Power storage element and power storage device

Abstract

The power storage element of the present embodiment includes: an electrode body that stacks a plurality of electrode plates; a container that houses the electrode body; and a pair of electrode terminals that are in conduction with the electrode body. When viewed from a first direction that is a prescribed horizontal direction, the container is a long rectangle that has a long dimension in a second direction that is orthogonal to the first direction and horizontal, and is a long rectangle that has a notch shape at two corners of the long rectangle on one side in an up-down direction, the notch shape being formed by a terminal arrangement surface that extends in an oblique direction that intersects with a long side of the one side in the up-down direction, a short side of the second direction of the long rectangle, or a short side of the other side of the second direction in the long rectangle when viewed from the first direction, and the electrode terminals are arranged at the terminal arrangement surfaces, respectively.

Description

Technical Field

[0001] This invention relates to energy storage elements and energy storage devices having multiple energy storage elements. Background Technology

[0002] Previously, rectangular parallelepiped-shaped secondary batteries (energy storage elements) were known (see Patent Document 1). For example... Figure 9 As shown, the secondary battery 500 includes a battery housing (container) 501 for housing flat wound electrodes, and a positive terminal 504 and a negative terminal 505 disposed in the battery housing 501.

[0003] Specifically, the battery casing 501 comprises a flat, box-shaped (cubic-pole) casing body 502 with an open top and a bottom, and a cover 503 that blocks the opening of the casing body 502. A positive terminal 504, electrically connected to the positive electrode plate of the flat wound electrode body, and a negative terminal 505, electrically connected to the negative electrode plate of the flat wound electrode body, are provided on the upper surface of the battery casing 501 (i.e., the cover 503). These positive and negative terminals 504 and 505 are arranged to protrude upwards from the cover 503.

[0004] In the case where multiple adjacent secondary batteries 500 are arranged and their corresponding terminals (positive terminal 504 and negative terminal 505) are connected by a busbar B and housed in a component container 506 to form an energy storage device 507, since the positive terminal 504 and negative terminal 505 protrude upwards from the battery casing 501, therefore... Figure 10 As shown, a useless space is created between the upper surface of the battery housing 501 and the upper inner wall of the component container 506. Figure 10 (The range shown by the midpoint) DS, the energy density inside the component container 506 decreases, and therefore, the energy density of the energy storage device 507 itself also decreases.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-129474 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] Therefore, the purpose of this embodiment is to provide an energy storage element that can improve the energy density of the energy storage device when the energy storage element is housed in the energy storage device, and an energy storage device having the energy storage element.

[0010] Technical solutions for solving technical problems

[0011] The energy storage element in this embodiment includes: An electrode body, which consists of multiple stacked electrode plates; A container that houses the electrode body; and A pair of electrode terminals, which are in communication with the electrode body. Viewed from a first direction, which is defined as a horizontal direction, the container is a rectangle with a longer dimension in a second direction orthogonal to the first direction and horizontal, and is a rectangle with cutouts at least on two corners on one side in the vertical direction. The cutout shapes are each formed by terminal mounting surfaces, which are arranged in an inclined direction in the rectangle as viewed from the first direction, intersecting the long side of one side of the vertical direction and the short side of one side of the rectangle in the second direction or the short side of the rectangle in the other side of the second direction. The electrode terminals are respectively disposed on the terminal configuration surface.

[0012] In addition, the energy storage device of this embodiment includes: Multiple energy storage elements of this embodiment are arranged in the first direction; and At least one busbar that connects the corresponding electrode terminals of adjacent energy storage elements to each other. The corresponding terminal configuration surfaces of the adjacent energy storage elements are arranged in the first direction along a common imaginary surface that extends in both the inclined direction and the first direction.

[0013] Invention Effects

[0014] As described above, according to the present invention, when this energy storage element is housed in an energy storage device, the useless space between the upper surface of the battery casing and the upper inner wall of the element container can be reduced, and this space can be effectively utilized to make the energy storage element larger. As a result, the effective active material mass of the electrode body in the energy storage device increases, thereby improving the energy density of the energy storage device. Therefore, according to the present invention, an energy storage element capable of improving the energy density of an energy storage device and an energy storage device having the energy storage element can be provided. Attached Figure Description

[0015] Figure 1 This is a perspective view of the energy storage device according to this embodiment.

[0016] Figure 2 This is an exploded perspective view of the energy storage device.

[0017] Figure 3 This is a three-dimensional view of the energy storage elements of the energy storage device.

[0018] Figure 4 This is an exploded perspective view of the energy storage element.

[0019] Figure 5 This is a diagram illustrating the structure of the electrode body of the energy storage element.

[0020] Figure 6 This is an abbreviated diagram of the energy storage element.

[0021] Figure 7 This is a longitudinal cross-sectional view of the energy storage device, with the middle section omitted.

[0022] Figure 8 This is a perspective view of an energy storage element in other embodiments.

[0023] Figure 9 It is a 3D diagram of a traditional secondary battery.

[0024] Figure 10 This is a longitudinal cross-sectional view of an energy storage device equipped with the aforementioned secondary battery. Detailed Implementation

[0025] (1) An energy storage element according to one embodiment of the present invention comprises: An electrode body, which consists of multiple stacked electrode plates; A container that houses the electrode body; and A pair of electrode terminals, which are in communication with the electrode body. Viewed from a first direction, which is defined as a horizontal direction, the container is a rectangle with a longer dimension in a second direction orthogonal to the first direction and horizontal, and is a rectangle with cutouts at least on two corners on one side in the vertical direction. The cutout shapes are each formed by terminal mounting surfaces, which are arranged in an inclined direction in the rectangle as viewed from the first direction, intersecting the long side of one side of the vertical direction and the short side of one side of the rectangle in the second direction or the short side of the rectangle in the other side of the second direction. The electrode terminals are respectively disposed on the terminal configuration surface.

[0026] According to an embodiment of the present invention, an energy storage element has electrode terminals arranged along the terminal arrangement surfaces provided at the two corners of a rectangle when viewed from a first direction. Therefore, it is possible to suppress the useless space (remaining space) caused by the protrusion of the electrode terminals when the energy storage element is housed in the element container, as well as the useless space caused by the busbar connection between the electrode terminals. As a result, the energy density of the energy storage device when the energy storage element is housed in the energy storage device can be improved.

[0027] (2) Among the energy storage elements described in (1) above, it is also possible to have: The electrode terminal is located within the projection area of ​​the terminal configuration surface in the vertical direction and within the projection area of ​​the terminal configuration surface in the second direction.

[0028] According to the energy storage element described in (2) above, when multiple energy storage elements are arranged along the first direction, accidental contact between the electrode terminals of adjacent energy storage elements can be suppressed. In addition, when multiple energy storage elements are arranged along the first direction, it is also possible to suppress the protrusion of the electrode terminals from one end edge position of each energy storage element in the vertical direction when viewed from the first direction, and the protrusion of the electrode terminals from both end edges positions of each energy storage element in the second direction.

[0029] (3) Among the energy storage elements described in (1) above, it is also possible to be, The electrode body is constructed by winding the electrode plates in an oblong shape when viewed from the second direction. When viewed from the second direction, the container appears as an elongated oval shape corresponding to the electrode body.

[0030] According to the energy storage element described in (3) above, when the wound electrode body is placed in the container, the gap between the outer periphery of the electrode body and the inner surface of the container becomes smaller. This increases the energy density of the energy storage element, and the electrode body can be uniformly pressurized within the container, preventing deformation of the electrode body during charging and discharging. (For example, see reference...) Figure 8 。 ).

[0031] (4) The energy storage device according to one embodiment of the present invention comprises: A plurality of energy storage elements as described in any one of (1) to (3) above, arranged in the first direction; and At least one busbar that connects the corresponding electrode terminals of adjacent energy storage elements to each other. The corresponding terminal configuration surfaces of the adjacent energy storage elements are arranged in the first direction along a common imaginary surface that extends in both the inclined direction and the first direction.

