U.S. patent application number 12/722953 was filed with the patent office on 2010-12-09 for bi-polar rechargeable electrochemical battery.
This patent application is currently assigned to G4 SYNERGETICS, INC.. Invention is credited to Eileen Higgins, Martin Patrick Higgins, Randy Ogg, Steven J. Winick.
Application Number | 20100310923 12/722953 |
Document ID | / |
Family ID | 37075172 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100310923 |
Kind Code |
A1 |
Ogg; Randy ; et al. |
December 9, 2010 |
BI-POLAR RECHARGEABLE ELECTROCHEMICAL BATTERY
Abstract
A bi-polar battery has a positive electrode unit, a negative
electrode unit, at least one bi-polar electrode unit stacked
therebetween, an electrolyte layer separating each adjacent
electrode unit, and a gasket positioned about each electrolyte
layer for creating a seal about the electrolyte layer in
conjunction with the electrode units adjacent thereto. The bi-polar
battery also includes a wrapper for maintaining the seals created
by the gaskets.
Inventors: |
Ogg; Randy; (Newberry,
FL) ; Higgins; Martin Patrick; (Old Field, NY)
; Winick; Steven J.; (Woodmere, NY) ; Higgins;
Eileen; (Old Field, NY) |
Correspondence
Address: |
ROPES & GRAY LLP
PATENT DOCKETING 39/361, 1211 AVENUE OF THE AMERICAS
NEW YORK
NY
10036-8704
US
|
Assignee: |
G4 SYNERGETICS, INC.
Roslyn
NY
|
Family ID: |
37075172 |
Appl. No.: |
12/722953 |
Filed: |
March 12, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11417489 |
May 3, 2006 |
7794877 |
|
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12722953 |
|
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60677512 |
May 3, 2005 |
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Current U.S.
Class: |
429/162 ;
29/623.2; 429/210 |
Current CPC
Class: |
H01M 10/0477 20130101;
H01M 10/0413 20130101; Y10T 29/4911 20150115; H01M 10/0468
20130101; H01M 50/183 20210101; Y02E 60/10 20130101; H01M 10/345
20130101; H01M 10/0418 20130101; H01M 10/0486 20130101 |
Class at
Publication: |
429/162 ;
29/623.2; 429/210 |
International
Class: |
H01M 6/12 20060101
H01M006/12; H01M 4/82 20060101 H01M004/82 |
Claims
1-2. (canceled)
3. A method of manufacturing a battery, the method comprising:
providing a first electrode unit; providing a first electrolyte
layer on top of the first electrode unit in a stacking direction;
providing a first gasket on top of the first electrode unit and
about the first electrolyte layer; providing a second electrode
unit on top of the first electrolyte layer and first gasket in the
stacking direction; and sealing the first gasket to the first
electrode unit and the second electrode unit.
4. The method of claim 3, wherein the providing the first electrode
unit comprises: providing a first electrode layer with a first side
and a second side; providing a first active material on the first
side of the first electrode layer; and providing a first groove in
the first side of the first electrode layer about at least a
portion of the first active material.
5. The method of claim 4, wherein the providing the first gasket
comprised: providing a first gasket body portion with a top surface
and a bottom surface; providing a top groove in the top surface of
the first gasket body portion; and stacking the first gasket on top
of the first electrode unit, the first groove mating with the top
groove to align the first gasket with the first electrode unit.
6. The method of claim 5, further comprising: providing a wrapper
about the first and second electrode units; and compressing the
wrapper, wherein the wrapper exerts a first holding force on the
first and second electrode units in a first holding direction,
wherein the first holding direction is substantially perpendicular
to the stacking direction, and wherein the holding force pushes at
least a portion of the top groove against at least a portion of the
first groove in the first holding direction.
7. The method of claim 5, further comprising: providing a wrapper
about the first and second electrode units; and compressing the
wrapper, wherein the wrapper exerts a first holding force on the
first and second electrode units in a first holding direction,
wherein the first holding direction is substantially parallel to
the stacking direction, and wherein the holding force pushes at
least a portion of the top groove against at least a portion of the
first groove in the first holding direction.
8. The method of claim 3, wherein a cross-sectional area of the
first groove is one of rectangular, triangular, and curved.
9. The method of claim 3, wherein the first groove is continuous
about the entire first active material.
10. A battery comprising: a stack of a plurality of electrode units
in a stacking direction, the stack comprising: a first electrode
unit; a second electrode unit stacked on top of the first electrode
unit in the stacking direction; and a first electrolyte layer
provided between the first electrode unit and the second electrode
unit, the battery further comprising: a first gasket positioned
about the first electrolyte layer, wherein the first electrolyte
layer is sealed by the first gasket and the first and second
electrode units.
11. The battery of claim 10, wherein the first electrode unit is a
bi-polar electrode unit, and wherein the second electrode unit is a
bi-polar electrode unit.
12. The battery of claim 10, wherein the first electrode unit is a
mono-polar electrode unit, and wherein the second electrode unit is
a bi-polar electrode unit.
13. The battery of claim 10, wherein the first electrode unit
comprises: a first electrode layer having a first side and a second
side; and a first active material on the first side of the first
electrode layer, wherein the first electrode layer has a first
groove in the first side about at least a portion of the first
active material.
14. The battery of claim 13, wherein the first gasket comprises a
body portion having a top surface and a bottom surface, wherein the
body portion has a top groove in the top surface, and wherein the
first groove mates with the top groove to seal the first
electrolyte layer.
15. The battery of claim 14, wherein: at least a portion of the
first gasket extends along at least a portion of an edge of the
first electrode layer between the first side and the second side of
the first electrode layer.
16. The battery of claim 14, further comprising: a wrapper provided
about the stack, wherein the wrapper is compressible to exert a
first holding force on the stack in a first holding direction
substantially perpendicular to the stacking direction.
17. The battery of claim 16, wherein the holding force pushes at
least a portion of the top groove against at least a portion of the
first groove in the first holding direction.
