JP6923007B2 - Power storage device - Google Patents

Description

The present invention relates to a power storage device.

An all-solid-state battery is mentioned as a kind of power storage device. The following Patent Document 1 discloses an embodiment in which a plurality of laminated batteries are stacked via a positive electrode current collector foil and a negative electrode current collector foil. These laminated batteries are connected in parallel with each other and sealed with a mold resin.

Japanese Unexamined Patent Publication No. 2014-116156

In Patent Document 1, each positive electrode current collector foil (each negative electrode current collector foil) is welded to a positive electrode terminal (negative electrode terminal) before being sealed with a mold resin. In order to carry out this welding, a process of preparing a jig for mounting each positive electrode current collecting foil (each negative electrode current collecting foil) and a positive electrode terminal (negative electrode terminal), the jig is arranged at a predetermined position. A step of performing the jig and a step of taking out the jig after welding are required. In the manufacture of power storage devices such as laminated batteries, it is desired to eliminate or simplify the above-mentioned steps to improve productivity.

An object of one aspect of the present invention is to provide a power storage device capable of improving productivity.

The current collector according to one aspect of the present invention has a first electrode laminated body including a plurality of first electrodes laminated along a first direction, and a first storage member having a holding member for holding the plurality of first electrodes. A cell, a first current collector plate adjacent to the first current collector cell along the first direction, a connecting member electrically connected to the first current collector cell via the first current collector plate, and a first current collector. A first welded portion for joining the plate and the connecting member is provided, and the first current collector plate is provided along a second direction intersecting with the first main body portion in contact with the first electrode laminate in the first direction. It has a first protruding portion that protrudes from the edge of the first main body portion, and in the first welded portion, the holding member, the first protruding portion, and the connecting member are sequentially overlapped, and the holding member and the first protruding portion are formed. It is provided on a first region that comes into contact with each other.

According to this power storage device, the first welded portion is provided on a first region in which the holding member, the first protruding portion, and the connecting member are sequentially overlapped, and the holding member and the first protruding portion are in contact with each other. Therefore, the holding member included in the first storage cell and holding the plurality of first electrodes of the first electrode laminate can be used as a pedestal to form the first welded portion. As a result, the preparation step of the jig for forming the first welded portion, the taking-out step of the jig, and the like can be omitted, so that the productivity can be improved.

The first protruding portion is a first base end portion extending along the second direction, and a first tip portion extending along the first direction and located outside the first storage cell in the second direction. It also has a first bent portion that connects the first base end portion and the first tip portion, and the holding member is located between the first electrode laminate and the first tip portion in the second direction, and is the first. It has an outer peripheral surface that comes into contact with the tip portion, and the first welded portion may be provided on the first tip portion. In this case, even when a plurality of storage cells including the first storage cell are arranged without gaps along the first direction, the first welded portion can be easily provided.

The first base end portion may be in close contact with the side surface of the holding member intersecting in the first direction. In this case, since the first base end portion is supported by the holding member, damage to the first protruding portion due to vibration or the like can be suppressed.

Each of the plurality of first electrodes may be a bipolar electrode. In this case, the internal resistance of the first storage cell can be reduced.

The power storage device further includes a plurality of power storage cells including a first power storage cell and a cell stack having a plurality of current collector plates including a first current collector plate, and the cell stack includes a plurality of power storage cells and a plurality of power storage cells. The current collector plates may be arranged alternately along the first direction. In this case, since the number of current collector plates in the cell stack can be reduced, the weight of the power storage device can be reduced.

The holding member may be provided on the outer peripheral surface of the first electrode laminate. In this case, the outer peripheral surface of the first electrode laminate can be protected by the holding member.

The holding member may seal the entire outer peripheral surface of the first electrode laminate. In this case, even when the electrolyte in the first electrode laminate exhibits fluidity, the occurrence of a short circuit via the electrolyte can be satisfactorily suppressed by the holding member.

The holding member has a thin-walled portion and a thick-walled portion thicker than the thin-walled portion, and the thick-walled portion may overlap at least the first region and come into contact with the first protruding portion. In this case, the weight of the power storage device can be reduced.

The thin-walled portion is a holding portion that holds a plurality of first electrodes, and the thick-walled portion may have a heat-resistant portion that is in close contact with a part of the holding portion. In this case, when the first welded portion is formed, it is possible to prevent the portion of the holding member that overlaps the first welded portion from being damaged.

The current collector has a second electrode laminate including a plurality of second electrodes laminated along the first direction, and includes a second storage cell arranged along with the first storage cell along the first direction. A second current collector plate adjacent to the second current collector cell along the first direction, a second welded portion for joining the second current collector plate and the connecting member, and the first current collector cell and the first storage cell along the first direction. A restraining member that applies a binding force to the two storage cells and an insulating buffer member arranged between the second storage cell and the restraining member are further provided, and the second current collector plate is formed on the second electrode laminate. It has a second main body portion that comes into contact with the second main body portion and a second protruding portion that protrudes from the edge of the second main body portion along the first direction, and the second main body portion is between the second electrode laminate and the insulating buffer member. The second welded portion is provided on a second region in which the insulating buffer member, the second protruding portion, and the connecting member are sequentially overlapped with each other, and the insulating buffer member and the second protruding portion are in contact with each other. good. In this case, the insulating buffer member can be used as a pedestal when forming the second welded portion. As a result, the process of preparing the jig for forming the second welded portion, the process of taking out the jig, and the like can be omitted.

The second protruding portion includes a second base end portion extending along the second direction, a second tip portion extending along the first direction away from the second storage cell, and a second base end portion. It has a second bent portion that connects the second tip portion and the second bent portion, and the insulating buffer member intersects in the second direction and comes into contact with the second main body portion along the main surface and the edge of the main surface along the first direction. It has an outer peripheral surface that extends and comes into contact with the second tip portion, and the second welded portion may be provided at the second tip portion. In this case, even when the second storage cell, the second current collector plate, and the insulating buffer member are arranged in order along the first direction without a gap, the second welded portion can be easily provided. Can be done.

The second base end portion may be in close contact with the main surface of the insulating buffer member. In this case, since the second base end portion is supported by the insulating buffer member, damage to the second protruding portion due to vibration or the like can be suppressed.

The power storage device according to another aspect of the present invention includes a cell stack having a plurality of power storage cells arranged along the first direction in the horizontal direction, and a pair of storage cells sandwiching the plurality of power storage cells along the first direction. A restraining member and a battery pack accommodating a plurality of storage cells are provided, and each of the plurality of storage cells is erected along a second direction intersecting in the horizontal direction and stacked along the first direction. It has a plurality of bipolar electrodes and a holding member for holding the plurality of bipolar electrodes, and in each of the plurality of storage cells, the dimensions along the third direction intersecting the first direction in the horizontal direction are set to the first direction. It is longer than either the along dimension and the dimension along the second direction, and the area of the surface intersecting the second direction in the cell stack is larger than any of the other surfaces contained in the cell stack.

According to this power storage device, each of the plurality of power storage cells sandwiched between the pair of restraint members is erected along a second direction intersecting in the horizontal direction. Therefore, a plurality of power storage cells can be sandwiched between a pair of restraining members in a vertically placed state. As a result, the storage cells are easily restrained from each other, so that the productivity can be improved. In addition, since the restraint member can be miniaturized, the power storage device can be miniaturized. Further, in each of the plurality of storage cells, the dimension along the third direction in the horizontal direction is longer than both the dimension along the first direction and the dimension along the second direction. Further, the area of the surfaces intersecting in the second direction in the cell stack is larger than any of the other surfaces included in the cell stack. As a result, the capacity of the power storage device can be secured while suppressing the height of the battery pack.

Each of the plurality of storage cells may be arranged on the bottom surface of the battery pack. In this case, a plurality of storage cells can be stably arranged in the battery pack.

The thickness of the portion of the holding member located between the bipolar electrode and the bottom surface of the battery pack may be the largest. In this case, it is possible to suppress the occurrence of a short circuit between the power storage device and the bottom surface of the battery pack or the liquid collected on the bottom surface.

The cell stack has a positive electrode current collecting plate and a negative electrode current collecting plate, and the positive electrode current collecting plate is a positive electrode main body portion that contacts the positive electrode terminals of the first storage cell included in the plurality of storage cells, and along the second direction. The negative electrode current collector plate has a positive electrode protruding portion protruding from the edge of the positive electrode main body portion, and the negative electrode current collecting plate protrudes from the negative electrode main body portion in contact with the negative electrode terminal of the first storage cell and from the edge of the negative electrode main body portion along the second direction. The positive electrode protruding portion and the negative electrode protruding portion may be separated from each other in the third direction. In this case, even if both the positive electrode protruding portion and the negative electrode protruding portion are located on one side of the first storage cell in the second direction, it is possible to prevent the positive electrode protruding portion and the negative electrode protruding portion from being short-circuited.

The dimension of the positive electrode protrusion along the third direction and the dimension of the negative electrode protrusion along the third direction may be less than half of the dimension of the first storage cell along the third direction. In this case, it is possible to more reliably prevent both the positive electrode protruding portion and the negative electrode protruding portion from being short-circuited.

The power storage device further includes a first connecting member welded to the positive electrode protruding portion in the second direction and a second connecting member welded to the negative electrode protruding portion in the second direction, and the first connecting member and the second Each of the connecting members may be located on one side of the first storage cell in the second direction. In this case, the welding of the first connecting member to the positive electrode protruding portion and the welding of the second connecting member to the negative electrode protruding portion can be performed in one step, so that the productivity can be further improved.

The edge of the positive electrode body portion has a first edge portion that intersects in the second direction and is connected to the positive electrode protruding portion, and a second edge portion that is located on the opposite side of the first edge portion in the second direction, and has a negative electrode body portion. Has a third edge that intersects in the second direction and connects to the negative electrode protrusion, and a fourth edge that is located on the opposite side of the third edge in the second direction, the second edge and the second. Each of the four edges may be located inside the outer peripheral surface of the holding member. In this case, the positive electrode main body portion is less likely to be short-circuited via the second edge portion, and the negative electrode main body portion is less likely to be short-circuited via the fourth edge portion.

Each of the positive electrode main body and the negative electrode main body may overlap with the first storage cell in the first direction and may not overlap with the holding member. In this case, the load applied from the restraint member to the electrode laminate of the first storage cell along the first direction is satisfactorily applied without being dispersed from the positive electrode main body and the negative electrode main body to the holding member.

Each of the pair of restraint members extends along the first direction from one end of the main portion that applies a load to a plurality of storage cells along the first direction and the main portion located on the bottom surface side of the battery pack. The extending portion may be fixed to the bottom surface of the battery pack. In this case, since the pair of restraint members in the battery pack can be positioned, a plurality of storage cells can be stably arranged in the battery pack.

The power storage device further includes a cover member that regulates the movement of the plurality of power storage cells in the second direction, and the cover member and at least one of the pair of restraint members may be integrated.

In the second direction, the plurality of storage cells may be located between the cover member and the bottom surface of the battery pack. In this case, even if the shape of the cover member does not surround the plurality of power storage cells, the position of the power storage cells can be satisfactorily determined in the battery pack.

According to one aspect of the present invention, it is possible to provide a power storage device capable of improving productivity.

