JP6105986B2 - Power storage device and method for manufacturing power storage device - Google Patents

Description

  The present invention relates to a power storage element and a method for manufacturing the power storage element.

  In a secondary battery such as a lithium ion secondary battery, a power generation element is accommodated in a battery can and an electrolyte is injected. The battery can is sealed with a battery lid. The electrolytic solution is injected into the battery can from a liquid injection part provided on the battery lid, and after the injection, the liquid injection part is sealed with a sealing plug. The sealing plug is inserted into the liquid injection part and is usually joined to the liquid injection part by laser welding or the like.

  In consideration of the insertion property of the sealing plug into the liquid injection part, a gap is required between the liquid injection part and the sealing plug. However, if this gap is too large, the weld metal for sealing the gap is insufficient, and a weld defect such as a crack may occur in the weld metal.

  Patent Document 1 discloses a battery in which a protrusion that is melted at the time of welding is provided on the outer surface of the sealing plug, and the sealing plug is used by utilizing a molten metal (molten pool) of the protrusion at the time of welding. A method of welding to a liquid injection part is disclosed.

JP 2012-18861 A

  In the method of welding the sealing plug to the liquid injection part by laser welding, electron beam welding, or the like, welding is performed along the outer periphery of the sealing plug with a predetermined position as a welding start point. For this reason, in the process in which welding is performed in the circumferential direction, the metal melted at the welding start point may cause solidification shrinkage, and the sealing plug may float accordingly.

The electricity storage device according to claim 1 is a container in which a power generation element is accommodated, a liquid injection part provided on one side of the container, having a liquid injection hole for injecting an electrolytic solution, and a seal for sealing the liquid injection hole. The liquid injection hole is provided on the bottom surface of the concave portion provided in one side of the container, and the sealing plug is fitted into the insertion portion to be inserted into the liquid injection hole and fitted into the concave portion. A plastic deformation portion having at least one of a peripheral portion of the fitting portion and an opening peripheral portion of the concave portion, and the outer peripheral side surface of the fitting portion and the inner peripheral side surface of the concave portion are in contact with each other at a predetermined position. The sealing plug is eccentrically arranged on the opposite side of the plastic deformation part with respect to the liquid injection part, and is located between the outer peripheral side surface of the fitting part and the concave part at a position facing the plastic deformation part across the liquid injection hole. and peripheral sides abut, wherein the weld along the entire periphery of the inner peripheral side of the outer peripheral side surface and the concave portion of the fitting portion is formed.
The method for manufacturing a power storage device according to claim 4 includes: a housing step of housing the power generation element in the container; and an electrolyte solution in the container from a liquid injection hole provided in a bottom surface of the recess formed in one side of the container. A storage element manufacturing method including a liquid injection process for injecting a liquid and a sealing process for sealing a liquid injection hole with a sealing plug, wherein the sealing process is performed by pouring an insertion portion provided in the sealing plug. The placement step of inserting the fitting portion provided in the sealing plug into the recess and inserting the fitting portion into the recess, and at least the first position in either the peripheral portion of the fitting portion or the opening peripheral portion of the recess The outer peripheral side surface of the fitting portion and the inner peripheral side surface of the concave portion at the first position are pressed to form a plastic deformation portion, and the sealing plug is pressed against the concave portion with the plastic deformation portion. And the outer peripheral side surface of the fitting portion at the second position facing the plastic deformation portion across the liquid injection hole. A temporary fixing step of temporarily fixing the contact portion by contacting the inner peripheral side surface of the portion, and a welding step of welding the outer peripheral side surface of the fitting portion and the inner peripheral side surface of the concave portion over the entire circumference. And

  According to the present invention, when the sealing plug is welded to the liquid injection part, the sealing plug is prevented from floating, and the sealing reliability can be improved.

