Electrical storage element and electrical storage device

Abstract

An electrical storage element according to one embodiment of the present invention is characterized by comprising an electrode body which has a plurality of electrode sheets laminated therein, a container that accommodates the electrode body, and a pair of electrode terminals that are electrically connected to the electrode body. The electrical storage element is further characterized in that: the container is formed in a rectangular shape which, as viewed in a first direction being a predetermined horizontal direction, is long in a second direction that is horizontal and orthogonal to the first direction, and which has a cutout shape at two corners, among the four corners thereof, on at least one side in the vertical direction; each cutout shape is formed of a first surface that, as viewed in the first direction, extends from the short side of the rectangular shape toward the center of the rectangular shape in the second direction, and a second surface that extends from a leading-end side of the first surface toward the long side, of the rectangular shape, on one side in the vertical direction; and each electrode terminal is formed in an L-figure shape extending along the first surface and the second surface.

Description

Energy storage element and energy storage device

[0001] The present invention relates to an energy storage element and an energy storage device including a plurality of energy storage elements.

[0002] 2. Description of the Related Art Conventionally, a non-aqueous electrolyte secondary battery 500 including an outer can 501 that houses an electrode winding body, as shown in FIG. 9, has been known (see Patent Document 1).

[0003] In this nonaqueous electrolyte secondary battery 500, an outer can 501 has a rectangular shape with one of the four corners cut away (a notched shape) when viewed from a predetermined direction, and a positive electrode terminal 502 is disposed on a surface 504 perpendicular to the height direction of a main body 503. This positive electrode terminal 502 extends along the surface 504.

[0004] In such a nonaqueous electrolyte secondary battery 500, if a bus bar is welded to the positive electrode terminal 502 when connecting a plurality of secondary batteries in series or in parallel, it may not be possible to ensure a sufficient area for the contact surface or welding surface at the connection portion (weld interface) between the positive electrode terminal 502 and the bus bar, and heat may be generated at the connection portion.

[0005] JP 2015-185254 A

[0006] Therefore, an object of this embodiment is to provide an energy storage element that can ensure a sufficient area for the connection portion between the electrode terminal and the bus bar, and an energy storage device including this energy storage element.

[0007] The energy storage element of this embodiment comprises an electrode body formed by stacking a plurality of electrode plates; a container that houses the electrode body; and a pair of electrode terminals that are electrically connected to the electrode body. When viewed from a first direction, which is a predetermined horizontal direction, the container has a rectangular shape that is elongated in a second horizontal direction that is perpendicular to the first direction, and has notched shapes at least two of the four corners of the rectangle on one side in the vertical direction. When viewed from the first direction, each notched shape is composed of a first surface that extends from a short side of the rectangle toward the center of the rectangle in the second direction, and a second surface that extends from the tip of the first surface toward the long side of the rectangle on one side in the vertical direction. When viewed from the first direction, each electrode terminal is L-shaped along the first surface and the second surface.

[0008] Furthermore, the energy storage device of this embodiment includes the above-mentioned energy storage elements arranged in the first direction, and at least one electrically conductive bus bar, which extends in the first direction so as to be able to connect the corresponding electrode terminals of at least adjacent energy storage elements, and which is L-shaped along the electrode terminals when viewed from the first direction.

[0009] As described above, according to this embodiment, it is possible to provide an energy storage element that can ensure a sufficient area for the connection portion between the electrode terminal and the bus bar, and an energy storage device that includes this energy storage element.

[0010] FIG. 1 is a perspective view of an energy storage device according to the present embodiment. FIG. 2 is an exploded perspective view of the energy storage device. FIG. 3 is a perspective view of an energy storage element included in the energy storage device. FIG. 4 is an exploded perspective view of the energy storage element. FIG. 5 is a diagram for explaining the configuration of an electrode body included in the energy storage element. FIG. 6 is a view of the energy storage element with the middle omitted. FIG. 7 is a vertical cross-sectional view of the energy storage device with the middle omitted. FIG. 8 is a perspective view of an energy storage element according to another embodiment. FIG. 9 is a perspective view of a conventional non-aqueous electrolyte secondary battery.

[0011] (1) An energy storage element according to one embodiment of the present invention comprises: an electrode body formed by stacking a plurality of electrode plates; a container for accommodating the electrode body; and a pair of electrode terminals connected to the electrode body; wherein the container has a rectangular shape, when viewed from a first direction which is a predetermined horizontal direction, that is orthogonal to the first direction and elongated in a second horizontal direction, and has notched shapes at least in two corners on one side in the vertical direction out of four corners of the rectangle; each notched shape is constituted by a first surface extending from a short side of the rectangle toward the center of the rectangle in the second direction when viewed from the first direction, and a second surface extending from an end of the first surface toward one long side of the rectangle in the vertical direction; and each electrode terminal has an L-shape along the first surface and the second surface when viewed from the first direction.

[0012] In the energy storage element according to one embodiment of the present invention, since the electrode terminals are L-shaped when viewed from the first direction, when the bus bars are connected to the electrode terminals, they are connected to portions on both sides of the bent portion of the electrode terminal, thereby ensuring a sufficient area for the connection portion between the electrode terminal and the bus bar. Note that in this embodiment, the method for stacking the electrode plates in the electrode body may be a method of stacking multiple sheet-like electrode plates, or a method of stacking strip-like electrode plates (positive electrode plates and negative electrode plates) by winding them.

[0013] (2) The energy storage element described in (1) above may include a pair of insulating portions that electrically insulate the container from the electrode terminal, and each insulating portion may be located between the container and the electrode terminal and may be L-shaped when viewed from the first direction.

[0014] According to the energy storage element described in (2) above, insulating portions are located between the first surface of the container and the portion along the first surface of the electrode terminal, and between the second surface of the container and the portion along the second surface of the electrode terminal, thereby providing sufficient insulation between the container and the electrode terminal.

[0015] (3) In the energy storage element described in (1) above, a first portion of the electrode terminal along the first surface may be located within a projection area of ​​the first surface in the vertical direction, and a second portion of the electrode terminal along the second surface may be located within a projection area of ​​the second surface in the second direction.

[0016] According to the energy storage element described in (3) above, when a plurality of energy storage elements are arranged in the first direction, contact between the first portions and the second portions of adjacent energy storage elements is suppressed. Also, when a plurality of energy storage elements are arranged in the first direction, protrusion of the electrode terminals from one edge position of each energy storage element in the up-down direction and from both edge positions of each energy storage element in the second direction is suppressed when viewed from the first direction.

[0017] (4) An energy storage device according to one embodiment of the present invention includes: a plurality of energy storage elements according to any one of (1) to (3) arranged in the first direction; and at least one electrically conductive bus bar, wherein the bus bar extends in the first direction so as to be able to connect corresponding electrode terminals of at least adjacent energy storage elements to each other, and has an L-shape along the electrode terminals when viewed from the first direction.

[0018] According to the energy storage device described in (4) above, the L-shaped electrode terminal of the energy storage element has two portions sandwiching a bent portion. Therefore, when the bus bar connects corresponding electrode terminals of at least adjacent energy storage elements, the bus bar is connected to each of the two portions of the electrode terminal, thereby ensuring a sufficient area for the connection portion between the electrode terminal and the bus bar.

[0019] (5) The energy storage device described in (4) above includes an element container in which at least one of a plurality of inner surfaces defining an internal storage space is a cooling surface, and the element container may house the plurality of energy storage elements and the energy storage element group so that the energy storage elements and the energy storage element group are in contact with the cooling surface.

[0020] According to the energy storage device described in (5) above, the energy storage elements housed in the element container are cooled by being in contact with the cooling surface, and therefore, a temperature rise of the energy storage elements during charging and discharging is suppressed.

[0021] (6) In the energy storage device described in (5) above, the bus bar may be located within a projection area of ​​the first surface in the vertical direction and within a projection area of ​​the second surface in the second direction, as viewed from the first direction.

