Electric energy storage device

Abstract

A power storage device includes a power storage module, a conductive plate laminated on the power storage module, and a sealing member therebetween. The power storage module has an electrode laminate and an enclosure. The electrode laminate has a plurality of laminated metal plates. The enclosure surrounds the side surfaces of the electrode laminate, forms an internal space between adjacent electrodes, and seals the internal space. The plurality of metal plates include a metal plate of a negative terminal electrode, a metal plate of a positive terminal electrode, and metal plates of a plurality of bipolar electrodes therebetween. The enclosure has a plurality of frame-shaped resin parts respectively provided at the edge portions of the plurality of metal plates. The metal plate at the laminated end of the electrode laminate has an exposed surface exposed from the resin part. The exposed surface has a non-contact area that does not contact the conductive plate. The sealing member has a first sealing portion that contacts the resin part and follows its inner edge. The first sealing portion is bonded to the conductive plate and the non-contact area and filled between the conductive plate and the non-contact area to seal between the conductive plate and the exposed surface.

Description

Technical Field

[0001] The present disclosure relates to an electric storage device. Background Art

[0002] As an existing electric storage module, an electric storage module including a bipolar electrode having a positive electrode formed on one surface of a metal plate and a negative electrode formed on the other surface of the metal plate is known (for example, refer to Japanese Unexamined Patent Application Publication No. 2011-204386). The electric storage module described in Japanese Unexamined Patent Application Publication No. 2011-204386 includes: an electrode laminate having a plurality of bipolar cells stacked thereon; and an enclosure that encloses an internal space formed between adjacent electrodes.

[0003] In an electric storage device including such an electric storage module, a plurality of electric storage modules are stacked with a conductive plate interposed therebetween. Adjacent electric storage modules are electrically connected to each other via the conductive plate. Summary of the Invention

[0004] In the above-described electric storage device, rust may be generated on the metal plate at the stacked end of the electric storage module. As the rust develops, the strength of the metal plate decreases, which may cause defects such as leakage of the electrolyte.

[0005] The present disclosure provides an electric storage device capable of suppressing the generation and development of rust in the metal plate at the stacked end.

[0006] The electric storage device of the present disclosure includes an electric storage module, a conductive plate stacked on the electric storage module, and a sealing member provided between the conductive plate and the electric storage module. The electric storage module includes an electrode laminate and an enclosure. The electrode laminate includes a plurality of metal plates stacked thereon. The enclosure is provided so as to surround the side surfaces of the electrode laminate. The enclosure forms an internal space between adjacent electrodes and encloses the internal space. The plurality of metal plates include a metal plate of a negative terminal electrode, a metal plate of a positive terminal electrode, and metal plates of a plurality of bipolar electrodes provided between the negative terminal electrode and the positive terminal electrode. The enclosure has a plurality of frame-shaped resin portions provided at the edge portions of the plurality of metal plates included in the electrode laminate. The metal plate at the stacked end of the electrode laminate has an exposed surface exposed from the resin portion. The exposed surface has a contact area that contacts the conductive plate and a non-contact area that does not contact the conductive plate. The sealing member has a first sealing portion. The first sealing portion is provided along the inner edge of the resin portion in contact with the resin portion. The first sealing portion is bonded to the conductive plate and the non-contact area and fills the space between the conductive plate and the non-contact area. The first sealing portion seals the space between the conductive plate and the exposed surface.

[0007] In this power storage device, the metal plate at the stacked end has an exposed surface that protrudes from the resin part. The exposed surface has a contact area that contacts the conductive plate and a non-contact area that does not contact the conductive plate. The first sealing part is provided along the inner edge of the resin part in contact with the resin part, bonded to the conductive plate and the non-contact area, filled between the conductive plate and the non-contact area, and seals between the conductive plate and the exposed surface. Therefore, the generation and development of rust in the metal plate at the stacked end can be suppressed.

[0008] Alternatively, the conductive plate may have a plurality of plate-like members connected to each other, and the sealing member may have a second sealing part. The second sealing part is provided along the connecting part formed between adjacent plate-like members. The second sealing part is bonded to each of the adjacent plate-like members and the non-contact area, and filled between each of the adjacent plate-like members and the non-contact area. The second sealing part seals between the conductive plate and the exposed surface. In this case, the second sealing part fills the gap between the plate-like members constituting the conductive plate. Thereby, the intrusion of moisture from this gap can be suppressed, and thus the generation and development of rust in the metal plate at the stacked end can be suppressed.

[0009] Alternatively, the conductive plate may have one surface and another surface in the stacking direction of the electrode stack. Alternatively, the second sealing part may be filled between adjacent plate-like members and continuously provided from one surface to the other surface. In this case, the generation and development of rust in the metal plate at the stacked end can be further suppressed.

[0010] Alternatively, at the end of the connecting part in the stacking direction of the electrode stack, the interval between adjacent plate-like members becomes larger as it approaches the metal plate at the stacked end. In this case, it is easy to fill the sealing member into the gap between the plate-like members constituting the conductive plate.

[0011] Alternatively, the sealing member may be a liquid gasket. In this case, the sealing member is easily filled between the conductive plate and the non-contact area.

[0012] Alternatively, when viewed from the stacking direction of the electrode stack, the resin part may overlap with the outer edge of the conductive plate. In this case, damage to the metal plate at the stacked end due to contact with the outer edge of the conductive plate can be suppressed.

[0013] Alternatively, the above power storage device may further include a detection element connected to the end surface of the conductive plate. Alternatively, the first sealing part extends from the inner edge to a position corresponding to the connecting part formed between the detection element and the conductive plate in the metal plate at the stacked end. In this case, for example, the situation where the metal plate at the stacked end enters the gap between the detection element and the conductive plate due to the internal pressure change of the power storage module is suppressed. Description of the Drawings

[0014] Figure 1 It is a schematic cross-sectional view showing an example of an electric storage device.

[0015] Figure 2 It is a cross-sectional view showing the internal structure of the electric storage module.

[0016] Figure 3 It is a top view showing the electric storage module and the conductive plate on the electric storage module.

[0017] Figure 4 It is a perspective view of the plate-like member of the conductive plate.

[0018] Figure 5 It is a perspective view of the plate-like member of the conductive plate.

[0019] Figure 6 It is a perspective view of the detection element.

[0020] Figure 7 It is a top view for explaining the position where the sealing member is provided.

[0021] Figure 8A and Figure 8B It is a cross-sectional view for explaining a method of closing between the plate-like members by the second sealing portion.

[0022] Figure 9A and Figure 9B It is a cross-sectional view for explaining a method of closing between the plate-like members by the second sealing portion.

[0023] Figure 10 It is a cross-sectional view for explaining a method of closing between the electric storage module and the conductive plate by the first sealing portion.

[0024] Figure 11A and Figure 11B It is a cross-sectional view for explaining another method of closing between the plate-like members by the second sealing portion. Detailed Description of the Invention

[0025] Hereinafter, embodiments 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 duplicate descriptions are omitted.

