JP2018110083A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable power storage device including a power storage element, and a conductive member for electrically connecting a power storage element and at least one electrical component.SOLUTION: In power storage device 10 including a power storage element 300, and a conductive member 500 for electrically connecting the power storage element 300 and at least one electrical component, i.e., a protection circuit 800, the conductive member 500 has a first conductive member 510 including a first end 511, i.e., the end on the power storage element 300 side, and a second conductive member 520 including a second end 521, i.e., the end on the protection circuit 800 side, and formed of a material different from that of the first conductive member 510, and the junction 580 of the first and second conductive members 510, 520 is arranged at an intermediate part between the first end 511 and second end 521.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power storage device including a power storage element.

  Conventionally, for example, a technique relating to a joint portion between a terminal of a secondary battery and a conductive member has been disclosed (see Patent Document 1). In this secondary battery, a conversion part in which different metals are joined to each other is provided on one of the positive current path member and the negative current path member. The same kind of metal material as that of the conductive member such as a bus bar is exposed on the surface of each joint portion of the positive and negative external terminals.

JP 2012-123946 A

  When a portion (joint portion) where dissimilar metals are joined on the current path is provided as in the conventional secondary battery, the joint portion may generate heat due to a difference in physical properties such as resistance. In this regard, for example, in the above-described conventional secondary battery, the junction between different metals is provided on the electrode terminal fixed to the case of the secondary battery, so the secondary battery receives heat from the junction. Cheap. This is not preferable from the viewpoint of the performance or safety of the secondary battery, for example.

  Further, not only other power storage elements but also electrical parts such as fuses or relays, or electrical circuits including a plurality of electrical parts may be arranged on a current path extending from a power storage element such as a secondary battery. is there. Therefore, there is a possibility that one or more electrical components are deteriorated by the heat of the joint between different metals.

  In view of the above-described conventional problems, the present invention provides a power storage device including a power storage element and a conductive member that electrically connects the power storage element and at least one electrical component, and provides a highly reliable power storage device. For the purpose.

  In order to achieve the above object, a power storage device according to one embodiment of the present invention is a power storage device including a power storage element and a conductive member that electrically connects the power storage element and at least one electrical component, The conductive member is a first conductive member including a first end portion that is an end portion on the power storage element side, and a second conductive member including a second end portion that is an end portion on the at least one electric component side. And a second conductive member formed of a material having a physical property different from that of the first conductive member, and the joining portion of the first conductive member and the second conductive member is the first end and the second end. It is arrange | positioned in the intermediate part between parts.

  According to this configuration, for example, as the material of the first conductive member, a material having a good bondability with the electrode terminal of the power storage element is selected, and as the material of the second conductive member, the resistance is higher than that of the first conductive member. The design for improving the reliability of the power storage device, such as selecting a small material, is easy.

  In addition, it is possible to protect electrical / electronic circuits or electrical components for the purpose of control, monitoring, or device protection from the heat generated at the junction, and the heat generated at the junction is transferred to the storage element. The amount of conduction can be suppressed.

  As described above, the power storage device of this aspect is a power storage device including a power storage element and a conductive member that electrically connects the power storage element and at least one electrical component, and is a highly reliable power storage device.

  In the power storage device according to one embodiment of the present invention, the distance between the joint and the at least one electrical component on the current path in the conductive member is the distance between the joint and the power storage element. Longer than that.

  According to this configuration, at least one electrical component connected to the conductive member can be more accurately protected from the heat generated at the joint.

  Further, in the joint portion of the power storage device according to one embodiment of the present invention, a physical property different from any of the first conductive member and the second conductive member between the first conductive member and the second conductive member. A third conductive member formed of the above material may be interposed.

  According to this configuration, for example, the third conductive member is formed of a material having an ionization tendency between the ionization tendency of the material of the first conductive member and the ionization tendency of the material of the second conductive member. The difference in ionization tendency between the materials in contact with each other can be reduced. As a result, for example, corrosion at the joint is suppressed.

  In the power storage device according to one embodiment of the present invention, the third conductive member may be a plating layer coated on the first conductive member or the second conductive member.

  According to this configuration, for example, since the third conductive member is formed thin, an increase in the thickness of the joint portion by including the third conductive member is suppressed. In addition, since the third conductive member is integrated with the first conductive member or the second conductive member, the work of the third conductive member is performed during the work for forming the joint (welding, caulking, fastening, etc.). The work can be appropriately executed without performing positioning or temporary pressing.

  In the power storage device according to one embodiment of the present invention, the third conductive member may be a plate material.

  According to this configuration, for example, unlike the case where the third conductive member is disposed as a plating layer on the first conductive member or the second conductive member, there arises a problem of peeling off due to vibration during joining. Absent. Further, for example, a plurality of third conductive members can be obtained by cutting one metal plate. This is advantageous, for example, from the viewpoint of unifying or managing the quality of the third conductive member.

  The power storage device according to one embodiment of the present invention further includes a sealing member disposed between the first conductive member and the second conductive member at a position on a side of the joint. Also good.

  According to this configuration, the presence of the sealing member reduces the possibility that outside air or moisture will reach the joint. As a result, for example, corrosion of the joint, which is a part where dissimilar metals are joined, is suppressed.

