storage element

Abstract

The power storage element includes an electrode body formed by winding an electrode plate, and a sheet member fixed to an outermost circumference of the electrode body, the sheet member having a higher tensile rigidity than the electrode plate.

Description

Technical Field

[0001] This invention relates to energy storage components. Background Technology

[0002] Patent Document 1 discloses a lithium-ion secondary battery having a wound electrode assembly formed by winding positive electrode sheets and negative electrode sheets with spacers between them, and a battery container for housing the wound electrode assembly. The lithium-ion secondary battery has a stretchable rubber-like insulating resin sheet between the wound electrode assembly and the battery container.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-73809 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The electrode body formed by winding the electrode plates expands with the use of the energy storage element, and there is a risk of damage due to this expansion. It is desirable to suppress such damage. In the lithium-ion secondary battery disclosed in the aforementioned Patent Document 1, a stretchable rubber-like insulating resin sheet is provided for the purpose of preventing short circuits when a metal foreign object pierces or penetrates it. This sheet is not used to suppress damage caused by the expansion of the wound electrode assembly.

[0008] This invention was made by the inventors of this application with regard to the above-mentioned problems, and its purpose is to provide an energy storage element that can suppress damage to the electrode body.

[0009] Technical means to solve the problem

[0010] One aspect of the present invention relates to an energy storage element having an electrode body formed by winding an electrode plate, and a sheet member fixed to the outermost periphery of the electrode body, the sheet member having a higher tensile stiffness than the electrode plate.

[0011] Invention Effects

[0012] The energy storage element according to the present invention can suppress damage to the electrode body. Attached Figure Description

[0013] Figure 1 This is a perspective view showing the appearance of the energy storage element involved in the embodiment.

[0014] Figure 2 This is a perspective view showing the structural elements of the energy storage element involved in the exploded embodiment.

[0015] Figure 3This is a perspective view showing the structure of the electrode body involved in the embodiment.

[0016] Figure 4 This is a cross-sectional view showing the structure of the electrode body involved in the embodiment.

[0017] Figure 5 This is a perspective view showing the structure of the electrode body and sheet component involved in the embodiment.

[0018] Figure 6 This is a cross-sectional view showing the structure of the electrode body and sheet component involved in the embodiment.

[0019] Figure 7 This is a cross-sectional view used to illustrate how the sheet component involved in the embodiment suppresses damage to the electrode body.

[0020] Figure 8 This is a cross-sectional view showing the structure of the sheet member fixed to the outermost periphery of the electrode body according to the modified example 1 of the embodiment.

[0021] Figure 9 This is a cross-sectional view showing the structure in Modified Example 2 of the embodiment, in which the sheet member is fixed to the outermost periphery of the electrode body.

[0022] Figure 10 This is a perspective view showing the structure of the sheet member fixed to the outermost periphery of the electrode body according to the modified example 3 of the embodiment.

[0023] Figure 11 This is a cross-sectional view showing the structure in which the sheet member involved in the modified example 4 of the embodiment is fixed to the outermost periphery of the electrode body.

[0024] Figure 12 This is a cross-sectional view showing the structure in which the sheet member involved in the modified example 5 of the embodiment is fixed to the outermost periphery of the electrode body.

[0025] Figure 13 This is a cross-sectional view showing the structure in which the sheet member involved in the modified example 6 of the embodiment is fixed to the outermost periphery of the electrode body.

[0026] Figure 14 This is a cross-sectional view showing the structure in which the sheet member involved in the modified embodiment 7 is fixed to the outermost periphery of the electrode body.

[0027] Figure 15 This is a top view showing an example of an energy storage device according to variation 8 of the embodiment. Detailed Implementation

[0028] (1) An energy storage element according to one aspect of the present invention has: an electrode body formed by winding an electrode plate; and a sheet member fixed to the outermost periphery of the electrode body, the tensile rigidity of the sheet member being higher than that of the electrode plate.

[0029] According to one embodiment of the present invention, in an energy storage element, the tensile stiffness of the sheet member fixed to the outermost periphery of the electrode body is higher than the tensile stiffness of the electrode plate of the electrode body. Therefore, the sheet member can be used to reinforce the electrode body, thereby suppressing expansion of the electrode body. Consequently, damage to the electrode body can be suppressed.

[0030] (2) In the energy storage element described in (1) above, it may also be configured such that: in the electrode body, a curved portion and a flat portion are formed by winding the electrode plate, and the sheet member is arranged across the boundary portion of the curved portion and the flat portion.

[0031] According to the energy storage element described in (2) above, the boundary portion between the curved and flat portions of the electrode body is arranged by a sheet member, thereby strengthening the boundary portion. When the electrode body expands, the boundary portion between the curved and flat portions of the electrode body is easily damaged; therefore, by strengthening the boundary portion, damage to the boundary portion can be suppressed.

[0032] (3) In the energy storage element described in (2) above, the sheet member may also be configured to cover the entire outermost periphery of the curved portion.

[0033] According to the energy storage element described in (3) above, the outermost circumference of the curved portion of the electrode body is covered by a sheet member, thereby strengthening the curved portion of the electrode body. When the electrode body expands, the curved portion of the electrode body expands, which can easily damage the electrode body. Therefore, by strengthening the curved portion of the electrode body, the expansion of the curved portion can be suppressed.

[0034] (4) In the energy storage element described in (3) above, it can also be configured such that the sheet member covers the entire outermost periphery of the electrode body.

[0035] According to the energy storage element described in (4) above, by covering the entire outermost circumference of the electrode body with a sheet component, the entire circumference of the electrode body can be enhanced, thereby effectively suppressing the expansion of the electrode body.

[0036] (5) In any of the above (1) to (4) energy storage elements, the sheet component may also be formed of fiber-reinforced plastic.

[0037] According to the energy storage element described in (5) above, sheet components with high tensile rigidity can be easily manufactured by forming sheet components from fiber-reinforced plastic.

[0038] Hereinafter, the energy storage element according to embodiments (including variations thereof) of the present invention will be described with reference to the accompanying drawings. The embodiments described below are general or specific examples. The numerical values, shapes, materials, structural elements, arrangement and connection methods of structural elements, manufacturing processes, and sequences of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Dimensions, etc., are not strictly illustrated in the figures. The same reference numerals are used to denote the same or identical structural elements in the figures.