[0022] According to the energy storage device described in (6) above, the bus bars do not protrude outward in the second direction or to one side in the vertical direction when viewed from the first direction in the energy storage element group, thereby preventing the occurrence of dead space within the storage space due to the protrusion of the bus bars (see, for example, Figure 7).

[0023] An embodiment of the present invention will be described below with reference to Figures 1 to 7. Note that the names of the components in this embodiment are those used in this embodiment and may differ from the names of the components in the background art.

[0024] In the following description and drawings, the longitudinal direction of the energy storage element and the direction along the winding axis of the electrode body provided in the energy storage element are defined as the X-axis direction (second direction). The arrangement direction of the multiple energy storage elements and the thickness direction of the container of the energy storage element are defined as the Y-axis direction (first direction). The arrangement direction of the case lid and case body of the energy storage device, the arrangement direction of the bottom surface of the container body and the top surface of the lid, or the up-down direction are defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). In the following description, the term "insulation" means "electrical insulation." In this embodiment, for example, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions.

[0025] An electric storage device is a device that can charge electricity from an external source and discharge electricity to an external source. The electric storage device 1 of this embodiment has a substantially rectangular parallelepiped shape as shown in FIG. 1 . The electric storage device 1 is a battery module (battery assembly) used for power storage or power supply purposes, and is used, for example, as a battery for driving or starting the engine of a moving object such as an automobile, motorcycle, personal watercraft, boat, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, an automatic guided vehicle (AGV), and a hybrid electric train 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.

[0026] 2 and 3 , the energy storage device 1 includes an energy storage element group 3 including a plurality of energy storage elements 10 and at least one (a plurality in this embodiment) bus bar 30, and a case portion (element container) 2 that houses the energy storage element group 3. In addition to the above-mentioned components, the energy storage device 1 may also include restraining members (end plates, side plates, etc.) that restrain the plurality of energy storage elements 10, a bus bar holder that holds the bus bar 30, a bus bar cover, a circuit board that monitors or controls the charge state and discharge state of the energy storage elements 10, and electrical components such as a relay, a fuse, a shunt resistor, and a connector.

[0027] The case portion 2 has a case 20 having an accommodation space S therein, and a refrigerant pipe 26 for cooling the energy storage element group 3 via the case 20 .

[0028] The case 20 is a substantially rectangular parallelepiped (box-shaped) container (module case) that constitutes the exterior body (housing, outer shell) of the energy storage device 1, and the storage space S is also rectangular or substantially rectangular. That is, the case 20 has six (plural) inner surfaces 20S that define the storage space S, and each inner surface 20S is a flat, rectangular surface.

[0029] This case 20 accommodates the energy storage element group 3 in the accommodation space S, thereby fixing (holding) the energy storage element group 3 etc. in a predetermined position, thereby protecting each energy storage element 10 included in the energy storage element group 3 from impact, vibration, etc. In the case 20 of this embodiment, after each energy storage element 10 is compressed and accommodated in the case 20, each energy storage element 10 is fixed in the case 20 by the restoring force of the energy storage element 10.

[0030] The case 20 is a metal case formed from a metal member such as aluminum, aluminum alloy, stainless steel, iron, or plated steel sheet. Therefore, the case 20 can efficiently dissipate heat from each energy storage element 10 to the outside of the case 20, and can suppress or cool each energy storage element 10. If the case 20 is conductive, the inner surface of the case 20 may be coated with an insulating material to ensure insulation from the energy storage element group 3. The case 20 is not limited to being made of metal, and may be made of resin, etc.

[0031] Case 20 of this embodiment has case body 21 which has opening 21A and constitutes the main body of case 20, and case lid 25 which closes opening 21A. In addition, in case 20 of this embodiment, case body 21 and case lid 25 are made of the same material, but they may also be made of different materials.

[0032] The case body 21 is a rectangular cylinder with a bottom and has an opening 21A on the positive side in the Z-axis direction (upper side in FIG. 2), and accommodates the energy storage element group 3 and the like.

[0033] Specifically, the case body 21 has a plate-shaped bottom wall 22 that extends in a plane direction perpendicular to the Z-axis direction, and a peripheral wall 23 that extends from the peripheral edge of the bottom wall 22 to the positive side of the Z-axis direction. In this embodiment, the bottom wall 22 is rectangular, and the peripheral wall 23 is square-tube.

[0034] The peripheral wall 23 is configured by four rectangular plate-shaped side walls (a first side wall 231, a second side wall 232, a third side wall 233, and a fourth side wall 234) that are continuously arranged in the circumferential direction along the peripheral edge of the bottom wall 22. In the peripheral wall 23 of this embodiment, the first side wall 231 has a first general terminal 235, and the third side wall 233 has a second general terminal 236. The positions of the general terminals on the peripheral wall 23 are not limited. That is, the positions of the general terminals on the peripheral wall 23 vary depending on the terminal positions of the energy storage elements 10, the number of energy storage elements 10 arranged in the case 20 (number of stacks), the series / parallel relationship of the energy storage elements 10 and the energy storage element group 3 in the case 20, etc.

[0035] The first general terminal 235 is a terminal for inputting electricity from outside the case 20 to the energy storage element group 3 housed in the case 20, or for outputting electricity from the energy storage element group 3 to the outside of the case 20. In this embodiment, the first general terminal 235 is disposed at the end of the first side wall 231 on the negative side in the X-axis direction (the left side in FIG. 2 ) and on the positive side in the Z-axis direction.

[0036] The second general terminal 236 is a terminal for outputting electricity from the energy storage element group 3 housed in the case 20 to the outside of the case 20, or for inputting electricity from the outside of the case 20 to the energy storage element group 3. In this embodiment, the second general terminal 236 is disposed at the end of the third side wall 233 on the positive side in the X-axis direction (the right side in FIG. 2 ) and on the positive side in the Z-axis direction.

[0037] The case cover 25 is a portion or member that closes the rectangular opening 21A of the case body 21, and is a rectangular plate that extends along the XY plane.

[0038] In the case 20 of this embodiment, the case body 21 and the case lid 25 configured as described above are joined by welding, melting, screwing, or the like, thereby sealing the storage space S.

[0039] The refrigerant pipe 26 cools the energy storage element group 3 via the case 20 by circulating a refrigerant such as a gas or fluid therethrough, and in this embodiment, the refrigerant pipe 26 is arranged on the outer surface of the case 20 (not shown in FIG. 2 ). The refrigerant pipe 26 is joined to the case 20 by welding. In this embodiment, the refrigerant pipe 26 is arranged in a bellows shape on each outer surface of two side walls (the second side wall 232 and the fourth side wall 234) facing each other in the X-axis direction, on the lower surface of the bottom wall 22, and on the upper surface of the case lid 25. The refrigerant flows through the refrigerant pipe 26, thereby cooling the case 20 (the portion where the refrigerant pipe 26 is arranged), and thereby a portion of the inner surface 20S of the case 20 can be made into a cooling surface 20CS.

[0040] The cooling surface 20CS is a surface that can cool the energy storage element group 3 (more specifically, each energy storage element 10) by coming into contact with the energy storage element group 3 (more specifically, each energy storage element 10) housed in the housing space S of the case 20 (see FIG. 8 ), and in the case 20 of this embodiment, the second side wall 232, the fourth side wall 234, the bottom wall 22, and the case lid 25 are cooled by refrigerant pipes 26 through which a refrigerant flows, and the inner surfaces 20S of these walls 232, 234, 22, and 25 each constitute a cooling surface 20CS. That is, the case 20 of this embodiment has four cooling surfaces 20CS.