FIG. 1 is a schematic perspective view showing a power storage device according to the first embodiment. FIG. 2A is a schematic perspective view of the power storage cell and the current collector plate in contact with the power storage cell, and FIG. 2B is a schematic side view of the power storage cell and the current collector plate in contact with the power storage cell. be. FIG. 3 is a schematic cross-sectional view of the power storage cell. FIG. 4 is an enlarged view of the area surrounded by the broken line shown in FIG. 5 (a) is a schematic cross-sectional view taken along the line Va-Va of FIG. 1, and FIG. 5 (b) is a schematic plan view of the connecting member shown in FIG. 5 (a). 6 (a) is a schematic cross-sectional view taken along the line VIa-VIa of FIG. 1, and FIG. 6 (b) is a schematic plan view of the connecting member shown in FIG. 6 (a). FIG. 7 is a schematic cross-sectional view showing a usage example of the power storage device according to the first embodiment. FIG. 8 is a schematic cross-sectional view of a main part of the power storage device shown in FIG. FIG. 9A is a schematic cross-sectional view of a main part showing the power storage device of the first modification of the first embodiment, and FIG. 9B shows the power storage device of the second modification of the first embodiment. It is a schematic cross-sectional view of a main part. FIG. 10A is a schematic perspective view of the first storage cell and the current collector plate in contact with the first storage cell, and FIG. 10B is a schematic perspective view of the first storage cell and the first storage cell in contact with the first storage cell. It is a schematic side view of a current collector plate. FIG. 11A is a schematic perspective view of the second storage cell and the current collector plate in contact with the second storage cell, and FIG. 11B is a schematic perspective view of the second storage cell and the second storage cell in contact with the second storage cell. It is a schematic side view of a current collector plate. FIG. 12 is a schematic cross-sectional view of a main part showing the power storage device of the second embodiment. FIG. 13 is a schematic cross-sectional view of a main part showing the power storage device of the third embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate description is omitted. The dimensional ratios in the drawings do not always match those described.

(First Embodiment)
FIG. 1 is a schematic perspective view showing a power storage device according to the first embodiment. The power storage device 1 shown in FIG. 1 is a power storage module used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 includes a cell stack 2, connecting members 3 and 4 electrically connected to the cell stack 2, a pair of restraint members 5 and 6 for restraining the cell stack 2, and a cell stack 2 and a restraint member 5. An insulating buffer member 7 arranged between the cells, an insulating buffer member 8 arranged between the cell stack 2 and the restraint member 6, and a cover member 9 covering a part of the cell stack 2 are provided. In the following, the direction in which the restraint members 5 and 6 restrain the cell stack 2 is the direction X (first direction) shown in FIG. 1, and the direction intersecting or orthogonal to the direction X in the horizontal direction is the direction Y (third direction). The direction that intersects or is orthogonal to the direction X and the direction Y (that is, the direction that intersects or is orthogonal to the horizontal direction) is defined as the direction Z (second direction). The power storage device 1 may be provided with a base on which the cell stack 2 or the like is placed, or may be provided with a case (battery pack) in which the cell stack 2 or the like is housed.

The cell stack 2 has a plurality of storage cells 11 arranged vertically along the direction X. That is, the cell stack 2 is an aggregate of a plurality of storage cells 11. The cell stack 2 exhibits, for example, a substantially rectangular parallelepiped shape. The area of the faces intersecting the direction Z in the cell stack 2 is larger than any of the other faces included in the cell stack 2. Other surfaces included in the cell stack 2 include a surface that intersects the direction X in the cell stack 2 and a surface that intersects the direction Y in the cell stack 2. The area of the surface intersecting the direction Z in the cell stack 2 corresponds to, for example, the product of the dimensions along the directions X and Y of the cell stack 2. Similarly, the area of the surface intersecting the direction X in the cell stack 2 corresponds to, for example, the product of the dimensions along the directions Y and Z of the cell stack 2. The cell stack 2 includes, for example, 89 or more and 111 or less storage cells 11. In the first embodiment, the cell stack 2 includes 100 storage cells. Details of the configuration of the power storage cell 11 will be described later. The cell stack 2 also has a plurality of current collector plates, although not shown in FIG. The details of the current collector plate will also be described later.

The connecting member (first connecting member) 3 is a conductive member (bus bar) that functions as a positive electrode of the power storage device 1, and has a substantially flat plate shape. The connecting member 3 is provided on one end side of the cell stack 2 in the direction Y and on one side of the cell stack 2 (storage cell 11) in the direction Z. The connecting member 3 is, for example, a metal plate or an alloy plate. The metal plate is, for example, a copper plate, an aluminum plate, a titanium plate, or a nickel plate. The alloy plate is, for example, a stainless steel plate (SUS301, SUS304, etc.) or an alloy plate of the above metal. The connecting member 3 extends along the direction X and protrudes along the direction X from the main plate portion 3a that overlaps the cell stack 2 and the insulating buffer member 7 in the direction Z and one end of the main plate portion 3a on the restraining member 5 side. It has a protruding plate portion 3b. The main plate portion 3a of the connecting member 3 is electrically connected to each positive electrode terminal of a plurality of storage cells 11 included in the cell stack 2. The protruding plate portion 3b of the connecting member 3 is continuously provided on the main plate portion 3a. The end of the protruding plate portion 3b along the direction X is located outside the restraining member 5. The connecting member 3 is separated from the restraining members 5 and 6.

The connecting member (second connecting member) 4 is a conductive member (bus bar) that functions as a negative electrode of the power storage device 1, and has a substantially flat plate shape. The connecting member 4 is provided on the other end side of the cell stack 2 in the direction Y, and is provided on one side of the cell stack 2 (storage cell 11) in the direction Z. Like the connecting member 3, the connecting member 4 is, for example, a metal plate or an alloy plate. The connecting member 4 may be the same metal plate or alloy plate as the connecting member 3, or may be a different metal plate or alloy plate. The connecting member 4 extends along the direction X and protrudes along the direction X from the main plate portion 4a that overlaps the cell stack 2 and the insulating buffer member 8 in the direction Z and one end of the main plate portion 4a on the restraining member 6 side. It has a protruding plate portion 4b. The protruding plate portion 4b is provided on the side opposite to the protruding plate portion 3b of the connecting member 3 in the direction X. The main plate portion 4a of the connecting member 4 is electrically connected to each negative electrode terminal of a plurality of storage cells 11 included in the cell stack 2. The protruding plate portion 4b of the connecting member 4 is continuously provided on the main plate portion 4a. The end of the protruding plate portion 4b along the direction X is located outside the restraining member 6. The connecting member 4 is separated from the restraining members 5 and 6 in the same manner as the connecting member 3.

Each of the restraint members 5 and 6 is a member that applies a restraint force (restraint load) along the direction X to the cell stack 2, and is an end plate having a substantially L-shaped plate shape. The restraint member 5 is arranged on one end side of the cell stack 2 in the direction X, and is arranged along the direction X from one end of the main portion 5a that applies a restraint load to the cell stack 2 and the main portion 5a in the direction Z. It has an extending portion 5b and an extending portion 5b. The area of the main portion 5a viewed from the direction X is equal to or larger than the area of the surface intersecting the direction X in the cell stack 2 (the surface located at one end of the cell stack 2). In the first embodiment, the surfaces intersecting the direction X in the cell stack 2 completely overlap the main portion 5a in the direction X. Therefore, the main portion 5a applies a restraining load to the entire surface intersecting the direction X in the cell stack 2. The extending portion 5b extends away from the cell stack 2. The restraint member 6 is arranged on the other end side of the cell stack 2 in the direction X, and is arranged along the direction X from one end of the main portion 6a that applies a restraint load to the cell stack 2 and the main portion 6a in the direction Z. It has an extending portion 6b that extends. The area of the main portion 6a viewed from the direction X is equal to or larger than the area of the surface intersecting the direction X in the cell stack 2, similarly to the main portion 5a. In the first embodiment, the surfaces intersecting the direction X in the cell stack 2 completely overlap the main portion 6a in the direction X, and the main portion 6a is the entire surface intersecting the direction X in the cell stack 2. A restraining load is applied to the load. The extending portion 6b extends away from the cell stack 2 in the same manner as the extending portion 5b of the restraining member 5. Each of the restraint members 5 and 6 is, for example, a plate material made of metal or alloy. The restraining members 5 and 6 may be connected to each other via a connecting member using, for example, a fastening member (for example, a bolt and a nut). In this case, each of the restraint members 5 and 6 may be provided with a through hole or the like through which a connecting member such as a bolt extending along the direction X is inserted. Alternatively, each of the restraint members 5 and 6 may be fixed to a base or a case (battery pack) (not shown) or the like. In this case, each of the restraint members 5 and 6 may be provided with a through hole or the like through which a member for fixing them to a base or the like is inserted.

Each of the insulating buffer members 7 and 8 is an insulating member for absorbing the expansion of the power storage cell 11, and has a substantially rectangular parallelepiped shape. The insulating buffer member 7 is arranged between the cell stack 2 and the restraint member 5 in the direction X. The insulating buffer member 8 is arranged between the cell stack 2 and the restraint member 6 in the direction X. The end faces of the insulating buffer members 7 and 8 facing the connecting members 3 and 4 may be aligned with each other of the cell stack 2 with respect to the end faces facing the connecting members 3 and 4. That is, the end faces may be flush with each other. Each of the insulating buffer members 7 and 8 contains, for example, polypropylene (PP), polyphenylene sulfide (PPS), and nylon 66 (PA66). At least one of the insulating buffer members 7 and 8 may exhibit elasticity. The length (that is, the thickness) of the insulating buffer members 7 and 8 along the direction X is, for example, 1 mm or more and 10 mm or less. In the first embodiment, the thickness of the insulating buffer members 7 and 8 is 5 mm.

The cover member 9 is a member for restricting the movement of the power storage cell 11 in the direction Z, and has a substantially inverted U-shaped plate shape. The cover member 9 is provided between the connecting members 3 and 4 in the direction Y, and is separated from the connecting members 3 and 4. The cover member 9 includes a cover portion 9a extending along the direction X, a first mounting portion 9b extending along the direction Z from one end of the cover portion 9a in the direction X, and a cover portion 9a in the direction X. It has a second mounting portion 9c extending from the end along the direction Z. The first mounting portion 9b is fixed to the restraining member 5 via a fastening member E or the like. The second mounting portion 9c is fixed to the restraining member 6 via a fastening member or the like, similarly to the first mounting portion 9b. Therefore, in the first embodiment, the cover member 9 functions as a connecting member for connecting the restraining members 5 and 6. The cover member 9 is, for example, a metal plate or an alloy plate. The cover member 9 and at least one of the restraint members 5 and 6 may be integrated. In this case, the number of fastening members E can be reduced.

Next, the details of the storage cell 11 and the current collector plate included in the cell stack 2 will be described with reference to FIGS. 2 to 4. First, the details of the configuration of the power storage cell 11 will be described. FIG. 2A is a schematic perspective view of the power storage cell and the current collector plate in contact with the power storage cell, and FIG. 2B is a schematic side view of the power storage cell and the current collector plate in contact with the power storage cell. be. FIG. 3 is a schematic cross-sectional view of the power storage cell. FIG. 4 is an enlarged view of the area surrounded by the broken line shown in FIG.