  In the power storage device according to one embodiment of the present invention, the first conductive member and the second conductive member may be joined by clinch caulking.

  According to this configuration, for example, the first conductive member and the second conductive member can be joined without using other members such as bolts and nuts, or rivets. In addition, since the first conductive member and the second conductive member are mechanically meshed, for example, there is no problem of heat generated during welding.

  ADVANTAGE OF THE INVENTION According to this invention, it is an electrical storage apparatus provided with an electrical storage element and the electrically-conductive member which electrically connects an electrical storage element and at least 1 electrical component, Comprising: A reliable electrical storage apparatus can be provided.

It is a perspective view which shows the external appearance of the electrical storage apparatus which concerns on embodiment. It is a disassembled perspective view which shows each component at the time of decomposing | disassembling the electrical storage apparatus which concerns on embodiment. It is a perspective view of the electrical storage element which concerns on embodiment. It is sectional drawing which shows the structure of the electrically-conductive member which concerns on embodiment. It is a cross-sectional enlarged view which shows the structure of the electrically-conductive member which concerns on the specific example 1 of embodiment. It is a cross-sectional enlarged view which shows the structure of the electrically-conductive member which concerns on the specific example 2 of embodiment. It is a cross-sectional enlarged view which shows the structure of the electrically-conductive member which concerns on the specific example 3 of embodiment.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. The following embodiment shows a comprehensive or specific example. The numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, the steps in the manufacturing method, the order of the steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Absent. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements. In each drawing, dimensions and the like are not strictly illustrated.

  Further, in the following description and drawings, the arrangement direction of a plurality of power storage elements, the facing direction of the long side surface of the container of the power storage elements, or the thickness direction of the container is defined as the X-axis direction. In addition, the direction in which the electrode terminals are arranged in one power storage element or the facing direction of the short side surface of the container of the power storage element is defined as the Y-axis direction. Further, the direction in which the outer body body and the lid of the power storage device are arranged, the direction in which the container body and the container lid of the power storage element are arranged, or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect (orthogonal in this embodiment). Although the case where the Z-axis direction does not become the vertical direction may be considered depending on the usage mode, the Z-axis direction will be described below as the vertical direction for convenience of explanation. In the following description, for example, the X axis direction plus side indicates the arrow direction side of the X axis, and the X axis direction minus side indicates the opposite side to the X axis direction plus side. The same applies to the Y-axis direction and the Z-axis direction.

(Embodiment)
First, a general description of the power storage device 10 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing an external appearance of a power storage device 10 according to an embodiment. FIG. 2 is an exploded perspective view showing each component when the power storage device 10 according to the embodiment is disassembled. In FIG. 2, the current path on the positive electrode side of the power storage element unit 380 is conceptually illustrated by a dotted line, and the current path on the negative electrode side of the power storage element unit 380 is conceptually illustrated by a one-dot chain line.

  The power storage device 10 is a device that can charge electricity from the outside and discharge electricity to the outside. For example, the power storage device 10 is a battery module used for power storage use, power supply use, and the like. Specifically, the power storage device 10 is, for example, an automobile such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), a motorcycle, a watercraft, a snowmobile, an agricultural machine, a construction It is used as a battery for driving a moving body such as a machine or starting an engine.

  As shown in FIGS. 1 and 2, the power storage device 10 includes an exterior body 11 including a lid body 100 and an exterior body body 200, a plurality of power storage elements 300 and a plurality of bus bars 400 housed inside the exterior body 11. It has. It should be noted that other elements such as a bus bar frame may be disposed inside the exterior body 11.

  The exterior body 11 is a rectangular (box-shaped) container (module case) that constitutes the exterior body of the power storage device 10. That is, the exterior body 11 is disposed outside the plurality of power storage elements 300, the bus bar 400, and the like, and the power storage elements 300 are disposed at predetermined positions to protect them from impacts and the like. The exterior body 11 is made of an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polybutylene terephthalate (PBT), or ABS resin. Thus, the exterior body 11 avoids the storage element 300 and the like from coming into contact with an external metal member or the like.

  The lid 100 is a flat rectangular member that closes the opening of the exterior body 200, and is provided with a positive external terminal 110 and a negative external terminal 120. The power storage device 10 charges electricity from the outside via the positive electrode external terminal 110 and the negative electrode external terminal 120, and discharges electricity to the outside. The exterior body 200 is a bottomed rectangular cylindrical housing in which an opening is formed.

  The power storage element 300 is a secondary battery (unit cell) that can charge and discharge electricity, and more specifically, a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. . The power storage element 300 has a flat rectangular parallelepiped shape (square shape), and in this embodiment, eight power storage elements 300 are arranged in the X-axis direction. Note that the shape of the power storage element 300 and the number of the power storage elements 300 arranged are not limited. The storage element 300 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, a capacitor, or a user charging a battery. The battery may be a primary battery that can use the stored electricity without having to perform the operation. A detailed description of the configuration of the storage element 300 will be described later.

  The bus bar 400 is a rectangular plate-like member that is disposed on the plurality of power storage elements 300 and electrically connects the electrode terminals of the plurality of power storage elements 300. In the present embodiment, bus bar 400 is formed of an aluminum alloy.