[0041] The energy storage element group 3 includes a plurality of energy storage elements 10 arranged in the Y-axis direction, each having a pair of electrode terminals 140 (a positive terminal 140A and a negative terminal 140B), and a plurality of bus bars 30 that connect (conduct) corresponding electrode terminals 140 of at least adjacent energy storage elements 10. In the energy storage element group 3 of this embodiment, the plurality of energy storage elements 10 are arranged in the Y-axis direction such that corresponding electrode terminals (more specifically, electrode terminals 140 connected by bus bars 30) of adjacent energy storage elements 10 have mutually different polarities (i.e., the positive terminal 140A and the negative terminal 140B are adjacent to each other in the Y-axis direction). As a result, the energy storage elements 10 of the energy storage element group 3 are connected in series to each other.

[0042] The energy storage element 10 charges with electricity from an external source and discharges electricity to the external source. The energy storage element 10 of this embodiment is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery, but is not limited thereto. It may be a secondary battery other than a non-aqueous electrolyte secondary battery, or a capacitor. The energy storage element 10 may also be a primary battery that can use stored electricity without the user having to charge it, instead of a secondary battery. The energy storage element 10 may also be, for example, an all-solid-state lithium battery using a solid electrolyte, or a polymer lithium battery. The energy storage element 10 may also be a pouch-type energy storage element. The energy storage element 10 of this embodiment has a generally rectangular parallelepiped shape that is elongated in the X-axis direction. However, the shape of the energy storage element 10 is not limited to a generally rectangular parallelepiped shape, and may be a polygonal prism, an elongated cylinder, an elliptical cylinder, a cylindrical shape, or the like.

[0043] The energy storage element 10 of this embodiment has a shape in which the dimension in the X-axis direction is larger than the dimension in the Y-axis direction, specifically, a rectangular parallelepiped shape (square, rectangular) that is flat in the Y-axis direction and elongated in the X-axis direction. As shown in FIGS. 3 to 6 , this energy storage element 10 includes an electrode assembly 110 in which multiple electrode plates 113, 114 are stacked, a container 120 that houses the electrode assembly 110, and a pair of electrode terminals 140 that are electrically connected to the electrode assembly 110. The energy storage element 10 also includes a pair of external gaskets (insulating portions) 150 on the outside of the container 120. The energy storage element 10 also includes a pair of internal gaskets 160 and a pair of current collectors 170 inside the container 120.

[0044] The electrode body 110 is a storage element (power generating element) capable of storing electricity, and is formed by winding a plurality of electrode plates 113, 114 in a stacked state. The electrode body 110 of this embodiment has an elongated shape in the X-axis direction and an oval shape (racetrack shape) when viewed from the X-axis direction. The electrode body 110 has a larger dimension in the X-axis direction than in the Z-axis direction. The dimension of the electrode body 110 of this embodiment in the X-axis direction is, for example, 300 mm or more, specifically, approximately 500 mm to 1500 mm. Furthermore, the electrode body 110 of this embodiment has, for example, a dimension in the X-axis direction that is three times or more the dimension in the Z-axis direction. Specifically, the electrode body 110 has a main body portion 111 and a plurality of tab portions 112 protruding from the main body portion 111.

[0045] The multiple tab portions 112 are portions (connections) of the electrode body 110 that are connected (joined) to the current collector 170, and in the electrode body 110 of this embodiment, one tab portion 112 protrudes from each of both ends of the main body portion 111 in the X-axis direction. That is, the electrode body 110 has two tab portions 112. For example, a positive electrode tab portion 112a is disposed at the end of the main body portion 111 on the positive side in the X-axis direction, and a negative electrode tab portion 112b is disposed at the end of the main body portion 111 on the negative side in the X-axis direction. Note that the tab portions 112 shown in FIGS. 4 and 5 are an example of connections that are connected to the current collector 170, and the present invention is not limited to this configuration.

[0046] Specifically, the electrode assembly 110 includes a positive electrode plate 113 , a negative electrode plate 114 , and separators 115 and 116 .

[0047] The positive electrode plate 113 has a positive electrode current collector foil 1131 which is a long strip of metal foil, and positive electrode active material layers 1132 which are disposed on both sides of the positive electrode current collector foil 1131 .

[0048] The positive electrode current collector foil 1131 is made of aluminum or an aluminum alloy. The positive electrode active material constituting the positive electrode active material layer 1132 is LiMPO ４ , LiMSiO ４ , LiMBO ３(M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), polyanion compounds such as lithium titanate, LiMn ２ O ４ and LiMn １．５ Ni ０．５ O ４ Spinel-type lithium manganese oxides such as α-NaFeO ２ LiMO having a type crystal structure ２ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) As the positive electrode active material used in the positive electrode active material layer 1132, any known material can be used as long as it is capable of absorbing and releasing charge transport ions.

[0049] Furthermore, a plurality of protruding pieces 1133 protruding outward are arranged at intervals on the edge on the positive side in the X-axis direction of the positive electrode plate 113. Each protruding piece 1133 is a portion where no positive electrode active material layer is disposed and the positive electrode current collector foil 1131 is exposed (a portion where no positive electrode active material layer is formed), and is a portion indicated by hatching in Fig. 5 .

[0050] The negative electrode plate 114 has a negative electrode current collector foil 1141 which is a long strip of metal foil, and negative electrode active material layers 1142 which are disposed on both sides of the negative electrode current collector foil 1141 .

[0051] The negative electrode current collector foil 1141 is made of copper or a copper alloy, etc. The negative electrode active material constituting the negative electrode active material layer 1142 is lithium metal, an alloy capable of absorbing and desorbing lithium, a carbon material (graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), silicon oxide, etc. Any known material can be used as the negative electrode active material used in the negative electrode active material layer 1142 as long as it is capable of absorbing and desorbing charge transport ions.

[0052] Furthermore, a plurality of protruding pieces 1143 protruding outward are arranged at intervals on the edge on the negative side in the X-axis direction of the negative electrode plate 114. Each protruding piece 1143 is a portion where no negative electrode active material layer is disposed and the negative electrode current collector foil 1141 is exposed (negative electrode active material layer non-formed portion), and is a portion indicated by hatching in Fig. 5 .

[0053] The separators 115, 116 are microporous sheets made of resin. Any known material can be used as the material for the separators 115, 116 as long as it does not impair the performance of the energy storage device 10. For example, the separators 115, 116 are woven fabric or nonwoven fabric that is insoluble in organic solvents, or a synthetic resin microporous film made of a polyolefin resin such as polyethylene.

[0054] The electrode assembly 110 is formed by winding the positive electrode plate 113, the negative electrode plate 114, and the separators 115 and 116 configured as described above in a stacked state. In the electrode assembly 110 of this embodiment, the positive electrode plate 113, the negative electrode plate 114, and the separators 115 and 116 are wound around a winding axis L extending in the X-axis direction using a winding core having an oval cross section (racetrack shape), thereby forming the wound electrode assembly 110. The winding axis L is a virtual axis that serves as the central axis when winding the positive electrode plate 113, the negative electrode plate 114, and the separators 115 and 116, and in this embodiment, the winding axis L is a straight line that passes through the center of the electrode assembly 110 and is parallel to the X-axis direction (see FIG. 5 ).

[0055] Furthermore, by winding the positive electrode plate 113, the negative electrode plate 114, and the separators 115 and 116 in a stacked state in order, the multiple protruding pieces 1133 of the positive electrode plate 113 overlap at the positive end of the main body 111 in the X-axis direction, and the multiple protruding pieces 1143 of the negative electrode plate 114 overlap at the negative end of the main body 111 in the X-axis direction.

[0056] In the electrode body 110, the positive electrode tab portion 112a is a portion where the multiple protruding pieces 1133 of the positive electrode plate 113 overlap. That is, the positive electrode tab portion 112a is a portion where the multiple pieces (protruding pieces 1133) provided on the electrode plate (positive electrode plate 113) of the same polarity among the multiple electrode plates (positive electrode plate 113 and negative electrode plate 114) are stacked.

[0057] Similarly, in the electrode body 110, the portion where the multiple protruding pieces 1143 of the negative electrode plate 114 overlap is the negative electrode tab portion 112b. That is, the negative electrode tab portion 112b is a portion where multiple pieces (protruding pieces 1143) provided on the electrode plate (negative electrode plate 114) of the same polarity among the multiple electrode plates (positive electrode plate 113 and negative electrode plate 114) are stacked.

