JP6529806B2 - Secondary battery and assembled battery - Google Patents

Description

  The present invention relates to a secondary battery and an assembled battery in which a plurality of secondary batteries are connected.

  Patent Document 1 describes that in a rectangular lithium ion secondary battery, an aluminum-based metal is used as a core of a positive electrode, and a copper-based metal is generally used as a core of a negative electrode. Also, it is stated that the same aluminum-based metal as the positive electrode is used as the material of the positive electrode external electrode welded to the positive electrode side, and the same copper-based metal as the negative electrode is used as the material of the negative electrode external electrode welded to the negative electrode side There is.

JP, 2013-157130, A

  An object of the present invention is to provide a secondary battery and an assembled battery capable of reducing the influence of welding.

  The secondary battery according to the present invention is mounted on an electrode body having a positive electrode and a negative electrode, an exterior body having an opening and accommodating the electrode body, a sealing plate for sealing the opening of the exterior body, and the sealing plate A positive electrode terminal electrically connected to the positive electrode, and a negative electrode terminal inserted in the negative electrode terminal mounting hole provided in the sealing plate via the negative electrode side insulating member and electrically connected to the negative electrode; A negative electrode current collector electrically connecting between the negative electrode and the negative electrode terminal and an external conductive member connected to the negative electrode terminal and made of an aluminum-based metal are provided on the terminal side, and the negative electrode current collector The flange portion has a current collector through hole into which the negative electrode terminal is inserted, and the negative electrode terminal has an outer area larger than the opening area of the negative electrode terminal mounting hole, and is disposed on the outer surface side of the sealing plate; An insertion portion connected to one surface of the flange portion, through the negative electrode terminal mounting hole and the current collector And the distal end side is connected to the negative electrode current collector, and has a first region made of copper-based metal and a second region made of aluminum-based metal. A region is formed, and a boundary between the first region and the second region is provided in the flange portion, and the external conductive member is connected to the second region.

  An assembled battery according to the present invention is an assembled battery configured by connecting a plurality of the above-mentioned secondary batteries, and is an external conductive body having one end connected to the negative electrode terminal of the secondary battery on one side in adjacent secondary batteries. The other end of the member is connected to the other positive electrode terminal of the secondary battery.

  The secondary battery and the battery assembly according to the present invention can reduce the influence of welding.

It is a perspective view of the secondary battery of the embodiment concerning the present invention. It is a top view about the positive electrode terminal side of FIG. It is sectional drawing along the AA of FIG. Fig.3 (a) is a figure which shows the state before a welding process, (b) is a figure which shows the state after a welding process. It is a top view about the negative electrode terminal side of FIG. It is sectional drawing along the BB line of FIG. Fig.5 (a) is a figure which shows the state before a welding process, (b) is a figure which shows the state after a welding process. It is the figure which extracted the part of the negative electrode terminal about Fig.5 (a). It is a figure which shows some modifications about a negative electrode terminal. It is a figure which shows the connection state of two adjacent secondary batteries about the assembled battery of embodiment which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The materials, dimensions, shapes, and the like described below are examples for the purpose of explanation, and can be appropriately changed according to the specifications of the secondary battery. In the following, the corresponding elements in all the drawings are denoted by the same reference numerals and redundant description will be omitted.

  FIG. 1 is an external perspective view of a secondary battery 10. The secondary battery 10 is a prismatic lithium ion battery having a bottomed cylindrical rectangular outer package 12. Inside the secondary battery 10, an electrode body 14 formed by laminating and winding a positive electrode and a negative electrode with a separator interposed therebetween and formed into a flat shape is accommodated including a non-aqueous electrolyte. FIG. 1 shows three directions of orthogonal XYZ. The Z direction is the axial direction of the exterior body 12 and the + Z direction is the opening side of the exterior body 12. The Y-axis direction is the lateral direction of the package 12, and the positive electrode terminal side is the + Y direction, and the negative electrode terminal side is the -Y direction. The X direction is the thickness direction of the exterior body 12.

  The exterior body 12 is a rectangular bottomed tubular shape having a bottom portion, and is a rectangular parallelepiped rectangular container whose top in the + Z direction is open. As this exterior body 12, what shape | molded the metal material in the predetermined shape is used. As a metal material used for the exterior body 12, aluminum-based metal (aluminum, aluminum alloy mainly containing aluminum), iron-based metal (iron, iron alloy mainly containing iron), etc. are preferable.

  The electrode assembly 14 shown by a broken line in FIG. 1 is formed by laminating and winding a positive electrode and a negative electrode with a separator interposed therebetween to form a flat shape, and the positive electrode current collector 16 is at the end of the flat forming body in the + Y direction. The negative electrode current collector 18 is connected to the end in the -Y direction.

