Storage element

Abstract

The present invention provides an electric storage element, the electric storage element (10) comprising: a container (100) having a container body (120) and a cover body (110); and electrode terminals (positive terminal (200), negative terminal (300)) fixed to the cover body (110), wherein a joint (130) between the container body (120) and the cover body (110) is formed on the surface of the container (100) on the electrode terminal side, and the cover body (110) has: a recess (111-118) which is not arranged between the electrode terminal and the joint (130) but is arranged along the joint (130) at a position adjacent to the joint (130).

Description

Technical Field

[0001] The present invention relates to an electric storage device including a container having a container body and a cover. Background Art

[0002] Conventionally, a storage element is known that includes a container having a container body and a cover body, and the cover body is joined to the container body. For example, Patent Document 1 discloses a storage element (rectangular secondary battery) having a structure in which a cover body (battery cover) is welded to a container body (battery can) so that a welded portion is formed all around the outer peripheral end of the cover body, and the cover body seals the opening of the container body.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2014 / 033906 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the above-mentioned conventional power storage element, the power storage element may not be configured with high accuracy.

[0008] An object of the present invention is to provide an electric storage element that can be configured with high precision.

[0009] Means for solving problems

[0010] A storage element according to one embodiment of the present invention comprises: a container having a container body and a cover body; and an electrode terminal fixed to the cover body, wherein a joining portion between the container body and the cover body is formed on a surface of the container on the electrode terminal side, and the cover body comprises: a recessed portion which is not arranged between the electrode terminal and the joining portion but is arranged along the joining portion at a position adjacent to the joining portion.

[0011] The present invention can be realized not only as an electric storage element but also as a container provided in the electric storage element or a cover of the container.

[0012] Effects of the Invention

[0013] According to the present invention, the electric storage device can be configured with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a perspective view showing the appearance of the electric storage element according to the embodiment.

[0015] Figure 2 This is an exploded perspective view showing each component included in the electric storage device according to the embodiment in an exploded manner.

[0016] Figure 3 It is a perspective view showing the structure of the cover body according to the embodiment.

[0017] Figure 4 It is a top view and a cross-sectional view which show the structure when the cover body concerning embodiment is joined to a container main body.

[0018] Figure 5 It is a cross-sectional view showing a structure when the cover body according to Modification 1 of the embodiment is joined to the container body.

[0019] Figure 6 It is a cross-sectional view showing a structure in which a lid body according to Modification 2 of the embodiment is joined to a container body.

[0020] Figure 7 It is a cross-sectional view showing a structure in which a lid body according to Modification 3 of the embodiment is joined to a container body. DETAILED DESCRIPTION

[0021] The inventor of the present application has found that when the cover is joined to the container body, if the first side of the outer periphery of the cover is joined to the container body, a deviation may occur between the second side of the cover opposite to the first side and the container body. For example, in the case where the cover is joined to the container body by welding as in the above-mentioned storage element described in Patent Document 1, if the first side of the outer periphery of the cover is welded to the container body, the second side of the cover opposite to the first side may float due to the shrinkage caused by the solidification of the welded part. By other joining methods, a deviation may sometimes occur between the second side of the cover and the container body. In such a case, it may be impossible to join the second side of the cover to the container body with good accuracy, or the cover may be fixed in a tilted state so that the flatness of the cover cannot be ensured. In this way, in the above-mentioned conventional storage element, the storage element may not be constructed with good accuracy.

[0022] A storage element according to one embodiment of the present invention comprises: a container having a container body and a cover body; and an electrode terminal fixed to the cover body, wherein a joining portion between the container body and the cover body is formed on a surface of the container on the electrode terminal side, and the cover body comprises: a recessed portion which is not arranged between the electrode terminal and the joining portion but is arranged along the joining portion at a position adjacent to the joining portion.

[0023] Thus, in the electric storage element, a joint between the container body and the cover body is formed on the surface on the electrode terminal side of the container, and the cover body has a recessed portion, which is not arranged between the electrode terminal and the joint portion, but is arranged along the joint portion at a position adjacent to the joint portion. In this way, a recessed portion along the joint portion is formed near the joint portion of the cover body, so even if the cover body tilts when the first side of the cover body is joined to the container body, the tilt of the cover body can be absorbed by the recessed portion along the joint portion, thereby suppressing the tilt of the cover body. On the other hand, if a recessed portion is formed on the side of the position where the electrode terminal is arranged on the cover body (between the electrode terminal and the joint portion), a force is applied to the cover body during the processing of the recessed portion, which may result in the inability to ensure the flatness of the surface of the cover body where the electrode terminal is arranged. Therefore, by not forming a recessed portion on the side of the electrode terminal (between the electrode terminal and the joint portion), the flatness of the surface of the cover body where the electrode terminal is arranged can be ensured. Through these structures, the electric storage element can be constructed with good precision.

[0024] The cover may further include a gas exhaust valve, and the recessed portion may be arranged at a position that does not overlap with the gas exhaust valve when viewed from a direction in which the recessed portion extends.

[0025] Thus, the recess formed in the cover body is arranged at a position that does not overlap with the gas exhaust valve when viewed from the extension direction of the recess. If the recess is arranged at a position that overlaps with the gas exhaust valve when viewed from the extension direction of the recess (a position that intersects with the gas exhaust valve if the recess is extended), it is possible to affect the opening pressure (working pressure) of the gas exhaust valve. Therefore, by arranging the recess at a position that does not overlap with the gas exhaust valve when viewed from the extension direction, the recess can suppress the influence on the opening pressure of the gas exhaust valve. Thus, the storage element can be constructed with good precision.