  In the present embodiment, bus bar 400 includes two power storage elements 300 connected in parallel to form four sets of power storage element groups, and the four sets of power storage element groups are connected in series. When a plurality of power storage elements 300 connected in this manner are used as one power storage element unit 380, positive electrodes of the power storage element units 380 (positive terminals of two power storage elements 300 arranged on the X axis direction plus side (described later) The positive terminal 320)) is electrically connected to the positive external terminal 110. Specifically, in the present embodiment, the positive electrode of power storage element unit 380 is electrically connected to positive external terminal 110 via conductive member 500, protection circuit 800, and the like.

  Further, the negative electrode of the power storage element unit 380 (the negative terminals of the two power storage elements 300 arranged on the negative side in the X-axis direction (a negative electrode terminal 330 described later)) is electrically connected to the negative external terminal 120 via the conductive member 550 and the like. Connected.

  In addition, the connection form of the some electrical storage element 300 is not limited to what is shown in FIG. 2, For example, the different polarity of two adjacent electrical storage elements 300 is connected with a bus bar, and all 8 pieces are connected in series. It may be connected.

  In the present embodiment, conductive member 500 includes a first conductive member 510 and a second conductive member 520. A power storage element 300 (two power storage elements 300 in FIG. 2) is connected to one end of the first conductive member 510, and a protection circuit 800 is connected to one end of the second conductive member 520. Further, the other end of the first conductive member 510 and the other end of the second conductive member 520 are joined. In the present embodiment, first conductive member 510 and second conductive member 520 are joined in the thickness direction.

  The first conductive member 510 and the second conductive member 520 are joined with the third conductive member 600 interposed therebetween. Similarly, in the negative electrode side conductive member 550, the first conductive member 560 and the second conductive member 570 are joined in the plate thickness direction with the third conductive member 600 interposed therebetween.

  The protection circuit 800 includes a fuse, for example, and when a large current exceeding the normal range flows through the protection circuit 800, the fuse is blown to cut off a current path including the protection circuit 800. That is, in the power storage device 10, when an unusual current flows due to a short circuit or the like, discharging from the power storage device 10 and charging to the power storage device 10 are stopped. The protection circuit 800 is an example of “at least one electrical component” electrically connected to the second conductive member 520, but the circuit component such as a fuse included in the protection circuit 800 is “at least one electrical component”. It can also be said.

  The first conductive member 510 (560) and the second conductive member 520 (570) can be joined by various methods such as welding, caulking, and fastening. Details regarding the conductive member 500 having the first conductive member 510 and the second conductive member 520 will be described later with reference to FIGS.

  Next, the structure of the electrical storage element 300 will be described in detail. FIG. 3 is a perspective view of a power storage device 300 according to the embodiment. In FIG. 3, the inside of the electricity storage device 300 is shown through the container 310 of the electricity storage device 300.

  As shown in FIG. 3, the electricity storage device 300 includes a container 310, a positive electrode terminal 320, and a negative electrode terminal 330. In addition, an electrode body 340, a positive electrode current collector 350, and a negative electrode current collector 360 are disposed inside the container 310. In addition, although electrolyte solution (nonaqueous electrolyte) is also enclosed inside the container 310, illustration is abbreviate | omitted. In addition to the above components, a gasket may be disposed between the positive electrode terminal 320, the negative electrode terminal 330, the positive electrode current collector 350, the negative electrode current collector 360, and the container 310, or the electrode body 340 and the container. A spacer may be disposed between the spacer 310 and the substrate 310.

  The container 310 includes a container main body 311 and a container lid 312. Specifically, the container 310 includes a bottom surface portion 315 on the negative side in the Z-axis direction in FIG. 3, a long side surface portion 314 on the side surfaces on both sides in the X-axis direction, a short side surface portion 313 on the side surfaces on both sides in the Y-axis direction, This is a rectangular parallelepiped (square) container having a container lid 312 on the plus side. That is, in the container 310, the bottom surface portion 315, the two long side surface portions 314, and the two short side surface portions 313 constitute a container main body 311 having a rectangular cylindrical shape and a bottom, and the opening of the container main body 311 is made the container lid portion 312. Is configured to close.

  Specifically, the container 310 can seal the inside by accommodating the electrode body 340 and the like inside the container body 311 and then joining the container body 311 and the container lid 312 by welding or the like. It has a structure. The material of the container 310 (the container main body 311 and the container lid 312) is not particularly limited, but is preferably a weldable (joinable) metal such as stainless steel, aluminum, or aluminum alloy.

  The electrode body 340 is a power storage element (power generation element) that can store electricity, and includes a positive electrode plate, a negative electrode plate, and a separator, and the positive electrode plate, the negative electrode plate, and the separator are stacked in the X-axis direction. Yes. Specifically, the electrode body 340 is a wound electrode formed by winding a positive electrode plate, a negative electrode plate, and a separator around a winding axis (virtual axis in the Y-axis direction passing through the center of the electrode body 340). And is electrically connected to the positive electrode current collector 350 and the negative electrode current collector 360.