As shown in FIGS. 2A and 2B, the power storage cell 11 is a cell cell having a substantially rectangular parallelepiped shape, and is erected along the direction Z. In the storage cell 11, the side along the direction X is the shortest, and the side along the direction Y is the longest. In other words, in the power storage cell 11, the dimension D1 along the direction Y is longer than both the dimension D2 along the direction Z and the dimension (thickness) D3 along the direction X. The storage cell 11 is a secondary battery such as a nickel hydrogen secondary battery or a lithium ion secondary battery. The storage cell 11 may be an electric double layer capacitor. The power storage cell 11 may be an all-solid-state battery. In the first embodiment, the storage cell 11 is a bipolar lithium ion secondary battery. The power storage cell 11 is sandwiched between the positive electrode current collector plate 12 and the negative electrode current collector plate 13 in the direction X, is electrically connected to the connecting member 3 via the positive electrode current collector plate 12, and is also a negative electrode current collector plate. It is electrically connected to the connecting member 4 via 13. The storage cell 11 has an electrode laminate 14 having a pair of main surfaces 14a and 14b intersecting in the direction X and an outer peripheral surface 14c connecting the main surfaces 14a and 14b, and a holding provided on at least the outer peripheral surface 14c of the electrode laminate 14. It includes a member 15.

As shown in FIGS. 3 and 4, the electrode laminate 14 has a plurality of bipolar electrodes 16 (a plurality of first electrodes) and a plurality of separators 17. The plurality of bipolar electrodes 16 and the plurality of separators 17 are alternately arranged along the direction X.

Each of the plurality of bipolar electrodes 16 includes a current collector 21, a positive electrode layer 22, and a negative electrode layer 23. The current collector 21 has a pair of main surfaces 21a and 21b that intersect in the direction X. A positive electrode layer 22 is provided on the main surface 21a of the current collector 21, and a negative electrode layer 23 is provided on the main surface 21b of the current collector 21. Therefore, the current collector 21 is sandwiched between the positive electrode layer 22 and the negative electrode layer 23 along the direction X.

The current collector 21 is a sheet-shaped conductive member and has a substantially rectangular shape. The current collector 21 is, for example, a metal foil or an alloy foil. The metal foil is, for example, copper foil, aluminum foil, titanium foil, or nickel foil. When the current collector 21 is a metal foil, the metal foil may be an aluminum foil from the viewpoint of ensuring mechanical strength. The alloy foil is, for example, a stainless steel foil (SUS301, SUS304, etc.) or an alloy foil of the above metal. When the current collector 21 is an alloy foil, or when the current collector 21 is a metal foil other than the aluminum foil, the surface of the current collector 21 may be coated with aluminum. The thickness of the current collector 21 is, for example, 5 μm or more and 20 μm or less. In the first embodiment, the thickness of the current collector 21 is 10 μm.

The positive electrode layer 22 is a layered member containing a positive electrode active material and an electrolyte, and has a substantially rectangular shape. The positive electrode active material of the first embodiment is, for example, a composite oxide, metallic lithium, sulfur and the like. The composition of the composite oxide includes, for example, at least one of manganese, titanium, nickel, cobalt, and aluminum, and lithium. The electrolyte is, for example, a liquid electrolyte, a solid electrolyte, a solid polymer electrolyte, or a gel electrolyte. The solid electrolyte contains zirconia or β-alumina. The solid polymer electrolyte contains, for example, an alkylene oxide-based polymer compound such as polyethylene oxide (PEO) and polypropylene oxide (PPO), or a copolymer thereof. In addition, when the positive electrode layer 22 contains a solid polymer electrolyte, the positive electrode layer 22 may contain, for example, a supporting salt for increasing ionic conductivity, a conductive auxiliary agent for increasing electron conductivity, a viscosity adjusting solvent, and a polymerization initiator. Includes at least one. The supporting salt is, for example, a lithium salt from the viewpoint of being easily soluble in an alkylene oxide-based polymer compound. Lithium salts are, for example, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof. The conductive auxiliary agent is, for example, acetylene black, carbon black, graphite or the like. The viscosity adjusting solvent is, for example, N-methyl-2-pyrrolidone (NMP) or the like. The polymerization initiator is, for example, azobisisobutyronitrile (AIBN) or the like. Gel-like electrolytes do not show complete or almost complete fluidity. For example, the viscosity of the gel electrolyte at 20 ° C. is 0.1 Pa · S or more.

The negative electrode layer 23 is a layered member containing a negative electrode active material and an electrolyte, and has a substantially rectangular shape. The negative electrode active material of the first embodiment can be alloyed with, for example, graphite, highly oriented graphite, mesocarbon microbeads, carbon such as hard carbon and soft carbon, alkali metals such as lithium and sodium, metal compounds, and lithium. Elements (eg, silicon, tin, etc.) and their compounds, boron-added carbon, and the like. As the electrolyte of the negative electrode layer 23, the same electrolyte as that contained in the positive electrode layer 22 is used.

The separator 17 is a layered member that separates adjacent bipolar electrodes 16 from each other, and has a substantially rectangular shape. The separator 17 is composed of the electrolyte contained in the positive electrode layer 22 and the negative electrode layer 23. Alternatively, the separator 17 may be a porous membrane that can be filled with an electrolyte. When the separator 17 is composed of a solid electrolyte, the separator 17 may have a substantially rectangular plate shape. The thickness of the separator 17 is, for example, 1 μm or more and 10 μm or less. In the first embodiment, the thickness of the separator 17 is 5 μm.

Current collectors 21 are provided at both ends of the electrode laminate 14 in the direction X. The negative electrode layer is not arranged on the main surface 21b of the current collector 21 arranged at one end of the electrode laminated body 14 (on the right side of the paper surface in FIG. 3) in the direction X. Therefore, the current collector 21 corresponds to the positive electrode terminal in the electrode laminate 14 (storage cell 11), and the main surface 21b corresponds to the main surface 14a of the electrode laminate 14. The positive electrode layer is not arranged on the main surface 21a of the current collector 21 arranged at the other end of the electrode laminated body 14 (the left side of the paper surface in FIG. 3) in the direction X. Therefore, the current collector 21 corresponds to the negative electrode terminal in the electrode laminate 14 (storage cell 11), and the main surface 21a corresponds to the main surface 14b of the electrode laminate 14.

The holding member 15 is a member that holds a plurality of bipolar electrodes 16, a plurality of separators 17, a positive electrode terminal, and a negative electrode terminal included in the electrode laminate 14, and exhibits insulating properties. In the first embodiment, the holding member 15 has a sealing member having a substantially rectangular frame shape so as to seal the outer peripheral surface 14c of the electrode laminate 14, and a short circuit between the bipolar electrodes 16 in the electrode laminate 14. It can also function as a short-circuit prevention member to prevent. The holding member 15 has an inner peripheral surface 15a that contacts the outer peripheral surface 14c of the electrode laminate 14, an outer peripheral surface 15b that is located on the opposite side of the inner peripheral surface 15a, and a side surface 15c that intersects the direction X. The side surface 15c is provided substantially parallel to the main surfaces 14a and 14b of the electrode laminate 14. In the first embodiment, the side surface 15c located at one end in the direction X (right side of the paper surface in FIG. 3) is flush with the main surface 14a and is located at the other end in the direction X (right side of the paper surface in FIG. 3). The side surface 15c is flush with the main surface 14b. The holding member 15 includes, for example, a resin member exhibiting heat resistance. The resin member exhibiting heat resistance is, for example, polyimide, PP, PPS, PA66 or the like. The thickness T1 of the holding member 15 is, for example, 1 mm or more and 10 mm or less. In this case, it is possible to prevent damage to the holding member 15 due to heat or the like and reduce the weight of the power storage cell 11. The thickness of the holding member 15 corresponds to the distance between the inner peripheral surface 15a and the outer peripheral surface 15b along the direction Y or the direction Z. In the first embodiment, the thickness T1 of the holding member 15 is substantially constant, about 5 mm. Therefore, the dimension along the direction Y of the electrode laminate 14 corresponds to the dimension D1- (thickness T1 × 2), and the dimension along the direction Z of the electrode laminate 14 is the dimension D2- (thickness T1). Corresponds to × 2).

Next, returning to FIGS. 2A and 2B, the configurations of the positive electrode current collector plate 12 and the negative electrode current collector plate 13 will be described. The positive electrode current collector plate 12 and the negative electrode current collector plate 13 shown in FIGS. 2A and 2B are in a state before being arranged in the cell stack 2. Each of the positive electrode current collector plate 12 and the negative electrode current collector plate 13 is subjected to bending or the like before being arranged in the cell stack 2. Details of the positive electrode current collector plate 12 and the negative electrode current collector plate 13 that have been bent or the like will be described later. In the first embodiment, the positive electrode current collector plate 12 and the negative electrode current collector plate 13 have the same dimensions and the same shape. The positive electrode current collector plate 12 and the negative electrode current collector plate 13 may be the same member. Therefore, in the following, only the dimensions of the positive electrode current collector plate 12 will be described, and the dimensions of the negative electrode current collector plate 13 will be omitted.

The positive electrode current collector plate 12 is a conductive member that comes into contact with the electrode laminate 14, and has a plate shape. The positive electrode current collector plate 12 is a conductive member obtained by processing, for example, a metal plate or an alloy plate. The positive electrode current collector plate 12 is adjacent to the storage cell 11 along the direction X. The positive electrode current collector plate 12 has a main body portion (positive electrode main body portion) 12a that contacts the current collector 21 that functions as a positive electrode terminal, and a protruding portion (positive electrode main body portion) that protrudes from a part of the edge 12b of the main body portion 12a along the direction Z. It has a protruding portion) 12c. The main body portion 12a is a portion that overlaps the bipolar electrode 16 and the separator 17 in the direction X, and has a substantially rectangular shape. In the first embodiment, when the positive electrode current collector plate 12 is sandwiched by the two storage cells 11 along the direction X, one surface of the main body 12a comes into contact with one storage cell 11 and the other surface of the main body 12a. Contact the other storage cell 11. At this time, the positive electrode current collector plate 12 is in contact with the positive electrode terminal of each storage cell 11, and is not in contact with the current collector 21 functioning as the negative electrode terminal.

The edge 12b of the main body 12a in the first embodiment is located inside the inner peripheral surface 15a of the holding member 15 when viewed from the direction X. That is, the edge 12b does not overlap the holding member 15 when viewed from the direction X. Therefore, the main body portion 12a is located inside the outer circumference of the storage cell 11 when viewed from the direction X. Specifically, the main body portion 12a is located inside the region defined by the holding member 15 when viewed from the direction X. Therefore, the main body 12a overlaps the power storage cell 11 in the direction X, and does not overlap the holding member 15.

When the length of the main body 12a along the direction Y is the dimension D11 and the length of the main body 12a along the direction Z is the dimension D12, the dimension D11 is less than the dimension D1 and the dimension D12 is less than the dimension D2. be. In the first embodiment, the main body 12a is separated from the holding member 15. In other words, in the first embodiment, the dimension D11 corresponds to the dimension of the electrode laminate 14 along the direction Y (dimension D1- (thickness T1 × 2)) (that is, D11 = D1-T1 × 2). .. Further, the dimension D12 corresponds to the dimension (dimension D2- (thickness T1 × 2)) of the electrode laminate 14 along the direction Z (that is, D12 = D2-T1 × 2). Alternatively, the dimension D11 is less than the dimension (dimension D1- (thickness T1 × 2)) of the electrode laminate 14 along the direction Y (that is, D11 <D1-T1 × 2), and the dimension D12 is the direction Z. It is less than the dimension (dimension D2- (thickness T1 × 2)) of the electrode laminate 14 along with (that is, D12 <D2-T1 × 2). In these cases, it is possible to prevent the restraint load transmitted from the restraint members 5 and 6 to the main body portion 12a along the direction X from being dispersed from the main body portion 12a to the holding member 15. As a result, the restraint load can be satisfactorily transmitted to the electrode laminate 14. The lower limit of each of the dimensions D11 and D12 is, for example, a value at which the main body 12a can apply the restraining load to the entire positive electrode layer 22 and the negative electrode layer 23.

