JP7363679B2 - Power storage device - Google Patents

Description

The present disclosure relates to a power storage device.

As a conventional power storage module, a power storage module is known that includes a bipolar electrode in which a positive electrode is formed on one side of a current collector and a negative electrode is formed on the other side (see, for example, Patent Document 1 below). The electricity storage module described in Patent Document 1 below includes an electrode stack having a plurality of stacked bipolar electrodes, and a sealing body that seals an internal space formed between adjacent electrodes.

In a power storage device including such a power storage module, a plurality of power storage modules are stacked with conductive plates interposed therebetween. Adjacent power storage modules are electrically connected to each other via conductive plates.

JP2011-204386A

In power storage devices, undulations (unevenness) may occur on the contact surface with the conductive plate of the power storage module due to thickness tolerances of the electrodes and separators included in the electrode laminate of the power storage module, or the formation conditions of the sealing body. be. When the conductive plate is composed of one plate-like member, if the contact surface with the conductive plate is undulated, the contact area between the conductive plate and the power storage module may be reduced. If the contact area decreases, there is a risk that the resistance between the conductive plate and the power storage module will increase.

On the other hand, instead of configuring the conductive plate with one plate-like member, a mode can be considered in which the conductive plate is configured by combining a plurality of plate-like members. In this aspect, the followability to the surface of the electricity storage module can be improved by making the connecting portions between the plate-like members variable in the stacking direction of the electrode stack. However, when using a conductive plate composed of a plurality of plate-like members, positioning of the conductive plate with respect to the electricity storage module, transportation of the conductive plate, etc. are more difficult than when using a conductive plate composed of a single plate-like member. It becomes complicated. For this reason, a problem arises in that the ease of assembly when stacking on the electricity storage module deteriorates.

An object of the present disclosure is to provide a power storage device having a conductive plate that can ensure followability to a contact surface of a power storage module and can suppress deterioration in assemblability during manufacturing.

A power storage device according to one aspect of the present disclosure is a power storage device including a power storage module and a conductive plate stacked on the power storage module in a first direction, wherein the power storage modules are stacked on each other in the first direction. It has an electrode stack having a plurality of current collector plates, and a sealing body provided so as to surround the side surface of the electrode stack, and the plurality of current collector plates are a first current collector plate included in the negative terminal electrode. and a second current collector plate included in the positive terminal electrode, and a third current collector plate included in each of the plurality of bipolar electrodes provided between the negative terminal electrode and the positive terminal electrode, and an electrode stack. The current collector plate disposed at the stacked end has an exposed surface exposed from the sealing body, the conductive plates are arranged in a second direction perpendicular to the first direction, and are connected to each other by a connecting part, and The connecting portion includes a first plate-like member and a second plate-like member that are in contact with the exposed surface, and the connecting portion has a convex connecting portion that projects from the first plate-like member toward the second plate-like member in the second direction; a concave connecting portion that is recessed toward the protruding direction of the convex connecting portion in the second direction and that accommodates the convex connecting portion; Contact.

In this power storage device, the conductive plates include a first plate member and a second plate member arranged in a second direction perpendicular to the first direction, connected to each other by a connecting portion, and in contact with the exposed surface. Thereby, by adjusting the number of plate-like members included in the conductive plate, the dimensions of the conductive plate in the second direction can be easily adjusted. Therefore, the shape of the conductive plate can be made to follow the shape of the contact surface (exposed surface) of the electricity storage module, compared to the case where the conductive plate is composed of a single plate-like member. Furthermore, the connecting portion includes a convex connecting portion and a concave connecting portion that accommodates the convex connecting portion, and the first plate-like member and the second plate-like member are in contact with each other in the connecting portion. Thereby, by sandwiching the conductive plate along the second direction, the first plate-like member and the second plate-like member can be integrally transported. Thereby, positioning, transportation, etc. of each plate member in the electricity storage module can be facilitated. Therefore, according to one aspect of the present disclosure, it is possible to provide a power storage device having a conductive plate that can ensure followability to the contact surface of a power storage module and can suppress deterioration in assemblability during manufacturing.

The first plate member has a first end face facing the second plate member in the second direction, the convex connecting portion protrudes from the first end face toward the second plate member, and the concave connecting portion has a first end face facing the second plate member in the second direction. , may contact the first end surface. In this case, it is possible to suppress the generation of a gap between the first end surface of the first plate member and the concave connecting portion of the connecting portion. Thereby, when internal pressure is generated in the electricity storage module, it is possible to suppress the fourth current collector plate from entering the gap.

The protrusion length of the convex connecting portion in the second direction may be shorter than the depth of the concave connecting portion in the second direction. In this case, it is possible to prevent the convex connecting portion from interfering with the contact between the concave connecting portion and the first plate member along the second direction.

The second plate-like member may have a second end surface that faces the first plate-like member in the second direction and forms the bottom of the concave connecting portion, and the convex connecting portion may contact the second end surface. . For example, when a seal member is provided on the exposed surface so as to overlap the gap between the concave connecting portion and the first plate member, a portion of the seal member enters the gap. This makes it difficult for the sealing member to spread between the conductive plate and the fourth current collector plate. Therefore, an increase in contact resistance between the conductive plate and the power storage module due to the seal member can be suppressed.

The protrusion length of the convex connecting portion in the second direction may be longer than the depth of the concave connecting portion in the second direction. In this case, it is possible to prevent the concave connecting portion from interfering with the contact between the convex connecting portion and the second plate member along the second direction.

At least a portion of the concave connecting portion may curve toward and contact the convex connecting portion in the first direction. In this case, the connecting portion can function as a reinforcing portion that reinforces the strength of the conductive plate along the first direction.

The concave connecting portion has a pair of walls that protrude in the second direction from each of both ends of the second plate member in the first direction, and each of the pair of walls includes a base and a wall that extends from the base in the second direction. The distance between the tips in the first direction may be greater as the distance between the tips in the first direction approaches the tip of the wall portion in the second direction. In this case, the convex connecting portion is easily accommodated in the concave connecting portion.

The first plate member may have a convex connecting portion, and the second plate member may have a concave connecting portion. In this case, the number of parts of the conductive plate can be reduced.

An active material layer may not be provided on the current collector plate disposed at the stacked end of the electrode stack. Alternatively, the current collector plate having an exposed surface may be a first current collector plate or a second current collector plate.

According to one aspect of the present disclosure, it is possible to provide a power storage device having a conductive plate that can ensure followability to a contact surface of a power storage module and can suppress deterioration in assemblage during manufacturing.

FIG. 1 is a schematic cross-sectional view showing an example of a power storage device. FIG. 2 is a sectional view showing the internal configuration of the power storage module. FIG. 3 is a plan view showing a power storage module and a conductive plate on the power storage module. FIG. 4 is a perspective view of the plate-like member of the conductive plate. FIG. 5 is a perspective view of the plate-like member of the conductive plate. FIG. 6 is a perspective view of the detection element. FIG. 7 is a plan view for explaining the position where the seal member is provided. FIGS. 8(a) and 8(b) are cross-sectional views for explaining a method of sealing between plate-like members using the second seal portion. FIG. 9 is a cross-sectional view for explaining a method of sealing the space between the power storage module and the conductive plate using the first seal portion. FIG. 10 is a schematic cross-sectional view showing a part of the power storage module according to the first modification. FIG. 11(a) is a schematic sectional view showing a part of the electricity storage module according to the second modification, and FIG. 11(b) is a schematic sectional view showing a state in which the plate-like members are sealed by the second seal portion. FIG.

Hereinafter, embodiments according to one aspect of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and redundant description will be omitted.