[0039] In the following description and accompanying drawings, the X-axis direction is defined as the arrangement direction of a pair of terminals (positive and negative, the same below) of the energy storage element, the arrangement direction of a pair of current collectors, the direction of the winding axis of the electrode body, or the facing direction of the short side of the container. The Y-axis direction is defined as the facing direction of the long side of the container, the thickness direction (flat direction) of the container or electrode body, or the facing direction of the flat portion of the electrode body. The Z-axis direction is defined as the arrangement direction of the container body and the lid, the arrangement direction of the terminals and the electrode body, the facing direction of the curved portion of the electrode body, or the up-down direction. These X-axis, Y-axis, and Z-axis directions are intersecting (orthogonal in this embodiment). Depending on the usage, the Z-axis direction may not be the up-down direction, but for ease of explanation, the Z-axis direction will be described as the up-down direction below.

[0040] In the following description, 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 referred to simply as the X-axis direction, it means either the positive or negative X-axis direction, or either one of them. The same applies to the Y-axis and Z-axis directions. Expressions indicating parallel or orthogonal relative directions or orientations also include cases where the direction or orientation is not strictly defined. Two directions being parallel (or orthogonal) means not only that the two directions are completely parallel (or orthogonal), but also that they are substantially parallel (or orthogonal), i.e., including, for example, a difference of several percentage points. In the following description, the term "insulating" refers to "electrical insulation." Materials with insulating properties are preferably those with a volume resistivity of 1 × 10⁻⁶. 10 Materials with an Ωm or greater are formed.

[0041] (Implementation Method)

[0042] [1. Overall description of the energy storage element 10]

[0043] First, use Figure 1 and Figure 2 The overall description of the energy storage element 10 in this embodiment will be provided. Figure 1 This is a perspective view showing the appearance of the energy storage element 10 according to this embodiment. Figure 2 This is a perspective view showing the structural elements of the energy storage element 10 according to this embodiment.

[0044] The energy storage element 10 is a rechargeable and dischargeable secondary battery (single cell), more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 10 is used as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorized two-wheelers, watercraft, ships, powered snowmobiles, agricultural machinery, construction machinery, automated guided vehicles (AGVs), or railway vehicles for electric railways. Examples of automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, light oil, liquefied natural gas, etc.) vehicles. Examples of railway vehicles for electric railways include trams, monorails, linear electric locomotives, and hybrid trams with both diesel and electric motors. The energy storage element 10 can also be used as a stationary battery for household or commercial use.

[0045] The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery; it can also be a secondary battery other than a non-aqueous electrolyte secondary battery, or it can be a capacitor. The energy storage element 10 may also be a primary battery, not a secondary battery. The energy storage element 10 may also be a battery using a solid electrolyte. The energy storage element 10 may also be a pouch-type energy storage element. In this embodiment, an energy storage element 10 with a flat rectangular (square) shape in the Y-axis direction is illustrated, but the shape of the energy storage element 10 is not limited to a rectangular shape; it may also be a polygonal prism shape, a long cylindrical shape, an elliptical cylinder shape, or a cylindrical shape, etc., other than a rectangular prism.

[0046] like Figure 1 As shown, the energy storage element 10 has a container 100, a pair of terminals 200 (positive and negative), and a pair of upper washers 400 (positive and negative). Figure 2 As shown, the container 100 contains a pair of lower gaskets 500 (positive and negative electrodes), a pair of current collectors 600 (positive and negative electrodes), an electrode body 700, and a sheet member 800. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but is not shown in the diagram. As for the electrolyte, there are no particular restrictions on its type, as long as it does not impair the performance of the energy storage element 10; various electrolytes can be selected. In addition to the above structural elements, spacers located to the side or below the electrode body 700, and insulating films covering the electrode body 700 and current collectors 600, etc., can also be provided.

[0047] Container 100 is a rectangular (square or box-shaped) shell having a container body 110 with an opening and a lid 120 that closes the opening of the container body 110. Container body 110 is a rectangular cylindrical component with a bottom that constitutes the main body of container 100. Container body 110 has a pair of flat, rectangular long sidewalls 111 on both sides (long sides) in the Y-axis direction, a pair of flat, rectangular short sidewalls 112 on both sides (short sides) in the X-axis direction, and a flat, rectangular bottom wall 113 on the surface (bottom surface) in the negative Z-axis direction.

[0048] The cover 120 is a rectangular plate-shaped member that forms the cover of the container 100 and is elongated in the X-axis direction, and is disposed in the positive Z-axis direction of the container body 110. An injection port 130 and an vent valve 140 are formed on the cover 120. The injection port 130 is the part used to inject electrolyte into the interior of the container 100 during the manufacture of the energy storage element 10, and has an injection port 131 and an injection plug 132. The injection port 131 is a circular through hole formed in the cover 120. The injection plug 132 is a sealing member (cover member) that engages with the cover 120 and closes the injection port 131. The vent valve 140 is a safety valve that releases pressure when the internal pressure of the container 100 rises excessively.

[0049] With this structure, the container 100 forms an internally sealed structure by accommodating the electrode body 700 and the like inside the container body 110 and then joining the container body 110 and the lid 120 by welding or the like. The material of the container 100 (container body 110 and lid 120) is not particularly limited; weldable metals such as stainless steel, aluminum, aluminum alloy, iron, and plated steel sheet can be used, but resin can also be used.

[0050] Terminal 200 is an electrode terminal (positive and negative terminals) electrically connected to electrode body 700 via current collector 600. Terminal 200 is a metal component used to conduct electricity stored in electrode body 700 to the external space of energy storage element 10, and to introduce electricity into the internal space of energy storage element 10 in order to store electricity in electrode body 700. Terminal 200 is formed of a conductive component such as aluminum, aluminum alloy, copper, or copper alloy. Terminal 200 is connected (joined) to current collector 600 by riveting or welding, and is mounted on cover 120.

