JPWO2017057200A1 - Power storage device and method for manufacturing power storage device - Google Patents

Abstract

An electricity storage device comprising an electrode body (120) formed by laminating a positive electrode plate (122) and a negative electrode plate (123), and a current collector (140) electrically connected to the electrode body (120) In the manufacturing method of (10), the bonding tip (520) having a plurality of protrusions (530) is used to laminate the positive electrode plate (122) and the negative electrode plate (123) in the electrode body (120). A joining step of joining the end portion of the intersecting first direction and the current collector (140). In the joining step, the converging portion that is the end portion of the electrode body (120) by the joining tip (520). By exciting the overlapping portion of (126) and the current collector (140), the first recess (170a) and the second recess (170b) deeper than the first recess (170a) Form.

Description

  The present invention relates to a power storage device including an electrode body and a current collector connected to the electrode body, and a method for manufacturing the same.

  Conventionally, a storage element such as a lithium ion secondary battery has an electrode body in which, for example, a positive electrode plate and a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate are stacked. The electrode body has an end portion (for example, a converging portion) on which metal foil portions not coated with an active material are laminated, and a metal member called a current collector is connected to the converging portion, for example. Is done.

  Further, as a technique for joining the converging portion of the electrode body and the current collector, welding using vibration may be used. For example, there is a technique called ultrasonic bonding in which a vibration by an ultrasonic wave is applied in a state where the focusing portion and the current collector are overlapped to join the focusing portion and the current collector.

  In the secondary battery described in Patent Document 1, the uneven surface is provided on the joint surface of the current collecting member to the current collector foil laminated portion, and the current collector foil of the current collector foil laminated portion is provided in the concave portion of the uneven region. In the state where it has digged in, the current collecting member and the current collector foil laminated portion are joined by ultrasonic joining. Patent Document 1 describes that the above configuration can sufficiently obtain the bonding strength of the bonding portion between the electrode plate of the electrode laminate and the current collecting terminal that extracts current from the electrode plate.

JP 2014-10913 A

  When the converging part of the electrode body and the current collector are joined using a joining technique involving vibration such as ultrasonic joining, the surface of the metal foil that forms the converging part is scraped off, so that a small metal piece May occur. When the metal piece generated in this way moves to the inside of the electrode body, for example, there is a risk of causing problems such as the occurrence of a fine short circuit inside the electrode body.

  In view of the above-described conventional problems, the present invention provides a power storage element in which an electrode body and a current collector are joined using a joining technique involving vibration, and a highly reliable power storage element and a method for manufacturing the same. The purpose is to do.

  In order to achieve the above object, a method for manufacturing a power storage element according to one embodiment of the present invention includes an electrode body formed by stacking electrode plates, and a current collector electrically connected to the electrode body And a current collector using a joining tool having a plurality of protrusions, and an end portion of the electrode body in a first direction intersecting with the stacking direction of the electrode plates, and the current collector In the joining step, the overlapping portion of the end portion of the electrode body and the current collector is vibrated by the joining tool in the joining step so that the first recess And a second recess deeper than the first recess.

  The power storage device according to one embodiment of the present invention is a power storage device including an electrode body formed by laminating electrode plates, and a current collector electrically connected to the electrode body, The electrode body has a joining portion that is a portion where the end portion in the first direction intersecting the laminating direction of the electrode plate and the current collector is joined, and the joining portion is viewed from the laminating direction. A plurality of recesses are formed side by side in the joining region, which is a region in the case where the plurality of recesses include a first recess and a second recess deeper than the first recess. The second recess is formed at a position closer to the center of the electrode body than the first recess in the first direction.

  ADVANTAGE OF THE INVENTION According to this invention, it is an electrical storage element with which the electrode body and the electrical power collector were joined using the joining method with vibration, Comprising: A reliable electrical storage element and its manufacturing method can be provided.

FIG. 1 is a perspective view showing an outline of the internal structure of the energy storage device according to the embodiment. FIG. 2 is a diagram showing a connection mode between the current collector and the negative electrode terminal according to the embodiment. FIG. 3 is a perspective view illustrating a schematic configuration of the electrode body according to the embodiment. FIG. 4 is a diagram illustrating an arrangement example of joint portions according to the embodiment. FIG. 5 is a cross-sectional view showing an outline of a VV cross section in FIG. 4. FIG. 6 is a cross-sectional view showing an outline of a VI-VI cross section in FIG. 4. FIG. 7 is a diagram illustrating an arrangement example of a plurality of concave portions formed in the joint portion according to the embodiment. FIG. 8 is a perspective view showing a schematic configuration of a bonding tip used for bonding the electrode body and the current collector according to the embodiment. FIG. 9A is a first diagram illustrating a part of the manufacturing process of the energy storage device according to the embodiment. FIG. 9B is a second diagram illustrating a part of the manufacturing process of the energy storage device according to the embodiment. FIG. 9C is a third diagram illustrating a part of the manufacturing process of the energy storage device according to the embodiment. FIG. 10 is a diagram illustrating an arrangement example of a plurality of concave portions formed in the joint portion according to the first modification of the embodiment. FIG. 11 is a diagram illustrating an arrangement example of a plurality of concave portions formed in the joint portion according to the second modification of the embodiment. FIG. 12 is a perspective view showing an outline of the internal structure of a power storage element that does not include a clip.

  In order to achieve the above object, a method for manufacturing a power storage element according to one embodiment of the present invention includes an electrode body formed by stacking electrode plates, and a current collector electrically connected to the electrode body And a current collector using a joining tool having a plurality of protrusions, and an end portion of the electrode body in a first direction intersecting with the stacking direction of the electrode plates, and the current collector In the joining step, the overlapping portion of the end portion of the electrode body and the current collector is vibrated by the joining tool in the joining step so that the first recess And a second recess deeper than the first recess.

  According to this method, the end portion of the electrode body and the current collector are joined by vibration with a joining tool having a plurality of protrusions. In this bonding step, a relatively shallow first recess and a relatively deep second recess are formed in the overlapping portion between the end of the electrode body and the current collector. Therefore, even when a minute metal piece (hereinafter also referred to as “foreign matter”) is generated when the first recess is formed, the movement of the foreign matter is regulated by the second recess formed deeper. .

  Thus, the manufacturing method of the electrical storage element which concerns on this aspect is a manufacturing method including the joining process which joins an electrode body and an electrical power collector using the joining method with vibration. According to this manufacturing method, it is possible to manufacture a power storage element having a structure that suppresses the movement of foreign matter generated in the joining process. Therefore, according to the manufacturing method according to this aspect, a highly reliable power storage element can be manufactured.

