JP-7856541-B2 - Energy storage module

JP7856541B2JP 7856541 B2JP7856541 B2JP 7856541B2JP-7856541-B2

Inventors

小村慎吾
山下裕介

Assignees

トヨタ自動車株式会社
株式会社豊田自動織機

Dates

Publication Date: 20260511
Application Date: 20221006

Claims (5)

Multiple bipolar electrodes stacked on top of each other, The outermost positive electrode is positioned on one of the outermost sides of the plurality of bipolar electrodes in the stacking direction of the plurality of bipolar electrodes, The outermost negative electrode is positioned on the other side of the plurality of bipolar electrodes in the stacking direction, A first sealing portion seals the first outer region, which is formed between the outermost positive electrode and the bipolar electrode facing the outermost positive electrode among the plurality of bipolar electrodes, when the pressure of the first outer region is lower than atmospheric pressure. A second sealing portion seals the second outer region, which is formed between the outermost negative electrode and the bipolar electrode facing the outermost negative electrode among the plurality of bipolar electrodes, when the pressure of the second outer region is lower than atmospheric pressure. An inner sealing portion that seals the inner region formed between a pair of bipolar electrodes adjacent to each other in the stacking direction when the pressure of the inner region is lower than atmospheric pressure, A first insulating member that insulates the outermost positive electrode from the bipolar electrode among the plurality of bipolar electrodes that faces the outermost positive electrode, A second insulating member that insulates the outermost negative electrode from the bipolar electrode among the plurality of bipolar electrodes that faces the outermost negative electrode, It comprises an inner insulating member that insulates between a pair of bipolar electrodes adjacent to each other 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 outermost positive electrode is, Positive electrode current collector foil, The positive electrode current collector foil has a positive electrode active material layer provided on it, The outermost negative electrode is, Negative electrode current collector foil, The negative electrode current collector foil has a negative electrode active material layer provided on it, In each of the current collectors, the peripheral edge of the positive electrode current collector foil and the peripheral edge of the positive electrode current collector foil in the outermost positive electrode have an uncoated positive electrode portion where the positive electrode active material layer is not provided. In each of the current collectors, the peripheral edge of the negative electrode current collector foil and the peripheral edge of the negative electrode current collector foil in the outermost negative electrode have a negative electrode uncoated portion that faces the positive electrode uncoated portion in the lamination direction and where the negative electrode active material layer is not provided. The region between the uncoated portion of the positive electrode and the uncoated portion of the negative electrode facing the uncoated portion of the positive electrode constitutes the first outer region. The region between the uncoated portion of the outermost negative electrode and the uncoated portion of the positive electrode facing the uncoated portion of the negative electrode constitutes the second outer region. The region between the uncoated positive electrode portion and the uncoated negative electrode portion of a pair of adjacent bipolar electrodes that face each other in the stacking direction constitutes the inner region. The first insulating member includes a first outer insulating portion arranged in the first outer region, The second insulating member includes a second outer insulating portion arranged in the second outer region, The inner insulating member includes an inner insulating portion arranged in the inner region, A power storage module in which the thickness of the first outer insulating portion and the thickness of the second outer insulating portion are greater than the thickness of the inner insulating portion.
The first insulating member includes a first separator disposed between the outermost positive electrode and the bipolar electrode among the plurality of bipolar electrodes that faces the outermost positive electrode. The first separator is, A first intervening portion is interposed between the positive electrode active material layer in the outermost positive electrode and the negative electrode active material layer in the bipolar electrode, It has a first peripheral portion connected to the first intervening portion and positioned in the first outer region, The first outer insulating portion is, The first peripheral portion and, It comprises a first insulating film, which is made of a separate component from the first separator and is arranged in the first outer region, The second insulating member is disposed between the outermost negative electrode and the bipolar electrode among the plurality of bipolar electrodes that faces the outermost negative electrode, and includes a second separator having the same thickness as the first separator. The second separator is, A second intervening portion is interposed between the negative electrode active material layer in the outermost negative electrode and the positive electrode active material layer in the bipolar electrode, It has a second peripheral portion connected to the second intervening portion and located in the second outer region, The second outer insulating portion is, The second peripheral portion and, The second insulating film, which is made of a separate component from the second separator and is arranged in the second outer region, The inner insulating member is arranged between a pair of bipolar electrodes adjacent to each other in the stacking direction and includes an inner separator having the same thickness as the first separator. The inner separator comprises an inner intervening portion interposed between the positive electrode active material layer and the negative electrode active material layer in the bipolar electrode, It has an inner peripheral portion that is connected to the inner intervening portion and is located in the inner region, The energy storage module according to claim 1, wherein the inner insulating portion is composed of the inner peripheral portion.
The first insulating film is positioned inside the first peripheral edge in the stacking direction within the first outer region, The energy storage module according to claim 2, wherein the second insulating film is disposed inside the second peripheral portion in the stacking direction of the second outer region.
The first insulating film is made of the same material as the material constituting the first sealing portion and is integrally formed with the first sealing portion. The energy storage module according to claim 3, wherein the second insulating film is made of the same material as the material constituting the second sealing portion and is integrally formed with the second sealing portion.
The first insulating member includes a first separator disposed between the outermost positive electrode and the bipolar electrode among the plurality of bipolar electrodes that faces the outermost positive electrode. The first separator is, A first intervening portion is interposed between the positive electrode active material layer in the outermost positive electrode and the negative electrode active material layer in the bipolar electrode, It has a first peripheral portion connected to the first intervening portion and positioned in the first outer region, The first outer insulating portion is composed of the first peripheral portion, The second insulating member is disposed between the outermost negative electrode and the bipolar electrode among the plurality of bipolar electrodes that faces the outermost negative electrode, and includes a second separator having the same thickness as the first separator. The second separator is, A second intervening portion is interposed between the negative electrode active material layer in the outermost negative electrode and the positive electrode active material layer in the bipolar electrode, It has a second peripheral portion connected to the second intervening portion and located in the second outer region, The second outer insulating portion is composed of the second peripheral portion, The inner insulating member is arranged between a pair of bipolar electrodes adjacent to each other in the stacking direction and includes an inner separator having a thickness smaller than the thickness of the first separator. The inner separator comprises an inner intervening portion interposed between the positive electrode active material layer and the negative electrode active material layer in the bipolar electrode, It has an inner peripheral portion that is connected to the inner intervening portion and is located in the inner region, The energy storage module according to claim 1, wherein the inner insulating portion is composed of the inner peripheral portion.

