U.S. patent application number 14/039644 was filed with the patent office on 2014-01-30 for lithium secondary battery having multi-directional lead-tab structure.
This patent application is currently assigned to LG CHEM, LTD.. Invention is credited to Bo Hyun Kim, Ji Hyun Kim.
Application Number | 20140030579 14/039644 |
Document ID | / |
Family ID | 46314111 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140030579 |
Kind Code |
A1 |
Kim; Bo Hyun ; et
al. |
January 30, 2014 |
Lithium Secondary Battery Having Multi-Directional Lead-Tab
Structure
Abstract
A lithium rechargeable battery, and more particularly, a lithium
rechargeable battery having a multidirectional lead-tab structure
is provided. The lithium rechargeable battery includes: an
electrode assembly in which a separator and an electrode plate
having a current collector, an active material, and a tab are
alternately stacked; a lead electrically connected to the tab; and
a battery case, wherein the lead is divided into a positive
electrode lead and a negative electrode lead, and at least one
positive electrode lead and at least one negative electrode lead
are provided. The lithium rechargeable battery is appropriate for
using a high current even while using a conventional lead-tab
size.
Inventors: |
Kim; Bo Hyun; (Daejeon,
KR) ; Kim; Ji Hyun; (Gyeonggi-do, KR) |
Assignee: |
LG CHEM, LTD.
Seoul
KR
|
Family ID: |
46314111 |
Appl. No.: |
14/039644 |
Filed: |
September 27, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13054974 |
Jan 20, 2011 |
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14039644 |
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PCT/KR2010/009129 |
Dec 20, 2010 |
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13054974 |
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Current U.S.
Class: |
429/153 |
Current CPC
Class: |
Y02E 60/10 20130101;
H01M 2/30 20130101; H01M 10/0436 20130101; H01M 10/0413 20130101;
H01M 2/266 20130101; H01M 10/052 20130101; H01M 10/0585
20130101 |
Class at
Publication: |
429/153 |
International
Class: |
H01M 2/26 20060101
H01M002/26 |
Claims
1. A lithium rechargeable battery comprising: an electrode assembly
in which a separator and an electrode plate having a current
collector, an active material, and a tab are alternately stacked; a
lead electrically connected to the tab; and a battery case, wherein
the lead is divided into a positive electrode lead and a negative
electrode lead, and at least two positive electrode leads and at
least two negative electrode leads are provided.
2. The lithium rechargeable battery of claim 1, wherein the
electrode assembly is formed by alternately stacking electrode
plates and separators so that tabs of electrode plates of the same
polarity have different axial direction positions, and the leads
are provided at positions corresponding to the tab positions.
3. The lithium rechargeable battery of claim 1, wherein the
electrode assembly is formed by alternately stacking electrode
plates and separators so that tabs of electrode plates of different
polarity have different axial direction positions, and the leads
are provided at positions corresponding to the tab positions.
4. The lithium rechargeable battery of claim 1, wherein the
electrode assembly has a rectangular cross-sectional shape, and the
positive electrode lead and the negative electrode lead are each
selectively provided at four sides of the electrode assembly.
5. The lithium rechargeable battery of claim 4, wherein the
positive electrode lead and the negative electrode lead are formed
in the same direction at one side of four sides of the electrode
assembly formed in a rectangular cross-sectional shape.
6. The lithium rechargeable battery of claim 4, wherein the
positive electrode lead and the negative electrode lead are each
dividedly formed at adjacent sides of four sides of the electrode
assembly formed in a rectangular cross-sectional shape.
7. The lithium rechargeable battery of claim 4, wherein the
positive electrode lead and the negative electrode lead are each
formed opposite to two opposing sides of four sides of the
electrode assembly formed in a rectangular cross-sectional
shape.
8. The lithium rechargeable battery of claim 1, wherein the
quantity of the positive electrode lead and the quantity of the
negative electrode lead are equal.
9. The lithium rechargeable battery of claim 1, wherein the
quantity of the positive electrode lead and the quantity of the
negative electrode lead are different.