  The positive electrode plate is an electrode plate in which a positive electrode mixture layer is formed on the surface of a positive electrode base material layer which is a long strip-shaped metal foil made of aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode mixture 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. The separator is a microporous sheet made of resin. In addition, as a positive electrode active material and a negative electrode active material used for a positive electrode compound material layer and a negative electrode compound material layer, if it is an active material which can occlude-release lithium ion, a well-known material can be used suitably. As for the separator, a known material can be appropriately used as long as it does not impair the performance of the electricity storage element 300.

  More specifically, in the electrode body 340, a positive electrode plate and a negative electrode plate are wound while being shifted from each other in the direction of the winding axis (Y-axis direction) via a separator. And the positive electrode plate and the negative electrode plate have a composite material layer non-formation part which is a part where the composite material layer is not formed and the base material layer is exposed at the end of each shifted direction. Specifically, the electrode body 340 has a positive electrode side end portion 341 in which a mixture layer non-forming portion of the positive electrode plate is laminated at one end in the winding axis direction (end portion on the Y axis direction plus side). Yes. Similarly, the electrode body 340 has a negative electrode side end portion 342 in which a mixture layer non-forming portion of the negative electrode plate is laminated on the other end in the winding axis direction (end portion on the negative side in the Y axis direction). ing.

  The positive electrode current collector 350 is disposed between the positive electrode plate of the electrode body 340 and the side wall of the container 310, and has electrical conductivity and rigidity that are electrically connected to the positive electrode terminal 320 and the positive electrode plate of the electrode body 340. It is a member. The negative electrode current collector 360 is disposed between the negative electrode plate of the electrode body 340 and the side wall of the container 310, and has electrical conductivity and rigidity electrically connected to the negative electrode terminal 330 and the negative electrode plate of the electrode body 340. It is a member provided with. Specifically, the positive electrode current collector 350 is joined to the positive electrode side end 341 of the electrode body 340 by welding or the like, and the negative electrode current collector 360 is joined to the negative electrode side end 342 of the electrode body 340 by welding or the like. ing. The positive electrode current collector 350 is formed of aluminum or an aluminum alloy as in the case of the positive electrode base material layer of the positive electrode plate, and the negative electrode current collector 360 is similar to the negative electrode base material layer of the negative electrode plate such as copper or copper alloy. It is formed with.

  The positive electrode terminal 320 is an electrode terminal electrically connected to the positive electrode plate of the electrode body 340 via the positive electrode current collector 350, and the negative electrode terminal 330 is connected to the electrode body 340 via the negative electrode current collector 360. The electrode terminal is electrically connected to the negative electrode plate. Specifically, for example, the positive electrode terminal 320 is caulked in a state in which a rivet portion extending from the positive electrode terminal 320 penetrates the container lid portion 312 and the positive electrode current collector 350, so that the positive electrode current collector 350 and the machine Connected electrically and electrically. Similarly, the negative electrode terminal 330 is mechanically and electrically connected to the negative electrode current collector 360 by caulking the rivet portion extending from the negative electrode terminal 330 through the container lid 312 and the negative electrode current collector 360. Connected.

  In other words, the positive electrode terminal 320 and the negative electrode terminal 330 lead the electricity stored in the electrode body 340 to the external space of the power storage element 300, and in order to store the electricity in the electrode body 340, It is an electrode terminal made of metal for introducing. In addition, as a material of the positive electrode terminal 320 and the negative electrode terminal 330, aluminum or an aluminum alloy is adopted. In the present embodiment, the positive terminal 320 and the negative terminal 330 are made of aluminum.

  Here, when the positive electrode terminal 320 and the negative electrode terminal 330 are made of aluminum, the conductor welded to at least one of the positive electrode terminal 320 and the negative electrode terminal 330 such as the bus bar 400 is also formed of aluminum or an aluminum alloy.

  Specifically, in this embodiment, bus bar 400 and first conductive members 510 and 560 that are welded to at least one of positive electrode terminal 320 and negative electrode terminal 330 are formed of aluminum. That is, the material of the conductor connected to the positive electrode terminal 320 and the negative electrode terminal 330 is the same type of metal as the electrode terminals (aluminum in the present embodiment) in consideration of the reliability of the welded portion with these electrode terminals. It is advantageous.

  However, on the other hand, from the viewpoint of suppressing electrical resistance, it is preferable to employ, for example, copper as the conductor material. That is, since the magnitude of the electrical resistance in the current path in the power storage device 10 leads to problems such as increased energy loss and heat generation, the electrical resistance is preferably small.

  Therefore, in the present embodiment, among the conductive members 500 connected to the positive terminal 320, aluminum is adopted as the material of the first conductive member 510 connected to the positive terminal 320, and the second connected to the protection circuit 800. Copper is employed as the material of the conductive member 520. In addition, among the conductive members 550 connected to the negative electrode terminal 330, aluminum is adopted as the material of the first conductive member 560 connected to the negative electrode terminal 330, and the current between the first conductive member 560 and the negative electrode external terminal 120. Copper is employed as the material of the second conductive member 570 that forms part of the path.

  Hereinafter, details and specific examples of the configuration of the conductive member 500 disposed on the positive electrode side of the power storage element unit 380 will be described with reference to FIGS. 4 to 7. Note that the basic configuration of the conductive member 550 disposed on the negative electrode side of the power storage element unit 380 is the same as that of the conductive member 500, and thus the description of the conductive member 550 is omitted.

