JP2019121566A - Power storage element - Google Patents

Abstract

To provide a power storage element capable of preventing an external terminal, for connection with a collector plate, from cracking without performing heating treatment, and capable of reducing electrical resistance between the external terminal and the power storage element.SOLUTION: The shaft of an external terminal has an enlarged diameter part 43 at the tip penetrating the open hole 33 of a collector plate 30. The enlarged diameter part 43 has a notch 44 in the radial direction. The first half part 43A of the enlarged diameter part 43 contacting the connection 32 of the collector plate 30 connected with a power storage element has a larger connection surface area facing the relay part 31 of the collector plate 30, than a second half part 43B separated from the connection 32 of the collector plate 30.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a storage element.

  BACKGROUND Conventionally, storage elements such as batteries have been known (see Patent Documents 1 and 2 below). Patent Document 1 discloses an electrode terminal having the following features in a sealed battery in which a hollow rivet-like electrode terminal is fixed to the upper lid of a battery case via a sealing packing (the same document, utility model registration) See the claims).

  The electrode terminal of Patent Document 1 integrally includes a flat head on a flat disk facing the upper lid upper surface and a hollow shaft portion. On the back surface of the flat head, an annular protrusion is integrally formed to be in pressure contact with the upper surface of the packing. On the tip end side of the hollow shaft portion, a plurality of caulking open legs divided by the slits are formed. The open leg portion is formed thinner than the shaft portion, and is opened at a fulcrum portion at the boundary with the shaft portion to fix the electrode terminal.

  According to this configuration, the open leg can be flatly bent approximately 90 ° and the cross leg can be opened, whereby the packing can be tightened from above and below between the flat head and the open leg. Therefore, there is no need to squeeze the end of the hollow shaft with a caulking tool with a strong pressing force, and the work of fixing the electrode terminal is simplified.

  Patent Document 2 discloses a battery provided with a battery can, an electrode group, a lid, an insulating plate, a washer, an electrode tab, an insulating gasket, and an output terminal. See). The electrode assembly is housed in a battery can and includes a positive electrode and a negative electrode. The lid closes the opening of the battery can and has a through hole.

  The insulating plate is disposed on one surface of the lid and has a shaft through hole provided to communicate with the through hole of the lid. The washer is disposed on the insulating plate and provided in communication with the shaft through hole of the insulating plate. One end of the electrode tab is electrically connected to the positive electrode or the negative electrode of the electrode group, and the other end is welded to the washer.

  The insulating gasket includes a flange portion, a cylindrical shaft portion, and a shaft insertion hole. The flange portion is disposed on the other side of the lid and has a recess. The cylindrical shaft portion extends from the flange portion and is inserted into the through hole of the lid. The shaft insertion hole is opened in the flange so as to communicate with the hollow in the cylindrical shaft.

  The output terminal has a head and a shaft. The head is disposed within the recess of the flange portion of the insulating gasket. The shaft extends from the head and is inserted into the shaft insertion hole and cylindrical shaft of the insulating gasket and crimped and fixed to the through hole of the lid, the shaft through hole of the insulating plate and the shaft through hole of the washer ing.

Japanese Utility Model Application Publication No. 4-74854 JP, 2009-76394, A

  In the electrode terminal described in Patent Document 1, there is no need to squeeze the tip of the hollow shaft with a caulking tool, and while the work of fixing the electrode terminal is easy, a large gap is formed between the opening legs. . As a result, the current path between the flat terminal and the metal flat O-ring connected to the open leg of the electrode terminal can not be sufficiently secured, which may increase the electrical resistance between the electrode terminal and the storage element.

  On the other hand, in the battery described in Patent Document 2, the electrical resistance between the output terminal and the washer is reduced by forming the maximum extension in the shaft of the output terminal by caulking on the washer, and the output terminal The electrical resistance between the and the electrode group can be reduced. On the other hand, it is necessary to squeeze the shaft portion of the output terminal with a caulking tool, and there is a possibility that a crack may occur in the maximum expansion portion of the shaft portion due to work hardening and ductility reduction. When the heat treatment of the output terminal is performed to prevent such a crack, the manufacturing cost is increased.

  Therefore, it is possible to provide a storage element capable of preventing a crack of an external terminal connected to a current collector without heat treatment and reducing the electrical resistance between the external terminal and the storage element.

  One aspect of the present invention is a container, a storage element housed in the container, a current collector plate connected to the storage element and housed in the container, and a current collector plate connected to the outer surface of the container. A storage element having an external terminal disposed, wherein the external terminal includes a terminal portion disposed on the outer surface of the container, and a shaft portion extending from the terminal portion and penetrating the container The current collector plate is a relay portion extending in a direction orthogonal to the central axis of the shaft portion, and a connection portion provided at one end in the extension direction of the relay portion and connected to the electric storage element; A through hole provided on the other end side in the extending direction of the relay portion than the connection portion, and the shaft portion is formed at an end portion penetrating the through hole from an inner diameter of the through hole Also has an enlarged diameter portion that is enlarged and connected to the relay portion, and the enlarged diameter portion is a notch that is cut out in the radial direction of the shaft portion. Of the two halves separated by the center axis of the shaft and the center line orthogonal to the extension direction of the relay, the first half adjacent to the connection is separated from the connection The storage element is characterized in that the area of the connection surface facing the relay portion is larger than the second half portion.

  According to the above aspect, the distal end portion of the shaft portion of the external terminal penetrated through the through hole of the relay portion of the current collector plate is plastically deformed to expand the diameter to form the enlarged diameter portion, the external terminal and the current collector plate At the time of connecting, the plastic deformation of the tip of the shaft is suppressed by the notch. As a result, in the enlarged diameter portion of the external terminal, work hardening and ductility reduction are suppressed, and cracking can be prevented without heat treatment.

  In the storage element of the above aspect, the current flows from the storage element to the connection portion of the current collector plate, flows from the connection portion to the relay portion of the current collector plate, flows from the relay portion to the enlarged diameter portion of the external terminal, and from the enlarged diameter portion It flows to the shaft of the external terminal and flows from the shaft to the terminal of the external terminal. In addition, current flows from the terminal of the external terminal to the shaft, flows from the shaft to the enlarged diameter, flows from the enlarged diameter to the relay of the current collector plate, flows from the relay to the connection, and stores electricity from the connection. Flow to the element.