  The positive electrode is one in which a positive electrode active material layer is formed on both sides of a metal foil as a positive electrode core body. It is preferable to use an aluminum-based metal foil as the positive electrode core body. The aluminum-based metal is aluminum or an aluminum alloy mainly composed of aluminum. The positive electrode active material contains a lithium transition metal oxide capable of absorbing and discharging lithium ions. The negative electrode is obtained by forming a negative electrode active material layer on both sides of a metal foil as a negative electrode core body. It is preferable to use a copper-based metal foil as the negative electrode core body. The copper-based metal is copper or a copper alloy mainly composed of copper. The negative electrode active material is a carbonaceous material. The separator is composed of an ion permeable material.

A non-aqueous electrolytic solution is prepared by adding lithium hexafluorophosphate (LiPF ₆ ) as an electrolyte salt, using ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC) or the like as a non-aqueous solvent It is.

  The above-mentioned composition substance is an illustration for explanation, and the composition substance other than this can be used according to the specification of a lithium ion secondary battery.

  The electrode body 14 is formed by laminating a positive electrode, a separator and a negative electrode, winding and flattening. The positive electrode current collector 16 is a conductive lead terminal material connected to the positive electrode core exposed at the + Y direction end of the electrode body 14. The positive electrode current collector 16 is formed by processing an aluminum-based metal plate. Welding is used as a connection means between the positive electrode current collector 16 and the positive electrode core. The negative electrode current collector 18 is a conductive lead terminal material connected to the negative electrode core exposed at the end of the electrode body 14 in the -Y direction. The negative electrode current collector 18 is formed by processing a copper-based metal plate. Welding is used as a connection means between the negative electrode current collector 18 and the negative electrode core body.

  The sealing plate 20 is a lid plate for closing the opening of the exterior body 12. The sealing plate 20 and the exterior body 12 are integrated by welding, and the electrode body 14, the positive electrode current collector 16, the negative electrode current collector 18 and the like are accommodated in the internal space. The sealing plate 20 is provided in the internal space in which the gas exhaust valve 22 that releases the internal pressure when the pressure in the internal space formed by the exterior body 12 and the sealing plate 20 exceeds the threshold pressure, and the electrode body 14 and the like. A liquid injection hole into which the non-aqueous electrolyte is injected and its sealing stopper 24 are provided. As the sealing plate 20, an aluminum plate processed into a predetermined shape is used. Welding is used as an integrated means of the sealing board 20 and the exterior body 12.

  The positive electrode terminal 30 provided on the end side of the sealing plate 20 in the + Y direction is a positive electrode terminal of the secondary battery 10. The positive electrode terminal 30 is electrically insulated from the sealing plate 20 via the resin-made positive electrode side insulating member 32. The positive electrode terminal 30 is inserted into a positive electrode terminal mounting hole provided in the sealing plate 20 and electrically connected to the positive electrode current collector 16. An external conductive member 34 is connected to the positive electrode terminal 30 on the battery external side. The bolt 36 is connected to a position shifted from the position where the positive electrode terminal 30 is connected in the external conductive member 34. Details of the connection between the positive electrode terminal 30 and the positive electrode current collector 16 will be described later.

  The negative electrode terminal 40 provided on the end side of the sealing plate 20 in the -Y direction is a negative electrode terminal in the secondary battery 10. The negative electrode terminal 40 is electrically insulated from the sealing plate 20 via the resin-made negative electrode side insulating member 42. The negative electrode terminal 40 is inserted into the negative electrode terminal mounting hole provided in the sealing plate 20 and is electrically connected to the negative electrode current collector 18. An external conductive member 44 is connected to the negative electrode terminal 40 on the battery external side. The bolt 46 is connected to a position shifted from the position where the negative electrode terminal 40 is connected in the external conductive member 44. Details of the connection between the negative electrode terminal 40 and the negative electrode current collector 18 will be described later.

  Next, the contents of attaching the positive electrode terminal 30 and the negative electrode terminal 40 to the sealing plate 20 will be described in detail with reference to FIGS. 2 to 6.

  First, the connection structure on the positive electrode terminal 30 side will be described using FIGS. 2 and 3, and then the connection structure on the negative electrode terminal 40 side and the like will be described using FIGS. 4 to 7.

