Power storage device

Abstract

To provide a power storage device capable of improving a vibration resistance or an impact resistance.SOLUTION: A power storage device includes: a first element unit 31 that includes a first element group 41 in which first power storage elements 51A and 51B are arranged in a first direction, and a first internal side member 42 that binds the first element group in the first direction of the first element group; and a second internal side member 102 that binds a second element group 101 in which second power storage elements 105A and 105B are arranged in the first direction and a second element group that is separately provided from the first inner side member, and binds the second element group in the first direction in the second element group. The power storage device comprises: a second element unit 32 that is arranged so as to be adjacent to the first element unit in the second direction crossed to the first direction; and an external member 33 that integrally binds the first element unit and the second element unit from an external side of the first and second inner side members.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a power storage device.

Background Art

[0002] Patent Document 1 discloses a power storage module in which a first unit in which a plurality of first power storage elements are stacked and a second unit in which a plurality of second power storage elements are stacked are attached on a heat transfer member, and the heat transfer member is further covered with a lid member. The first unit is fixed to the heat transfer member by a first fixing member, and the second unit is fixed to the heat transfer member by a second fixing member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration according to Patent Document 1 described above, the first unit and the second unit are each independently fixed. Therefore, on the heat transfer member, the first unit and the second unit may each move, and there is a possibility that the vibration resistance or shock resistance cannot be improved.

[0005] The present invention has been made by the inventors of the present application newly paying attention to the above problems, and an object thereof is to provide a power storage device capable of improving vibration resistance or shock resistance.

Means for Solving the Problems

[0006] To solve the above problems, a power storage device according to an aspect of the present invention includes a first element unit having a first element group in which first power storage elements are arranged in a first direction, and a first inner member that constrains the first element group in the first direction of the first element group; a second element group in which second power storage elements are arranged in the first direction, and a second inner member that is provided separately from the first inner member and that constrains the second element group in the first direction of the second element group, and a second element unit that is arranged adjacent to the first element unit in a second direction intersecting the first direction; and an outer member that collectively constrains the first element unit and the second element unit from the outside of the first inner member and the second inner member.

Advantages of the Invention

[0007] According to the above aspect, it is possible to improve vibration resistance or shock resistance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] (1) A power storage device according to one aspect of the present invention includes a first element unit having a first element group in which first power storage elements are arranged in a first direction and a first inner member that restrains the first element group in the first direction, a second element group in which second power storage elements are arranged in the first direction, and a second inner member that is provided separately from the first inner member and restrains the second element group in the first direction, and is disposed adjacent to the first element unit in a second direction intersecting the first direction. The second element unit, and an outer member that collectively restrains the first element unit and the second element unit from the outside of the first inner member and the second inner member.

[0010] According to this aspect, by arranging a plurality of power storage elements in a plurality of rows in the second direction, it is possible to reduce the size of each element unit in the first direction as compared with the case where the power storage elements are arranged in a single row in the first direction. Furthermore, by restraining the displacement of each element group in the first direction with the inner member, the expansion of each power storage element can be suppressed, and the characteristics of each power storage element can be maintained over a long period of time. In particular, by restraining each element group with a separate inner member, it is easy to restrain each element group while applying a desired pressure in the first direction to each element group. In addition, by collectively restraining each element unit with the outer member, the relative displacement of each element unit can be regulated. As a result, it is possible to improve the vibration resistance or shock resistance as compared with a configuration in which the first unit and the second unit are simply fixed independently as in the prior art. Therefore, the power storage device according to this aspect can provide a highly reliable power storage device over a long period of time while reducing the size in the first direction.

[0011] (2) In the power storage device according to the aspect of (1) above, the outer member may include a first outer plate disposed across only a portion facing the first side in the first direction among the first inner member and the second inner member, and a second outer plate disposed across only a portion facing the second side in the first direction among the first inner member and the second inner member. According to this aspect, each outer plate can restrain the relative displacement of each element unit in the second direction, thereby improving the vibration resistance or shock resistance. Further, since the outer member is disposed only at the portion facing the first direction with respect to the element unit, the size reduction of the power storage device in the second direction can be achieved as compared with the configuration in which the outer member surrounds the periphery of the element unit.

[0012] (3) In the power storage device according to the aspect of (2) above, the first outer plate may be joined to the first inner member and the second inner member by a first outer welding portion extending in a third direction intersecting the second direction when viewed from the first direction, and the second outer plate may be joined to the first inner member and the second inner member by a second outer welding portion extending in the third direction. According to this aspect, since each welding portion extends in a direction (third direction) intersecting the arrangement direction (second direction) of each element unit, it is difficult for each welding portion to straddle between each element unit. Therefore, the first inner member, the second inner member, and the outer member can be stably joined together. Further, since the inner member and the outer member are joined by welding, unlike a configuration in which the inner member and the outer member are fastened by screws or the like, there is no need to provide a fixing space (such as a flange portion) between the inner member and the outer member. Therefore, the size reduction of the power storage module becomes possible, and a small-sized power storage device can be provided.

[0013] (4) In the power storage device according to any one of the aspects (1) to (3) above, a case in which the first element unit and the second element unit are accommodated in a state of being restrained by the outer member is provided, and an engaging portion that engages with a positioning portion formed in the case may be formed on the outer member. According to this aspect, when the power storage module is formed by restraining each element unit by the outer member, the assembling efficiency when assembling the power storage module into the case can be improved. Further, by forming the engaging portion on the outer member itself, the cost can be reduced as compared with the case where a separate member is provided for positioning the power storage module and the case.

[0014] (5) In the power storage device according to any one of the aspects (1) to (4) above, the first inner member includes a first end portion disposed on the first side in the first direction with respect to the first element group, and a first side portion extending from both end portions in the second direction at the first end portion to the second side in the first direction. A first restraint plate having, a second end portion disposed on the second side in the first direction with respect to the first element group, and a second side portion extending from both end portions in the second direction at the second end portion to the first side in the first direction. A second restraint plate having, and one of the first side portions and one of the second side portions are joined in a state of overlapping each other on the first side in the second direction with respect to the first element group, and the other first side portion and the other second side portion may be joined in a state of overlapping each other on the second side in the second direction with respect to the first element group. According to this aspect, by joining the first side portion and the second side portion, the periphery of the first element row is surrounded by the first inner member. In this case, the first side portion and the second side portion function as an absorption allowance for dimensional errors in the first direction of the first element group. Therefore, for example, compared to a configuration in which the periphery of the first element group is surrounded by a cylindrical member in advance, the first element group can be restrained while applying a predetermined pressure in the first direction to the first element group regardless of dimensional variations.

[0015] (6) In the power storage device according to the aspect (5) above, the first element unit includes a first inner welding portion that joins the one first side portion and the one second side portion, and the other first side portion and the other second side portion. A second inner welding portion to be joined, and an insulating member disposed between the first element group and the first inner member to insulate between the first element group and the first inner member. The insulating member includes a first extension portion that overlaps the first inner welding portion when viewed from the second direction within the first inner member, and a second extension portion that overlaps the second inner welding portion when viewed from the second direction within the first inner member. It may be provided. According to this aspect, since the extension portions are disposed between the power storage elements and the respective welding portions, it is possible to suppress the influence of heat generated during welding of each welding portion from reaching each power storage element.

[0016] (7) In the power storage device according to the aspect (6) above, the dimension in the third direction that intersects the second direction when viewed from the first direction in the first element group is larger than the dimension in the first direction in the first element group, and each of the first inner welding part and the second inner welding part may extend in the third direction and be arranged at intervals in the first direction. According to this aspect, for each welding part, while ensuring the length per piece, the number of each welding part can be reduced. Therefore, the number of reciprocating scans of the welding machine can be reduced, and the manufacturing efficiency can be improved.

[0017] [Embodiment] Next, embodiments of the present disclosure will be described with reference to the drawings. In the embodiments and modifications described below, corresponding configurations may be denoted by the same reference numerals and the description thereof may be omitted. In the following description, expressions indicating relative or absolute arrangements such as "parallel", "orthogonal", "center", "coaxial", etc. not only strictly represent such arrangements, but also represent states in which they are relatively displaced with tolerances and angles and distances that can obtain the same function. Also, in this embodiment, "opposite" includes not only the case where the orthogonal directions (normal directions) of two surfaces coincide with each other, but also the case where the orthogonal directions intersect each other. When expressing "insulation", it means "electrical insulation". The insulating material is preferably formed from a material having a volume resistivity of 1×10 10 Ωm or more.

