JP5795937B2 - Secondary battery - Google Patents

Description

  The present invention relates to a secondary battery.

  In recent years, secondary batteries with large capacity (Wh) have been developed as power sources for hybrid electric vehicles and pure electric vehicles. Among them, prismatic lithium ion secondary batteries with high energy density (Wh / kg) are of particular interest. Has been.

  In a rectangular lithium ion secondary battery, a flat wound electrode group is formed by winding a positive electrode and a negative electrode with a separator interposed therebetween. The wound electrode group is electrically connected to a positive electrode terminal and a negative electrode terminal attached to the through hole of the battery lid via an insulating seal member. The wound electrode group is accommodated in a battery can of the battery container, and the opening of the battery can is sealed and welded with a battery lid. The secondary battery is formed by injecting an electrolytic solution from a liquid injection hole of a battery container containing a wound electrode group, inserting a liquid injection stopper, and sealing and welding by laser welding.

  An assembled battery is formed by electrically connecting the positive electrode terminals and the negative electrode terminals of the plurality of square secondary batteries (single cells) with a conductive member such as a bus bar. Patent Document 1 describes a secondary battery including a disk-shaped external terminal suitable for welding a bus bar.

JP 2005-142026 A

  However, when the assembled battery is formed by connecting a plurality of secondary batteries (single cells) described in Patent Document 1, the terminal rotates due to vibration or impact acting on the assembled battery, and the terminal and the through hole of the battery lid There is a risk that the airtightness of the battery container may be impaired due to deformation, damage, or displacement of the insulating seal member interposed between the two.

The invention according to claim 1 is a wound electrode group in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, a battery can that houses the wound electrode group, a battery lid that seals the battery can, and a battery A positive electrode terminal and a negative electrode terminal attached to each of a pair of through holes provided in the lid; and each of the positive electrode terminal and the negative electrode terminal and the battery lid interposed between the positive electrode terminal and the negative electrode terminal and the through hole. A positive electrode current collector having an insulating seal member that insulates the electrode, an electrode connection portion connected to the positive electrode, a terminal connection portion fixed to the positive electrode terminal, an electrode connection portion connected to the negative electrode, and a negative electrode A negative electrode current collector having a terminal connection portion fixed to the terminal; and each of the positive electrode and negative electrode current collector terminals interposed between the battery cover and each of the positive and negative electrode current collectors; An insulating member that insulates the battery lid, The insulating member has a convex portion protruding toward the inside of the pond can, and the insulating member has a first concave portion into which the terminal connecting portion of the positive and negative electrode current collector is fitted and a second concave portion into which the convex portion of the battery lid is fitted. And when the rotational force about the positive and negative electrode terminals acts on the positive and negative electrode terminals, the side surfaces of the first concave portion of the insulating member are connected to the positive and negative electrode terminals via the side surfaces of the terminal connecting portion fixed to the positive and negative electrode terminals. receiving the rotational force from, that side of the convex portion of the battery lid is subjected to rotational force from the insulating member through the side surface of the second recess of the insulating member, rotating with respect to the battery cover of the positive and negative terminals can be prevented, the battery A battery container composed of a can and a battery lid is formed into a square shape having a pair of wide surfaces and a pair of narrow surfaces, and the terminal connecting portion is a rectangular flat plate, and is formed on the narrow surface of the battery can. an inner side and an outer side surface disposed in parallel, a pair of wide surface side surface which is positioned parallel to the wide surface of the battery can Has, disposed along the inner surface of the battery lid, the first recess of the insulating member comprises an outer engagement for engaging the outer side of the inner engaging surface and the terminal connecting portion engaged with the inner side surface of the terminal connecting portion Although it has a surface, it is a secondary battery characterized by not having the engagement surface engaged with each of a pair of wide surface side surface of a terminal connection part .
According to a second aspect of the present invention, in the secondary battery according to the first aspect, the terminal connection portion is further provided with an auxiliary engagement portion protruding from the inner side surface toward the center side of the battery can, The first recess is further provided with an auxiliary engagement surface that engages with a side surface of the auxiliary engagement portion.
According to a third aspect of the present invention, in the secondary battery according to the first or second aspect, the insulating member is provided with a position restricting portion having a surface in contact with the wound electrode group, and the second of the insulating member. The recess is provided corresponding to the position restricting portion.

According to the present invention, it is possible to prevent the positive and negative electrode terminals from rotating due to vibration or impact acting on the secondary battery.

The perspective view of the assembled battery comprised by the single battery which concerns on the 1st Embodiment of this invention. The perspective view which shows the external appearance of the cell which concerns on the 1st Embodiment of this invention. The disassembled perspective view which shows the structure of the single battery of FIG. FIG. 4 is a perspective view showing the wound electrode group of FIG. 3. (A) is a perspective view which shows the battery cover assembly of FIG. 3, (b) is a disassembled perspective view of a battery cover assembly. FIG. 6 is a perspective view showing the insulating member of FIG. 5. (A) is the VII-VII sectional view taken on the line of FIG. 5, (b) is the AA sectional view taken on the line of FIG. 7 (a). The conceptual diagram which shows the state which the vibration acted on the assembled battery. The schematic diagram which shows the engagement state of the negative electrode electrical power collector connected to the negative electrode terminal, and an insulating member. (A) is a perspective view which shows the battery cover assembly of the cell concerning the 2nd Embodiment of this invention, (b) is a disassembled perspective view of a battery cover assembly. The perspective view which shows the insulating member of FIG. The schematic diagram which shows the engagement state of the negative electrode electrical power collector connected to the negative electrode terminal, and an insulating member.