FIG. 1 is a schematic cross-sectional view showing an example of a power storage device according to this embodiment. A power storage device 1 shown in FIG. 1 is used, for example, as a battery for various vehicles such as a forklift, a hybrid vehicle, and an electric vehicle. The power storage device 1 includes a module stack 2 including a plurality of stacked power storage modules 4, and a restraining member 3 that applies a restraint load to the module stack 2 in the stacking direction of the module stack 2. In the following description, the stacking direction of the module laminate 2 will be referred to as the Z direction (first direction), and the directions perpendicular to the stacking direction will be referred to as the X direction and the Y direction (second direction), respectively.

The module stack 2 includes a power storage module 4, a conductive plate 5 stacked on the power storage module 4, a detection element 70 (see FIG. 3), and a seal member 80 (see FIG. 7). The detection element 70 and the seal member 80 will be described later. In this embodiment, the module stack 2 includes a plurality of power storage modules 4 and a plurality of conductive plates 5. The number of power storage modules 4 is, for example, five, and the number of conductive plates 5 is, for example, four. The power storage module 4 is a bipolar battery and has a rectangular shape when viewed from the Z direction. The power storage module 4 is, for example, a secondary battery such as a nickel metal hydride secondary battery or a lithium ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-metal hydride secondary battery will be exemplified as the power storage module 4.

The plurality of power storage modules 4 are stacked along the Z direction with conductive plates 5 interposed therebetween, and are electrically connected in series in the Z direction. The conductive plate 5 is a plate-shaped member made of a conductive material such as metal. Examples of the material for the conductive plate 5 include aluminum. A plating layer of, for example, nickel may be formed on the surface of the conductive plate 5. In the example shown in FIG. 1, the area of the conductive plate 5 viewed from the Z direction is smaller than the area of the power storage module 4, but the area is not limited to this. For example, from the viewpoint of improving heat dissipation, the area of the conductive plate 5 may be the same as the area of the power storage module 4, or may be larger than the area of the power storage module 4.

The plurality of conductive plates 5 include a plurality of (two in this embodiment) conductive plates 5A arranged between adjacent power storage modules 4 in the Z direction, and a plurality (in this embodiment) of conductive plates 5A located at the stacked ends of the module stack 2. 2) conductive plates 5B. Adjacent power storage modules 4 are electrically connected to each other via a conductive plate 5A. An insulating plate B is arranged outside the conductive plate 5B. A negative electrode terminal 7 is connected to one conductive plate 5B, and a positive electrode terminal 6 is connected to the other conductive plate 5B. Each of the positive electrode terminal 6 and the negative electrode terminal 7 is drawn out, for example, from the edge of the conductive plate 5B in the X direction.

A plurality of through holes (flow paths) 5a through which a cooling fluid F (see FIGS. 3 and 4) such as air flows are provided inside the conductive plate 5A arranged between the power storage modules 4. The plurality of through holes 5a constitute a cooling mechanism for cooling the power storage module 4. The conductive plate 5A has a function as a connecting member that electrically connects adjacent power storage modules 4 to each other. In addition, the conductive plate 5A has a function as a heat sink that radiates heat from the power storage module 4. Specifically, the conductive plate 5A functions as a heat sink by transmitting the heat transmitted from the power storage module 4 to the cooling fluid F passing through the plurality of through holes 5a.

The restraining member 3 includes a pair of end plates 8 that sandwich the module stack 2 in the Z direction, and a fastening bolt 9 and a nut 10 that fasten the end plates 8 together. End plate 8 is a plate-like member that has a rectangular shape when viewed from the Z direction and has an area that is one size larger than the areas of power storage module 4, conductive plate 5, and conductive plate 5B. When the end plate 8 has conductivity, an insulating plate B having electrical insulation properties is provided between the end plate 8 and the conductive plate 5B.

An insertion hole 8 a is provided at the edge of the end plate 8 at a position outside the module stack 2 . The fastening bolt 9 is passed from the insertion hole 8a of one end plate 8 toward the insertion hole 8a of the other end plate 8. A nut 10 is screwed onto the tip of the fastening bolt 9 protruding from the insertion hole 8a of the other end plate 8. Thereby, the power storage module 4, the conductive plate 5A, and the conductive plate 5B are sandwiched between the end plates 8, and are unitized as a module stack 2. Further, a restraining load is applied to the module stack 2 in the Z direction.

Next, the configuration of power storage module 4 will be explained in detail. FIG. 2 is a sectional view showing the internal configuration of the power storage module. As shown in FIG. 2, the electricity storage module 4 includes an electrode stack 11 and a resin sealing body 12 that seals the electrode stack 11. The power storage module 4 is formed, for example, in the shape of a rectangular parallelepiped.

The electrode stack 11 includes a plurality of electrodes stacked on each other in the stacking direction with a separator 13 in between, and current collector plates 20A and 20B disposed at the stacked ends of the electrode stack 11. The plurality of electrodes includes a stack of bipolar electrodes 14, a negative terminal electrode 18, and a positive terminal electrode 19. A stacked body of a plurality of bipolar electrodes 14 is provided between a negative terminal electrode 18 and a positive terminal electrode 19.

Bipolar electrode 14 includes a current collector plate 15 (third current collector plate) including one surface 15a and another surface 15b opposite to one surface 15a, a positive electrode 16 provided on one surface 15a, and a positive electrode 16 provided on the other surface 15b. The negative electrode 17 has a negative electrode 17 . The positive electrode 16 is a positive electrode active material layer formed by coating the current collector plate 15 with a positive electrode active material. The negative electrode 17 is a negative electrode active material layer formed by coating the current collector plate 15 with a negative electrode active material. In the electrode stack 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of another bipolar electrode 14 adjacent to it on one side in the Z direction with the separator 13 in between. In the electrode stack 11, the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of another bipolar electrode 14 adjacent to the other side in the Z direction with the separator 13 in between.

The negative terminal electrode 18 includes a current collector plate 15 (first current collector plate) and a negative electrode 17 provided on the other surface 15b of the current collector plate 15. The negative terminal electrode 18 is arranged at one end in the Z direction so that the other surface 15b faces the center of the electrode stack 11 in the Z direction. A current collecting plate 20A is further laminated on one side 15a of the current collecting plate 15 of the negative terminal electrode 18, and is connected to one conductive plate 5 (see FIG. 1) adjacent to the power storage module 4 via this current collecting plate 20A. electrically connected. The negative electrode 17 provided on the other surface 15b of the current collector plate 15 of the negative terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the Z direction with the separator 13 in between.

The positive terminal electrode 19 includes a current collector plate 15 (second current collector plate) and a positive electrode 16 provided on one surface 15a of the current collector plate 15. The positive terminal electrode 19 is arranged at the other end in the Z direction so that one surface 15a faces the center of the electrode stack 11 in the Z direction. A current collecting plate 20B is further laminated on the other surface 15b of the current collecting plate 15 of the positive terminal electrode 19, and is connected to the other conductive plate 5 adjacent to the power storage module 4 (see FIG. 1) via this current collecting plate 20B. electrically connected. The positive electrode 16 provided on one side 15a of the current collector plate 15 of the positive terminal electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the Z direction with the separator 13 in between.

The current collector plate 15 is, for example, a metal plate such as a nickel plate or a nickel-plated steel plate. As an example, the current collector plate 15 is a rectangular metal foil made of nickel. Each current collector plate 15 is one of the current collector plates included in the electrode stack 11. The edge 15c of the current collector plate 15 has a rectangular frame shape, and is an uncoated area where the positive electrode active material and the negative electrode active material are not coated. Examples of the positive electrode active material constituting the positive electrode 16 include nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode 17 include a hydrogen storage alloy. In this embodiment, the area where the negative electrode 17 is formed on the other side 15b of the current collector plate 15 is slightly larger than the area where the positive electrode 16 is formed on the one side 15a of the current collector plate 15. The electrode stack 11 includes a plurality of current collector plates 15, 20A, and 20B stacked on each other in the stacking direction.