The dimension (protrusion amount) of the protrusion 12c along the direction Z is larger than the thickness T1 of the holding member 15. Further, the dimension of the protruding portion 12c along the direction Z is less than the sum of the thickness T1 and half of the dimension D3 of the storage cell 11. As shown in FIGS. 5 (a) and 10 to be described later, the positive electrode current collector plate 12 can be hooked on the power storage cell 11 by bending the protruding portion 12c. Thereby, when assembling the cell stack 2, each positive electrode current collector plate 12 can be easily positioned. The dimension of the protrusion 12c along the direction Y is less than half of the dimension D1 of the storage cell 11. In the first embodiment, in the direction Y, the dimension of the protrusion 12c is less than half of the dimension of the electrode laminate 14 along the direction Y.

The negative electrode current collector plate 13 is a conductive member that comes into contact with the electrode laminate 14, and has a plate shape. The negative electrode current collector plate 13 is a conductive member obtained by processing, for example, a metal plate or an alloy plate. The negative electrode current collector plate 13 is adjacent to the power storage cell 11 along the direction X like the positive electrode current collector plate 12. The negative electrode current collector plate 13 has a main body portion (negative electrode main body portion) 13a that contacts the current collector 21 that functions as a negative electrode terminal, and a protruding portion (negative electrode) that protrudes from a part of the edge 13b of the main body portion 13a along the direction Z. It has a protruding portion) 13c. The main body 13a is a portion that overlaps the bipolar electrode 16 and the separator 17 in the direction X, and has a substantially rectangular shape. In the first embodiment, when the negative electrode current collector plate 13 is sandwiched by two storage cells 11 along the direction X, one surface of the main body 13a comes into contact with one storage cell 11 and the other surface of the main body 13a. Contact the other storage cell 11. At this time, the negative electrode current collector plate 13 is in contact with the negative electrode terminals of each storage cell 11, and is not in contact with the positive electrode terminals. As described above, in the first embodiment, the positive electrode current collector plate 12 comes into contact with the positive electrode terminals of each storage cell 11. Therefore, in the first embodiment, the plurality of storage cells 11 in the cell stack 2 are connected in parallel via the positive electrode current collector plate 12 and the negative electrode current collector plate 13. Further, in the first embodiment, the edge 13b of the main body portion 13a is located inside the inner peripheral surface 15a of the holding member 15. Therefore, since the main body 13a is located inside the outer periphery of the power storage cell 11 when viewed from the direction X, it overlaps with the power storage cell 11 in the direction X and does not overlap with the holding member 15. In other words, the main body 13a is located inside the region defined by the holding member 15 when viewed from the direction X.

The protruding portion 13c of the negative electrode current collector plate 13 projects along the direction in which the protruding portion 12c of the positive electrode current collector plate 12 protrudes in the direction Z. The protruding portion 13c does not overlap the protruding portion 12c in the direction X, and is provided at a distance from the protruding portion 12c in the direction Y. That is, when viewed from the direction X, the protruding portions 12c and 13c are separated from each other in the direction Y. In the first embodiment, the protruding portion 12c is provided on one end side in the direction Y of the storage cell 11 (on the left side of the paper surface in FIG. 2A), and the protruding portion 13c is provided on the other end side in the direction Y of the storage cell 11 (FIG. 2). In 2 (a), it is provided on the right side of the paper surface). The amount of protrusion of the protruding portions 12c and 13c is at least larger than the thickness of the holding member 15.

5 (a) is a schematic cross-sectional view taken along the line Va-Va of FIG. 1, and FIG. 5 (b) is a schematic plan view of the connecting member 3 shown in FIG. 5 (a). As shown in FIG. 5A, in the cell stack 2, a plurality of storage cells 11 and a plurality of current collector plates are alternately arranged along the direction X. More specifically, the cell stack 2 is formed by arranging the groups arranged in the order of the power storage cell 11, the positive electrode current collector plate 12, the power storage cell 11, and the negative electrode current collector plate 13 continuously along the direction X. ing. A binding force along the direction X is applied to each storage cell 11 and each current collecting plate by the restraining member 5 via the insulating buffer member 7.

The positive electrode current collector plate 12 in contact with the storage cell 11 located on the outermost side in the direction X shown in FIG. 5A is arranged between the power storage cell 11 and the insulating buffer member 7 and is arranged. The main body 12a of the positive electrode current collector plate 12 is in contact with the main surface 7a of the insulating buffer member 7. Hereinafter, the positive electrode current collector plate 12 located on the outermost side in the direction X shown in FIG. 5A is referred to as the outermost positive electrode current collector plate 12A (second current collector plate). The insulating buffer member 7 has a main surface 7a that intersects the direction X and contacts the main body portion 12a, and an outer peripheral surface 7b that extends from the edge of the main surface 7a along the direction X.

The protruding portion 12c of each positive electrode current collector plate 12 in the cell stack 2 is bent. The protruding portion 12c (first protruding portion) of the positive electrode current collecting plate 12 excluding the outermost positive electrode current collecting plate 12A is bent along the side surface 15c and the outer peripheral surface 15b of the holding member 15. The protruding portion 12c of these positive electrode current collector plates 12 extends along the direction Z, the base end portion 12d (first base end portion), extends along the direction X, and is larger than the storage cell 11 in the direction Z. It has a tip portion 12e (first tip portion) located on the outside, and a bent portion 12f (first bent portion) connecting the base end portion 12d and the tip portion 12e. Further, the protruding portion 12c (first or second protruding portion) of the outermost positive electrode current collector plate 12A is bent along the main surface 7a and the outer peripheral surface 7b of the insulating buffer member 7. The protruding portion 12c of the outermost positive electrode current collector plate 12A, like the other positive electrode current collector plates 12, has a base end portion 12d (second base end portion) extending along the direction Z and a direction X. A tip portion 12e (second tip portion) that extends and is located outside the insulating buffer member 7 in the direction Z, and a bent portion 12f (second bent portion) that connects the base end portion 12d and the tip portion 12e. Have.

The base end portion 12d of the projecting portion 12c does not overlap with the electrode laminate 14 in the direction X, and is provided along the side surface 15c of the holding member 15. In the first embodiment, the entire base end portion 12d is in close contact with the side surface 15c of the corresponding holding member 15. In addition, the entire base end portion 12d of the outermost positive electrode current collector plate 12A is in close contact with the main surface 7a of the insulating buffer member 7. Each bent portion 12f is bent so as to be substantially at a right angle when viewed from the direction Y.

The tip portion 12e of the protruding portion 12c of the positive electrode current collector plate 12 (first current collector plate) excluding the outermost positive electrode current collector plate 12A overlaps with the electrode laminate 14 and the connecting member 3 in the direction Z, and is a holding member 15. Extends along the outer peripheral surface 15b of the. In the first embodiment, the entire tip portion 12e is in close contact with both the outer peripheral surface 15b of the holding member 15 and the connecting member 3. Welding is performed on the first region R1 in which the tip portion 12e, the corresponding holding member 15, and the connecting member 3 overlap along the direction Z, and the holding member 15 and the tip portion 12e are in contact with each other. A portion W1 (first welded portion) is provided. The welded portion W1 is a portion for joining the positive electrode current collector plate 12 and the connecting member 3, and is provided at a portion where the tip portion 12e and the connecting member 3 are in contact with each other. The welded portion W1 is formed by, for example, laser welding. When the welded portion W1 is formed, the holding member 15 also functions as a pedestal in the welding process. The length of the tip portion 12e along the direction X is 10% or more and 90% or less of the length of the holding member 15 along the direction X. In this case, a region for forming the welded portion W1 can be secured at the tip portion 12e. In the first embodiment, the length of the tip portion 12e along the direction X is 40% of the length of the holding member 15 along the direction X. Since the tip portion 12e extends along the outer peripheral surface 15b of the holding member 15 as described above, the joining between the tip portion 12e and the connecting member 3 is performed outside the holding member 15.

The tip portion 12e of the protruding portion 12c of the outermost positive electrode current collector plate 12A extends along the direction X so as to be away from the storage cell 11. Therefore, the tip portion 12e overlaps with the insulating buffer member 7 in the direction Z and extends along the outer peripheral surface 7b of the insulating buffer member 7. In the first embodiment, the entire tip portion 12e is in close contact with both the outer peripheral surface 7b of the insulating buffer member 7 and the connecting member 3. A welded portion is formed on a second region R2 in which the tip portion 12e, the insulating buffer member 7, and the connecting member 3 overlap along the direction Z, and the insulating buffer member 7 and the tip portion 12e are in contact with each other. W2 (second welded portion) is provided. The welded portion W2 is a portion that joins the outermost positive electrode current collector plate 12A and the connecting member 3. Like the welded portion W1, the welded portion W2 is formed by, for example, laser welding. When the welded portion W2 is formed, the insulating buffer member 7 also functions as a pedestal in the welding process. The length of the outermost positive electrode current collector plate 12A along the direction X of the tip portion 12e is 10% or more and 90% or less of the thickness of the insulating buffer member 7. In this case, a region for forming the welded portion W2 can be secured at the tip portion 12e. The thickness of the insulating buffer member 7 corresponds to the length of the insulating buffer member 7 along the direction X. In the first embodiment, the length of the tip portion 12e of the outermost positive electrode current collector plate 12A along the direction X is 80% of the thickness of the insulating buffer member 7.

The tip portion 12e of the positive electrode current collector plate 12 excluding the outermost positive electrode current collector plate 12A and the tip portion 12e of the outermost positive electrode current collector plate 12A extend along the same direction. Specifically, the tip portion 12e extends toward one side of the direction X.

6 (a) is a schematic cross-sectional view taken along the line VIa-VIa of FIG. 1, and FIG. 6 (b) is a schematic plan view of the connecting member 4 shown in FIG. 6 (a). The negative electrode current collector plate 13 in contact with the storage cell 11 located on the outermost side in the direction X shown in FIG. 6A is arranged between the storage cell 11 and the insulating buffer member 8 and is said to be the same. The main body 13a of the negative electrode current collector plate 13 is in contact with the main surface 8a of the insulating buffer member 8. Hereinafter, the negative electrode current collector plate 13 located on the outermost side in the direction X shown in FIG. 6A is also referred to as the outermost negative electrode current collector plate 13A.

The protruding portion 13c of each negative electrode current collector plate 13 in the cell stack 2 is bent. The protruding portion 13c of the negative electrode current collector plate 13 excluding the outermost negative electrode current collector plate 13A is bent along the side surface 15c and the outer peripheral surface 15b of the holding member 15. Further, the protruding portion 13c of the outermost negative electrode current collector plate 13A is bent along the main surface 8a and the outer peripheral surface 8b of the insulating buffer member 8. The protruding portion 13c of each negative electrode current collector plate 13 including the outermost negative electrode current collector plate 13A extends from the base end portion 13d extending along the direction Z, extending along the direction X, and from the storage cell 11 in the direction Z. Also has a tip portion 13e located on the outside and a bent portion 13f connecting the base end portion 13d and the tip portion 13e.