[0026] Figure 1 It is a schematic cross-sectional view showing an example of the electric storage device of the present embodiment. Figure 1The power storage device 1 shown is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 includes: a module stack 2 including a plurality of stacked power storage modules 4; and a restraining member 3 for applying a restraining 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 stack 2 is referred to as the Z direction, the first direction orthogonal to the stacking direction is referred to as the X direction, and the second direction orthogonal to the stacking direction and the first direction is referred to as the Y direction.

[0027] The module stack 2 includes a power storage module 4, a conductive plate 5 stacked on the power storage module 4, and a detection element 70 (see Figure 3 ), and the sealing member 80 (refer to Figure 7 ). The detection element 70 and the sealing member 80 will be described later. In the present embodiment, the module stack 2 includes a plurality of power storage modules 4 and a plurality of conductive plates 5. The number of the power storage modules 4 is, for example, 5, and the number of the conductive plates 5 is, for example, 4. 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-hydrogen secondary battery, a lithium-ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-hydrogen secondary battery is exemplified as the power storage module 4.

[0028] The plurality of power storage modules 4 are stacked in the Z direction with the conductive plate 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 of the conductive plate 5 include aluminum. A plating layer such as nickel may be formed on the surface of the conductive plate 5. Figure 1 In the example shown, the area of the conductive plate 5 when viewed from the Z direction is smaller than the area of the power storage module 4. However, from the viewpoint of improving heat dissipation, the area of the conductive plate 5 may be the same as or larger than the area of the power storage module 4.

[0029] The plurality of conductive plates 5 include a plurality of (two in the present embodiment) conductive plates 5A disposed between the storage modules 4 adjacent in the Z direction, and a plurality of (two in the present embodiment) conductive plates 5B located at the stacking end of the module stack 2. The storage modules 4 adjacent to each other are electrically connected via the conductive plates 5A. An insulating plate B is disposed outside the conductive plates 5B. One conductive plate 5B is connected to the negative terminal 7, and the other conductive plate 5B is connected to the positive terminal 6. The positive terminal 6 and the negative terminal 7 are each drawn out from the edge of the conductive plate 5B in the X direction, for example. The storage device 1 is charged and discharged through the positive terminal 6 and the negative terminal 7.

[0030] A cooling fluid F such as air is provided inside the conductive plate 5A disposed between the power storage modules 4 (see Figure 3 and Figure 4)A plurality of through-holes (flow paths) 5a for circulation. 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 for electrically connecting the power storage modules 4 adjacent to each other, and has a function as a heat dissipation plate for dissipating heat from the power storage module 4 by allowing the cooling fluid F to flow through the plurality of through-holes 5a.

[0031] The restraining member 3 includes: a pair of end plates 8 sandwiching the module laminate 2 in the Z direction; and a fastening bolt 9 and a nut 10 for fastening the end plates 8 to each other. The end plate 8 is a rectangular metal plate having an area that is one size larger than the areas of the power storage module 4, the conductive plate 5, and the conductive plate 5B when viewed from the Z direction. An insulating plate B having electrical insulation properties is provided between the end plate 8 and the conductive plate 5B. Through this insulating plate B, the end plate 8 and the conductive plate 5B are insulated from each other.

[0032] At the edge portion of the end plate 8, insertion through-holes 8a are provided at positions outside the module laminate 2. The fastening bolt 9 passes through the insertion through-hole 8a of one end plate 8 and out through the insertion through-hole 8a of the other end plate 8. A nut 10 is screwed onto the tip portion of the fastening bolt 9 protruding from the insertion through-hole 8a of the other end plate 8. Thus, the power storage module 4, the conductive plate 5, and the conductive plate 5B are clamped by the end plates 8 and unitized into the module laminate 2. In addition, a restraining load is applied to the module laminate 2 in the Z direction.

[0033] Next, the configuration of the power storage module 4 will be described in detail. Figure 2 It is a cross-sectional view showing the internal configuration of the power storage module. As Figure 2 shown, the power storage module 4 includes an electrode laminate 11 and a resin enclosure 12 that encloses the electrode laminate 11. The power storage module 4 is formed, for example, in a rectangular parallelepiped shape.

[0034] The electrode laminate 11 includes: a plurality of electrodes laminated along the lamination direction (Z direction) with a separator 13 interposed therebetween; and metal plates 20A and 20B disposed at the lamination ends of the electrode laminate 11. The plurality of electrodes include a laminate of a plurality of bipolar electrodes 14, a negative terminal electrode 18, and a positive terminal electrode 19. The laminate of the plurality of bipolar electrodes 14 is provided between the negative terminal electrode 18 and the positive terminal electrode 19.

[0035] The bipolar electrode 14 has: a metal plate 15 including one surface 15a and another surface 15b on the side opposite to the one surface 15a; a positive electrode 16 provided on the one surface 15a; and a negative electrode 17 provided on the another surface 15b. The positive electrode 16 is a positive electrode active material layer formed by coating a positive electrode active material onto the metal plate 15. The negative electrode 17 is a negative electrode active material layer formed by coating a negative electrode active material onto the metal plate 15. In the electrode laminate 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of another bipolar electrode 14 adjacent to one side in the Z direction with the separator 13 therebetween. In the electrode laminate 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 therebetween.

[0036] The negative terminal electrode 18 has the metal plate 15 and the negative electrode 17 provided on the another surface 15b of the metal plate 15. The negative terminal electrode 18 is disposed on one end side in the Z direction such that the another surface 15b faces the central side in the Z direction of the electrode laminate 11. A metal plate 20A is further laminated on the one surface 15a of the metal plate 15 of the negative terminal electrode 18, and is electrically connected to one conductive plate 5 adjacent to the power storage module 4 via the metal plate 20A (see Figure 1 ). The negative electrode 17 provided on the another surface 15b of the metal 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 therebetween.

[0037] The positive terminal electrode 19 has the metal plate 15 and the positive electrode 16 provided on the one surface 15a of the metal plate 15. The positive terminal electrode 19 is disposed on the other end side in the Z direction such that the one surface 15a faces the central side in the Z direction of the electrode laminate 11. A metal plate 20B is further laminated on the another surface 15b of the metal plate 15 of the positive terminal electrode 19, and is electrically connected to the other conductive plate 5 adjacent to the power storage module 4 via the metal plate 20B (see Figure 1 ). The positive electrode 16 provided on the one surface 15a of the metal 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 therebetween.