The separator 13 is a member that separates the opposing positive electrode 16 and negative electrode 17 to prevent short circuits caused by contact between the two electrodes and allows charge carriers to pass therethrough, and is formed, for example, in a sheet shape. Examples of the separator 13 include porous films made of polyolefin resins such as polyethylene (PE) and polypropylene (PP), and woven or nonwoven fabrics made of polypropylene, methylcellulose, and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound. Note that the separator 13 is not limited to a sheet shape, but may be a bag shape.

The current collector plates 20A and 20B are substantially the same members as the current collector plate 15, and are metal plates such as nickel plates and nickel-plated steel plates, for example. Both current collector plates 20A and 20B are one of the current collector plates included in the electrode stack 11. As an example, the current collector plates 20A and 20B are rectangular metal foils made of nickel. The current collector plates 20A and 20B are uncoated electrodes in which neither the positive electrode active material layer nor the negative electrode active material layer is coated on one side 20a and the other side 20b.

The current collector plate 20A (fourth current collector plate) is a current collector located at one stacked end of the electrode stack 11. In other words, the current collector plate 20A constitutes one end portion of the electrode stack 11. Due to the current collector plate 20A, the negative terminal electrode 18 is placed between the current collector plate 20A and the bipolar electrode 14 along the Z direction. The current collector plate 20B is located at the other stacked end of the electrode stack 11. Due to the current collector plate 20B, the positive terminal electrode 19 is placed between the current collector plate 20B and the bipolar electrode 14 along the Z direction.

The sealing body 12 is made of, for example, an insulating resin and is formed into a rectangular cylindrical shape as a whole. The sealing body 12 is provided so as to surround the side surface 11a of the electrode stack 11. The sealing body 12 holds an edge 15c on the side surface 11a. The sealing body 12 is a plurality of frame-shaped parts provided at the edges of the current collector plates included in the electrode stack 11 (that is, the edge 15c of the current collector plate 15 and the edges 20c of the current collector plates 20A and 20B). a first sealing part 21 (a plurality of frames), and a second sealing part 22 that surrounds the first sealing part 21 from the outside along the side surface 11a and is coupled to each of the first sealing parts 21. It has The first sealing part 21 and the second sealing part 22 are made of, for example, an insulating resin having alkali resistance. Examples of the resin include polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE).

The first sealing portion 21 is continuously provided over the entire circumference of the edge 15c of the current collector plate 15 or the edge 20c of the current collector plates 20A and 20B, and has a rectangular frame shape when viewed from the Z direction. The first sealing part 21 is welded to the edge 15c of the current collector plate 15 or the edge 20c of the current collector plates 20A and 20B by, for example, ultrasonic waves or heat, and is airtightly joined. The first sealing portion 21 includes an outer portion 21a that protrudes outward from the edge of the current collector plate 15 or the current collector plates 20A, 20B, and an outer portion 21a located inside the edge of the current collector plate 15 or the current collector plates 20A, 20B. and an inner portion 21b. A welding layer 23 is provided at the tip (outer edge) of the outer portion 21 a of the first sealing portion 21 . The first sealing part 21 is joined to the second sealing part 22 via a welding layer 23. The welding layer 23 is formed by bonding the tips of the first sealing portions 21 that are melted by various welding methods such as hot plate welding, ultrasonic welding, and infrared welding.

The plurality of first sealing parts 21 include a plurality of first sealing parts 21A provided on the bipolar electrode 14 and the positive terminal electrode 19, a first sealing part 21B provided on the negative terminal electrode 18, and a current collector. It has a first sealing part 21C provided on the plate 20A and first sealing parts 21D and 21E provided on the current collector plate 20B.

The first sealing portion 21A is joined to one side 15a of the current collector plate 15 of the bipolar electrode 14 and the positive terminal electrode 19. The inner portion 21b of the first sealing portion 21A is located between the edges 15c of the current collector plates 15 that are adjacent to each other in the Z direction. The area where the edge 15c on one side 15a of the current collector plate 15 and the first sealing part 21A overlap when viewed from the Z direction is a bonding area between the current collector plate 15 and the first sealing part 21A. .

In this embodiment, the first sealing part 21A has a two-layer structure formed by folding one film into two. The outer edge of the first sealing part 21A joined to the second sealing part 22 is a folded part (bending part) of the film. The first layer of film constituting the first sealing portion 21A is bonded to one side 15a. The inner edge of the second layer film is located outside the inner edge of the first layer film, and forms a stepped portion on which the separator 13 is placed. The inner edge of the second layer film is located inside the edge of the current collector plate 15.

The first sealing portion 21B is joined to one side 15a of the current collector plate 15 of the negative terminal electrode 18. The inner portion 21b of the first sealing portion 21B is located between the edge 15c of the current collector plate 15 of the negative terminal electrode 18 that are adjacent to each other in the Z direction and the edge 20c of the current collector plate 20A. The area where the edge 15c on one side 15a of the current collector plate 15 and the inner portion 21b of the first sealing part 21B overlap is a bonding area between the current collector plate 15 and the first sealing part 21B. The first sealing portion 21B is also joined to the other surface 20b of the current collector plate 20A. The area where the edge 20c on the other surface 20b of the current collector plate 20A and the first sealing part 21B overlap is a joining area between the current collector plate 20A and the first sealing part 21B. In this embodiment, the first sealing part 21B is also joined to the edge 20c on the other surface 20b of the current collector plate 20A.

The first sealing portion 21C is joined to one surface 20a of the current collector plate 20A. In this embodiment, the first sealing part 21C is located closest to one end in the Z direction among the plurality of first sealing parts 21. The area where the edge 20c on one side 20a of the current collector plate 20A and the first sealing part 21C overlap is a joining area between the current collector plate 20A and the first sealing part 21C.

In this embodiment, the outer edges of the first sealing parts 21B and 21C joined to the second sealing part 22 are continuous. That is, the first sealing parts 21B and 21C are formed by folding one film into two with the edge 20c of the current collector plate 20A in between. The outer edge portions of the first sealing portions 21B and 21C are folded portions (bent portions) of the film. The films constituting the first sealing parts 21B and 21C are joined to the edge 20c on both one side 20a and the other side 20b of the current collector plate 20A. In this way, by joining both sides of the current collector plate 20A to the first sealing parts 21B and 21C, it is possible to suppress seepage of the electrolytic solution due to the so-called alkali creep phenomenon.

The first sealing portion 21D is joined to one side 20a of the current collector plate 20B. The inner portion 21b of the first sealing portion 21D is located between the edge 15c of the current collector plate 15 of the positive terminal electrode 19 and the edge 20c of the current collector plate 20B that are adjacent to each other in the Z direction. The area where the edge 20c on one surface 20a of the current collector plate 20B and the first sealing part 21D overlap is a bonding area between the current collector plate 20B and the first sealing part 21D.

The first sealing portion 21E is arranged at the edge 20c on the other surface 20b of the current collector plate 20B. In this embodiment, the first sealing part 21E is located at the other end side in the Z direction among the plurality of first sealing parts 21. Moreover, in this embodiment, the first sealing part 21E is not joined to the current collector plate 20B.

The current collector plate 20A located at the end of the stack has an exposed surface 20d exposed from the first sealing part 21. In this embodiment, the central region of one side 20a of the current collector plate 20A corresponds to the exposed surface 20d exposed from the first sealing part 21C. The other surface 20b of the current collector plate 20B has an exposed surface 20d exposed from the first sealing part 21E. The exposed surface 20d includes a contact area 20e (for example, see FIG. 10) that contacts (abuts) and is electrically connected to the conductive plate 5, and a non-contact area 20f (for example, (see FIG. 10).

In this embodiment, the outer edges of the first sealing parts 21D and 21E joined to the second sealing part 22 are continuous. That is, the first sealing parts 21D and 21E are formed by folding one film into two with the edge 20c of the current collector plate 20B in between. The outer edges of the first sealing parts 21D and 21E are folded parts (bent parts) of the film. The films constituting the first sealing parts 21D and 21E are joined to the edge 20c on one side 20a of the current collector plate 20B.

