JP2015095404A - Power storage element and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element in which high efficiency resistance-welding is possible between an electrode laminate and a collector.SOLUTION: In a power storage element 10 including an electrode body 140 formed by laminating a positive electrode 141, a negative electrode 142 and a separator 143, a positive electrode terminal 200, and a positive electrode collector 120 for connecting the positive electrode terminal 200 and the electrode body 140 electrically, the power storage element 10 further includes a conjugate 180 arranged between the electrode body 140 and the positive electrode collector 120, and joined thereto, and an insulation member 190 arranged between the electrode body 140 and the positive electrode collector 120. The conjugate 180 includes a through portion 183 penetrating the insulation member 190.

Description

  The present invention relates to an energy storage device including an electrode body, an electrode terminal, and an electrode body and a current collector connected to the electrode terminal.

  The shift from gasoline cars to electric cars has become important as a global environmental problem. For this reason, use of electrical storage elements such as nonaqueous electrolyte secondary batteries as a power source for electric vehicles has been studied.

  Such a power storage element includes, for example, an electrode body in which a positive electrode and a negative electrode, and a separator disposed between the positive electrode and the negative electrode are stacked. At each end of the positive electrode and the negative electrode of the electrode body, an electrode laminated portion is formed by laminating a metal foil portion not coated with an active material, and the electrode laminated portion is made of a metal called a current collector. The members are connected. In addition, an electrode terminal which is a positive electrode terminal or a negative electrode terminal is connected to the current collector, and power from the electrode body is supplied to a load such as a motor via the electrode terminal.

  As a technique for joining the electrode laminate and the current collector in the power storage device having the above-described structure that requires high output, resistance welding can be cited in which a current is passed through the contact portion between the electrode laminate and the current collector to melt it. .

  Patent Document 1 discloses a battery structure in which an electrode stack portion of an electrode body and a current collecting member are joined by resistance welding.

  FIG. 7 is an enlarged exploded cross-sectional view of the resistance welding portion of the electricity storage device described in Patent Document 1. In the conventional power storage device shown in the figure, the protrusion 580 provided on the surface of the negative electrode current collector 530, the negative electrode core exposed portion 541 corresponding to the upper electrode laminated portion, and the negative electrode current collector receiving component 545 Are sandwiched between both electrode rods of a resistance welding apparatus and resistance welded. At this time, the negative electrode current collector 530, the negative electrode core body exposed portion 541, and the negative electrode current collector receiving component 545 are in pressure contact with each other, so that the heat weldability having an opening 590A as an insulating seal material around the protrusion 580. A resin tape 590 is disposed. According to this configuration, since the resistance welding current flowing through the protrusion 580, the negative electrode core exposed portion 541, and the negative electrode current collector receiving component 545 passes through the opening 590A, the reactive current not involved in welding is reduced. Resistance welding can be performed efficiently and firmly. Further, since the periphery of the resistance welding portion is surrounded by the heat welding resin tape 590, the sputtered foreign matter generated during the resistance welding is captured by the heat welding resin tape 590 and is not scattered outside. Therefore, it is said that a highly reliable sealed battery with few internal short circuits is obtained.

Japanese Patent No. 5100281

  However, in the resistance welding structure of the electricity storage element described in Patent Document 1, the protrusion 580 and the heat-welding resin tape 590 are not in close contact with each other. Therefore, there is a possibility that the negative electrode current collector 530 and the negative electrode core exposed portion 541 are in contact with each other except for the protrusion 580, and a current path that does not include the protrusion 580 is formed.

  This invention is made | formed in view of the said subject, and it aims at providing the electrical storage element which can perform highly efficient resistance welding of an electrode laminated part and a collector, and its manufacturing method.

  In order to achieve the above object, an energy storage device according to one embodiment of the present invention includes an electrode body formed by stacking a positive electrode, a negative electrode, and a separator, an electrode terminal, and the electrode terminal and the electrode body electrically A power storage element including a current collector to be connected, wherein the power storage element is further disposed between the electrode body and the current collector and joined to the electrode body and the current collector A body and an insulating member disposed between the electrode body and the current collector, and the joined body includes a penetrating portion penetrating the insulating member.

  According to the above configuration, since the joined body that joins the electrode body and the current collector includes the penetrating portion that penetrates the insulating member disposed between the electrode body and the current collector, the electrode body and the current collector. The energization path at the time of resistance welding is limited to the through portion, and highly efficient resistance welding by current concentration becomes possible.

  The insulating member may be disposed so as to cover a surface of the current collector facing the electrode body.

  Thereby, since the surface which opposes the electrode body of a collector is covered with the insulating member, it can prevent that a collector and an electrode body contact directly in parts other than a joined body.

  The penetrating portion may be in contact with the insulating member.

  According to this, since the penetrating portion for connecting the current collector and the electrode body is in contact with the insulating member, it is possible to reduce the dispersion of current during resistance welding.

