Power storage device

Abstract

This power storage device comprises a power storage element comprising a terminal to which a bus bar is connected, wherein: the terminal is provided with a facing surface which faces the bus bar and which is in contact with the bus bar; the facing surface is provided with a mark part on which marking has been performed; and the mark part is a recessed part of the facing surface recessed in the alignment direction of the bus bar and the terminal, and is disposed at a position not overlapping the bus bar when viewed from the alignment direction.

Description

Power storage device

[0001] The present invention relates to an electricity storage device.

[0002] Patent Document 1 discloses a power supply device in which, of the cathode and anode terminals provided on a sealing terminal plate of an electronic component, a circular hole is formed only in the annular upper end surface of the cathode terminal, while a bus bar connected to the cathode terminal is formed with a protrusion that fits into the circular hole, thereby preventing reverse polarity connection.

[0003] JP 2008-10493 A

[0004] In the conventional power supply device described above, the protrusion of the bus bar is inserted into the circular hole of the cathode terminal to prevent reverse polarity connection. However, with this configuration, it can be difficult to determine the position of the protrusion of the bus bar relative to the circular hole of the cathode terminal when connecting the bus bar to the cathode terminal, which can make it difficult to connect the bus bar to the cathode terminal.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide an electricity storage device in which bus bars can be easily connected to terminals of electricity storage elements.

[0006] An energy storage device according to one aspect of the present invention includes an energy storage element having a terminal to which a bus bar is connected, the terminal having an opposing surface that faces the bus bar and is in contact with the bus bar, the opposing surface having a mark portion on which a mark is applied, the mark portion being a recess in the opposing surface that is recessed in the direction of alignment of the bus bar and the terminal, and is positioned at a position that does not overlap with the bus bar when viewed from the direction of alignment.

[0007] According to the electricity storage device of the present invention, the bus bars can be easily connected to the terminals of the electricity storage elements.

[0008] FIG. 1 is a perspective view showing the configuration of an energy storage device according to an embodiment. FIG. 2 is a perspective view showing the configuration of an energy storage element according to an embodiment. FIG. 3 is a plan view showing the configuration of a terminal of an energy storage element according to an embodiment. FIG. 4 is a cross-sectional view showing the configuration of a terminal of an energy storage element according to an embodiment. FIG. 5 is a perspective view showing the configuration of a terminal and a bus bar of an energy storage element according to an embodiment. FIG. 6 is a plan view showing the configuration of a terminal and a bus bar of an energy storage element according to an embodiment. FIG. 7 is a cross-sectional view showing the configuration of a terminal and a bus bar of an energy storage element according to an embodiment. FIG. 8 is a plan view showing the configuration of a terminal of an energy storage element according to a first modified example of the embodiment. FIG. 9 is a cross-sectional view showing the configuration of a terminal and a bus bar of an energy storage element according to a second modified example of the embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention includes an energy storage element having a terminal to which a bus bar is connected, the terminal having an opposing surface facing the bus bar and in contact with the bus bar, the opposing surface having a mark portion on which a mark is applied, the mark portion being a recess in the opposing surface that is recessed in the direction of alignment of the bus bar and the terminal, and is positioned so as not to overlap the bus bar when viewed from the direction of alignment.

[0010] In an energy storage device according to one aspect of the present invention, the terminals of the energy storage elements include mark portions on the surfaces facing the busbars. The mark portions are recessed in the direction of alignment of the busbars and the terminals, and are positioned so as not to overlap the busbars when viewed from the direction of alignment. Because the terminals of the energy storage elements include the mark portions, when connecting the busbars to the terminals of the energy storage elements, the mark portions can be used as a guide to easily position the busbars relative to the terminals. Because the mark portions are recessed, contact between the mark portions and the busbars can be prevented when connecting the busbars to the terminals. Because the mark portions do not overlap the busbars when viewed from the direction of alignment, the position of the mark portions can be ascertained from the direction of alignment when connecting the busbars to the terminals. These features make it easy to connect the busbars to the terminals of the energy storage elements.

[0011] (2) In the energy storage device described above in (1), the bus bars may have openings, and the marking portions may be disposed within the openings when viewed from the arrangement direction.

[0012] According to the energy storage device described in (2) above, the markings are disposed within the openings of the bus bars when viewed from the arrangement direction, which allows the positions of the markings to be ascertained from the openings of the bus bars when connecting the bus bars to the terminals of the energy storage elements.

[0013] (3) In the energy storage device described in (1) or (2) above, the marking portion may be a recessed portion having a color different from that of a portion of the opposing surface that is different from the marking portion.

[0014] According to the energy storage device described above in (3), the marking portion is a recessed portion having a different color from the other portions of the opposing surface. By making the color of the marking portion different in this way, the position of the marking portion can be easily identified when connecting the bus bar to the terminal of the energy storage element.

[0015] (4) In the energy storage device described in any one of (1) to (3) above, the energy storage element may have a positive terminal and a negative terminal as the terminals, and both the positive terminal and the negative terminal may have the mark portion.

[0016] According to the energy storage device described in (4) above, both the positive and negative terminals of the energy storage elements are provided with the marking portions, thereby making it possible to easily connect the bus bars to both the positive and negative terminals using the marking portions.

