resistance welded to a pure lead substrate to so form the composite
collector.
[0021] Based on a series of experiments using prefabricated
off-the-shelf parts, the inventors discovered that when a pure lead
substrate (e.g., thin lead foil with a purity of at least 99 wt %
as shown in FIG. 1A) is welded to a Pb--Sn grid (e.g., 5 wt % Sn,
95 wt % Pb as shown in FIG. 1B), the electrical conductivity
between the substrate and the grid is significantly increased.
Among other reasons, the inventors contemplate that in such
composite devices the grid can be advantageously employed to
collect current from the positive active material (PAM) and to
convey it to the substrate via the welded joints, thus bypassing
the PbSO.sub.4/PbO.sub.x layer on the substrate that has a high
resistivity. While such composite collectors already provided many
desirable properties, welding a relatively thin (e.g., 0.15 mm)
lead foil to a likewise thin grid (e.g., 0.15 mm) proved to be a
challenging process that required special equipment and skills.
[0022] In an effort to circumvent the disadvantages associated with
the welding process, the inventors discovered that currently known
lead and lead alloy electroforming technology (see e.g., U.S. Pat.
No. 7,097,754; DSL Dresden Material-Innovation GmbH) can be applied
to form monolithic composite structures in which one part of the
composite structure (the grid) comprises a lead alloy (e.g., SnPb
alloy) and in which another part (the lead substrate) of the
composite structure comprises pure lead. Contemplated methods and
collectors formed with such methods will not only avoid laborious
welding processes to conductively couple a grid to a substrate, but
also advantageously allow formation of the composite structure in
many configurations and geometries in a highly automated and simple
manner.
[0023] The term "monolithic" in conjunction with a composite
structure is used to mean that the structure will include at least
two different materials that are joined to form a continuous
interface, wherein the interface does not include a binding
material disposed between the different materials, and wherein the
interface does not include a physical modification (e.g., heat
affected zone or melt zone) of at least one of the two different
materials. The term "formed" as used in conjunction with the grid
and/or substrate means that the grid and/or substrate is produced
in a gradual and additive process where material is added to the
nascent grid and/or substrate to so arrive at the final grid and/or
substrate structure. Furthermore, the term "pure" in conjunction
with the term "lead" refers to lead having a chemical purity of at
least 95 wt %, more typically at least 98 wt %, and most typically
at least 99.9 wt %.
[0024] Consequently, it should be recognized that the inventors
contemplate various bipole assemblies for use in bipolar lead acid
batteries, and that such assemblies will advantageously include one
or more monolithic current collectors in which a conductive
substrate is formed from a first metal composition (typically pure
lead) and in which a grid structure is formed from a second metal
composition (typically a lead alloy). Most preferably, contemplated
devices are electroformed, however, various alternative processes
are also deemed suitable and include electroplating, vapor
deposition, and deposition from a redox reaction (as described, for
example, in U.S. Pat. No. 6,548,122). Alternatively, resistance
welding (e.g., spot or seam welding) may be used to form the
composite current collector structure, which will exhibit almost
identical mechanical and electrochemical properties as the
aforementioned electroformed and, by definition, monolithic current
collector.
[0025] With respect to the substrate it is contemplated that the
substrate comprises lead or is made entirely from lead and has a
generally planar and relatively thin configuration. Thus, in most
typical aspects of the inventive subject matter, the substrate is a
pure lead foil having a thickness of between about 2 mm and 0.05
mm. The lead substrate may also be modified to include elements
other than lead to so increase stability against oxidation, or may
be a lead alloy to impart desirable characteristics. It should be
noted that where the lead foil is very thin (e.g., equal or less
than 0.1 mm), a conductive or non-conductive carrier may be
implemented to stabilize the structure. For example, suitable
carriers include non-conductive and oxidation resistant polymeric
materials (e.g., synthetic polymers such as PVDF, HDPE, and other
polymers known in the battery art), but also certain conductive
materials such as glassy carbon, Magnelli phase suboxide materials.
Where the carrier is non-conductive, it is especially preferred
that the carrier includes a plurality of transverse channels that
allow inclusion of a conductive material to so allow transfer of
electrons from one side of the carrier to the other side (see FIG.
5 below). Regardless of the nature of the carrier, it is typically
preferred that the carrier is relatively thin (e.g., having a
thickness of between 0.1 and 100 times the thickness of the
substrate) and is capable of retaining the substrate. Thus,
suitable carriers may be laminated, welded, or otherwise coupled to
the substrate. In still other aspects, the substrate may also be
deposited from a liquid or solid phase onto the carrier using vapor
deposition, electro-deposition, redox deposition, electroforming,
etc.
[0026] In less preferred aspects, metals and metal alloys other
than lead and lead alloys are also contemplated. For example
titanium, aluminum, lead or plastic substrates can be coated by Sn,
SnO2 or Ti4O7 to make them impervious to corrosion. Similarly, it
should be noted that the most preferred material for the grid is a
binary lead alloy comprising 0.4 to 0.9% Sn with the balance of
pure Pb.