[0032] According to an embodiment of the present invention, an energy storage device has electrode terminals arranged along the terminal arrangement surfaces provided at the two corners of a rectangle when viewed from a first direction. Therefore, it is possible to suppress the useless space caused by the protrusion of the electrode terminals when multiple energy storage elements are housed in the energy storage device, thereby improving the energy density of the energy storage device.

[0033] (5) The energy storage device described in (4) above may also be, The component container has at least one of its multiple inner surfaces that define an internal storage space as a cooling surface. The component container houses the energy storage element group in such a manner that the energy storage element group, which includes the plurality of energy storage elements and the at least one busbar, is in contact with the cooling surface.

[0034] According to the energy storage device described in (5) above, the energy storage element group housed in the element container is cooled by contact with the cooling surface, thus suppressing the temperature rise of the energy storage element group during charging and discharging.

[0035] (6) In the energy storage device described in (5) above, it may also be that... Viewed from the first direction, the busbar is located within the projection area of ​​the terminal configuration surface in the vertical direction and within the projection area of ​​the terminal configuration surface in the second direction.

[0036] According to the energy storage device described in (6) above, when viewed from the first direction in the energy storage element group, the busbar does not protrude to the outside of the second direction or to the side of the vertical direction. Therefore, it is possible to suppress the generation of useless space in the storage space caused by the protrusion of the busbar (for example, see reference). Figure 7 ).

[0037] The following is for reference Figures 1 to 7 An embodiment of the present invention will be described. It should be noted that the names of the constituent components (elements) in this embodiment are specific to this embodiment and may sometimes differ from the names of the constituent components (elements) in the background art.

[0038] Furthermore, in the following description and accompanying drawings, the direction of the long side of the energy storage element and the direction along the winding axis of the electrode body of 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 energy storage element container are defined as the Y-axis direction (first direction). The arrangement direction of the housing cover and housing body of the energy storage device, and the arrangement direction or vertical direction of the bottom surface of the container body and the top surface of the cover are defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions are intersecting (or orthogonal in this embodiment). Additionally, in the following description, when "insulated," it means "electrically insulating." It should be noted that, in this embodiment, for example, the positive X-axis direction represents the direction of the arrow on the X-axis, and the negative X-axis direction represents the direction opposite to the positive X-axis direction. This also applies to the Y-axis and Z-axis directions.

[0039] An energy storage device is a device that can be charged with electricity from an external source and discharged to an external source, such as... Figure 1As shown, the energy storage device 1 of this embodiment has a generally rectangular parallelepiped shape. This energy storage device 1 is a battery module (battery pack) used for purposes such as electricity storage or power supply, for example, as a battery for driving or starting the engine of a moving vehicle such as a car, motorized two-wheeler, boat, ship, snowmobile, agricultural machinery, construction machinery, or railway vehicle for electric railways. Examples of such cars include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, light oil, liquefied natural gas, etc.) vehicles. Examples of such railway vehicles for electric railways include trams, monorail trains, maglev trains, automated guided vehicles (AGVs), and hybrid trams equipped with both a diesel engine and an electric motor. Furthermore, the energy storage device 1 can also be used as a stationary battery for household or commercial use.

[0040] Specifically, such as Figure 2 and Figure 3 As shown, the energy storage device 1 includes: an energy storage element group 3, which includes a plurality of energy storage elements 10 and at least one (in this embodiment, a plurality of) busbars 30; and a housing (element container) 2, which houses the energy storage element group 3. In addition to the above-described components, the energy storage device 1 may also include constraint members (end plates, side plates, etc.) for constraining the plurality of energy storage elements 10, a busbar support for holding the busbars 30, a busbar cover, a circuit board for monitoring or controlling the charging and discharging states of the energy storage elements 10, and electrical components such as relays, fuses, shunt resistors, and connectors.

[0041] The housing 2 includes: a housing 20 having an internal storage space S; and a refrigerant pipe 26 for cooling the energy storage element assembly 3 via the housing 20.

[0042] The housing 20 is a container (module housing) that is approximately cuboid in shape (box-shaped) and constitutes the outer body (frame, shell) of the energy storage device 1. The storage space S is also cuboid in shape or approximately cuboid in shape. That is, the housing 20 has 6 (more) inner surfaces 20S that define the storage space S, and each inner surface 20S is a rectangular flat surface.

[0043] The housing 20 secures (holds) the energy storage element group 3 in a predetermined position by housing it within the storage space S, thereby protecting each energy storage element 10 contained in the energy storage element group 3 from impacts, vibrations, etc. In the housing 20 of this embodiment, after each energy storage element 10 is compressed and housed within the housing 20, the restoring force of the energy storage element 10 fixes each energy storage element 10 within the housing 20.

[0044] The housing 20 is a metal casing formed from metal components such as aluminum, aluminum alloy, stainless steel, iron, or coated steel sheet. Therefore, the housing 20 can efficiently dissipate heat from each energy storage element 10 to the outside of the housing 20, suppressing or cooling the temperature rise of each energy storage element 10. It should be noted that if the housing 20 is conductive, its inner surface can be covered with an insulating material to ensure insulation from the energy storage element group 3. It should also be noted that the housing 20 is not limited to being made of metal; it can also be made of resin, etc.

[0045] The housing 20 of this embodiment includes: a housing body 21 having an opening 21A and constituting the housing 20; and a housing cover 25 that closes the opening 21A. Furthermore, in the housing 20 of this embodiment, the housing body 21 and the housing cover 25 are formed of the same material, but they may also be formed of different materials.

[0046] The main body 21 of the housing is on the positive side in the Z-axis direction ( Figure 2 The top side of the tube has an opening 21A and a bottomed square tube to house the energy storage component group 3, etc.

[0047] Specifically, the housing body 21 has a plate-shaped bottom wall 22 extending in a plane direction orthogonal to the Z-axis direction and a peripheral wall 23 extending from the periphery of the bottom wall 22 toward the positive side in the Z-axis direction. In this embodiment, the bottom wall 22 is rectangular and the peripheral wall 23 is cylindrical.

[0048] The peripheral wall 23 is constructed by continuously arranging four rectangular plate-shaped side walls (first side wall 231, second side wall 232, third side wall 233, and fourth side wall 234) along the periphery of the bottom wall 22 in the circumferential direction. In the peripheral wall 23 of this embodiment, the first side wall 231 has a first main terminal 235, and the third side wall 233 has a second main terminal 236. It should be noted that the position of the main terminal in the peripheral wall 23 is not limited. That is, the position of the main terminal in the peripheral wall 23 varies depending on the terminal position of the energy storage element 10, the number of energy storage elements 10 arranged in the housing 20 (the number of stacks), the series connection or parallel connection relationship of the energy storage elements 10 and the energy storage element group 3 in the housing 20, etc.

[0049] The first main terminal 235 is a terminal that supplies power from the outside of the housing 20 to the energy storage element group 3 housed inside the housing 20, or supplies power from the energy storage element group 3 to the outside of the housing 20. In this embodiment, the first main terminal 235 is disposed on the negative side of the first sidewall 231 in the X-axis direction. Figure 2 The end of the left side of the middle and the positive side of the Z-axis direction.

[0050] Furthermore, the second main terminal 236 is a terminal for outputting power from the energy storage element group 3 housed within the housing 20 to the outside of the housing 20, or for inputting power from the outside of the housing 20 to the energy storage element group 3. In this embodiment, the second main terminal 236 is disposed on the positive side of the third sidewall 233 in the X-axis direction ( Figure 2 The right end of the middle and the positive end in the Z-axis direction.

