WO2024150803A1

WO2024150803A1 - Power storage element and method for producing same

Info

Publication number: WO2024150803A1
Application number: PCT/JP2024/000531
Authority: WO
Inventors: 祐介小川; 広徳相田; 良一奥山
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2023-01-13
Filing date: 2024-01-12
Publication date: 2024-07-18

Abstract

This power storage element (10) is provided with: an electrode body (700) which has stacked electrode plates, while comprising a connection part (720); a collector (600) which is electrically connected to the connection part (720); a container (100) which houses the electrode body (700) and the collector (600); and a terminal (300) which is fitted to the container (100) and is electrically connected to the collector (600). The container (100) is provided with a container main body (160) and a container cover member (170) which is bonded to the container main body (160). The container main body (160) is provided with: a bottom wall (161) that is disposed in the stacking direction of the electrode plates; and a side wall (162) that is provided so as to extend upwardly from at least a part of the peripheral edge of the bottom wall (161). The collector (600) is provided with a terminal connection part (640) and an electrode body connection part (630). The terminal connection part (640) is bonded to the terminal (300), while the electrode body connection part (630) is bonded to the connection part (720).

Description

Electric storage element and manufacturing method thereof

The present invention relates to an energy storage element and a method for manufacturing the same.

　Conventionally, a flat wound secondary battery is known that includes a wound group and a cylindrical battery can that houses the wound group. During manufacture, the wound group is inserted into the open end of the flat cylindrical battery can and housed therein (see Patent Document 1).

JP 2013-161555 A

When inserting the battery, friction and pressure from the battery can on the wound group can cause damage to the electrodes.

The present invention therefore aims to provide an energy storage element and a manufacturing method thereof that can suppress damage to the electrode body during manufacturing.

The energy storage element according to one aspect of the present invention comprises an electrode body having stacked plates including a connection portion, a current collector electrically connected to the connection portion of the electrode body, a container that houses the electrode body and the current collector, and a terminal attached to the container and electrically connected to the current collector, the container comprises a container body and a container lid body joined to the container body, the container body has a bottom wall arranged in the stacking direction of the electrode plates and a side wall that is provided in a state rising from at least a part of the periphery of the bottom wall, the current collector comprises a terminal connection portion and an electrode body connection portion, the terminal connection portion is joined to the terminal, and the electrode body connection portion is joined to the connection portion.

The energy storage element of the present invention can suppress damage to the electrode body during manufacturing.

FIG. 1 is a perspective view showing the appearance of an energy storage device according to an embodiment. FIG. 2 is an exploded perspective view showing the components of the energy storage device according to the embodiment. FIG. 3 is a cross-sectional view showing a connection structure between a terminal and a current collector according to the embodiment. FIG. 4 is a perspective view showing the configuration of an electrode body according to an embodiment. FIG. 5 is an explanatory diagram showing a method for manufacturing an energy storage element according to an embodiment. FIG. 6 is an explanatory diagram showing a manufacturing method of an energy storage element according to the first modification. FIG. 7 is an explanatory diagram showing a manufacturing method of an energy storage element according to the second modification. FIG. 8 is an explanatory diagram showing an energy storage device including the energy storage element according to the embodiment.

(1) An energy storage element according to one aspect of the present invention comprises an electrode body having stacked plates including a connection portion, a current collector electrically connected to the connection portion of the electrode body, a container that houses the electrode body and the current collector, and a terminal attached to the container and electrically connected to the current collector, the container comprises a container body and a container lid that is joined to the container body, the container body has a bottom wall that is arranged in the stacking direction of the electrode plates and a side wall that is provided in a state that rises from at least a part of the periphery of the bottom wall, the current collector comprises a terminal connection portion and an electrode body connection portion, the terminal connection portion is joined to the terminal, and the electrode body connection portion is joined to the connection portion.

When manufacturing such an energy storage element, the friction that the electrode body experiences from the container body when inserting the electrode body into the container can be reduced. In other words, damage to the electrode body during manufacturing can be suppressed.

(2) In the energy storage element described in (1) above, the side walls may be provided in a state where they rise from the entire periphery of the bottom wall.

This allows the friction that the electrode body receives from the container body during manufacturing to be reduced, even in a container body whose side walls rise from the entire periphery of the bottom wall. Therefore, even in such a container body, damage to the electrode body during manufacturing can be suppressed.

(3) In the energy storage element described in (1) or (2) above, the electrodes are stacked in a first direction, the electrode body has a main body portion in which an active material layer is formed, the connection portion protrudes from the main body portion at both ends in a second direction intersecting with the first direction, and the electrode body connection portion may be aligned along a third direction intersecting with the first direction and the second direction.

This allows the electrode body connection part of the current collector to be joined to the electrode body connection part along the third direction without being restricted by the main body of the electrode body. This increases the degree of freedom when designing the joint area and joint position.

(4) In the energy storage element described in any one of (1) to (3) above, the container may have a rectangular shape in a plan view of the bottom wall with the corners cut out, and the terminal may be attached to the side wall in the cut-out portion.

With this, since the terminal is attached to the side wall of the cut-out portion, the portion (active material layer forming portion) that contributes to the power generation (electricity storage) of the electrode body can be placed in a position adjacent to the cut-out portion inside the container. This makes it possible to reduce excess space inside the container and increase the energy density of the electricity storage element.

(5) In the energy storage element described in any one of (1) to (4) above, the electrode body connection portion may be disposed on the side of the electrode body opposite the bottom wall.

This is advantageous because the other end of the current collector is positioned on the opposite side of the bottom wall of the electrode body, allowing the current collector to be deformed as intended during manufacturing.