  FIG. 4 is a cross-sectional view showing a configuration of the conductive member 500 according to the embodiment. In FIG. 4, a cross section parallel to the XZ plane of the conductive member 500 is illustrated, and side surfaces of the power storage element 300 and the protection circuit 800 are illustrated. In addition, various methods such as fastening, caulking, and welding are used for joining the conductive member 500 to the storage element 300 and the protection circuit 800. In FIG. (Not shown). In the present embodiment, positive electrode terminals 320 (see, for example, FIG. 2) of two power storage elements 300 that constitute the positive electrode of power storage element unit 380 are joined to first conductive member 510 by, for example, laser welding. The However, for clarity of the configuration of the conductive member 500, the illustration and description of the inner storage element 300 (the negative side in the X-axis direction) of the two storage elements 300 are omitted.

  As shown in FIG. 4, power storage device 10 according to the present embodiment includes power storage element 300, a conductive member that electrically connects power storage element 300 and at least one electrical component (protection circuit 800 in the present embodiment). 500. The conductive member 500 includes a first conductive member 510 including a first end portion 511 that is an end portion on the power storage element 300 side, and a second conductive member 520 including a second end portion 521 that is an end portion on the protection circuit 800 side. Have The second conductive member 520 is formed of a material having physical properties different from those of the first conductive member 510. The joint portion 580 between the first conductive member 510 and the second conductive member 520 is disposed at an intermediate portion between the first end portion 511 and the second end portion 521.

  According to this configuration, a material having good bondability with the positive electrode terminal 320 of the electricity storage element 300 is selected as the material of the first conductive member 510 and the material of the second conductive member 520 is selected from the first conductive member 510. Even materials with low resistance can be selected. Specifically, as described above, the first conductive member 510 is formed of aluminum, and the second conductive member 520 is formed of copper. Thereby, the reliability about the welding part of the electroconductive member 500 and the positive electrode terminal 320 made from aluminum is ensured, and the electrical resistance as the electroconductive member 500 whole is suppressed. Thereby, the reliability of the power storage device 10 is improved.

  Note that an aluminum alloy may be employed as the material of the first conductive member 510, and a copper alloy may be employed as the material of the second conductive member 520. Even in this case, it is possible to obtain the effects of ensuring the reliability of the welded portion between the conductive member 500 and the positive electrode terminal 320 made of aluminum, and suppressing the electrical resistance of the conductive member 500 as a whole.

  In addition, the joint portion 580 of the first conductive member 510 and the second conductive member 520 is a portion where dissimilar metals having different electrical resistances are joined to each other, so that heat is easily generated. However, the joint 580 is disposed apart from each of the power storage element 300 and the protection circuit 800.

  Specifically, the first conductive member 510 has a first end 511 joined to the positive electrode terminal 320 of the electricity storage element 300 by laser welding or the like, and extends from the first end 511. The extending portion 512 is provided. The joint portion 580 is provided at the end of the first extending portion 512 on the protection circuit 800 side (meaning the side near the protection circuit 800 in the current path, the same applies hereinafter).

  The second conductive member 520 has a second end 521 joined to a lead plate 820 provided in the circuit body 810 of the protection circuit 800, and extends from the second end 521. Two extending portions 522 are provided. The joint portion 580 is provided at the end of the second extending portion 522 on the power storage element 300 side.

  That is, the junction 580 is far from the end of the first conductive member 510 far from the power storage element 300 (the end of the first extending portion 512) and the protection circuit 800 of the second conductive member 520 in the current path. This is a portion where the side end (the end of the second extending portion 522) is joined. Note that the current path in the conductive member 500 is a direction connecting the first end 511 and the second end 512, and the plate thickness of the conductive member 510 and the second conductive member 520, both of which are plate-like members. It is formed in a direction orthogonal to the direction.

  Therefore, the conduction amount of heat generated in the joint portion 580 to the power storage element 300 can be suppressed, and one or more electrical components (the protection circuit 800 in this embodiment mode) can be prevented from the heat generated in the joint portion 580. ) Can be protected. Therefore, even if the junction 580 generates heat, the occurrence of problems such as thermal runaway due to the heat is suppressed. Thus, the power storage device 10 according to the present embodiment is a highly reliable power storage device 10.

  In the present embodiment, on the current path in the conductive member 500, the distance L1 between the junction 580 and at least one electrical component (the protection circuit 800 in this embodiment) is equal to the junction 580 and the power storage. It is longer than the distance L <b> 2 between the element 300.

  According to this configuration, the protection circuit 800 connected to the conductive member 500 can be more accurately protected from the heat generated at the joint 580.

  Here, in the joint portion 580 according to the present embodiment, a material having a physical property different from any of the first conductive member 510 and the second conductive member 520 is provided between the first conductive member 510 and the second conductive member 520. The formed third conductive member 600 is interposed. That is, the first conductive member 510 and the second conductive member 520 are joined via the third conductive member 600 as shown in FIG.

  In the present embodiment, nickel is adopted as the material of the third conductive member 600. Nickel has a lower ionization tendency than aluminum, which is the material of the first conductive member 510, and has a higher ionization tendency than copper, which is the material of the second conductive member 520.