[0051] The housing cover 25 is a part or component that blocks the rectangular opening 21A of the housing body 21, and is a rectangular plate-shaped part located in the XY plane.

[0052] In the housing 20 of this embodiment, the housing body 21 and the housing cover 25, which are configured as described above, are joined by welding, fusion, thread fastening, etc., thereby sealing the storage space S.

[0053] The refrigerant pipe 26 cools the energy storage element assembly 3 via the housing 20 by allowing refrigerant, such as gas or fluid, to circulate internally. In this embodiment, the refrigerant pipe 26 is disposed on the outer surface of the housing 20 (in...). Figure 2 (Illustrations omitted). The refrigerant pipe 26 is welded to the housing 20. In this embodiment, the outer surfaces of the two opposing sidewalls (second sidewall 232 and fourth sidewall 234) of the refrigerant pipe 26 in the X-axis direction, the lower surface of the bottom wall 22, and the upper surface of the housing cover 25 are arranged in a corrugated shape. By allowing refrigerant to flow through the refrigerant pipe 26, the housing 20 (the portion where the refrigerant pipe 26 is disposed) is cooled, thereby at least one of the plurality of inner surfaces 20S of the housing 20 constitutes a cooling surface 20CS.

[0054] The cooling surface 20CS is in contact with the energy storage element group 3 (more specifically, each energy storage element 10) housed in the storage space S of the housing 20 (see reference). Figure 7 In this embodiment, the surfaces capable of cooling the energy storage element group 3 (each energy storage element 10) are cooled via refrigerant pipes 26 that allow refrigerant to flow through the refrigerant. The inner surfaces 20S of these walls 232, 234, 22, and 25 respectively constitute cooling surfaces 20CS. That is, the housing 20 of this embodiment has four cooling surfaces 20CS. It should be noted that this embodiment has been described from the perspective of cooling the energy storage elements 10, but it is self-evident that the structure of this embodiment is useful not only from the perspective of cooling but also from the perspective of heating the energy storage elements 10 in extremely low temperature environments.

[0055] The energy storage element group 3 includes: a plurality of energy storage elements 10, each having a pair of electrode terminals 140 (positive terminal 140A and negative terminal 140B) and arranged in the Y-axis direction; and a plurality of busbars 30 connecting (conducting) the corresponding electrode terminals 140 of adjacent energy storage elements 10 to each other. 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 the corresponding electrode terminals of adjacent energy storage elements 10 (specifically, the electrode terminals 140 connected by the busbars 30) have different polarities (i.e., the positive terminal 140A and the negative terminal 140B are adjacent in the Y-axis direction). Thus, the energy storage elements 10 of the energy storage element group 3 are connected in series with each other.

[0056] The energy storage element 10 is charged with electricity from an external source and also discharges to an external source. The energy storage element 10 in this embodiment is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery, but it is not limited to this; it can be a secondary battery other than a non-aqueous electrolyte secondary battery, or it can be a capacitor. Alternatively, the energy storage element 10 may not be a secondary battery, but rather a primary battery that allows the stored electricity to be used even without charging by the user. Furthermore, the energy storage element 10 can be a solid-state lithium battery, such as a solid-state lithium battery, or a polymer lithium battery. Additionally, the energy storage element 10 can be a pouch-type energy storage element. The energy storage element 10 in this embodiment has a generally rectangular shape with a long dimension in the X-axis direction, but the shape of the energy storage element 10 is not limited to a generally rectangular shape; it can also be a polygonal prism, a long cylindrical shape, an elliptical cylindrical shape, or a cylindrical shape, etc.

[0057] 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, it has a cuboid shape (square, rectangular) that is flat in the Y-axis direction and elongated in the X-axis direction. Figures 3-6 As shown, the energy storage element 10 includes: an electrode body 110 having multiple stacked electrode plates 113 and 114; a container 120 for housing the electrode body 110; and a pair of electrode terminals 140 that are in communication with the electrode body 110. Additionally, the energy storage element 10 has a pair of external gaskets (insulating portions) 150 outside the container 120. Furthermore, the energy storage element 10 has a pair of internal gaskets 160 and a pair of current collectors 170 inside the container 120.

[0058] The electrode body 110 is an energy storage element (power generation element) capable of storing electricity, with multiple electrode plates 113 and 114 wound in a stacked state. In this embodiment, the electrode body 110 has an elongated shape in the X-axis direction, and when viewed from the X-axis direction, it has an elongated oval shape (racetrack shape). Furthermore, the dimension of the electrode body 110 in the X-axis direction is larger than its dimension in the Z-axis direction. In this embodiment, the dimension of the electrode body 110 in the X-axis direction is, for example, 300 mm or more, specifically approximately 500 mm to 1500 mm. Additionally, in this embodiment, the dimension of the electrode body 110 in the X-axis direction is, for example, more than three times the dimension in the Z-axis direction. Specifically, the electrode body 110 includes a main body portion 111 and multiple tabs 112 protruding from the main body portion 111.

[0059] Multiple tabs 112 are portions (connecting portions) in the electrode body 110 that connect (join) with the current collector 170. In this embodiment, one tab protrudes from each end of the main body 111 in the X-axis direction. That is, the electrode body 110 has two tabs 112. For example, a positive tab 112a is disposed on the positive side end of the main body 111 in the X-axis direction, and a negative tab 112b is disposed on the negative side end of the main body 111 in the X-axis direction. It should be noted that... Figure 4 and Figure 5 The tab 112 shown is an example of a connection portion that is connected to the current collector 170, but this embodiment is not limited to this structure.

[0060] Specifically, the electrode body 110 has a positive electrode plate 113, a negative electrode plate 114, and diaphragms 115 and 116.

[0061] The positive electrode plate 113 has a positive electrode current collector foil 1131 that is a long strip of metal foil and a positive electrode active material layer 1132 disposed on both sides of the positive electrode current collector foil 1131.

[0062] The positive electrode current collector foil 1131 is made of aluminum or an aluminum alloy. Furthermore, the positive electrode active material constituting the positive electrode active material layer 1132 is a polyanionic compound such as LiMPO4, LiMSiO4, or LiMBO3 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4, or LiMn... 1.5 Ni 0.5 Spinel-type lithium manganese oxides such as O4, and lithium transition metal oxides such as LiMO2 (where M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) with an α-NaFeO2 type crystal structure. It should be noted that, as the positive electrode active material used in the positive electrode active material layer 1132, any known material that can absorb or release charge-transporting ions can be appropriately used.

[0063] Furthermore, on the positive side edge of the positive electrode plate 113 in the X-axis direction, a plurality of protruding pieces 1133 are arranged at intervals, protruding outwards. Each protruding piece 1133 is a portion of the positive electrode current collector foil 1131 exposed where the positive electrode active material layer is not disposed (the non-formed portion of the positive electrode active material layer). Figure 5 The area indicated by the shaded area.

[0064] The negative electrode plate 114 has a negative electrode current collector foil 1141 that is a strip-shaped metal foil and a negative electrode active material layer 1142 disposed on both sides of the negative electrode current collector foil 1141.

[0065] The negative electrode current collector foil 1141 is made of copper or a copper alloy. Furthermore, the negative electrode active material constituting the negative electrode active material layer 1142 is lithium metal, an alloy capable of absorbing or releasing lithium, carbon materials (graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature sintered carbon, amorphous carbon, etc.), silicon oxide, etc. It should be noted that any known material capable of absorbing or releasing charge-transfer ions can be appropriately used as the negative electrode active material used in the negative electrode active material layer 1142.

[0066] Furthermore, multiple protruding tabs 1143 are spaced apart on the negative side edge of the negative electrode plate 114 in the X-axis direction, protruding outwards. Each protruding tab 1143 is a portion of the negative electrode current collector foil 1141 exposed where the negative electrode active material layer is not disposed (the non-formed portion of the negative electrode active material layer). Figure 5 The area indicated by the shaded area.