[0051] Current collectors 600 are disposed on both sides of the electrode body 700 in the X-axis direction and are connected (joined) to the electrode body 700 and the terminal 200. They are current collector components (positive current collector and negative current collector) that electrically connect the electrode body 700 and the terminal 200. Current collectors 600 are connected (joined) to the end 720 of the electrode body 700 (described later) by riveting or welding, and are connected (joined) to the terminal 200 and fixed to the cover 120 by riveting or welding as described above. The material of current collectors 600 is not particularly limited, but the positive current collector 600 is formed of conductive materials such as aluminum or aluminum alloy, similar to the positive current collector foil 701a of the electrode body 700 (described later). The negative current collector 600 is formed of conductive materials such as copper or copper alloy, similar to the negative current collector foil 702a of the electrode body 700 (described later).

[0052] The upper gasket 400 is disposed between the cover 120 of the container 100 and the terminal 200, and the lower gasket 500 is disposed between the cover 120 and the current collector 600. The upper gasket 400 and the lower gasket 500 are formed of insulating resin or the like, but their materials are not particularly limited.

[0053] The electrode body 700 has electrode plates (positive and negative) and spacers, and is an energy storage element (power generation element) formed by winding these electrode plates and spacers. In this embodiment, the electrode body 700 has an elongated cylindrical shape when viewed from the X-axis direction. The electrode body 700 has an electrode body main body 710 and end portions 720 protruding from the electrode body main body 710 in the X-axis direction on both sides. As described above, the end portions 720 are connected (joined) to the current collector 600. A sheet member 800 is disposed on the outermost periphery of the electrode body 700 (electrode body main body 710). The structure of such an electrode body 700 and sheet member 800 will be described in detail below.

[0054] [Description of electrode body 700 and sheet component 800]

[0055] Figure 3 This is a perspective view showing the structure of the electrode body 700 according to this embodiment. Figure 3 (a) shows the structure after a portion of the coiled state of the electrode plates in the electrode body 700 has been unwound. Figure 3 (b) shows the structure of the electrode body 700 after the electrode plate is wound. Figure 4 This is a cross-sectional view showing the structure of the electrode body 700 according to this embodiment. Figure 4 The diagram shows a cut-off surface passing through line IV-IV and parallel to the YZ plane. Figure 3 The cross section of electrode (b) at 700°. Figure 5 This is a perspective view showing the structure of the electrode body 700 and the sheet component 800 involved in this embodiment. Figure 5 (a) shows the state before the sheet component 800 is fixed to the electrode body 700. Figure 5 (b) shows the state after the sheet member 800 is fixed to the electrode body 700. Figure 6 This is a cross-sectional view showing the structure of the electrode body 700 and the sheet member 800 involved in this embodiment. Figure 6 The diagram shows a cut-off surface passing through line VI-VI and parallel to the YZ plane. Figure 5 (b) The cross-section of the electrode body 700 and the sheet component 800. Figure 7 This is a cross-sectional view illustrating how the sheet component 800 of this embodiment suppresses damage to the electrode body 700. Figure 7 (a) and Figure 7 (b) shows a cross section of the state in which the electrode body 700 and the sheet member 800 are housed in the container 100 (container body 110) by cutting with a plane parallel to the YZ plane.

[0056] [2.1 Description of electrode body 700]

[0057] First, the structure of the electrode body 700 will be described in detail. For example... Figure 3 As shown in (a), the electrode body 700 has a positive electrode plate 701, a negative electrode plate 702, and spacers 703 and 704.

[0058] The positive electrode plate 701 is an electrode plate (electrode plate) on the surface of a strip-shaped current collector foil (metal foil) made of aluminum or aluminum alloy, i.e., the positive current collector foil 701a, on which a positive active material layer 701b is formed. The negative electrode plate 702 is an electrode plate (electrode plate) on the surface of a strip-shaped current collector foil (metal foil) made of copper or copper alloy, i.e., the negative current collector foil 702a, on which a negative active material layer 702b is formed. The positive current collector foil 701a and the negative current collector foil 702a can be made of materials stable to the redox reaction during charging and discharging; known materials can be appropriately used, such as nickel, iron, stainless steel, titanium, sintered carbon, conductive polymers, conductive glass, Al-Cd alloys, etc. The positive active material used in the positive active material layer 701b and the negative active material used in the negative active material layer 702b can be either positive or negative active materials capable of absorbing and releasing charge-transferring ions; known materials can be appropriately used.

[0059] Spacers 703 and 704 are microporous sheets made of resin. Known materials can be used as spacers 703 and 704 as long as they do not impair the performance of the energy storage element 10. Spacers 703 and 704 can be made of woven fabrics, nonwoven fabrics, or synthetic resin microporous membranes made of polyolefin resins such as polyethylene, which are insoluble in organic solvents.

[0060] The electrode body 700 is formed by alternately stacking and winding positive electrode plates 701 and negative electrode plates 702 with spacers 703 and 704. That is, the electrode body 700 is formed by stacking and winding positive electrode plates 701, spacers 703, negative electrode plates 702, and spacers 704 in that order. In this embodiment, the electrode body 700 is a flat, wound electrode body formed by winding these positive electrode plates 701 and negative electrode plates 702, etc., around a winding axis L extending parallel to the cover body 120 (in the X-axis direction). The winding axis L is a virtual axis that serves as the central axis when winding the positive electrode plates 701 and negative electrode plates 702, etc. In this embodiment, the winding axis L is a straight line passing through the center of the electrode body 700 and parallel to the X-axis direction.

[0061] Specifically, in the electrode body 700, the positive electrode plate 701 and the negative electrode plate 702 are wound alternately in the direction of extension of the winding axis L (X-axis direction, hereinafter also referred to as the winding axis direction) with spacers 703 and 704 between them. Furthermore, at their respective offset ends, the positive electrode plate 701 and the negative electrode plate 702 have portions where the positive electrode active material layer 701b and the negative electrode active material layer 702b are not formed (coated), exposing the positive electrode current collector foil 701a and the negative electrode current collector foil 702a (non-formed active material layer portions). Thus, as... Figure 3 As shown in (b), the electrode body 700 has a positive electrode end 720 at one end in the winding axis direction (the end in the negative X-axis direction), which is formed by stacking and binding the non-formed portion of the active material layer of the positive electrode plate 701. The electrode body 700 has a negative electrode end 720 at the other end in the winding axis direction (the end in the positive X-axis direction), which is formed by stacking and binding the non-formed portion of the active material layer of the negative electrode plate 702.

