Battery

Abstract

To provide a battery in which a short circuit that tends to raise the temperature of a positive electrode active material layer and a negative electrode active material layer hardly occurs between two current collector foils when an external force is imparted.SOLUTION: A battery includes a laminate 15 configured by laminating a plurality of bipolar electrodes 23 and a plurality of separators 25 in a lamination direction. The battery further includes: a frame body 30 that is made of resin and that is provided at an outer peripheral portion of the laminate such that the frame body is connected to current collector foils 18-1 that are parts of current collectors 18 of the bipolar electrodes where positive electrode active material layers 21 and negative electrode active material layers 19 are not formed; and spacers 27 that are made of an insulating material and that are located between the current collector foils and the separators such that the distance in a perpendicular direction that is a direction perpendicular to the lamination direction up to the positive electrode active material layers and the negative electrode active material layers is longer than the distance in the perpendicular direction up to the frame body.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a battery.

Background Art

[0002] Patent Document 1 below discloses a battery in which a plurality of electrodes including bipolar electrodes and a plurality of separators positioned between adjacent electrodes are laminated in a predetermined lamination direction. The bipolar electrode has a current collector, a positive electrode active material layer formed on one surface of the current collector and having an outer peripheral side end portion positioned on the inner peripheral side of the outer peripheral side end portion of the current collector, and a negative electrode active material layer formed on the other surface of the current collector and having an outer peripheral side end portion positioned on the inner peripheral side of the outer peripheral side end portion of the current collector. Further, this battery includes a resin-made frame provided at the outer peripheral portion of the laminate so as to be connected to the current collector foil which is a portion where the positive electrode active material layer and the negative electrode active material layer of each current collector are not formed. Further, this battery has a spacer positioned between adjacent current collector foils and connected to the inner peripheral surface of the frame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The spacer of the battery of Patent Document 1 above is connected to the inner peripheral surface of the frame. That is, the distance from the positive electrode active material layer and the negative electrode active material layer to the spacer is long. Therefore, when an external force is applied to the battery, a portion where the distance from the current collector foil of at least one current collector to the positive electrode active material layer and the negative electrode active material layer is short may be deformed, and there is a risk of contacting the current collector foil of another current collector while penetrating the separator. When two current collector foils are short-circuited in such a manner, the positive electrode active material layer and the negative electrode active material layer are likely to be heated to a high temperature due to the heat generated by the short circuit.

[0005] In view of the above facts, an object of the present invention is to provide a battery in which a short circuit that easily raises the temperature of the positive electrode active material layer and the negative electrode active material layer hardly occurs between two current collector foils when an external force is applied.

Means for Solving the Problems

[0006] The battery according to the first aspect includes a current collector, a positive electrode active material layer formed on one surface of the current collector and having an outer peripheral side end portion located on the inner peripheral side of the outer peripheral side end portion of the current collector, and the other surface of the current collector. A plurality of bipolar electrodes having a negative electrode active material layer formed thereon and having an outer peripheral side end portion located on the inner peripheral side of the outer peripheral side end portion of the current collector, and a plurality of separators located between the positive electrode active material layer and the negative electrode active material layer. It has a laminate formed by laminating the bipolar electrodes and the separators in a predetermined lamination direction, and is connected to a current collector foil which is a portion of each current collector where the positive electrode active material layer and the negative electrode active material layer are not formed. A resin-made frame provided on the outer periphery of the laminate, and a distance in the orthogonal direction, which is a direction orthogonal to the lamination direction up to the positive electrode active material layer and the negative electrode active material layer, is longer than the distance in the orthogonal direction up to the frame. And a spacer made of an insulating material located between the current collector foil and the separator.

[0007] When an external force is applied to the battery according to the first aspect, the current collector foil of at least one current collector may be deformed and contact another current collector foil while penetrating the separator. At this time, a spacer made of an insulating material located between the current collector foil and the separator suppresses the portion where the distance in the orthogonal direction to the positive electrode active material layer and the negative electrode active material layer of the current collector foil is short from contacting another current collector foil. Therefore, when an external force is applied to the battery according to the first aspect, a short circuit that easily raises the temperature of the positive electrode active material layer and the negative electrode active material layer hardly occurs between the two current collector foils.

