JP2017191683A - Storage device manufacturing method and storage device container cover plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for manufacturing a high-quality power storage element, which is a power storage element including a container in which a container body and a cover plate are joined by welding. A method of manufacturing a power storage device 10 including a container 100 having a container body 101 and a lid plate 110, wherein an arch-shaped lid plate 110 that is convex in a predetermined direction is inserted into an opening 102 of the container body 101. Then, a pressing step for pressing and spreading the lid plate 110 by pressing from a predetermined direction, and a welding step for welding the lid plate 110 pressed and spread in the pressing step and the container body 101 are included. [Selection diagram] Fig. 5

Description

  The present invention relates to a method for manufacturing a power storage element including a container, and a cover plate for the container of the power storage element.

  Conventionally, a storage element such as a lithium ion secondary battery includes, for example, a container and an electrode body accommodated in the container, and is charged and discharged via an electrode terminal disposed in the container.

  In the electricity storage device having such a structure, the container is composed of, for example, a container main body and a lid plate, and in the state in which an element such as an electrode body is accommodated in the container main body, Are joined by laser welding or the like. Specifically, in laser welding, the metal of the part is melted by irradiating a laser beam to the joining part (boundary part) of the lid plate and the opening of the container body. Are joined.

  When such metal welding is performed, the gas generated in the molten metal or the gas that has penetrated into the molten metal remains without being released to the outside, and as a result, a void (for example, “ Called "blowhole").

  For such a problem, for example, in Patent Document 1, when a galvanized steel sheet is overlapped and laser-welded, a convex portion is provided on one of the two steel sheets so that a predetermined distance is provided between the two steel sheets. It is disclosed that a gap in the distance can be opened, thereby suppressing the occurrence of blow holes.

JP 2009-72799 A

  For example, in the case of a lithium ion secondary battery, the container material is generally a different type of metal from the zinc-based plated steel sheet, such as an aluminum alloy. In this case, the above-described conventional technique should be applied. I can't. Moreover, since the width | variety of the surface where a container main body and a cover plate mutually match | combine is narrow, it is not realistic to form the fine convex part of predetermined height in the said surface.

  Also, in order to accurately weld the lid plate and the container body, welding is performed while pressing the lid plate in the direction of the container body. If the pressing force at this time is too high, the gas in the molten metal There is a problem that blowholes are easily generated. Moreover, when the said pressing force is weak, the part which forms a big clearance gap in the cover plate not along the opening of a container main body, for example arises, As a result, the problem that a welding defect generate | occur | produces arises.

  In view of the above-described conventional problems, the present invention is a power storage element including a container in which a container body and a cover plate are joined by welding, and a manufacturing method for manufacturing a high-quality power storage element, and the power storage element It aims at providing the cover plate used for.

  In order to achieve the above object, a method for manufacturing a power storage device according to one aspect of the present invention is a method for manufacturing a power storage device including a container having a container body and a cover plate, and has a convex arch shape in a predetermined direction. By pressing the lid plate against the opening of the container body from the predetermined direction, and welding the lid plate, the lid plate spread in the pressing step, and the container body. Welding process.

  According to this manufacturing method, for example, when a lid plate is welded to the upper opening of the container body, the arch-shaped lid plate is convex upward and pressed from above, for example, to be flattened. Welded in a state. In other words, due to the elastic force of the lid plate, a repulsive force is generated in the portion (intermediate portion) between the both end portions of the lid plate, and both ends of the arched lid plate are pushed against the container body. Hit. As a result, it is possible to prevent the intermediate portion of the lid plate from being excessively pressed against the container body, and the occurrence of problems such as blow holes due to excessive pressing is suppressed. In addition, since both ends are pressed against the container body by pressing the intermediate part, as a result, a problem such as displacement of the cover plate or part of the cover plate floating from the container body occurs during welding. hard. Therefore, the reliability of joining the container body and the cover plate is improved, and as a result, a highly reliable power storage element can be obtained.

  In the method for manufacturing a power storage element according to one embodiment of the present invention, the cover plate may include a gas discharge valve at an intermediate portion that is a portion between both end portions in the longitudinal direction.