[0027] Most preferably, and at least in part depending on the
choice of materials, it is preferred that at least one of the grid
structure and the substrate are electroformed in a process that
allows formation of a monolithic composite structure. For example,
a template may be structured such that a grid is built by
electroforming onto a spindle using a first material (e.g., lead
alloy), and that onto the so formed grid structure a pure lead
substrate is formed. Of course, it should be noted that the
monolithic composite structure may be formed in a reverse manner
where the substrate is formed first, and the grid structure is
formed in a subsequent step. For example, a mask may be applied to
the lead substrate to serve as a template for vapor or
electrochemical deposition of the lead alloy grid structure. The
exact configuration of the grid structure will depend on the size
and configuration of the substrate, and will further depend on the
particular use of the battery as further explained below.
[0028] Recognizing the critical role of the grid-to-PAM interface
under deep cycling duty, an optimization relationship between the
weight of PAM (W.sub.PAM) and area of the grid (S.sub.grid) that is
in contact with PAM was established in which .beta. is defined as
W.sub.PAM/S.sub.grid in a positive half cell. Among other grids
produced, especially suitable experimental grids had a .beta. value
of between about 0.5-1.3 g/cm.sup.2, more preferably between about
0.65-1.1 g/cm.sup.2, and most preferably between about 0.8-1.0
g/cm.sup.2, whereas a typical SLI (Start, Light, Ignition) battery
is considered to have a .beta. value of about 2.5 g/cm.sup.2. As
used herein, the term "about" in conjunction with a numeral refers
to a range of that numeral of +/-10%, inclusive. Furthermore, and
unless the context dictates the contrary, all ranges set forth
herein should be interpreted as being inclusive of their endpoints,
and open-ended ranges should be interpreted to include only
commercially practical values. Similarly, all lists of values
should be considered as inclusive of intermediate values unless the
context indicates the contrary.
[0029] In further especially preferred experiments, the grid
portion of the collector structure was designed to a .beta. value
of about 0.95 g/cm.sup.2 (using 42 g of PAM and 44 cm.sup.2 total
area of grid wires in contact with PAM). Remarkably, in such and
the above grids and substrates, sufficient area of the current
collecting surfaces was present to achieve uniform distribution of
the PAM in contact with the grid wires to improve the utilization
of PAM and increase cycle life, particularly for deep cycle
operation.
[0030] With respect to suitable negative active materials (NAM) it
should be appreciated that all known NAM are considered appropriate
for use herein. Thus, especially contemplated NAM includes various
lead-based pastes. As in other known batteries, the NAM is
preferably retained at the substrate using a non-conductive carrier
(grid) that is most preferably compression resistant. While not
limiting to the inventive subject matter, the non-conductive grid
is preferably manufactured from a synthetic polymer that is
resistant to acid and oxidative corrosion.
[0031] FIG. 2 schematically illustrates an exemplary bi-pole
assembly that includes a current collector (substrate/grid) in
which (1) is the positive active material, (2) is a plastic frame,
(3) is the current collector with (3a) being the grid and (3b) the
substrate, in which (4) is a plastic grid and in which (5) is the
negative active material (NAM). While in this example the grid and
substrate are shown as separate parts for better illustration, it
should be noted that in most preferred aspects the lead alloy grid
and substrate are a (preferably electroformed) monolithic
structure. Furthermore, it should be appreciated that multiple
bi-pole assemblies may be coupled together to so form a bipolar
lead acid battery. In still further preferred aspects, at least one
of the NAM and PAM are produced via in-tank formation. In such
methods, it is generally further preferred that the formation of
the NAM and/or PAM is done under a protective atmosphere to avoid
undesired oxidative reactions.
[0032] Consequently, the inventors also contemplate numerous
bipolar lead acid batteries in which multiple bi-pole assemblies
are coupled together in a manner well known in the art. Thus, and
in especially preferred aspects, a deep cycle bipolar lead acid
battery with highly desirable characteristics can be manufactured.
As used herein, the term "deep cycle" in conjunction with the term
"battery" refers to a battery that is designed to allow repeated
discharge (e.g., greater 20 times) of the battery to 20% of full
charge without adverse effects on the battery. Moreover, it should
be appreciated that in especially preferred aspects the lead acid
bipolar batteries contemplated herein are configured as a valve
regulated (recombinant) lead acid battery (VRLA). Consequently, it
is preferred that the electrolyte in such batteries may be a gelled
electrolyte or absorbed electrolyte (typically using a glass mat).
FIG. 3 depicts one such exemplary 12V 4 Ah VRLA in assembled
state.
EXAMPLES
[0033] In a typical experiment, a batch of 12V BLABs was prepared
in which the substrates and the grids of the current collectors
were welded to each other. These first generation batteries have
proven the feasibility and advantages of electroformed composite
current-collectors. It is expected that electroformed monolithic
current collectors will provide the same or even further improved
results. The cycling performance of such BLABs appeared to be
steady as can be readily taken from the data below. Moreover, the
BLABs demonstrated desirable capacity parameters as can be taken
from the data below. Based on these initial experiments and general
configurations, the inventors have constructed various additional
BLABs with the following characteristics:
[0034] Table 1 below depicts general parameters of the active
materials while Table 2 below lists various design parameters for
the lead substrate and grid. Table 3 below lists the weight of the
BLAB components, and Table 4 lists an estimate weight calculation.
