Power storage element

Abstract

To provide a power storage element with improved reliability.SOLUTION: A power storage element includes a vessel 100, a terminal 200, and an electrode body 500, a current collector 400, a first insulating member 600, and a second insulating member 700 that are accommodated in the vessel. The current collector includes a connection part 412 to which the electrode body is connected. The vessel includes a first wall part 120 where the terminal is disposed, and a second wall part 111 that faces the connection part. The first insulating member and the second insulating member are disposed between the connection part and the second wall part. A part of the first insulating member and a part of the second insulating member overlap. An edge 601 of the first insulating member that faces the first wall part is closer to the first wall part than an edge 701 of the second insulating member that faces the first wall part.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an energy storage element. [Background technology]

[0002] Patent Document 1 discloses a prismatic energy storage element including a battery can and a wound electrode group housed in the battery can. In this prismatic energy storage element, a protective film made of an insulating material is wrapped around the wound electrode group with a central axis that is aligned with the flat surfaces of the wound electrode group and perpendicular to the winding axis of the wound electrode group. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-84666 Summary of the Invention [Problem to be solved by the invention]

[0004] In the energy storage element disclosed in Patent Document 1, for example, the position of the protective film may vary in the vertical direction, which may result in a decrease in the insulating performance of the protective film between the wound electrode group and the battery can.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problems, and has an object to provide an energy storage element with improved reliability. [Means for solving the problem]

[0006] An energy storage element according to one embodiment of the present invention comprises a container, a terminal, an electrode body, a current collector, a first insulating member, and a second insulating member housed in the container, the current collector having a connection portion to which the electrode body is connected, the container having a first wall portion on which the terminal is arranged, and a second wall portion facing the connection portion, the first insulating member and the second insulating member being arranged between the connection portion and the second wall portion, a portion of the first insulating member and a portion of the second insulating member overlapping, and the edge of the first insulating member facing the first wall portion being closer to the first wall portion than the edge of the second insulating member facing the first wall portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an energy storage element with improved reliability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of an energy storage device according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing the internal configuration of a container according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the first insulating member and the second insulating member according to the embodiment separated from the electrode body 500. As shown in FIG. [Figure 4] FIG. 4 is an exploded perspective view showing components other than the container body of the energy storage device according to the embodiment. [Figure 5] FIG. 5 is a first side view showing a partial configuration of an energy storage device according to an embodiment. [Figure 6] FIG. 6 is a second side view showing a partial configuration of the energy storage device according to the embodiment. [Figure 7] FIG. 7 is a third side view showing a partial configuration of an energy storage device according to an embodiment. [Figure 8] FIG. 8 is a side view of the configuration of the energy storage element shown in FIG. 7 when viewed from a different angle. [Figure 9] FIG. 9 is a cross-sectional view showing the difference in thickness between the first insulating member and the second insulating member according to the embodiment. [Figure 10] FIG. 10 is a plan view illustrating an example of a power storage device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (1) An energy storage element according to one embodiment of the present invention comprises a container, a terminal, an electrode body, a current collector, a first insulating member, and a second insulating member housed in the container, the current collector having a connection portion to which the electrode body is connected, the container having a first wall portion on which the terminal is arranged, and a second wall portion facing the connection portion, the first insulating member and the second insulating member being arranged between the connection portion and the second wall portion, a portion of the first insulating member and a portion of the second insulating member overlapping, and an edge of the first insulating member facing the first wall portion being closer to the first wall portion than an edge of the second insulating member facing the first wall portion.

[0010] In an energy storage device according to one aspect of the present invention, the first insulating member and the second insulating member cover the current collector with portions overlapping each other, and the upper edge of the first insulating member is positioned closer to the wall portion than the upper edge of the second insulating member. As a result, even if a gap occurs between the second insulating member and the first wall portion due to variation in the position of the second insulating member in the alignment direction of the first wall portion and the electrode body, the occurrence of insulation defects is suppressed. As a result, the reliability of the energy storage device is improved.

[0011] (2) In the energy storage device described in (1) above, the first insulating member may be attached to the connection portion and the electrode body.

[0012] According to the energy storage element described in (2) above, the first insulating member is attached to both the connecting portion of the current collector and the electrode body, and therefore the positional stability of the first insulating member is improved.

[0013] (3) In the energy storage device described in (1) or (2) above, the first insulating member may be disposed between the connection portion and the second insulating member.

[0014] According to the energy storage device described in (3) above, the area to which the first insulating member can be attached can be widened, thereby further improving the stability of the position of the first insulating member.

[0015] (4) In the energy storage device according to any one of (1) to (3) above, the second insulating member may be a rectangular parallelepiped insulating sheet that covers the electrode body.

[0016] According to the energy storage element described in (4) above, by covering most of the electrode body with the rectangular parallelepiped second insulating member, it is possible to insulate not only the current collector and its vicinity but also a wide area of ​​the electrode body from the container.

[0017] (5) In the energy storage device according to any one of (1) to (4) above, the thickness of the first insulating member may be smaller than the thickness of the second insulating member.

[0018] According to the energy storage element described in (5) above, the first insulating member can more reliably insulate the current collector from the container, and the use of the internal space of the container due to the placement of the first insulating member is suppressed.