10. The lithium rechargeable battery of claim 9, wherein the
quantity of the negative electrode lead is smaller than that of the
positive electrode lead.
11. The lithium rechargeable battery of claim 1, wherein a width of
the positive electrode lead and the negative electrode lead is in a
range of 1 to 10 cm.
12. The lithium rechargeable battery of claim 1, wherein a
thickness of the positive electrode lead and the negative electrode
lead is in a range of 50 to 500 .mu.m.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 13/054,974, filed Jan. 20, 2011, which is a
continuation of International Application No. PCT/KR2010009129,
filed Dec. 20, 2010, the disclosures of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a lithium rechargeable
battery, and more particularly, to a lithium rechargeable battery
having a multidirectional lead-tab structure.
[0004] 2. Related Art
[0005] A rechargeable battery is classified according to a
structure form of an electrode assembly having a positive
electrode/separator/negative electrode structure and includes a
jelly-roll (winding type) electrode assembly of a structure in
which long sheet type positive electrodes and negative electrodes
are wound with a separator interposed therebetween, a stack type
electrode assembly of a structure in which a plurality of positive
electrodes and negative electrodes cut in a predetermined size are
sequentially stacked with a separator interposed therebetween, and
a stack/folding type electrode assembly of a structure that winds
bi-cells or full cells in which a predetermined unit of positive
electrodes and negative electrodes are stacked with a separator
interposed therebetween.
[0006] Nowadays, interest has increased in a pouch type battery of
a structure in which a stack type electrode assembly or a
stack/folding type electrode assembly is housed in a pouch type
battery case of an aluminum laminate sheet due to a low production
cost, a small weight, and easy form modification, and use of the
pouch type battery gradually increases.
[0007] FIG. 1 is an exploded perspective view illustrating a
conventional typical pouch type rechargeable battery.
[0008] Referring to FIG. 1, a pouch type rechargeable battery 10
includes an electrode assembly 30, electrode tabs 31 and 32
extended from the electrode assembly 30, electrode leads 40 and 41
welded to the electrode tabs 31 and 32, and a battery case 20 for
housing the electrode assembly 30.
[0009] The electrode assembly 30 is a power generation element in
which a positive electrode and a negative electrode are
sequentially stacked with a separator interposed therebetween and
is formed in a stack type structure or a stack/folding type
structure. The electrode tabs 31 and 32 are extended from each
electrode plate of the electrode assembly 30, and the electrode
leads 40 and 41 are electrically connected by, for example, welding
to a plurality of electrode tabs 31 and 32, respectively, extended
from each electrode plate, and a part thereof is exposed to the
outside of the battery case 20. Further, in order to secure an
electrical insulation state while increasing a sealing degree with
the battery case 20, an insulation film 50 is attached to a part of
an upper surface and a lower surface of the electrode leads 40 and
41.
[0010] The battery case 20 includes a case body 22 including a
concave shape of reception portion 23 for receiving the electrode
assembly 30 and a cover 21 that is integrally connected to the case
body 22, and in a state where the electrode assembly 30 is received
in the reception portion 23, by bonding an upper end portion 25 and
a both side portion 24, which are contact portions, a battery is
complete. Because the battery case 20 is formed in an aluminum
laminate structure of a resin layer/metal thin layer/resin layer,
by applying a heat and a pressure to the upper end portion 25 and
the both side portion 24 of the contacting cover 21 and case body
22, a resin layer is fused and bonds them. Because the same resin
layer of the upper and lower battery case 20 directly contacts, the
both side portion 24 can be uniformly sealed by melting. However,
because the electrode leads 40 and 41 are protruded from the upper
end portion 25, in order to improve a sealing property in
consideration of a thickness of the electrode leads 40 and 41 and a
material of the electrode leads 40 and 41 different from that of
the battery case 20, by performing thermal fusion with an
insulation film 50 interposed between the electrode leads 40 and
41, a battery is finally manufactured.
