Power storage device

Abstract

This power storage device comprises a first power storage element and a second power storage element, and a bus bar that connects the first power storage element and the second power storage element, wherein: the second power storage element is disposed on one side of the first power storage element in a first direction; the first power storage element includes a first terminal disposed on the one side in the first direction; the second power storage element includes a second terminal disposed on the other side in the first direction; the bus bar includes a first part connected to the first terminal, a second part connected to the second terminal, and an intermediate part that connects the first part and the second part; and the intermediate part includes a bent portion that is convex in a second direction intersecting the first direction.

Description

Power storage device

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

[0002] Patent Document 1 discloses an assembled battery including a plurality of thin batteries. The thin battery is composed of four positive electrode plates, nine separators, four negative electrode plates, a positive electrode terminal, a negative electrode terminal, an upper battery exterior, and a lower battery exterior. The positive electrode terminal is led out from one end of the upper battery exterior and the lower battery exterior. The negative electrode terminal is led out from the other end of the upper battery exterior and the lower battery exterior.

[0003] Japanese Unexamined Patent Application Publication No. 2004-14317

[0004] In the above conventional assembled battery, a plurality of thin batteries are stacked in the vertical direction. Therefore, there is a problem that as the number of thin batteries increases, the vertical length (height) of the assembled battery increases. In order to solve this problem, it is conceivable to arrange a plurality of thin batteries in the arrangement direction of the positive electrode terminal and the negative electrode terminal in one thin battery. However, in this case, the positive electrode terminal of one of the two adjacent thin batteries abuts against the negative electrode terminal of the other thin battery. When the positive electrode terminal and the negative electrode terminal are connected by welding or the like in a state where they are abutted, welding or the like is performed from a direction orthogonal to the direction in which the positive electrode terminal and the negative electrode terminal face each other. Therefore, it is difficult to ensure the reliability of the connection portion between the positive electrode terminal and the negative electrode terminal.

[0005] The present invention has been made by the inventors of the present application newly paying attention to the above problems, and aims to provide a power storage device with improved reliability.

[0006] An energy storage device according to one aspect of the present invention comprises a first energy storage element and a second energy storage element, and a busbar connecting the first energy storage element and the second energy storage element, wherein the second energy storage element is located on one side of the first energy storage element in a first direction, the first energy storage element has a first terminal located on the one side of the first direction, the second energy storage element has a second terminal located on the other side of the first direction, and the busbar comprises a first part connected to the first terminal, a second part connected to the second terminal, and an intermediate part connecting the first part and the second part, wherein the intermediate part has a bent portion that protrudes in a second direction intersecting the first direction.

[0007] According to the present invention, an energy storage device with improved reliability can be provided.

[0008] Figure 1 is a perspective view showing the external appearance of an energy storage device according to an embodiment. Figure 2 is an exploded perspective view of an energy storage device according to an embodiment. Figure 3 is a schematic cross-sectional view showing the internal configuration of an energy storage element according to an embodiment. Figure 4 is a schematic cross-sectional view showing the configuration of the busbar and its surroundings in an energy storage device according to an embodiment. Figure 5 is a side view showing an example of the shape of the intermediate part of the busbar according to an embodiment. Figure 6 is a simplified side view showing the configuration of the energy storage device before bending work on the busbar begins. Figure 7 is a simplified side view showing the configuration of the energy storage device after bending work on the busbar has begun but before it is completed. Figure 8 is a schematic cross-sectional view showing the configuration of the busbar and its surroundings in an energy storage device according to a modified example of the embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention comprises a first energy storage element and a second energy storage element, and a busbar connecting the first energy storage element and the second energy storage element, wherein the second energy storage element is located on one side of the first energy storage element in a first direction, the first energy storage element has a first terminal located on one side of the first direction, the second energy storage element has a second terminal located on the other side of the first direction, and the busbar comprises a first part connected to the first terminal, a second part connected to the second terminal, and an intermediate part connecting the first part and the second part, wherein the intermediate part has a bent portion that protrudes in a second direction intersecting the first direction.

[0010] According to one aspect of the present invention, the first and second energy storage elements are provided with terminals in the direction in which they are aligned (first direction), so that the height of the energy storage device in the vertical direction can be made relatively low when the first and second energy storage elements are arranged horizontally. Furthermore, the first and second terminals, which face each other, are connected by a busbar having a bent portion that protrudes in the second direction intersecting the first direction. In other words, the busbar can be connected to the first and second terminals by welding or the like. Therefore, the reliability of the connection between the first and second terminals is higher than when the first and second terminals are butted together and connected by welding or the like. Accordingly, the energy storage device according to this aspect is an energy storage device with improved reliability.

[0011] (2) In the energy storage device described in (1) above, the first part and the second part may be arranged between the first terminal and the second terminal.

[0012] According to the energy storage device described in (2) above, the first and second parts of the busbar are positioned between two terminals and connected by an intermediate part having a bent portion that protrudes in the second direction. Therefore, for example, a simple U-shaped portion can be made into a busbar using a conductor.

[0013] (3) In the energy storage device described in (2) above, the first part and the second part may be in contact with each other in the first direction.

[0014] According to the energy storage device described in (3) above, since the first and second parts of the busbar are in contact in the first direction, the formation of a gap between the first and second parts is suppressed. This suppresses the increase in the size of the energy storage device in the first direction caused by connecting the first and second energy storage elements with a busbar.

[0015] (4) In the energy storage device described in any one of (1) to (3) above, the bent portion may include a thin-walled portion extending in a third direction intersecting the first direction and the second direction.

[0016] According to the energy storage device described in (4) above, the busbar before bending has a thin-walled portion extending in a third direction. Therefore, the bent portion can be formed accurately and / or efficiently using the position of the thin-walled portion as a reference.

[0017] (5) The energy storage device described in any one of (1) to (4) above may further include a wiring member arranged in the intermediate part.

[0018] According to the energy storage device described in (5) above, the intermediate portion, which is not directly connected to the terminals of the energy storage element, can be effectively used as a portion for arranging wiring members used, for example, for detecting temperature or voltage.

[0019] (6) In the energy storage device described in any one of (1) to (5) above, the first terminal may have a first connection surface to which the first part is connected, the second terminal may have a second connection surface to which the second part is connected, and the first connection surface and the second connection surface may face each other in the first direction.

[0020] According to the energy storage device described in (6) above, the first connection surface and the second connection surface face each other in the direction of alignment of the first energy storage element and the second energy storage element. Therefore, a busbar having an intermediate portion including a bent portion can be obtained, for example, by bending a plate-shaped member in the thickness direction. In other words, a busbar can be realized with a simple U-shaped conductor.