In the bonding region, the surfaces of current collector plates 15, 20A, 20B are roughened. The roughened area may be only the bonding area, but in this embodiment, the entire one side 15a of the current collector plate 15 is roughened. Moreover, the entire one side 20a and the other side 20b of the current collector plate 20A are roughened. Further, the entire one side 20a of the current collector plate 20B is roughened. For example, the exposed surface 20d included in one side 20a of the current collector plate 20A may be roughened by forming a plurality of protruding platings, or may be roughened by being subjected to a rubbing treatment or the like. good.

The surface roughening of the current collector plate 20A can be achieved, for example, by electrolytically plating the current collector plate to form a plurality of fine protrusions on its surface. By forming a plurality of fine protrusions in the bonding region, the resin that has become molten during the bonding process is melted at the bonding interface between each of the current collector plates 15A, 20A, and 20B and the first sealing portion 21 in the bonding region. It gets into between the multiple fine protrusions formed by roughening the surface. Then, the resin cools and solidifies while being stuck between the plurality of fine protrusions. For this reason, the anchor effect is exerted and the first sealing part 21 made of resin is prevented from peeling off from each of the current collector plates 15A, 20A, and 20B. Thereby, the bonding strength between the current collector plates 15, 20A, 20B and the first sealing part 21 can be improved. The projections formed during surface roughening have, for example, a shape that becomes thicker from the proximal end toward the distal end. As a result, the cross-sectional shape between adjacent protrusions becomes an undercut shape, making it possible to enhance the anchoring effect. In addition, the frictional force between the contact area 20e of the exposed surface 20d and the conductive plate 5 that contacts the contact area 20e is increased.

The second sealing part 22 is provided outside the electrode stack 11 and the first sealing part 21 so as to surround the side surface 11a of the electrode stack 11, and constitutes an outer wall (housing) of the power storage module 4. . The second sealing portion 22 is formed, for example, by injection molding of resin, and extends over the entire length of the electrode stack 11 along the Z direction. The second sealing portion 22 has a rectangular frame shape extending in the Z direction as an axial direction. The second sealing portion 22 is integrated with, for example, a portion of the first sealing portion 21 that is melted by heat during injection molding.

The sealing body 12 forms an internal space V between adjacent electrodes and also seals the internal space V. More specifically, the second sealing part 22, together with the first sealing part 21, connects between the bipolar electrodes 14 adjacent to each other along the Z direction, and between the negative terminal electrodes 18 and the bipolar electrodes adjacent to each other along the Z direction. The positive terminal electrode 19 and the bipolar electrode 14, which are adjacent to each other along the Z direction, are sealed. As a result, airtightly partitioned internal spaces V are formed between adjacent bipolar electrodes 14, between the negative terminal electrode 18 and the bipolar electrode 14, and between the positive terminal electrode 19 and the bipolar electrode 14. ing. This internal space V accommodates an electrolytic solution (not shown) containing an alkaline solution such as an aqueous potassium hydroxide solution. The electrolytic solution is impregnated into the separator 13, the positive electrode 16, and the negative electrode 17. The sealing body 12 also seals between the current collector plate 20A and the negative terminal electrode 18 and between the current collector plate 20B and the positive terminal electrode 19, respectively.

Next, the detailed structure of the conductive plate 5 mentioned above will be explained. FIG. 3 is a plan view showing the power storage module 4 and the conductive plate 5A on the power storage module 4. As shown in FIG. 3, the conductive plate 5A has a rectangular shape having an area slightly smaller than the planar shape of the power storage module 4 when viewed from the Z direction (that is, in plan view). The conductive plate 5A is located within the frame of the second sealing part 22. In this embodiment, the conductive plate 5A has a rectangular shape including a pair of long sides 5b and 5c and a pair of short sides 5d and 5e. A pair of long sides 5b and 5c extend along the X direction and face each other in the Y direction. A pair of short sides 5d and 5e extend along the Y direction and face each other in the X direction.

In this embodiment, the pair of long sides 5b and 5c and the pair of short sides 5d and 5e constitute the outer edge of the conductive plate 5A. The pair of long sides 5b and 5c overlap with the first sealing part 21 when viewed from the Z direction. The pair of short sides 5d and 5e do not overlap with the first sealing part 21 when viewed from the Z direction. When viewed from the Z direction, the first sealing part 21 disposed on the pair of short sides 5d and 5e is smaller than the first sealing part 21 disposed on the pair of long sides 5b and 5c. It is provided on the inside. The length in the X direction of the first sealing part 21 disposed on the pair of short sides 5d and 5e is the Y length of the first sealing part 21 disposed on the pair of long sides 5b and 5c. longer than the length in the direction.

The conductive plate 5A further includes one surface 5f in the thickness direction (Z direction) and the other surface 5g (see FIG. 8(a)). One surface 5f comes into contact with current collector plate 20B arranged at the stacked end of adjacent power storage modules 4 on one side in the Z direction. The other surface 5g comes into contact with a current collector plate 20A disposed at the stacked end of adjacent power storage modules 4 on the other side in the Z direction. As described above, in the electrode stack 11, the central region of the electrode stack 11 swells in the Z direction compared to the surrounding area. Therefore, the central regions of one surface 5f and the other surface 5g are in contact with the central regions of one surface 20a of current collector plate 20A and the other surface 20b of current collector plate 20B. The conductive plate 5A is arranged in contact with the current collecting plates 20A and 20B arranged at the stacked ends of the adjacent power storage modules 4, and electrically connects the plurality of power storage modules 4 in series.

A detection element 70 is connected to each end face of the conductive plate 5A in the X direction. The detection element 70 is a sensor that monitors the state of the power storage module 4 and includes, for example, an element that detects the temperature of the power storage module 4 and an element that detects the voltage output from the power storage module 4. The detection element 70 is made of an insulating resin having alkali resistance, such as polypropylene (PP), and has the same thickness as the conductive plate 5A.

The conductive plate 5A includes a plurality of (four in this embodiment) plate-like members 50 arranged along the X direction and connected to each other. Each plate member 50 has a rectangular shape when viewed from the Z direction (that is, when viewed from above). In this embodiment, each plate member 50 has a rectangular shape including a pair of long sides along the Y direction and a pair of short sides along the X direction when viewed from the Z direction. The plate members 50 are arranged along the X direction such that the long sides of adjacent plate members 50 face each other in the X direction.

The plate member 50 includes one surface 50a and the other surface 50b in the thickness direction (Z direction). One side 50a constitutes a part of one side 5f. The other surface 50b constitutes a part of the other surface 5g.

The plate member 50 further includes a pair of end surfaces 50c and 50d facing each other in the X direction, and a pair of end surfaces 50e and 50f facing each other in the Y direction. Each of the end surface 50c and the end surface 50d is a flat surface including the long sides of the plate member 50, and extends along the YZ plane. Each of the end surface 50c and the end surface 50d extends along the Y direction. The end surface 50c is located on the short side 5d side in the X direction, and the end surface 50d is located on the short side 5e side in the X direction. What is the end face 50c of one plate-like member 50 (first plate-like member) of the two plate-like members 50 adjacent to each other in the X direction and the end face 50d of the other plate-like member 50 (second plate-like member)? , facing each other in the X direction. In other words, one plate member 50 has an end surface 50c (second end surface) facing the other plate member 50 in the X direction, and the other plate member 50 has an end surface 50c (second end surface) opposite to the other plate member 50 in the It has an end surface 50d (first end surface) opposite to 50.

Each of the end surface 50e and the end surface 50f is a flat surface including the short side of the plate member 50, and extends along the XZ plane. Each of the end surface 50e and the end surface 50f extends along the X direction. The end surface 50e is located on the long side 5b side, and connects one end of the end surface 50c and the end surface 50d in the Y direction. The end surface 50f is located on the long side 5c side, and connects the other ends of the end surface 50c and the end surface 50d in the Y direction. In each plate member 50, the positions of the end faces 50e in the Y direction are aligned with each other, and the positions of the end faces 50f in the Y direction are aligned with each other.