  The joined body is further disposed on the electrode body side of the insulating member, and is disposed on the current collector side of the insulating member, the electrode body side joint portion joined to the electrode body, and the current collector. And a current collector side joint that sandwiches the insulating member with the electrode body side joint, and the through portion connects the electrode body side joint and the current collector side joint. .

  According to this, since the joined body sandwiches the insulating member, it is possible to prevent the insulator from dropping from the joined body. Therefore, scattering of the captured sputtered foreign matter can be prevented.

  The joined body is further disposed on the electrode body side of the insulating member, and is disposed on the current collector side of the insulating member, the electrode body side joint portion joined to the electrode body, and the current collector. A current collector-side joined portion, the through portion connects the electrode body-side joined portion and the current collector-side joined portion, and the electrode body is formed by laminating the positive electrode, the separator, and the negative electrode. A laminated main body part, and an exposed part in which the positive electrode or the negative electrode is exposed from the laminated main body part and joined to the electrode body side joint part, and the insulating member includes the laminated main body part and the exposed part. An insulating inclined portion that is inclined toward the current collector side with respect to the formation surface direction of the insulating member may be provided in a region facing the boundary.

  During resistance welding, if the separator bites between the welding electrode and the current collector, the welding device tries to flow a predetermined welding current in a state where the resistance between the welding electrodes is increased. Excessive voltage is applied between them. At this time, if the caught separator comes off due to vibration or the like, an abnormal current flows in a state where the resistance between the welding electrodes is rapidly reduced. The abnormal current may cause the foil constituting the positive electrode or the negative electrode to melt. On the other hand, according to the above configuration, the insulating inclined portion can prevent the separator from being caught between the welding electrode and the current collector, so that fusing of the foil due to the abnormal current can be avoided.

  The joined body and the insulating member may be joined by caulking.

  According to this, since the joined body and the insulating member are mechanically firmly joined, it is possible to prevent the insulator from dropping from the joined body.

  The insulating member may be integrally formed with the joined body by resin insert molding.

  According to this, since the joined body and the insulating member are firmly joined by resin molding, it is possible to prevent the insulator from dropping from the joined body.

  The joined body may be integrally formed with the current collector.

  According to this, since the joined body is integrally formed with the current collector, the process of fixing and arranging the insulating member between the electrode body and the current collector is simplified.

  In order to achieve the above object, a method for manufacturing a power storage device according to one embodiment of the present invention includes an electrode body formed by stacking a positive electrode, a negative electrode, and a separator, an electrode terminal, the electrode terminal, and the electrode. A power storage element manufacturing method comprising a current collector for electrically connecting a body, wherein a connecting portion connecting a first bonding portion and a second bonding portion is passed through an insulating member, and the electrode body, The first joint portion, the connection portion, the second joint portion, and the current collector are joined.

  According to this, since the insulating member is arranged around the connection portion, the energization path when the electrode body and the current collector are resistance-welded is limited to the connection portion, and high-efficiency resistance welding by current concentration is performed. it can.

  According to the electricity storage device of the present invention, since the joined body that joins the electrode body and the current collector includes the penetrating portion that penetrates the insulating member disposed between the electrode body and the current collector, the electrode body The energization path when the current collector and the current collector are resistance-welded is limited, and high-efficiency resistance welding by current concentration can be performed.

It is a perspective view which shows the outline | summary of the external appearance and internal structure of the electrical storage element which concerns on Embodiment 1 of this invention. It is a perspective view which shows each component with which the main body of the container of the electrical storage element which concerns on Embodiment 1 of this invention is isolate | separated, and an electrical storage element is provided. 4 is a U-U ′ cross-sectional view of the electrode body according to Embodiment 1. FIG. It is V-V 'sectional drawing of the electrode body showing the joining state of the conjugate | zygote which concerns on Embodiment 1 of this invention, and a collector. It is V-V 'sectional drawing of the electrode body showing the junction structure of the positive electrode laminated part which concerns on Embodiment 1 of this invention, and a positive electrode electrical power collector. It is V-V 'sectional drawing of the electrode body showing the junction structure of the positive electrode laminated part which concerns on the modification 1 of Embodiment 1 of this invention, and a positive electrode electrical power collector. It is V-V 'sectional drawing of the electrode body showing the junction structure of the positive electrode laminated part which concerns on the modification 2 of Embodiment 1 of this invention, and a positive electrode electrical power collector. It is V-V 'sectional drawing of the electrode body showing the junction structure of the positive electrode laminated part which concerns on the modification 3 of Embodiment 1 of this invention, and a positive electrode electrical power collector. It is V-V 'sectional drawing of the electrode body showing the junction structure of the positive electrode laminated part which concerns on the modification 4 of Embodiment 1 of this invention, and a positive electrode electrical power collector. It is V-V 'sectional drawing of the electrode body showing the junction structure of the positive electrode laminated part which concerns on Embodiment 2 of this invention, and a positive electrode electrical power collector. 6 is an enlarged exploded cross-sectional view of a resistance welded portion of a power storage element described in Patent Literature 1. FIG.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each figure is a schematic diagram and is not necessarily illustrated exactly.