  Accordingly, the difference in ionization tendency between different kinds of metals (between aluminum and nickel, between nickel and copper) is greater than in the case where the first conductive member 510 and the second conductive member 520 are in direct contact with each other at the joint 580. Get smaller.

  As a result, in the joint portion 580, corrosion (oxidation) due to a large ionization tendency between different metals in contact is suppressed. In other words, by interposing the third conductive member 600 between the first conductive member 510 and the second conductive member 520 in the joint portion 580, deterioration of the quality or reliability of the power storage device 10 is suppressed.

  Further, the third conductive member 600 made of nickel is easily welded to each of the first conductive member 510 made of aluminum and the second conductive member 520 made of copper. Therefore, the bonding strength of the bonding portion 580c can be improved by interposing the third conductive member 600 between the first conductive member 510 and the second conductive member 520.

  The material of the third conductive member 600 may be a nickel alloy in which, for example, aluminum, iron, copper, or the like is added to nickel.

  In addition to nickel, zinc, chromium, and the like are used as the material of the third conductive member 600 and have a lower ionization tendency than aluminum and a higher ionization tendency than copper.

  The third conductive member 600 may be formed by stacking a plurality of members. For example, the third conductive member 600 may be formed by laminating two kinds of materials such as nickel and zinc, or three or more kinds of materials such as zinc and chromium may be laminated in addition to nickel. The third conductive member 600 may be formed. For example, in the third conductive member 600, a plurality of members are in the order of ionization tendency (descending order) from the first conductive member 510 side formed of aluminum toward the second conductive member 520 side formed of copper. They may be arranged side by side. Thus, by interposing the third conductive member 600 composed of a plurality of layers between the first conductive member 510 and the second conductive member 520, the difference in ionization tendency between adjacent dissimilar metals becomes smaller, Corrosion (oxidation) is suppressed more effectively.

  In the present embodiment, the third conductive member 600 is a plate material, for example, as shown in FIG. Thereby, for example, unlike the case where the third conductive member 600 is arranged as a plating layer on the first conductive member 510 or the second conductive member 520, there arises a problem of peeling off due to vibration during joining. Absent. Further, for example, a plurality of third conductive members 600 can be obtained by cutting one metal plate. This is advantageous from the viewpoint of unifying or managing the quality of the third conductive member 600, for example.

  Here, in the present embodiment, each of the first conductive member 510 and the second conductive member 520 is a plate-like member, and in the joint portion 580, the first extending portion 512 of the first conductive member 510, The second extending portion 522 of the second conductive member 520 is joined in a state of being overlapped in the plate thickness direction. Moreover, as the joining method, various methods can be adopted as described above. Therefore, a specific example of the joining method (joining mode) of the first conductive member 510 and the second conductive member 520 according to the embodiment will be described with reference to FIGS. In addition, the conductive members 500a to 500c shown in the following specific examples 1 to 3 are members having the same basic configuration as the conductive member 500 according to the above-described embodiment and having different bonding modes in the bonding portion. is there.

(Specific example 1)
FIG. 5 is an enlarged cross-sectional view illustrating a configuration of the conductive member 500a according to the first specific example of the embodiment. The joining part 580a of the conductive member 500a shown in FIG. 5 is a fastener in a state where the first extending part 512 of the first conductive member 510 and the second extending part 522 of the second conductive member 520 are overlapped. It is formed by being fastened by 900.

  The fastener 900 has a pair of bolts 910 and nuts 920. For example, as shown in FIG. 5, the shaft portion of the bolt 910 includes the first conductive member 510, the third conductive member 600, and the second conductive member 520. The nut 920 that is screwed into the shaft portion of the bolt 910 is tightened in the penetrated state. Accordingly, the first conductive member 510 and the second conductive member 520 are fastened with the third conductive member 600 interposed therebetween.

  Thus, by using the fastener 900 for joining the first conductive member 510 and the second conductive member 520, the first conductive member 510 and the second conductive member 520 can be firmly joined with a simple configuration.

  Here, since the fastening force by the bolt 910 and the nut 920 does not directly act on the outer peripheral portion (in FIG. 5, the upper end portion and the lower end portion of the joint portion 580a) of the joint portion 580a, There may be a gap between the conductive members 520. For example, when moisture enters the gap, corrosion of the joint 580 may occur. However, in this specific example, the third conductive member 600 made of nickel is interposed between the first conductive member 510 and the second conductive member 520, and between the materials in contact at the joint 580a. The difference in ionization tendency is relatively small. Thereby, generation | occurrence | production of the corrosion in the junction part 580a is suppressed.

  For example, a rivet may be employed as the fastener 900 for fastening the first conductive member 510 and the second conductive member 520 instead of the bolt 910 and the nut 920. Further, the first conductive member 510 and the second conductive member 520 may be fastened by a plurality of fasteners 900.

(Specific example 2)
FIG. 6 is an enlarged cross-sectional view illustrating a configuration of a conductive member 500b according to a specific example 2 of the embodiment. The joining part 580b of the conductive member 500b shown in FIG. 6 is a state in which the first extending part 512 of the first conductive member 510 and the second extending part 522 of the second conductive member 520 are overlapped, for example, a laser. It is formed by welding by welding.

