JP6107266B2 - Secondary battery and method for manufacturing secondary battery - Google Patents

Description

  The present invention relates to a secondary battery having a mechanism for cutting off a current path and a method for manufacturing the secondary battery.

  Patent Document 1 describes a secondary battery including a current interruption mechanism that interrupts a current path of the secondary battery when the internal pressure of the secondary battery increases. The current interrupt mechanism is disposed on the current path, and can interrupt the current flowing through the secondary battery by mechanically breaking a part of the current path. According to the technique described in Patent Document 1, by inserting the insertion portion of the current collecting tab member into the tab receiving portion of the current collecting tab holder, it is possible to suppress the impact and vibration from being applied to the thin portion of the insertion portion. ing.

Japanese Patent Laying-Open No. 2008-066254 (paragraph [0049], FIG. 3)

  With the technique described in Patent Document 1, it is possible to suppress vibration from being applied to the thin portion of the insertion portion, but vibration is likely to be applied to other portions of the current interrupt mechanism. Specifically, in Patent Document 1, the hook portion of the insulating plate is fitted into the fixing portion of the current collecting tab holder, but a gap is generated between the fixing portion and the hook portion due to a manufacturing error or the like. As a result, rattling occurs between the fixed portion and the hook portion, and the current collecting tab holder and the like are likely to vibrate, and a load is easily applied to the current interrupt mechanism. Here, if an excessive load is applied to the current interruption mechanism, the current interruption mechanism may malfunction.

  The secondary battery according to the first invention of the present application includes a power generation element that performs charge and discharge, a case that houses the power generation element in a sealed state, a current collector that is housed in the case and is electrically connected to the power generation element, A deformable member that deforms in response to an increase in the internal pressure of the case and breaks the mechanical connection with the current collector. Furthermore, the secondary battery has an electrode terminal that protrudes outside the case and is electrically connected to the deformable member, and a holder that is formed of an insulating material and supports the current collector while being fixed to the case. . Here, the holder has a boss. The boss penetrates the current collector, and the tip of the boss is formed along the outer surface of the current collector by heat caulking.

  In the first invention of this application, the holder supports the current collector using a boss. Specifically, the current collector is supported by passing the boss through the current collector and forming the tip of the boss along the outer surface of the current collector by thermal caulking. By subjecting the boss to a heat caulking process, the boss can be brought into contact with the current collector without a gap. Thereby, it can suppress that a backlash generate | occur | produces in the part which supports a collector with a holder, and can suppress a vibration of a collector. Since the current collector is mechanically connected to the deformable member, it is possible to suppress an excessive load from being applied to the connecting portion of the current collector and the deformable member by suppressing vibration of the current collector. .

  The deformable member can be fixed to the lead member. The lead member penetrates the case from the inside to the outside of the case and is electrically connected to the electrode terminal. Here, the holder can be disposed between the lead member and the case. The electrode terminal is a terminal used for connecting the secondary battery to a load. When the case is formed of a conductive material such as metal, it is necessary to insulate the lead member through which current flows from the case. Therefore, by arranging a holder made of an insulating material between the lead member and the case, the lead member and the case can be in an insulated state.

  By using the lead member, the holder can be pressed against the case. Specifically, the lead member can press the holder against the case by sandwiching the holder and the case. By pressing the holder against the case, the holder can be positioned with respect to the case, and the current collector supported by the holder can also be positioned.

  A through hole through which the boss passes can be formed in the current collector. That is, the boss is formed along the through hole in a state of passing through the through hole of the current collector. Here, a through-hole can be arrange | positioned in the outer edge side of an electrical power collector rather than the part mechanically connected with a deformation | transformation member among electrical power collectors. By positioning the through-hole on the outer edge side of the current collector, the region inside the current collector can be effectively used as a part for mechanically connecting the current collector and the deformable member.

  A through-hole can be comprised by the 1st area | region located in the base end part side of a boss | hub, and the 2nd area | region which is located in the front end part side of a boss | hub and has a width | variety wider than a 1st area | region. Here, the boss can be formed in a shape along the first region and the second region. Since the second region has a width wider than that of the first region, forming the boss along the first region and the second region can prevent the boss from coming out of the through hole. it can.

  The current collector can be constituted by a pedestal and arms. A through hole is formed in the base. The arm portion extends from the outer edge of the pedestal toward the power generation element in a bent state, and is fixed to the power generation element. Here, the thickness of the boss can be increased continuously or stepwise from the proximal end portion of the boss toward the distal end portion of the boss. And the front-end | tip part of a boss | hub can be shifted to the arm part side with respect to the base end part of a boss | hub.

  By shifting the tip of the boss toward the arm with respect to the base end of the boss, the boss can be asymmetrical. That is, the boss can be offset toward the arm portion side, and the volume of the boss adjacent to the arm portion can be increased. Thus, if the volume of a boss | hub is increased, the intensity | strength of a boss | hub can be improved.

  The arm portion is bent with respect to the pedestal, but when the arm portion is bent, stress may concentrate on the boss. As described above, when the boss is shifted toward the arm portion, the strength of the boss can be improved on the arm portion side. For this reason, even if stress is concentrated on the boss during bending of the arm portion, the boss can withstand this stress.

  Here, if the boss is shifted toward the arm portion, it is difficult to improve the strength of the boss on the side away from the arm portion. However, since the stress generated during bending is likely to act on a part of the boss located on the arm portion side, it is not necessary to improve the strength of the boss on the side away from the arm portion. Moreover, if the volume increase of the boss | hub is suppressed in the side away from the arm part, the material which forms a boss | hub can be reduced and cost reduction can be aimed at.

  A taper surface can be formed on the boss, and the taper surface extends toward the tip of the boss. When a tapered surface is formed on the boss, the taper angle of the first region (part of the taper surface) located on the arm portion side is set to the second region (part of the taper surface) located on the side away from the arm portion. The taper angle can be made larger. Thereby, the strength of the boss can be improved on the arm portion side, and the boss can withstand the stress generated during the bending of the arm portion.

  As described above, when the current collector is constituted by the pedestal and the arm portion, a concave portion can be formed in the bent portion of the arm portion. By forming the recesses in this way, it becomes easier to bend the arm portion during bending. If the arm portion is easily bent, the stress acting on the boss can be reduced when the arm portion is bent. Thereby, it is possible to prevent the boss from being broken due to stress concentration on the boss during bending of the arm portion.

  Here, if the concave portion is formed along the bent portion of the arm portion, the arm portion can be easily bent. Specifically, the recess can be extended in the direction along the bent part. Thereby, a recessed part can be increased in the part bent and an arm part can be made easy to bend.

  The current collector can be provided with a pair of arms. Here, a power generation element can be disposed between the pair of arms. Thereby, each arm part can be fixed to a power generation element. When a pair of arm portions is provided on the current collector, the jig may interfere with the arm portions when the boss is caulked. Therefore, when performing a heat caulking process using a jig, interference between the jig and the arm can be prevented by widening the distance between the pair of arms. After performing the heat caulking process, by bending at least one of the arm portions, the distance between the pair of arm portions can be narrowed and each arm portion can be fixed to the power generation element.

  In the configuration in which the boss is passed through the through hole of the current collector, the tip of the boss can be positioned in a plane including the end of the through hole. That is, it is possible to prevent the boss from protruding from the through hole. If the boss does not protrude from the through hole, it is not necessary to avoid interference with the boss, and the space formed inside the case can be used effectively. For example, the power generation element accommodated in the case can be enlarged.

  The current collector can be provided with a protrusion extending toward the tip end side of the boss along the boss. When a heat caulking process is performed on the boss, heat can be easily transmitted to the boss by using the protrusion. For example, when the through hole into which the boss is inserted is formed in the current collector, the protrusion can be formed at a position continuous with the through hole.

  When performing the heat caulking process, the hot plate is brought into contact with the tip of the boss to melt the boss. Here, the portion of the boss that contacts the hot plate is easy to melt, but the portion that does not contact the hot plate is difficult to melt. Specifically, the portion of the boss adjacent to the protrusion of the current collector is difficult to melt. For this reason, by providing protrusions on the current collector and transferring heat to the protrusions, heat can be applied to portions of the boss that are difficult to melt. This makes it easy to melt the entire portion of the boss to be melted by the heat caulking process, and can secure the strength of the boss after the heat caulking process.

