WO2024161990A1

WO2024161990A1 - Electric power storage element, method for manufacturing electric power storage element, and device for manufacturing electric power storage element

Info

Publication number: WO2024161990A1
Application number: PCT/JP2024/001042
Authority: WO
Inventors: 義隆塚田
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2023-02-02
Filing date: 2024-01-17
Publication date: 2024-08-08

Abstract

This electric power storage element comprises an electrode body and a container that accommodates the electrode body, wherein: the container is provided with a container main body in which at least both ends in a prescribed direction are open, and a container lid body that covers the open portion of the container main body; and the container main body is provided with a first wall portion that extends in a prescribed direction, and a pair of second wall portions that face each other and are continuous with a pair of edges following the prescribed direction of the first wall portion.

Description

ELECTRICITY STORAGE ELEMENT, METHOD FOR MANUFACTURING ELECTRICITY STORAGE ELEMENT, AND APPARATUS FOR MANUFACTURING ELECTRICITY STORAGE ELEMENT

The present invention relates to an energy storage element, a method for manufacturing an energy storage element, and an apparatus for manufacturing an energy storage element.

Conventionally, secondary batteries have been known in which a group of electrodes is housed in a cylindrical exterior case (see, for example, Patent Document 1).

JP 2005-190697 A

When inserting the electrode group into the outer case, there is a risk that the electrode group will rub against the inner surface of the outer case and will not be able to be inserted smoothly.

The present invention therefore aims to provide an energy storage element or the like in which the electrode body can be smoothly inserted into a container.

The energy storage element according to one embodiment of the present invention comprises an electrode body and a container that houses the electrode body, the container comprising a container body that is open at least at both ends in a predetermined direction, and a container lid that closes the open portion of the container body, the container body comprising a first wall portion that extends in the predetermined direction, and a pair of second wall portions that are continuous with a pair of edges of the first wall portion that are aligned in the predetermined direction and face each other, and the thickness of at least one of the pair of second wall portions is thinner than the thickness of the first wall portion.

A manufacturing method of an energy storage element according to one embodiment of the present invention is a manufacturing method of an energy storage element comprising an electrode body and a container that houses the electrode body, the container comprising a container body with at least both ends in a predetermined direction that are open, and a container lid that closes the open portion of the container body, the container body comprising a first wall portion extending in the predetermined direction, and a pair of second wall portions that are continuous with a pair of edges of the first wall portion along the predetermined direction and face each other, and the manufacturing method includes inserting the electrode body between the pair of second wall portions in a state in which at least one of the pair of second wall portions is deformed so as to widen the gap between the pair of second wall portions of the container body.

The manufacturing apparatus for an energy storage element according to one embodiment of the present invention is an energy storage element manufacturing apparatus comprising an electrode body and a container for housing the electrode body, the container comprising a container body having at least both ends open in a predetermined direction and a container lid for closing the open portion of the container body, the container body comprising a first wall portion extending in the predetermined direction and a pair of opposing second wall portions continuing from a pair of edges of the first wall portion along the predetermined direction, the manufacturing apparatus comprising a deformation unit for deforming at least one of the pair of second wall portions of the container body so as to increase the spacing between the pair of second wall portions, and an insertion unit for inserting the electrode body between the pair of second wall portions after deformation by the deformation unit.

According to the present invention, the electrode body can be smoothly inserted into the container 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 perspective view showing a configuration of an electrode body according to an embodiment. FIG. 4 is a block diagram showing the functional parts of the manufacturing apparatus according to the embodiment. FIG. 5 is a perspective view showing a schematic configuration of a manufacturing apparatus according to an embodiment. FIG. 6 is a diagram showing a state of a container body according to the embodiment before and after elastic deformation. FIG. 7 is a perspective view showing a schematic configuration of an energy storage element manufacturing apparatus according to the first modification. FIG. 8 is an exploded perspective view showing a container body and a container lid according to the second modification. FIG. 9 is a diagram showing a state of a container body according to the second modification before and after elastic deformation. FIG. 10 is an explanatory diagram showing an energy storage device including an energy storage element according to an embodiment.

(1) An energy storage element according to one aspect of the invention comprises an electrode body and a container that houses the electrode body, the container comprising a container body that is open at least at both ends in a predetermined direction, and a container lid that closes the open portion of the container body, the container body comprising a first wall portion that extends in the predetermined direction, and a pair of second wall portions that are continuous with a pair of edges of the first wall portion that run along the predetermined direction and face each other, and the thickness of at least one of the pair of second wall portions is thinner than the thickness of the first wall portion.