  According to this manufacturing method, the possibility of occurrence of defects such as poor welding is reduced at the joint portion between the portion of the arch-shaped lid plate that is pressed in the pressing step (that is, the intermediate portion) and the container body. For example, the bonding strength is improved. Therefore, the tolerance with respect to the internal pressure of a container of the intermediate part of the cover board which rigidity reduced by having arrange | positioned a gas exhaust valve can be improved.

  Further, in the method for manufacturing an energy storage device according to one aspect of the present invention, in the pressing step, at least one end portion in the longitudinal direction of the lid plate is pressed from the inside of the opening by pressing the lid plate. It may be moved toward the periphery of the opening.

  According to this manufacturing method, when the cover plate is disposed in the opening of the container body, the end of the cover plate does not collide with the peripheral edge of the opening from above, for example. The generation of minute metal pieces (foreign matter) is suppressed.

  Further, the lid plate of the container of the electricity storage device according to one aspect of the present invention is a lid plate for closing the planar opening of the container body included in the container of the electricity storage device, and projects toward the opposite side of the container body. It is arched.

  According to this configuration, when the lid plate is welded to the flat opening at the top of the container body at the time of manufacturing the electric storage element, the arch-shaped lid plate is convex upward and pressed down from above to be flat. It is spread and welded in that state. In other words, due to the elastic force of the lid plate, a repulsive force is generated in the portion (intermediate portion) between both ends of the lid plate, and both ends of the arch-shaped lid plate are pushed by the container. . As a result, it is possible to prevent the intermediate portion of the lid plate from being excessively pressed against the container body, and the occurrence of problems such as blow holes due to excessive pressing is suppressed. In addition, since both ends are pressed against the container body by pressing the intermediate part, as a result, a problem such as displacement of the cover plate or part of the cover plate floating from the container body occurs during welding. hard. Therefore, the reliability of joining the container body and the cover plate is improved, and as a result, a highly reliable power storage element can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, it is an electrical storage element provided with the container by which the container main body and the cover plate were joined by welding, Comprising: An electrical storage element with high quality can be manufactured. Moreover, according to this invention, the cover plate used for the electrical storage element can be provided.

It is a perspective view which shows the external appearance of the electrical storage element which concerns on embodiment. It is a perspective view which shows the state before welding of the container main body with which the electrical storage element which concerns on embodiment is equipped, and each cover plate. It is a perspective view of the cover plate which concerns on embodiment. It is a 1st figure which shows a part of manufacturing method of the electrical storage element which concerns on embodiment. It is a 2nd figure which shows a part of manufacturing method of the electrical storage element which concerns on embodiment. It is a 3rd figure which shows a part of manufacturing method of the electrical storage element which concerns on embodiment. It is a 4th figure which shows a part of manufacturing method of the electrical storage element which concerns on embodiment. It is a figure which shows the detail of the pressing process which the manufacturing method of the electrical storage element which concerns on embodiment contains.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each figure is a schematic diagram and is not necessarily illustrated exactly.

  The embodiment described below shows a specific example of the present invention. The shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, order of manufacturing steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

  First, with reference to FIG. 1 and FIG. 2, a general description of the energy storage device 10 according to the embodiment will be given.

  FIG. 1 is a perspective view showing an external appearance of a power storage element 10 according to the embodiment. FIG. 2 is a perspective view illustrating a state before welding of the container main body 101 and the cover plate 110 included in the energy storage device 10 according to the embodiment. In FIG. 2, elements such as the electrode body 400 housed in the container 100 are not shown.

  For convenience of explanation, FIG. 1 and the subsequent drawings are described with the Z-axis direction as the vertical direction. However, in the actual usage, the Z-axis direction may not match the vertical direction.

  The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage element 10 is applied to, for example, an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or the like.

  The power storage element 10 includes a UPS (uninterruptible power supply), a natural energy storage power storage device, a regenerative energy storage power storage device such as a train (installed inside or outside the vehicle), an engine start power storage device, Alternatively, it may be applied to AGV (automated guided vehicle) or the like.

  In addition, the electrical storage element 10 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it. Further, the shape of the electricity storage element 10 is not limited to a square shape, and may be another shape such as a cylindrical shape.