  A second invention of the present application is a method for manufacturing a secondary battery according to the first invention of the present application. In this manufacturing method, first, the boss formed on the holder is passed through the current collector. Next, a heat caulking process is performed on the tip of the boss protruding from the current collector, thereby forming the tip of the boss along the outer surface of the current collector. Also in the second invention of the present application, the same effect as that of the first invention of the present application can be obtained.

  Here, a protrusion extending toward the tip of the boss is provided on the current collector along the boss, and heat can be applied to the protrusion of the current collector in the heat caulking process. As a result, heat of the caulking process can be applied not only to the tip of the boss but also to the portion of the boss adjacent to the protrusion of the current collector, and the entire portion of the boss to be melted can be easily Can be melted. By melting the boss in this manner, the strength of the boss after the heat caulking process can be ensured.

It is an external view of a secondary battery. It is a figure which shows the internal structure of a secondary battery. It is an expanded view of an electric power generation element. It is an external view of a power generation element. It is a figure which shows the structure which connects a positive electrode terminal and a positive electrode collector, and the structure which connects a negative electrode terminal and a negative electrode collector. It is an external view of a collector holder. It is an external view of a positive electrode collector. It is a top view of the lid | cover provided with the positive electrode terminal and the negative electrode terminal. It is A1-A1 sectional drawing of FIG. FIG. 10 is an enlarged view of a region R1 shown in FIG. It is a front view of the lid | cover provided with the positive electrode terminal and the negative electrode terminal. It is the figure seen from the direction shown by the arrow B of FIG. In Example 2, it is a figure explaining the connection method of a collector holder and a positive electrode collector. In Example 2, it is a figure explaining the connection method of a collector holder and a positive electrode collector. In Example 2, it is a figure explaining the connection method of a collector holder and a positive electrode collector. In Example 2, it is a figure explaining the connection method of a collector holder and a positive electrode collector. In the comparative example of Example 2, it is a figure which shows the connection structure of a collector holder and a positive electrode collector. In Example 3, it is an external view which shows a part of lid | cover with which the collector holder and the positive electrode collector were attached. In Example 3, it is a figure explaining the heat caulking process of a boss | hub, and the bending process of a positive electrode electrical power collector. It is A2-A2 sectional drawing of FIG. It is A2-A2 sectional drawing of FIG. It is a figure when it sees from the direction of arrow D2 of FIG. FIG. 20 is a diagram corresponding to FIG. 19 and showing a modification of the third embodiment. FIG. 20 is a diagram corresponding to FIG. 19 and showing a modification of the third embodiment. FIG. 18 is a diagram corresponding to FIG. 17 and showing a modification of the third embodiment. FIG. 11 is a diagram corresponding to FIG. 10 and showing a modification of the third embodiment. In Example 4, it is an external view which shows a part of lid | cover with which the collector holder and the positive electrode collector were attached. It is a figure when it sees from the direction of arrow D3 of FIG. It is an enlarged view of area | region R4 shown in FIG. In the modification of Example 4, it is the schematic which shows a part of positive electrode electrical power collector.

  Examples of the present invention will be described below.

  First, the configuration of the secondary battery will be described. As the secondary battery, for example, a nickel metal hydride battery or a lithium ion battery can be used. The secondary battery can be mounted on a vehicle, for example. If the electrical energy output from the secondary battery is converted into kinetic energy, the vehicle can be driven using this kinetic energy.

  Here, when the secondary battery is mounted on the vehicle, the assembled battery can be configured using a plurality of secondary batteries (single cells), and the assembled battery can be mounted on the vehicle. The assembled battery can be configured by electrically connecting a plurality of secondary batteries in series or electrically in parallel.

  FIG. 1 is an external view of a secondary battery, and FIG. 2 is a diagram showing an internal structure of the secondary battery. 1 and 2, the X axis, the Y axis, and the Z axis are axes orthogonal to each other. The relationship among the X axis, the Y axis, and the Z axis is the same in other drawings. In this embodiment, the axis corresponding to the vertical direction is the Z axis.

  The secondary battery 1 includes a battery case 10 and a power generation element 20 accommodated in the battery case 10. The secondary battery 1 is a so-called square battery, and the battery case 10 is formed along a rectangular parallelepiped. The battery case 10 can be made of metal, for example, and has a case body 10a and a lid 10b. The case body 10a has an opening for incorporating the power generation element 20, and the lid 10b closes the opening of the case body 10a. Thereby, the inside of the battery case 10 is hermetically sealed. The lid 10b and the case main body 10a can be fixed by welding, for example.

  The positive terminal 110 and the negative terminal 120 are fixed to the lid 10b. The positive electrode terminal 110 is electrically connected to the positive electrode current collector 111 housed in the battery case 10, and the positive electrode current collector 111 is electrically connected to the power generation element 20. The negative electrode terminal 120 is electrically connected to the negative electrode current collector 121 accommodated in the battery case 10, and the negative electrode current collector 121 is electrically connected to the power generation element 20.

  The lid 10b is provided with a valve 10c. The valve 10 c is used to discharge gas to the outside of the battery case 10 when gas is generated inside the battery case 10. Specifically, when the internal pressure of the battery case 10 reaches the operating pressure of the valve 10c as the gas is generated, the valve 10c changes from a closed state to an open state, thereby discharging the gas to the outside of the battery case 10. Let

  In this embodiment, the valve 10c is a so-called destructive valve, and is configured by engraving the lid 10b. As the valve 10c, a so-called return type valve can be used. The return type valve reversibly changes between a closed state and an open state in accordance with the relationship between the internal pressure and the external pressure (atmospheric pressure) of the battery case 10.

  A liquid injection port 10d is formed in the lid 10b adjacent to the valve 10c. The liquid injection port 10 d is used for injecting an electrolytic solution into the battery case 10. Here, after housing the power generation element 20 in the case main body 10a, the lid 10b is fixed to the case main body 10a. In this state, an electrolytic solution is injected into the battery case 10 from the liquid injection port 10d. After injecting the electrolytic solution into the battery case 10, the injection port 10 d is closed by the injection plug 11.

  FIG. 3 is a development view of the power generation element 20. The power generation element 20 includes a positive electrode plate 21, a negative electrode plate 22, and a separator 23. The positive electrode plate 21 includes a current collector foil 21a and a positive electrode active material layer 21b formed on the surface of the current collector foil 21a. The positive electrode active material layer 21b includes a positive electrode active material, a conductive agent, a binder, and the like. The positive electrode active material layer 21b is formed in a partial region of the current collector foil 21a, and the remaining region of the current collector foil 21a is exposed.

  The negative electrode plate 22 includes a current collector foil 22a and a negative electrode active material layer 22b formed on the surface of the current collector foil 22a. The negative electrode active material layer 22b includes a negative electrode active material, a conductive agent, a binder, and the like. The negative electrode active material layer 22b is formed in a partial region of the current collector foil 22a, and the remaining region of the current collector foil 22a is exposed. The positive electrode active material layer 21b, the negative electrode active material layer 22b, and the separator 23 are impregnated with an electrolytic solution.

  The power generation element 20 is configured by laminating the positive electrode plate 21, the negative electrode plate 22, and the separator 23 in the order shown in FIG. 3, and winding this laminate in the direction indicated by the arrow C in FIG. Specifically, after the laminated body is wound concentrically, the wound laminated body is deformed along the inner wall surface of the battery case 10. Thereby, the electric power generation element 20 is comprised and the electric power generation element 20 can be accommodated in the battery case 10. FIG.