[0019] Hereinafter, with reference to the drawings, an energy storage element according to an embodiment of the present invention (including its modified examples) will be described. The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection of the components, manufacturing processes, and the order of the manufacturing processes shown in the following embodiments are examples only 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 assigned the same reference numerals. Each drawing may be a schematic drawing in which emphasis, omission, or adjustment of proportions is appropriately made to illustrate the present invention.

[0020] In the following description and drawings, the X-axis direction is defined as the direction in which the second wall portions forming the short sides of the container of the energy storage element face each other, the direction in which the pair of terminals (positive and negative electrodes; the same applies hereinafter) of the energy storage element are aligned, the direction in which the pair of current collectors are aligned, the direction in which the connection portions of the current collectors face, the thickness (plate thickness) direction of the connection portions, the direction of the winding axis of the electrode assembly, or the longitudinal direction of the electrode assembly. The Y-axis direction is defined as the thickness direction of the container (the direction in which the width is smallest; the same applies hereinafter), the direction in which the third wall portions forming the long sides of the container face each other, the direction in which the two electrode assemblies are aligned, or the thickness direction of one electrode assembly. The Z-axis direction is defined as the direction in which the container body and the first wall portion serving as the lid of the container are aligned, the direction in which the first wall portion and the current collector or electrode assembly are aligned, the direction in which the electrode assembly and the terminal body are aligned, the direction in which the terminals protrude from the container, the direction in which the terminal connection portions of the current collectors face, the thickness (plate thickness) direction of the terminal connection portions, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in this embodiment). Depending on the mode of use, the Z-axis direction may not be the up-down direction, but for the sake of convenience, the following description will be given assuming that the Z-axis direction is the up-down direction.

[0021] In the following explanation, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the direction or attitude is not strictly that. When two directions are parallel (or perpendicular), it does not only mean that the two directions are completely parallel (or perpendicular), but also means that the directions are substantially parallel (or perpendicular), that is, there is a difference of, for example, a few percent. In the following explanation, when the term "insulation" is used, it means "electrical insulation." An insulating material has a volume resistivity of 1×10 10 It is preferable that the material be made of a material with a resistance of Ωm or more.

[0022] (Embodiment) [1. Description of the configuration of energy storage element 10] First, the configuration of an energy storage device 10 according to the present embodiment will be described in detail with reference to Figs. 1 to 4. Fig. 1 is a perspective view showing the appearance of an energy storage device 10 according to the embodiment. Fig. 2 is a perspective view showing the internal configuration of a container 100 according to the embodiment. Fig. 3 is a perspective view showing a first insulating member 600 and a second insulating member 700 according to the embodiment separated from an electrode body 500. Fig. 4 is an exploded perspective view showing components of an energy storage device 10 according to the embodiment other than a container body 110.

[0023] The energy storage device 10 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage device 10 is used as a battery for driving or starting the engine of a mobile object such as an automobile, a motorcycle, or an electric railway vehicle. Examples of such automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The energy storage device 10 can also be used as a stationary battery for home or business use.

[0024] The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may be a primary battery instead of a secondary battery. The energy storage element 10 may be a battery using a solid electrolyte. In the present embodiment, the energy storage element 10 is illustrated as having a rectangular parallelepiped (square) shape that is flattened in the Y-axis direction, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped, and may be a polygonal prism shape other than a rectangular parallelepiped, an elongated cylinder shape, an elliptical cylinder shape, a cylindrical shape, or the like.

[0025] As shown in FIG. 1, the energy storage element 10 includes a container 100, a pair of (positive and negative) terminals 200, and a pair of (positive and negative) upper gaskets 310. As shown in FIGS. 2 to 4, the energy storage element 10 further includes an electrode assembly 500, a first insulating member 600, a second insulating member 700, a pair of (positive and negative) lower gaskets 320, and a pair of (positive and negative) current collectors 400 housed inside the container 100. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but this 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 10, and various types can be selected. In addition to the above components, the energy storage element 10 may also include spacers or the like arranged on the sides or below the electrode assembly 500.

[0026] [1-1. Description of the container 100] As shown in FIGS. 1 and 2 , the container 100 is a rectangular parallelepiped (square or box-shaped) case including a container body 110 with an opening facing the positive direction of the Z axis and a first wall portion 120. The container body 110 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 100. The first wall portion 120 is a lid that closes the opening of the container body 110 and is a flat, rectangular member extending in the X axis direction. The first wall portion 120 is disposed in the positive direction of the Z axis of the container body 110. If the Z axis direction is defined as a first direction, the positive Z axis direction may be expressed as one side of the first direction, and the negative Z axis direction may be expressed as the other side of the first direction. In this case, the X axis direction may be expressed as a second direction intersecting with the first direction, and the Y axis direction may be expressed as a third direction intersecting with the first and second directions.