As a result, the thickness of at least one second wall portion is thinner than the thickness of the first wall portion, so that at least one second wall portion can be easily elastically deformed during the manufacture of the energy storage element. Therefore, the electrode body can be inserted between the pair of second wall portions after elastically deforming at least one second wall portion so that the gap between the pair of second wall portions increases. This reduces friction between the pair of second wall portions and the electrode body during insertion, so that the electrode body can be smoothly inserted into the container.

(2) In the energy storage element described in (1) above, the container body may have a third wall portion that is continuous with the edge of the pair of second wall portions opposite the first wall portion and faces the first wall portion, and the thickness of at least one of the pair of second wall portions may be thinner than the thickness of the third wall portion.

As a result, even in a container body having a first wall portion, a pair of second wall portions, and a third wall portion, the thickness of at least one second wall portion is thinner than the thickness of each of the first wall portion and the third wall portion, so that at least one second wall portion can be easily elastically deformed during the manufacture of the energy storage element.

(3) In the energy storage element described in (1) or (2) above, the electrode body may have a flat portion, and the pair of second wall portions may overlap with the flat portion.

By doing this, at least one of the second walls is elastically deformed so that the gap between the pair of second walls is widened, and then the electrode body is inserted between the pair of second walls with the flat portion facing the second wall. This further reduces friction between the pair of second walls and the electrode body when inserting the electrode body into the container, allowing the electrode body to be inserted into the container more smoothly.

(4) A manufacturing method of an energy storage element according to one embodiment of the present invention is a manufacturing method of an energy storage element comprising an electrode body and a container that houses the electrode body, the container comprising a container body having at least both ends open in a predetermined direction and a container lid that closes the open portion of the container body, the container body comprising a first wall portion extending in the predetermined direction and a pair of second wall portions that are continuous with a pair of edges of the first wall portion along the predetermined direction and face each other, and the manufacturing method includes inserting the electrode body between the pair of second wall portions in a state in which at least one of the pair of second wall portions is deformed so as to increase the spacing between the pair of second wall portions of the container body.

By deforming at least one of the second walls so as to widen the gap between the pair of second walls and then inserting the electrode body between the pair of second walls, friction between the pair of second walls and the electrode body during insertion can be reduced. Therefore, the electrode body can be smoothly inserted into the container.

(5) In the method for manufacturing an energy storage element described in (4) above, at least one of the pair of second wall portions may be deformed by pulling the at least one second wall portion outward.

In this way, at least one of the pair of second wall portions is deformed by pulling at least one of the pair of second wall portions outward. Therefore, at least one of the second wall portions can be easily deformed so as to increase the distance between the pair of second wall portions.

(6) In the manufacturing method of the energy storage element described in (4) above, the container body may have a third wall portion that is continuous with the edge of the pair of second walls opposite the first wall portion and faces the first wall portion, and the manufacturing method may include deforming the pair of second walls by increasing the internal pressure of the container body to be higher than the external pressure.

In this way, the pair of second wall portions are deformed by increasing the internal pressure of the container body to be higher than the external pressure, so that each second wall portion can be deformed in a well-balanced manner.

(7) An apparatus for manufacturing an energy storage element according to one embodiment of the present invention is an apparatus for manufacturing an energy storage element comprising an electrode body and a container for housing the electrode body, the container comprising a container body having at least both ends open in a predetermined direction and a container lid for closing the open portion of the container body, the container body comprising a first wall portion extending in the predetermined direction and a pair of second wall portions that are continuous with a pair of edges of the first wall portion along the predetermined direction and face each other, the manufacturing apparatus comprising a deformation unit that deforms at least one of the pair of second wall portions so as to increase the spacing between the pair of second wall portions of the container body, and an insertion unit that inserts the electrode body between the pair of second wall portions after deformation by the deformation unit.

In this way, the deformation section deforms at least one of the second walls so as to increase the distance between the pair of second walls, and then the insertion section inserts the electrode body between the pair of second walls, thereby reducing friction between the pair of second walls and the electrode body during insertion. This makes it possible to smoothly insert the electrode body into the container.

