Power storage device

Abstract

The capacitor (1) comprises an electrode stack (100) including a plurality of bipolar electrodes (110) and a pair of outermost current collectors (130), an internal voltage detection terminal (300), a housing (400), and a pair of external voltage detection terminals (700). Each of the plurality of bipolar electrodes (110) has a current collector (111), a positive electrode active material layer (112), and a negative electrode active material layer (113). The internal voltage detection terminal (300) is electrically connected to the current collector (111). Each of the pair of external voltage detection terminals (700) has a thickness greater than the thickness of the internal voltage detection terminal (300). The housing (400) is located between the pair of external voltage detection terminals (700) in the stacking direction. The dimension (T1) of the housing (400) in the stacking direction is less than or equal to the length (T3) between a pair of external voltage detection terminals (700) in the stacking direction.

Description

Technology Field

[0001] The present disclosure relates to a storage device. Background Technology

[0002] Japanese Patent Publication No. 2020-61221 discloses a bipolar battery having a plurality of bipolar electrodes and a voltage detection terminal connected to a current collector in each bipolar electrode. The problem to be solved

[0003] In the bipolar battery described in Japanese Patent Publication No. 2020-61221, the voltage detection terminal may be maintained in the housing, and in this case, if the voltage detection terminal is connected to the outermost cell in the stacking direction, the length of the housing in the stacking direction is increased. In this way, the energy storage device as a whole becomes larger.

[0004] The objective of the present disclosure is to provide a storage device capable of avoiding large size. means of solving the problem

[0005] A capacitor device according to one aspect of the present disclosure comprises: an electrode stack including a plurality of bipolar electrodes stacked together and a pair of outermost current collectors disposed on the outer side of the plurality of bipolar electrodes in the stacking direction of the plurality of bipolar electrodes; an internal voltage detection terminal connected to at least one of the plurality of bipolar electrodes; a housing holding at least one of the internal voltage detection terminals; and a pair of external voltage detection terminals electrically connected to each of the pair of outermost current collectors, wherein each of the plurality of bipolar electrodes has a current collector, a positive electrode active material layer formed on one side of the current collector, and a negative electrode active material layer formed on the other side of the current collector, wherein the internal voltage detection terminal is electrically connected to the bipolar electrode, and each of the pair of external voltage detection terminals has a thickness greater than the thickness of the at least one internal voltage detection terminal, and the housing is located between the pair of external voltage detection terminals in the stacking direction, and the dimensions of the housing in the stacking direction are such that in the stacking direction The length between the above pair of external voltage detection terminals is less than or equal to the length of the above pair.

[0006] The above and other objects, features, aspects, and advantages of the present invention will become apparent from the following detailed description of the invention as understood in conjunction with the accompanying drawings. Brief explanation of the drawing

[0007] FIG. 1 is a cross-sectional view schematically illustrating a capacitor device in one embodiment of the present disclosure. FIG. 2 is a plan view of an external current collector, an external voltage detection terminal, and an insulating member in a capacitor. Figure 3 is a cross-sectional view along line III-III in Figure 2. FIG. 4 is a plan view schematically showing a modified example of the insulation mode between an external current collector plate and an external voltage detection terminal. Figure 5 is a cross-sectional view along the VV line in Figure 4. FIG. 6 is a plan view schematically showing a modified example of the insulation mode between an external current collector plate and an external voltage detection terminal. FIG. 7 is a cross-sectional view along line VII-VII in FIG. 6. FIG. 8 is a plan view schematically showing a modified example of the insulation mode between an external current collector plate and an external voltage detection terminal. FIG. 9 is a cross-sectional view along the line IX-IX in FIG. 8. FIG. 10 is a plan view schematically showing a modified example of the insulation mode between an external current collector plate and an external voltage detection terminal. FIG. 11 is a cross-sectional view along the line XI-XI in FIG. 10. Specific details for implementing the invention

[0008] Embodiments of the present disclosure will be described with reference to the drawings. In addition, in the drawings referenced below, identical or equivalent components are given the same number.

[0009] FIG. 1 is a cross-sectional view schematically illustrating a capacitor device according to one embodiment of the present disclosure. As shown in FIG. 1, the capacitor device (1) comprises an electrode laminate (100), a sealing member (200), at least one internal voltage detection terminal (300), a housing (400), a pair of external current collector plates (500), a conductive adhesive (600), a pair of external voltage detection terminals (700), and an insulating member (800) (see FIG. 2).

