WO2022163616A1

WO2022163616A1 - Electricity storage element and electricity storage device

Info

Publication number: WO2022163616A1
Application number: PCT/JP2022/002562
Authority: WO
Inventors: 一弥岡部; 良一奥山
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2021-01-29
Filing date: 2022-01-25
Publication date: 2022-08-04
Also published as: JPWO2022163616A1

Abstract

An electricity storage element (100) which is provided with an electrode body (130) that is obtained by winding an electrode plate, on which a mixture layer is formed, around a winding axis (R) that extends in a first direction. The electrode plate has: a mixture layer formation part (131) on which the mixture layer is formed; and a mixture layer non-formation part (132) which is arranged on a position closer to an end than the mixture layer formation part (131) in the first direction, and on which the mixture layer is not formed. The electrode body (130) has a flattened shape wherein the length in a second direction that intersects with the first direction is longer than the length in a third direction that intersects with the first direction and the second direction. In the first direction, the width of the mixture layer formation part (131) (the mixture layer formation part width (C1)) is not less than 16 times the width of the mixture layer non-formation part (132 or 133) (the mixture layer non-formation part width (C2 or C3)).

Description

Storage element and storage device

The present invention relates to an electric storage element including an electrode body around which electrode plates are wound, and an electric storage device including an electric storage element.

Conventionally, a power storage element is widely known that includes a flat-shaped electrode body in which an electrode plate on which a composite material layer is formed is wound. Patent Literature 1 discloses a non-aqueous electrolyte secondary battery (power storage element) that includes a flat electrode body in which a strip-shaped electrode plate having an electrode active material layer formed on the surface is wound.

JP 2013-98026 A

In a power storage element, when an electrode body is formed by winding an electrode plate around a winding axis, an electrode body in which the winding axis extends in the vertical direction (vertical direction) (hereinafter also referred to as a horizontally wound electrode body) There is an electrode body (hereinafter also referred to as a vertically wound electrode body) in which the rotation axis extends in the left-right direction (horizontal direction). In general, from the viewpoint of space efficiency in a container, energy density is higher in a storage element with horizontally wound electrode bodies than in a storage element with vertically wound electrode bodies. Since the electric storage element having the above-described conventional configuration generally includes the vertically wound electrode assembly, there is a possibility that the energy density may be low. For this reason, it is desirable to have a structure capable of improving the energy density even in an electric storage element having a vertically wound electrode body.

An object of the present invention is to provide a power storage element and a power storage device capable of improving energy density.

A power storage element according to an aspect of the present invention is a power storage element including an electrode body in which an electrode plate having a composite material layer formed thereon is wound around a winding axis extending in a first direction, wherein the electrode plate comprises: A mixture layer forming portion having the mixture layer formed thereon, and a mixture layer non-forming portion disposed at an end portion in the first direction from the mixture layer forming portion and having no mixture layer formed thereon. , wherein the electrode body has a flat shape in which a length in a second direction that intersects the first direction is longer than a length in a third direction that intersects the first direction and the second direction. In the first direction, the width of the composite material layer forming portion is 16 times or more the width of the composite material layer non-forming portion.

A power storage element according to an aspect of the present invention is a power storage element including an electrode body in which an electrode plate having a composite material layer formed thereon is wound around a winding axis extending in a first direction, wherein the electrode plate comprises: A mixture layer forming portion having the mixture layer formed thereon, and a mixture layer non-forming portion disposed at an end portion in the first direction from the mixture layer forming portion and having no mixture layer formed thereon. , wherein the electrode body has a flat shape in which a length in a second direction that intersects the first direction is longer than a length in a third direction that intersects the first direction and the second direction. A first length in the first direction of the electrode body may be five times or more of a second length in the second direction of the electrode body.

A power storage device according to an aspect of the present invention includes any one of the plurality of power storage elements described above and a pair of external terminals. The first storage element has a pair of first electrode terminals aligned in the first direction, and the second storage element has a pair of second electrode terminals aligned in the first direction. wherein the pair of external terminals includes a first electrode terminal of the pair of first electrode terminals that is closer to the second storage element and a pair of second electrode terminals that is closer to the first storage element and a second electrode terminal.

The present invention can be realized not only as such a power storage element and power storage device, but also as an electrode body.

According to the electric storage device and the like of the present invention, it is possible to improve the energy density.

FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. FIG. 2 is a perspective view showing the external appearance of a power storage element according to the embodiment and an electrode body included in the power storage element. FIG. 3 is a front view showing the size of the electrode body according to the embodiment. FIG. 4 is a front view showing the configuration of a laterally-wound electrode body as a comparison target with the vertically-wound electrode body according to the embodiment. FIG. 5A is a graph showing a comparison of energy densities between a power storage element using a vertically wound electrode body according to an embodiment and a power storage element using a horizontally wound electrode body in a comparative example and an example. FIG. 5B is a graph showing a comparison of energy densities between the energy storage elements using the vertically wound electrode bodies according to the embodiment and the energy storage elements using the horizontally wound electrode bodies in the comparative example and the working example. FIG. 6 is a front view showing the configuration of an electrode assembly according to Modification 1 of the embodiment. FIG. 7 is a perspective view showing the configuration of a power storage element according to Modification 2 of the embodiment.

According to this, in the electric storage element, the electrode body has a flat shape in which the electrode plate is wound around the winding axis extending in the first direction, the second direction is longer than the third direction, and the electrode body has a flat shape. In the above, the width of the composite material layer forming portion of the electrode plate is 16 times or more the width of the composite material layer non-forming portion of the end portion of the electrode plate in the first direction. In the electric storage element, when the electrode body is elongated in the horizontal direction, the space efficiency in the container is reversed between the horizontally-wound electrode body and the vertically-wound electrode body, and the vertically-wound electrode body is the horizontally-wound electrode body. higher energy density than Specifically, in the horizontally wound electrode body, even if the electrode body is elongated in the horizontal direction, the ratio of the composite material layer forming portion of the electrode plate in the vertical direction in the container is generally constant. The proportion of the mixture layer-forming portion in the container is substantially constant. On the other hand, in the vertically wound electrode body, when the electrode body is elongated in the horizontal direction, the ratio of the composite material layer formed portion to the composite material layer non-formed portion of the electrode plate becomes large. The proportion occupied by the part becomes large. The inventors of the present application have found that when the width of the composite material layer formed portion in the electrode body is 16 times or more the width of the composite material layer non-formed portion, the vertically wound electrode body is superior to the horizontally wound electrode body in the capacity of the storage element. It was found that the energy density increases. Therefore, by setting the width of the composite material layer forming portion in the electrode body to be 16 times or more the width of the composite material layer non-forming portion, the energy density of the electric storage element can be improved.

In the first direction, the width of the composite material layer forming portion may be 40 times or more the width of the composite material layer non-forming portion.

The inventors of the present application have found that the energy density effectively increases until the width of the composite material layer formed portion of the electrode body becomes 40 times or more the width of the composite material layer non-formed portion in the electric storage element. . Therefore, by making the width of the composite material layer formed portion of the electrode body 40 times or more the width of the composite material layer non-formed portion, it is possible to use an electrode body having an effectively high energy density. can improve the energy density of

In the first direction, the width of the composite material layer forming portion may be 80 times or less of the width of the composite material layer non-forming portion.

The inventors of the present application have found that, in an electric storage element, if the width of the composite material layer forming portion of the electrode body is greater than 80 times the width of the composite material layer non-forming portion, the electrode body becomes too long and difficult to form. It was found that the energy density did not increase significantly. Therefore, by setting the width of the composite material layer forming portion of the electrode body to 80 times or less of the width of the composite material layer non-forming portion, it is possible to easily form the electrode body and improve the energy density of the storage element. can.

The first length in the first direction of the electrode body may be twice or more the second length in the second direction of the electrode body.

The inventors of the present application have found that in a storage element, when the first length in the first direction of the electrode body is at least twice the second length in the second direction, the vertically wound electrode body is superior to the horizontally wound electrode body. It was found that the energy density is higher than Therefore, by making the first length in the first direction of the electrode body twice or more the second length in the second direction, the energy density of the electric storage element can be improved.

The first length may be five times or more of the second length.

The inventors of the present application have found that the energy density effectively increases until the first length of the electrode body is five times the second length in the storage device. Therefore, by setting the first length of the electrode body to be 5 times or more the second length, an electrode body with effectively increased energy density can be used, thereby improving the energy density of the storage element. be able to.

According to this, in the electric storage element, as described above, the first length in the first direction of the electrode body is five times or more the second length in the second direction, thereby improving the energy density of the electric storage element. can be planned.

The width of the composite material layer forming portion in the first direction may be 567 mm or more.

The inventors of the present application have found that the energy density is effectively increased when the width of the composite material layer forming portion of the electrode body is as long as 567 mm or more in the electric storage element. Therefore, by increasing the width of the composite material layer forming portion of the electrode body to 567 mm or more, it is possible to use an electrode body with effectively increased energy density, so that the energy density of the storage element can be improved. can.