[0018] <Power storage device 1> FIG. 1 is a perspective view of the power storage device 1. The power storage device 1 shown in FIG. 1 is a device that can charge electricity from the outside and discharge electricity to the outside, and is a battery module (battery pack) used for power storage applications or power supply applications, etc. The power storage device 1 is mounted on a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV), a railway vehicle for electric railways, etc., and is used for driving and starting the moving body. Note that examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, light oil, liquefied natural gas, etc.) automobiles. Examples of the above-mentioned railway vehicles include trains, monorails, linear motor cars, and hybrid trains equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use, etc.

[0019] FIG. 2 is an exploded perspective view of the power storage device 1. As shown in FIG. 2, the power storage device 1 includes a case 10, a power storage module 11, and a connection module 12.

[0020] (Case 10) The case 10 houses the power storage module 11 and the connection module 12 together. The case 10 is formed in a rectangular parallelepiped shape. The case 10 is configured by overlapping a base member 21 and a cover member 22. In the following description, for convenience, a rectangular coordinate system including the X direction, the Y direction, and the Z direction is used to describe each direction. In this case, the overlapping direction of the base member 21 and the cover member 22 is defined as the Z direction (first direction), and the directions orthogonal to each other in the Z direction are defined as the X direction (second direction) and the Y direction (third direction).

[0021] The base member 21 is formed of a material having at least an insulating outer surface, such as a resin material or a metal material with an insulating coating. Examples of the resin material include polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene·perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof, etc.

[0022] The base member 21 includes a base plate 21a and a base protrusion (positioning portion) 21b. The base plate 21a is formed in a rectangular plate shape in a plan view (viewed in the Z direction) with the X direction as the longitudinal direction and the Y direction as the short-side direction. The base protrusion 21b protrudes from the central portion in the X direction of the base plate 21a toward the +Z side and extends in the Y direction.

[0023] Similar to the base member 21, the cover member 22 is formed of a material having at least an insulating outer surface, such as a resin material or a metal material with an insulating coating. The cover member 22 includes a cover body 22a and a cover protrusion (positioning portion) 22b. The outer shape of the cover body 22a in a plan view is a rectangular shape equivalent to that of the base plate 21a, and is formed in a box shape opened on the -Z side. The opening on the -Z side of the cover body 22a is closed by the base plate 21a. Thereby, a space for accommodating the power storage module 11 and the connection module 12 is formed in the portion surrounded by the cover body 22a and the base plate 21a. Note that the joining method between the cover body 22a and the base plate 21a can be appropriately selected, such as adhesion, welding, soldering, caulking, bolt fastening, etc.

[0024] Of the cover body 22a, a first recess 22c is formed at the end on the +Y side and +X side. The first recess 22c is formed so as to straddle the top wall and the side wall of the cover body 22a. The first recess 22c is open in three directions: the +X side, the +Y side, and the +Z side. Of the cover body 22a, a second recess 22d is formed at the end on the +Y side and -X side. The second recess 22d is formed so as to straddle the top wall and the side wall of the cover body 22a. The second recess 22d is open in three directions: the -X side, the +Y side, and the +Z side.

[0025] FIG. 3 is a cross-sectional view corresponding to line III-III in FIG. 1. As shown in FIGS. 2 and 3, the cover protrusion 22b protrudes from the central portion in the X direction of the top wall of the cover body 22a toward the -Z side and extends in the Y direction. The cover protrusion 22b is in proximity or contact with the base protrusion 21b in the Z direction when the cover member 22 and the base member 21 are combined.

[0026] (Power storage module 11) FIG. 4 is an exploded perspective view of the power storage module 11. As shown in FIGS. 2 and 4, the power storage module 11 is formed in a rectangular parallelepiped shape smaller than the case 10. The power storage module 11 includes a first element unit 31, a second element unit 32, and an outer member 33.

[0027] (First element unit 31) The first element unit 31 includes a first element group 41 and a first inner member 42.

[0028] FIG. 5 is an exploded perspective view of the first element group 41. As shown in FIG. 5, the first element group 41 includes a plurality of first power storage elements 51A, 51B and a first holder member (insulating member) 52. Note that the first power storage elements 51A, 51B have the same configuration. Therefore, in the following description, when it is not necessary to distinguish between the first power storage elements 51A, 51B, the first power storage elements 51A, 51B are collectively described as the first power storage element 51.

[0029] The first power storage element 51 is a rechargeable secondary battery (single cell). Specifically, the first power storage element 51 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The first power storage element 51 has a rectangular parallelepiped shape (angular shape) that is flat in the Z-axis direction. The size and shape of the first power storage element 51 are not limited, and the first power storage element 51 may be a cylindrical shape (cylindrical shape), an elliptical cylindrical shape, an elliptical column shape, a polygonal column shape other than a rectangular parallelepiped shape, etc. The first power storage element 51 may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The first power storage element 51 may be a primary battery instead of a secondary battery. Also, the first power storage element 51 may be a battery using a solid electrolyte.

[0030] The first power storage element 51 includes an electrode body (not shown), an exterior body 55 that houses the electrode body, and a terminal 56 provided on the exterior body 55. The electrode body is a so-called wound type electrode body, which is formed by winding a positive electrode plate, a negative electrode plate, and a separator in a stacked state. However, the electrode body is not limited to the wound type. That is, the electrode body may be any form of electrode body, such as a laminated type (stacked type) electrode body formed by laminating a plurality of flat electrode plates, or a bellows type electrode body in which the electrode plate is folded in a bellows shape.

[0031] The exterior body 55 includes a container 61 having an opening 61a and a lid body 62 that closes the opening 61a of the container 61. The container 61 and the lid body 62 are formed of a weldable metal such as stainless steel, aluminum, or an aluminum alloy, for example. However, the container 61 and the lid body 62 may be formed of a resin material or the like. The container 61 is formed in a bottomed cylindrical shape that is flat in the Z direction and opens on the +Y side. Inside the container 61, the electrode body is housed together with an electrolytic solution (non-aqueous electrolyte). The lid body 62 is a plate-like member that closes the opening 61a of the container 61. After the electrode body is housed in the container 61, the lid body 62 is joined to the opening edge of the opening 61a of the container 61 by welding or the like. Thereby, the inside of the container 61 is sealed.

[0032] A gas discharge valve 62a is provided at the central portion of the lid body 62 in the X direction. The gas discharge valve 62a is for releasing the pressure inside the exterior body 55 by being broken when the pressure inside the exterior body 55 rises to a predetermined value or more.

[0033] The terminals 56 are respectively provided at both ends of the lid body 62 in the X direction. A part of the terminal 56 penetrates the lid body 62 in the Y direction while being exposed to the outside of the lid body 62. Among the terminals 56, the portion located inside the exterior body 55 is connected to the electrode body.

[0034] The plurality of first power storage elements 51 are arranged in a line in the Z direction with the thickness direction of the exterior body 55 along the Z direction. In the present embodiment, a state where two first power storage elements 51 are arranged side by side is shown. However, the number of the first power storage elements 51 may be three or more.

[0035] The first holder member 52 includes an intermediate holder 71 positioned between the first power storage elements 51A and 51B adjacent to each other in the Z direction, a first end holder 72 arranged on the +Z side with respect to the first power storage element 51A, and a second end holder 73 arranged on the -Z side with respect to the first power storage element 51B. The intermediate holder 71 is a member that is positioned between the first power storage elements 51 adjacent to each other in the Z direction and insulates between the first power storage elements 51. The intermediate holder 71 is formed of an insulating material such as a resin material.

[0036] FIG. 6 is a cross-sectional view corresponding to the line VI-VI in FIG. 1. As shown in FIGS. 5 and 6, the intermediate holder 71 is formed in an H shape in a cross-sectional view when viewed from the Y direction. The intermediate holder 71 includes a clamping wall 71a and an intermediate peripheral wall portion 71b. The clamping wall 71a has the Z direction as the thickness direction, and the outer shape in a plan view is formed in a rectangular shape larger than the first power storage element 51 (exterior body 55). The clamping wall 71a is sandwiched from both sides in the Z direction by the first power storage elements 51A and 51B.