  FIG. 2 is a diagram showing the periphery of the positive electrode terminal 30 in the top view of the secondary battery 10. In FIG. 2, the directions of the X-axis and the Y-axis are opposite to those in FIG. 1 so as to be easily compared with the drawings around the negative electrode terminal 40 described later. FIG. 2 shows a sealing plate 20, a positive electrode terminal 30, an insulating member 32 on the positive electrode side, an external conductive member 34 on the positive electrode side, and a bolt 36 on the positive electrode side. FIG. 3 is a cross-sectional view taken along the line AA of FIG. Fig.3 (a) shows the state before the welding process of the positive electrode terminal 30 and the external electrically conductive member 34, (b) shows the state after a welding process.

  In FIG. 3A, the positive electrode terminal mounting hole 50 provided in the sealing plate 20 is a hole into which the positive electrode terminal 30 is inserted. In the sealing plate 20, the recessed portion 21 is provided along the outer peripheral side of the positive electrode terminal mounting hole 50. In the recess 21, a part of the insulating member 32 is disposed. In addition, the recessed part 21 is not an essential structure. Further, the insulating member 32 does not have to be disposed in the recess 21.

  The current collector through hole 52 provided in the positive electrode current collector 16 is a hole into which the positive electrode terminal 30 is inserted. At the time of assembly, the central axes of the two holes of the positive electrode terminal attachment hole 50 and the current collector through hole 52 are aligned with each other.

  Positive electrode terminal 30 includes a flange portion 60 and an annular insertion portion 62 connected to one surface which is a surface on the −Z side of flange portion 60. The flange portion 60 has an outer area larger than the opening area of the positive electrode terminal attachment hole 50, and is a hook-like portion disposed on the outer surface side of the sealing plate 20 in the positive electrode terminal 30. The outer diameter of the flange portion 60 is smaller than the inner diameter of the recess 21 provided in the sealing plate 20. The annular insertion portion 62 is a portion of the positive electrode terminal 30 that is inserted into the positive electrode terminal attachment hole 50 and the current collector through hole 52. The boundary between the flange portion 60 and the annular insertion portion 62 is indicated by an alternate long and short dash line. The same applies to the following figures.

  The protrusion 64 provided on the other surface which is the surface on the + Z side of the flange 60 is a welding end when welding the positive electrode terminal 30 and the external conductive member 34 on the positive electrode side. The protrusions 64 are continuously provided in an annular shape. Instead of this, a plurality of projections 64 arranged in an annular shape may be provided. Alternatively, the upper surface may be in the form of a column having no recess.

  The distal end portion 66 of the insertion portion 62 is expanded in diameter on the positive electrode current collector 16 and caulked on the positive electrode current collector 16. Thereby, the positive electrode terminal 30 and the positive electrode current collector 16 are fixedly connected to the sealing plate 20. Preferably, the crimped tip portion 66 and the positive electrode current collector 16 are further connected by welding. Moreover, the insertion part 62 does not necessarily need to be cyclic | annular, and can also be set as columnar shape which does not have a recessed part.

  The current collector side insulator 54 is an insulating member that electrically insulates between the positive electrode current collector 16 and the sealing plate 20. As shown in FIG. 3A, the current collector side insulator 54 is a positive electrode except for the −Z side surface of the positive electrode current collector 16 on the electrode body 14 side and the inner wall surface of the current collector through hole 52. The outer peripheral surface of the current collector 16 is covered. The current collector side insulator 54 can be made of a resin component. Instead of this, a predetermined outer peripheral surface of the positive electrode current collector 16 may be resin coated.

  The sealing plate side insulator 56 is an insulating member which electrically insulates between the positive electrode terminal mounting hole 50 of the sealing plate 20 and the outer peripheral surface of the positive electrode terminal 30. As shown in FIG. 3A, the sealing plate side insulator 56 is a bottom surface of the recess 21 provided on the outer peripheral side of the positive electrode terminal mounting hole 50 and a surface on the −Z side of the flange portion 60 of the positive electrode terminal 30. It is arranged along the one side and the like. The sealing plate side insulator 56 can be comprised with a resin component. Instead of this, a predetermined outer peripheral surface of the positive electrode terminal 30 may be resin coated.

  The external conductive member 34 on the positive electrode side is a plate member of aluminum-based metal. The positive side bolt 36 is used to fasten a bus bar electrically connecting terminals of adjacent rectangular secondary batteries. A bolt mounting portion is provided at the end on the -Y side of the external conductive member 34 on the positive electrode side to fix the bolt 36, and the end on the + Y side is connected to the positive electrode terminal 30 by welding. Thus, by shifting the positions of the positive electrode terminal 30 and the bolt 36, it is possible to prevent the torque from being directly applied to the positive electrode terminal 30 when fastening the bus bar to the external conductive member 34 with the bolt 36. As a result, it is possible to prevent the reduction in sealing performance between the positive electrode terminal 30 and the sealing plate 20, the damage of the connection portion between the positive electrode terminal 30 and the positive electrode current collector 16, and the like.

