Energy storage module

Abstract

To provide a power storage module capable of suppressing the decrease in volume of a gas pocket.SOLUTION: A power storage module 1 includes an electrode multilayer body 10 including a plurality of bipolar electrodes 100, a positive electrode terminal electrode 200, and a negative electrode terminal electrode 300, a sealing part 500, and a buffer region formation member 600 to form a closed buffer region R2. Each bipolar electrode 100 includes a current collector 110, a positive electrode active material layer 120, and a negative electrode active material layer 130. The positive electrode terminal electrode 200 includes a positive electrode current collector foil 112 and a positive electrode active material layer 120. The negative electrode terminal electrode 300 includes a negative electrode foil 113 and a negative electrode active material layer 130. The sealing part 500 seals a region R1 in a state where a region R1 formed between a positive electrode non-applied part 112b and a negative electrode non-applied part 113b has lower pressure than atmospheric pressure. The buffer region formation member 600 forms the buffer region R2 at a position overlapping with the region R1 in a lamination direction.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present disclosure relates to a power storage module.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2021-128898 discloses a power storage module including a plurality of bipolar electrodes, a plurality of separators disposed between adjacent bipolar electrodes, a sealing portion that seals a space formed between adjacent bipolar electrodes, and an electrolytic solution disposed in the space. The separator has an overlapping portion that overlaps an electrode layer in the bipolar electrode and an exposed portion that does not overlap the electrode layer when viewed from the stacking direction. The region where the exposed portion exists has a function of accommodating gas generated from the electrode during charge and discharge.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] A battery storage module according to one aspect of the present disclosure comprises an electrode stack including a plurality of bipolar electrodes stacked on top of each other, a positive terminal electrode disposed on one side of the plurality of bipolar electrodes in the stacking direction of the plurality of bipolar electrodes, and a negative terminal electrode disposed on the other side of the plurality of bipolar electrodes in the stacking direction, a sealing portion that seals between a pair of electrodes adjacent to each other in the stacking direction of the electrode stack, and a buffer area forming member that forms a sealed buffer area on the outside of the electrode stack in the stacking direction, wherein each of the plurality of bipolar electrodes has a current collector including a positive current collector foil and a negative current collector foil, a positive electrode active material layer provided on the positive current collector foil in the current collector, and a negative electrode active material layer provided on the negative current collector foil in the current collector, and the positive terminal electrode is The current collector has a positive electrode current collector foil and a positive electrode active material layer provided on the positive electrode current collector foil, the negative electrode terminal electrode has a negative electrode foil and a negative electrode active material layer provided on the negative electrode electrode foil, the positive electrode current collector foil in each current collector and the positive electrode current collector foil in the positive electrode terminal electrode has a positive electrode coated portion provided with the positive electrode active material layer and a positive electrode uncoated portion where the positive electrode active material layer is not provided, the negative electrode current collector foil in each current collector and the negative electrode current collector foil in the negative electrode terminal electrode has a negative electrode coated portion provided with the negative electrode active material layer and a negative electrode uncoated portion facing the positive electrode uncoated portion in the stacking direction and where the negative electrode active material layer is not provided, and the sealing portion seals the region formed between the positive electrode uncoated portion and the negative electrode uncoated portion when the pressure of the region is lower than atmospheric pressure, The buffer region forming member forms the buffer region at a position that overlaps with the region in the stacking direction. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide an energy storage module that can suppress the reduction in the volume of the gas pocket. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing the energy storage module in the first embodiment of this disclosure. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a schematic perspective view showing the energy storage module in the second embodiment of this disclosure. [Figure 4] Figure 3 shows a cross-sectional view along line IV-IV. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0011] (First Embodiment) Figure 1 is a schematic perspective view of a power storage module in a first embodiment of the present disclosure. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. As shown in Figures 1 and 2, the power storage module 1 comprises an electrode stack 10, a plurality of separators 400, a sealing portion 500, and a buffer zone forming member 600.

[0012] The electrode stack 10 includes a plurality of bipolar electrodes 100, a positive terminal electrode 200, and a negative terminal electrode 300.

[0013] Multiple bipolar electrodes 100 are stacked on top of each other. As shown in Figure 2, each bipolar electrode 100 has a current collector 110, a positive electrode active material layer 120, and a negative electrode active material layer 130.