(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 X-axis direction is defined as the direction along the winding axis of the electrode body, the direction in which the electrode body extends, or the direction in which a pair of short sides of the container face each other. The X-axis direction is an example of a predetermined direction. The Y-axis direction is defined as the stacking direction of the electrode plates in the flat portion of the electrode body, the direction in which the second wall portion of the container body and the flat portion of the electrode body overlap, or the thickness direction of the container. The Z-axis direction is defined as the alignment direction of the top and bottom surfaces of the container, or the up-down 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 convenience 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. Furthermore, expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the direction or attitude is not strictly speaking the same. For example, saying that two directions are orthogonal does not only mean that the two directions are completely orthogonal, but also means that the directions are substantially orthogonal, that is, that there is a difference of, for example, 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 element 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 element 10 according to the embodiment. Fig. 2 is an exploded perspective view showing each component of the energy storage element 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 also 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. Furthermore, 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 is illustrated as having a flat rectangular parallelepiped shape, but the shape of the energy storage element 10, i.e., the shape of the container 100, is not limited to 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 the like.

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, etc., the same below) are arranged at one end of the container 100 in the positive direction of the X axis, and 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 are no particular limitations on the type of electrolyte, and various types may be selected as long as they do not impair the performance of the energy storage element 10. 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 encase the electrode body 700, etc.

The container 100 is a case having an outer shape of a substantially rectangular parallelepiped that is long and flat in the X-axis direction. The length of the container 100 in the X-axis direction is three times or more 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 the length of the container 100 in the Y-axis direction. Each of the two end faces of the container 100 that face each other in the Y-axis direction is a long side surface 130. Each long side surface 130 is a flat surface that is parallel to the XZ plane and long in the X-axis direction. Each of the two end faces of the container 100 that face each other in the X-axis direction is a short side surface 135. Each short side surface 135 is a rectangular flat surface that is parallel to the YZ plane and long in the Z-axis direction. Of the two end faces of the container 100 that face each other in the Z-axis direction, the end surface in the positive direction of the Z-axis is the upper surface 140, and the end surface in the negative direction of the Z-axis is the lower surface 150. The upper surface 140 and the lower surface 150 are rectangular flat surfaces that are parallel to the XY plane and long in the X-axis direction.

The container 100 comprises a container body 160 and a pair of container lids 170, and is formed into a substantially rectangular parallelepiped shape by assembling the container body 160 and the pair of container lids 170. The container body 160 comprises a pair of long sides 130, an upper surface 140, and a lower surface 150.

Specifically, the container body 160 is a rectangular cylindrical member with open portions at both ends in the X-axis direction. The container body 160 includes a first wall portion 161, a pair of second wall portions 162, and a third wall portion 163. The first wall portion 161 is a rectangular flat portion extending in the X-axis direction. The pair of second wall portions 162 are rectangular flat portions extending in the X-axis direction that continue from the edge of the first wall portion 161 along the X-axis direction and face each other in the Y-axis direction. The edge of the first wall portion 161 extending in the X-axis direction can also be referred to as the first edge. Each second wall portion 162 includes a long side surface 130. The third wall portion 163 is a rectangular flat portion extending in the X-direction that continues from the edge of the pair of second wall portions 162 opposite the first wall portion 161 and faces the first wall portion 161 in the Z-axis direction. The edge of the pair of second walls 162 opposite the first wall 161 can also be referred to as the second edge, and the second edge can also be referred to as an edge extending in the X-axis direction, separated from the first wall 161. The outer surface of the first wall 161 is the lower surface 150, the outer surface of each second wall 162 is the long side surface 130, and the outer surface of the third wall 163 is the upper surface 140. Of the walls along the X-axis direction that the container body 160 has, the length between the pair of opposing second walls 162 is shorter than the length between the opposing first wall 161 and third wall 163.

The pair of container lids 170 are joined to the container body 160 so as to close both ends of the container body 160 in the X-axis direction, which are the open portions of the container body 160. Each container lid 170 is a rectangular flat metal plate extending in the Z-axis direction. The outer surface of each container lid 170 is the short side 135.

With this configuration, the container 100 is sealed by having the electrode body 700 and the like housed in the container body 160 and then joining the container body 160 and the container lid 170 by welding or the like. There are no particular limitations on the material of the container 100 (container body 160 and container lid 170), but it is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

Although not shown here, at least one of the pair of container lids 170 may be formed with a liquid injection section and a gas exhaust valve. The liquid injection section is a section for injecting electrolyte into the container 100 during the manufacture of the energy storage element 10. The gas exhaust valve is a safety valve that releases pressure inside the container 100 if the pressure rises excessively.

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 also 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 lid 170.