A container in which the electrode body is housed, and an electrode terminal projecting in the first direction from an end surface of the container in the first direction may be provided.

In the storage element, the electrode terminals protrude from the container, creating a space around the electrode terminals that is difficult to utilize. If this space is large, the energy density of the storage element as a whole, including the space concerned, will decrease. Therefore, in the electric storage element, the electrode terminal protrudes in the first direction from the end face of the container in the first direction. As a result, the electrode terminals protrude from the outer surface of the container with a small area, and the space around the electrode terminals that is difficult to utilize due to the protruding electrode terminals can be reduced, so that the energy density of the storage element can be reduced. can be improved.

Since the power storage device includes the power storage element described above, it is possible to improve the energy density. In the power storage device, if the length of the power storage element is long, the distance between two electrode terminals connected to a pair of external terminals may become long. In this case, if the pair of external terminals are arranged near the two electrode terminals, the pair of external terminals are arranged at distant positions, which may make it difficult to connect the power storage device to the outside. However, when the pair of external terminals are arranged close to each other, the length of the bus bar connecting the pair of external terminals and the two electrode terminals becomes long. For this reason, the pair of external terminals are the first electrode terminal close to the second storage element of the pair of first electrode terminals of the first storage element, and the pair of second electrode terminals of the second storage element. and a second electrode terminal close to the first storage element. As a result, in a power storage device having a power storage element capable of improving energy density, the length of the bus bar connecting the external terminal and the electrode terminal of the power storage element is suppressed from increasing, and the pair of external terminals can be placed close together.

Hereinafter, an electric storage element and an electric storage device according to embodiments (including modifications thereof) of the present invention will be described with reference to the drawings. All of the embodiments described below are generic or specific examples. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, manufacturing processes, order of manufacturing processes, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each figure, the same reference numerals are given to the same or similar components.

In the following description and drawings, the extending direction of the storage element container, the extending direction of the electrode body, the extending direction of the winding axis of the electrode body, the mixture layer formed portion and the mixture layer non-formed portion of the electrode body , the width direction of the composite material layer formed portion and the composite material layer non-formed portion, and the direction in which the pair of electrode terminals of the storage element are arranged are defined as the X-axis direction. The direction in which the pair of long sides of the container of the storage element are aligned (opposing direction), the direction in which the pair of flat portions of the electrode body are aligned (opposing direction), or the thickness direction of the container and the electrode body is defined as the Y-axis direction. The direction in which the pair of short sides (upper and bottom surfaces) of the storage element container are arranged (opposing direction), the direction in which the pair of curved portions of the electrode assembly are arranged (opposing direction), the height direction of the container and the electrode assembly, or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that cross each other (perpendicularly in this embodiment). Depending on the mode of use, the Z-axis direction may not be the vertical direction, but for convenience of explanation, the Z-axis direction will be described below as the vertical direction.

In the following description, the positive direction of the X-axis indicates the direction of the arrow on the X-axis, and the negative direction of the X-axis indicates the direction opposite to the positive direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Hereinafter, the X-axis direction may also be referred to as the first direction, the Z-axis direction may also be referred to as the second direction, and the Y-axis direction may also be referred to as the third direction. Expressions indicating relative directions or orientations, such as parallel and orthogonal, also include cases where the directions or orientations are not strictly speaking. Two directions are orthogonal, not only means that the two directions are completely orthogonal, but also substantially orthogonal, i.e., including a difference of about several percent also means

(Embodiment)
[1 General description of power storage device 10]
First, a general description of power storage device 10 in the present embodiment will be given. FIG. 1 is a perspective view showing the appearance of power storage device 10 according to the present embodiment. FIG. 1 is a diagram showing the inside of the exterior body 200 by seeing through the exterior body 200, and the exterior body 200 (and the pair of external terminals 300) is indicated by broken lines.

The power storage device 10 is a device that can charge electricity from the outside and discharge electricity to the outside, and has a substantially rectangular parallelepiped shape in the present embodiment. The power storage device 10 is a battery module (assembled battery) used for power storage, power supply, or the like. Specifically, the power storage device 10 is used for driving mobile bodies such as automobiles, motorcycles, water crafts, ships, snowmobiles, agricultural machinery, construction machinery, or railroad vehicles for electric railways, or for starting engines. Used as a battery or the like. Examples of such vehicles include electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and gasoline vehicles. Examples of railway vehicles for the electric railway include electric trains, monorails, linear motor cars, and hybrid trains having both diesel engines and electric motors. The power storage device 10 can also be used as a stationary battery or the like for home or business use.

As shown in FIG. 1 , the power storage device 10 includes a plurality of power storage elements 100 , an exterior body 200 housing the plurality of power storage elements 100 , and a pair of external terminals 300 . The power storage device 10 also includes a bus bar that connects the power storage elements 100 in series or in parallel, a bus bar that connects the power storage elements 100 and the external terminals 300, and the like, but illustration and description thereof are omitted. In addition to the components described above, the power storage device 10 includes spacers and double-sided tape placed between the plurality of power storage elements 100, an adhesive or filler for fixing the power storage elements 100 to the exterior body 200, and a plurality of power storage elements. Constraining members (end plates, side plates, etc.) that constrain 100, busbar frames that position the busbars, and electric devices such as circuit boards and relays that monitor or control the charging state and discharging state of the storage element 100. may be provided.

The exterior body 200 is a substantially rectangular parallelepiped (box-shaped) container (module case) that constitutes the exterior body of the power storage device 10 . That is, the exterior body 200 is arranged outside the plurality of power storage elements 100, fixes the plurality of power storage elements 100 at predetermined positions, and protects them from impacts and the like. The exterior body 200 is made of polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET). , polybutylene terephthalate (PBT), polyetheretherketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or It is formed of an insulating member such as a composite material, or a metal or the like coated with an insulating coating. The exterior body 200 thereby prevents the plurality of power storage elements 100 from coming into contact with an external metal member or the like. The exterior body 200 may be made of a conductive material such as metal as long as the insulation of the power storage element 100 is maintained. The "insulation" mentioned above means electrical insulation. The same applies to the following.

A pair of (positive electrode side and negative electrode side) external terminals 300 are provided on the exterior body 200 . The pair of external terminals 300 are positive and negative external connection terminals for charging electricity from the outside of the power storage device 10 and discharging electricity to the outside of the power storage device 10, and are made of aluminum, an aluminum alloy, It is made of a conductive member made of metal such as copper, copper alloy, iron, steel, stainless steel, or the like. In the present embodiment, the pair of external terminals 300 are arranged in the X-axis direction and protrude in the Z-axis positive direction at the X-axis direction central portion and the Y-axis negative direction end portion of the exterior body 200 .

The storage element 100 is a secondary battery (single battery) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. . The power storage element 100 has a long and flat rectangular parallelepiped shape (square shape) extending in the X-axis direction (first direction). The storage element 100 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 power storage element 100 may be a primary battery that can use stored electricity without being charged by the user, instead of a secondary battery. The storage element 100 may be a battery using a solid electrolyte. The storage element 100 may be a pouch-type storage element.

In the present embodiment, a plurality of (several tens, 48 in FIG. 1) power storage elements 100 are arranged side by side in the X-axis direction (first direction) and the Y-axis direction (third direction). Among the plurality of energy storage elements 100, the energy storage element 100 arranged in the positive direction of the X axis is also called the first energy storage element 101, and the energy storage element 100 arranged in the negative direction of the X axis is also called the second energy storage element 102. That is, a plurality (24 in FIG. 1) of the first storage elements 101 are arranged side by side in the Y-axis direction in the X-axis plus direction, and a plurality (24 in FIG. 1) of the second storage elements 101 are arranged in the X-axis minus direction. Elements 102 are arranged side by side in the Y-axis direction. As a result, the plurality of first storage elements 101 and the plurality of second storage elements 102 are arranged side by side in the X-axis direction. Thus, the plurality of power storage elements 100 included in the power storage device 10 have the first power storage element 101 and the second power storage element 102 arranged in the X-axis direction (first direction).

Each of the plurality of power storage elements 100 has a pair of (positive electrode side and negative electrode side) electrode terminals 120 (121 and 122) arranged in the X-axis direction (first direction) (see FIG. 2). A detailed description of the configuration of the storage element 100 including the pair of electrode terminals 120 (121 and 122) will be given later.

The pair of electrode terminals 120 (121 and 122) of the first storage element 101 are also referred to as first electrode terminals 120 (121 and 122). Similarly, the pair of electrode terminals 120 (121 and 122) of the second storage element 102 are also referred to as second electrode terminals 120 (121 and 122). That is, each of the plurality of first storage elements 101 has a pair of first electrode terminals 120 (121 and 122) aligned in the X-axis direction (first direction). Similarly, each of the plurality of second storage elements 102 has a pair of second electrode terminals 120 (121 and 122) aligned in the X-axis direction (first direction).