18. The battery of claim 16, wherein the wrapper is compressible to
exert a second holding force on the stack in a second holding
direction substantially parallel to the stacking direction.
19. The battery of claim 18, wherein the holding force pushes at
least a portion of the top groove against at least a portion of the
first groove in the second holding direction.
20. The battery of claim 13, wherein a cross-sectional area of the
first groove is rectangular.
21. The battery of claim 13, wherein a cross-sectional area of the
first groove is triangular.
22. The battery of claim 13, wherein a cross-sectional area of the
first groove is curved.
23. The battery of claim 13, wherein the first groove is continuous
about the entire first active material.
24. The battery of claim 13, wherein the first groove is at least
partially smooth about the at least a portion of the first active
material.
25. The battery of claim 13, wherein the first groove is at least
partially jagged about the at least a portion of the first active
material.
26. The battery of claim 13, wherein the second electrode unit
comprises: a second electrode layer having a first side and a
second side; and a second active material on the second side of the
second electrode layer, wherein the second electrode layer has a
second groove in the second side about at least a portion of the
second active material.
27. The battery of claim 26, wherein the first gasket comprises a
body portion having a top surface and a bottom surface, wherein the
body portion has a top groove in the top surface and a bottom
groove in the bottom surface, and wherein the top groove mates with
the first groove and the bottom groove mates with the second groove
to seal the first electrolyte layer.
28. The battery of claim 27, wherein the first electrode unit is a
bi-polar electrode unit, and wherein the second electrode unit is a
bi-polar electrode unit.
29. The battery of claim 27, wherein the first electrode unit is a
mono-polar electrode unit, and wherein the second electrode unit is
a bi-polar electrode unit.
30. The battery of claim 10, wherein the first gasket is a solid
seal loop.
31. The battery of claim 10, wherein the first gasket is a viscous
paste.
32. The battery of claim 10, wherein the first gasket is
compressible.
33. The battery of claim 10, further comprising: a viscous paste
provided between the first gasket and at least one of the first
electrode unit and the second electrode unit.
34. The battery of claim 10, wherein the first electrode unit
comprises: a first electrode substrate having a first side and a
second side; and a first active layer on the first side of the
first electrode substrate, wherein the first active layer includes
at least a first active portion on a first portion of the first
side and a second active portion on a second portion of the first
side.
35. The battery of claim 34, wherein the first active portion
comprises at least a first active material, wherein the second
positive portion comprises at least a second active material, and
wherein the first active material is different than the second
active material.
36. The battery of claim 34, wherein the first active portion
extends a first height from the first side of the first electrode
substrate, wherein the second active portion extends a second
height from the first side of the first electrode substrate, and
wherein the first height is different than the second height.
37. The battery of claim 34, wherein the second electrode unit
comprises: a second electrode substrate having a first side and a
second side; a first active layer on the first side of the second
electrode substrate; and a second active layer on the second side
of the second electrode substrate.
38. The battery of claim 37, wherein the first electrode substrate
of the first electrode unit has a first thickness, wherein the
second electrode substrate of the second electrode unit has a
second thickness, and wherein the first thickness is different than
the second thickness.
39. The battery of claim 37, wherein the first electrode substrate
comprises at least a first material, wherein the second electrode
substrate comprises at least a second material, and wherein the
first material is different than the second material.
40. The battery of claim 37, wherein the first active layer on the
first side of the first electrode substrate is a positive active
layer and comprises at least a first positive active material,
wherein the first active layer on the first side of the second
electrode substrate is a positive active layer and comprises at
least a second positive active material, and wherein the first
positive active material is different than the second positive
active material.
41. The battery of claim 37, wherein the first active layer on the
first side of the first electrode substrate is a negative active
layer and comprises at least a first negative active material,
wherein the first active layer on the first side of the second
electrode substrate is a negative active layer and comprises at
least a second negative active material, and wherein the first
negative active material is different than the second negative
active material.
42. The battery of claim 10, wherein the stack further comprises: a
third electrode unit stacked on top of the second electrode unit in
the stacking direction; and a second electrolyte layer provided
between the second electrode unit and the third electrode unit,
wherein the battery further comprises: a second gasket positioned
about the second electrolyte layer, wherein the second electrolyte
layer is sealed by the second gasket and the second and third
electrode units.
43. The battery of claim 42, wherein the first gasket has a first
height in the stacking direction, wherein the second gasket has a
second height in the stacking direction, and wherein the first
height is different than the second height.
44. The battery of claim 42, wherein the first electrolyte layer
comprises at least a first chemical, wherein the second electrolyte
layer comprises at least a second chemical, and wherein the first
chemical and the second chemical are different.
45. The battery of claim 44, wherein the first electrolyte layer
has a first conductivity, wherein the second electrolyte layer has
a second conductivity, and wherein the first conductivity and the
second conductivity are different.
46. The battery of claim 42, wherein the first electrode unit is a
bi-polar electrode unit, wherein the second electrode unit is a
bi-polar electrode unit, and wherein the third electrode unit is a
bi-polar electrode unit.
47. The battery of claim 42, wherein the first electrode unit is a
mono-polar electrode unit, wherein the second electrode unit is a
bi-polar electrode unit, and wherein the third electrode unit is a
bi-polar electrode unit.
48. The battery of claim 42, wherein the first electrode unit is a
mono-polar electrode unit, wherein the second electrode unit is a
bi-polar electrode unit, and wherein the third electrode unit is a
mono-polar electrode unit.
49. The battery of claim 10, wherein the first electrolyte layer
comprises: an electrolyte material; and a barrier material that
electrically isolates the first and second electrode units.
50. The battery of claim 10: wherein the first electrode unit
comprises: a first bi-polar electrode layer, a first positive
active material on a first side of the first bi-polar electrode
layer, and a first negative active material on a second side of the
first bi-polar electrode layer; wherein the second bi-polar
electrode unit comprises: a second bi-polar electrode layer having
two sides, a second positive active material on a first side of the
second bi-polar electrode layer, and a second negative active
material on a second side of the second bi-polar electrode layer;
and wherein the first electrolyte layer comprises an electrolyte
material positioned between the first positive active material of
the first bi-polar electrode unit and the second negative active
material of the second bi-polar electrode unit.
