JP2016195015A - Power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element that can reduce the electrical resistance between an electrode body and a current collector.SOLUTION: A power storage element 10 includes an electrode body 400, and a positive electrode current collector 120 and a negative electrode current collector 130 which are connected to the electrode body 400. The electrode body 400 has tab portions 411 and 421 which protrude outward and are connected to the positive electrode current collector 120 and the negative electrode current collector 130. The electric storage device 10 further includes electrically conductive materials 510 and 520 which are arranged in contact with the tab portions 411 and 421.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power storage device including an electrode body and a current collector connected to the electrode body.

  The shift from gasoline cars to electric cars has become important as a global environmental problem. For this reason, development of an electric vehicle using a power storage element such as a lithium ion secondary battery as a power source is being promoted.

  2. Description of the Related Art Conventionally, in an electrode body in which a positive electrode and a negative electrode are laminated, a configuration of a power storage element in which an uncoated portion that is not coated with an active material is drawn from the positive electrode and the negative electrode of each layer to form a tab portion is widely known (for example , See Patent Document 1).

JP 2013-161756 A

  In general, in an electric storage element, for example, an increase in output can be achieved by reducing an internal resistance such as an electric resistance between an electrode body and a current collector.

  However, in the configuration in which the tab portion is provided, for example, the tab portion is limited from the viewpoint of ensuring insulation between the tab portion on the positive electrode side and the tab portion on the negative electrode side, and restricting the arrangement of the storage element in the container. In some cases, the film can be formed only with a width less than that. In this case, it is difficult to reduce the electrical resistance between the electrode body and the current collector.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a storage element that can reduce the electrical resistance between an electrode body and a current collector.

  In order to achieve the above object, a power storage element according to one embodiment of the present invention is a power storage element including an electrode body and a current collector connected to the electrode body, and the electrode body is disposed outwardly. It has a tab portion that protrudes and is connected to the current collector, and the power storage device further includes a conductive material disposed in contact with the tab portion.

  According to this, since the conductive material is disposed in contact with the tab portion, the cross-sectional area of the conductive body between the electrode body and the current collector can be increased. Therefore, the electrical resistance between the electrode body and the current collector can be reduced.

  The power storage element further includes a container that houses the electrode body and includes a safety valve, and the conductive material is disposed at a position different from the position between the safety valve and the electrode body. May be.

  According to this, since the conductive material is disposed in a portion different from between the safety valve and the electrode body, it is difficult to prevent the pressure from being released when the pressure in the container rises. That is, the gas in the container can be quickly discharged out of the container.

  The conductive material may be disposed so as to surround the outer periphery of the tab portion.

  According to this, since the outer periphery of the tab portion is surrounded by the conductive material, the cross-sectional area of the conductor between the electrode body and the current collector can be further increased. Therefore, the electrical resistance between the electrode body and the current collector can be further reduced.

  Further, the conductive material may be a conductive tape attached to the tab portion.

  According to this, the cross-sectional area of the conductor between the electrode body and the current collector can be easily increased by attaching the conductive tape to the tab portion. Further, by using a conductive tape that is easily deformable (has flexibility) as the conductive material, the bending of the tab portion is less likely to be hindered. For this reason, even when the tab portion is bent and connected to the current collector, the tab portion and the current collector can be easily connected. If the conductive material is difficult to deform, the tab portion may be damaged at the boundary between the portion that is in contact with the conductive material and the portion that is not in contact with the tab portion. For this reason, damage to the tab portion can be suppressed by using an easily deformable conductive tape as the conductive material.

  Further, the conductive material may be further disposed in contact with the current collector.

  According to this, since the conductive path is shortened when the conductive material also contacts the current collector, the electrical resistance between the electrode body and the current collector can be further reduced.

  Further, the tab portion and the conductive material are integrally formed, and the conductive material is arranged in contact with the tab portion in a state of being bent with respect to the tab portion. Good.

  According to this, since the tab portion and the conductive material are integrally formed, the cross-sectional area of the conductor between the electrode body and the current collector can be increased without using a separate member. For this reason, for example, an electrical storage element can be manufactured efficiently.

  Further, the conductive material includes two conductive portions connected to the tab portion, and the two conductive portions are arranged to face each other with the tab portion sandwiched in a state of being bent with respect to the tab portion. You may decide that

  According to this, when welding the connection part of a tab part and a collector, for example, it can weld with a tab part and a collector, without removing a conductive part. For this reason, an electrical storage element can be manufactured efficiently.

  The conductive material may be joined to the tab portion.

  According to this, since the conductive material is joined to the tab portion, the electrical connection between the conductive material and the tab portion becomes more reliable. For this reason, a current flows more effectively to the conductive material, and the electrical resistance between the electrode body and the current collector can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage element which can reduce the electrical resistance between an electrode body and a collector can be provided.

1 is a perspective view schematically showing an external appearance of a power storage element according to Embodiment 1. FIG. FIG. 3 is a perspective view showing components arranged inside the container of the energy storage device according to Embodiment 1. 3 is a perspective view showing a configuration of an electrode body according to Embodiment 1. FIG. FIG. 2 is a perspective view showing configurations of an electrode body and a conductive material in Embodiment 1, and an enlarged view of a main part of the perspective view. FIG. 4 is a diagram showing a part of the assembly process (assembly method) for the energy storage device according to the first embodiment. FIG. 6 is a cross-sectional view in the vicinity of a tab portion, a conductive material, and a negative electrode current collector, taken along line VI-VI in FIG. 5. FIG. 6 is a cross-sectional view of the vicinity of a tab portion, a conductive material, and a negative electrode current collector in Modification 1 of Embodiment 1. FIG. 10 is a cross-sectional view of the vicinity of a tab portion, a conductive material, and a negative electrode current collector in Modification 2 of Embodiment 1. FIG. 11 is a cross-sectional view of the vicinity of a tab portion, a conductive material, and a negative electrode current collector in Modification 3 of Embodiment 1. FIG. 10 is a cross-sectional view of the vicinity of a tab portion, a conductive material, and a negative electrode current collector in Modification 4 of Embodiment 1. 5 is a perspective view showing a configuration of an electrode body according to Embodiment 2. FIG. In Embodiment 2, it is a figure which shows a mode that a tab part is connected to a negative electrode collector. 6 is a cross-sectional view of the vicinity of a tab portion and a negative electrode current collector in Embodiment 2. FIG. FIG. 10 is an enlarged perspective view of the vicinity of a tab portion in Modification 1 of Embodiment 2. FIG. 10 is a cross-sectional view of the vicinity of a tab portion and a negative electrode current collector in Modification 1 of Embodiment 2. 10 is an enlarged perspective view of the vicinity of a tab portion in Modification 2 of Embodiment 2. FIG. It is sectional drawing of the tab part in another embodiment, a electrically conductive material, and negative electrode collector vicinity.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, assembling steps and their order shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements that constitute a more preferable embodiment. Moreover, in each figure, a dimension etc. do not correspond exactly | strictly.

(Embodiment 1)
First, the structure of the electrical storage element 10 is demonstrated in detail.