Hereinafter, with reference to the drawings, an embodiment in which the present invention is applied to a rectangular lithium ion secondary battery (hereinafter referred to as a single battery) constituting an assembled battery mounted on a hybrid electric vehicle or a pure electric vehicle will be described. explain.
-First embodiment-
FIG. 1 is a perspective view of an assembled battery. As shown in FIG. 1, the assembled battery includes a plurality of unit cells 100A to 100C. The cells 100A to 100C have a flat rectangular parallelepiped shape, and are arranged side by side so that the wide surfaces 101a having a large area among the side surfaces face each other. As illustrated, the single cells 100A and 100C have a positive electrode terminal 141 disposed on the left side in the drawing, and the single cell 100B has a negative electrode terminal 151 disposed on the left side in the drawing. That is, the plurality of unit cells 100A to 100C arranged side by side are reversed in direction so that the positions of the positive electrode terminal 141 and the negative electrode terminal 151 attached to the battery cover 102 of each of the unit cells 100A to 100C are reversed. Has been placed.

  As shown in FIG. 1, the positive electrode terminal 141 on the left side of the unit cell 100 </ b> A and the negative electrode terminal 151 on the left side of the unit cell 100 </ b> B are electrically connected by a bus bar 110 that is a metal plate-like conductive member. ing. Similarly, the positive electrode terminal 141 on the right side of the cell 100B in the drawing and the negative electrode terminal 151 on the right side of the cell 100C in the drawing are electrically connected by the bus bar 110. The bus bar 110 that electrically connects the cells is connected to the positive terminal 141 and the negative terminal 151 by laser welding.

  A negative electrode terminal 151 on the right side of the cell 100A shown in FIG. 1 and a positive electrode terminal 141 on the left side of the cell 100C in FIG. 1 are electrically conductive members (not shown) electrically connected in series or in parallel to other batteries (not shown). Or is connected to a power extraction terminal (not shown) by a conductive member (not shown).

  A single battery constituting the assembled battery will be described. Since each of the unit cells 100A to 100C has the same structure, the unit cell 100A will be described below as a representative. FIG. 2 is an external perspective view showing the unit cell 100A, and FIG. 3 is an exploded perspective view showing the configuration of the unit cell 100A. 4 is a perspective view showing the wound electrode group 170, and FIG. 5 is a perspective view showing the battery lid assembly 107.

  As shown in FIG. 2, the unit cell 100 </ b> A includes a battery container including a battery can 101 and a battery lid 102. The material of the battery can 101 and the battery lid 102 is aluminum or an aluminum alloy. As shown in FIG. 3, the wound electrode group 170 is accommodated in the battery can 101. The battery can 101 has a pair of wide surfaces 101a, a pair of narrow surfaces 101b, and a bottom surface 101c, and is formed in a rectangular box shape with an upper surface opened. The wound electrode group 170 is accommodated in the battery can 101 while being covered with the insulating case 108. The material of the insulating case 108 is an insulating resin such as polypropylene. Thereby, the inner surface of the battery can 101 and the wound electrode group 170 are electrically insulated.

  As shown in FIGS. 2 and 3, the battery lid 102 has a rectangular flat plate shape and is welded so as to close the opening of the battery can 101. That is, the battery lid 102 seals the battery can 101. The battery lid 102 has a positive electrode terminal 141 and a negative electrode terminal 151 electrically connected to the positive electrode 174 and the negative electrode 175 of the wound electrode group 170 via the positive electrode current collector 180 and the negative electrode current collector 190, respectively. It is arranged.

  The positive electrode terminal 141 is electrically connected to the positive electrode 174 of the wound electrode group 170 via the positive electrode current collector 180, and the negative electrode terminal 151 is connected to the negative electrode 175 of the wound electrode group 170 via the negative electrode current collector 190. Since it is electrically connected, power is supplied to the external load via the positive electrode terminal 141 and the negative electrode terminal 151, or external generated power is supplied to the wound electrode group 170 via the positive electrode terminal 141 and the negative electrode terminal 151. And charged.

As shown in FIG. 3, the battery lid 102 is provided with a liquid injection hole 106a for injecting an electrolytic solution into the battery container. The liquid injection hole 106a is sealed by a liquid injection plug 106b after the electrolytic solution is injected. As the electrolytic solution, for example, a non-aqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a carbonate-based organic solvent such as ethylene carbonate can be used.

  As shown in FIG. 2, the battery cover 102 is provided with a gas discharge valve 103. The gas discharge valve 103 is formed by partially thinning the battery lid 102 by press working. The gas discharge valve 103 is formed with a cleavage groove so that a large opening is formed at the time of cleavage. The gas discharge valve 103 generates heat due to abnormalities such as overcharging of the unit cell, generates gas, and when the pressure in the battery container rises and reaches a predetermined pressure, the gas discharge valve 103 is opened and discharges the gas from the inside. To reduce the pressure in the battery container.

  The wound electrode group 170 will be described with reference to FIG. FIG. 4 is a perspective view showing the wound electrode group 170. As shown in FIG. 4, the wound electrode group 170 that is a power storage element is obtained by winding a long positive electrode 174 and a negative electrode 175 in a flat shape around a winding axis W with a separator 173 interposed therebetween. It is a laminated structure.

  The positive electrode 174 includes a positive electrode foil 171 and a positive electrode active material mixture layer 176 formed by coating a positive electrode active material mixture in which a binder (binder) is mixed with a positive electrode active material on both surfaces of the positive electrode foil 171. Have The negative electrode 175 includes a negative electrode foil 172 and a negative electrode active material mixture layer 177 formed by coating a negative electrode active material mixture in which a binder (binder) is mixed with a negative electrode active material on both surfaces of the negative electrode foil 172. Have Charging / discharging is performed between the positive electrode active material and the negative electrode active material.