[0017] (5) In the energy storage device according to any one of (1) to (4) above, the bus bar may cover an outer edge of the terminal when viewed from the arrangement direction.

[0018] According to the energy storage device described in (5) above, the bus bar covers the outer edges of the terminals, making it difficult to grasp the positions of the outer edges of the terminals. However, even in this case, the markings can be used to easily position the bus bar relative to the terminals.

[0019] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including modifications thereof). The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are designated by the same reference numerals.

[0020] In the following description and drawings, the longitudinal direction of the energy storage element, the arrangement direction of a pair of terminals (positive and negative electrodes) of the energy storage element, or the opposing direction of a pair of short side surfaces of the container for the energy storage element is defined as the X-axis direction. The arrangement direction of multiple energy storage elements, the thickness direction (flattening direction) of the energy storage element, or the opposing direction of a pair of long side surfaces of the container for the energy storage element is defined as the Y-axis direction. The arrangement direction of the energy storage element or its terminals and the bus bar, the protruding direction of the terminals of the energy storage element, the arrangement direction of the container body and the lid of the container for the energy storage element, or the up-down direction is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Depending on the usage mode, the Z-axis may not be the up-down direction; however, for convenience of explanation, the following description will be made assuming that the Z-axis direction is the up-down direction.

[0021] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. Simply referring to the X-axis direction refers to both or either of the positive and negative X-axis directions. References to one side and the other side of the X-axis direction refer to one and the other of the positive and negative X-axis directions. Unless otherwise specified, the center and end portions of a component in the X-axis direction refer to the central and end portions when the component is divided into thirds along the X-axis. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or orientations, such as "parallel" and "orthogonal," may also refer to cases where the directions or orientations are not strictly the same. Two directions being parallel (or orthogonal) not only means that the two directions are completely parallel (or orthogonal), but also means that the two directions are substantially parallel (or orthogonal), i.e., there is a difference of, for example, a few percent. In the following description, the term "insulating" refers to "electrical insulating." The volume resistivity of an insulating material is 1×10 ６ Ωm or more is preferable, and 1×10 ７ Ωm or more is more preferable, and 1×10 １０ More preferably, it is Ωm or more.

[0022] (Embodiment) [1 General Description of Energy Storage Device 10] First, a general description of the energy storage device 10 in this embodiment will be given. Fig. 1 is a perspective view showing the configuration of the energy storage device 10 according to this embodiment. Fig. 1 shows the general outline of an exterior body 300 provided in the energy storage device 10 with a dashed line (two-dot chain line), and is a view showing the inside of the exterior body 300 by looking through the exterior body 300.

[0023] The power storage device 10 is a device capable of charging with electricity from an external source and discharging electricity to an external source. In this embodiment, the power storage device 10 has a substantially rectangular parallelepiped shape. A rectangular parallelepiped is a hexahedron with all faces formed of rectangles or squares. The same applies below. The power storage device 10 is a battery module (battery assembly) used for power storage, power supply, etc. The power storage device 10 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, automatic guided vehicle (AGV), or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 10 can also be used as a stationary battery for home or business use.

[0024] 1, the energy storage device 10 includes a plurality of energy storage elements 100, a plurality of bus bars 200, and an exterior body 300. The energy storage device 10 also includes spacers or holders arranged adjacent to the energy storage elements 100, but these are not shown or described here. This also applies to the subsequent figures. The spacers or holders are formed of a resin member or the like that has the function of insulating and / or heat-insulating the energy storage elements 100 from other members (other energy storage elements 100 or the exterior body 300). In addition to the above components, the energy storage device 10 may also include a bus bar frame for positioning the bus bar 200, external terminals for connecting to external conductive members, bus bars for connecting the external terminals to the energy storage elements 100, an exhaust section for exhausting gas discharged from the energy storage elements 100, restraining members (end plates, side plates, etc.) for restraining the multiple energy storage elements 100, and electrical equipment such as circuit boards, fuses, relays, and connectors for monitoring or controlling the charge and discharge states of the energy storage elements 100.

[0025] The energy storage element 100 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 100 has a rectangular parallelepiped shape (square or rectangular) that is long in the X-axis direction and flat in the Y-axis direction. In this embodiment, multiple (eight) energy storage elements 100 are arranged side by side in the Y-axis direction, but the number of arranged energy storage elements 100 is not particularly limited and may be just one. The size and shape of the energy storage element 100 are also not particularly limited. They do not need to be long in the X-axis direction or flat in the Y-axis direction. They may also be oval, elliptical, cylindrical, or polygonal prism shapes other than rectangular parallelepipeds. The energy storage element 100 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 100 may be a primary battery instead of a secondary battery. The energy storage element 100 may be a battery using a solid electrolyte. The energy storage element 100 may be a pouch-type energy storage element. The configuration of the energy storage element 100 will be described in detail later.