[0037] The intermediate peripheral wall portion 71b is continuous with the outer peripheral edge of the clamping wall 71a. The intermediate peripheral wall portion 71b protrudes on both sides in the Z direction with respect to the clamping wall 71a and surrounds the clamping wall 71a over the entire circumference. A part (-Z side portion) of the first power storage element 51A is accommodated in the space surrounded by the intermediate peripheral wall portion 71b and located on the +Z side with respect to the clamping wall 71a. A part (+Z side portion) of the first power storage element 51B is accommodated in the space surrounded by the intermediate peripheral wall portion 71b and located on the -Z side with respect to the clamping wall 71a.

[0038] In the portion of the intermediate peripheral wall portion 71b located on the +X side, a +X side abutting portion 71e is formed. The +X side abutting portion 71e protrudes from the central portion in the Z direction of the intermediate peripheral wall portion 71b toward the +X side and extends in the Y direction. In the portion of the intermediate peripheral wall portion 71b located on the -X side, a -X side abutting portion 71f is formed. The -X side abutting portion 71f protrudes from the central portion in the Z direction of the intermediate peripheral wall portion 71b toward the -X side and extends in the Y direction.

[0039] The first end holder 72 is superposed on the first power storage element 51A from the +Z side. The first end holder 72 is formed of an insulating material such as a resin material. The first end holder 72 is formed in a box shape that opens on the -Z side.

[0040] The first end holder 72 includes a first support wall 72a and a first peripheral wall portion 72b. The first support wall 72a has the Z direction as the thickness direction, and the outer shape in plan view is formed in a rectangular shape having the same size as the clamping wall 71a. The clamping wall 71a and the first support wall 72a sandwich the first power storage element 51A between the clamping wall 71a and the first support wall 72a. A first positioning protrusion 72c (see FIG. 4) is formed on the first support wall 72a. The first positioning protrusion 72c protrudes from the central portion in the X direction of the first support wall 72a toward the +Z side. In the illustrated example, a plurality of first positioning protrusions 72c are formed at intervals in the Y direction.

[0041] The first peripheral wall portion 72b protrudes from the outer peripheral edge of the first support wall 72a toward the -Z side and surrounds the first support wall 72a over the entire circumference. A part (+Z side portion) of the first power storage element 51A is accommodated in the space surrounded by the first peripheral wall portion 72b. The edge on the -Z side of the first peripheral wall portion 72b is close to or in contact with the edge on the +Z side of the intermediate peripheral wall portion 71b. That is, the periphery of the first power storage element 51A is covered by the intermediate holder 71 and the first end holder 72.

[0042] The second end holder 73 is superposed on the first power storage element 51B from the -Z side. The second end holder 73 is formed of an insulating material such as a resin material. The second end holder 73 is formed in a box shape that opens on the +Z side.

[0043] The second end holder 73 has a configuration that is inverted in the Z direction with respect to the first end holder 72. Specifically, the second end holder 73 includes a second support wall 73a and a second peripheral wall portion 73b. The clamping wall 71a and the second support wall 73a sandwich the first power storage element 51B between the clamping wall 71a and the second support wall 73a. A second positioning protrusion 73c is formed on the second support wall 73a. The second positioning protrusion 73c protrudes from the central portion in the X direction of the second support wall 73a toward the -Z side. In the illustrated example, a plurality of second positioning protrusions 73c are formed at intervals in the Y direction.

[0044] The second peripheral wall portion 73b protrudes from the outer peripheral edge of the second support wall 73a toward the +Z side and surrounds the second support wall 73a over the entire circumference. A part (-Z side portion) of the first power storage element 51B is accommodated in the space surrounded by the second peripheral wall portion 73b. The edge on the +Z side of the second peripheral wall portion 73b is close to or in contact with the edge on the -Z side of the intermediate peripheral wall portion 71b. That is, the periphery of the first power storage element 51B is covered by the intermediate holder 71 and the second end holder 73.

[0045] As shown in FIG. 4, in the first holder member 52, a first relief portion 75 and a second relief portion 76 are formed in a portion located on the +Y side with respect to the first power storage element 51. The first relief portion 75 is formed so as to penetrate portions that overlap with the terminal 56 or the gas discharge valve 62a of the first power storage element 51A when viewed in the Y direction, in a portion of the intermediate peripheral wall portion 71b located on the +Y side and a portion of the first peripheral wall portion 72b located on the +Y side. The first relief portion 75 exposes the terminal 56 and the gas discharge valve 62a of the first power storage element 51A to the outside of the first holder member 52, respectively.

[0046] The second relief portion 76 is formed so as to penetrate portions that overlap with the terminal 56 or the gas discharge valve 62a of the first power storage element 51B when viewed in the Y direction, in a portion of the intermediate peripheral wall portion 71b located on the +Y side and a portion of the second peripheral wall portion 73b located on the +Y side. The second relief portion 76 exposes the terminal 56 or the gas discharge valve 62a of the first power storage element 51B to the outside of the first holder member 52.

[0047] A flange portion 77 is formed on the outer peripheral edge of the portion of the first holder member 52 located on the +Y side with respect to the first power storage element 51. The flange portion 77 projects in a direction orthogonal to the Y direction from the outer peripheral edge on the +Y side so as to surround the outer peripheral edge on the +Y side of the first holder member 52.

[0048] In this way, the first element group 41 is configured by sequentially laminating the first end holder 72, the first power storage element 51A, the intermediate holder 71, the first power storage element 51B, and the second end holder 73 from the +Z side to the -Z side. In this case, in the first element group 41, the first holder member 52 is disposed between the first power storage elements 51A and 51B and around the first power storage elements 51A and 51B, so that each of the first power storage elements 51A and 51B is insulated. Note that the dimension of the first element group 41 in the Z direction is smaller than the dimension in the Y direction. However, the dimension of the first element group 41 can be appropriately changed.

[0049] The first inner member 42 collectively sandwiches the first element group 41 in the Z direction and restrains the first element group 41 in the Z direction. Note that "restraining" the first element group 41 means restricting the relative displacement in the Z direction between the constituent members (the first power storage element 51 and the first holder member 52) of the first element group 41.

[0050] The first inner member 42 is formed in an angle tube shape that surrounds the periphery of the first element group 41 when viewed from the Y direction. The first inner member 42 includes a first restraint plate 81 and a second restraint plate 82. The first restraint plate 81 is integrally formed in a U shape that opens to the -Z side when viewed from the Y direction. The first restraint plate 81 is assembled to the first element group 41 so as to surround the first element group 41 from both the +Z side and both sides in the X direction. The first restraint plate 81 is preferably a member to which a metal material is applied and which has excellent rigidity compared to the exterior body 55 and the first holder member 52. Note that rigidity is defined such that when the same load is applied, the member with the larger amount of deformation is considered to have "low rigidity", and the member with the smaller amount of deformation is considered to have "high rigidity". That is, a member with high rigidity can be rephrased as a member with superior rigidity compared to a member with low rigidity.

[0051] FIG. 7 is a cross-sectional view corresponding to the VII-VII line in FIG. 1. As shown in FIGS. 4, 6, and 7, the first restraint plate 81 includes a first end portion 81a, a +X side portion (first side portion) 81b, and a -X side portion (first side portion) 81c. The first end portion 81a is formed in a rectangular plate shape with an outer shape in plan view equivalent to that of the first support wall 72a. The first end portion 81a is superposed on the first support wall 72a from the +Z side. As shown in FIGS. 4 and 7, an inner positioning hole 81a1 is formed in a portion of the first end portion 81a that overlaps with the positioning projection 72c in plan view. The inner positioning hole 81a1 individually accommodates the positioning projection 72c. By the positioning projection 72c contacting the inner peripheral edge of the inner positioning hole 81a1, the movement of the first element group 41 in the X direction or the Y direction with respect to the first restraint plate 81 is restricted.

[0052] As shown in FIGS. 4 and 6, the +X side portion 81b extends from the +X side edge of the first end portion 81a toward the -Z side. The +X side portion 81b covers the first holder member 52 from the +X side. In the illustrated example, the -Z side edge of the +X side portion 81b is on the -Z side of the +X side abutting portion 71e and on the +Z side of the second support wall 73a. That is, the +X side portion 81b overlaps the first end holder 72, the intermediate holder 71, and the second end holder 73 when viewed in the X direction.

[0053] A first side bead 81b1 is formed on the +X side portion 81b. The first side bead 81b1 extends over the entire length of the +X side portion 81b in the Y direction with a part of the +X side portion 81b bulging toward the +X side. In the illustrated example, the first side bead 81b1 is formed at the -Z side end of the +X side portion 81b. Further, a through hole 81b2 is formed in a portion of the +X side portion 81b that is located on the +Z side with respect to the first side bead 81b1.