  The positive foil 171 is an aluminum alloy foil having a thickness of about 20 to 30 μm, and the negative foil 172 is a copper alloy foil having a thickness of about 15 to 20 μm. The material of the separator 173 is a porous polyethylene resin. The positive electrode active material is a lithium-containing transition metal double oxide such as lithium manganate, and the negative electrode active material is a carbon material such as graphite capable of reversibly occluding and releasing lithium ions.

  One end of both ends of the wound electrode group 170 in the width direction (winding axis W direction orthogonal to the winding direction) is an uncoated portion where the positive electrode active material mixture layer 176 is not formed (exposure of the positive electrode foil 171). Part) is a part where the negative electrode active material mixture layer 177 is not formed, and the other part is a part where the uncoated part (exposed part of the negative electrode foil 172) is laminated. The laminated body of the positive electrode side uncoated part and the laminated body of the negative electrode side uncoated part are respectively crushed in advance, and are respectively positive electrode current collector 180 and negative electrode current collector 190 (see FIG. 5) of battery lid assembly 107 described later. (See (a)) and ultrasonic bonding.

  5A is a perspective view of the battery lid assembly 107, and FIG. 5B is an exploded perspective view of the battery lid assembly 107. FIG. Although FIG. 5 shows the configuration on the negative electrode side, the negative electrode side and the positive electrode side have the same shape and configuration, and therefore, for convenience, reference numerals of components on the positive electrode side are given in parentheses. In FIG. 5B, the negative electrode terminal 151 and the gasket 130 are not shown.

  The battery lid assembly 107 includes a battery lid 102, a negative electrode terminal 151 and a positive electrode terminal 141 attached to each of a pair of through holes 102h provided in the battery lid 102, a negative electrode current collector 190, and a positive electrode current collector 180. And a pair of gaskets 130 and a pair of insulating members 160.

  The material of the negative electrode terminal 151 and the negative electrode current collector 190 is a copper alloy. The negative electrode terminal 151 is electrically connected to the negative electrode current collector 190. The material of the positive electrode terminal 141 and the positive electrode current collector 180 is an aluminum alloy. The positive electrode terminal 141 is electrically connected to the positive electrode current collector 180. The material of the insulating member 160 is an insulating material in which glass fiber (GF) is mixed with “hard plastic” defined in JIS K6900 plastics. The material of the gasket 130 is an insulating resin such as polybutylene terephthalate, polyphenylene sulfide, perfluoroalkoxy fluororesin.

  As shown in FIG. 3 and FIG. 5B, the battery lid 102 is provided with a pair of circular through holes 102 h and a pair of circular protrusions 102 c that protrude toward the inside of the battery can 101. . As will be described later, the through-holes 143 and 153 of the positive and negative electrode terminals 141 and 151 are inserted into the through-hole 102h via the gasket 130 (see FIG. 3) (see FIG. 7A). The circular convex portion 102c is fitted into the circular concave portion 167 of the insulating member 160 as described later (see FIG. 7A). The circular convex portion 102 c is formed into a bottomed cylindrical shape by being pressed from the outer surface of the battery lid 102 toward the inside.

  As shown in FIG. 5B, the negative electrode current collector 190 includes a rectangular flat plate-shaped terminal connection portion 191 disposed along the inner surface of the battery lid 102 and a substantially right angle from one side of the terminal connection portion 191. A flat plate 192 that is bent and extends toward the bottom surface 101c of the battery can 101 along the wide surface 101a of the battery can 101, and a joint portion 193 connected by a connecting portion 196 provided at the lower end of the flat plate 192. I have. The bonding portion 193 is a portion that is electrically connected to the negative electrode 175 of the wound electrode group 170 by ultrasonic bonding, and has a bonding surface 193 a with the negative electrode 175. The terminal connection portion 191 is provided with a circular through hole 194 into which a protrusion 155 (see FIG. 3) of a negative electrode terminal 151 described later is inserted. As shown in FIG. 5A, the negative terminal 151 is fixed to the terminal connecting portion 191 by caulking and welding.

  Similarly, as shown in FIG. 5B, the positive electrode current collector 180 includes a rectangular flat terminal connection portion 181 disposed along the inner surface of the battery lid 102, and one side of the terminal connection portion 181. A flat plate 182 that is bent substantially at a right angle and extends toward the bottom surface 101c of the battery can 101 along the wide surface 101a of the battery can 101, and a joint portion connected by a connecting portion 186 provided at the lower end of the flat plate 182 183. The joint portion 183 is a portion that is electrically connected to the positive electrode 174 of the wound electrode group 170 by ultrasonic bonding, and has a joint surface 183 a with the positive electrode 174. The terminal connection portion 181 is provided with a circular through hole 184 into which a protrusion 145 (see FIG. 3) of the positive electrode terminal 141 described later is inserted. As shown in FIG. 5A, the positive terminal 141 is fixed to the terminal connecting portion 181 by caulking and welding.

  As shown in FIG. 5A, the terminal connection portion 191 of the negative electrode current collector 190 is fitted in the recess 162 of the insulating member 160 (see FIG. 5B). The inner side surface 191 i and the outer side surface 191 o of the terminal connection portion 191 are arranged in parallel to the narrow surface 101 b of the battery can 101. As will be described later, the inner side surface 191i of the terminal connection portion 191 is abutted against the inner engagement surface 162i (see FIG. 5B) of the recess 162 of the insulating member 160, and the outer side surface 191o of the terminal connection portion 191 is The insulating member 160 is in contact with the outer engagement surface 162o (see FIG. 5B) of the recess 162.