[0008] In the battery of the second aspect, in the first aspect, the outer peripheral side end portion of the negative electrode active material layer is located on the outer peripheral side of the outer peripheral side end portion of the positive electrode active material layer, the spacer is provided on the current collector so as to face the positive electrode active material layer in the orthogonal direction from the outer peripheral side, and at least a part of the spacer is aligned with the outer peripheral side end portion of the negative electrode active material layer in the stacking direction.

[0009] In the battery of the second aspect, the distance in the orthogonal direction between the spacer and the positive electrode active material layer is short. Therefore, when an external force is applied to the battery of the second aspect, a short circuit that easily heats the positive electrode active material layer is less likely to occur between the two current collector foils.

[0010] In the battery of the third aspect, in the first aspect or the second aspect, the dimensions of the spacer and the positive electrode active material layer in the stacking direction are the same.

[0011] According to the third aspect, compared with the case where the dimension of the spacer in the stacking direction is smaller than the dimension of the positive electrode active material layer in the stacking direction, when an external force is applied to the battery, a short circuit that easily heats the positive electrode active material layer and the negative electrode active material layer is less likely to occur between the two current collector foils.

[0012] In the battery of the fourth aspect, in the first aspect or the second aspect, a sealing material separate from the spacer that seals the space between the current collector and the frame body in a liquid-tight state is provided between a part of the current collector and the frame body.

[0013] According to the fourth aspect, the space between a part of the current collector and the frame body is sealed in a liquid-tight state by a sealing material separate from the spacer.

[0014] In the battery of the fifth aspect, in the first aspect or the second aspect, when the battery is viewed along the stacking direction, the distance in the orthogonal direction between the outer peripheral surface of the portion of the spacer located between the positive electrode active material layer or the negative electrode active material layer and the frame body and the outer peripheral surface of the negative electrode active material layer is 10 times or more the distance in the stacking direction between adjacent current collectors.

[0015] According to the fifth aspect, when an external force is applied to the battery, a short circuit that easily causes the positive electrode active material layer and the negative electrode active material layer to heat up is less likely to occur between the two current collectors, as compared to the case where the distance in the orthogonal direction between the outer peripheral surface of the portion located between the positive electrode active material layer or the negative electrode active material layer of the spacer and the frame body and the outer peripheral surface of the negative electrode active material layer is less than 10 times the distance in the stacking direction between adjacent current collectors.

Advantages of the Invention

[0016] As described above, the battery according to the present invention has an excellent effect that when an external force is applied to the battery, a short circuit that easily causes the positive electrode active material layer and the negative electrode active material layer to heat up is less likely to occur between the two current collectors.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0018] Hereinafter, a bipolar lithium-ion secondary battery according to an embodiment (hereinafter referred to as battery 10) will be described. The battery 10 can be mounted on various devices. The battery 10 of the present embodiment is mounted on a battery electric vehicle (BEV) and can supply power to an electric motor that is a drive source. The arrows UP, FR, and LH shown in each drawing indicate the upper side in the vertical direction, the front side in the front-rear direction, and the left side in the left-right direction, respectively.

[0019] First, the basic configuration of the battery 10 will be described. The battery 10 of the present embodiment includes a laminate 15 and a resin member (frame) 30.

[0020] The laminate 15 is formed by laminating a plurality of electrodes, a plurality of separators 25, and a plurality of spacers 27 in a predetermined lamination direction (the vertical direction in FIG. 1). These electrodes include a negative terminal electrode 17, a positive terminal electrode 20, and a plurality of bipolar electrodes 23. Note that in FIG. 2, illustration of some of the bipolar electrodes 23 is omitted.