[0038] The metal plate 15 includes a metal such as nickel or nickel-plated steel sheet. As an example, the metal plate 15 is a rectangular metal foil including nickel. Each metal plate 15 is one of the metal plates included in the electrode laminate 11. The edge portion 15c of the metal plate 15 is in a rectangular frame shape and is an uncoated area where neither the positive electrode active material nor the negative electrode active material is coated. As the positive electrode active material constituting the positive electrode 16, nickel hydroxide can be cited, for example. As the negative electrode active material constituting the negative electrode 17, a hydrogen storage alloy can be cited, for example. In the present embodiment, the formation area of the negative electrode 17 in the other surface 15b of the metal plate 15 is one size larger than the formation area of the positive electrode 16 in one surface 15a of the metal plate 15. The electrode laminate 11 has a plurality of stacked metal plates 15, 20A, 20B.

[0039] The separator 13 is a member for preventing short circuits between the metal plates 15 and is formed in a sheet shape, for example. As the separator 13, a porous membrane including a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a woven fabric or a non-woven fabric including polypropylene, methyl cellulose, etc. can be exemplified. The separator 13 can also be a separator strengthened with a vinylidene fluoride resin compound. In addition, the separator 13 is not limited to a sheet shape, and a bag-shaped separator can also be used.

[0040] The metal plates 20A and 20B are members substantially the same as the metal plate 15 and include a metal such as nickel or nickel-plated steel sheet. The metal plates 20A and 20B are each one of the metal plates included in the electrode laminate 11. As an example, the metal plates 20A and 20B are rectangular metal foils including nickel. The metal plates 20A and 20B are uncoated electrodes on which neither the positive electrode active material layer nor the negative electrode active material layer is coated on one surface 20a and the other surface 20b.

[0041] The metal plate 20A is located at one lamination end of the electrode laminate 11. Due to the metal plate 20A, the negative terminal electrode 18 is disposed between the metal plate 20A and the bipolar electrode 14 along the Z direction. The metal plate 20B is located at the other lamination end of the electrode laminate 11. Due to the metal plate 20B, the positive terminal electrode 19 is disposed between the metal plate 20B and the bipolar electrode 14 along the Z direction. In the electrode laminate 11, the central region of the electrode laminate 11 (the region where the active material layer is disposed in the bipolar electrode 14, the negative terminal electrode 18, and the positive terminal electrode 19) bulges more in the Z direction than the surrounding region. Therefore, the metal plates 20A and 20B bend in the direction in which the central regions of the metal plates 20A and 20B move away from each other. The central regions of one surface 20a of the metal plate 20A and the other surface 20b of the metal plate 20B are in contact with the conductive plate 5.

[0042] The closed body 12 is formed in a rectangular cylindrical shape as a whole by, for example, an insulating resin. The closed body 12 is provided so as to surround the side surface 11a of the electrode laminate 11. The closed body 12 holds the edge portion 15c at the side surface 11a. The closed body 12 has: a plurality of first closed portions 21 (resin portions) in a frame shape, which are respectively provided at the edge portions of the metal plates included in the electrode laminate 11 (that is, the edge portion 15c of the metal plate 15 and the edge portions 20c of the metal plates 20A and 20B); and a second closed portion 22, which surrounds the first closed portions 21 from the outside along the side surface 11a and is joined to each of the first closed portions 21. The first closed portion 21 and the second closed portion 22 are, for example, insulating resins having alkali resistance. Examples of the constituent materials of the first closed portion 21 and the second closed portion 22 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like.

[0043] The first closed portion 21 is continuously provided over the entire circumference of the edge portion 15c of the metal plate 15 or the edge portions 20c of the metal plates 20A and 20B, and has a rectangular frame shape when viewed from the Z direction. The first closed portion 21 is, for example, welded to the edge portion 15c of the metal plate 15 or the edge portions 20c of the metal plates 20A and 20B by ultrasonic waves or heat and is hermetically joined. The first closed portion 21 includes: an outer portion 21a, which extends more outward than the edge of the metal plate 15 or the metal plates 20A and 20B; and an inner portion 21b, which is located on the inner side of the edge of the metal plate 15 or the metal plates 20A and 20B. The tip portions (outer edge portions) of the outer portion 21a of the first closed portion 21 are joined to the second closed portion 22 through a welding layer 23. The welding layer 23 is formed, for example, by the tip portions of the first closed portion 21 melted by hot plate welding being joined to each other. The outer portions 21a of the first closed portions 21 adjacent to each other in the Z direction may be separated from each other or may be in contact with each other. In addition, the outer portions 21a of the first closed portions 21 adjacent to each other in the Z direction may also be joined to each other by, for example, hot plate welding.

[0044] The plurality of first closed portions 21 include: a plurality of first closed portions 21A, which are provided at the bipolar electrode 14 and the positive terminal electrode 19; a first closed portion 21B, which is provided at the negative terminal electrode 18; a first closed portion 21C, which is provided at the metal plate 20A; and first closed portions 21D and 21E, which are provided at the metal plate 20B.

[0045] The first sealing part 21A is joined to one surface 15a of the metal plate 15 of the bipolar electrode 14 and the positive terminal electrode 19. The inner part 21b of the first sealing part 21A is located between the edge parts 15c of the metal plate 15 adjacent to each other in the Z direction. The region where the edge part 15c on one surface 15a of the metal plate 15 overlaps with the first sealing part 21A becomes the joining region between the metal plate 15 and the first sealing part 21A.

[0046] In the present embodiment, the first sealing part 21A is formed in a double-layer structure by folding one film into two. The outer edge part of the first sealing part 21A embedded in the second sealing part 22 is a folded-back part (bent part) of the film. The first layer film constituting the first sealing part 21A is joined to one surface 15a. The inner edge of the second layer film is located at a position outside the inner edge of the first layer film, and a stepped part for placing the separator 13 is formed. The inner edge of the second layer film is located at a position inside the edge of the metal plate 15.

[0047] The first sealing part 21B is joined to one surface 15a of the metal plate 15 of the negative terminal electrode 18. The inner part 21b of the first sealing part 21B is located between the edge part 15c of the metal plate 15 of the negative terminal electrode 18 and the edge part 20c of the metal plate 20A adjacent to each other in the Z direction. The region where the edge part 15c on one surface 15a of the metal plate 15 overlaps with the inner part 21b of the first sealing part 21B becomes the joining region between the metal plate 15 and the first sealing part 21B. The first sealing part 21B is also joined to the other surface 20b of the metal plate 20A. The region where the edge part 20c on the other surface 20b of the metal plate 20A overlaps with the first sealing part 21B becomes the joining region between the metal plate 20A and the first sealing part 21B. In the present embodiment, the first sealing part 21B is also joined to the edge part 20c on the other surface 20b of the metal plate 20A.

[0048] The first sealing part 21C is joined to one surface 20a of the metal plate 20A. In the present embodiment, the first sealing part 21C is located at the position on the most end side in the Z direction among the plurality of first sealing parts 21. The region where the edge part 20c on one surface 20a of the metal plate 20A overlaps with the first sealing part 21C becomes the joining region between the metal plate 20A and the first sealing part 21C.