  As shown in FIGS. 1 and 2, the electricity storage element 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300. In addition, an electrode body 400 is accommodated inside a container body 101 included in the container 100, and a lid plate 110 is disposed so as to close the opening 102 of the container body 101. In FIG. 1, the electrode body 400 is conceptually represented by a rectangular parallelepiped drawn by a dotted line, and the shape and size of the electrode body 400 are not limited to the shape and size shown in FIG. 1.

  The container 100 includes a container main body 101 having a rectangular cylindrical shape and a bottom, and a lid plate 110 that is a plate-like member attached so as to close the opening 102 of the container main body 101. In addition, the container 100 has a structure in which after the electrode body 400 and the like are accommodated therein, the lid plate 110 and the container body 101 are welded to seal the inside.

  Specifically, the edge of the container body 101 that forms the opening 102 (the upper edge of the container body 101 in FIG. 2, hereinafter referred to as “the edge that forms the opening 102”) is one in the present embodiment. It arrange | positions in XY plane, Thereby, the opening 102 exists in the container main body 101 as a plane opening. In the present embodiment, an arcuate lid plate 110 that is convex on the side opposite to the container body 101 is spread and welded to the opening 102. This welding process will be described later with reference to FIGS. The term “plane” includes not only a complete plane but also a substantially plane.

  Further, as the material of the lid plate 110 and the container main body 101, for example, a weldable metal such as stainless steel, aluminum, or an aluminum alloy is employed.

  A gas discharge valve 170 is provided in the middle part of the cover plate 110. The gas discharge valve 170 is provided in the power storage element 10 as a safety mechanism that opens when the internal pressure of the container 100 rises and releases the gas inside the container 100.

  The intermediate portion of the lid plate 110 is a portion between both end portions in the longitudinal direction of the lid plate 110 (X-axis direction in the present embodiment). For example, the intermediate portion of the lid plate 110 can be defined as a portion between the positive electrode terminal 200 and the negative electrode terminal 300 in the lid plate 110. The intermediate portion of the lid plate 110 can also be defined as a portion including the entire length of the gas exhaust valve 170 in the X-axis direction when viewed from the side (when viewed from the Y-axis direction).

  The electrode body 400 includes a positive electrode plate, a negative electrode plate, and a separator, and is a member that can store electricity. In the present embodiment, the power storage element 10 includes a wound electrode body 400 formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween. In addition, the electrode body 400 is accommodated in the container body 101 in a posture in which the winding shaft is parallel to the direction connecting the lid plate 110 and the bottom surface of the container body 101, that is, the Z-axis direction in the present embodiment. Has been.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400 through a positive electrode current collector (not shown). The negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 400 via a negative electrode current collector (not shown). That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 400 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 400, It is an electrode terminal made of metal for introducing.

  The positive electrode terminal 200 is attached to the lid plate 110 via an insulating gasket 125, and the negative electrode terminal 300 is attached to the lid plate 110 via an insulating gasket 135. In addition, a gasket (not shown) is also disposed on the back side (minus side in the Z-axis direction) of each of the gaskets 125 and 135 with the lid plate 110 interposed therebetween.

  In addition to the above-described components, the power storage element 10 may include a spacer that fills the space in the container 100, an insulating film that wraps the electrode body 400, and the like. In addition, a liquid such as an electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100 of the electricity storage element 10, but the illustration of the liquid is omitted. The electrolytic solution sealed in the container 100 is not particularly limited as long as it does not impair the performance of the electricity storage element 10, and various types can be selected.

  Here, the lid plate 110 has an arcuate shape that is convex in a predetermined direction (in this embodiment, upward (Z-axis direction plus side)) before being welded to the container body 101. Thereby, the reliability of the welding location of the cover plate 110 and the container main body 101 is improved. This will be described with reference to FIGS.

  FIG. 3 is a perspective view of the cover plate 110 according to the embodiment. 4-7 is the 1st-4th figure which shows a part of manufacturing method of the electrical storage element 10 which concerns on embodiment. FIG. 8 is a diagram showing details of the pressing step included in the method for manufacturing power storage device 10 according to the embodiment. 4 to 8, elements such as the electrode body 400 accommodated in the container main body 101 and elements such as a gasket disposed on the back side of the lid plate 110 are omitted.