[0021] The negative terminal electrode 17 includes a current collector 18 and a negative electrode active material layer 19 provided on one surface (the upper surface in FIG. 1) of the current collector 18. The positive terminal electrode 20 includes a current collector 18 and a positive electrode active material layer 21 provided on one surface (the lower surface in FIG. 1) of the current collector 18. Each bipolar electrode 23 includes a current collector 18, a negative electrode active material layer 19 provided on one surface (the upper surface in FIG. 2) of the current collector 18, and a positive electrode active material layer 21 provided on the other surface (the lower surface in FIG. 2) of the current collector 18.

[0022] A separator 25 is provided between the negative electrode active material layer 19 of the negative terminal electrode 17 and the positive electrode active material layer 21 of the bipolar electrode 23 adjacent to the negative terminal electrode 17. Further, a separator 25 is provided between the positive electrode active material layer 21 of the positive terminal electrode 20 and the negative electrode active material layer 19 of the bipolar electrode 23 adjacent to the positive terminal electrode 20. Further, a separator 25 is provided between the negative electrode active material layer 19 of the adjacent bipolar electrodes 23 and the positive terminal electrode 20.

[0023] As shown in FIGS. 1 and 2, both end faces in the lamination direction of the laminate 15 including the negative terminal electrode 17, the positive terminal electrode 20, the bipolar electrode 23, and the separator 25 are constituted by the current collector 18. As shown in FIGS. 2 and 3, the outer peripheral portion of each current collector 18 when the laminate 15 is viewed along the lamination direction is a current collector foil 18-1 located on the outer peripheral side of the outer peripheral side end portions of the negative electrode active material layer 19 and the positive electrode active material layer 21.

[0024] The shape (planar shape) of the laminate 15 of the present embodiment when viewed along the lamination direction is rectangular. That is, the shapes of the current collector 18, the negative electrode active material layer 19, the positive electrode active material layer 21, and the separator 25 when the laminate 15 is viewed along the lamination direction are rectangular. Further, as is clear from FIG. 2, when the laminate 15 is viewed along the lamination direction, the outer peripheral side end portions of each negative electrode active material layer 19 are located on the outer peripheral side of the outer peripheral side end portions of each positive electrode active material layer 21. Further, the shapes of each negative electrode active material layer 19 when the laminate 15 is viewed along the lamination direction are the same as each other, and the shapes of each positive electrode active material layer 21 when the laminate 15 is viewed along the lamination direction are the same as each other. Further, the shapes of each current collector 18 when the laminate 15 is viewed along the lamination direction are the same as each other. Further, the shapes of each separator 25 when the laminate 15 is viewed along the lamination direction are the same as each other.

[0025] Further, as shown in FIGS. 2 and 3, on the lower surface of the current collecting foil 18-1 of the current collector 18 of the positive terminal electrode 20 and each bipolar electrode 23, a spacer 27 which is a frame body having a rectangular shape when viewed along the lamination direction is fixed. The spacer 27 is made of a material having insulating properties and heat resistance. For example, the constituent material of the spacer 27 is a silicone resin. As is clear from FIG. 2, the rear portions 27B of each spacer 27 are aligned in the vertical direction with the rear end portions of each negative electrode active material layer 19, and the front portions 27F of each spacer 27 are aligned in the vertical direction with the front end portions of each negative electrode active material layer 19. Note that the left side portions 27L (see FIG. 3) of each spacer 27 are aligned in the vertical direction with the left end portions of each negative electrode active material layer 19, and the right side portions 27R (see FIG. 3) of each spacer 27 are aligned in the vertical direction with the right end portions of each negative electrode active material layer 19. Further, the inner peripheral surface of each spacer 27 and the outer peripheral surface of each positive electrode active material layer 21 face each other while forming a minute gap. Further, the vertical dimension (thickness) of each spacer 27 is the same as the vertical dimension (thickness) of each positive electrode active material layer 21. Therefore, the lower surface of each spacer 27 contacts the upper surface of the separator 25.