A manufacturing method for an energy storage element according to another aspect of the present invention is a manufacturing method for an energy storage element including an electrode body having stacked electrode plates including a connection portion, a current collector electrically connected to the connection portion, a container that houses the electrode body and the current collector, and a terminal attached to the container and electrically connected to the current collector, the container including a container body and a container lid body joined to the container body, the container body having a bottom wall and a side wall that is provided in a state rising from at least a part of the periphery of the bottom wall, the manufacturing method includes joining one end of the current collector to the terminal and joining the other end of the current collector to the connection portion, and then deforming the current collector between the one end and the other end.

In this way, after joining one end of the current collector to the terminal and the other end of the current collector to the connection part, the current collector is deformed between the one end and the other end. This deformation causes the electrode body to be tilted onto the bottom wall. In this way, during manufacturing, the electrode body is simply tilted onto the bottom wall, so friction that the electrode body experiences from the container body can be reduced. In other words, damage to the electrode body during manufacturing can be suppressed.

(Embodiment)
Hereinafter, with reference to the drawings, a description will be given of an energy storage element according to an embodiment (including its modified example) of the present invention. The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection forms of the components, the manufacturing process, and the order of the manufacturing process shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, the dimensions are not strictly illustrated. In each figure, the same or similar components are given the same reference numerals. The names of the components (each component) in this embodiment are those in this embodiment and may differ from the names of the components (each component) in the background art.

In the following explanation and drawings, the direction in which the short sides of the container face each other is defined as the X-axis direction. The direction in which the long sides of the container face each other, the direction in which the container body and container lid are aligned, or the thickness direction of the container is defined as the Y-axis direction. The direction in which the top and bottom surfaces of the container are aligned, or the up-down direction, is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect with each other (orthogonal in this embodiment). Depending on the mode of use, it is possible that the Z-axis direction is not the up-down direction, but for ease of explanation, the following explanation will be given assuming that the Z-axis direction is the up-down direction.

In the following explanation, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the opposite direction to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. Hereinafter, the Y-axis direction may also be called the first direction, the X-axis direction may also be called the second direction, and the Z-axis direction may also be called the third direction. Expressions indicating relative directions or attitudes, such as parallel and orthogonal, may also include cases where the direction or attitude is not strictly speaking the same. Two directions being orthogonal does not only mean that the two directions are completely orthogonal, but also means that they are substantially orthogonal, that is, there is a difference of about a few percent. In the following explanation, when the word "insulation" is used, it means "electrical insulation".

[General Description of Energy Storage Element]
First, an overall description of an energy storage device 10 according to the present embodiment will be given with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the external appearance of the energy storage device 10 according to the embodiment. Fig. 2 is an exploded perspective view showing each component of the energy storage device 10 according to the embodiment.

The energy storage element 10 is an energy storage element that can be charged with electricity from the outside and can discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. The energy storage element 10 is a battery used for power storage or power supply purposes. Specifically, the energy storage element 10 is used as a battery for driving or starting the engine of a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV), or a railway vehicle for an electric railway. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of the above-mentioned railway vehicles for an electric railway include electric trains, monorails, linear motor cars, and hybrid electric trains equipped with both a diesel engine and an electric motor. The energy storage element 10 may be used as a stationary battery for home or business use.

The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may be a primary battery instead of a secondary battery. The energy storage element 10 may be a battery using a solid electrolyte. The energy storage element 10 may be a pouch-type energy storage element. In this embodiment, the energy storage element 10 based on a flat rectangular parallelepiped shape (approximately rectangular parallelepiped shape) is illustrated, but the shape of the energy storage element 10, i.e., the shape of the container 100, is not limited to a shape based on a rectangular parallelepiped shape, and may be a shape based on a polygonal prism shape other than a rectangular parallelepiped, an elongated cylinder shape, an elliptical cylinder shape, a cylindrical shape, or a cylindrical shape.

As shown in Figures 1 and 2, the energy storage element 10 comprises a container 100, a pair of terminals 300, and a pair of external gaskets 400. A pair of internal gaskets 500, a pair of current collectors 600, and an electrode body 700 are housed inside the container 100. Specifically, the positive electrode components (one terminal 300, one external gasket 400, one internal gasket 500, one current collector 600, etc., the same below) are arranged at one end of the container 100 in the positive direction of the X axis. The negative electrode components are arranged at the other end of the container 100 in the negative direction of the X axis.

An electrolyte (non-aqueous electrolyte) is enclosed inside the container 100, but is not shown in the figure. There is no particular limit to the type of electrolyte as long as it does not impair the performance of the energy storage element 10, and various electrolytes may be selected. In addition to the above components, spacers may be placed on the sides, above, or below the electrode body 700, and insulating films may be placed to insulate the electrode body 700 and the current collector 600 from the container 100.

The container 100 is a case having an outer shape (approximately rectangular parallelepiped shape) based on a flat rectangular parallelepiped shape that is long in the X-axis direction. The length of the container 100 in the X-axis direction is three times or more than the length of the container 100 in the Z-axis direction. The length of the container 100 in the X-axis direction is five times or more than the length of the container 100 in the Y-axis direction. In FIG. 1, the rectangular parallelepiped shape that serves as the reference is illustrated by a two-dot chain line L1. Specifically, a pair of rectangular cutouts 101 are formed at the top of both ends of the container 100 in the X-axis direction. As a result, the container 100 has a shape with a pair of cutouts 101 in which a pair of adjacent corners of a rectangle (including a square) are cut out when viewed in the Y-axis direction. The pair of cutouts 101 are lined up in the X-axis direction. Of the pair of cutouts 101, the cutout 101 in the positive direction of the X-axis is referred to as the first cutout 110, and the cutout 101 in the negative direction of the X-axis is referred to as the second cutout 120.

Specifically, the first notch 110 is formed by a rectangular first side surface 111 parallel to the YZ plane, and a rectangular first upper surface 112 extending from the lower end of the first side surface 111 in the positive direction of the X axis and parallel to the XY plane. The first notch 110 is a corner of the container 100 in the positive direction of the X axis and the positive direction of the Z axis that is missing in a square shape (L-shape) when viewed from the Y axis direction.