[0062] That is, the electrode body 700 has: an electrode body main body portion 710 constituting the main body of the electrode body 700; and a pair of (positive and negative) end portions 720 protruding from the X-axis end portion of the electrode body main body portion 710 in a uniaxial direction. The electrode body main body portion 710 is an elongated cylindrical portion (active material layer forming portion) formed by winding the portion of the positive electrode plate 701 and the negative electrode plate 702 where the positive electrode active material layer 701b and the negative electrode active material layer 702b are formed (coated) with spacers 703 and 704. Thus, the electrode body main body portion 710 has a pair of electrode body curved portions 711 on both sides in the Z-axis direction and a pair of electrode body flat portions 712 on both sides in the Y-axis direction. That is, the electrode body 700 (electrode body main body 710) has a flat shape, which has a pair of curved electrode body curved portions 711 and a pair of flat electrode body flat portions 712. The electrode body 700 is formed by winding a positive electrode plate 701, a negative electrode plate 702, and spacers 703 and 704 around a winding shaft L.

[0063] like Figure 3 (b) and Figure 4 As shown, the electrode body bending portion 711 is a curved portion (bending portion) that bends into a semi-circular arc shape when viewed from the X-axis direction, protruding towards the Z-axis direction, and extends along the X-axis direction. A pair of electrode body bending portions 711 are arranged facing the lid 120 of the container 100 and the bottom wall portion 113 of the container body 110. That is, a pair of electrode body bending portions 711 are portions that bend towards both sides of the lid 120 and the bottom wall portion 113 in the Z-axis direction when viewed from the X-axis direction. The electrode body flat portion 712 is a flat, rectangular portion (flat portion) that connects the ends of the pair of electrode body bending portions 711 and extends towards the Y-axis direction parallel to the XZ plane. A pair of electrode body flat portions 712 are arranged in the Y-axis direction, facing the long sidewall portions 111 on both sides of the container body 110. Furthermore, the bending shape of the electrode body bending portion 711 is not limited to a semi-circular arc shape, but can also be part of an ellipse, etc., and can be bent arbitrarily. The electrode body flat portion 712 is not limited to having a flat outer surface facing the Y-axis direction; this outer surface can be slightly concave or slightly convex.

[0064] Thus, the electrode body 700 is formed by winding the electrode plates (positive electrode plate 701 and negative electrode plate 702). Within the electrode body 700, a bent portion 711 and a flat portion 712 are formed by winding the electrode plates (positive electrode plate 701 and negative electrode plate 702). In this structure, as... Figure 4 As shown, the boundary portion between the bent portion 711 and the flat portion 712 of the electrode body is referred to as the boundary portion 713. The boundary portion 713 is the boundary (connection portion) formed between the bent portion 711 and the flat portion 712 of the electrode body body 710, and extends along the X-axis direction. Four boundary portions 713 are formed on the electrode body 700 (electrode body body 710).

[0065] [2.2 Description of sheet component 800]

[0066] Next, the structure of sheet component 800 will be described in detail. For example... Figure 5 As shown in (a), the sheet component 800 is a sheet-like component separate from the electrode body 700, such as Figure 5 As shown in (b), the sheet component 800 is disposed on the outermost periphery of the electrode body 700.

[0067] In this embodiment, the sheet member 800 has the same length as the electrode body main body 710 in the X-axis direction and is disposed on the outermost periphery of the electrode body main body 710. The outermost periphery of the electrode body 700 (electrode body main body 710) refers to the last one-turn portion (the outermost portion) after the positive electrode plate 701, negative electrode plate 702, spacers 703, and 704 are wound. The sheet member 800 is disposed on the outer peripheral surface of this last one-turn portion (the outermost portion) of the electrode body 700 (electrode body main body 710). The sheet member 800 may be formed to be slightly shorter than the electrode body main body 710 in the X-axis direction, and may also be formed to be longer than the electrode body main body 710 (or may protrude to the end 720) as long as it does not hinder the engagement of the current collector 600 and the end 720.

[0068] like Figure 6 As shown, the sheet member 800 has a pair of sheet bends 810 and a pair of sheet flats 820. The sheet bends 810 are sheet-like portions disposed on the outermost periphery (outer peripheral surface) of the electrode body bends 711. In this embodiment, the sheet bends 810 are configured to cover the entire outermost periphery (outer peripheral surface) of the electrode body bends 711. Thus, the pair of sheet bends 810 clamp the pair of electrode body bends 711 in the Z-axis direction and cover the entire outermost periphery (outer peripheral surface) of the pair of electrode body bends 711. The sheet flats 820 are sheet-like portions disposed on the outermost periphery (outer peripheral surface) of the electrode body flats 712. In this embodiment, the sheet flats 820 are configured to cover the entire outermost periphery (outer peripheral surface) of the electrode body flats 712. Thus, a pair of sheet flat portions 820 clamp and arrange a pair of electrode body flat portions 712 in the Y-axis direction, and cover the entire outermost periphery (outer peripheral surface) of the pair of electrode body flat portions 712. In this way, the sheet member 800 covers the entire outermost periphery (outer peripheral surface) of the electrode body main body portion 710.

[0069] In this embodiment, the flat portion 820 of the sheet in the positive Y-axis direction has a first end portion 821 and a second end portion 822 of the sheet member. The first end portion 821 and the second end portion 822 of the sheet member are portions of the flat portion 820 that are located near the bent portion 711 of the electrode body (in this embodiment, the end portion in the positive Z-axis direction) and extend along the X-axis. The first end portion 821 and the second end portion 822 of the sheet member are the ends of the sheet member 800 (see reference). Figure 5The sheet member 800 is wound around the outermost periphery (outer peripheral surface) of the electrode body 700 (electrode body main body 710) with the first end 821 and the second end 822 of the sheet member as the starting and ending points, respectively. In this embodiment, the first end 821 and the second end 822 of the sheet member are arranged facing each other (the tips are in contact with each other) in the Z-axis direction in a manner that does not overlap in the Y-axis direction (thickness direction).