[0054] The -X side portion 81c extends from the -X side edge of the first end portion 81a toward the -Z side. The -X side portion 81c covers the first holder member 52 from the -X side. In the illustrated example, the -X side portion 81c is formed to have the same length as the +X side portion 81b. That is, the -X side portion 81c overlaps the first end holder 72, the intermediate holder 71, and the second end holder 73 when viewed in the X direction. A through hole 81c1 is formed at the +Z side end of the -X side portion 81c. Note that the first restraint plate 81 is in proximity to or in contact with the flange portion 77 in the Y direction when assembled to the first element group 41.

[0055] The second restraint plate 82 is integrally formed in a U shape that opens on the +Z side when viewed from the Y direction. The second restraint plate 82 surrounds the first element group 41 from both the -Z side and both sides in the X direction. Similar to the first restraint plate 81, the second restraint plate 82 is preferably made of a material with higher rigidity than the exterior body 55 and the first holder member 52. Note that the second restraint plate 82 may be made of the same type of material as the first restraint plate 81 or a different type of material.

[0056] The second restraint plate 82 includes a second end portion 82a, a +X side portion (second side portion) 82b, and a -X side portion (second side portion) 82c. The second end portion 82a is formed in a rectangular plate shape with an outer shape in plan view equivalent to that of the second support wall 73a. The second end portion 82a is overlapped with the second support wall 73a from the -Z side. As shown in FIG. 7, an inner positioning hole 82a1 is formed in a portion of the second end portion 82a that overlaps with the second positioning protrusion 73c in plan view. The inner positioning hole 82a1 individually accommodates the second positioning protrusion 73c. By the second positioning protrusion 73c contacting the inner peripheral edge of the inner positioning hole 82a1, the movement of the first element group 41 in the X direction or the Y direction with respect to the second restraint plate 82 is restricted.

[0057] As shown in FIGS. 4 and 6, the +X side portion 82b extends from the +X side edge of the second end portion 82a toward the +Z side. The +X side portion 82b covers the first holder member 52 from the +X side inside the first restraint plate 81. In the illustrated example, the +Z side edge of the +X side portion 82b is on the +Z side of the +X side abutting portion 71e and on the -Z side of the first support wall 72a. The +X side portion 82b of the second restraint plate 82 is sandwiched in the X direction between the +X side portion 81b of the first restraint plate 81 and the first holder member 52. That is, at least a part of the +X side portion 82b of the second restraint plate 82 overlaps with the +X side portion 81b of the first restraint plate 81. In the illustrated example, the portion of the +X side portion 81b of the first restraint plate 81 that is located on the -Z side with respect to the through hole 81b2 and includes the first side bead 81b1 overlaps with the +X side portion 82b of the second restraint plate 82 over the entire Y direction. In the present embodiment, the +X side portion 82b of the second restraint plate 82 is close to or in contact with the +X side abutting portion 71e.

[0058] As shown in FIGS. 2 and 6, in the overlapping portion (hereinafter referred to as the +X side overlapping portion 86) of the +X side portion 81b of the first restraint plate 81 and the +X side portion 82b of the second restraint plate 82 when viewed in the X direction, a +X side welding portion (first inner welding portion) 87 for joining the +X side portions 81b and 82b is formed. In the present embodiment, the +X side overlapping portion 86 overlaps with the intermediate peripheral wall portion (first extension portion) 71b of the intermediate holder 71 and the second peripheral wall portion (first extension portion) 73b of the second end holder 73 when viewed in the X direction. However, the +X side overlapping portion 86 only needs to overlap with any of the first holder members 52 between the +X side overlapping portion 86 and the first power storage element 51.

[0059] The +X side welding part 87 is a welding mark where the +X side side parts 81b and 82b are joined together by, for example, laser welding or the like. The +X side welding part 87 extends linearly over the entire length in the Y direction in the +X side overlapping part 86. In the present embodiment, a plurality of (for example, two) +X side welding parts 87 are provided at intervals in the Z direction. Further, in the present embodiment, any one of the +X side welding parts 87 is provided at a position overlapping at least the first side bead 81b1 among the +X side overlapping parts 86.

[0060] As shown in FIG. 6, the -X side side part 82c extends from the -X side edge of the second end part 82a to the +Z side. The -X side side part 82c covers the first holder member 52 from the -X side inside the first restraint plate 81. In the illustrated example, the +Z side edge of the -X side side part 82c is on the +Z side of the -X side abutting part 71f and on the -Z side of the first support wall 72a. The -X side side part 82c of the second restraint plate 82 is sandwiched in the X direction between the -X side side part 81c of the first restraint plate 81 and the first holder member 52. That is, at least a part of the -X side side part 82c of the second restraint plate 82 overlaps the -X side side part 81c of the first restraint plate 81. In the illustrated example, the portion of the -X side side part 81c of the first restraint plate 81 located on the -Z side with respect to the through hole 81c1 overlaps the -X side side part 82c of the second restraint plate 82 over the entire Y direction. Note that, in the present embodiment, the -X side side part 82c of the second restraint plate 82 is close to or in contact with the -X side abutting part 71f.

[0061] Of the -X side portions 81c of the first restraint plate 81 and the -X side portions 82c of the second restraint plate 82, a portion that overlaps when viewed in the X direction (hereinafter referred to as the - side overlapping portion 88) is formed with a -X side welding portion (second inner welding portion) 89 that joins the -X side portions 81c and 82c together. In the present embodiment, the -X side welding portion 89 overlaps the intermediate peripheral wall portion (second extension portion) 71b of the intermediate holder 71 and the second peripheral wall portion (second extension portion) 73b of the second end holder 73 when viewed in the X direction. However, the -X side overlapping portion 87 only needs to overlap any of the first holder members 52 between the -X side overlapping portion 87 and the first power storage element 51.

[0062] The -X side welding portion 89 is a weld mark formed by joining the -X side portions 81c and 82c together by, for example, laser welding or the like. The -X side welding portion 89 extends linearly over the entire length in the Y direction in the -X side overlapping portion 88. In the present embodiment, a plurality of (for example, two) -X side welding portions 89 are provided at intervals in the Z direction.

[0063] In the present embodiment, the +X side welding portion 87 and the -X side welding portion 89 are formed at the same position in the Z direction. However, the +X side welding portion 87 and the -X side welding portion 89 may be formed at different positions in the Z direction. Also, the number of the +X side welding portion 87 and the -X side welding portion 89 may be the same or different. At least one of the +X side welding portion 87 and the -X side welding portion 89 may be formed. In the present embodiment, the +X side welding portion 87 and the -X side welding portion 89 have been described as having a configuration that extends linearly in the Y direction, but the configuration is not limited thereto. The length of the +X side welding portion 87 in the Y direction and the length of the -X side welding portion 89 in the Y direction may be different. The +X side welding portion 87 and the -X side welding portion 89 may extend in the Z direction or may extend in the Y direction while meandering in the Z direction.

[0064] (Second element unit 32) FIG. 8 is a cross-sectional view corresponding to line VIII-VIII in FIG. 1. As shown in FIGS. 4 and 8, the second element unit 32 is disposed on the -X side of the first element unit 31 in the case 10 with a gap in the X direction with respect to the first element unit 31. The second element unit 32 has the same configuration as the first element unit 31. The second element unit 32 is formed line-symmetric with respect to the first element unit 31 with respect to an imaginary line extending in the Z direction from the end on the -X side of the first element unit 31 as viewed in the Y direction. Therefore, hereinafter, for the configuration similar to that of the first element unit 31 in the second element unit 32, the same reference numerals as those of the first element unit 31 will be given and the description will be omitted as appropriate.

[0065] The second element unit 32 includes a second element group 101 and a second inner member 102. The second element group 101 includes a plurality of second power storage elements 105A and 105B and a second holder member (insulating member) 106. The second power storage elements 105A and 105B have the same configuration. Therefore, in the following description, when it is not necessary to distinguish between the second power storage elements 105A and 105B, the second power storage elements 105A and 105B will be collectively described as the second power storage element 105.

[0066] The second power storage element 105 is a rechargeable secondary battery having the same shape and the same size as the first power storage element 51. The second power storage elements 105 are arranged in a row in the Z direction with the same number (two) as the first power storage element 51.