  In FIG. 4, only the current collector foil 21 a of the positive electrode plate 21 is wound at one end of the power generation element 20 in the Y direction. A positive electrode current collector 111 shown in FIG. 2 is fixed to the current collector foil 21a. For example, the current collector foil 21a and the positive electrode current collector 111 can be welded. At the other end of the power generation element 20 in the Y direction, only the current collector foil 22a of the negative electrode plate 22 is wound, and the negative electrode current collector 121 shown in FIG. 2 is fixed to the current collector foil 22a. For example, the current collector foil 22a and the negative electrode current collector 121 can be welded. In the central portion of the power generation element 20 in the Y direction, the positive electrode active material layer 21b and the negative electrode active material layer 22b face each other with the separator 23 interposed therebetween, and a chemical reaction is performed when the secondary battery 1 is charged and discharged.

  For example, when a lithium ion battery as the secondary battery 1 is discharged, a chemical reaction that releases lithium ions and electrons is performed at the interface of the negative electrode active material, and the lithium ions and electrons are absorbed at the interface of the positive electrode active material. A chemical reaction takes place. When charging a lithium ion battery, a reaction opposite to that during discharging is performed. When the positive electrode plate 21 and the negative electrode plate 22 exchange lithium ions via the separator 23, the lithium ion battery is charged and discharged.

  FIG. 5 is a diagram illustrating a structure in which the positive electrode terminal 110 and the positive electrode current collector 111 are electrically connected and a structure in which the negative electrode terminal 120 and the negative electrode current collector 121 are electrically connected. First, a structure for electrically connecting the positive electrode terminal 110 and the positive electrode current collector 111 will be described.

  The positive terminal 110 has a shaft part 110a and a head part 110b. The shaft part 110a is inserted into the first opening part 112a of the external connection terminal 112, and the head part 110b contacts the peripheral part of the first opening part 112a. Thereby, the positive terminal 110 can be fixed to the external connection terminal 112. Here, the shaft portion 110a extends upward from the first opening portion 112a. Further, the external connection terminal 112 is disposed outside the battery case 10.

  An external insulating member 113 made of an insulating material such as resin is disposed between the external connection terminal 112 and the lid 10b. The external insulating member 113 is used to insulate the external connection terminal 112 and the lid 10b. The external insulating member 113 has a recess 113a, and the head portion 110b of the positive electrode terminal 110 is accommodated in the recess 113a. Since the recess 113a is formed in a shape along the head 110b, the head 110b can be positioned by housing the head 110b in the recess 113a.

  A current collector holder 114 is disposed inside the battery case 10. The current collector holder 114 is used to support the positive electrode current collector 111. The current collector holder 114 has a holder main body 114a, a cylindrical portion 114b, and a leg portion 114c, and is made of an insulating material such as resin. The cylindrical portion 114b extends upward from the holder main body 114a and is inserted into a through hole 10e formed in the lid 10b. The current collector holder 114 has four leg portions 114c, and each leg portion 114c extends downward from the holder main body 114a.

  A lead member 115 is disposed inside the battery case 10, and the lead member 115 is formed of a conductive material such as metal. The lead member 115 includes a lead main body 115a and a cylindrical portion 115b extending upward from the lead main body 115a. The cylindrical portion 115 b is inserted into the cylindrical portion 114 b of the current collector holder 114, the through hole 113 b of the external insulating member 113, and the second opening 112 b of the external connection terminal 112.

  Here, the cylindrical portion 114b of the current collector holder 114 is located between the cylindrical portion 115b and the through hole 10e of the lid 10b. A holder body 114a is located between the lead body 115a and the lid 10b. Thereby, the lead member 115 and the lid 10b are in an insulated state by sandwiching the current collector holder 114 formed of an insulating material.

  The tip of the cylindrical portion 115 b protrudes from the second opening 112 b of the external connection terminal 112 to the outside (upward) of the battery case 10. A crimping process is performed on the tip of the cylindrical portion 115b protruding from the second opening 112b. FIG. 5 shows the cylindrical portion 115b after the caulking process is performed. By caulking the tip of the cylindrical portion 115b, the external connection terminal 112, the external insulating member 113, the lid 10b, the current collector holder 114 (the holder main body 114a), and the lead main body 115a by the tip of the cylindrical portion 115b. Can be fixed to each other in a state of sandwiching. Here, the current collector holder 114 is pressed against the lid 10b by the lead member 115 and is in close contact with the lid 10b.

  The lead body 115 a is surrounded by the leg portions 114 c of the current collector holder 114 and is positioned with respect to the current collector holder 114. That is, by using the four leg portions 114 c, the movement of the lead member 115 can be prevented, and the lead member 115 can be prevented from being displaced with respect to the current collector holder 114.

  The pressure-sensitive member (corresponding to the deformable member) 116 is made of a conductive material such as metal and is fixed to the lead body 115 a of the lead member 115. For example, the pressure-sensitive member 116 and the lead body 115a can be fixed by welding. Since the space formed inside the lead member 115 is connected to the atmosphere, the pressure-sensitive member 116 and the lead body 115a need to be in close contact with each other in order to ensure airtightness inside the secondary battery 1.

  A deformation portion 116 a is provided at the center of the pressure-sensitive member 116, and the deformation portion 116 a protrudes toward the positive electrode current collector 111. The positive electrode current collector 111 has a pedestal 111a, and the pedestal 111a has a fracture portion 111b to which the deformable portion 116a is fixed. The fracture portion 111b is used to block the current path of the secondary battery 1 as will be described later.

  The thickness of the fracture portion 111b is thinner than the thickness of the region of the base 111a excluding the fracture portion 111b. For example, the deformable portion 116a and the fracture portion 111b can be fixed by welding a plurality of locations. A cutout can be formed in the base 111a along the outer edge of the fracture portion 111b. By forming the notch, it is possible to easily break the fracture portion 111b when the internal pressure of the secondary battery 1 increases.

  Further, the tips of the leg portions 114 c of the current collector holder 114 are fixed to the base 111 a of the positive electrode current collector 111. As shown in FIG. 6, a boss 114d is provided at the tip of the leg 114c. Further, as shown in FIG. 7, through holes 111c are provided at four corners of the base 111a.

  The four bosses 114d and the four through holes 111c are provided at positions corresponding to each other. Since the holder main body 114a is formed in a shape along the base 111a, the bosses 114d provided at the four corners of the holder main body 114a correspond to the through holes 111c provided at the four corners of the base 111a. Will do.

  The current collector holder 114 can be positioned on the pedestal 111 a of the positive electrode current collector 111 by inserting each boss 114 d into the corresponding through hole 111 c. Since the current collector holder 114 (including the boss 114d) is an insulating material and is formed of a thermoplastic material, as described later, by applying heat to the boss 114d to deform (melt) it, The boss 114d can be fixed to the through hole 111c.

  Thereby, the collector holder 114 can be fixed to the positive electrode collector 111 (pedestal 111a). As described above, the current collector holder 114 is fixed in close contact with the lid 10b. Therefore, by fixing the positive electrode current collector 111 to the current collector holder 114, the positive electrode current collector 111 is fixed inside the battery case 10. The current collector 111 can be positioned.

  Further, since the current collector holder 114 and the positive electrode current collector 111 are fixed using the four bosses 114d and the four through holes 111c, the current collector holder 114 can easily support the positive electrode current collector 111. Become. That is, the current collector holder 114 supports the positive electrode current collector 111 at a plurality of locations (locations of the bosses 114d and the through holes 111c), and therefore, a connection portion between the current collector holder 114 and the positive current collector 111. The strength at can be ensured.

  Here, the lead member 115 and the pressure sensitive member 116 are disposed between the current collector holder 114 (holder main body 114 a) and the base 111 a of the positive electrode current collector 111. Since the lead member 115 and the pressure sensitive member 116 are surrounded by the four legs 114c of the current collector holder 114, the lead member 115 and the pressure sensitive member 116 are displaced between the holder main body 114a and the base 111a. Can be suppressed.

  In this embodiment, four bosses 114d and four through holes 111c are used, but the number of bosses 114d and through holes 111c can be set as appropriate. The through-hole 111c should just be formed in the position along the outer edge of the base 111a. The boss 114d only needs to be provided at a position corresponding to the through hole 111c. Similarly, the number of legs 114c can be set as appropriate. In this embodiment, the bosses 114d are provided on all the leg portions 114c, but the bosses 114d may be provided only on some of the leg portions 114c. Furthermore, the shape of the pedestal 111a can also be set as appropriate.