[0026] Here, a direction orthogonal to the stacking direction (vertical direction) is defined as the orthogonal direction. That is, the left - right direction and the front - back direction are included in the orthogonal direction. The front - back direction distance 27LT (see FIG. 2) between the front end face of the front portion 27F of the spacer 27 and the front end face of the negative electrode active material layer 19, the front - back direction distance 27LT (see FIG. 2) between the rear end face of the rear portion 27B of the spacer 27 and the rear end face of the negative electrode active material layer 19, the left - right direction distance 27LT (not shown) between the left side face of the left side portion of the spacer 27 and the left end face of the negative electrode active material layer 19, and the left - right direction distance 27LT (not shown) between the right side face of the right side portion of the spacer 27 and the right end face of the negative electrode active material layer 19 are significantly longer than the stacking direction distance 18DL (see FIG. 2) between adjacent current collectors 18. This distance 18DL is the vertical direction distance between the upper surface of one current collector 18 and the lower surface of the current collector 18 adjacent to this current collector 18 from above. Further, it is preferable that each distance 27LT is 10 times or more the length of the distance 18DL.

[0027] On the outer peripheral portion of the laminate 15, a resin member 30, which is an integrally - molded resin product, is provided. The resin member 30 is integrated with the outer peripheral portion of the laminate 15 in an air - tight and liquid - tight state so as to cover the outer peripheral portion of the laminate 15. The shape when cut along a cross - section orthogonal to the stacking direction of the resin member 30 is a rectangle with a rectangular opening formed in the central portion. The resin member 30 is composed of an insulating resin material. The constituent material of the resin member 30 is, for example, polypropylene, polyethylene, polystyrene, ABS resin, acid - modified polypropylene, acid - modified polyethylene, or acrylonitrile styrene resin. For example, the resin member 30 may be integrally provided on the outer peripheral portion of the laminate 15 by insert molding performed while disposing the laminate 15 inside a molding die (not shown).

[0028] Although not shown in the figure, an electrolytic solution is provided inside the laminate 15, and the electrolytic solution is impregnated in the negative terminal electrode 17, the positive terminal electrode 20, and the bipolar electrode 23.

[0029] As further shown in FIG. 2, a sealing material 29 made of an insulating material is formed in a liquid-tight state on the entire surface of the end portion on the inner peripheral surface side of the central opening 30S of the current collector foil 18-1 of each current collector 18 and on the inner peripheral surface of the central opening 30S. In FIG. 2, the sealing material 29 is shown only for the current collector foil 18-1 of the lowermost current collector 18, and the illustration of the sealing material 29 for the other current collectors 18 (current collector foils 18-1) is omitted.

[0030] The battery 10 configured as described above is fixed via fixing means to the upper surface of a substantially horizontal plate material (not shown) that forms part of the vehicle body constituent member of the electric vehicle.

[0031] As shown in FIGS. 1 and 2, the outer peripheral side end portions of the current collectors 18 of the negative terminal electrode 17, the positive terminal electrode 20, and the bipolar electrode 23 and the outer peripheral side end portions of the separators 25 are located inside the resin member 30. On the other hand, the outer peripheral side end portions of the negative electrode active material layers 19 and the positive electrode active material layers 21 are located on the inner peripheral side of the inner peripheral surface of the central opening 30S of the resin member 30. Further, the current collector 18 of the negative terminal electrode 17 is exposed through one opening end portion of the central opening 30S, and the current collector 18 of the positive terminal electrode 20 is exposed through the other opening end portion of the central opening 30S. Therefore, the electric power generated by the battery 10 can be supplied to various electrical devices and electronic devices (not shown) provided in the electric vehicle through a conductive member (not shown) connected to the current collector 18 of the negative terminal electrode 17 through one opening end portion of the central opening 30S and a conductive member (not shown) connected to the current collector 18 of the positive terminal electrode 20 through the other opening end portion of the central opening 30S.

[0032] (Operation and Effect) Next, the operation and effect of the present embodiment will be described.

[0033] Here, assume a case where a vehicle (not shown) traveling forward in the rear area of the electric vehicle collides with the rear end of the electric vehicle. When such a collision occurs in the electric vehicle, due to the impact generated in the electric vehicle, a member (not shown) provided on the vehicle body and located immediately behind the battery 10 may move relatively forward with respect to the battery 10, and this member may collide violently with the rear portion 30R (see FIGS. 1 and 2) of the resin member 30.