  That is, the first half of the enlarged diameter portion close to the connection portion of the current collector plate is a part of the main current path between the external terminal and the storage element, and the current density is higher than that of the second half. . On the other hand, the second half of the enlarged diameter portion separated from the connection portion of the current collector plate deviates from the main current path between the external terminal and the storage element, and has a lower current density than the first half. Further, the first half portion and the second half portion of the enlarged diameter portion are electrically connected to the relay portion of the current collector plate via the connection surface facing the relay portion of the current collector plate.

  Therefore, the area of the connection surface of the first half where the current density is relatively high between the first half and the second half of the enlarged diameter part is the diameter enlarged part where the current density is relatively low. By making the second half portion larger than the connection surface of the second half portion, it is possible to suppress an increase in the electrical resistance between the external terminal and the storage element, and to reduce the electrical resistance. Therefore, according to the above aspect of the present invention, cracking of the external terminal connected to the current collector plate can be prevented without heat treatment, and the electrical resistance between the external terminal and the storage element can be reduced. A storage element that can be provided can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS The external appearance perspective view of the electrical storage element which concerns on Embodiment 1 of this invention. The disassembled perspective view of the electrical storage element shown in FIG. The perspective view which shows the state which expand | deployed a part of electrical storage element of FIG. The disassembled perspective view which expanded the vicinity of the external terminal of FIG. 2, and a current collection board. The expanded sectional view of the vicinity of the external terminal in the crimping process of the electrical storage element shown in FIG. The typical top view of the enlarged diameter part formed of the crimping process shown in FIG. FIG. 2 is an enlarged front view showing an example of a current path in the storage element of FIG. 1; The typical top view of the enlarged diameter part of the electrical storage element which concerns on Embodiment 2 of this invention. FIG. 9 is a distribution diagram of current density in the vicinity of the enlarged diameter portion shown in FIG. 8. The distribution map of the current density of the vicinity of the enlarged diameter part of the electrical storage element which concerns on a comparison form. The graph which shows the resistance rise rate of the electrical storage element of Embodiment 2 and a comparison form. The typical top view of the enlarged diameter part of the electrical storage element which concerns on Embodiment 3 of this invention. The typical top view of the enlarged diameter part of the electrical storage element which concerns on Embodiment 4 of this invention. The typical top view of the enlarged diameter part of the electrical storage element which concerns on Embodiment 5 of this invention.

  Hereinafter, embodiments of a storage element according to the present invention will be described with reference to the drawings.

Embodiment 1
FIG. 1 is an external perspective view of a storage element 100 according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of storage element 100 shown in FIG. The storage element 100 according to the present embodiment is, for example, a flat rectangular lithium ion secondary battery for in-vehicle use. Storage element 100 is mounted, for example, on a vehicle such as an electric vehicle or a hybrid vehicle, supplies power to a device that consumes power such as a motor, and stores power supplied from a device that generates power such as a generator.

  The storage element 100 mainly includes a container 10, a storage element 20 housed in the container 10, a current collector plate 30 connected to the storage element 20 and housed in the container 10, and the current collector plate 30. And an external terminal 40 connected and disposed on the outer surface of the container 10. Further, in the example shown in FIGS. 1 and 2, the storage element 100 includes an insulation sheet 50 covering the storage element 20 and the current collector plate 30, and an insulation plate 60 disposed between the container 10 and the current collector plate 30. And a gasket 70 disposed between the container 10 and the external terminal 40.

  The container 10 is made of, for example, aluminum or an aluminum alloy as a raw material and formed in a thin rectangular solid shape, and has a wide side 10w of the largest area facing the thickness direction of the container 10 and a narrow side of the smallest area along the thickness direction of the container 10 10 n and upper and lower upper and lower surfaces 10 t and 10 b in the height direction of the container 10. The shape of the container 10 of the storage element 100 is not limited to a square, and any shape such as a cylindrical shape can be adopted.

  The container 10 includes, for example, a battery can 11 having an opening 11a at one end, and a battery lid 12 for sealing the opening 11a of the battery can 11. The battery can 11 is, for example, a flat box-shaped member which is provided in a bottomed rectangular cylinder whose upper end is opened and which has a substantially rectangular opening 11a at its upper end. The battery cover 12 is, for example, a substantially rectangular elongated plate-like member whose longitudinal direction is the width direction of the container 10.

  The battery cover 12 has, for example, through holes 12a at both end portions in the longitudinal direction, and a gas discharge valve 12b at the central portion in the longitudinal direction, and the injection plug 12c is disposed between the gas discharge valve 12b and the through hole 12a. The liquid injection port 12 d is sealed by the The gas discharge valve 12 b is, for example, a thin-walled portion provided on the battery lid 12 and has a groove-like slit. The gas discharge valve 12 b is split when the internal pressure of the container 10 rises and reaches a predetermined pressure, and the gas inside the container 10 is discharged to the outside to lower the internal pressure of the container 10. Ensure safety.

  FIG. 3 is a perspective view showing a state in which a part of the storage element 20 shown in FIG. 2 is developed. Storage element 20 is a power generation body of storage element 100. For example, a wound electrode obtained by winding long strip-like positive electrode body 21 and negative electrode body 22 with long strip-like separator 23 interposed therebetween. It is a group. The positive electrode body 21 has a long strip-like positive electrode foil 21a, a positive electrode mixture layer 21b formed on both sides of one end of the positive electrode foil 21a in the width direction, and a positive electrode foil 21a at one end in the width direction of the positive electrode foil 21a. And a foil exposed portion 21c exposed from the positive electrode mixture layer 21b.