  Although the positive electrode terminal 30 is electrically insulated from the sealing plate 20 in the above description, in some cases, the positive electrode terminal 30 and the sealing plate 20 may be electrically connected.

  FIG.3 (b) is a figure which shows the state after welding-processing between the projection part 64 and the external electrically-conductive member 34 from the state of Fig.3 (a). The welding process uses laser welding that emits high energy radiation. Instead of this, welding means such as resistance welding may be used. The nugget 70 is a weld formed by welding between the projection 64 and the external conductive member 34 on the positive electrode side. The formation of the nugget 70 is preferably performed within the height of the projection 64. This can suppress the influence of welding heat on the sealing plate side insulator 56 which is a resin part or the like, and can suppress the thermal deformation and characteristic change of the sealing plate side insulator 56.

  The positive electrode terminal 30 of aluminum-based metal is welded to the external conductive member 34 on the positive electrode side, which is made of aluminum-based metal, at the end on the + Z side. As described above, the welding process on the positive electrode terminal 30 side is performed between the aluminum-based metals, and corrosion due to contact between dissimilar metals does not occur. In addition, since the melting point of aluminum-based metals is relatively low, the heat generated by welding between aluminum-based metals is also relatively small, and aluminum-based metals have lower thermal conductivity than copper-based metals. The influence exerted on the insulating member 32, the current collector side insulator 54 and the sealing plate side insulator 56 is also small.

  FIG. 4 is a diagram showing the periphery of the negative electrode terminal 40 in the top view of the secondary battery 10. The directions of the X axis and the Y axis in FIG. 4 are the same as in FIG. As shown in FIG. 1, the periphery of the positive electrode terminal 30 and the periphery of the negative electrode terminal 40 are laterally symmetrical along the Y axis. Therefore, FIG. 4 is the same as FIG. 2 except that the X-axis and Y-axis directions are reversed. FIG. 4 shows the sealing plate 20, the negative electrode terminal 40, the insulating member 42 on the negative electrode side, the external conductive member 44 on the negative electrode side, and the bolt 46 on the negative electrode side. FIG. 5 is a cross-sectional view taken along the line B-B of FIG. FIG. 5 (a) shows the state before the welding process of the negative electrode terminal 40 and the external conductive member 44, and FIG. 5 (b) shows the state after the welding process.

  When FIG. 5 is compared with FIG. 3, it is the negative electrode terminal 40 that differs from the component on the positive electrode terminal 30 side in the negative electrode terminal 40 side.

  The negative electrode terminal attachment hole 51 has the same content as the positive electrode terminal attachment hole 50, and the current collector through hole 53 provided in the negative electrode current collector 18 is the same as the current collector through hole 52 provided in the positive electrode current collector 16. It is the content. The recess 21 is also the same as the content described on the positive electrode side.

  The current collector side insulator 55 on the negative electrode side has the same content as the current collector side insulator 54 on the positive electrode side. The sealing plate side insulator 57 on the negative electrode side has the same content as the sealing plate side insulator 56 on the positive electrode side.

  The external conductive member 44 on the negative electrode side is a plate member made of an aluminum-based metal, like the external conductive member 34 on the positive electrode side. The negative side bolt 46 has the same content as the positive side bolt 36.

  In addition, in the lower side which is the-Z direction side of bolt 46, portion 43 which sealing plate 20 and insulating member 42 by the side of a negative pole fit mutually is provided. By providing the fitting portion 43, it is possible to suppress that the negative electrode terminal 40 is subjected to torque when the bolt 46 is subjected to a fastening process with another member. Although illustration of this fitting portion is omitted in FIG. 3 on the positive electrode terminal 30 side, the sealing plate 20 and the positive electrode side insulating member 32 are engaged with each other on the lower side of the bolt 36 similarly to the negative electrode terminal 40 side. It is preferable to provide a portion that

  Thus, except for the negative electrode terminal 40, the other elements have the same contents as the corresponding elements on the positive electrode terminal 30 side, and thus further description will be omitted.

  Negative electrode terminal 40 includes a flange portion 80 and an annular insertion portion 82 connected to one surface which is a surface on the −Z side of flange portion 80. The flange portion 80 has an outer area larger than the opening area of the negative electrode terminal attachment hole 51, and is a hook-like portion disposed on the outer surface side of the sealing plate 20 in the negative electrode terminal 40. The outer diameter of the flange portion 80 is smaller than the inner diameter of the recess 21 provided in the sealing plate 20. The annular insertion portion 82 is a portion of the negative electrode terminal 40 to be inserted into the negative electrode terminal attachment hole 51 and the current collector through hole 53. In addition, the recessed part 21 is not an essential structure.