[0011] FIG. 2 is an example of another pouch type battery and is a
perspective view illustrating a pouch type battery in which an
electrode lead is protruded from each of an upper part and a lower
part of a battery case.
[0012] A pouch type battery 101 of FIG. 2 is different from the
pouch type battery of FIG. 1 in that electrode leads 411 and 421
are positioned at an upper part and a lower part, respectively and
a battery case is separated as a lower case 221 and an upper case
231. Therefore, in the battery case, the lower case 221 and the
upper case 231 are bonded by thermo-compression and an upper
sealing portion 241, a lower sealing portion 261, and both side
surface sealing portions 251 and 271 are formed. A reception
portion 211 may be formed only in the upper case 231 or the lower
case 221, or in both the upper case 231 and the lower case 221.
[0013] As shown in FIGS. 1 and 2, in a conventional battery, after
electrode plates are stacked so that tabs of the same polarity are
aligned at the same position in an axial direction, by welding tabs
of the same polarity with one positive electrode or one negative
electrode, a battery is manufactured.
[0014] A battery manufactured in this way may be used as a battery
of a small capacity use, but when a battery manufactured in this
way is used as a medium and large battery use using a large
current, a problem may occur. That is, when the battery is used for
use requiring much energy, such as a vehicle, as a magnitude of a
current passing through a lead increases, much heat generates and
thus a problem may occur from a safety point of view.
[0015] In order to solve such a problem, a method of increasing a
thickness or a width of a lead-tab may be used, but in this case, a
sealing property of a lead-tab portion may be not good and thus a
problem that moisture penetrates into the portion may occur.
Further, because a lead and a tab having no standard size are used
in a mass production process, difficulty may arise in a production
process.
[0016] Therefore, a demand for a battery appropriate for using a
high current even while using a conventional lead-tab size has been
increased.
SUMMARY OF THE INVENTION
[0017] The present invention has been made in view of the above
problems, and provides a battery manufactured by alternately
stacking electrode plates so that tabs of electrode plates of the
same form have different directions and by welding the electrode
plate with a lead.
[0018] In accordance with an aspect of the present invention
provides a lithium rechargeable battery including: an electrode
assembly in which a separator and an electrode plate having a
current collector, an active material, and a tab are alternately
stacked; a lead electrically connected to the tab; and a battery
case, wherein the lead is divided into a positive electrode lead
and a negative electrode lead, and at least one positive electrode
lead and at least one negative electrode lead are provided.
[0019] In accordance with another aspect of the present invention
provides a lithium rechargeable battery including: an electrode
assembly in which a separator and an electrode plate having a
current collector, an active material, and a tab are alternately
stacked; a lead electrically connected to the tab; and a battery
case, wherein the lead is divided into a positive electrode lead
and a negative electrode lead, and at least two positive electrode
leads and at least two negative electrode leads are provided.
[0020] The electrode assembly may be formed by alternately stacking
electrode plates and separators so that tabs of electrode plates of
the same polarity have different axial direction positions, and the
lead may be provided at a position corresponding to the tab
position.
[0021] The electrode assembly may be formed by alternately stacking
electrode plates and separators so that tabs of electrode plates of
different polarity have different axial direction positions, and
the leads may be provided at positions corresponding to the tab
positions.
[0022] The electrode assembly may have a rectangular
cross-sectional shape, and the positive electrode lead and the
negative electrode lead may be each selectively provided at four
sides of the electrode assembly.
[0023] The positive electrode lead and the negative electrode lead
may be formed in the same direction at one side of four sides of
the electrode assembly formed in a rectangular cross-sectional
shape, the positive electrode lead and the negative electrode lead
may be each dividedly formed at adjacent sides of four sides of the
electrode assembly formed in a rectangular cross-sectional shape,
or the positive electrode lead and the negative electrode lead may
be each formed opposite to two opposing sides of four sides of the
electrode assembly formed in a rectangular cross-sectional
shape.