Description
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/677,512, filed May 3, 2005, which is
hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to batteries and, more
particularly, to bi-polar batteries with improved sealing.
BACKGROUND OF THE INVENTION
[0003] Bi-polar batteries are able to provide an increased
discharge rate and a higher voltage potential between its external
connectors than standard wound or prismatic batteries, and are
therefore in high demand for certain applications. Conventional
batteries have been manufactured as either a wound cell battery
that has only two electrodes or a standard prismatic cell battery
that has many plate sets in parallel. In both of these types, the
electrolyte can be shared everywhere within the battery. The wound
cell and prismatic cell structures suffer from high electrical
resistances due to their electrical paths having to cross multiple
connections and cover significantly long distances to cover the
complete circuit from one cell to the next in a series
arrangement.
[0004] Recently, bi-polar batteries have been developed to
generally include a series of stacked bi-polar electrode units
(BPUs), each BPU being provided with a positive active material
electrode layer and a negative active material electrode layer
coated on opposite sides of a current collector (see, for example,
Fukuzawa et al. U.S. Patent Publication No. 2004/0161667 A1,
published Aug. 19, 2004, which is hereby incorporated by reference
herein in its entirety). Any two adjacent BPUs have an electrolyte
layer therebetween for electrically isolating the current
collectors of those two BPUs. The series configuration of a
bi-polar battery causes the voltage potential to be different
between current collectors. However, if the current collectors
contacted each other or if the common electrolyte of any two
adjacent BPUs is shared with any additional BPU, the voltage and
energy of the battery would fade (i.e., discharge) quickly to
zero.
[0005] Accordingly, it would be advantageous to be able to provide
a bi-polar battery with improved sealing of electrolyte between
adjacent BPUs.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of this invention to provide a
bi-polar battery with improved sealing of electrolyte between
adjacent bi-polar electrode units.
[0007] In accordance with the invention, there is provided a
bi-polar battery having a positive mono-polar electrode unit, a
negative mono-polar electrode unit, at least one bi-polar electrode
unit stacked between the positive electrode unit and the negative
electrode unit, and an electrolyte layer provided between each pair
of adjacent electrode units. The bi-polar battery also includes a
gasket positioned about each of the electrolyte layers, wherein
each of the electrolyte layers is sealed by its respective gasket
and its respective pair of adjacent electrode units.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The above and other advantages of the invention will be more
apparent upon consideration of the following detailed description,
taken in conjunction with the accompanying drawings, in which like
reference characters refer to like parts throughout, and in
which:
[0009] FIG. 1 is a schematic cross-sectional view of a basic
structure of a bi-polar electrode unit (BPU) according to the
invention;
[0010] FIG. 2 is a schematic cross-sectional view of a basic
structure of a stack of BPUs of FIG. 1 according to the
invention;
[0011] FIG. 3 is a schematic cross-sectional view of a basic
structure of a bi-polar battery implementing the stack of BPUs of
FIG. 2 according to the invention;
[0012] FIG. 4 is a schematic top view of the bi-polar battery of
FIG. 3, taken from line IV-IV of FIG. 3;
[0013] FIG. 4A is a schematic top view of the bi-polar battery of
FIG. 3, taken from line IVA-IVA of FIG. 3;
[0014] FIG. 5 is a schematic circuit diagram of the basic
constitution of the bi-polar battery of FIGS. 3-4A;
[0015] FIG. 6 is a detailed schematic cross-sectional view of a
particular portion of the bi-polar battery of FIGS. 3-5;
[0016] FIG. 7 is a schematic top view of the bi-polar battery of
FIGS. 3-6, taken from line VII-VII of FIG. 6;
[0017] FIG. 8 is a schematic top view of the bi-polar battery of
FIGS. 3-7, taken from line VIII-VIII of FIG. 6;
[0018] FIG. 9 is a schematic top view of the bi-polar battery of
FIGS. 3-8, taken from line IX-IX of FIG. 6;
[0019] FIG. 10 is a schematic cross-sectional view of certain
elements in a first stage of a method for forming a bi-polar
battery according to a preferred embodiment of the invention;
[0020] FIG. 11 is a schematic top view of the elements of FIG. 10,
taken from line XI-XI of FIG. 10;
[0021] FIG. 12 is a schematic cross-sectional view of certain
elements in a second stage of a method for forming a bi-polar
battery according to a preferred embodiment of the invention;
[0022] FIG. 13 is a schematic top view of the elements of FIG. 12,
taken from line XIII-XIII of FIG. 12;
[0023] FIG. 14 is a schematic cross-sectional view of certain
elements in a third stage of a method for forming a bi-polar
battery according to a preferred embodiment of the invention;
[0024] FIG. 15 is a schematic top view of the elements of FIG. 14,
taken from line XV-XV of FIG. 14;
[0025] FIG. 16 is a schematic cross-sectional view of certain
elements in a fourth stage of a method for forming a bi-polar
battery according to a preferred embodiment of the invention;
[0026] FIG. 17 is a schematic top view of the elements of FIG. 16,
taken from line XVII-XVII of FIG. 16;
[0027] FIG. 18 is a schematic cross-sectional view of certain
elements in a fifth stage of a method for forming a bi-polar
battery according to a preferred embodiment of the invention;
[0028] FIG. 19 is a schematic cross-sectional view of certain
elements in a sixth stage of a method for forming a bi-polar
battery according to a preferred embodiment of the invention;
[0029] FIG. 20 is a schematic top view of the elements of FIG. 19,
taken from line XX-XX of FIG. 19;
[0030] FIG. 21 is a schematic cross-sectional view of certain
elements in a sixth stage of a method for forming a bi-polar
battery according to an alternative embodiment of the
invention;
[0031] FIG. 22 is a schematic top view of the elements of FIG. 21,
taken from line XXII-XXII of FIG. 21;
[0032] FIG. 23 is a schematic top view of a bi-polar battery
according to an alternative embodiment of the invention; and
[0033] FIG. 24 is a schematic cross-sectional view of the bi-polar
battery of FIG. 23, taken from line XXIV-XXIV of FIG. 23.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The invention provides a bi-polar battery having a positive
mono-polar unit (MPU) terminal, a negative MPU terminal, and at
least one bi-polar unit (BPU) arranged substantially vertically
therebetween. Each BTU includes an electrode layer (e.g., a
conductive substrate) having two sides. A positive active material
is formed or positioned on the first side of the electrode layer,
and a negative material is formed or positioned on the second side
of the electrode layer. The bi-polar battery of this invention also
includes an electrolyte layer having an electrolyte between each
adjacent electrode unit (i.e., between each MPU and adjacent BPU,
and between each BPU and adjacent BPU) and a barrier that
electrically isolates the adjacent electrode units between which
the electrolyte layer is positioned. Additionally, the bi-polar
battery of this invention includes a gasket positioned
substantially about each electrolyte layer for sealing the
electrolyte of the electrolyte layer between the gasket and the two
electrode layers adjacent thereto.