[0021] The following description of an energy storage device according to embodiments and modifications thereof of the present invention will be given with reference to the drawings. The embodiments and modifications described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, manufacturing processes, and the order of manufacturing processes shown in the following embodiments and modifications are examples only and are not intended to limit the present invention. In addition, dimensions and other specifications in each figure are not strictly illustrated. In each figure, the same or similar components are denoted by the same reference numerals.

[0022] In the following description and drawings, the direction in which the first and second energy storage elements are aligned, the direction in which the first and second connection parts of the electrode body are aligned, or the direction in which the two short sides of the energy storage element container are aligned is defined as the X-axis direction. The direction in which the pair of long sides of the energy storage element container are aligned, or the thickness direction of the container or electrode body is defined as the Y-axis direction. The direction in which the first and second parts of the busbar extend, the direction in which the intermediate part of the busbar is aligned with the first or second part, or the longitudinal direction of the short side of the container is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Depending on the usage, the Z-axis direction may not be vertical, but for the sake of explanation below, the Z-axis direction will be described as vertical.

[0023] In the following explanation, the X-axis positive direction refers to the direction of the X-axis arrow, and the X-axis negative direction refers to the opposite direction. The same applies to the Y-axis and Z-axis directions. When simply referred to as "X-axis direction," it means either the bidirectional or unidirectional direction parallel to the X-axis. The same applies to the terminology related to the Y-axis and Z-axis.

[0024] Furthermore, expressions indicating relative directions or orientations, such as parallel and orthogonal, may not strictly include cases where the directions or orientations are not actually those directions or orientations. Two directions being orthogonal does not only mean that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, i.e., include a difference of a few percent. In the following explanation, when "insulation" is used, it means "electrical insulation." The volume resistivity of an insulating material is 1 × 10⁻⁶. ６ Preferably Ωm or more, 1 × 10 ７ Ωm or greater is more preferable, 1 × 10 １０ A value of Ωm or greater is even more preferable.

[0025] (Embodiment) [1. General Description of Energy Storage Device 1] First, a general description of the energy storage device 1 in this embodiment will be given using Figures 1 to 3. Figure 1 is a perspective view showing the external appearance of the energy storage device 1 according to the embodiment. Figure 2 is an exploded perspective view of the energy storage device 1 according to the embodiment. Figure 3 is a schematic cross-sectional view showing the internal configuration of the energy storage element 10 according to the embodiment. In Figure 3, a cross-section of the energy storage element 10 is simply shown, which is parallel to the XZ plane passing through the line III-III in Figure 2.

[0026] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to an external source. The energy storage device 1 is a battery module (battery pack) used for power storage or power supply purposes. Specifically, the energy storage device 1 is used as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, automated guided vehicles (AGVs), or railway vehicles for electric railways. Examples of automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of railway vehicles for electric railways include electric trains, monorails, maglev trains, and hybrid trains equipped with both diesel engines and electric motors. The energy storage device 1 can also be used as a stationary battery for household or commercial use.

[0027] As shown in Figures 1 and 2, the energy storage device 1 comprises two energy storage elements 10 and a busbar 700. The energy storage device 1 according to this embodiment may comprise three or more energy storage elements 10 and two or more busbars 700, but in the following description, we will focus on the two energy storage elements 10 and one busbar 700 shown in Figures 1 and 2. In addition to the energy storage elements 10 and the busbar 700, the energy storage device 1 may also comprise a control device for controlling the charging and discharging of the multiple energy storage elements 10, and an outer casing that forms the outer shell of the energy storage device 1.

[0028] The configuration of the energy storage element 10 described below applies to both of the two energy storage elements 10 provided in the energy storage device 1. When distinguishing between these two energy storage elements 10, the energy storage element 10 in the negative X-axis direction is referred to as the first energy storage element 10A, and the energy storage element 10 in the positive X-axis direction is referred to as the second energy storage element 10B.

[0029] The energy storage device 1 according to this embodiment includes an energy storage element 10, which is a secondary battery, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 may be a secondary battery other than a non-aqueous electrolyte secondary battery, or it may be a capacitor. The energy storage element 10 may be a primary battery. The energy storage element 10 may be a pouch-type energy storage element. The energy storage element 10 may be a battery using a solid electrolyte.

[0030] As shown in Figures 1 and 2, the energy storage element 10 comprises a container 100 that is flattened in the Y-axis direction, a first terminal 200, and a second terminal 250. As shown in Figure 3, an electrode body 600 is housed inside the container 100. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but it is not shown in the illustration. There are no particular restrictions on the type of electrolyte as long as it does not impair the performance of the energy storage element 10, and various types can be selected. Furthermore, spacers and insulating films, etc., which are not shown, may be arranged inside the container 100.

[0031] As shown in Figures 1 to 3, the container 100 is a rectangular parallelepiped (box-shaped) case. A rectangular parallelepiped, in this context, is a hexahedron whose faces are all rectangles or squares. The container 100 has a pair of long sides 101 aligned in the Y-axis direction, a pair of short sides 102 aligned in the X-axis direction, a top surface 103 which is in the positive XZ-axis direction, and a bottom surface 104 which is in the negative Z-axis direction. In this embodiment, of the six sides of the container 100, the long side 101 has the largest area, and the short side 102 has the smallest area. The area of ​​the top surface 103 and the bottom surface 104 is larger than the short side 102 and smaller than the long side 101. The X-axis direction is an example of a first direction, the Z-axis direction is an example of a second direction, and the Y-axis direction is an example of a third direction.

[0032] In this embodiment, the container 100 comprises a container body 130 and lid plates 110 and 120. The container body 130 is a rectangular cylindrical member and comprises a first opening 131 that opens on one side in the X-axis direction (in this embodiment, the positive X-axis direction) and a second opening 132 that opens on the other side in the X-axis direction (in this embodiment, the negative X-axis direction). The first opening 131 is closed by the lid plate 110, and the second opening 132 is closed by the lid plate 120.

[0033] In container 100, the pair of long sides 101, the top surface 103, and the bottom surface 104 are formed by the container body 130. In container 100, the short side 102 in the positive X-axis direction is formed by the lid plate 110, and the short side 102 in the negative X-axis direction is formed by the lid plate 120.