[0067] Similar to the first holder member 52, the second holder member 106 includes an intermediate holder 71, a first end holder 72, and a second end holder 73. The intermediate holder 71 is disposed between the second power storage elements 105A and 105B adjacent to each other in the Z direction. The first end holder 72 is disposed on the +Z side with respect to the second power storage element 105A. The periphery of the second power storage element 105A is surrounded by the intermediate holder 71 and the first end holder 72. The second end holder 73 is disposed on the -Z side with respect to the second power storage element 105B. The periphery of the second power storage element 105B is surrounded by the intermediate holder 71 and the second end holder 73.

[0068] The second inner member 102 collectively sandwiches the second element group 101 in the Z direction to restrain the second element group 101 in the Z direction. The second inner member 102 is formed in a rectangular tube shape that surrounds the periphery of the second element group 101 when viewed from the Y direction. Similar to the first inner member 42, the second inner member 102 includes a first restraint plate 110 and a second restraint plate 111. The first restraint plate 110 surrounds the second element group 101 from both the +Z side and both sides in the X direction. The first restraint plate 110 includes a first end portion 110a, a +X side side portion (first side portion) 110b, and a -X side side portion (first side portion) 110c. The first end portion 110a is superposed on the first support wall 72a of the second holder member 106 from the +Z side. An inner positioning hole 110a1 is formed in a portion of the first end portion 110a that overlaps the first positioning protrusion 72c in plan view. The inner positioning holes 110a1 respectively accommodate the positioning protrusions 72c. When the positioning protrusions 72c contact the inner peripheral edge of the inner positioning holes 110a1, the movement of the second element group 101 in the X direction or the Y direction with respect to the first restraint plate 110 is restricted.

[0069] The +X side side portion 110b extends from the +X side edge of the first end portion 110a to the -Z side. The +X side side portion 110b covers the second holder member 106 from the +X side. - The -X side portion 110c extends from the -X side edge of the first end portion 110a toward the -Z side. The -X side portion 110c covers the second holder member 106 from the -X side. As shown in FIG. 8, a second side bead 110c1 is formed on the -X side portion 110c. The second side bead 110c1 extends over the entire length of the -X side portion 110c in the Y direction with a part of the -X side portion 110c bulging toward the -X side. A through hole 110c2 is formed in a portion of the -X side portion 110c that is located on the +Z side with respect to the second side bead 110c1.

[0070] The second restraint plate 111 surrounds the second element group 101 from both the -Z side and both sides in the X direction. The second restraint plate 111 includes a second end portion 111a, a +X side portion (second side portion) 111b, and a -X side portion (second side portion) 111c. The second end portion 111a is overlapped with the second support wall 73a of the second holder member 106 from the -Z side. An inner positioning hole 111a1 is formed in a portion of the second end portion 111a that overlaps with the second positioning projection 73c in plan view. The inner positioning hole 111a1 individually accommodates the second positioning projection 73c. By the second positioning projection 73c contacting the inner peripheral edge of the inner positioning hole 111a1, the movement of the second element group 101 in the X direction or the Y direction with respect to the second restraint plate 111 is restricted.

[0071] The +X side portion 111b extends from the +X side edge of the second end portion 111a toward the +Z side. The +X side portion 111b covers the second holder member 106 from the +X side inside the first restraint plate 110. In the present embodiment, the +X side portion 111b of the second restraint plate 111 is close to or in contact with the -X abutting portion 71f.

[0072] Of the +X side portions 110b of the first restraint plate 110 and the +X side portions 111b of the second restraint plate 111, a portion that overlaps when viewed in the X direction (hereinafter referred to as the + side overlapping portion 115) is formed with a +X side weld portion (first inner weld portion) 116 that joins the +X side portions 110b and 111b together. In the present embodiment, the +X side overlapping portion 115 overlaps the intermediate peripheral wall portion (first extension portion) 71b of the intermediate holder 71 and the second peripheral wall portion (first extension portion) 73b of the second end holder 73 when viewed in the X direction. However, the +X side overlapping portion 115 only needs to overlap any of the second inner members 102 between the +X side overlapping portion 115 and the second power storage element 105.

[0073] The +X side weld portion 116 is a weld mark formed by joining the +X side portions 110b and 111b together by, for example, laser welding or the like. The +X side weld portion 116 extends linearly over the entire length in the Y direction in the +X side overlapping portion 115. In the present embodiment, a plurality of (for example, two) +X side weld portions 116 are provided at intervals in the Z direction.

[0074] The -X side portion 111c extends from the -X side edge of the second end portion 111a to the +Z side. The -X side portion 111c covers the second holder member 106 from the -X side inside the first restraint plate 110. In the present embodiment, the -X side portion 111c of the second restraint plate 111 is close to or in contact with the -X side abutting portion 71f.

[0075] Of the -X side portions 110c of the first restraint plate 110 and the -X side portions 111c of the second restraint plate 111, a portion that overlaps when viewed from the X direction (hereinafter referred to as the -X side overlapping portion 117) is formed with a -X side welding portion (second inner welding portion) 118 that joins the -X side portions 110c and 111c together. In the present embodiment, the -X side overlapping portion 117 overlaps the intermediate peripheral wall portion (second extension portion) 71b of the intermediate holder 71 and the second peripheral wall portion (second extension portion) 73b of the second end holder 73 when viewed from the X direction. However, the -X side overlapping portion 117 only needs to overlap any of the second inner members 102 between the -X side overlapping portion 117 and the second power storage element 105.

[0076] The -X side welding portion 118 is a weld mark formed by joining the -X side portions 110c and 111c together by, for example, laser welding or the like. The -X side welding portion 118 extends linearly over the entire length in the Y direction in the -X side overlapping portion 117. In the present embodiment, a plurality of (for example, two) -X side welding portions 118 are provided at intervals in the Z direction. Also, in the present embodiment, any one of the -X side welding portions 118 is provided at a position that overlaps at least the second side bead 110c1 in the -X side overlapping portion 117.

[0077] (Outer member 33) As shown in FIG. 4, the outer member 33 is joined to the inner members 42 and 102 of each of the element units 31 and 32 in a state of straddling in the Y direction between the first element unit 31 and the second element unit 32 arranged in the X direction. The outer member 33 restrains the first element unit 31 and the second element unit 32 and regulates the relative displacement between the first element unit 31 and the second element unit 32. Specifically, the outer member 33 includes a first outer plate 120 disposed on the +Z side with respect to the first element unit 31 and the second element unit 32, and a second outer plate 121 disposed on the -Z side with respect to the first element unit 31 and the second element unit 32.

[0078] The first outer plate 120 is formed in a rectangular shape with the X direction as the longitudinal direction and the Y direction as the short side direction in a plan view. The first outer plate 120 overlaps the entire first end portions 81a and 110a in a plan view so as to straddle only the portion facing the +Z side among the first element unit 31 and the second element unit 32 in the X direction. Note that if the first outer plate 120 is arranged so as to straddle between the first element unit 31 and the second element unit 32, it may be arranged in a part in the Y direction between the first element unit 31 and the second element unit 32.

[0079] As shown in FIGS. 2 and 8, a first slit (engagement portion) 120a is formed at the central portion in the X direction of the first outer plate 120. The first slit 120a penetrates in the Z direction at a position that overlaps with the gap between the first element unit 31 and the second element unit 32 in a plan view of the first outer plate 120. Note that both ends in the Y direction of the first slit 120a are arranged inside the first outer plate 120.

[0080] An outer positioning hole 120b is formed at a portion of the first outer plate 120 that overlaps with the inner positioning holes 81a1 and 110a1 in a plan view. The outer positioning hole 120b separately houses the first positioning protrusions 72c that protrude through the inner positioning holes 81a1 and 110a1. By the first positioning protrusions 72c coming into contact with the inner peripheral edge of the outer positioning hole 120b, the movement of the first element unit 31 and the second element unit 32 in the X direction or the Y direction with respect to the first outer plate 120 is restricted. Note that the first outer plate 120 is in proximity to or in contact with the flange portion 77 in the Y direction in a state of being overlapped with the first element unit 31 and the second element unit 32 (see FIG. 3).

[0081] On the first outer plate 120, a first outer bead 120c is formed. The first outer bead 120c extends over the entire length of the first outer plate 120 in the Y direction in a state where a part of the first outer plate 120 bulges toward the +Z side. A plurality of first outer beads 120c are formed at intervals in the X direction at positions overlapping with the first element unit 31 or the second element unit 32 in a plan view.