In such a configuration, the first electrode terminals 120, the second electrode terminals 120, the first electrode terminal 120 and the second electrode terminal 120, the first electrode terminal 120 and the external terminal 300, and the second electrode terminal 120 and An external terminal 300 is connected via a bus bar or the like or directly. Thereby, the plurality of first storage elements 101 and the plurality of second storage elements 102 are connected in series or in parallel. In this embodiment, the plurality of first storage elements 101 and the plurality of second storage elements 102 are all connected in series.

Specifically, the first electrode terminal 120 of the first storage element 101 located at the end in the Y-axis negative direction among the plurality of first storage elements 101 and the Y-axis terminal of the plurality of second storage elements 102 The second electrode terminal 120 of the second storage element 102 located at the end in the negative direction is connected to the pair of external terminals 300 . In the present embodiment, the first electrode terminal 122 of the first storage element 101 and the second electrode terminal 102 of the second storage element 102 are connected to the first storage element 101 and the second storage element 102 at the ends in the Y-axis negative direction. The terminals 121 are connected to a pair of external terminals 300 via bus bars or the like.

That is, in the first storage element 101 at the end in the Y-axis negative direction, the first electrode terminal 121 is the electrode terminal farthest from the second storage element 102 among the pair of first electrode terminals 120 of the first storage element 101. is. The first electrode terminal 122 is the electrode terminal closest to the second storage element 102 among the pair of first electrode terminals 120 of the first storage element 101 . Similarly, in the second storage element 102 at the end in the Y-axis negative direction, the second electrode terminal 121 is the electrode closest to the first storage element 101 among the pair of second electrode terminals 120 of the second storage element 102 . terminal. The second electrode terminal 122 is the electrode terminal farthest from the first storage element 101 among the pair of second electrode terminals 120 of the second storage element 102 . Therefore, the first electrode terminal 122 of the first storage element 101 close to the second storage element 102 and the second electrode terminal 121 of the second storage element 102 close to the first storage element 101 are connected to the pair of external terminals 300. Connected.

In this way, the pair of external terminals 300 includes the first electrode terminal 122 of the pair of first electrode terminals 120 of the first storage element 101 that is closer to the second storage element 102, and the pair of external terminals 300 that the second storage element 102 has. and the second electrode terminal 121 close to the first storage element 101 among the second electrode terminals 120 of the . The pair of external terminals 300 are located directly above the first storage element 101 at the end in the negative Y-axis direction and the second storage element 102 at the end in the negative Y-axis direction (positive Z-axis direction) or in the vicinity thereof. preferably located. The pair of external terminals 300 includes a first electrode terminal 122 close to the second storage element 102 of the first storage element 101 and a second electrode terminal 121 close to the first storage element 101 of the second storage element 102. (in the Z-axis plus direction) or in the vicinity thereof.

A plurality of first storage elements 101 are electrically connected by connecting the first electrode terminals 120 of adjacent first storage elements 101 to each other via a bus bar or the like. In the present embodiment, the first electrode terminals 121 and the first electrode terminals 122 of the adjacent first storage elements 101 are arranged at opposite positions in the X-axis direction. A plurality of first storage elements 101 are connected in series by connecting first electrode terminals 121 and first electrode terminals 122 of adjacent first storage elements 101 via a bus bar or the like. The same applies to the second storage element 102 as well.

The first electrode terminal 120 of the first storage element 101 located at the end of the plurality of first storage elements 101 in the positive direction of the Y axis, and the end of the plurality of second storage elements 102 in the positive direction of the Y axis is connected to the second electrode terminal 120 of the second storage element 102 located at , via a bus bar or the like. As a result, the first storage element 101 at the end in the positive Y-axis direction and the second storage element 102 at the end in the positive Y-axis direction are electrically connected. In the present embodiment, an even number of first storage elements 101 are arranged, and an even number of second storage elements 102 are also arranged. As a result, the first electrode terminal 121 of the first storage element 101 at the end in the positive Y-axis direction becomes the electrode terminal closer to the second storage element 102 out of the pair of first electrode terminals 120 . Similarly, in the second storage element 102 at the end in the positive direction of the Y axis, the second electrode terminal 122 is the electrode terminal closer to the first storage element 101 out of the pair of second electrode terminals 120 . As a result, the first electrode terminal 121 of the first storage element 101 close to the second storage element 102 and the second electrode terminal 122 of the second storage element 102 close to the first storage element 101 are connected via a bus bar or the like. As a result, the first storage element 101 and the second storage element 102 are connected in series.

The number of power storage elements 100 to be arranged is not limited, and dozens of power storage elements 100 may be arranged, or only a few power storage elements 100 may be arranged. However, as described above, an even number of first storage elements 101 and an even number of second storage elements 102 are preferably arranged. The number of arranged first storage elements 101 and the number of arranged second storage elements 102 are preferably the same or close to each other. Either the plurality of first storage elements 101 or the plurality of second storage elements 102 may be connected in parallel.

[2 Explanation of storage element 100]
Next, the configuration of the storage element 100 will be described in detail. FIG. 2 is a perspective view showing the appearance of the storage element 100 according to the present embodiment and the electrode body 130 included in the storage element 100. As shown in FIG. In FIG. 2 , the electrode body 130 housed in the container 110 of the electric storage element 100 is taken out from the container 110 and shown below the electric storage element 100 . Since the power storage elements 100 (the first power storage element 101 and the second power storage element 102) of the power storage device 10 all have the same configuration, the configuration of one power storage element 100 will be described in detail below.

As shown in FIG. 2, the storage element 100 has a container 110 and the pair of electrode terminals 120 (121 and 122) (positive electrode side and negative electrode side) described above. 130 and a pair of (positive electrode side and negative electrode side) current collectors (not shown) are accommodated. An electrolytic solution (non-aqueous electrolyte) is sealed inside the container 110, and gaskets are arranged between the electrode terminals 120 and current collectors and the container 110. omitted. There is no particular limitation on the type of the electrolytic solution as long as it does not impair the performance of the storage element 100, and various types can be selected.

In addition to the components described above, the electric storage element 100 may have a spacer disposed on the side of the electrode body 130, an insulating film wrapping the electrode body 130 and the like, and the like. An insulating film (shrink tube or the like) covering the outer surface of the container 110 may be arranged around the container 110 . The material of the insulating film is not particularly limited as long as it can ensure the insulation required for the storage element 100, but any insulating resin, epoxy resin, kapton, Teflon (registered trademark), silicon, polyisoprene, and polyvinyl chloride.

The container 110 is a cuboid-shaped (square or box-shaped) case extending in the X-axis direction (first direction). The material of the container 110 is not particularly limited, and can be, for example, a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel plate, but resin can also be used. The container 110 is provided with a gas discharge valve that releases the pressure when the pressure inside the container 110 is excessively increased, and an injection part for injecting an electrolytic solution into the inside of the container 110. may

The container 110 has a pair of long side surfaces 111 extending in the X-axis direction on both side surfaces in the Y-axis direction, and a pair of short side surfaces 112 extending in the X-axis direction on both side surfaces in the Z-axis direction. has a pair of terminal placement surfaces 113 extending in the Z-axis direction. The long side surface 111 is a rectangular and planar side surface elongated in the X-axis direction, which forms the long side surface of the container 110, and is arranged to face in the Y-axis direction. The long side 111 is adjacent to the short side 112 and the terminal arrangement surface 113 and has a larger area than the short side 112 . The short side surface 112 is a rectangular and planar side surface elongated in the X-axis direction, which forms the short side surface of the container 110, and is arranged to face in the Z-axis direction. The short side 112 is adjacent to the long side 111 and the terminal arrangement surface 113 and has a smaller area than the long side 111 . The terminal arrangement surface 113 is a rectangular and planar side surface on which the electrode terminal 120 is arranged, and is arranged to face in the X-axis direction.

The electrode terminals 120 (121 and 122) protrude in the X-axis direction (first direction) from the end face of the container 110 in the X-axis direction (first direction) on both sides of the container 110 in the X-axis direction (first direction). terminal members (a positive electrode terminal and a negative electrode terminal) of the storage element 100 arranged in a state. In this embodiment, of the pair of electrode terminals 120, the electrode terminal 121 is the positive terminal and the electrode terminal 122 is the negative terminal. Specifically, the electrode terminal 121 is fixed to the terminal arrangement surface 113 of the container 110 in the positive direction of the X axis, and is arranged to protrude from the terminal arrangement surface 113 in the positive direction of the X axis. The electrode terminal 122 is fixed to the terminal arrangement surface 113 of the container 110 in the negative direction of the X axis, and arranged so as to protrude from the terminal arrangement surface 113 in the negative direction of the X axis.