[0027] The container body 110 includes a pair of second wall portions 111 on both sides in the X-axis direction (short side surfaces), a pair of third wall portions 112 on both sides in the Y-axis direction (long side surfaces), and a bottom wall portion 113 on the surface in the negative Z-axis direction (bottom surface) (see FIG. 2). The second wall portion 111 is a flat, rectangular wall portion extending in the Z-axis direction. The second wall portion 111 is adjacent to the third wall portion 112, the bottom wall portion 113, and the first wall portion 120, and has a smaller area than the third wall portion 112. The third wall portion 112 is a flat, rectangular wall portion extending in the X-axis direction. The third wall portion 112 is adjacent to the second wall portion 111, the bottom wall portion 113, and the first wall portion 120, and has a larger area than the second wall portion 111. The bottom wall portion 113 is a flat, rectangular wall portion extending in the X-axis direction. The bottom wall portion 113 is disposed adjacent to the second wall portion 111 and the third wall portion 112. Depending on the shape of the container 100, the second wall portion 111 may be long in the Y-axis direction, the third wall portion 112 may be long in the Z-axis direction, or the bottom wall portion 113 may be long in the Y-axis direction.

[0028] After the electrode assembly 500 and the like are housed inside the container body 110, the container body 110 and the first wall portion 120 are joined by welding or the like, thereby sealing the interior of the container 100. The material of the container 100 (the container body 110 and the first wall portion 120) 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 100 may be formed of a laminate film or the like composed of multiple layers including a metal layer and a resin layer. The container body 110 and the first wall portion 120 may be formed of the same material or different materials. The container 100 (the first wall portion 120) may be provided with a liquid injection portion for injecting an electrolyte into the container 100 during the manufacture of the energy storage device 10, and a gas release valve for releasing pressure inside the container 100 if the pressure inside the container 100 increases excessively.

[0029] [1-2. Description of Terminal 200, Upper Gasket 310, and Lower Gasket 320] The terminals 200 are electrode terminals (positive and negative terminals) electrically connected to the electrode assembly 500 via the current collector 400. The terminals 200 are metal members that conduct electricity stored in the electrode assembly 500 to the external space of the energy storage element 10 and also introduce electricity into the internal space of the energy storage element 10 in order to store electricity in the electrode assembly 500.

[0030] Terminal 200 includes a terminal body disposed in the positive direction of the Z axis relative to first wall 120, and a shaft portion 201 extending from the terminal body in the negative direction of the Z axis and penetrating first wall 120. Terminal 200 is formed of a conductive material such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. Terminal 200 is connected (joined) to current collector 400 by crimping, welding, or the like, and is attached to first wall 120. Terminal 200 is disposed in a state protruding in the positive direction of the Z axis from the outer surface (the surface facing the positive direction of the Z axis) of first wall 120. In this embodiment, terminal 200 is a welded terminal joined to an external conductive member, such as a bus bar, by welding. However, terminal 200 may also be a bolt terminal including a bolt portion formed with a male thread protruding in the positive direction of the Z axis and joined to the conductive member by bolt fastening.

[0031] In this embodiment, two terminals 200 (a positive terminal 200 and a negative terminal 200) are arranged side by side in the X-axis direction. Hereinafter, when distinguishing between these two terminals 200, one (the terminal 200 located in the positive direction of the X-axis) will be referred to as a first terminal 210, and the other (the terminal 200 located in the negative direction of the X-axis) will be referred to as a second terminal 220. In this embodiment, the first terminal 210 is the positive terminal 200 (positive terminal), and the second terminal 220 is the negative terminal 200 (negative terminal).

[0032] The upper gasket 310 is a plate-like, rectangular gasket that is disposed between the first wall 120 of the container 100 and the terminal 200 and provides insulation and sealing between the first wall 120 and the terminal 200. The lower gasket 320 is a plate-like, rectangular gasket that is disposed between the first wall 120 and the current collector 400 and provides insulation between the first wall 120 and the current collector 400. The upper gasket 310 and the lower gasket 320 can be made of any suitable known material, such as an insulating material such as resin.

[0033] [1-3. Description of the electrode body 500] The electrode assembly 500 is an electricity storage element (power generating element) that can store electricity and is formed by stacking positive and negative electrode plates and separators. The electrode assembly 500 is a wound-type electrode assembly formed by winding the positive and negative electrode plates and separators around a winding axis extending in the X-axis direction. The winding axis is an imaginary axis that serves as the central axis when winding the positive and negative electrode plates, etc., and in this embodiment, it is a straight line that passes through the center of the electrode assembly 500 and is parallel to the X-axis direction. In this embodiment, the electrode assembly 500 has an elongated shape that extends in the X-axis direction and has a substantially oval cylindrical shape (an oval shape when viewed from the X-axis direction). The shape of the electrode assembly 500 is not particularly limited and may be a substantially cylindrical shape or a substantially elliptical cylindrical shape, and the length of the electrode assembly 500 in the X-axis direction is also not particularly limited. The electrode assembly 500 may be elongated in the Z-axis direction.

[0034] The positive electrode plate is an 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 current collector foil (metal 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 the surface of a negative electrode current collector foil, which is a long, strip-shaped current collector foil (metal foil) made of a metal such as copper or a copper alloy. Any known material can be used for the positive electrode current collector foil and the negative electrode current collector foil as long as it is stable against oxidation-reduction reactions during charging and discharging. Any known material can be used for 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-transporting ions.

[0035] The separator is a microporous insulating sheet made of resin or the like. Any known material can be used as the separator material as long as it does not impair the performance of the energy storage element 10. Examples of separator materials include woven fabric, nonwoven fabric, and porous resin film.