[0024] The quantity of the positive electrode lead and the quantity
of the negative electrode lead may be equal or different, and if
the quantity of the positive electrode lead and the quantity of the
negative electrode lead is different, the quantity of the negative
electrode lead may be smaller than that of the positive electrode
lead.
[0025] A width of the positive electrode lead and the negative
electrode lead may be in a range of 1 to 10 cm.
[0026] A thickness of the positive electrode lead and the negative
electrode lead may be in a range of 50 to 500 .mu.m.
[0027] The lithium rechargeable battery may be used for a large
area battery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The objects, features and advantages of the present
invention will be more apparent from the following detailed
description in conjunction with the accompanying drawings, in
which:
[0029] FIGS. 1 and 2 are perspective views illustrating a
conventional typical pouch type rechargeable battery;
[0030] FIGS. 3 and 4 are schematic diagrams illustrating a
rechargeable battery according to an exemplary embodiment of the
present invention;
[0031] FIGS. 5 and 6 are diagrams illustrating a method of stacking
an electrode plate;
[0032] FIG. 7 is a perspective view illustrating an electrode
assembly in which electrode plates are stacked according to an
exemplary embodiment of the present invention;
[0033] FIG. 8 is a schematic diagram illustrating an electrode
assembly in which electrode plates are stacked according to another
exemplary embodiment of the present invention;
[0034] FIG. 9 is a diagram illustrating a structure of an electrode
assembly according to an exemplary embodiment of the present
invention;
[0035] FIG. 10 is a diagram illustrating a structure of an
electrode assembly according to another exemplary embodiment of the
present invention; and
[0036] FIGS. 11 to 14 are schematic diagrams illustrating electrode
leads formed in several directions of an electrode assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Hereinafter, a lithium rechargeable battery according to
exemplary embodiments of the present invention will be described in
detail with reference to the accompanying drawings. The exemplary
embodiments should be considered in descriptive sense only and not
for purposes of limitation. Therefore, the scope of the invention
is defined not by the detailed description of the invention but by
the appended claims.
[0038] FIGS. 3 and 4 are schematic diagrams illustrating a
rechargeable battery according to an exemplary embodiment of the
present invention.
[0039] The present invention provides a lithium rechargeable
battery including an electrode assembly in which a separator and an
electrode plate having a current collector, an active material, and
a tab are alternately stacked; a lead electrically connected to the
tab; and a battery case, wherein the lead is divided into a
positive electrode lead and a negative electrode lead, and at least
two positive electrode leads and at least two negative electrode
leads are provided.
[0040] That is, the present invention is characterized in that at
least two positive electrode leads and at least two negative
electrode leads are provided, unlike conventional technology in
which a positive electrode lead and a negative electrode lead are
provided. This is to distribute a current by providing two or more
leads instead of providing one lead, unlike conventional
technology.
[0041] In this case, the electrode assembly is formed by
alternately stacking electrode plates and separators so that tabs
of electrode plates of the same polarity have different axial
direction positions, and leads are provided at positions
corresponding to the tab positions. A meaning that axial direction
positions of tabs are different is that positions of tabs are
different when viewed in an axial direction.
[0042] As shown in FIG. 1, conventionally, by stacking electrode
plates so that tabs of electrode plates of the same polarity have
the same axial direction positions, an electrode assembly is
formed, but the present invention is characterized in that
electrode plates are alternately stacked so that tabs of identical
electrode plates have at least two axial direction positions. By
stacking the electrode plates in this way, the electrode plate is
easily welded with at least two positive electrode leads and at
least two negative electrode leads.
[0043] In an electrode assembly formed in a rectangular
cross-sectional shape, the electrode lead may be selectively
provided at four sides of the electrode assembly, as needed. For
example, FIG. 3 shows that two positive electrode leads and two
negative electrode leads are formed at each of two short sides of
four sides, and FIG. 4 shows that two positive electrode leads and
two negative electrode leads are formed at each of two long sides
of four sides.