In this embodiment, the terminal 300 includes a terminal body 330 and a shaft 340 protruding from the terminal body 330. The terminal body 330 is a portion that protrudes outward from the short side surface 135. Each container lid 170 has a through hole 171 through which the shaft 340 passes. The shaft 340 is connected (joined) to the current collector 600 by being crimped while passing through the container lid 170, the external gasket 400, the internal gasket 500, and the current collector 600.

The current collectors 600 are arranged on both sides of the electrode body 700 in the X-axis direction. The current collectors 600 are electrically conductive members (positive electrode current collector 610 and negative electrode current collector 620) that are connected (joined) to the electrode body 700 and the terminal 300 and electrically connect the electrode body 700 and the terminal 300. Specifically, the current collector 600 is integrally provided with a first joint 630 that is connected (joined) to the connection part 720 of the electrode body 700 described later, and a second joint 640 that is connected (joined) to the terminal 300. The first joint 630 and the second joint 640 are each flat plate-shaped parts and are formed by bending a single flat plate member. The material of the current collectors 600 is not particularly limited, but the positive electrode current collector 610 is formed of a conductive member such as aluminum or an aluminum alloy. The negative electrode current collector 620 is formed of a conductive member such as copper or a copper alloy.

The external gasket 400 is a rectangular plate-shaped insulating sealing member that is disposed between the container lid 170 and the terminal 300 and insulates and seals between the container lid 170 and the terminal 300. The internal gasket 500 is a rectangular plate-shaped insulating sealing member that is disposed between the container lid 170 and the first joint 630 or the second joint 640 and insulates and seals between the container lid 170 and the first joint 630 or the second joint 640. 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 a storage element (power generating element) formed by winding an electrode plate. 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. The electrode body 700 has a shape in which the length in the X-axis direction is 300 mm or more, specifically, about 500 mm to 1500 mm. Therefore, the length of the electrode body 700 in the X-axis direction is longer than the length of the electrode body 700 in the Z-axis direction. The length of the electrode body 700 in the X-axis direction is three times or more the length in the Z-axis direction. The electrode body 700 has a main body 710 and a plurality of connection parts 720 protruding from the main body 710. As described above, the connection parts 720 are connected (joined) to the current collector 600.

Specifically, the multiple connection parts 720 protrude one by one from both end faces in the X-axis direction of the main body part 710. A positive electrode connection part 721 is provided on one end face in the positive X-axis direction of the main body part 710 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 in the negative X-axis direction of the main body part 710 at a predetermined distance from the end face in the positive 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. 3 is a perspective view showing the configuration of an electrode assembly 700 according to an embodiment. Specifically, Fig. 3 shows the configuration in a partially developed state in which the electrode plates in the electrode assembly 700 are wound. As shown in Fig. 3, the electrode assembly 700 includes 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 polyolefin resin such as polyethylene.

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

separators

761 and 762. The electrode body 700 is formed by stacking a negative electrode plate 750, a separator 761, a positive electrode plate 740, and a 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 a winding axis L extending in the X-axis direction to form a 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.

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 3 correspond to the active material layer non-formed portions.

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

separators

761, 762 are wound, the protruding pieces 743 of the positive electrode plate 740 overlap at one end face of the main body 710 (the end face in the positive direction of the X-axis). The portion where the protruding pieces 743 of the positive electrode plate 740 overlap is the positive electrode connection part 721. Similarly, at the other end face of the main body 710 (the end face in the negative direction of the X-axis), the protruding pieces 753 of the negative electrode plate 750 overlap. The portion where the protruding pieces 753 of the negative electrode plate 750 overlap is the negative electrode connection part 722.

The main body 710 is an elongated cylindrical portion (active material layer forming portion) formed by winding together 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 portion 711 is a curved portion 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. In other words, the pair of curved portions 711 are curved portions that protrude from the flat portion 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 a pair of curved portions 711. In the flat portion 712, multiple wound electrode plates (positive electrode plate 740 and negative electrode plate 750) are stacked in the Y-axis direction. In other words, in the flat portion 712, the Y-axis direction is the stacking direction of the multiple electrode plates. In this disclosure, the main stacking direction of the electrode body 700 is defined as the Y-axis direction. The electrode plates in the portion that constitutes the flat portion 712 are more likely to bend than the electrode plates in the portion that constitutes the curved portion 711. Therefore, the outer surface of the flat portion 712 (the surface facing the Y-axis direction) is more likely to be slightly recessed or bulged in the Y-axis direction. Therefore, when the electrode body 700 is inserted into the container body 160 from the X-axis direction, the flat portion 712 is more likely to come into contact with the X-axis end, which is the open portion of the container body 160. Therefore, for example, by making it easier to deform the second wall portion 162 of the container body 160 that faces the flat portion 712 of the electrode body 700 outward in the Y-axis direction, it becomes easier to insert the electrode body 700 into the container body 160.