  In the present embodiment, the through hole 111c penetrates the pedestal 111a, but the present invention is not limited to this. For example, a notch (recess) can be provided on the outer edge of the base 111a, and the boss 114d can be inserted into the notch. Here, the notch has the same function as the through hole 111c.

  The positive electrode current collector 111 has an arm portion 111d extending downward from the pedestal 111a. The arm portion 111d is formed to be bent so as not to interfere with the power generation element 20. That is, the arm portion 111 d is disposed at a position away from the power generation element 20. The tip of the arm portion 111 d is fixed to the current collector foil 21 a exposed at the end of the power generation element 20. For example, the tip of the arm portion 111d and the current collecting foil 21a of the power generation element 20 can be welded.

  When gas is generated inside the battery case 10 and the internal pressure of the battery case 10 rises, the deforming portion 116a is deformed to become convex toward the lead member 115 (lead body 115a). That is, the deforming portion 116a changes from a convex shape toward the positive electrode current collector 111 (base 111a) to a convex shape toward the lead member 115 (lead body 115a).

  Since the inside of the lead member 115 fixed to the pressure-sensitive member 116 is connected to the atmosphere, the pressure-sensitive member 116 is positioned at the boundary between the atmosphere and the space that houses the power generation element 20. For this reason, when the internal pressure of the battery case 10 increases due to the generation of gas, the pressure-sensitive member 116 deforms in a direction away from the positive electrode current collector 111 (base 111a). When the deforming portion 116a is deformed, the break portion 111b fixed to the deformable portion 116a is broken, and the break portion 111b is separated from the base 111a.

  The current path between the positive electrode terminal 110 and the positive electrode current collector 111 can be interrupted by the breakage portion 111b being separated from the pedestal 111a together with the deformation portion 116a. Thereby, in the state which gas generate | occur | produced inside the battery case 10, charging / discharging of the electric power generation element 20 can be prevented. A pressure (referred to as an operating pressure) when the deforming portion 116a is deformed can be appropriately set in consideration of the internal pressure of the battery case 10 and the like.

  Next, a structure for electrically connecting the negative electrode terminal 120 and the negative electrode current collector 121 will be described.

  The negative terminal 120 has a shaft portion 120a and a head portion 120b. The shaft 120a is inserted into the first opening 122a of the external connection terminal 122, and the head 120b is in contact with the peripheral portion of the first opening 122a. Thereby, the negative electrode terminal 120 can be fixed to the external connection terminal 122. Here, the shaft portion 120a extends upward from the first opening portion 122a. Further, the external connection terminal 122 is disposed outside the battery case 10.

  An external insulating member 123 made of an insulating material such as a resin is disposed between the external connection terminal 122 and the lid 10b. The external insulating member 123 is used to insulate the external connection terminal 122 and the lid 10b. The external insulating member 123 has a concave portion 123a, and the head portion 120b of the negative electrode terminal 120 is accommodated in the concave portion 123a. The recess 123a is formed in a shape along the head 120b, and the head 120b can be positioned by housing the head 120b in the recess 123a.

  An internal insulating member 124 is disposed inside the battery case 10. The internal insulating member 124 includes a plate portion 124a and a cylindrical portion 124b extending upward from the plate portion 124a. The cylindrical portion 124b is inserted into the through hole 10f formed in the lid 10b.

  The negative electrode current collector 121 includes a pedestal 121a, a cylindrical portion 121b extending upward from the pedestal 121a, and an arm portion 121c extending downward from the pedestal 121a. The cylindrical portion 121 b is inserted into the cylindrical portion 124 b of the internal insulating member 124, the through hole 123 b of the external insulating member 123, and the second opening 122 b of the external connection terminal 122.

  Here, the cylindrical portion 124b of the internal insulating member 124 is located between the cylindrical portion 121b and the through hole 10f of the lid 10b. Further, the plate portion 124a of the internal insulating member 124 is located between the lid 10b and the pedestal 121a. Thus, the negative electrode current collector 121 and the lid 10b are in an insulated state by sandwiching the internal insulating member 124 therebetween.

  The tip of the cylindrical part 121b protrudes outside (upward) the battery case 10 from the second opening 122b. A crimping process is performed on the tip of the cylindrical part 121b protruding from the second opening part 122b. FIG. 5 shows the cylindrical portion 121b after the caulking process is performed. By crimping the tip of the cylindrical part 121b, the external connection terminal 122, the external insulating member 123, the lid 10b, and the internal insulating member 124 (plate) are formed by the tip of the cylindrical part 121b and the base 121a of the negative electrode current collector 121. They can be fixed to each other in a state of sandwiching the portion 124a).

  FIG. 8 is a top view of the lid 10b to which the positive electrode terminal 110, the negative electrode terminal 120, and the like are fixed. 9 is a cross-sectional view taken along line A1-A1 of FIG. FIG. 10 is an enlarged view of the through hole 111c in the region R1 shown in FIG. 11 is a front view of the lid 10b to which the positive electrode terminal 110, the negative electrode terminal 120, and the like are fixed, and FIG. 12 is a diagram when viewed from the direction indicated by the arrow B in FIG. In FIG. 12, the connection part of the collector holder 114 and the positive electrode collector 111 is shown.

  A structure for fixing the boss 114 d of the current collector holder 114 and the pedestal 111 a of the current collector 111 will be described with reference to FIGS. 8 to 12.

  As shown in FIG. 10, the through-hole 111c has a first region 111c1 having a diameter r1 and a second region 111c2 having a diameter r2. The diameter r2 is larger than the diameter r1, and the boss 114d is inserted into the through hole 111c from the first region 111c1 side. The boss 114d is formed along the first region 111c1 of the through hole 111c, and the diameter of the boss 114d is slightly smaller than the diameter r1 of the first region 111c1.

  When the boss 114d is inserted into the through hole 111c, the boss 114d penetrates the through hole 111c, and the tip of the boss 114d protrudes from the through hole 111c. By applying heat to the tip of the boss 114d protruding from the through hole 111c and deforming it, the tip of the boss 114d can be formed in a shape along the second region 111c2 of the through hole 111c (see FIG. 9). ).

  Thereby, the boss 114d is formed in a shape along the first region 111c1 and the second region 111c2 of the through hole 111c. In other words, the thermoformed boss 114d has a region with a diameter r1 and a region with a diameter r2. By making the shape of the boss 114d along the through hole 111c (the first region 111c1 and the second region 111c2), the boss 114d can be prevented from coming out of the through hole 111c.

  The tip of the boss 114d after thermoforming does not protrude from the through hole 111c, but is formed along the surface of the base 111a, in other words, the plane on which the end of the through hole 111c is located. By not projecting the tip of the boss 114d from the through hole 111c, the space inside the battery case 10 can be expanded.

  Here, if the tip end of the boss 114d is protruded from the through hole 111c, the power generating element 20 must be arranged so as to avoid interference with the boss 114d protruding from the through hole 111c. In this embodiment, since the boss 114d does not protrude from the through hole 111c, it is not necessary to consider interference with the boss 114d, and the space inside the battery case 10 can be expanded. If the space inside the battery case 10 can be expanded, the power generating element 20 can be enlarged, and the battery capacity (full charge capacity) can be secured.

  In the present embodiment, the through hole 111c is configured by the first region 111c1 and the second region 111c2, but is not limited thereto. For example, the through hole 111c can be configured only by the first region 111c1. In this case, it is possible to prevent the boss 114d from coming out of the through hole 111c by protruding the tip of the boss 114d from the through hole 111c and thermoforming the protruding portion of the boss 114d. Here, the protruding portion of the boss 114d is formed in a shape along the base 111a by thermoforming.

  In this embodiment, the boss 114d is formed in a columnar shape, and the through hole 111c is formed in a shape along the outer shape of the boss 114d. However, the present invention is not limited to this. That is, the shapes of the boss 114d and the through hole 111c can be set as appropriate. For example, the boss 114d can be formed in a shape along a rectangular parallelepiped. Moreover, the through-hole 111c should just be formed in the shape along the external shape of the boss | hub 114d.