  Further, in the method for manufacturing a power storage element according to one embodiment of the present invention, the joining step includes an overlapping portion of the end portion of the electrode body and the current collector by one or more of the plurality of protrusions. The electrode body is formed by a first step of forming one or more of the second recesses by vibrating, and one or more other projections of the plurality of projections after the first step is started. It is good also as including the 2nd process of forming one or more above-mentioned 1st crevices by oscillating the overlap part of the above-mentioned end and the above-mentioned current collector.

  According to this manufacturing method, in the joining step, the excitation by the one or more protrusions (first process) is started before the excitation by the one or more other protrusions (second process). Therefore, the foreign matter generated in the second step is regulated by the portion joined by the first step already started or the portion being joined. That is, the movement of the foreign matter generated in the joining process is suppressed.

  Further, in the method for manufacturing a power storage element according to one aspect of the present invention, the plurality of protrusions include a first protrusion and a second protrusion, and the protrusion disposition surface of the second protrusion on which the plurality of protrusions are disposed. The height of the first projection is higher than the height of the first projection from the projection arrangement surface. In the joining step, the joining tool is formed by overlapping the end portion of the electrode body and the current collector. The second step by the first protrusion may be started after the start of the first step by the second protrusion.

  According to this manufacturing method, by moving the joining tool having the first protrusion and the second protrusion having different heights toward the portion where the end of the electrode body and the current collector are overlapped, The first step and the second step can be started in this order. For example, a welding tool that vibrates in the horizontal direction is moved vertically with respect to a portion where the end of the electrode body and the current collector are overlapped, thereby providing a single piece having a plurality of portions with different joining timings. A junction can be formed. As a result, in one joint portion, the portion where the joining is started first functions as an element that hinders the movement of the foreign matter caused by the joining started later, and as a result, the reliability of the storage element is improved. The

  The power storage device according to one embodiment of the present invention is a power storage device including an electrode body formed by laminating electrode plates, and a current collector electrically connected to the electrode body, The electrode body has a joining portion that is a portion where the end portion in the first direction intersecting the laminating direction of the electrode plate and the current collector is joined, and the joining portion is viewed from the laminating direction. A plurality of recesses are formed side by side in the joining region, which is a region in the case where the plurality of recesses include a first recess and a second recess deeper than the first recess. The second recess is formed at a position closer to the center of the electrode body than the first recess in the first direction.

  According to this structure, the 1st recessed part and the 2nd recessed part deeper than a 1st recessed part are formed in the junction part which is the part by which the edge part of the electrode body and the electrical power collector were joined. The joint having this structure is formed, for example, by vibration with a tool having at least two protrusions having different heights. That is, even when a foreign matter is generated when the portion corresponding to the first recess formed relatively shallowly, the movement of the foreign matter is a portion corresponding to the second recess formed relatively deep. Subject to regulations by That is, the possibility that a defect such as a fine short circuit occurs inside the electrode body due to the foreign matter generated in the joining process is reduced. More specifically, since the one or more second recesses are arranged at a position closer to the center of the electrode body than the first recess, the center of the electrode body of the foreign matter generated in the joining of the portions corresponding to the first recesses Directional movement can be suppressed. That is, the possibility that foreign matter generated during the formation of the joint portion reaches the inside of the electrode body is further reduced.

  As described above, the power storage device according to this aspect is a power storage device including the joined electrode body and the current collector, and movement of the foreign matter is suppressed even when foreign matter is generated in the joining process. It is an electrical storage element which has a structure. Therefore, the power storage element according to this embodiment is a highly reliable power storage element.

  In the energy storage device according to one embodiment of the present invention, the plurality of recesses are arranged in a dispersed manner in the joining region, and the second recesses are provided along at least a part of the outer periphery of the joining region. It may be arranged.

  According to this configuration, the portion of the foreign matter generated inside the joining region having a two-dimensional extension is moved relatively deeply outside the joining region and is recessed along the outer periphery of the joining region. (Parts corresponding to the plurality of second recesses) can be efficiently suppressed.

  In the energy storage device according to one embodiment of the present invention, a plurality of the second recesses may be arranged along the outer periphery so as to surround one or more of the first recesses.

  According to this configuration, it is possible to suppress progression of almost all foreign matters generated inside the joining region to the outside of the joining region.

  Further, in the energy storage device according to one aspect of the present invention, the joint includes a portion of the pad disposed along the end of the electrode body and joined to the end, and the plurality of recesses May be formed on the pad.

  According to this configuration, since the end portion of the electrode body and the current collector are bonded using the contact material, for example, high reliability of the bonding can be obtained. Moreover, since the direct contact with the tool used for the said joining and the edge part of an electrode body is prevented, the generation | occurrence | production number of the foreign material in the said joining is suppressed, for example.

  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.

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

  First, with reference to FIG. 1 and FIG. 2, a general description of the electricity storage device 10 according to the embodiment will be given. FIG. 1 is a perspective view showing an outline of the internal structure of a power storage device 10 according to the embodiment. Specifically, FIG. 1 is a diagram in which a part of a battery container 100 described later is omitted in order to illustrate the internal structure of the electricity storage element 10. FIG. 2 is a diagram illustrating a connection mode between the current collector 140 and the negative electrode terminal 300 according to the embodiment.

  The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, for example, a non-aqueous electrolyte secondary battery. Examples of the non-aqueous electrolyte battery include a lithium ion secondary battery in which the positive electrode active material is a lithium transition metal oxide such as lithium cobaltate and the negative electrode active material is a carbon material.

  In addition, the kind of electrical storage element 10 is not limited to a nonaqueous electrolyte secondary battery, Secondary batteries other than a nonaqueous electrolyte secondary battery may be sufficient, and a primary battery may be sufficient. The power storage element 10 may be a capacitor such as a lithium ion capacitor. Further, the power storage element 10 may be a primary battery that can use the stored electricity without being charged by the user.

  As shown in FIG. 1, the energy storage device 10 according to the embodiment includes a battery container 100, a positive electrode terminal 200, and a negative electrode terminal 300. The battery container 100 includes a main body 101 having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid plate 110 that closes an opening of the main body 101. In addition, the battery container 100 has a structure in which after the electrode body 120 and the like are accommodated therein, the lid plate 110 and the main body 101 are welded to seal the inside.