[0026] The recessed portion may be arranged at a position different from a position between the gas exhaust valve and the joint portion.

[0027] Thus, the recess formed in the cover body is arranged at a position different from that between the gas exhaust valve and the joint. Generally, the gas exhaust valve is formed by thinning the thickness of the cover body, so if a recess is formed on the side of the gas exhaust valve (between the gas exhaust valve and the joint), it is possible to affect the processing accuracy of the gas exhaust valve. Therefore, by not forming a recess on the side of the gas exhaust valve, the processing accuracy of the gas exhaust valve can be ensured. Thus, the storage element can be constructed with good precision.

[0028] The recessed portion may be formed on the outer surface of the cover body, and a protrusion extending along the recessed portion may be formed on the inner surface of the cover body.

[0029] Thus, the recessed portion formed in the cover is formed on the outer surface of the cover, and a protrusion extending along the recessed portion is formed on the inner surface of the cover. For example, when the outer surface of the cover is recessed to form the recessed portion, the inner surface of the cover can be protruded to form the protrusion along the recessed portion. Thus, by using the protrusion to position the cover and the container body, the cover can be positioned on the container body and then joined, so that the storage element can be formed with good accuracy.

[0030] The recessed portion may be formed by a groove portion extending along the joining portion.

[0031] Thus, the recessed portion formed in the cover body is formed by the groove portion extending along the joint portion. Thus, the recessed portion can be easily formed by processing the groove portion extending along the joint portion in the cover body. Thus, the storage element can be easily formed with good accuracy.

[0032] The recessed portion may be arranged at a position overlapping with an internal space of the container when viewed from a normal direction of an outer surface of the lid.

[0033] Thus, the recessed portion formed in the cover is arranged at a position overlapping with the internal space of the container when viewed from the normal direction of the outer surface of the cover. Thus, by arranging the recessed portion at a position overlapping with the internal space of the container, the recessed portion can easily absorb the tilt of the cover when the container body and the cover are joined. Thus, the storage element can be formed with good accuracy.

[0034] Hereinafter, the storage element involved in the embodiment (and its variant) of the present invention will be described with reference to the accompanying drawings. The embodiments described below all show general or specific examples. The numerical values, shapes, materials, components, configuration positions and connection methods of the components, manufacturing processes, and the order of the manufacturing processes shown in the following embodiments are examples, and their main purpose is not to limit the present invention. Among the components in the following embodiments, the components that represent the highest concept and are not recorded in the independent claims are described as arbitrary components. In the figures, dimensions, etc. are not strictly illustrated.

[0035] In the description and drawings of the following embodiments, the arrangement direction of a pair of electrode terminals (positive terminal and negative terminal) of the storage element, the arrangement direction of a pair of collectors (positive collector and negative collector), the opposing direction of the short side of the container, or the extending direction (long side direction) of the cover of the container is defined as the X-axis direction. The opposing direction of the long side of the container, the short side direction of the short side of the container, the short side direction of the cover of the container, or the thickness direction of the container is defined as the Y-axis direction. The arrangement direction of the container body and the cover of the storage element, the thickness direction of the cover, the long side direction of the short side of the container, or the up and down direction is defined as the Z-axis direction. These X-axis directions, Y-axis directions, and Z-axis directions are directions that intersect each other (orthogonal in this embodiment). It is also conceivable that the Z-axis direction does not become the up and down direction depending on the usage mode, but for the sake of convenience of description, the Z-axis direction is described as the up and down direction. In the following description, for example, the positive side of the X-axis direction represents the arrow direction side of the X-axis, and the negative side of the X-axis direction represents the side opposite to the positive side of the X-axis direction. The same applies to the Y-axis direction and the Z-axis direction.

[0036] (Implementation Method)

[0037] [1 Comprehensive Description of the Electric Storage Element 10]

[0038] First, use Figure 1 as well as Figure 2 The energy storage element 10 in this embodiment will be fully described. Figure 1 It is a perspective view showing the appearance of the electric storage element 10 according to the present embodiment. Figure 2 This is an exploded perspective view showing the components of the electric storage device 10 according to the present embodiment in an exploded manner.

[0039] The storage element 10 is a secondary battery that can charge and discharge electricity, specifically a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The storage element 10 is used in a power source for a car such as an electric vehicle (EV), a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV), a power source for an electronic device, or a power source for power storage, etc. The storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and can be a secondary battery other than a non-aqueous electrolyte secondary battery, or a capacitor. The storage element 10 may also be a primary battery that can use the stored electricity even if the user does not charge it instead of a secondary battery. The storage element 10 may also be a battery using a solid electrolyte. In the present embodiment, although a storage element 10 in the shape of a rectangular parallelepiped (square) is illustrated, the shape of the storage element 10 is not limited to a rectangular parallelepiped shape, and can be a cylindrical shape or a long cylindrical shape, etc., and can also be a laminated storage element.

[0040] like Figure 1As shown, the electric storage element 10 includes: a container 100 having a cover 110 and a container body 120; a positive electrode terminal 200; and a negative electrode terminal 300. Figure 2 As shown, the electrode body 400 , the positive electrode current collector 500 , and the negative electrode current collector 600 are accommodated inside the container 100 .

[0041] Gaskets and the like are provided between the cover 110 and the positive terminal 200, and between the cover 110 and the positive electrode collector 500, in order to improve insulation and airtightness, but these components are omitted in the drawings. The same is true for the negative electrode side. An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but the illustration is omitted. As for the electrolyte, there is no particular restriction on its type as long as it does not damage the performance of the storage element 10, and a variety of electrolytes can be selected. In addition to the above-mentioned components, there may be a separator provided on the side of the positive electrode collector 500 and the negative electrode collector 600, a liquid injection portion for injecting an electrolyte into the container 100, or an insulating film that wraps the electrode body 400 and the like inside.