The base end portion 13d of the protruding portion 13c does not overlap with the electrode laminate 14 in the direction X, and is provided along the side surface 15c of the holding member 15. In the first embodiment, the entire base end portion 13d is in close contact with the side surface 15c of the corresponding holding member 15. In addition, the entire base end portion 13d of the outermost negative electrode current collector plate 13A is in close contact with the main surface 8a of the insulating buffer member 8. Each bent portion 13f is bent so as to be substantially at a right angle when viewed from the direction Y.

The tip portion 13e of the protruding portion 13c of the negative electrode current collector plate 13 excluding the outermost negative electrode current collector plate 13A overlaps the electrode laminate 14 and the connecting member 4 in the direction Z, and is along the outer peripheral surface 15b of the holding member 15. It is postponed. In the first embodiment, the entire tip portion 13e is in close contact with both the outer peripheral surface 15b of the holding member 15 and the connecting member 4. These tip portions 13e, the corresponding holding member 15, and the connecting member 4 overlap along the direction Z, and the holding member 15 and the tip portion 13e are welded on the third region R3 where they are in contact with each other. Part W3 is provided. The welded portion W3 is a portion for joining the negative electrode current collector plate 13 and the connecting member 4, and is provided at a portion where the tip portion 13e and the connecting member 4 are in contact with each other. The welded portion W3 is formed by, for example, laser welding. When the welded portion W3 is formed, the holding member 15 also functions as a pedestal in the welding process. The length of the tip portion 13e along the direction X is 10% or more and 90% or less of the length of the holding member 15 along the direction X. In this case, a region for forming the welded portion W3 can be secured at the tip portion 13e. In the first embodiment, the length of the tip portion 13e along the direction X is 40% of the length of the holding member 15 along the direction X. Since the tip portion 13e extends along the outer peripheral surface 15b of the holding member 15 as described above, the joining between the tip portion 13e and the connecting member 4 is also carried out outside the holding member 15.

The tip portion 13e of the protruding portion 13c of the outermost negative electrode current collector plate 13A extends along the direction X so as to be away from the storage cell 11. Therefore, the tip portion 13e overlaps with the insulating buffer member 8 in the direction Z and extends along the outer peripheral surface 8b of the insulating buffer member 8. In the first embodiment, the entire tip portion 13e is in close contact with both the outer peripheral surface 8b of the insulating buffer member 8 and the connecting member 4. A welded portion is formed on a fourth region R4 in which the tip portion 13e, the insulating buffer member 8, and the connecting member 4 overlap along the direction Z, and the insulating buffer member 8 and the tip portion 13e are in contact with each other. W4 is provided. The welded portion W4 is a portion that joins the outermost negative electrode current collector plate 13A and the connecting member 4. Like the welded portion W3, the welded portion W4 is formed by, for example, laser welding. When the welded portion W4 is formed, the insulating buffer member 8 also functions as a pedestal in the welding process. The length of the tip portion 13e of the outermost negative electrode current collector plate 13A along the direction X is 10% or more and 90% or less of the thickness of the insulating buffer member 8 along the direction X. In this case, a region for forming the welded portion W4 can be secured at the tip portion 13e. In the first embodiment, the length of the tip portion 13e of the outermost negative electrode current collector plate 13A along the direction X is 80% of the thickness of the insulating buffer member 8.

The tip portion 13e of the negative electrode current collector plate 13 excluding the outermost negative electrode current collector plate 13A and the tip portion 13e of the outermost negative electrode current collector plate 13A extend along the same direction. Specifically, the tip portion 13e extends toward the other side in the direction X. Therefore, the extending direction of the tip portion 12e of each positive electrode current collector plate 12 and the extending direction of the tip portion 13e of each negative electrode current collector plate 13 are opposite to each other.

FIG. 7 is a schematic cross-sectional view showing a usage example of the power storage device according to the first embodiment. As shown in FIG. 7, the power storage device 1 is placed in a vehicle 100 such as an automobile in a state of being housed in, for example, a battery pack 60. The battery pack 60 is a container for accommodating the cell stack 2 including a plurality of storage cells 11, and is fixed to the vehicle 100. In the first embodiment, the power storage device 1 is mounted on the lower part of the passenger compartment 110 provided with the front seat 101, the rear seat 102, and the like in the vehicle 100. That is, the power storage device 1 is housed under the floor of the passenger compartment 110. In the usage example shown in FIG. 7, the direction X corresponds to the front-rear direction of the vehicle 100, the direction Y corresponds to the width direction of the vehicle 100, and the direction Z corresponds to the height direction of the vehicle 100. The power storage device 1 is mounted in the lower part of the passenger compartment 110, but is not limited to this, and may be in the vehicle 100.

FIG. 8 is a schematic cross-sectional view of a main part of the power storage device shown in FIG. As shown in FIG. 8, the cell stack 2 of the power storage device 1 is housed in the battery pack 60 and is arranged on the bottom surface 61 of the battery pack 60. Therefore, each storage cell 11 included in the cell stack 2 is arranged on the bottom surface 61 of the battery pack 60. In the first embodiment, the holding member 15 of each storage cell 11 is in contact with the bottom surface 61. The extending portion 5b of the restraining member 5 extends along the direction X from one end of the main portion 5a located on the bottom surface 61 side in the direction Z. Specifically, each extending portion 5b extends away from the cell stack 2 in the direction X. The extending portion 5b is fixed to the bottom surface 61 by, for example, a fastening member or an adhesive. In the first embodiment, the restraint member 5 is separated from the side surface 62 of the battery pack 60, but the present invention is not limited to this.

The protrusion 12c extends away from the bottom surface 61 of the battery pack 60 in direction Z. Similarly, the protrusion 13c extends away from the bottom surface 61 of the battery pack 60 in direction Z (not shown). Therefore, the connecting members 3 and 4 are located on the side opposite to the bottom surface 61 with the power storage cell 11 in the direction Z. In other words, in direction Z, the cell stack 2 is located between the connecting member 3 (connecting member 4) and the bottom surface 61. Here, as shown in FIG. 1, the cover portion 9a of the cover member 9 is located between the connecting members 3 and 4. Therefore, each storage cell 11 included in the cell stack 2 is located between the cover portion 9a of the cover member 9 and the bottom surface 61.

According to the power storage device 1 according to the first embodiment described above, the welded portion W1 for joining the positive electrode current collector plate 12 and the connecting member 3 is connected to the holding member 15 and the protruding portion 12c of the positive electrode current collector plate 12. The members 3 are sequentially overlapped with each other, and the holding member 15 and the projecting portion 12c are provided on the first region R1 in contact with each other. Therefore, the holding member 15 included in the power storage cell 11 and holding the plurality of bipolar electrodes 16 can be used as a pedestal to form the welded portion W1. As a result, the process of preparing the jig for forming the welded portion W1 and the process of taking out the jig can be omitted. In addition, by using the holding member 15 that holds the plurality of bipolar electrodes 16 as a pedestal for forming the welded portion W1, it is possible to improve the productivity without increasing the number of parts of the power storage device 1. ..

Further, in the welded portion W3 for joining the negative electrode current collector plate 13 and the connecting member 4, the holding member 15, the protruding portion 13c of the negative electrode current collecting plate 13 and the connecting member 4 are sequentially overlapped with each other, and the holding member 15 and the protruding portion are overlapped with each other. It is provided on the third region R3 where the 13c and the 13c are in contact with each other. Therefore, similarly to the welded portion W1, the step of preparing the jig for forming the welded portion W3, the step of taking out the jig, and the like can be omitted. In addition, by using the holding member 15 as a pedestal for forming the welded portion W3, further improvement in productivity becomes possible.

The protruding portion 12c of the positive electrode current collector plate 12 includes a base end portion 12d extending along the direction Z, a tip portion 12e extending along the direction X and located outside the storage cell 11 in the direction Z, and a tip portion 12e. The holding member 15 has a bent portion 12f that connects the base end portion 12d and the tip end portion 12e, and the holding member 15 is located between the electrode laminate 14 and the tip end portion 12e in the direction Z, and is an outer peripheral surface that contacts the tip end portion 12e. It has 15b, and the welded portion W1 is provided at the tip portion 12e. Therefore, even when a plurality of storage cells 11 are arranged without gaps along the direction X, the welded portion W1 can be easily provided. In addition, the protruding portion 13c of the negative electrode current collector plate 13 also includes a base end portion 13d and a tip portion 13e, and the holding member 15 is located between the electrode laminate 14 and the tip portion 13e in the direction Z. It has an outer peripheral surface 15b that contacts the tip portion 13e, and the welded portion W3 is provided on the tip portion 13e. As a result, the welded portion W3 can be easily provided even when the plurality of storage cells 11 are arranged without gaps along the direction X.

The base end portion 12d is in close contact with the side surface 15c of the holding member 15 that intersects the direction X. Therefore, since the base end portion 12d is supported by the holding member 15, damage to the protruding portion 12c due to vibration or the like can be suppressed. In addition, the base end portion 13d of the negative electrode current collector plate 13 is also in close contact with the side surface 15c of the holding member 15 intersecting the direction X. Therefore, since the base end portion 13d is supported by the holding member 15, damage to the protruding portion 13c due to vibration or the like can be suppressed.

The electrode laminate 14 includes a plurality of bipolar electrodes 16. Therefore, the internal resistance of the storage cell 11 can be reduced.

The power storage device 1 includes a plurality of power storage cells 11 and a cell stack 2 having a plurality of current collector plates including a positive electrode current collector plate 12 and a negative electrode current collector plate 13. In the cell stack 2, a plurality of power storage cells 11 And a plurality of current collector plates are alternately arranged along the direction X. Therefore, since the number of current collector plates in the cell stack 2 can be reduced, the weight of the power storage device 1 can be reduced.

The holding member 15 is provided on the outer peripheral surface 14c of the electrode laminate 14. Therefore, the outer peripheral surface 14c of the electrode laminate 14 can be protected by the holding member 15.

The power storage device 1 includes a welded portion W2 that joins the outermost positive electrode current collector plate 12A adjacent to the power storage cell 11 located on the outermost side in the direction X, the outermost positive electrode current collector plate 12A, and the connecting member 3, and the direction X. The restraining members 5 and 6 for applying a binding force to the storage cell 11 and an insulating buffer member 7 arranged between the storage cell 11 and the restraining member 5 are provided along the above. In addition, the outermost positive electrode current collector plate 12A having the main body portion 12a and the protruding portion 12c like the positive electrode current collector plate 12 is arranged between the storage cell 11 and the insulating buffer member 7, and the welded portion W2 is formed. The insulating buffer member 7, the protruding portion 12c, and the connecting member 3 are sequentially overlapped with each other, and the insulating buffer member 7 and the protruding portion 12c are provided on the second region R2 in contact with each other. Therefore, the insulating buffer member 7 can be used as a pedestal when the welded portion W2 is formed. As a result, the process of preparing the jig for forming the welded portion W2, the process of taking out the jig, and the like can be omitted. Further, the protruding portion 12c of each positive electrode current collector plate 12 including the outermost positive electrode current collector plate 12A can be bent in the same direction.

Further, in the welded portion W4, the insulating buffer member 8, the protruding portion 13c of the outermost negative electrode current collector plate 13A, and the connecting member 4 are sequentially overlapped with each other, and the insulating buffer member 8 and the protruding portion 13c are in contact with each other. Since it is provided on the fourth region R4, the insulating buffer member 8 can be used as a pedestal when the welded portion W4 is formed. As a result, the process of preparing the jig for forming the welded portion W4, the process of taking out the jig, and the like can also be omitted.