  The positive electrode terminal 200 is attached to the lid plate 110 of the battery container 100 via a gasket 230 for keeping the battery container 100 airtight. Similarly, the negative electrode terminal 300 is also attached to the lid plate 110 of the battery container 100 via the gasket 330.

  Each of the gaskets 230 and 330 is formed of, for example, an insulating resin, and an electrical connection between the metal positive electrode terminal 200 and the negative electrode terminal 300 and the metal battery container 100 (cover plate 110). It also has a role of proper insulation.

  As shown in FIG. 1, an electrode body 120 is accommodated inside the battery container 100, and a positive current collector 130 and a negative current collector 140 are disposed. Yes. In the present embodiment, a liquid such as an electrolytic solution is sealed in the battery container 100 of the power storage element 10, but the liquid is not shown.

  Although not shown in FIG. 1, the current collector 130, the current collector 140, and the lid plate 110 are also interposed between the current collector 130 and the current collector 140 and the lid plate 110. An insulating gasket (lower gasket) is arranged.

  The electrode body 120 includes a positive electrode plate, a negative electrode plate, and a separator, and is a member that can store electricity, and is formed so as to have an oval shape as a whole. Details of the electrode body 120 will be described later with reference to FIG.

  The current collector 130 is a metal member connected to the positive electrode terminal 200 and the electrode body 120. As the material of the current collector 130, for example, aluminum or an aluminum alloy that is the same material as the positive electrode of the electrode body 120 is employed. The current collector 130 has a pair of long connection plate portions 132 connected to the electrode body 120.

  The current collector 140 is a metal member connected to the negative electrode terminal 300 and the electrode body 120. As the material of the current collector 140, for example, copper or a copper alloy that is the same material as the negative electrode of the electrode body 120 is employed. The current collector 140 has a pair of long connection plate portions 142 connected to the electrode body 120.

  In addition, the positive electrode terminal 200 and the current collector 130 are connected by caulking in the present embodiment. Similarly, the negative electrode terminal 300 and the current collector 140 are connected by caulking.

  For example, as shown in FIG. 2, the negative terminal 300 has a rivet portion 305. The rivet portion 305 passes through the gasket 330, the cover plate 110 (see FIG. 1), and a lower gasket (not shown), and is inserted into a through hole 141a provided in the terminal connection portion 141 of the current collector 140. Thus, the tip of the rivet portion 305 is caulked. Thereby, the negative electrode terminal 300 and the current collector 140 are connected.

  Similarly, the positive terminal 200 is connected to the current collector 130 by caulking the rivet portion of the positive terminal 200.

  In power storage element 10 having such a configuration, each of current collector 130 and current collector 140 and electrode body 120 are connected by ultrasonic bonding, which is an example of a bonding technique involving excitation, in the present embodiment. Has been.

  Electrode body 120 has a converging portion in which an uncoated portion, which is a portion where no active material is coated on the electrode plate, is laminated on an end portion in the winding axis direction (X-axis direction in the present embodiment). . In the present embodiment, as shown in FIG. 1, the electrode body 120 includes a converging part 136 in which an uncoated part 122 a of a positive electrode plate is laminated and a converging part 126 in which an uncoated part 123 a of a negative electrode plate is laminated. And have. Each of the converging part 136 and the converging part 126 is an example of an end of the electrode body 120 in the first direction (in the present embodiment, the X-axis direction) intersecting with the electrode plate stacking direction.

  In the present embodiment, the electrode body 120 is a wound electrode body, and on the positive electrode side, two converging portions 136 are arranged in the thickness direction (Y-axis direction in the present embodiment) across the winding shaft. Is formed. Similarly, on the negative electrode side of the electrode body 120, two converging portions 126 are formed in the thickness direction with the winding axis interposed therebetween.

  The connection plate portion 132 included in the current collector 130 is bonded to each of the two focusing portions 136, and the connection plate portion 142 included in the current collector 140 is bonded to each of the two focusing portions 126.

  The description will be made by paying attention to the current collector 140. The current collector 140 is arranged so that the pair of connection plate portions 142 sandwich the end portion on the negative electrode side of the electrode body 120. In this state, each of the pair of connection plate portions 142 and the converging portion 126 are joined by ultrasonic joining.

  At the time of this connection, the plurality of uncoated parts 123a constituting the converging part 126 joined to the connection plate part 142 are gathered near the center in the stacking direction, for example, and connected and pressed while being vibrated. 142.

  As a result of the joining process described above, the electrical storage element 10 has a joined portion that is a portion where the ends (the converging portions 136 and 126) of the electrode body 120 and the current collectors (130 and 140) are vibrated and joined. 160 is formed.

  In the present embodiment, the joint 160 is formed with a plurality of recesses 170, and at least one of the plurality of recesses 170 is formed deeper than one or more other recesses 170. The joint 160 included in the power storage element 10 according to the present embodiment will be described later with reference to FIGS.

  Here, in the present embodiment, the end portions (the converging portions 136 and 126) of the electrode body 120 and the current collectors 130 and 140 are joined using a clip that is an example of a patch. Specifically, one clip 150 is disposed on each of the pair of connection plate portions 132 of the current collector 130 and the pair of connection plate portions 142 of the current collector 140.

  To explain with a focus on one connection plate portion 142, one clip 150 is arranged so as to sandwich the converging portion 126 and the connection plate portion 142 of the electrode body 120. That is, the connection plate portion 142 and the converging portion 126 are joined to each other by applying ultrasonic vibration while being pressed while the connection plate portion 142 and the converging portion 126 are sandwiched between the clips 150.

  The clip 150 is a metal member used as an auxiliary so that the converging portion 136 (126) formed by laminating metal foils is not damaged by vibration caused by ultrasonic waves. The clip 150 also has a role as a member that collects these elements to be joined when the converging part 136 (126) and the connecting plate part 132 (142) are joined.

  In addition, as a material of the clip 150 attached to the current collector 130 on the positive electrode side, for example, aluminum or aluminum alloy which is the same material as the positive electrode of the electrode body 120 is employed. In addition, as a material of the clip 150 attached to the negative electrode side current collector 140, for example, copper or a copper alloy which is the same material as the negative electrode of the electrode body 120 is employed.

  Further, the clip 150 is a member that is used supplementarily as described above, and is not essential for joining the electrode body 120 and the current collectors 130 and 140. For example, the converging part 126 and the connecting plate part 142 are vibrated while directly applying a joining chip to be described later to one of the converging part 126 of the electrode body 120 and the connecting plate part 142 of the current collector 140. It may be joined.