  Similarly, as shown in FIG. 5A, the terminal connection portion 181 of the positive electrode current collector 180 is fitted in the recess 162 (see FIG. 5B) of the insulating member 160. The inner side surface 181 i and the outer side surface 181 o of the terminal connection portion 181 are arranged in parallel to the narrow surface 101 b of the battery can 101. As will be described later, the inner side surface 181i of the terminal connection portion 181 is brought into contact with the inner engagement surface 162i (see FIG. 5B) of the recess 162 of the insulating member 160, and the outer side surface 181o of the terminal connection portion 181 is The insulating member 160 is in contact with the outer engagement surface 162o (see FIG. 5B) of the recess 162.

  As shown in FIG. 5, an insulating member 160 is disposed between the terminal connecting portions 181 and 191 of the positive and negative electrode current collectors 180 and 190 and the battery lid 102. FIG. 6 is a perspective view of the insulating member 160. 7A is a sectional view taken along line VII-VII in FIG. 5, and FIG. 7B is a sectional view taken along line AA in FIG. 7A. Although FIG. 7 shows the configuration on the negative electrode side, since the negative electrode side and the positive electrode side have the same shape and configuration, the reference numerals of the components on the positive electrode side are given in parentheses for convenience. In FIG. 7A, the wound electrode group 170 and the bus bar 110 are illustrated by a two-dot chain line.

  As shown in FIGS. 6 and 7, the insulating member 160 is a substantially flat plate-like member, the long side is arranged in parallel to the wide surface 101 a of the battery can 101, and the short side is the narrow surface 101 b of the battery can 101. (See FIG. 5).

  As shown in FIGS. 5A and 7, the insulating member 160 includes a base portion 161 interposed between each of the terminal connection portions 181 and 191 of the positive and negative current collectors 180 and 190 and the battery lid 102. And a thick part 165 extending from the base part 161.

  As shown in FIG. 6B, the surface of the insulating member 160 on the battery lid 102 side is a contact surface 160 a that contacts the battery lid 102. As shown in FIG. 6A, the surface of the base portion 161 on the wound electrode group 170 side is a contact surface 162 a that contacts the terminal connection portions 181 and 191. As shown in FIGS. 5A and 7, the base portion 161 of the insulating member 160 having insulating properties is provided between the terminal connection portions 181 and 191 of the positive and negative current collectors 180 and 190 and the battery lid 102. Therefore, each of the positive and negative electrode current collectors 180 and 190 and the battery lid 102 are electrically insulated from each other.

  The thickness of the thick portion 165 is formed to be thicker than the thickness of the base portion 161, and in this embodiment, the thickness corresponds to the sum of the thickness of the base portion 161 and the thicknesses of the terminal connection portions 181 and 191. ing. A step is provided between the base portion 161 and the thick portion 165.

  As shown in FIGS. 6 and 7, the insulating member 160 has an engagement wall 164 formed so as to protrude from one end portion of the base portion 161 toward the wound electrode group 170, and a thick portion 165. And a position restricting portion 166 formed so as to protrude toward the rotating electrode group 170.

  The engagement wall 164 has a rectangular parallelepiped shape and is provided in parallel to the narrow surface 101 b of the battery can 101. The position restricting portion 166 has a rectangular parallelepiped shape, and has a position restricting surface 166 a having a rectangular shape in a plan view and in contact with the wound electrode group 170. As shown in FIG. 7A, the wound electrode group 170 is ultrasonically bonded to the positive and negative electrode current collectors 180 and 190 while being in surface contact with the position regulating surface 166a.

  As shown in FIGS. 6 and 7, the insulating member 160 has a recess 162 into which the terminal connection portions 181 and 191 of the positive and negative current collectors 180 and 190 are fitted. The recess 162 is formed by the base portion 161, the engagement wall 164, and the thick portion 165 described above. The concave portion 162 is provided at a step portion between the contact surface 162 a of the base portion 161, one side surface of the engagement wall 164 (hereinafter referred to as an outer engagement surface) 162 o, and the thick portion 165 and the base portion 161. One side surface (hereinafter referred to as an inner engagement surface) 162i of the thick portion 165.

  The inner engagement surface 162 i and the outer engagement surface 162 o are respectively disposed in parallel to the narrow surface 101 b of the battery can 101. When the terminal connection portions 181 and 191 are fitted in the recess 162 of the insulating member 160, as shown in FIGS. 5, 7A, and 7B, the terminal connection portions 181 and 181 are connected to the inner engagement surface 162i. The inner side surfaces 181i and 191i of 191 are in contact with each other, and the outer side surfaces 181o and 191o of the terminal connection portions 181 and 191 are in contact with the outer engagement surface 162o.

  As shown in FIG. 6, the base portion 161 of the insulating member 160 has circular through holes 161 h into which through portions 143 and 153 (see FIG. 7A) of positive and negative terminal 141 and 151 described later are inserted. Is provided. As shown in FIG. 6B, the thick portion 165 is provided with a circular recess 167 at the position facing the circular protrusion 102c of the battery lid 102 so that the battery lid 102 side is open. The circular recess 167 has a circular bottom surface in plan view and an inner peripheral surface that rises perpendicularly from the bottom surface. As shown in FIG. 7A, the circular recess 167 is provided corresponding to the position restricting portion 166 extending from the thick portion 165 toward the wound electrode group 170 side.

  As shown in FIGS. 7A and 7B, the circular convex portion 102 c of the battery lid 102 is fitted into the circular concave portion 167 of the insulating member 160. When the circular convex portion 102 c is fitted into the circular concave portion 167, the outer peripheral surface of the circular convex portion 102 c comes into contact with the inner peripheral surface of the circular concave portion 167.