  The negative electrode terminal 40 differs from the positive electrode terminal 30 in the structure of the material surface. The negative electrode terminal 40 has a first region 90 made of a copper-based metal and a second region 92 made of an aluminum-based metal. The surface of the negative electrode terminal 40 may be plated with metal such as nickel. The flange portion 80 has a structure in which a first region 90 and a second region 92 are stacked. The other surface side which is a surface on the + Z side of the flange portion 80 is a second region 92 of aluminum-based metal, and one surface side which is a surface on the -Z side is a first region of copper-based metal. An annular insertion portion 82 is formed by being connected to the first region 90 of the copper-based metal on one surface side of the flange portion 80. The annular insertion portion 82 is formed of a first region 90 of copper-based metal.

FIG. 6 is a view extracting and showing the negative electrode 40. However, it is in the state before caulking the tip portion 86. A boundary C between the first area 90 and the second area 92 is provided on the flange 80. The boundary portion C is a flange portion extending from one surface on the + Z side of the flange portion 80 to the other surface on the −Z side along the Z direction which is the thickness direction of the flange portion 80. It is preferable to be provided in a portion of 50% or less of the thickness t ₀ of 80. In other words, a second region 92 thickness t 5 percent or less in thickness t ₁ of ₀ is an aluminum-based metal of the flange portion 80, the first region 90 of the thickness t ₂ is 5% or more of copper metal It is. Thereby, the boundary C can be set at a position appropriately separated from the projection 84. In addition, along the Z direction which is the thickness direction of the flange portion 80, the boundary portion C is from one surface which is the + Z side surface of the flange portion 80 toward the other surface which is the −Z side surface, It is more preferable to set the thickness t ₀ of the flange portion 80 to 20% or more and 40% or less.

In particular, pay the entire weld nugget 74 in the protruding portion 84, i.e., the weld nugget 74 so as not to reach the flange portion 80, the ratio of the thickness t ₁ to the thickness t ₀ of the flange portion 80 more than 20% 40% It is preferable to set it as the following. With such a configuration, the adverse effect of heat generated when welding the external conductive member 44 and the negative electrode terminal 40 on the sealing plate side insulator 57 is suppressed, and the conductivity of the negative electrode terminal 40 is further improved. It becomes possible.

  FIG. 7 is a view showing some modifications of the shapes of the first region 90 and the second region 92 in the negative electrode 40.

  FIG. 7A shows an example in which the outer diameter of the second region 92 is smaller than the outer diameter of the first region 90 on the outer peripheral side 100 of the flange portion 80, and the first region 90 is the outermost diameter side. That is, the side surface of the second region 92 in the flange portion 80 is covered by the first region 90. Conversely, (b) is an example in which the outer diameter of the second region 92 is made larger than the outer diameter of the first region 90 on the outer peripheral side 101, and the second region 92 is the outermost diameter side. That is, the side surface of the first region 90 in the flange portion 80 is covered by the second region 92. By using these examples, the adhesion between the first region 90 and the second region 92 is improved on the outer peripheral side of the flange portion 80, and the occurrence of damage at the boundary portion C can be suppressed.

  FIG. 7C shows an example in which the first area 90 protrudes to the side of the second area 92 in the central area 102 of the flange portion 80. Conversely, (d) is an example in which the second area 92 protrudes to the side of the first area 90 in the central area 103. By using these examples, the adhesion between the first region 90 and the second region 92 at the center of the flange portion 80 is improved. In (c), since the ratio of the first region 90 having high conductivity can be increased, the electrical resistance of the negative electrode terminal 40 is reduced.

  FIG. 7E is an example in which the diameter of the upper end portion of the insertion portion 82 is expanded in the connection region 104 in which the insertion portion 82 extends from the flange portion 80. Thereby, the electrical resistance in the connection area | region 104 of the flange part 80 and the insertion part 82 is reduced, and mechanical strength improves.

  Referring back to FIG. 5A again, the projection 84 provided on the surface on the + Z side of the flange 80 is a welding end when welding the negative electrode terminal 40 and the external conductive member 44 on the negative electrode side. The protrusions 84 are continuously provided in an annular shape. Instead of this, a plurality of projections 84 arranged in an annular shape may be provided. Or it can also be made columnar shape which does not have a recessed part in an upper surface. The protrusion 84 is a second region 92 made of an aluminum-based metal, and the external conductive member 44 on the negative electrode side is also an aluminum-based metal.