  According to the present embodiment, the lead member 115, the pressure sensitive member 116, and the positive electrode current collector 111 are suppressed from vibrating, and an excessive load is suppressed from being applied to the connecting portion of the deformable portion 116a and the fracture portion 111b. be able to. This will be specifically described below.

  The secondary battery 1 may vibrate under the influence of the outside. In particular, when the secondary battery 1 is mounted on a vehicle, it is easy to receive vibration from the vehicle during traveling. When vibration is applied to the secondary battery 1, members disposed inside the secondary battery 1 are also likely to vibrate. In this embodiment, the current collector holder 114 is fixed in close contact with the lid 10b, and the positive electrode current collector 111 is fixed to the current collector holder 114. Vibration can be suppressed.

  In particular, since the current collector holder 114 and the positive electrode current collector 111 are fixed using the four bosses 114d and the four through holes 111c, a place where the current collector holder 114 supports the positive electrode current collector 111 is provided. As a result, the positive electrode current collector 111 can be stably supported. Further, as shown in FIG. 9, since the boss 114d is formed along the through hole 111c, it is possible to suppress the play between the current collector holder 114 and the positive electrode current collector 111.

  By suppressing the backlash between the current collector holder 114 and the positive electrode current collector 111, vibration is applied to the lead member 115 and the pressure sensitive member 116 disposed between the current collector holder 114 and the positive electrode current collector 111. Can be suppressed. By suppressing the vibration from being applied to the positive electrode current collector 111 and the pressure sensitive member 116, it is possible to suppress an excessive load from being applied to the connecting portion between the deformable portion 116a and the fracture portion 111b.

  When an excessive load is applied to the connecting portion between the deforming portion 116a and the fracture portion 111b, the operating pressure of the deforming portion 116a when the current path is interrupted varies. The vibration to the body 111 and the pressure-sensitive member 116 can be suppressed, and the occurrence of variations in the operating pressure of the deforming portion 116a can be suppressed. Here, when the breakage portion 111b is formed by forming a notch in the pedestal 111a, the strength of the breakage portion 111b tends to decrease. In a state where the strength of the fracture portion 111b is reduced, it is preferable not to apply an excessive load to the connection portion between the deformable portion 116a and the fracture portion 111b.

  Further, by providing the through holes 111c at the four corners of the pedestal 111a, it becomes easy to form the fractured portion 111b connected to the deformable portion 116a at the center of the pedestal 111a. Furthermore, by providing the current collector holder 114 with four legs 114c, a space S (for guiding the gas generated from the power generation element 20 or the like to the pressure-sensitive member 116 between the holder main body 114a and the base 111a. FIG. 12) can be formed. Thereby, when the internal pressure of the battery case 10 increases, the pressure-sensitive member 116 is easily affected by the increase in internal pressure, and the operating performance of the pressure-sensitive member 116 can be improved.

  A second embodiment of the present invention will be described. Here, the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The present embodiment relates to a structure for connecting the current collector holder 114 and the positive electrode current collector 111. Specifically, the present invention relates to a structure suitable when the boss 114d of the current collector holder 114 and the through hole 111c of the positive electrode current collector 111 are fixed by thermal caulking.

  13A to 13D are views for explaining a method of fixing the boss 114d of the current collector holder 114 and the through hole 111c of the positive electrode current collector 111. FIG. Through the steps shown in FIGS. 13A, 13B, and 13C, the structure shown in FIG. 13D is obtained. Note that the structure shown in FIG. 13D is different from the connection structure of the boss 114d and the through hole 111c described in the first embodiment.

  As shown in FIG. 13A, a protrusion 111e is formed in the through hole 111c formed in the pedestal 111a. A part of the protrusion 111e is continuous with the through hole 111c. In other words, the protrusion 111e is formed along the through hole 111c. The boss 114d penetrates the through hole 111c, and the tip of the boss 114d protrudes from the through hole 111c. The hot plate 30 used in the heat caulking process has a recess 31 and moves in the direction indicated by the arrow C when the heat caulking process is performed. The hot plate 30 is heated by a heater (not shown).

  As shown in FIG. 13B, when the recess 31 of the hot plate 30 contacts the tip of the boss 114d, the tip of the boss 114d is melted. Since the current collector holder 114 (including the boss 114d) is formed of a thermoplastic material, the boss 114d can be melted by applying heat to the boss 114d. As the hot plate 30 moves in the direction indicated by the arrow C, the melted portion of the boss 114 d spreads along the recess 31.

  As shown in FIG. 13C, when the hot plate 30 contacts the pedestal 111a of the positive electrode current collector 111, the movement of the hot plate 30 stops. When the hot plate 30 comes into contact with the pedestal 111a, the melted portion of the boss 114d is accommodated in a region surrounded by the recess 31 of the hot plate 30 and the pedestal 111a. Here, the recess 31 is separated from the tip of the protrusion 111e, and a melted portion of the boss 114d exists between the recess 31 and the protrusion 111e. The shorter the distance between the recess 31 and the protrusion 111e, the more easily the strength and the strength of the boss 114d after the heat caulking process are reduced. For this reason, the space | interval of the recessed part 31 and the processus | protrusion 111e can be set suitably in consideration of the intensity | strength requested | required of the boss | hub 114d.

  The portion of the boss 114 d that contacts the recess 31 is melted by receiving heat from the hot plate 30. The portion of the boss 114 d that does not contact the recess 31 receives heat from the hot plate 30. Difficult to melt. Specifically, a portion of the boss 114d adjacent to the protrusion 111e is less likely to receive heat from the hot plate 30 and is difficult to melt.

  In the present embodiment, when the hot plate 30 comes into contact with the pedestal 111a, the heat of the hot plate 30 is transmitted to the protrusion 111e through the pedestal 111a. Since the pedestal 111a is formed of metal or the like, it is easy to conduct heat from the hot plate 30. When the heat from the hot plate 30 is transmitted to the protrusion 111e, the portion of the boss 114d located around the protrusion 111e can be easily melted.

  Thus, not only the part which contacts the hot plate 30, but also the part located around the protrusion 111e can be melted, whereby the strength of the boss 114d after the thermal caulking process can be improved. FIG. 14 shows a configuration in which the protrusion 111e is not provided. If the protrusion 111e is not provided, the heat from the hot plate 30 is difficult to be transmitted to the region R2 shown in FIG. 14, and the region R2 may be difficult to melt. Moreover, when there are few fusion | melting parts, intensity | strength may fall.

  In the present embodiment, a protrusion 111e is provided in a portion corresponding to the region R2 in FIG. 14, and the boss 114d can be melted using the protrusion 111e. Thereby, all the parts to be melted of the boss 114d can be melted, and the strength of the boss 114d after the heat caulking process can be improved.

  Here, even in the configuration shown in FIG. 14, the heat of the hot plate 30 can be transmitted to the region R <b> 2 as long as the time for bringing the hot plate 30 into contact with the boss 114 d is secured. On the other hand, in this embodiment, by using the protrusion 111e, the heat of the hot plate 30 can be quickly transmitted to the portion of the boss 114d located around the protrusion 111e, and the time required for the heat caulking process is shortened. be able to.

  On the other hand, if the hot plate 30 and the boss 114d are formed in a complicated shape, the heat of the hot plate 30 can be easily transmitted to the boss 114d. However, in this case, the hot plate 30 and the boss 114d have a complicated shape. In this embodiment, only the protrusion 111e is provided on the pedestal 111a, and a simple configuration can be achieved.

  In the present embodiment, the heat plate 30 is brought into contact with the pedestal 111a to transfer the heat of the heat plate 30 to the protrusions 11e, but this is not restrictive. Specifically, the pedestal 111a can be heated in advance, or the pedestal 111a can be heated while the heat caulking process is performed. When the hot plate 30 is brought into contact with the pedestal 111a and the heat of the hot plate 30 is transmitted to the protrusion 111e, it takes time until the heat of the hot plate 30 is transferred to the protrusion 111e. Here, if the pedestal 111a is heated, the heat of the hot plate 30 is easily transmitted to the protrusion 111e, and the time required for the heat caulking process can be shortened.