[0044] In an exemplary embodiment described in relation to FIGS. 3
and 4, two positive electrode leads and two negative electrode
leads are formed, but the present invention is not limited thereto
and three or more positive electrode leads and three or more
negative electrode leads may be formed.
[0045] Particularly, it is preferable that a width a of the
positive electrode lead and the negative electrode lead used in the
present exemplary embodiment is in a range of 1 to 10 cm and a
thickness b of the positive electrode lead and the negative
electrode lead is in a range of 50 to 500 .mu.m.
[0046] If the width a and the thickness b is less than the range, a
magnitude of a current passing through the lead increases and thus
heat generation increases, whereby it is not preferable from safety
point of view. Particularly, in a large area battery requiring much
energy, the above-described problem may occur. Here, the large area
battery is a battery in which an area of an electrode assembly is
largely manufactured in order to charge and discharge much energy
and is generally a battery manufactured in a size of about 225
cm.sup.2 or more).
[0047] If the width a and the thickness b is greater than the
range, a sealing property of a lead-tab portion may not be good and
thus a moisture penetration problem may occur in the portion.
Further, because the width a and the thickness b deviate from a
size of a lead manufactured by punching, difficulty may arise in a
manufacturing process.
[0048] FIGS. 5 to 7 are diagrams schematically illustrating a
process of forming an electrode assembly according to an exemplary
embodiment of the present invention.
[0049] FIG. 5 illustrates a stacking concept of an electrode
assembly according to an exemplary embodiment of the present
invention.
[0050] As shown in FIG. 5, when identical electrode plates are
sequentially alternately stacked so that tabs of identical
electrode plates have different axial direction positions, tabs of
identical electrode plates may have at least two different axial
direction positions. By welding the tab to each of the positive
electrode lead and the negative electrode lead, a battery is
formed.
[0051] In this case, the positive electrode lead and the negative
electrode lead may be formed in the same direction at one side of
four sides of an electrode assembly formed in a rectangular
cross-sectional shape, as shown in an upper drawing of FIG. 5, or
may be dividedly formed at adjacent sides, as shown in a lower
drawing of FIG. 5. Although not shown, a positive electrode lead
and a negative electrode lead may be formed opposite at each of two
opposing sides of four sides of the electrode assembly.
[0052] FIG. 6 illustrates a process of manufacturing a battery
according to an exemplary embodiment of the present invention.
[0053] As shown in FIG. 6, the electrode assembly is formed by
alternately stacking electrode plates and separators so that tabs
of electrode plates of different polarity have different axial
direction positions, and leads are provided at positions
corresponding to the tab positions.
[0054] Thereby, a positive electrode plate and a negative electrode
plate in which an axial direction position of a tab is right-biased
are prepared, a separator is interposed therebetween, and then by
stacking them, a first stacking body is formed.
[0055] Thereafter, a positive electrode plate and a negative
electrode plate in which an axial direction position of a tab is
left-biased are prepared (in a positive electrode plate and a
negative electrode plate in which an active material is applied at
both side surfaces of a current collector, when the right-biased
positive electrode plate and negative electrode plate are inverted,
a left-biased positive electrode plate and negative electrode plate
may be formed), a separator is interposed therebetween, and then by
stacking them, a second stacking body is formed.
[0056] After a separator is interposed between the first stacking
body and the second stacking body, by repeating a method of
stacking them, an electrode assembly in which axial direction
positions of tabs are different is finally complete, as shown in
FIG. 7.
[0057] Further, when a positive electrode tab and a negative
electrode tab are provided in the same direction at one side of
four sides of an electrode plate, another electrode plate in which
axial direction positions of tabs are different is prepared and
then by stacking electrode plates so that axial direction positions
of tabs are different, an electrode assembly may be complete, as
shown in FIG. 8.
[0058] In this case, a positive electrode tab and a negative
electrode tab are formed in the same direction at one side of four
sides of the electrode assembly, and a positive electrode tab and a
negative electrode tab are formed at the same position or are
formed at an alternate position at a side opposite to the one
side.