[0070] The first end 821 and the second end 822 of the sheet member may or may not be connected (joined) to each other in the Z-axis direction. When the first end 821 and the second end 822 of the sheet member are connected (joined) to each other in the Z-axis direction, an adhesive layer, such as an adhesive layer, may be provided on at least one surface of the surfaces of the first end 821 and the second end 822 facing each other in the Z-axis direction for connection (joining). Alternatively, a recess may be provided on one surface and a protrusion on the other surface of the surfaces of the first end 821 and the second end 822 facing each other in the Z-axis direction, and the first end 821 and the second end 822 of the sheet member may be connected (joined) by mechanical engagement such as snap-fit ​​or press-fit. In this way, the first end 821 and the second end 822 of the sheet member do not overlap in the Y-axis direction (thickness direction), thus preventing gaps from easily forming between the sheet member 800 and the electrode body 700 (electrode body main body 710).

[0071] Thus, the sheet member 800 covers the entire outermost circumference of the electrode body 700 (electrode body main body 710). Consequently, the sheet member 800 is positioned across the boundary portion 713 between the electrode body curved portion 711 and the electrode body flat portion 712. That is, the sheet member 800 is continuously positioned on the outer peripheral surfaces of the electrode body curved portion 711 and the electrode body flat portion 712 from one side of the boundary portion 713 to the other side of the boundary portion 713. In other words, in the sheet member 800, the portion of the sheet curved portion 810 near the sheet flat portion 820 and the portion of the sheet flat portion 820 near the sheet curved portion 810 are continuously and integrally formed. The sheet member 800 covers the entire outermost circumference of the electrode body curved portion 711. That is, the sheet member 800 is continuously positioned on the outer surface of the electrode body curved portion 711 from one end to the other end. In other words, the sheet member 800 is integrally formed continuously from one end of the sheet bending portion 810 to the other end.

[0072] The sheet member 800 is fixed to the outermost periphery of the electrode body 700 (electrode body main body 710). In this embodiment, the sheet member 800 has an adhesive layer or similar bonding layer on the inner surfaces of its first end 821 and second end 822, and the first end 821 and second end 822 are bonded to the outermost periphery of the electrode body 700 by adhesive bonding or similar bonding methods. The sheet member 800 can have an adhesive layer or similar bonding layer at any position, and can be bonded and fixed to the outermost periphery of the electrode body 700 at any position. Alternatively, the sheet member 800 can have an adhesive layer or similar bonding layer on its entire inner surface, and the entire inner surface of the sheet member 800 can be bonded and fixed to the outermost periphery of the electrode body 700. The fixing of the sheet member 800 to the electrode body 700 can be based on bonding with an adhesive or similar method, or on welding or similar methods.

[0073] The tensile stiffness of the sheet component 800 is higher than that of the electrode plates in the electrode body 700. Tensile stiffness is an indicator of the ease with which an object deforms under axial tensile force, and can also be called axial stiffness. The tensile stiffness is measured according to JIS Z 2241:2001, and the tensile stiffness of the two components is compared. That is, the sheet component 800 stretches less within the elastic deformation than the electrode plate. The sheet component 800 is more difficult to stretch than the electrode plate when subjected to the same tensile force as the electrode plate. The tensile stiffness of the sheet component 800 is higher than that of at least one of the positive electrode plate 701 and the negative electrode plate 702. Preferably, the tensile stiffness of the sheet component 800 is higher than that of the electrode plate located on the outermost side of the positive electrode plate 701 and the negative electrode plate 702 (in this embodiment, the negative electrode plate 702). In this embodiment, the tensile stiffness of the sheet component 800 is higher than that of both the positive electrode plate 701 and the negative electrode plate 702.

[0074] The sheet member 800 is a thin, high-strength, and flexible sheet member containing reinforcing fibers such as carbon fiber, glass fiber, or aramid fiber. In this embodiment, the sheet member 800 is formed of fiber-reinforced plastic (FRP). The thickness of the sheet member 800 is preferably 50 μm or more and 200 μm or less, more preferably 70 μm or more and 150 μm or less, and even more preferably 90 μm or more and 110 μm or less. Therefore, when the sheet member 800 is wound along the outermost periphery (outer peripheral surface) of the electrode body 700 (particularly the bent portion 711 of the electrode body), the formation of a gap between the sheet member 800 and the outermost periphery (outer peripheral surface) can be suppressed. The sheet member 800 is not limited to the above-mentioned materials; it can be formed from a hard (high tensile rigidity) resin, or it can be formed by insulating a metal plate (metal foil), etc.

[0075] In the electrode body 700 and sheet member 800 with such a structure, as described below, the sheet member 800 suppresses damage to the electrode body 700. First, as... Figure 7 As shown in (a), when the electrode body 700 expands, an expansion force F1 in the Y-axis direction is generated in the flat portion 712 of the electrode body. Since the flat portion 712 of the electrode body is held by a pair of long sidewall portions 111 of the container 100 (container body 110), the gap between the flat portion 712 of the electrode body in the Y-axis direction gradually decreases due to the expansion.

[0076] Then, as Figure 7 As shown in (b), in the flat portion 712 of the electrode body, due to the decrease in the gap in the Y-axis direction, expansion occurs in the Z-axis direction, generating an expansion force F2 in the Z-axis direction. The bent portion 711 of the electrode body also expands. Therefore, when the sheet member 800 is not fixed to the outermost periphery of the electrode body 700, stress concentrates in and around the bent portion 711 of the electrode body, particularly at the boundary portion 713 between the bent portion 711 and the flat portion 712, potentially causing damage to the electrode body 700. In contrast, in this embodiment, the sheet member 800, with a tensile stiffness higher than that of the electrode plate of the electrode body 700, is fixed to the outermost periphery of the electrode body 700. Therefore, in the electrode body 700, the expansion force from the inside can be suppressed by the compressive force from the outside of the sheet member 800. This suppresses the rate of increase in strain generated in the electrode plate, thus extending the time until the electrode plate breaks. Therefore, damage to the electrode body 700 can be suppressed, and a longer lifespan for the energy storage element 10 can be achieved. Here, regarding the container 100 housing the electrode body 700, a comparison is made between the case where the wall of the container 100 is membrane-like and the case where it is flat. When the wall of the container 100 is membrane-like, the wall of the container 100 deforms (expands) when the electrode body 700 expands, so the gap in the Y-axis direction of the flat portion 712 of the electrode body is not easily reduced. That is, the expansion force F2 in the Z-axis direction of the electrode body 700 is relatively small. On the other hand, when the wall of the container 100 is flat, even if the electrode body 700 expands, the wall of the container 100 is not easily deformed (expanded), so the gap in the Y-axis direction of the flat portion 712 of the electrode body is easily reduced. That is, the expansion force F2 in the Z-axis direction of the electrode body 700 is relatively large. Therefore, when the wall of the container 100 is flat, the lifespan of the energy storage element 10 is more significantly extended.