The plurality of plate-like members 50 are composed of a plurality of (three in this embodiment) plate-like members 50A and one plate-like member 50B. In this embodiment, the plate-like member 50B is arranged closer to the short side 5d than the plurality of plate-like members 50A. The end surface 50c of the plate member 50B disposed closest to the short side 5d constitutes the short side 5d of the conductive plate 5A. An end surface 50d of the plate member 50A disposed closest to the short side 5e constitutes the short side 5e of the conductive plate 5A.

FIG. 4 is a perspective view of the plate member 50A of the conductive plate 5A. FIG. 5 is a perspective view of the plate member 50B of the conductive plate 5A. As shown in FIGS. 4 and 5, the plurality of through holes 5a described above are formed in the plate members 50A and 50B. The through holes 5a penetrate through the inside of the plate member 50 in the Y direction from the end surface 50e to the end surface 50f of the plate members 50A and 50B, and are arranged along the X direction. The cross-sectional shape of each through hole 5a is, for example, a rectangle whose longitudinal direction is the X direction when viewed from the Y direction. A cooling fluid F flows through each through hole 5a. The cooling fluid F flowing through each through hole 5a, for example, heads from the end surface 50e of the plate-shaped members 50A, 50B toward the end surface 50f in the Y direction.

As shown in FIG. 4, the plate-like member 50A has a convex portion 61 provided on the end surface 50d and a recessed portion 62 provided on the end surface 50c. The convex portion 61 and the concave portion 62 are formed to fit into each other. The convex portion 61 extends from one end in the Y direction to the other end of the end surface 50d of the plate member 50A, and has the same XZ cross-sectional shape from one end to the other end of the end surface 50d in the Y direction. That is, the XZ cross-sectional shape of the convex portion 61 is uniform in the Y direction. The convex portion 61 extends (projects) linearly along the X direction from the center of the end surface 50d of the plate member 50A in the Z direction.

The recess 62 extends from one end of the end surface 50c in the Y direction to the other end, and has the same XZ cross-sectional shape from one end of the end surface 50c in the Y direction to the other end. In other words, the XZ cross-sectional shape of the recess 62 is uniform in the Y direction. The bottom of the recess 62 in the X direction is constituted by the end surface 50c (second end surface). The recessed portion 62 has a pair of wall portions 62a that protrude linearly along the X direction from each of both ends of the end surface 50c in the Z direction. The tip of each wall portion 62a has a chamfered shape (R shape or rounded shape). Each of the pair of wall portions 62a has a base portion 62b protruding from the end surface 50c in the X direction, and a tip portion 62c protruding from the base portion 62b in the X direction. In the recessed portion 62, the distance between the base portions 62b along the Z direction is constant. On the other hand, in the recessed portion 62, the distance between the tip portions 62c along the Z direction is not constant. Specifically, in the recess 62, the distance between the tips 62c along the Z direction increases as the distance approaches the tip of the wall 62a in the X direction. The distance between the tips 62c along the Z direction may change continuously or in steps. In this embodiment, from the viewpoint of preventing the convex portion 61 from getting caught, the distance between the tip portions 62c along the Z direction changes continuously. Therefore, when viewed from the Y direction, the portion of the inner surface of the recess 62 formed by each tip 62c becomes an inclined surface toward one side 50a or the other side 50b as it approaches the tip of the wall 62a. On the other hand, when viewed from the Y direction, the portion of the inner surface of the recess 62 formed by the base 62b becomes a plane along the XY plane.

Two plate members 50A adjacent to each other in the X direction are connected to each other by the convex portion 61 of one plate member 50A and the recess 62 of the other plate member 50A fitting into each other to form a connecting portion 60. (See FIGS. 8(a) and 8(b)). In this embodiment, the connecting portion 60 includes a convex portion 61 that is a convex connecting portion that protrudes from one plate-like member 50A toward the other plate-like member 50A in the X direction, and It has a concave portion 62 which is a concave connecting portion that is concave in the direction and accommodates the convex portion 61 . That is, in this embodiment, the connecting portion 60 is constituted by a part of one plate-like member 50A and a part of the other plate-like member 50A. Two plate members 50A adjacent to each other in the X direction are rotatably connected to each other via a connecting portion 60 having a convex portion 61 and a concave portion 62. In this embodiment, two adjacent plate members 50A are in contact with each other at the connecting portion 60. In addition, according to FIGS. 8A and 8B, the convex portion 61 and the concave portion 62 are not in contact with each other in the Z direction, but the present invention is not limited to this.

In this embodiment, the protrusion length L1 of the convex portion 61 in the X direction is shorter than the depth L2 of the concave portion 62 in the X direction. In other words, the protrusion length L1 of the convex portion 61 in the X direction is shorter than the protrusion length of the wall portion 62a of the recess 62 in the X direction. Therefore, when two plate-like members 50A adjacent to each other in the X direction are connected, the recess 62 of the other plate-like member 50A contacts one of the plate-like members 50A (Figs. )reference). Specifically, the recess 62 of the other plate-like member 50A contacts the end surface 50d of the one plate-like member 50A. More specifically, the tip portions 62c included in each of the pair of wall portions 62a of the recess 62 of the other plate-like member 50A abut against the end surface 50d of the one plate-like member 50A.

As shown in FIG. 5, the plate member 50B differs from the plate member 50A (see FIG. 4) in that it has a protrusion 61 on the end surface 50c instead of a recess 62 (see FIG. 4). , is the same as the plate member 50A in other respects. The plate member 50A and the plate member 50B that are adjacent to each other in the X direction are connected to each other by the concave portion 62 of the plate member 50A and the convex portion 61 of the plate member 50B fitting into each other to form a connecting portion 60. ing.

By connecting the plate members 50A and 50B, a plurality of (three in this embodiment) contact portions CP are formed on each one side 5f and the other side 5g of the conductive plate 5A. The contact portion CP is formed by two plate members 50A adjacent to each other and by plate members 50A and 50B adjacent to each other. The contact portion CP extends in the Y direction along the end surface 50d. In this embodiment, the two plate-like members 50A that are adjacent to each other are formed by the end face 50d of one of the plate-like members 50A and the tip 62c of the recess 62 of the other plate-like member 50A. The two plate-like members 50A and 50B that are adjacent to each other are formed by the end face 50d of the plate-like member 50B and the tip 62c of the recess 62 of the plate-like member 50A.

FIG. 6 is a perspective view of the detection element. Although FIG. 6 shows the detection element 70 connected to the short side 5d of the conductive plate 5A, the detection element 70 connected to the short side 5e of the conductive plate 5A also has a similar configuration. . As shown in FIG. 6, the detection element 70 has, for example, a rectangular shape when viewed from the Z direction (that is, when viewed from above). In this embodiment, the detection element 70 has a rectangular shape including a pair of long sides along the Y direction and a pair of short sides along the X direction when viewed from the Z direction. The detection element 70 includes one surface 70a and the other surface 70b in the thickness direction (Z direction). One side 70a is, for example, coplanar with one side 5f. The other surface 70b is, for example, coplanar with the other surface 5g.

The detection element 70 further includes a pair of end surfaces 70c and 70d facing each other in the X direction, and a pair of end surfaces 70e and 70f facing each other in the Y direction. Each of the end surface 70c and the end surface 70d is a flat surface including the long side of the detection element 70, and extends along the YZ plane. Each of the end surface 70c and the end surface 70d extends along the Y direction. The end surface 70c is located on the conductive plate 5 side, and the end surface 70d is located on the opposite side of the conductive plate 5.