[0034] The lid plate 110 is a plate-shaped member formed to the size and shape necessary to close the first opening 131 of the container body 130. A first terminal 200 is positioned on the lid plate 110. More specifically, the energy storage element 10 according to this embodiment includes a first terminal 200 fixed to the lid plate 110 via an insulating member 220. The first terminal 200 is electrically connected to the second connection portion 620 of the electrode body 600 via a current collector 500. The insulating member 220 has a first insulating member 230 and a second insulating member 240. The first terminal 200 has a terminal body 201 and a shaft portion 210. The terminal body 201 is positioned on the short side 102 formed by the lid plate 110 via the first insulating member 230.

[0035] In this configuration, the shaft portion 210 of the first terminal 200 is crimped at its tip while passing through the first insulating member 230, the cover plate 110, the second insulating member 240, and the current collector 500. This forms a crimped portion 211 at the tip of the shaft portion 210. As a result, the first terminal 200 is fixed to the cover plate 110 together with the first insulating member 230, the second insulating member 240, and the current collector 500. In other words, the first terminal 200 and the current collector 500 are connected by crimping the tip of the shaft portion 210. There are no particular limitations on the method of connecting the first terminal 200 and the current collector 500. The first terminal 200 and the current collector 500 may be connected by welding or by bolt and nut joining, etc. Furthermore, the second connection portion 620 of the electrode body 600 and the current collector 500 are connected by ultrasonic bonding, etc. As a result, the second connection portion 620 of the electrode body 600 and the first terminal 200, which is insulated from the container 100 by the insulating member 220, are electrically connected via the current collector 500. There are no particular limitations on the method of connecting the current collector 500 and the second connection portion 620. Laser welding or crimping may be used as the method of connecting the current collector 500 and the second connection portion 620. In this embodiment, the first terminal 200 and the current collector 500 are formed of conductive materials such as aluminum, aluminum alloy, copper, or copper alloy.

[0036] The lid plate 120 is a plate-shaped member formed to the size and shape necessary to close the second opening 132 of the container body 130. A second terminal 250 is positioned on the lid plate 120. More specifically, the energy storage element 10 according to this embodiment includes a second terminal 250 fixed to the lid plate 120 via an insulating member 220. The second terminal 250 is electrically connected to the first connection portion 610 of the electrode body 600 via a current collector 550. The insulating member 220 has a first insulating member 230 and a second insulating member 240. The second terminal 250 has a terminal body 251 and a shaft portion 260. The terminal body 251 is positioned on the short side 102 formed by the lid plate 120 via the first insulating member 230.

[0037] The manner in which the second terminal 250 and the electrode body 600 are connected is the same as the manner in which the first terminal 200 and the electrode body 600 are connected. That is, the second terminal 250 is fixed to the cover plate 120 by forming a crimped portion 261 at the tip of the shaft portion 260 of the second terminal 250, and the second terminal 250 is connected to the current collector 550. Furthermore, the first connection portion 610 of the electrode body 600 and the current collector 550 are connected by ultrasonic bonding or the like. As a result, the first connection portion 610 of the electrode body 600 and the second terminal 250, which is insulated from the container 100 by the insulating member 220, are electrically connected via the current collector 550. There are no particular limitations on the method of connecting the second terminal 250 and the current collector 550, or the method of connecting the current collector 550 and the first connection portion 610. In this embodiment, the second terminal 250 and the current collector 550 are formed of a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0038] In Figure 3, the first terminal 200 is shown as a single component comprising the terminal body 201 and the shaft portion 210. However, the first terminal 200 may also be formed by connecting the terminal body 201 and the shaft portion 210, which are separate components, by press-fitting, fitting, crimping, or welding. The same applies to the second terminal 250; the second terminal 250 may be formed by connecting the terminal body 251 and the shaft portion 260, which are separate components, by press-fitting, fitting, crimping, or welding.

[0039] In this embodiment, with the electrode body 600 housed in the container body 130, the container body 130 and the lid plates 110 and 120 are welded together to seal the inside of the container 100. The material of the container body 130 and the lid plates 110 and 120 is not particularly limited, but it is preferable that they be weldable metals such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet. The container 100 may also include other parts or components not shown, such as a gas discharge valve and a liquid filling section.

[0040] The electrode body 600 is an energy storage element (power generation element) that comprises a positive electrode plate, a negative electrode plate, and a separator, and is capable of storing electricity. The positive electrode plate is an electrode plate (electrode plate) in which a positive electrode active material layer is formed on the surface of a positive electrode current collector foil, which is a long, strip-shaped metal foil. The negative electrode plate is an electrode plate (electrode plate) in which a negative electrode active material layer is formed on the surface of a negative electrode current collector foil, which is a long, strip-shaped metal foil. Aluminum or an aluminum alloy is used for the positive electrode current collector foil. Copper or a copper alloy is used for the negative electrode current collector foil. As the positive electrode active material and the negative electrode active material, any known material that is capable of intercalating and releasing charge transport ions can be used as appropriate.

[0041] The electrode body 600 comprises an electrode body main body 601, a first connection portion 610 provided at the end of the electrode body main body 601 in the negative X-axis direction, and a second connection portion 620 provided at the end of the electrode body main body 601 in the positive X-axis direction. In this embodiment, the first connection portion 610 is a positive electrode tab portion in which a plurality of positive electrode tabs 611 are stacked, and the second connection portion 620 is a negative electrode tab portion in which a plurality of negative electrode tabs 621 are stacked.

[0042] More specifically, the electrode body 600 is a laminated electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator in between. In other words, the electrode body 600 comprises a plurality of positive electrode plates, each of which has a positive electrode tab 611 protruding in the negative X-axis direction. The positive electrode tab 611 is the portion of the positive electrode current collector foil in which the positive electrode active material layer is not formed. The plurality of positive electrode tabs 611 are stacked in the Y-axis direction to form a first connection portion 610. The electrode body 600 comprises a plurality of negative electrode plates, each of which has a negative electrode tab 621 protruding in the positive X-axis direction. The negative electrode tab 621 is the portion of the negative electrode current collector foil in which the negative electrode active material layer is not formed. The plurality of negative electrode tabs 621 are stacked in the Y-axis direction to form a second connection portion 620.

[0043] It is not essential that the electrode body 600 is a laminated electrode body. A wound electrode body formed by arranging a positive electrode plate and a negative electrode plate via a separator and winding them may be adopted as the electrode body 600. An electrode body in which a positive electrode plate and a negative electrode plate are arranged via a separator and are laminated in a bellows shape by repeating mountain folds and valley folds may be adopted as the electrode body 600.