  As shown in FIGS. 3 and 4, the cover plate 110 according to the embodiment has an arch shape convex upward (on the opposite side to the container body 101). That is, the cover plate 110 according to the embodiment is formed in an arch shape (curved shape) in which a middle portion that is a portion between both end portions in the longitudinal direction rises upward.

  In addition, a gas exhaust valve 170 is provided in an intermediate portion of the lid plate 110, and two through holes 110a and 110b are arranged with the gas exhaust valve 170 interposed therebetween.

  As described above, the gas discharge valve 170 is a mechanism that is opened when the internal pressure of the container 100 rises. For example, the gas discharge valve 170 is provided on the cover plate 110 by press working when the arch-shaped cover plate 110 is formed. Specifically, the gas discharge valve 170 is formed by thinning a part of the metal plate, which is the material of the lid plate 110, by pressing. In addition, there is no limitation in particular in the aspect of a gas exhaust valve, For example, a gas exhaust valve is a cover plate by arrange | positioning the metal plate different from the cover plate 110 so that the hole provided in the cover plate 110 may be plugged up. 110 may be provided.

  The through hole 110 a is a hole that penetrates the shaft portion of the positive electrode terminal 200, and the through hole 110 b is a hole that penetrates the shaft portion of the negative electrode terminal 300. The shaft portion of the positive electrode terminal 200 in a state of passing through the through hole 110a is connected to the positive electrode current collector by caulking or the like. The shaft portion of the negative electrode terminal 300 in a state of passing through the through hole 110b is connected to the negative electrode current collector by caulking or the like. The positive electrode current collector is connected to the positive electrode of the electrode body 400 by welding or the like, and the negative electrode current collector is connected to the negative electrode of the electrode body 400 by welding or the like.

  In this manner, the lid plate 110 connected to the electrode body 400 is disposed so that, for example, elements such as the electrode body 400 are accommodated in the container body 101 and the opening 102 is closed.

  That is, for example, the cover plate 110 is moved from above the opening 102 toward the opening 102 as shown in FIG. 4 and placed on the opening 102 as shown in FIG. Is pressed from.

  That is, a pressing force in the direction (downward) of the container body 101 acts on the intermediate portion of the arch-shaped lid plate 110 convex in the direction opposite to the container body 101 (upward). As a result, the cover plate 110 is spread out as shown in FIGS. 5 and 6 (pressing step).

  Here, since the arch-shaped cover plate 110 is expanded while being elastically deformed, an upward repulsive force is generated at the intermediate portion of the cover plate 110 where the pressing force acts. In FIG. 6, the upward repulsive force is schematically represented by an upward dotted arrow.

  Therefore, for example, the cover plate 110 is pressed by pressing the cover plate 110 so that the intermediate portion of the cover plate 110 is close to or in contact with the opening 102 of the container body 101 (more specifically, the edge forming the opening 102). The pressing force of the intermediate portion against the edge forming the opening 102 can be made to be almost zero or a very low value. In other words, the intermediate portion, which is the pressed portion of the lid plate 110, is not excessively pressed against the container main body 101, and a state where it is close to or in contact with an appropriate welding is created.

  In order to realize a state in which the pressing force of the intermediate portion of the cover plate 110 against the edge forming the opening 102 is almost zero or a very low value, the force for pressing the cover plate 110 in the pressing step is determined by experiments or the like. It may be determined.

  Furthermore, each of the end portions (both end portions) on both sides of the intermediate portion of the cover plate 110 is not directly pressed, but is caused by the elastic force of the cover plate 110 generated by pressing the intermediate portion downward. , Pressed against the edge forming the opening 102. Thereby, the state which can be welded appropriately also about the both ends of the cover board 110 is formed. In FIG. 6, the downward elastic force is schematically represented by a downward dotted arrow.