[0067] The separators 115 and 116 are resin-made microporous sheets. As for the materials of the separators 115 and 116, known materials can be used appropriately as long as they do not impair the performance of the energy storage element 10. For example, the separators 115 and 116 are made of woven fabrics, nonwoven fabrics, or synthetic resin microporous membranes made of polyolefin resins such as polyethylene that are insoluble in organic solvents.

[0068] An electrode body 110 is formed by sequentially stacking and winding the positive electrode plate 113, negative electrode plate 114, and separator 115 and 116 as described above. In the electrode body 110 of this embodiment, the positive electrode plate 113, negative electrode plate 114, separator 115, and 116 are wound in a core-type manner with an elongated oval (racetrack-shaped) cross-section, and wound around a winding axis L extending in the X-axis direction, thereby forming a wound electrode body 110. The winding axis L is an imaginary axis that serves as the central axis when winding the positive electrode plate 113, negative electrode plate 114, and separator 115 and 116. In this embodiment, the winding axis L is a straight line passing through the center of the electrode body 110 and parallel to the X-axis direction (see reference). Figure 5 ).

[0069] Furthermore, by winding the positive electrode plate 113, the negative electrode plate 114, and the separators 115 and 116 in a sequentially stacked state, the plurality of 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 plurality of protruding pieces 1143 of the negative electrode plate 114 overlap at the negative end of the main body 111 in the X-axis direction.

[0070] In the electrode body 110, the overlapping portion of the multiple protruding pieces 1133 of the positive electrode plate 113 is the positive electrode tab 112a. That is, the positive electrode tab 112a is a portion formed by stacking multiple pieces (protruding pieces 1133) of the same polarity of the electrode plate (positive electrode plate 113) among the multiple electrode plates (positive electrode plate 113 and negative electrode plate 114).

[0071] Similarly, in the electrode body 110, the overlapping portion of the multiple protruding pieces 1143 of the negative electrode plate 114 is the negative electrode tab 112b. That is, the negative electrode tab 112b is a portion formed by stacking multiple pieces (protruding pieces 1143) of the same polarity of the electrode plate (negative electrode plate 114) among the multiple electrode plates (positive electrode plate 113 and negative electrode plate 114).

[0072] Thus, the electrode body 110 has a main body portion 111 constituting the main body of the electrode body 110 and electrode tabs 112 (positive electrode tab 112a and negative electrode tab 112b) protruding from each end of the main body portion 111 in the X-axis direction. That is, the electrode body 110 has a pair of electrode tabs 112 composed of the positive electrode tab 112a and the negative electrode tab 112b.

[0073] Furthermore, the main body 111 is a portion of the positive electrode plate 113 in which a positive electrode active material layer 1132 is disposed (formed, coated), a portion of the negative electrode plate 114 in which a negative electrode active material layer 1142 is disposed (formed, coated), and a portion formed by winding the separators 115 and 116 into an elongated cylindrical shape. In this main body 111, the region in which at least one of the positive electrode active material layer 1132 and the negative electrode active material layer 1142 is stacked is referred to as the active material layer forming portion. In addition, since the main body 111 is elongated cylindrical, the outer surface (outer peripheral surface) of the main body 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.

[0074] The curved portion 1111 is a surface that extends along the X-axis and bends outward in the Z-axis direction (away from the side of the winding axis L). When viewed from the X-axis direction, the curved portion 1111 of this embodiment is curved into a semi-circular arc shape.

[0075] Furthermore, the flat portion 1112 is a flat surface along the XZ plane that extends along the X-axis and connects the ends of a pair of curved portions 1111 to each other. In the main body portion 111, at the location corresponding to the flat portion 1112 (more specifically, the location sandwiched between a pair of flat portions 1112 in the Y-axis direction), multiple electrode plates and diaphragms (positive electrode plate 113 and negative electrode plate 114, diaphragms 115, 116) are stacked in the Y-axis direction.

[0076] It should be noted that the shape of the electrode body 110 is not limited to the wound type, but can also be a stacked type with flat plate electrodes, or a shape in which at least one of the electrode plate and the diaphragm is folded into a corrugated shape (the diaphragm is folded into a corrugated shape and a rectangular electrode plate is sandwiched in it, or the electrode plate and the diaphragm are folded into a corrugated shape in an overlapping state, etc.).

[0077] The container 120 that houses the electrode body 110 configured as described above is, when viewed from the Y-axis direction (the defined horizontal direction), a rectangle with a long dimension in the X-axis direction (a direction orthogonal to the Y-axis and horizontal), and has cutouts (cutouts 131, 132) at least two of the four corners in the Z-axis direction. When viewed from the Y-axis direction, these cutouts at the two corners in the Z-axis direction are formed by inclined surfaces (terminal mounting surfaces) 1211, 1221 extending in inclined directions that intersect the short and long sides of the rectangle, respectively.

[0078] Specifically, container 120 has an external shape (approximately cuboid) based on a cuboid shape that is elongated in the X-axis direction and flattened in the Y-axis direction. For example, in container 120, the dimension in the X-axis direction is more than three times the dimension in the Z-axis direction. It should be noted that... Figure 3 and Figure 6 In the diagram, the rectangular prism shape used as the reference is illustrated by the double-dotted line L1.

[0079] The container 120 of this embodiment, relative to its elongated and flattened cuboid shape in the X-axis direction, has a shape in which a rectangular cut is formed at the upper end (the positive side end in the Z-axis direction) of each end in the X-axis direction. Furthermore, the cut portions 131 and 132 are spaced apart in the X-axis direction at the positive side ends of the container 120 in the Z-axis direction. Electrode terminals 140 are respectively disposed in these cut portions 131 and 132.

[0080] Specifically, the first side end face 121 is the positive side end face of the container 120 in the X-axis direction, having a first upper inclined surface (terminal configuration surface) 1211 and a first side surface 1212, and is elongated in the Z-axis direction when viewed from the X-axis direction.

[0081] The first upper inclined surface 1211 is disposed at the upper end (positive end in the Z-axis direction) of the first side end portion 121, and when viewed from the Y-axis direction, it is a rectangular plane inclined relative to both the X-axis and Z-axis directions. That is, the first upper inclined surface 1211 is a surface that, when viewed from the Y-axis direction, moves from the negative side of the X-axis direction to the positive side of the X-axis direction, and is located from the positive side of the Z-axis direction to the negative side of the Z-axis direction. Furthermore, the first side surface 1212 is a plane extending downward from the lower end of the first upper inclined surface 1211, and is a rectangular plane parallel to the YZ plane with a longer dimension in the Z-axis direction.

[0082] Furthermore, the cut portion 131 of the first side end face 121 is formed by the first upper inclined surface 1211. In other words, the cut portion 131 of the first side end face 121 is a chamfered shape of the corner (corner) of the positive side in the X-axis direction and the positive side in the Z-axis direction of the container 120.

[0083] Additionally, the second side end face 122 is the negative side end face of the container 120 in the X-axis direction, and has a second upper inclined surface (terminal configuration surface) 1221 and a second side surface 1222, with a length dimension in the Z-axis direction when viewed from the X-axis direction.

[0084] The second upper inclined surface 1221 is disposed at the upper end (the positive end in the Z-axis direction) of the second side end portion 122, and when viewed from the Y-axis direction, it is a rectangular plane inclined relative to both the X-axis and Z-axis directions. That is, the second upper inclined surface 1221 is a surface that, when viewed from the Y-axis direction, moves from the positive side in the X-axis direction to the negative side in the X-axis direction, and is located from the positive side in the Z-axis direction to the negative side in the Z-axis direction. Furthermore, the second side surface 1222 is a plane extending downward from the lower end of the second upper inclined surface 1221. In the container 120 of this embodiment, the second upper inclined surface 1221 has the same shape and size as the first upper inclined surface 1211, and the second side surface 1222 has the same shape and size as the first side surface 1212.