  FIG. 1 is a perspective view schematically showing the external appearance of the energy storage device 10 according to the first embodiment. FIG. 2 is a perspective view showing components disposed inside the container 100 of the energy storage device 10 according to the first embodiment. Specifically, FIG. 2 is a perspective view illustrating a configuration in a state where the main body 111 of the container 100 is separated from the power storage element 10. FIG. 3 is a perspective view showing the configuration of the electrode assembly 400 according to Embodiment 1. FIG. 2 is a developed view of the bent state of the tab portions 411 and 421 of the electrode body 400. FIG. 3 is a partially developed view of the wound state of the electrode assembly 400 shown in FIG. 2, and shows a state before the tab portions 411 and 421 are gathered together.

  In FIG. 1 and the subsequent drawings, for convenience of explanation, the Z-axis direction is shown as the vertical direction, and there are places where the Z-axis direction is described as the vertical direction. The axial direction is not always the vertical direction.

  The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. For example, the electric storage element 10 is applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or the like. In addition, the electrical storage element 10 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it.

  As shown in FIG. 1, the electricity storage device 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300. As shown in FIG. 2, a positive electrode current collector 120, a negative electrode current collector 130, a spacer 140, and an electrode body 400 are accommodated (contained) inside the container 100.

  In addition to the above-described components, other spacers disposed between the electrode body 400 and the inner wall of the container 100, an insulating film that wraps the electrode body 400, or the like may be disposed. In addition, a liquid such as an electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100 of the electricity storage element 10, but the illustration of the liquid is omitted. In addition, as long as the electrolyte solution enclosed with the container 100 does not impair the performance of the electrical storage element 10, there is no restriction | limiting in particular in the kind, Various things can be selected.

  The container 100 includes a main body 111 having a long cylindrical shape and a bottom, and a lid 110 that is a plate-like member that closes an opening of the main body 111. In addition, the container 100 can be hermetically sealed by welding the lid body 110 and the main body 111 after the electrode body 400 and the like are accommodated therein. The material of the lid 110 and the main body 111 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, or aluminum alloy.

  The container 100 is provided with a safety valve 150 for releasing the pressure when the pressure in the container 100 increases. In the present embodiment, the safety valve 150 is disposed between the positive terminal 200 and the negative terminal 300 of the lid 110.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400 via the positive electrode current collector 120, and the negative electrode terminal 300 is the negative electrode of the electrode body 400 via the negative electrode current collector 130. The electrode terminal is electrically connected to. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 400 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 400, It is an electrode terminal made of metal for introducing. Further, the positive electrode terminal 200 and the negative electrode terminal 300 are attached to the lid body 110 disposed above the electrode body 400. The positive electrode terminal 200 and the negative electrode terminal 300 are formed of aluminum or an aluminum alloy.

  The positive electrode current collector 120 is a member that is disposed between the electrode body 400 and the container 100 and has electrical conductivity and rigidity that connects the electrode body 400 and the positive electrode terminal 200. Specifically, the positive electrode current collector 120 is disposed between a tab portion 411 (described later) on the positive electrode side of the electrode body 400 and the lid 110, and is joined to the tab portion 411 by welding or the like. And a joint portion 122 joined to the positive electrode terminal 200 by welding or the like. The positive electrode current collector 120 is made of aluminum or an aluminum alloy, as in the positive electrode current collector foil (positive electrode base material layer).

  The negative electrode current collector 130 is a member that is disposed between the electrode body 400 and the container 100 and has conductivity and rigidity that connects the electrode body 400 and the negative electrode terminal 300. Specifically, the negative electrode current collector 130 is disposed between a tab portion 421 (described later) on the negative electrode side of the electrode body 400 and the lid body 110, and is joined to the tab portion 421 by welding or the like. And a joining portion 132 joined to the negative terminal 300 by welding or the like. The negative electrode current collector 130 is made of copper or a copper alloy or the like, similarly to the negative electrode current collector foil (negative electrode base material layer).

  The spacer 140 is a member that is disposed between the electrode body 400 and the container 100 and is formed of a resin or the like that insulates the electrode body 400 and the container 100. The spacer 140 is formed of an insulating resin such as polycarbonate or polypropylene (PP), but may be formed of any material as long as the member has an insulating property.

  The spacer 140 is provided with notches 141 and 142 at the edge or the like. The tab portion 411 is joined to the joint portion 121 of the positive electrode current collector 120 in a state where the tab portion 411 is inserted through the notch portion 141 and pulled out upward (Z-axis direction plus side). On the other hand, the tab portion 421 is joined to the joining portion 131 of the negative electrode current collector 130 in a state where the tab portion 421 is inserted through the notch portion 142 and pulled out upward (Z-axis direction plus side). The notch 141 and the notch 142 are formed independently of each other and are not connected. For this reason, the insulation of the tab part 411 penetrated by the notch part 141 and the tab part 421 penetrated by the notch part 142 is securable.

  Further, the spacer 140 is provided with a through hole 143 at a position facing the safety valve 150. In the present embodiment, the through hole 143 is provided below the safety valve 150 (Z-axis direction minus side). By providing the through-hole 143 at a position facing the safety valve 150 in this way, when the internal pressure of the container 100 increases, the internal gas can be quickly exhausted from the safety valve 150 to the outside of the container. it can.

  The electrode body 400 is a power generation element capable of storing electricity, and includes a positive electrode 410, a negative electrode 420, and a separator 430 as shown in FIG. 3, and the positive electrode 410, the negative electrode 420, and the separator 430 are arranged in the X-axis direction and the Y direction. It is formed by being laminated in the axial direction. Specifically, the electrode body 400 is a wound electrode body formed by winding a positive electrode 410, a negative electrode 420, and a separator 430, and is electrically connected to the positive electrode current collector 120 and the negative electrode current collector 130. Connected.

The positive electrode 410 is an electrode plate in which a positive electrode active material layer is formed on the surface of a positive electrode base material layer that is a long strip-shaped metal foil made of aluminum or an aluminum alloy. In addition, as a positive electrode active material used for a positive electrode active material layer, if it is a positive electrode active material which can occlude / release lithium ion, a well-known material can be used suitably. For example, as a positive electrode active material, a polyanion compound such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, Spinel compounds such as lithium manganate, lithium transition metal oxides such as LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) and the like can be used.

The negative electrode 420 is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode base material layer that is a long strip-shaped metal foil made of copper, a copper alloy, or the like. In addition, as a negative electrode active material used for a negative electrode active material layer, if it is a negative electrode active material which can occlude-release lithium ion, a well-known material can be used suitably. For example, as the negative electrode active material, lithium metal, lithium alloy (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloy), and lithium can be used. Alloys that can be occluded / released, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₅ O _12, etc.) ) And polyphosphoric acid compounds.

  The separator 430 is a microporous sheet made of resin. Note that the separator 430 used in the power storage element 10 is not particularly different from that conventionally used, and any known material can be used as long as it does not impair the performance of the power storage element 10. Further, as the electrolytic solution (nonaqueous electrolyte) sealed in the container 100, there is no particular limitation on the type thereof as long as it does not impair the performance of the power storage element 10, and various types can be selected.