[0035] The invention will now be described with reference to FIGS.
1-24.
[0036] FIG. 1 shows an illustrative BPU 2, in accordance with one
embodiment of the present invention, including a positive active
material electrode layer 4 provided on a first side of an
impermeable conductive substrate 6, and a negative active material
electrode layer 8 provided on the other side of the impermeable
conductive substrate 6.
[0037] As shown in FIG. 2, multiple BPUs 2 may be stacked
substantially vertically into a stack 20, with an electrolyte layer
10 provided between two adjacent BPUs 2, such that a positive
electrode layer 4 of one BPU 2 is opposed to a negative electrode
layer 8 of an adjacent BPU 2 via an electrolyte layer 10. Each
electrolyte layer 10 preferably includes a separator 9 that holds
an electrolyte 11 (see, e.g., FIG. 6). Separator 9 may electrically
separate the positive electrode layer 4 and negative electrode
layer 8 adjacent thereto, while allowing ionic transfer between the
electrode units for recombination, as described in more detail
below.
[0038] With continued reference to the stacked state of BPUs 2 in
FIG. 2, the components included in positive electrode layer 4 and
substrate 6 of a first BPU 2, the negative electrode layer 8 and
substrate 6 of a second BPU 2 adjacent to the first BPU 2, and the
electrolyte layer 10 between the first and second BPUs 2 shall be
referred to herein as a "cell segment" 22. Each impermeable
substrate 6 of each cell segment 22 is shared by the applicable
adjacent cell segment 22.
[0039] As shown in FIGS. 3 and 4, positive and negative terminals
may be provided along with stack 20 of one or more BPUs 2 to
constitute a bi-polar battery 50 in accordance with one embodiment
of the invention. A positive MPU 12, including a positive active
material electrode layer 14 provided on one side of an impermeable
conductive substrate 16, may be positioned at a first end of stack
20 with an electrolyte layer provided therebetween (i.e.,
electrolyte layer 10e), such that positive electrode layer 14 of
positive MPU 12 is opposed to a negative electrode layer (i.e.,
layer 8d) of the BPU (i.e., BPU 2d) at that first end of stack 20
via the electrolyte layer 10e. A negative MPU 32, including a
negative active material electrode layer 38 provided on one side of
an impermeable conductive substrate 36, may be positioned at the
second end of stack 20 with an electrolyte layer provided
therebetween (i.e., electrolyte layer 10a), such that negative
electrode layer 38 of negative MPU 32 is opposed to a positive
electrode layer (i.e., layer 4a) of the BPU (i.e., BPU 2a) at that
second end of stack 20 via the electrolyte layer 10a. If desired,
MPUs 12 and 32 may be provided with corresponding positive and
negative electrode leads 13 and 33, respectively.
[0040] It should be noted that the substrate and electrode layer of
each MPU may form a cell segment 22 with the substrate and
electrode layer of its adjacent BPU 2, and the electrolyte layer 10
therebetween, as shown in FIG. 3. The number of stacked BPUs 2 in
stack 20 may be one or more, and is appropriately determined in
order to correspond to a desired voltage for battery 50. Each BPU 2
may provide any desired potential, such that a desired voltage for
battery 50 may be achieved by effectively adding the potentials
provided by each component BPU 2. It will be understood that each
BPU 2 need not provide identical potentials.
[0041] In one suitable embodiment, bi-polar battery 50 is
structured so that the whole of the BPU stack 20 and its respective
positive and negative MPUs 12 and 32 is encapsulated (e.g.,
hermetically sealed) into a battery case or wrapper 40 under
reduced pressure. MPU conductive substrates 6 and 36 (or at least
their respective electrode leads 13 and 33) may be drawn out of
battery case 40, so as to mitigate impacts from the exterior upon
usage and to prevent environmental degradation. Indentations 42 may
be provided in MPUs 12 and 32 for a low-profile casing and a flat
surface.
[0042] In order to prevent electrolyte of a first cell segment 22
(see, e.g., electrolyte 11a of cell segment 22a of FIG. 6A) from
combining with the electrolyte of another cell segment 22 (see,
e.g., electrolyte 11b of cell segment 22b of FIG. 6A), gaskets are
preferably stacked with electrolyte layers 10 between adjacent
electrode units to seal electrolyte within its particular cell
segment 22. In one suitable arrangement, as shown in FIGS. 3-4A,
the bi-polar battery of the invention may include a gasket 60
positioned as a continuous loop about electrolyte layer 10 and
active material electrode layers 4, 8, 14, and 38 of each cell
segment 22 for sealing electrolyte between the gasket and the
electrode units of that segment (i.e., the BPUs or the SPU and MPU
adjacent to that gasket) and for keeping the appropriate gaps
between the adjacent conductive substrates 6/16/32 of that
segment.