[0085] Furthermore, the cut portion 132 of the second side end face 122 is formed by the second upper inclined surface 1221. In other words, the cut portion 132 of the second side end face 122 is a chamfered shape of the corner (corner) of the container 120 on the negative side in the X-axis direction and the positive side in the Z-axis direction.

[0086] Furthermore, in this container 120, the two opposite ends in the Y-axis direction are long side surfaces 123. Each long side surface 123 is a plane parallel to the XZ plane and with a long dimension in the X-axis direction, and its two ends in the X-axis direction are shaped to correspond to the first side surface 121 and the second side surface 122.

[0087] The positive end face in the Z-axis direction of container 120 is the top surface 124, and the negative end face in the Z-axis direction is the bottom surface 125.

[0088] The top surface 124 is a rectangular plane that connects the upper end of the first upper inclined surface 1211 of the first side end face 121 to the upper end of the second upper inclined surface 1221 of the second side end face 122, and is parallel to the XY plane with an elongated dimension in the X-axis direction. The bottom surface 125 is a rectangular plane that connects the lower end of the first side surface 1212 of the first side end face 121 to the lower end of the second side surface 1222 of the second side end face 122, and is parallel to the XY plane with an elongated dimension in the X-axis direction.

[0089] The container body 135 is a portion having a pair of long side surfaces 123, a first side surface 1212, a second side surface 1222, and a bottom surface 125. A container 120 is formed by assembling a cover 136 onto the container body 135 to constitute the energy storage element 10. Furthermore, the cover 136 is a portion having a first upper inclined surface 1211, a second upper inclined surface 1221, and a top surface 124. To ensure insulation from the energy storage elements 10 adjacent to the energy storage element group 3, the surface (outer surface) of the container 120 in this embodiment is covered with an insulating film or other insulating material.

[0090] Specifically, the container body 135 has a flat long sidewall portion with a long side surface 123 at both ends in the Y-axis direction, a rectangular plate-shaped short sidewall portion with a first side surface 1212 or a second side surface 1222 at both ends in the X-axis direction, and a rectangular plate-shaped bottom wall portion with a bottom surface 125 at the negative end in the Z-axis direction.

[0091] The cover 136 is formed by bending the two ends of a plate-shaped component at an angle. Specifically, the cover 136 has a rectangular plate-shaped inclined wall portion with a first upper inclined surface 1211 at the positive end in the X-axis direction, and a rectangular plate-shaped inclined wall portion with a second upper inclined surface 1221 at the negative end in the X-axis direction. In addition, the cover 136 has a rectangular plate-shaped top wall portion with a top surface 124 at the positive end in the Z-axis direction.

[0092] With this structure, the container 120 is configured such that after the electrode body 110 and the like are housed inside the container body 135, the container body 135 and the cover 136 are joined by welding or the like, thereby sealing the interior (housing space S). At this time, in order to prevent short circuits caused by contact between the electrode body 110 and the container body 135 and the cover 136, the electrode body 110 and the like are housed inside the container body 135 after being packaged with a resin film or the like.

[0093] In the container 120, the dimension of the top wall portion (top surface 124) in the X-axis direction is the same as or approximately the same as the dimension of the main body portion 111 of the electrode body 110 in the X-axis direction, and the distance between the top wall portion and the bottom wall portion in the Z-axis direction is the same as or approximately the same as the dimension of the main body portion 111 of the electrode body 110 in the Z-axis direction. Therefore, in the electrode body 110 housed in the container 120 (more specifically, in the housing space S of the container 120), the positive end portion of the main body portion 111 in the Z-axis direction abuts against the top wall portion of the container 120, and the negative end portion of the main body portion 111 in the Z-axis direction abuts against the bottom wall portion of the container 120.

[0094] The material of the container 120 (container body 135 and lid 136) constructed as described above is not limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or coated steel sheet.

[0095] Although not shown in the figure here, the cover 136 has a liquid injection section. This liquid injection section is used to inject electrolyte into the container 120 during the manufacture of the energy storage element 10.

[0096] A pair of electrode terminals 140 (positive terminal 140A and negative terminal 140B) are respectively connected to the electrode body 110 via the current collector 170. The electrode terminals 140 are metallic components used to conduct electricity stored in the electrode body 110 to the external space of the energy storage element 10, and to introduce electricity into the energy storage element 10 for energy storage in the electrode body 110. The material of the electrode terminals 140 is not limited; for example, the electrode terminals 140 (positive terminal 140A and negative terminal 140B) are formed of conductive materials such as aluminum, aluminum alloy, copper, or copper alloy. The electrode terminals 140 are connected (joined) to the current collector 170 by riveting, welding, etc., and are mounted on the cover 136.

[0097] Specifically, each electrode terminal 140 has a terminal body portion 141 disposed outside the container 120 and a shaft portion 145 protruding from the terminal body portion 141 and extending into the interior of the container 120 (within the storage space S). In this embodiment, the electrode terminals 140 are respectively disposed in the cutout portions 131 and 132 of the container 120 (i.e., the first upper inclined surface 1211 and the second upper inclined surface 1221).

[0098] The terminal body 141 is disposed on the first upper inclined surface 1211 (or the second upper inclined surface 1221). In this embodiment, the terminal body 141 is rectangular in shape when viewed from the normal direction. The terminal body 141 is located within the projection area of ​​the first upper inclined surface 1211 (or the second upper inclined surface 1221) in the Z-axis direction and also within the projection area of ​​the first upper inclined surface 1211 (or the second upper inclined surface 1221) in the X-axis direction. That is, the terminal body 141 is located within the cut areas R1 and R2 of the container 120. It should be noted that the cut areas R1 and R2 in this embodiment are... Figure 3 and Figure 6 The region enclosed by the first upper inclined surface 1211 (or the second upper inclined surface 1221) and the double-dotted line L1.

[0099] Furthermore, the terminal body portion 141 has a welding surface 141WS on its surface, which is provided on the first upper inclined surface 1211 (or the second upper inclined surface 1221). In other words, the terminal body portion 141 has a welding surface 141WS on the side opposite to the surface of the electrode terminal 140 where the shaft portion 145 is formed (the surface of the electrode terminal 140 that contacts the recess 150a of the outer washer 150 described later).

[0100] The shaft portion 145 extends into the container 120 through a through hole 1211a (or 1221a) extending along the Z-axis at a location corresponding to the first upper inclined surface 1211 (or the second upper inclined surface 1221) of the cover 136. The shaft portion 145 is riveted to the cover 136, which passes through the outer gasket 150, the cover 136, the inner gasket 160, and the manifold 170 in sequence, thereby connecting (joining) with the manifold 170.

[0101] A pair of external washers 150 are respectively disposed between the container 120 and the electrode terminal 140 (more specifically, the terminal body portion 141) to insulate the container 120 from the electrode terminal 140. In addition, the pair of external washers 150 respectively seal the periphery of the through hole 1211a (or 1221a) of the container 120 and the shaft portion 145 of the electrode terminal 140.

[0102] The outer gasket 150 is formed, for example, 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), polyether sulfone (PES), ABS resin, or a composite material in which fillers have been added.

[0103] Specifically, the outer washer 150 is a plate-shaped component disposed between the first upper inclined surface 1211 (or the second upper inclined surface 1221) and the terminal body portion 141, and is rectangular in shape corresponding to the terminal body portion 141 when viewed from the normal direction. The outer washer 150 has a recess 150a for the terminal body portion 141 to be inserted. The recess 150a is formed on the surface of the terminal body portion 141 opposite to the side of the first upper inclined surface 1211 (or the side of the second upper inclined surface 1221) in the normal direction, and the depth of the recess 150a is smaller than the thickness of the terminal body portion 141. Therefore, when viewed from the Y-axis direction, the terminal body portion 141 protrudes from the outer washer 150 (specifically, the periphery of the recess 150a) (see reference). Figure 6 Additionally, the outer washer 150 has a through hole 150b at a position corresponding to the shaft portion 145 of the electrode terminal 140.