[0049] In the present embodiment, the outer edge portions of the first closing portions 21B and 21C embedded in the second closing portion 22 are continuous with each other. That is, the first closing portions 21B and 21C are formed by folding a single film with the edge portion 20c of the metal plate 20A sandwiched therebetween into two. The outer edge portions of the first closing portions 21B and 21C are the folded-back portions (bent portions) of the film. The film constituting the first closing portions 21B and 21C is joined to the edge portion 20c on both of the one surface 20a and the other surface 20b of the metal plate 20A. In this way, by joining the two surfaces of the metal plate 20A to the first closing portions 21B and 21C, it is possible to suppress the leakage of the electrolytic solution caused by the so-called alkali creep phenomenon.

[0050] The first closing portion 21D is joined to the one surface 20a of the metal plate 20B. The inner portion 21b of the first closing portion 21D is located between the edge portion 15c of the metal plate 15 of the positive terminal electrode 19 adjacent to each other in the Z direction and the edge portion 20c of the metal plate 20B. The region where the edge portion 20c on the one surface 20a of the metal plate 20B overlaps with the first closing portion 21D becomes the joining region between the metal plate 20B and the first closing portion 21D.

[0051] The first closing portion 21E is disposed at the edge portion 20c on the other surface 20b of the metal plate 20B. In the present embodiment, the first closing portion 21E is located at the position on the most other end side in the Z direction among the plurality of first closing portions 21. Further, in the present embodiment, the first closing portion 21E is not joined to the metal plate 20B.

[0052] The metal plate 20A located at the lamination end has an exposed surface 20d exposed from the first closing portion 21. The one surface 20a of the metal plate 20A has an exposed surface 20d exposed from the first closing portion 21C. The other surface 20b of the metal plate 20B has an exposed surface 20d exposed from the first closing portion 21E. The exposed surface 20d has a contact region 20e (for example, refer to Figure 10 ) that contacts (abuts against) and is electrically connected to the conductive plate 5, and a non-contact region 20f (for example, refer to Figure 10 ) that does not contact (does not abut against) the conductive plate 5.

[0053] In the present embodiment, the outer edge portions of the first closing portions 21D and 21E embedded in the second closing portion 22 are continuous with each other. That is, the first closing portions 21D and 21E are formed by folding a single film with the edge portion 20c of the metal plate 20B sandwiched therebetween into two. The outer edge portions of the first closing portions 21D and 21E are the folded-back portions (bent portions) of the film. The film constituting the first closing portions 21D and 21E is joined to the edge portion 20c on both of the one surface 20a and the other surface 20b of the metal plate 20B.

[0054] In the bonding region, the surfaces of the metal plates 15, 20A, and 20B are roughened. The roughened region may be only the bonding region, but in the present embodiment, the entire surface 15a of the metal plate 15 is roughened. In addition, the entire surfaces 20a and 20b of the metal plate 20A are roughened. Further, the entire surface 20a of the metal plate 20B is roughened.

[0055] The roughening can be achieved, for example, by forming a plurality of protrusions using electrolytic plating. By forming a plurality of protrusions in the bonding region, molten resin enters between the plurality of protrusions formed by the roughening at the bonding interface with the first sealing portion 21 in the bonding region, and an anchoring effect is exerted. Thereby, the bonding strength between the metal plates 15, 20A, 20B and the first sealing portion 21 can be improved. The protrusions formed during roughening have, for example, a shape that becomes thicker from the base end side to the tip end side. Thereby, the cross-sectional shape between adjacent protrusions becomes an undercut shape, and the anchoring effect can be improved.

[0056] The second sealing portion 22 is provided outside the electrode laminate 11 and the first sealing portion 21 so as to surround the side surface 11a of the electrode laminate 11, and constitutes the outer wall (box body) of the power storage module 4. The second sealing portion 22 is formed, for example, by injection molding of resin, and extends along the entire length of the electrode laminate 11 in the Z direction. The second sealing portion 22 has a rectangular frame shape extending in the Z direction as an axis. The second sealing portion 22 is welded, for example, to the outer surface of the first sealing portion 21 by heat during injection molding.

[0057] The sealing body 12 forms an internal space V between adjacent electrodes and seals the internal space V. More specifically, the second sealing portion 22 and the first sealing portion 21 together seal between the bipolar electrodes 14 adjacent to each other in the Z direction, between the negative terminal electrode 18 and the bipolar electrode 14 adjacent to each other in the Z direction, and between the positive terminal electrode 19 and the bipolar electrode 14 adjacent to each other in the Z direction, respectively. Thereby, hermetically separated internal spaces V are respectively 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. In the internal space V, for example, an electrolytic solution (not shown) containing an alkaline solution such as an aqueous potassium hydroxide solution is accommodated. 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 metal plate 20A and the negative terminal electrode 18, and between the metal plate 20B and the positive terminal electrode 19, respectively.

[0058] Next, the detailed configuration of the aforementioned conductive plate 5 will be described. Figure 3 is a plan view showing the power storage module 4 and the conductive plate 5A on the power storage module 4. As Figure 3As shown, when viewed from the Z direction (i.e., in a top view), the conductive plate 5A has a rectangular shape with an area that is one size smaller than the planar shape of the power storage module 4. The conductive plate 5A is located within the frame of the second closed portion 22. In the present 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. The pair of long sides 5b and 5c extend along the X direction and face each other in the Y direction. The pair of short sides 5d and 5e extend along the Y direction and face each other in the X direction.

[0059] In the present embodiment, the pair of long sides 5b and 5c and the pair of short sides 5d and 5e form the outer edge of the conductive plate 5A. When viewed from the Z direction, the pair of long sides 5b and 5c overlap with the first closed portion 21. When viewed from the Z direction, the pair of short sides 5d and 5e do not overlap with the first closed portion 21. The first closed portion 21 disposed on the side of the pair of short sides 5d and 5e is provided at a position closer to the inside than the first closed portion 21 disposed on the side of the pair of long sides 5b and 5c. The length of the first closed portion 21 in the X direction disposed on the side of the pair of short sides 5d and 5e is longer than the length of the first closed portion 21 in the Y direction disposed on the side of the pair of long sides 5b and 5c.

[0060] The conductive plate 5A further includes one surface 5f and another surface 5g in the thickness direction (Z direction) (see Figure 8A ). One surface 5f abuts against the metal plate 20B at the stacked end of the power storage module 4 adjacent to one side in the Z direction. Another surface 5g abuts against the metal plate 20A at the stacked end of the power storage module 4 adjacent to the other side in the Z direction. As described above, in the electrode laminate 11, the central region of the electrode laminate 11 bulges more in the Z direction than the surrounding region. Therefore, the central regions of one surface 5f and another surface 5g abut against the central regions of one surface 20a of the metal plate 20A and another surface 20b of the metal plate 20B. The conductive plate 5A is arranged to abut against the metal plates 20A and 20B at the stacked ends of the adjacent power storage modules 4, and electrically connects the plurality of power storage modules 4 in series.