[0077] [3. Explanation of the effects]

[0078] As described above, in the energy storage element 10 according to an embodiment of the present invention, the tensile stiffness of the sheet member 800 fixed to the outermost periphery of the electrode body 700 is higher than the tensile stiffness of the electrode plates (positive electrode plate 701, negative electrode plate 702) of the electrode body 700. Therefore, the sheet member 800 can be used to reinforce the electrode body 700, thereby suppressing the expansion of the electrode body 700. Consequently, damage to the electrode body 700 can be suppressed.

[0079] By arranging the sheet member 800 across the boundary portion 713 of the electrode body 700 between the bent portion 711 and the flat portion 712, the boundary portion 713 can be reinforced. When the electrode body 700 expands, the boundary portion 713 between the bent portion 711 and the flat portion 712 is easily damaged; therefore, by reinforcing the boundary portion 713, damage to the boundary portion 713 can be suppressed.

[0080] By covering the entire outermost circumference of the electrode body bending portion 711 of the electrode body 700 with the sheet member 800, the electrode body bending portion 711 can be strengthened. When the electrode body 700 expands, the electrode body 700 is easily damaged due to the expansion of the electrode body bending portion 711. Therefore, by strengthening the electrode body bending portion 711, the expansion of the electrode body bending portion 711 can be suppressed.

[0081] By covering the entire outermost circumference of the electrode body 700 with the sheet component 800, the entire circumference of the electrode body 700 can be enhanced, thus effectively suppressing the expansion of the electrode body 700.

[0082] By forming sheet components 800 with fiber-reinforced plastic, sheet components 800 with high tensile stiffness can be easily manufactured.

[0083] [Explanation of 4 variations]

[0084] The energy storage element 10 according to the embodiments of the present invention has been described above, but the present invention is not limited to the above embodiments. The embodiments disclosed herein are illustrative in all respects, and the scope of the present invention includes all modifications within the same meaning and scope as the claims.

[0085] (Variations 1 and 2)

[0086] In the above embodiment, the sheet member 800 is bonded to the outermost periphery of the electrode body 700 by adhesive or the like, and is thus fixed to the outermost periphery of the electrode body 700, but is not limited to this and can be done in various ways. Figure 8 This is a cross-sectional view showing the structure of the sheet member 800 fixed to the outermost periphery of the electrode body 700 in Modified Example 1 of this embodiment. Figure 9 This is a cross-sectional view showing the structure of the sheet member 800 fixed to the outermost periphery of the electrode body 700 in Modified Example 2 of this embodiment. Figure 8 and Figure 9 It corresponds to Figure 6 (b) is the diagram.

[0087] like Figure 8 As shown, in Modification 1, the sheet member 800 is connected to its first end 821 and second end 822 using a connecting member 830. The connecting member 830 is an adhesive tape (adhesive sheet, adhesive film) with an adhesive layer on its inner surface, or a tape (sheet, film) coated with adhesive on its inner surface, which is then adhered and fixed to the first end 821 and second end 822 of the sheet member. The connecting member 830 can also be fixed to the first end 821 and second end 822 of the sheet member using heat fusion or the like. Thus, the sheet member 800 is fixed to the outermost periphery of the electrode body 700. Other structures in this modification are the same as in the above embodiment, and therefore detailed descriptions are omitted.

[0088] like Figure 9 As shown, in Modification 2, the sheet member 800 is fixed to the outermost periphery of the electrode body 700 by being clamped by the electrode body flat portion 712 of the electrode body 700 and the long side wall portion 111 of the container 100 (container body 110). Other structures in this modification are the same as in the above-described embodiment, therefore detailed descriptions are omitted.

[0089] According to modifications 1 and 2, the same effects as the above-described embodiments can be achieved. In particular, in modifications 1 and 2, since it is not necessary to directly attach the sheet member 800 to the electrode body 700, the sheet member 800 can be easily fixed to the electrode body 700. Even if it is necessary to remove the sheet member 800 from the electrode body 700, damage to the electrode body 700 can be suppressed.

[0090] In Modification 1, the electrode body 700 and the sheet member 800 can be fixed using the connecting member 830. In Modification 1, in addition to fixing using the connecting member 830, the sheet member 800 can also be directly glued to the electrode body 700 in the same way as in the above embodiment.

[0091] (Variation Example 3)

[0092] In the above embodiment, a sheet member 800 covers almost the entire outermost periphery (outer peripheral surface) of the electrode body main body 710 in the winding axis direction (X-axis direction) of the electrode body 700, but is not limited thereto. The sheet member 800 may also cover only a portion of the outermost periphery of the electrode body main body 710 in the winding axis direction, or a plurality of sheet members 800 may be configured. Figure 10 This is a perspective view showing the structure of the sheet member 801 fixed to the outermost periphery of the electrode body 700 in Modified Example 3 of this embodiment.

[0093] like Figure 10 As shown, in Modification 3, three sheet members 801 arranged at intervals in the X-axis direction are fixed on the outermost periphery (outer peripheral surface) of the electrode body 700 (electrode body main body 710). That is, in Modification 3, not one but a plurality of sheet members 801 are arranged, and these plurality of sheet members 801 do not cover the entire outermost periphery (outer peripheral surface) of the electrode body main body 710 in the winding axis direction (X-axis direction) of the electrode body 700. Other structures of this modification are the same as those in the above embodiment, and therefore detailed descriptions are omitted.

[0094] According to Modification 3, the same effects as the above-described embodiments can be achieved. In particular, in Modification 3, since a plurality of sheet members 801 can be fixed to the electrode body 700, it is easy to fix the sheet members 801 to the electrode body 700. Since a structure is not used in which a plurality of sheet members 801 cover the entire outermost periphery of the electrode body main body 710 in the X-axis direction, it is not necessary to position the plurality of sheet members 801 with high precision. The tensile stiffness of each of the plurality of sheet members 801 can be set according to the tensile stiffness of the electrode body 700 portion corresponding to each sheet member 801. That is, the design freedom of the sheet members 801 is increased.