[0036] The positive electrode plate has multiple tabs (positive electrode tabs) protruding to one side in the X-axis direction, and by winding the positive electrode plate, a positive electrode tab portion is formed in which the multiple tabs (positive electrode tabs) overlap. The negative electrode plate has multiple tabs (negative electrode tabs) protruding to the other side in the X-axis direction, and by winding the negative electrode plate, a negative electrode tab portion is formed in which the multiple tabs (negative electrode tabs) overlap. As a result, the electrode body 500 has an electrode body main body 510 and tab portions 520 protruding from the electrode body main body 510 on one and the other sides in the X-axis direction of the electrode body main body 510. The electrode body main body 510 is the main body of the electrode body 500, and is an elongated cylindrical portion formed by winding the portions of the positive and negative electrode plates other than the tabs and the separator. In this embodiment, when distinguishing between the pair of tab portions 520 protruding from the electrode body main body portion 510, the tab portion 520 protruding from the electrode body main body portion 510 in the positive direction of the X-axis is referred to as a first tab portion 521, and the tab portion 520 protruding from the electrode body main body portion 510 in the negative direction of the X-axis is referred to as a second tab portion 523. In this embodiment, the first tab portion 521 is the tab portion of the positive electrode, and the second tab portion 523 is the tab portion of the negative electrode.

[0037] In this embodiment, the energy storage element 10 includes two electrode bodies 500. The two electrode bodies 500 are aligned in the Y-axis direction as shown in FIGS. 3 and 4. As a result, the two first tab portions 521 are aligned in the Y-axis direction, and the two second tab portions 523 are aligned in the Y-axis direction. The two first tab portions 521 aligned in the Y-axis direction are connected to the positive electrode current collector 400. As a result, the two first tab portions 521 are electrically connected to the first terminal 210 via the positive electrode current collector 400. The two second tab portions 523 aligned in the Y-axis direction are connected to the negative electrode current collector 400. As a result, the two second tab portions 523 are electrically connected to the second terminal 220 via the negative electrode current collector 400.

[0038] [1-4. Description of the current collector 400] The current collectors 400 are conductive current collecting members (positive electrode current collector and negative electrode current collector) that are disposed on both sides of the electrode assembly 500 in the X-axis direction and are connected (joined) to the electrode assembly 500 and the terminal 200, electrically connecting the electrode assembly 500 and the terminal 200. The current collectors 400 have a shape formed by bending a single plate-like member. In other words, the current collector 400 is an L-shaped member when viewed from the Y-axis direction. The current collector 400 has a simple configuration and is therefore easy to manufacture. Because the current collector 400 can be formed from a single plate-like member, there is no need to provide a separate lead, etc., and the number of parts can be reduced. Furthermore, by reducing the space occupied by the current collectors 400 (space saving), the capacity of the energy storage element 10 can be improved.

[0039] More specifically, the current collector 400 includes a terminal connection portion 411 that is connected to the terminal 200, and a connection portion 412 that is connected to the electrode body 500. The terminal connection portion 411 and the connection portion 412 are both flat plate-shaped, and are connected to form an L-shape as described above.

[0040] The terminal connection portion 411 is a flat, rectangular portion parallel to the XY plane. The terminal connection portion 411 is connected to the terminal 200 by, for example, crimping. The terminal connection portion 411 is arranged in the negative Z-axis direction of the first wall portion 120 and has a through-hole 401 through which a shank 201 (see FIG. 4) of the terminal 200 passes. The shank 201 is a rivet portion extending in the negative Z-axis direction from the terminal body of the terminal 200. The shank 201 is inserted into the through-hole 311 of the upper gasket 310, the through-hole 121 of the first wall portion 120, the through-hole 321 of the lower gasket 320, and the through-hole 401 of the terminal connection portion 411, and crimped (see FIG. 5). As a result, the current collector 400 is fixed to the first wall portion 120 together with the terminal 200. The method for connecting the current collector 400 and the terminal 200 is not limited to crimping, and welding such as ultrasonic welding, laser welding, or resistance welding, or mechanical joining other than crimping such as screw connection may also be used.

[0041] In this embodiment, two current collectors 400 (a positive electrode current collector 400 and a negative electrode current collector 400) are arranged side by side in the X-axis direction. Hereinafter, of the two current collectors 400, the current collector 400 located in the positive direction of the X-axis will be referred to as a first current collector 410, and the current collector 400 located in the negative direction of the X-axis will be referred to as a second current collector 420. In this embodiment, the first current collector 410 is the positive electrode current collector 400, and the second current collector 420 is the negative electrode current collector 400. That is, as shown in FIG. 4 , the first current collector 410 is connected to the first terminal 210, and the second current collector 420 is connected to the second terminal 220. The first current collector 410 (positive electrode current collector) is formed of aluminum, an aluminum alloy, or the like, similar to the positive electrode current collector foil of the electrode assembly 500. The second current collector 420 (negative electrode current collector) is formed of copper, a copper alloy, or the like, similar to the negative electrode current collector foil of the electrode assembly 500.