The second cutout 120 is formed by a rectangular second side surface 121 parallel to the YZ plane, and a rectangular second upper surface 122 extending from the lower end of the second side surface 121 in the negative X-axis direction and parallel to the XY plane. The second cutout 120 is a recess in which the corner of the container 100 in the negative X-axis direction and the positive Z-axis direction is recessed into a square shape (L-shape) when viewed from the Y-axis direction.

In the container 100, the long sides 130 are opposite end faces in the Y-axis direction. Each long side 130 is a flat surface parallel to the XZ plane and elongated in the X-axis direction, and both ends in the X-axis direction have a shape corresponding to each notch 101.

In the container 100, the

short sides

113, 123 are the surfaces at both ends that face each other in the X-axis direction. The short side 113 has an upper end that is continuous with the first upper surface 112 and is a rectangular flat surface parallel to the YZ plane. The short side 123 has an upper end that is continuous with the second upper surface 122 and is a rectangular flat surface parallel to the YZ plane.

Of the two end faces of container 100 that face each other in the Z-axis direction, the end face facing the positive Z-axis direction is upper face 140, and the end face facing the negative Z-axis direction is lower face 150. Upper face 140 is a plane that connects the upper end of first side face 111 and the upper end of second side face 121, and is a rectangular plane parallel to the XY plane. Lower face 150 is a plane that connects the lower end of short side face 113 and the lower end of short side face 123, and is a rectangular plane parallel to the XY plane.

The container 100 has a container body 160 and a container lid 170. The container 100 has a roughly rectangular parallelepiped shape with the container body 160 and the container lid 170 assembled together. The container body 160 has a long side 130 in the positive Y-axis direction, an upper surface 140, a lower surface 150,

short sides

113, 123, a first side surface 111, a first upper surface 112, a second side surface 121, and a second upper surface 122.

The container body 160 has a shape in which one of a pair of long side walls of a substantially rectangular parallelepiped has been removed. In other words, the container body 160 is a box with an opening in which one wall in the thickness direction (negative Y-axis direction) of a substantially rectangular parallelepiped having a short side wall and a long side wall is opened. The container body 160 has a flat bottom wall 161 and a side wall 162 rising in the negative Y-axis direction from the entire circumference of the bottom wall 161. The side wall 162 is formed by an upper surface 140, a lower surface 150, short side surfaces 113, 123, a first side surface 111, a first upper surface 112, a second side surface 121, and a second upper surface 122. The side wall 162 forms an opening in which the electrode body 700 and the like are housed. One of a pair of long side surfaces 130 of the container 100 is included in the bottom wall 161.

The length between the short side surface 113 of the side wall 162 and the short side surface 123 of the side wall 162 in the container body 160 is three times or more the length between the upper surface 140 of the side wall 162 and the lower surface 150 of the side wall 162 in the container 160. In other words, the length of the long side of the bottom wall 161 (the length of the side in the X-axis direction) when viewed from the stacking direction of the electrode plates (Y-axis direction, first direction) is three times or more the length of the short side of the bottom wall 161 (the length of the side in the Z-axis direction). The length between the short side surface 113 of the side wall 162 and the short side surface 123 of the side wall 162 in the container body 160 is five times or more the height of the side wall 162. In other words, the length of the long side of the bottom wall 161 (the length of the side in the X-axis direction) is five times or more the height of the side wall 162 (the length of the side in the Y-axis direction).

The container lid 170 covers the opening formed by the side wall 162 of the container body 160. The container lid 170 is joined to the side wall 162. The other of the pair of long sides 130 of the container 100 is included in the container lid 170. Therefore, the pair of long sides 130 of the container 100 are the surface of the bottom wall 161 and the surface of the container lid 170. With this configuration, the container 100 is sealed by accommodating the electrode body 700 and the like in the opening of the container body 160, and then joining the container body 160 and the container lid 170 by welding or the like. The material of the container 100 (container body 160 and container lid 170) is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

The container body 160 is formed with a liquid injection section 168 and a gas exhaust valve 169. The gas exhaust valve 169 is a safety valve that releases pressure when the pressure inside the container 100 rises excessively. The liquid injection section 168 is a section for injecting electrolyte into the container 100 during the manufacture of the energy storage element 10.

The terminals 300 are terminals (positive electrode terminal 310 and negative electrode terminal 320) that are electrically connected to the electrode body 700 via the current collector 600. In other words, the terminals 300 are metal members that lead out the electricity stored in the electrode body 700 to the external space of the energy storage element 10 and introduce electricity into the internal space of the energy storage element 10 to store electricity in the electrode body 700. The material of the terminals 300 is not particularly limited, but the terminals 300 are formed of a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy. The terminals 300 are connected (joined) to the current collector 600 by crimping, welding, or the like, and are attached to the container body 160.

FIG. 3 is a cross-sectional view showing the connection structure between the terminal 300 according to the embodiment and the current collector 600, etc. FIG. 3 is a cross-sectional view of a cut surface including the line III-III shown in FIG. 1. FIG. 3 shows the connection structure of each component of the positive electrode, but the connection structure of each component of the negative electrode is basically the same.

As shown in FIG. 3, the terminal 300 has a terminal body 330 and a shaft 340 protruding from the terminal body 330. The terminal body 330 is a portion disposed outward from the terminal installation surface of the container 100. The terminal 300 (terminal body 330) protrudes from the terminal installation surface of the container 100 in the Z-axis direction (third direction). The terminal installation surface in this embodiment is the first upper surface 112 and the second upper surface 122. The terminal installation surface is a surface on which the terminal body 330 is installed via the external gasket 400. At the locations corresponding to each terminal installation surface, through holes 112a, 122a through which the shaft 340 penetrates are formed. The shaft 340 is connected (joined) to the current collector 600 by being crimped in a state in which it penetrates the terminal installation surface, the external gasket 400, the internal gasket 500, and the current collector 600.