The protrusion 12c of the outermost positive electrode current collector plate 12A includes a base end portion 12d extending along the direction Y, a tip end portion 12e extending along the direction X so as to be away from the storage cell 11, and a base end portion. The insulating buffer member 7 has a bent portion 12f connecting the 12d and the tip portion 12e, and the insulating buffer member 7 has a main surface 7a that intersects the direction X and contacts the main body portion 12a, and the main surface 7a along the direction X from the edge. It has an extending outer peripheral surface 7b, and the welded portion W2 is provided at the tip end portion 12e of the protruding portion 12c of the outermost positive electrode current collector plate 12A. Therefore, even when the storage cell 11, the outermost positive electrode current collector plate 12A, and the insulating buffer member 7 located on the outermost side in the direction X are arranged in order along the direction X without a gap. The welded portion W2 can be easily provided. In addition, the protruding portion 13c of the outermost negative electrode current collector plate 13A also includes a base end portion 13d and a tip portion 13e, and the welded portion W4 is provided at the tip portion 13e of the outermost negative electrode current collector plate 13A. As a result, the welded portion W4 can be easily provided as well as the welded portion W2.

The base end portion 12d of the protruding portion 12c of the outermost positive electrode current collector plate 12A is in close contact with the main surface 7a of the insulating buffer member 7. Therefore, since the base end portion 12d is supported by the insulating buffer member 7, damage to the protruding portion 12c of the outermost positive electrode current collector plate 12A due to vibration or the like can be suppressed. In addition, the base end portion 13d of the outermost negative electrode current collector plate 13A is also in close contact with the main surface 8a of the insulating buffer member 8. Therefore, since the base end portion 13d is supported by the insulating buffer member 8, damage to the protruding portion 13c of the outermost negative electrode current collector plate 13A due to vibration or the like can be suppressed.

Further, the power storage device 1 includes a battery pack 60 for accommodating the cell stack 2, each of the plurality of power storage cells 11 is erected along the direction Z, and each of the plurality of power storage cells 11 is erected along the direction Z. The dimension D1 is longer than both the dimension D3 along the direction X and the dimension D3 along the direction Z, and the area of the surface intersecting the direction Z in the cell stack 2 is included in the other cell stack 2. Larger than any of the faces. Therefore, the plurality of power storage cells 11 can be sandwiched between the restraint members 5 and 6 in a vertically placed state. As a result, the storage cells 11 are easily restrained from each other, so that the productivity can be further improved. In addition, since the restraint members 5 and 6 can be miniaturized, the power storage device 1 can be miniaturized. Further, the capacity of the power storage device 1 can be secured while suppressing the height of the battery pack 60. Further, the restraining force by the restraining members 5 and 6 is applied to the entire surface intersecting the direction X in the cell stack 2. Here, the area of the surface intersecting the direction X in the cell stack 2 is smaller than the area of the surface intersecting the direction Z in the cell stack 2. Therefore, when the binding force applied per unit area to the cell stack 2 is the same, the binding force applied by the restraint members 5 and 6 is constrained by the entire surface intersecting the direction Z in the cell stack 2. It can be less than the binding force applied when pinched by the member.

Each of the plurality of storage cells 11 is arranged on the bottom surface 61 of the battery pack 60. Therefore, a plurality of storage cells 11 can be stably arranged in the battery pack 60.

In the power storage device 1, the protrusions 12c and 13c are separated from each other. Therefore, even if both the protruding portions 12c and 13c are located on one side of the storage cell 11 in the direction Z, it is possible to prevent the protruding portions 12c and 13c from being short-circuited. Here, each of the dimension along the direction Y of the protruding portion 12c and the dimension along the direction Y of the protruding portion 13c is less than half of the dimension D1 of the power storage cell 11. Therefore, it is possible to more reliably prevent the protruding portions 12c and 13c from being short-circuited.

Each of the connecting members 3 and 4 is located on one side in the direction Z of the storage cell 11. Therefore, the welding of the connecting member 3 to the protruding portion 12c and the welding of the connecting member 4 to the protruding portion 13c can be performed in one step, so that the productivity can be further improved.

Each of the main bodies 12a and 13a overlaps the storage cell 11 in the direction X and does not overlap the holding member 15. Therefore, the load applied from the restraint members 5 and 6 to the electrode laminate 14 of the storage cell 11 along the direction X is satisfactorily applied from the main body portions 12a and 13a to the holding member 15 without being dispersed.

Each of the restraint members 5 and 6 has a main portion 5a that applies a load to the plurality of storage cells 11 along the direction X, and one end of the main portion 5a located on the bottom surface 61 side of the battery pack 60 in the direction X. It has an extending portion 5b extending along the line, and the extending portion 5b is fixed to the bottom surface 61 of the battery pack 60. Therefore, since the restraint members 5 and 6 in the battery pack 60 can be positioned, a plurality of storage cells 11 can be stably arranged in the battery pack 60.

The power storage device 1 includes a cover member 9 that regulates the movement of the plurality of power storage cells 11 in the direction Z, and the cover member 9 and at least one of the restraint members 5 and 6 may be integrated. In this case, the number of fastening members E for fastening the cover member 9 to any of the restraint members 5 and 6 can be reduced.

In the direction Z, the plurality of storage cells 11 may be located between the cover member 9 and the bottom surface 61 of the battery pack 60. In this case, even if the shape of the cover member 9 does not surround the plurality of power storage cells 11, the position of the power storage cells 11 is satisfactorily determined in the battery pack 60.

Next, a modified example of the first embodiment will be described with reference to FIGS. 9A and 9B. FIG. 9A is a schematic cross-sectional view of a main part showing the power storage device of the first modification of the first embodiment, and FIG. 9B shows the power storage device of the second modification of the first embodiment. It is a schematic cross-sectional view of a main part.

As shown in FIG. 9A, the holding member 15A of the power storage cell 11A in the first modification has a thin-walled portion 31 and a thick-walled portion 32 thicker than the thin-walled portion 31. The thin-walled portion 31 is a holding portion that contacts the outer peripheral surface 14c of the electrode laminate 14 and holds a plurality of bipolar electrodes 16. The thin-walled portion 31 can also function as a sealing member having a substantially rectangular frame shape so as to seal the outer peripheral surface 14c, and a short-circuit prevention member for preventing short-circuiting between the bipolar electrodes 16 in the electrode laminate 14. The thin-walled portion 31 contains, for example, various resin materials. The resin member is, for example, polyimide, PP, PPS, PA66 or the like. The thickness of the thin portion 31 is, for example, 1 mm or more and 5 mm or less. In this case, the plurality of bipolar electrodes 16 can be held satisfactorily. The thickness of the thin portion 31 corresponds to the distance from the inner peripheral surface 15a along the direction Y or the direction Z to the thick portion 32.

The thick portion 32 is a portion that functions as a pedestal for the welded portion W1. The thick portion 32 is provided so as to overlap at least the first region R1 (see FIGS. 5 (a) and 5 (b)) and the third region R3 (see FIGS. 6 (a) and 6 (b)). That is, the thick portion 32 is provided at least between the thin portion 31 and the connecting member 3 and between the thin portion 31 and the connecting member 4 in the direction Z. FIG. 9A discloses an embodiment in which the thick portion 32 is provided only between the thin portion 31 and the connecting member 3 in the direction Z. The thick portion 32 has a heat-resistant portion 33 that is in close contact with a part of the thin portion 31 that is a holding portion. The outer peripheral surface of the heat-resistant portion 33 comes into contact with the tip portion 12e of the positive electrode current collector plate 12. The heat-resistant portion 33 is, for example, a resin material exhibiting heat resistance. The thickness of the heat-resistant portion 33 is, for example, 1 mm or more and 5 mm or less. In this case, the heat-resistant portion 33 suppresses damage to the thin-walled portion 31 and the electrode laminate 14 due to heat generated when the welded portion W1 is formed. Although not shown, the heat-resistant portion 33 is also in contact with the tip portion 13e of the negative electrode current collector plate 13, so that the thin-walled portion 31 and the electrode laminate 14 are damaged due to the heat generated during the formation of the welded portion W3. Etc. are also suppressed by the heat-resistant portion 33.

According to the first modification described above, in addition to the effects exerted by the power storage device 1 of the first embodiment, the weight reduction of the power storage device 1 can be realized. Further, when the welded portion W1 is formed, it is possible to prevent the portion of the holding member 15A that overlaps the welded portion W1 from being damaged. As a result, it is possible to satisfactorily suppress the occurrence of initial defects of the power storage device 1 due to the formation of the welded portion W1.

In the first modification, the thin-walled portion 31 and the thick-walled portion 32 are formed of different resin materials, but the present invention is not limited to this. The thin-walled portion 31 and the thick-walled portion 32 may be made of a resin material exhibiting the same heat resistance as each other. In this case, the thin-walled portion 31 and the thick-walled portion 32 are integrated with each other and are formed at the same time. In this case, the thick portion of the holding member 15A corresponds to the thick portion 32, and the portion of the holding member 15A other than the thick portion 32 corresponds to the thin portion 31.

Further, in FIG. 9A, the thick portion 32 is provided only between the thin portion 31 and the connecting member 3 in the direction Z, but is not limited to this. For example, the thick portion 32 is on one side of the electrode laminate 14 in the direction Z (upper side of the paper surface than the electrode laminate 14 in FIG. 9A) and on the other side of the electrode laminate 14 along the direction Z. (In FIG. 9A, the lower side of the paper surface than the electrode laminate 14) may be provided. In this case, the thickness of the holding member 15A on one side of the electrode laminate 14 along the direction Z and the thickness of the holding member 15A on the other side of the electrode laminate 14 along the direction Z are the same.

As shown in FIG. 9B, the heat-resistant portion 33A of the thick portion 32A of the holding member 15B may be a rectangular plate-shaped member exhibiting heat resistance. The heat-resistant portion 33A is provided between the thin-walled portion 31 and the connecting member 3 in the direction Z, for example. The heat-resistant portion 33A overlaps only a part of the thin-walled portion 31, and includes, for example, an inorganic material exhibiting heat resistance. Examples of the inorganic material exhibiting heat resistance include ceramics such as alumina. Even when the holding member 15B having such a heat-resistant portion 33A is used, the same action and effect as those of the first modification can be obtained.

(Second Embodiment)
Hereinafter, the power storage device according to the second embodiment will be described. In the description of the second embodiment, the description overlapping with the first embodiment will be omitted, and the part different from the first embodiment will be described. That is, the description of the first embodiment may be appropriately used for the second embodiment to the extent technically possible.

The cell stack of the second embodiment includes two types of positive electrode current collector plates and two types of negative electrode current collector plates. In the following, two types of positive electrode current collector plates and two types of negative electrode current collector plates will be described with reference to FIGS. 10 and 11. Further, in the following, the storage cell in which the first type positive electrode current collector plate and the negative electrode current collector plate are adjacent to each other is referred to as the first storage cell 41a, and the storage cell in which the second type positive electrode current collector plate and the negative electrode current collector plate are adjacent to each other is referred to as the first storage cell. 2 The storage cell 41b.