[0034] In this case, due to an external force applied to the battery 10, for example, the current collector foil 18-1 of the current collector 18U, which is one of the current collectors 18, may be deformed and come into contact with the current collector foil 18-1 of the current collector 18D, which is another current collector, while penetrating the adjacent separator 25. However, as shown in FIG. 2, the longitudinal distance from the rear portion 27B of the spacer 27 fixed to the lower surface of the current collector foil 18-1 of the current collector 18U to the rear portion 30R of the resin member 30 is shorter than the longitudinal distance from the rear portion 27B to the rear end surfaces of the negative electrode active material layer 19 and the positive electrode active material layer 21. That is, the rear portion 27B is fixed to the current collector foil 18-1 of the current collector 18U in a state where it is close to the rear ends of the negative electrode active material layer 19 and the positive electrode active material layer 21. Therefore, a portion located behind the rear portion 27B of the current collector foil 18-1 of the current collector 18U comes into contact with the current collector foil 18-1 of the current collector 18D while penetrating the adjacent separator 25. That is, the spacer 27 (rear portion 27B) located between the current collector 18U and the separator 25 suppresses the portion of the current collector foil 18-1 of the current collector 18U with a short distance to the negative electrode active material layer 19 and the positive electrode active material layer 21 from coming into contact with the current collector foil 18-1 of the current collector 18D. For example, there is almost no possibility that a portion located in front of the rear end of the rear portion 27B of the current collector foil 18-1 of the current collector 18U comes into contact with the current collector foil 18-1 of the current collector 18D. If a portion of the current collector foil 18-1 of the current collector 18U of the battery 10 with a short distance to the negative electrode active material layer 19 and the positive electrode active material layer 21 comes into contact with the current collector foil 18-1 of the current collector 18D, since the distance between the short-circuit portion of the current collectors 18U and 18D and the negative electrode active material layer 19 and the positive electrode active material layer 21 is short, there is a possibility that the negative electrode active material layer 19 and the positive electrode active material layer 21 may be heated to a high temperature by the heat generated at the short-circuit portion. On the other hand, when a portion located behind the rear portion 27B of the current collector foil 18-1 of the current collector 18U comes into contact with the current collector foil 18-1 of the current collector 18D while penetrating the adjacent separator 25, since the distance between the short-circuit portion of the current collectors 18U and 18D and the negative electrode active material layer 19 and the positive electrode active material layer 21 becomes long, the possibility that the negative electrode active material layer 19 and the positive electrode active material layer 21 are heated to a high temperature by the heat generated at the short-circuit portion is small.

[0035] Furthermore, when the distance 27LT in the front-rear direction between the rear end surface of the rear part 27B and the rear end surface of the negative electrode active material layer 19 is made to be 10 times or more the length of the distance 18DL in the stacking direction between adjacent current collectors 18, the possibility that the negative electrode active material layer 19 and the positive electrode active material layer 21 are heated to a high temperature by the heat generated at the short-circuit site is smaller than when the distance 27LT is smaller than 10 times the distance 18DL.

[0036] Furthermore, the vertical dimension (thickness) of each spacer 27 is the same as the vertical dimension (thickness) of each positive electrode active material layer 21. That is, before an external force acts on the battery 10, the upper surface of the spacer 27 contacts the lower surface of the current collector foil 18-1 and the lower surface of the spacer 27 contacts the upper surface of the separator 25. Therefore, before an external force acts on the battery 10, the spacer 27 is more likely to prevent the two current collector foils 18-1 from short-circuiting compared to the case where the spacer 27 does not contact the lower surface of the current collector foil 18-1 or the upper surface of the separator 25.

[0037] As described above, the battery 10 according to the embodiment has been described, but these can be appropriately modified in design without departing from the gist of the present invention.