[0042] Tab portions 520 of the electrode assembly 500 are connected to the connection portions 412 of these two current collectors 400. As shown in FIGS. 3 and 4 , the connection portions 412 of the current collectors 400 are flat, rectangular portions parallel to the XY plane, and the tab portions 520 of the electrode assembly 500 are connected by ultrasonic welding or the like. More specifically, two first tab portions 521 of the two electrode assemblies 500 are connected to the connection portion 412 of the first current collector 410. Two second tab portions 523 of the two electrode assemblies 500 are connected to the connection portion 412 of the second current collector 420. Methods for connecting the connection portions 412 and the tab portions 520 include ultrasonic welding, welding such as laser welding and resistance welding, or mechanical joining such as crimping or screw joining.

[0043] 2. Configuration of the First Insulating Member 600 and the Second Insulating Member 700 Next, the configurations of the first insulating member 600 and the second insulating member 700 will be described with reference to Figures 5 to 9 in addition to Figures 2 to 4. In the following, attention will be focused on the first insulating member 600 in the negative X-axis direction of the two first insulating members 600, and the configuration of the first insulating member 600 and its surroundings will be mainly described.

[0044] FIG. 5 is a first side view showing a partial configuration of the energy storage device 10 according to the embodiment. FIG. 5 schematically shows a partial configuration of the energy storage device 10 before the first insulating member 600 and the second insulating member 700 are arranged, and the container body 110 is not shown. FIG. 6 is a second side view showing a partial configuration of the energy storage device 10 according to the embodiment. FIG. 6 schematically shows a partial configuration of the energy storage device 10 in a state in which the first insulating member 600 is arranged, and the container body 110 is not shown. FIG. 7 is a third side view showing a partial configuration of the energy storage device 10 according to the embodiment. FIG. 7 schematically shows a partial configuration of the energy storage device 10 in a state in which the first insulating member 600 and the second insulating member 700 are arranged, and the container body 110 is shown in cross section. FIGS. 5 to 7 show side views of the configuration of the energy storage device 10 as viewed from the negative Y-axis direction. FIG. 8 is a side view of the configuration of the energy storage device 10 shown in FIG. 7 as viewed from another angle. Fig. 8 shows a side view of the configuration of energy storage device 10 shown in Fig. 7 as seen from the negative X-axis direction. Fig. 9 is a cross-sectional view showing the difference in thickness between first insulating member 600 and second insulating member 700 according to the embodiment.

[0045] 3, 6, and 7, in the energy storage device 10 according to the present embodiment, a first insulating member 600 and a second insulating member 700 are disposed between the electrode body 500 and the current collector 400 and the inner surface of the container 100. The first insulating member 600 and the second insulating member 700 are sheet- or film-shaped members containing, as a main material, an insulating resin such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), or polyethylene terephthalate (PET).

[0046] In this embodiment, the first insulating members 600 are disposed corresponding to the two current collectors 400 (first current collector 410 and second current collector 420). For example, as shown in Fig. 3 and Figs. 6 to 8, the first insulating members 600 in the negative X-axis direction are disposed so as to surround the end of the current collector 400 in the positive Z-axis direction from three directions (the negative X-axis direction, the positive Y-axis direction, and the negative Y-axis direction).

[0047] Specifically, the first insulating member 600 includes a first insulating portion 602 and first side surface portions 603 connected to both ends of the first insulating portion 602 in the Y-axis direction. The first insulating portion 602 is disposed between the current collector 400 and the inner surface of the container body 110. More specifically, at least a portion of the first insulating portion 602 is disposed between the connection portion 412 of the current collector 400 and the second wall portion 111. At least a portion of the first side surface portion 603 is disposed between the electrode assembly 500 and the third wall portion 112 of the container 100 (see FIGS. 2 and 8). The first insulating member 600 configured in this manner is disposed relatively close to the first wall portion 120 of the container 100 in the Z-axis direction, as shown in FIGS. 6 to 8. That is, the distance between the edge 601 of the first insulating member 600 facing the first wall portion 120 (i.e., the edge in the positive direction of the Z-axis) and the first wall portion 120 is relatively short (including the case where the distance is zero).

[0048] In the energy storage device 10 according to this embodiment, in addition to the first insulating member 600 configured as described above, a second insulating member 700 configured to encase the electrode assembly 500 is disposed inside the container 100. Specifically, the second insulating member 700 includes a pair of second insulating portions 702 facing each other in the X-axis direction and a pair of second side surface portions 703 facing each other in the Y-axis direction (see FIG. 3). At least a portion of the second insulating portion 702 is disposed between the connection portion 412 of the current collector 400 and the second wall portion 111 of the container 100 (see FIGS. 2 and 7). At least a portion of the second side surface portion 703 is disposed between the electrode assembly 500 and the third wall portion 112 of the container 100 (see FIGS. 2 and 8). As a result, the second insulating member 700 is arranged in a state in which it wraps around the electrode assembly 500 (two electrode assemblies 500 in this embodiment) from both sides in the direction of the winding axis of the electrode assembly 500 (the X-axis direction in this embodiment) and from both sides in the flat direction of the electrode assembly 500 (the Y-axis direction in this embodiment). The second insulating member 700 in this embodiment can be obtained, for example, by wrapping a long strip-shaped insulating sheet around the electrode assembly 500 (two electrode assemblies 500 in this embodiment) and fixing the outermost peripheral end with a fixing member (not shown) such as adhesive tape. The configuration of the second insulating member 700 is not limited to this, and a seamless cylindrical second insulating member 700 may also be produced, for example, by resin molding using a mold.