[0104] A pair of internal gaskets 160 are respectively disposed between the container 120 and the current collector 170 to insulate the container 120 from the current collector 170. In addition, the pair of internal gaskets 160 respectively seal the periphery of the through hole 1211a (or 1221a) of the container 120 and the shaft portion 145 of the electrode terminal 140.

[0105] The inner gasket 160 is also the same as the outer gasket 150, for example, formed of electrically insulating resins 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), polyether sulfone (PES), ABS resin, or composite materials in which fillers have been added.

[0106] A pair of current collectors 170 are respectively arranged on both sides of the electrode body 110 in the X-axis direction, and are components that enable the electrode body 110 and the electrode terminal 140 to conduct electricity by connecting (joining) with the electrode body 110 and the electrode terminal 140.

[0107] 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 or riveting, a second joint portion 172 that is connected (joined) to the electrode terminal 140 by riveting or welding, and a connecting portion 173 that connects the first joint portion 171 and the second joint portion 172. These first joint portions 171, second joint portions 172 and connecting portions 173 are all flat plate-shaped parts, formed by bending a sheet of sheet metal.

[0108] It should be noted that the tabs 112 of the electrode body 110 are stacked in the Y-axis direction and have a front end protruding from the main body 111 in the X-axis direction, while the first engagement portion 171 that engages with the tabs 112 is a plate-like member that extends in the YZ plane. Therefore, it is difficult to engage the tabs 112 and the first engagement portion 171 when the front end of the tabs 112 is only in contact with the first engagement portion 171 in the X-axis direction. Therefore, in this embodiment, by engaging the tabs 112 of the electrode body 110 with the current collector 170 while the tabs 112 are bent in the Y-axis direction, the tabs 112 and the first engagement portion 171 can be reliably engaged, and the electrode body 110 and the current collector 170 can be compactly housed inside the container 120.

[0109] The material of the current collector 170 is not limited. For example, the positive current collector 170A and the positive current collector foil 1131 of the electrode body 110 are both formed of conductive components such as aluminum or aluminum alloy, and the negative current collector 170B and the negative current collector foil 1141 of the electrode body 110 are both formed of conductive components such as copper or copper alloy.

[0110] The energy storage elements 10 configured as described above are arranged in the energy storage element group 3 with the corresponding electrode terminals 140 of adjacent energy storage elements 10 having different polarities (i.e., adjacent electrode terminals 140 to each other). That is, multiple energy storage elements 10 are arranged in the Y-axis direction with their two ends in the X-axis direction alternately flipped. At this time, the long sides 123 of adjacent energy storage elements 10 are facing each other. In addition, at both ends of the energy storage element group 3 in the X-axis direction, the cutouts 131, 132 of each energy storage element 10 are arranged alternately in the Y-axis direction.

[0111] The energy storage element group 3 is housed in the storage space S of the housing 20 with the first side surface 1212, second side surface 1222, top surface 124, and bottom surface 125 of each energy storage element 10 contained therein in contact with the corresponding cooling surfaces 20CS of the housing 20 (in this embodiment, the second side wall 232, fourth side wall 234, bottom wall 22, and inner surfaces 20S of the housing 20 and the housing cover 25) of the housing 20. (Refer to...) Figure 7 In addition, the energy storage element group 3 is housed in the storage space S of the housing 20 with the long side surface 123 of each energy storage element 10 located at both ends in the Y-axis direction contacting the corresponding inner surface 20S of the housing 20 (in this embodiment, the inner surfaces 20S of the first side wall 231 and the third side wall 233) respectively.

[0112] In this way, the energy storage element group 3 is housed in the housing 20 such that each surface (first side surface 1212, second side surface 1222, top surface 124, bottom surface 125) of each energy storage element 10 constituting the energy storage element group 3 is in contact with the corresponding inner surface 20S of the housing 20. This forms a first space S1 at the corner of the housing 20 on the positive side in the X-axis direction and the positive side in the Z-axis direction, and a second space S2 at the corner of the housing 20 on the negative side in the X-axis direction and the positive side in the Z-axis direction (see reference). Figure 7 ).

[0113] The first space S1 and the second space S2 extend along the Y-axis from the inner surface 20S of the first sidewall 231 to the inner surface 20S of the third sidewall 233 inside the housing 20. Furthermore, a busbar 30 is disposed in these first spaces S1 and second spaces S2.

[0114] Multiple busbars 30 respectively connect the corresponding electrode terminals 140 of adjacent energy storage elements 10 to each other (specifically, the positive terminal 140A and negative terminal 140B of adjacent energy storage elements 10). Thus, multiple energy storage elements 10 are connected in series in the energy storage element group 3. The busbar 30 is formed of conductive parts made of metals such as aluminum, aluminum alloy, copper, copper alloy, nickel, or combinations thereof, or conductive parts other than metals.

[0115] Specifically, the busbar 30 is a plate-shaped portion extending along the first upper inclined surface 1211 (or the second upper inclined surface 1221) and having an elongated dimension in the Y-axis direction. The Y-axis dimension of the busbar 30 overlaps with the dimension of two adjacent terminal body portions 141 in the energy storage element group 3 in the Y-axis direction. In other words, the busbar 30 is configured to cover the surfaces of each terminal body portion 141 across the positions of the two adjacent energy storage elements in the Y-axis direction. It should be noted that the busbar 30 may completely cover the surface of each terminal body portion 141, or it may only partially cover the surface of the terminal body portion 141, leaving a portion of the terminal body portion 141 exposed.

[0116] Each busbar 30 is soldered to the soldering surface 141WS of the terminal body 141 of each terminal body 141 relative to the two corresponding electrode terminals 140 of the adjacent energy storage element 10 of the energy storage element group 3 (i.e., the positive terminal 140A and the negative terminal 140B adjacent in the Y-axis direction), thereby connecting (conducting) the two electrode terminals 140A and 140B. In addition, when the energy storage element group 3 is viewed from the Y-axis direction, each busbar 30 is located in the first space S1 or the second space S2 (i.e., the cut-out areas R1 and R2 connected in the Y-axis direction) (see reference). Figure 7It should be noted that in this embodiment, the busbar 30 is illustrated as a plate, and the surfaces of the electrode terminals 140A and 140B are also illustrated as flat plates, but this structure is not limited to this. Alternatively, at the junction of the busbar 30 and the electrode terminals 140A and 140B, the busbar 30 may have a hole, and the electrode terminals 140A and 140B may have protrusions that engage with the hole in the busbar 30. Furthermore, the electrode terminals 140A and 140B may have a bolt portion and a nut portion, with the nut portion screwed into the bolt portion when the bolt portion is inserted through the hole in the busbar 30 (i.e., the busbar 30 is fastened by the bolt portion and the nut portion).

[0117] It should be noted that in the energy storage device 1 of this embodiment, the positive terminal 140A of the energy storage element 10 on the positive side in the Y-axis direction of the energy storage element group 3 is connected to the first main terminal 235 via the main terminal line, and the negative terminal 140B of the energy storage element 10 on the negative side in the Y-axis direction of the energy storage element group 3 is connected to the second main terminal 236 via the main terminal line.