  In addition, before and after the elastic deformation of the cover plate 110 in the pressing step, the connection is performed so that the connection between the positive electrode terminal 200 and the negative electrode terminal 300 disposed on the cover plate 110 and the electrode body 400 is maintained without any problem. There is play (margin).

  In this manner, the lid plate 110 and the container body 101 are welded in a state where the lid plate 110 is pushed and spread along the opening 102 of the container body 101 (welding process). That is, as shown in FIG. 7, for example, the laser beam L is irradiated along the abutting portion (the boundary portion between the lid plate 110 and the container body 101) between the lid plate 110 and the container body 101. Thereby, the cover plate 110 is welded to the container main body 101, and the state in which the opening 102 of the container main body 101 is sealed by the cover plate 110 is formed.

  As described above, in the method for manufacturing power storage element 10 according to the present embodiment, arch-shaped lid plate 110 that protrudes in a predetermined direction is pressed against opening 102 of container body 101 from the predetermined direction. Thus, a pressing process for expanding the lid plate 110, a welding process for welding the lid plate 110 expanded in the pressing process, and the container body 101 are included. The lid plate 110 according to the present embodiment is a lid plate 110 for closing the opening 102 which is a planar opening of the container main body 101 included in the container 100 of the power storage element 10, and is on the opposite side to the container main body 101. It can be expressed as a convex arch.

  In the present embodiment, an opening 102 is provided in the upper part of the container main body 101, and the arch-shaped lid plate 110 that protrudes upward is pressed from above, so that the container 102 is pushed and flattened according to the opening 102. In this state, the cover plate 110 and the container body 101 are welded.

  That is, due to the elastic force of the cover plate 110, both ends of the arched cover plate 110 are pressed against the container main body 101, and a repulsive force is generated in the middle portion of the cover plate 110 to move upward. As a result, it is possible to prevent the intermediate portion of the lid plate 110 from being excessively pressed against the container main body 101. Thereby, when welding the intermediate part of the cover board 110 and the container main body 101, the environment where it is easy to escape the gas in the molten metal is formed, As a result, generation | occurrence | production of a blowhole is suppressed.

  In addition, since both ends of the lid plate 110 are pressed against the container body 101 by elastic force when the intermediate portion of the lid plate 110 is pressed, the displacement of the lid plate 110 or one of the lid plates 110 is welded. The problem that the part floats from the container main body 101 hardly occurs. As a result, both ends of the lid plate 110 are also appropriately welded to the container main body 101.

  Here, if the opening 102 of the container main body 101 is closed with a flat lid plate, in reality, the lid plate may be randomly distorted. In order to correct this distortion, the container main body 101 When welding with, it is necessary to hold the entire lid plate with a relatively large force. This is a cause of blowholes.

  However, in the present embodiment, the cover plate 110 is pushed and expanded so as to have a shape corresponding to the opening 102 of the container body 101 by pressing an intermediate portion of the upwardly convex arch-shaped cover plate 110. Thereby, for example, the distance (including the case of 0) between the cover plate 110 and the container main body 101 is extended over the entire periphery of the cover plate 110 without pressing the entire cover plate 110 with a large force. The distance can be suitable for welding.

  As described above, according to the method for manufacturing power storage device 10 according to the present embodiment, power storage device 10 including container 100 in which container body 101 and lid plate 110 are joined by welding, and high-quality power storage. The element 10 can be manufactured.

  In the present embodiment, the cover plate 110 is provided with a gas discharge valve 170 at an intermediate portion that is a portion between both ends in the longitudinal direction.

  As described above, the gas discharge valve 170 is formed, for example, by thinning a part of the metal plate that is the material of the cover plate 110, and therefore, the gas discharge valve 170 is arranged in the cover plate 110. It can be said that it is a part with low rigidity.

  On the other hand, in the present embodiment, as described above, there is a possibility of occurrence of defects such as poor welding at the welding portion between the intermediate portion of the arch-shaped lid plate 110 that is pressed in the pressing step and the container main body 101. This reduces, for example, the bonding strength. As a result, it is possible to improve the resistance against the internal pressure of the container 100 at the intermediate portion of the lid plate 110 whose rigidity has been lowered by the gas discharge valve 170 being arranged. This is important from the viewpoint of ensuring the normal operation of the gas discharge valve 170, for example.