[0038] The battery 50 of the first modified example shown in Fig. 4 has the same structure as the battery 10 of the embodiment, except that the dimensions of the spacer 51 in the front-rear direction and the left-right direction are different from those of the spacer 27. The rear part 51SR of the inner peripheral surface of the spacer 51 is aligned with the rear end surface of the negative electrode active material layer 19 in the vertical direction. That is, the front-rear positions of the rear part 51SR of the inner peripheral surface of the spacer 51 and the rear end surface of the negative electrode active material layer 19 are the same. Although not shown, the front part of the inner peripheral surface of the spacer 51 is aligned with the front end surface of the negative electrode active material layer 19 in the vertical direction, the left side part of the inner peripheral surface of the spacer 51 is aligned with the left end surface of the negative electrode active material layer 19 in the vertical direction, and the right side part of the inner peripheral surface of the spacer 51 is aligned with the right end surface of the negative electrode active material layer 19 in the vertical direction. Further, the front-rear distance 51LT between the front end surface of the front part of the spacer 51 and the front end surface of the negative electrode active material layer 19, the front-rear distance 51LT between the rear end surface of the rear part 51R of the spacer 51 and the rear end surface of the negative electrode active material layer 19, the left-right distance 51LT between the left side surface of the left side part of the spacer 51 and the left end surface of the negative electrode active material layer 19, and the left-right distance 51LT between the right side surface of the right side part of the spacer 51 and the right end surface of the negative electrode active material layer 19 are significantly longer than the distance 18DL. Further, it is preferable that each distance 51LT is 10 times or more the length of the distance 18DL. In the battery 50 of the first modified example shown in Fig. 4, when an external force is applied to the battery 50, the spacer 51 (rear part 51R) suppresses the collector foil 18-1 of the current collector 18U from contacting the collector foil 18-1 of the current collector 18D at a site where the front-rear distance to the negative electrode active material layer 19 and the positive electrode active material layer 21 of the collector foil 18-1 of the current collector 18U is short. Therefore, when an external force is applied to the battery 50, a short circuit that easily raises the temperature of the negative electrode active material layer 19 and the positive electrode active material layer 21 is less likely to occur between the two collector foils 18-1.

[0039] The battery 60 of the second modified example shown in FIG. 5 has the same structure as the battery 10 of the embodiment, except that the dimensions of the spacer 61 in the front-rear direction and the left-right direction are different from those of the spacer 27. The rear part 61SR of the inner peripheral surface of the spacer 61 contacts the rear end surface of the positive electrode active material layer 21. Although not shown, the front part of the inner peripheral surface of the spacer 61 contacts the front end surface of the positive electrode active material layer 21, the left side part of the inner peripheral surface of the spacer 61 contacts the left end surface of the positive electrode active material layer 21, and the right side part of the inner peripheral surface of the spacer 61 contacts the right end surface of the positive electrode active material layer 21. Further, the front-rear direction distance 61LT between the front end surface of the front part of the spacer 61 and the front end surface of the negative electrode active material layer 19, the front-rear direction distance 61LT between the rear end surface of the rear part 61R of the spacer 61 and the rear end surface of the negative electrode active material layer 19, the left-right direction distance 61LT between the left side surface of the left side part of the spacer 61 and the left end surface of the negative electrode active material layer 19, and the left-right direction distance 61LT between the right side surface of the right side part of the spacer 61 and the right end surface of the negative electrode active material layer 19 are significantly longer than the distance 18DL. Further, each distance 61LT is preferably 10 times or more the length of the distance 18DL. In the battery 60 of the second modified example shown in FIG. 5, the spacer 61 (rear part 61R) suppresses the contact of the portion where the front-rear direction distance of the current collector foil 18-1 of the current collector 18U to the negative electrode active material layer 19 and the positive electrode active material layer 21 is short with the current collector foil 18-1 of the current collector 18D. Therefore, when an external force is applied to the battery 60, a short circuit that easily causes the negative electrode active material layer 19 and the positive electrode active material layer 21 to heat up is less likely to occur between the two current collector foils 18-1. Further, since the inner peripheral side end of the spacer 61 is located on the inner peripheral side (positive electrode active material layer 21 side) than the inner peripheral side ends of the spacers 27 and 51, the mechanical strength of the battery 60 is higher than that of the batteries 10 and 50.