[0061] Detection elements 70 are respectively connected to the end faces on the short side 5d side and the short side 5e side of the conductive plate 5A. The detection element 70 is, for example, a sensor that includes elements for detecting the temperature of the power storage module 4 and elements for detecting the voltage output from the power storage module 4 and monitors the state of the power storage module 4. The detection element 70 is, for example, formed of an insulating resin having alkali resistance such as polypropylene (PP) with the same thickness as the conductive plate 5A.

[0062] The conductive plate 5A has a plurality of (four in this embodiment) plate-like members 50 arranged along the X direction and connected to each other. Each plate-like member 50 has a rectangular shape when viewed from the Z direction (i.e., in plan view). In this embodiment, each plate-like 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-like members 50 are arranged along the X direction such that the long sides of adjacent plate-like members 50 face each other in the X direction.

[0063] The plate-like member 50 includes one face 50a and another face 50b in the thickness direction (Z direction). One face 50a forms a part of one face 5f. The other face 50b forms a part of the other face 5g.

[0064] The plate-like member 50 further includes: a pair of end faces 50c and 50d that face each other in the X direction; and a pair of end faces 50e and 50f that face each other in the Y direction. Each of the end faces 50c and 50d is a flat face including the long side of the plate-like member 50 and is along the YZ plane. Each of the end faces 50c and 50d extends along the Y direction. The end face 50c is located on the short side 5d side in the X direction, and the end face 50d is located on the short side 5e side in the X direction. The end face 50c of one of the two adjacent plate-like members 50 in the X direction faces the end face 50d of the other plate-like member 50 in the X direction.

[0065] Each of the end faces 50e and 50f is a flat face including the short side of the plate-like member 50 and is along the XZ plane. Each of the end faces 50e and 50f extends along the X direction. The end face 50e is located on the long side 5b side and connects the one ends of the end faces 50c and 50d in the Y direction to each other. The end face 50f is located on the long side 5c side and connects the other ends of the end faces 50c and 50d in the Y direction to each other. In each plate-like member 50, the positions of the end faces 50e in the Y direction are the same as each other, and the positions of the end faces 50f in the Y direction are the same as each other.

[0066] 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 side than the plurality of plate-like members 50A. The end face 50c of the plate-like member 50B arranged closest to the short side 5d side forms the end face on the short side 5d side of the conductive plate 5A. The end face 50d of the plate-like member 50A arranged closest to the short side 5e side forms the end face on the short side 5e side of the conductive plate 5A.

[0067] Figure 4 It is a perspective view of the plate-like member 50A of the conductive plate 5A. Figure 5 It is a perspective view of the plate-like member 50B of the conductive plate 5A. As Figure 4and Figure 5 As shown in Figure 5 , a plurality of the aforementioned through-holes 5a are formed in the plate-like members 50A and 50B. Each through-hole 5a penetrates from the end face 50e of the plate-like members 50A and 50B to the end face 50f inside the plate-like member 50 along the Y direction, and is arranged along the X direction. The cross-sectional shape of each through-hole 5a is, for example, a rectangular shape with the X direction as the long side direction when viewed from the Y direction. The cooling fluid F flows in each through-hole 5a. The cooling fluid F flows in each through-hole 5a along the Y direction from the end face 50e side to the end face 50f side of the plate-like members 50A and 50B, for example.

[0068] As Figure 4 shown in Figure 4 , the plate-like member 50A has a convex portion 61 provided on the end face 50d and a concave portion 62 provided on the end face 50c. The convex portion 61 and the concave portion 62 are formed in a shape that fits together. The convex portion 61 extends from one end in the Y direction to the other end of the end face 50d of the plate-like member 50A, and has the same XZ cross-sectional shape from one end to the other end in the Y direction of the end face 50d. That is, the XZ cross-sectional shape of the convex portion 61 is the same in the Y direction. The convex portion 61 extends linearly along the X direction from the central portion in the Z direction on the end face 50d of the plate-like member 50A.

[0069] The concave portion 62 extends from one end in the Y direction to the other end of the end face 50c, and has the same XZ cross-sectional shape from one end to the other end in the Y direction of the end face 50c. That is, the XZ cross-sectional shape of the concave portion 62 is the same in the Y direction. The concave portion 62 has a pair of wall portions 62a that extend linearly along the X direction from both end portions in the Z direction of the end face 50c, respectively. Two adjacent plate-like members 50A in the X direction are connected to each other by fitting the convex portion 61 of one plate-like member 50A and the concave portion 62 of the other plate-like member 50A to form a connecting portion 60 (see Figure 8B ).

[0070] As Figure 5 shown in Figure 5 , the plate-like member 50B has a convex portion 61 instead of the concave portion 62 on the end face 50c (see Figure 4 ), which is different from the plate-like member 50A (see Figure 4 ), and is otherwise the same as the plate-like member 50A. The plate-like member 50A and the plate-like member 50B adjacent to each other in the X direction are connected to each other by fitting the concave portion 62 of the plate-like member 50A and the convex portion 61 of the plate-like member 50B to form a connecting portion 60.

[0071] Since the plate-like members 50A and 50B are connected, a plurality of (three in this embodiment) gaps G are formed on each of one surface 5f and the other surface 5g of the conductive plate 5A. The gaps G are formed between two adjacent plate-like members 50A and between the adjacent plate-like members 50A and 50B. The gap G extends in the Y direction along the end face 50d and connects between the short side 5d and the short side 5e.

[0072] Figure 6 is a perspective view of the detection element. In Figure 6 is shown a detection element 70 connected to the short side 5d side of the conductive plate 5A, but the detection element 70 connected to the short side 5e side of the conductive plate 5A has the same configuration. As Figure 6 shown, the detection element 70 has a rectangular shape when viewed from the Z direction (i.e., when viewed from above), for example. 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 surface 70a forms the same plane as one surface 5f, for example. The other surface 70b forms the same plane as the other surface 5g, for example.

[0073] The detection element 70 further includes: a pair of end faces 70c and 70d that face each other in the X direction; and a pair of end faces 70e and 70f that face each other in the Y direction. Each of the end faces 70c and 70d is a flat surface including the long side of the detection element 70 and is along the YZ plane. Each of the end faces 70c and 70d extends in the Y direction. The end face 70c is located on the side of the conductive plate 5, and the end face 70d is located on the opposite side of the conductive plate 5.

[0074] Each of the end faces 70e and 70f is a flat surface including the short side of the detection element 70 and is along the XZ plane. Each of the end faces 70e and 70f extends in the X direction. The end face 70e is located on the side of the long side 5b, and the end face 70f is located on the side of the long side 5c. The end face 70e forms the same plane as each end face 50e, for example. The end face 70f forms the same plane as each end face 50f, for example.