  In this specific example, the first extending portion 512 is formed with a protruding portion 512a that protrudes toward the second extending portion 522, and the tip surface of the protruding portion 512a and the second extending portion of the second conductive member 520 are formed. The installation part 522 is joined.

  Further, in this specific example, a sealing member 700 disposed between the first conductive member 510 and the second conductive member 520 is provided at a position on the side of the joint portion 580b. The sealing member 700 is made of a material having elasticity and relatively high heat resistance, such as silicone rubber or ethylene / propylene / diene rubber (EPDM).

  By arranging the sealing member 700 in this way, for example, the possibility that outside air or moisture will reach the joint 580b from the outside is reduced. As a result, for example, corrosion of the joint 580b, which is a part where dissimilar metals are joined, is suppressed.

  In this specific example, the sealing member 700 is formed in an annular shape (when viewed from the X-axis direction), and is disposed so as to surround the joint portion 580b. Thereby, sealing of the boundary between the members (between the first conductive member 510 and the second conductive member 520) in the joint portion 580b is further ensured. That is, the joint portion 580 b is placed in a sealed space formed by the sealing member 700. Therefore, the possibility that the joint portion 580b is corroded is further reduced.

  In addition, the junction part 580b which has a structure shown in FIG. 6 is formed by the following processes, for example. First, the annular sealing member 700 is disposed on the convex portion 512a, and one of the first conductive member 510 and the second conductive member 520 is pushed to the other side. Thereby, the front end surface of the convex portion 512a is pressed against the second extending portion 522 of the second conductive member 520, and the sealing member 700 is in close contact with each of the first conductive member 510 and the second conductive member 520. . Furthermore, while maintaining that state, for example, the laser beam is irradiated from the back side (X-axis direction plus side) of the convex portion 512a, whereby the convex portion 512a and the second extending portion 522 are welded. As a result, the joint portion 580b surrounded by the sealing member 700 is formed.

  Note that a third conductive member made of nickel, for example, may be disposed between the first conductive member 510 and the second conductive member 520 in the joint portion 580b. Even in this case, the first conductive member 510 and the second conductive member 520 are in contact with each other because the third conductive member is present in a portion where the first conductive member 510 and the second conductive member 520 are in contact with each other. The difference in ionization tendency between materials can be reduced. As a result, for example, corrosion at the joint 580b is suppressed. In addition, the presence of the third conductive member formed of nickel that is easily welded to each of the first conductive member 510 and the second conductive member 520 can improve the joint strength of the joint portion 580b.

(Specific example 3)
FIG. 7 is an enlarged cross-sectional view illustrating a configuration of a conductive member 500c according to Specific Example 3 of the embodiment. 7 is caulked in a state in which the first extending portion 512 of the first conductive member 510 and the second extending portion 522 of the second conductive member 520 are overlapped. It is formed by that.

  In this specific example, the first conductive member 510 and the second conductive member 520 are joined by clinch caulking. More specifically, the first extending portion 512 and the second extending portion 522 that are both flat are caulked in a state where they are overlapped, thereby forming a convex portion 512b on the first extending portion 512, and In the second extending portion 522, a concave portion 522a in which the convex portion 512b is press-fitted is formed.

  That is, in this specific example, the first conductive member 510 and the second conductive member 520 are joined without using other members such as bolts and nuts, or rivets, for example. Therefore, an increase in the number of parts necessary for manufacturing power storage device 10 is suppressed. Further, since the first conductive member 510 and the second conductive member 520 are mechanically fitted, there is no problem of heat generated during welding such as laser welding.

  In this specific example, the third conductive member 610 is interposed between the first conductive member 510 and the second conductive member 520, and the third conductive member 610 is a plating layer coated on the second conductive member 520. It is. For example, in the second conductive member 520, nickel plating is applied to at least a clinched area of the surface facing the first conductive member 510, and a nickel plating layer formed thereby is disposed as the third conductive member 610. Has been.

  According to this configuration, for example, since the third conductive member 610 is formed thin, an increase in thickness due to the joint portion 580c including the third conductive member 610 is suppressed. Further, since the third conductive member 610 is integrated with, for example, the second conductive member 520, the positioning of the third conductive member 610 is performed during the work for forming the joint portion 580c (clinch caulking in this specific example). Or the said operation | work can be performed appropriately, without performing temporary pressing.

  The third conductive member 610 that is a plating layer may be formed on the first conductive member 510. Further, the first conductive member 510 and the second conductive member 520 may be joined by clinch caulking without the third conductive member 610 interposed between the first conductive member 510 and the second conductive member 520.

  When the first conductive member 510 and the second conductive member 520 are joined by clinch caulking, the third conductive member 600 (for example, FIG. 2), which is a plate material, is used instead of the third conductive member 610 formed as a plating layer. May be disposed between the first conductive member 510 and the second conductive member 520.

  For example, as shown in FIG. 5, when the first conductive member 510 and the second conductive member 520 are fastened by a bolt 910 and a nut 920, the first conductive member 510 and the second conductive member 520 are A plating layer coated on the one conductive member 510 or the second conductive member 520 may be disposed as the third conductive member.

  For example, as shown in FIG. 6, when the first conductive member 510 and the second conductive member 520 are joined by welding, the first conductive member 510 is interposed between the first conductive member 510 and the second conductive member 520. Alternatively, a plating layer coated on the second conductive member 520 may be disposed as the third conductive member.