  The electrode body 400 is formed by winding a layered arrangement so that the separator 430 is sandwiched between the positive electrode 410 and the negative electrode 420. The positive electrode 410 and the negative electrode 420 have a portion where the active material is not applied and the base material layer is exposed (the active material layer is not formed) at one end in the winding axis direction (end on the positive side in the Z-axis direction) Active material layer non-forming part), and a part of the portion where the base material layer is exposed is provided so as to protrude outward. In other words, a part of the portion where the base material layer is exposed is formed to be drawn outward. Specifically, the positive electrode 410 has a plurality of protrusions 411a that protrude outward at one end in the winding axis direction, and the negative electrode 420 similarly has a plurality of protrusions that protrude outward at one end in the winding axis direction. It has a protrusion 421a.

  Note that the winding axis is a virtual axis serving as a central axis when winding the positive electrode 410, the negative electrode 420, and the like. In this embodiment, the winding axis is parallel to the Z-axis direction passing through the center of the electrode body 400. It is a straight line.

  The plurality of protrusions 411a and the plurality of protrusions 421a are arranged at the same end in the winding axis direction, and are stacked at a predetermined position of the electrode body 400 by stacking the positive electrode 410 and the negative electrode 420. . Specifically, the plurality of projecting portions 411a are stacked at predetermined positions in the circumferential direction at one end in the winding axis direction by stacking the positive electrode 410 by winding. The plurality of protrusions 421a are stacked at predetermined positions in the circumferential direction different from the position where the plurality of protrusions 411a are stacked at one end in the winding axis direction by stacking the negative electrode 420 by winding. Is done.

  Accordingly, in the electrode body 400 formed by winding the positive electrode 410, the negative electrode 420, and the separator 430, the tab portion 411 formed by stacking the plurality of protruding portions 411a and the plurality of protruding portions 421a are stacked. And a tab portion 421 formed as a result. Each of the tab portions 411 and 412 is gathered toward the center in the stacking direction, for example, and inserted into the notches 141 and 142 of the spacer 140, and the joint portion 121 and the negative electrode of the positive electrode current collector 120 are inserted. It is joined to the joining portion 131 of the current collector 130.

  As described above, the electrode body 400 includes tab portions 411 and 421 that protrude outward and are connected to the positive electrode current collector 120 and the negative electrode current collector 130. Such tab portions 411 and 421 are formed by laminating portions where the active material is not applied and the base material layer is exposed. That is, the tab portions 411 and 421 are exposed metal foil laminates and are portions that do not contribute to power generation. On the other hand, since the portions other than the tab portions 411 and 421 of the electrode body 400 are formed by laminating a portion coated with an active material on the base material layer, the portion contributes to power generation. . Hereinafter, this part is referred to as a power generation part 401.

  Here, as shown in FIG. 2, the electric storage element 10 further includes conductive materials 510 and 520 arranged in contact with the tab portions 411 and 421. Specifically, the conductive material 510 is disposed in contact with the tab portion 411, and the conductive material 520 is disposed in contact with the tab portion 421.

  Hereinafter, the structure regarding the tab portions 411 and 421 and the conductive materials 510 and 520 in the present embodiment will be further described with reference to FIGS. In the present embodiment, the positive electrode side member (tab portion 411 and conductive material 510) and the negative electrode side member (tab portion 421 and conductive material 520) have the same configuration. For this reason, below, the structure regarding the member on the negative electrode side is mainly demonstrated, and the matter regarding the member on the positive electrode side is simplified and demonstrated.

  FIG. 4 is a perspective view showing a configuration of the electrode body 400 and the conductive materials 510 and 520 in the present embodiment, and an enlarged view of a main part of the perspective view. FIG. 5 is a diagram showing a part of the assembly process (assembly method) of power storage element 10 according to the present embodiment. Specifically, FIG. 4 is a diagram illustrating a process of assembling the electrode body 400 and the lid body 110 in the assembly process of the power storage element 10. FIG. 6 is a cross-sectional view of the vicinity of the tab portion 421, the conductive material 520, and the negative electrode current collector 130 taken along the line VI-VI in FIG. 4 is a developed view of the bent portions of the tab portions 411 and 421 of the electrode body 400, and the positive electrode 410 and the separator 430 of the electrode body 400 are not shown in the enlarged view. In FIG. 5A, dots are hatched at connection portions between the tab portions 411 and 421, the positive electrode current collector 120 and the negative electrode current collector 130, and FIG. 5C shows the lid 110 and the like. It is a perspective view. 5 and 6, the illustration of the spacer 140 is omitted. In FIG. 6, a virtual winding axis W of the electrode body 400 is indicated by a broken line.

  As shown in FIG. 4, the tab portion 421 is arranged in a state in which a plurality of protruding portions 421 a are gathered toward the center in the stacking direction (Y-axis direction in FIG. 4) and are in close contact with each other in the stacking direction. . For this reason, the tab part 421 becomes one conductor when the laminated body of metal foils adheres.

  A conductive material 520 is in contact with the tab portion 421. Specifically, the conductive material 520 is disposed so as to surround the outer periphery of the tab portion 421, and more specifically, is disposed so as to surround the entire outer periphery.

  In the present embodiment, the conductive material 520 is a conductive tape such as a carbon tape that is attached to the tab portion 421. The same applies to the conductive material 510 on the positive electrode side. Thus, by using a conductive tape as the conductive material 520, for example, when the conductive tape has adhesiveness, it can be easily attached to the tab portion 421. Note that the conductive tape may not have adhesiveness, and may be attached to the tab portion 421 with, for example, a conductive bonding material.

  Further, the conductive material 520 is not limited to a carbon tape but may be a metal tape (Al tape or Cu tape). In this case, the metal used for the metal tape prevents dissolution and precipitation of the metal. From the viewpoint, it is preferable that the material is the same as the material of the tab portions 411 and 421 to which the metal tape is attached. Specifically, the metal tape attached to the tab 411 on the positive electrode side is made of aluminum or aluminum alloy that is the material of the metal foil of the positive electrode 410, and the metal tape attached to the tab 421 on the negative electrode side is It is preferable that the negative electrode 420 is made of a metal foil material such as copper or copper alloy.

  On the other hand, the carbon tape is less likely to cause metal dissolution and precipitation, and therefore can be used for both the positive electrode tab portion 411 and the negative electrode tab portion 421.

  Next, assembly of the electrode body 400 and the lid body 110 will be described.

  First, as shown in FIG. 4, a conductive material 520 is attached to the tab portion 421.

  Next, as shown in FIG. 5A, the tab portion 421 to which the conductive material 520 is attached is joined to the negative electrode current collector 130 by, for example, ultrasonic welding. Thereby, the negative electrode 420 of the electrode body 400 is structurally and electrically connected to the negative electrode current collector 130. The tab portion 421 and the negative electrode current collector 130 may be connected by welding other than ultrasonic welding such as resistance welding or mechanical joining such as mechanical caulking.

  Here, the distance from the end face of the power generation portion 401 on the tab portion 421 side to the connection portion C (for example, a welding position or a caulking position) between the tab portion 421 and the negative electrode current collector 130 is the size of the electrode body 400 or the like. It is prescribed by. For this reason, the length of the tab portion 421 (the size in the Z-axis direction in FIG. 5A) only needs to be a specified distance and the size of the connection portion C, and may not be longer than necessary. .