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.

[Electricity storage element manufacturing apparatus]
Next, a manufacturing apparatus 900 for manufacturing the energy storage element 10 will be described. Specifically, the manufacturing apparatus 900 is an apparatus for inserting the electrode body 700 into the container body 160. FIG. 4 is a block diagram showing the functional parts of the manufacturing apparatus 900 according to the embodiment. FIG. 5 is a perspective view showing a schematic configuration of the manufacturing apparatus 900 according to the embodiment. In FIG. 5, a part of the first chamber 911 and the second chamber 912 of the holding part 910 is shown in a cross-sectional view. As shown in FIG. 4, the manufacturing apparatus 900 includes the holding part 910, the deformation part 920, and the insertion part 930. Here, the deformation part 920 and the insertion part 930 may operate based on the operation of an operator, or may operate based on the control of a control part such as a microcomputer.

The holding part 910 is a part that holds the container body 160. Specifically, the holding part 910 includes a first chamber 911 and a second chamber 912. The first chamber 911 and the second chamber 912 are arranged side by side in the X-axis direction, and the container body 160 is bridged between them. One end of the container body 160 in the negative X-axis direction is detachably fixed to the wall of the first chamber 911 while penetrating the wall. The other end of the container body 160 in the positive X-axis direction is detachably fixed to the wall of the second chamber 912 while penetrating the wall of the second chamber 912. This makes the internal space of the first chamber 911, the internal space of the container body 160, and the internal space of the second chamber 912 continuous. When the container body 160 is fixed, the first chamber 911 and one end of the container body 160 are sealed, and the second chamber 912 and the other end of the container body 160 are sealed. This prevents the gas in the container body 160 from escaping to the outside. The first chamber 911 is provided with a vent 913, and the second chamber 912 is provided with a vent 914. Although not shown, the first chamber 911 is provided with a sealed door for inserting and removing the container body 160 and the electrode assembly 700.

The deformation section 920 elastically deforms the pair of second wall sections 162 of the container body 160 so that the gap between the pair of second wall sections 162 increases. Specifically, the deformation section 920 is a gas pump, and is connected to the vent 913 of the first chamber 911 and the vent 914 of the second chamber 912 via piping (not shown). When the deformation section 920 supplies gas to each of the first chamber 911 and the second chamber 912, the inside of the container body 160 is pressurized, and the internal pressure of the container body 160 becomes higher than the external pressure. This causes the container body 160 to elastically deform and swell.

Here, an example is shown in which the inside of the container body 160 is pressurized so that the internal pressure of the container body 160 is higher than the external pressure. In addition, the outside of the container body 160 may be depressurized so that the internal pressure of the container body 160 is higher than the external pressure, thereby inflating the container body 160.

6 is a diagram showing the state before and after elastic deformation of the container body 160 according to the embodiment. The solid line indicates the state before elastic deformation, and the two-dot chain line indicates the state after elastic deformation. Here, in the container body 160, the thickness t2 of each second wall portion 162 is thinner than the thickness t1 of the first wall portion 161. This makes each second wall portion 162 more susceptible to elastic deformation than the first wall portion 161. Furthermore, the thickness t2 of each second wall portion 162 is thinner than the thickness t3 of the third wall portion 163. This makes each second wall portion 162 more susceptible to elastic deformation than the third wall portion 163. When the internal pressure of the container body 160 becomes higher than the external pressure due to the deformation portion 920, each second wall portion 162 is elastically deformed so that the interval between each second wall portion 162 of the container body 160 increases (see the two-dot chain line in FIG. 6).

The insertion portion 930 inserts the electrode body 700 between the pair of second wall portions 162 after the elastic deformation of the second wall portions 162 by the deformation portion 920. Specifically, the insertion portion 930 has an arm 931 arranged in the second chamber 912 and slidably driven in the X-axis direction. The arm 931 is a rod-shaped body extending in the X-axis direction, and a gripping portion 932 is provided at its end in the negative X-axis direction to grip the end of the electrode body 700 in the positive X-axis direction. When the container body 160 is spanned across the first chamber 911 and the second chamber 912, the arm 931 moves from the second chamber 912 in the negative X-axis direction to enter the container body 160, and brings the gripping portion 932 closer to the end in the positive X-axis direction of the electrode body 700 waiting in the first chamber 911. Thereafter, when the gripping portion 932 grips the end of the electrode body 700 in the positive direction of the X-axis, the arm 931 moves in the positive direction of the X-axis and inserts the electrode body 700 between the pair of second wall portions 162 of the container body 160.