(Other embodiments)
Heretofore, the power storage device according to the present invention has been described based on the embodiments and specific examples thereof. However, the present invention is not limited to the above embodiment and specific examples thereof. 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 embodiments or specific examples thereof, or forms constructed by combining a plurality of the above-described constituent elements. Included within the scope of the invention.

  For example, there is no particular limitation on the type of at least one electrical component that is electrically connected to the conductive member 500. A control circuit that controls charging and discharging of the power storage device 10, a voltage measurement circuit that measures the voltage of the plurality of power storage elements 300, or a thermistor for measuring the temperature of the power storage elements 300, etc. The power storage device 10 may be provided as at least one electrical component connected to the. In addition, at least one electrical component electrically connected to the conductive member 500 may be disposed outside the power storage device 10. In any case, since at least one electric component is disposed at a position separated from the joint portion 580 of the conductive member 500, it is difficult to be affected by the heat generated by the joint portion 580.

  In addition, the conductive member 500 is a member that forms a current path between at least one power storage element 300 and at least one electrical component, and the first conductive member 510, the second conductive member 520, and the third conductive member 600. You may have members other than.

  For example, a conductive member (fourth conductive member) separate from the second conductive member 520 may be disposed between the second conductive member 520 and at least one electrical component (for example, the protection circuit 800). In other words, each of the first conductive member 510 and the second conductive member 520 may be composed of a plurality of separate conductive members. In any case, the joint portion 580 is provided in the intermediate portion between the first end portion 511 and the second end portion 521 (see, for example, FIG. 4), so that the joint portion 580 is connected to the power storage element 300 and It can be spaced from at least one electrical component.

  Further, the shapes and sizes of the first conductive member 510 and the second conductive member 520 shown in FIGS. 2 and 4 are examples, and these shapes and sizes are, for example, the size of the exterior body 11 and the exterior body 11. It may be appropriately determined according to the position of other elements such as the protection circuit 800 to be accommodated.

  The features of specific examples 1 to 3 (joined portions 580a, 580b, and 580c) of the joined portion shown in FIGS. 5 to 7 may be combined. For example, the sealing member 700 illustrated in FIG. 6 may be disposed so as to surround the convex portion 512b of the first conductive member 510 illustrated in FIG. In this case, the space in which the joint portion 580c formed by clinch caulking is disposed is sealed by the sealing member 700, and thereby the corrosion of the joint portion 580c is more reliably suppressed.

  Also. For example, clinch caulking may be performed on the inner side (the recessed portion) of the convex portion 512a of the first conductive member 510 shown in FIG. Even in this case, since the space in which the joint portion 580b is disposed is sealed by the sealing member 700, corrosion of the joint portion 580b is more reliably suppressed.

  Further, the electrode body 340 included in the power storage element 300 is formed by vertically winding a positive electrode plate, a negative electrode plate, and a separator (winding with a winding shaft parallel to the Y-axis direction in FIG. 3). It was assumed that it had a winding shape. However, the electrode body 340 has a horizontal winding shape formed by winding a positive electrode plate, a negative electrode plate, and a separator in the horizontal direction (winding with a winding axis parallel to the Z-axis direction). Alternatively, it may be a laminated shape in which flat plate plates are laminated.

  Further, the present invention can be realized not only as such a power storage device 10 but also as a conductive member or the like included in the power storage device 10.

  The present invention can be applied to a power storage device including a power storage element such as a lithium ion secondary battery.

DESCRIPTION OF SYMBOLS 10 Power storage device 300 Power storage element 500, 500a, 500b, 500c, 550 Conductive member 510, 560 First conductive member 511 First end portion 512 First extending portion 520, 570 Second conductive member 521 Second end portion 522 Second Extension portion 580, 580a, 580b, 580c Joint portion 600, 610 Third conductive member 700 Sealing member 800 Protection circuit

Claims (7)

A power storage device comprising: a power storage element; and a conductive member that electrically connects the power storage element and at least one electrical component,
The conductive member is a first conductive member including a first end portion that is an end portion on the power storage element side, and a second conductive member including a second end portion that is an end portion on the at least one electrical component side. And a second conductive member formed of a material having different physical properties from the first conductive member,
The joint portion of the first conductive member and the second conductive member is disposed at an intermediate portion between the first end portion and the second end portion.
Power storage device. On the current path in the conductive member, a distance between the junction and the at least one electrical component is longer than a distance between the junction and the power storage element.
The power storage device according to claim 1. In the joint portion, a third conductive member formed of a material having physical properties different from both the first conductive member and the second conductive member is interposed between the first conductive member and the second conductive member. doing,
The power storage device according to claim 1 or 2. The third conductive member is a plating layer coated on the first conductive member or the second conductive member.
The power storage device according to claim 3. The third conductive member is a plate material.
The power storage device according to claim 3. Furthermore, a sealing member disposed between the first conductive member and the second conductive member at a side position of the joint portion is provided.
The electrical storage apparatus as described in any one of Claims 1-5. The first conductive member and the second conductive member are joined by clinch caulking,
The electrical storage apparatus as described in any one of Claims 1-6.

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