  In the manufacturing method of power storage device 10 according to the present embodiment, more specifically, in the pressing step, the end portion in the longitudinal direction of lid plate 110 moves from the inside of opening 102 toward the periphery. The effect of this will be described with reference to FIG.

  FIG. 8 is a diagram illustrating the details of a part of the pressing step included in the method for manufacturing power storage device 10 according to the embodiment. In FIG. 8, elements inside the container body 101 are shown by dotted lines.

  As described above, the cover plate 110 according to the present embodiment has an upwardly convex arch shape, and is designed and manufactured to a size that can close the opening 102 of the container body 101 while being pressed in the pressing process. ing. Therefore, the length of the cover plate 110 in the longitudinal direction (X-axis direction in the present embodiment) before the pressing step is smaller than the width of the container body 101 in the X-axis direction. More specifically, the width in the X-axis direction of the fitting portion 118 of the lid plate 110 fitted into the opening 102 of the container body 101 before the pressing step is the width of the opening 102 of the container body 101 in the X-axis direction. It is smaller than (the distance between the inner surfaces 102a facing each other in the X-axis direction).

  Therefore, for example, as shown in FIGS. 4 and 5 described above, when the lid plate 110 is disposed with respect to the container main body 101, the X axis direction center of the lid plate 110 and the X axis direction of the container main body 101 are arranged. It arrange | positions so that a center may correspond substantially, and a pressing process is made after that.

  Therefore, as shown in FIGS. 8A and 8B, the end portion 111 of the cover plate 110 is pressed from the inside of the opening 102 to the peripheral edge 102b of the opening 102 (the upper end of the inner surface 102a). ) Thereby, generation | occurrence | production of the foreign material by the corner | angular part 118a in the fitting part 118 of the cover plate 110 and the periphery 102b of the opening 102 colliding is suppressed.

  Here, if it is arranged so that the opening 102 of the container main body 101 is closed with a flat lid plate, the corner portion of the fitting portion of the lid plate moves from above toward the peripheral edge 102 b of the opening 102. Therefore, there is a possibility that the corner portion of the fitting portion and the peripheral edge 102b of the opening 102 collide with each other. Moreover, since the corner | angular part of a fitting part and the peripheral edge 102b of the opening 102 are all the corner | angular parts of a plate-shaped member, when these collide, it will be easy to chip out together. That is, when the flat lid plate is arranged so as to close the opening 102 of the container body 101, the lid plate or the container body 101 may be chipped, that is, a minute metal piece as a foreign object may be generated. There is. Such a minute metal piece also causes an internal short circuit in the electrode body 400, for example. Further, by reducing the size of the fitting portion of the cover plate in a plan view (when viewed from the positive side in the Z-axis direction), it is possible to avoid collision between the peripheral edge 102b of the opening 102 and the corner portion of the fitting portion. Although considered, such a measure is not realistic from the viewpoint of position control of the cover plate with respect to the container body 101.

  In this regard, in the present embodiment, when the lid plate 110 is arranged with respect to the container main body 101, as shown in FIG. 8A, the corner portion 118a of the fitting portion 118 of the lid plate 110. Is placed at a position away from the peripheral edge 102b of the opening 102 of the container body 101 in the X-axis direction. Therefore, when the lid plate 110 is arranged with respect to the container main body 101, generation of minute metal pieces due to collision of metal members is suppressed.

  Thereafter, as described above, the intermediate portion of the lid plate 110 is pressed, so that the shape of the lid plate 110 is made flat along the opening 102. At this time, as shown in FIGS. 8A and 8B, the corner portion 118a of the fitting portion 118 of the lid plate 110 moves from the inside of the opening 102 of the container body 101 toward the peripheral edge 102b. 8A and 8B, the left end portion 111 of the cover plate 110 is illustrated, but the right end portion of the cover plate 110 is similarly located inside the opening 102 of the container body 101. To the right edge. In this way, the lid plate 110 that has been spread out is prevented from being displaced from the normal position by the fitting portion 118 of the lid plate 110 coming into contact with the inner surface 102a of the container body 101. Thereafter, as described with reference to FIG. 7, the lid plate 110 and the container body 101 are welded.