[0075] The detection element 70 has a recess 62 at the end face 70c. The detection element 70 on the short side 5d side of the conductive plate 5A and the plate-like member 50B adjacent in the X direction are connected by engaging the recess 62 of the detection element 70 and the protrusion 61 of the plate-like member 50B to form a connecting portion 60. The detection element 70 on the short side 5e side of the conductive plate 5A and the plate-like member 50A adjacent in the X direction are connected by engaging the recess 62 of the detection element 70 and the protrusion 61 of the plate-like member 50A to form a connecting portion 60.

[0076] Although the illustration is omitted, the conductive plate 5B includes a plate-like member. When viewed from the Z direction, the conductive plate 5B has, for example, a rectangular shape with the same area as the planar shape of the connecting body formed by connecting the conductive plate 5A and the pair of detection elements 70, and is disposed within the frame of the second closing portion 22.

[0077] Next, the above-described sealing member 80 (see Figure 7 ) will be described. The sealing member 80 includes, for example, resin. The sealing member 80 includes, for example, a material that does not contain low molecular weight siloxane. In this case, contact failure of the relay is suppressed. The sealing member 80 includes, for example, a material that is not easily hydrolyzed. In this case, a decrease in adhesive strength due to moisture is suppressed. As an example, the sealing member 80 includes modified silicone. The sealing member 80 is, for example, a liquid gasket. In the present embodiment, although the sealing member 80 is an insulating resin, it may also be a conductive resin. The sealing member 80 is disposed between the conductive plate 5 and the power storage module 4. The sealing member 80 is disposed between the metal plates 20A and 20B at the laminated ends of the conductive plate 5 and the power storage module 4, and joins (adheres) them to each other. Figure 1 The module laminate 2 shown is formed, for example, by laminating the conductive plate 5 and the power storage module 4 in order from below. The sealing member 80 is disposed between the conductive plate 5 and the power storage module 4 in a liquid state before curing when the conductive plate 5 and the power storage module 4 are laminated. Thereby, the sealing member 80 can follow the undulations or irregularities of the surface. The sealing member 80 is applied, for example, by a dispenser.

[0078] Specifically, first, the sealing member 80 is disposed at a predetermined position on the conductive plate 5B disposed at the lamination position, and then the power storage module 4 is laminated on the conductive plate 5B, and the conductive plate 5B and the power storage module 4 are joined by the sealing member 80. Next, the sealing member 80 is disposed at a predetermined position on the power storage module 4, and then the conductive plate 5A is laminated on the power storage module 4, and the power storage module 4 and the conductive plate 5A are joined by the sealing member 80. Similarly, the process of disposing the sealing member 80 at a predetermined position and laminating the power storage module 4 and the conductive plate 5A in order is repeated. Finally, the sealing member 80 is disposed at a predetermined position on the uppermost power storage module 4, and then 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 sealing member 80. After all the conductive plates 5 and the power storage modules 4 are laminated, the sealing member 80 is cured, thereby forming the module laminate 2. When the conductive plate 5 and the power storage module 4 are laminated, since the sealing member 80 is in a liquid state, it is difficult to apply surface pressure to the conductive plate 5 and the power storage module 4. Therefore, as the sealing member 80, a liquid sealant with a long curing time and that does not cure during the lamination process is selected.

[0079] Figure 7 is a top view for explaining the position where the sealing member 80 is disposed. InFigure 7 Shown is a sealing member 80 provided on the power storage module 4 other than the uppermost stage in the method for forming the module laminate 2 described above (corresponding to the sealing member 80 provided between the conductive plate 5A and the metal plate 20A of the power storage module 4 in the module laminate 2). The sealing member 80 has, in the exposed surface 20d of one surface 20a of the metal plate 20A: a first sealing portion 80a that is provided in a ring shape along the inner edge 21c of the first closing portion 21 in contact with the first closing portion 21 provided at the edge portion 20c of the metal plate 20A; and a plurality (three in this embodiment) of second sealing portions 80b that are provided along the connecting portion 60 formed between adjacent plate-like members 50 (see Figure 3 ).

[0080] The first sealing portion 80a has, for example, a rectangular ring shape and is continuously provided over the entire circumference of the first closing portion 21. The first sealing portion 80a hermetically seals the power storage module 4 and the conductive plate 5. The second sealing portion 80b extends along the Y direction. Both end portions of the second sealing portion 80b are connected to the first sealing portion 80a. The second sealing portion 80b hermetically seals between adjacent plate-like members 50.

[0081] Although not shown, in the method for forming the module laminate 2 described above, the sealing member 80 provided on the conductive plate 5A (corresponding to the sealing member 80 provided between the conductive plate 5A and the metal plate 20B of the power storage module 4 in the module laminate 2) is provided in the same manner as the sealing member 80 provided on the power storage module 4 other than the uppermost stage. Further, since the conductive plate 5B includes one plate-like member, the sealing member 80 provided on the power storage module 4 at the uppermost stage (corresponding to the sealing member 80 provided between the conductive plate 5B and the metal plate 20A of the power storage module 4 in the module laminate 2) and the sealing member 80 provided on the conductive plate 5B (corresponding to the sealing member 80 provided between the conductive plate 5B and the metal plate 20B of the power storage module 4 in the module laminate 2) do not include the second sealing portion 80b.

[0082] See Figure 8A , Figure 8B , Figure 9A and Figure 9B to describe the method of closing between the plate-like members 50A by the second sealing portion 80b. In Figure 8AIn [the figure], a state is shown in which a second sealing portion 80b is provided on the power storage module 4. The second sealing portion 80b is provided corresponding to a gap G formed between plate-like members 50A adjacent to each other at an end portion in the Z direction of the connecting portion 60. The gap G is formed at both end portions in the Z direction of the connecting portion 60. The second sealing portion 80b is provided corresponding to the gap G on the side of the metal plate 20A (the other surface 5g side). The second sealing portion 80b is provided so as to overlap the gap G on the side of the metal plate 20A when viewed from the Z direction. In the present embodiment, the gap G is formed between an end portion in the Z direction of the end face 50d and a top end portion of the wall portion 62a. The end portion in the Z direction of the end face 50d and the top end portion of the wall portion 62a each have a chamfered shape (R shape or a shape with rounded corners). Therefore, at the end portion in the Z direction of the connecting portion 60, the interval between the plate-like members 50A adjacent to each other becomes larger as it approaches the metal plates 20A and 20B.

[0083] In Figure 8B [the figure], a state is shown in which the conductive plate 5A is laminated on the power storage module 4. As Figure 8B shown, since the conductive plate 5A is laminated on the metal plate 20A, the second sealing portion 80b enters between the plate-like members 50A in the connecting portion 60 and closes the space between the plate-like members 50A. The sealing member 80 is guided into the gap G on the side of the metal plate 20A along the chamfered shape of the end portion in the Z direction of the end face 50d and the top end portion of the wall portion 62a. The gap G on the side of the metal plate 20A is blocked by the second sealing portion 80b. In addition, since the second sealing portion 80b enters the gap G, a situation in which the second sealing portion 80b wets and spreads more than necessary on the metal plate 20A and causes a decrease in conductivity is suppressed. In the exposed surface 20d of one surface 20a of the metal plate 20A, a portion corresponding to the gap G on the side of the metal plate 20A becomes a non-contact region 20f.