[0014] The current collector 110 is made of metal and is formed, for example, in a rectangular shape. The current collector 110 has a positive electrode current collector foil 112 and a negative electrode current collector foil 113. The positive electrode current collector foil 112 is made of, for example, aluminum. The negative electrode current collector foil 113 is made of, for example, copper foil. The negative electrode current collector foil 113 is adhered to the positive electrode current collector foil 112 by a conductive adhesive.

[0015] The positive electrode active material layer 120 is provided on one surface of the current collector 110, that is, on the surface of the positive electrode current collector foil 112. The negative electrode active material layer 130 is provided on the other surface of the current collector 110, that is, on the surface of the negative electrode current collector foil 113.

[0016] A plurality of bipolar electrodes 100 are laminated such that the positive electrode active material layer 120 in one bipolar electrode 100 and the negative electrode active material layer 130 in the bipolar electrode 100 adjacent to the one bipolar electrode 100 face each other.

[0017] The positive electrode terminal electrode 200 is disposed on one side of the plurality of bipolar electrodes 100 in the stacking direction. The positive electrode terminal electrode 200 has a positive electrode current collector foil 112 and a positive electrode active material layer 120 provided on the positive electrode current collector foil 112. The configurations of the positive electrode current collector foil 112 and the positive electrode active material layer 120 in the positive electrode terminal electrode 200 are the same as those in the bipolar electrode 100.

[0018] The negative electrode terminal electrode 300 is disposed on the other side of the plurality of bipolar electrodes 100 in the stacking direction and has a negative electrode current collector foil 113 and a negative electrode active material layer 130 provided on the negative electrode current collector foil 113. The configurations of the negative electrode current collector foil 113 and the negative electrode active material layer 130 in the negative electrode terminal electrode 300 are the same as those in the bipolar electrode 100.

[0019] The positive electrode current collector foil 112 in each bipolar electrode 100 and the positive electrode current collector foil 112 in the positive electrode terminal electrode 200 have a positive electrode coated portion 112a and a positive electrode uncoated portion 112b.

[0020] The positive electrode coating part 112a is the part where the positive electrode active material layer 120 is provided.

[0021] The uncoated part 112b of the positive electrode is the part where the positive electrode active material layer 120 is not provided, that is, the part where the positive electrode current collector foil 112 is exposed.

[0022] The negative electrode current collector foil 113 in each bipolar electrode 100 and the negative electrode current collector foil 113 in the negative electrode terminal electrode 300 have a negative electrode coating part 113a and an uncoated part 113b of the negative electrode.

[0023] The negative electrode coating part 113a is the part where the negative electrode active material layer 130 is provided.

[0024] The uncoated part 113b of the negative electrode is the part where the negative electrode active material layer 130 is not provided, that is, the part where the negative electrode current collector foil 113 is exposed. The uncoated part 113b of the negative electrode faces the uncoated part 112b of the positive electrode in the stacking direction.

[0025] Each separator 400 is disposed between a pair of electrodes 100, 200, 300 adjacent to each other in the stacking direction. Specifically, each separator 400 is disposed between the positive electrode active material layer 120 and the negative electrode active material layer 130. Each separator 400 is made of an insulating material and allows the permeation of ions. Examples of each separator 400 include a polyolefin microporous membrane.

[0026] The sealing portion 500 is made of an insulating material (such as resin). The sealing portion 500 seals the space between pairs of electrodes 100, 200, and 300 that are adjacent to each other in the stacking direction within the electrode laminate 10. More specifically, the sealing portion 500 seals region R1 (see Figure 2) formed between the uncoated positive electrode portion 112b and the uncoated negative electrode portion 113b when the pressure of this region is lower than atmospheric pressure. An electrolyte is sealed in this region R1. The sealing portion 500 holds the peripheral edges of each current collector foil 112 and 113 and the peripheral edges of each separator 400. The sealing portion 500 has the function of preventing leakage of the electrolyte from region R1 and the intrusion of moisture into region R1 from the outside, and also has the function of ensuring the spacing between the uncoated positive electrode portion 112b and the uncoated negative electrode portion 113b, which are arranged to sandwich region R1. Region R1 functions as a gas pocket that contains the gas generated from electrodes 100, 200, and 300 during charging and discharging.