  The distal end portion 86 provided at the −Z side distal end portion of the insertion portion 82 is expanded in diameter on the negative electrode current collector 18 and caulked on the negative electrode current collector 18. The tip portion 86 continuously protrudes in an annular shape with a predetermined thickness. Instead of this, a plurality of annular tip portions 86 may be provided. The tip portion 86 is a first region 90 made of copper-based metal. Preferably, the crimped tip portion 86 and the negative electrode current collector 18 are further connected by welding.

  FIG. 5 (b) is a view showing a state after welding processing of the negative electrode terminal 40 and the external conductive member 44 from the state of FIG. 5 (a). Laser welding is used as the welding process. Instead of this, other welding means such as resistance welding may be used. The nugget 74 is a weld formed by welding between the projection 84 and the external conductive member 44 on the negative electrode side.

  The negative electrode terminal 40 is welded to the external conductive member 44 on the negative electrode side of the aluminum-based metal using the projection 84 of the aluminum-based metal at the end on the + Z side. Thereby, the connection between the negative electrode terminal 40 and the external conductive member 44 on the negative electrode side becomes stronger, and the highly reliable secondary battery 10 is obtained.

  The boundary C between the first region 90 and the second region 92 in the negative electrode terminal 40 is on the + Z side further than the outer surface which is the + Z side surface of the sealing plate 20 and is exposed to the non-aqueous electrolyte There is no Therefore, even if the potential of the negative electrode has a low value, it is possible to reliably prevent the alloying of lithium contained in the aluminum-based metal constituting the second region 92 and the non-aqueous electrolytic solution.

  In addition, since the melting point of the aluminum-based metal is relatively low, the heat generated by welding between the aluminum-based metals is also relatively small. Furthermore, since the aluminum-based metal has lower thermal conductivity than the copper-based metal, it is possible to suppress that the heat generated at the time of welding is transmitted to the negative electrode terminal 40 to adversely affect the sealing plate side insulating member 57 on the negative electrode side. .

  Since the boundary C between the first region 90 and the second region 92 is at a position away from the tip 86 where the crimping process is performed, the application of the stress by the crimping process to the boundary C is suppressed it can.

  Copper-based metals have higher mechanical strength than aluminum-based metals. In the negative electrode terminal 40, the portion (the lower surface of the flange 80, the insertion portion 82, and the tip 86) sandwiching the sealing plate 20 and the negative electrode current collector 18 is made of copper metal. The current collector 18 is fixedly connected to the sealing plate 20 more firmly.

  The sealing plate side insulating member 57 includes a main body portion 57a disposed between the lower surface of the flange portion 80 and the upper surface of the sealing plate 20, and a peripheral wall 57b formed on the peripheral edge portion of the main body portion 57a. And the boundary part C is located below rather than the upper end part of the surrounding wall 57b. Thus, the boundary C is covered by the peripheral wall 57b. According to such a configuration, when moisture is generated in the vicinity of the negative electrode terminal due to condensation or the like, it can be prevented that water droplets or a water film are present across the portion made of copper metal and the portion made of aluminum metal. . Therefore, the corrosion of the portion made of the aluminum-based metal can be suppressed.

  A plurality of the above-described secondary batteries 10 can be connected to configure a battery pack. FIG. 8 is a plan view showing a connection method of two secondary batteries 112 and 114 arranged adjacent to each other in the assembled battery 110. Here, the negative electrode terminal 40 of the secondary battery 112 on one side of the two adjacent secondary batteries 112 and 114 and the positive electrode terminal 30 of the secondary battery 114 on the other side face each other along the X direction. Be placed. In order to connect the negative electrode terminal 40 and the positive electrode terminal 30, the bus bar 116 is used. The bus bar 116 is one of the external conductive members. The bus bar 116 is formed of aluminum-based metal. In other words, the other end portion of the bus bar 116 as an external conductive member whose one end portion is connected by welding to the negative electrode terminal 40 of the secondary battery 112 on one side in the adjacent secondary batteries 112 and 114 is the secondary battery on the other side. It is connected by welding to the positive electrode terminal 30 of 114. By repeating this, the secondary battery 10 can be made into the assembled battery 110 connected in series with a predetermined number determined in advance.

  Although the case where several secondary batteries 10 were mutually connected in series was described in FIG. 8, when mutually connecting several secondary batteries 10 in parallel, each positive electrode terminal of two adjacent secondary batteries 112 and 114 is carried out. 30 are sequentially connected by an external conductive member which is a positive electrode side bus bar, and the negative electrode terminals 40 are sequentially connected by an external conductive member which is a negative electrode side bus bar.