[Method of manufacturing the energy storage element]
Next, a method for manufacturing the energy storage element 10 will be described. First, the worker opens the sealing door of the first chamber 911 of the holding part 910, inserts the container body 160 into the first chamber 911, and then bridges the container body 160 between the first chamber 911 and the second chamber 912. At this time, the worker fixes one end of the container body 160 in the negative X-axis direction to the wall of the first chamber 911 in a state in which the end penetrates the wall. The worker fixes the other end of the container body 160 in the positive X-axis direction to the wall of the second chamber 912 in a state in which the end penetrates the wall. Thereafter, the worker inserts the electrode body 700 into the first chamber 911 through the sealing door, places the electrode body 700 at a predetermined position in the first chamber 911, and closes the sealing door.

Then, the deformation section 920 supplies gas to each of the first chamber 911 and the second chamber 912. By making the internal pressure of the container body 160 higher than the external pressure, the container body 160 expands. This causes the pair of second wall sections 162 of the container body 160 to elastically deform so that the distance between them increases. The deformation section 920 maintains the container body 160 in an elastically deformed state.

In this state, the insertion part 930 moves the arm 931 from the second chamber 912 in the negative X-axis direction to enter the container body 160, thereby bringing the gripping part 932 closer to the end of the electrode body 700 in the positive X-axis direction waiting in the first chamber 911. Thereafter, when the gripping part 932 grips the end of the electrode body 700 in the positive X-axis direction, the arm 931 moves in the positive X-axis direction to insert the electrode body 700 between the pair of second wall parts 162 of the container body 160. At this time, since the gap between the pair of second wall parts 162 of the container body 160 has widened, the electrode body 700 can be smoothly inserted between the pair of second wall parts 162.

Once the insertion is complete, the deformation portion 920 stops the supply of gas. This causes the container body 160 to elastically return to its original shape. The insertion portion 930 releases the grip by the gripping portion 932. The operator then opens the sealed door and removes the container body 160 and the electrode body 700 from the first chamber 911.

Then, the worker assembles the positive electrode connection part 721 of the electrode body 700, the current collector 600, the positive electrode terminal 310, the container lid body 170 in the positive direction of the X-axis, the external gasket 400, and the internal gasket 500. Similarly, the worker assembles the negative electrode connection part 722 of the electrode body 700, the current collector 600, the negative electrode terminal 320, the container lid body 170 in the negative direction of the X-axis, the external gasket 400, and the internal gasket 500. After that, the worker joins (welds) each container lid body 170 to both ends of the container body 160 in the X-axis direction. This completes the production of the energy storage element 10.

[Effects]
As described above, according to the embodiment of the present invention, since the thickness t2 of each second wall portion 162 is thinner than the thickness t1 of the first wall portion 161, each second wall portion 162 can be easily deformed during the manufacture of the energy storage element 10. Therefore, each second wall portion 162 can be deformed so that the interval between the pair of second wall portions 162 is widened, and then the electrode body 700 can be inserted between the pair of second wall portions 162. As a result, friction between the pair of second wall portions 162 and the electrode body 700 is reduced during insertion, so that the electrode body 700 can be smoothly inserted into the container body 160.

Even in the container body 160 having a first wall portion 161, a pair of second wall portions 162, and a third wall portion 163, the thickness t2 of each second wall portion 162 is thinner than the thickness t1 of the first wall portion 161 and the thickness t3 of the third wall portion 163, so that each second wall portion 162 can be easily deformed during the manufacture of the energy storage element 10.

When the electrode body 700 is housed in the container 100, the surfaces of the pair of second wall portions 162 and the surface of the flat portion 712 of the electrode body 700 overlap when viewed from the Y-axis direction. Therefore, the second walls 162 are elastically deformed so that the gap between the pair of second walls 162 widens, and then the electrode body 700 can be inserted between the pair of second walls 162 with the flat portion 712 facing the second wall portion 162. This further reduces friction between the pair of second walls 162 and the electrode body 700 when inserting the electrode body 700 into the container 100, allowing the electrode body 700 to be inserted into the container 100 more smoothly.

By increasing the internal pressure of the container body 160 to be greater than the external pressure, the pair of second wall portions 162 are deformed, allowing each second wall portion 162 to undergo elastic deformation in a balanced manner.