Finally, Table 5 depicts exemplary performance data of the
BLAB.
TABLE-US-00001 TABLE 1 Active Density Width Height Thick Area
Volume Mass material (g/cm.sup.3) (cm) (cm) (cm) (cm.sup.2)
(cm.sup.3) (g) PAM 3.9-4.1 11.0 11.5 0.09 123.3 11.0 42.0-43.0 NAM
3.6-3.8 11.0 11.5 0.09 123.3 11.0 38.0-40.0
TABLE-US-00002 TABLE 2 Plastic Grid Foil Parameter frame
(Pb--Sn0.9%) Wire (Pb 99.99%) Mass (g) 3.6 4.4 0.18-0.20 23.50
Width (cm) 11.0 11.000 11.5 Height (cm) 11.5 0.09 11.9 Thick (cm)
12 .times. 12 wires 0.016 0.0152 Area (cm.sup.2) 4.3 0.99 136.85
Volume (cm.sup.3) 0.016 2.08 Density (g/cm.sup.3) 11.30 11.30
TABLE-US-00003 TABLE 3 Bipole (+)End-pole (-)End-pole Total weight
(g) Total weight (g) Total weight (g) 42 + 38 + 23.5 + 5 + 42 +
23.5 + 5 + 38 + 23.5 + 3.6 = 66 3.6 = 112 3.6 = 74
TABLE-US-00004 TABLE 4 Weight of Quantity Weight of Weight of No
Component component (g) (pc) subassembly (g) assembly (g) 1 Bi-pole
112.0 5 560.0 700.0 2 End-pole (+) 74.0 1 74.0 3 End-pole (-) 66.0
1 66.0 4 Separator 2.4 mm 4.8 6 28.8 332.0 5 Electrolyte/cell/total
50.5 6 303.0 6 End plates [12.5 .times. 110 .times. 110 mm] 114.0 2
228 378.0 7 Lid + bottom (4.0 .times. 55 .times. 118 mm] 31.0 2
62.0 8 Walls [4.0 .times. 55 .times. 110 mm] 29.0 2 58.0 9 PRV,
terminals, miscellaneous: 30.0 Total battery weight (kg)
1.4-1.5
TABLE-US-00005 TABLE 5 Charge Discharge Time OCV Voltage@ OCV Cycle
Time@ Time@ total, after Time end of after # CC, min CV, min min Ah
Wh 10 min min Ah Wh discharge, V 10 min 1 183 3.05 32.70 10.50
11.53 2 116 484 600 4.10 58.0 13.81 184 3.07 33.18 10.50 11.62 3
112 488 600 3.67 51.6 13.84 186 3.10 33.54 10.50 11.63
[0035] Typical performance data of a cycle life test of an
exemplary 12V bipolar battery prototype made to test the monolithic
current collectors are depicted in FIG. 4 in which 11 charge was
performed at CC@1.2 A, CV@2.45V, 10 hrs, and discharge was
performed at CC@1 A, cut off 1.75V/cell. As can be readily taken
from the data in Table 5 and FIG. 4, the battery operated as
expected with desirable performance characteristics.
[0036] FIG. 5 shows an exemplary view of an bipole assembly
configured as a quasi-bipole in which a non-conductive carrier 512
has openings 512' (dashed lines) that connect the respective
surfaces of the plate-shaped carrier. Placed in the openings are
lead elements 513 (or other conductive material) to so provide a
current connection between the surfaces. Most preferably, a
monolithic current collector (not shown) and a lead foil 515 are
laminated onto the carrier such that the lead elements electrically
connect the lead foils on the opposing surfaces. Onto this
assembly, negative and positive active materials are then applied
(not shown). Most typically, the monolithic current collector and
the lead foil have a thickness that is greater than the thickness
of the layers of negative and/or positive active materials. A
conductive tab 511 may be included where desired. Further
quasi-bipolar configurations and methods suitable for use herein
are described in our copending International application with the
publication number WO2010/019291, which is incorporated by
reference herein.
[0037] It should be apparent to those skilled in the art that many
more modifications besides those already described are possible
without departing from the inventive concepts herein. The inventive
subject matter, therefore, is not to be restricted except in the
spirit of the appended claims. Moreover, in interpreting both the
specification and the claims, all terms should be interpreted in
the broadest possible manner consistent with the context. In
particular, the terms "comprises" and "comprising" should be
interpreted as referring to elements, components, or steps in a
non-exclusive manner, indicating that the referenced elements,
components, or steps may be present, or utilized, or combined with
other elements, components, or steps that are not expressly
referenced. Where the specification claims refers to at least one
of something selected from the group consisting of A, B, C . . .
and N, the text should be interpreted as requiring only one element
from the group, not A plus N, or B plus N, etc.
* * * * *