[0040] The battery 70 of the third modification example shown in FIG. 6 has the same structure as the battery 10 of the embodiment, except that the dimensions of the spacer 71 in the front-rear direction and the left-right direction are different from those of the spacer 27 and the spacer 72 is provided. The rear part 71SR of the inner peripheral surface of the spacer 71 facing the positive electrode active material layer 21 in the direction orthogonal to the positive electrode active material layer 21 contacts the rear end surface of the positive electrode active material layer 21. Although not shown, the front part of the inner peripheral surface of the spacer 71 contacts the front end surface of the positive electrode active material layer 21, the left side part of the inner peripheral surface of the spacer 71 contacts the left end surface of the positive electrode active material layer 21, and the right side part of the inner peripheral surface of the spacer 71 contacts the right end surface of the positive electrode active material layer 21. Further, the rear part 71TR of the outer peripheral surface of the spacer 71 contacts the rear part of the inner peripheral surface of the central opening 30S of the resin member 30. Although not shown, the front part of the outer peripheral surface of the spacer 71 contacts the front part of the inner peripheral surface of the central opening 30S, the left side part of the outer peripheral surface of the spacer 71 contacts the left side part of the inner peripheral surface of the central opening 30S, and the right side part of the outer peripheral surface of the spacer 71 contacts the right side part of the inner peripheral surface of the central opening 30S.

[0041] The battery 70 includes a spacer 72 facing the negative electrode active material layer 19 in the direction orthogonal to the negative electrode active material layer 19. The shape of the spacer 72 when viewed along the stacking direction is also a rectangular frame body, similar to the spacers 27, 51, 61, and 71. The vertical dimension (thickness) of the spacer 72 is the same as the vertical dimension (thickness) of each negative electrode active material layer 19. The rear part 72SR of the inner peripheral surface of the spacer 72 contacts the rear end surface of the negative electrode active material layer 19. Although not shown, the front part of the inner peripheral surface of the spacer 72 contacts the front end surface of the negative electrode active material layer 19, the left side part of the inner peripheral surface of the spacer 72 contacts the left end surface of the negative electrode active material layer 19, and the right side part of the inner peripheral surface of the spacer 72 contacts the right end surface of the negative electrode active material layer 19. Further, the rear part 72TR of the outer peripheral surface of the spacer 72 contacts the rear part of the inner peripheral surface of the central opening 30S of the resin member 30. The front part of the outer peripheral surface of the spacer 72 contacts the front end surface of the inner peripheral surface of the central opening 30S, the left side part of the outer peripheral surface of the spacer 72 contacts the left end surface of the inner peripheral surface of the central opening 30S, and the right side part of the outer peripheral surface of the spacer 72 contacts the right end surface of the inner peripheral surface of the central opening 30S.

[0042] Furthermore, the front-back distance 712LT between the front end faces of the front parts of the spacers 71 and 72 and the front end face of the negative electrode active material layer 19, the front-back distance 712LT between the rear end faces of the rear parts 71R and 72R and the rear end face of the negative electrode active material layer 19, the left-right distance 712LT between the left side faces of the left side parts of the spacers 71 and 72 and the left end face of the negative electrode active material layer 19, and the left-right distance 712LT between the right side faces of the right side parts of the spacers 71 and 72 and the right end face of the negative electrode active material layer 19 are significantly longer than the distance 18DL. Furthermore, it is preferable that each distance 712LT is 10 times or more the length of the distance 18DL.