[Description of Modifications]
In the following, various modifications of the above embodiment will be described. In the following description, the same reference numerals will be used to designate the same parts as those in the above embodiment or other modifications, and the description thereof may be omitted.

(Variation 1)
A first modification of the above embodiment will be described. In the above embodiment, the case where the pair of second wall portions 162 are elastically deformed by increasing the internal pressure of the container body 160 to be higher than the external pressure has been exemplified. In this first modification, a case where each second wall portion 162 is elastically deformed by pulling each second wall portion 162 outward will be described.

FIG. 7 is a perspective view showing the schematic configuration of a manufacturing apparatus 900a for the energy storage element 10 according to the first modified example. FIG. 7 corresponds to FIG. 5. As shown in FIG. 7, the manufacturing apparatus 900a includes a holding portion 910a, a deformation portion 920a, and an insertion portion 930.

The holding portion 910a is equipped with a pair of pillars 915a that support the container body 160 from below. Specifically, the pair of pillars 915a are arranged at a predetermined interval in the X-axis direction, with one pillar 915a supporting the end of the container body 160 in the positive X-axis direction, and the other pillar 915a supporting the end of the container body 160 in the negative X-axis direction.

The deformation portion 920a elastically deforms each second wall portion 162 of the container body 160 by pulling each second wall portion 162 outward. Specifically, the deformation portion 920a has a pair of suction portions 925a. The pair of suction portions 925a are arranged at a predetermined interval in the Y-axis direction, and one suction portion 925a is suctioned to the second wall portion 162 in the positive direction of the Y-axis, and the other suction portion 925a is suctioned to the second wall portion 162 in the negative direction of the Y-axis. After suction, the pair of suction portions 925a move away from each other, pulling each second wall portion 162 outward. As a result, the pair of second wall portions 162 elastically deform so that the interval between the pair of second wall portions 162 of the container body 160 widens. While maintaining this state, the electrode body 700 is inserted between the pair of second wall portions 162 of the container body 160 by the insertion portion 930. At this time, the gap between the pair of second walls 162 of the container body 160 has widened, so the electrode body 700 can be smoothly inserted between the pair of second walls 162.

In this way, each second wall portion 162 is deformed by being pulled outward, so that each second wall portion 162 can be easily deformed so that the spacing between each second wall portion 162 increases.

Here, the case where the deformation portion 920a adheres to each second wall portion 162 and pulls it outward has been exemplified, but each second wall portion 162 may be pulled outward while being gripped. The pair of adhesion portions 925a are separated from each other to pull each second wall portion 162 outward, but only one of the pair of adhesion portions 925a adhered to the pair of second wall portions 162 may be pulled outward.

(Variation 2)
A second modification of the above embodiment will be described. In the above embodiment, the container 100 is illustrated as including a cylindrical container body 160 having open portions at both ends in the X-axis direction, and a pair of container lids 170 that close the open portions of the container body 160. However, the container body may have any shape as long as both ends in the X-axis direction are open. The container lids may have any shape as long as they close the open portions of the container body.

FIG. 8 is an exploded perspective view showing the container body 160a and the container lid 170a according to the second modification. As shown in FIG. 8, the container body 160a has open portions at both ends in the X-axis direction and at the end in the positive Z-axis direction, and is a U-shaped member as viewed from the X-axis direction. The container body 160a has a first wall portion 161a and a pair of second walls 162a. The container lid 170a is an inverted U-shaped member as viewed from the Y-axis direction, and is joined to the container body 160a so as to close the open portion of the container body 160a. The container lid 170a has a third wall portion 163a and a pair of fourth walls 164a. The pair of fourth walls 164a are rectangular flat plate-shaped portions that are continuous from both ends of the third wall portion 163a and extend in the Z-axis direction.

In the above-described container body 160a, the electrode body 700 can be inserted from both sides in the X-axis direction (the positive and negative directions of the X-axis) and from the positive direction of the Z-axis. When the electrode body 700 is inserted from either direction, as exemplified in Modification Example 1, by pulling each second wall portion 162a outward, it is possible to elastically deform each second wall portion 162a.

FIG. 9 is a diagram showing the state of the container body 160a according to the second modification example before and after elastic deformation. FIG. 9 is a diagram corresponding to FIG. 6. In the container body 160a, the thickness t2a of each second wall portion 162a is thinner than the thickness t1a of the first wall portion 161a. This makes each second wall portion 162a more susceptible to elastic deformation than the first wall portion 161a. In other words, when each second wall portion 162a is pulled outward by the deformation portion 920a, each second wall portion 162a is elastically deformed so that the spacing between each second wall portion 162a of the container body 160a increases (see the two-dot chain line in FIG. 9).