[0044] As described above, the first connection portion 610 of the electrode body 600 is connected to the second terminal 250 via the current collector 550. Therefore, in the present embodiment, the second terminal 250 functions as the positive electrode terminal of the power storage element 10. The second connection portion 620 of the electrode body 600 is connected to the first terminal 200 via the current collector 500. Therefore, in the present embodiment, the first terminal 200 functions as the negative electrode terminal of the power storage element 10.

[0045] The bus bar 700 is a conductor that electrically connects two power storage elements 10 arranged in the X-axis direction. The bus bar 700 is formed of a conductive member such as aluminum, an aluminum alloy, copper, or a copper alloy. In the present embodiment, the bus bar 700 includes a first portion 710 connected to the first power storage element 10A, a second portion 720 connected to the second power storage element 10B, and an intermediate portion 750 connecting the first portion 710 and the second portion 720. That is, the first power storage element 10A and the second power storage element 10B are connected in series by the bus bar 700.

[0046] Hereinafter, the bus bar 700 and the surrounding configuration in the power storage device 1 of the present embodiment will be further described with reference to FIGS. 4 to 6.

[0047] [2. Configuration of the Busbar 700 and its Surroundings] Figure 4 is a schematic cross-sectional view showing the configuration of the busbar 700 and its surroundings in the energy storage device 1 according to the embodiment. In Figure 4, a part of the energy storage device 1, including the busbar 700 and its surroundings, is simply illustrated. The position of the cross-section in Figure 4 corresponds to the position of the cross-section in Figure 3. Figure 5 is a side view (viewed from the negative Y-axis direction) showing an example of the shape of the intermediate portion 750 of the busbar 700 according to the embodiment. Figure 6 is a simplified side view showing the configuration of the energy storage device 1 before the bending work on the busbar 700 is started. Figure 7 is a simplified side view showing the configuration of the energy storage device 1 after the bending work on the busbar 700 has started but before it is completed. The bending work on the busbar 700 is the work to form a bent portion 755 (see Figure 4), which is a folded portion from one direction to the opposite direction, in the intermediate portion 750 of the busbar 700.

[0048] In the following description, the first terminal 200, the second terminal 250, and the container 100 of the first energy storage element 10A will be referred to as the first terminal 200A, the second terminal 250A, and the first container 100A. The first terminal 200, the second terminal 250, and the container 100 of the second energy storage element 10B will be referred to as the first terminal 200B, the second terminal 250B, and the second container 100B.

[0049] As shown in Figures 2 to 4, in the energy storage device 1 according to this embodiment, the first energy storage element 10A comprises a first container 100A, a first terminal 200A located at the end of the first container 100A in the positive X-axis direction, and a second terminal 250A located at the end of the first container 100A in the negative X-axis direction. The second energy storage element 10B comprises a second container 100B, a first terminal 200B located at the end of the second container 100B in the positive X-axis direction, and a second terminal 250B located at the end of the second container 100B in the negative X-axis direction.

[0050] The first energy storage element 10A and the second energy storage element 10B are connected in series by a busbar 700. Specifically, the busbar 700 comprises a first part 710 connected to the first terminal 200A, which is the negative terminal of the first energy storage element 10A, and a second part 720 connected to the second terminal 250B, which is the positive terminal of the second energy storage element 10B. In other words, the first part 710 is fixed to the first terminal 200A in a state of electrical conductivity with the first terminal 200A, and the second part 720 is fixed to the second terminal 250B in a state of electrical conductivity with the second terminal 250B.

[0051] The busbar 700 further includes an intermediate portion 750 that connects the first portion 710 and the second portion 720. In this embodiment, the first portion 710 and the second portion 720 are plate-shaped portions with their thickness direction oriented in the X-axis direction, and the first portion 710 and the second portion 720 face each other in the X-axis direction. The intermediate portion 750 is a portion that connects (in other words, links) the Z-axis positive end of the first portion 710 and the Z-axis positive end of the second portion 720, and includes a convex bent portion 755 (see Figures 4 and 5) in the Z-axis positive direction.

[0052] The busbar 700 configured in this way may be formed by bending a long, flat metal plate approximately 180° around the central part in the longitudinal direction. In this embodiment, the intermediate portion 750 of the busbar 700 has a thin-walled portion 756 extending in the short direction of the busbar 700 (the Y-axis direction in Figures 4 and 5). The thin-walled portion 756 is a portion of the intermediate portion 750 that is thinner than the other parts. In this embodiment, the intermediate portion 750 is provided with a recess 758 extending in the Y-axis direction, which is recessed outward (in the Z-axis positive direction). In other words, the thin-walled portion 756 is formed by the outer (Z-axis positive direction) portion of the recess 758 in the intermediate portion 750. By providing the thin-walled portion 756 in the intermediate portion 750 of the busbar 700, a bent portion 755 can be formed based on the position of the thin-walled portion 756, and the ease of bending the busbar 700 (ease of forming the bent portion 755) is ensured.

[0053] When manufacturing the energy storage device 1 according to this embodiment, the busbar 700 is connected to the first terminal 200A and the second terminal 250B by welding or the like, and then the busbar 700 is bent. This results in the energy storage device 1 having the configuration shown in Figures 1 and 4.

[0054] Specifically, as shown in Figure 6, the first energy storage element 10A and the second energy storage element 10B are arranged in the Z-axis direction, the first part 710 of the busbar 700 is connected to the first terminal 200A of the first energy storage element 10A by welding or the like, and the second part 720 of the busbar 700 is connected to the second terminal 250B of the second energy storage element 10B by welding or the like.

[0055] In this embodiment, laser welding is used as the method for connecting the first part 710 to the first terminal 200A, and the method for connecting the second part 720 to the second terminal 250B. Specifically, with the first part 710 of the busbar 700 in contact with the first connection surface 202A, which is the end face of the first terminal 200A, laser light is irradiated onto the first part 710 from the positive X-axis direction. This allows the first part 710 and the first terminal 200A to be connected by through-welding. In other words, the welded portion 716 (see Figures 4 and 6) connecting the first part 710 and the first terminal 200A penetrates the first part 710 in the X-axis direction and extends to a position beyond the first connection surface 202A (negative X-axis direction in Figure 6). Connecting the first part 710 and the first terminal 200A by through-welding is not essential. However, connecting the first part 710 and the first terminal 200A by through welding is preferable, for example, from the viewpoint of improving the connection strength between the first part 710 and the first terminal 200A.