  Moreover, also about the negative electrode collector 130, the junction part 131 should just be larger than the connection part C, and does not need to be larger than necessary. For this reason, the joint portion 131 can be reduced in size, and in this embodiment, the negative electrode current collector 130 is formed in a bent flat plate shape in which some corners of a substantially long rectangle are cut out. . That is, the negative electrode current collector 130 is formed such that the bonding portion 131 is smaller than the bonding portion 132 in the short direction. As described above, in the present embodiment, the negative electrode current collector 130 is reduced in weight by providing notches in unnecessary portions of the negative electrode current collector 130 (in this embodiment, some corners). Yes.

  Further, the tab portion 421 and the negative electrode current collector 130 are aligned and joined by, for example, a jig or the like. At this time, the notch is provided in the negative electrode current collector 130, thereby aligning the corner formed by the notch of the negative electrode current collector 130 with the corner of the tip of the tab portion 421. It doesn't matter.

  Next, as shown in FIG. 5B, the negative electrode current collector 130 and the negative electrode terminal 300 are connected by, for example, mechanical caulking or the like with the lid 110 sandwiched therebetween.

  Thereafter, the tip end side of the tab portion 421 is rotated and bent in a predetermined direction by a virtual rotation axis F1 shown in FIG. 5B, and the tab is further turned by a virtual rotation axis F2 shown in FIG. The distal end side of the part 421 is turned and bent in the direction opposite to the predetermined direction, and the spacer 140 is assembled to assemble the electrode body 400, the lid body 110, and the like as shown in FIG.

  As a result, as shown in FIG. 6, the tab portion 421 is connected to the negative electrode current collector 130 by being attached with the conductive material 520 and bent at two locations. As described above, in the present embodiment, the tab portion 421 is bent at two locations, so that the length of the tab portion 421 can be increased as compared with a configuration bent at one location, for example. For this reason, the workability | operativity at the time of connecting the negative electrode collector 130 and the negative electrode terminal 300 improves. In addition, since an appropriate sag occurs in the tab portion 421 in the container 100, the stress applied to the electrode body 400 and the like when the power storage element 10 vibrates can be absorbed by the sag. Therefore, damage to the electrode body 400 can be suppressed.

  Further, since the tab portion 421 is a laminated body of metal foil, when bent at a portion where the conductive material 520 is attached, the tab portion 421 is bent in a state in which movement is restricted by the conductive material 520. There is a risk that excessive stress will be applied. This can be a factor such as an unexpected tear of the metal foil. For this reason, bending | flexion of the tab part 421 with the rotating shafts F1 and F2 different from the part to which the electrically conductive material 520 was affixed suppresses generation | occurrence | production of malfunctions, such as peeling of metal foil. That is, the conductive material 520 is disposed in contact with a position different from the bent portion of the tab portion 421.

  Here, in general, according to the electricity storage device in which the active material is not applied and the portion where the base material layer is exposed is drawn to form a tab portion and a current collector is attached to the tab portion, The volume of the portion (power generation portion) that contributes to the power can be increased. For this reason, the structure of the electrical storage element which provides a tab part from a viewpoint of the capacity increase of an electrical storage element is preferable.

  In addition, a current flows between the electrode body and the current collector as the storage element is charged and discharged. For this reason, in order to quickly charge and discharge the power storage element, it is desired to reduce the resistance between the electrode body and the current collector. That is, in the structure of the power storage element provided with the tab portion, the resistance between the electrode body and the current collector is reduced by increasing the width of the tab portion (size perpendicular to the pulling direction of the tab portion). Configuration is conceivable.

  However, the width of the tab portion is formed smaller than the width of the electrode body (power generation portion). Further, when viewed in the stacking direction, the positive electrode tab portion and the negative electrode tab portion are arranged on the same side of the electrode body (on the same side in the winding axis direction in the case of the wound electrode body), the positive electrode From the viewpoint of ensuring insulation between the tab portion on the side and the tab portion on the negative electrode side, each tab portion is formed with a limited width or less (for example, less than half the width of the electrode body). Further, in order to quickly exhaust the safety valve, when the tab portion is formed avoiding the position where the safety valve is disposed, the width of the tab portion is further limited.

  Thus, in the structure of the electrical storage element provided with the tab portion, it is difficult to reduce the resistance between the electrode body and the current collector because the width of the tab portion is limited. For this reason, in this configuration, it may be difficult to realize a high output (high rate) power storage element.

  Therefore, in the present embodiment, as described above, the conductive material 510 is disposed in contact with the tab portion 411, and the conductive material 520 is disposed in contact with the tab portion 421, thereby providing the effects described below. Can be played. In the following, the effect of the negative electrode side member (conductive material 520 and tab portion 421) will be described, but the same applies to the positive electrode side member (conductive material 510 and tab portion 411).

  That is, according to the present embodiment, the conductive material 520 is disposed in contact with the tab portion 421, thereby increasing the cross-sectional area of the conductor between the electrode body 400 and the negative electrode current collector 130. Can do. Therefore, since the electrical resistance between the electrode body 400 and the negative electrode current collector 130 can be reduced, a high-output (high rate) power storage element can be realized. Further, since the tab portion 421 is reinforced by the conductive material 520, damage to the tab portion 421 can be suppressed. Therefore, the highly reliable power storage element 10 can be realized.

  Specifically, since the conductive material 520 is disposed in contact with the tab portion 421, a current flowing between the electrode body 400 and the negative electrode current collector 130 is not only transmitted to the tab portion 421 but also to the conductive material 520. Will also flow. That is, the resistance between the electrode body 400 and the negative electrode current collector 130 can be reduced as compared with the case where the current flows only through the tab portion 421.

  More specifically, at a portion where the conductive material 520 is in contact with the tab portion 421, the portion is cut in the thickness direction (cut along the XZ plane in FIG. 6 or cut along a plane perpendicular to the direction in which the current flows). ) Increases in cross-sectional area as compared with the case where the conductive material 520 is not in contact with the tab portion 421. For this reason, since the resistance of the portion can be reduced, the overall resistance between the electrode body 400 and the negative electrode current collector 130 can also be reduced.

  In addition, according to the present embodiment, the outer periphery of the tab portion 421 is surrounded by the conductive material 520, thereby further increasing the cross-sectional area of the conductor between the electrode body 400 and the negative electrode current collector 130. Can do. Therefore, since the electrical resistance between the electrode body 400 and the negative electrode current collector 130 can be further reduced, the power storage element 10 with higher output can be realized.

  Further, according to the present embodiment, since the conductive material 520 is the conductive tape that is attached to the tab portion 421, the cross-sectional area of the conductor between the electrode body 400 and the current collector can be easily increased. Can be made. In addition, when a conductive tape that is easily deformable (has flexibility) is used as the conductive material 520, it is difficult to prevent the tab portion 421 from being bent. Therefore, the tab portion 421 is bent and connected to the current collector. Even so, the tab portion 421 and the current collector can be easily connected. Further, when the conductive material 520 is difficult to deform, the tab portion 421 may be damaged by tearing or the like at the boundary between the portion in contact with the conductive material 520 and the portion not in contact with the tab portion 421. For this reason, damage to the tab portion 421 can be suppressed by using an easily deformable conductive tape as the conductive material 520.