[0082] In the overlapping portion (hereinafter referred to as the +Z side overlapping portion 125) of the first outer plate 120 and the first end portions 81a, 110a in a plan view, a +Z side welding portion (first outer welding portion) 126 is formed. The +Z side welding portion 126 is a welding mark formed by joining the first outer plate 120 and the first end portions 81a to each other, or the first outer plate 120 and the first end portions 110a to each other by, for example, laser welding or the like. The +Z side welding portion 126 extends linearly over the entire length in the Y direction in the +Z side overlapping portion 125. In the present embodiment, a plurality of (for example, six) +Z side welding portions 126 are provided at intervals in the X direction. Further, in the present embodiment, any one of the +Z side welding portions 126 is provided at a position overlapping at least the first outer bead 120c in the +Z side overlapping portion 125.

[0083] As shown in FIGS. 4 and 8, the second outer plate 121 is formed in a rectangular shape having the X direction as the longitudinal direction and the Y direction as the short side direction in a plan view. The second outer plate 121 overlaps the entire second end portions 82a, 111a in a plan view so as to straddle only the portion facing the -Z side among the first element unit 31 and the second element unit 32 in the X direction.

[0084] In the central portion of the second outer plate 121 in the X direction, a second slit (engagement portion) 121a is formed. The second slit 121a penetrates in the Z direction at a position overlapping the first slit 120a in a plan view.

[0085] As shown in FIG. 8, an outer positioning hole 121b is formed in a portion of the second outer plate 121 that overlaps the inner positioning holes 82a1 and 111a1 in a plan view. The outer positioning hole 121b separately accommodates positioning protrusions 73c that protrude through the inner positioning holes 82a1 and 111a1. When the positioning protrusions 73c contact the inner peripheral edge of the outer positioning hole 121b, the movement of the first element unit 31 and the second element unit 32 in the X direction or the Y direction with respect to the second outer plate 121 is restricted. Note that the second outer plate 121 is in proximity to or in contact with the flange portion 77 in the Y direction in a state where it is superimposed on the first element unit 31 and the second element unit 32 (see FIG. 3).

[0086] A second outer bead 121c is formed on the second outer plate 121. The second outer bead 121c extends over the entire length of the second outer plate 121 in the Y direction in a state where a part of the second outer plate 121 bulges toward the -Z side. A plurality of second outer beads 121c are formed at intervals in the X direction at positions that overlap the first element unit 31 or the second element unit 32 in a plan view.

[0087] A -Z side welding portion 128 is formed in a portion where the second outer plate 121 and the second end portions 82a and 111a overlap in a plan view (hereinafter referred to as a -Z side overlapping portion 127). The -Z side welding portion (second outer welding portion) 128 is a welding mark formed by joining the second outer plate 121 and the second end portion 82a or the second outer plate 121 and the second end portion 111a to each other by, for example, laser welding or the like. The -Z side welding portion 128 extends linearly over the entire length of the -Z side overlapping portion 127 in the Y direction. In the present embodiment, a plurality of (for example, six) -Z side welding portions 128 are provided at intervals in the X direction. Also, in the present embodiment, any one of the -Z side welding portions 128 is provided at a position that overlaps at least the second outer bead 121c in the -Z side overlapping portion 127.

[0088] The power storage module 11 is housed in the case 10 with the cover protrusion 22b inserted into the first slit 120a and the base protrusion 21b inserted into the second slit 121a.

[0089] (Connection module 12) As shown in FIG. 2, the connection module 12 includes a cover plate 130, a plurality of bus bar units 131, and connection terminals (the first connection terminal 132 and the second connection terminal 133 shown in FIG. 1). The cover plate 130 covers the power storage module 11 from the +Y side. The cover plate 130 is formed of an insulating material such as a resin material. The cover plate 130 is formed in a rectangular shape having the same size as the power storage module 11 when viewed from the Y direction. Exposed holes 130a are formed in portions of the cover plate 130 that overlap the respective terminals 56 when viewed from the Y direction. The terminals 56 are exposed in the corresponding exposed holes 130a.

[0090] The bus bar unit 131 includes a first connection bus bar 131a, a second connection bus bar 131b, a third connection bus bar 131d, a first lead-out bus bar 131e, and a second lead-out bus bar 131f.

[0091] The first connection bus bar 131a connects the terminals 56 of the same polarity of the first power storage elements 51A and 51B in the first element group 41. Specifically, the first connection bus bar 131a connects the terminals 56 located on the +X side of the first power storage elements 51A and 51B through the exposed holes 130a. The second connection bus bar 131b connects the terminals 56 of the same polarity of the second power storage elements 105A and 105B in the second element group 101. Specifically, the second connection bus bar 131b connects the terminals 56 located on the +X side of the second power storage elements 105A and 105B through the exposed holes 130a. The third connection bus bar 131c connects the terminals 56 of the first power storage element 51B and the second power storage element 105B. Specifically, the third connection bus bar 131c connects the terminal 56 located on the -X side of the first power storage element 51B and the terminal 56 located on the +X side of the second power storage element 105B through the exposure hole 130a.

[0092] The first lead-out bus bar 131e connects between the first power storage element 51A and the first connection terminal 132. Specifically, the first end of the first lead-out bus bar 131e is connected to the terminal 56 located on the -X side of the first power storage element 51A through the exposure hole 130a. The second end of the first lead-out bus bar 131e is connected to the first connection terminal 132 through a control board (not shown) or the like. The second lead-out bus bar 131f connects between the second power storage element 105A and the second connection terminal 133. Specifically, the first end of the second lead-out bus bar 131f is connected to the terminal 56 located on the +X side of the second power storage element 105A through the exposure hole 130a. The second end of the second lead-out bus bar 131f is connected to the second connection terminal 133 through a control board (not shown) or the like.

[0093] As shown in FIG. 1, the first connection terminal 132 penetrates the bottom wall of the first recess 22c in the Z direction. The end portion on the -Z side of the first connection terminal 132 is connected to the first lead-out bus bar 131e inside the case 10. The end portion on the +Z side of the first connection terminal 132 is connected to the first wiring (not shown) of the moving body. The second connection terminal 133 penetrates the bottom wall of the second recess 22d in the Z direction. The end portion on the -Z side of the second connection terminal 133 is connected to the second lead-out bus bar 131f inside the case 10. The end portion on the +Z side of the second connection terminal 133 is connected to the second wiring (not shown) of the moving body.

[0094] <Manufacturing method of the power storage device 1> Next, as a manufacturing method of the power storage device 1, the manufacturing method of the power storage module 11 will be mainly described. The storage module 11 is manufactured through a first element unit manufacturing process, a second element unit manufacturing process, and an outer restraint process.

[0095] As shown in FIG. 5, in the first element unit manufacturing process, first, a first element group 41 is manufactured (element lamination process). Specifically, in the element lamination process, a first end holder 72, a first storage element 51A, an intermediate holder 71, a first storage element 51B, and a second end holder 73 are sequentially laminated from the +Z side to the -Z side.

[0096] As shown in FIG. 4, in the first element unit manufacturing process, a first inner member 42 is set on the first element group 41 (plate setting process). In the plate setting process, the first element group 41 is sandwiched from both sides in the Z direction by a first restraint plate 81 and a second restraint plate 82. Specifically, with the inner positioning hole 82a1 and the second positioning projection 73c aligned, the first element group 41 is set inside the second restraint plate 82. Then, with the inner positioning hole 81a1 and the first positioning projection 72c aligned, the first restraint plate 81 is placed over the first element group 41. As a result, the +X side portions 81b, 82b of the respective restraint plates 81, 82 and the -X side portions 81c, 82c are overlapped when viewed in the X direction.

[0097] Then, in the first element unit manufacturing process, the first restraint plate 81 and the second restraint plate 82 are joined (inner restraint process). In the inner restraint process, with respect to the first element unit 31 that has undergone the plate setting process, the first restraint plate 81 and the second restraint plate 82 are joined in a state where a load is applied in a direction approaching in the Z direction. Specifically, by reciprocally scanning the welding machine in the Y direction, the +X side overlapping portion 86 is welded along the Y direction, and the -X side overlapping portion 88 is welded along the Y direction. Thereby, the first element unit 31 is completed. In addition, in the inner restraint process, by performing welding at least at a position overlapping with the first side bead 81b1, the air between the +X side portions 81b, 82b is pushed out in the Y direction through between the first side bead 81b1 and the +X side portion 82b. Thereby, it is easy to suppress the remaining air between the +X side portions 81b, 82b.