The current collectors 600 are arranged at both ends of the electrode body 700 in the X-axis direction (the positive end and the negative end in the second direction). The current collectors 600 are connected (joined) to the electrode body 700 and the terminal 300, and are conductive members (positive electrode current collector 610 and negative electrode current collector 620) that electrically connect the electrode body 700 and the terminal 300. There are no particular limitations on the material of the current collectors 600, but the positive electrode current collector 610 is formed of a conductive member such as aluminum or an aluminum alloy, and the negative electrode current collector 620 is formed of a conductive member such as copper or a copper alloy.

Specifically, the current collector 600 is formed by bending a plate-like member. The current collector 600 has an electrode body connection part 630 and a terminal connection part 640. The electrode body connection part 630 is a flat part that is connected (joined) to a connection part 720 of the electrode body 700 described later by welding, crimping, or the like. The electrode body connection part 630 is disposed on the opposite side of the connection part 720 from the bottom wall 161. The electrode body connection part 630 is connected to the connection part 720 in a position along the bottom wall 161. The thickness of the folded part of the current collector 600 may be made thinner than the thickness of the other parts of the current collector 600. By making the folded part of the current collector 600 thinner, it can be easily folded.

The terminal connection portion 640 is a flat portion that is connected (joined) to the terminal 300 by crimping or welding. Specifically, the terminal connection portion 640 has a through hole 641, and the shaft portion 340 of the terminal 300 is crimped and joined through this through hole 641. The terminal connection portion 640 is connected to the shaft portion 340 in a position that is aligned with the side wall 162.

The external gasket 400 is a plate-shaped, rectangular insulating sealing member that is disposed between the container body 160 and the terminal 300 of the container 100, and insulates and seals between the container body 160 and the terminal 300. The internal gasket 500 is a plate-shaped, rectangular insulating sealing member that is disposed between the container body 160 and the current collector 600, and insulates and seals between the container body 160 and the current collector 600. The external gasket 400 and the internal gasket 500 are formed from electrically insulating resins such as polypropylene (PP), polyethylene (PE), polystyrene (PS), ABS resin, or composite materials thereof.

The electrode body 700 is an electricity storage element (power generating element) formed by winding an electrode plate. As shown in FIG. 2, the electrode body 700 is arranged with the winding axis L oriented along the X-axis direction. The electrode body 700 has an elongated shape extending in the X-axis direction, and has an elliptical shape when viewed from the X-axis direction. In this embodiment, the X-axis direction is the direction in which a pair of

short sides

113, 123 of the container 100 face each other. The electrode body 700 has a shape that extends in the X-axis direction (second direction) to a length of 300 mm or more, specifically, to about 500 mm to 1500 mm. For this reason, the electrode body 700 has a length in the X-axis direction that is longer than the length in the Z-axis direction (third direction). The electrode body 700 has a length in the X-axis direction that is three times or more longer than the length in the Z-axis direction. The electrode body 700 has a main body 710 and two connection parts 720 that protrude from the main body 710 to both ends in the X-axis direction (the positive end and the negative end in the second direction). As described above, the connection parts 720 are connected (joined) to the current collector 600. The direction in which the connection parts 720 protrude from the main body 710 is along the axis (winding axis L) about which the electrode plate is wound.

Specifically, the two connection parts 720 protrude from both end faces of the main body 710 in the X-axis direction, one each. A positive electrode connection part 721 is provided on one end face of the main body 710 in the positive X-axis direction, at a predetermined distance from the end face in the positive Z-axis direction. On the other hand, a negative electrode connection part 722 is provided on the other end face of the main body 710 in the negative X-axis direction, at a predetermined distance from the end face in the positive Z-axis direction. As shown in FIG. 2, the electrode body 700 has a rectangular shape with corners cut out in a plan view of the flat part 712 described below. The cut-out parts correspond to the parts with the predetermined distance. Therefore, the electrode body 700 has a protrusion on the positive side in the Z-axis direction. The configuration of such an electrode body 700 will be described in detail below.

[Explanation of the configuration of the electrode body]
Fig. 4 is a perspective view showing the configuration of an electrode assembly 700 according to an embodiment. Specifically, Fig. 4 shows the configuration in a partially developed state in which the electrode plates in the electrode assembly 700 are wound. As shown in Fig. 4, the electrode assembly 700 has a positive electrode plate 740, a negative electrode plate 750, and

separators

761 and 762.

The positive electrode plate 740 is an electrode plate in which a positive electrode active material layer 742 is formed on the surface of a positive electrode current collector foil 741, which is a strip-shaped metal foil. Aluminum or an aluminum alloy, etc. is used for the positive electrode current collector foil 741. The negative electrode plate 750 is an electrode plate in which a negative electrode active material layer 752 is formed on the surface of a negative electrode current collector foil 751, which is a strip-shaped metal foil. Copper or a copper alloy, etc. is used for the negative electrode current collector foil 751. As the positive electrode active material used in the positive electrode active material layer 742 and the negative electrode active material used in the negative electrode active material layer 752, any suitable known material can be used as long as it is a positive electrode active material and a negative electrode active material that can absorb and release lithium ions.

As the positive electrode active material, polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , and LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, spinel-type lithium manganese oxides such as LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ , and lithium transition metal oxides such as LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) may be used. As the negative electrode active material, lithium metal, an alloy capable of absorbing and releasing lithium, a carbon material (graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature baked carbon, amorphous carbon, etc.), silicon oxide, etc. may be used.

Separators

761 and 762 are microporous sheets made of resin. Any known material can be used as the material for

separators

761 and 762 as long as it does not impair the performance of energy storage element 10.

Separators

761 and 762 may be made of woven fabric or nonwoven fabric that is insoluble in organic solvents, or a synthetic resin microporous film made of a polyolefin resin such as polyethylene.