FIG. 10A is a schematic perspective view of the first storage cell and the current collector plate in contact with the first storage cell, and FIG. 10B is a schematic perspective view of the first storage cell and the first storage cell in contact with the first storage cell. It is a schematic side view of a current collector plate. As shown in FIGS. 10A and 10B, the protruding portion 44 of the positive electrode current collector plate 42 in contact with the first storage cell 41a is the side surface 15c and the outer peripheral surface 15b of the holding member 15 in the first storage cell 41a. It is bent along. Therefore, the protruding portion 44 has a base end portion 44a, a tip portion 44b in contact with the outer peripheral surface 15b, and a bent portion 44c. In the second embodiment, the entire tip portion 44b is in contact with the outer peripheral surface 15b. The protruding portion 45 of the negative electrode current collector plate 43 that contacts the first storage cell 41a is also bent along the side surface 15c and the outer peripheral surface 15b. Therefore, the protruding portion 45 has a base end portion 45a, a tip portion 45b in contact with the outer peripheral surface 15b, and a bent portion 45c. In the second embodiment, the entire tip portion 45b is in contact with the outer peripheral surface 15b.

FIG. 11A is a schematic perspective view of the second storage cell and the current collector plate in contact with the second storage cell, and FIG. 11B is a schematic perspective view of the second storage cell and the second storage cell in contact with the second storage cell. It is a schematic side view of a current collector plate. As shown in FIGS. 11A and 11B, the tip of the protruding portion 48 of the positive electrode current collector plate 46 in contact with the second storage cell 41b is separated from the electrode laminate 14 of the second storage cell 41b. It is folded into. Therefore, the protruding portion 48 has a base end portion 48a, a tip portion 48b extending along the direction X so as to be separated from the electrode laminate 14, and a bent portion 48c. The tip portion 48b does not overlap the electrode laminate 14 in the direction Z, and does not contact the outer peripheral surface 15b of the holding member 15 in the second storage cell 41b. The bent portion 48c is provided at a position farther from the electrode laminate 14 than the bent portion 45c in the direction Z. For example, the bent portion 48c is provided at a position separated from the electrode laminate 14 by the thickness of the positive electrode current collector plate 46 with respect to the bent portion 45c in the direction Z.

The protruding portion 49 of the negative electrode current collector plate 47 is also bent so that its tip is separated from the electrode laminate 14 in the second storage cell 41b. Therefore, the protruding portion 49 has a base end portion 49a, a tip portion 49b extending along the direction X so as to be separated from the electrode laminate 14, and a bent portion 49c. The tip portion 49b does not overlap with the electrode laminate 14 in the direction Z, and does not touch the outer peripheral surface 15b of the holding member 15 in the second storage cell 41b. The bent portion 49c is provided at a position farther from the electrode laminate 14 than the bent portion 45c in the direction Z. For example, the bent portion 49c is provided at a position separated from the electrode laminate 14 by the thickness of the negative electrode current collector plate 47 with respect to the bent portion 45c in the direction Z.

FIG. 12 is a schematic cross-sectional view of a main part showing the power storage device of the second embodiment. In the power storage device 1A shown in FIG. 12, the first power storage cells 41a and the second power storage cells 41b are alternately arranged along the direction X. Further, in the second embodiment, the first storage cell 41a and the second storage cell 41b are connected to each other in parallel. Therefore, the positive electrode current collector plates 42 and 46 are in contact with each other, and the negative electrode current collector plates 43 and 47 are in contact with each other. Further, the protruding portion 45 of the positive electrode current collecting plate 42 in the first storage cell 41a is covered with the protruding portion 48 of the positive electrode current collecting plate 46 in the second storage cell 41b. Although not shown, the protruding portion 45 of the negative electrode current collecting plate 43 is covered with the protruding portion 49 of the negative electrode current collecting plate 47. In the second embodiment, the welded portion W1A joins the connecting member 3 and the protruding portions 44 and 48. Specifically, the welded portion W1A joins the connecting member 3, the tip portion 44b of the protrusion 44, and the tip 48b of the protrusion 48.

The power storage device 1A according to the second embodiment described above also has the same effects as those of the first embodiment.

(Third Embodiment)
Hereinafter, the power storage device according to the third embodiment will be described. In the description of the third embodiment, the description overlapping with the first embodiment and the second embodiment will be omitted, and the parts different from the first embodiment and the second embodiment will be described. That is, the description of the first embodiment and the second embodiment may be appropriately used for the third embodiment to the extent technically possible.

FIG. 13 is a schematic cross-sectional view of a main part showing the power storage device of the third embodiment. The positive electrode current collector plate 52 and the negative electrode current collector plate 53 included in the power storage device 1B shown in FIG. 13 are conductive members having a substantially L-shaped plate shape with each other. The positive electrode current collector plate 52 has a main body portion 54 in contact with the electrode laminate 14 of the power storage cell 11 and a protruding portion 55 projecting from one end of the main body portion 54 along the direction Z, and the negative electrode current collector plate 53 has a negative electrode current collector plate 53. It has a main body 56 that comes into contact with the electrode laminate 14 of the power storage cell 11, and a protruding portion 57 that protrudes from one end of the main body 56 along the direction Z. The projecting portions 55 and 57 project toward opposite sides in the direction Z. Therefore, the protruding portion 55 protrudes toward one side in the direction Z (upper side of the paper surface in FIG. 13), and the protruding portion 57 protrudes toward the other side in the direction Z (lower side of the paper surface in FIG. 13). There is.

The power storage device 1B includes connection members 3A and 4A having a substantially rectangular plate shape, and the connection members 3A and 4A sandwich the power storage cells 11 in the direction Z. The connecting member 3A is located on one side in the direction Z from each storage cell 11 (upper side of the paper in FIG. 13), and the connecting member 4A is located on the other side in the direction Z from each storage cell 11 (in FIG. 13). Is located on the lower side of the page). The connecting member 3A is joined to the tip portion 55b of the protruding portion 55 of the positive electrode current collector plate 52 via the welded portion W1, and the connecting member 4A is joined to the protruding portion 57 of the negative electrode current collector plate 53 via the welded portion W3. It is joined to the tip portion 57b of.

The extending direction of the tip portion 55b of the positive electrode current collector plate 52 located on the outermost side of the power storage device 1B and the extending direction of the tip portion 55b of the other positive electrode current collector plate 52 are opposite to each other. As a result, even if the length of the tip portion 55b of the positive electrode current collector plate 52 located on the outermost side along the direction X is longer than the thickness of the insulating buffer member 7, the tip portion 55b becomes the restraint member 5. It is possible to prevent contact. Further, the extending direction of the tip portion 57b of the negative electrode current collector plate 53 located on the outermost side of the power storage device 1B and the extending direction of the tip portion 57b of the other negative electrode current collector plate 53 are opposite to each other. .. As a result, even if the length of the tip portion 57b of the negative electrode current collector plate 53 located on the outermost side along the direction X is longer than the thickness of the insulating buffer member 8, the tip portion 57b becomes the restraint member 6. It is possible to prevent contact.

The power storage device 1B according to the third embodiment described above also has the same effects as those of the first embodiment.

The power storage device according to the present invention is not limited to the above-described embodiment and the above-mentioned modification, and various other modifications are possible. For example, in the above-described embodiment and the above-described modified example, the power storage cell has a substantially rectangular shape when viewed from the direction X, but the present invention is not limited to this. The power storage cell may have a polygonal shape such as a triangular shape or a pentagonal shape when viewed from the direction X, may have a circular shape, or may have an elliptical shape. Similarly, the shape of each current collector plate or the like is not limited to the above-described embodiment and the above-mentioned modification. Further, in the above-described embodiment and the above-described modified example, the power storage cell is vertically arranged, but the present invention is not limited to this. Each storage cell may be placed horizontally. In this case, the shape of the restraint member may be changed as appropriate.

In the above-described embodiment and the above-described modification, each of the positive electrode current collector plate and the negative electrode current collector plate is subjected to bending processing or the like before being arranged in the cell stack, but the present invention is not limited to this. For example, when each of the positive electrode current collector plate and the negative electrode current collector plate is molded, the base end portion, the tip end portion, and the bent portion may be provided in advance. In this case, bending processing for each of the protruding portions of the positive electrode current collector plate and the negative electrode current collector plate can be omitted.

In the above-described embodiment and the above-described modified example, the edge of the positive electrode main body portion does not overlap the holding member when viewed from the direction X, but the present invention is not limited to this. The edge may be located inside the outer peripheral surface of the holding member. As long as the edge is located inside the outer peripheral surface of the holding member, at least a part of the edge may overlap the holding member when viewed from the direction X. Specifically, the edge may overlap the inner peripheral surface of the holding member or may be located on the side surface of the holding member. Further, for example, the total value of the dimension D12 of the positive electrode body and the length of the proximal end along the direction Z is less than the dimension D2 of the power storage cell (that is, D2> D12 + the length of the proximal end along the direction Z). It may be. In this case, assuming that the edge of the positive electrode body includes a first edge that intersects the direction Z and is connected to the positive electrode protrusion, and a second edge that is located on the opposite side of the first edge in the direction Z, at least. The second edge portion is located inside the outer peripheral surface of the holding member. As a result, when the power storage device is housed in the case, the second edge portion and the bottom surface of the case are separated from each other in the direction Z. Therefore, the positive electrode main body portion is less likely to be short-circuited to the case or the like via the second edge portion. Similarly, the edge of the negative electrode main body may be located inside the outer peripheral surface of the holding member. The edge of the negative electrode body has a third edge that intersects the direction Z and is connected to the protruding negative electrode, and a fourth edge that is located on the opposite side of the third edge in the direction Z, and is at least the fourth edge. May be located inside the outer peripheral surface of the holding member. As a result, the negative electrode main body portion is less likely to be short-circuited to the case or the like via the fourth edge portion.

In the above embodiment and the above modification, the electrode laminate includes a bipolar electrode, but the electrode laminate is not limited to this. For example, the electrode laminate may include a positive electrode foil provided with a positive electrode layer, a negative electrode foil provided with a negative electrode layer, and a separator.

In the above-described embodiment and the above-described modification, the holding member has a substantially rectangular frame shape so as to seal the outer peripheral surface of the electrode laminate, but is not limited to this. For example, when the electrolyte is a solid electrolyte and the separator is composed of the solid electrolyte, a part of the outer peripheral surface of the electrode laminate may be exposed from the holding member. For example, the holding member may be located between the storage cell and the tip of the current collector plate in contact with the storage cell in the direction Z, and may be in contact with the tip. Even in this case, since the tip portion is in contact with the outer peripheral surface of the holding member, the holding member functions as a pedestal when forming the welded portion. On the other hand, when the electrolyte exhibits fluidity, it is preferable that the holding member seals the entire outer peripheral surface of the electrode laminate. As a result, the occurrence of a short circuit via the electrolyte can be satisfactorily suppressed by the holding member.

In the above embodiment, the holding member has a substantially rectangular frame shape, but the present invention is not limited to this. The holding member may be, for example, a pair of cover members separated from each other. When the holding member is a pair of cover members and the cell stack is housed in the battery pack, one cover member is located between the battery laminate and the bottom surface of the battery pack. Further, in the above embodiment, the thickness of the holding member is substantially constant, but the thickness is not limited to this. For example, when the cell stack is housed in the battery pack, the thickness of the portion of the holding member located between the electrode laminate and the bottom surface of the battery pack may be the largest. When the electrode laminate contains a bipolar electrode, the thickness of the portion of the holding member between the bipolar electrode and the bottom surface may be the largest. As a result, it is possible to suppress the occurrence of a short circuit between the power storage device and the bottom surface of the battery pack or the liquid collected on the bottom surface. In addition, it is possible to prevent the positive electrode current collector and the negative electrode current collector in the cell stack from being short-circuited via the bottom surface of the battery pack or the like.