[0043] As will be described in more detail below, in one suitable
approach, pressure may be applied to the top and bottom of case 40
in the direction of arrows P1 and P2 for compressing and holding
cell segments 22 and gaskets 60 in the sealed configuration shown
in FIGS. 3-4A. In another suitable approach, pressure may be
applied to the sides of case 40 in the direction of arrows P3 and
P4 for compressing and holding cell segments 22 and gaskets 60 in
the sealed configuration shown in FIGS. 3-4A. In yet another
suitable approach, pressure may be applied to the top and bottom of
case 40 in the direction of arrows P1 and P2 and pressure may be
also applied to the sides of case 40 in the direction of arrows P3
and P4 for compressing and holding cell segments 22 and gaskets 60
in the sealed configuration shown in FIGS. 3-4A. Such a bi-polar
battery 50 may include multiple cell segments 22 stacked and
series-connected, as shown in FIG. 5, to provide the desired
voltage.
[0044] Referring now to FIG. 6, there is shown an exploded view of
two particular cell segments 22 of battery 50 of the invention.
Cell segment 22a includes substrate 36 and negative electrode layer
38 of MPU 32, electrolyte layer 10a, as well as positive electrode
layer 4a and substrate 6a of BPU 2a. Cell segment 22b includes
substrate 6a and negative electrode layer 8a of BPU 2a, electrolyte
layer 10b, as well as positive electrode layer 4b and substrate 6b
of BPU 2b. As described above, each electrolyte layer 10 may
include a separator 9 and an electrolyte 11. A gasket 60 may be
provided as a continuous loop about electrolyte layer 10 of each
cell segment 22 such that separator 9 and electrolyte 11 of that
segment are completely sealed within the space defined by gasket 60
and the adjacent substrates of that particular cell segment.
[0045] As shown in FIGS. 6 and 7, gasket 60a surrounds electrolyte
layer 10a such that its separator 9a and electrolyte 11a are
completely sealed within the space defined by gasket 60a, substrate
36, and substrate 6a of cell segment 22a. Likewise, as shown in
FIGS. 6 and 8, gasket 60b surrounds electrolyte layer 10b such that
its separator 9b and electrolyte 11b are completely sealed within
the space defined by gasket 60b, substrate 6a, and substrate 6b of
cell segment 22b. Furthermore, each gasket may form a seal with the
active material layers of its cell segment by contacting their
sides (see, e.g., gasket 60a and the sides of active material
layers 38 and 4a).
[0046] In one suitable embodiment, in order to create a better
seal, the surface areas of the gasket and its adjacent substrates
that contact each other may be chamfered. As shown in FIGS. 6-9,
grooves 70 may be formed along the surface areas of the gaskets and
the substrates at their point of contact with one another, thereby
increasing the size of the contact area and creating a path of
greater resistance for any fluid attempting to break the seal
created between the gasket and substrate. The cross-sectional area
of groove 70 between the surfaces of the gasket and the particular
substrate may be of any suitable shape, such as sinusoidal (see,
e.g., groove 70a in FIG. 6), V-shaped (see, e.g., groove 70b in
FIG. 6), or rectangular (see, e.g., groove 70c in FIG. 6), for
example. Furthermore, the path of groove 70 about the particular
substrate of its cell segment may be of any suitable design, such
as smooth and continuous (see, e.g., groove 70a in FIG. 7), jagged
and continuous (see, e.g., groove 70b in FIG. 8), or non-continuous
(see, e.g., groove 70c of FIG. 9), for example. The shapes and
sizes of the grooves provided between gaskets and substrates
described herein are only exemplary, and any various sizes and
shapes may be used to create such grooves. Furthermore, no groove
may be provided between the gaskets and substrates in accordance
with certain embodiments of the present invention.
[0047] The substrates used to form the electrode units of the
invention (e.g., substrates 6, 16, and 36) may be formed of any
suitable conductive and impermeable material, such as a
non-perforated metal foil. The substrate of each BPU may typically
be between 1 and 5 millimeters thick, while the substrate of each
MPU may be between 5 and 10 millimeters thick and act as terminals
to the battery, for example. Each substrate may be made of aluminum
foil, stainless steel foil, cladding material comprising nickel and
aluminum, cladding material comprising copper and aluminum, nickel
plated steel, nickel plated copper, nickel plated aluminum, gold,
silver, or any suitable combination thereof, for example. Each
substrate may be made of two or more sheets of metal foils adhered
to one another, in certain embodiments.
[0048] The positive electrode layers provided on these substrates
to form the electrode units of the invention (e.g., positive
electrode layers 4 and 14) may be formed of any suitable active
material, such as nickel hydroxide (Ni(OH).sub.2), for example. The
positive active material may be sintered and impregnated, coated
with an aqueous binder and pressed, coated with an organic binder
and pressed, or contained by any other suitable method of
containing Ni(OH).sub.2 with other supporting chemicals in a
conductive matrix. The positive electrode layer of the electrode
unit may have metal hydride (MH) particles infused within the
Ni(OH).sub.2 matrix to reduce swelling, which increases cycle life,
to improve recombination, and to reduce pressure within the cell
segment. The MH may also be in a bonding of Ni(OH).sub.2 paste to
improve electrical conductivity within the electrode and to support
recombination. Other chemicals could be substituted for MH, such as
Pd or Ag, for example.
[0049] The negative electrode layers provided on these substrates
to form the electrode units of the invention (e.g., negative
electrode layers 8 and 38) may be formed of any suitable active
material, such as Metal hydride (MH), Cd, Zn, and Ag, for example.
The negative active material may be sintered; coated with an
aqueous binder and pressed, coated with an organic binder and
pressed, or contained by any other suitable method of containing MH
with other supporting chemicals in a conductive matrix. The MH
electrode side may have Ni(OH).sub.2 infused within the MH matrix
to stabilize the structure, reduce oxidation, and extend cycle
life. Other chemicals could be substituted for Ni(OH).sub.2, such
as Zn or Al, for example.