  As shown in FIG. 3, the negative electrode terminal 151 includes a cylindrical external terminal portion 152, a cylindrical through portion 153 that penetrates the through hole 102 h of the battery lid 102 and the through hole 161 h of the insulating member 160, and a through hole And a cylindrical protrusion 155 that protrudes from one end of the portion 153 toward the wound electrode group 170 side. The outer diameter size of the through portion 153 is smaller than the outer diameter size of the external terminal portion 152, and the outer diameter size of the protrusion 155 is smaller than the outer diameter size of the through portion 153.

  As shown in FIG. 7A, the top surface of the external terminal portion 152 is a bus bar welding surface 152a to which the bus bar 110 is welded. The bus bar 110 is laser-welded while being in contact with the bus bar welding surface 152a. The through portion 153 of the negative electrode terminal 151 is inserted into the through hole 102h of the battery lid 102 with the gasket 130 attached.

  Similarly, as shown in FIG. 3, the positive electrode terminal 141 includes a cylindrical external terminal portion 142, and a cylindrical through portion 143 that penetrates the through hole 102 h of the battery lid 102 and the through hole 161 h of the insulating member 160. And a cylindrical projection 145 projecting from one end of the through-portion 143 toward the wound electrode group 170 side. The outer diameter size of the through portion 143 is smaller than the outer diameter size of the external terminal portion 142, and the outer diameter size of the protrusion 145 is smaller than the outer diameter size of the through portion 143.

  As shown in FIG. 7A, the top surface of the external terminal 142 is a bus bar welding surface 142a to which the bus bar 110 is welded. The bus bar 110 is laser-welded while being in contact with the bus bar welding surface 142a. The through portion 143 of the positive terminal 141 is inserted into the through hole 102h of the battery lid 102 with the gasket 130 attached.

  As shown in FIG. 7A, the gasket 130 includes a cylindrical small-diameter cylindrical portion 130a, an annular flange 130b extending outward from the upper end of the small-diameter cylindrical portion 130a, and an outer edge of the flange 130b. And a cylindrical large-diameter cylindrical portion 130c that rises upward.

  The small-diameter cylindrical portion 130 a of the gasket 130 is disposed so as to be interposed between the through portions 143 and 153 of the positive and negative electrode terminals 141 and 151 and the through hole 102 h of the battery lid 102. The flange portion 130 b of the gasket 130 is disposed so as to be interposed between the outer surface of the battery lid 102 and the end surfaces of the external terminal portions 142 and 152 of the positive and negative electrode terminals 141 and 151. Thereby, between each of the positive / negative terminal 141,151 and the battery cover 102 is sealed, and the airtightness of the battery container is ensured. Since the gasket 130 has an insulating property as described above, each of the positive and negative electrode terminals 141 and 151 and the battery cover 102 are electrically insulated.

  The large-diameter cylindrical portion 130c of the gasket 130 is in close contact with the external terminal portions 142 and 152 so as to cover the lower outer surfaces of the external terminal portions 142 and 152 of the positive and negative terminals 141 and 151. Thereby, even if water droplets adhere to the battery lid 102 due to condensation or the like, it is possible to ensure insulation between the positive and negative electrode terminals 141 and 151 and the battery lid 102.

  The cylindrical protrusion 155 of the negative electrode terminal 151 is inserted through a through hole 194 formed in the terminal connection portion 191 of the negative electrode current collector 190. A cylindrical protrusion with the flange 130b of the gasket 130 sandwiched between the lower end surface of the external terminal portion 152 and the outer surface of the battery lid 102 and the lower end surface of the through portion 153 in contact with the terminal connection portion 191. The tip of 155 is caulked to the terminal connection portion 191 of the negative electrode current collector 190.

  As a result, as shown in FIG. 7A, the terminal connection portion 191 of the negative electrode current collector 190 is sandwiched between the crimping portion 155s and the lower end surface of the through portion 153, and the insulating member 160, the battery lid 102, and the gasket 130 The part 130 b is sandwiched between the terminal connection part 191 and the lower end surface of the external terminal part 152. The caulking portion 155s and the terminal connecting portion 191 are spot-welded by a laser after being caulked and fixed.

  Similarly, the cylindrical protrusion 145 of the positive electrode terminal 141 is inserted into a through hole 184 formed in the terminal connection portion 181 of the positive electrode current collector 180. A cylindrical protrusion with the flange 130b of the gasket 130 sandwiched between the lower end surface of the external terminal portion 142 and the outer surface of the battery lid 102, and the lower end surface of the through portion 143 being in contact with the terminal connection portion 181. The tip of 145 is caulked to the terminal connection portion 181 of the positive electrode current collector 180.

  As a result, as shown in FIG. 7A, the terminal connection portion 181 of the positive electrode current collector 180 is sandwiched between the crimping portion 145s and the lower end surface of the through portion 143, and the insulating member 160, the battery lid 102, and the gasket 130 The part 130 b is sandwiched between the terminal connection part 181 and the lower end surface of the external terminal part 142. The caulking portion 145s and the terminal connection portion 181 are spot-welded by laser after being caulked and fixed.

  Thus, the positive electrode terminal 141 is fixed to the terminal connection part 181 of the positive electrode current collector 180 by caulking and welding, and the negative electrode terminal 151 is fixed to the terminal connection part 191 of the negative electrode current collector 190 by caulking and welding. Yes. Thereby, the positive electrode current collector 180 and the positive electrode terminal 141 are electrically connected, and the negative electrode current collector 190 and the negative electrode terminal 151 are electrically connected.

  FIG. 8 is a conceptual diagram illustrating a state in which vibration is applied to the assembled battery, and FIG. 9 is a schematic diagram illustrating an engagement state between the negative electrode current collector 190 connected to the negative electrode terminal 151 and the insulating member 160. . Although FIG. 9 shows the configuration on the negative electrode side, since the negative electrode side and the positive electrode side have the same shape and configuration, the reference numerals of the components on the positive electrode side are given in parentheses for convenience.