[0026] The bus bar 200 is a plate-like, rectangular member disposed on the plurality of energy storage elements 100 and electrically connects the terminals 140 (see FIG. 2 , etc.) of the plurality of energy storage elements 100 to one another. The bus bar 200 is disposed alongside the energy storage elements 100 in a direction (Z-axis direction) intersecting the arrangement direction (Y-axis direction) of the energy storage elements 100. In the present embodiment, the bus bar 200 is joined to the terminals 140 of the energy storage elements 100 by welding. The bus bar 200 is formed of a conductive member made of a metal such as aluminum, an aluminum alloy, copper, a copper alloy, or nickel, or a combination thereof, or a conductive member other than a metal. In the present embodiment, the bus bar 200 connects the terminals 140 of the eight energy storage elements 100 in series by connecting the terminals 140 of opposite polarities to one another. The bus bar 200 may connect some of the energy storage elements 100 in parallel and then connect them in series, or it may connect all of the energy storage elements 100 in parallel. A detailed description of the configuration of the bus bar 200 will be given later.

[0027] The exterior body 300 is a component disposed outside the plurality of energy storage elements 100, the plurality of bus bars 200, and the like. In the present embodiment, the exterior body 300 is a substantially rectangular parallelepiped (box-shaped) container (module case) that houses the plurality of energy storage elements 100, the plurality of bus bars 200, and the like. That is, the exterior body 300 is disposed outside the plurality of energy storage elements 100, the plurality of bus bars 200, and the like, and fixes the plurality of energy storage elements 100, etc. at predetermined positions to protect them from impacts and the like. The exterior body 300 is formed of an insulating component, such as any resin material that can be used for the gasket 170 provided in the energy storage element 100, which will be described later, and prevents the energy storage elements 100, etc. from coming into contact with external metal components and the like. As long as the insulation properties of the energy storage elements 100, etc. are maintained, the exterior body 300 may be formed of a metal component, such as aluminum, an aluminum alloy, stainless steel, iron, or a plated steel sheet.

[0028] [2 Description of Energy Storage Element 100] Next, the configuration of the energy storage element 100 will be described in detail. Fig. 2 is a perspective view showing the configuration of the energy storage element 100 according to this embodiment. Fig. 2 is an enlarged view of the energy storage element 100 shown in Fig. 1, and the internal configuration of the container 110 is indicated by a dashed line. Since the multiple energy storage elements 100 included in the energy storage device 10 all have the same configuration, Fig. 2 shows one energy storage element 100, and the configuration of one energy storage element 100 will be described in detail below.

[0029] As shown in FIG. 2 , the energy storage element 100 includes a container 110, a pair of (positive and negative) terminals 140, an electrode assembly 150, a pair of (positive and negative) current collectors 160, and a pair of (positive and negative) gaskets 170. The electrode assembly 150 and the current collectors 160 are shown by dashed lines because they are disposed inside the container 110. An electrolyte (non-aqueous electrolyte) is also enclosed inside the container 110, but is not shown. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage element 100, and various types can be selected. In addition to the above components, the energy storage element 100 may also include spacers disposed on the sides or below the electrode assembly 150, an insulating film encasing the electrode assembly 150, and an insulating film (such as a shrink tube) covering the outer surface of the container 110.

[0030] The container 110 is a rectangular parallelepiped (square or box-shaped) case including a container body 120 with an opening facing the positive direction of the Z axis and a lid 130 that closes the opening of the container body 120. After the electrode assembly 150 and other components are housed inside the container body 120, the container body 120 and the lid 130 are joined by welding or the like, thereby sealing the interior of the container 110. The material of the container 110 (container body 120 and lid 130) is not particularly limited and may be a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, or a resin. The container body 120 and the lid 130 may be formed of the same material or different materials.

[0031] The container body 120 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 110. The container body 120 has a pair of long side walls 111 on both sides in the Y-axis direction (long sides), a pair of short side walls 112 on both sides in the X-axis direction (short sides), and a bottom wall 113 on the surface in the negative Z-axis direction (bottom). The long side walls 111 are flat, rectangular walls extending in the X-axis direction, the short side walls 112 are flat, rectangular walls extending in the Z-axis direction, and the bottom wall 113 is a flat, rectangular wall extending in the X-axis direction. The lid 130 is a flat, rectangular member that constitutes the lid of the container 110 and is arranged in the positive Z-axis direction of the container body 120. The lid 130 is provided with a gas exhaust valve 131 for releasing the pressure inside the container 110 if the pressure inside the container 110 rises excessively, and a liquid injection section (not shown) for injecting the electrolyte into the container 110.

[0032] The terminals 140 are electrode terminals (positive and negative terminals) electrically connected to the electrode body 150 via the current collector 160. A pair of terminals 140 (positive and negative terminals) aligned in the X-axis direction are disposed protruding in the positive Z-axis direction from the outer surface (the surface facing the positive Z-axis direction) of the lid body 130. The terminals 140 are metal members for conducting electricity stored in the electrode body 150 to the external space of the energy storage element 100 and for introducing electricity into the internal space of the energy storage element 100 to store electricity in the electrode body 150. The terminals 140 are formed of a conductive material such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. The terminals 140 are connected (joined) to the current collector 160 by crimping or the like, and are attached to the lid body 130 (see FIG. 4 , etc.). The method of connecting (joining) the terminal 140 and the current collector 160 is not limited to crimping, and may be ultrasonic welding, laser welding, resistance welding, or other welding, or mechanical joining other than crimping, such as screw joining.