[0059] FIGS. 9 and 10 illustrate a structure of a battery
manufactured according to an exemplary embodiment of the present
invention.
[0060] Referring to FIG. 9, unlike a conventional electrode
assembly, by welding leads provided at positions corresponding to
each tab to electrode assemblies stacked so that tabs of identical
electrode plates have different axial direction positions, a
positive electrode lead and a negative electrode lead are dividedly
formed at each of opposing sides of four sides of the electrode
assembly, and thus a battery is complete.
[0061] Referring to FIG. 10, the electrode assemblies are stacked
so that axial direction positions of tabs of the electrode assembly
are positioned, as shown in a lower drawing of FIG. 5, and by
welding the tab with a corresponding electrode lead, a positive
electrode lead is formed at two adjacent sides of four sides of the
electrode assembly and a negative electrode lead is formed at the
remaining two sides and thus a battery having a structure of FIG.
10 is complete.
[0062] In the foregoing exemplary embodiment, an electrode assembly
in which the quantity of positive electrode leads and the quantity
of negative electrode leads are at least two and are equal is
exemplified, but it is unnecessary that the quantity of positive
electrode leads and the quantity of negative electrode leads are at
least two and are equal. When the quantity of positive electrode
leads and the quantity of negative electrode leads are at least two
within an allowable range of a battery, a distribution effect of a
current can be more excellent.
[0063] In general, a positive electrode plate uses an aluminum foil
and a negative electrode plate uses a copper foil, and electrical
conductivity of copper is two or more times greater than that of
aluminum and thus the quantity of positive electrode leads and the
quantity of negative electrode leads may be not equal.
[0064] Therefore, the present invention provides a lithium
rechargeable battery including an electrode assembly in which a
separator and an electrode plate having a current collector, an
active material, and a tab are alternately stacked; a lead
electrically connected to the tab; and a battery case, wherein the
lead is divided into a positive electrode lead and a negative
electrode lead, and at least one positive electrode lead and at
least one negative electrode lead are provided.
[0065] Such an example is shown in FIGS. 11 to 14.
[0066] In FIGS. 11 and 12, leads are provided at each of short
sides of the electrode plate, three positive electrodes are formed
at a short side of one side of the electrode plate and two negative
electrodes are formed at the other side thereof, and in FIG. 12,
two positive electrode are formed at a short side of one side of
the electrode plate and one negative electrode is formed at the
other side thereof.
[0067] Further, in FIGS. 13 and 14, leads are provided at each of
long sides of the electrode plate, in FIG. 13, three positive
electrodes are formed at a long side of one side of the electrode
plate and two negative electrodes are formed at the other side
thereof, and in FIG. 14, two positive electrode are formed at a
long side of one side of the electrode plate and one negative
electrode is formed at the other side thereof.
[0068] In this way, the positive electrode lead and the negative
electrode lead may be formed with different quantities and as
described above, because copper used as a negative electrode plate
has electrical conductivity greater than that of aluminum used as a
positive electrode plate, even if the quantity of the negative
electrode lead is less than that of the positive electrode lead,
there is no problem in exhibiting a function of a rechargeable
battery.
[0069] In the present invention, a case where a length or a size of
a positive electrode lead and a negative electrode lead is equal is
exemplified, but the present invention is not limited thereto and a
length or a size of a positive electrode lead and a negative
electrode lead may be different.
[0070] As described above, according to the present invention, a
battery is manufactured by alternately stacking electrode plates so
that tabs of electrode plates of the same form have different
directions and by welding the electrode plates with leads and is
appropriate for using a high current even while using a
conventional lead-tab size.
[0071] Although exemplary embodiments of the present invention have
been described in detail hereinabove, it should be clearly
understood that many variations and modifications of the basic
inventive concepts herein described, which may appear to those
skilled in the art, will still fall within the spirit and scope of
the exemplary embodiments of the present invention as defined in
the appended claims.
* * * * *