  As shown in FIGS. 2 and 5, the conductive material 520 is disposed at a position different from that between the safety valve 150 and the electrode body 400. Specifically, the conductive material 520 is disposed at a position other than between the safety valve 150 and the power generation portion 401 of the electrode body 400. That is, in the container 100, the conductive material 520 is not located directly below the safety valve 150 (in FIG. 2 and FIG. 5, the Z axis direction minus side).

  As described above, according to the present embodiment, the conductive material 520 is disposed in a portion different from between the safety valve 150 and the electrode body 400, whereby the pressure is released when the pressure in the container 100 increases. Can be difficult to disturb. That is, the gas in the container 100 can be quickly discharged out of the container 100.

  The arrangement position of the conductive material with respect to the tab part, the bending form of the tab part, and the like may be different from those of the first embodiment. Accordingly, various modifications of the first embodiment will be described below with reference to FIGS. In the following, modifications of the negative electrode side member (conductive material, tab portion, etc.) will be described, but the same applies to the positive electrode side member. 7 to 11 are cross-sectional views of the storage element according to each modification corresponding to the VI-VI line in FIG. 5. In these drawings, the spacer 140 is not shown and the electrode body 400 is not shown. A virtual winding axis W is indicated by a broken line.

(Modification 1 of Embodiment 1)
FIG. 7 is a cross-sectional view of the vicinity of the tab portion 421, the conductive material 520A, and the negative electrode current collector 130 in Modification 1 of Embodiment 1.

  In the first embodiment, the conductive material 520 is disposed so as to surround the outer periphery of the tab portion 421. However, the conductive material only needs to be disposed in contact with the tab portion 421. For example, the conductive material 520A does not have to surround the outer periphery of the tab portion 421 as shown in FIG. That is, the conductive material 520 </ b> A only needs to be disposed in contact with a part of the outer peripheral surface of the tab portion 421.

  According to such a configuration, although it is somewhat inferior to the first embodiment, the conductive material 520A is disposed in contact with the tab portion 421, so that the conductivity between the electrode body 400 and the negative electrode current collector 130 is increased. Since the cross-sectional area of the body can be increased, the electrical resistance between the electrode body 400 and the negative electrode current collector 130 can be reduced.

(Modification 2 of Embodiment 1)
FIG. 8 is a cross-sectional view of the vicinity of the tab portion 421A, the conductive material 520, and the negative electrode current collector 130 in the second modification of the first embodiment.

  In the first embodiment, the tab portion 421 is bent at two locations and connected to the negative electrode current collector 130. However, the connection form between the tab portion and the negative electrode current collector 130 is not limited to this. For example, as shown in FIG. 8, the tab portion 421A is bent at one location and connected to the negative electrode current collector 130. It doesn't matter.

  At this time, the conductive material 520 may be disposed in contact with the tab portion 421A so as to surround the outer periphery of the tab portion 421A.

  According to such a configuration, as in Embodiment 1, the conductive material 520 is disposed so as to surround the outer periphery of the tab portion 421A, whereby the conductor between the electrode body 400 and the negative electrode current collector 130 is disposed. Since the cross-sectional area can be increased, the electrical resistance between the electrode body 400 and the negative electrode current collector 130 can be reduced.

  Further, according to such a configuration, the tab portion 421A is bent at one location and connected to the negative electrode current collector 130, whereby the length of the tab portion 421A can be made shorter than that of the first embodiment. For this reason, since the width of the electrode plate of the negative electrode 420 (the size in the winding axis direction before the tab portion 421 is bent) can be reduced, the mass production efficiency of the negative electrode 420 can be improved.

(Modification 3 of Embodiment 1)
FIG. 9 is a cross-sectional view of the vicinity of the tab portion 421A, the conductive material 520C, and the negative electrode current collector 130C in the third modification of the first embodiment.

  The negative electrode current collector 130C shown in the figure has a width (a size in the Y-axis direction in FIG. 9) of the joining portion 131C connected to the tab portion 421A, compared to the joining portion 131 of the negative electrode current collector 130 in the first embodiment. A) is formed large. That is, the notch provided in the negative electrode current collector 130 in the first embodiment is not provided in the negative electrode current collector 130C in the present modification.

  As a result, the conductive material 520C shown in the figure is further disposed in contact with the negative electrode current collector 130C as compared with the conductive material 520 in the first embodiment. That is, the tab portion 421A is connected to the negative electrode current collector 130 at the tip portion, and is connected to the negative electrode current collector 130 via the conductive material 520C at a portion closer to the power generation portion 401 than the tip portion.

  According to such a configuration, the conductive material 520C also contacts the negative electrode current collector 130C, whereby a conductive path between the electrode body 400 and the negative electrode current collector 130C (between the power generation portion 401 and the negative electrode current collector 130). Current path) is shortened, and the electrical resistance between the electrode body 400 and the negative electrode current collector 130C can be further reduced.

  Note that the width and shape of the negative electrode current collector 130C and the conductive material 520C are not particularly limited, and the power generation portion is more than the connection portion between the tab portion 421A and the negative electrode current collector 130 (the tip portion of the tab portion 421A in this modification). On the 401 side, the conductive material 520C may be sandwiched between the negative electrode current collector 130C and the tab portion 421A.

(Modification 4 of Embodiment 1)
Further, the conductive material arranged in contact with the tab portion 421A may not be a conductive tape. Hereinafter, a configuration using a metal cover as the conductive material will be described with reference to FIG.

  FIG. 10 is a cross-sectional view of the vicinity of the tab portion 421A, the conductive material 520D, and the negative electrode current collector 130 in the fourth modification of the first embodiment.

  A conductive material 520D shown in the figure is a metal cover disposed in contact with the tab portion 421A, and is, for example, a flat metal member. The conductive material 520D is made of, for example, copper or a copper alloy that is a material of the metal foil of the negative electrode 420, similarly to the conductive material 520 of the first embodiment. For example, the conductive material 520D is disposed in contact with the tab portion 421A by being joined to the tab portion 421A in the X11 portion in FIG.

  Note that a method of joining the tab portion 421 and the conductive material 520D is not particularly limited, and material bonding such as fusion bonding and interface bonding, or mechanical bonding is employed. The fusion joining is a joining method in which the joining base material is actively melted, and for example, laser welding, electron beam welding, resistance welding, or the like is employed. The interfacial bonding is a bonding method that does not involve melting of the base material or limits the base material melting to a local portion, and for example, ultrasonic bonding or friction bonding is employed. The mechanical joining is also referred to as mechanical joining, and for example, caulking such as clinch caulking or rivet caulking is adopted.

  As described above, even in the configuration having the metal cover as the conductive material 520D, the conductive material 520D is disposed in contact with the tab portion 421A so that the electrode body 400 and the negative electrode current collector 130A are disposed. Therefore, the electrical resistance between the electrode body 400 and the negative electrode current collector 130A can be reduced.

  Further, according to the present modification, the conductive material 520D is joined to the tab portion 421, so that the electrical connection between the conductive material 520D and the tab portion 421 becomes more reliable. For this reason, a current flows more effectively through the conductive material 520D, and the electrical resistance between the electrode body 400 and the negative electrode current collector 130A can be further reduced.