[0050] Various suitable binders, such as organic CMC binder,
Creyton rubber, and PTFE (Teflon), for example, may be mixed with
the active material layers to hold the layers to their
substrates.
[0051] The separator 9 of each electrolyte layer 10 of the bi-polar
battery of the invention may be formed of any suitable material
that electrically isolates its two adjacent electrode units while
allowing ionic transfer between those electrode units. The
separator may contain cellulose super absorbers to improve filling
and act as an electrolyte reservoir to increase cycle life, wherein
the separator may be made of a polyabsorb diaper material, for
example, whereby the separator could preferably release previously
absorbed electrolyte when charge is applied to the battery. In
certain embodiments, the separator may be of a lower density and
thicker than normal cells so that the Inter-Electrode-Spacing (IES)
can start higher than normal and be continually reduced to maintain
the C-rate and capacity of the battery over its life as well as to
extend the life of the battery.
[0052] The separator may be a thinner than normal material bonded
to the surface of the active material on the electrode units to
reduce shorting and improve recombination. This separator material
could be sprayed on, coated on, or pressed on, for example. The
separator may have a recombination agent attached thereto, in
certain embodiments. This agent could be infused within the
structure of the separator (this could be done by physically
trapping the agent in a wet process using a PVA to bind the agent
to the separator fibers, or the agent could be put therein by
electro-deposition, for example), or it could be layered on the
surface by vapor deposition. The material could be Pb, Ag, or any
other agent that effectively supports recombination. While the
separator preferably presents a resistance if the substrates move
toward each other, a separator may not be provided in certain
embodiments of the invention that utilize substrates that are stiff
enough not to deflect.
[0053] The electrolyte 11 of each electrolyte layer 10 of the
bi-polar battery of the invention may be formed of any suitable
chemical compound that ionizes when dissolved or molten to produce
an electrically conductive medium. The electrolyte is preferably a
standard NiMH electrolyte containing lithium hydroxide (LiOH),
sodium hydroxide (NaOH), calcium hydroxide (CaOH), or potassium
hydroxide (KOH), for example. The electrolyte may also contain
additives to improve recombination, such as Ag(OH).sub.2, for
example. The electrolyte may also contain RbOH, for example, to
improve low temperature performance. In some embodiments of the
invention, the electrolyte (e.g., electrolyte 11) may be frozen
within the separator (e.g., separator 9) and then thawed after the
battery is completely assembled. This allows for particularly
viscous electrolytes to be inserted into the electrode unit stack
of the bi-polar battery before the gaskets have formed
substantially fluid tight seals with the substrates adjacent
thereto.
[0054] The gaskets 60 of the bi-polar battery of the invention may
be formed of any suitable material or combination of materials that
may effectively seal an electrolyte within the space defined by the
gasket and the substrates adjacent thereto. In certain embodiments,
the gasket could be formed from a solid seal loop, such as nylon,
polypropylene, cell guard, rubber, PVA, or any other nonconductive
material, or combination thereof, for example. This seal ring may
be compressible to improve sealing. The compression may preferably
be about 5%, but may be whatever elasticity is needed to insure a
good seal.
[0055] Alternatively, the gaskets may be formed from a viscous
paste, such as epoxy, brea tar, or KOH impervious glue, for
example. In yet other embodiments, the gaskets utilized in the
bi-polar battery of this invention may be formed by a combination
of a solid seal loop and a viscous paste used to improve sealing
between the gasket and the electrode unit substrates adjacent
thereto. Alternatively, the substrates themselves could be treated
with viscous pastes before the gaskets are stacked
therebetween.
[0056] As mentioned above, one benefit of utilizing a bi-polar
battery design is the increased discharge rate of the battery. This
increased discharge rate allows for the use of certain
less-corrosive electrolytes (e.g., by removing or reducing the KOH
component of the electrolyte) that otherwise might not be feasible
in prismatic or wound battery designs. This leeway provided by the
bi-polar design to use less-corrosive electrolytes allows for
certain epoxies (e.g., J-B Weld epoxy, for example, which has no
KOH electrolytes) to be utilized when forming a seal with the
gaskets that otherwise would be corroded by more-corrosive
electrolytes.
[0057] As described above, the top and bottom of each gasket may be
chamfered to fit against a reciprocal groove in its adjacent
substrate. Furthermore, each gasket may be shaped at its external
edge such that it fits over the outside edge of its adjacent
substrate when placed in the stack (see, e.g., gasket 60a with
respect to substrate 6a in FIGS. 6 and 8).
[0058] The case or wrapper 40 of the bi-polar battery of the
invention may be formed of any suitable nonconductive material that
seals to the terminal electrode units (i.e., MPUs 12 and 32) for
exposing their conductive electrode layers (i.e., layers 4 and 38)
or their associated leads (i.e., leads 13 and 33). The wrapper also
preferably supports and maintains the seals between the gaskets and
the electrode unit substrates adjacent thereto for isolating the
electrolytes within their respective cell segments. The wrapper
preferably gives the support required to these seals such that they
may resist expansion of the battery as the internal pressures in
the cell segments increase. The wrapper may be made of nylon or any
other polymer or elastic material, including reinforced composites,
or shrink wrap material, or of a ridged material, such as enamel
coated steel or any other metal, for example.
[0059] With continued reference to FIG. 3, bi-polar battery 50 of
the invention includes a plurality of cell segments (e.g., cell
segments 22a-22e) formed by MPUs 12 and 32, and the stack of BPUs
(e.g., BPUs 2a-2d) therebetween. In accordance with certain
embodiments of the invention, the thicknesses and materials of each
one of the substrates (e.g., substrates 6a-6d), the electrode
layers (e.g., positive layers 4a-d and 14, and negative layers
8a-8d and 38), the electrolyte layers (e.g., layers 10a-10e), and
the gaskets (e.g., gaskets 60a-60e) may differ from one another,
not only from cell segment to cell segment, but also within a
particular cell segment, thereby creating batteries with a plethora
of different benefits and performance characteristics.