  In the present embodiment, the protrusion 111e is formed along the through hole 111c, but the present invention is not limited to this. Specifically, the protrusion 111e can be formed at a position shifted from the through hole 111c. Even in this case, the same effect as in the present embodiment can be obtained. That is, compared with the case where the protrusion 111e is not provided, the boss 114d can be easily melted, and the strength of the boss 114d can be ensured.

  In the first and second embodiments, the current interruption mechanism using the pressure-sensitive member 116 is provided in the current path between the positive electrode terminal 110 and the positive electrode current collector 111, but the present invention is not limited to this. Specifically, in addition to the configuration of the first and second embodiments, or instead of the configuration of the first and second embodiments, the pressure sensitive member 116 is provided in the current path between the negative electrode terminal 120 and the negative electrode current collector 121. The current interruption mechanism used can be provided. That is, as the structure for electrically connecting the negative electrode terminal 120 and the negative electrode current collector 121, the structure for electrically connecting the positive electrode terminal 110 and the positive electrode current collector 111 described in the first and second embodiments can be used. . Thereby, the current path between the negative electrode terminal 120 and the negative electrode current collector 121 can be interrupted.

  A third embodiment of the present invention will be described. Here, the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The present embodiment relates to the structure at the connecting portion between the current collector holder 114 and the positive electrode current collector 111. Specifically, when the stress generated when the arm portion 111d of the positive electrode current collector 111 is bent acts on the boss 114d of the current collector holder 114, the structure of the boss 114d that can withstand this stress. It is about.

  FIG. 15 is an external view showing a structure in which the positive electrode current collector 111, the current collector holder 114, and the like are attached to the lid 10b. In this embodiment, as shown in FIG. 15, the positive electrode current collector 111 has a pair of arm portions 111d. Each arm portion 111d extends downward (Z direction) from the pedestal 111a. The power generation element 20 is disposed between the pair of arm portions 111d, and each arm portion 111d is fixed to the current collector foil 21a (see FIG. 4) exposed at the end of the power generation element 20.

  FIG. 16 is a diagram for explaining processing when the positive electrode current collector 111 is processed. FIG. 16 is a schematic diagram showing a positional relationship among the positive electrode current collector 111, the lid 10b, and the positive electrode terminal 110 when viewed from the direction of the arrow D1 shown in FIG.

  As described in the first embodiment, the boss 114 d of the current collector holder 114 is deformed by being applied with heat after being inserted into the through hole 111 c of the positive electrode current collector 111. Thereby, the boss 114d is formed in a shape along the through hole 111c. Thus, when performing the heat caulking process of the boss | hub 114d, as shown in FIG. 16, a pair of arm part 111d becomes an open shape. Specifically, the distance between the pair of arm portions 111d (interval in the X direction) widens toward the tip of the arm portion 111d.

  Thus, by making a pair of arm part 111d into the open shape, it can suppress that the jig | tool at the time of performing a heat caulking process interferes with the arm part 111d. After performing the heat caulking process, the pair of arm portions 111d can be shaped as shown in FIG. 15 by bending one arm portion 111d. Thereby, each arm part 111d can be fixed to the electric power generation element 20 after performing the heat caulking process of the boss | hub 114d.

  In the example shown in FIG. 16, only one arm portion 111d is bent, but a pair of arm portions 111d can be bent. That is, in a state where the pair of arm portions 111d are opened, the boss 114d is subjected to the thermal caulking process, and after the thermal caulking process, the pair of arm portions 111d can be bent in a direction approaching each other.

  In the present embodiment, the positive electrode current collector 111 has a pair of arm portions 111d, but the present invention is not limited to this. Specifically, as in the first embodiment, this embodiment can be applied even when the positive electrode current collector 111 has one arm portion 111d. Specifically, this embodiment can be applied when bending one arm portion 111d.

  When the arm portion 111d is bent, stress concentrates on the portion of the positive electrode current collector 111 in the region R3 shown in FIG. A region R3 illustrated in FIG. 16 is a base end portion of the arm portion 111d, and the arm portion 111d is bent using the base end portion as a reference. Here, as shown in FIG. 15, the boss 114 d of the current collector holder 114 is disposed at a position adjacent to the base end of the arm 111 d.

  For this reason, when the arm portion 111d is bent, the stress also acts on the boss 114d. As described in the first embodiment, the current collector holder 114 (boss 114d) is formed of a thermoplastic resin. For this reason, when a stress acts on the boss 114d, an excessive load is applied to the boss 114d.

  Therefore, in this embodiment, the strength of the boss 114d is improved by setting the shape of the boss 114d as described below. By improving the strength of the boss 114d, it is possible to prevent the boss 114d from being broken even when stress is concentrated on the boss 114d during bending of the arm portion 111d.

  FIG. 17 is a schematic view of a connection portion between the current collector holder 114 and the positive electrode current collector 111, and corresponds to a cross-sectional view taken along line A2-A2 of FIG. The through hole 111c formed in the base 111a of the positive electrode current collector 111 has a cylindrical region 111c3, a first tapered region 111c4, and a second tapered region 111c5.

  The cylindrical region 111c3 extends in a direction (Z direction) orthogonal to a plane (XY plane) where the pedestal 111a is located. One end of the cylindrical region 111c3 is connected to the upper surface of the pedestal 111a, and the other end of the cylindrical region 111c3 is connected to the first tapered region 111c4 and the second tapered region 111c5.

  The taper angle α of the first taper region 111c4 and the taper angle β of the second taper region 111c5 are different from each other. Specifically, the taper angle α is larger than the taper angle β. The taper angle α is an angle between a line (a dotted line shown in FIG. 17) obtained by extending the cylindrical region 111c3 and the first taper region 111c4. The taper angle β is an angle between a line obtained by extending the cylindrical region 111c3 and the second tapered region 111c5.

  Before the heat caulking process, the boss 114d is formed in a cylindrical shape. Specifically, the boss 114d is formed in a shape along the cylindrical region 111c3 of the through hole 111c. Further, the tip of the boss 114d protrudes from the through hole 111c. By subjecting the tip of the boss 114d to thermal caulking, as shown in FIG. 17, the boss 114d is formed in a shape along the through hole 111c (particularly, the tapered regions 111c4 and 111c5). That is, the boss 114d is in contact with the tapered regions 111c4 and 111c5 of the through hole 111c and has a tapered surface corresponding to the tapered regions 111c4 and 111c5.

  In the boss 114d after the heat caulking process, the diameter of the boss 114d increases from the base end portion 114d1 of the boss 114d toward the tip end portion 114d2. The diameter of the boss 114d is the length of the boss 114d in the X direction in FIG. In the portion corresponding to the cylindrical region 111c3 of the through hole 111c, the diameter of the boss 114d is constant.

  On the other hand, in the portion corresponding to the tapered regions 111c4 and 111c5 of the through hole 111c, the diameter of the boss 114d continuously increases from the base end portion 114d1 toward the tip end portion 114d2. The tip 114d2 of the boss 114d is located in the same plane as the lower surface (the lower surface shown in FIG. 17) of the pedestal 111a. That is, the tip 114d2 of the boss 114d does not protrude from the through hole 111c.

  As shown in FIG. 17, the cross-sectional shape of the boss 114d is asymmetric. Specifically, the tip end portion 114d2 of the boss 114d is displaced toward the arm portion 111d with respect to the base end portion 114d1 of the boss 114d. The distal end portion 114d2 includes a region facing the proximal end portion 114d1 in the Z direction. In other words, the distal end portion 114d2 extends in a direction closer to the arm portion 111d than the proximal end portion 114d1, and extends in a direction away from the arm portion 111d than the proximal end portion 114d1.

  By shifting the distal end portion 114d2 toward the arm portion 111d with respect to the base end portion 114d1, the cross-sectional area (in other words, volume) of the boss 114d can be increased on the arm portion 111d side, and the strength of the boss 114d can be increased. Can be improved. Specifically, in FIG. 18, the area of the region E1 of the boss 114d corresponding to the first tapered region 111c4 is larger than the area of the region E2 of the boss 114d corresponding to the second tapered region 111c5. Regions E1 and E2 are regions in which the diameter (length in the X direction) of the boss 114d is expanded by the tapered regions 111c4 and 111c5.