[0042] The container 100 is a rectangular parallelepiped (square) shell having a container body 120 with an opening formed therein and a cover 110 that closes the opening of the container body 120. The container body 120 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 100, and has two flat and rectangular long side surfaces on the sides of the Y-axis direction, two flat and rectangular short side surfaces on the sides of the X-axis direction, and a flat and rectangular bottom surface on the negative side of the Z-axis direction. The cover 110 is a flat and rectangular member that extends in the X-axis direction and constitutes the cover of the container 100, and is disposed on the positive side of the container body 120 in the Z-axis direction.

[0043] Specifically, after the electrode body 400 and the like are accommodated in the container body 120, the container body 120 and the cover body 110 are joined by welding or the like to form a joint 130, thereby forming a sealed structure inside. That is, a joint 130 where the container body 120 and the cover body 110 are joined to each other is formed on the side of the container 100 (the surfaces on both sides of the X-axis direction and the surfaces on both sides of the Y-axis direction). The material of the container 100 (the container body 120 and the cover body 110) is not particularly limited, but is preferably a metal that can be welded (joined) such as stainless steel, aluminum, aluminum alloy, iron, or a plated steel plate. The cover body 110 and the container body 120 are preferably formed of the same material, but may also be formed of different materials.

[0044] The cover 110 is provided with a gas discharge valve 110a in the central portion, an opening 110b at the end on the positive side in the X-axis direction, and an opening 110c at the end on the negative side in the X-axis direction. The gas discharge valve 110a is a portion (safety valve) that releases the pressure inside the container 100 when the pressure inside the container 100 rises. That is, the gas discharge valve 110a has a thin-walled portion, and when the pressure inside the container 100 reaches a given opening pressure, the thin-walled portion ruptures and opens, thereby releasing the pressure inside the container 100. The openings 110b and 110c are circular through holes for mounting the positive terminal 200 and the negative terminal 300 on the cover 110. A more detailed description of the structure of the cover 110 will be described later.

[0045] The electrode body 400 is an electric storage element (electricity generation element) that has a positive electrode plate, a negative electrode plate, and a separator and can store electric power. The positive electrode plate is a plate having a positive electrode active material layer formed on a long strip-shaped collector foil, i.e., a positive electrode substrate layer, made of aluminum or an aluminum alloy. The negative electrode plate is a plate having a negative electrode active material layer formed on a long strip-shaped collector foil, i.e., a negative electrode substrate layer, made of copper or a copper alloy. The separator is a microporous sheet made of a resin or the like. The electrode body 400 is formed by placing a separator between the positive electrode plate and the negative electrode plate and winding them.

[0046] In the present embodiment, an oval shape is shown as the cross-sectional shape of the electrode body 400, but it may also be an elliptical shape, a circular shape, a polygonal shape, etc. The electrode body 400 may be as follows: Figure 2 The shape may be wound with the X-axis direction as the winding axis, or may be wound with the Z-axis direction as the winding axis. It may also be a stacked type with stacked flat plates, or a corrugated type with the plates folded into a corrugated shape.

[0047] The positive terminal 200 is an electrode terminal electrically connected to the positive electrode plate of the electrode body 400, and the negative terminal 300 is an electrode terminal electrically connected to the negative electrode plate of the electrode body 400. That is, the positive terminal 200 and the negative terminal 300 are metal electrode terminals for extracting the power stored in the electrode body 400 to the external space of the storage element 10, and for introducing the power into the internal space of the storage element 10 in order to store the power in the electrode body 400. The positive terminal 200 and the negative terminal 300 are attached to the cover 110 arranged above the electrode body 400.

[0048] Specifically, Figure 2As shown, the positive terminal 200 has a shaft portion 210, and the shaft portion 210 is inserted into the opening portion 110b of the cover 110 and the opening portion 510 of the positive electrode collector 500 and is riveted, thereby being fixed to the cover 110 together with the positive electrode collector 500. Similarly, the negative terminal 300 has a shaft portion 310, and the shaft portion 310 is inserted into the opening portion 110c of the cover 110 and the opening portion 610 of the negative electrode collector 600 and is riveted, thereby being fixed to the cover 110 together with the negative electrode collector 600. That is, the positive terminal 200 and the negative terminal 300 are fixed to the cover 110 in a state where they penetrate the cover 110. Figure 2 In the figure, the shaft portion 210 and the shaft portion 310 are shown in the shape before being riveted.

[0049] The positive electrode collector 500 and the negative electrode collector 600 are conductive and rigid members disposed between the electrode body 400 and the side surface of the container 100, and electrically connected to the positive electrode terminal 200 and the negative electrode terminal 300 and the positive electrode plate and the negative electrode plate of the electrode body 400. The material of the positive electrode collector 500 is not limited, but is formed of aluminum or an aluminum alloy, etc., as is the positive electrode substrate layer of the electrode body 400. The material of the negative electrode collector 600 is also not limited, but is formed of copper or a copper alloy, etc., as is the negative electrode substrate layer of the electrode body 400.

[0050] [2. Detailed description of the structure of the cover body 110]

[0051] Next, the structure of the cover body 110 will be described in detail. Figure 3 1 is a perspective view showing the structure of the cover 110 according to the present embodiment. Specifically, Figure 3 (a) is to Figure 2 The structure of the cover 110 is enlarged and shown in a three-dimensional diagram, Figure 3 (b) is to Figure 2 A perspective view showing an enlarged structure of the back side (the surface on the negative side in the Z-axis direction) of the cover body 110 in FIG. Figure 4 1 is a top view and a cross-sectional view showing a structure in which the cover 110 according to the present embodiment is joined to the container body 120. Specifically, Figure 4 (a) shows the Z-axis direction from the positive side Figure 1 A top view of the structure of the case of the power storage element 10, Figure 4 (b) shows that Figure 4 1 is a cross-sectional view of the structure when the cover body 110 and the container body 120 in (a) are cut along the IVb-IVb cross section.