  When vibration in the longitudinal direction of the battery lid 102 acts on the assembled battery, as shown by arrows in FIG. 8, the unit cell 100A and the unit cell 100B are displaced from each other so as to move in opposite directions, and the unit cell 100A and A rotational torque about the central axis of the positive and negative terminals 141 and 151 acts on the positive and negative terminals 141 and 151 to which the bus bar 110 connecting the unit cell 100B is welded.

  Similarly, the unit cell 100B and the unit cell 100C are displaced so that they move in opposite directions, and the positive and negative terminals 141 and 151 to which the bus bar 110 connecting the unit cell 100B and the unit cell 100C is welded are positive and negative. A rotational torque about the center axis of the pole terminals 141 and 151 acts.

  As shown in FIG. 9, when a rotational torque about the central axis CL of the positive / negative terminal 141, 151 acts on the positive / negative terminal 141, 151, the side surface of the recess 162 of the insulating member 160 becomes the terminal connection 181, The terminal connection portions 181 and 191 fixed to the positive and negative terminals 141 and 151 are prevented from rotating by receiving a force from the side surface of the 191.

  For example, when rotational torque acts in the direction of the arrow T1 shown in FIG. 9, the insulating member 160 receives forces from the terminal connecting portions 181 and 191 mainly at the engaging portion E11 and the engaging portion E12 shown in FIG. . Although the insulating member 160 is a resin material having lower rigidity than the terminal connection portions 181 and 191, as shown in FIG. 9, the insulation member 160 receives the force from the terminal connection portions 181 and 191 mainly at two locations. Compared with the case where the force from the terminal connection portions 181 and 191 is received at the place, the force acting on the insulating member 160 can be dispersed and the deformation of the insulating member 160 can be suppressed.

According to this embodiment described above, the following operational effects can be achieved.
(1) The concave portion 162 fitted to the terminal connecting portions 181 and 191 of the positive and negative current collectors 180 and 190 to which the positive and negative electrode terminals 141 and 151 are fixed is provided in the insulating member 160, and the circular convex portion of the battery lid 102 A circular recess 167 fitted to 102 c is provided in the insulating member 160. As a result, when a rotational force about the center axis CL (see FIG. 9) of the positive and negative terminals 141 and 151 acts on the positive and negative terminals 141 and 151, FIG. 7A, FIG. 7B and FIG. As shown, the side surface of the concave portion 162 of the insulating member 160 receives the rotational force from the positive and negative electrode terminals 141 and 151 via the side surfaces of the terminal connection portions 181 and 191 fixed to the positive and negative electrode terminals 141 and 151, Since the side surface of the circular convex portion 102 c of 102 receives the rotational force from the insulating member 160 through the side surface of the concave portion 162 of the insulating member 160, the positive and negative terminals 141 and 151 can be prevented from rotating with respect to the battery lid 102.

  Therefore, when vibration or impact is applied to the assembled battery composed of the plurality of single cells 100A to 100C, the positive and negative terminals 141 and 151 are prevented from rotating with respect to the battery lid 102. And the gasket 130 interposed between the through hole 102h of the battery lid 102 is prevented from being deformed, damaged or displaced. As a result, the airtightness of the battery container can be ensured even when vibrations or impacts are applied.

(2) The position restricting portion 166 having the position restricting surface 166 a in contact with the wound electrode group 170 is provided on the insulating member 160. Accordingly, positioning can be easily performed by bringing the position restricting surface 166a of the position restricting portion 166 into contact with the wound electrode group 170 during ultrasonic bonding. Furthermore, the position regulating surface 166a regulates the movement of the wound electrode group 170 toward the battery lid 102 when vibration or impact is applied to the cells 100A to 100C. It is possible to reliably prevent the exposed portions of 171 and 172 from coming into contact with the battery lid 102 and short-circuiting.

(3) Since the circular recess 167 of the insulating member 160 is provided in the position restricting portion 166, the insulating member 160 can be made smaller than when the position restricting portion 166 and the circular recessed portion 167 are individually provided.

(4) A configuration in which the inner engagement surface 162i and the outer engagement surface 162o in the recess 162 of the insulating member 160 are arranged in parallel to the narrow surface 101b of the battery can 101 to prevent the terminal connection portions 181 and 191 from rotating. Therefore, the unit cells 100A to 100C can be formed thin.

-Second embodiment-
A secondary battery (unit cell) according to the second embodiment will be described with reference to FIGS. FIG. 10A is a perspective view showing a battery cover assembly of a unit cell according to the second embodiment of the present invention, and FIG. 10B is an exploded perspective view of the battery cover assembly. FIG. 11 is a perspective view showing the insulating member 260, and FIG. 12 is a schematic view showing an engaged state of the insulating member 260 with the negative electrode current collector 290 connected to the negative electrode terminal 251. 10 and 12 show the configuration on the negative electrode side, but since the positive electrode side has the same configuration, the reference numerals of the components on the positive electrode side are also given in parentheses for convenience. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the second embodiment, the shapes of the terminal connecting portions 281 and 291 of the positive and negative current collectors 280 and 290 and the shape of the recess 262 of the insulating member 260 are different from those of the first embodiment, but the other configurations are the same. It is.

  As shown in FIG. 10A and FIG. 10B, the terminal connection portions 281 and 291 of the positive and negative current collectors 280 and 290 protrude from the inner side surfaces 281i and 291i toward the center side of the battery can 101. Auxiliary engagement portions 289 and 299 are further provided. As shown in FIG. 11, the thick portion 265 of the insulating member 260 is cut corresponding to the shape of the auxiliary engaging portions 289 and 299, and the concave portion 262 of the insulating member 260 has the auxiliary engaging portion 289. An auxiliary engagement surface 262s that is engaged with the side surface is further provided.