[0033] As described above, the bus bar 200 is connected to the terminal 140. In the present embodiment, the terminal 140 is a welded terminal that is joined to the bus bar 200 by welding. The terminal 140 has a facing surface 140a that faces the bus bar 200 and comes into contact with the bus bar 200, and the facing surface 140a has a marking portion 140c. As described above, the energy storage element 100 has a positive electrode terminal and a negative electrode terminal as the terminals 140, and both of these positive electrode terminals and negative electrode terminals have a marking portion 140c. In other words, both the positive electrode terminal and the negative electrode terminal have a facing surface 140a that faces the bus bar 200 and comes into contact with the bus bar 200, and in both the positive electrode terminal and the negative electrode terminal, the facing surface 140a has a marking portion 140c. A more detailed description of the configuration of the terminal 140 will be given later.

[0034] The electrode assembly 150 is a storage element (power generating element) capable of storing electricity, and includes a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on a current collector foil made of a metal such as copper or a copper alloy. The separator is a microporous sheet made of resin. Any known material can be used as the positive electrode active material used in the positive electrode active material layer and the negative electrode active material used in the negative electrode active material layer, as long as it is capable of absorbing and releasing charge transport ions. Any known material can also be used for the separator, as long as it does not impair the performance of the energy storage element 100.

[0035] In this embodiment, the electrode assembly 150 is a wound-type electrode assembly formed by winding layers of positive and negative electrode plates sandwiched between them with a separator around a winding axis parallel to the X-axis direction. In the electrode assembly 150, the positive and negative electrode plates are wound with the separator interposed between them and offset from each other in the direction of the winding axis (X-axis direction). The positive and negative electrode plates have portions at their offset ends where no active material is formed (coated) and the current collecting foil is exposed, and these ends are electrically and mechanically connected to the current collector 160. The electrode assembly 150 may also be a wound-type electrode assembly formed by winding the positive and negative electrode plates and the separator around a winding axis parallel to the Z-axis direction. The electrode body 150 may be a laminated (stacked) electrode body formed by stacking multiple flat electrode plates, a bellows-type electrode body in which the electrode plates are folded in a bellows shape, or an electrode body of other shapes.

[0036] The current collectors 160 are conductive current collecting members (positive electrode current collector and negative electrode current collector) arranged on both sides of the electrode body 150 in the X-axis direction, connected (joined) to the terminal 140 and the electrode body 150, and electrically connecting the terminal 140 and the electrode body 150. The positive electrode current collector 160 is connected (joined) to the positive electrode plate of the electrode body 150 by welding or the like, and is connected (joined) to the positive electrode terminal 140 by crimping or the like, and is fixed to the lid body 130. The negative electrode current collector 160 is connected (joined) to the negative electrode plate of the electrode body 150 by welding or the like, and is connected (joined) to the negative electrode terminal 140 by crimping or the like, and is fixed to the lid body 130. The method of connecting (joining) the current collectors 160 and the electrode body 150 is not limited to welding, and crimping or the like may also be used. The positive electrode current collector 160 is formed of aluminum or an aluminum alloy, etc., similar to the current collecting foil of the positive electrode plate of the electrode body 150, and the negative electrode current collector 160 is formed of copper or a copper alloy, etc., similar to the current collecting foil of the negative electrode plate of the electrode body 150.

[0037] The gasket 170 is a plate-like, rectangular gasket that is disposed between the lid 130 of the container 110 and the terminal 140 and current collector 160, and provides insulation and sealing between the lid 130 and the terminal 140, as well as insulation between the lid 130 and the current collector 160 (see FIG. 4 , etc.). The gasket 170 is formed from an insulating material such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or a composite material thereof.

[0038] [3 Description of Terminal 140 of Energy Storage Element 100] Next, the configuration of the terminal 140 of the energy storage element 100 will be described in more detail. FIG. 3 is a plan view showing the configuration of the terminal 140 of the energy storage element 100 according to this embodiment. FIG. 3 is an enlarged view of a portion of the terminal 140 in the positive direction of the X-axis that the energy storage element 100 shown in FIG. 2 has, viewed from the positive direction of the Z-axis. FIG. 4 is a cross-sectional view showing the configuration of the terminal 140 of the energy storage element 100 according to this embodiment. FIG. 4 shows a cross-section of the configuration shown in FIG. 3 taken along a plane that includes line IV-IV passing through the center position in the Y-axis direction and is parallel to the XZ plane.

[0039] As shown in FIGS. 3 and 4 , the terminal 140 of the energy storage element 100 includes a terminal main body 141 and a terminal shank 142. The terminal main body 141 is a flat, rectangular portion parallel to the XY plane that constitutes the main body of the terminal 140. The terminal main body 141 is disposed in a position where the gasket 170 is sandwiched between the terminal main body 141 and the lid 130 in the positive Z-axis direction of the lid 130. The terminal shank 142 is a cylindrical portion (rivet portion) that extends in the negative Z-axis direction from the center of the surface of the terminal main body 141 in the negative Z-axis direction. The terminal shank 142 has a tip (end portion in the negative Z-axis direction) that is crimped while penetrating the gasket 170, the lid 130, and the current collector 160. This fixes the terminal 140, the current collector 160, and the gasket 170 to the lid 130. The terminal shaft portion 142 may have a recess formed at the end in the negative Z-axis direction, or may be a cylindrical portion (hollow rivet).