[0049] 2 and 6 to 9, a portion of the second insulating member 700 configured in this manner overlaps a portion of the first insulating member 600 in the thickness direction of the second insulating member 700 (and in the thickness direction of the first insulating member 600). In other words, the second insulating member 700 has an overlapping portion 750 (see FIGS. 7 and 8) that overlaps with the first insulating member 600. In this embodiment, the second insulating member 700 has the overlapping portion 750 on both the second insulating portion 702 and the second side surface portion 703.

[0050] The second insulating member 700, which has the overlapping portion 750 that overlaps with the first insulating member 600 as described above, is disposed at a position relatively far from the first wall portion 120 of the container 100 in the Z-axis direction. In other words, it can be said that the distance between the first wall portion 120 and an edge 701, which is the edge of the second insulating member 700 that faces the first wall portion 120 (i.e., the edge in the positive direction of the Z-axis), and the edge 701 is relatively long. More specifically, in the arrangement direction of the first wall portion 120 and the electrode assembly 500 (the Z-axis direction in this embodiment), the edge 701 of the second insulating member 700 is disposed at a position farther from the first wall portion 120 than the edge 601 of the first insulating member 600. In other words, it is not necessary to dispose the edge 701 of the second insulating member 700 that encases the electrode assembly 500 as described above close to the first wall portion 120, which is the lid of the container 100. Therefore, for example, high accuracy is not required for the position of the second insulating member 700 in the Z-axis direction, and variation in position in the Z-axis direction is allowed within a predetermined range. However, in this case, a gap between the edge 701 of the second insulating member 700 and the first wall portion 120 in the Z-axis direction can cause poor insulation between the electrode assembly 500 and / or the current collector 400 and the container 100. In this regard, in the energy storage device 10 according to this embodiment, the first insulating member 600 is arranged so as to fill at least a portion of the gap (see FIGS. 2, 7, and 8). This prevents the occurrence of the above-mentioned poor insulation.

[0051] As described above, the energy storage element 10 according to this embodiment includes the container 100, the terminal 200, and the electrode assembly 500, current collector 400, first insulating member 600, and second insulating member 700 housed in the container 100. The current collector 400 includes a connection portion 412 to which the electrode assembly 500 is connected. The container 100 includes a first wall portion 120 on which the terminal 200 is disposed, and a second wall portion 111 facing the connection portion 412. The first insulating member 600 and the second insulating member 700 are disposed between the connection portion 412 and the second wall portion 111. A portion of the first insulating member 600 and a portion of the second insulating member 700 overlap. The edge 601 of the first insulating member 600 facing the first wall portion 120 is closer to the first wall portion 120 than the edge 701 of the second insulating member 700 facing the first wall portion 120.

[0052] Thus, in the energy storage device 10 according to the present embodiment, the first insulating member 600 and the second insulating member 700 cover the current collector 400 with portions overlapping each other, and the edge 601, which is the upper edge of the first insulating member 600, is positioned closer to the first wall portion 120 than the edge 701, which is the upper edge of the second insulating member 700. As a result, even if a gap occurs between the second insulating member 700 and the first wall portion 120 due to variations in the position of the second insulating member 700, the occurrence of insulation defects is suppressed. As a result, the reliability of the energy storage device 10 is improved.

[0053] More specifically, if the second insulating member 700, which is disposed along a relatively wide range of the electrode assembly 500, is disposed close to the first wall portion 120, a problem is likely to occur in which the edge 701 of the second insulating member 700 is pinched between the first wall portion 120 and the opening when the opening of the container body 110 is closed with the first wall portion 120. In this regard, in the energy storage device 10 according to this embodiment, the second insulating member 700 is disposed so that its edge 701 is located far from the first wall portion 120. This makes it less likely that problems such as pinching will occur. As a result, for example, the energy storage device 10 can be manufactured efficiently. In this embodiment, the first insulating member 600, which has a portion overlapping with the second insulating member 700, is further disposed so that its edge 601 is located close to the first wall portion 120. As a result, at least a part of the gap between the second insulating member 700 and the first wall portion 120, which occurs because the edge 701 of the second insulating member 700 is far from the first wall portion 120, is filled with the first insulating member 600. As a result, the occurrence of insulation failure due to the gap is suppressed.

[0054] In the present embodiment, as described above, the first insulating member 600, which fills the gap between the second insulating member 700 and the first wall portion 120, is attached to a member disposed inside the container 100. More specifically, the first insulating member 600 is attached to the connecting portion 412 and the electrode body 500. This improves the stability of the position of the first insulating member 600.