[0084] In Figure 9A [the figure], a state is shown in which the sealing member 80 is provided on the conductive plate 5A. As Figure 9A shown, the second sealing portion 80b is provided corresponding to the gap G on the side of the metal plate 20B. At this time, at the end portion in the Z direction of the connecting portion 60, the interval between the plate-like members 50A adjacent to each other becomes larger as it approaches the metal plates 20A and 20B, so that the position of the gap G can be easily determined. Therefore, the second sealing portion 80b can be easily provided.

[0085] In Figure 9B [the figure], a cross-sectional view is shown which represents a state in which the power storage module 4 is laminated on the conductive plate 5A. As Figure 9BAs shown, since the secondary battery module 4 is stacked on the conductive plate 5A, the second sealing portion 80b enters between the plate-like members 50A in the connecting portion 60 and seals between the plate-like members 50A. The second sealing portion 80b is guided into the interior of the gap G on the side of the metal plate 20B along the chamfered shape of the end portion in the Z direction of the end face 50d and the top end portion of the wall portion 62a. The gap G on the side of the metal plate 20B is blocked by the second sealing portion 80b. Here, since the second sealing portion 80b enters the gap G, a situation in which the second sealing portion 80b wets and spreads excessively on the metal plate 20B and causes a decrease in conductivity is also suppressed. Through the above, the space between the adjacent plate-like members 50A is hermetically sealed by the second sealing portion 80b.

[0086] In the exposed surface 20d of the other surface 20b of the metal plate 20B, the portion corresponding to the gap G on the side of the metal plate 20B becomes a non-contact region 20f. The second sealing portion 80b is provided along the connecting portion 60 between the adjacent plate-like members 50A on either the side of the metal plate 20A or the side of the metal plate 20B. The second sealing portion 80b adheres to each of the plate-like members 50A and the non-contact region 20f among the adjacent plate-like members 50A on either the side of the metal plate 20A or the side of the metal plate 20B, and is filled between each of the plate-like members 50A and the non-contact region 20f among the adjacent plate-like members 50A. Here, the second sealing portion 80b on the side of the metal plate 20A and the second sealing portion 80b on the side of the metal plate 20B are separated from each other and are discontinuous. Specifically, the second sealing portion 80b adheres to the end portion in the Z direction of the end face 50d, the top end portion of the wall portion 62a, and the non-contact region 20f, and is filled between them. The end portion in the Z direction of the end face 50d and the top end portion of the wall portion 62a are portions that form the respective edges of the plate-like members 50A at the end portion in the stacking direction D of the connecting portion 60.

[0087] Refer to Figure 10 to describe the method of sealing between the secondary battery module 4 and the conductive plate 5A by the first sealing portion 80a. In Figure 10 , a state in which the conductive plate 5A and the detection element 70 are stacked on the secondary battery module 4 is shown. The conductive plate 5A and the detection element 70 are connected to each other. As described above, the end face of the short side 5d (refer to Figure 3 ) of the conductive plate 5A to which the detection element 70 is connected and the end face on the side of the short side 5e (refer to Figure 3 ) do not overlap with the first closing portion 21 when viewed from the Z direction. As Figure 10As shown, the first sealing portion 80a extends from the inner edge 21c of the first closing portion 21 in the metal plate 20A to a position corresponding to the connecting portion 60 formed between the detection element 70 and the conductive plate 5A, and is joined to the conductive plate 5A. Thereby, the space between the power storage module 4 and the conductive plate 5A is hermetically sealed by the first sealing portion 80a. The first sealing portion 80a is adhered to the conductive plate 5A and the non-contact region 20f, fills the space between the conductive plate 5A and the non-contact region 20f, and hermetically seals the space between the conductive plate 5A and the exposed surface 20d.

[0088] As an example, the sealing member 80 includes modified silicone, but the modified silicone does not adhere to polyolefin-based plastic raw materials such as polypropylene (PP) with a low surface free energy (polarity). That is, the sealing member 80 including modified silicone does not join with the detection element 70 including such a resin material. In addition, the adhesion by the sealing member 80 is achieved by the anchoring effect brought about by the sealing member 80 biting into the irregularities on the surface and physical interaction (intermolecular force).

[0089] The first sealing portion 80a may be in a shape that has been wetted and diffused on the metal plate 20A by laminating the conductive plate 5A and the detection element 70 on the metal plate 20A, or may be applied to the metal plate 20A in a shape that has been pre-wetted and diffused. By causing the first sealing portion 80a to enter the gap G on the side of the metal plate 20A formed at the end in the Z direction of the connecting portion 60, the situation where the first sealing portion 80a is wetted and diffused more than necessary on the metal plate 20A and the conductivity is reduced can be suppressed.

[0090] As described above, in the power storage device 1, the metal plates 20A and 20B disposed at the stacked ends of the electrode laminate 11 have exposed surfaces 20d exposed from the first closing portion 21. The exposed surfaces 20d have a contact region 20e that contacts and is electrically connected to the conductive plate 5, and a non-contact region 20f that does not contact the conductive plate 5. The first sealing portion 80a of the sealing member 80 is disposed along the inner edge 21c in contact with the first closing portion 21. The first sealing portion 80a fills the space between the conductive plate 5 and the non-contact region 20f, and hermetically seals the space between the conductive plate 5 and the exposed surface 20d. Therefore, it is possible to suppress the intrusion of air or moisture containing moisture from the outside between the exposed surfaces 20d of the metal plates 20A and 20B and the conductive plate 5. As a result, the generation and development of rust in the metal plates 20A and 20B can be suppressed.

[0091] The conductive plate 5A has a plurality of plate-like members 50 connected to each other. The second sealing portion 80b of the sealing member 80 is provided along the connecting portion 60 between the mutually adjacent plate-like members 50 in the exposed surfaces 20d of the metal plates 20A and 20B. The second sealing portion 80b is bonded to each of the mutually adjacent plate-like members 50 and the non-contact region 20f, and is filled between each of the mutually adjacent plate-like members 50 and the non-contact region 20f, and seals between the conductive plate 5 and the exposed surface 20d. Thus, since the second sealing portion 80b is filled into the gap G, it is possible to suppress moisture from invading between the exposed surface 20d of the metal plates 20A and 20B and the conductive plate 5A. As a result, even when the conductive plate 5A includes the connected plate-like members 50, it is possible to suppress the generation and development of rust in the metal plates 20A and 20B. In addition, since the sealing member 80 is filled into the gap G to block the gap G, for example, the situation where the metal plates 20A and 20B enter the gap G due to the internal pressure change of the power storage module 4 is suppressed.