[0027] The buffer region forming member 600 forms a sealed buffer region R2 (see Figure 2) on the outside of the electrode laminate 10 in the stacking direction. As shown in Figure 2, the buffer region forming member 600 forms the buffer region R2 at a position overlapping with region R1 in the stacking direction. The buffer region forming member 600 includes a positive electrode side conductive member 612, a positive electrode side conductive film 622, a positive electrode side holding portion 632, a positive electrode side support portion 642, a negative electrode side conductive member 613, a negative electrode side conductive film 623, a negative electrode side holding portion 633, and a negative electrode side support portion 643.

[0028] The positive electrode side conductive member 612 is positioned so as to be in contact with the outer surface of the positive electrode coating portion 112a of the positive electrode terminal electrode 200. The positive electrode side conductive member 612 is formed in a flat plate shape. The positive electrode side conductive member 612 is made of aluminum, copper, or the like.

[0029] The positive electrode side conductive film 622 covers the positive electrode side conductive member 612. The film 622 covers the entire outer surface of the positive electrode side conductive member 612. The positive electrode side conductive film 622 is made of aluminum or the like.

[0030] The positive electrode side holding portion 632 holds the peripheral edge of the positive electrode side conductive film 622 so as to form a buffer region R2 together with the uncoated positive electrode portion 112b of the positive electrode terminal electrode 200, the positive electrode side conductive member 612, and the positive electrode side conductive film 622. The positive electrode side holding portion 632 is made of an insulating material (such as resin). The positive electrode side holding portion 632 is connected to the outer end surface of the sealing portion 500 in the lamination direction. The positive electrode side holding portion 632 may be made of the same material as the sealing portion 500, or it may be formed integrally with the sealing portion 500.

[0031] As shown in Figure 2, the portion of the positive electrode side conductive film 622 that defines the buffer region R2 (the portion between the positive electrode side conductive member 612 and the positive electrode side holding portion 632) is deformed inward in the lamination direction due to the differential pressure between atmospheric pressure and the pressure within region R1.

[0032] The positive electrode side support portion 642 is positioned between the uncoated positive electrode portion 112b of the positive electrode terminal electrode 200 and the positive electrode side conductive film 622. The positive electrode side support portion 642 supports the positive electrode side conductive film 622. The positive electrode side support portion 642 is made of an insulating material (such as resin). The positive electrode side support portion 642 has a shape that extends from the positive electrode side holding portion 632 toward the positive electrode side conductive member 612. The positive electrode side support portion 642 may be made of the same material as the positive electrode side holding portion 632, or it may be formed integrally with the positive electrode side holding portion 632. The positive electrode side support portion 642 is set to have a rigidity sufficient to support the positive electrode side conductive film 622 that is deformed inward in the lamination direction. The positive electrode side support portion 642 may be in contact with the uncoated positive electrode portion 112b of the positive electrode terminal electrode 200, or it may be spaced apart from the uncoated positive electrode portion 112b.

[0033] The negative electrode side conductive member 613, the negative electrode side conductive film 623, the negative electrode side holding part 633, and the negative electrode side support part 643 each have a configuration corresponding to the positive electrode side conductive member 612, the positive electrode side conductive film 622, the positive electrode side holding part 632, and the positive electrode side support part 642, respectively. Therefore, the explanation of the negative electrode side conductive member 613, the negative electrode side conductive film 623, the negative electrode side holding part 633, and the negative electrode side support part 643 will be simplified.

[0034] The negative electrode side conductive member 613 is positioned so as to be in contact with the outer surface of the negative electrode coating portion 113a of the negative electrode terminal electrode 300.

[0035] The negative electrode side conductive film 623 covers the negative electrode side conductive member 613.

[0036] The negative electrode side holding portion 633 holds the peripheral edge of the negative electrode side conductive film 623 so as to form a buffer region R2 together with the uncoated negative electrode portion 113b of the negative electrode terminal electrode 300, the negative electrode side conductive member 613, and the negative electrode side conductive film 623.

[0037] The negative electrode side support portion 643 is positioned between the uncoated negative electrode portion 113b of the negative electrode terminal electrode 300 and the negative electrode side conductive film 623. The negative electrode side support portion 643 supports the negative electrode side conductive film 623.

[0038] As described above, in the energy storage module 1 of this embodiment, a sealed buffer region R2 is formed at a position overlapping the stacking direction with a sealed region R1 that is at a pressure lower than atmospheric pressure. Since this buffer region R2 absorbs the pressure difference between atmospheric pressure and the pressure in region R1, the uncoated portions 112b and 113b of each terminal electrode 200 and 300 approach the uncoated portions 112b and 113b of the bipolar electrode 100 that are opposite to the uncoated portions 112b and 113b, that is, the reduction in the volume of the gas pocket is suppressed.