[0095] In variation 3, a structure can also be adopted in which any two or any one of the three sheet members 801 are fixed to the electrode body 700. There is no particular limitation on the number of sheet members 801 or the width of the sheet members 801 in the X-axis direction.

[0096] (Variations 4-7)

[0097] In the above embodiment, the sheet member 800 covers the entire outermost periphery of the electrode body 700, but is not limited thereto. The sheet member 800 only needs to cover at least a portion of the outermost periphery of the electrode body 700. Figure 11 This is a cross-sectional view showing the structure of the sheet member 802 fixed to the outermost periphery of the electrode body 700 in Modification 4 of this embodiment. Figure 12 This is a cross-sectional view showing the structure of the sheet member 803 fixed to the outermost periphery of the electrode body 700 in Modified Example 5 of this embodiment. Figure 13 This is a cross-sectional view showing the structure of the sheet member 804 fixed to the outermost periphery of the electrode body 700 in Modification 6 of this embodiment. Figure 14 This is a cross-sectional view showing the structure of the sheet member 805 fixed to the outermost periphery of the electrode body 700 according to the modified example 7 of this embodiment. Figures 11-14 Is with Figure 6 The diagram in (a) shows the part corresponding to the positive Z-axis direction of the electrode body 700 and the sheet component 800.

[0098] like Figure 11 As shown, in Modification 4, the sheet member 802 has a sheet bending portion 810 in the positive Z-axis direction and a pair of sheet flat portions 823. The pair of sheet flat portions 823 are located at the Z-axis positive direction ends of the pair of sheet flat portions 820 in the above embodiment. Thus, the sheet member 802 covers the outermost periphery of the Z-axis positive direction ends of the electrode body bending portion 711 and the pair of electrode body flat portions 712 in the positive Z-axis direction of the electrode body 700 (electrode body main body portion 710), and is fixed to the outermost periphery by adhesive or the like. That is, the sheet member 802 covers the entire circumference of the outermost periphery of the electrode body bending portion 711 and is arranged across the boundary portion 713 between the electrode body bending portion 711 and the electrode body flat portion 712. Other structures of this modification are the same as those in the above embodiment, so detailed descriptions are omitted.

[0099] In variation 4, the length of the flat portion 823 of the sheet material in the Z-axis direction is not particularly limited. In addition to the portion in the positive Z-axis direction, or the portion that replaces the portion in the positive Z-axis direction, the sheet material member 802 may also have a portion in the negative Z-axis direction with the same structure as the portion in the positive Z-axis direction.

[0100] like Figure 12 As shown, in Modification 5, the sheet member 803 has a pair of bent sheet portions 811 and a pair of flat sheet portions 824. The pair of bent sheet portions 811 are located at the two ends of the bent sheet portions 810 in the positive Z-axis direction in the above embodiment. The pair of flat sheet portions 824 are located at the ends of the flat sheet portions 820 in the positive Z-axis direction in the above embodiment. Thus, the sheet member 803 covers the two ends of the bent electrode portion 711 in the positive Z-axis direction and the ends of the flat electrode portions 712 in the positive Z-axis direction in the electrode body 700 (electrode body main body 710) at the two ends of the bent electrode portion 711 in the positive Z-axis direction and the outermost periphery of the flat electrode portion 712 in the positive Z-axis direction, and is fixed to the outermost periphery by adhesive or other bonding. That is, the sheet member 803 is arranged to cross the boundary portion 713 of the bent electrode portion 711 and the flat electrode portion 712. Other structures of this modification are the same as those in the above embodiment, so detailed descriptions are omitted.

[0101] In variation 5, the length of the flat portion 824 in the Z-axis direction is not particularly limited. The sheet member 803 may also have only a bent portion 811 and a flat portion 824 in the positive Y-axis direction, or a bent portion 811 and a flat portion 824 in the negative Y-axis direction. In addition to the aforementioned portions in the positive Z-axis direction, or in place of the portions in the positive Z-axis direction, the sheet member 803 may also have portions in the negative Z-axis direction with the same structure as the portions in the positive Z-axis direction.

[0102] like Figure 13As shown, in Modification 6, the sheet member 804 has a sheet bending portion 812. The sheet bending portion 812 is located at the center (excluding the end) of the sheet bending portion 810 in the positive Z-axis direction in the above embodiment. Thus, the sheet member 804 covers the outermost periphery of the center (excluding the end) of the electrode body bending portion 711 in the positive Z-axis direction of the electrode body 700 (electrode body main body 710), and is fixed to this outermost periphery by adhesive bonding or the like. Other structures in this modification are the same as in the above embodiment, and therefore detailed descriptions are omitted.

[0103] In variation 6, the length of the sheet bending portion 812 in the Y-axis direction is not particularly limited. In addition to the portions in the positive Z-axis direction described above, or in place of the portions in the positive Z-axis direction, the sheet member 804 may also have portions in the negative Z-axis direction with the same structure as the portions in the positive Z-axis direction.

[0104] like Figure 14 As shown, in Modification 7, the sheet member 805 has a pair of flat sheet portions 825. These flat sheet portions 825 are located at the center (excluding the ends) of the pair of flat sheet portions 820 in the Z-axis direction in the above embodiment. Thus, the sheet member 805 covers the outermost periphery of the center (excluding the ends) of the pair of flat electrode portions 712 in the Z-axis direction of the electrode body 700 (electrode body main body 710), and is fixed to this outermost periphery by adhesive bonding or the like. Other structures in this modification are the same as in the above embodiment, and therefore detailed descriptions are omitted.

[0105] In variation 7, the length of the flat portion 825 in the Z-axis direction is not particularly limited. The sheet member 805 may also have only a flat portion 825 in the positive Y-axis direction or a flat portion 825 in the negative Y-axis direction.

[0106] According to modifications 4 to 7, since the portion of the electrode body 700 to which the sheet member is fixed can be strengthened, damage to the electrode body 700 can be suppressed. During manufacturing, sometimes the sheet member is fixed to the electrode body 700 while it is being held in place by a jig. In this case, it is impossible to fix the sheet member to the jig-held portion of the electrode body 700. Thus, in modifications 4 to 7, the sheet member can be selectively fixed to the desired reinforced portion or the portion of the electrode body 700 where the sheet member can be fixed. That is, the electrode body 700 can be effectively strengthened.