1 is an external perspective view of a prismatic secondary battery as an embodiment of a power storage device according to the present invention. FIG. 2 is an exploded perspective view of the prismatic secondary battery shown in FIG. 1. The perspective view of the state which expand | deployed the electric power generation element shown by FIG. 2 the winding termination | terminus part side. The expansion disassembled perspective view of the sealing structure which shows a sealing stopper and a liquid injection part. (A) is a cross-sectional schematic diagram which shows the state by which the sealing stopper is arrange | positioned in the liquid injection part, (b) is a cross-sectional schematic diagram which shows the state in which the sealing plug was temporarily fixed to the liquid injection part. (A) is a cross-sectional schematic diagram which shows a mode that a sealing plug is laser-welded to a liquid injection part, (b) is a cross-sectional schematic diagram which shows the state after a sealing plug is welded to a liquid injection part. (A) is a plane schematic diagram which shows the state by which the sealing plug is arrange | positioned in the liquid injection part, (b) is a plane schematic diagram which shows the state by which the sealing plug was temporarily fixed to the liquid injection part. (A) And (b) is a plane schematic diagram which shows a mode that a sealing stopper is laser-welded to a liquid injection part. The plane schematic diagram which shows the state after the sealing stopper was welded to the liquid injection part. The cross-sectional schematic diagram explaining the sealing method of the liquid injection hole by the sealing plug in the electrical storage element which concerns on 2nd Embodiment. The plane schematic diagram explaining the sealing method of the liquid injection hole by the sealing plug in the electrical storage element which concerns on 3rd Embodiment. The cross-sectional schematic diagram explaining the sealing method of the injection hole by the sealing plug in the electrical storage element which concerns on the modification of 1st Embodiment. The cross-sectional schematic diagram explaining the sealing method of the injection hole by the sealing plug in the electrical storage element which concerns on the modification of 2nd Embodiment. The figure which shows the sealing stopper in which the several plastic deformation part was formed, and the liquid injection part in the electrical storage element which concerns on a modification.

Hereinafter, an embodiment of a power storage device and a method for manufacturing the power storage device of the present invention will be described with reference to the drawings.
-First embodiment-
FIG. 1 is an external perspective view of a prismatic secondary battery as an embodiment of a power storage device according to the present invention, and FIG. 2 is an exploded perspective view of the prismatic secondary battery shown in FIG. In the following description, the prismatic secondary battery is described as a lithium ion prismatic secondary battery. For convenience of explanation, the vertical direction is defined as shown.

  As shown in FIG. 1, the rectangular secondary battery 100 includes a rectangular battery container (container) 103 including a battery can 101 and a battery lid 102. The material of the battery can 101 and the battery lid 102 is, for example, an aluminum-based metal such as aluminum or an aluminum alloy.

  The battery lid 102 has a rectangular flat plate shape and is joined so as to close the opening 101 d (see FIG. 2) of the battery can 101. That is, the battery lid 102 seals the battery can 101. The battery lid 102 is provided with a positive terminal 141 and a negative terminal 151. The battery cover 102 is provided with a gas discharge valve 104. The gas discharge valve 104 is formed, for example, by partially thinning the battery lid 102 by press working. The gas discharge valve 104 is formed with a cleavage groove so that a large opening is formed at the time of cleavage. The gas discharge valve 104 is heated when the rectangular secondary battery 100 generates heat due to an abnormality such as overcharge, and gas is generated therein. When the pressure in the battery container 103 rises and reaches a predetermined pressure, the gas discharge valve 104 is opened. The pressure in the battery container 103 is reduced by discharging the gas from the battery.

The battery lid 102 is formed with a liquid injection part 110 (see FIG. 4) having a liquid injection hole 111 for injecting an electrolytic solution into the battery container 103. As the electrolytic solution, for example, a non-aqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a carbonate-based organic solvent such as ethylene carbonate can be used.

  The liquid injection hole 111 is a through hole that communicates the inside and outside of the battery container 103, and is sealed by the sealing plug 120 after the electrolyte is injected. Details of the sealing structure of the liquid injection hole 111 by the sealing plug 120 and the sealing method will be described later.

  As shown in FIG. 2, the power generation element 170 is accommodated in the battery can 101. The battery can 101 has a pair of wide surfaces 101a, a pair of narrow surfaces 101b, and a bottom surface 101c, and is formed in a rectangular box shape with an upper surface opened. The power generation element 170 is accommodated in the battery can 101 while being covered with the insulating case 108. The material of the insulating case 108 is an insulating resin such as polypropylene. Thereby, the battery can 101 and the power generation element 170 are electrically insulated.

  The positive electrode terminal 141 is electrically connected to the positive electrode 174 of the power generation element 170 via the positive electrode current collector 181, and the negative electrode terminal 151 is electrically connected to the negative electrode 175 of the power generation element 170 via the negative electrode current collector 182. Has been. Thereby, electric power is supplied to the external load via the positive electrode terminal 141 and the negative electrode terminal 151, or external generated electric power is supplied to the power generation element 170 via the positive electrode terminal 141 and the negative electrode terminal 151 to be charged.

  The battery lid assembly 107 includes a battery lid 102, a positive electrode terminal 141 and a negative electrode terminal 151 attached to each of a pair of through holes 102 h provided in the battery lid 102, and a positive electrode current collector 181 and a negative electrode current collector 182. And a pair of gaskets 150 and a pair of insulating members 160.

  The material of the positive electrode terminal 141 and the positive electrode current collector 181 is aluminum or an aluminum alloy. The material of the negative electrode terminal 151 and the negative electrode current collector 182 is copper or a copper alloy. The material of the insulating member 160 and the gasket 150 is an insulating resin such as polybutylene terephthalate, polyphenylene sulfide, or perfluoroalkoxy fluororesin.