[0060] For example, substrate 6a of BPU 2a may be coated with a
variety of active materials along different portions thereof for
forming positive active material electrode layer 4a, as shown, for
example, in FIG. 4A by outermost portion 4a', middle portion 4a'',
and innermost portion 4a'''. Each one of portions 4a'-4a''' may be
formed by a different active material and/or may be of a different
thickness, for example.
[0061] Additionally, besides varying the materials and thicknesses
within a particular substrate, electrode layer, electrolyte layer,
or gasket, as described above with respect to substrate 6a in FIG.
4A, the materials and thicknesses of the substrates, electrode
layers, electrolyte layers, and gaskets can vary along the height
of the stack of cell segments. As an example, the electrolyte used
in each of the electrolyte layers of battery 50 may vary based upon
how close its respective cell segment is to the middle of the stack
of cell segments. For example, cell segment 22c (i.e., the middle
cell segment of the five (5) segments 22 in battery 50) may include
an electrolyte layer (i.e., electrolyte layer 10c) that is formed
of a first electrolyte, while cell segments 22b and 22d (i.e., the
cell segments adjacent the terminal cell segments in battery 50)
may include electrolyte layers (i.e., electrolyte layers 10b and
10d, respectively) that are each formed of a second electrolyte,
while cell segments 22a and 22e (i.e., the outermost cell segments
in battery 50) may include electrolyte layers (i.e., electrolyte
layers 10a and 10e, respectively) that are each formed of a third
electrolyte. By using higher conductivity electrolytes in the
internal stacks, the resistance would be lower such that the heat
generated would be less, thereby providing the thermal control of
the battery by design instead of by external cooling methods.
[0062] As mentioned above, a method of producing the bi-polar
battery of this invention may generally include the steps of
providing an MPU and stacking one or more BPUs thereon with
electrolyte layers and gaskets therebetween, before finally topping
off the stack with another MPU of opposite polarity. For example,
with respect to FIGS. 10 and 11, a negative MPU 1032 may initially
be provided with an impermeable conductive substrate 1036 and a
negative active material electrode layer 1038 coated thereon.
Substrate 1036 is preferably provided with a groove 1070 at least
partially about negative layer 1038.
[0063] Next, a gasket 1060 is preferably stacked upon substrate
1036 about electrode layer 1038 (see, e.g., FIGS. 12 and 13). A
groove 1061 is preferably chamfered into the side of gasket 1060
that contacts substrate 1036, such that grooves 1070 and 1061 align
to create a continuous contact surface area between the gasket and
the substrate. These reciprocal grooves aid in the self-alignment
of the gasket with respect to the MPU as it is stacked thereupon,
thereby simplifying this production step. Once gasket 1060 has been
stacked firmly on top of MPU 1032, a substantially fluid tight
cup-shaped receptacle (see, e.g., space 1080) is thus defined by
the inner side walls of gasket 1060 and the portions of MPU 1032
therebetween. The angle formed between the inner side walls of the
gasket and the portions of the electrode unit therebetween (e.g.,
angle 1078 between the inner side walls of gasket 1060 and the
portions of MPU 1032 therebetween in FIG. 13) may be of any
suitable angle, including right angles, obtuse angles, or acute
angles.
[0064] Next, a separator 1009 and an electrolyte 1011 may be
deposited within the inner walls of gasket 1060 on top of negative
electrode layer 1038 to define an electrolyte layer 1010 within the
space 1080 (see, e.g., FIGS. 14 and 15). When the electrolyte to be
used is quite viscous, the seal created between the gasket and the
MPU allows for the electrolyte to be easily injected into space
1080 without chance of leaking. It is to be understood that if the
electrolyte is not viscous upon insertion into the stack (e.g., in
the embodiment where the electrolyte is frozen within the
separator), the electrolyte layer may be stacked upon the MPU
before the gasket is fitted thereon.
[0065] Once separator 1009 and electrolyte 1011 of electrolyte
layer 1010 have been deposited within space 1080 defined by gasket
1060 and MPU 1032, a first BPU 1102 may be stacked thereupon (see,
e.g., FIGS. 16 and 17). As shown in FIG. 16, BPU 1102 includes an
impermeable conductive substrate 1106 having a positive electrode
layer 1104 and a negative electrode layer 1108 coated on opposite
sides thereof. Substrate 1106 is preferably provided with a groove
1172 on one of its sides at least partially about positive
electrode layer 1104. With positive electrode layer 1104 of BPU
1102 facing downwards towards negative electrode layer 1038 of MPU
1032, BPU 1102 is stacked upon gasket 1060, such that groove 1062
provided on the top of gasket 1060 and groove 1172 of substrate
1106 align and create a continuous contact surface area between the
gasket and the substrate. These reciprocal grooves aid in the
self-alignment of the BPU with respect to the gasket, and therefore
the MPU as it is stacked thereupon, thereby simplifying this
production step. Once BPU 1102 has been stacked firmly on top of
gasket 1060, and thus MPU 1032, a first cell segment 1022 exists.
Moreover, a substantially fluid tight seal is thereby defined by
substrate 1106, substrate 1036, and gasket 1060 about electrolyte
layer 1010 (and thus electrolyte 1011).
[0066] It should be noted that, while groove 1062 on the top of
gasket 1060 (and thus groove 1172 on the bottom of substrate 1106)
may be of the same size, shape, and form (both cross-sectionally
and about the electrodes) as that of groove 1061 on the bottom of
gasket 1060, the grooves on the top and bottom of the gasket may be
different from one another, as shown in FIG. 16, for example.
Similarly, the grooves provided on the top and bottom of each
substrate of the electrode units may vary with respect to one
another (see, e.g., grooves 1172 and 1170 of BPU 1102 in FIG.
16).