[0043] In this way, the annular space between the outer peripheral surface of the positive electrode active material layer 21 and the inner peripheral surface of the central opening 30S of the resin member 30 is completely blocked by the spacer 71, and the annular space between the outer peripheral surface of the negative electrode active material layer 19 and the inner peripheral surface of the central opening 30S of the resin member 30 is completely blocked by the spacer 72. Therefore, when an external force acts on the battery 70, there is almost no possibility of a short circuit occurring between the two current collector foils 18-1. When the rear part 30R is damaged due to a collision, there is a possibility that the parts located behind the rear parts 71TR and 72TR of the current collectors 18U and 18D may short-circuit. However, in this case, since the front-back distance between the short-circuit part of the current collectors 18U and 18D and the negative electrode active material layer 19 and the positive electrode active material layer 21 becomes long, there is little possibility that the negative electrode active material layer 19 and the positive electrode active material layer 21 will be heated to a high temperature by the heat generated at the short-circuit part.

[0044] The vertical dimensions (thicknesses) of the spacers 27, 51, 61, and 71 may be smaller than the vertical dimensions (thicknesses) of each positive electrode active material layer 21. Also, the vertical dimension (thickness) of the spacer 72 may be smaller than the vertical dimension (thickness) of each negative electrode active material layer 19.

[0045] The battery of the present invention may include only one of the spacer facing the positive electrode active material layer 21 in a direction orthogonal thereto and the spacer facing the negative electrode active material layer 19 in a direction orthogonal thereto.

[0046] The number of electrodes provided in the battery 10 may be any plural number.

[0047] The battery 10 may be provided in a device different from an electric vehicle.

Explanation of Signs

[0048] 10 Lithium-ion secondary battery (battery) 15 Laminate 18 18U 18D Current collector 18-1 Current collector foil 18DL Distance 19 Negative electrode active material layer 21 Positive electrode active material layer 23 Bipolar electrode 25 Separator 27 Spacer 29 Sealing material 30 Resin member (frame) 50 Lithium-ion secondary battery (battery) 51 Spacer 60 Lithium-ion secondary battery (battery) 61 Spacer 70 Lithium-ion secondary battery (battery) 71 Spacer 72 Spacer

Claims

1. A plurality of bipolar electrodes having a current collector, a positive electrode active material layer formed on one surface of the current collector and having an outer peripheral side end portion located on the inner peripheral side of the outer peripheral side end portion of the current collector, and a negative electrode active material layer formed on the other surface of the current collector and having an outer peripheral side end portion located on the inner peripheral side of the outer peripheral side end portion of the current collector, and a plurality of separators located between the positive electrode active material layer and the negative electrode active material layer, and having a laminate formed by laminating the bipolar electrodes and the separators in a predetermined lamination direction, A resin-made frame provided at the outer periphery of the laminate so as to be connected to a current collector foil which is a portion of each current collector where the positive electrode active material layer and the negative electrode active material layer are not formed, A spacer made of an insulating material located between the current collector foil and the separator such that a distance in a direction orthogonal to the lamination direction, which is the direction orthogonal to the lamination direction up to the positive electrode active material layer and the negative electrode active material layer, is longer than a distance in the orthogonal direction up to the frame, A battery comprising the above.

2. The outer peripheral side end portion of the negative electrode active material layer is located on the outer peripheral side of the outer peripheral side end portion of the positive electrode active material layer, The spacer is provided on the current collector so as to face the positive electrode active material layer in the orthogonal direction from the outer peripheral side, The battery according to claim 1, wherein at least a part of the spacer is aligned with the outer peripheral side end portion of the negative electrode active material layer in the lamination direction.

3. The battery according to claim 1 or claim 2, wherein the spacer and the positive electrode active material layer have the same dimension in the lamination direction.

4. The battery according to claim 1 or claim 2, wherein a sealing material separate from the spacer for sealing the space between the current collector and the frame in a liquid-tight state is provided between a part of the current collector and the frame.

5. The battery according to claim 1 or claim 2, wherein when the battery is viewed along the stacking direction, the distance in the orthogonal direction between the outer peripheral surface of the portion of the spacer located between the positive electrode active material layer or the negative electrode active material layer and the frame body and the outer peripheral surface of the negative electrode active material layer is 10 times or more the distance in the stacking direction between adjacent current collectors.

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