The electrode body 700 is formed by winding the positive electrode plate 740, the negative electrode plate 750, and the

separators

761 and 762. That is, the electrode body 700 is formed by stacking the negative electrode plate 750, the separator 761, the positive electrode plate 740, and the separator 762 in this order and winding them. In this embodiment, the positive electrode plate 740, the negative electrode plate 750, etc. are wound around the winding axis L extending in the X-axis direction to form the wound electrode body 700. The winding axis L is a virtual axis that serves as the central axis when winding the positive electrode plate 740, the negative electrode plate 750, etc. In this embodiment, the winding axis L is a straight line that passes through the center of the electrode body 700 and is parallel to the X-axis direction. The electrode body 700 is arranged in the container 100 with the winding axis L oriented along the direction in which the short side surfaces 113 and 123 of the container 100 face each other (second direction).

Multiple protruding pieces 743 are spaced apart on one edge of the positive electrode plate 740 in the winding axis direction (the edge in the positive direction of the X-axis). Similarly, multiple protruding pieces 753 are spaced apart on the other edge of the negative electrode plate 750 in the winding axis direction (the edge in the negative direction of the X-axis). Protruding

pieces

743 and 753 are portions where no active material layer containing active material is formed and where the metal foil (current collector foil) is exposed (active material layer non-formed portions). The shaded areas in Figure 4 correspond to the active material layer non-formed portions.

When the positive electrode plate 740 and the negative electrode plate 750 and the

separators

761, 762 are wound, the protruding pieces 743 of the positive electrode plate 740 overlap on one end surface of the main body 710. The portion where the protruding pieces 743 of the positive electrode plate 740 overlap is the positive electrode connection portion 721. Similarly, the protruding pieces 753 of the negative electrode plate 750 overlap on the other end surface of the main body 710. The portion where the protruding pieces 753 of the negative electrode plate 750 overlap is the negative electrode connection portion 722.

The main body 710 is an elongated cylindrical portion (active material layer forming portion) formed by winding a portion where the positive electrode active material layer 742 is formed (coated), a portion where the negative electrode active material layer 752 is formed (coated), and

separators

761, 762. The main body 710 has a pair of curved portions 711 on both sides in the Z-axis direction, and a flat portion 712 between the pair of curved portions 711. It can also be said that the pair of curved portions 711 are positioned to sandwich the flat portion 712 in the Z-axis direction.

The curved portions 711 are curved portions in which the arc shape of the end portion in the Z-axis direction extends in the X-axis direction when viewed from the X-axis direction. The curved portions 711 face the upper surface 140 and the lower surface 150, which are part of the side wall 162 of the container body 160. In other words, the pair of curved portions 711 are curved portions that protrude from the flat portions 712 on both sides in the Z-axis direction when viewed from the X-axis direction.

The flat portion 712 is a rectangular, flat portion extending parallel to the XZ plane, connecting the ends of the pair of curved portions 711. The flat portion 712 faces the bottom wall 161 of the container body 160 and the container lid 170. In the flat portion 712, a plurality of wound electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked in the Y-axis direction (first direction). In other words, in the flat portion 712, the Y-axis direction (first direction) is the stacking direction of the plurality of electrode plates. In this embodiment, the electrode body 700 is accommodated in the container 100 so that the stacking direction of the electrode plates in the flat portion 712 of the electrode body 700 is the Y-axis direction (first direction). The bottom wall 161 of the container body 160 is arranged on one side of the stacking direction (positive Y-axis direction) of the electrode body 700, and the container lid 170 is arranged on the other side of the stacking direction (negative Y-axis direction).

The curved shape of the curved portion 711 is not limited to a semicircular arc shape, but may be a part of an ellipse, etc., and may be curved in any manner. The outer surface of the flat portion 712 facing the Y-axis direction is not limited to being flat, but the outer surface may be slightly concave or slightly bulging.

[Method of manufacturing the energy storage element]
Next, a method for manufacturing the energy storage element 10 will be described. Fig. 5 is an explanatory diagram showing a method for manufacturing the energy storage element 10 according to the embodiment. In Fig. 5, the steps proceed in the order of (a), (b), and (c). Fig. 5 shows a connection structure of each member of the positive electrode of the energy storage element 10, but the same is true for the connection structure of each member of the negative electrode. An example is shown in which a manufacturing device performs each step, but an operator may also perform each step.

As shown in FIG. 5A, first, the manufacturing device crimps and joins the flat collector 600 to the shaft 340 of the terminal 300 with the external gasket 400, internal gasket 500, and terminal 300 placed in the cutout 101 (terminal installation surface) of the container body 160. Specifically, one end (terminal connection portion 640) of the collector 600 is joined to the shaft 340 of the terminal 300 in a position along the side wall 162 of the container body 160. As a result, the collector 600 is raised up against the bottom wall 161 of the container body 160. In this state, the manufacturing device joins the connection portion 720 of the electrode body 700 to the other end (electrode body connection portion 630) of the collector 600. As a result, the electrode body 700 is raised up against the bottom wall 161 of the container body 160. Specifically, the flat portion 712 of the electrode body 700 rises up along the first direction. When the current collector 600 rises up against the bottom wall 161, the current collector 600 does not need to be at a right angle to the bottom wall 161. It is sufficient that the electrode body 700 is raised at an angle that does not interfere with the bottom wall 161 during the operation of joining the current collector 600 and the electrode body 700.

5B, the manufacturing device tilts the other end of the current collector 600 until the other end is aligned with the bottom wall 161, thereby bending and deforming the portion between one end and the other end of the current collector 600. Specifically, the current collector 600 is bent at the periphery of the tip (crimped portion) of the shaft portion 340 of the terminal 300. This bent portion is referred to as the bent portion 650. The bent portion 650 is formed along the X-axis direction. The bent portion 650 is aligned with the direction in which the connection portion 720 protrudes from the main body portion 710 (second direction). As a result, the electrode body 700 is tilted from a position along the Y-axis direction (first direction) to a position along the Z-axis direction (third direction) and is accommodated in the container main body 160 in a position along the bottom wall 161. The electrode body 700 is tilted with the bent portion 650 as a reference. When the electrode body 700 is aligned along the bottom wall 161, the end of the body 710 in the positive Z-axis direction is positioned between a pair of notches 101 in the container body 160 (see FIG. 5(c)).