(Other embodiments)
The power storage element according to the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiment. Unless it deviates from the gist of the present invention, various modifications conceived by those skilled in the art have been applied to the above-described embodiments, or forms constructed by combining a plurality of the constituent elements described above are within the scope of the present invention. include.

  For example, the lid plate 110 according to the above-described embodiment has an arch shape in which an intermediate portion in the longitudinal direction (X-axis direction) protrudes from both end portions. However, the cover plate included in the electricity storage element 10 may have an arch shape in which the intermediate portion in the short direction (Y-axis direction) protrudes from both ends in the state before the pressing step. Further, the lid plate 110 may not be substantially rectangular in plan view. For example, in plan view, a cover plate having a shape other than a substantially rectangular shape such as an ellipse, a circle, an oval, or a polygon other than a rectangle may be employed as the cover plate included in the power storage element.

  That is, if it is an arch-shaped cover plate convex on the side opposite to the container main body, the cover plate can be expanded by pressing the cover plate toward the container main body in the pressing step. As a result, as described with reference to FIG. 6, it is possible to create an appropriate pressing state at the portion where the lid plate and the container body are brought together by using the elastic force (spring force) generated in the lid plate. Thereby, generation | occurrence | production of the blowhole in the welding part of a cover plate and a container main body is suppressed.

  Further, it is not essential that the gas discharge valve 170 is disposed in the middle portion of the lid plate 110. It can also be said that the intermediate portion in the longitudinal direction of the long lid plate 110 is a portion that easily undergoes displacement or deformation due to the internal pressure when the internal pressure of the container 100 rises. Therefore, even when the gas discharge valve 170 is not present in the intermediate portion of the cover plate 110, as described above, by obtaining sufficient bonding strength in the intermediate portion, the reliability of the power storage element 10 as a whole is improved. Be improved.

  Further, the electrode terminals (200, 300) may not be disposed on the lid plate 110. That is, the electrode terminals (200, 300) may be arranged on any of the five surfaces of the container body 101. Even in this case, effects such as suppression of occurrence of blow holes due to the arch shape of the lid plate 110 before the pressing step are exhibited.

  Further, there is no particular limitation on the posture of the wound electrode body 400 included in the power storage element 10. For example, the winding shaft may be accommodated in the container body 101 in a posture that is parallel to the longitudinal direction (X-axis direction) of the lid plate 110.

  In addition, the electrode body included in the electricity storage element 10 does not have to be a wound type. The power storage element 10 includes, for example, a stacked electrode body in which flat electrode plates are stacked, or an electrode body having a structure in which long strip-shaped electrode plates are stacked in a bellows shape by repeating mountain folding and valley folding. Also good.

  In addition, the present invention can be realized not only as the power storage element described above but also as a cover plate included in the power storage element.

  The present invention is applicable to power storage elements such as lithium ion secondary batteries.

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Container 101 Container main body 102 Opening 102a Inner surface 102b Periphery 110 Cover plate 110a, 110b Through-hole 111 End part 118 Fitting part 118a Corner part 125, 135 Gasket 170 Gas exhaust valve 200 Positive electrode terminal 300 Negative electrode terminal

Claims (4)

A method for producing an electricity storage device comprising a container having a container body and a cover plate,
A pressing step of expanding the lid plate by pressing the arch-shaped lid plate convex toward the predetermined direction against the opening of the container body from the predetermined direction;
A method for manufacturing an electricity storage element, comprising: a lid plate that is spread in the pressing step; and a welding step that welds the container body. The method for manufacturing a power storage element according to claim 1, wherein a gas discharge valve is arranged in an intermediate portion that is a portion between both end portions in the longitudinal direction of the lid plate. 3. The at least one end portion in the longitudinal direction of the lid plate moves from the inside of the opening toward the periphery of the opening when the lid plate is pressed in the pressing step. 4. A method for manufacturing a storage element. A lid plate for closing the planar opening of the container body of the container of the storage element,
A cover plate for a container of an electricity storage element, which has a convex arch shape facing away from the container body.

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