[0118] The energy storage device 1 described above includes an energy storage element 10 comprising: an electrode body 110 having multiple electrode plates 113 and 114 stacked on top of each other; a container 120 for housing the electrode body 110; and a pair of electrode terminals 140 that are in communication with the electrode body 110. Furthermore, the container 120, when viewed from the Y-direction (first direction), which is a defined horizontal direction, is a rectangle with a long dimension in the X-direction (second direction), which is orthogonal to the Y-axis. It is a rectangle with cutouts at least on two corners of one side in the vertical direction. When viewed from the Y-axis, the cutouts are formed by a first upper inclined surface (terminal mounting surface) 1211 or a second upper inclined surface (terminal mounting surface) 1221 extending along inclined directions that intersect the short and long sides of the rectangle. The electrode terminals 140 are respectively disposed on the first upper inclined surface (terminal mounting surface) 1211 or the second upper inclined surface (terminal mounting surface) 1221.

[0119] According to one embodiment of the present invention, an energy storage element 10 has electrode terminals 140 arranged along a first upper inclined surface 1211 or a second upper inclined surface 1221 provided at the two corners of a rectangle when viewed from the Y-axis direction. Therefore, it is possible to suppress the unused space caused by the protrusion of the electrode terminals 140 when the energy storage element 10 is housed in the housing portion 2 (see reference). Figure 7 This allows for an increase in the energy density of the energy storage device 1 when the energy storage element 10 is housed in the housing portion 2.

[0120] Furthermore, in the energy storage device 1 of this embodiment, the electrode terminals 140 are located within the projection area of ​​the first upper inclined surface (terminal mounting surface) 1211 or the second upper inclined surface (terminal mounting surface) 1221 in the Z-axis direction and within the projection area of ​​the first upper inclined surface 1211 or the second upper inclined surface 1221 in the X-axis direction (i.e., within the cut areas R1 and R2). Therefore, when multiple energy storage elements 10 are arranged along the Y-axis direction, contact between the electrode terminals 140 of adjacent energy storage elements 10 can be suppressed. In addition, when multiple energy storage elements 10 are arranged along the Y-axis direction, protrusion of the electrode terminals 140 of each energy storage element 10 in the Z-axis direction when viewed from the Y-axis direction, and protrusion of the electrode terminals 140 from the two end edges of each energy storage element 10 in the X-axis direction can also be suppressed.

[0121] In addition, the energy storage device 1 of this embodiment includes a plurality of energy storage elements 10 arranged along the Y-axis direction and at least one busbar 30 that makes the corresponding electrode terminals 140 of adjacent energy storage elements 10 interconnected. The corresponding first upper inclined surface (terminal arrangement surface) 1211 and second upper inclined surface (terminal arrangement surface) 1221 of adjacent energy storage elements 10 are arranged in the Y-axis direction along an imaginary surface that extends in the inclined direction (the direction along the first upper inclined surface 1211 and the second upper inclined surface 1221 when viewed from the Y-axis direction) and the Y-axis direction.

[0122] Thus, in the energy storage device 1 of this embodiment, electrode terminals 140 are arranged along the first upper inclined surface 1211 or the second upper inclined surface 1221, which are provided at the two corners of the rectangle when viewed from the Y-axis direction of the container 120. Therefore, it is possible to suppress the useless space caused by the protrusion of the electrode terminals 140 when multiple energy storage elements 10 are housed in the housing portion 2. As a result, the energy density of the energy storage device 1 can be improved.

[0123] Furthermore, the energy storage device 1 of this embodiment includes a housing portion (element container) 2 with at least one of its multiple inner surfaces 20S that define an internal storage space S as a cooling surface 20CS. The housing portion 2 houses the energy storage element group 3, which includes multiple energy storage elements 10 and at least one busbar 30, in contact with the cooling surface 20CS. Therefore, the energy storage element group 3 housed in the housing portion 2 is cooled by contact with the cooling surface 20CS, thereby suppressing the temperature rise of the energy storage element group 3 during charging and discharging.

[0124] Furthermore, in the energy storage device 1 of this embodiment, when viewed from the Y-axis direction, the busbar 30 is located within the projection area of ​​the first upper inclined surface (terminal mounting surface) 1211 or the second upper inclined surface (terminal mounting surface) 1221 towards the Z-axis direction (vertical direction) and within the projection area of ​​the first upper inclined surface 1211 or the second upper inclined surface 1221 towards the second direction (i.e., within the cutout areas R1 and R2). Therefore, in the energy storage element group 3, when viewed from the Y-axis direction, the busbar 30 does not protrude outward in the X-axis direction or in the Z-axis direction. As a result, the generation of useless space in the storage space S of the housing portion 2 caused by the protrusion of the busbar 30 can be suppressed (for example, see reference). Figure 7 On the other hand, when the storage space S is too large, it leads to a reduction in the effective electrode area in the electrode body 110 within the energy storage element 10, resulting in a decrease in the energy density of the energy storage device 1. Therefore, it is important to design a storage space S of an appropriate size. In addition, the appropriate size of this storage space S varies depending on the size and capacity of the energy storage element 10, the size of the electrode terminal 140, the size of the busbar 30, etc.

[0125] Furthermore, when multiple energy storage elements 10 are housed in the housing portion 2, laser light can be irradiated from the upper surface of the multiple energy storage elements 10 during laser welding of the electrode terminals 140 of the energy storage elements 10 to the busbar 30. This simplifies the welding process of the busbar to the multiple energy storage elements 10 and enables a low-resistance connection structure with a large contact area between the busbar 30 and the electrode terminals 140 and a large area of ​​the busbar 30.

[0126] It should be noted that the energy storage element and energy storage device of the present invention are not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the structure of another embodiment can be added to the structure of a certain embodiment; in addition, a part of the structure of a certain embodiment can be replaced with the structure of another embodiment. Furthermore, a part of the structure of a certain embodiment can be deleted.

[0127] In the energy storage device 1 of the above embodiment, an example is shown where each energy storage element 10 constituting the energy storage element group 3 is connected in series via a busbar 30, but the device is not limited to this structure. Each energy storage element 10 constituting the energy storage element group 3 may also be connected in parallel via the busbar 30.

[0128] Specifically, parallel connections can also be made within the energy storage element group 3. In this case, energy storage elements with the same polarity as each other (i.e., adjacent electrode terminals 140) of adjacent energy storage elements 10 can be arranged along the Y-axis direction, and adjacent energy storage elements 10 can be connected to each other using the bus bar 30.

[0129] In addition, at this time, the busbar 30 connection between the energy storage elements 10 is not only between adjacent energy storage elements 10, but may also be a case where multiple energy storage elements 10 are connected through a busbar 30.

[0130] Furthermore, this embodiment illustrates a case where only one energy storage element group 3 is housed within the housing 20, but multiple energy storage element groups 3 can also be housed. Additionally, a separation structure can be provided between multiple energy storage element groups 3. Moreover, regarding the electrical connection between the multiple battery element groups 3, they can be connected in series or in parallel.

[0131] In the energy storage element 10 of the above embodiment, the cutouts 131 and 132 with electrode terminals 140 are located at the upper two corners of the four corners when the container 120 is viewed from the Y-axis direction, but this structure is not limited to this. The cutouts 131 and 132 with electrode terminals 140 may also be located at the lower two corners of the four corners when the container 120 is viewed from the Y-axis direction.

[0132] Furthermore, in the energy storage element 10 of the above embodiment, the positive side cutout 131 and the negative side cutout 132 in the X-axis direction have the same shape and size, but they can also be different. That is, the tilt angles of the first upper inclined surface 1211 and the second upper inclined surface 1221 relative to the Z-axis direction can also be slightly different. Specifically, the difference in tilt angle is only necessary to the extent that it does not cause problems when the busbar is soldered between the electrode terminals 140.