  According to the second embodiment, similarly to the first embodiment, as shown in FIG. 12, the positive and negative terminals 141 and 151 are rotated around the central axis CL of the positive and negative terminals 141 and 151 as the rotation center. When the force is applied, the side surface of the concave portion 262 of the insulating member 260 receives the rotational force from the positive and negative electrode terminals 141 and 151 via the side surfaces of the terminal connection portions 281 and 291 fixed to the positive and negative electrode terminals 141 and 151, and the battery cover The side surface of the circular convex portion 102 c of 102 receives the rotational force from the insulating member 260 through the side surface of the concave portion 162 of the insulating member 260, so that the positive and negative electrode terminals 141 and 151 can be prevented from rotating with respect to the battery lid 102.

  Therefore, according to the second embodiment, as in the first embodiment, when vibration or impact is applied to an assembled battery composed of a plurality of single cells, the battery lids of the positive and negative terminals 141 and 151 Therefore, the gasket 130 interposed between each of the positive and negative terminals 141 and 151 and the through hole 102h of the battery lid 102 is prevented from being deformed, damaged, or misaligned. As a result, the airtightness of the battery container can be ensured even when vibrations or impacts are applied.

  Furthermore, the second embodiment has the following advantages over the first embodiment. For example, when rotational torque acts in the direction of the arrow T2 shown in FIG. 12, the insulating member 260 is mainly connected to the terminal connecting portions 281 and 291 in the engaging portion E21, the engaging portion E22, and the engaging portion E23 shown in FIG. Receive the power from. The insulating member 260 is a resin material having rigidity lower than that of the terminal connecting portions 281 and 291. However, as shown in FIG. 12, the insulating member 260 receives force from the terminal connecting portions 281 and 291 mainly at three locations. Compared with the first embodiment that receives the force from the terminal connection portions 281 and 291 at the place, the force acting on the insulating member 260 can be dispersed, and the deformation of the insulating member 260 can be suppressed.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
[Modification]
(1) In the first embodiment, the rectangular flat terminal connection portions 181 and 191 are fitted into the recesses 162 of the insulating member 160, and the inner side surfaces 181i and 191i and the outer side surfaces 181o of the terminal connection portions 181 and 191 are fitted. , 191o and the inner engagement surface 162i and the outer engagement surface 162o of the recess 162 have been described. In the second embodiment, the inner side surfaces 281i and 291i and the outer side surfaces 281o and 291o of the terminal connection portions 281 and 291 further including the auxiliary engagement portions 289 and 299 in the concave portion 262 of the insulating member 260, the auxiliary engagement portions 289, The configuration in which the side surface of 299 is brought into contact with the inner engagement surface 262i, the outer engagement surface 162o, and the auxiliary engagement surface 262s of the recess 262 has been described. However, the present invention is not limited to this, and the side surfaces of the terminal connecting portions 181, 191, 281, 291 are engaged with the side surfaces of the concave portions 162, 262 of the insulating members 160, 260 to rotate to the positive / negative terminals 141, 151. Various configurations that prevent rotation of the terminal connecting portions 181, 191, 281, 291 when torque acts can be employed. For example, engagement walls (not shown) parallel to the wide surface 101a may be further provided at both ends of the base portions 161 and 261 of the insulating members 160 and 260 on the wide surface 101a side. When the engagement walls are provided at both end portions on the wide surface 101a side, the stepped portions between the engagement walls 164 and the thick portions 165 and 265 and the base portions 161 and 261 may not be formed.

  (2) In the above-described embodiment, the circular convex portion 102 c of the battery lid 102 is fitted into the circular concave portions 167 of the insulating members 160 and 260, the inner peripheral side surface of the circular concave portion 167 of the insulating members 160 and 260, and the circular shape Although the configuration for engaging the outer peripheral side surface of the convex portion 102c has been described, the present invention is not limited to this. When the inner peripheral side surface of the circular concave portion 167 of the insulating members 160 and 260 is engaged with the outer peripheral side surface of the circular convex portion 102c of the battery lid 102, and the rotational torque acts on the positive and negative electrode terminals 141 and 151, the insulating member 160 , 260 can be used to prevent various rotations. For example, a circular convex portion 102c having a circular shape in plan view is provided on the battery lid 102, and a rectangular concave portion (not shown) having a rectangular shape in plan view is provided in the insulating members 160 and 260, and the circular convex portion 102c is fitted into the rectangular concave portion. You may let them. A rectangular concave portion (not shown) having a rectangular shape in plan view is provided on the insulating members 160 and 260, and a rectangular convex portion (not shown) having a rectangular shape in plan view is provided on the battery lid 102, and the rectangular concave portions of the insulating members 160 and 260 are formed. You may fit the rectangular convex part of the battery cover 102. FIG.

  (3) Although the circular recess 167 of the insulating member 160 has been described as having a circular bottom surface in plan view and an inner peripheral surface rising vertically from the bottom surface, the present invention is not limited to this. The side surface rising from the bottom surface of the circular recess 167 of the insulating member 160 may be formed as an inclined surface (tapered surface) whose inner diameter increases outward from the bottom surface. Thus, by forming the tapered surface in the circular recess 167, the circular protrusion 102c of the battery lid can be easily inserted into the circular recess 167 of the insulating member.

  (4) Although the lithium ion single battery has been described as an example of the secondary battery, the present invention can also be applied to other secondary batteries such as a nickel metal hydride battery.