  Similarly, the negative electrode body 22 includes a long strip-like negative electrode foil 22a, a negative electrode mixture layer 22b formed on both sides except one end in the width direction of the negative electrode foil 22a, and a negative electrode at one end in the width direction of the negative electrode foil 22a. Foil 22a has foil exposed portion 22c exposed from negative electrode mixture layer 22b. The positive electrode body 21 and the negative electrode body 22 are wound in a flat shape around the winding shaft 20A, and the respective foil exposed portions 21c and 22c are disposed at opposite positions in the direction of the winding shaft 20A. The storage element 20 wound into a flat shape has a flat portion 20F facing the thickness direction in which the positive electrode body 21 and the negative electrode body 22 are stacked flat, and the positive electrode body 21 and the negative electrode body 22 on both sides of the flat portion 20F. And a semi-cylindrical curved portion 20R which is curved and stacked in an arc shape.

  The external terminal 40 includes a positive electrode external terminal 40P connected to the positive electrode current collector plate 30P and a negative electrode external terminal 40N connected to the negative electrode current collector plate 30N. Positive electrode external terminal 40P is, for example, a member made of aluminum or an aluminum alloy. Negative electrode external terminal 40N is, for example, a member made of copper or a copper alloy. The shape of the positive electrode external terminal 40P and the shape of the negative electrode external terminal 40N are substantially the same. The external terminals 40 are disposed, for example, at one end and the other end of the battery lid 12 in the longitudinal direction.

  FIG. 4 is an enlarged exploded perspective view showing a state before the external terminal 40 and the current collector plate 30 are connected. The external terminal 40 has a terminal portion 41 disposed on the outer surface of the container 10, and a shaft portion 42 extending from the terminal portion 41 and penetrating the container 10. The external terminal 40 is integrally provided as one member, for example, by molding or cutting one metal material.

  The terminal portion 41 has, for example, a substantially rectangular block shape and is disposed on the top surface 10 t of the container 10, that is, the outer surface of the battery lid 12 via a gasket 70. The surface of the terminal portion 41 opposite to the battery lid 12 is, for example, generally parallel to the outer surface of the battery lid 12 and is a welded joint of the external terminal 40 for welding a metal plate bar.

  The shaft portion 42 extends, for example, along a central axis 42A orthogonal to the surface of the terminal portion 41 facing the battery lid 12, has a cylindrical portion 42a at the proximal end side, and has a cylindrical portion 42b at the distal end side There is. The outer diameter of the cylindrical portion 42b is smaller than the outer diameter of the cylindrical portion 42a, and a step is formed between the cylindrical portion 42a and the cylindrical portion 42b. The cylindrical portion 42 b has a hollow cylindrical end. The shaft portion 42 may have, for example, a slit extending along the central axis 42A of the shaft portion 42 at the tip of the hollow cylindrical cylindrical portion 42b.

  The shaft portion 42 may be a hollow cylinder as a whole, as long as the shaft portion 42 can be plastically deformed at the tip portion to form the enlarged diameter portion 43 (see FIG. 5) at the tip portion. It may be a real column. Further, the shaft portion 42 is not limited to a cylindrical or cylindrical shape having a circular cross-sectional shape, and may have a cylindrical shape or a columnar shape having a polygonal cross-sectional shape.

  Current collector plate 30 includes a positive electrode current collector plate 30P connected to positive electrode body 21 of storage element 20 and a negative electrode current collector plate 30N connected to negative electrode body 22 of storage element 20. The positive electrode current collector plate 30P is, for example, a plate-like member made of aluminum or an aluminum alloy. Negative electrode current collector plate 30N is a plate-like member made of, for example, copper or copper alloy. The shape of the positive electrode current collector plate 30P and the shape of the negative electrode current collector plate 30N are approximately mirror-symmetrical.

  Current collector plate 30 is provided with a relay portion 31 extending in a direction orthogonal to central axis 42 A of shaft portion 42, and a connection portion 32 provided at one end in the extending direction of relay portion 31 and connected to storage element 20. And a through hole 33 provided on the other end side of the connecting portion 32 in the extending direction of the relay portion 31. The relay portion 31 is a base portion of the current collector plate 30 fixed to the inner surface of the battery lid 12 via the insulating plate 60, and is a substantially rectangular plate-like portion disposed parallel to the battery lid 12.

  The connection portion 32 is bent substantially at right angles to the relay portion 31 at one end in the extension direction of the relay portion 31 and extends toward the bottom surface 10 b of the container 10 generally in parallel to the central axis 42 A of the shaft portion 42. More specifically, in the example illustrated in FIG. 2 and FIG. 4, the connection portion 32 is one side edge of the relay portion 31 facing the wide side 10 w of the container 10 and the extension direction of the relay portion 31, that is, the container 10 The one side edge of the relay portion 31 along the width direction of the container 10 is connected to one end of the outer relay portion 31 in the width direction of the container 10 adjacent to the narrow side surface 10 n of the container 10. Further, connection portion 32 is arranged along foil exposed portion 21 c of positive electrode body 21 and foil exposed portion 22 c of negative electrode body 22 wound and bundled respectively at one end and the other end in the direction of winding axis 20 A of storage element 20. It extends.

  Insulating sheet 50 is, for example, a resin sheet having flexibility and electrical insulation. Insulating sheet 50 is arranged to cover storage element 20 and the periphery of current collecting plate 30 joined to storage element 20, so that between storage element 20 and battery can 11, and current collection plate 30. And the battery can 11 are electrically isolated. The insulating plate 60 is, for example, a hard resin member having an electrical insulation property, and has a through hole 61 through which the shaft portion 42 of the external terminal 40 passes. The insulating plate 60 is disposed between the relay portion 31 of the current collector plate 30 and the battery lid 12 to electrically insulate between them.

  The gasket 70 is, for example, a resin member having flexibility and electrical insulation. The gasket 70 has a main body 71 that covers the end of the side and the side facing the battery lid 12 of the terminal 41 of the external terminal 40, a through hole 72 provided in the main body 71, and a shaft 42 of the external terminal 40. And a tubular portion 73 covering the proximal end portion of the The main body portion 71 of the gasket 70 electrically insulates between the terminal portion 41 of the external terminal 40 and the battery cover 12. The cylindrical portion 73 of the gasket 70 electrically insulates between the shaft portion 42 of the external terminal 40 and the through hole 12 a of the battery lid 12. Further, the gasket 70 seals the through hole 12 a of the battery lid 12 by the main body 71 being compressed between the terminal 41 of the external terminal 40 and the battery lid 12.