[0107] (Variation Example 8)

[0108] The energy storage element 10 can be used in an energy storage device. In this case, it is sufficient to apply the technology of the present invention to at least one energy storage element 10 of the energy storage device. Figure 15This is a top view showing an example of the energy storage device 12 according to Variation 8 of this embodiment. Figure 15 As shown, a plurality of energy storage units 11 are arranged inside the energy storage device 12. Each energy storage unit 11 is composed of a plurality of electrically connected energy storage elements 10. The energy storage device 12 may also have a busbar (not shown) electrically connecting the plurality of energy storage elements 10 and a busbar (not shown) electrically connecting the plurality of energy storage units 11, etc. The energy storage unit 11 or the energy storage device 12 may also have a status monitoring device (not shown) for monitoring the status of one or more energy storage elements 10. The energy storage device 12 may also have only one energy storage unit 11 (i.e., the energy storage unit 11 may also be referred to as the energy storage device).

[0109] (Other variations)

[0110] In the above embodiment, the tensile rigidity of the sheet component 800 is higher than that of both the positive electrode plate 701 and the negative electrode plate 702, but it only needs to be higher than the tensile rigidity of either the positive electrode plate 701 or the negative electrode plate 702. That is, the tensile rigidity of the sheet component 800 can also be lower than that of either the positive electrode plate 701 or the negative electrode plate 702.

[0111] In the above embodiment, a single sheet (layer) component 800 is fixed on the electrode body 700, but multiple sheets (layers) of sheet components 800 may also be fixed. In this case, the tensile stiffness of the multiple sheets (layers) of sheet components 800 should be higher than the tensile stiffness of the electrode plate of the electrode body 700.

[0112] In the above embodiments, the first end 821 and the second end 822 of the sheet member 800 are disposed at the positive Z-axis end of the flat portion 820 in the positive Y-axis direction, but they can also be disposed at any position on the sheet member 800. The first end 821 and the second end 822 can also be disposed at the negative Z-axis end or the center of the flat portion 820 in the positive Y-axis direction. The first end 821 and the second end 822 can be disposed on the flat portion 820 in the negative Y-axis direction, or on the bent portion 810 in the positive or negative Z-axis direction.

[0113] In the above embodiment, the first end 821 and the second end 822 of the sheet member are arranged in contact with each other at their tips in a manner that does not overlap in the thickness direction, but this is not a limitation. The first end 821 and the second end 822 of the sheet member may also be arranged with their tips separated from each other. The first end 821 and the second end 822 of the sheet member may also be arranged overlapping in the thickness direction. In this case, the overlapping portions of the first end 821 and the second end 822 of the sheet member may also be connected (joined) to the electrode body 700 by bonding (adhesion, etc.), welding, or by interlocking or pressing based on a textured structure.

[0114] In the above embodiment, the first end 821 and the second end 822 of the sheet member 800 are provided at the Z-axis positive direction end of the flat portion 820 of the sheet in the positive Y-axis direction, but the first end 821 and the second end 822 of the sheet member may not be provided. That is, the sheet member 800 may also have a seamless structure. Specifically, the sheet member 800 may also be composed of an integrally formed member manufactured by resin molding or the like. In this case, the sheet member 800 is fixed to the electrode body 700 by inserting the electrode body 700 through the opening in the X-axis direction of the sheet member 800. When the sheet member 800 has a seamless structure and is formed of fiber-reinforced plastic, the fibers of the fiber-reinforced plastic are oriented along the outermost periphery (outer peripheral surface) of the electrode body 700. Thus, the tensile rigidity of the sheet member 800 can be designed according to the shape of the electrode body 700.

[0115] In the above embodiment, the electrode body 700 is a wound electrode body with the winding shaft L parallel to the cover body 120. However, the electrode body 700 may also be a wound electrode body with the winding shaft L perpendicular to the cover body 120. In the electrode body 700, the end portion 720 is not limited to a portion that protrudes entirely from the end of the electrode body main body portion 710, but may also be a tab portion (a portion formed by stacking a plurality of tabs of electrode plates) that protrudes from a part of the end of the electrode body main body portion 710.

[0116] Any combination of the structural elements contained in the above embodiments and their variations is also included within the scope of this invention.

[0117] Industrial availability

[0118] This invention can be applied to energy storage components such as lithium-ion secondary batteries.

[0119] Explanation of reference numerals in the attached figures

[0120] 10 energy storage components

[0121] 11 energy storage units

[0122] 12 energy storage devices

[0123] 100 containers

[0124] 110 Container Body

[0125] 111 Long sidewall section

[0126] 120 cover

[0127] 200 terminals

[0128] 600 collector

[0129] 700 electrode body

[0130] 701 Positive Plate

[0131] 701a Positive Current Collector Foil

[0132] 701b positive electrode active material layer

[0133] 702 negative electrode plate

[0134] 702a negative electrode current collector foil

[0135] 702b negative electrode active material layer

[0136] 703 and 704 spacers

[0137] 710 Electrode Body Main Body

[0138] 711 Electrode Body Bending Section

[0139] 712 Electrode Body Flat Section

[0140] 713 boundary section

[0141] 720 end

[0142] Sheet components of types 800, 801, 802, 803, 804, and 805

[0143] 810, 811, and 812 sheet bending sections

[0144] Flat section of 820, 823, 824, and 825 sheets

[0145] 821 sheet component first end

[0146] 822 sheet component second end

[0147] 830 connecting components

Claims

1. An energy storage element, wherein, have: Electrode bodies are formed by winding electrode plates; and The sheet component is fixed to the outermost periphery of the electrode body. The tensile stiffness of the sheet component is higher than that of the electrode plate.

2. The energy storage element according to claim 1, wherein, In the electrode body, curved portions and flat portions are formed by winding the electrode plate. The sheet member is positioned across the boundary between the curved portion and the flat portion.

3. The energy storage element according to claim 2, wherein, The sheet member covers the entire outermost circumference of the curved portion.

4. The energy storage element according to claim 3, wherein, The sheet component covers the entire outermost circumference of the electrode body.

5. The energy storage element according to any one of claims 1 to 4, wherein, The sheet component is formed of fiber-reinforced plastic.

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