Then, as shown in FIG. 5(c), the manufacturing device closes the opening formed by the side wall 162 of the container body 160 with the container lid 170 and joins the container lid 170 to the side wall 162.

[Effects]
As described above, according to the embodiment of the present invention, during manufacturing, one end (terminal connection portion 640) of the current collector 600 is connected to the terminal 300, and the current collector 600 is arranged so as to rise up against the bottom wall 161. After that, the connection portion 720 of the electrode body 700 is joined to the other end (electrode body connection portion 630) of the current collector 600, and then the area between one end and the other end of the current collector 600 is deformed until the other end is in a position along the bottom wall 161. As a result, the other end of the current collector 600 and the electrode body 700 are tilted, and the electrode body 700 is housed in the container body 160 in a position along the bottom wall 161. In the state after manufacturing, the terminal connection portion 640 of the current collector 600 is joined to the terminal 300 in a position facing the side wall 162, and the electrode body connection portion 630 is bent with respect to the terminal connection portion 640 and in a position along the bottom wall 161. During the manufacture of such an energy storage element 10, the electrode body 700 is simply inverted on the bottom wall 161, so that the friction that the electrode body 700 receives from the container body 160 can be reduced. In other words, damage to the electrode body 700 during manufacture can be suppressed. This embodiment differs from the method of inserting the electrode body into the container from an opening in the short side wall of a rectangular container. In this embodiment, the electrode body 700 is inserted into the container from an opening in the long side wall of a rectangular container. Since the electrode body 700 is inserted from an opening in the long side wall, which has a larger area than the short side wall, damage to the electrode body 700 can be suppressed.

Even in a container body 160 in which the side wall 162 rises from the entire periphery of the bottom wall 161, the friction that the electrode body 700 experiences from the container body 160 during manufacturing can be reduced. Therefore, even in such a container body 160, damage to the electrode body 700 during manufacturing can be suppressed.

The electrodes (positive electrode plate 740, negative electrode plate 750) of the energy storage element 10 are stacked in the Y-axis direction (first direction). The electrode body 700 has a main body 710 on which an active material layer is formed, and the connection portion 720 protrudes from the main body 710 at both ends (positive end and negative end in the second direction) in the X-axis direction intersecting with the Y-axis direction. The electrode body connection portion 630 of the current collector 600 is along the Z-axis direction (third direction) intersecting with the Y-axis direction and the X-axis direction. Therefore, the length of the electrode body connection portion 630 in the Z-axis direction is not limited by the main body 710 of the electrode body 700. The electrode body connection portion 630 can be extended according to the length of the electrode body in the Z-axis direction. Therefore, the degree of freedom in designing the joint area and joint position in the joint between the electrode body connection portion 630 and the connection portion 720 increases. When the electrode body connection portion 630 is extended, it is sufficient to extend the length of the connection portion in the third direction.

In the energy storage element 10, the electrode body connection portion 630 is joined to the connection portion 720 along the connection portion 720 located at both ends of the electrode body 700 in the X-axis direction (second direction). This allows the electrode body 700 to be supported by the current collector 600 at both ends in the X-axis direction. When the electrode body 700 is tilted during the manufacture of the energy storage element 10, the current collector 600 supports the electrode body 700 along the connection portion 720, so that the electrode body 700 is tilted in a stable position.

Since the terminal 300 is attached to the side wall 162 of each cutout 101, the part (main body 710, convex part of the electrode body 700) that contributes to power generation (electricity storage) of the electrode body 700 can be arranged between the pair of cutout parts. This makes it possible to reduce excess space in the container 100 and increase the energy density of the energy storage element 10. The main body 330 of the terminal 300 is arranged in the pair of cutout parts. This allows a bus bar for electrical connection to be arranged in the cutout parts (cutout parts 101) when electrically connecting multiple energy storage elements 10. Therefore, the cutout parts 101 can be effectively used.

When the other end of the current collector 600 is disposed on the opposite side of the bottom wall 161 of the electrode body 700 as in this embodiment, the current collector 600 can be directly deformed, making it easier to deform it as intended. In this case, even after manufacture, the electrode body connection portion 630 of the current collector 600 is disposed on the opposite side of the bottom wall 161 of the electrode body 700. During the manufacture of such an energy storage element 10, the current collector 600 can be deformed as intended, which is preferable.

[Description of Modifications]
The following describes various modifications of the above embodiment. In the following description, the same reference numerals may be used to refer to the same parts as those in the above embodiment or other modifications, and the description thereof may be omitted. The modifications also have the same effects as the above embodiment.

(Variation 1)
A first modification of the above embodiment will be described. In the above embodiment, the case where the electrode body connection part 630 of the current collector 600 is disposed between the container lid 170 and the electrode body 700 is exemplified. In this first modification, a case where the electrode body connection part 630a of the current collector 600a is disposed between the bottom wall 161 of the container body 160 and the electrode body 700 will be described.