[0056] The same applies to the connection between the second part 720 and the second terminal 250B. That is, in Figure 6, with the second part 720 of the busbar 700 in contact with the second connection surface 252B, which is the end face of the second terminal 250B, laser light is shone onto the second part 720 from the positive X-axis direction. This allows the second part 720 and the second terminal 250B to be connected by through-welding. In other words, the welded portion 726 (see Figures 4 and 6) connecting the second part 720 and the second terminal 250B penetrates the second part 720 in the X-axis direction and extends to a position beyond the second connection surface 252B (negative X-axis direction in Figure 6). Connecting the second part 720 and the second terminal 250B by through-welding is not essential. However, connecting the second part 720 and the second terminal 250B by through-welding is preferable, for example, from the viewpoint of improving the connection strength between the second part 720 and the second terminal 250B.

[0057] The method of connecting the first part 710 to the first terminal 200A, and the method of connecting the second part 720 to the second terminal 250B, are not limited to laser welding. Other welding methods, or mechanical joining (screw connection, crimping, or press-fitting, etc.) may be used as these connection methods. There are no particular limitations on the order of connecting the first part 710 to the first terminal 200A, and the second part 720 to the second terminal 250B. The first part 710 to the first terminal 200A may be connected by welding or the like after connecting the second part 720 to the second terminal 250B. In Figures 6 and 7, the Z-axis direction does not need to coincide with the vertical direction. The XZ plane may coincide with the horizontal plane. That is, the welding and bending operations on the busbar 700 may be performed on the first energy storage element 10A and the second energy storage element 10B in a position where their respective long sides 101 are approximately parallel to the horizontal plane.

[0058] As described above, after the busbar 700 is connected to the first terminal 200A and the second terminal 250B by laser welding, the busbar 700 is bent. Specifically, one of the first energy storage element 10A and the second energy storage element 10B is moved to rotate around the middle section 750 of the busbar 700. As shown in Figures 6 and 7, the second energy storage element 10B is rotated clockwise around the middle section 750 of the busbar 700. At this time, since a thin section 756 is provided in the middle section 750 of the busbar 700, the busbar 700 is bent starting from the thin section 756. As a result, the busbar 700 goes through a shape where the angle between the first section 710 and the second section 720 is 90° (see Figure 7), and then to a shape where the first section 710 and the second section 720 are approximately parallel (see Figure 4). This completes the bending of the busbar 700. When performing the bending operation of the busbar 700 described above, jigs, tools, or machine tools, etc., not shown in Figures 6 and 7, may be used.

[0059] When the bending of the busbar 700 is completed, in the energy storage device 1, as shown in Figure 4, the first part 710 and the second part 720 face each other in the X-axis direction. The first terminal 200A and the second terminal 250B face each other in the X-axis direction. More specifically, the first connection surface 202A of the first terminal 200A and the second connection surface 252B of the second terminal 250B face each other in the X-axis direction.

[0060] The technical features of the energy storage device 1 according to the embodiment configured as described above are explained below.

[0061] The energy storage device 1 according to this embodiment comprises a first energy storage element 10A and a second energy storage element 10B, and a busbar 700 connecting the first energy storage element 10A and the second energy storage element 10B. The second energy storage element 10B is located on one side of the first energy storage element 10A in the first direction (the positive X-axis direction in this embodiment). The first energy storage element 10A has a first terminal 200A located in the positive X-axis direction, and the second energy storage element 10B has a second terminal 250B located in the negative X-axis direction. The busbar 700 comprises a first part 710 connected to the first terminal 200A, a second part 720 connected to the second terminal 250B, and an intermediate part 750 connecting the first part 710 and the second part 720. The intermediate part 750 has a bent portion 755 that is convex in the Z-axis direction intersecting the X-axis direction.

[0062] In the energy storage device 1 according to this embodiment, the first energy storage element 10A and the second energy storage element 10B are provided with terminals (first terminal 200A or second terminal 250B) in the direction in which these energy storage elements are aligned (X-axis direction). For example, when the first energy storage element 10A and the second energy storage element 10B are arranged horizontally, the height of the energy storage device 1 in the vertical direction can be made relatively low. Furthermore, the first terminal 200A and the second terminal 250B, which face each other, are connected by a busbar 700 having a convex bent portion 755 in a direction intersecting the X-axis direction. In other words, the busbar 700 can be connected to the first terminal 200A and the second terminal 250B by welding or the like. Therefore, the reliability of the connection between the first terminal 200A and the second terminal 250B is higher than when the first terminal 200A and the second terminal 250B are butted together and connected by welding or the like. Accordingly, the energy storage device 1 according to this embodiment is an energy storage device with improved reliability.

[0063] Specifically, consider the case where a first terminal 200A and a second terminal 250B, facing each other in the X-axis direction, are butted together and laser-welded. In this case, the laser beam is irradiated onto the boundary between the first terminal 200A and the second terminal 250B from a direction perpendicular to the X-axis direction. As a result, the weld is formed only on the periphery of the contact area between the first terminal 200A and the second terminal 250B. In other words, it is difficult to form a weld in the central part of the contact area between the first terminal 200A and the second terminal 250B when viewed in the X-axis direction. Therefore, it is difficult to ensure a sufficient welding area (in other words, the area of ​​the weld mark) and / or connection strength between the first terminal 200A and the second terminal 250B. In order to form a weld in the central part of the contact area, it is conceivable to increase the output of the laser beam, but in this case, other problems may arise, such as malfunctions due to increased heat generated during laser welding (for example, damage to the insulating member 220). Furthermore, when forming a welded area over a wide area around the periphery of the contact portion between the first terminal 200A and the second terminal 250B, it is necessary to irradiate the area with laser light from multiple directions perpendicular to the X-axis direction. This complicates the manufacturing process of the energy storage device 1 and / or increases the manufacturing cost of the energy storage device 1.

[0064] In the energy storage device 1 according to this embodiment, the first terminal 200A, which is the negative terminal of the first energy storage element 10A, and the second terminal 250B, which is the positive terminal of the second energy storage element 10B, are connected via a busbar 700. Furthermore, the intermediate portion 750 of the busbar 700 is provided with a bent portion 755 that is convex in a direction intersecting the X-axis direction. For example, the bent portion 755 can be formed in the intermediate portion 750 of the busbar 700 after the connection work between the busbar 700 and the first terminal 200A and the second terminal 250B has been performed. Therefore, the first part 710 of the busbar 700 and the first terminal 200A can be connected, for example, by through welding. The second part 720 of the busbar 700 and the second terminal 250B can be connected, for example, by through welding. In other words, the busbar 700 and each of the first terminal 200A and the second terminal 250B can be connected in a highly reliable manner. As a result, an energy storage device 1 with improved reliability can be obtained. By connecting the first part 710 and the first terminal 200A by through-welding, a relatively large welding area can be secured in the center of the first connection surface 202A (see Figures 4 and 6) when viewed from the X-axis direction. This improves the connection strength between the first part 710 and the first terminal 200A. Similarly, by connecting the second part 720 and the second terminal 250B by through-welding, a relatively large welding area can be secured in the center of the second connection surface 252B (see Figures 4 and 6) when viewed from the X-axis direction. This improves the connection strength between the second part 720 and the second terminal 250B.