[0040] In this embodiment, the terminal 140 is a single-piece member in which the terminal body 141 and the terminal shank 142 are integrally formed (integrated). The positive electrode terminal 140 is formed as a single member from aluminum or an aluminum alloy, etc. The negative electrode terminal 140 is formed as a single member from nickel-plated copper or a copper alloy, etc. The terminal 140 may be formed such that the terminal body 141 and the terminal shank 142 are separate members. The negative electrode terminal 140 may be formed as two members, namely, the terminal body 141 formed from aluminum or an aluminum alloy, etc., and the terminal shank 142 formed from copper or a copper alloy, etc., and the terminal shank 142 may be press-fitted into the terminal body 141 from the negative Z-axis direction, for example. When the terminal body 141 and the terminal shank 142 are formed as two members, the terminal shank 142 may or may not penetrate the terminal body 141.

[0041] In this configuration, as described above, the terminal body 141 has an opposing surface 140a. The opposing surface 140a is the surface of the terminal body 141 in the positive direction of the Z axis (the top surface of the terminal 140). Furthermore, the opposing surface 140a has a mark portion 140c on which a marking is applied. In this embodiment, the mark portion 140c is located in the center (center position) of the opposing surface 140a when viewed from the Z axis direction. The mark portion 140c is located in the positive direction of the Z axis of the terminal shank 142. Hereinafter, a portion of the opposing surface 140a that is different from the mark portion 140c will be referred to as a non-mark portion 140b. The non-mark portion 140b is an annular portion that is located around the mark portion 140c so as to surround the periphery of the mark portion 140c.

[0042] The mark portion 140c is a recess in the opposing surface 140a that is recessed in the alignment direction (Z-axis direction) of the bus bar 200 and the terminal 140. The mark portion 140c is a recess that is recessed in the negative Z-axis direction relative to the non-mark portion 140b. In other words, the mark portion 140c is marked so that it can be distinguished from the non-mark portion 140b by its recess shape. In this embodiment, the mark portion 140c is a circular recess when viewed in the Z-axis direction. However, the shape of the mark portion 140c is not particularly limited, and may be an elliptical, oval, rectangular, or other polygonal shape when viewed in the Z-axis direction. The size of the mark portion 140c is also not particularly limited, but since the mark portion 140c functions as a positioning marker, it is preferable that the size of the mark portion 140c be neither too small nor too large.

[0043] In this embodiment, the mark portion 140c is smaller than the outer edge of the terminal shaft portion 142 when viewed in the Z-axis direction. When placing the busbar 200 on the terminal 140, the mark portion 140c serves as a reference coordinate. That is, the mark portion 140c is recognized by a camera, and the busbar 200 is positioned at a predetermined relative position with respect to the mark portion 140c, thereby positioning the busbar 200 on the terminal 140. If the position of the mark portion 140c recognized by the camera varies, the position of the busbar 200 also varies accordingly. As a result, the accuracy of positioning the busbar 200 on the terminal 140 decreases. After extensive research, the inventors of the present application found that a smaller area of ​​the mark portion 140c can suppress a decrease in the accuracy of positioning the busbar 200 on the terminal 140. Specifically, when viewed in the Z-axis direction, the minimum width of the mark portion 140c is preferably 1 mm or less, and the maximum width is more preferably 1 mm or less. When mark portion 140c is circular, a diameter of 1 mm or less is preferable. Furthermore, it has been found that the smaller the depth of mark portion 140c, the more effectively it is possible to suppress a decrease in the accuracy of positioning bus bar 200 above terminal 140. Specifically, the depth of mark portion 140c is preferably 0.5 mm or less.

[0044] The mark portion 140c can be formed by recessing the center of the opposing surface 140a of the terminal main body portion 141 using laser irradiation or a stamping machine. In this embodiment, a space is formed within the recess of the mark portion 140c, and no other members are placed therein. If another member is placed within the recess of the mark portion 140c, it is preferable that the other member be recessed further than the non-mark portion 140b so that the position of the mark portion 140c can be easily identified.

[0045] [4 Description of Positional Relationship Between Terminals 140 of Energy Storage Elements 100 and Bus Bar 200] Next, the positional relationship between the terminals 140 of the energy storage elements 100 and the bus bar 200 will be described in detail. FIG. 5 is a perspective view showing the configuration of the terminals 140 and bus bar 200 of the energy storage elements 100 according to this embodiment. FIG. 5 shows portions of two energy storage elements 100 in the positive direction of the X axis and the bus bar 200 connected to the terminals 140 of the two energy storage elements 100. FIG. 6 is a plan view showing the configuration of the terminals 140 and bus bar 200 of the energy storage elements 100 according to this embodiment. FIG. 6 is a view showing the configuration in which the bus bar 200 is connected to the terminals 140 of the two energy storage elements 100 shown in FIG. 5, as viewed from the positive direction of the Z axis. FIG. 7 is a cross-sectional view showing the configuration of the terminals 140 and bus bar 200 of the energy storage elements 100 according to this embodiment. Figure 7 shows a cross section of the configuration shown in Figure 6 when cut along a plane that includes line VII-VII passing through the center position of the storage element 100 in the Y-axis direction in the negative Y-axis direction and is parallel to the XZ plane.