  By making the area of the region E1 larger than the area of the region E2, the strength of the region E1 can be made higher than the strength of the region E2. Since the region E1 is located closer to the arm portion 111d than the region E2, when bending the arm portion 111d, stress is more likely to concentrate in the region E1 than in the region E2. Therefore, by setting the strength of the region E1 higher than the strength of the region E2, the region E1 can withstand the stress generated during the bending process of the arm portion 111d.

  As described above, if the strength of the boss 114d can be improved, the boss 114d can withstand this stress even when stress is concentrated on the boss 114d during bending of the arm portion 111d. And it can prevent that the boss | hub 114d will fracture | rupture by the bending process of the arm part 111d.

  On the other hand, by making the area of the region E2 smaller than the area of the region E1, the material for forming the boss 114d can be reduced, and the cost can be reduced. As described above, the stress generated during bending of the arm portion 111d is unlikely to act on the region E2. For this reason, it is not necessary to make the area E2 equal to the area E1 and improve the strength of the area E2. Thus, the material for forming the boss 114d can be reduced by making the area of the region E2 smaller than the area of the region E1.

  FIG. 19 is a view as seen from the direction of the arrow D2 shown in FIG. In the present embodiment, as described above, the first taper region 111c4 is formed on the arm portion 111d side, and the second taper region 111c5 is formed on the side away from the arm portion 111d. That is, the first tapered region 111c4 is formed in the region F1 located on the arm portion 111d side with respect to the boundary line BL. A second taper region 111c5 is formed in a region F2 located on the opposite side of the boundary line BL from the arm portion 111d side.

  In the present embodiment, the through hole 111c is constituted by the two tapered regions 111c4 and 111c5, but is not limited thereto. For example, as shown in FIG. 20, the region in the circumferential direction of the through hole 111c can be divided into a plurality of regions F3 to F5, and the taper angles in the regions F3 to F5 can be made different from each other. FIG. 20 corresponds to FIG.

  In the regions F3 to F5, the region F3 is located closest to the arm portion 111d. For this reason, the taper angle of the region F3 can be maximized. Since the region F5 is farthest from the arm portion 111d, the taper angle of the region F5 can be minimized. The taper angle of the region F4 can be smaller than the taper angle of the region F3 and larger than the taper angle of the region F5.

  The taper angles of the regions F3 to F5 only need to satisfy the above-described magnitude relationship, and specific values can be set as appropriate. In the present embodiment, the region in the circumferential direction of the through hole 111c is divided into three regions F3 to F5, but the number of the divided regions can be set as appropriate.

  On the other hand, as shown in FIG. 21, the taper angle can be continuously changed in the circumferential direction of the through hole 111c. FIG. 21 corresponds to FIG. A point P1 shown in FIG. 21 is a position closest to the arm portion 111d. For this reason, the taper angle at the point P1 can be maximized. Further, a point P2 shown in FIG. 21 is a position farthest from the arm portion 111d. For this reason, the taper angle at the point P2 can be minimized. As the point P1 approaches the point P2, the taper angle can be continuously reduced.

  In the configuration shown in FIG. 17, the cylindrical region 111c3 is provided in the through hole 111c, but the cylindrical region 111c3 may be omitted. Specifically, as shown in FIG. 22, the through-hole 111c can be configured by only the tapered regions 111c4 and 111c5. FIG. 22 corresponds to FIG.

  In the present embodiment, the tapered region is formed in the through hole 111c, but the present invention is not limited to this. Specifically, as shown in FIG. 23, a through hole 111c can be formed. FIG. 23 corresponds to FIG. Similar to the present embodiment, the diameter r2 of the second region 111c2 is larger than the diameter r1 of the first region 111c1, and the second region 111c2 is shifted to the arm portion 111d side with respect to the first region 111c1.

  If the through hole 111c is formed as shown in FIG. 23, the boss 114d can be formed along the through hole 111c. Thereby, like the present embodiment, the strength of the boss 114d on the arm portion 111d side can be improved. Accordingly, when the arm portion 111d is bent, even if stress is concentrated on a part of the boss 114d (portion located on the arm portion 111d side), the boss 114d can withstand this stress.

  In the present embodiment, the positive electrode current collector 111 has been described. However, when the negative electrode current collector 121 has the same structure as that of the present embodiment, the present embodiment is applied to the negative electrode current collector 121. Can do. In the present embodiment, the structure described in the second embodiment can be employed. That is, the protrusion 111e described in the second embodiment can be provided to the through hole 111c described in the present embodiment.

  Embodiment 4 of the present invention will be described. Here, the same members as those described in the first and third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. This embodiment relates to the structure of the positive electrode current collector 111. Specifically, as in the third embodiment, the present invention relates to a structure for reducing stress acting on the boss 114d of the current collector holder 114 when the arm portion 111d of the positive electrode current collector 111 is bent.

  24 is an external view showing a structure in which the positive electrode current collector 111, the current collector holder 114, and the like are attached to the lid 10b, and corresponds to FIG. FIG. 25 is a view when seen from the direction of the arrow D3 shown in FIG. FIG. 26 is an enlarged view of a region R4 shown in FIG. In the present embodiment, as in the third embodiment, after the caulking process is performed on the boss 114d, the arm portion 111d of the positive electrode current collector 111 is bent.

  Here, a concave portion 111f is formed at the base end portion of the arm portion 111d to be bent. The recess 111f is formed along the proximal end portion of the arm portion 111d. In the present embodiment, after the heat caulking process of the boss 114d, only one of the pair of arm portions 111d is bent. For this reason, the recessed part 111f is formed only in the one arm part 111d bent.

  As shown in FIG. 25, the recess 111f is formed in the outer wall surface 111d1 of the arm 111d. The arm portion 111 d has an outer wall surface 111 d 1 and an inner wall surface 111 d 2, and the inner wall surface 111 d 2 is in contact with the power generation element 20.

  The recess 111f extends in the width direction (Y direction) of the arm portion 111d. That is, a recess 111f is formed from one end to the other end of the arm portion 111d in the Y direction. As shown in FIG. 25, by forming the recess 111f, the thickness of the portion of the arm 111d where the recess 111f is formed is thinner than the thickness of the portion where the recess 111f is not formed. The thickness here is the size of the arm portion 111d in the X direction.

  The recess 111f is formed by making the thickness of the portion where the recess 111f is formed (a part of the arm portion 111d) thinner than the thickness of the portion where the recess 111f is not formed (a portion of the arm portion 111d). Can bend easily. That is, when bending the arm portion 111d, the arm portion 111d can be easily bent.

  If the arm 111d is easily bent, the stress acting on the boss 114d of the current collector holder 114 can be reduced when the arm 111d is bent. Thereby, it can prevent that the boss | hub 114d will fracture | rupture by the stress which generate | occur | produces at the time of the bending process of the arm part 111d.

  In the present embodiment, the concave portion 111f is formed only in one arm portion 111d, but this is not restrictive. That is, when bending the pair of arm portions 111d, the recess portions 111f can be formed in the arm portions 111d. Thereby, both of the pair of arm portions 111d can be easily bent.

  In the present embodiment, the recess 111f is formed on the outer wall surface 111d1 of the arm 111d, but this is not a limitation. Specifically, the recess 111f can be formed in at least one of the outer wall surface 111d1 and the inner wall surface 111d2. In other words, the recess 111f can be formed on the inner wall surface 111d2, or the recess 111f can be formed on the outer wall surface 111d1 and the inner wall surface 111d2. Even if the recess 111f is formed in this way, the arm 111d can be easily bent as in the present embodiment.

  In the present embodiment, the recess 111f is formed from one end to the other end of the arm portion 111d in the Y direction, but this is not a limitation. Specifically, as shown in FIG. 27, a plurality of concave portions 111f can be formed in the arm portion 111d. Here, the plurality of recesses 111f are formed along a portion where the arm portion 111d is bent. The number of the recesses 111f and the size of each recess 111f can be set as appropriate based on the viewpoint that the arm portion 111d can be easily bent.