[0052] As shown in these figures, the cover 110 has bulging portions 110d and 110e, an outer peripheral portion 110f, recessed portions 111 to 118, and protrusions 111a to 118a in addition to the above-mentioned gas discharge valve 110a and openings 110b and 110c.

[0053] [2.1 Description of Structures Other than Recesses 111 to 118 and Protrusions 111 a to 118 a]

[0054] As described above, the gas discharge valve 110a is arranged at the central position of the cover body 110 (the central position in the X-axis direction and the central position in the Y-axis direction). In the present embodiment, the gas discharge valve 110a is formed integrally with the cover body 110. That is, the cover body 110 formed with the gas discharge valve 110a can be manufactured by pressing a plate material or the like. Therefore, the gas discharge valve 110a is formed of the same material as the cover body 110. The gas discharge valve 110a can also be composed of an individual that is originally separated from the cover body 110. For example, an opening portion can also be formed at the central position of the cover body 110, and the gas discharge valve 110a can be embedded in the opening portion, and joined to the cover body 110 by welding or the like, thereby being arranged at the central position of the cover body 110. In this case, the material of the gas discharge valve 110a is not particularly limited, but can be formed of aluminum, aluminum alloy, iron, copper, copper alloy, stainless steel, plated steel plate, copper-plated material, clad steel (Fe-Ni, Ni-Cu, Al-Ni), etc.

[0055] The bulges 110d and 110e are rectangular portions in a plan view (viewed from the Z-axis direction) arranged at a position sandwiching the gas discharge valve 110a in the X-axis direction, and have a shape in which the outer surface of the cover body 110 is recessed and the inner surface of the cover body 110 is protruding. Specifically, the bulge 110d is arranged on the side of the positive side of the gas discharge valve 110a in the X-axis direction, and is extended in the Y-axis direction and arranged to cover the side of the gas discharge valve 110a. The bulge 110e is arranged on the side of the negative side of the gas discharge valve 110a in the X-axis direction, and is extended in the Y-axis direction and arranged to cover the side of the gas discharge valve 110a. According to such a structure, the bulges 110d and 110e strengthen the strength of the side of the gas discharge valve 110a, and seek to stabilize the opening pressure of the gas discharge valve 110a.

[0056] As described above, the openings 110b and 110c are through holes for mounting the positive electrode terminal 200 and the negative electrode terminal 300. That is, the positive electrode terminal 200 is mounted in the rectangular terminal mounting region R1 around the opening 110b, and the negative electrode terminal 300 is mounted in the rectangular terminal mounting region R2 around the opening 110c.

[0057] The outer peripheral portion 110f is a step-shaped portion formed on the outer peripheral portion of the cover 110. Specifically, the outer peripheral portion 110f is an annular portion formed over the entire circumference of the outer peripheral portion of the cover 110, and is a thin-walled portion due to the concavity of the inner surface. The outer peripheral portion 110f is a portion that contacts the container body 120 when the cover 110 is placed on the container body 120. That is, Figure 4 As shown, in the joining of the cover body 110 and the container body 120 , the outer peripheral portion 110 f and the container body 120 are joined, thereby forming the joining portion 130 .

[0058] [2.2 Description of the structure of the recessed portions 111 to 118]

[0059] The recesses 111 to 118 are recesses (recesses that are recessed in the outer surface) formed on the outer surface (the surface on the positive side in the Z-axis direction) of the cover body 110, and are arranged to extend along the outer peripheral portion 110f at a position adjacent to the outer peripheral portion 110f. Specifically, the recesses 111 to 118 are formed by groove portions extending along the outer peripheral portion 110f. In the present embodiment, the cross-section of the recesses 111 to 118 (the cross-section when cut along the YZ plane) has a rectangular shape, but the cross-sectional shape of the recesses 111 to 118 may also be a triangle, a trapezoid, other polygonal shapes, a semicircle, a semi-ellipse, a semi-circle, etc., without particular limitation.

[0060] As described above, the outer peripheral portion 110f is provided with the joint 130 between the container body 120 and the lid body 110. Figure 4 As shown in (b), for example, by irradiating a laser from the side of the container 100, a joint 130 where the container body 120 and the peripheral portion 110f are welded is formed on the side of the container 100. Therefore, the recesses 111 to 118 are arranged along the joint 130 at a position adjacent to the joint 130. The recesses 111 to 118 are formed by grooves extending along the joint 130. That is, the recesses 111, 113, 115 and 117 are grooves extending along the joint 130 of the peripheral portion 110f formed on the positive side of the cover body 110 in the Y-axis direction, and the recesses 112, 114, 116 and 118 are grooves extending along the joint 130 of the peripheral portion 110f formed on the negative side of the cover body 110 in the Y-axis direction.

[0061] like Figure 3 As shown, the recesses 111 to 118 are arranged at positions that do not overlap with the terminal mounting regions R1 and R2 when viewed from the extending direction of the recesses 111 to 118 (in the X-axis direction in this embodiment). The terminal mounting regions R1 and R2 are regions where the positive terminal 200 and the negative terminal 300 are mounted. Figure 4As shown, the recesses 111 to 118 are arranged at positions that do not overlap with the electrode terminals (positive terminal 200 and negative terminal 300) when viewed from the extending direction (X-axis direction) of the recesses 111 to 118. For example, the recesses 111 and 112 are arranged at positions that do not intersect with the positive terminal 200 (and the terminal mounting region R1) even when extended to the positive side in the X-axis direction. The recesses 113 and 114 are arranged at positions that do not intersect with the negative terminal 300 (and the terminal mounting region R2) even when extended to the negative side in the X-axis direction.