Each of the end surface 70e and the end surface 70f is a flat surface including the short side of the detection element 70, and extends along the XZ plane. Each of the end surface 70e and the end surface 70f extends along the X direction. The end surface 70e is located on the long side 5b side, and the end surface 70f is located on the long side 5c side. The end surface 70e is, for example, coplanar with each end surface 50e. For example, the end surface 70f forms the same plane as each end surface 50f.

The detection element 70 has a recess 62 on the end surface 70c. In the detection element 70 on the short side 5d side of the conductive plate 5A, the plate member 50B adjacent in the X direction, the recess 62 of the detection element 70 and the protrusion 61 of the plate member 50B fit into each other to form a connecting part 60. They are connected by doing this. In the detection element 70 on the short side 5e side of the conductive plate 5A, the plate member 50A adjacent in the X direction, the recess 62 of the detection element 70, and the protrusion 61 of the plate member 50A fit into each other to form a connecting portion 60. They are connected by doing this.

Although not shown, the conductive plate 5B is made of a single plate-like member. When viewed from the Z direction, the conductive plate 5B has, for example, a rectangular shape having the same area as the planar shape of the connected body in which the conductive plate 5A and the pair of detection elements 70 are connected, and the conductive plate 5B has a rectangular shape that has the same area as the planar shape of the connected body in which the conductive plate 5A and the pair of detection elements 70 are connected. placed within.

Next, the aforementioned seal member 80 (see FIG. 7) will be explained. The seal member 80 is made of resin, for example. The seal member 80 is made of, for example, a material that does not contain low molecular weight siloxane. In this case, relay contact failure is suppressed. The seal member 80 is made of, for example, a material that is difficult to hydrolyze. In this case, a decrease in adhesive strength due to moisture is suppressed. The seal member 80 is made of modified silicone, for example. The seal member 80 is, for example, a liquid gasket. In this embodiment, the seal member 80 is made of insulating resin, but may be made of conductive resin. Seal member 80 is provided between conductive plate 5 and power storage module 4. The sealing member 80 is provided between the conductive plate 5 and the current collecting plates 20A and 20B at the stacked end of the power storage module 4, and joins (adheres) these to each other. The module stack 2 shown in FIG. 1 is formed, for example, by stacking the conductive plate 5 and the power storage module 4 in order from the bottom. The sealing member 80 is provided between the conductive plate 5 and the power storage module 4 in a liquid state before hardening when the conductive plate 5 and the power storage module 4 are stacked. Thereby, the sealing member 80 can be made to follow the undulations and irregularities of the surface. The sealing member 80 is applied by, for example, a dispenser.

Specifically, first, the sealing member 80 is provided at a predetermined position on the conductive plate 5B arranged at the stacking position, and then the power storage module 4 is stacked on the conductive plate 5B, and the conductive plate 5B and the power storage module 4 are sealed. They are joined by a member 80. Subsequently, after providing a seal member 80 at a predetermined position on the power storage module 4, the conductive plate 5A is laminated on the power storage module 4, and the power storage module 4 and the conductive plate 5A are bonded together by the seal member 80. At this time, the conductive plate 5A is laminated on the power storage module 4 in a state where the plurality of plate members 50 included in the conductive plate 5A are integrated. For example, the plurality of plate-like members 50 are integrated by sandwiching the plurality of plate-like members 50 along the X direction. Similarly, the process of sequentially stacking the power storage module 4 and the conductive plate 5A is repeated while providing the seal member 80 at a predetermined position. Finally, after providing a seal member 80 at a predetermined position on the uppermost power storage module 4, the conductive plate 5B is laminated on the power storage module 4, and the power storage module 4 and the conductive plate 5B are joined by the seal member 80. After all of the conductive plates 5 and power storage modules 4 are laminated, the sealing member 80 is hardened to form the module laminate 2. When stacking the conductive plate 5 and the power storage module 4, since the sealing member 80 is liquid, surface pressure is hardly applied to the conductive plate 5 and the power storage module 4. Therefore, as the seal member 80, a liquid seal is selected that takes a long time to harden and does not harden during the lamination process.

FIG. 7 is a plan view for explaining the position where the seal member 80 is provided. In FIG. 7, in the above-described method of forming a module stack 2, a sealing member 80 provided on the electricity storage modules 4 other than the uppermost stage (in the module stack 2, a sealing member 80 (in the module stack 2, a sealing member 80) (corresponding to the sealing member 80 provided therebetween) is shown. The sealing member 80 is attached to the inner edge of the first sealing part 21 so as to be in contact with the first sealing part 21 provided on the edge 20c of the current collecting plate 20A on the exposed surface 20d of one side 20a of the current collecting plate 20A. 21c, and a plurality of seals (in this embodiment, three seals) are provided along the connecting portion 60 (see FIG. 3) formed between the adjacent plate members 50. ) and a second seal portion 80b.

The first seal portion 80a has, for example, a rectangular ring shape, and is continuously provided around the entire circumference of the first sealing portion 21. The first seal portion 80a airtightly seals between the power storage module 4 and the conductive plate 5. The second seal portion 80b is provided extending along the Y direction. Both ends of the second seal portion 80b are connected to the first seal portion 80a. The second seal portion 80b airtightly seals the adjacent plate members 50.

Although not shown, in the method for forming the module laminate 2 described above, a sealing member 80 provided on the conductive plate 5A (in the module laminate 2, between the conductive plate 5A and the current collector plate 20B of the power storage module 4) (corresponding to the seal member 80 provided) is provided in the same manner as the seal member 80 provided on the electricity storage modules 4 other than the top stage. Further, a sealing member 80 provided on the uppermost power storage module 4 (corresponding to the sealing member 80 provided between the conductive plate 5B and the current collecting plate 20A of the power storage module 4 in the module stack 2), and the conductive The seal member 80 provided on the plate 5B (corresponding to the seal member 80 provided between the conductive plate 5B and the current collecting plate 20B of the power storage module 4 in the module stacked body 2) is such that the conductive plate 5B is one plate. Since it is made of a shaped member, it does not include the second seal portion 80b.

With reference to FIGS. 8(a) and 8(b), a method of sealing between the plate-like members 50A using the second seal portion 80b will be described. FIG. 8A shows a state in which the second seal portion 80b is provided on the power storage module 4. The second seal portion 80b is provided corresponding to the contact portion CP. The contact portions CP are formed at both ends of the connecting portion 60 in the Z direction. The second seal portion 80b is provided corresponding to the contact portion CP on the current collector plate 20A side (on the other surface 5g side). The second seal portion 80b is provided so as to overlap the contact portion CP on the current collector plate 20A side when viewed from the Z direction. In this embodiment, the end portion of the end surface 50d in the Z direction has a chamfered shape (R shape or rounded shape). Furthermore, as described above, the tip of the wall portion 62a also has a chamfered shape. Therefore, a groove GR is formed outside the contact portion CP in the Z direction by the end portion of the end surface 50d and the tip of the wall portion 62a. The groove GR overlaps the contact portion CP in the Z direction.

FIG. 8(b) shows a state after the conductive plate 5A is laminated on the power storage module 4. As shown in FIG. 8(b), the second seal portion 80b enters the groove GR when the conductive plate 5A is stacked on the current collector plate 20A. This seals the contact portion CP. If a gap exists in the contact portion CP, the seal member 80 may be guided into the recess 62 forming the contact portion CP via the gap. In this case, the second seal portion 80b is prevented from spreading more than necessary on the current collector plate 20A and reducing conductivity. In the exposed surface 20d of the one side 20a of the current collector plate 20A, the portion where the second seal portion 80b is present becomes the non-contact area 20f. Although not shown, when the seal member 80 is provided on the conductive plate 5A, the second seal portion 80b is provided on another contact portion CP. Since another groove GR is formed on the outside of another contact portion CP, the second seal portion 80b can be easily provided. After providing the sealing member 80 on the conductive plate 5A, by stacking the electricity storage modules 4, the mutually adjacent plate-like members 50A are hermetically sealed by the second sealing portion 80b.