The electrode terminals 120 (121 and 122) are electrically connected to the positive and negative plates of the electrode body 130 via current collectors. That is, the electrode terminal 120 leads the electricity stored in the electrode body 130 to the external space of the storage element 100 and also introduces the electricity into the internal space of the storage element 100 to store the electricity in the electrode body 130 . is a metal member. The electrode terminal 120 is made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

The electrode body 130 is a power storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. A microporous sheet made of resin, a non-woven fabric, or the like can be used as the separator. The positive electrode plate is obtained by forming a positive electrode mixture layer on a positive electrode base material, which is a long belt-shaped collector foil made of metal such as aluminum or an aluminum alloy. The negative electrode plate is obtained by forming a negative electrode mixture layer on a negative electrode base material, which is a long band-shaped collector foil made of a metal such as copper or a copper alloy. Materials that are stable against oxidation-reduction reactions during charging and discharging, such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc., are used for the positive and negative electrode base materials. Any known material can be used as appropriate. The positive electrode mixture layer contains a positive electrode active material, a conductive aid, and a binder, and the negative electrode mixture layer contains a negative electrode active material, a conductive aid, and a binder. As the positive electrode active material used for the positive electrode mixture layer and the negative electrode active material used for the negative electrode mixture layer, known materials can be appropriately used as long as they can intercalate and deintercalate lithium ions.

As positive electrode active materials, polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn ₂ Spinel-type lithium manganese oxides such as O ₄ and LiMn _1.5 Ni _0.5 O ₄ , LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) Lithium transition metal oxides, etc., can be used. Examples of negative electrode active materials include lithium metal, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as Wood's alloys). , alloys that can absorb and release lithium, carbon materials (e.g. graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), silicon oxides, metal oxides, lithium metal oxides ( Li ₄ Ti ₅ O ₁₂ , etc.), polyphosphate compounds, or compounds of transition metals and group 14 to group 16 elements, such as Co ₃ O ₄ and Fe ₂ P, which are generally called conversion negative electrodes. .

The electrode body 130 is formed by alternately stacking and winding a positive electrode plate, a negative electrode plate, and two separators. In the present embodiment, electrode body 130 includes electrode plates (positive electrode plate and negative electrode plate) on which composite material layers are formed as described above, and is wound around winding axis R extending in the X-axis direction (first direction). It is a wound electrode body (so-called vertically wound electrode body) formed by winding. The winding axis R is a virtual axis that is the central axis when the positive electrode plate, the negative electrode plate, etc. are wound. A straight line. Thereby, the electrode body 130 is long in the X-axis direction, and the length in the Z-axis direction (second direction) is longer than the length in the Y-axis direction (third direction) (thickness in the Y-axis direction). It has a flat shape (elliptical cylinder shape).

Specifically, in the electrode body 130, the positive electrode plate and the negative electrode plate are wound while being shifted in the direction along the winding axis R (the X-axis direction (first direction)) with the separator interposed therebetween. Each of the positive electrode plate and the negative electrode plate has a portion where the positive electrode material layer and the negative electrode material layer are not formed (coated) and the positive electrode base material and the negative electrode base material are exposed at the ends of the respective shifted directions. there is That is, the electrode plates (positive electrode plate and negative electrode plate) are arranged at the composite material layer forming portion 131 on which the composite material layer is formed and at the end portion in the X-axis direction (first direction) of the composite material layer forming portion 131. , and mixture layer non-formed portions 132 and 133 where no mixture layer is formed.

The mixture layer forming portion 131 is a portion of the positive electrode base material and the negative electrode base material on which the positive electrode mixture layer and the negative electrode mixture layer are formed, and a portion composed of the positive electrode mixture layer and the negative electrode mixture layer. In other words, the composite layer forming portion 131 is a main body portion of the electrode body 130 in which the positive electrode composite material layer and the negative electrode composite material layer of the electrode body 130 are formed. , as a whole, has an elongated cylindrical shape extending in the X-axis direction. As a result, the composite material layer forming portion 131 has a pair of composite material layer flat portions 131a on both sides in the Y-axis direction, and a pair of composite material layer curved portions 131b on both sides in the Z-axis direction.

The compound layer flat portion 131a is a rectangular and flat portion that connects the ends of the pair of compound layer curved portions 131b and extends parallel to the XZ plane facing the Y-axis direction. The compound layer curved portion 131b is a curved portion extending in the X-axis direction, curved in a semicircular arc shape so as to protrude in the Z-axis direction when viewed from the X-axis direction. The curved shape of the composite layer curved portion 131b is not limited to a semicircular arc shape, and may be a part of an elliptical shape or the like, and may be curved in any way. The outer surface of the composite material layer flat portion 131a facing in the Y-axis direction is not limited to being flat, and the outer surface may be slightly concave or slightly bulging.

The composite material layer non-formed portion 132 is a portion of the positive electrode substrate where the positive electrode composite material layer is not formed. That is, the composite material layer non-forming portion 132 is an end portion of the electrode body 130 in the X-axis positive direction, which protrudes from the composite material layer-forming portion 131 of the electrode body 130 in the X-axis positive direction. By being wound around, it has a substantially long cylindrical shape as a whole. As a result, the composite material layer non-forming portion 132 has a pair of flat end portions 132a on both sides in the Y-axis direction, and a pair of curved end portions 132b on both sides in the Z-axis direction. The composite material layer non-formation portion 133 is a portion of the negative electrode substrate where the negative electrode composite material layer is not formed. That is, the composite material layer non-formed portion 133 is an end portion of the electrode body 130 in the negative X-axis direction that protrudes from the composite material layer formed portion 131 of the electrode body 130 in the negative direction of the X-axis. By being wound around, it has a substantially long cylindrical shape as a whole. As a result, the composite material layer non-forming portion 133 has a pair of flat end portions 133a on both sides in the Y-axis direction, and a pair of curved end portions 133b on both sides in the Z-axis direction.

The end flat portion 132a is a rectangular and flat portion that connects the ends of the pair of end curved portions 132b and extends parallel to the XZ plane and in the Z-axis direction. The end curved portion 132b is a curved portion curved in a semicircular arc shape so as to protrude in the Z-axis direction when viewed from the X-axis direction. The curved shape of the end curved portion 132b is not limited to a semicircular arc shape, and may be a part of an elliptical shape or the like, and may be curved in any way. The flat end portion 132a is not limited to having a flat outer surface facing in the Y-axis direction, and the outer surface may be slightly concave or slightly bulging. The flat end portion 133a and the curved end portion 133b of the composite material layer non-formation portion 133 have the same configuration as the flat end portion 132a and the curved end portion 132b described above, so detailed description thereof will be omitted. .

The collectors are conductive collectors (positive collector and negative collector) that are electrically and mechanically connected to the electrode terminal 120 and the electrode body 130 . Specifically, the positive electrode current collector is electrically and mechanically connected (joined) to the electrode terminal 121 and the end flat portion 132 a of the composite material layer non-formed portion 132 of the electrode assembly 130 . The negative electrode current collector is electrically and mechanically connected (joined) to the electrode terminal 122 and the end flat portion 133 a of the composite material layer non-formed portion 133 of the electrode body 130 . The positive current collector is made of aluminum or an aluminum alloy, like the positive base material of the positive plate of the electrode body 130. The negative current collector is made of copper or copper, like the negative base material of the negative plate of the electrode body 130. It is made of an alloy or the like. The electrode terminal 120 (121 and 122) and the composite material layer non-formed portions 132 and 133 of the electrode body 130 may be directly connected without a current collector.

[3 Description of Sizes of Container 110 and Electrode Body 130 of Storage Element 100]
Next, the sizes of the container 110 and the electrode body 130 of the storage element 100 will be described in detail with reference to FIGS. 2 and 3. FIG. FIG. 3 is a front view showing the size of electrode assembly 130 according to the present embodiment.

As shown in FIG. 2, in the electric storage element 100, the length of the container 110 in the X-axis direction (first direction) is defined as a first container length L1, and the length of the container 110 in the Z-axis direction (second direction) ( height) is the second container length H1, and the length (width, thickness) of the container 110 in the Y-axis direction (third direction) is the third container length W1. The first container length L1 can also be defined as the length of the long side 111 in the X-axis direction, the length of the short side 112 in the X-axis direction, or the distance between the pair of terminal placement surfaces 113 . The second container length H1 can also be defined as the length of the long side 111 in the Z-axis direction, the length of the terminal placement surface 113 in the Z-axis direction, or the distance between the pair of short sides 112 . The third container length W1 is also defined as the length (width) of the short side 112 in the Y-axis direction, the length (width) of the terminal arrangement surface 113 in the Y-axis direction, or the distance between the pair of long sides 111. can.