  The embodiment described below shows a specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, order of production steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

(Embodiment 1)
[Basic structure of energy storage device]
First, a battery is taken as an example of a power storage element, and a general description of the power storage element 10 according to Embodiment 1 will be given with reference to FIGS.

  FIG. 1 is a perspective view showing an outline of an external appearance and an internal structure of a power storage device according to Embodiment 1 of the present invention. In addition, the figure is a figure which saw through the container inside. FIG. 2 is a perspective view showing each component included in the power storage element by separating the main body of the container of the power storage element according to the first embodiment. FIG. 3 is a U-U ′ sectional view of the electrode body according to the first embodiment.

  The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. Examples of the non-aqueous electrolyte secondary battery include a lithium ion secondary battery in which the positive electrode active material is a lithium transition metal oxide such as lithium cobaltate and the negative electrode active material is a carbon material. The power storage element 10 is a secondary battery used in, for example, a hybrid electric vehicle (HEV) that charges and discharges at a high rate cycle. In addition, the electrical storage element 10 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it.

  As shown in FIG. 1, the electricity storage device 10 includes a battery container, a positive electrode terminal 200, and a negative electrode terminal 300. The battery container includes a casing main body 111 having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid 110 that closes an opening of the casing main body 111. In addition, the battery container has a structure in which after the electrode body 140 and the like are accommodated therein, the lid body 110 and the housing body 111 are welded or the like to seal the inside.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 140, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 140. That is, the positive electrode terminal 200 and the negative electrode terminal 300 are metal electrode terminals for leading the electricity stored in the electrode body 140 to the external space of the power storage element 10. The electrode body 140 is a metal electrode terminal for introducing electricity into the internal space of the electricity storage element 10 in order to store electricity.

  The positive electrode terminal 200 and the negative electrode terminal 300 are attached to the lid body 110 disposed above the electrode body 140. Specifically, as shown in FIG. 2, the positive electrode terminal 200 has a protruding portion 210 inserted into the through hole 110 a of the lid body 110 and the through hole 121 a of the positive electrode current collector 120, and is caulked. Along with the current collector 120, the lid 110 is fixed. Similarly, in the negative electrode terminal 300, the protruding portion 310 is inserted into the through hole 110 b of the lid body 110 and the through hole 131 a of the negative electrode current collector 130 and caulked, so that the lid body 110 together with the negative electrode current collector 130 is inserted. Fixed to. In addition, although packing etc. are also arrange | positioned, it abbreviate | omits and shows in the same figure.

  An electrode body 140 is accommodated inside the battery container, and a positive electrode current collector 120 and a negative electrode current collector 130 are further disposed. In addition, although liquid, such as electrolyte solution, may be enclosed in the inside of a battery container, illustration of the said liquid is abbreviate | omitted.

  The positive electrode current collector 120 is disposed between the electrode body 140 and the inner wall of the battery container, and has electrical conductivity and rigidity that are electrically connected to the positive electrode terminal 200 and the positive electrode laminate portion 141A of the electrode body 140. It is a member. Note that the positive electrode current collector 120 is made of aluminum or an aluminum alloy, for example, like the positive electrode base foil of the electrode body 140. In the present embodiment, positive electrode current collector 120 and positive electrode laminated portion 141A are joined by resistance welding.

  The negative electrode current collector 130 is disposed between the electrode body 140 and the inner wall of the battery container, and has electrical conductivity and rigidity that are electrically connected to the negative electrode terminal 300 and the negative electrode laminate portion 142B of the electrode body 140. It is a member. Note that the negative electrode current collector 130 is formed of, for example, copper or a copper alloy, similarly to the negative electrode base foil of the electrode body 140. In the present embodiment, negative electrode current collector 130 and negative electrode laminated portion 142B are joined by resistance welding.

  The electrode body 140 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. Specifically, as shown in FIGS. 2 and 3, the electrode body 140 is formed by laminating a layered structure in which a separator is sandwiched between a negative electrode and a positive electrode so that the whole becomes an oval shape. It is formed by turning. In FIG. 2, the electrode body 140 has an oval shape, but may have a circular shape or an oval shape. Further, the shape of the electrode body 140 is not limited to the winding type, and may be a shape in which flat plate plates are laminated. A detailed laminated structure of the electrode body 140 will be described with reference to FIG. FIG. 3 is a view of the U-U ′ cross section of the electrode body 140 shown in FIG. 1 as viewed from the Z-axis direction.

  As shown in FIG. 3, the electrode body 140 includes a positive electrode 141 having an active material layer, a separator 143, a negative electrode 142 having an active material layer formed thereon, and a stacked portion 140C in which a separator 143 is stacked in this order, A positive electrode laminate 141A in which a positive electrode 141 in which no material layer is formed is laminated, and a negative electrode laminate 142B in which a negative electrode 142 in which no active material layer is formed is laminated. As shown in FIG. 2, the positive electrode 141 and the negative electrode 142 are wound while being shifted from each other in the direction of the winding axis (in this embodiment, a virtual axis parallel to the X-axis direction) via the separator 143. Yes. In other words, the positive electrode 141 and the negative electrode 142 have the positive electrode stacking portion 141 </ b> A and the negative electrode stacking portion 142 </ b> B that are portions where the active material layer is not formed at the edge portions in the shifted directions.