With reference to FIG. 9, a method of sealing between the power storage module 4 and the conductive plate 5A using the first seal portion 80a will be described. In FIG. 9, a state in which a conductive plate 5A and a detection element 70 are stacked on the power storage module 4 is shown. As shown in FIG. 9, the conductive plate 5A and the detection element 70 are connected to each other. As described above, the short sides 5d and 5e (see FIG. 3) of the conductive plate 5A to which the detection element 70 is connected do not overlap the first sealing part 21 when viewed from the Z direction. As shown in FIG. 9, the first seal portion 80a corresponds to the connection portion 60 formed between the detection element 70 and the conductive plate 5A from the inner edge 21c of the first sealing portion 21 in the current collector plate 20A. It extends to the position and is joined to the conductive plate 5A. The first seal portion 80a is adhered to the conductive plate 5A and the non-contact area 20f, is filled between the conductive plate 5A and the non-contact area 20f, and is airtight between the conductive plate 5A and the exposed surface 20d. It's sealed.

The sealing member 80 is made of modified silicone, for example, but modified silicone does not adhere to polyolefin plastic materials such as polypropylene (PP), which have low surface free energy (polarity). In other words, the sealing member 80 made of modified silicon does not bond to the detection element 70 made of such a resin material. Note that the adhesion by the sealing member 80 is realized by an anchor effect caused by the sealing member 80 biting into the unevenness of the surface and physical interaction (intermolecular force).

The first seal portion 80a may have a wet and spread shape on the current collector plate 20A by laminating the conductive plate 5A and the detection element 70 on the current collector plate 20A, or may have a wet and spread shape in advance. It may be applied onto the current collector plate 20A. The first seal portion 80a enters the groove GR located outside the contact portion CP, thereby suppressing the first seal portion 80a from spreading more than necessary on the current collector plate 20A and reducing conductivity. Ru.

As described above, in the power storage device 1, the conductive plates 5A are arranged in the X direction perpendicular to the Z direction, are connected to each other by the connecting portions 60, and have a plurality of plate-like members 50A in contact with the exposed surface 20d. have Thereby, by adjusting the number of plate-like members 50A included in the conductive plate 5A, the dimension of the conductive plate 5A in the X direction can be easily adjusted. Therefore, the shape of the conductive plate 5A can be made to follow the shape of the exposed surface 20d of the power storage module 4, compared to the case where the conductive plate is composed of one plate-like member. Furthermore, in the connecting portion 60 having a convex portion 61 that is a convex connecting portion and a recess 62 that is a concave connecting portion that accommodates the convex portion 61, first plates adjacent to each other among the plurality of plate members 50A The shaped member 50A and the second plate shaped member 50A are in contact with each other. Specifically, the recess 62 of the second plate member 50A contacts the first plate member 50A. Thereby, by sandwiching the conductive plate 5A along the X direction, the plurality of plate-like members 50A can be integrated and transported. Thereby, positioning, transportation, etc. of each plate member 50A in the electricity storage module 4 can be facilitated. Therefore, according to the present embodiment, it is possible to provide the power storage device 1 having the conductive plate 5A that can ensure followability to the exposed surface 20d of the power storage module 4 and can suppress deterioration of assemblability during manufacturing.

In addition, in the present embodiment, in the conductive plate 5A, two adjacent plate members 50 are rotatably connected to each other at a connecting portion 60. In this case, the rotation of the plate member 50 allows the shape of the conductive plate 5A to follow the shape of the exposed surface 20d of the power storage module 4 well. Furthermore, the conductive plate has a cooling function because the cooling fluid F flows through each through hole 5a. In addition, when the power storage module 4 expands due to the provision of the connecting portion 60, the current collector plate 20A provided at the outermost side of the electrode stack is connected to the first plate member 50A and the second plate member 50A, which are adjacent to each other. The connecting portion 60 is provided with a slope that prevents the connecting portion 60 from entering between the connecting portion 60 and the plate-like member 50A. Thereby, damage to the exposed surface 20d when the power storage module 4 expands can be suppressed.

In this embodiment, in the first plate member 50A and the second plate member 50A that are adjacent to each other among the plurality of plate members 50A, the first plate member 50A faces the second plate member 50A in the X direction. The convex portion 61 protrudes from the end surface 50d toward the second plate member 50A, and the recess 62 of the second plate member 50A contacts the end surface 50d. Therefore, it is possible to suppress the generation of a gap between the end surface 50d of the first plate member 50A and the recess 62 of the connecting portion 60. Thereby, when internal pressure is generated in the power storage module 4, for example, it is possible to suppress the current collector plate 20A of the power storage module 4 from entering the gap. Further, even if the gap occurs, the gap can be reliably filled with the second seal portion 80b.

In this embodiment, the protrusion length L1 of the convex portion 61 in the X direction is shorter than the depth L2 of the concave portion 62 in the X direction. Therefore, it is possible to prevent the convex portion 61 from interfering with the contact between the concave portion 62 and the first plate member 50A along the X direction.

In this embodiment, the recess 62 has a pair of walls 62a that protrude in the X direction from each of both ends of the plate member 50A in the Z direction, and each of the pair of walls 62a has a base 62b and a base 62b. 62b and a distal end portion 62c protruding in the X direction, and the distance between the distal end portions 62c in the Z direction increases as the distance between the distal end portions 62c approaches the distal end of the wall portion 62a in the X direction. Therefore, the convex portion 61 is easily accommodated in the concave portion 62.

In this embodiment, in the first plate member 50A and the second plate member 50A that are adjacent to each other among the plurality of plate members 50A, the first plate member 50A has a convex portion 61, and the second plate member 50A has a recess 62. Therefore, the number of parts of the conductive plate 5A can be reduced.

Each modification of the above embodiment will be described below with reference to FIGS. 10 and 11. In each of the following modified examples, explanations of parts that overlap with the above embodiment will be omitted. Therefore, in the following, parts that are different from the above embodiment will be mainly explained.

FIG. 10 is a schematic cross-sectional view showing a part of the power storage module according to the first modification. As shown in FIG. 10, at least a portion of the concave portion 62 is curved toward and in contact with the convex portion 61 in the Z direction. In the first modification, a pair of wall portions 62a of the recess 62 sandwich the protrusion 61 in the Z direction. In other words, the concave portion 62 is caulked so as to sandwich the convex portion 61 . Therefore, one wall portion 62a, the convex portion 61, and the other wall portion 62a, which overlap in order in the Z direction, are integrated with each other. For example, after the convex portion 61 and the concave portion 62 are fitted, each wall portion 62a is brought into contact with the convex portion 61 by curving each wall portion 62a at each base portion 62b. The wall portion 62a may be curved using a tool or the like before the conductive plate 5A and the power storage module 4 are laminated, or may be curved when the conductive plate 5A and the power storage module 4 are laminated, or may be curved using a restraining member. The module laminate 2 may be curved when restrained by the module 3. From the viewpoint of stabilizing the transportation of the conductive plate 5A, the wall portion 62a may be curved before the conductive plate 5A and the power storage module 4 are stacked. From the viewpoint of simplifying the manufacturing process of the power storage device 1, the wall portion 62a may be curved when the conductive plate 5A and the power storage module 4 are stacked, or may be curved when the module stack 2 is restrained by the restraining member 3. Good too.

Also in the first modified example described above, the same effects as in the above embodiment are achieved. In addition, according to the first modification, each wall portion 62a of the recess 62 in the connecting portion 60 and the convex portion 61 are integrated. Thereby, when a force along the Z direction is applied to one wall 62a of the recess 62, the force is well transmitted to the protrusion 61 and the other wall 62a. Therefore, compression of the plate member 50 along the Z direction is suppressed at the connecting portion 60. Therefore, the connecting portion 60 can function as a reinforcing portion that reinforces the strength of the conductive plate 5A along the Z direction.