(Embodiment 2)
Next, a second embodiment will be described. In the above embodiment, the conductive material arranged in contact with the tab portion is a member separate from the tab portion. In contrast, in the present embodiment, the tab portion and the conductive material are integrally formed, and the conductive material is disposed in contact with the tab portion in a state of being bent with respect to the tab portion. . That is, the conductive material is formed of a laminated body of metal foils, like the tab portion.

  FIG. 11 is a perspective view showing the configuration of the electrode body 400H according to the second embodiment. FIG. 11 is a partially developed view of the wound state of the electrode body 400H, and shows a state before the tab portions 411H and 421H are gathered and bent.

  The positive electrode 410H shown in the figure is different from the positive electrode 410 in Embodiment 1 in the shape of the protruding portion 411h. Specifically, in the present embodiment, the protruding portion 411h is formed in a substantially T shape. Similarly, the negative electrode 420H has a protruding portion 421h formed in a substantially T shape.

  Thus, in the present embodiment, the positive electrode 410H is formed by stacking a plurality of protrusions 411h, and has a substantially T-shape when viewed in the stacking direction (as viewed in the Y-axis direction in FIG. 11). A tab portion 411H is provided. Similarly, the negative electrode 420H is formed by laminating a plurality of protruding portions 421h, and has a substantially T-shaped tab portion 421H when viewed in the laminating direction.

  Hereinafter, the configuration related to the tab portions 411H and 421H and the conductive materials 510 and 520 in the present embodiment will be further described with reference to FIGS. In the present embodiment, the positive electrode side member (tab portion 411H and conductive material 510) and the negative electrode side member (tab portion 421H and conductive material 520) have the same configuration. For this reason, below, the structure regarding the member on the negative electrode side is mainly demonstrated, and the matter regarding the member on the positive electrode side is simplified and demonstrated.

  FIG. 12 is a diagram showing how the tab portion 421H is connected to the negative electrode current collector 130 in the present embodiment. FIG. 13 is a cross-sectional view of the vicinity of the tab portion 421H and the negative electrode current collector 130 in the present embodiment. Specifically, FIG. 13 is a cross-sectional view of a power storage element according to this modification corresponding to the VI-VI line of FIG. 5, in which the illustration of the spacer 140 is omitted, and the virtual view of the electrode body 400H is shown. A typical winding axis W is indicated by a broken line.

  As shown in FIG. 12A, the tab portion 421 </ b> H having a substantially T shape as viewed in the stacking direction includes a first conductive portion 441 that protrudes outward from the power generation portion 401, and a tip of the first conductive portion 441. Two conductive portions (second conductive portions 442a and 442b) connected to the portion.

  The first conductive portion 441 corresponds to the tab portion 421 in the first embodiment, and is a laminated body of metal foil that forms a substantially T-shaped vertical line formed by the tab portion 421H.

  The second conductive portions 442a and 442b are formed integrally with the first conductive portion 441, and have a substantially T-shaped horizontal line formed by the tab portion 421H protruding in the opposite direction at the tip of the first conductive portion 441. It is the laminated body of the metal foil to comprise. The width of the second conductive portion 442a (the size in the X-axis direction in FIG. 12A) is equal to the width of the second conductive portion 442b. However, the present invention is not limited to this, and one may be larger than the other. Absent.

  The tab portion 421H formed in this way is connected to the negative electrode current collector 130 as follows.

  First, as shown in FIG. 12A, each of the second conductive portions 442 a and 442 b is bent with respect to the first conductive portion 441. Accordingly, as shown in FIG. 12B, each of the second conductive portions 442a and 442b is arranged in contact with the first conductive portion 441 in a state where the second conductive portions 442a and 442b are bent with respect to the first conductive portion 441. The

  At this time, the second conductive portion 442a and the second conductive portion 442b are bent in directions opposite to each other with respect to the first conductive portion 441. For this reason, as shown in FIG. 12B, the two conductive portions (second conductive portions 442a and 442b) are bent with respect to the first conductive portion 441 and the first conductive portion 441 is moved. They are placed opposite to each other. That is, the second conductive portion 442a and the second conductive portion 442b are bent to the opposite side. Specifically, when viewed from above (as viewed from the plus side in the Z-axis direction in FIG. 12), both the second conductive portion 442a and the second conductive portion 442b are counterclockwise (counterclockwise) with respect to the first conductive portion 441. Around). Thus, the second conductive portions 442a and 442b are arranged so as to sandwich the first conductive portion 441 from both sides in the Y-axis direction.

  The tab portion 421H bent in this way is joined to the negative electrode current collector 130 by, for example, ultrasonic welding at the connection portion C, as shown in FIG. Thereby, the negative electrode 420H of the electrode body 400H is structurally and electrically connected to the negative electrode current collector 130. Note that the tab portion 421H and the negative electrode current collector 130 may be connected by welding other than ultrasonic welding such as resistance welding, or mechanical joining such as mechanical caulking.

  Here, as described in the first embodiment, the distance from the end face of the power generation portion 401 on the tab portion 421H side to the connection portion C is defined by the size of the electrode body 400H and the like. For this reason, the length of the first conductive portion 441 (the size in the Z-axis direction in FIG. 12) only needs to be the distance specified and the size of the connection portion C, and may not be larger than necessary.

  The size of the second conductive portions 442a and 442b is not limited as long as it can cover the connection portion C in a bent state.

  The tab portion 421H connected to the negative electrode current collector 130 is connected to the negative electrode current collector 130 and the negative electrode terminal 300 with the lid 110 sandwiched therebetween, for example, by mechanical caulking, as in the first embodiment. After being bent, it is placed in the container 100 in a shape as shown in FIG. In Embodiment 1, the tab portion 421 is bent twice and disposed in the container 100. However, in this embodiment, the tab portion 421H is bent only once and disposed in the container 100. . In other words, the tab portion 421H is bent at a portion different from the portion where the second conductive portions 442a and 442b abut on the first conductive portion 441.

  Since each of the first conductive portion 441 and the second conductive portions 442a and 442b is a laminated body of metal foil, when the portion where the second conductive portions 442a and 442b abut on the first conductive portion 441 is bent, the bent portion Excessive stress may be applied to the outer metal foil. This can be a factor such as an unexpected tear of the metal foil. Therefore, in the present embodiment, the first conductive portion 441 is bent at a portion different from the portion where the second conductive portions 442a and 442b are in contact with each other, thereby suppressing the occurrence of problems such as peeling of the metal foil. .

  Note that the first conductive portion 441 and the second conductive portions 442a and 442b may be joined to a portion different from the connection portion C (for example, the X21 portion in FIG. 13). Thereby, the electrical connection between the second conductive portions 442a and 442b and the first conductive portion 441 becomes more reliable. For this reason, a current flows more effectively to the second conductive portions 442a and 442b, and the electrical resistance between the electrode body 400H and the negative electrode current collector 130 can be further reduced. In addition, the joining method of the metal foil which comprises the junction part of 1st electroconductive part 441 and 2nd electroconductive part 442a, 442b is the tab part 421 and the electrically conductive material 520D in the modification 4 of the said Embodiment 1. FIG. Similar to the bonding method, there is no particular limitation, and material bonding such as fusion bonding and interface bonding, or mechanical bonding is employed.