  Next, a configuration outline of the electrode assembly 120 according to the present embodiment will be described with reference to FIG. FIG. 3 is a perspective view showing a schematic configuration of the electrode body 120 according to the embodiment.

  The electrode body 120 is an example of an electrode body formed by winding an electrode plate. In the present embodiment, as shown in FIG. 3, the electrode body 120 is formed by alternately stacking and winding the positive electrode plate 122 and the negative electrode plate 123 and the two separators 124 and 125. Yes.

  That is, the electrode body 120 is formed by laminating the positive electrode plate 122, the separator 124, the negative electrode plate 123, and the separator 125 in this order and winding the cross section into an oval shape. Yes.

  That is, the electrode body 120 has a flat shape having a curved portion and a straight portion as shown in FIG. Specifically, the electrode body 120 includes a linear portion (pole) between the upper and lower curved portions in FIG. 3 (the portions where the electrode plates are turned on the positive and negative sides in the Z-axis direction) and the upper and lower curved portions. The plate is parallel to the Z-axis direction).

The positive electrode plate 122 is obtained by forming a mixture layer containing a positive electrode active material on the surface of a long metal foil made of aluminum. As the positive electrode active material contained in the mixture layer of the positive electrode plate 122, for example, LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more selected from Fe, Ni, Mn, Co, etc.) Polyanion compounds such as transition metal elements), spinel compounds such as lithium titanate and lithium manganate, LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), etc. Lithium transition metal oxide or the like can be used.

The negative electrode plate 123 is obtained by forming a mixture layer including a negative electrode active material layer on the surface of an elongated metal foil made of copper. As the negative electrode active material contained in the mixture layer of the negative electrode plate 123, for example, a known material can be used as appropriate as long as it is a negative electrode active material capable of occluding and releasing lithium ions. For example, lithium is occluded in addition to lithium metal and lithium alloys (lithium-containing alloys such as lithium-aluminum, lithium-silicon, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys).・ Releasable alloys, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₆ O ₁₂ etc.) And polyphosphoric acid compounds.

  More specifically, in the electrode body 120 configured as described above, the positive electrode plate 122 and the negative electrode plate 123 are wound while being shifted from each other in the winding axis direction via the separators 124 and 125. And the positive electrode plate 122 and the negative electrode plate 123 have the uncoated part which is a part in which the active material is not coated in the edge part of each shifted direction. The uncoated part is also called, for example, “mixture layer non-formed part”.

  That is, as described above, the positive electrode plate 122 has the converging part 136 in which the uncoated part 122a not coated with the positive electrode active material is laminated at one end in the winding axis direction. Further, as described above, the negative electrode plate 123 has the converging portion 126 in which the uncoated portion 123a not coated with the negative electrode active material is laminated on the other end in the winding axis direction.

  The power storage element 10 having the above-described configuration has a feature in the joint portion 160 that is a joint portion between the electrode body 120 and the current collectors 130 and 140. Further, in the present embodiment, the shape and attachment of negative side members (negative electrode terminal 300, current collector 140, clip 150, etc.) and positive side members (positive electrode terminal 200, current collector 130, clip 150, etc.) The structure and the like are substantially the same. Therefore, paying attention to the joint 160, which is a portion where the electrode body 120 and the current collector 140 are joined, the characteristics of the structure and the like will be described with reference to FIGS. 4 to 9C.

  FIG. 4 is a diagram illustrating an arrangement example of the joint 160 according to the embodiment. In FIG. 4, the clip 150 and the like are not shown. FIG. 5 is a cross-sectional view showing an outline of a VV cross section in FIG. 4. FIG. 6 is a cross-sectional view showing an outline of a VI-VI cross section in FIG. 4. FIG. 7 is a diagram illustrating an arrangement example of the plurality of concave portions 170 formed in the joint portion 160 according to the embodiment. In FIG. 7, a circular region with a thin dot represents the first concave portion 170a, and a circular region with a dark dot represents the second concave portion 170b. This also applies to FIGS. 10 and 11 described later.

  The electricity storage device 10 according to the present exemplary embodiment includes a joint 160 that is a portion where the converging unit 126 that is an end of the electrode body 120 and the current collector 140 are joined by vibration. In the present embodiment, as shown in FIG. 4, two portions in the longitudinal direction of the connection plate portion 142 that is long in the Z-axis direction are joined to the converging portion 126 of the electrode body 120. In other words, in the present embodiment, two connecting portions 160 are formed per one connecting plate portion 142. Note that the number of the joint portions 160 is not particularly limited, and one or three or more joint portions 160 may be formed for one connection plate portion 142.

  As shown in FIGS. 5 to 7, a plurality of recesses 170 are formed in the bonding region 165, which is a region when the bonding portion 160 is viewed from the electrode plate stacking direction (Y-axis direction in the present embodiment). Are formed side by side. More specifically, in the present embodiment, the converging portion 126 is vibrated by a joining tip (described later with reference to FIG. 8) via the clip 150. Therefore, a plurality of concave portions 170 are formed side by side in the bonding region 165 that is a region when the bonding portion 160 is viewed from the converging portion 126 side (Y-axis direction plus side). In addition, the joining area | region 165 in which these some recessed part 170 was formed may be called a "welding trace", for example.

  Moreover, the some recessed part 170 formed in the junction part 160 contains the 1st recessed part 170a and the 2nd recessed part 170b deeper than the 1st recessed part 170a. That is, when the depth of the first recess 170a is D1, and the depth of the second recess 170b is D2, D2> D1. Moreover, D2: D1 is about 5: 4, for example.

  The joining portion 160 having this structure is formed by vibration by a joining tip having at least two protrusions having different heights. That is, for example, the joining of the part corresponding to the second recessed part 170b is started before the joining of the part corresponding to the first recessed part 170a. Therefore, when a minute metal piece (hereinafter also referred to as “foreign matter”) is generated at the time of joining the portion corresponding to the first concave portion 170a, the movement of the foreign matter is restricted by the portion corresponding to the second concave portion 170b. receive. Further, for example, even when the vibration is started in a state where the joining tip is pressed against the overlapping portion of the converging portion 126 and the current collector 140, the second portion formed relatively deeply. The concave portion 170b and the portion immediately below the concave portion 170b exist as a wall that suppresses the movement of the foreign matter generated when the first concave portion 170a is formed.