[0092] At the end of the connecting portion 60 in the Z direction, the interval between the mutually adjacent plate-like members 50 becomes larger as it approaches the metal plates 20A and 20B. Thus, since the entrance of the gap G is enlarged, the sealing member 80 can easily be filled into the gap G between the plate-like members 50 constituting the conductive plate 5A. For example, even when the position accuracy at the time of setting the sealing member 80 is low, the sealing member 80 can enter the inside of the gap G and block the gap G.

[0093] When viewed from the Z direction, the first closing portion 21 overlaps with a pair of long sides 5b and 5c which are a part of the outer edge of the conductive plate 5. Thus, it is possible to suppress damage to the metal plates 20A and 20B due to contact with the pair of long sides 5b and 5c of the conductive plate 5.

[0094] The first sealing portion 80a extends from the inner edge 21c of the first closing portion 21 in the metal plates 20A and 20B to a position corresponding to the connecting portion 60 between the detection element 70 and the conductive plate 5A. Therefore, for example, the situation where the metal plates 20A and 20B enter the gap between the detection element 70 and the conductive plate 5A due to the internal pressure change of the power storage module 4 is suppressed. In the present embodiment, the first closing portion 21 provided on the pair of short sides 5d and 5e sides of the detection element 70 extends to the inside more than the first closing portion 21 on the pair of long sides 5b and 5c sides. Therefore, the distance from the inner edge 21c of the first closing portion 21 to the position corresponding to the connecting portion 60 between the detection element 70 and the conductive plate 5A is shortened. Thus, the coating amount of the sealing member 80 can be reduced.

[0095] As described above, the power storage device 1 of the embodiment has been described, but the present invention is not limited to the above embodiment.

[0096] Figure 11A and Figure 11B is a sectional view for explaining another method of closing between the plate-like members 50A by the second sealing portion 80b. In Figure 11A , a state before the plate-like members 50 are connected is shown. In Figure 11B , a state after the plate-like members 50 are connected is shown. As Figure 11A shown, the second sealing portion 80b is provided in each recess 62 of the plate-like member 50 before connection. Next, as Figure 11B shown, the plate-like members 50 are connected to each other to form the conductive plate 5A. Since the convex portion 61 and the recess 62 are joined by the second sealing portion 80b, it is possible to close between the plate-like members 50.

[0097] By connecting the plate-like members 50 to each other, the second sealing portion 80b is extruded from the recess 62. As a result, the second sealing portion 80b leaks to one surface 5f and the other surface 5g of the conductive plate 5A. By disposing the conductive plate 5A on the power storage module 4 in a state where the second sealing portion 80b has leaked, in the metal plate 20A, the second sealing portion 80b is provided at a position corresponding to the connection portion 60. Although not shown, by stacking the power storage module 4 on the conductive plate 5A, in the metal plate 20B, the second sealing portion 80b is also provided at a position corresponding to the connection portion 60. Therefore, for example, the situation where the metal plates 20A and 20B enter the gap G due to the change in the internal pressure of the power storage module 4 is suppressed.

[0098] In this case, the second sealing portion 80b is also provided along the connection portion 60 between the mutually adjacent plate-like members 50A on either the metal plate 20A side or the metal plate 20B side. The second sealing portion 80b adheres to each of the mutually adjacent plate-like members 50A and the non-contact region 20f on either the metal plate 20A side or the metal plate 20B side, and is filled between each of the mutually adjacent plate-like members 50A and the non-contact region 20f. Here, the second sealing portion 80b on the metal plate 20A side and the second sealing portion 80b on the metal plate 20B side are continuous with each other. That is, it can be said that one second sealing portion 80b is filled in the whole between the mutually adjacent plate-like members 50 and is continuously provided from one surface 5f to the other surface 5g. With this configuration, it is possible to further suppress the generation and development of rust in the metal plates 20A and 20B.

[0099] In an embodiment, when viewed from the Z direction, the first closed portion 21 overlaps with a pair of long sides 5b and 5c that form a part of the outer edge of the conductive plate 5. However, the first closed portion 21 may not overlap with a pair of short sides 5d and 5e that form other parts of the outer edge of the conductive plate 5. In this case, it is also possible to suppress damage to the metal plates 20A and 20B due to contact with the pair of short sides 5d and 5e of the conductive plate 5. Moreover, in this case, in the metal plates 20A and 20B, the first closed portion 21 is provided at a position corresponding to the connecting portion 60 between the detection element 70 and the conductive plate 5A. Therefore, there is no need to provide a sealing member 80 at this position.

Claims

1. A power storage device includes a power storage module, a conductive plate stacked on the power storage module, and a sealing member disposed between the conductive plate and the power storage module, characterized in that the power storage module has: an electrode laminate having a plurality of stacked metal plates; and an enclosure disposed so as to surround the side surfaces of the electrode laminate, forming an internal space between adjacent electrodes and enclosing the internal space, the plurality of metal plates include: a metal plate of a negative terminal electrode; a metal plate of a positive terminal electrode; and metal plates of a plurality of bipolar electrodes disposed between the negative terminal electrode and the positive terminal electrode, the enclosure has a plurality of frame-shaped resin portions respectively provided at the edge portions of the plurality of metal plates included in the electrode laminate, the metal plate at the stacked end of the electrode laminate has an exposed surface exposed from the resin portion, the exposed surface has a contact area in contact with the conductive plate and a non-contact area not in contact with the conductive plate, the sealing member has a first sealing portion that is disposed along the inner edge of the resin portion in contact with the resin portion, adhered to the conductive plate and the non-contact area, filled between the conductive plate and the non-contact area, and seals between the conductive plate and the exposed surface, the conductive plate has a plurality of plate-like members connected to each other, the sealing member has a second sealing portion that is disposed along the connection portion formed between adjacent plate-like members, adhered to each of the adjacent plate-like members and the non-contact area, filled between each of the adjacent plate-like members and the non-contact area, and seals between the conductive plate and the exposed surface.

2. The power storage device according to claim 1, wherein the conductive plate has one surface and another surface in the stacking direction of the electrode laminate, the second sealing portion is filled between adjacent plate-like members and is continuously provided from the one surface to the another surface.

3. The power storage device according to claim 1 or 2, wherein at the end of the connection portion in the stacking direction of the electrode laminate, the interval between adjacent plate-like members becomes larger as it approaches the metal plate at the stacked end.

4. The power storage device according to claim 1 or 2, wherein the sealing member is a liquid gasket.

5. The power storage device according to claim 1 or 2, wherein when viewed in the stacking direction of the electrode laminate, the resin portion overlaps with the outer edge of the conductive plate.

6. The power storage device according to claim 1 or 2, wherein it further includes a detection element connected to the end surface of the conductive plate, the first sealing portion extends from the inner edge to a position corresponding to the connection portion formed between the detection element and the conductive plate in the metal plate at the stacked end.

Images