  Thus, the tab part 421H in this Embodiment has the 1st conductive part 441 and the 2nd conductive parts 442a and 442b comprised with the laminated body of metal foil. Here, as described above, the first conductive portion 441 corresponds to the tab portion 421 in the first embodiment. Moreover, since the 2nd electroconductive part 442a is a laminated body of metal foil, it is an electroconductive material which has electroconductivity. Similarly, the second conductive portion 442b is also a conductive material. That is, the conductive material in the present embodiment includes two conductive portions (second conductive portions 442a and 442b) connected to the first conductive portion 441.

  Even in such a configuration, the second conductive portions 442a and 442b are arranged in contact with the first conductive portion 441 in a state where the second conductive portions 442a and 442b are bent with respect to the first conductive portion 441. 1, the electrical resistance between the electrode body 400H and the negative electrode current collector 130 can be reduced.

  Further, according to the present embodiment, the first conductive portion 441 corresponding to the tab portion 421 in the first embodiment and the second conductive portions 442a and 442b which are the conductive materials in the present embodiment are integrally formed. Yes. Thereby, the cross-sectional area of the conductor between the electrode body 400H and the negative electrode current collector 130 can be increased without using a separate member. For this reason, for example, an electrical storage element can be manufactured efficiently.

  Further, according to the present embodiment, the second conductive portions 442a and 442b are arranged to face each other with the first conductive portion 441 interposed therebetween, so that, for example, the first conductive portion 441 and the negative electrode current collector 130 are The second conductive portions 442a and 442b are less likely to be stepped off when welding the connection portion C, and can be welded together with the first conductive portion 441 and the negative electrode current collector 130. For this reason, an electrical storage element can be manufactured efficiently.

  That is, when the second conductive portions 442a and 442b are bent so as to be disposed on the same side of the first conductive portion 441, the overlapping area of the second conductive portions 442a and 442b is reduced depending on the thickness of the second conductive portions 442a and 442b. . On the other hand, when the second conductive portions 442a and 442b are arranged to face each other with the first conductive portion 441 interposed therebetween, the overlapping area of the second conductive portions 442a and 442b can be increased. For this reason, even if the connection part C is small, the stepping off of the second conductive parts 442a and 442b during welding can be suppressed.

  In the present embodiment, the second conductive portions 442a and 442b protrude at the tip of the first conductive portion 441. However, the protruding position is not particularly limited, and protrudes at the central portion of the first conductive portion 441. It doesn't matter.

  Note that the second conductive portion 442a and the second conductive portion 442b may be arranged on the same side of the first conductive portion 441 by being bent with respect to the first conductive portion 441.

  Further, according to the present embodiment, the tab portion 421H is formed so that the extending direction is different between the first conductive portion 441 and the second conductive portions 442a and 442b. For this reason, since the width of the electrode plate of the negative electrode 420H (the size in the winding axis direction before the tab portion 421J is bent) can be reduced, the mass production efficiency of the negative electrode 420 can be improved.

  The shape of the second conductive portion formed integrally with the first conductive portion 441, the bending form of the tab portion, and the like may be different from those of the second embodiment. Accordingly, various modifications in the second embodiment will be described below with reference to FIGS. In the following, modifications of the negative electrode side member (conductive material, tab portion, etc.) will be described, but the same applies to the positive electrode side member.

(Modification 1 of Embodiment 2)
FIG. 14 is an enlarged perspective view of the vicinity of the tab portion 421I in the first modification of the second embodiment. FIG. 15 is a cross-sectional view of the vicinity of the tab portion 421I and the negative electrode current collector 130 in Modification 1 of Embodiment 2. Specifically, FIG. 15 is a cross-sectional view of a power storage element according to this modification corresponding to the VI-VI line in FIG. 5, in which the illustration of the spacer 140 is omitted, and the virtual view of the electrode body 400I is shown. A typical winding axis W is indicated by a broken line. FIG. 14 shows a state before the tab portion 421I is gathered and bent.

  The electrode body 400I in this modification shown in these drawings is formed by winding a positive electrode 410I, a negative electrode 420I, and a separator 430, and a positive electrode tab is formed by a positive electrode tab portion (not shown) and a negative electrode tab portion 421I. It is electrically connected to the electric body 120 and the negative electrode current collector 130.

  The tab portion 421I has a configuration that does not include the second conductive portion 442b as compared with the tab portion 421 in the second embodiment. Therefore, the tab portion 421I is formed in a substantially L shape when viewed in the stacking direction.

  The tab portion 421I formed in this manner is brought into contact with the first conductive portion 441 in a state where the second conductive portion 442a is bent with respect to the first conductive portion 441 after being gathered in the thickness direction. Be placed. Thereafter, the tab portion 421I obtained by bending the second conductive portion 442a is bent after being joined to the negative electrode current collector 130 and disposed in the container 100 in a shape as shown in FIG.

  Even in such a configuration, the second conductive portion 442a is arranged in contact with the first conductive portion 441 in a state of being bent with respect to the first conductive portion 441, and thus, similarly to the second embodiment. The electrical resistance between the electrode body 400I and the negative electrode current collector 130 can be reduced.

  Note that the first conductive portion 441 and the second conductive portion 442a are different from a connection portion (not shown) to be joined to the negative electrode current collector 130 (for example, the X31 portion in FIG. 15) by, for example, ultrasonic welding. It may be done. Thereby, as in the second embodiment, the electrical resistance between the electrode body 400I and the negative electrode current collector 130 can be further reduced.

(Modification 2 of Embodiment 2)
FIG. 16 is an enlarged perspective view of the vicinity of the tab portion 421J in the second modification of the second embodiment.

  In Embodiment 2 and Modification 1 thereof, the tab portion is formed so that the extending direction is different between the first conductive portion and the second conductive portion. That is, the first conductive portion protruding from the power generation portion 401 of the electrode body and the second conductive portion protruding from the first conductive portion in a direction different from the protruding direction of the first conductive portion are included. On the other hand, the tab portion 421J in the present modification shown in FIG. 16 includes second conductive portions 442j and 442k that protrude from the distal end portion of the first conductive portion 441 in the same direction as the protruding direction of the first conductive portion. Therefore, the tab portion 421J is formed in a substantially I shape when viewed in the stacking direction.

  After the tab portions 421J formed in this way are gathered in the thickness direction, the second conductive portion 442j is bent with respect to the second conductive portion 442k, and the second conductive portion 442k is further bent into the first conductive portion 441. Is bent against. Accordingly, the second conductive portions 442j and 442k are arranged in contact with the first conductive portion 441 in a state where the second conductive portions 442j and 442k are bent with respect to the first conductive portion 441.

  Even in such a configuration, the second conductive portions 442j and 442k are arranged in contact with the first conductive portion 441 while being bent with respect to the first conductive portion 441. Similarly, the electrical resistance between the electrode body and the negative electrode current collector 130 can be reduced.

(Other embodiments)
The power storage device according to the embodiment of the present invention and the modification thereof has been described above, but the present invention is not limited to this embodiment and the modification thereof.