  The structure described in Embodiment 2 or Embodiment 3 can be combined with the structure described in this embodiment. When the structures described in the present embodiment and the third embodiment are combined, the stress acting on the boss 114d can be reduced when the arm portion 111d is bent while improving the strength of the boss 114d.

  In this embodiment, the positive electrode current collector 111 is described. However, when the negative electrode current collector 121 has the same structure as that of this embodiment, this embodiment is applied to the negative electrode current collector 121. can do. In this embodiment, the positive electrode current collector 111 has a pair of arm portions 111d. However, the present embodiment can be applied even to the positive electrode current collector 111 having one arm portion 111d. it can. That is, this embodiment can be applied when bending the arm portion 111d.

1: Secondary battery 10: Battery case 10a: Case body 10b: Lid 10c: Valve 10d: Injection port 10e, 10f: Through hole 11: Injection plug 110: Positive electrode terminal 111: Positive electrode collector 111a: Base 111b: Breaking portion 111c: Through hole 111d: Arm portion 112: External connection terminal 113: External insulating member 114: Current collector holder 114c: Leg portion 114d: Boss 115: Lead member 116: Pressure sensitive member (deformable member) 116a: Deformed portion 120: Negative electrode terminal 121: Negative electrode current collector 122: External connection terminal 123: External insulating member 124: Internal insulating member

Claims (16)

A power generation element for charging and discharging; and
A case for accommodating the power generation element in a sealed state;
A current collector housed in the case and electrically connected to the power generation element;
A deformable member that deforms in response to an increase in internal pressure of the case, and that breaks the mechanical connection with the current collector;
An electrode terminal protruding outside the case and electrically connected to the deformable member;
A lead member fixed to the deformable member and penetrating through the case and electrically connected to the electrode terminal;
A holder that is located between the lead member and the case, supports the current collector in a state of being fixed to the case, and is formed of an insulating and thermoplastic material, the current collector And a holder having a boss whose tip is formed along the outer surface of the current collector and in contact with the current collector without a gap ,
The secondary battery, wherein the lead member presses the holder against the case across the holder and the case. A power generation element for charging and discharging; and
A case for accommodating the power generation element in a sealed state;
A current collector housed in the case and electrically connected to the power generation element;
A deformable member that deforms in response to an increase in internal pressure of the case, and that breaks the mechanical connection with the current collector;
An electrode terminal protruding outside the case and electrically connected to the deformable member;
A holder that supports the current collector in a state of being fixed to the case, and is formed of an insulating and thermoplastic material, and passes through a through-hole formed in the current collector. A holder having a boss formed along the through hole and in contact with the current collector without a gap ;
The through hole is located on the outer edge side of the current collector from a portion of the current collector mechanically connected to the deformable member,
The through hole has a first region located on the base end side of the boss, and a second region located on the tip end side of the boss and having a width wider than the first region,
The secondary battery according to claim 1, wherein the boss is formed in a shape along the first region and the second region. A power generation element for charging and discharging; and
A case for accommodating the power generation element in a sealed state;
A current collector housed in the case and electrically connected to the power generation element;
A deformable member that deforms in response to an increase in internal pressure of the case, and that breaks the mechanical connection with the current collector;
An electrode terminal protruding outside the case and electrically connected to the deformable member;
A holder that supports the current collector in a state of being fixed to the case, and is formed of an insulating and thermoplastic material, and passes through a through-hole formed in the current collector. A holder having a boss formed along the through hole and in contact with the current collector without a gap ;
The through hole is located on the outer edge side of the current collector from a portion of the current collector mechanically connected to the deformable member,
The current collector has a pedestal provided with the through-hole, and an arm portion that extends from the outer edge of the pedestal toward the power generation element in a bent state, and is fixed to the power generation element.
The thickness of the boss increases continuously or stepwise from the base end of the boss toward the tip of the boss,
The secondary battery is characterized in that a distal end portion of the boss is shifted toward the arm portion with respect to a proximal end portion of the boss. A power generation element for charging and discharging; and
A case for accommodating the power generation element in a sealed state;
A current collector housed in the case and electrically connected to the power generation element;
A deformable member that deforms in response to an increase in internal pressure of the case, and that breaks the mechanical connection with the current collector;
An electrode terminal protruding outside the case and electrically connected to the deformable member;
A holder that supports the current collector in a state of being fixed to the case, and is formed of an insulating and thermoplastic material, and passes through a through-hole formed in the current collector. A holder having a boss formed along the through hole and in contact with the current collector without a gap ;
The through hole is located on the outer edge side of the current collector from a portion of the current collector mechanically connected to the deformable member,
The current collector includes a pedestal provided with the through hole, and an arm portion that extends from the outer edge of the pedestal toward the power generation element in a bent state, and is fixed to the power generation element.
The secondary battery according to claim 1, wherein the arm portion has a concave portion in a bent portion. A power generation element for charging and discharging; and
A case for accommodating the power generation element in a sealed state;
A current collector housed in the case and electrically connected to the power generation element;
A deformable member that deforms in response to an increase in internal pressure of the case, and that breaks the mechanical connection with the current collector;
An electrode terminal protruding outside the case and electrically connected to the deformable member;
A holder that supports the current collector in a state of being fixed to the case and is formed of an insulating and thermoplastic material, the holder passing through the current collector, and a distal end portion of the current collector. And a holder having a boss formed in contact with the current collector without a gap ,
The secondary battery according to claim 1, wherein the current collector has a protrusion extending toward the tip end side of the boss along the boss. The lead member is fixed to the deformable member, penetrates the case, and is electrically connected to the electrode terminal.
The secondary battery according to claim 2, wherein the holder is located between the lead member and the case.   The secondary battery according to claim 6, wherein the lead member presses the holder against the case across the holder and the case. The boss penetrates a through hole formed in the current collector, and is formed along the through hole.
The said through-hole is located in the outer edge side of the said electrical power collector rather than the part mechanically connected with the said deformation member among the said electrical power collectors, The Claim 1 or 5 characterized by the above-mentioned. Secondary battery. The through hole has a first region located on the base end side of the boss, and a second region located on the tip end side of the boss and having a width wider than the first region,
The secondary battery according to claim 8, wherein the boss is formed in a shape along the first region and the second region. The boss has a tapered surface that expands toward the tip of the boss,
The taper angle of the first region located on the arm portion side in the tapered surface is larger than the taper angle of the second region located on the side away from the arm portion. Secondary battery.   The secondary battery according to claim 4, wherein the concave portion extends in a direction along a bent portion of the arm portion.   The secondary battery according to any one of claims 3, 4, 10, and 11, wherein the current collector has the arm portion at a position sandwiching the power generation element.   The secondary battery according to any one of claims 2 to 4, and 8 to 12, wherein a tip end portion of the boss is located in a plane including an end portion of the through hole. The current collector has a through hole through which the boss passes,
The secondary battery according to claim 5, wherein the protrusion is formed to be continuous with the through hole.   The secondary battery according to claim 1, wherein the case is formed in a shape along a rectangular parallelepiped. A method for manufacturing a secondary battery, comprising:
The secondary battery is
A power generation element for charging and discharging; and
A case for accommodating the power generation element in a sealed state;
A current collector housed in the case and electrically connected to the power generation element;
A deformable member that deforms in response to an increase in internal pressure of the case, and that breaks the mechanical connection with the current collector;
An electrode terminal protruding outside the case and electrically connected to the deformable member;
A holder formed of an insulating material and supporting the current collector in a state of being fixed to the case,
The current collector has a protrusion extending toward the tip end side of the boss along a boss formed on the holder ,
Before the Kibo scan is passed through the current collector, by thermal caulking process to the distal end of the boss that protrudes from the current collector, formed along the distal end portion of the boss to the outer surface of the current collector And
A method of manufacturing a secondary battery, wherein, in the thermal caulking process, heat is also applied to the protrusions of the current collector.

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