  Thereby, generation | occurrence | production of the fine short circuit resulting from the said foreign material is suppressed, for example. More specifically, the metal may be ionized when a minute metal piece that is a foreign substance comes into contact with the positive electrode plate 122 of the electrode body 120. In this case, when the ionized metal reaches the nearby negative electrode plate 123, the metal precipitates to form dendrite, and this dendrite penetrates the separator 125 to form a fine particle between the positive electrode plate 122 and the negative electrode plate 123. May cause a short circuit. However, in the present embodiment, as described above, the movement of the foreign matter generated in the process of forming the joint 160 is suppressed by a part of the joint 160. Therefore, the possibility of occurrence of problems such as the fine short circuit is reduced.

  Thus, power storage element 10 according to the present embodiment is power storage element 10 having a structure in which the movement of the foreign matter is suppressed even when the foreign matter is generated in the bonding step. Therefore, the power storage element according to this aspect is a highly reliable power storage element 10.

  Specifically, in the present embodiment, in the rectangular joint region 165, three concave portions 170 arranged in the X-axis direction are arranged in the Y-axis direction. That is, the joint 160 has 15 recesses 170 arranged in a dispersed manner in the joint region 165. In addition, a plurality (12 in this embodiment) of second recesses 170b are arranged along the outer periphery of the joining region 165 so as to surround one or more (three in this embodiment) first recesses 170a. ing.

  That is, the second recessed portion 170b is located on the outermost side in the joining region 165, and the first recessed portion 170a is located on the inside of the second recessed portion 170b in the joining region 165.

  That is, when the joint 160 is viewed from the stacking direction (Y-axis direction), the second recess 170b deeper than the first recess 170a formed inside is formed at the end of the joint region 165. Progress of foreign matter generated inside the region 165 to the outside of the joining region 165 is suppressed.

  More specifically, a plurality of second recesses 170b are arranged along the outer periphery of the joining region 165 so as to surround one or more (three in the present embodiment) first recesses 170a. According to this configuration, it is possible to suppress progression of almost all foreign matters generated inside the joining region 165 to the outside of the joining region 165.

  From the viewpoint of the positional relationship between the first recess 170a and the second recess 170b and the electrode body 120, as shown in FIG. 7, the one or more second recesses 170b are arranged in the first direction (X-axis direction). In FIG. 2, the first recessed portion 170a is formed closer to the center of the electrode body 120.

  According to this configuration, it is possible to suppress the movement of the foreign matter generated in the joining of the portion corresponding to the first recess 170a toward the center of the electrode body 120. That is, it is possible to more efficiently prevent the foreign matter generated during the formation of the joint 160 from moving into the electrode body 120. Therefore, the possibility of occurrence of defects such as a fine short circuit due to the foreign matter reaching the inside of the electrode body 120 is further reduced.

  The joining part 160 configured in this way is formed by executing the manufacturing process shown in FIGS. 9A to 9C using, for example, the joining chip 520 shown in FIG.

  FIG. 8 is a perspective view showing a schematic configuration of a bonding tip 520 used for bonding the electrode body 120 and the current collector 140 according to the embodiment. FIG. 9A is a first diagram illustrating a part of the manufacturing process of the electricity storage device 10 according to the embodiment, FIG. 9B is a second diagram illustrating a part of the manufacturing process, and FIG. It is a 3rd figure which shows a part of the said manufacturing process. 9A to 9C, the joining chip 520 has the IX-IX cross section shown in FIG. 8, and the converging part 126, the connecting plate part 142, and the clip 150 correspond to the IX-IX cross section. A cross section of the position is shown. In FIG. 9B and FIG. 9C, the dot area shown below the protrusion 530 represents a main area in which interface bonding by the vibration by the protrusion 530 is in progress or has been completed. .

  The joining tip 520 used for joining the electrode body 120 and the current collector 140 is an example of a joining tool. As shown in FIGS. 8 and 9A, the first protrusion 530a and the second protrusion 530a having different heights are used. A projection arrangement surface 521 on which a plurality of projections 530 including the projection 530b are arranged is provided.

  In the present embodiment, 15 protrusions 530 are arranged in a rectangular arrangement region 525 on the protrusion arrangement surface 521. In addition, the twelve second protrusions 530b arranged along the outer periphery of the arrangement area 525 so as to surround the first protrusions 530a rather than the three first protrusions 530a arranged inside the arrangement area 525. high. That is, when the height of the first protrusion 530a is H1, and the height of the second protrusion 530b is H2, H2> H1. Moreover, H2: H1 is about 5: 4, for example. The reference for the height of the protrusion 530 is the protrusion arrangement surface 521.

  The manufacturing method of the electrical storage element 10 performed using the joining chip 520 configured as described above will be described as follows. In other words, the method for manufacturing power storage element 10 according to the present embodiment includes a bonding step of bonding focusing portion 126 of electrode body 120 and current collector 140 using bonding chip 520 having a plurality of protrusions 530. . In the bonding step, the overlapping portion of the end portion (the converging portion 126) of the electrode body 120 and the current collector 140 is vibrated by the bonding tip 520, so that the first recess 170a and the first A second recess 170b deeper than the recess 170a is formed.

  That is, in the joining process, a relatively shallow first recess 170a and a relatively deep second recess 170b are formed in the overlapping portion of the converging portion 126 and the current collector 140. Therefore, even when a foreign substance is generated when the first concave portion 170a is formed, the movement of the foreign substance is restricted by the second concave portion formed deeper and a portion immediately below the second concave portion. Therefore, for example, the occurrence of problems such as a fine short circuit caused by the movement of foreign matter into the electrode body 120 is suppressed. That is, according to the method for manufacturing power storage device 10 according to the present embodiment, power storage device 10 having a structure in which the movement of the foreign material can be suppressed even when a foreign material is generated in the joining process. it can. Therefore, according to the method for manufacturing power storage element 10 according to the present embodiment, highly reliable power storage element 10 can be manufactured.

  In more detail, the bonding step according to the present embodiment is performed by exciting the overlapping portion of the converging portion 126 and the current collector 140 by one or more of the plurality of protrusions 530. The first step of forming one or more second concave portions 170b, and after the first step is started, the converging portion 126 and the current collector 140 are formed by one or more other projections 530 among the plurality of projections 530. And a second step of forming one or more first recesses 170a by vibrating the overlapping portion. Accordingly, the foreign matter generated in the second step is regulated by the portion joined by the first step already started or the portion being joined. That is, the movement of the foreign matter generated in the joining process is suppressed.