[0067] Once this first cell segment 1022 has been created by
stacking gasket 1060, electrolyte layer 1010, and BPU 1102 on top
of MPU 1032, as described above with respect to FIGS. 10-17,
additional BPUs may be stacked thereon in a similar fashion, if
desired. Once the desired amount of BPUs has been stacked for the
bi-polar battery, a second MPU must be stacked thereon. With
reference to FIG. 18, a positive MPU 1012 may be stacked on top of
the top most BPU (in this embodiment, only one BPU has been
provided, so BPU 1102 is that top most BPU). However, before MPU
1012 is stacked upon BPU 1102, an additional gasket (i.e., gasket
1160 with bottom groove 1161 and top groove 1162) and electrolyte
layer (i.e., electrolyte layer 1110 with separator 1109 and
electrolyte 1111) may be provided as described above with respect
to gasket 1060 and electrolyte layer 1010.
[0068] Positive MPU 1012 is preferably provided with an impermeable
conductive substrate 1016 and a positive active material electrode
layer 1014 coated thereon. Substrate 1016 is preferably provided
with a groove 1072 at least partially about positive layer 1014.
With positive electrode layer 1014 of MPU 1012 facing downwards
towards negative electrode layer 1108 of BPU 1102, MPU 1012 is
stacked upon gasket 1160, such that groove 1162 provided on the top
of gasket 1160 and groove 1072 of substrate 1016 align and create a
continuous contact surface area between the gasket and the
substrate. These reciprocal grooves aid in the self-alignment of
positive MPU 1012 with respect to gasket 1160, and therefore BPU
1102, and therefore gasket 1060, and therefore negative MPU 1032 as
it is stacked thereupon. This self-aligning feature of the bi-polar
battery of the invention significantly simplifies this production
step. Once MPU 1012 has been stacked firmly on top of gasket 1160,
and thus BPU 1102, a second cell segment (i.e., segment 1122)
exists. Moreover, a substantially fluid tight seal is thereby
defined by substrate 1016, substrate 1106, and gasket 1160 about
electrolyte layer 1110 (and thus electrolyte 1111).
[0069] Once a stack is manufactured to include a positive MPU, a
negative MPU, at least one BPU therebetween, and a gasket and
electrolyte layer between each of the electrode units, thereby
forming a stack of cell segments, as described above with respect
to FIGS. 10-18, a case or wrapper may be provided to seal the
contents of the stack for forming a functional bi-polar battery of
the invention. In a first embodiment, as shown in FIGS. 19 and 20,
a preferably rigid wrapper 1040 is provided about the stack of cell
segments (i.e., cell segments 1022 and 1122), such that the
terminal electrode layers (i.e., positive electrode layer 1014 and
negative electrode layer 1038) are exposed (via conductive
substrates 1016 and 1036, respectively), and such that a C-shaped
clamping arrangement is provided by the wrapper about the contents
of the stack to provide a bi-polar battery 1050. Pressure is
exerted by the wrapper both downward onto substrate 1016 of MPU
1012 in the direction of arrows P.sub.D as well as upward onto
substrate 1036 of MPU 1032 in the direction of arrows P.sub.U. This
pressure preferably maintains the sealed relationship between each
gasket and the substrates adjacent thereto in the stack for
creating substantially fluid tight barriers about each electrolyte
layer. It should be noted that the mating of grooves formed in the
gaskets and their adjacent substrates, as described above in
accordance with certain embodiments of the invention, decreases the
amount of clamping pressure required to be exerted in the direction
of arrows P.sub.D and P.sub.U in order to create the substantially
fluid tight seals.
[0070] In another embodiment, as shown in FIGS. 21 and 22, a
wrapper 1040', preferably made of seal wrap, shrink wrap, seal
tape, or any other suitable deformable material, is provided about
the stack of cell segments (i.e., cell segments 1022 and 1122),
such that the terminal electrode layers (i.e., positive electrode
layer 1014 and negative electrode layer 1038) are exposed (via
conductive substrates 1016 and 1036, respectively), and such that a
solely outer-edge clamping arrangement is provided by wrapping the
wrapper about the contents of the stack to provide a bi-polar
battery 1050'. The stack of cell segments, as wrapped by wrapper
1040', is preferably placed inside a rigid container 1060' whose
cross-sectional area is similar in shape but somewhat larger than
that of the wrapped stack. Once the wrapped stack is placed inside
the rigid container 1060', any suitable fluid 1070' that expands
when under pressure, such as air, water, or foam, for example, is
filled into the container 1060' about the wrapper 1040'. The
container may then be sealed and its enclosed fluid 1070' may be
pressurized such that it expands to provide pressure inward about
the entire surface area of wrapper 1040' in the direction of arrows
P.sub.S for tightening wrapper 1040' about the stack of cell
segments. This pressure maintains the sealed relationship between
each gasket and the substrates adjacent thereto in the stack for
creating substantially fluid tight barriers about each electrolyte
layer of battery 1050', which may be subsequently removed from
container 1060'.
[0071] Although each of the above described and illustrated
embodiments of the bi-polar battery show a battery formed by
stacking substrates that are round into a cylindrical battery, it
should be noted that any of a wide variety of shapes may be
utilized to form the substrates of the bi-polar battery of the
invention. For example, the bi-polar battery of the invention may
be formed by stacking substrates with cross-sectional areas that
are rectangular, triangular, hexagonal, or any other imaginable
shape, including those with one or more empty spaces within a
plane, such as a "figure-8" (see, e.g., battery 2050, having
wrapper 2040', BPU 2102, and MPUs 2012 and 2032, in FIGS. 23 and
24), for example.
[0072] Thus, it is seen that a bi-polar battery has been provided
with a positive electrode unit, a negative electrode unit, at least
one bi-polar electrode unit stacked therebetween, an electrolyte
layer separating each adjacent electrode unit, and a gasket
positioned about each electrolyte layer for creating a seal about
the electrolyte layer in conjunction with the electrode units
adjacent thereto. It should be noted that the materials, shapes,
and sizes of the electrode units, electrolyte layers, and gaskets
described above are only exemplary. One skilled in the art will
appreciate that the invention can be practiced by other than the
described embodiments, which are presented for purposes of
illustration and not of limitation, and the invention is limited
only by the claims which follow.
* * * * *