  Next, an example of an assembly procedure of the storage element 100 of the present embodiment will be described. First, as shown in FIG. 4, the shaft portion 42 of the external terminal 40 includes the through hole 72 of the gasket 70, the through hole 12 a of the battery cover 12, the through hole 61 of the insulating plate 60, and the relay portion 31 of the current collector plate 30. The through holes 33 are sequentially penetrated. Next, the tip of the shaft portion 42 of the external terminal 40 penetrating the through hole 33 of the relay portion 31 of the current collector plate 30 is plastically deformed and expanded in diameter, whereby the diameter is larger than the inner diameter of the through hole 33 of the relay portion 31 An enlarged diameter portion 43 (see FIG. 5) which is expanded in diameter and connected to the relay portion 31 is formed.

  FIG. 5 is an enlarged cross-sectional view of the vicinity of the external terminal 40 in the caulking process, which is a part of the manufacturing process of the storage element 100. FIG. 6 is a schematic plan view of the enlarged diameter portion 43 formed by the caulking process shown in FIG. The tip end portion of the shaft portion 42 of the external terminal 40 penetrating the through hole 72 of the gasket 70, the through hole 12a of the battery lid 12, the through hole 61 of the insulating plate 60, and the through hole 33 of the relay portion 31 of the current collector plate 30 For example, pressure is applied so as to be crushed in the direction of the central axis 42A of the shaft portion 42 by the caulking tool T.

  As a result, the tip end of the shaft 42 of the external terminal 40 is expanded radially outward by the caulking tool T, and the diameter of the enlarged diameter portion 43 is increased by the diameter of the through hole 33 of the relay portion 31 of the current collector plate 30. It is formed. In the enlarged diameter portion 43, the connection surface 43 </ b> F facing the relay portion 31 of the current collector plate 30 is pressed against the relay portion 31 of the current collector plate 30 and electrically connected to the relay portion 31. At this time, the relay portion 31 of the current collector plate 30 engages, for example, a step between the base portion and the tip portion of the shaft portion 42, and between the step and the enlarged diameter portion 43 at the tip of the shaft portion 42. It is pinched. Thus, with the gasket 70 compressed by a predetermined amount of deformation between the terminal portion 41 of the external terminal 40, the enlarged diameter portion 43 and the battery cover 12, the external terminal 40, the gasket 70, The insulating plate 60 and the current collector plate 30 can be fixed.

  Further, as described above, in the case where the shaft portion 42 has a slit extending along the central axis 42A of the shaft portion 42 at the tip end of the hollow cylindrical cylindrical portion 42b, this slit serves as the enlarged diameter portion 43. The radially outer portion is expanded in the circumferential direction of the enlarged diameter portion 43, and a wedge-shaped, V-shaped or sector-shaped notch portion 44 is formed in the enlarged diameter portion 43. Further, when the shaft portion 42 does not have a slit at the tip end portion, the caulking tool T is provided with a convex portion or a blade for forming a cut at the tip end portion of the shaft portion 42. The diameter portion 43 can be formed.

  Thus, by forming the notches 44 in the enlarged diameter portion 43 in the caulking step, plastic deformation of the shaft portion 42 when forming the enlarged diameter portion 43 as compared with the case where the notches 44 are not formed. Can be reduced. More specifically, when the enlarged diameter portion 43 does not have the notch portion 44, the plastic deformation in the circumferential direction of the enlarged diameter portion 43 becomes larger toward the outer side in the radial direction. Then, there is a possibility that the crack resulting from work hardening and ductility reduction may occur in the enlarged diameter portion 43. When heat treatment is performed to prevent such a crack, the manufacturing cost of the storage element 100 is increased.

  On the other hand, when the enlarged diameter portion 43 has the notched portion 44 cut out in the radial direction of the shaft portion 42, the diameter of the tip end of the shaft portion 42 is expanded to form the enlarged diameter portion 43. Plastic deformation in the circumferential direction of the shaft portion 42 can be reduced. Therefore, it is possible to prevent the occurrence of cracking due to work hardening and ductility reduction in the enlarged diameter portion 43 without performing heat treatment. However, when notch 44 of enlarged diameter portion 43 is provided in a portion where current density between external terminal 40 and storage element 20 is high, the flow of current is interrupted, and external terminal 40 and storage element 20 There is a risk that the electrical resistance between them will rise.

  In order to prevent such an increase in the electrical resistance between the external terminal 40 and the storage element 20, the storage element 100 of the present embodiment is characterized by having the following configuration. Of the two half parts 43A and 43B divided by the center axis 42A of the shaft part 42 and the center line C1 orthogonal to the extending direction of the relay part 31 in the enlarged diameter part 43, it approaches the connection part 32 of the current collector plate 30. The first half portion 43A has a larger area of the connection surface 43F facing the relay portion 31 of the current collector plate 30 than the second half portion 43B separated from the connection portion 32 of the current collector plate 30.

  In the first half portion 43A and the second half portion 43B of the enlarged diameter portion 43, the connection surface 43F facing the relay portion 31 of the current collector plate 30 is electrically connected to the relay portion 31 in contact with the relay portion 31. ing. Therefore, the first half portion 43A and the second half portion 43B of the enlarged diameter portion 43 are electrically connected to the relay portion 31 as the area of the connection surface 43F facing the relay portion 31 of the current collector plate 30 increases. The area increases and the electrical resistance decreases. That is, the first half portion 43A closer to the connection portion 32 of the current collector plate 30 is closer to the relay portion 31 of the current collector plate 30 than the second half portion 43B separated from the connection portion 32 of the current collector plate 30. Low electrical resistance. The connecting surface 43 F of the first half portion 43 A and the second half portion 43 B of the enlarged diameter portion 43 is generally in contact with the relay portion 31 of the current collector plate 30.