[0065] In this embodiment, as shown in Figure 4, the first part 710 and the second part 720 are arranged between the first terminal 200A and the second terminal 250B.

[0066] In this configuration, the first part 710 and the second part 720 of the busbar 700 are positioned between two terminals (first terminal 200A and second terminal 250B) and connected by an intermediate part 750 having a convex bent portion 755 in the Z-axis direction. For example, the busbar 700 can be realized by a conductor including a simple U-shaped portion.

[0067] In this embodiment, the bent portion 755 includes a thin-walled portion 756 that extends in the Y-axis direction.

[0068] In other words, before bending, the busbar 700 has a thin-walled portion 756 extending in the short direction of the busbar 700. Therefore, the bent portion 755 can be formed accurately and / or efficiently using the position of the thin-walled portion 756 of the busbar 700 as a reference.

[0069] In the energy storage device 1 according to this embodiment, the intermediate portion 750 of the busbar 700 can also be used as a portion where a wiring member 790 for voltage detection or temperature detection is arranged, as shown in Figure 5. In other words, the energy storage device 1 may further include a wiring member 790 arranged in the intermediate portion 750. The wiring member 790 includes a detection terminal 791 which is a metal terminal or thermistor, and an electric wire 792 connected to the detection terminal 791.

[0070] With this configuration, the intermediate portion 750, which is not directly connected to the first terminal 200A and the second terminal 250B, can be effectively utilized as a portion for arranging the wiring member 790. More specifically, as shown in Figure 5, at least a portion of the detection terminal 791 may be placed in the busbar space 759, which is the space inside the bent portion 755 in the intermediate portion 750 (in the negative Z-axis direction). That is, the intermediate portion 750 according to this embodiment is provided with a bent portion 755 that is convex in a direction intersecting the X-axis direction (in this embodiment, the positive Z-axis direction). Therefore, a busbar space 759 may be formed inside the bent portion 755. By housing the detection terminal 791 in this busbar space 759, the busbar space 759 can be effectively utilized.

[0071] There are no particular limitations on the placement of the detection terminal 791 in the intermediate section 750. The detection terminal 791 may be placed on the outer surface of the intermediate section 750. Mounting materials such as adhesive tape, screws, or adhesives may be used to attach the detection terminal 791 to the intermediate section 750. The wire 792 provided by the wiring member 790 may be placed in the intermediate section 750. A portion of the wire 792 may be inserted into the busbar internal space 759, or the wire 792 may pass through the busbar internal space 759.

[0072] In this embodiment, as shown in Figure 4, the first terminal 200A has a first connection surface 202A to which the first part 710 is connected, and the second terminal 250B has a second connection surface 252B to which the second part 720 is connected. The first connection surface 202A and the second connection surface 252B face each other in the X-axis direction.

[0073] Thus, the first connection surface 202A and the second connection surface 252B face each other in the direction of alignment of the first energy storage element 10A and the second energy storage element 10B. Therefore, the busbar 700, which includes an intermediate portion 750 with a bent portion 755, can be obtained, for example, by bending a plate-shaped member in the thickness direction. In other words, the busbar 700 can be realized by a conductor with a simple U-shaped overall form.

[0074] [3. Modified Forms] Figure 8 is a schematic cross-sectional view showing the configuration of the busbar 700a and its surroundings in a modified form of the embodiment of the energy storage device 1a. In Figure 8, a part of the energy storage device 1a, including the busbar 700a and its surroundings, is simply illustrated. The position of the cross-section in Figure 8 corresponds to the position of the cross-section in Figure 3.

[0075] The modified energy storage device 1a comprises a first energy storage element 10A and a second energy storage element 10B arranged in the X-axis direction, and a busbar 700a connecting the first energy storage element 10A and the second energy storage element 10B. The busbar 700a comprises a first part 710 connected to the first terminal 200A of the first energy storage element 10A, a second part 720 connected to the second terminal 250B of the second energy storage element 10B, and an intermediate part 750 connecting the first part 710 and the second part 720. The intermediate part 750 has a bent portion 755 that is convex in the Z-axis direction intersecting the X-axis direction. These configurations are common to the energy storage device 1 according to the embodiment.

[0076] In the modified energy storage device 1a, the first part 710 and the second part 720 of the busbar 700a are in contact with each other in the X-axis direction, and in this respect, it differs from the energy storage device 1 according to the embodiment.

[0077] Thus, in this modified example, since the first part 710 and the second part 720 of the busbar 700a are in contact in the X-axis direction, the formation of a gap between the first part 710 and the second part 720 is suppressed. This suppresses the increase in the size of the energy storage device 1a in the X-axis direction caused by connecting the first energy storage element 10A and the second energy storage element 10B with the busbar 700a. Because the first part 710 and the second part 720 are in contact in the X-axis direction, the first part 710 and the second part 720 conduct electricity without going through the intermediate part 750. Therefore, the increase in electrical resistance in the conduction path between the first energy storage element 10A and the second energy storage element 10B can be suppressed.

[0078] The state in which the first part 710 and the second part 720 of the busbar 700a are in contact in the X-axis direction and the maintenance thereof may be achieved by compressing the first energy storage element 10A and the second energy storage element 10B in the X-axis direction using a restraining member or the like. The state in which the first part 710 and the second part 720 are in contact in the X-axis direction may be maintained by plastic deformation of the busbar 700a.

[0079] [4. Other Modifications] Although embodiments of the present invention and modified versions thereof have been described above, the present invention is not limited to these embodiments and modifications. In other words, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is intended to include all modifications in the sense and scope equivalent to the claims.

[0080] In the electrode body 600, the first connection portion 610 may be the negative electrode and the second connection portion 620 may be the positive electrode. In other words, the second terminal 250 electrically connected to the first connection portion 610 may be the negative electrode terminal of the energy storage element 10, and the first terminal 200 electrically connected to the second connection portion 620 may be the positive electrode terminal of the energy storage element 10.