[0039] Furthermore, contact between the uncoated portions 112b and 113b of each terminal electrode 200 and 300 and the uncoated portions 112b and 113b of the bipolar electrode 100 facing the uncoated portions 112b and 113b (the occurrence of a short circuit) is suppressed.

[0040] (Second Embodiment) Next, the energy storage module 1 in the second embodiment of this disclosure will be described with reference to Figures 3 and 4. In the second embodiment, only the parts that differ from the first embodiment will be described, and the same descriptions of structure, operation, and effects as in the first embodiment will not be repeated.

[0041] In this embodiment, the buffer zone forming member 600 has a cover 650 and a sealing portion 660.

[0042] The cover 650 covers the sealing portion 500. The cover 650 is made of a so-called aluminum laminate film. Specifically, the cover 650 has an aluminum layer 651 and a resin layer 652 that covers the front and back surfaces of the aluminum layer 651. The cover 650 has an inner edge portion 654 that is formed in a position that overlaps with the positive electrode coating portion 112a and the negative electrode coating portion 113a in the lamination direction. In other words, the cover 650 covers the entire outer surface of the positive electrode uncoated portion 112b of the positive electrode terminal electrode 200 and the entire outer surface of the negative electrode uncoated portion 113b of the negative electrode terminal electrode 300.

[0043] The sealing portion 660 connects the cover 650 to the electrode stack 10. Specifically, the sealing portion 660 connects its inner edge 654 to the positive electrode coating portion 112a of the positive electrode terminal electrode 200 and the negative electrode coating portion 113a of the negative electrode terminal electrode 300.

[0044] Those skilled in the art will understand that the exemplary embodiments and examples described above are specific examples of the following embodiments.

[0045] [Aspect 1] An electrode laminate comprising a plurality of bipolar electrodes stacked on top of each other, a positive terminal electrode positioned on one side of the plurality of bipolar electrodes in the stacking direction of the plurality of bipolar electrodes, and a negative terminal electrode positioned on the other side of the plurality of bipolar electrodes in the stacking direction, The electrode stack includes a sealing portion that seals between a pair of electrodes adjacent to each other in the stacking direction, The system comprises a buffer zone forming member that forms a sealed buffer zone on the outside of the electrode stack in the stacking direction, Each of the aforementioned bipolar electrodes is A current collector including a positive electrode current collector foil and a negative electrode current collector foil, A positive electrode active material layer provided on the positive electrode current collector foil in the current collector, The current collector comprises a negative electrode active material layer provided on the negative electrode current collector foil, The positive terminal electrode is, Positive electrode current collector foil, The positive electrode current collector foil has a positive electrode active material layer provided on it, The aforementioned negative terminal electrode is, Negative electrode foil and The negative electrode foil has a negative electrode active material layer provided on it, The positive electrode current collector foil in each of the current collectors and the positive electrode current collector foil in the positive electrode terminal electrode are, The positive electrode coating portion provided with the positive electrode active material layer, The positive electrode has an uncoated portion where the positive electrode active material layer is not provided, The negative electrode current collector foil in each of the current collectors and the negative electrode current collector foil in the negative electrode terminal electrode are The negative electrode coating section provided with the negative electrode active material layer, It has a negative electrode uncoated portion that faces the positive electrode uncoated portion in the stacking direction and where the negative electrode active material layer is not provided, The sealing portion seals the region formed between the uncoated positive electrode portion and the uncoated negative electrode portion when the pressure in that region is lower than atmospheric pressure. The buffer region forming member forms the buffer region at a position overlapping with the region in the stacking direction, and is an energy storage module.

[0046] In this energy storage module, a sealed buffer zone is formed in a position that overlaps with the region sealed at a pressure lower than atmospheric pressure in the stacking direction. Because this buffer zone absorbs the pressure difference between atmospheric pressure and the pressure within the region, the uncoated portion of each terminal electrode approaches the uncoated portion of the bipolar electrode facing that uncoated portion, thus suppressing a decrease in the volume of the gas pocket.