[0098] The second element unit manufacturing process includes an element stacking process, a plate setting process, and an inner restraint process, similar to the first element unit manufacturing process. In the element stacking process, in the second element stacking process, the first end holder 72, the second power storage element 105A, the intermediate holder 71, the second power storage element 105B, and the second end holder 73 are sequentially stacked from the +Z side to the -Z side.

[0099] Subsequently, in the plate setting process, the second element group 101 is sandwiched from both sides in the Z direction by the first restraint plate 110 and the second restraint plate 111. In the inner restraint process, among the first restraint plate 110 and the second restraint plate 111, the +X side overlapping portion 115 is welded along the Y direction, and the -X side overlapping portion 117 is welded along the Y direction. Thereby, the second element unit 32 is completed.

[0100] Subsequently, in the outer restraint process, with the first element unit 31 and the second element unit 32 arranged in the X direction, the first outer plate 120 and the second outer plate 121 sandwich the first element unit 31 and the second element unit 32 from both sides in the Z direction. At this time, the first outer plate 120 is superposed on the first element unit 31 and the second element unit 32 from the +Z side with the outer positioning hole 120b and the first positioning projection 72c aligned. The second outer plate 121 is superposed on the first element unit 31 and the second element unit 32 from the -Z side with the outer positioning hole 121b and the second positioning projection 73c aligned.

[0101] In the outer restraint process, with a load applied in a direction in which the first outer plate 120 and the second outer plate 121 approach each other in the Z direction, the first outer plate 120 and the first end portions 81a, 110a, and the second outer plate 121 and the second end portions 82a, 111a are welded. Thus, the power storage module 11 is completed.

[0102] Next, the connection module 12 is assembled to the power storage module 11. Thereafter, the power storage module 11 and the connection module 12 are set in the case 10. Specifically, the power storage module 11 is set on the base plate 21a such that the base protrusion 21b is inserted into the second slit 121a. Subsequently, the cover member 22 is placed over the power storage module 11 such that the cover protrusion 22b is inserted into the first slit 120a. Thereafter, the cover main body 22a and the base plate 21a are joined. Thus, the power storage device 1 is completed.

[0103] As described above, the power storage device 1 of the present embodiment includes a first element unit 31 having a first element group 41 and a first inner member 42 that collectively constrains the first element group 41, a second element group 101, and a second inner member 102 that collectively constrains the second element group 101, and a second element unit 32 disposed adjacent to the first element unit 31 in the X direction, and an outer member 33 that collectively constrains the first element unit 31 and the second element unit 32 from the outside of the first inner member 42 and the second inner member 102. According to this configuration, by arranging a plurality of power storage elements 51, 105 in a plurality of rows in the X direction, the power storage device 1 can be downsized in the Z direction compared to the case where the power storage elements are arranged in a single row in the Z direction. Furthermore, by constraining the displacement of each element group 41, 101 in the Z direction with the corresponding inner members 42, 102, the expansion of each power storage element 51, 105 can be suppressed, and the characteristics of each power storage element 51, 105 can be maintained over a long period. In particular, by constraining each element group 41, 101 with separate inner members 42, 102, it is easy to constrain each element group 41, 101 while applying a desired pressure in the Z direction to each element group 41, 101. In addition, by collectively constraining each element unit 31, 32 with the outer member 33, the relative displacement of each element unit 31, 32 can be restricted. As a result, compared to a configuration in which the first unit and the second unit are simply arranged side by side while being independently fixed as in the prior art, the vibration resistance or shock resistance can be improved. In this case, it is difficult for a dimensional error in the Z direction to occur between the respective element groups 41, 101. As a result, even when a third connection bus bar 131c is provided across each element unit 31, 32, the load applied to the electrical connection portion such as the third connection bus bar 131c is reduced. Therefore, the power storage device 1 according to the present embodiment can provide a power storage device 1 that is excellent in reliability over a long period while achieving downsizing in the Z direction.

[0104] In the power storage device 1 of the present embodiment, the outer member 33 includes a first outer plate 120 disposed across only the portion facing the +Z side (the first side in the first direction) of the first inner member 42 and the second inner member 102, and a second outer plate 121 disposed across only the portion facing the -Z side (the second side in the first direction) of the first inner member 42 and the second inner member 102. According to this configuration, each of the outer plates 120 and 121 can restrain the relative displacement of each element unit 31 and 32 in the X direction, thereby improving the vibration resistance or shock resistance. Further, since the outer member 33 is disposed only at the portion facing the Z direction with respect to the element units 31 and 32, the power storage device 1 can be downsized in the X direction as compared with a configuration in which the outer member 33 surrounds the periphery of the element units 31 and 32.

[0105] In the power storage device 1 of the present embodiment, the first outer plate 120 is joined to the first inner member 42 and the second inner member 102 by a +Z side welding portion 126 extending in the Y direction, and the second outer plate 121 is joined to the first inner member 42 and the second inner member 102 by a -Z side welding portion 128 extending in the Y direction. According to this configuration, since each of the welding portions 126 and 128 extends in a direction intersecting the arrangement direction of each element unit 31 and 32, it is difficult for each of the welding portions 126 and 128 to straddle between each element unit 31 and 32. Therefore, the first inner member 42, the second inner member 102, and the outer member 33 can be stably joined. Further, since the inner members 42 and 102 and the outer member 33 are joined by welding, unlike a configuration in which the inner members 42 and 102 and the outer member 33 are fastened by screws or the like, it is not necessary to provide a fixing space (such as a flange portion) between the inner members 42 and 102 and the outer member 33. Therefore, the power storage module 11 can be downsized, and a small power storage device 1 can be provided.

[0106] The power storage device 1 of this embodiment includes a case 10 in which a first element unit 31 and a second element unit 32 are accommodated in a state of being constrained by an outer member 33. The outer member 33 is configured such that slits 120a and 121a are formed to engage with protrusions 21b and 22b formed on the case 10. According to this configuration, the assembling efficiency when assembling the power storage module 11 to the case 10 can be improved. Further, by forming the slits 120a and 121a in the outer member 33 itself, cost reduction can be achieved compared to the case where a separate member is provided for positioning between the power storage module 11 and the case 10. Note that the engagement by the protrusions 21b and 22b and the slits 120a and 121a may adopt a snap - fit structure. Further, the engagement between the case 10 and the outer member 33 may adopt means other than the engagement by the protrusions 21b and 22b and the slits 120a and 121a. A means may be adopted in which a concave portion is formed on one of the case 10 and the outer member 33, and a convex portion is formed on the other of the case 10 and the outer member 33.

[0107] In the power storage device 1 of this embodiment, the +X - side side portions 81b and 82b are joined in a state of overlapping each other on the +X - side (the first side in the second direction) with respect to the first element group 41, and the -X - side side portions 81c and 82c are joined in a state of overlapping each other on the -X - side (the second side in the second direction) with respect to the first element group 41. According to this configuration, by joining the corresponding +X - side side portions 81b and 82b and the -X - side side portions 81c and 82c to each other, the periphery of the first element group 41 is surrounded by the first inner member 42. In this case, the overlapping portions of the corresponding +X - side side portions 81b and 82b (+X - side overlapping portion 86) and the overlapping portions of the -X - side side portions 81c and 82c (-X - side overlapping portion 88) function as absorption margins for dimensional errors of the first element group 41 in the Z direction. Therefore, for example, compared to a configuration in which the periphery of the first element group 41 is surrounded by a cylindrical member in advance, the first element group 41 can be constrained in a state where a predetermined pressure is applied to the first element group 41 in the Z direction regardless of dimensional variations.

[0108] The power storage device 1 of this embodiment includes a +X side welding part 87 that joins the +X side parts 81b and 82b together, and a -X side welding part 89 that joins the -X side parts 81c and 82c together. The holder member 52 is configured to include peripheral wall parts 71b and 73b that overlap the welding parts 87 and 89 when viewed in the X direction. According to this configuration, since the peripheral wall parts 71b and 73b are arranged between the power storage elements 51 and the welding parts 87 and 89, it is possible to suppress the influence of heat generated during welding of the welding parts 87 and 89 from reaching the power storage elements 51.

[0109] In the power storage device 1 of this embodiment, the dimension in the Y direction in the first element group 41 is larger than the dimension in the Z direction in the first element group 41, and each of the welding parts 87 and 89 is configured to extend in the Y direction and be arranged at intervals in the Z direction. According to this configuration, for each of the welding parts 87 and 89, while ensuring the length per piece, the number of the welding parts 87 and 89 can be reduced. Therefore, the number of reciprocating scans of the welding machine can be reduced, and the manufacturing efficiency can be improved.