Similarly, the length of the electrode body 130 in the X-axis direction (first direction) is the first electrode body length L2, and the length (height) of the electrode body 130 in the Z-axis direction (second direction) is the second electrode body length L2. It is assumed that the body length is H2, and the length (width and thickness) of the electrode body 130 in the Y-axis direction (third direction) is taken as the third electrode body length W2. The first electrode body length L2 can also be defined as the distance between both end surfaces of the composite material layer non-formed portions 132 and 133 in the X-axis direction. The second electrode body length H2 can also be defined as the distance between both end surfaces of the pair of composite material layer curved portions 131b of the composite material layer forming portion 131 in the Z-axis direction. The third electrode body length W2 can also be defined as the distance between both end surfaces of the pair of composite material layer flat portions 131a of the composite material layer forming portion 131 in the Y-axis direction.

As shown in FIG. 3, in the electrode assembly 130, the width of the positive electrode plate in the X-axis direction (first direction) is defined as a positive electrode plate width A, and the width of the negative electrode plate in the X-axis direction (first direction) is defined as a negative electrode plate width B. and The width of the composite material layer formed portion 131 in the X-axis direction (first direction) is defined as the composite material layer formed portion width C1, and the width of the composite material layer non-formed portion 132 in the X-axis direction (first direction) is defined as the composite material layer non-width. The width of the formed portion is C2, and the width of the composite material layer non-formed portion 133 in the X-axis direction (first direction) is defined as the composite material layer non-formed portion width C3. In the present embodiment, the composite material layer non-formed portion width C2 is the composite material layer non-formed portion width of the positive electrode, and the composite material layer non-formed portion width C3 is the composite material layer non-formed portion width of the negative electrode.

In FIG. 3, the width of the positive electrode mixture layer in the X-axis direction and the width of the negative electrode mixture layer in the X-axis direction are both illustrated as the same length as the width of the mixture layer forming portion C1. , the width of the negative electrode mixture layer in the X-axis direction is slightly larger than the width of the positive electrode mixture layer in the X-axis direction. That is, the negative electrode mixture layer overlaps the mixture layer non-formed portion 132 in the X-axis direction. That is, in FIG. 3, the composite material layer non-forming portion width C2 indicates the portion not overlapping the negative electrode composite material layer, but the actual composite material layer non-forming portion width C2 is the portion overlapping the negative electrode composite layer. also has a width of Therefore, hereinafter, the width of the positive electrode mixture layer in the X-axis direction is defined as a mixture layer forming portion width C1 (positive electrode), and the width of the negative electrode mixture layer in the X-axis direction is defined as a mixture layer forming portion width C1 (negative electrode). will be described separately. That is, the positive electrode plate width A is the total value of the composite material layer forming portion width C1 (positive electrode) and the composite material layer non-forming portion width C2, and the negative electrode plate width B is the composite material layer forming portion width C1 (negative electrode). and the composite material layer non-formed portion width C3. Without distinguishing between the composite material layer forming width C1 (positive electrode) and the composite material layer forming width C1 (negative electrode), one of the composite material layer forming width C1 (positive electrode) and the composite material layer forming width C1 (negative electrode) Alternatively, when referring to both, it is simply indicated as the composite material layer forming portion width C1.

Table 1 shows the size of the container 110 in Comparative Examples 1 to 3 and Examples 1 to 7 in the above configuration. Table 1 is a table showing sizes of containers 110 in Comparative Examples 1 to 3 and Examples 1 to 7 in the storage device 100 according to the present embodiment. Specifically, Table 1 shows the first container length L1, the second container length H1, the third container length W1, and the third One container length L1/second container length H1 (first container length L1/second container length H1) is shown.

As shown in Table 1, in Comparative Examples 1 to 3 and Examples 1 to 7, the values of the second container length H1 and the third container length W1 are fixed, and the value of the first container length L1 is are changing. That is, from Comparative Example 1 to Example 7, the value of the first container length L1 (the length of the container 110 in the X-axis direction (first direction)) is gradually increased. In Comparative Example 1, the first container length L1=100 mm, the second container length H1=145 mm, the third container length W1=22 mm, and the first container length L1/second container length H1=0. 7. In Example 1, the first container length L1=250 mm, the second container length H1=145 mm, the third container length W1=22 mm, and the first container length L1/second container length H1=1. 7.

Table 2 shows the sizes of the electrode bodies 130 in Comparative Examples 1 to 3 and Examples 1 to 7. Table 2 is a table showing the sizes of the electrode bodies 130 in Comparative Examples 1 to 3 and Examples 1 to 7 in the energy storage device 100 according to the present embodiment. Specifically, Table 2 shows the first electrode body length L2, the second electrode body length H2, the third electrode body length W2, and First electrode body length L2/second electrode body length H2 (first electrode body length L2/second electrode body length H2) is shown.

As shown in Table 2, in Comparative Examples 1 to 3 and Examples 1 to 7, the values of the second electrode body length H2 and the third electrode body length W2 are fixed, and the value of the first electrode body length L2 is being changed. That is, from Comparative Example 1 to Example 7, as the value of the first container length L1 was gradually increased, the value of the first electrode body length L2 (the X-axis direction (first direction) of the electrode body 130) length) is gradually increasing. In Comparative Example 1, the first electrode body length L2 = 96.7 mm, the second electrode body length H2 = 135.6 mm, the third electrode body length W2 = 19.4 mm, and the first electrode body length L2/second electrode Body length H2=0.7. In Example 1, the first electrode body length L2 = 246.7 mm, the second electrode body length H2 = 135.6 mm, the third electrode body length W2 = 19.4 mm, and the first electrode body length L2/second electrode Body length H2=1.8.

Table 3 shows the sizes of the composite material layer formed portion 131 and the composite material layer non-formed portions 132 and 133 of the electrode body 130 in Comparative Examples 1 to 3 and Examples 1 to 7. Table 3 shows the composite material layer formed portion 131 and the composite material layer non-formed portions 132 and 133 of the electrode body 130 in Comparative Examples 1 to 3 and Examples 1 to 7 in the energy storage device 100 according to the present embodiment. It is a table showing sizes. Specifically, Table 3 shows the composite material layer forming portion width C1 (positive electrode), the composite material layer non-forming portion width C2, and the composite material layer of the electrode bodies 130 in Comparative Examples 1 to 3 and Examples 1 to 7. Forming portion width C1 (positive electrode)/mixture layer non-forming portion width C2, composite material layer forming portion width C1 (negative electrode), composite material layer non-forming portion width C3, and composite material layer forming portion width C1 (negative electrode)/ It shows the width of the composite material layer non-forming portion C3.

As shown in Table 3, in Comparative Examples 1 to 3 and Examples 1 to 7, the values of the composite material layer non-forming portion widths C2 and C3 are fixed, and the composite material layer forming portion width C1 (positive electrode) and The value of the material layer forming portion width C1 (negative electrode) is changed. That is, from Comparative Example 1 to Example 7, as the value of the first container length L1 (and the first electrode body length L2) was gradually increased, the composite material layer forming portion width C1 (positive electrode) and the composite material The value of the layer forming portion width C1 (negative electrode) (the width of the mixture layer forming portion 131 in the X-axis direction (first direction)) also gradually increases. In Comparative Example 1, the composite material layer forming portion width C1 (positive electrode)=66.2 mm, the composite material layer non-forming portion width C2=14.2 mm, the composite material layer forming portion width C1 (positive electrode)/the composite material layer non-forming portion. Width C2 = 4.7, composite material layer forming portion width C1 (negative electrode) = 70.3 mm, composite material layer non-forming portion width C3 = 14.2 mm, and composite material layer forming portion width C1 (negative electrode)/composite material The layer non-forming portion width C3=5.0. In Example 1, the composite material layer forming portion width C1 (positive electrode)=216.2 mm, the composite material layer non-forming portion width C2=14.2 mm, the composite material layer forming portion width C1 (positive electrode)/the composite material layer non-forming portion. Width C2 = 15.2, composite material layer forming portion width C1 (negative electrode) = 220.3 mm, composite material layer non-forming portion width C3 = 14.2 mm, and composite material layer forming portion width C1 (negative electrode)/composite material The layer non-forming portion width C3=15.5.

Next, the configuration of the horizontally wound electrode assembly 140 will be described below as a comparison target with the vertically wound electrode assembly 130 . FIG. 4 is a front view showing the configuration of an electrode assembly 140, which is a horizontally wound electrode assembly, for comparison with electrode assembly 130, which is a vertically wound electrode assembly, according to the present embodiment. Specifically, FIG. 4 is a diagram corresponding to FIG.

As shown in FIG. 4, the electrode body 140 is formed by winding an electrode plate (a positive electrode plate and a negative electrode plate) on which a composite material layer is formed around a winding axis Rz extending in the Z-axis direction. It is a horizontally wound electrode body. The electrode body 140 has a flat shape (elliptical cylinder shape) that is long in the X-axis direction, oblong when viewed from the Z-axis direction, and thin in the Y-axis direction. The electrode body 140 includes a composite material layer forming portion 141 having a composite material layer formed thereon, and a composite material layer non-formed tab protruding from the composite material layer forming portion 141 in the Z-axis positive direction and having no composite material layer formed thereon. and

portions

142 and 143 .