[0062] The recesses 111 to 118 are arranged at positions that do not overlap with the gas discharge valve 110a and the bulging portions 110d and 110e when viewed from the extending direction of the recesses 111 to 118 (the X-axis direction in this embodiment). For example, the recesses 115 and 116 are arranged at positions that do not intersect with the gas discharge valve 110a even when extended to the negative side of the X-axis direction, and the recesses 117 and 118 are arranged at positions that do not intersect with the gas discharge valve 110a even when extended to the positive side of the X-axis direction. The recesses 111 and 112 are arranged at positions that do not intersect with the bulging portion 110d even when extended to the negative side of the X-axis direction, and the recesses 115 and 116 are arranged at positions that do not intersect with the bulging portion 110d even when extended to the positive side of the X-axis direction. The same applies to the bulging portion 110e side.

[0063] Furthermore, if Figure 3 As shown in FIG. 1 , the recesses 111 to 118 are arranged at positions different from those between the terminal mounting regions R1 and R2 and the outer peripheral portion 110 f. Figure 4 As shown, the recesses 111 to 118 are not arranged between the electrode terminal (positive terminal 200 and negative terminal 300) and the joint 130, but are arranged at a position different from that between the electrode terminal and the joint 130. For example, the recess 111 does not extend between the positive terminal 200 (and the terminal mounting area R1) and the joint 130 (and the peripheral portion 110f) on the positive side of the Y-axis direction. The recess 112 does not extend between the positive terminal 200 (and the terminal mounting area R1) and the joint 130 (and the peripheral portion 110f) on the negative side of the Y-axis direction. The same is true for the negative terminal 300 side.

[0064] like Figure 3 As shown in FIG. 1 , the recesses 111 to 118 are arranged at positions different from the gas discharge valve 110a and the bulging portions 110d and 110e and the outer peripheral portion 110f. Figure 4As shown, the recesses 111 to 118 are arranged at positions different from those between the gas discharge valve 110a and the bulging portions 110d and 110e and the joint portion 130. For example, the recess 115 is not extended between the gas discharge valve 110a and the joint portion 130 (and the peripheral portion 110f) on the positive side in the Y-axis direction, and the recess 116 is not extended between the gas discharge valve 110a and the joint portion 130 (and the peripheral portion 110f) on the negative side in the Y-axis direction. The same is true for the recesses 117 and 118. The recesses 111 and 115 are not extended between the bulging portion 110d and the joint portion 130 (and the peripheral portion 110f) on the positive side in the Y-axis direction, and the recesses 112 and 116 are not extended between the bulging portion 110d and the joint portion 130 (and the peripheral portion 110f) on the negative side in the Y-axis direction. The same is true for the bulging portion 110e side.

[0065] like Figure 4 As shown, the recesses 111 to 118 are arranged at positions overlapping with the internal space of the container 100 when viewed from the normal direction of the outer surface of the lid 110. That is, the recesses 111 to 118 are arranged in the space ( Figure 4 ) is directly above the internal space S) shown in (b), and is thus configured at a position overlapping with the internal space S when viewed from the Z-axis direction.

[0066] In the present embodiment, the recesses 111 to 118 are arranged at positions that are line-symmetrical with respect to the center line of the cover body 110 in the X-axis direction and the Y-axis direction, and point-symmetrical with respect to the center position of the cover body 110, but the arrangement positions and shapes of the recesses 111 to 118 are not particularly limited as long as they meet the above requirements. For example, the recess 111 or 112 may be slightly moved or extended to the positive side of the X-axis direction, or may be composed of a plurality of grooves arranged in the X-axis direction, or may be slightly widened in the Y-axis direction, or may be slightly inclined relative to the X-axis direction. The recesses 115, 116, etc. may not be provided. The bulging portion 110d may not be provided, and the recesses 111 and 115 may be integrated. The same is true for other recesses.

[0067] [2.3 Description of the structure of the protrusions 111a to 118a]

[0068] The protrusions 111a to 118a are protrusions (protrusions protruding from the inner surface) formed on the inner surface (the surface on the negative side in the Z-axis direction) of the cover body 110, and are arranged to extend along the recesses 111 to 118. Specifically, the protrusions 111a to 118a have the same length as the recesses 111 to 118, respectively, and are arranged to face the recesses 111 to 118, respectively. Thus, even if the recesses 111 to 118 are formed on the cover body 110, it is possible to suppress the thickness from being reduced.

[0069] That is, the protrusions 111a to 118a are arranged along the outer peripheral portion 110f at a position adjacent to the outer peripheral portion 110f, and abut against the upper end portion of the container body 120 from the inner surface. For example, the protrusion 111a is arranged along the outer peripheral portion 110f at the same position as the recess 111 in the Y-axis direction (the back side of the recess 111). It abuts against the inner surface of the upper end portion of the container body 120 on the positive side in the Y-axis direction from the negative side in the Y-axis direction. The protrusion 112a is arranged along the outer peripheral portion 110f at the same position as the recess 112 in the Y-axis direction (the back side of the recess 112), and abuts against the inner surface of the upper end portion of the container body 120 on the negative side in the Y-axis direction from the positive side in the Y-axis direction. The same is true for the other protrusions.