[0055] The first insulating member 600 is realized by, for example, an adhesive tape having an adhesive layer formed on one side of a resin base material. In the present embodiment, the first insulating member 600 is attached to the connection portion 412 of the current collector 400. That is, the first insulating portion 602 of the first insulating member 600 facing the connection portion 412 includes a first attachment portion 602a (see FIG. 6) that is attached to the connection portion 412. In the present embodiment, the first insulating member 600 is also attached to a surface of the electrode body 500 in the thickness direction (Y-axis direction). That is, the first side surface portion 603 of the first insulating member 600 facing the electrode body 500 in the thickness direction (Y-axis direction) includes a second attachment portion 603a (see FIG. 6) that is attached to the electrode body 500. In this way, since the first insulating member 600 is attached to both the current collector 400 and the electrode body 500, for example, displacement of the first insulating member 600 after attachment is more reliably suppressed. Therefore, even if the first insulating member 600 is positioned close to the first wall portion 120, the problem of the edge 601 of the first insulating member 600 being pinched between the first wall portion 120 and the opening of the container body 110 is unlikely to occur.

[0056] When the first insulating member 600 is affixed to a member inside the container 100, it does not have to be affixed to both the connection portion 412 and the electrode assembly 500. For example, the first insulating member 600 may be affixed to only one of the connection portion 412 and the electrode assembly 500. The member to which the first insulating member 600 is affixed may be a member other than the current collector 400 and the electrode assembly 500, such as the lower gasket 320.

[0057] The first insulating member 600 may be realized, for example, by a double-sided adhesive tape in which adhesive layers are formed on both sides of a resin base material. In this case, the first insulating member 600 may be attached to the connecting portion 412 and the electrode body 500, as well as to the overlapping portion 750 of the second insulating member 700. This may improve the stability of the position of the second insulating member 700.

[0058] In this embodiment, the overlapping order of the first insulating member 600 and the second insulating member 700, which have overlapping portions, is described as follows: In other words, in the energy storage device 10 according to this embodiment, the first insulating member 600 is disposed between the connecting portion 412 and the second insulating member 700.

[0059] In other words, simply put, the second insulating member 700 is disposed on the outside of the first insulating member 600. This allows the area over which the first insulating member 600 can be attached to be widened. More specifically, the first insulating member 600 can be disposed on the electrode body 500 and the current collector 400 before the second insulating member 700 is disposed on the electrode body 500 and the current collector 400. Therefore, the first insulating member 600 can be attached to the electrode body 500 and the current collector 400 without being hindered by the presence of the second insulating member 700. As a result, the first insulating member 600 can be attached over a wide area, which further improves the stability of the position of the first insulating member 600.

[0060] In this embodiment, the second insulating member 700 has a rectangular parallelepiped shape and is an insulating sheet that covers the electrode body 500 .

[0061] In this way, since a rectangular parallelepiped insulating sheet is used as the second insulating member 700, most of the electrode body 500 can be covered by the second insulating member 700. This makes it possible to insulate not only the current collector 400 and its vicinity but also a wide range of the electrode body 500 from the container 100.

[0062] In this embodiment, for example, as shown in Fig. 9, the thickness W1 of the first insulating member 600 is smaller than the thickness W2 of the second insulating member 700. For example, <W1<0.1mmであり、かつ、0.05mm<W2<0.5mmである。

[0063] According to this configuration, the first insulating member 600 can insulate the current collector 400 and the container 100 more reliably, and the use of the internal space of the container 100 due to the placement of the first insulating member 600 is suppressed.

[0064] 3. Energy Storage Device 900 Including Energy Storage Element 10 The energy storage element 10 according to the present embodiment may be used in an energy storage device. In this case, the technology of the present invention may be applied to at least one energy storage element 10 included in the energy storage device. FIG. 10 is a plan view showing an example of an energy storage device 900 according to the embodiment. As shown in FIG. 10, a plurality of energy storage units 800 are arranged inside the energy storage device 900. The energy storage unit 800 is composed of a plurality of electrically connected energy storage elements 10. The energy storage device 900 may include a bus bar (not shown) that electrically connects the plurality of energy storage elements 10, a bus bar (not shown) that electrically connects the plurality of energy storage units 800, and the like. The energy storage unit 800 or the energy storage device 900 may include a state monitoring device (not shown) that monitors the state of one or more energy storage elements 10. The energy storage device 900 may include only one energy storage unit 800. In other words, the energy storage unit 800 may be referred to as an energy storage device.

[0065] [4. Explanation of Modifications] Although 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 illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0066] The ranges in which the first insulating member 600 and the second insulating member 700 are arranged are not limited to the ranges shown in FIGS. 2, 3, and 5 to 8. For example, each of the first insulating member 600 and the second insulating member 700 may only be a portion that is arranged along the second wall portion 111 of the container body 110 (see FIGS. 2 and 7). Even in this case, the condition that a portion of the first insulating member 600 and a portion of the second insulating member 700 overlap and that the edge 601 of the first insulating member 600 is closer to the first wall portion 120 than the edge 701 of the second insulating member 700 can be satisfied. This makes it possible to suppress insulation defects at least between the second wall portion 111 of the container body 110 and the electrode assembly 500 and current collector 400 by the portion of the first insulating member 600 and the second insulating member 700.