In the above-described embodiment and the above-described modification, the bent portions of the positive electrode current collector plate and the negative electrode current collector plate are bent at substantially right angles, but the present invention is not limited to this. For example, the bent portion may have a curved shape. In this case, the bent portion in the protruding portion and its vicinity (that is, a part of the base end portion and a part of the tip end portion) may be separated from the holding member or the like. That is, a gap may be formed between the bent portion and its vicinity and the protective member or the like.

In the above embodiment and the above modification, the storage cells in the cell stack are connected in parallel, but the present invention is not limited to this. For example, the storage cells may be connected in series. In this case, one connecting member that functions as a positive electrode of the power storage device may be connected to one of a plurality of power storage cells included in the cell stack. Further, the other connecting member that functions as the negative electrode of the power storage device may be connected to a power storage cell different from the one power storage cell described above.

In the above embodiment and the above modification, the power storage cell, the positive electrode current collector plate, and the negative electrode current collector plate are separate from each other, but the present invention is not limited to this. For example, the storage cell, the positive electrode current collector plate, and the negative electrode current collector plate may be integrated with each other. In this case, for example, the holding member may integrate the electrode laminate, the positive electrode current collector plate, and the negative electrode current collector plate. As a result, contact between the electrode laminate and the positive electrode current collector plate and the negative electrode current collector plate can be ensured. Further, the cell stack includes both a unit in which the current collector cell, the positive electrode current collector plate and the negative electrode current collector plate are integrated with each other, and a storage cell in which the positive electrode current collector plate and the negative electrode current collector plate are separate bodies. You may. In this case, the unit and the storage cell are alternately arranged along the direction X.

In the above-described embodiment and the above-described modification, the welded portion is provided on the first region where the holding member, the protruding portion of the positive electrode current collector plate, and the connecting member overlap along the direction Z, but the welding portion is limited to this. No. For example, the welded portion may be provided on the first region where the holding member, the protruding portion of the positive electrode current collector plate, and the connecting member overlap along the direction X or the direction Y. Similarly, a welded portion may be provided on a second region where the insulating buffer member, the protruding portion of the outermost positive electrode current collector plate, and the connecting member overlap along the direction X or the direction Y. Further, a welded portion may be provided on a third region where the holding member, the protruding portion of the negative electrode current collector plate, and the connecting member overlap along the direction X or the direction Y, and the insulating buffer member and the outermost portion may be provided. A welded portion may be provided on a fourth region where the protruding portion of the negative electrode current collector plate and the connecting member overlap along the direction X or the direction Y.

The above-described embodiment and the above-described modification may be combined as appropriate. For example, the second embodiment and the first modification may be combined with each other. Further, the first embodiment and the third embodiment may be combined with each other. For example, in the first embodiment, the extending direction of the tip of the outermost positive electrode current collector plate may be opposite to the extending direction of the tip of the other positive electrode current collector, or the outermost negative electrode current collector. The extending direction of the tip of the electric plate may be opposite to the extending direction of the tip of the other negative electrode current collector.

1,1A, 1B ... Power storage device, 2 ... Cell stack, 3, 3A ... Connection member (first connection member), 4,4A ... Connection member (second connection member), 5, 6 ... Restraint member, 7, 8 ... Insulation buffer member, 7a ... Main surface, 7b ... Outer surface, 9 ... Cover member, 11, 11A ... Storage cell, 12 ... Positive electrode current collector, 12a ... Main body, 12b ... Edge, 12c ... Projection, 12d ... Base end portion (first base end portion, second base end portion), 12e ... Tip portion (first tip portion, second tip portion), 12f ... Bending portion (first bending portion, second bending portion), 12A ... 14 ... Electrode laminate, 14a, 14b ... Main surface, 14c ... Outer surface, 15, 15A, 15B ... Holding member, 15a ... Inner peripheral surface, 15b ... Outer surface, 15c ... Side surface, 16 ... Bipolar electrode, 17 ... Separator , 21 ... Current collector, 22 ... Positive electrode layer, 23 ... Negative electrode layer, 31 ... Thin-walled part, 32, 32A ... Thick-walled part, 33, 33A ... Heat-resistant part, 41a ... First storage cell, 41b ... Second storage cell , 42, 46, 52 ... Positive electrode current collector, 43, 47, 53 ... Negative electrode current collector, D1 to D3, D11, D12 ... Dimensions, R1 ... 1st region, R2 ... 2nd region, W1, W1A ... Welding Parts (first welded part), W2 ... Welded parts (second welded part).

Claims (23)

A first electrode laminate including a plurality of first electrodes laminated along the first direction, and a first storage cell having a holding member for holding the plurality of first electrodes.
A first current collector plate adjacent to the first storage cell along the first direction,
A connecting member electrically connected to the first storage cell via the first current collector plate, and
A first welded portion that joins the first current collector plate and the connecting member,
With
The first current collector plate has a first main body portion that contacts the first electrode laminate and a first main body portion that protrudes from the edge of the first main body portion along a second direction that intersects the first direction. And have
The first welded portion is provided on a first region in which the holding member, the first protruding portion, and the connecting member are sequentially overlapped, and the holding member and the first protruding portion are in contact with each other.
Power storage device. The first protruding portion extends along the first base end portion extending along the second direction, extends along the first direction, and is located outside the first storage cell in the second direction. It has a first tip portion and a first bent portion that connects the first base end portion and the first tip portion.
The holding member is located between the first electrode laminate and the first tip portion in the second direction, and has an outer peripheral surface that contacts the first tip portion.
The power storage device according to claim 1, wherein the first welded portion is provided at the first tip portion. The power storage device according to claim 2, wherein the first base end portion is in close contact with a side surface of the holding member intersecting in the first direction. The power storage device according to any one of claims 1 to 3, wherein each of the plurality of first electrodes is a bipolar electrode. A plurality of current collector cells including the first current collector cell and a cell stack having a plurality of current collector plates including the first current collector plate are further provided.
The power storage device according to any one of claims 1 to 4, wherein the plurality of power storage cells and the plurality of current collector plates are alternately arranged along the first direction in the cell stack. The power storage device according to any one of claims 1 to 5, wherein the holding member is provided on the outer peripheral surface of the first electrode laminate. The power storage device according to claim 6, wherein the holding member seals the entire outer peripheral surface of the first electrode laminate. The holding member has a thin-walled portion and a thick-walled portion thicker than the thin-walled portion.
The power storage device according to any one of claims 1 to 7, wherein the thick portion overlaps at least the first region and comes into contact with the first protruding portion. The thin-walled portion is a holding portion that holds the plurality of first electrodes.
The power storage device according to claim 8, wherein the thick portion has a heat-resistant portion that is in close contact with a part of the holding portion. A second storage cell having a second electrode laminate including a plurality of second electrodes stacked along the first direction and arranged along the first storage cell together with the first storage cell, and a second storage cell.
A second current collector plate adjacent to the second storage cell along the first direction,
A second welded portion that joins the second current collector plate and the connecting member,
A restraining member that applies a binding force to the first storage cell and the second storage cell along the first direction, and
An insulating buffer member arranged between the second storage cell and the restraint member,
With more
The second current collector plate has a second main body portion that comes into contact with the second electrode laminate, and a second main body portion that protrudes from the edge of the second main body portion along the second direction.
The second main body is arranged between the second electrode laminate and the insulating buffer member.
The second welded portion is provided on a second region in which the insulating buffer member, the second protruding portion, and the connecting member are sequentially overlapped, and the insulating buffer member and the second protruding portion are in contact with each other. , The power storage device according to any one of claims 1 to 9. The second protruding portion includes a second base end portion extending along the second direction, a second tip portion extending along the first direction so as to be separated from the second storage cell, and the said portion. It has a second bent portion that connects the second base end portion and the second tip end portion.
The insulating buffer member has a main surface that intersects the first direction and contacts the second main body portion, extends from the edge of the main surface along the first direction, and contacts the second tip portion. Has an outer peripheral surface to
The power storage device according to claim 10, wherein the second welded portion is provided at the second tip portion. The power storage device according to claim 11, wherein the second base end portion is in close contact with the main surface of the insulating buffer member. A cell stack having a plurality of storage cells arranged along the first direction in the horizontal direction,
A pair of restraint members that sandwich the plurality of storage cells along the first direction, and
A battery pack accommodating the plurality of storage cells and
With
Each of the plurality of storage cells
Standing along the second direction that intersects in the horizontal direction,
It has a plurality of bipolar electrodes laminated along the first direction and a holding member for holding the plurality of bipolar electrodes.
In each of the plurality of storage cells, the dimension along the third direction intersecting the first direction in the horizontal direction is either the dimension along the first direction or the dimension along the second direction. Longer than
The area of the surface intersecting the second direction in the cell stack is much larger than any other surface that is included in the cell stack,
In each of the plurality of storage cells, a current collector corresponding to a positive electrode terminal is provided at one end in the first direction, and a current collector corresponding to a negative electrode terminal is provided at the other end in the first direction.
Power storage device. The power storage device according to claim 13, wherein each of the plurality of power storage cells is arranged on the bottom surface of the battery pack. The power storage device according to claim 14, wherein a portion of the holding member located between the bipolar electrode and the bottom surface of the battery pack has the largest thickness. The cell stack has a positive electrode current collector plate and a negative electrode current collector plate.
The positive electrode current collector plate includes a positive electrode body portion in contact with the current collector corresponding to the positive terminal of the first power storage cell included in the plurality of storage cells, and the positive electrode body portion along said second direction It has a positive electrode protrusion that protrudes from the edge, and has a positive electrode protrusion.
The negative electrode current collector plate, the said anode body portion in contact with the current collector corresponding to the negative terminal, and the negative electrode protrusion protruding from an edge of the negative electrode main body portion along the second direction of the first storage cells Have,
The power storage device according to any one of claims 13 to 15, wherein the positive electrode protruding portion and the negative electrode protruding portion are separated from each other in the third direction. The dimension of the positive electrode protrusion along the third direction and the dimension of the negative electrode protrusion along the third direction are half of the dimension of the first storage cell along the third direction. The power storage device according to claim 16, which is less than. A first connecting member welded to the positive electrode protrusion in the second direction,
A second connecting member welded to the negative electrode protrusion in the second direction is further provided.
The power storage device according to claim 16 or 17, wherein each of the first connection member and the second connection member is located on one side of the first power storage cell in the second direction. The edge of the positive electrode body includes a first edge that intersects the second direction and is connected to the positive electrode protrusion, and a second edge that is located on the opposite side of the first edge in the second direction. Have and
The edge of the negative electrode body has a third edge that intersects the second direction and is connected to the protruding negative electrode, and a fourth edge that is located on the opposite side of the third edge in the second direction. Have and
The power storage device according to any one of claims 16 to 18, wherein each of the second edge portion and the fourth edge portion is located inside the outer peripheral surface of the holding member. 16. Power storage device. Each of the pair of restraint members
A main part that applies a load to the plurality of storage cells along the first direction, and
It has an extending portion extending along the first direction from one end of the main portion located on the bottom surface side of the battery pack.
The power storage device according to any one of claims 13 to 20, wherein the extending portion is fixed to the bottom surface of the battery pack. A cover member for restricting the movement of the plurality of storage cells in the second direction is further provided.
The power storage device according to claim 21, wherein the cover member and at least one of the pair of restraint members are integrated. 22. The power storage device according to claim 22, wherein in the second direction, the plurality of power storage cells are located between the cover member and the bottom surface of the battery pack.

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