[0133] Furthermore, in the energy storage element 10 of the above embodiment, the container 120 has a rectangular shape when viewed from the X-axis direction, but it is not limited to this structure. For example, the container 120A may also be as follows: Figure 8 The shape shown is oblong when viewed from the X-axis. That is, the container 120A can also be based on a flat oblong cylindrical shape. According to this structure, the container 120A is shaped along the outer surface of the electrode body 110. Compared with a square container, the useless space (residual space) inside the container 120A is suppressed, and the energy density inside the container 120A of the energy storage element 10A is increased.

[0134] Specifically, in container 120A, the top surface 124A, when viewed from the X-axis, is an upward-convex arc shape, and the bottom surface 125A, when viewed from the X-axis, is a downward-convex arc shape. Furthermore, container 120, when viewed from the X-axis, is not limited to a rectangle or an oblong shape. When viewed from the X-axis, container 120 can also be a circle or a polygon, etc. That is, when viewed from the Y-axis, container 120 only needs to be a rectangle with a longer dimension in the X-axis direction and have cutouts at two corners on one side of the Z-axis direction.

[0135] Furthermore, the specific shape of each terminal body portion 141 is not limited. Each terminal body portion 141 in the above embodiment is rectangular when viewed from the normal direction of the welding surface 141WS, but it may also be circular, oblong, elliptical, etc.

[0136] In addition, in the energy storage element group 3 of the above embodiment, a plurality of energy storage elements 10 are arranged in such a way that adjacent energy storage elements 10 are connected to each other, but spacers, insulating parts, etc. may also be arranged between adjacent energy storage elements 10 in the Y-axis direction.

[0137] Furthermore, the housing body 21 in the above embodiment is a bottomed rectangular cylindrical component with a height in the Z-axis direction capable of accommodating the energy storage element 10 and having an opening 21A. The housing cover 25 has been described as a rectangular plate-like component extending in the X and Y axes, but this embodiment is not limited to this. The housing cover 25 may not be a plate-like component consisting of only one plate, but may be a bottomed rectangular cylindrical component with four sidewalls continuously provided in the circumferential direction along the periphery, similar to the housing body 21, and with its bottom arranged opposite to the housing body 21 in the Z-axis direction. In other words, the housing cover 25 may also be a square (box-shaped) component with a plate-like component on the positive side in the Z-axis direction as its top surface, sidewalls arranged from this top surface along the Z-axis direction, and an opening on the negative side in the Z-axis direction.

[0138] While using the modified example of the shell cover described above, by making the height of the side wall of the shell body 21 more than... Figure 2 The shown form is low-profile, allowing for the combination of the main body 21 and the modified cover of the shell to form an upper shell and a lower shell, thus constituting a shell 20. Figure 2 In the housing body 21 shown, the height of the inner wall of the first to fourth side walls 231 to 234 in the Z-axis direction is set to half the height of the energy storage element 10 in the Z-axis direction, and the housing body 21 can accommodate the lower half of the energy storage element 10 in the Z-axis direction. Furthermore, in a modified example of the housing cover, the height of the inner wall of the side wall in the Z-axis direction is set to half the height of the energy storage element 10 in the Z-axis direction, and the housing cover can accommodate the upper half of the energy storage element 10 in the Z-axis direction. It should be noted that it is possible to appropriately choose not to divide the height exactly in half, but rather to set the height of one side and the other side in the Z-axis direction as... Figure 2The height is one-third or two-thirds of the overall height in the Z-axis direction. In this case, the terminal portion 140 of the energy storage element 10 and the connecting portion of the busbar 30 can also be accommodated in the internal space of the modified example of the housing cover (upper housing). With such a structure for the upper and lower housings, when the busbar 30 is welded to the terminal portion 140 of the energy storage element 10, the side wall of the housing body 21 (lower housing) does not interfere with the terminal portion 140 and the busbar 30, thus improving the workability of welding the busbar 30.

[0139] It should be noted that in the above embodiment, the refrigerant pipe 26 has one system of piping on each surface of the housing 20, and four systems of piping are arranged on the four surfaces of the housing 20. However, this embodiment is not limited to this. The refrigerant pipe 26 can also be arranged to cover both surfaces of the housing 20 by bending from the first surface to the second surface.

[0140] Explanation of reference numerals in the attached figures

[0141] 1: Energy storage device; 2: Housing (component container); 20: Housing; 20CS: Cooling surface; 20S: Inner surface; 21: Housing body; 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: Housing cover; 26: Refrigerant pipe; 3: Energy storage element group; 30: Busbar; 10, 10A: Energy storage element; 110: Electrode body; 111: Main body; 1111: Bending part ; 1112: Flat portion; 112: Tab portion; 112a: Positive tab portion; 112b: Negative tab portion; 113: Positive electrode plate; 1131: Positive current collector foil; 1132: Positive active material layer; 1133: Protruding piece; 114: Negative electrode plate; 1141: Negative current collector foil; 1142: Negative active material layer; 1143: Protruding piece; 115, 116: Separator; 120, 120A: Container; 121: First side end portion; 1211: First upper inclined surface (terminal mounting surface); 1211a: Through hole ; 1212: First side surface; 122: Second side end face; 1221: Second upper inclined surface (terminal mounting surface); 1222: Second side surface; 123: Long side surface; 124, 124A: Top surface; 125, 125A: Bottom surface; 131, 132: Cutout; 135: Container body; 136: Cover; 140: Electrode terminal; 140A: Positive terminal; 140B: Negative terminal; 141: Terminal body; 141WS: Welding surface; 145: Shaft; 150: External washer; 150a: Recess; 150b: Through-hole Hole; 160: Internal gasket; 170: Current collector; 170A: Positive current collector; 170B: Negative current collector; 171: First joint; 172: Second joint; 173: Connecting part; 500: Secondary battery; 501: Battery casing; 502: Casing body; 503: Cover; 504: Positive terminal; 505: Negative terminal; 506: Component container; 507: Energy storage device; B: Busbar; DS: Unused space; L: Winding shaft; R1, R2: Cut-out areas; S: Storage space; S1: First space; S2: Second space.

Claims

1. An energy storage element, comprising: An electrode body, which consists of multiple stacked electrode plates; A container that houses the electrode body; and A pair of electrode terminals, which are in communication with the electrode body. Viewed from a first direction, which is defined as a horizontal direction, the container is a rectangle with a longer dimension in a second direction orthogonal to the first direction and horizontal, and is a rectangle with cutouts at least on two corners on one side in the vertical direction. The cutout shapes are each formed by terminal mounting surfaces, which are arranged in an inclined direction in the rectangle as viewed from the first direction, intersecting the long side of one side of the vertical direction and the short side of one side of the rectangle in the second direction or the short side of the rectangle in the other side of the second direction. The electrode terminals are respectively disposed on the terminal configuration surface.

2. The energy storage element according to claim 1, The electrode terminal is located within the projection area of ​​the terminal configuration surface in the vertical direction and within the projection area of ​​the terminal configuration surface in the second direction.

3. The energy storage element according to claim 1, The electrode body is constructed by winding the electrode plates in an oblong shape when viewed from the second direction. When viewed from the second direction, the container appears as an elongated oval shape corresponding to the electrode body.

4. An energy storage device, comprising: The energy storage elements according to any one of claims 1 to 3, arranged in the first direction; and At least one busbar that connects the corresponding electrode terminals of adjacent energy storage elements to each other. The corresponding terminal configuration surfaces of the adjacent energy storage elements are arranged in the first direction along a common imaginary surface that extends in both the inclined direction and the first direction.

5. The energy storage device according to claim 4, The component container has at least one of its multiple inner surfaces that define an internal storage space as a cooling surface. The component container houses the energy storage element group in such a manner that the energy storage element group, which includes the plurality of energy storage elements and the at least one busbar, is in contact with the cooling surface.

6. The energy storage device according to claim 5, Viewed from the first direction, the busbar is located within the projection area of ​​the terminal configuration surface in the vertical direction and within the projection area of ​​the terminal configuration surface in the second direction.

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