[0067] The shape of the current collector 400 does not have to be the shape shown in Fig. 4. The current collector 400 may have, for example, two plate-like portions corresponding to the two electrode bodies 500, the two plate-like portions being spaced apart in the Y-axis direction, as a connection portion connected to the two electrode bodies 500. The connection portion 412 of the current collector 400 may be oriented so that its thickness direction faces the Y-axis direction. In this case, the tab portion 520 of the electrode body 500 may be connected to the connection portion 412 in a state where it extends in the X-axis direction (see Fig. 4).

[0068] The first insulating member 600 may be disposed on the outside of the second insulating member 700. For example, the second insulating member 700 may be disposed on the electrode body 500 and the current collector 400, and then the first insulating member 600 may be disposed on the electrode body 500 and the current collector 400. In this case, the first insulating member 600 may be attached to an end portion of the second insulating member 700, including an edge 701 (see FIGS. 7 and 8 ), and to at least one of the electrode body 500 and the current collector 400. In this case, the first insulating member 600 may function as a member that fixes the end portion of the second insulating member 700 to at least one of the electrode body 500 and the current collector 400.

[0069] 6 to 8, the first insulating member 600 and the first wall portion 120 are spaced apart in the Z-axis direction, but the first insulating member 600 may be disposed in contact with the first wall portion 120. In this case, an edge 601 of the first insulating member 600 may be connected to the first wall portion 120 by an adhesive layer provided on the first insulating member 600. The contact between the first insulating member 600 and the first wall portion 120 further improves the insulation between, for example, the container 100 and the terminal connection portion 411 of the current collector 400.

[0070] The thickness W1 of the first insulating member 600 may be equal to or greater than the thickness W2 of the second insulating member 700. For example, the thickness W1 of the first insulating member 600 may be approximately 1 mm, and the thickness W2 of the second insulating member 700 may be approximately 0.5 mm. When the thickness W2 of the second insulating member 700, which covers most of the electrode assembly 500, is relatively small, it is possible to increase, for example, the proportion of the volume of the electrode assembly 500 in the volume inside the container 100.

[0071] The first wall 120 does not need to be a lid that closes the opening of the container body 110. For example, when the terminal 200 is disposed on the bottom wall 113 of the container body, the bottom wall 113 may be treated as the "first wall."

[0072] The number of electrode bodies 500 included in the energy storage device 10 is not limited to two. The energy storage device 10 may include only one electrode body 500. The energy storage device 10 may include, for example, three or more electrode bodies 500 arranged in the Y-axis direction.

[0073] The electrode body 500 does not need to include the tab portion 520. For example, the end portion in the X-axis direction of the electrode body 500 (the portion protruding in the X-axis direction from the entire edge of the electrode body main body portion 510 in the X-axis direction) may be connected to the connection portion 412 of the current collector 400 by ultrasonic bonding or the like.

[0074] In Figures 5 to 7, the tab portion 520 is arranged and connected to the outside of the current collector 400 (negative direction of the X-axis), but the tab portion 520 may also be arranged and connected to the inside of the current collector 400 (positive direction of the X-axis).

[0075] The electrode body 500 is not limited to a wound type electrode body. The electrode body 500 may be a laminated type (stack type) electrode body formed by stacking a plurality of flat electrode plates, a bellows type electrode body in which electrode plates are folded in a bellows shape, or an electrode body of another form.

[0076] In the above embodiment, the wall portions (second wall portion 111, third wall portion 112, etc.) of the container 100 are flat walls, but they may also be walls having at least a partially curved shape.

[0077] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention. [Industrial Applicability]

[0078] The present invention can be applied to an electric storage device such as a lithium ion secondary battery. [Explanation of symbols]

[0079] 10. Energy storage element 100 containers 110 Container body 111 Second wall 112 Third wall 113 Bottom wall 120 First wall 121, 311, 321, 401 through holes 200 terminals 201 Shaft 210 First terminal 220 Second terminal 310 Upper gasket 320 Lower Gasket 400 current collector 410 First current collector 411 Terminal connection part 412 Connection 420 Second current collector 500 electrode body 510 Electrode body part 520 Tab section 521 First tab part 523 Second tab part 600 First insulating member 601 Edge 602 First insulation section 602a First attachment part 603 First side part 603a Second attachment part 700 Second insulating member 701 Edge 702 Second insulation section 703 Second side part 750 overlapping parts 800 Energy Storage Unit 900 Electricity storage device

Claims

1. A container and The terminal and an electrode assembly, a current collector, a first insulating member, and a second insulating member housed in the container; the current collector has a connection portion to which the electrode body is connected, the container includes a first wall portion in which the terminal is disposed and a second wall portion facing the connection portion, the first insulating member and the second insulating member are disposed between the connection portion and the second wall portion, a portion of the first insulating member overlaps a portion of the second insulating member, an edge of the first insulating member facing the first wall portion is closer to the first wall portion than an edge of the second insulating member facing the first wall portion; Energy storage element.

2. The first insulating member is attached to the connection portion and the electrode body. The energy storage element according to claim 1.

3. the first insulating member is disposed between the connection portion and the second insulating member; The energy storage element according to claim 1 or 2.

4. The second insulating member has a rectangular parallelepiped shape and is an insulating sheet that covers the electrode body. The energy storage element according to claim 1 or 2.

5. The thickness of the first insulating member is smaller than the thickness of the second insulating member. The energy storage element according to claim 1 or 2.

Images