6 is an explanatory diagram showing a manufacturing method of the energy storage element 10A according to the first modified example. FIG. 6 corresponds to FIG. 5. As shown in FIG. 6(a), first, the manufacturing device attaches the external gasket 400, the internal gasket 500, and the terminal 300 to the notch 101 (terminal installation surface) in the container body 160, and then crimps and joins the bent plate-shaped current collector 600a to the shaft 340 of the terminal 300. Specifically, one end (terminal connection portion 640a) of the current collector 600a is joined to the shaft 340 of the terminal 300 in a position along the side wall 162 of the container body 160. The intermediate portion between the one end and the other end (electrode body connection portion 630a) of the current collector 600a is bent to form a bent portion 650a. As a result, the current collector 600a is bent in a J-shape as a whole in FIG. 6A, and the other end of the current collector 600a is raised relative to the bottom wall 161. (In FIG. 6, the current collector 600a appears to be an inverted J when viewed from the positive side in the X-axis direction.) In this state, the manufacturing device joins the connection part 720 of the electrode body 700 to the other end of the current collector 600a. When the current collector 600a is raised relative to the bottom wall 161, it is not necessary for the current collector 600a to be at a right angle to the bottom wall 161. In the operation of joining the current collector 600a and the electrode body 700, it is sufficient that the electrode body 700 is raised at an angle that does not interfere with the bottom wall 161.

6B, the manufacturing device tilts the other end of the current collector 600a until the other end is aligned with the bottom wall 161, thereby deforming the bent portion 650a. Specifically, the current collector 600a is bent at the periphery of the tip (crimped portion) of the shaft portion 340 of the terminal 300 so that the angle of the bent portion 650a opens. The bent portion 650a is formed along the X-axis direction. The bent portion 650a is aligned with the direction in which the connection portion 720 protrudes from the main body portion 710 (second direction). As a result, the electrode body 700 is tilted from a position along the Y-axis direction (first direction) to a position along the Z-axis direction (third direction) and is accommodated in the container main body 160 in a position along the bottom wall 161. The electrode body 700 is tilted with the bent portion 650a as a reference. When the electrode body 700 is aligned along the bottom wall 161, the end of the body 710 in the positive Z-axis direction is positioned between a pair of notches 101 in the container body 160 (see FIG. 6(c)).

Then, as shown in FIG. 6(c), the manufacturing device closes the opening formed by the side wall 162 of the container body 160 with the container lid 170 and bonds the container lid 170 to the side wall 162. After bonding, the electrode body connection portion 630a of the current collector 600a is disposed between the bottom wall 161 of the container body 160 and the electrode body 700.

Even during the manufacture of such an energy storage element 10A, the electrode body 700 is simply inverted on the bottom wall 161, so the friction that the electrode body 700 experiences from the container body 160 can be reduced. In other words, damage to the electrode body 700 during manufacture can be suppressed.

(Variation 2)
Modification 2 of the above embodiment will be described. In the above embodiment, the case where the electrode body connection portion 630 of the current collector 600 is joined to only one surface of the connection portion 720 of the electrode body 700 is exemplified. In this modification 2, a case where the electrode body connection portion 630b of the current collector 600b is joined to both surfaces of the connection portion 720 will be described.

FIG. 7 is an explanatory diagram showing a manufacturing method of the energy storage element 10B according to the second modified example. FIG. 7 is a diagram corresponding to FIG. 5. As shown in FIG. 7(a), first, the manufacturing device attaches the external gasket 400, the internal gasket 500, and the terminal 300 to the notch 101 (terminal installation surface) in the container body 160, and then crimps and joins the bent plate-shaped current collector 600b to the shaft 340 of the terminal 300. Specifically, the current collector 600b has a terminal connection portion 640b and a pair of electrode body connection portions 630b (630b1, 630b2) that sandwich the terminal connection portion 640b. The terminal connection portion 640b is one end of the current collector 600b. The pair of electrode body connection portions 630b (630b1, 630b2) are the other end portions of the current collector 600b. The terminal connection portion 640b is joined to the shaft portion 340 of the terminal 300 in a position along the side wall 162 of the container body 160. Of the pair of electrode body connection portions 630b, one electrode body connection portion 630b1 extends linearly from the terminal connection portion 640b and stands up against the bottom wall 161. The other electrode body connection portion 630b2 is bent at the periphery of the tip (crimping portion) of the shaft portion 340 of the terminal 300 and stands up against the bottom wall 161. This bent portion is the bent portion 650b2. The connection portion 720 of the electrode body 700 is disposed between the pair of electrode body connection portions 630b. In this state, the manufacturing device joins the connection portion 720 of the electrode body 700 to the pair of electrode body connection portions 630b.

7B, the manufacturing device tilts each electrode body connection portion 630b until the pair of electrode body connection portions 630b are aligned with the bottom wall 161, whereby the current collector 600b is deformed between one end (terminal connection portion 640b) and the other end (electrode body connection portions 630b1, 630b2). The bending (deformation) of one side of the current collector 600b will be described. The intermediate portion between the electrode body connection portion 630b1 and the terminal connection portion 640b is bent at the periphery of the tip (crimping portion) of the shaft portion 340 of the terminal 300. This bent portion is the bent portion 650b1. The bent portion 650b1 is formed along the X-axis direction. The bent portion 650b1 is aligned along the direction in which the connection portion 720 protrudes from the main body portion 710 (second direction). The bending (deformation) of the other side of the current collector 600b will be described. The current collector 600b is bent at the periphery of the tip (crimped portion) of the shaft portion 340 of the terminal 300 so that the angle of the bent portion 650b2 is open. The bent portion 650b2 is formed along the X-axis direction. The bent portion 650b2 is along the direction in which the connection portion 720 protrudes from the main body portion 710 (second direction). As a result, the electrode body 700 is tilted from a position along the Y-axis direction (first direction) to a position along the Z-axis direction (third direction) and is housed in the container body 160 in a position along the bottom wall 161. When the electrode body 700 is in a position along the bottom wall 161, the end of the main body portion 710 in the positive Z-axis direction is disposed between a pair of notches 101 in the container body 160 (see FIG. 7C).

Then, as shown in FIG. 7(c), the manufacturing apparatus closes the opening formed by the side wall 162 of the container body 160 with the container lid 170 and joins the container lid 170 to the side wall 162. Even during the manufacturing of such an energy storage element 10B, the electrode body 700 is simply tilted over the bottom wall 161, so that the friction that the electrode body 700 experiences from the container body 160 can be reduced. In other words, damage to the electrode body 700 during manufacturing can be suppressed.