[0058] As described above, the electrode body 110 has a main body portion 111 that constitutes the main body of the electrode body 110, and tab portions 112 (positive electrode tab portion 112a and negative electrode tab portion 112b) that protrude from each end portion in the X-axis direction of the main body portion 111. That is, the electrode body 110 has a pair of tab portions 112 that are constituted by the positive electrode tab portion 112a and the negative electrode tab portion 112b.

[0059] The main body portion 111 is an elongated cylindrical portion formed by winding together a portion of the positive electrode plate 113 where the positive electrode active material layer 1132 is disposed (formed, coated), a portion of the negative electrode plate 114 where the negative electrode active material layer 1142 is disposed (formed, coated), and separators 115 and 116. In the main body portion 111, the region where at least one of the positive electrode active material layer 1132 and the negative electrode active material layer 1142 is laminated is referred to as an active material layer formation portion. Furthermore, because the main body portion 111 has an elongated cylindrical shape, the outer surface (outer peripheral surface) of the main body portion 111 has curved portions 1111 at both ends in the Z-axis direction and flat portions 1112 at both ends in the Y-axis direction.

[0060] Curved portion 1111 is a surface that extends in the X-axis direction and is curved so as to be convex outward in the Z-axis direction (the side away from winding axis L). In this embodiment, curved portion 1111 is curved in a semicircular arc shape when viewed in the X-axis direction.

[0061] The flat portion 1112 is a flat surface extending in the X-axis direction and along the XZ plane connecting the ends of the pair of curved portions 1111. In a portion of the main body 111 corresponding to the flat portion 1112 (more specifically, a portion sandwiched between the pair of flat portions 1112 in the Y-axis direction), a plurality of electrode plates and separators (positive electrode plate 113, negative electrode plate 114, separators 115, 116) are stacked in the Y-axis direction.

[0062] The shape of the electrode body 110 is not limited to a wound type, but may be a stack type in which flat electrode plates are stacked, or a shape in which at least one of the electrode plates and the separator is folded accordion-like (a form in which the separator is folded accordion-like and a rectangular electrode plate is sandwiched between it, a form in which the electrode plate and the separator are stacked and folded accordion-like, etc.).

[0063] The container 120 containing the electrode body 110 configured as described above has a rectangular shape that is elongated in the X-axis direction (a horizontal direction perpendicular to the Y-axis direction) when viewed from the Y-axis direction (a predetermined horizontal direction), and has notches (notches 131, 132) at least in two of the four corners of the rectangle on the positive side in the Z-axis direction. These notch shapes at the two corners on the positive side in the Z-axis direction are composed of a first upper surface (first surface) 1212 or a second upper surface (first surface) 1222 that extends from a short side of the rectangle toward the inside of the rectangle in the X-axis direction when viewed from the Y-axis direction, and a first upper side surface (second surface) 1211 or a second upper side surface (second surface) 1221 that extends from the tip of the first upper surface 1212 or the second upper surface 1222 toward the long side of the rectangle on the positive side in the Z-axis direction.

[0064] Specifically, the container 120 has an outer shape (approximately rectangular parallelepiped shape) based on a rectangular parallelepiped shape that is long in the X-axis direction and flat in the Y-axis direction. For example, the dimension of the container 120 in the X-axis direction is three or more times the dimension in the Z-axis direction. In Figures 3 and 6, the rectangular parallelepiped shape that serves as the basis is illustrated by a two-dot chain line L1.

[0065] The container 120 of this embodiment has an outer shape that is long and flat in the X-axis direction, with rectangular notches formed at the upper end of each end in the X-axis direction (the end on the positive side in the Z-axis direction). Furthermore, at the end on the positive side in the Z-axis direction of the container 120, notches 131 and 132 are spaced apart in the X-axis direction. Electrode terminals 140 are disposed in these notches 131 and 132, respectively.

[0066] Specifically, the first side end surface portion 121 is the end surface on the positive side in the X-axis direction of the container 120, and has a first upper side surface (second surface) 1211, a first top surface (first surface) 1212, and a first side surface 1213, and is elongated in the Z-axis direction when viewed from the X-axis direction.

[0067] The first upper side surface 1211 is disposed at the upper end (the end on the positive side in the Z-axis direction) of the first side end surface portion 121, and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction. The first upper surface 1212 is a plane extending from the lower end of the first upper side surface 1211 to the positive side in the X-axis direction, and is a rectangular plane parallel to the XY plane and elongated in the X-axis direction. The first side surface 1213 is a plane extending downward from the end on the positive side in the X-axis direction of the first upper surface 1212, and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction.

[0068] The cutout portion 131 of the first side end surface portion 121 is formed by a first upper side surface 1211 and a first top surface 1212. In this manner, the surface constituting the cutout portion 131 of the first side end surface portion 121 includes the first upper side surface 1211 and the first top surface 1212 that extend in different directions (in the example of this embodiment, the positive side in the Z-axis direction and the positive side in the X-axis direction) when viewed from the Y-axis direction.

[0069] In other words, the notch portion 131 of the first side end face portion 121 has a notch shape in which the corner (corner portion) on the positive side in the X-axis direction and the positive side in the Z-axis direction of the container 120 is recessed (cut out) into a square shape (L-shape) when viewed from the Y-axis direction.

[0070] In addition, the second side end surface portion 122 is the end surface on the negative side in the X-axis direction of the container 120, and has a second upper side surface (second surface) 1221, a second upper surface (first surface) 1222, and a second side surface 1223, and is elongated in the Z-axis direction when viewed from the X-axis direction.

[0071] The second upper side surface 1221 is located at the upper end (the end on the positive side in the Z-axis direction) of the second side end surface portion 122 and is a rectangular plane parallel to the YZ plane and elongated in the Z-axis direction. The second upper surface 1222 is a plane extending from the lower end of the second upper side surface 1221 to the negative side in the X-axis direction and is a rectangular plane parallel to the XY plane and elongated in the X-axis direction. The second side surface 1223 is a plane extending downward from the end of the second upper surface 1222 on the negative side in the X-axis direction. In the container 120 of this embodiment, the second upper side surface 1221 has the same shape and size as the first upper side surface 1211, the second upper surface 1222 has the same shape and size as the first upper surface 1212, and the second side surface 1223 has the same shape and size as the first side surface 1213.

[0072] The notch 132 of the second side end surface portion 122 is formed by the second upper side surface 1221 and the second top surface 1222. In this manner, the surface constituting the notch 132 of the second side end surface portion 122 includes the second upper side surface 1221 and the second top surface 1222 that extend in different directions (in the example of this embodiment, the positive side in the Z axis direction and the negative side in the X axis direction) when viewed from the Y axis direction.

[0073] In other words, the notch portion 132 of the second side end face portion 122 has a notch shape in which the corner (corner portion) on the negative side in the X-axis direction and the positive side in the Z-axis direction of the container 120 is recessed (cut out) into a square shape (L-shape) when viewed from the Y-axis direction.

[0074] In addition, in this container 120, both end faces opposing each other in the Y-axis direction are long side faces 123. Each long side face 123 is a flat surface that is parallel to the XZ plane and elongated in the X-axis direction, and both end portions in the X-axis direction have shapes corresponding to the first side end face portion 121 and the second side end face portion 122.

[0075] Of the two end faces of the container 120 in the Z-axis direction, the end face on the positive side in the Z-axis direction is a top surface 124 , and the end face on the negative side in the Z-axis direction is a bottom surface 125 .

[0076] The top surface 124 is a rectangular flat surface parallel to the XY plane and elongated in the X-axis direction, connecting the upper end of the first upper side surface 1211 of the first side end surface portion 121 and the upper end of the second upper side surface 1221 of the second side end surface portion 122. The bottom surface 125 is a rectangular flat surface parallel to the XY plane and elongated in the X-axis direction, connecting the lower end of the first side surface 1213 of the first side end surface portion 121 and the lower end of the second side surface 1223 of the second side end surface portion 122.