In addition, as a positive electrode active material contained in the active material layer which the positive electrode 141 has, for example, LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more selected from Fe, Ni, Mn, Co, etc.) Polyanion compounds such as transition metal elements), spinel compounds such as lithium titanate and lithium manganate, LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), etc. Lithium transition metal oxide or the like can be used.

Examples of the negative electrode active material contained in the active material layer of the negative electrode 142 include lithium metal, lithium alloys (lithium-aluminum, lithium-silicon, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium- Lithium metal-containing alloys such as gallium and wood alloys), alloys capable of occluding and releasing lithium, and carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.) , Metal oxides, lithium metal oxides (such as Li ₄ Ti ₆ O ₁₂ ), and polyphosphoric acid compounds.

  The positive electrode 141 has a positive electrode laminate portion 141A at one end in the winding axis direction (end portion in the X-axis positive direction). Further, the negative electrode 142 has a negative electrode stacking portion 142B at the other end in the winding axis direction (end portion in the X-axis negative direction). That is, the positive electrode laminate portion 141A is formed by the exposed metal foil layer of the positive electrode 141, and the negative electrode laminate portion 142B is formed by the exposed metal foil layer of the negative electrode 142.

  In addition, the thickness of the metal foil of the positive electrode 141 and the metal foil of the negative electrode 142 is, for example, one of values of 5 μm to 20 μm. Moreover, these metal foils form, for example, the positive electrode stacking portion 141A and the negative electrode stacking portion 142B by stacking 40 or less sheets such as 30 sheets.

  The positive electrode current collector 120 is joined to the surface of the positive electrode laminate portion 141A in the region R1 shown in FIG. 2, and the negative electrode current collector 130 is joined to the surface of the negative electrode laminate portion 142B in the region Q1 shown in FIG. Are joined. Further, the electrode body 140 includes a cover 145A that protects the positive electrode stacking portion 141A that is bonded to the back surface of the positive electrode stacking portion 141A in the region R1. In addition, the electrode body 140 includes a cover 145B that protects the negative electrode laminate portion 142B that is bonded to the back surface of the negative electrode laminate portion 142B in the region Q1.

  The positive electrode laminate portion 141A and the cover 145A are resistance-welded to the positive electrode current collector 120 via a joined body described in FIG. 4 and the subsequent drawings, and similarly, the negative electrode laminate portion 142B and the cover 145B are described in FIG. The negative electrode current collector 130 is resistance-welded through the joined body.

[Joint structure of joined body and current collector]
FIG. 4 is a VV ′ cross-sectional view of the electrode body showing a joined state between the joined body and the current collector according to Embodiment 1 of the present invention. The figure is a view of the VV ′ cross section (cut surface in the Y direction) of the joined body 180 of the electrode body 140 and the positive electrode current collector 120 shown in FIG. 1 as viewed from the X-axis direction. As shown in the figure (left), the positive electrode current collector 120 is joined to the outer peripheral surface of the positive electrode laminate portion 141A in a wound state, and the cover 145A is joined to the inner peripheral back surface of the positive electrode laminate portion 141A. Yes. Specifically, in the joining region 170, the positive electrode laminate 141A, the cover 145A, and the positive electrode current collector 120 are joined by resistance welding.

  More specifically, in the junction region 170, the power storage element 10 includes the positive electrode stacking portion 141 </ b> A and the positive electrode current collector 120 disposed between the positive electrode stacking portion 141 </ b> A and the positive electrode current collector 120 of the electrode body 140. A joined body 180 to be joined, and an insulating member 190 disposed between the positive electrode laminate portion 141A and the positive electrode current collector 120 are provided. Moreover, the joined body 180 includes a through portion (shown in FIG. 5A) that penetrates the insulating member 190.

  The joined body 180 is made of aluminum or an aluminum alloy, for example, like the positive electrode base material foil of the electrode body 140 and the positive electrode current collector 120.

  The insulating member 190 is a layered member extending in the X direction and the Z direction in FIG. 4. For example, the insulating member 190 is integrally formed with the joined body 180 by insert molding, and is insulatively bonded to the joined body 180. It is a material.

  As described above, by disposing the insulating member 190 around the through portion, the energization path when the positive electrode laminate portion 141A and the positive electrode current collector 120 are resistance-welded is limited to the through portion, and due to current concentration. Highly efficient resistance welding is possible. Moreover, since the welding current value can be set small by eliminating the reactive current due to the current concentration, the risk of occurrence of spatter foreign matter can be reduced. Furthermore, since the welding conditions become weak, the consumption of the welding electrode on the welding apparatus side is reduced, and the running cost for the electrode can be suppressed.