  Specifically, as shown in FIG. 9A, the bonding tip 520 is attached to the tip of a horn 510 provided in the ultrasonic bonding machine. Further, the overlapping portion of the converging portion 126 of the electrode body 120 and the connecting plate portion 142 of the current collector 140 is disposed on an anvil (not shown). In the present embodiment, as shown in FIG. 9A, the overlapped portion is arranged in a state of being covered by the clip 150.

  Thereafter, the bonding tip 520 approaches the bonding target including the overlapping portion. At this time, as shown in FIG. 9B, among the first protrusion 530a and the second protrusion 530b having different heights, the second protrusion 530b having a higher height is to be joined (directly) before the first protrusion 530a. To reach the clip 150) and vibrate the objects to be joined.

  That is, the joining of the part corresponding to the second protrusion 530b is started before the joining of the part corresponding to the first protrusion 530a. Thereafter, the first protrusion 530a reaches the object to be joined, and the joining of the portion corresponding to the first protrusion 530a to be joined is started, and the joining process for the object to be joined is completed as shown in FIG. 9C. That is, the joint 160, which is a portion where the converging portion 126 of the electrode body 120 and the current collector 140 are joined by vibration, is formed.

  Thus, in the present embodiment, the plurality of protrusions 530 included in the bonding chip 520 include the first protrusion 530a and the second protrusion 530b, and the height of the second protrusion 530b from the protrusion arrangement surface 521 is The height of the first protrusion 530a from the protrusion arrangement surface 521 is higher. Further, in the joining step, the joining tip 520 is moved toward the overlapping portion of the converging portion 126 of the electrode body 120 and the current collector 140, so that the first step by the second protrusion 530b is started. The second step by the one protrusion 530a is started.

  That is, by moving the joining tip 520 that vibrates in the horizontal direction perpendicularly to the overlapping portion of the converging portion 126 and the current collector 140 of the electrode body 120, a plurality of portions having different joining timings can be obtained. One joint 160 having the same can be formed. Thereby, in one joint part 160, the part where joining was started first functions as an element which inhibits the movement of the foreign material produced by joining started later.

  That is, for example, one bonding portion 160 having a structure that suppresses the movement of the foreign matter can be formed by the vertical movement of one bonding tip 520 that vibrates by ultrasonic energy. Thereby, the highly reliable electrical storage element 10 can be manufactured efficiently.

  Here, a specific description will be given of the fact that the part where the joining is started first inhibits the movement of the foreign matter caused by the joining started later in one joining part 160.

  For example, a case is assumed in which minute metal pieces that are foreign matters are generated by rubbing adjacent metal foils of the converging portion 126 included in the region immediately below the first protrusion 530a. In this case, when the foreign matter is generated, the adjacent metal foils of the converging portion 126 immediately below the second protrusion 530b are already joined or being joined by the vibration by the second protrusion 530b. Therefore, the foreign matter generated in the region immediately below the first protrusion 530a is unlikely to move beyond the region immediately below the second protrusion 530b.

  Therefore, even if foreign matter is generated in a portion corresponding to some of the protrusions in the joining step of joining the converging portion 126 and the current collector 140 by exciting with a plurality of protrusions 530, the foreign matter This movement is constrained by other parts that have been joined or are in progress.

  Note that the vibration may be started in a state where the bonding tip 520 is pressed against the overlapping portion of the converging unit 126 and the current collector 140. That is, the joining of the portion corresponding to the first recess 170a by the first protrusion 530a and the joining of the portion corresponding to the second recess 170b by the second protrusion 530b may be started simultaneously or substantially simultaneously. Even in this case, it is difficult for the foreign matter generated during the formation of the relatively shallow first recess 170a to move beyond the second recess 170b that is formed relatively deep and directly below the second recess 170b. That is, the second recess 170b formed relatively deeply and the portion immediately below the second recess 170b exist as walls that suppress the movement of foreign matter generated during the formation of the first recess 170a. Therefore, the movement of the foreign matter generated in the joining process is suppressed.

  In addition, as illustrated in FIGS. 5 to 7, the power storage device 10 manufactured by the above manufacturing method corresponds to the first recess 170 a corresponding to the first protrusion 530 a and the second protrusion 530 b in the joint 160. A plurality of recesses 170 including the second recesses 170b are formed.

  In other words, as described above, the power storage element 10 having the joint 160 in which the plurality of recesses 170 are formed suppresses the movement of the foreign matter generated in the joining process to the outside of the joint 160 in the manufacturing process. ing. Further, even when the power storage element 10 is used after manufacturing, the movement of foreign matter remaining inside the joint 160 to the outside of the joint 160 is suppressed.

  In other words, the joint 160 included in the power storage element 10 has a structure that allows foreign matters that may cause defects to remain inside the joint 160 during and after the manufacture of the power storage element 10. Thereby, the highly reliable power storage element 10 is realized.

  Further, in the present embodiment, the joint 160 includes a portion of the pad (clip 150) disposed along the converging part 126 of the electrode body 120 and joined to the converging part 126, and the plurality of recesses 170 includes The clip 150 is formed.

  In this way, the converging part that is formed by laminating the metal foil by exciting the converging part 126 via the clip 150 and that is easily damaged such as peeling or cracking. 126 can be protected. Specifically, since direct contact between the bonding tip 520 and the converging portion 126 of the electrode body is prevented, for example, the number of foreign matters generated in the bonding process for forming the bonding portion 160 is suppressed. In addition, it is possible to obtain an effect of improving the bonding strength at the bonding portion 160.

  Note that the power storage element 10 may include a joint 160 having a shape or structure different from that of the joint 160 illustrated in FIGS. Therefore, in the following, various modified examples related to the joint portion 160 according to the embodiment will be described focusing on differences from the above embodiment.

(Modification 1)
FIG. 10 is a diagram illustrating an arrangement example of the plurality of concave portions 170 formed in the joint portion 160a according to the first modification of the embodiment.

  In the joint 160a shown in FIG. 10, a plurality of recesses 170 are formed in a substantially rectangular joint region 165, and the plurality of recesses 170 are a first recess 170a and a second deeper than the first recess 170a. A recess 170b is provided. About these points, it is common with the junction part 160 which concerns on the said embodiment.

  However, in the joint portion 160a according to this modification, a plurality of the second concave portions 170b are arranged along only a part of the outer periphery of the joint region 165, and in this respect, the joint according to the above embodiment is provided. Different from the unit 160.