[0077] The container 120 having the above-described surfaces 121, 122, 124, and 125 includes a container body 135 and a lid 136. The lid 136 is attached to the container body 135 to form a generally rectangular parallelepiped shape. The container body 135 has a pair of long sides 123 and a bottom surface 125. The lid 136 has a first side end surface 121 (i.e., a first upper side surface 1211, a first top surface 1212, and a first side surface 1213), a second side end surface 122 (i.e., a second upper side surface 1221, a second top surface 1222, and a second side surface 1223), and a top surface 124. In this embodiment, the surface (outer surface) of the container 120 is covered with an insulating member such as an insulating film to ensure insulation from adjacent energy storage elements 10 in the energy storage element group 3.

[0078] Specifically, the container body 135 is a generally U-shaped plate-like member that is open at the top when viewed in the X-axis direction. The container body 135 has flat long side wall portions with long sides 123 at both ends in the Y-axis direction, and a rectangular plate-like bottom wall portion with a bottom surface 125 at the end on the negative side in the Z-axis direction.

[0079] The lid 136 is a strip-shaped member that is open downward when viewed in the Y-axis direction. The lid 136 of this embodiment is formed by bending a strip-shaped member into a predetermined shape. Specifically, the lid 136 has a bent plate portion at its end on the positive side in the X-axis direction, which has a first upper side surface 1211, a first top surface 1212, and a first side surface 1213, and a bent plate portion at its end on the negative side in the X-axis direction, which has a second upper side surface 1221, a second top surface 1222, and a second side surface 1223. The lid 136 also has a rectangular plate-shaped top wall portion with a top surface 124 at its end on the positive side in the Z-axis direction.

[0080] With this configuration, the container 120 is structured so that after the electrode body 110 and the like are accommodated inside the container body 135, the container body 135 and the lid body 136 are joined by welding or the like, thereby sealing the interior (accommodation space S).

[0081] In this container 120, the dimension in the X-axis direction between the top wall and the bottom wall is the same as or approximately the same as the dimension in the X-axis direction of the main body 111 of the electrode body 110, and the distance in the Z-axis direction between the top wall and the bottom wall is the same as or approximately the same as the dimension in the Z-axis direction of the main body 111 of the electrode body 110. That is, in the electrode body 110 accommodated in the container 120 (more specifically, within the accommodation space S of the container 120), the positive end of the main body 111 in the Z-axis direction abuts against the top wall of the container 120, and the negative end of the main body 111 in the Z-axis direction abuts against the bottom wall of the container 120. Furthermore, in the electrode body 110 accommodated in the container 120, the positive end of the main body 111 in the X-axis direction (more specifically, the positive end of the end in the Z-axis direction) abuts against a portion corresponding to the first upper side surface 1211 of the bent plate portion of the lid body 136 on the positive side in the X-axis direction, and the negative end of the main body 111 in the X-axis direction (more specifically, the positive end of the end in the Z-axis direction) abuts against a portion corresponding to the second upper side surface 1221 of the bent plate portion of the lid body 136 on the negative side in the X-axis direction.

[0082] The material of the container 120 (container body 135 and lid 136) configured as above is not limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

[0083] Although not shown here, the lid 136 has a liquid injection portion. This liquid injection portion is a portion for injecting the electrolyte into the storage space S of the container 120 when manufacturing the energy storage element 10.

[0084] Each of the pair of electrode terminals 140 (positive electrode terminal 140A and negative electrode terminal 140B) is a member that is electrically connected to the electrode body 110 via the current collector 170. The electrode terminals 140 are metal members that conduct electricity stored in the electrode body 110 to the external space of the energy storage element 10 and introduce electricity into the internal space (accommodation space S) of the energy storage element 10 to store electricity in the electrode body 110. The material of the electrode terminals 140 is not limited, and the electrode terminals 140 (positive electrode terminal 140A and negative electrode terminal 140B) are formed of a conductive member such as aluminum, an aluminum alloy, copper, or a copper alloy, for example. The electrode terminals 140 are connected (joined) to the current collector 170 by crimping, welding, or the like, and are attached to the lid body 136.

[0085] Specifically, each electrode terminal 140 has a terminal body 141 disposed outside the container 120, and a shaft 145 protruding from the terminal body 141 and extending to the inside of the container 120 (inside the storage space S). The electrode terminals 140 of this embodiment are disposed in the cutouts 131 and 132 of the container 120, respectively.

[0086] When the notched portions 131, 132 of the container 120 are viewed from the Y-axis direction, the first upper surface 1212 and the first upper side surface 1211, and the second upper surface 1222 and the second upper side surface 1221 are L-shaped. The terminal main body 141 has a first terminal piece 142 extending along the first upper surface 1212 (or the second upper surface 1222) and a second terminal piece 143 extending from the first terminal piece 142 and along the first upper side surface 1211 (or the second upper side surface 1221). The first terminal piece 142 and the second terminal piece 143 are integral. The first terminal piece 142 and the second terminal piece 143 are located within a projection area of ​​the first upper surface 1212 (or the second upper surface 1222) in the Z-axis direction and within a projection area of ​​the first upper side surface 1211 (or the second upper side surface 1221) in the X-axis direction. That is, the first terminal piece 142 and the second terminal piece 143 are located within the cutout regions R1, R2 of the container 120. Note that the cutout regions R1, R2 in this embodiment are rectangular parallelepiped regions surrounded by the first upper surface 1212 (or the second upper surface 1222), the first upper side surface 1211 (or the second upper side surface 1221), and the two-dot chain line L1 in FIGS.

[0087] The first terminal piece 142 is a plate-like portion extending along the first upper surface 1212 (or the second upper surface 1222) within a projection area of ​​the first upper surface 1212 (or the second upper surface 1222) in the Z-axis direction, and is rectangular when viewed in the Z-axis direction. That is, the first terminal piece 142 is a rectangular plate-like portion extending along the XY plane. This first terminal piece 142 has a first welding surface 142WS extending along the XY plane at its end on the positive side in the Z-axis direction. Furthermore, the dimension of the first terminal piece 142 in the X-axis direction is smaller than the dimension of the first upper surface 1212 (or the second upper surface 1222) in the X-axis direction, and the dimension of the first terminal piece 142 in the Y-axis direction is smaller than the dimension of the first upper surface 1212 (or the second upper surface 1222) in the Y-axis direction.

[0088] The second terminal piece 143 is a plate-like portion extending along the first upper side surface 1211 (or the second upper side surface 1221) within a projection area of ​​the first upper side surface 1211 (or the second upper side surface 1221) in the X-axis direction, and is rectangular when viewed in the X-axis direction. That is, the second terminal piece 143 is a rectangular plate-like portion extending along the YZ plane. The second terminal piece 143 has a second welding surface 143WS extending along the YZ plane at its end on the outer side in the X-axis direction (the side away from the first upper side surface 1211 or the second upper side surface 1221). The dimension of the second terminal piece 143 in the Z-axis direction is smaller than the dimension of the first upper side surface 1211 (or the second upper side surface 1221) in the Z-axis direction, and the dimension of the second terminal piece 143 in the Y-axis direction is smaller than the dimension of the first upper side surface 1211 (or the second upper side surface 1221) in the Y-axis direction. In this embodiment, the dimension of the second terminal piece 143 in the Y-axis direction is the same as the dimension of the first terminal piece 142 in the Y-axis direction.

[0089] The shaft 145 extends into the container 120 through a through-hole 1212a (or 1222a) that penetrates in the Z-axis direction at a position corresponding to the first upper surface 1212 (or the second upper surface 1222) of the lid 136. The shaft 145 is connected (joined) to the current collector 170 by passing through the external gasket 150, the lid 136, the internal gasket 160, and the current collector 170 in that order and then being crimped.