[0110] (Other modification examples) As described above, the preferred embodiments of the present disclosure have been described, but the present disclosure is not limited to these embodiments. Additions, omissions, substitutions, and other changes to the configuration are possible without departing from the spirit of the present disclosure. The present disclosure is not limited by the above description and is limited only by the appended claims. In the above-described embodiment, the case where the inner members 42 and 102 are each constituted by two restraint plates has been described, but the present disclosure is not limited to this configuration. The inner members 42 and 102 may be constituted by joining three or more restraint plates, or may be integrally formed in a cylindrical shape surrounding the corresponding element groups 41 and 101. In the above-described embodiments, the configuration in which the outer member 33 (the outer plate 120 and the second outer plate 121) is a flat plate provided only on both sides in the Z direction with respect to the element units 31 and 32 has been described. However, the configuration is not limited to this. The outer member 33 may be appropriately changed as long as it can restrict the relative displacement between the element units 31 and 32, such as a cylindrical shape that collectively surrounds the element units 31 and 32, a configuration provided only on one side in the Z direction with respect to the element units 31 and 32, or a configuration provided on one side or both sides in the Y direction with respect to the element units 31 and 32.

[0111] In the above-described embodiments, the configuration in which the power storage device 1 includes two rows of element units in the X direction has been described. However, the configuration is not limited to this. The element units may be provided in three or more rows in the X direction. In the above-described embodiments, the configuration in which the restraint plates of the inner members 42 and 102 or the inner members 42 and 102 and the outer member 33 are joined by laser welding has been described. However, the configuration is not limited to this. The restraint plates of the inner members 42 and 102 or the inner members 42 and 102 and the outer member 33 may be joined by welding other than laser welding (such as resistance welding or brazing) or adhesion, or may be fixed by various methods such as caulking or fastening. In the above-described embodiments, the configuration in which the +Z side welding portion 126 and the -Z side welding portion 128 extend in the Y direction has been described. However, the configuration is not limited to this. At least one of the +Z side welding portion 126 and the -Z side welding portion 128 may extend in the X direction, or may extend in a direction intersecting the X direction and the Y direction in the XY plane. Only one of the +Z side welding portion 126 and the -Z side welding portion 128 may be formed.

[0112] In the above-described embodiments, the power storage device 1 includes a case 10 in which the first element unit 31 and the second element unit 32 are accommodated in a state of being restrained by the outer member 33, and the outer member 33 is formed with slits 120a and 121a that engage with the protrusions 21b and 22b formed on the case 10. However, the configuration is not limited to this. The outer member 33 and the case 10 may not be provided with means for engaging with each other.

[0113] In the above-described embodiment, the power storage device 1 has been described in a configuration in which the +X side portions 81b and 82b are joined to each other in a state of overlapping each other on the +X side (the first side in the second direction) with respect to the first element group 41, and the -X side portions 81c and 82c are joined to each other in a state of overlapping each other on the -X side (the second side in the second direction) with respect to the first element group 41. However, the present invention is not limited to this configuration. At least one of the +X side portions 81b and 82b and the -X side portions 81c and 82c may not overlap in the X direction. Further, only one of the +X side portions 81b and 82b or the -X side portions 81c and 82c may be formed, or both may not be formed.

[0114] In the above-described embodiment, the power storage device 1 has been described in a configuration including a +X side welding portion 87 that joins the +X side portions 81b and 82b to each other and a -X side welding portion 89 that joins the -X side portions 81c and 82c to each other, and the holder member 52 includes peripheral wall portions 71b and 73b that overlap the respective welding portions 87 and 89 when viewed in the X direction. However, the present invention is not limited to this configuration. The holder member 52 may include peripheral wall portions corresponding to some of the welding portions, or may not include peripheral wall portions. The holder member 52 that does not include peripheral wall portions can also be referred to as a spacer disposed between the power storage elements. The power storage device 1 may not include the holder member 52.

[0115] In the above-described embodiment, the power storage device 1 has been described in a configuration in which the dimension of the first element group 41 in the Y direction is larger than the dimension of the first element group 41 in the Z direction, and each of the welding portions 87 and 89 extends in the Y direction and is arranged at intervals in the Z direction. However, the present invention is not limited to this configuration. The dimension of the first element group 41 in the Y direction may be smaller than the dimension of the first element group 41 in the Z direction. The respective welding portions 87 and 89 may not be spaced apart in the Z direction.

[0116] In addition, within the scope not departing from the gist of the present invention, it is possible to appropriately replace the components in the above-described embodiment with well-known components, and the above-described various modification examples may be appropriately combined.

Description of Symbols

[0117] 1: Power storage device 10: Case 21b: Base protrusion (positioning part) 22b: Cover protrusion (positioning part) 31: First element unit 32: Second element unit 33: Outer member 41: First element group 42: First inner member 51, 51A, 51B: First power storage element 52: First holder member (insulating member) 71b: Intermediate peripheral wall part (first extension part, second extension part) 73b: Second peripheral wall part (first extension part, second extension part) 81: First restraint plate 81a: First end part 81b: +X side side part (first side part) 81c: -X side side part (first side part) 82: Second restraint plate 82a, 111a: Second end part 82b: +X side side part (second side part) 82c: -X side side part (second side part) 87: +X side welding part (first inner welding part) 89: -X side welding part (second inner welding part) 101: Second element group 102: Second inner member 105, 105A, 105B: Second power storage element 106: Second holder member (insulating member) 110: First restraint plate 110a: First end part 110b: +X side side part (first side part) 110c: -X side side part (first side part) 111: Second restraint plate 111a: Second end part 111b: +X side side part (second side part) 111c: -X side portion (second side portion) 120: First outer plate 120a: First slit (engagement portion) 121: Second outer plate 121a: Second slit (engagement portion)

Claims

1. A first element unit having a first element group in which first power storage elements are arranged in a first direction, and a first inner member that constrains the first element group in the first direction; A second element unit having a second element group in which second power storage elements are arranged in the first direction, and a second inner member that is provided separately from the first inner member and constrains the second element group in the first direction, and is arranged adjacent to the first element unit in a second direction intersecting the first direction; An outer member that collectively constrains the first element unit and the second element unit from the outside of the first inner member and the second inner member. A power storage device.

2. The outer member is: A first outer plate disposed across only a portion facing the first side in the first direction of the first inner member and the second inner member; A second outer plate disposed across only a portion facing the second side in the first direction of the first inner member and the second inner member. The power storage device according to claim 1.

3. The first outer plate is joined to the first inner member and the second inner member by a first outer welding portion extending in a third direction intersecting the second direction when viewed from the first direction; The second outer plate is joined to the first inner member and the second inner member by a second outer welding portion extending in the third direction. The power storage device according to claim 2.

4. A case for housing the first element unit and the second element unit in a state of being constrained by the outer member; An engaging portion that engages with a positioning portion formed on the case is formed on the outer member. The power storage device according to any one of claims 1 to 3.

5. The first inner member is: A first constraint plate having a first end portion disposed on the first side in the first direction with respect to the first element group, and a first side portion extending from both end portions in the second direction of the first end portion to the second side in the first direction; A second constraint plate having a second end portion disposed on the second side in the first direction with respect to the first element group, and a second side portion extending from both end portions in the second direction of the second end portion to the first side in the first direction. One of the first side portion and one of the second side portion are joined in a state of overlapping each other on the first side in the second direction with respect to the first element group. The other said first side portion and the other said second side portion are joined in a state of overlapping each other on the second side in the second direction with respect to the first element group. The power storage device according to any one of claims 1 to 3.

6. The first element unit includes a first inner welding portion that joins the one first side portion and the one second side portion, a second inner welding portion that joins the other first side portion and the other second side portion, an insulating member that is disposed between the first element group and the first inner member and insulates between the first element group and the first inner member. The insulating member includes a first extension portion that overlaps the first inner welding portion when viewed from the second direction within the first inner member, a second extension portion that overlaps the second inner welding portion when viewed from the second direction within the first inner member. The power storage device according to claim 5.

7. The dimension in the third direction that intersects the second direction when viewed from the first direction in the first element group is larger than the dimension in the first direction in the first element group, Each of the first inner welding portion and the second inner welding portion extends in the third direction and is arranged at intervals in the first direction. The power storage device according to claim 6.

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