The length of the electrode body 140 in the X-axis direction is the same as the length of the electrode body 130 in the X-axis direction (first electrode body length L2). The electrode body 140 has a length in the Z-axis direction (the total length of the composite material layer formed portion 141 and the composite material layer non-formed portions 142 and 143) and a length in the Z-axis direction of the electrode body 130 (second It is the same as the electrode body length H2). It is assumed that the electrode body 140 has the same width (third electrode body length W2) as the electrode body 130 also in the Y-axis direction. A composite material layer non-formed portion width C4, which is the amount of protrusion of the composite material layer

non-formed portions

142 and 143 in the Z-axis positive direction, is the protrusion of the composite material layer non-formed portion 132 or 133 of the electrode assembly 130 in the X-axis direction. The length is the same as the width C2 or C3 of the composite material layer non-formation portion, which is the amount. In the present embodiment, as shown in Table 3, the widths C2 and C3 of the mixture non-formed portion are the same length, so the width C4 of the mixture non-formed portion is It is the same length as C2 and C3.

On the premise of such a configuration, in Comparative Examples 1 to 3 and Examples 1 to 7, the energy densities of the energy storage element 100 using the vertically wound electrode body and the energy density of the energy storage element using the horizontally wound electrode body are shown in Table 4, Figures 5A and 5B. The energy densities shown in Table 4, FIGS. 5A and 5B below indicate the energy densities in the portions excluding the electrode terminals.

Table 4 shows the difference in energy between the energy storage device 100 using the vertically wound electrode assembly according to the present embodiment and the energy storage device using the horizontally wound electrode assembly in Comparative Examples 1 to 3 and Examples 1 to 7. Fig. 10 is a table showing a comparison of densities; Specifically, Table 4 shows, in Comparative Examples 1 to 3 and Examples 1 to 7, the storage element 100 using the vertically wound electrode body 130 and the horizontally wound electrode body. The energy density with respect to the electric storage element using the body 140, the difference therebetween, and the capacity of the electric storage element 100 are shown.

5A and 5B show, in the energy storage element 100 using the vertically wound electrode body according to the present embodiment, energy storage elements using the horizontally wound electrode bodies in Comparative Examples 1 to 3 and Examples 1 to 7. is a graph showing a comparison of energy densities with Specifically, FIG. 5A shows, in Comparative Examples 1 to 3 and Examples 1 to 7, a power storage element 100 using an electrode body 130 that is a vertically wound electrode body and an electrode that is a horizontally wound electrode body. 4 is a graph showing changes in energy density with a power storage element using the body 140 with respect to the width C1 of the composite material layer formed portion/the width C2 of the non-composite material layer formed portion. FIG. 5B shows, in Comparative Examples 1 to 3 and Examples 1 to 7, the storage element 100 using the vertically wound electrode body 130 and the horizontally wound electrode body 140. 4 is a graph showing a change in difference in energy density from a power storage element with respect to width C1 of a mixture layer formed portion/width C2 of a portion not formed with a mixture layer. 5A and 5B, the value of the composite material layer forming portion width C1 (positive electrode) is used as the composite material layer forming portion width C1, but when the value of the composite material layer forming portion width C1 (negative electrode) is used also show a similar tendency.

As shown in Table 4, FIGS. 5A and 5B, in Comparative Examples 1 to 7, the energy storage element 100 using the electrode body 130 which is the vertically wound electrode body and the electrode body which is the horizontally wound electrode body The energy densities of both of the storage elements using 140 are increased, but the energy density of the storage element 100 using the electrode assembly 130 increases at a faster rate. Therefore, in Comparative Examples 1 to 3, the energy density of the energy storage device 100 using the electrode body 130 is lower than or equal to that of the energy density of the energy storage device using the electrode body 140, but in Examples 1 to 7, the energy density of the electrode The energy density is higher than that of the electric storage device using the body 140 . That is, in Example 1, the energy density of the storage device 100 using the electrode assembly 130 is 235 Wh/L, exceeding the energy density of 230 Wh/L of the storage device using the electrode assembly 140 . The capacity of the storage device 100 in Example 1 is 52.9 Ah.

For this reason, the configurations of the storage elements 100 in Examples 1 to 7 are preferable. Specifically, as shown in Table 1, in Examples 1 to 7, the first container length L1 is 250 mm or more, so the first container length L1 (the X-axis direction (first direction) of the container 110 is 250 mm or more, the energy density of the storage element 100 can be improved. In Examples 1 to 7, since the first container length L1/second container length H1 is 1.7 or more, the first container length L1 is equal to the second container length H1 (the Z-axis direction of the container 110 When the length (height) in the second direction is 1.7 times or more or 2 times or more, the energy density of the storage element 100 can be improved.

As shown in Table 2, in Examples 1 to 7, the length L2 of the first electrode body was 246.7 mm or more, so the length L2 of the first electrode body (the length of the first electrode body 130 in the X-axis direction (first direction) One length) is 247 mm or more or 250 mm or more, the energy density of the storage element 100 can be improved. In Examples 1 to 7, the first electrode body length L2/second electrode body length H2 is 1.8 or more. When it is 1.8 times or more or 2 times or more of the second length in the direction (second direction), the energy density of the storage element 100 can be improved. From Tables 2 and 3, in Examples 1 to 7, the composite material layer forming portion width C1 is 1.6 times or more the length H2 of the second electrode body. When it is 1.6 times or more or 2 times or more the body length H2, the energy density of the storage element 100 can be improved.

As shown in Table 3, in Examples 1 to 7, the composite material layer forming portion width C1 (positive electrode) is 216.2 mm or more, and the composite material layer forming portion width C1 (negative electrode) is 220.3 mm or more. , when the composite material layer forming portion width C1 (the width of the composite material layer forming portion 131 in the X-axis direction (first direction)) is 217 mm or more or 220 mm or more, the energy density of the power storage element 100 is improved. can be done. In Examples 1 to 7, the composite material layer forming portion width C1 (positive electrode)/the composite material layer non-forming portion width C2 is 15.2 or more, and the composite material layer forming portion width C1 (negative electrode)/the composite material layer non-forming is 15.2 or more. Since the portion width C3 is 15.5 or more, the composite material layer forming portion width C1 is 15.2 times or more the composite material layer non-forming portion width C2 or C3 (the width of the composite material layer non-forming portion 132 or 133). Alternatively, when it is 16 times or more, the energy density of the storage element 100 can be improved.

As shown in Table 4, in Examples 1 to 7, the capacity of the storage element 100 is 52.9 Ah or more, so when the capacity of the storage element 100 is 53 Ah or more, the energy density of the storage element 100 is improved can be achieved.

As shown in Table 4, FIGS. 5A and 5B, the energy density of the storage element 100 is effectively increased from Example 1 to Example 3 (the increase in the value of “vertical winding-horizontal winding” is big). Therefore, in Examples 3 to 7, the electrode body 130 with effectively increased energy density can be used, so that the energy density of the storage element 100 can be improved.

For this reason, the configurations of the storage elements 100 in Examples 3 to 7 are preferable. Specifically, as shown in Table 1, the first container length L1 is preferably 600 mm or more, and the first container length L1/second container length H1 is 4.1 or more or 5 or more. is preferred. As shown in Table 2, the first electrode body length L2 is preferably 597 mm or more or 600 mm or more, and the first electrode body length L2/second electrode body length H2 is preferably 4.4 or more or 5 or more. preferable. That is, the first electrode body length L2 (the first length of the electrode body 130 in the X-axis direction (first direction)) is equal to the second electrode body length H2 (the second electrode body length H2 (the second length of the electrode body 130 in the Z-axis direction (second direction)). It is preferably 4.4 times or more, or 5 times or more of the two lengths). From Tables 2 and 3, it is preferable that the composite material layer forming portion width C1 is 4.2 times or more, or 5 times or more the length H2 of the second electrode body. As shown in Table 3, it is preferable that the composite material layer forming portion width C1 is 567 mm or more or 570 mm or more, and the composite material layer forming portion width C1/the composite material layer non-forming portion width C2 or C3 is 40 or more. is preferred. That is, the composite material layer forming portion width C1 (the width of the composite material layer forming portion 131 in the X-axis direction (first direction)) is equal to the composite material layer non-forming portion width C2 or C3 (the composite material layer non-forming portion 132 or 133 width) is preferably 40 times or more. As shown in Table 4, it is preferable that the capacity of the storage element 100 is 132 Ah or more.