  In other words, it should be considered that the embodiment and its modification disclosed this time are illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  For example, the shape of the electrode body is not limited to the winding type, and may be a shape in which long strip-shaped electrode plates are stacked in a bellows shape by repeating mountain folding and valley folding, as shown in FIG. It does not matter even if it is a shape (laminated type) in which flat plate plates are laminated.

  FIG. 17 is a cross-sectional view of the vicinity of the tab portion 421X, the conductive material 520D, and the negative electrode current collector 130 according to another embodiment. Specifically, FIG. 17 is a cross-sectional view of the energy storage device according to the present embodiment corresponding to the VI-VI line in FIG. 5, and the spacer 140 is not shown in the drawing.

  The electrode body 400X shown in the figure is formed by laminating a plate-like positive electrode 410X, a plate-like negative electrode 420X, and a plate-like separator 430, and a positive-side tab portion (not shown) and a negative-electrode-side tab portion 421X. The positive electrode current collector 120 and the negative electrode current collector 130 are electrically connected.

  In the above-described embodiment including the wound electrode body and the modification thereof, the tab portion is provided at any position in the circumferential direction of the electrode body. That is, in the cross-sectional view, the tab portion is drawn from half of the plurality of layers constituting the electrode body. On the other hand, in the present embodiment, the tab portion 421X is drawn out from all of a plurality of layers constituting the stacked electrode body 400X in a cross-sectional view. Here, each layer is configured by stacking a positive electrode 410X, a negative electrode 420X, and a separator 430X.

  As described above, even in the configuration including the stacked electrode body 400X, the conductive material 520 is disposed in contact with the tab portion 421X, as in the first embodiment, so that the electrode body 400X and the negative electrode current collector are arranged. The electrical resistance between the body 130 can be reduced.

  Further, the positional relationship between the tab portion on the positive electrode side and the tab portion on the negative electrode side is not particularly limited. For example, in the wound electrode body, the tab portions may be arranged on opposite sides in the winding axis direction. In the electrode body of the mold, the electrode bodies may be arranged in different directions as viewed in the stacking direction.

  Further, the conductive material does not have to be disposed in contact with each of the positive electrode tab portion and the negative electrode tab portion, and the conductive material contacts at least one of the positive electrode tab portion and the negative electrode tab portion. What is necessary is just to be arrange | positioned in contact.

  Further, the conductive material disposed in contact with the tab portion is not particularly limited as long as it has conductivity, and may be a metal clip or the like, for example. The conductive material is not limited to an integral member, and may be a plurality of members.

  The number of members constituting each of the positive electrode current collector 120 and the negative electrode current collector 130 is not particularly limited. For example, the positive electrode current collector 120 and the negative electrode current collector 130 may be constituted by one metal member, or may be constituted by a plurality of metal members. It doesn't matter. In addition, each of the positive electrode current collector 120 and the negative electrode current collector 130 only needs to have conductivity, and may not be a member having conductivity and rigidity.

  Moreover, in the said Embodiment 2 and its modification, the 2nd electroconductive part of the tab part was formed with all the metal foils of the laminated body of the metal foil which comprises the said tab part. That is, the second conductive portion is a laminate of metal foil. However, the second conductive portion only needs to be formed of at least one metal foil, and may be formed of only one outermost metal foil, for example. However, from the viewpoint of reducing the electrical resistance between the electrode body and the current collector (positive electrode current collector or negative electrode current collector), the second conductive portion is formed of a laminate of a plurality of metal foils. It is preferable that it is formed by the laminated body of all the metal foils which comprise a tab part especially.

  In addition, in the laminate of metal foils forming the second conductive portion, at least one metal foil constituting the tab portion is folded several times or wound around the first conductive portion many times, etc. It may be formed by.

  In the second embodiment and the modification thereof, the first conductive portion and the second conductive portion of the tab portion are joined together when the tab portion is joined to the current collector. That is, the first conductive portion and the second conductive portion are bonded at the bonding position between the tab portion and the current collector. However, the joining position between the tab portion and the current collector and the joining position between the first conductive portion and the second conductive portion may be different. For example, in the second embodiment, when the second conductive portion protrudes at the center of the first conductive portion, the tab portion and the current collector are joined at the tip of the first conductive portion, and the first conductive portion The second conductive portion may be joined at the center of the first conductive portion.

  Even in such a configuration, since the cross-sectional area of the conductor between the electrode body and the current collector can be increased, the electrical resistance between the electrode body and the current collector can be reduced. In addition, since the first conductive portion and the second conductive portion are joined, a current flows more effectively to the second conductive portion, and the electric resistance between the electrode body and the current collector is reduced. Further reduction can be achieved. However, from the viewpoint of shortening the conductive path between the electrode body and the current collector, the first conductive portion and the second conductive portion are joined together at the joining position of the tab portion and the current collector. It is preferable.

  Moreover, the form constructed | assembled combining the said embodiment and its modification arbitrarily is also contained in the scope of the present invention. Moreover, the structure which combines suitably the partial structure of the said embodiment and its modification may be sufficient.

  Since the electrical resistance between the electrode body and the current collector can be reduced, the present invention can be applied to a power storage element or the like mounted in an automobile or the like that requires high output.

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Container 110 Cover body 111 Main body 120 Positive electrode current collector 121, 122, 131, 131C, 132 Junction part 130, 130A, 130C Negative electrode current collector 140 Spacer 141, 142 Notch 143 Through-hole 150 Safety valve 200 Positive electrode Terminal 300 Negative electrode terminal 400, 400H, 400I, 400X Electrode body 401 Power generation part 410, 410H, 410I, 410X Positive electrode 411, 411H, 421, 421A, 421H, 421I, 421J, 421X Tab part 411a, 411h, 421a, 421h Protruding part 420, 420H, 420I, 420X Negative electrode 430, 430X Separator 441 First conductive portion 442a, 442b, 442j, 442k Second conductive portion 510, 520, 520A, 520C, 520D Conductive material

Claims (8)

An electrical storage element comprising an electrode body and a current collector connected to the electrode body,
The electrode body has a tab portion protruding outward and connected to the current collector,
The power storage element further includes a conductive material disposed in contact with the tab portion. The electricity storage device further includes a container that houses the electrode body and has a safety valve,
The power storage device according to claim 1, wherein the conductive material is disposed at a position different from that between the safety valve and the electrode body. The electric storage element according to claim 1, wherein the conductive material is disposed so as to surround an outer periphery of the tab portion. The electricity storage device according to claim 1, wherein the conductive material is a conductive tape attached to the tab portion. The power storage device according to claim 1, wherein the conductive material is further disposed in contact with the current collector. The tab portion and the conductive material are integrally formed,
The electric storage element according to any one of claims 1 to 5, wherein the conductive material is disposed in contact with the tab portion in a state of being bent with respect to the tab portion. The conductive material includes two conductive portions connected to the tab portion,
The power storage element according to claim 6, wherein the two conductive portions are arranged to face each other with the tab portion interposed therebetween in a state where the two conductive portions are bent with respect to the tab portion. The electricity storage device according to claim 1, wherein the conductive material is joined to the tab portion.

Images