  Note that, from the viewpoint of suppressing spatter foreign matter, it is preferable that a protrusion is formed on the surface of the insulating member 190 as shown in FIG. The protrusion is, for example, an annular convex portion formed so as to surround the joined body 180 when viewed from the Y-axis direction. With this projection structure, it is possible to prevent the sputtered foreign matter from moving into the electrode body 140.

  On the other hand, in the resistance welding structure of the electricity storage element described in Patent Document 1, the protrusion 580 and the insulating seal material are not in close contact with each other, and the negative electrode current collector 530 and the negative electrode core exposed portion are disposed on the outer periphery of the insulating seal material. 541 is facing. As a result, the negative electrode current collector 530 and the negative electrode core body exposed portion 541 are in contact with each other except for the protrusions 580, and there is a possibility that a current path not via the protrusions 580 may be formed. The insulating sealing material is a heat-welding resin tape or an insulating tape with a paste, and is not integrated with the current collector. Therefore, the positional relationship between the insulating sealing material and the protrusion 580 is not constant, and the alignment process during resistance welding becomes complicated. Furthermore, since the insulating sealing material is made of the tape, the insulating sealing material may be peeled off from the negative electrode current collector 530. When the insulating sealing material is peeled off from the negative electrode current collector 530, the foreign matter captured in the inner region of the insulating sealing material is dispersed, and the negative electrode current collector 530 and the negative electrode core exposed portion 541 are short-circuited except at the protrusion 580. There is a possibility that. On the other hand, in the electricity storage device according to the present embodiment, the current collector and the insulating member are structurally (mechanically) joined by caulking bonding or insert molding, so that the insulating member is on the current collector. It is firmly fixed to. Therefore, foreign matter is not dispersed.

  Hereinafter, a specific structure of the joined body 180 according to the present embodiment will be described.

  FIG. 5A is a V-V ′ sectional view of an electrode body showing a joint structure between the positive electrode stacking portion and the positive electrode current collector according to Embodiment 1 of the present invention. The joined body 180 shown in the figure includes an electrode body side joint portion 181 joined to the positive electrode laminate portion 141A, a current collector side joint portion 182 that sandwiches the insulating member 190 between the electrode body side joint portion 181 and the insulating member. Penetrating part 183. The electrode body side joint portion 181 is disposed on the electrode body 140 side (positive electrode laminate portion 141A side) of the insulating member 190. The positive electrode laminate portion 141 </ b> A is an exposed portion where the positive electrode 141 is exposed and is joined to the electrode body side joint portion 181. The current collector-side joint 182 is disposed on the positive electrode current collector 120 side of the insulating member 190 and is joined to the positive electrode current collector 120. The penetrating portion 183 connects the electrode body side joint portion 181 and the current collector side joint portion 182. The above structure is formed, for example, by insert-molding an insulating member 190 made of a resin material into the joined body 180.

  According to the above configuration, since the joined body 180 sandwiches the insulating member 190, the insulating member 190 can be prevented from falling off from the joined body 180. That is, the insulating member 190 and the joined body 180 are integrated. Therefore, since the positional relationship between the insulating member 190 and the joined body 180 to be resistance-welded is constant, the alignment process at the time of resistance welding is simplified. Further, since the joined body 180 mechanically sandwiches the insulating member 190, the insulating member 190 does not come off from the joined body 180, and as a result, the captured sputtered foreign matter does not scatter.

  The cover 145A, the positive electrode laminate portion 141A, the joined body 180, and the positive electrode current collector 120 are in a state of resistance welding. Specifically, the welding current is supplied via the joined body 180 between the welding electrodes 401 and 402 in the direction in which the positive electrode stacking portion 141A, the cover 145A, and the positive electrode current collector 120 are stacked. The positive electrode stacking portion 141A, the cover 145A, and the positive electrode current collector 120 are joined. As a result, the positive electrode stacking portion 141A and the positive electrode current collector 120 are electrically connected.

  Further, the penetrating portion 183 is in contact with the insulating member 190. Thereby, it can reduce that the current path at the time of resistance welding disperses | distributes other than the penetration part 183. FIG.

  The insulating member 190 is disposed so as to cover the surface of the positive electrode current collector 120 that faces the positive electrode stacking portion 141A. Thereby, it is possible to prevent the positive electrode current collector 120 and the electrode body 140 from coming into direct contact at a portion other than the joined body 180. Therefore, highly efficient resistance welding by current concentration becomes possible.

  Further, the shape of the joined body 180 in the joining region 170 is not limited to the shape described in FIG. 5A.