  In the storage element 100 of the present embodiment, the enlarged diameter portion 43 of the shaft portion 42 of the external terminal 40 has a single notched portion 44 in the second half portion 43B separated from the connection portion 32 of the current collector plate 30. There is. In the example shown in FIG. 6, the notch 44 of the second half 43 B is disposed on the center line C 2 which is orthogonal to the central axis 42 A of the shaft 42 and parallel to the extending direction of the relay portion 31. Further, in the example shown in FIG. 6, the connection portion 32 of the current collector plate 30 is opposed to the narrow side surface 10 n of the container 10 at one end in the extension direction of the relay portion 31 unlike the example shown in FIGS. It is bent substantially at right angles from the side edge of the relay portion 31 and extends along the narrow side 10 n of the container 10 toward the bottom surface 10 b of the container 10.

  In addition, in the storage element 100 of the present embodiment, the notch 44 provided in the enlarged diameter portion 43 of the shaft portion 42 of the external terminal 40 has a through hole as the end portion 44a inside in the radial direction of the enlarged diameter portion 43 It is provided outside the opening edge 33a of 33. In the example shown in FIG. 6, the notch portion 44 has a wedge shape, a V shape, or a sector shape, and the dimension in the circumferential direction of the enlarged diameter portion 43 is smaller toward the radial inside of the enlarged diameter portion 43. It has become. The strength of the enlarged diameter portion 43 is, for example, continued along the entire circumferential direction of the enlarged diameter portion 43 and is engaged with the outside of the through hole 33 of the relay portion 31 of the current collector plate 30. Is determined as the strength of the annular portion 43C of That is, the strength of the enlarged diameter portion 43 can be obtained, for example, by integrating the radial dimension 43 d of the annular portion 43 C of the enlarged diameter portion 43 and the thickness 43 t (see FIG. 5).

  As described above, the enlarged diameter portion 43 is formed by plastic deformation of the distal end portion of the shaft portion 42 of the external terminal 40 to electrically connect the shaft portion 42 of the external terminal 40 and the relay portion 31 of the current collector plate 30. The external terminal 40, the gasket 70, the insulating plate 60, and the current collector plate 30 can be crimped and fixed to the battery lid 12. Thereafter, connection portion 32 of current collector plate 30 is connected to storage element 20.

  More specifically, as shown in FIG. 2, the storage element 20 has, for example, one end of the winding axis 20A disposed parallel to the width direction of the container 10, ie, the longitudinal direction of the battery cover 12, The foil exposed portion 21c of the positive electrode body 21 and the foil exposed portion 22c of the negative electrode body 22 wound around the other end are compressed and bundled at the flat portion 20F. The connection portion 32 of the current collector plate 30 is disposed opposite to the portion where the foil exposed portions 21c and 22c of the storage element 20 are bundled. For example, the foil exposed portions 21c and 22c of the storage element 20 are ultrasonically bonded. And electrically connected. As a result, the positive electrode external terminal 40P and the negative electrode external terminal 40N are electrically connected to the positive electrode body 21 and the negative electrode body 22 of the storage element 20 via the positive electrode current collector plate 30P and the negative electrode current collector plate 30N, respectively.

  Next, the storage element 20 joined to the current collector plate 30 and fixed to the battery lid 12 via the current collector plate 30 is covered with the current collector plate 30 by the insulating sheet 50, and the opening of the battery can 11 of the container 10 11a is inserted into the inside of the battery can 11. Then, the whole of the current collecting plate 30, the storage element 20 and the insulating sheet 50 covering them are accommodated inside the battery can 11, and the opening 11 a of the battery can 11 is closed by the battery lid 12. After that, for example, the battery lid 12 is joined to the upper end of the battery can 11 over the entire circumference by laser welding, and the opening 11a of the battery can 11 is sealed and sealed by the battery lid 12, and the battery can 11 and the battery lid The container 12 which accommodates the current collection board 30 and the electrical storage element 20 is comprised by 12.

  Thereafter, for example, an electrolytic solution is injected into the inside of the container 10 through the liquid injection port 12d provided in the battery lid 12, and the liquid injection port 12d is closed by the liquid injection plug 12c. The liquid injection port 12 d is sealed and sealed by the liquid injection plug 12 c by bonding the entire circumference of the battery cover 12 to the battery cover 12. Thus, the storage element 100 in the form shown in FIG. 1 can be assembled.

  Hereinafter, the operation of the storage element 100 of the present embodiment will be described.

  FIG. 7 is an enlarged front view showing an example of the path of the current I in the storage element 100 of the present embodiment. In addition, illustration of the battery can 11 of the container 10, the insulation sheet 50 grade | etc., Is abbreviate | omitted in FIG.

  As described above, for example, the storage element 100 of the present embodiment is mounted on a vehicle and supplies power to an apparatus that consumes power, such as a motor. At this time, a current I flows from the foil exposed portion 21 c of the storage element 20 to the connection portion 32 of the current collector plate 30. The current I flowing through the connection portion 32 of the current collector plate 30 flows from the connection portion 32 to the relay portion 31 and flows from the relay portion 31 to the enlarged diameter portion 43 of the shaft portion 42 of the external terminal 40. The current I flowing to the enlarged diameter portion 43 of the shaft portion 42 of the external terminal 40 flows to the terminal portion 41 via the shaft portion 42, and consumes power such as a motor from the terminal portion 41 via a bus bar or wiring. It is supplied to the equipment.

  Further, as described above, the storage element 100 of the present embodiment stores, for example, the power supplied from a device such as a generator that generates power. At this time, a current I flows from the device such as a generator to the terminal portion 41 of the external terminal 40 through the wiring, the bus bar, and the like. The current I having flowed to the terminal portion 41 flows to the enlarged diameter portion 43 at the tip of the shaft portion 42 via the shaft portion 42. The current I that has flowed to the enlarged diameter portion 43 flows to the connection portion 32 through the relay portion 31 of the current collector plate 30, flows from the connection portion 32 to the foil exposed portion 21c of the storage element 20, and power is stored in the storage element 20. Be

  That is, in the storage element 100 of the present embodiment, the current I flows in the direction of the central axis 42A of the shaft portion 42 between the terminal portion 41 of the external terminal 40 and the shaft portion 42. Further, the current I is between the axial portion 42 of the external terminal 40 and the connection portion 32 of the current collector plate 30 in the extending direction of the relay portion 31 orthogonal to the central axis 42A of the axial portion 42, ie, the width of the container 10. Flow in the direction. Furthermore, the current I flows in the extending direction of the connection portion 32 of the current collector plate 30, that is, in the height direction of the container 10, between the relay portion 31 of the current collector plate 30 and the storage element 20.