[0081] The energy storage element 10 does not necessarily have a current collector 500. The second connection part 620 may be directly connected to a part of the first terminal 200, such as a crimped part 211 (see Figure 3), by welding or the like. In other words, the first terminal 200 may have a part that functions as a current collector 500. Similarly, the energy storage element 10 does not necessarily have a current collector 550, and the second terminal 250 may have a part that functions as a current collector 550.

[0082] The current collector 500 may include a current collector shaft portion, which corresponds to the shaft portion 210 of the first terminal 200. In this case, the first terminal 200 may consist only of a terminal body 201 having a through hole through which the current collector shaft portion passes. That is, the current collector shaft portion may have a crimping portion 211 at the tip that is exposed to the outside while passing through the through hole of the terminal body 201. Even with such a configuration, the second connection portion 620 of the electrode body 600 and the first terminal 200 are electrically connected, and the first terminal 200 is fixed to the cover plate 110. Similarly, the current collector 550 may include a current collector shaft portion, which corresponds to the shaft portion 260 of the second terminal 250. In this case, the second terminal 250 may consist only of a terminal body 251 having a through hole through which the current collector shaft portion passes. That is, the current collector shaft portion may have a crimping portion 261 at the tip that is exposed to the outside while passing through the through hole of the terminal body 251. Even with this configuration, the first connection portion 610 of the electrode body 600 and the second terminal 250 are electrically connected, and the second terminal 250 is fixed to the cover plate 120.

[0083] The busbar 700 may have through holes, recesses, or notches. If the crimped portion 211 protrudes outward from the first connection surface 202A of the first terminal 200A, the first part 710 of the busbar 700 may have through holes, recesses, or notches at a position opposite to the crimped portion 211 in the X-axis direction. This allows the first part 710 to be connected to the first connection surface 202A by welding or the like while avoiding interference between the first part 710 and the crimped portion 211. If the crimped portion 261 protrudes outward from the second connection surface 252B of the second terminal 250B, the second part 720 of the busbar 700 may have through holes, recesses, or notches at a position opposite to the crimped portion 261 in the X-axis direction. This allows the second part 720 to be connected to the second connection surface 252B by welding or the like while avoiding interference between the second part 720 and the crimped portion 261.

[0084] In Figure 4, the intermediate portion 750 of the busbar 700 protrudes in the positive Z-axis direction beyond the Z-axis positive edges of the first energy storage element 10A and the second energy storage element 10B, but this is not essential. In the Z-axis direction, the position of the Z-axis positive edge of the intermediate portion 750 of the busbar 700 may be the same as the position of the Z-axis positive edges of the first energy storage element 10A and the second energy storage element 10B. The position of the Z-axis positive edge of the intermediate portion 750 of the busbar 700 may be in the negative Z-axis direction beyond the Z-axis positive edges of the first energy storage element 10A and the second energy storage element 10B. In other words, when the energy storage device 1 is viewed from the X-axis direction, the entire area of ​​the busbar 700 in the Z-axis direction may overlap with the first energy storage element 10A or the second energy storage element 10B. In this way, by not including a portion (part of the busbar 700) that protrudes in the positive Z-axis direction from the first energy storage element 10A and the second energy storage element 10B, the energy storage device 1 can be miniaturized in the Z-axis direction.

[0085] The first connection portion 610 and the second connection portion 620 do not need to be tab portions formed by stacking tabs of electrode plates. If a wound electrode body is used as the electrode body 600, the first connection portion 610 may be located at one end in the direction of the winding axis and may be formed by a wound positive electrode current collector foil. Similarly, the second connection portion 620 may be located at the other end in the direction of the winding axis and may be formed by a wound negative electrode current collector foil.

[0086] The shape of the busbar 700 does not need to be U-shaped as shown in Figures 2 and 4. The busbar 700 only needs to have a first part 710 connected to the first terminal 200A of the first energy storage element 10A, and a second part 720 connected to the second terminal 250B of the second energy storage element 10B, and there are no particular limitations on the overall shape of the busbar 700. The bent portion 755 of the intermediate portion 750 does not need to be curved as shown in Figure 5, and may be a bent shape that is convex in the Z-axis positive direction. The intermediate portion 750 may have an end face formed between the two bent portions (corners) that is parallel to the XY plane and faces in the Z-axis positive direction. In this case, the detection terminal 791 of the wiring member 790 may be placed on the end face.

[0087] The recess 758 (see Figure 5) in the intermediate portion 750 of the busbar 700 may be formed on the outer surface of the intermediate portion 750. In other words, the recess 758 may be positioned in a way that it opens in the positive Z-axis direction in the busbar 700 (see Figure 5) after the bending work is completed. In this case, the inner portion (negative Z-axis direction) of the recess 758 forms the thin-walled portion 756.

[0088] The direction in which the bent portion 755 protrudes in the intermediate portion 750 of the busbar 700 does not need to be in the positive Z-axis direction. The intermediate portion 750 only needs to have a bent portion 755 that is convex in a direction intersecting the alignment direction of the first energy storage element 10A and the second energy storage element 10B (the X-axis direction in this embodiment). Therefore, if the intermediate portion 750 is arranged in the positive Y-axis direction of the first portion 710 and the second portion 720, the intermediate portion 750 may have a bent portion 755 that is convex in the positive Y-axis direction. Similarly, the intermediate portion 750 may have a bent portion 755 that is convex in the negative Y-axis direction or the negative Z-axis direction.

[0089] Part of the bending work on the busbar 700 may be performed after the connection work (laser welding, etc.) between the busbar 700 and the first terminal 200A and the second terminal 250B. As shown in Figure 7, the connection work between the busbar 700 and the first terminal 200A and the second terminal 250B may be performed after the busbar 700 has been bent by approximately 90°. In this case, by further bending the busbar 700 after the connection work between the busbar 700 and the first terminal 200A and the second terminal 250B, a busbar 700 with the shape shown in Figure 4 can be obtained.

[0090] The positional relationship between the first energy storage element 10A and the second energy storage element 10B at the time of connecting the busbar 700 to the first terminal 200A and the second terminal 250B is not limited to the positional relationship shown in Figure 6, and various positional relationships are possible. The connection work between the first terminal 200A and the busbar 700, and the connection work between the second terminal 250B and the busbar 700 may be performed with the first energy storage element 10A and the second energy storage element 10 facing each other in the X-axis direction.