[0070] Such protrusions 111a to 118a can be formed when the recesses 111 to 118 are formed on the cover 110. For example, when the recesses 111 to 118 are formed by recessing the outer surface of the cover 110 by press working, the inner surface of the cover 110 at positions opposite to the recesses 111 to 118 are raised, thereby forming the protrusions 111a to 118a. The method of forming the protrusions 111a to 118a is not limited to the above method, and any processing can be performed to form the protrusions 111a to 118a.

[0071] The configuration position and shape of the protrusions 111a to 118a are not particularly limited. For example, the protrusion 111a or 112a may be slightly moved or extended to the positive side of the X-axis direction, or may be composed of a plurality of protrusions arranged in the X-axis direction, or may be slightly widened in the Y-axis direction, or may be slightly inclined relative to the X-axis direction. Protrusions 115a, 116a, etc. may not be provided. Protrusions 111a and 115a may also be integrated. The same is true for other protrusions. In the present embodiment, the cross-section of the protrusions 111a to 118a (the cross-section when cut in the YZ plane) has a rectangular shape, but the cross-sectional shape of the protrusions 111a to 118a may also be a triangle, a trapezoid, other polygonal shapes, a semicircle, a semi-ellipse, a semi-circle, etc., without particular limitation.

[0072] [3. Description of the Effect]

[0073] As described above, according to the energy storage element 10 involved in the embodiment of the present invention, a joint 130 between the container body 120 and the cover body 110 is formed in the container 100, and the cover body 110 has: recesses 111 to 118, which are not arranged between the electrode terminals (positive terminal 200 and negative terminal 300) and the joint 130, and are arranged along the joint 130 at a position adjacent to the joint 130.

[0074] In this way, the recessed portions 111 to 118 are formed along the joint portion 130 near the joint portion 130 of the cover 110. Therefore, even if the cover 110 tilts when the first side of the cover 110 is joined to the container body 120, the tilt of the cover 110 can be absorbed by the recessed portions 111 to 118 along the joint portion 130, and the tilt of the cover 110 can be suppressed. In particular, when the cover 110 is joined to the container body 120 by welding, the joint portion melts and shrinks, so that the cover 110 tilts relative to the container body 120, and the effect of forming the recessed portions 111 to 118 is strong. After joining, even if the container 100 repeatedly expands and contracts due to changes in the internal pressure of the container 100, the recessed portions 111 to 118 can absorb the force caused by the expansion and contraction of the container 100. When the internal pressure of the container 100 increases, the stress applied to the cover 110 can be relieved by the recessed portions 111 to 118 from being directly transmitted to the joint portion 130.

[0075] On the other hand, if a recess is formed on the side of the cover 110 where the electrode terminal is arranged (between the electrode terminal and the joint 130), a force is applied to the cover 110 during the processing of the recess, which may result in failure to ensure the flatness of the surface of the cover 110 where the electrode terminal is arranged. Therefore, by not forming the recesses 111 to 118 on the side of the electrode terminal (between the electrode terminal and the joint 130), the flatness of the surface of the cover 110 where the electrode terminal is arranged can be ensured. If the electrode terminal is fixed to the cover 110, even if the recesses 111 to 118 are not formed on the side of the electrode terminal, the bending, expansion, and contraction of the portion of the cover 110 where the electrode terminal is fixed can be suppressed. With these structures, the storage element 10 can be constructed with good precision.

[0076] The recesses 111 to 118 formed in the cover 110 are arranged at positions that do not overlap with the electrode terminals when viewed from the extending direction of the recesses. If the recesses 111 to 118 are arranged at positions that overlap with the electrode terminals when viewed from the extending direction of the recesses (positions that intersect with the electrode terminals when the recesses 111 to 118 are extended), the flatness of the surface of the cover 110 on which the electrode terminals are arranged may be affected. Therefore, by arranging the recesses 111 to 118 at positions that do not overlap with the electrode terminals when viewed from the extending direction, the recesses 111 to 118 can suppress the flatness of the surface of the cover 110 on which the electrode terminals are arranged. As a result, the storage element 10 can be constructed with good precision.

[0077] The recesses 111 to 118 formed in the cover body 110 are arranged at positions that do not overlap with the gas discharge valve 110a when viewed from the extending direction of the recesses. If the recesses 111 to 118 are arranged at positions that overlap with the gas discharge valve 110a when viewed from the extending direction of the recesses (positions that intersect with the gas discharge valve 110a when the recesses 111 to 118 are extended), it is possible to affect the opening pressure (operating pressure) of the gas discharge valve 110a. Therefore, by arranging the recesses 111 to 118 at positions that do not overlap with the gas discharge valve 110a when viewed from the extending direction, the recesses 111 to 118 can suppress the influence of the opening pressure of the gas discharge valve 110a. As a result, the storage element 10 can be constructed with good precision.

[0078] The recessed portions 111 to 118 formed in the cover 110 are arranged at a position different from the position between the gas discharge valve 110a and the joint 130. Generally, the gas discharge valve 110a is formed by reducing the thickness of the cover 110. Therefore, if the recessed portion is formed on the side of the gas discharge valve 110a (between the gas discharge valve 110a and the joint 130), it may affect the processing accuracy of the gas discharge valve 110a. Therefore, by not forming the recessed portions 111 to 118 on the side of the gas discharge valve 110a, the processing accuracy of the gas discharge valve 110a can be ensured. As a result, the storage element 10 can be constructed with good accuracy.