In addition, by sandwiching the convex portion 61 between the wall portions 62a before stacking the conductive plate 5A and the power storage module 4, two adjacent plate-like members 50 can be firmly connected to each other. Therefore, it becomes easier to integrate and transport the plurality of plate-like members 50A. Therefore, the positioning, transportation, etc. of each plate member 50A in the power storage module 4 can be further facilitated.

FIG. 11(a) is a schematic cross-sectional view showing a part of a power storage module according to a second modification. As shown in FIG. 11(a), in two plate-like members 50C included in the conductive plate 5C and adjacent to each other, the convex portion 61A of one plate-like member 50C (first plate-like member) is different from that of the other plate-like member. It contacts the end surface 50c (second end surface) that constitutes the bottom of the recess 62A of the plate-like member 50C (second plate-like member). In the second modification, the protrusion length L11 of the convex portion 61A in the X direction is longer than the depth L12 of the concave portion 62A in the X direction. Therefore, in the connecting portion 60A including the convex portion 61A and the recessed portion 62A, a gap G is formed between the end surface 50d (first end surface) of one plate member 50C and the tip of the recessed portion 62A.

FIG. 11(b) is a schematic cross-sectional view showing a state in which the plate-like members are sealed by the second seal portion. FIG. 11(b) shows a state after the conductive plate 5C is laminated on the power storage module 4. As shown in FIG. 11(b), when the conductive plate 5C is stacked on the current collector plate 20A, the second seal portion 80b enters the gap G between the connecting portions 60A and between the two plate-like members 50C. Seal the gap. The seal member 80 is guided into the gap G on the current collector plate 20A side along the end surface 50d and the chamfered shape of the tip of the wall portion 62a. The gap G on the current collector plate 20A side is closed by the second seal portion 80b. Further, by the second seal portion 80b entering the gap G, the second seal portion 80b is prevented from spreading more than necessary on the current collector plate 20A and reducing the conductivity.

Also in the second modification described above, the same effects as in the embodiment described above are achieved. In addition, as described above, by the seal member 80 entering the gap G of the connecting portion 60A, the seal member 80 becomes difficult to spread between the conductive plate 5C and the current collector plate 20A. Therefore, an increase in contact resistance between the conductive plate 5C and the power storage module 4 due to the seal member 80 can be suppressed.

In the second modification, the protrusion length L11 of the convex portion 61A in the X direction is longer than the depth L12 of the concave portion 62A in the X direction. Therefore, the recess 62A can be prevented from interfering with the contact between the protrusion 61A and the plate member 50C along the X direction.

The above embodiment and each modification example explain one aspect of the present disclosure. Therefore, the present disclosure can be modified without being limited to the embodiments and modifications described above. Moreover, the above embodiment and the above modification may be combined as appropriate. For example, the first modified example and the second modified example may be combined with each other.

In the above embodiment and the above modification, when viewed from the Z direction, the first sealing portion overlaps a pair of long sides that constitute a part of the outer edge of the conductive plate; It may also overlap with a pair of short sides constituting other parts of the outer edge. In this case, damage to the current collector plate due to contact with the pair of short sides of the conductive plate can also be suppressed. Furthermore, in this case, since the first sealing part is provided on the current collector plate at a position corresponding to the connection part between the detection element and the conductive plate, there is no need to provide a sealing member at this position.

In the above embodiment and the above modification, the protruding length of the convex portion of the plate-like member 50A or 50C and the protruding length of the convex portion of the plate-like member 50B may be different from each other. For example, the protruding length of the convex portion of the plate-like member 50B may be longer than the protruding length of the convex portion of the plate-like member 50A or 50C. In this case, for example, in two plate-shaped members 50A adjacent to each other, the recess of one plate-shaped member 50A contacts the end surface of the other plate-shaped member 50A, and the plate-shaped members 50A and In the member 50B, the convex portion of the plate-like member 50B may come into contact with the end surface of the plate-like member 50A.

In the above embodiment and the above modification, the current collector plate constituting one end of the plurality of current collector plates included in the electrode stack (i.e., the current collector disposed at the stacked end of the electrode stack) is the positive electrode. It may be a current collector plate included in the terminal electrode or a current collector plate included in the negative terminal electrode. Alternatively, the current collector plate may be a different member from the plurality of current collector plates included in the electrode stack.

DESCRIPTION OF SYMBOLS 1... Power storage device, 4... Energy storage module, 5, 5A, 5B, 5C... Conductive plate, 5b, 5c... Long side (outer edge), 5d, 5e... Short side (outer edge), 11... Electrode laminate, 11a... Side surface , 12... Sealing body, 14... Bipolar electrode, 15... Current collector plate, 15a... One side, 15b... Other side, 16... Positive electrode, 17... Negative electrode, 18... Negative terminal electrode, 19... Positive terminal electrode, 20A, 20B...Current plate, 20a...One side, 20b...Other side, 20c...Edge, 20d...Exposed surface, 20e...Contact area, 20f...Non-contact area, 21, 21A, 21B, 21C, 21D, 21E...th 1 sealing part (frame body), 21c...inner edge, 50, 50A, 50B, 50C... plate-like member (first plate-like member, second plate-like member), 60... connecting part, 70... detection element, 80... Seal member, V...Inner space.

Claims (10)

A power storage device comprising a power storage module and a conductive plate laminated on the power storage module in a first direction,
The electricity storage module is
an electrode stack having a plurality of current collector plates stacked on each other in the first direction;
a sealing body provided so as to surround the side surface of the electrode laminate;
The plurality of current collecting plates are:
a first current collector plate included in the negative terminal electrode;
a second current collector plate included in the positive terminal electrode;
a third current collector plate included in each of the plurality of bipolar electrodes provided between the negative terminal electrode and the positive terminal electrode,
A current collector plate disposed at a stacked end of the electrode stack has an exposed surface exposed from the sealing body,
The conductive plate includes a first plate member and a second plate member arranged in a second direction perpendicular to the first direction, connected to each other by a connecting portion, and in contact with the exposed surface,
The connecting portion is
a convex connecting portion protruding from the first plate member toward the second plate member in the second direction;
a concave connecting portion that is recessed in the second direction toward the protruding direction of the convex connecting portion and accommodates the convex connecting portion;
The power storage device, wherein the first plate-like member and the second plate-like member are in contact with each other at the connecting portion. The first plate member has a first end face facing the second plate member in the second direction,
The convex connecting portion protrudes from the first end surface toward the second plate member,
The power storage device according to claim 1, wherein the concave connecting portion contacts the first end surface. The power storage device according to claim 1 or 2, wherein a protrusion length of the convex connecting portion in the second direction is shorter than a depth of the concave connecting portion in the second direction. The second plate-like member has a second end face that faces the first plate-like member in the second direction and forms a bottom of the concave connecting portion,
The power storage device according to claim 1, wherein the convex connecting portion contacts the second end surface. The power storage device according to claim 1 , wherein a protrusion length of the convex connecting portion in the second direction is longer than a depth of the concave connecting portion in the second direction. The power storage device according to any one of claims 1 to 5, wherein at least a portion of the concave connecting portion curves toward and contacts the convex connecting portion in the first direction. The concave connecting portion has a pair of walls protruding in the second direction from each of both ends of the second plate member in the first direction,
Each of the pair of walls has a base and a tip protruding from the base in the second direction,
The power storage device according to any one of claims 1 to 6, wherein the distance between the tips in the first direction increases as you get closer to the tip of the wall in the second direction. The first plate member has the convex connecting portion,
The power storage device according to any one of claims 1 to 7, wherein the second plate-like member has the concave connecting portion. The power storage device according to any one of claims 1 to 8, wherein the current collector plate disposed at a stacked end of the electrode stack is not provided with an active material layer. The power storage device according to any one of claims 1 to 8, wherein the current collector plate having the exposed surface is the first current collector plate or the second current collector plate.

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