[0046] As shown in FIGS. 5 to 7 , the busbar 200 has openings 210. The openings 210 are circular through-holes that penetrate the busbar 200 in the Z-axis direction. The busbar 200 has two openings 210 at positions facing the mark portions 140c of the terminals 140 of the two energy storage elements 100. The openings 210 are arranged so as to expose the mark portions 140c. That is, the mark portions 140c are arranged within the openings 210 when viewed from the alignment direction (Z-axis direction) of the busbar 200 and the terminals 140. As a result, the mark portions 140c are arranged at positions that do not overlap with the busbar 200 when viewed from the alignment direction (Z-axis direction). The openings 210 are not limited to a circular shape when viewed from the Z-axis direction, and may be elliptical, oval, rectangular, or other polygonal shapes, as long as they expose the mark portions 140c.

[0047] Opening 210 is preferably larger than mark portion 140c when viewed in the Z-axis direction in order to expose mark portion 140c, but if opening 210 is too large, the area for welding bus bar 200 and terminal 140 becomes smaller, which is not preferable. In the present embodiment, opening 210 is smaller than the outer edge shape of terminal shank 142 when viewed in the Z-axis direction.

[0048] The busbar 200 is longer in the X-axis direction than the width of the terminals 140, and longer in the Y-axis direction than the distance between the positive edge and the negative edge of two terminals 140 aligned in the Y-axis direction. As a result, the busbar 200 covers the outer edges of the terminals 140 when viewed from the direction in which the busbar 200 and the terminals 140 are aligned (the Z-axis direction). Specifically, the busbar 200 covers the entire periphery of the outer edges of the two terminals 140 aligned in the Y-axis direction when viewed from the Z-axis direction. In this embodiment, the busbar 200 is longer in the X-axis direction than the width of the gasket 170, and longer in the Y-axis direction than the distance between the positive edge and the negative edge of the two gaskets 170 aligned in the Y-axis direction when viewed from the Z-axis direction. As a result, the busbar 200 covers the entire periphery of the outer edges of the two gaskets 170 aligned in the Y-axis direction when viewed from the Z-axis direction.

[0049] As described above, the facing surface 140a of the terminal 140 of the energy storage element 100 faces the bus bar 200 and is in contact with the bus bar 200. The facing surface 140a faces the bus bar 200 in the Z-axis direction, and at least a portion of the facing surface 140a is in contact with the bus bar 200. Specifically, because the opening 210 is formed in the bus bar 200, the facing surface 140a is in contact with a portion of the bus bar 200 where the opening 210 is not formed (a portion of the non-mark portion 140b). Because the bus bar 200 covers the entire periphery of the outer edge of the terminal 140 when viewed from the Z-axis direction, the entire surface of the non-mark portion 140b that does not face the opening 210 is in contact with the bus bar 200. The bus bar 200 and the terminal 140 are joined (welded) in the region where they are in contact.

[0050] [5. Description of Effects] As described above, according to the energy storage device 10 according to the embodiment of the present invention, the terminals 140 of the energy storage elements 100 are provided with the mark portions 140c on the surfaces 140a facing the bus bar 200. The mark portions 140c are recessed in the alignment direction (Z-axis direction) of the bus bar 200 and the terminals 140, and are positioned so as not to overlap with the bus bar 200 as viewed from the alignment direction (Z-axis direction). Because the terminals 140 of the energy storage elements 100 are provided with the mark portions 140c, when connecting the bus bar 200 to the terminals 140 of the energy storage elements 100, the bus bar 200 can be easily positioned relative to the terminals 140 using the mark portions 140c as a guide. Because the mark portions 140c are recessed, it is possible to prevent the mark portions 140c from coming into contact with the bus bar 200 when connecting the bus bar 200 to the terminals 140. Because mark portion 140c does not overlap bus bar 200 when viewed from the arrangement direction (Z-axis direction), the position of mark portion 140c can be grasped from the arrangement direction (Z-axis direction) when connecting bus bar 200 to terminal 140. This makes it possible to easily connect bus bar 200 to terminal 140 of energy storage element 100. Since mark portion 140c can be used to improve the positioning accuracy of bus bar 200 relative to terminal 140, bus bar 200 can be easily connected to terminal 140 with high accuracy, and the accuracy of connecting (welding) bus bar 200 to terminal 140 of energy storage element 100 can be improved.

[0051] When viewed from the above-mentioned arrangement direction (Z-axis direction), mark portion 140c is disposed within opening 210 of bus bar 200. This allows the position of mark portion 140c to be ascertained from opening 210 of bus bar 200 when connecting bus bar 200 to terminal 140 of energy storage element 100.

[0052] Both the positive electrode terminal and the negative electrode terminal of the energy storage element 100 are provided with the mark portion 140c. This allows the bus bar 200 to be easily connected to both the positive electrode terminal and the negative electrode terminal using the mark portion 140c.

[0053] Because bus bar 200 covers the outer edges of terminals 140, it is difficult to grasp the position of the outer edges of terminals 140. However, even in this case, bus bar 200 can be easily positioned relative to terminals 140 by using mark portion 140c.