  That is, as shown in FIG. 6, the first half portion 43A of the enlarged diameter portion 43 adjacent to the connection portion 32 of the current collector plate 30 is a part of the main current path between the external terminal 40 and the storage element 20. Thus, the current density is higher than that of the second half 43B. On the other hand, the second half 43B of the enlarged diameter portion 43 separated from the connection portion 32 of the current collector plate 30 deviates from the main current path between the external terminal 40 and the storage element 20 and is more than the first half 43A. The current density is reduced.

  Here, as described above, the storage element 100 of the present embodiment has the following configuration. The storage element 100 mainly includes a container 10, a storage element 20 housed in the container 10, a current collector plate 30 connected to the storage element 20 and housed in the container 10, and the current collector plate 30. And an external terminal 40 connected and disposed on the outer surface of the container 10. The external terminal 40 has a terminal portion 41 disposed on the outer surface of the container 10, and a shaft portion 42 extending from the terminal portion 41 and penetrating the container 10. Current collector plate 30 is provided with a relay portion 31 extending in a direction orthogonal to central axis 42 A of shaft portion 42, and a connection portion 32 provided at one end in the extending direction of relay portion 31 and connected to storage element 20. And a through hole 33 provided on the other end side of the connecting portion 32 in the extending direction of the relay portion 31. The shaft portion 42 has an enlarged diameter portion 43 which is larger in diameter than the inner diameter of the through hole 33 and connected to the relay portion 31 at a tip end portion which penetrates the through hole 33. The enlarged diameter portion 43 has a notch 44 cut in the radial direction of the shaft portion 42. Furthermore, the enlarged diameter portion 43 is the first one of the two half portions 43A, 43B divided by the center axis C1 of the shaft portion 42 and the center line C1 orthogonal to the extending direction of the relay portion 31. The half portion 43A has a larger area of the connection surface 43F facing the relay portion 31 than the second half portion 43B separated from the connection portion 32.

  As described above, in the storage element 100 of the present embodiment, the enlarged diameter portion 43 has the notch portion 44 cut out in the radial direction of the shaft portion 42. Therefore, as described above, the distal end portion of the shaft portion 42 of the external terminal 40 penetrating the through hole 33 of the relay portion 31 of the current collector plate 30 is plastically deformed to expand the diameter to form the enlarged diameter portion 43, When the external terminal 40 and the current collector plate 30 are connected, the notch 44 suppresses plastic deformation of the tip of the shaft 42. As a result, work hardening and ductility reduction are suppressed in the enlarged diameter portion 43 of the external terminal 40, and cracking can be prevented without heat treatment.

  In addition, in the storage element 100 of the present embodiment, as described above, the current density is relatively high between the first half 43A and the second half 43B of the enlarged diameter portion 43. The area of the connection surface 43F is made larger than the connection surface 43F of the second half 43B of the enlarged diameter portion 43 where the current density is relatively low. Thereby, the increase in the electrical resistance between the external terminal 40 and the storage element 20 can be suppressed, and the electrical resistance can be reduced. Therefore, according to storage element 100 of the present embodiment, cracking of external terminal 40 connected to current collector plate 30 can be prevented without performing heat treatment, and external terminal 40 and storage element 20 Thus, it is possible to provide a storage element 100 capable of reducing the electrical resistance between the two.

  In addition, in the storage element 100 of the present embodiment, the first half 43A and the second half 43B of the enlarged diameter portion 43 each contact the relay portion 31 of the current collector plate 30 with the connection surface 43F in contact with the relay portion 31. It is electrically connected. Therefore, the area of the current path between the first half 43A and the relay portion 31 of the current collector plate 30 and the area of the current path between the second half 43B and the relay portion 31 of the current collector 30 are They are respectively proportional to the area of the connecting surface 43F of the first half 43A and the area of the connecting surface 43F of the second half 43B. Therefore, by making the area of the connection surface 43F of the first half 43A larger than the area of the connection surface 43F of the second half 43B, the space between the first half 43A and the relay portion 31 of the current collector plate 30 can be obtained. The area of the current path is larger than the area of the current path between the second half 43B and the relay portion 31 of the current collector plate 30. Therefore, according to the storage element 100 of the present embodiment, the electrical resistance between the external terminal 40 and the storage element 20 can be reduced.

  Further, in the storage element 100 of the present embodiment, the enlarged diameter portion 43 has the only notch portion 44 in the second half portion 43B. That is, since the enlarged diameter part 43 does not have the notch part 44 in the 1st half part 43A, the area of the connection surface 43F of the 1st half part 43A can be enlarged. Therefore, according to the storage element 100 of the present embodiment, the electrical resistance between the external terminal 40 and the storage element 20 can be reduced.

  Further, in the storage element 100 of the present embodiment, the notched portion 44 of the enlarged diameter portion 43 is provided with the inner end 44 a in the radial direction of the enlarged diameter portion 43 outside the opening edge 33 a of the through hole 33. ing. In this case, the strength of the enlarged diameter portion 43 can be maintained, and the relay portion 31 of the current collector plate 30 can be firmly fixed to the battery lid 12 via the insulating plate 60 by the enlarged diameter portion 43. More specifically, as described above, the annular portion 43C is formed in the circumferential direction in the enlarged diameter portion 43, and the strength of the enlarged diameter portion 43 obtained from the integration of the radial dimension 43d of the annular portion 43C and the thickness 43t. Can be secured.

  As described above, according to the present embodiment, cracking of the external terminal 40 connected to the current collector plate 30 can be prevented without performing heat treatment, and the external terminal 40 and the storage element 20 Thus, it is possible to provide a storage element 100 capable of reducing the electrical resistance between the two.