[0010] The electrode laminate (100) has a plurality of bipolar electrodes (110), a plurality of separators (120), and a pair of outermost current collectors (130).

[0011] A plurality of bipolar electrodes (110) are stacked together. Each bipolar electrode (110) has a current collector (111), a positive electrode active material layer (112), and a negative electrode active material layer (113).

[0012] The current collector (111) is made of, for example, metal. The current collector (111) is formed in, for example, a rectangular shape.

[0013] The positive electrode active material layer (112) is formed on one side (the lower side in FIG. 1) of the current collector (111).

[0014] The negative electrode active material layer (113) is formed on the other side (upper side in FIG. 1) of the current collector (111).

[0015] A plurality of bipolar electrodes (110) are stacked such that a positive electrode active material layer (112) in one bipolar electrode (110) and a negative electrode active material layer (113) in a bipolar electrode (110) adjacent to the one bipolar electrode (110) face each other.

[0016] A separator (120) is disposed between a positive electrode active material layer (112) and a negative electrode active material layer (113). The separator (120) has the function of allowing ions to pass through while insulating both the positive electrode active material layer (112) and the negative electrode active material layer (113) so that they do not come into direct contact. The thickness of the separator (120) may be smaller than the thickness of the positive electrode active material layer (112) and the thickness of the negative electrode active material layer (113).

[0017] Each outermost current collector (130) is positioned on the outside of the plurality of bipolar electrodes (110) in the stacking direction (up and down direction in FIG. 1) of the plurality of bipolar electrodes (110). In one outermost current collector (130), only a positive electrode active material layer (112) is formed so as to face the negative electrode active material layer (113) of the bipolar electrode (110) adjacent to the outermost current collector (130) by interposing a separator (120), and in the other outermost current collector (130), only a negative electrode active material layer (113) is formed so as to face the positive electrode active material layer (112) of the bipolar electrode (110) adjacent to the outermost current collector (130) by interposing a separator (120).

[0018] A cell is formed by a pair of current collectors (111) adjacent to each other in the stacking direction, a positive electrode active material layer (112), a separator (120), and a negative electrode active material layer (113) disposed between the pair of current collectors (111). That is, the electrode stack (100) is composed of a plurality of cells stacked together, and the current collector on the outer side of the cell disposed on the outermost side in the stacking direction among the plurality of cells constitutes the outermost current collector (130).

[0019] In a bipolar battery formed by stacking multiple cells, each bipolar electrode (110) serves as both the positive and negative electrode of adjacent cells, and multiple cells are connected in series.

[0020] The encapsulating member (200) encapsulates the internal space formed between a pair of current collectors adjacent to each other in the stacking direction. The encapsulating member (200) is made of an insulating member. The encapsulating member (200) holds the respective ends of the current collector (111), the outermost current collector (130), and the separator (120) in a direction orthogonal to the stacking direction. In this embodiment, the internal space is filled with an electrolyte. However, each cell constituting the electrode stack (100) may be composed of a so-called all-solid-state battery having a solid electrolyte. In this case, the separator (120) is omitted.

[0021] An internal voltage detection terminal (300) is electrically connected to a bipolar electrode (110) disposed inside a pair of outermost current collectors (130) in the stacking direction. Specifically, the internal voltage detection terminal (300) is connected to a current collector (111) and is drawn out to the outside of the encapsulation member (200). In this embodiment, at least one internal voltage detection terminal (300) includes an equal number of internal voltage detection terminals (300) as the number of current collectors (111), and each internal voltage detection terminal (300) is connected to a current collector (111). However, the number of internal voltage detection terminals (300) may be less than the number of current collectors (111). In this case, the internal voltage detection terminals (300) are connected to a predetermined number of current collectors (111) arranged in the stacking direction at a ratio of one. That is, among the multiple current collectors (111) arranged in the stacking direction, there may be a current collector (111) to which the internal voltage detection terminal (300) is not connected. The internal voltage detection terminal (300) protrudes from the encapsulation member (200), for example, in a direction orthogonal to the stacking direction. The thickness of the internal voltage detection terminal (300) is approximately 0.05 mm to 0.1 mm. The internal voltage detection terminal (300) is connected to a detection circuit (not shown). Between the internal voltage detection terminals (300) adjacent to each other, the internal voltage detection terminals (300) are arranged offset in a direction orthogonal to the stacking direction.