[0079] The recessed portions 111 to 118 formed in the cover 110 are formed on the outer surface of the cover 110, and the protrusions 111a to 118a extending along the recessed portions 111 to 118 are formed on the inner surface of the cover 110. That is, when the outer surface of the cover 110 is recessed to form the recessed portions 111 to 118, the inner surface of the cover 110 can be protruded to form the protrusions 111a to 118a along the recessed portions 111 to 118. Thus, by using the protrusions 111a to 118a for positioning the cover 110 and the container body 120, the cover 110 can be positioned on the container body 120 and then joined. When joining the cover 110 to the container body 120, by pressing the container body 120 at the position where the protrusions 111a to 118a are arranged, it is easy to press the welding part. With these structures, the storage element 10 can be formed with good accuracy.

[0080] The recesses 111 to 118 formed in the cover 110 are formed by grooves extending along the joint 130. Thus, the recesses 111 to 118 can be easily formed by processing the grooves extending along the joint 130 in the cover 110. Thus, the electric storage element 10 can be easily configured with high accuracy.

[0081] The recessed portions 111 to 118 formed in the cover 110 are arranged at positions overlapping with the internal space of the container 100 when viewed from the normal direction of the outer surface of the cover 110. In this way, since the recessed portions 111 to 118 are arranged at positions overlapping with the internal space of the container 100, the recessed portions 111 to 118 can easily absorb the tilt of the cover 110 when the container body 120 and the cover 110 are joined. After joining, the recessed portions 111 to 118 can easily absorb the force caused by the expansion and contraction of the container 100. Thus, the storage element 10 can be formed with good accuracy.

[0082] [Description of Modifications of 4 Embodiments]

[0083] (Variant 1)

[0084] Next, a modification 1 of the above-described embodiment will be described. Figure 5 1 is a cross-sectional view showing a structure in which the cover 140 according to the first modification of the present embodiment is joined to the container body 120. Figure 4 (b) The corresponding figure.

[0085] like Figure 5 As shown, in the cover 140 in this modification, the outer peripheral portion 110f of the cover 110 in the above embodiment is replaced with an outer peripheral portion 140f. The outer peripheral portion 140f is not a step-shaped portion (thin-walled portion) like the outer peripheral portion 110f in the above embodiment. Therefore, when the cover 140 is arranged on the container body 120, the outer peripheral portion 140f is deeply embedded in the inside of the container body 120, so the cover 140 in this modification does not have the protrusions 111a to 118a in the above embodiment. However, in this modification, the cover 140 may also have the same protrusions as the protrusions 111a to 118a in the above embodiment. That is, protrusions extending along the recesses 141, 142, etc. may be formed on the inner surface of the cover 140. The recesses 141, 142, etc. of the cover 140 in this modification have the same structure as the recesses 111, 112, etc. in the above embodiment.

[0086] In such a structure, the outer peripheral portion 140f of the cover 140 is embedded in the interior of the container body 120, and the container body 120 and the outer peripheral portion 140f are joined, forming a joint portion 131 on the upper surface of the container. That is, in the above-mentioned embodiment, the joint portion 130 is formed on the side surface of the container 100 by irradiating a laser or the like from the side of the container 100, but in this modified example, the joint portion 131 is formed on the upper surface of the container by irradiating a laser or the like from above the container. The other structures of this modified example are the same as those of the above-mentioned embodiment, and detailed descriptions are omitted.

[0087] Thus, in this modified example, the joint 131 of the container body 120 and the cover 140 is formed on the surface on the electrode terminal side of the container, and the cover 140 has recesses 141, 142, etc., which are not arranged between the electrode terminal and the joint 131, but are arranged along the joint 131 at a position adjacent to the joint 131. The cover 140 has a gas discharge valve (not shown), and the recesses 141, 142, etc. are arranged at a position that does not overlap with the gas discharge valve when viewed from the extending direction of the recesses 141, 142, etc., and are arranged at a position different from the position between the gas discharge valve and the joint 131. Furthermore, the recesses 141, 142, etc. are formed by grooves extending along the joint 131, and are arranged at a position that overlaps with the internal space of the container when viewed from the normal direction of the outer surface of the cover 140.

[0088] As described above, according to the storage element involved in this modification, even when the joint portion 131 is formed on the upper surface (the surface on the electrode terminal side) of the container, the cover 140 may be tilted when the container body 120 and the cover 140 are joined, so the same effect as the above embodiment can be exerted. In particular, when the joint portion 131 is formed on the upper surface of the container, the cover 140 tends to be easily tilted when the first side of the cover 140 is joined to the container body 120, so the effect in this modification is strong. In this modification, there is no need to process the outer peripheral portion 140f into a step shape or form the protrusions 111a to 118a as in the above embodiment, so the cover 140 can be easily manufactured.

[0089] (Variant 2)

[0090] Next, a second modification of the above-described embodiment will be described. Figure 6 2 is a cross-sectional view showing a structure in which the cover 150 according to the second modification of the present embodiment is joined to the container body 120. Figure 4 (b) The corresponding figure.

[0091] like Figure 6 As shown, in the cover 150 in this modification, the recesses 141, 142, etc. of the cover 140 in the above modification 1 are replaced with a recess 151, etc. The recess 151 is a recess formed by continuously recessing the outer surface of the cover 150 in the Y-axis direction from the position of the recess 141 in the above modification 1 to the position of the recess 142. The joint 132 in this modification has the same structure as the joint 131 in the above modification 1. The other structures of this modification are also the same as those of the above modification 1, and detailed descriptions are omitted.

[0092] As described above, according to the electric storage device according to this modification, it is possible to achieve the same effects as those of the above-mentioned modification 1. In particular, in this modification, the number of recessed portions to be formed can be reduced, so that the cover 150 can be easily manufactured.