  10, 112, 114 secondary battery, 12 outer package, 14 electrode body, 16 positive electrode current collector, 18 negative electrode current collector, 20 sealing plate, 21 recess, 22 gas discharge valve, 24 sealing plug, 30 positive electrode terminal, 32 (positive electrode side) insulating member, 34 (positive electrode side) external conductive member, 36 (positive electrode side) bolt, 40 negative electrode terminal, 42 (negative electrode side) insulating member, 43 fitting portion, 44 (negative electrode side) external conductive member , 46 (negative electrode side) bolt, 50 positive electrode terminal mounting hole, 51 negative electrode terminal mounting hole, 52 (positive electrode) current collector through hole, 53 (negative electrode) current collector through hole, 54 (positive electrode) current collector side insulator, 55 (negative electrode) current collector side insulator, 56 (positive electrode side) sealing plate side insulator, 57 (negative electrode side) sealing plate side insulator, 60 (positive electrode terminal) flange portion, 62 (of positive electrode terminal) insertion portion, 64 (for positive electrode terminal), 66 (for positive electrode terminal) Of the pole terminal), 70, 74 nugget, 80 (for the negative terminal) flange, 82 (for the negative terminal) insert, 84 (for the negative terminal), projection (for the negative terminal) 86, 90th 1 area, 92 second area, 100, 101 outer peripheral side, 102, 103 central area, 104 connection area, 110 assembled battery, 116 bus bar.

Claims (18)