[0054] [6. Description of Modifications] While the energy storage device 10 according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0055] (Variation 1) In the above embodiment, mark portion 140c of terminal 140 of energy storage element 100 may be marked by color in addition to the shape of a recess. Fig. 8 is a plan view showing the configuration of terminal 140 of energy storage element 101 according to Variation 1 of the present embodiment. Fig. 8 is a view corresponding to Fig. 3 with an enlarged view of mark portion 140d and its surroundings added.

[0056] As shown in FIG. 8 , the terminal 140 of the energy storage element 101 in this modification includes a mark portion 140d instead of the mark portion 140c of the terminal 140 of the energy storage element 100 in the above embodiment. The mark portion 140d is a recessed portion that is a different color from the portion of the facing surface 140a that is different from the mark portion 140d. In other words, the mark portion 140d is a recessed portion that is a different color from the non-marked portion 140b. The mark portion 140d is marked so that it can be distinguished from the non-marked portion 140b by its recessed shape and color. The mark portion 140d can be formed by coloring the recessed portion in the center of the facing surface 140a of the terminal body 141 by printing with a printer, applying paint, attaching a label, or the like. The color of the mark portion 140d may be any color as long as it is different from the color of the non-marked portion 140b. Instead of the marked portion 140d, or together with the marked portion 140d, the non-marked portion 140b may be colored in a color different from that of the marked portion 140d.

[0057] In this modification, a space is formed within the recess of the mark portion 140d, and no other components are placed therein. If paint, a label, or the like is placed within the recess of the mark portion 140d, it is preferable that the paint, label, or the like be placed more recessed than the non-mark portion 140b so that the position of the mark portion 140d can be easily ascertained. When connecting the bus bar 200 to the terminal 140, as in the above embodiment, the mark portion 140d is placed in a position that does not overlap with the bus bar 200 when viewed from the Z-axis direction. As the other configurations of this modification are the same as those of the above embodiment, detailed description thereof will be omitted.

[0058] As described above, the energy storage device according to this modification can achieve the same effects as the above-described embodiment. In particular, in this modification, the mark portion 140d is a recess that has a different color from the other portions of the opposing surface 140a. By making the color of the mark portion 140d different in this way, the position of the mark portion 140d can be easily identified when connecting the bus bar 200 to the terminal 140 of the energy storage element 101.

[0059] (Modification 2) In the above embodiment, mark portion 140c is formed on terminal main body portion 141, but it may be formed on terminal shaft portion 142. Fig. 9 is a cross-sectional view showing the configuration of terminal 140 and bus bar 200 of energy storage element 102 according to modification 2 of the present embodiment. Fig. 9 is a view corresponding to Fig. 7.

[0060] As shown in FIG. 9 , the terminal 140 of the energy storage device 102 in this modification includes a terminal body 141a and a terminal shaft 142a instead of the terminal body 141 and the terminal shaft 142 included in the terminal 140 of the energy storage device 100 in the above embodiment. The terminal body 141a and the terminal shaft 142a are separate members. The terminal shaft 142a penetrates the terminal body 141a from the positive direction of the Z axis and is fixed to the terminal body 141a by press-fitting, crimping, or the like. The terminal body 141a is formed of aluminum or an aluminum alloy, or the like, and the terminal shaft 142a is formed of copper or a copper alloy, or the like. In this way, the terminal 140 in this modification is a negative terminal or the like composed of two members, the terminal body 141a and the terminal shaft 142a. As a result, the opposing surface 140a (non-mark portion 140b) of the terminal 140 is made up of the surface of the terminal body portion 141a facing in the positive Z-axis direction and the surface of the terminal shaft portion 142a facing in the positive Z-axis direction.

[0061] In this modified example, mark portion 140c is formed on terminal shank 142a. That is, mark portion 140c is formed on the surface of opposing surface 140a that is in the positive Z-axis direction of terminal shank 142a. Mark portion 140c is located in the center (central position) of terminal shank 142a when viewed from the Z-axis direction. When connecting bus bar 200 to terminal 140, mark portion 140c is located in a position that does not overlap bus bar 200 when viewed from the Z-axis direction, similar to the above embodiment. The other configurations of this modified example are also similar to those of the above embodiment, and therefore detailed description thereof will be omitted.

[0062] As described above, the energy storage device according to this modification can achieve the same effects as the above-described embodiment. Even when the terminal 140 is composed of two members, the terminal body portion 141a and the terminal shank portion 142a, as in this modification, the same configuration as the above-described embodiment can be applied. In particular, in this modification, the boundary portion between the terminal body portion 141a and the terminal shank portion 142a on the opposing surface 140a is used as the first mark, and the mark portion 140c is used as the second mark, thereby making it easier to connect the bus bar 200 to the terminal 140 of the energy storage element 102. In other words, by recognizing the first mark, the bus bar 200 can be brought closer to the terminal 140. If the first mark is hidden by the bus bar 200 when the bus bar 200 is placed on the terminal 140, the second mark (mark portion 140c) can be used for positioning. The opening 210 of the bus bar 200 may be formed larger than the terminal shank portion 142a so that the first mark is not hidden by the bus bar 200.