(others)
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.

For example, in the above embodiment, a case has been exemplified in which each of the pair of second wall portions 162 is elastically deformed during manufacturing. However, only one of the second wall portions may be elastically deformed. In this case, the thickness of only the one of the second wall portions that is elastically deformed may be thinner than the thickness of the first wall portion.

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, it is preferable that the stacking direction of the electrode body is 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 600 are joined. The tab portion may be separate from the electrode body 700, or may be integral with it. In a stack type electrode body, the surfaces at both ends in the stacking direction correspond to a pair of flat portions.

The energy storage elements of the above embodiments 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. 10 is an explanatory diagram showing an energy storage device 800 including an energy storage element 10 according to an embodiment. As shown in FIG. 10, multiple energy storage elements 10 are arranged inside the energy storage device 800. The energy storage device 800 may include a bus bar (not shown) that electrically connects 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 Energy storage element 100

Container

160,

160a Container body

161, 161a

First wall portion

162, 162a

Second wall portion

163, 163a Third wall portion 164a Fourth wall portion 170, 170a Container lid body 300 Terminal 330 Terminal body portion 340 Shaft portion 400 External gasket 500 Internal gasket 600 Current collector 630 First bonding portion 640 Second bonding portion 700 Electrode body 710 Body portion 711 Curved portion 712 Flat portion 720 Connection portion 800

Energy storage device

900,

900a Manufacturing device

910, 910a Holding portion 911 First chamber 912

Second chamber

913, 914 Vent 915a

Column portion

920, 920a Deformation portion 925a Adsorption portion 930 Insertion portion 931 Arm 932 Grip portion L Winding axis t1, t1a, t2, t2a, t3 Wall thickness

Claims

An electrode body;
A container for accommodating the electrode assembly,
The container comprises:
A container body having at least both ends in a predetermined direction open;
a container lid for closing an open portion of the container body,
The container body includes:
A first wall portion extending in the predetermined direction;
a pair of second wall portions that are continuous with a pair of edges of the first wall portion along the predetermined direction and face each other;
a thickness of at least one of the pair of second wall portions is thinner than a thickness of the first wall portion.
The container body includes:
a third wall portion that is continuous with an edge of the pair of second wall portions opposite to the first wall portion and faces the first wall portion,
The energy storage element according to claim 1 , wherein a thickness of at least one of the pair of second wall portions is thinner than a thickness of the third wall portion.
The electrode body has a flat portion,
The energy storage element according to claim 1 , wherein the pair of second wall portions and the flat portion overlap each other.
A method for manufacturing an electric storage element including an electrode assembly and a container for accommodating the electrode assembly,
The container comprises:
A container body having at least both ends in a predetermined direction open;
a container lid for closing an open portion of the container body,
The container body includes:
A first wall portion extending in the predetermined direction;
a pair of second wall portions that are continuous with a pair of edges of the first wall portion along the predetermined direction and face each other;
The manufacturing method includes:
A method for manufacturing an energy storage element, comprising: inserting the electrode body between the pair of second wall portions while deforming at least one of the pair of second wall portions of the container body so as to widen the gap between the pair of second wall portions.
The method for manufacturing an energy storage element according to claim 4 , further comprising the step of: pulling outwardly at least one of the pair of second wall portions, thereby deforming the at least one second wall portion.
The container body includes:
a third wall portion that is continuous with an edge of the pair of second wall portions opposite to the first wall portion and faces the first wall portion,
The manufacturing method includes:
The method for manufacturing an energy storage element according to claim 4 , wherein the pair of second walls are deformed by increasing an internal pressure of the container body to be higher than an external pressure.
An apparatus for manufacturing an electric storage element comprising an electrode body and a container for accommodating the electrode body,
The container comprises:
A container body having at least both ends in a predetermined direction open, and a container lid for closing the open portion of the container body,
The container body includes:
A first wall portion extending in the predetermined direction;
a pair of second wall portions that are continuous with a pair of edges of the first wall portion along the predetermined direction and face each other;
The manufacturing apparatus includes:
a deformation portion that deforms at least one of the pair of second wall portions of the container body so that the interval between the pair of second wall portions is increased;
an insertion portion that inserts the electrode body between the pair of second wall portions after deformation by the deformation portion.