As shown in Table 4, FIGS. 5A and 5B, in Examples 1 to 7, the energy density of the storage element 100 can be improved. is preferred. Specifically, as shown in Table 1, the first container length L1 is preferably 2000 mm or less, and the first container length L1/second container length H1 is 13.8 or less or 13 or less. is preferred. As shown in Table 2, the first electrode body length L2 is preferably 1996 mm or less or 1990 mm or less, and the first electrode body length L2/second electrode body length H2 is preferably 14.7 or less or 14 or less. preferable. That is, the first electrode body length L2 (the first length of the electrode body 130 in the X-axis direction (first direction)) is equal to the second electrode body length H2 (the second electrode body length H2 (the second length of the electrode body 130 in the Z-axis direction (second direction)). It is preferably not more than 14.7 times or not more than 14 times the length (two lengths). From Tables 2 and 3, it is preferable that the composite material layer forming portion width C1 is 14.5 times or less or 14 times or less the length H2 of the second electrode body. As shown in Table 3, the composite material layer forming portion width C1 is preferably 1970 mm or less or 1966 mm or less, and the composite material layer forming portion width C1/the composite material layer non-forming portion width C2 or C3 is 138 or less or 130 or less. is preferred. That is, the composite material layer forming portion width C1 (the width of the composite material layer forming portion 131 in the X-axis direction (first direction)) is equal to the composite material layer non-forming portion width C2 or C3 (the composite material layer non-forming portion 132 or 133 width) is preferably 138 times or less or 130 times or less. As shown in Table 4, it is preferable that the capacity of the storage element 100 is 448 Ah or less.

In Examples 6 and 7, as shown in Table 2, the first electrode body length L2 of the electrode body 130 was too long, making formation of the electrode body 130 difficult. As shown, the energy density of the storage element 100 does not increase much (the amount of increase in the numerical value of “longitudinal winding-horizontal winding” is small). Therefore, in Examples 1 to 5, it is possible to improve the energy density of the storage element 100 while easily forming the electrode body 130 .

For this reason, the configurations of the storage elements 100 in Examples 1 to 5 are preferable. Specifically, as shown in Table 1, the first container length L1 is preferably 1200 mm or less, and the first container length L1/second container length H1 is 8.3 or less or 8 or less. is preferred. As shown in Table 2, the first electrode body length L2 is preferably 1196 mm or less or 1190 mm or less, and the first electrode body length L2/second electrode body length H2 is preferably 8.8 or less or 8 or less. preferable. That is, the first electrode body length L2 (the first length of the electrode body 130 in the X-axis direction (first direction)) is equal to the second electrode body length H2 (the second electrode body length H2 (the second length of the electrode body 130 in the Z-axis direction (second direction)). length) is preferably 8.8 times or less, or 8 times or less. From Tables 2 and 3, it is preferable that the composite material layer forming portion width C1 is 8.6 times or less, or 8 times or less, the length H2 of the second electrode body. As shown in Table 3, the composite material layer forming portion width C1 is preferably 1170 mm or less or 1166 mm or less, and the composite material layer forming portion width C1/the composite material layer non-forming portion width C2 or C3 is 82 or less or 80 or less. is preferred. That is, the composite material layer forming portion width C1 (the width of the composite material layer forming portion 131 in the X-axis direction (first direction)) is equal to the composite material layer non-forming portion width C2 or C3 (the composite material layer non-forming portion 132 or 133 width) is preferably 82 times or less or 80 times or less. As shown in Table 4, it is preferable that the capacity of the storage element 100 is 267 Ah or less.

[4 Explanation of effects]
As described above, according to the energy storage device 100 according to the present embodiment, the electrode body 130 has the electrode plate wound around the winding axis R extending in the first direction (X-axis direction). Z-axis direction) is longer than the third direction (Y-axis direction). In the first direction, the width of the composite material layer forming portion C1 (the width of the composite material layer forming portion 131 of the electrode plate) is less than the width of the composite material layer non-forming portion C2 or C3 (the composite material at the end of the electrode plate in the first direction). 16 times or more of the width of the layer non-forming portion 132 or 133). In the electric storage element, when the electrode body is elongated in the horizontal direction, the space efficiency in the container 110 is reversed between the horizontally-wound electrode body and the vertically-wound electrode body, and the vertically-wound electrode body is the horizontally-wound electrode. It has a higher energy density than the body.

Specifically, as shown in FIG. 4 , in the horizontally wound electrode body, even if the electrode body 140 is elongated in the horizontal direction (X-axis direction), the poles in the vertical direction (Z-axis direction) in the container 110 are Since the proportion occupied by the composite material layer forming part 141 of the plate is generally constant, the proportion occupied by the composite material layer forming part 141 in the container 110 is substantially constant. On the other hand, as shown in FIG. 3, in the vertically wound electrode body, when the electrode body 130 is elongated in the horizontal direction (X-axis direction), the composite material layer non-formed portion 132 of the composite material layer formed portion 131 of the electrode plate becomes larger. , the proportion occupied by the composite material layer forming portion 131 in the container 110 is increased.

In the electrode body 130, the inventors of the present application found that when the composite material layer forming portion width C1 is 16 times or more of the composite material layer non-forming portion width C2 or C3, the vertically wound electrode body is larger than the horizontally wound electrode body. It was found that the energy density of the electric storage device 100 also increased. Therefore, the energy density of the storage element 100 can be improved by setting the composite material layer forming portion width C1 in the electrode body 130 to 16 times or more the composite material layer non-forming portion width C2 or C3.

The inventors of the present application have found that the energy density effectively increases until the width C1 of the electrode body 130 where the composite material layer is formed becomes 40 times or more the width of the composite material layer non-formed portion C2 or C3 in the electric storage device 100. I found out. Therefore, by setting the width C1 of the composite material layer formed portion of the electrode body 130 to be 40 times or more the width C2 or C3 of the composite material layer non-formed portion, the electrode body 130 with effectively increased energy density can be used. Therefore, the energy density of the storage element 100 can be improved.

The inventors of the present application have found that, in the electric storage device 100, if the width C1 of the electrode body 130 where the composite material layer is formed is greater than 80 times the width C2 or C3 of the composite material layer non-formed part, the electrode body 130 becomes too long and cannot be formed. Although difficult, it was found that the energy density did not increase significantly. Therefore, by setting the width C1 of the composite material layer forming portion of the electrode body 130 to 80 times or less of the width C2 or C3 of the composite material layer non-forming portion, the electrode body 130 can be easily formed and the energy density of the storage element 100 can be improved. can be improved.

The inventors of the present application found that in the electric storage element 100, the first electrode body length L2 (first length) in the first direction (X-axis direction) of the electrode body 130 is equal to the second electrode body length in the second direction (Z-axis direction). It was found that the vertically wound electrode body has a higher energy density than the horizontally wound electrode body when the height H2 (second length) is twice or more. Therefore, by making the first electrode body length L2 in the first direction of the electrode body 130 twice or more the second electrode body length H2 in the second direction, the energy density of the storage element 100 can be improved.

The inventor of the present application found that the energy density is effective until the first electrode body length L2 (first length) of the electrode body 130 becomes five times the second electrode body length H2 (second length) in the storage element 100. I found that it was getting higher. Therefore, by setting the first electrode body length L2 of the electrode body 130 to be at least five times the second electrode body length H2, the electrode body 130 with effectively increased energy density can be used. can improve the energy density of

The inventors of the present application have found that the energy density effectively increases when the width C1 of the composite material layer forming portion of the electrode assembly 130 is as long as 567 mm or more. Therefore, by increasing the width C1 of the composite material layer forming portion of the electrode body 130 to 567 mm or more, the electrode body 130 with effectively increased energy density can be used. can be planned.

In the electric storage element 100, the electrode terminals 120 protrude from the container 110, creating a space around the electrode terminals 120 that is difficult to utilize. If this space is large, the energy density of the entire power storage element 100 including the space will decrease. Therefore, in the electric storage element 100, the electrode terminals 120 protrude in the first direction from the end surface (the terminal arrangement surface 113) of the container 110 in the first direction (X-axis direction). As a result, the electrode terminal 120 protrudes from the small area of the outer surface of the container 110, and the space around the electrode terminal 120 that is difficult to utilize due to the protruding electrode terminal 120 can be reduced. Therefore, the energy density of the storage element 100 can be improved.

According to the power storage device 10 according to the present embodiment, since the power storage device 100 described above is provided, the energy density can be improved. In the power storage device 10, if the length of the power storage element 100 is long, the distance between the two electrode terminals 120 connected to the pair of external terminals 300 may increase. In this case, if the pair of external terminals 300 are arranged near the two electrode terminals 120, the pair of external terminals 300 are arranged at distant positions, which may make it difficult to connect the power storage device 10 to the outside. . However, when the pair of external terminals 300 are arranged close to each other, the length of the bus bar connecting the pair of external terminals 300 and the two electrode terminals 120 becomes long. Therefore, the pair of external terminals 300 is divided into the first electrode terminal 122 of the pair of first electrode terminals 120 of the first storage element 101 that is closer to the second storage element 102 and the pair of external terminals 120 that the second storage element 102 has. and the second electrode terminal 121 close to the first storage element 101 among the second electrode terminals 120 . As a result, in the power storage device 10 including the power storage element 100 capable of improving the energy density, an increase in the length of the bus bar connecting the external terminal 300 and the electrode terminal 120 of the power storage element 100 can be suppressed. , the pair of external terminals 300 can be arranged close to each other.