[0047] [Aspect 2] The buffer zone forming member is A positive electrode side conductive member is arranged so as to be in contact with the outer surface of the positive electrode coating portion of the positive electrode terminal electrode, A positive electrode side conductive film covering the positive electrode side conductive member, A positive electrode side holding portion that holds the peripheral edge of the positive electrode side conductive film so as to form the buffer area together with the positive electrode uncoated portion of the positive electrode terminal electrode, the positive electrode side conductive member, and the positive electrode side conductive film, A negative electrode side conductive member is arranged so as to be in contact with the outer surface of the negative electrode coating portion of the negative electrode terminal electrode, A negative electrode side conductive film covering the negative electrode side conductive member, The energy storage module according to embodiment 1, further comprising: the uncoated negative electrode portion of the negative electrode terminal electrode; the negative electrode side conductive member; and a negative electrode side holding portion that holds the peripheral edge of the negative electrode side conductive film so as to form the buffer region together with the negative electrode side conductive film.

[0048] In this embodiment, the compressive force due to atmospheric pressure is absorbed by the inward deformation of the positive electrode conductive film and the negative electrode conductive film in the lamination direction. Therefore, the reduction in the volume of the gas pocket is effectively suppressed.

[0049] Furthermore, since the outer surface of the energy storage module in the stacking direction is composed of a positive electrode side conductive film and a negative electrode side conductive film, it is possible to stack multiple energy storage modules via conductive members (such as current collector plates).

[0050] [Aspect 3] A positive electrode side support portion is disposed between the uncoated portion of the positive electrode terminal electrode and the positive electrode side conductive film, and supports the positive electrode side conductive film. The energy storage module according to embodiment 2, further comprising: a negative electrode side support portion disposed between the uncoated negative electrode portion and the negative electrode side conductive film in the negative electrode terminal electrode, and supporting the negative electrode side conductive film.

[0051] In this embodiment, since each conductive film is supported by each support portion, the reduction in the volume of the gas pocket is more reliably suppressed.

[0052] [Aspect 4] The buffer zone forming member is A cover that covers the sealing portion, The cover has a sealing portion for connecting it to the electrode stack, The cover has an inner edge portion formed in a position that overlaps with the positive electrode coating portion and the negative electrode coating portion in the stacking direction. The energy storage module according to embodiment 1, wherein the sealing portion is connected to the electrode stack.

[0053] In this embodiment, the portion of the cover that overlaps with the region in the stacking direction deforms inward in the stacking direction, thereby absorbing the compressive force due to atmospheric pressure.

[0054] Furthermore, by placing conductive materials (such as current collector plates) on the parts of each terminal electrode that are not covered by a cover, it becomes possible to stack multiple energy storage modules.

[0055] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0056] 1 Energy storage module, 10 Electrode stack, 100 Bipolar electrode, 110 Current collector, 112 Positive electrode current collector foil, 112a Positive electrode coated section, 112b Positive electrode uncoated section, 113 Negative electrode current collector foil, 113a Negative electrode coated section, 113b Negative electrode uncoated section, 120 Positive electrode active material layer, 130 1. Negative electrode active material layer, 200 positive electrode termination electrode, 300 negative electrode termination electrode, 400 separator, 500 sealing part, 600 buffer zone forming member, 612 positive electrode side conductive member, 613 negative electrode side conductive member, 622 positive electrode side conductive film, 623 negative electrode side conductive film, 632 positive electrode side holding part, 633 negative electrode side holding part, 642 positive electrode side support part, 643 negative electrode side support part, 650 cover, 654 inner edge part, 660 seal part, R1 region, R2 buffer zone.

Claims

[Claim 1] An electrode laminate including multiple bipolar electrodes, a positive terminal electrode, and a negative terminal electrode, The electrode stack includes a sealing portion that seals the space between a pair of electrodes adjacent to each other in the stacking direction, The system comprises a buffer zone forming member that forms a sealed buffer zone on the outside of the electrode stack in the stacking direction, Each of the bipolar electrodes has a positive electrode current collector foil and a positive electrode terminal electrode has a positive electrode coated portion and a positive electrode uncoated portion. Each of the bipolar electrodes has a negative electrode current collector foil and a negative electrode terminal electrode has a negative electrode coated portion and a negative electrode uncoated portion. The sealing portion seals the region formed between the uncoated positive electrode portion and the uncoated negative electrode portion when the pressure in that region is lower than atmospheric pressure. The buffer region forming member has the buffer region formed at a position that overlaps with the region in the stacking direction, The buffer zone forming member is A conductive film provided on the outside of the electrode stack in the aforementioned stacking direction and outside the aforementioned region, A power storage module comprising at least one insulating member disposed in the buffer area.

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