[0022] The housing (400) holds the internal voltage detection terminal (300). The housing (400) is made of an insulating material. The housing (400) is fixed to the outer surface of the encapsulation member (200) in a direction orthogonal to the stacking direction. The size of the housing (400) is set to hold the internal voltage detection terminal (300). As shown in FIG. 1, the dimension (T1) of the housing (400) in the stacking direction is preferably set to be less than or equal to the length T2 of the encapsulation member (200) in the stacking direction. However, the dimension (T1) of the housing (400) in the stacking direction may be set to be less than or equal to the length (T3) between the outer surfaces of a pair of external voltage detection terminals (700) in the stacking direction.

[0023] Each external current collector plate (500) is positioned on the outside of the electrode stack (100) in the stacking direction. More specifically, each external current collector plate (500) is positioned on the outside of the outermost current collector (130) in the stacking direction. As shown in FIG. 2, each external current collector plate (500) is formed in a rectangular shape, for example. The thickness of each external current collector plate (500) is set to approximately 0.5 mm to 3 mm.

[0024] A conductive adhesive (600) is formed on the outer surface of the outermost current collector (130) in the lamination direction.

[0025] Each external voltage detection terminal (700) is electrically connected to the outermost current collector (130). More specifically, as shown in FIGS. 1 and 3, each external voltage detection terminal (700) is electrically connected to the outermost current collector (130) via a conductive adhesive (600). That is, the conductive adhesive (600) has a first adhesive portion (610) that is conductive and connects the outermost current collector (130) and the external current collector plate (500), and a second adhesive portion (620) that is conductive and connects the outermost current collector (130) and the external voltage detection terminal (700). Each external voltage detection terminal (700) is connected to a detection circuit (not shown).

[0026] The thickness of each external voltage detection terminal (700) may be the same as or different from the thickness of each external current collector plate (500). The thickness of each external voltage detection terminal (700) should be such that sufficient rigidity is ensured so that the external voltage detection terminal (700) does not bend under its own weight, for example, about 0.5 mm to 3 mm. The thickness of the external voltage detection terminal (700) is set to be, for example, less than or equal to the thickness of the external current collector plate (500). The outer surface of each external voltage detection terminal (700) in the stacking direction may be formed to be identical to the outer surface of each external current collector plate (500) in the stacking direction. By doing so, the length (T3) is avoided from becoming larger than the length between the outer surfaces of a pair of external current collector plates (500) in the stacking direction.

[0027] Each external voltage detection terminal (700) protrudes from the external current collector plate (500) in the same direction as the direction in which the internal voltage detection terminal (300) protrudes from the encapsulation member (200) (the right direction in FIG. 1 and FIG. 2). As shown in FIG. 2, the width of the external voltage detection terminal (700) in the direction orthogonal to both the direction in which the external voltage detection terminal (700) protrudes from the external current collector plate (500) and the stacking direction (the up-down direction in FIG. 2) is smaller than the width of the external current collector plate (500) in the same direction.

[0028] Each external voltage detection terminal (700) is located on the outside of the encapsulation member (200) in the stacking direction. Each external voltage detection terminal (700) is located on the outside of the housing (400) in the stacking direction.

[0029] An insulating member (800) is formed between an external voltage detection terminal (700) and an external current collector plate (500). The insulating member (800) insulates the external current collector plate (500) and the external voltage detection terminal (700). The insulating member (800) is formed by insert molding or by applying an insulating adhesive. In addition, in FIG. 2, a diagonal line is drawn on the insulating member (800).

[0030] As indicated by arrow AR1 in FIG. 3, a large current flows from the electrode laminate (100) toward the outer current collector plate (500) through the first adhesive portion (610), while the detection of the voltage of the outermost current collector (130) by the external voltage detection terminal (700) is made possible by the second adhesive portion (620) interposed between the external voltage detection terminal (700) and the outermost current collector (130). Additionally, current flow from the outer current collector plate (500) to the external voltage detection terminal (700) is blocked by an insulating member (800).