  (5) The materials of the positive terminals 141 and 241, the positive current collectors 180 and 280, and the positive foil 171 are not limited to aluminum alloys, and may be aluminum. The material of the negative electrode terminals 151 and 251, the negative electrode current collectors 190 and 290, and the negative electrode foil 172 is not limited to a copper alloy, and may be copper.

  (6) In the above-described embodiment, the material of the insulating members 160 and 260 is a material in which glass fiber (GF) is mixed with “hard plastic” defined in terms of JIS K6900 plastics. It is not limited to. An insulating resin such as polybutylene terephthalate, polyphenylene sulfide, or perfluoroalkoxy fluorocarbon resin may be used.

  (7) In the above-described embodiment, the secondary battery (unit cell) constituting the assembled battery mounted on the hybrid electric vehicle or the pure electric vehicle has been described, but the present invention is not limited to this. The present invention is applied to an assembled battery that can be used for power storage devices such as other electric vehicles, such as railway vehicles such as hybrid trains, passenger cars such as buses, cargo vehicles such as trucks, and industrial vehicles such as battery-powered forklift trucks. Also good.

  (8) In the above-described embodiment, the bus bar 110 and the positive and negative terminals 141 and 151 are connected by laser welding, but the present invention is not limited to this. You may connect the bus-bar 110 and the positive / negative terminal 141,151 by electron beam welding.

  The present invention is not limited to the embodiment described above, and can be freely changed and improved without departing from the gist of the invention.

  100A to 100C single cell, 101 battery can, 101a wide surface, 101b narrow surface, 101c bottom surface, 102 battery lid, 102c circular convex portion, 102h through hole, 110 bus bar, 130 gasket, 141 positive electrode terminal, 142 external terminal portion, 142a Bus bar welding surface, 143 penetrating portion, 145 projection, 145s crimping portion, 151 negative terminal, 152 external terminal portion, 152a bus bar welding surface, 153 penetration portion, 155 projection, 155s crimping portion, 160 insulating member, 161 base portion , 161h Through-hole, 162 recess, 162a abutment surface, 162i inner engagement surface, 162o outer engagement surface, 164 engagement wall, 165 thick wall portion, 166 position restriction portion, 166a position restriction surface, 167 circular recess, 170 Winding electrode group, 173 separator, 174 positive electrode Pole, 175 negative electrode, 180 positive electrode current collector, 181 terminal connecting portion, 181i inner side surface, 181o outer side surface, 183 bonding portion, 183a bonding surface, 184 through hole, 190 negative electrode current collector, 191 terminal connecting portion, 191i inner side Side surface, 191o outer side surface, 193 joint portion, 193a joint surface, 194 through hole, 241 positive terminal, 251 negative terminal, 260 insulating member, 262 recess, 262s auxiliary engagement surface, 280 positive current collector, 281 terminal connection portion, 281i inner side surface, 289 auxiliary engagement portion, 290 negative electrode current collector, 291 terminal connection portion, 291i inner side surface

Claims (3)

A wound electrode group in which a positive electrode and a negative electrode are wound with a separator interposed therebetween;
A battery can containing the wound electrode group;
A battery lid for sealing the battery can;
A positive terminal and a negative terminal attached to each of the pair of through holes provided in the battery lid;
An insulating seal member interposed between each of the positive electrode terminal and the negative electrode terminal and the through-hole to insulate each of the positive electrode terminal and the negative electrode terminal and the battery lid;
A positive electrode current collector having an electrode connection portion connected to the positive electrode and a terminal connection portion fixed to the positive electrode terminal;
A negative electrode current collector having an electrode connection part connected to the negative electrode and a terminal connection part fixed to the negative electrode terminal;
An insulating member interposed between each of the terminal connection portions of the positive and negative electrode current collectors and the battery lid, and insulating each of the positive and negative electrode current collectors and the battery lid;
The battery lid has a convex portion protruding toward the inside of the battery can,
The insulating member has a first recess in which a terminal connection portion of the positive and negative electrode current collector is fitted, and a second recess in which a convex portion of the battery lid is fitted,
When a rotational force about the positive / negative terminal is applied to the positive / negative terminal, the side surface of the first recess of the insulating member is separated from the positive / negative terminal via the side surface of the terminal connection portion fixed to the positive / negative terminal. And the side surface of the convex portion of the battery lid receives the rotational force from the insulating member via the side surface of the second concave portion of the insulating member, whereby the positive and negative electrode terminals rotate relative to the battery lid. Prevented ,
The battery container composed of the battery can and the battery lid has a rectangular shape having a pair of wide surfaces and a pair of narrow surfaces,
The terminal connecting portion has a rectangular flat plate shape, an inner side surface and an outer side surface arranged in parallel to the narrow surface of the battery can, and a pair of wide surface sides arranged in parallel to the wide surface of the battery can And is disposed along the inner surface of the battery lid,
Wherein the first recess of the insulating member so as to engage the outer side surface of the inner engagement surface that is arranged parallel to the narrow faces so as to engage the inner side surface of the terminal connecting portion and the terminal connecting portion It has an outer engagement surface arranged in parallel to the narrow surface, but does not have an engagement surface that engages with each of the pair of wide surface side surfaces of the terminal connecting portion. Secondary battery. The secondary battery according to claim 1 ,
The terminal connection portion is further provided with an auxiliary engagement portion that protrudes from the inner side surface toward the center side of the battery can,
The secondary battery according to claim 1, wherein an auxiliary engagement surface that is engaged with a side surface of the auxiliary engagement portion is further provided in the first recess of the insulating member. The secondary battery according to claim 1 or 2 ,
The insulating member is provided with a position restricting portion having a surface in contact with the wound electrode group,
The secondary battery, wherein the second concave portion of the insulating member is provided corresponding to the position restricting portion.

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