  FIG. 5B is a V-V ′ cross-sectional view of the electrode body showing a joint structure between the positive electrode stacking portion and the positive electrode current collector according to Modification 1 of Embodiment 1 of the present invention. The structure of the resistance welded portion shown in the figure is different from that shown in FIG. 5A only in that the positive electrode current collector and the joined body are integrated. The description of the same points as the structure of the resistance weld shown in FIG. 5A will be omitted, and only different points will be described below. In the structure of the resistance welding part according to this modification, the joined body formed on the positive electrode current collector 121 is formed integrally with the current collector. The structure shown in FIG. 5B is formed, for example, by insert-molding an insulating member 190 made of a resin material into a positive electrode current collector 121 having a current collector base, a penetrating portion, and an electrode body side joint portion. . With the above structure, since the positive electrode current collector 121 and the insulating member 190 are firmly bonded, it is possible to prevent the insulating member 190 from dropping from the positive electrode current collector 121. Further, since the joined body is integrally formed with the current collector, the process of fixing and arranging the insulating member 190 between the electrode body 140 and the positive electrode current collector 121 is simplified. Further, since the positive electrode current collector 121 sandwiches the insulating member 190, the insulating member 190 does not come off from the positive electrode current collector 121, and as a result, the captured sputtered foreign matter does not scatter.

  FIG. 5C is a V-V ′ cross-sectional view of an electrode body showing a joint structure between a positive electrode stacking portion and a positive electrode current collector according to Modification 2 of Embodiment 1 of the present invention. The structure of the resistance welded portion shown in the figure is different from that shown in FIG. 5B only in the coupling form of the positive electrode current collector and the joined body. The description of the same points as the structure of the resistance weld shown in FIG. 5B will be omitted, and only different points will be described below. In the structure of the resistance welded portion according to this modification, the joined body is integrally formed with the current collector. The structure shown in FIG. 5C is insulated from the positive electrode current collector 122 by, for example, caulking the electrode body side joint portion of the positive electrode current collector 122 having the current collector base, the penetrating portion, and the electrode body side joint portion. The member 190 is coupled. With the above structure, since the positive electrode current collector 122 and the insulating member 190 are firmly bonded, it is possible to prevent the insulating member 190 from dropping from the positive electrode current collector 122. Further, since the joined body is integrally formed with the current collector, the process of fixing and arranging the insulating member 190 between the electrode body 140 and the positive electrode current collector 122 is simplified. In addition, since the positive electrode current collector 122 sandwiches the insulating member 190, the insulating member 190 does not come off from the positive electrode current collector 122, and as a result, the captured sputtered foreign matter does not scatter.

  FIG. 5D is a V-V ′ cross-sectional view of the electrode body showing a joint structure between the positive electrode stacking portion and the positive electrode current collector according to Modification 3 of Embodiment 1 of the present invention. The structure of the resistance welded portion shown in the figure is different from that shown in FIG. 5B in that the insulating member 190 is not sandwiched between the joined bodies. The description of the same points as the structure of the resistance weld shown in FIG. 5B will be omitted, and only different points will be described below. In the structure of the resistance welded portion according to this modification, for example, by pressing from the back surface (lower surface) of the positive electrode current collector 123 toward the front surface (upper surface), protrusions are formed on the surface. The protrusion does not sandwich the insulating member 190, but the positive electrode current collector 123 is insert-molded with an insulating member 190 made of a resin material. With the above structure, since the positive electrode current collector 123 and the insulating member 190 are in close contact with each other, the insulating member 190 can be prevented from falling off from the positive electrode current collector 123. Further, since the joined body is integrally formed with the current collector, the process of fixing and arranging the insulating member 190 between the electrode body 140 and the positive electrode current collector 123 is simplified.

  FIG. 5E is a V-V ′ cross-sectional view of an electrode body showing a joint structure between a positive electrode stacking part and a positive electrode current collector according to Modification 4 of Embodiment 1 of the present invention. The structure of the resistance welded portion shown in the figure is different from that shown in FIG. 5A only in the coupling form of the positive electrode current collector and the joined body. The description of the same points as the structure of the resistance weld shown in FIG. 5A will be omitted, and only different points will be described below. In the structure of the resistance welded portion according to this modification, the joined body 185 includes a current collector side joint portion 187 that sandwiches the insulating member 190 between the electrode body side joint portion 186 joined to the positive electrode laminate portion 141A and the electrode body side joint portion 186. And a penetrating portion 188 penetrating the insulating member 190. The electrode body side joining portion 186 is disposed on the electrode body 140 side (positive electrode laminated portion 141A side) of the insulating member 190. In the structure shown in FIG. 5E, for example, the joined body 185 and the insulating member 190 are coupled by caulking the electrode body side joining portion 186. According to the above structure, since the joined body 185 sandwiches the insulating member 190, the insulating member 190 can be prevented from falling off from the joined body 185. That is, the insulating member 190 and the joined body 185 are integrated. Therefore, since the positional relationship between the insulating member 190 and the joined body 185 to be resistance-welded is constant, the alignment process at the time of resistance welding is simplified. Further, since the joined body 185 sandwiches the insulating member 190, the insulating member 190 does not come off from the joined body 185, and as a result, the captured sputtered foreign matter does not scatter.

  Although not shown in FIG. 4 and FIGS. 5A to 5E, the bonding mode between the negative electrode stacking portion 142B and the negative electrode current collector 130 is also the bonding mode between the positive electrode stacking portion 141A and the positive electrode current collector 120 described above. The same effect is produced.