Second Embodiment
Next, with reference to FIG. 8 to FIG. 11, a storage element according to Embodiment 2 of the present invention will be described. FIG. 8 is a schematic plan view of the enlarged diameter portion 43 of the energy storage device according to Embodiment 2 of the present invention. FIG. 9 is a distribution diagram of current density in the vicinity of the enlarged diameter portion 43 of the energy storage device of this embodiment. FIG. 10 is a distribution diagram of current density in the vicinity of the enlarged diameter portion 43 of the storage element of the comparative embodiment. FIG. 11 is a graph showing the rate of increase in resistance of the storage element of the present embodiment and the storage element of the comparative embodiment. The distribution diagrams shown in FIG. 9 and FIG. 10 are shown in a lighter color closer to white as the current density is lower, and in a darker color closer to black as the current density is higher.

  The storage element of the present embodiment is, as shown in FIG. 8, between the enlarged diameter portion 43 of the shaft portion 42 of the external terminal 40 and the relay portion 31 of the current collector plate 30, the enlarged diameter portion 43 and the relay portion The storage element 100 is different from the storage element 100 according to the above-described first embodiment in that it has a weld portion W for joining the third part 31 and the third part. The other parts of the storage element of this embodiment are the same as those of the storage element 100 of Embodiment 1 described above, so the same parts will be denoted by the same reference numerals and redundant description will be omitted.

  The enlarged diameter portion 43 of the shaft portion 42 of the external terminal 40 and the relay portion 31 of the current collector plate 30 are welded, for example, by high energy beam welding which emits a high energy beam such as a laser or electron beam. A welded portion W is formed between the and the relay portion 31. In the example shown in FIG. 8, the enlarged diameter portion 43 has a plurality of welded portions W arranged in line symmetry with respect to a center line C2 parallel to the extending direction of the relay portion 31 of the current collector plate 30. More specifically, in the example shown in FIG. 8, the welding portion W has an enlarged diameter portion 43 orthogonal to the extending direction of the central axis 42 A of the shaft portion 42 of the external terminal 40 and the relay portion 31 of the current collector plate 30. A total of two are formed at positions where the center line C1 and the outer edge of the enlarged diameter portion 43 intersect. The weld portion W is provided to avoid the notch portion 44.

  Further, in the example shown in FIG. 8, the counterclockwise angle is set in the circumferential direction of the enlarged diameter portion 43, and the angle of one welding portion W is set to 0 degrees, and the position of the other welding portion W is set to 180 degrees. And the peripheral part of the second half part 43B of the enlarged diameter part 43 is in the angle range from 0 degree to 180 degrees, and the peripheral part of the first half part 43A of the enlarged diameter part 43 is from 180 degrees to 360 degrees Suppose it is in the angle range. That is, in the example shown in FIG. 8, the notch portion 44 is formed at a position of 90 degrees of the second half portion 43 </ b> B of the enlarged diameter portion 43.

  On the other hand, in the storage element of the comparative form shown in FIG. 10, the notch 44 is formed at a position of 270 degrees of the first half 43A of the enlarged diameter portion 43. In this case, the area of the connection surface 43F of the enlarged diameter portion 43 facing the relay portion 31 of the current collector plate 30 decreases in the first half 43A having a higher current density than the second half 43B. Therefore, as shown in FIG. 11, the storage element of the comparative embodiment shown in FIG. 10 has an electric resistance between storage element 20 and external terminal 40, compared to the storage element of the present embodiment shown in FIG. For example, there is a risk of rising by about 10%.

  On the other hand, in the storage element of the present embodiment shown in FIG. 9, the notch 44 is formed at a position of 90 degrees of the second half 43 B of the enlarged diameter portion 43. In this case, the area of the connection surface 43F of the enlarged diameter portion 43 facing the relay portion 31 of the current collector plate 30 decreases in the second half 43B having a lower current density than the first half 43A. However, the area of the connecting surface 43F of the enlarged diameter portion 43 does not decrease in the first half 43A having a higher current density than the second half 43B, and maintains the same area as in the case where the notch 44 is not provided. be able to.

  Therefore, according to the present embodiment, as in the first embodiment described above, cracking of the external terminal 40 connected to the current collector plate 30 can be prevented without performing heat treatment, and the external terminal 40 and It is possible to provide a storage element capable of reducing the electrical resistance between the storage element 20 and the storage element 20.

  Furthermore, as described above, the storage element of the present embodiment has a welding portion W for joining the enlarged diameter portion 43 and the relay portion 31 between the enlarged diameter portion 43 and the relay portion 31 of the current collector plate 30. doing. Thus, not only the bonding strength between the enlarged diameter portion 43 and the relay portion 31 of the current collector plate 30 is improved, but the enlarged diameter portion 43 and the relay portion 31 of the current collector plate 30 are electrically Connected to Thereby, the electrical resistance between external terminal 40 and storage element 20 can be further reduced.

  Further, in the storage element of the present embodiment, since enlarged diameter portion 43 has a plurality of welded portions W, external terminal 40 and storage element 20 are compared with the case where only one welded portion W is provided. Resistance can be further reduced. Furthermore, in the enlarged diameter portion 43, the plurality of welding portions W are disposed in line symmetry with respect to a center line C2 parallel to the extending direction of the relay portion 31. Thereby, the bias of the current I flowing through each welding portion W can be suppressed, and the current I flowing through each welding portion W can be made more uniform, and between the external terminal 40 and the storage element 20 Electrical resistance can be further reduced.

Third Embodiment
Next, with reference to FIG. 12, a storage element according to Embodiment 3 of the present invention will be described. FIG. 12 is a schematic plan view of the enlarged diameter portion 43 of the energy storage device according to Embodiment 3 of the present invention. The storage element of the present embodiment is different from the storage element according to the second embodiment in the configuration of the welding portion W. The other configuration of the storage element of the present embodiment is the same as that of the storage element according to the above-described second embodiment, so the same reference numerals are given to the same parts, and the overlapping description will be omitted.