[0063] In this modification, terminal shank 142a may be recessed in the negative Z-axis direction relative to terminal body 141a. That is, facing surface 140a may have a shape in which the terminal shank 142a is recessed in the negative Z-axis direction, and marking portion 140c may be a recess recessed in the negative Z-axis direction from a portion of facing surface 140a recessed in the negative Z-axis direction. Terminal shank 142a may protrude in the positive Z-axis direction relative to terminal body 141a. That is, facing surface 140a may have a shape in which the terminal shank 142a is recessed in the positive Z-axis direction, and marking portion 140c may be a recess recessed in the negative Z-axis direction from a portion of facing surface 140a protruding in the positive Z-axis direction. In this case, in busbar 200, opening 210 may be formed larger than terminal shank 142a to avoid the protruding portion of terminal shank 142a, or a recess may be formed to accommodate the protruding portion of terminal shank 142a. In these cases, the same configuration as in the above embodiment can be applied, and the same effects as in the above embodiment can be achieved.

[0064] (Other Modifications) In the above embodiment, terminal 140 is a welded terminal joined to bus bar 200 by welding, but terminal 140 may be a bolt terminal or the like that includes a bolt portion formed with a male thread portion that protrudes in the positive direction of the Z axis and is joined to bus bar 200 by bolt connection. In this case, by including mark portion 140c on terminal 140, similar to the above embodiment, bus bar 200 can be easily positioned with respect to terminal 140 using mark portion 140c as a guide, and bus bar 200 can be easily connected to terminal 140 of energy storage element 100.

[0065] In the above embodiment, the bus bar 200 that connects two energy storage elements 100 and the connection configuration between the two energy storage elements 100 have been described, but the present invention is not limited to this. The configuration in the above embodiment may also be applied to the connection configuration between the energy storage elements 100 and the bus bar that connects the energy storage elements 100 and external terminals.

[0066] In the above embodiment, busbar 200 has opening 210, and mark portion 140c is arranged within opening 210 so as not to overlap busbar 200 when viewed from the Z-axis direction, but this is not limiting. Mark portion 140c may also be arranged to the side of busbar 200 so as not to overlap busbar 200 when viewed from the Z-axis direction. In this case, busbar 200 does not need to have opening 210.

[0067] In the above embodiment, when viewed from the Z-axis direction, bus bar 200 covers the entire periphery of the outer edges of two terminals 140 aligned in the Y-axis direction, but it is not necessary to cover a portion of the outer edge of any one of terminals 140, or it is not necessary to cover a portion of the outer edge of both terminals 140. Similarly, when viewed from the Z-axis direction, bus bar 200 covers the entire periphery of the outer edges of two gaskets 170 aligned in the Y-axis direction, but it is not necessary to cover a portion of the outer edge of any one of gaskets 170, or it is not necessary to cover a portion of the outer edge of both gaskets 170.

[0068] In the above embodiment, all of the multiple storage elements 100 and multiple bus bars 200 have the above configuration, but any one of the storage elements 100 or any one of the bus bars 200 may have a configuration different from the above.

[0069] In the above embodiment, both the positive and negative terminals of the energy storage element 100 are provided with the mark portion 140c, but it is also possible that either the positive or negative terminal does not have to be provided with the mark portion 140c.

[0070] In the above embodiment, a configuration including a plurality of energy storage elements 100 and a plurality of bus bars 200, etc., is referred to as the energy storage device 10, but a configuration including at least one energy storage element 100 can also be referred to as the energy storage device 10. A plurality of energy storage elements 100 may be referred to as the energy storage device 10, or one energy storage element 100 may be referred to as the energy storage device 10.

[0071] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0072] The present invention can be applied to an electricity storage device or the like that includes an electricity storage element such as a lithium ion secondary battery.

[0073] REFERENCE SIGNS LIST 10 Energy storage device 100, 101, 102 Energy storage element 110 Container 111 Long side wall portion 112 Short side wall portion 113 Bottom wall portion 120 Container body 130 Lid body 131 Gas release valve 140 Terminal 140a Opposing surface 140b Non-marked portion 140c, 140d Marked portion 141, 141a Terminal body portion 142, 142a Terminal shaft portion 150 Electrode body 160 Current collector 170 Gasket 200 Bus bar 210 Opening 300 Exterior body

Claims

1. An energy storage device comprising: an energy storage element having a terminal to which a bus bar is connected; the terminal having an opposing surface that faces the bus bar and makes contact with the bus bar; the opposing surface having a mark portion on which a mark is applied; the mark portion being a recess in the opposing surface that is recessed in the direction of alignment of the bus bar and the terminal, and positioned so as not to overlap the bus bar when viewed in the direction of alignment.

2. The energy storage device according to claim 1, wherein the bus bars have openings, and the markings are disposed within the openings when viewed from the arrangement direction.

3. The electricity storage device according to claim 1 or 2, wherein the mark portion is a recessed portion having a different color from a portion of the opposing surface that is different from the mark portion.

4. The energy storage device according to claim 1 or 2, wherein the energy storage element has a positive terminal and a negative terminal as the terminals, and both the positive terminal and the negative terminal have the mark portion.

5. The energy storage device according to claim 1 or 2, wherein the bus bar covers the outer edges of the terminals when viewed in the arrangement direction.

Images