Description

This disclosure relates to energy storage modules. Japanese Patent Publication No. 2021-128898 discloses an energy storage module comprising a plurality of bipolar electrodes, a plurality of separators arranged between adjacent bipolar electrodes, a sealing portion that seals the space formed between adjacent bipolar electrodes, and an electrolyte solution arranged in that space. When viewed from the stacking direction, the separator has an overlapping portion that overlaps with the electrode layer of the bipolar electrode and an exposed portion that does not overlap with the electrode layer. The region where the exposed portion exists has the function of containing gas generated during charging and discharging. Japanese Patent Publication No. 2021-128898 This is a schematic cross-sectional view showing a storage module in the first embodiment of the present disclosure.This is a cross-sectional view that schematically shows the state in which each region is under reduced pressure.This is a schematic cross-sectional view showing a storage module in a second embodiment of the present disclosure.This table shows examples, comparative examples, and their evaluation results. Embodiments of this disclosure will be described with reference to the drawings. In the drawings referenced below, identical or equivalent components are given the same number. (First Embodiment) Figure 1 is a schematic cross-sectional view showing a power storage module in a first embodiment of the present disclosure. As shown in Figure 1, the power storage module 1 includes a plurality of bipolar electrodes 100, an outermost positive electrode 200, an outermost negative electrode 300, a first sealing portion 410, a second sealing portion 420, an inner sealing portion 430, a first insulating member 500, a second insulating member 600, and an inner insulating member 710. Multiple bipolar electrodes 100 are stacked on top of each other. Each bipolar electrode 100 has a current collector 110, a positive electrode active material layer 120, and a negative electrode active material layer 130. 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 111 and a negative electrode current collector foil 112. The positive electrode current collector foil 111 is made of, for example, aluminum. The negative electrode current collector foil 112 is made of, for example, copper foil. The negative electrode current collector foil 112 is bonded to the positive electrode current collector foil 111 by a conductive adhesive. The positive electrode active material layer 120 is provided on one surface of the current collector 110, i.e., on the surface of the positive electrode current collector foil 111. The negative electrode active material layer 130 is provided on the other surface of the current collector 110, i.e., on the surface of the negative electrode current collector foil 112. Multiple bipolar electrodes 100 are arranged such that the positive electrode active material layer 120 of one bipolar electrode 100 and the negative electrode active material layer 130 of a bipolar electrode 100 adjacent to the first bipolar electrode 100 face each other. The periphery of the positive electrode current collector foil 111 has an uncoated positive electrode portion 111a where the positive electrode active material layer 120 is not provided. The periphery of the negative electrode active material layer 130 has an uncoated negative electrode portion 112a where the negative electrode active material layer 130 is not provided. The uncoated negative electrode portion 112a faces the uncoated positive electrode portion 111a in the stacking direction of the multiple bipolar electrodes 100 (the vertical direction in Figure 1). The outermost positive electrode 200 is positioned on one of the outermost bipolar electrodes 100 in the stacking direction. The outermost positive electrode 200 comprises a positive electrode current collector foil 111 and a positive electrode active material layer 120 provided on the positive electrode current collector foil 111. The configuration of the positive electrode current collector foil 111 and the positive electrode active material layer 120 in the outermost positive electrode 200 is the same as that in the bipolar electrode 100. The outermost negative electrode 300 is positioned on the other side of the multiple bipolar electrodes 100 in the stacking direction. The outermost negative electrode 300 comprises a negative electrode current collector foil 112 and a negative electrode active material layer 130 provided on the negative electrode current collector foil 112. The configuration of the negative electrode current collector foil 112 and the negative electrode active material layer 130 in the outermost negative electrode 300 is the same as that of the bipolar electrode 100. The first sealing portion 410 seals the first outer