[0031] As explained above, in the capacitor device (1) of the present embodiment, since the thickness of each external voltage detection terminal (700) is greater than the thickness of the internal voltage detection terminal (300), the external voltage detection terminal (700) is suppressed from bending due to its own weight compared to the internal voltage detection terminal (300), so it is unnecessary to maintain the external voltage detection terminal (700) by the housing, and also, since the dimension (T1) of the housing (400) in the stacking direction is less than or equal to the length (T3) between a pair of external voltage detection terminals (700) in the stacking direction, the enlargement of the capacitor device (1) is avoided.

[0032] In addition, when the capacitor device is configured by stacking multiple capacitor modules, each comprising a plurality of stacked cells and a housing (400), a predetermined gap is formed between the capacitor modules arranged in the stacking direction so that adjacent capacitor modules do not come into contact with each other. Because of this, if the dimension (T1) of the housing (400) in the stacking direction is greater than the length (T3) between a pair of external voltage detection terminals (700) in the stacking direction, the thickness of the external current collector plate (500) formed between adjacent capacitor modules increases. However, in the capacitor device (1) of the present embodiment, since the dimension (T1) of the housing (400) in the stacking direction is less than or equal to the length (T3) between a pair of external voltage detection terminals (700) in the stacking direction, the increase in the thickness of the external current collector plate (500) is avoided, and thus the overall enlargement of the capacitor device is avoided.

[0033] In the above embodiment, as shown in FIGS. 4 and 5, the insulating member (800) may be formed between the external current collector plate (500) and the base portion (710) of the external voltage detection terminal (700).

[0034] As shown in FIGS. 6 and 7, the insulating member (800) may be formed between the end of the external voltage detection terminal (700) on the side (right side in FIG. 6) of the external current collector plate (500) to which the external voltage detection terminal (700) is connected and the external voltage detection terminal (700).

[0035] As shown in FIGS. 8 and 9, when the thickness of the conductive adhesive (600) is formed to be greater than the thickness of the external voltage detection terminal (700), the base portion (710) of the external voltage detection terminal (700) may be embedded in the conductive adhesive (600) with an insulating member (800) interposed therebetween. That is, the insulating member (800) may have a covering portion (810) covering the cross-section of the base portion (710) and an interposed portion (820) interposed between the external current collector plate (500) and the base portion (710).

[0036] As shown in FIGS. 10 and 11, the external voltage detection terminal (700) may be separated from the external current collector plate (500). That is, the space between the external current collector plate (500) and the external voltage detection terminal (700) may be insulated. In this case, the insulating member (800) is omitted. Also, in this case, the length between the outer surfaces of a pair of external voltage detection terminals (700) is set to be less than or equal to the length between the outer surfaces of a pair of external current collector plates (500).

[0037] It is understood by those skilled in the art that the exemplary embodiments described above are specific examples of the following embodiments.

[0038] [Mode 1]

[0039] An electrode stack comprising a plurality of bipolar electrodes stacked together, and a pair of outermost current collectors disposed on the outer side of the plurality of bipolar electrodes in the stacking direction of the plurality of bipolar electrodes, and

[0040] An internal voltage detection terminal connected to at least one of the plurality of bipolar electrodes, and

[0041] A housing that holds at least one of the internal voltage detection terminals, and

[0042] A pair of external voltage detection terminals electrically connected to each of the above pair of outermost current collectors, and

[0043] Each of the above plurality of bipolar electrodes is,

[0044] The whole house and,

[0045] A positive electrode active material layer formed on one side of the above-mentioned current collector, and

[0046] having a negative electrode active material layer formed on the other side of the above-mentioned current collector,

[0047] The above at least one internal voltage detection terminal is electrically connected to the bipolar electrode, and

[0048] Each of the above pair of external voltage detection terminals has a thickness greater than the thickness of the at least one internal voltage detection terminal,

[0049] The above housing is located between the pair of external voltage detection terminals in the stacking direction, and

[0050] A capacitor device in which the dimensions of the housing in the above stacking direction are less than or equal to the length between the pair of external voltage detection terminals in the above stacking direction.

[0051] In this capacitor, since the thickness of each external voltage detection terminal is greater than the thickness of the internal voltage detection terminal, it is unnecessary to maintain the external voltage detection terminal by a housing. Furthermore, since the dimensions of the housing in the stacking direction are less than or equal to the length between a pair of external voltage detection terminals in the stacking direction, the enlargement of the capacitor is avoided.