[0090] Each of the pair of external gaskets 150 is disposed between the container 120 and the electrode terminal 140 (more specifically, the terminal main body 141) to provide insulation between the container 120 and the electrode terminal 140. Each of the pair of external gaskets 150 also provides a seal between the peripheral edge of the through-hole 1212a (or 1222a) of the container 120 and the shaft 145 of the electrode terminal 140. The external gasket 150 of this embodiment is located between the container 120 and the electrode terminal 140 (more specifically, the terminal main body 141) and is L-shaped when viewed from the Y-axis direction.

[0091] This external gasket 150 is formed from an electrically insulating resin such as 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 made by adding a filler to any of these.

[0092] Specifically, each external gasket 150 has a first insulating portion 151 disposed between the first upper surface 1212 (or the second upper surface 1222) and the first terminal piece 142, and a second insulating portion 152 disposed between the first upper side surface 1211 (or the second upper side surface 1221) and the second terminal piece 143. The first insulating portion 151 and the second insulating portion 152 are integral with each other.

[0093] The first insulating portion 151 is a plate-like portion extending along the first upper surface 1212 (or the second upper surface 1222) within a projection area of ​​the first upper surface 1212 (or the second upper surface 1222) in the Z-axis direction. Its rectangular shape corresponds to the first terminal piece 142 when viewed in the Z-axis direction. The first insulating portion 151 has a recess 151a into which the first terminal piece 142 fits. The recess 151a is recessed toward the negative side of the Z-axis direction, and the depth (dimension in the Z-axis direction) of the recess 151a is smaller than the thickness (dimension in the Z-axis direction) of the first terminal piece 142. As a result, when viewed in the Y-axis direction, the end of the first terminal piece 142 on the positive side in the Z-axis direction protrudes beyond the first insulating portion 151 (more specifically, the periphery of the recess 151a) toward the positive side in the Z-axis direction (see FIG. 6 ). The first insulating portion 151 also has a through-hole 151b penetrating in the Z-axis direction at a position corresponding to the shaft portion 145 of the electrode terminal 140.

[0094] The second insulating portion 152 is a plate-like portion extending along the first upper side surface 1211 (or the second upper side surface 1221) within a projection area of ​​the first upper side surface 1211 (or the second upper side surface 1221) in the X-axis direction, and has a rectangular shape corresponding to the second terminal piece 143 when viewed in the X-axis direction. The second insulating portion 152 has a recess 152a into which the second terminal piece 143 fits. The recess 152a is recessed inward in the X-axis direction (the side closer to the first upper side surface 1211 or the second upper side surface 1221), and the depth of the recess 152a (the dimension in the X-axis direction) is smaller than the thickness of the second terminal piece 143 (the dimension in the X-axis direction). As a result, when viewed in the Y-axis direction, the outer end of the second terminal piece 143 in the X-axis direction protrudes outward in the X-axis direction beyond the second insulating portion 152 (more specifically, the periphery of the recess 152a) (see FIG. 6 ).

[0095] Each of the pair of internal gaskets 160 is disposed between the container 120 and the current collector 170 to provide insulation between the container 120 and the current collector 170. Each of the pair of internal gaskets 160 also provides a seal between the peripheral edge of the through-hole 1212a (or 1222a) of the container 120 and the shaft portion 145 of the electrode terminal 140.

[0096] Like the external gasket 150, the internal gasket 160 is formed from an electrically insulating resin such as 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 containing any of these with a filler added thereto.

[0097] Each of the pair of collectors 170 is arranged one on each side of the electrode body 110 in the X-axis direction, and is a component that connects (joins) the electrode body 110 and the electrode terminal 140 to establish electrical conductivity between the electrode body 110 and the electrode terminal 140.

[0098] Specifically, the current collector 170 has a first joint portion 171 that is connected (joined) to the tab portion 112 of the electrode body 110 by welding, crimping, etc., and a second joint portion 172 that is connected (joined) to the electrode terminal 140 by crimping, welding, etc. The first joint portion 171 and the second joint portion 172 are each a flat plate-like portion, and are formed by bending a single piece of sheet metal.

[0099] The material of the current collector 170 is not limited, but for example, the positive current collector 170A is formed from a conductive material such as aluminum or an aluminum alloy, similar to the positive current collector foil 1131 of the electrode body 110, and the negative current collector 170B is formed from a conductive material such as copper or a copper alloy, similar to the negative current collector foil 1141 of the electrode body 110.

[0100] The energy storage elements 10 configured as described above are arranged in the energy storage element group 3 in the Y-axis direction such that the corresponding electrode terminals 140 of adjacent energy storage elements 10 (i.e., adjacent electrode terminals 140) have different polarities. That is, the multiple energy storage elements 10 are arranged in the Y-axis direction with both ends in the X-axis direction alternately inverted. At this time, the long side surfaces 123 of adjacent energy storage elements 10 face each other. Furthermore, at both ends in the X-axis direction of the energy storage element group 3, the notched portions 131, 132 of each energy storage element 10 are arranged alternately in the Y-axis direction.

[0101] The energy storage element group 3 is accommodated in the accommodation space S of the case 20 with the first side surface 1213, the second side surface 1223, the top surface 124, and the bottom surface 125 of each energy storage element 10 included in the energy storage element group 3 in contact with the corresponding cooling surfaces 20CS of the case 20 (in the example of this embodiment, the second side wall 232, the fourth side wall 234, the bottom wall 22, and the inner surfaces 20S of the case lid 25 of the case 20) (see FIG. 7 ). Furthermore, the energy storage element group 3 is accommodated in the accommodation space S of the case 20 with the outer long side surfaces 123 of each energy storage element 10 arranged at both ends in the Y-axis direction in contact with the corresponding inner surfaces 20S of the case 20 (in the example of this embodiment, the inner surfaces 20S of the first side wall 231 and the third side wall 233).

[0102] In this way, the storage element group 3 is accommodated in the case 20 so that each surface (first side surface 1213, second side surface 1223, top surface 124, bottom surface 125) of each storage element 10 constituting the storage element group 3 contacts the corresponding inner surface 20S of the case 20, thereby forming a first space S1 at the corner on the positive side of the X-axis direction and the positive side of the Z-axis direction within the case 20, and a second space S2 at the corner on the negative side of the X-axis direction and the positive side of the Z-axis direction within the case 20 (see Figure 7).

[0103] Each of the first space S1 and the second space S2 extends in the Y-axis direction from the inner surface 20S of the first side wall 231 to the inner surface 20S of the third side wall 233 inside the case 20. The bus bars 30 are arranged in the first space S1 and the second space S2.

[0104] Each of the plurality of bus bars 30 electrically connects the corresponding electrode terminals 140 of adjacent energy storage elements 10 (more specifically, the positive electrode terminals 140A and the negative electrode terminals 140B of adjacent energy storage elements 10), thereby connecting the plurality of energy storage elements 10 in series in the energy storage element group 3. The bus bars 30 are formed from a conductive metal member such as aluminum, an aluminum alloy, copper, a copper alloy, or nickel, or a combination thereof, or a conductive member other than a metal.

[0105] The busbars 30 of this embodiment extend in the Y-axis direction to be able to connect corresponding electrode terminals 140 of at least adjacent energy storage elements 10, and are L-shaped along the electrode terminals 140 when viewed from the Y-axis direction. Specifically, each busbar 30 has a first connection portion 31 that connects corresponding first terminal pieces 142 of energy storage elements 10 that are adjacent in the Y-axis direction in the energy storage element group 3, and a second connection portion 32 that connects corresponding second terminal pieces 143 of the adjacent energy storage elements 10 (see FIG. 2 ).

[0106] The first connection portion 31 is a plate-like portion that extends along the XY plane and is elongated in the Y-axis direction, and in this embodiment, the first connection portion 31 has a rectangular shape that is elongated in the Y-axis direction when viewed from the Z-axis direction. The dimension of this first connection portion 31 in the X-axis direction corresponds to the dimension of the first terminal piece 142 of the electrode terminal 140 in the X-axis direction, and the dimension in the Y-axis direction is a dimension that overlaps with both of the two first terminal pieces 142 that are adjacent in the Y-axis direction in the energy storage element group 3.