[0093] (Variant 3)

[0094] Next, a modification 3 of the above-described embodiment will be described. Figure 7 1 is a cross-sectional view showing a structure in which the cover 160 according to the third modification of the present embodiment is joined to the container body 120. Figure 4 (b) The corresponding figure.

[0095] like Figure 7 As shown, in the cover 160 in this modification, the recesses 141, 142, etc. of the cover 140 in the above-mentioned modification 1 are replaced with recesses 161, 162, etc. The recess 161 is a recess (step portion) formed by continuously recessing the outer surface of the cover 160 in the Y-axis direction from the position of the recess 141 in the above-mentioned modification 1 to the edge on the positive side of the Y-axis direction of the cover 160. The recess 162 is a recess (step portion) formed by continuously recessing the outer surface of the cover 160 in the Y-axis direction from the position of the recess 142 in the above-mentioned modification 1 to the edge on the negative side of the Y-axis direction of the cover 160. As a result, the cover 160 has a thin-walled outer peripheral portion 160f, and a joint portion 133 is formed where the outer peripheral portion 160f and the container body 120 are joined. The other structures of this modification are the same as those of the above-mentioned modification 1, and detailed descriptions are omitted.

[0096] As described above, the electric storage device according to this modification can achieve the same effects as those of the above-mentioned modification 1. In particular, in this modification, it is only necessary to form recessed portions of simple shapes such as the recessed portions 161 and 162 , so that the cover 160 can be easily manufactured.

[0097] (Other Modifications)

[0098] The above describes the storage element involved in the embodiment of the present invention and its modified examples, but the present invention is not limited to the above embodiment and its modified examples. That is, the embodiment and its modified examples disclosed this time are illustrative and non-restrictive in all aspects, and the scope of the present invention is shown by the scope of the request, including the meaning equivalent to the scope of the request and all changes within the scope.

[0099] In the above-described embodiment and its modified example, the outer surface of the container cover is recessed to form recessed portions such as recessed portions 111 to 118. However, the inner surface of the container cover may be recessed to form the recessed portions.

[0100] In the above embodiment and its variation, the recesses 111 to 118 formed in the lid of the container form thinner portions than adjacent portions. However, the recesses may not form the thinner portions, that is, even if the recesses are formed, the thickness of the lid may not be thinner.

[0101] In the above-mentioned embodiment and its modification, the joint part such as the joint part 130 is a welded part where the container body 120 and the cover are joined by welding. However, the method of joining the container body 120 and the cover is not limited to welding, and for example, the joint part may be a part where the container body 120 and the cover are bonded by an adhesive or the like, or are welded by heat welding or the like. In this case, even when the cover is tilted during joining, the tilt of the cover can be suppressed, and the storage element can be formed with good accuracy.

[0102] In the above-mentioned embodiment and its modified example, the cover body has the gas discharge valve 110a, and the recesses 111 to 118 are arranged at positions that do not overlap with the gas discharge valve 110a when viewed from the extending direction of the recesses. However, the recesses may be arranged at positions that overlap with the gas discharge valve 110a when viewed from the extending direction of the recesses, and the cover body may also be a structure without the gas discharge valve 110a.

[0103] In the above embodiment and its modified example, the recesses 111 to 118 formed in the lid of the container are arranged at a position different from between the gas discharge valve 110a and the joint such as the joint 130. However, the recess may be arranged between the gas discharge valve 110a and the joint.

[0104] Any configuration in which the components included in the above-described embodiment and its modified examples are arbitrarily combined is also included in the scope of the present invention.

[0105] The present invention can be realized not only as an electric storage element but also as a container provided in the electric storage element or a cover of the container.

[0106] Industrial Applicability

[0107] The present invention can be applied to power storage elements such as lithium ion secondary batteries, etc.

[0108] Explanation of symbols

[0109] 10. Storage element;

[0110] 100 containers;

[0111] 110, 140, 150, 160 cover;

[0112] 110a Gas discharge valve;

[0113] 110b, 110c openings;

[0114] 110d, 110e bulge;

[0115] 110f, 140f, 160f peripheral part;

[0116] 111~118, 141, 142, 151, 161, 162 concave parts;

[0117] 111a~118a protrusion;

[0118] 120 container body;

[0119] 130, 131, 132, 133 joints;

[0120] 200 positive terminal;

[0121] 210, 310 shaft;

[0122] 300 negative terminal;

[0123] 400 Electrode body;

[0124] 500 positive electrode collector;

[0125] 510, 610 opening;

[0126] 600 Negative electrode collector.

Claims

1. A storage element comprising: a container having a container body and a cover; and an electrode terminal fixed to the cover, wherein: The outer peripheral portion of the lid is embedded in the interior of the container body. A joining portion between the container body and the lid is formed on a surface of the container on the electrode terminal side. The cover body has a recessed portion that is not disposed between the electrode terminal and the joining portion and is disposed along the joining portion at a position adjacent to the joining portion.

2. The electric storage element according to claim 1, wherein The cover body also has a gas exhaust valve. The recessed portion is disposed at a position that does not overlap with the gas exhaust valve when viewed from the extending direction of the recessed portion.

3. The electric storage element according to claim 2, wherein: The recessed portion is arranged at a position different from a position between the gas exhaust valve and the joint portion.

4. The electric storage element according to any one of claims 1 to 3, wherein The recess is formed on the outer surface of the cover body, A protrusion extending along the recessed portion is formed on the inner surface of the cover.

5. The electric storage element according to any one of claims 1 to 3, wherein The recessed portion is formed by a groove portion extending along the engaging portion.

6. The electric storage element according to any one of claims 1 to 3, wherein The recessed portion is disposed at a position overlapping with the internal space of the container when viewed from the normal direction of the outer surface of the lid.

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