  Specifically, in the bonding region 165 in the bonding portion 160a, five second concave portions 170b are formed along a side on the minus side in the X-axis direction (see, for example, FIG. 10) that is a side on the center side of the electrode body 120. The remaining ten concave portions 170 are all the first concave portions 170a.

  In this case, at the time when the portions corresponding to the first concave portions 170a are joined, the joining of the portions corresponding to the vertical concave portions 170b corresponding to one vertical line closest to the center of the electrode body 120 has already been started.

  Therefore, when a foreign material is generated in the joining of the portions corresponding to the plurality of first concave portions 170a of the converging portion 126, the movement of the foreign material toward the center of the electrode body 120 is caused to the second concave portion 170b of the converging portion 126. Suppressed by the corresponding part.

  That is, the power storage element 10 can suppress the movement of the foreign matter generated in the bonding process even when the power storage element 10 includes the bonding portion 160a according to the present modification, thereby obtaining high reliability.

  A plurality of the second recesses 170b may be arranged along only the other side in the bonding region 165. For example, when the power storage element 10 is in the posture shown in FIG. 10, that is, when the longitudinal direction of the connection plate 142 (see FIG. 1) of the current collector 140 coincides with the Z-axis direction. Suppose. In this case, only the three second recesses 170b may be arranged along the lower side of the bonding region 165 in FIG. Thereby, it is suppressed that the foreign material which generate | occur | produced in the joining process flows out of the junction part 160a by gravity.

  That is, when the plurality of recesses 170 are dispersedly arranged in the bonding region 165, the second recesses 170b may be arranged along at least a part of the outer periphery of the bonding region 165. As a result, the movement of the foreign matter generated in the bonding process to the outside of the bonding portion 160a is disposed along the outer periphery of the bonding region 165 and is relatively deeply depressed (corresponding to the plurality of second concave portions 170b). Can be efficiently suppressed.

(Modification 2)
FIG. 11 is a diagram illustrating an arrangement example of the plurality of concave portions 170 formed in the joint portion 160b according to the second modification of the embodiment.

  In the joint 160b shown in FIG. 11, the plurality of recesses 170 are arranged in a distributed manner, and the plurality of second recesses 170b are arranged along the outer periphery of the joint region 165a so as to surround one or more first recesses 170a. Has been. About these points, it is common with the junction part 160 which concerns on the said embodiment.

  However, in the joint 160b according to this modification, the joint region 165a is elliptical, and the plurality of second recesses 170b are arranged along the outer periphery of the ellipse, so that a plurality (10 in the present embodiment). ) First recesses 170a. This is different from the joint 160 according to the above-described embodiment.

  That is, the plurality of recesses 170 formed in the joint 160b do not have to be arranged in a matrix as shown in FIG. 7 or FIG. 10, and each of the plurality of recesses 170 is within a predetermined plane area. You may arrange | position in arbitrary positions.

  Even in this case, the bonding portion 160b is formed with the plurality of second recesses 170b so as to surround the plurality of first recesses 170a inside the bonding region 165a, whereby the bonding according to the first embodiment is performed. The same effect as the part 160 is produced. In other words, almost all foreign matters generated inside the joining region 165a can be prevented from proceeding to the outside of the joining region 165a (that is, movement of foreign matter from the inside of the joining portion 160b).

  The plurality of second recesses 170b need not be arranged along the entire outer periphery of the bonding region 165a, and the plurality of second recesses 170b are arranged along only a part of the outer periphery of the bonding region 165a. May be.

(Other embodiments)
As described above, the power storage device according to the present invention has been described based on the embodiment and the modifications thereof. However, the present invention is not limited to the above-described embodiment and its modifications. As long as it does not deviate from the gist of the present invention, various modifications conceived by those skilled in the art may be applied to the above-described embodiment or its modifications, or a form constructed by combining a plurality of the constituent elements described above. Included within the scope of the invention.

  For example, the joint 160 may have a larger number of first recesses 170a than the second recesses 170b. Thereby, the movement of the foreign material generated in the formation of each of the relatively large number of first recesses 170a is suppressed by the one or more second recesses 170b and the portion immediately below the second recesses 170b. This is the same when the ratio of the one or more first recesses 170a is larger than the ratio of the one or more second recesses 170b in the plan view of the bonding region 165 (see FIG. 7).

  Further, for example, the plurality of concave portions 170 included in the joint portion 160 may not be formed in the clip 150. FIG. 12 is a perspective view showing an outline of the internal structure of the energy storage device 10 a that does not include the clip 150. The power storage element 10a shown in FIG. 12 is common to the power storage element 10 according to the above embodiment except that the clip 150 is not provided, and a detailed description thereof is omitted.

  When a contact material such as the clip 150 is not used for joining the converging part 126 of the electrode body 120 and the connecting plate part 142 of the current collector 140, the joining chip 520 includes either the converging part 126 or the connecting plate part 142. (In the electric storage element 10a shown in FIG. 12, the bonding tip 520 is pressed against the converging portion 126). In this case, a joining region 165 in which a plurality of recesses 170 are arranged is formed on the one side, and the plurality of recesses 170 includes a plurality of first recesses 170a and a plurality of second recesses 170b (for example, FIG. 5). To FIG. 7). Even in this case, for example, the movement of the foreign matter generated in the portion corresponding to the first recess 170a of the converging portion 126 is suppressed by the portion corresponding to the second recess 170b.

  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 may include a stacked electrode body in which flat plate plates are stacked, for example. Moreover, the electrical storage element 10 may be provided with the electrode body which has a structure which laminated | stacked the elongate strip | belt-shaped electrode plate on the bellows shape by repeating a mountain fold and a valley fold, for example. In any case, a converging portion formed by laminating an active material uncoated portion of the positive electrode plate or the negative electrode plate is formed at the end portion of the electrode body. As the joining portion between the converging portion and the current collector, for example, the joining portion 160 according to the above-described embodiment is formed, so that the effect of suppressing movement of foreign matter generated in the joining step can be obtained.

  Further, it is not necessary that three or more concave portions 170 are formed in the joint portion 160, and only one first concave portion 170 a and one second concave portion 170 b may be formed in the joint portion 160. In this case, for example, the first recess 170a and the second recess 170b are arranged in the X-axis direction, and the second recess 170b is closer to the center of the electrode body 120 than the first recess 170a (for example, in FIG. 7). It is preferable to arrange on the minus side in the X-axis direction. That is, it is preferable to perform the joining process so that the joining of the portion near the center of the electrode body 120 in the joining portion 160 is started before joining the distant portion. Thereby, the movement toward the center of the electrode body 120 of the foreign material produced at the time of joining of the part corresponding to the 1st recessed part 170a can be suppressed.