(Other Modifications)
Although the energy storage element according to the embodiment of the present invention (including its modified examples, the same applies below) has been described above, the present invention is not limited to the above-mentioned embodiment. The embodiment disclosed here is illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

In the above embodiment, the shaft portion 340 of the terminal 300 is crimped inside the container 100 while penetrating the terminal installation surface, the external gasket 400, the internal gasket 500, and the current collector 600. The shaft portion 340 is not limited to being crimped inside the container 100, and may be crimped outside the container 100. In other words, the terminal body portion 330 of the terminal 300 may be disposed inside the container, and the shaft portion 340 may protrude from the terminal body portion 300 to the outside of the container 100.

In the manufacturing method of the energy storage element described in the above embodiment, the terminal 300 is joined to one end of the current collector 600, and then the electrode body 700 is joined to the other end of the current collector 600. The order of the steps is not limited to this. In other words, the terminal 300 may be joined to the current collector 600 after the electrode body 700 is joined to the other end of the current collector 600.

In the above embodiment, an example is given of a substantially rectangular parallelepiped container 100 having a first container member, which is a container body 160 with only one side open, and a second container member, which is a container lid 170 that covers that one side. In other words, in the above embodiment, the first container member forms five of the six sides of the substantially rectangular parallelepiped shape, and the second container member forms one side. The number of substantially rectangular parallelepiped faces formed by the first container member and the second container member can be any number. Of the six sides of the substantially rectangular parallelepiped shape, the first container member may form four sides and the second container member may form two sides, or of the six sides of the substantially rectangular parallelepiped shape, the first container member may form three sides and the second container member may form three sides.

In the above embodiment, a container 100 having a pair of notches 101 is exemplified. Any number of notches may be provided, and there may be no notches. Even if there is only one notch, the main body of the electrode body can be disposed in a position adjacent to the notch within the container. This makes it possible to reduce excess space within the container and increase the energy density of the energy storage element.

In the above embodiment, a case in which only one electrode body 700 is contained in the container 100 is illustrated, but multiple electrode bodies may be contained in the container.

In the above embodiment, a wound type electrode body 700 is exemplified. However, the shape of the electrode body is not limited to the wound type, and may be a stack type in which flat electrode plates are stacked, or a shape in which the electrode plates and/or separators are folded in an accordion-like shape (such as a shape in which the separator is folded in an accordion-like shape to sandwich a rectangular electrode plate, or a shape in which the electrode plate and the separator are stacked and then folded in an accordion-like shape). In either case, the stacking direction of the electrode body may be the Y-axis direction. A stack type or accordion-like folded electrode body has a tab portion protruding in the X-axis direction, and the tab portion and the current collector are joined. The tab portion may be separate from the electrode body, or may be integral with it.

The energy storage elements of the above embodiments and the like may be used in an energy storage device. In this case, the technology of the present invention may be applied to at least one energy storage element included in the energy storage device. FIG. 8 is an explanatory diagram showing an energy storage device including energy storage elements according to the embodiments. As shown in FIG. 8, multiple energy storage elements 10 are arranged inside the energy storage device 800. The energy storage device 800 may include bus bars (not shown) that electrically connect the energy storage elements 10. The energy storage device 800 may include a status monitoring device (not shown) that monitors the status of one or more energy storage elements 10.

　Any combination of the components included in the above embodiment and its variations is also included within the scope of the present invention.

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

10, 10A, 10B Energy storage element 100 Container 101 Notch 110 First notch 120 Second notch 160 Container body 161 Bottom wall 162 Side wall 170 Container lid 300 Terminal 330 Terminal body 340

Shaft

600, 600a, 600b

Current collector

630, 630a, 630b, 630b1, 630b2

Electrode body connection

640, 640a,

640b Terminal connection

650, 650a, 650b1, 650b2 Bent portion 700 Electrode body 710 Body 711 Curved portion 712 Flat portion 720 Connection

Claims

An electrode assembly having stacked electrode plates including a connection portion;
a current collector electrically connected to the connection portion;
a container that contains the electrode assembly and the current collector;
a terminal attached to the container and electrically connected to the current collector;
The container includes a container body and a container lid body joined to the container body,
The container body includes:
A bottom wall disposed in the stacking direction of the electrode plates;
a side wall extending upward from at least a portion of the periphery of the bottom wall;
The current collector includes a terminal connection portion and an electrode body connection portion,
The terminal connection portion is joined to the terminal, and the electrode body connection portion is joined to the connection portion.
Energy storage element.
The side wall is provided in a state of rising from the entire peripheral edge of the bottom wall.
The energy storage element according to claim 1 .
The plates are stacked in a first direction,
The electrode body includes a main body portion on which an active material layer is formed,
the connection portion protrudes from the main body portion at both ends in a second direction intersecting the first direction,
The electrode body connection portion is aligned along a third direction intersecting the first direction and the second direction.
The energy storage element according to claim 1 .
The container has a rectangular shape in a plan view of the bottom wall, the corners of which are cut away,
The energy storage element according to claim 3 , wherein the terminal is attached to the side wall in the cut-out portion.
The electrode body connection portion is disposed on the electrode body on the opposite side to the bottom wall.
The energy storage element according to any one of claims 1 to 4.
An electrode assembly having stacked electrode plates including a connection portion;
a current collector electrically connected to the connection portion;
a container that contains the electrode assembly and the current collector;
a terminal attached to the container and electrically connected to the current collector,
The container includes a container body and a container lid body joined to the container body,
The container body includes:
The bottom wall and
a side wall extending upward from at least a portion of the periphery of the bottom wall;
The manufacturing method includes:
one end of the current collector is joined to the terminal and the other end of the current collector is joined to the connection portion, and then the current collector is deformed between the one end and the other end.
A method for manufacturing an energy storage element.