An electrode body having a positive electrode and a negative electrode;
An exterior body having an opening and housing the electrode body;
A sealing plate for sealing the opening of the exterior body;
A positive electrode terminal attached to the sealing plate and electrically connected to the positive electrode;
A negative electrode terminal inserted into the negative electrode terminal attachment hole provided in the sealing plate via a negative electrode side insulating member and electrically connected to the negative electrode;
Equipped with
The side of the negative terminal is
An anode current collector electrically connecting between the anode and the anode terminal;
An external conductive member connected to the negative electrode terminal and made of an aluminum-based metal;
Is provided,
The negative electrode current collector has a current collector through hole into which the negative electrode terminal is inserted,
The negative terminal is
A flange portion having an outer area larger than the opening area of the negative electrode terminal attachment hole, and an insertion portion connected to one surface of the flange portion disposed on the outer surface side of the sealing plate, the negative electrode terminal And an insertion portion inserted into the mounting hole and the current collector through hole and having a tip end connected to the negative electrode current collector,
A first region composed of a copper-based metal and a second region composed of an aluminum-based metal,
The insertion portion includes the first region, a boundary between the first region and the second region is provided in the flange portion, and the external conductive member is connected by welding to the second region.
The said boundary part is a secondary battery provided in 20 to 40% of the thickness of the said flange part toward the said one surface from the other surface of the said flange part in the thickness direction of the said flange part . The secondary battery according to claim 1, wherein a protrusion is formed on the other surface of the flange.   The secondary battery according to claim 2, wherein the protrusion of the flange and the external conductive member are connected. The secondary battery according to any one of claims 1 to 3 , further comprising a bolt portion connected to the negative electrode terminal through the external conductive member. The negative electrode side insulating member has a main body portion disposed between the flange portion and the sealing plate, and a peripheral wall provided on a peripheral portion of the main body portion.
The secondary battery according to any one of claims 1 to 4 , wherein the boundary portion is disposed below an upper end of the peripheral wall. A constructed battery pack by connecting a plurality of secondary batteries of any crab claimed in claim 1 3, 5,
An assembled battery in which the negative electrode terminal of the secondary battery on one side of the adjacent secondary battery and the positive electrode terminal of the secondary battery on the other side are connected by the external conductive member. An electrode body having a positive electrode and a negative electrode;
An exterior body having an opening and housing the electrode body;
A sealing plate for sealing the opening of the exterior body;
A positive electrode terminal attached to the sealing plate and electrically connected to the positive electrode;
A negative electrode terminal inserted into the negative electrode terminal attachment hole provided in the sealing plate via a negative electrode side insulating member and electrically connected to the negative electrode;
Equipped with
The side of the negative terminal is
An anode current collector electrically connecting between the anode and the anode terminal;
An external conductive member connected to the negative electrode terminal and made of an aluminum-based metal;
Is provided,
The negative electrode current collector has a current collector through hole into which the negative electrode terminal is inserted,
The negative terminal is
A flange portion having an outer area larger than the opening area of the negative electrode terminal attachment hole, and an insertion portion connected to one surface of the flange portion disposed on the outer surface side of the sealing plate, the negative electrode terminal And an insertion portion inserted into the mounting hole and the current collector through hole and having a tip end connected to the negative electrode current collector,
A first region composed of a copper-based metal and a second region composed of an aluminum-based metal,
The insertion portion includes the first region, a boundary between the first region and the second region is provided in the flange portion, and the external conductive member is connected by welding to the second region.
The negative electrode side insulating member has a main body portion disposed between the one surface of the flange portion and an outer surface of the sealing plate, and a peripheral wall provided on a peripheral portion of the main body portion.
The peripheral wall faces the side surface of the flange portion,
The said boundary part is a secondary battery arrange | positioned downward rather than the upper end of the said surrounding wall. The secondary battery according to claim 7, wherein the external conductive member is disposed on the other surface of the flange portion. The secondary battery according to claim 7, wherein an end of the boundary portion is located on a side surface of the flange portion. In the central region in the radial direction of the negative electrode terminal, the boundary portion is formed such that one of the first region and the second region protrudes to the other side of the first region and the second region. The secondary battery as described in. The end of the boundary is located on the one side of the flange,
9. The secondary battery according to claim 8, wherein a central region of the boundary portion is positioned closer to the other surface of the flange portion than the one surface of the flange portion in the thickness direction of the flange portion. An assembled battery comprising a plurality of secondary batteries according to any one of claims 7 to 11. An electrode body having a positive electrode and a negative electrode;
An exterior body having an opening and housing the electrode body;
A sealing plate for sealing the opening of the exterior body;
A positive electrode terminal attached to the sealing plate and electrically connected to the positive electrode;
A negative electrode terminal inserted into the negative electrode terminal attachment hole provided in the sealing plate via a negative electrode side insulating member and electrically connected to the negative electrode;
Equipped with
The side of the negative terminal is
An anode current collector electrically connecting between the anode and the anode terminal;
An external conductive member connected to the negative electrode terminal and made of an aluminum-based metal;
Is provided,
The negative electrode current collector has a current collector through hole into which the negative electrode terminal is inserted,
The negative terminal is
A flange portion having an outer area larger than the opening area of the negative electrode terminal attachment hole, and an insertion portion connected to one surface of the flange portion disposed on the outer surface side of the sealing plate, the negative electrode terminal And an insertion portion inserted into the mounting hole and the current collector through hole and having a tip end connected to the negative electrode current collector,
A first region composed of a copper-based metal and a second region composed of an aluminum-based metal,
The insertion portion includes the first region, a boundary between the first region and the second region is provided in the flange portion, and the external conductive member is connected by welding to the second region.
In the central region of the negative electrode terminal in the radial direction, the boundary is formed such that one of the first region and the second region protrudes to the other side of the first region and the second region. battery. The secondary battery according to claim 13, wherein an end of the boundary portion is located on a side surface of the flange portion. An assembled battery comprising a plurality of secondary batteries according to claim 13 or 14. An electrode body having a positive electrode and a negative electrode;
An exterior body having an opening and housing the electrode body;
A sealing plate for sealing the opening of the exterior body;
A positive electrode terminal attached to the sealing plate and electrically connected to the positive electrode;
A negative electrode terminal inserted into the negative electrode terminal attachment hole provided in the sealing plate via a negative electrode side insulating member and electrically connected to the negative electrode;
Equipped with
The side of the negative terminal is
An anode current collector electrically connecting between the anode and the anode terminal;
An external conductive member connected to the negative electrode terminal and made of an aluminum-based metal;
Is provided,
The negative electrode current collector has a current collector through hole into which the negative electrode terminal is inserted,
The negative terminal is
A flange portion having an outer area larger than the opening area of the negative electrode terminal attachment hole, and an insertion portion connected to one surface of the flange portion disposed on the outer surface side of the sealing plate, the negative electrode terminal And an insertion portion inserted into the mounting hole and the current collector through hole and having a tip end connected to the negative electrode current collector,
A first region composed of a copper-based metal and a second region composed of an aluminum-based metal,
The insertion portion includes the first region, a boundary between the first region and the second region is provided in the flange portion, and the external conductive member is connected by welding to the second region.
The secondary battery in which one side face of the first area and the second area in the flange portion is covered with the other of the first area and the second area . The side surface of the first area in the flange portion is covered with the second area,
The secondary battery according to claim 16, wherein an end of the boundary portion is located on the one surface of the flange portion. An assembled battery comprising a plurality of secondary batteries according to claim 16 or 17.

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