[0107] The second connecting portion 32 is a plate-like portion that extends along the YZ plane and is elongated in the Y-axis direction, and in this embodiment, the second connecting portion 32 has a rectangular shape that is elongated in the Y-axis direction when viewed from the X-axis direction. The dimension of this second connecting portion 32 in the Z-axis direction corresponds to the dimension of the second terminal piece 143 of the electrode terminal 140 in the Z-axis direction, and the dimension of the second connecting portion 32 in the Y-axis direction is the same as the dimension of the first connecting portion 31 in the Y-axis direction.

[0108] The first connection portion 31 and the second connection portion 32 are integral with each other. Each bus bar 30 is connected (conductively connected) to two corresponding electrode terminals 140 (i.e., a positive terminal 140A and a negative terminal 140B adjacent in the Y-axis direction) of adjacent energy storage elements 10 in the energy storage element group 3 by welding the first connection portion 31 to the first welding surfaces 142WS of the first terminal pieces 142 of both electrode terminals 140A, 140B and welding the second connection portion 32 to the second welding surfaces 143WS of the second terminal pieces 143 of both electrode terminals 140A, 140B. When the energy storage element group 3 is viewed from the Y-axis direction, each bus bar 30 is located within the first space S1 or the second space S2 (i.e., the notched regions R1, R2 extending in the Y-axis direction) (see FIG. 7 ).

[0109] In addition, in the energy storage device 1 of this embodiment, the positive terminal 140A of the energy storage element 10 at the positive end in the Y-axis direction in the energy storage element group 3 is connected to the first general terminal 235 via a general terminal wire, and the negative terminal 140B of the energy storage element 10 at the negative end in the Y-axis direction in the energy storage element group 3 is connected to the second general terminal 236 via a general terminal wire.

[0110] The energy storage element 10 provided in the energy storage device 1 described above includes an electrode body 110 formed by stacking a plurality of electrode plates 113, 114, a container 120 for accommodating the electrode body 110, and a pair of electrode terminals 140 that are electrically connected to the electrode body 110. When viewed from the Y-axis direction (first direction), which is a predetermined horizontal direction, the container 120 has a rectangular shape that is elongated in the X-axis direction (second direction), which is perpendicular to the Y-axis direction and is horizontal, and has notches at least in two of the four corners of the rectangle on the positive side (one side) in the Z-axis direction (up-down direction).When viewed from the Y-axis direction, each notch shape is composed of a first top surface (first face) 1212 or a second top surface (first face) 1222 that extends from the short side of the rectangle toward the center of the rectangle in the X-axis direction, and a first upper side surface (second face) 1211 or a second upper side surface (second face) 1221 that extends from the tip of the first top surface 1212 or the second top surface 1222 toward one long side of the rectangle in the Z-axis direction.Each electrode terminal 140 is L-shaped along the first top surface 1212, the first upper side surface 1211, the second top surface 1222, and the second upper side surface 1221.

[0111] The energy storage device 1 of this embodiment comprises a plurality of energy storage elements 10 arranged in the Y-axis direction (first direction) and at least one conductive bus bar 30, which extends in the Y-axis direction (first direction) so as to be able to connect corresponding electrode terminals 140 of at least adjacent energy storage elements 10, and is L-shaped along the electrode terminals 140 when viewed from the Y-axis direction.

[0112] In this energy storage device 1, the L-shaped electrode terminal 140 of each energy storage element 10 has two portions (a first terminal piece 142 and a second terminal piece 143) sandwiched between a bent portion, so that when the bus bar 30 connects corresponding electrode terminals 140 of at least adjacent energy storage elements 10, the bus bar 30 is connected to the two portions (the first terminal piece 142 and the second terminal piece 143) of each electrode terminal 140, respectively, thereby ensuring a sufficient area for the connection portion between the electrode terminal 140 and the bus bar 30.

[0113] In addition, the storage element 10 of this embodiment is provided with a pair of external gaskets (insulating parts) 150 that electrically insulate the container 120 and the electrode terminal 140, and each external gasket 150 is located between the container 120 and the electrode terminal 140 and is L-shaped when viewed from the Y-axis direction (first direction).

[0114] According to this configuration, the external gasket 150 (first insulating portion 151 or second insulating portion 152) is located between the first upper surface 1212 or the second upper surface 1222 of the container 120 and the first terminal piece 142 along the first upper surface 1212 or the second upper surface 1222 of the electrode terminal 140, and between the first upper side surface 1211 or the second upper side surface 1221 of the container 120 and the second terminal piece 143 along the first upper side surface 1211 or the second upper side surface 1221 of the electrode terminal 140, respectively, so that the container 120 and the electrode terminal 140 are sufficiently insulated from each other.

[0115] Furthermore, in the energy storage element of this embodiment, the first terminal piece (first portion) 142 along the first upper surface (first surface) 1212 or the second upper surface (first surface) 1222 of the electrode terminal 140 is located within a projection area of ​​the first upper surface or the second upper surface in the Z-axis direction (vertical direction), and the second terminal piece (second portion) 143 along the first upper side surface (second surface) 1211 or the second upper side surface (second surface) 1221 of the electrode terminal 140 is located within a projection area of ​​the first upper side surface (second surface) 1211 or the second upper side surface (second surface) 1221 in the X-axis direction. This prevents contact between the electrode terminals 140 of adjacent energy storage elements 10 (more specifically, contact between the first terminal pieces 142 and contact between the second terminal pieces 143) when multiple energy storage elements 10 are arranged in the Y-axis direction. Furthermore, with this configuration, when the storage element group 3 is viewed from the Y-axis direction, the electrode terminals 140 are prevented from protruding from the top surface 124 of each storage element 10 in the Z-axis direction toward the positive side in the Z-axis direction, and the electrode terminals 140 are prevented from protruding outward in the X-axis direction from the first side surface 1213 and second side surface 1223 of each storage element 10 in the X-axis direction.

[0116] In the energy storage device 1 of this embodiment, the first connection portion 31 and the second connection portion 32 of the bus bar 30 are integral with each other. Since the first connection portion 31 and the second connection portion 32 are integral with each other in this manner, the electrical resistance of the bus bar 30 is reduced.

[0117] The energy storage device 1 of this embodiment also includes a case portion (element container) 2 in which at least one of a plurality of inner surfaces 20S that define the internal storage space S is a cooling surface 20CS, and the case portion 2 accommodates an energy storage element group 3 including a plurality of energy storage elements 10 and at least one bus bar 30 such that the energy storage element group 3 is in contact with the cooling surface 20CS. In this way, the energy storage element group 3 accommodated in the case portion 2 is cooled by being in contact with the cooling surface 20CS, and therefore, a temperature rise in the energy storage element group 3 (each energy storage element 10) during charging and discharging is suppressed.

[0118] Furthermore, in the energy storage device 1 of this embodiment, the busbar 30 is located within a projection area in the Z-axis direction (vertical direction) of the first upper surface (first surface) 1212 or the second upper surface (first surface) 1222, and within a projection area in the X-axis direction (second direction) of the first upper side surface (second surface) 1211 or the second upper side surface (second surface) 1221 (within the cutout areas R1, R2 as viewed from the Y-axis direction).

[0119] With this configuration, the busbar 30 does not protrude outward in the X-axis direction or to the positive side in the Z-axis direction when viewed from the Y-axis direction in the storage element group 3, thereby preventing the occurrence of dead space within the storage space S due to the protrusion of the busbar 30.

[0120] The energy storage element and energy storage device of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, or part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment can be deleted.

[0121] In the energy storage device 1 of the above embodiment, the energy storage elements 10 constituting the energy storage element group 3 are connected in series by the bus bars 30, but this configuration is not limiting. The energy storage elements 10 constituting the energy storage element group 3 may also be connected in parallel by the bus bars 30.