  In the storage element of the present embodiment, welding portion W is expanded with center line C1 of enlarged diameter portion 43 orthogonal to the extending direction of central axis 42A of shaft portion 42 of external terminal 40 and relay portion 31 of current collector plate 30. It is provided in a predetermined angular range in the circumferential direction of the enlarged diameter portion 43 around a position where the outer edge of the diameter portion 43 intersects. Such a welded portion W can be formed, for example, by continuously irradiating a high energy beam in the circumferential direction of the enlarged diameter portion 43. Thus, by enlarging the area where the weld portion W is formed, the area where the enlarged diameter portion 43 and the relay portion 31 of the current collector plate 30 are electrically connected via the weld portion W is expanded. Thus, the electrical resistance between the external terminal 40 and the storage element 20 can be further reduced.

Fourth Embodiment
Next, with reference to FIG. 13, a storage element according to Embodiment 4 of the present invention will be described. FIG. 13 is a schematic plan view of the enlarged diameter portion 43 of the energy storage device according to Embodiment 4 of the present invention. The storage element of the present embodiment is different from the storage element according to the third embodiment in the configuration of the notch portion 44. The other configuration of the storage element of the present embodiment is the same as that of the storage element according to the third embodiment described above, so the same parts are denoted with the same reference numerals and redundant description will be omitted.

  In the storage element of the present embodiment, the enlarged diameter portion 43 has a plurality of notches 44. In the enlarged diameter portion 43, the number of notches 44 provided in the second half 43B is larger than the number of notches 44 provided in the first half 43A. Thus, in the storage element of the present embodiment, the first half 43A in the vicinity of the connection portion 32 of the current collector plate 30 is closer to the current collector than the second half 43B separated from the connection portion 32 in the current collector plate 30. The area of the connection surface 43F facing the relay portion 31 of the plate 30 is large.

  Therefore, according to the storage element of the present embodiment, it is possible to obtain the same effect as the storage element of the first to third embodiments described above. Furthermore, when forming the enlarged diameter portion 43 by plastically deforming the tip end portion of the shaft portion 42 of the external terminal 40, the plurality of notches 44 more effectively suppress plastic deformation of the tip end of the shaft portion 42. Can. As a result, work hardening and ductility reduction are further suppressed in the enlarged diameter portion 43 of the external terminal 40, and cracking of the enlarged diameter portion 43 can be more reliably prevented without heat treatment.

Fifth Embodiment
Next, with reference to FIG. 14, a storage element according to Embodiment 5 of the present invention will be described. FIG. 14 is a schematic plan view of the enlarged diameter portion 43 of the energy storage device according to Embodiment 5 of the present invention. The storage element of the present embodiment is different from the storage element according to the second embodiment in the configuration of the notch 44. The other configuration of the storage element of the present embodiment is the same as that of the storage element according to the above-described second embodiment, so the same reference numerals are given to the same parts, and the overlapping description will be omitted.

  In the storage element of the present embodiment, the notch portion 44 has an arc-shaped stress relieving portion 44 </ b> R at the inner end portion 44 a in the radial direction of the enlarged diameter portion 43. With this configuration, for example, when stress acts in the circumferential direction of enlarged diameter portion 43, stress can be prevented from concentrating on end portion 44a inside notch 44 in the radial direction of enlarged diameter portion 43. . Thereby, when stress acts in the circumferential direction of enlarged diameter portion 43, generation of a crack can be prevented starting from end portion 44a on the inner side of notch 44 in the radial direction of enlarged diameter portion 43. .

  As mentioned above, although the embodiment of the present invention has been described in detail using the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like within the scope of the present invention. Also, they are included in the present invention. For example, the storage element is not limited to a secondary battery, and includes an electrochemical element capable of storing power, such as a primary battery, an electric double layer capacitor, and a capacitor.

DESCRIPTION OF SYMBOLS 10 container 20 electrical storage element 30 current collecting plate 31 relay part 32 connection part 33 through hole 33a opening edge 40 external terminal 41 terminal part 42 shaft part 42A central axis 43 enlarged diameter part 43A first half part 43B second half part 43F connection surface 44 notch 44a end 44R stress relaxation unit 100 storage element C1 center line C2 center line W weld

Claims (8)

A container, a storage element accommodated in the container, a current collector plate connected to the storage element and contained in the container, an external terminal connected to the current collector plate and disposed on the outer surface of the container A storage element comprising
The external terminal includes a terminal portion disposed on the outer surface of the container, and a shaft portion extending from the terminal portion and penetrating the container.
The current collector plate is a relay portion extending in a direction orthogonal to the central axis of the shaft portion, a connection portion provided at one end of the relay portion in the extension direction and connected to the storage element, and the connection And a through hole provided on the other end side in the extending direction of the relay portion than the portion;
The shaft portion has an enlarged diameter portion whose diameter is larger than the inner diameter of the through hole and connected to the relay portion at a tip end portion which penetrates the through hole.
The enlarged diameter portion has notches cut in a radial direction of the shaft portion, and two halves divided by a central axis of the shaft portion and a center line orthogonal to the extending direction of the relay portion A storage element characterized in that among the parts, a first half part close to the connection part has a larger area of a connection surface facing the relay part than a second half part separated from the connection part.   The storage element according to claim 1, wherein the connection surface of the first half portion and the second half portion is electrically connected to the relay portion while the connection surface is in contact with the relay portion.   The storage element according to claim 1, further comprising: a welding portion that joins the enlarged diameter portion and the relay portion between the enlarged diameter portion and the relay portion.   The storage element according to claim 3, wherein the enlarged diameter portion includes a plurality of the welded portions arranged in line symmetry with respect to a center line parallel to the extending direction of the relay portion.   The storage element according to claim 1, wherein the enlarged diameter portion has only one notch in the second half. The enlarged diameter portion has a plurality of the notched portions,
The storage element according to claim 1, wherein the number of the notches provided in the second half is larger than the number of the notches provided in the first half.   2. The storage element according to claim 1, wherein an end of the notched portion in the radial direction of the enlarged diameter portion is provided outside an opening edge of the through hole.   The energy storage device according to claim 1, wherein the notch has an arc-shaped stress relieving portion at an inner end in a radial direction of the enlarged diameter portion.

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