(Embodiment 2)
The electricity storage device according to the present embodiment has a structure that prevents the separator from being caught between the welding electrodes. Hereinafter, description of the same basic configuration as that of power storage element 10 according to Embodiment 1 will be omitted, and description will be made focusing on different portions as the structure of bonding region 170.

[Joint structure of joined body and current collector]
FIG. 6 is a VV ′ cross-sectional view of an electrode body showing a joint structure between the positive electrode stacking portion and the positive electrode current collector according to Embodiment 2 of the present invention. The figure is a view of the VV ′ cross section (cut surface in the Y direction) of the joined body 180 of the electrode body 140 and the positive electrode current collector 120 shown in FIG. 1 as viewed from the X-axis direction. The joined body 180 shown in the figure has the structure shown in FIG. 5A. That is, the joined body 180 includes an electrode body side joining portion 181 joined to the positive electrode stacking portion 141A, a current collector side joining portion 182 that sandwiches the insulating member 190 between the electrode body side joining portion 181 and a penetrating portion 183 that penetrates the insulating member. With. The electrode body side joint portion 181 is disposed on the electrode body 140 side (positive electrode laminate portion 141A side) of the insulating member 190. The positive electrode laminate portion 141 </ b> A is an exposed portion where the positive electrode 141 is exposed and is joined to the electrode body side joint portion 181. The current collector-side joint 182 is disposed on the positive electrode current collector 120 side of the insulating member 190 and is joined to the positive electrode current collector 120. The penetrating portion 183 connects the electrode body side joint portion 181 and the current collector side joint portion 182.

  In the power storage element according to the present embodiment, in the constituent element of power storage element 10 according to the first embodiment, insulating member 190 is a boundary between stacked portion 140C that is a stacked body portion of electrode body 140 and positive electrode stacked portion 141A. An insulating inclined portion 191 that is inclined toward the positive electrode current collector 120 with respect to the direction of the surface on which the insulating member 190 is formed is provided in a region facing the surface. More specifically, the insulating inclined portion 191 is a region formed by the Z-axis negative direction and the Y-axis negative direction from the end in the Z-axis negative direction of the member main body that extends to the XZ plane of the insulating member 190. A plate-like member extending to The electrode body 140 includes a stacked portion 140C in which the positive electrode 141, the separator 143, and the negative electrode 142 are stacked, and a positive electrode stacked portion 141A that is an exposed portion.

  When the positive electrode current collector 120, the positive electrode laminate portion 141 </ b> A, and the cover 145 </ b> A are resistance-welded via the joined body 180, the separator 143 is connected to the positive electrode current collector 120 and the welding electrode 402 in a structure without the insulating inclined portion 191. It is assumed that it penetrates into the bonding interface. If the separator 143 is bitten between the positive electrode current collector 120 and the welding electrode 402 during resistance welding, the welding apparatus attempts to flow a predetermined welding current with the resistance between the welding electrodes increased. Therefore, an excessive voltage is applied between the welding electrodes. At this time, if the inserted separator 143 is pulled out due to vibration or the like, an excessive voltage is applied in a state where the resistance between the welding electrodes is rapidly reduced, so that an abnormal current flows, and the positive electrode base material foil constituting the positive electrode 141 May melt.

  On the other hand, according to the above configuration, the insulating inclined portion 191 can prevent the separator 143 from being caught between the welding electrode 402 and the positive electrode current collector 120, so that the foil can be melted by the abnormal current. Can be avoided.

  Also in the second embodiment, the structure of the positive electrode current collector and the bonded body in the bonding region 170 is not limited to the shape described in FIG. The structure of the positive electrode current collector and the joined body in the present embodiment may be the structure shown in FIGS. 5B to 5E shown in the first embodiment, and the same effects are produced.

(Other)
The power storage element according to the present invention has been described based on the embodiments. However, the present invention is not limited to the embodiment. Unless it deviates from the meaning of this invention, the thing which gave various deformation | transformation which those skilled in the art can think to embodiment, or the form constructed | assembled combining the some component demonstrated above is also in the range of this invention. included.

  For example, in Embodiments 1 and 2, it is assumed that the covers 145A and 145B are formed on the positive electrode stacking portion 141A and the negative electrode stacking portion 142B, respectively, but the cover is not an essential constituent element. There may be a configuration without.

  In addition, the members constituting the joined body such as the electrode body side joined portion 181, the current collector side joined portion 182, and the penetrating portion 183 may have a columnar shape or a prismatic shape.

  Moreover, the resistance welding location on the positive electrode side and the resistance welding location on the negative electrode side are not limited to one point each. At least one of the resistance welding locations on the positive electrode side and the negative electrode side may take the form of multipoint bonding.

  The structure of the electrode body 140 may not be a winding type, and may be a structure in which flat plate-like positive electrodes and negative electrodes are alternately stacked with a separator interposed therebetween. Further, the electrode body 140 may have a structure in which a long belt-like positive electrode and a negative electrode are folded in a bellows shape with a separator interposed therebetween. In other words, any structure may be adopted as the structure of the electrode body 140 as long as it has a portion that can be joined to the current collector.