  The plurality of protrusions 530 included in the bonding tip 520 used for forming the bonding portion 160 may have different heights in three or more stages. For example, the bonding tip 520 may have a third protrusion that is taller than the second protrusion 530 b as at least one protrusion 530 of the plurality of protrusions 530. In this case, the bonding tip 520 that vibrates in the horizontal direction is moved vertically with respect to the overlapping portion of the converging portion 126 and the current collector 140 of the electrode body 120, so that three portions having different bonding timings can be obtained. A single joint 160 having the following can be formed. That is, the joining part 160 may have a third recessed part deeper than the second recessed part 170 b as at least one recessed part 170 among the plurality of recessed parts 170. Even in this case, in the joining process for forming the joining portion 160, the part where the joining is started first in time series (preceding joining part) is the part where the joining is started later (following joining part). It can exist as a wall against the generated foreign matter. That is, there is an effect of suppressing movement of the foreign matter generated in the joining process.

  Further, the joining chip 520 may have a plurality of protrusions 530 having a uniform height. In this case, for example, the bonding tip 520 is placed in a position where the protrusion arrangement surface 521 of the bonding tip 520 is inclined with respect to the overlapping portion of the converging portion 126 and the current collector 140 of the electrode body 120. Press against the part. Thereby, one or more protrusions of the plurality of protrusions 530 can be pressed against the overlapped portion before the other one or more protrusions. That is, in the joint portion 160, a plurality of portions having different joining timings can be formed. Even in this case, the effect of suppressing the movement of the foreign matter generated at the subsequent bonding portion by the preceding bonding portion can be obtained. Even when the joining step is performed in this manner, at least two concave portions 170 having different depths are formed in the joining portion 160.

  When the bonding chip 520 has a plurality of protrusions 530 having a uniform height, for example, one or more second recesses 170b are first formed using the bonding chip 520, and then the bonding chip 520 is formed. May be moved (or the overlapping portion of the converging portion 126 and the current collector 140 may be moved) to form one or more first recesses 170a. That is, two types of concave portions 170 (first concave portion 170a and second concave portion 170b) having different depths may be formed by performing the bonding operation twice using one bonding chip 520. In addition, when forming the 2nd recessed part 170b and the 1st recessed part 170a by 2 joining operations in this way, you may form each of the 2nd recessed part 170b and the 1st recessed part 170a with another chip | tip for joining. That is, as the joining tool (joining tip 520) used in the method for manufacturing the energy storage device 10 according to the present embodiment, the first joining tool for forming the first recess 170a and the second recess 170b are used. Two types of joining tools, the second joining tool for forming, may be employed.

  In addition, the shape of the bonding region does not need to be rectangular (for example, the bonding region 165 (see FIG. 7)) or elliptical (for example, the bonding region 165a (see FIG. 11)), and the plurality of concave portions 170 are arranged side by side. As long as it is a region to be processed, it can take any shape as appropriate.

  Further, although the current collector 140 has a pair of connection plate portions 142, the current collector 140 only needs to have at least one connection plate portion 142. In this case, two converging portions 126 that exist in the thickness direction across the winding axis on the negative electrode side of the electrode body 120 may be collectively bonded to one connection plate portion. That is, the “two converging units 126” may be physically handled as one converging unit 126.

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

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Battery container 101 Main body 110 Cover plate 120 Electrode body 122 Positive electrode plate 122a, 123a Uncoated part 123 Negative electrode plate 124, 125 Separator 126, 136 Converging part 130, 140 Current collector 132 Connection board part 141 Terminal connection part 141a Through-hole 142 Connection plate part 150 Clip 160, 160a, 160b Joint part 165, 165a Joint area 170 Concave part 170a First concave part 170b Second concave part 200 Positive electrode terminal 230, 330 Gasket 300 Negative electrode terminal 305 Rivet part 510 Horn 520 Joint chip 521 Protrusion arrangement surface 525 Arrangement area 530 Protrusion 530a First protrusion 530b Second protrusion

Claims (7)

An electrode body formed by laminating electrode plates, and a method of manufacturing an electricity storage device comprising a current collector electrically connected to the electrode body,
Using a joining tool having a plurality of protrusions, including a joining step of joining the current collector and an end portion of the electrode body in a first direction intersecting a lamination direction of the electrode plates;
In the joining step, the overlapping portion of the end portion of the electrode body and the current collector is vibrated by the joining tool so that the portion is deeper than the first recess and the first recess. A method for manufacturing a power storage element that forms a second recess. The joining step includes
A first step of forming one or more second recesses by exciting the overlapping portion of the end of the electrode body and the current collector with one or more of the plurality of protrusions; ,
After the first step is started, the overlapping portion of the end portion of the electrode body and the current collector is vibrated by one or more other protrusions of the plurality of protrusions. The manufacturing method of the electrical storage element of Claim 1 including the 2nd process of forming the above said 1st recessed part. The plurality of protrusions include a first protrusion and a second protrusion,
The height of the second protrusion from the protrusion arrangement surface on which the plurality of protrusions are arranged is higher than the height of the first protrusion from the protrusion arrangement surface.
In the joining step, after the start of the first step by the second protrusion, the joining tool is moved toward the overlapping portion of the end of the electrode body and the current collector. The method for manufacturing a power storage element according to claim 2, wherein the second step by the first protrusion is started. An electrical storage element comprising an electrode body formed by laminating electrode plates, and a current collector electrically connected to the electrode body,
The electrode body has a joining portion which is a portion where the end portion in the first direction intersecting the stacking direction of the electrode plates and the current collector are joined,
A plurality of recesses are formed side by side in the bonding region, which is a region when viewed from the stacking direction of the bonding portion,
The plurality of recesses include a first recess and a second recess deeper than the first recess,
The one or more second recesses are formed in a position closer to the center of the electrode body than the first recess in the first direction. The plurality of recesses are arranged dispersed in the joining region,
The power storage element according to claim 4, wherein a plurality of the second recesses are arranged along at least a part of the outer periphery of the joining region. The power storage device according to claim 5, wherein a plurality of the second recesses are arranged along the outer periphery so as to surround one or more of the first recesses. The joint includes a portion of the pad disposed along the end of the electrode body and joined to the end.
The power storage device according to any one of claims 4 to 6, wherein the plurality of recesses are formed in the contact member.

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