[0122] In the energy storage element 10 of the above embodiment, the notches 131, 132 in which the electrode terminals 140 are arranged are provided in the upper two of the four corners when the container 120 is viewed from the Y-axis direction, but this configuration is not limiting. The notches 131, 132 in which the electrode terminals 140 are arranged may also be provided in the lower two of the four corners when the container 120 is viewed from the Y-axis direction.

[0123] In addition, in the energy storage element 10 of the above embodiment, the notch portion 131 on the positive side in the X-axis direction and the notch portion 132 on the negative side have the same shape and size, but they may be different. That is, the first upper side surface 1211 and the second upper side surface 1221 may have different shapes and sizes, and the first upper surface 1212 and the second upper surface 1222 may have different shapes and sizes.

[0124] Furthermore, in the energy storage element 10 of the above embodiment, the first top surface 1212 and the first upper side surface 1211 of the cutout portion 131 of the container 120 are L-shaped along the X-axis direction and the Z-axis direction, but the first top surface 1212 may be slightly inclined with respect to the X-axis direction, and the first upper side surface 1211 may be slightly inclined with respect to the Z-axis direction. Similarly, the external gasket 150, the terminal main body 141, and even the bus bar 30 are L-shaped along the X-axis direction and the Z-axis direction when viewed from the Y-axis direction, but they may be configured to have a shape that follows the first top surface 1212 and the first upper side surface 1211. The same applies to the cutout portion 132.

[0125] Furthermore, in the energy storage device 10 of the above embodiment, the shape of the container 120 as viewed in the X-axis direction is rectangular, but is not limited to this configuration. For example, the container 120A may be oval as viewed in the X-axis direction, as shown in FIG. 8 . Specifically, the top surface 124A of the container 120A may be arc-shaped and convex upward as viewed in the X-axis direction, and the bottom surface 125A may be arc-shaped and convex downward as viewed in the X-axis direction. Furthermore, the container 120 may be circular, polygonal, or the like as viewed in the X-axis direction. That is, the container 120 may be rectangular as viewed in the Y-axis direction and have notches at two of its four corners on one side in the Z-axis direction.

[0126] Furthermore, in the energy storage element 10 of the above embodiment, the terminal body 141 of the electrode terminal 140 has two terminal pieces (first terminal piece 142 and second terminal piece 143) arranged in an L-shape when viewed from the Y-axis direction, but this configuration is not limited to this. For example, in addition to the first terminal piece 142 and the second terminal piece 143, the terminal body 141 may have a plate-shaped third terminal piece that extends from the outer end of the first terminal piece 142 in the X-axis direction to the positive side in the Z-axis direction and extends along the YZ plane. In other words, the terminal body 141 may be U-shaped when viewed from the Y-axis direction. In this case, the surface of the third terminal piece facing the second terminal piece 143 is the welding surface.

[0127] Furthermore, there are no limitations on the specific shape of each terminal piece (first terminal piece 142, second terminal piece 143). Although each terminal piece 142, 143 in the above embodiment has a rectangular shape when viewed from the normal direction of the welding surfaces 142W, 143W, the end of the terminal piece 143 may have an arc shape (see FIG. 8 ), for example.

[0128] In addition, in the storage element group 3 of the above embodiment, multiple storage elements 10 are arranged so that adjacent storage elements 10 are in contact with each other, but spacers, insulating members, etc. may also be arranged between adjacent storage elements 10 in the Y-axis direction.

[0129] In addition, in the bus bar 30 of the above embodiment, the first connection portion 31 and the second connection portion 32 are integral with each other, but this configuration is not limiting. The first connection portion 31 and the second connection portion 32 may be separate bodies.

[0130] 1...electricity storage device, 2...case portion, 20...case, 20CS...cooling surface, 20S...inner surface, 21...case body, 210...peripheral wall, 21A...opening, 22...bottom wall, 23...peripheral wall, 231...first side wall, 232...second side wall, 233...third side wall, 234...fourth side wall, 235...first main terminal, 236...second main terminal, 25...case lid body, 26...refrigerant pipe, 3...electricity storage element group, 30...bus bar, 31...first connecting portion, 32...second connecting portion, 10, 10A...electricity storage element, 110...electrode body, 111...main body portion, 1111 ...curved portion, 1112...flat portion, 112...tab portion, 112a...positive electrode tab portion, 112b...negative electrode tab portion, 113...positive electrode plate (electrode plate), 1131...positive electrode current collector foil, 1132...positive electrode active material layer, 1133...projecting piece, 114...negative electrode plate (electrode plate), 1141...negative electrode current collector foil, 1142...negative electrode active material layer, 1143...projecting piece, 115, 116...separator, 120, 120A...container, 121...first side end surface portion, 1211...first upper side surface, 1212...first upper surface, 1212a...through hole, 1213...first side surface , 122...second side end surface portion, 1221...second upper side surface, 1222...second upper surface, 1222a...through hole, 1223...second side surface, 123...long side surface, 124, 124A...top surface, 125, 125A...bottom surface, 131, 132...notch portion, 135...container body, 136...lid body, 140...electrode terminal, 140A...positive electrode terminal, 140B...negative electrode terminal, 141...terminal body portion, 142...first terminal piece (first portion), 142WS...first welding surface, 143...second terminal piece (second portion), 143WS...second welding surface, 145...shaft portion, 150...external gasket, 151...first insulating portion, 151a...recess, 151b...through hole, 152...second insulating portion, 152a...recess, 160...internal gasket, 170...current collector, 170A...positive electrode current collector, 170B...negative electrode current collector, 171...first bonding portion, 172...second bonding portion, 500...non-aqueous electrolyte secondary battery, 501...external can, 502...positive electrode terminal, 503...main body portion, 504...surface, L...winding axis, R1, R2...notched region, S...accommodation space, S1...first space, S2...second space

Claims

1. An energy storage element comprising: an electrode assembly formed by stacking a plurality of electrode plates; a container that houses the electrode assembly; and a pair of electrode terminals that are electrically connected to the electrode assembly, wherein the container has a rectangular shape that, when viewed from a first direction that is a predetermined horizontal direction, is elongated in a second horizontal direction that is perpendicular to the first direction, and at least two of the four corners of the rectangle have cutout shapes at one of the corners in the vertical direction, each cutout shape being constituted by a first surface that extends from a short side of the rectangle toward the center of the rectangle in the second direction, when viewed from the first direction, and a second surface that extends from a tip of the first surface toward one of the long sides of the rectangle in the vertical direction, and each electrode terminal is L-shaped along the first surface and the second surface when viewed from the first direction.

2. The energy storage element according to claim 1, further comprising a pair of insulating parts that electrically insulate the container from the electrode terminal, each insulating part being positioned between the container and the electrode terminal and being L-shaped when viewed from the first direction.

3. A storage element as described in claim 1, wherein a first portion of the electrode terminal along the first surface is located within a projection area of ​​the first surface in the up-down direction, and a second portion of the electrode terminal along the second surface is located within a projection area of ​​the second surface in the second direction.

4. An energy storage device comprising: a plurality of energy storage elements according to any one of claims 1 to 3 arranged in the first direction; and at least one electrically conductive bus bar, wherein the bus bar extends in the first direction so as to be able to connect corresponding electrode terminals of at least adjacent energy storage elements to each other, and is L-shaped along the electrode terminals when viewed from the first direction.

5. The energy storage device according to claim 4, comprising an element container in which at least one of a plurality of inner surfaces defining an internal storage space is a cooling surface, the element container housing a group of energy storage elements including the plurality of energy storage elements and the at least one bus bar so that the group of energy storage elements is in contact with the cooling surface.

6. The energy storage device according to claim 5, wherein the bus bar is located within a projection area of ​​the first surface in the vertical direction and within a projection area of ​​the second surface in the second direction when viewed from the first direction.

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