  Further, in the electric storage element 10, the joint by resistance welding is arranged on both the positive electrode side and the negative electrode side. However, the resistance according to the first and second embodiments is applied only to either the positive electrode side or the negative electrode side. Joining by welding may be formed.

  In addition, this invention can be implement | achieved as a manufacturing method of the said electrical storage element not only as an electrical storage element provided with the characteristic structure mentioned above.

  That is, the method for manufacturing a power storage device according to the present invention includes an electrode body formed by laminating a positive electrode, a negative electrode, and a separator, an electrode terminal, and a current collector that electrically connects the electrode terminal and the electrode body. A method for manufacturing an electricity storage device comprising: a connecting portion connecting a first bonding portion and a second bonding portion is passed through an insulating member; an electrode body, a first bonding portion, a connection portion, a second bonding portion; Join the current collector.

  Here, the first joint is, for example, the electrode body side joint 181 in Embodiment 1, the second joint is, for example, the current collector side joint 182 in Embodiment 1, and the connection is For example, the penetrating portion 183 in the first embodiment.

  As a result, the insulating member is disposed around the connection portion, whereby the energization path when the electrode body and the current collector are resistance-welded is limited to the connection portion, and highly efficient resistance welding by current concentration can be performed. Moreover, since the welding current value can be set small, it is possible to reduce the risk of spatter foreign matter. Moreover, the arrangement | positioning of an insulating member can avoid the case where a welding electrode touches area | regions other than a welding part and a sputter | spatter foreign material is generated.

  The present invention is a power storage element in which an electrode body and a current collector are joined by resistance welding, and can provide a high-quality power storage element. Therefore, the electricity storage device according to the present invention is useful as a battery mounted in an automobile or the like that requires a large current for a long time.

DESCRIPTION OF SYMBOLS 10 Power storage element 110 Cover body 110a, 110b, 121a, 131a Through-hole 111 Case main body 120, 121, 122, 123 Positive electrode current collector 130 Negative electrode current collector 140 Electrode body 140C Laminating portion 141 Positive electrode 141A Positive electrode laminating portion 142 Negative electrode 142B Negative electrode laminated portion 143 Separator 145A, 145B Cover 170 Joining region 180, 185 Joined body 190 Insulating member 181, 186 Electrode body side joined portion 182, 187 Current collector side joined portion 183, 188 Through portion 191 Insulating inclined portion 200 Positive electrode terminal 210, 310 Protruding part 300 Negative electrode terminal 401, 402 Welding electrode 530 Negative electrode current collector 541 Negative electrode core exposed part 545 Negative electrode current collector receiving part 580 Protrusion 590 Heat-welding resin tape 590A Opening

Claims (9)

A power storage device comprising an electrode body formed by laminating a positive electrode, a negative electrode, and a separator, an electrode terminal, and a current collector that electrically connects the electrode terminal and the electrode body,
The power storage element further includes:
A joined body disposed between the electrode body and the current collector and joined to the electrode body and the current collector;
An insulating member disposed between the electrode body and the current collector;
The joined body is
A power storage device comprising a penetrating portion that penetrates the insulating member. The power storage element according to claim 1, wherein the insulating member is disposed so as to cover a surface of the current collector facing the electrode body. The power storage device according to claim 1, wherein the penetrating portion is in contact with the insulating member. The joined body further includes:
An electrode body side joint disposed on the electrode body side of the insulating member and joined to the electrode body;
A collector-side joint disposed on the current collector side of the insulating member, joined to the current collector, and sandwiching the insulating member with the electrode body-side joint;
The power storage device according to any one of claims 1 to 3, wherein the penetrating portion connects the electrode body side joint and the current collector side joint. The joined body further includes:
An electrode body side joint disposed on the electrode body side of the insulating member and joined to the electrode body;
A current collector-side joint disposed on the current collector side of the insulating member and joined to the current collector;
The penetrating portion connects the electrode body side joint and the current collector side joint,
The electrode body has a laminated main body portion in which the positive electrode, the separator, and the negative electrode are laminated, and an exposed portion in which the positive electrode or the negative electrode is exposed from the laminated main body portion and joined to the electrode body side joint portion. And
The insulating member includes an insulating inclined portion that is inclined toward the current collector with respect to a forming surface direction of the insulating member in a region facing a boundary between the laminated main body portion and the exposed portion. The electrical storage element of any one of Claims. The electricity storage device according to claim 1, wherein the joined body and the insulating member are joined by caulking. The insulating member is integrally formed with the joined body by resin insert molding.
The electrical storage element of any one of Claims 1-5. The electricity storage device according to claim 1, wherein the joined body is integrally formed with the current collector. A method of manufacturing an electricity storage device comprising an electrode body formed by laminating a positive electrode, a negative electrode, and a separator, an electrode terminal, and a current collector that electrically connects the electrode terminal and the electrode body,
Passing through the insulating member through the connecting portion connecting the first joint and the second joint,
A method for manufacturing a storage element, wherein the electrode body, the first joint portion, the connection portion, the second joint portion, and the current collector are joined.

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