[0091] The container 100 for the energy storage element 10 does not necessarily have to be a rectangular container. A container whose shape when viewed from the X-axis direction is circular, oval, elliptical, or a polygon other than a rectangle may be used as the container 100 for the energy storage element 10. In any case, the energy storage element 10 may be provided with terminals (first terminal 200 and second terminal 250) located at both ends of the container 100 in the X-axis direction. The busbar 700 may include a first part 710 connected to the first terminal 200A of the first energy storage element 10A, a second part 720 connected to the second terminal 250 of the second energy storage element 10B, and an intermediate part 750 connecting the first part 710 and the second part 720.

[0092] The first terminal 200A of the first energy storage element 10A and the second terminal 250B of the second energy storage element 10B do not have to face each other in the X-axis direction. When viewed from the direction of alignment of the first energy storage element 10A and the second energy storage element 10B (in the X-axis direction), the first terminal 200A and the second terminal 250B may be positioned so as not to overlap. In other words, the first connection surface 202A of the first terminal 200A and the second connection surface 252B of the second terminal 250B do not have to face each other in the X-axis direction. In this case, the first part 710 and the second part 720 of the busbar 700 do not have to face each other in the X-axis direction. In short, the energy storage device 1 does not have to have a configuration in which the first part 710 and the second part 720 are arranged between the first terminal 200A and the second terminal 250B. In this case, the busbar 700 has a first part 710 positioned opposite the first terminal 200A and a second part 720 positioned opposite the second terminal 250B, making it possible to connect the first part 710 to the first terminal 200A by welding or the like, and the second part 720 to the second terminal 250B by welding or the like.

[0093] The bent portion 755 of the busbar 700 does not necessarily have to include a thin-walled portion 756. Even if the thickness of the base material forming the busbar 700 is relatively small, or if there is no thin-walled portion 756 in the part of the base material corresponding to the bent portion 755, it is still possible to form the bent portion 755.

[0094] The first part 710 does not have to be a plate-shaped portion of the busbar 700 with its thickness direction oriented in the X-axis direction. If the first terminal 200A has a relatively large end face (first connection surface) on a side facing the Y-axis direction, the first part 710 may be a plate-shaped portion with its thickness direction oriented in the Y-axis direction. This makes the connection area between the first part 710 and the first terminal 200A relatively large. The first part 710 may also be a rod-shaped portion extending in the Z-axis direction. The first part 710 only needs to be connectable to the first terminal 200A by a predetermined connection method such as welding, and the external shape of the first part 710 is not limited to a specific shape. The same applies to the second part 720 of the busbar 700, and the external shape of the second part 720 is not limited to a specific shape.

[0095] An insulating member may be placed between the busbar 700 and the energy storage element 10 connected to the busbar 700. In Figure 4, an insulating member (not shown) may be placed between the busbar 700 and the cover plate 110 of the first energy storage element 10A, and / or between the busbar 700 and the cover plate 120 of the second energy storage element 10B. This suppresses electrical contact between adjacent busbars 700 and the container 100 of the energy storage element 10 in the X-axis direction due to vibration or shock.

[0096] The energy storage device 1 may be implemented as an energy storage device 1 comprising three or more energy storage elements 10 as described above. If another energy storage element 10 is arranged in the positive X-axis direction of the second energy storage element 10B, a new busbar 700 may be provided to connect the first terminal 200B of the second energy storage element 10B to the second terminal 250 of the other energy storage element 10. If another energy storage element 10 is arranged in the negative X-axis direction of the first energy storage element 10A, a new busbar 700 may be provided to connect the first terminal 200 of the other energy storage element 10 to the second terminal 250A of the first energy storage element 10A.

[0097] When the energy storage device 1 includes three or more energy storage elements 10, it is not necessary for all of the energy storage elements 10 to be connected in the manner shown in Figures 1, 2, and 4. The energy storage device 1 may have only one pair of energy storage elements 10 (i.e., the first energy storage element 10A and the second energy storage element 10B) connected in the manner shown in Figures 1, 2, and 4. In other words, the energy storage device 1 only needs to include at least two energy storage elements 10, which are the first energy storage element 10A and the second energy storage element 10B, and one busbar 700 connecting the two energy storage elements 10.

[0098] If a plurality of energy storage elements 10 are arranged in the X-axis direction, and two adjacent energy storage elements 10 are connected by a busbar 700, and these plurality of energy storage elements 10 constitute one row of energy storage elements 10, then the energy storage device 1 may also include a plurality of rows of energy storage elements 10 arranged in the Y-axis direction. In this case, two adjacent rows of energy storage elements 10 in the Y-axis direction may be connected in series or in parallel. That is, the energy storage device 1 may be realized as an energy storage device 1 comprising a plurality of energy storage elements 10 arranged in a matrix on the XY plane. An energy storage device 1 comprising one or more rows of energy storage elements 10 may be used as at least one energy storage module in a battery pack comprising a plurality of energy storage modules.

[0099] The present invention also includes forms constructed by arbitrarily combining the components included in the above embodiments and their modified examples.

[0100] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries.

[0101] 1, 1a Energy storage device 10 Energy storage element 10A First energy storage element 10B Second energy storage element 200, 200A, 200B First terminal 202A First connection surface 250, 250A, 250B Second terminal 252B Second connection surface 700, 700a Busbar 710 First part 716, 726 Welded part 720 Second part 750 Intermediate part 755 Bent part 756 Thin-walled part 758 Recess 790 Wiring member

Claims

1. An energy storage device comprising: a first energy storage element and a second energy storage element; a busbar connecting the first energy storage element and the second energy storage element, wherein the second energy storage element is located on one side of the first energy storage element in a first direction; the first energy storage element has a first terminal located on the one side of the first direction; the second energy storage element has a second terminal located on the other side of the first direction; the busbar comprises: a first part connected to the first terminal; a second part connected to the second terminal; and an intermediate part connecting the first part and the second part; wherein the intermediate part has a bent portion that protrudes in a second direction intersecting the first direction.

2. The energy storage device according to claim 1, wherein the first part and the second part are arranged between the first terminal and the second terminal.

3. The energy storage device according to claim 2, wherein the first part and the second part are in contact with each other in the first direction.

4. The energy storage device according to any one of claims 1 to 3, wherein the bent portion comprises a thin-walled portion extending in a third direction intersecting the first direction and the second direction.

5. The energy storage device according to any one of claims 1 to 3, further comprising a wiring member arranged in the intermediate portion.

6. The energy storage device according to any one of claims 1 to 3, wherein the first terminal has a first connection surface to which the first part is connected, the second terminal has a second connection surface to which the second part is connected, and the first connection surface and the second connection surface face each other in the first direction.

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