For example, in a power storage element having a columnar (cylindrical) electrode body, the current collector (or electrode terminal) is joined to the end face (the end face in the X-axis direction in FIG. 2) of the composite material layer non-formed portion of the electrode body. It is common to However, in this case, since the bonding area at the end face is small, the junction may melt when the storage element is charged and discharged with a large current due to an increase in the capacity of the storage element. In contrast, in the present embodiment, the current collector (or the electrode terminal 120) is joined to the flat portions (end flat portions 132a and 133a) of the electrode body 130, so that the joint area of the joint portion can be increased. . As a result, melting of the junction can be suppressed even when the storage device 100 is charged and discharged with a large current.

[5 Description of Modifications]
(Modification 1)
Next, Modification 1 of the above embodiment will be described. FIG. 6 is a front view showing the configuration of electrode body 130A according to Modification 1 of the present embodiment. Specifically, FIG. 6 is a diagram corresponding to FIG.

As shown in FIG. 6, an electrode body 130A in this modification has a composite material layer non-formed part 132c and a composite material layer non-formed part 132c and a 133c. Other configurations of this modified example are the same as those of the above-described embodiment, so detailed description thereof will be omitted.

The composite material layer

non-forming portions

132c and 133c are tabs on which a composite material layer is not formed and which are arranged at the end portion in the X-axis direction (first direction) of the composite material layer forming portion 131. That is, the composite material layer non-forming portion 132c is a rectangular flat tab parallel to the XZ plane that protrudes from the end of the composite material layer forming portion 131 in the positive X-axis direction in the positive X-axis direction. The composite material layer non-forming portion 133c is a rectangular and flat tab parallel to the XZ plane that protrudes in the negative X-axis direction from the end of the composite material layer-forming portion 131 in the negative X-axis direction. The current collector (or electrode terminal 120) is connected (bonded) to the flat non-composite

material layer portions

132c and 133c.

As described above, according to the power storage element according to this modified example, the same effects as those of the above-described embodiment can be obtained. That is, even in this modification, each size (L2, H2, W2, C1, C2, C3, etc.) of the electrode body 130A is the same as that of the electrode body 130 in the above-described embodiment. I can say. Since the current collector (or the electrode terminal 120) is joined to the flat portion of the electrode body 130A, the same applies to the above embodiment.

(Modification 2)
Next, Modification 2 of the above embodiment will be described. FIG. 7 is a perspective view showing the configuration of a power storage element 100A according to Modification 2 of the present embodiment. Specifically, FIG. 7 is a diagram corresponding to the storage element 100 of FIG.

As shown in FIG. 7, a power storage element 100A in this modification includes electrode terminals 120A instead of the electrode terminals 120 included in the power storage element 100 in the above embodiment. The electrode terminals 120A are arranged in a state of protruding in the positive Z-axis direction from the end face (cover plate) of the container 110 in the positive Z-axis direction at both ends in the X-axis direction of the container 110 of the power storage element 100A. Other configurations of this modified example are the same as those of the above-described embodiment, so detailed description thereof will be omitted.

As described above, according to the power storage element 100A according to this modified example, the same effects as those of the above-described embodiment can be achieved. In this modification, in order to reduce the space around the electrode terminal 120A that is difficult to utilize, it is preferable that the height of the electrode terminal 120A projected in the Z-axis direction is low.

Thus, the arrangement position of the electrode terminals in the storage element is not particularly limited. The number of electrode terminals included in the storage element is not particularly limited, either. In the above embodiment, a pair of electrode terminals 120 may protrude from only one side of the container 110 in the X-axis direction, or two electrode terminals 120 may protrude from both sides of the container 110 in the X-axis direction. An electrode terminal 120 may protrude from the long side 111 of the container 110 .

(Other modifications)
As described above, the power storage element and the power storage device according to the embodiments of the present invention (including modifications thereof; the same applies hereinafter), but the present invention is not limited to the above embodiments. The embodiments disclosed this time are exemplifications in all respects, and the scope of the present invention includes all modifications within the meaning and scope of equivalents to the scope of the claims.

In the above embodiment, a plurality of rectangular parallelepiped power storage elements 100 (a plurality of first power storage elements 101 and a plurality of second power storage elements 102) are arranged. However, the shape of the storage element 100 (container 110) is not limited to a rectangular parallelepiped shape, and may be a polygonal columnar shape, an oval columnar shape, an elliptical shape, a circular shape, or the like other than the rectangular parallelepiped shape. The power storage elements 100 may be arranged in one row instead of two rows in the X-axis direction, or may be arranged in three or more rows. Only one power storage element 100 may be arranged in the Y-axis direction (only one first power storage element 101 and one second power storage element 102 may be arranged), and only one power storage element 100 may be arranged. It does not have to be placed.

In the above embodiment, all power storage elements 100 and all electrode bodies 130 have the above configuration. However, any storage element 100 may not have the above configuration, and any electrode assembly 130 may not have the above configuration.

A form constructed by arbitrarily combining each component provided in the above embodiment and its modifications is also included within the scope of the present invention.

The present invention can be applied to power storage elements such as lithium ion secondary batteries.

10

power storage device

100, 100A power storage element 101 first power storage element 102 second power storage element 110 container 111 long side 112 short side 113 terminal arrangement surface 120, 121, 122 electrode terminal (first electrode terminal, second electrode terminal)

120A electrode terminal

130, 130A, 140 electrode body 131, 141 composite material layer formed portion 131a composite material layer flat portion 131b composite material layer

curved portion

132, 132c, 133, 133c, 142 composite material layer non-formed portion 132a, 133a end

portion Flat portions

132b, 133b End curved portion 200 Exterior body 300 External terminal L1 First container length H1 Second container length W1 Third container length L2 First electrode length H2 Second electrode length W2 Third electrode length A Positive electrode plate width B Negative electrode plate width C1 Mixed material layer formed part width C2, C3, C4 Mixed material layer non-formed part width R, Rz Winding axis

Claims

A power storage element comprising an electrode body in which an electrode plate having a composite material layer formed thereon is wound around a winding axis extending in a first direction,
The electrode plate is
a composite material layer forming portion in which the composite material layer is formed;
a composite material layer non-forming portion disposed at an end portion in the first direction from the composite material layer forming portion and in which the composite material layer is not formed;
The electrode body has a flat shape in which the length in a second direction that intersects the first direction is longer than the length in a third direction that intersects the first direction and the second direction,
In the first direction, the width of the composite material layer forming portion is 16 times or more the width of the composite material layer non-forming portion.
The electric storage device according to claim 1, wherein the width of the composite material layer forming portion is 40 times or more the width of the composite material layer non-forming portion in the first direction.
The electric storage device according to claim 1 or 2, wherein the width of the composite material layer forming portion is 80 times or less the width of the composite material layer non-forming portion in the first direction.
The electric storage element according to any one of claims 1 to 3, wherein the first length in the first direction of the electrode body is twice or more the second length in the second direction of the electrode body.
The electric storage device according to claim 4, wherein the first length is five times or more the second length.
A power storage element comprising an electrode body in which an electrode plate having a composite material layer formed thereon is wound around a winding axis extending in a first direction,
The electrode plate is
a composite material layer forming portion in which the composite material layer is formed;
a composite material layer non-forming portion disposed at an end portion in the first direction from the composite material layer forming portion and in which the composite material layer is not formed;
The electrode body has a flat shape in which the length in a second direction that intersects the first direction is longer than the length in a third direction that intersects the first direction and the second direction,
A first length in the first direction of the electrode body is at least five times as long as a second length in the second direction of the electrode body.
The electric storage element according to any one of claims 1 to 6, wherein the width of the composite material layer forming portion in the first direction is 567 mm or more.
a container in which the electrode body is housed;
The electric storage element according to any one of claims 1 to 7, further comprising an electrode terminal projecting in the first direction from an end face of the container in the first direction.
a plurality of power storage elements according to any one of claims 1 to 8;
a pair of external terminals;
the plurality of energy storage elements have a first energy storage element and a second energy storage element arranged in the first direction,
The first storage element has a pair of first electrode terminals arranged in the first direction,
The second storage element has a pair of second electrode terminals arranged in the first direction,
The pair of external terminals includes a first electrode terminal of the pair of first electrode terminals that is closer to the second storage element and a second electrode that is of the pair of second electrode terminals and is closer to the first storage element. A power storage device connected to a terminal.