[0052] [Mode 2]

[0053] The apparatus further comprises a sealing member that seals the internal space formed between a pair of current collectors adjacent to each other in the stacking direction, and

[0054] The above-mentioned bag member is located between the above-mentioned pair of external voltage detection terminals, and

[0055] A capacitor device described in Embodiment 1, wherein the dimensions of the housing in the above stacking direction are less than or equal to the length of the sealing member in the above stacking direction.

[0056] In this embodiment, both the retention of the internal voltage detection terminal by the housing and the avoidance of increasing the size of the capacitor are more reliably achieved.

[0057] [Mode 3]

[0058] An external current collector plate disposed on the outer side of the electrode stack in the above stacking direction, and

[0059] A first adhesive portion having conductivity and connecting the outermost current collector and the external current collector plate, and

[0060] A second adhesive portion having conductivity and connecting the outermost current collector and the external voltage detection terminal is additionally provided,

[0061] The above external voltage detection terminal is electrically insulated from the above external current collector plate, in a capacitor device described in embodiment 1 or 2.

[0062] In this embodiment, since the external voltage detection terminal is electrically insulated from the external current collector plate, the accuracy of the voltage measured in the detection circuit connected to the external voltage detection terminal is suppressed due to the voltage drop caused by the resistance of the first adhesive part, compared to the case where a relatively large current flowing from the electrode laminate toward the external current collector plate through the first adhesive part flows from the external current collector plate toward the external voltage detection terminal.

[0063] [Mode 4]

[0064] A capacitor device described in Embodiment 3, further comprising an insulating member formed between the external voltage detection terminal and the external current collector plate.

[0065] [Mode 5]

[0066] The above external voltage detection terminal is separated from the above external current collector plate, in the capacitor device described in Embodiment 3.

[0067] [Mode 6]

[0068] A capacitor device described in any one of embodiments 3 to 5, wherein the length between the pair of external voltage detection terminals in the stacking direction is less than or equal to the length between the pair of outermost current collectors in the stacking direction.

[0069] In this embodiment, compared to the case where all detection terminals are retained in the housing, the capacitor is miniaturized in the stacking direction.

[0070] Although embodiments of the present invention have been described, the embodiments disclosed herein should be considered as illustrative and not limiting in all respects. The scope of the present invention is defined by the claims, and all modifications within the meaning and scope of the claims and equivalents are intended to be included.

Claims

Claim 1 An electrode stack comprising a plurality of bipolar electrodes stacked together and a pair of outermost current collectors disposed on the outer side of the plurality of bipolar electrodes in the stacking direction of the plurality of bipolar electrodes, an internal voltage detection terminal connected to at least one of the plurality of bipolar electrodes, a housing holding at least one of the internal voltage detection terminals, and a pair of external voltage detection terminals electrically connected to each of the pair of outermost current collectors, wherein each of the plurality of bipolar electrodes has a current collector, a positive electrode active material layer formed on one side of the current collector, and a negative electrode active material layer formed on the other side of the current collector, wherein the internal voltage detection terminal is electrically connected to the bipolar electrode, and each of the pair of external voltage detection terminals has a thickness greater than the thickness of the at least one internal voltage detection terminal, and the housing is located between the pair of external voltage detection terminals in the stacking direction, and the dimension of the housing in the stacking direction is the length between the pair of external voltage detection terminals in the stacking direction. A capacitor device comprising: an external current collector plate disposed on the outer side of the electrode laminate in the above stacking direction; a first adhesive part having conductivity and connecting the outermost current collector and the external current collector plate; and a second adhesive part having conductivity and connecting the outermost current collector and the external voltage detection terminal, wherein the external voltage detection terminal is electrically insulated from the external current collector plate. Claim 2 A capacitor device according to claim 1, further comprising a sealing member that seals an internal space formed between a pair of current collectors adjacent to each other in the stacking direction, wherein the sealing member is located between the pair of external voltage detection terminals, and the dimensions of the housing in the stacking direction are less than or equal to the length of the sealing member in the stacking direction. Claim 3 delete Claim 4 A capacitor device according to claim 1, further comprising an insulating member formed between the external voltage detection terminal and the external current collector plate. Claim 5 In claim 1, the external voltage detection terminal is separated from the external current collector plate, forming a capacitor device. Claim 6 A capacitor according to claim 1, wherein the length between the pair of external voltage detection terminals in the stacking direction is less than or equal to the length between the pair of outermost current collectors in the stacking direction.

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