The power generating element 170 will be described with reference to FIG. FIG. 3 is a perspective view of the power generation element 170 shown in FIG. 2 in a state where the winding terminal end side is developed.
As shown in FIG. 3, the power generation element 170 that is also a power storage element is obtained by winding a long positive electrode 174 and a negative electrode 175 in a flat shape around a winding axis U with a separator 173 interposed therebetween. It is a laminated structure. That is, the power generation element 170 is a flat wound electrode group in which a circular arc part having a semicircular cross section is formed at both ends, and a flat part between both the end parts is a flat part.

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

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

  One end of both ends of the power generation element 170 in the width direction (winding axis U direction orthogonal to the winding direction) is an uncoated portion where the positive electrode active material mixture layer 176 is not formed (exposed portion of the positive electrode foil 171). Are the stacked portions. The other is a portion where an uncoated portion (exposed portion of the negative electrode foil 172) where the negative electrode active material mixture layer 177 is not formed is laminated. The laminated body of the positive electrode side uncoated part and the laminated body of the negative electrode side uncoated part are respectively crushed in advance, respectively, and the positive electrode current collector 181 and the negative electrode current collector 182 of the battery lid assembly 107 (see FIG. 2). ) By ultrasonic bonding and integrated with the battery lid assembly 107.

  The shapes of the sealing plug 120 and the liquid injection part 110 will be described. FIG. 4 is an enlarged exploded perspective view of the sealing structure showing the sealing plug 120 and the liquid injection part 110.

  The liquid injection part 110 includes a circular recess 112 formed in the outer surface of the battery lid 102, and a circular liquid injection hole 111 formed through the bottom surface 112 b of the recess 112 in the thickness direction of the battery cover 102. Have The recess 112 and the liquid injection hole 111 are formed concentrically. In other words, the liquid injection part 110 is a stepped hole having a recess 112 that constitutes a large-diameter opening and a liquid injection hole 111 that constitutes a small-diameter opening. The recess 112 is provided so as to be recessed toward the inside of the battery container 103 on the upper surface (outside of the battery container 103) side of the battery lid 102 constituting one side surface of the battery container 103. The recess 112 is formed, for example, by spot facing. The recess 112 has a bottom surface 112b and a side surface (hereinafter referred to as an inner peripheral side surface 112i) rising from the outer peripheral end of the bottom surface 112b. The bottom surface 112b of the recess 112 is a surface with which the lower surface of the flange (fitting portion) 122 of the sealing plug 120 is brought into contact.

  The sealing plug 120 is made of, for example, an aluminum-based metal such as aluminum or an aluminum alloy. The sealing plug 120 includes a cylindrical tube portion 121 having a bottom portion 121 a and an annular flange portion 122 formed on the upper outer periphery of the tube portion 121. The flange portion 122 and the cylindrical portion 121 are formed concentrically. In other words, the sealing plug 120 has a stepped shape having the flange portion 122 constituting the large diameter portion and the cylindrical portion 121 constituting the small diameter portion. The peripheral edge of the flange 122 is a protrusion 122 a that protrudes upward (outside the battery container 103) from the outer surface of the battery lid 102 when the sealing plug 120 is disposed in the liquid injection part 110. (Refer FIG. 5) and the protrusion part 122a are provided over the perimeter of the collar part 122. FIG. A hollow portion 125 having an opening on the flange 122 side is formed at the center of the cylindrical portion 121 and the flange 122 of the sealing plug 120, and the sealing plug 120 has a substantially hat-shaped shape.

  A method for manufacturing prismatic secondary battery 100 according to the first embodiment will be described. The manufacturing method of the prismatic secondary battery 100 includes an accommodating step of accommodating the power generation element 170 in the battery container, an injecting step of injecting an electrolytic solution into the battery container from the injecting hole 111, and an injection by the sealing plug 120. And a sealing step for sealing the hole 111.

-Containment process-
The power generation element 170 integrated with the battery lid assembly 107 is accommodated in the insulating case 108 accommodated in the battery can 101. At this time, the power generating element 170 is placed in the battery can 101 so that the winding axis U is parallel to the bottom surface 101 c of the battery can 101 and the pair of flat portions are parallel to the wide surface 101 a of the battery can 101. To house. The opening 101d of the battery can 101 is closed by the battery lid 102 of the battery lid assembly 107, and the periphery of the battery lid 102 is joined to the opening periphery of the battery can 101 by laser welding or the like.

-Injection process-
The battery container 103 is placed on a flat table (not shown) so that the battery lid 102 is on the upper side, and an injection jig (not shown) having two functions of decompression and electrolyte injection inside the battery container is added. Attach to the liquid hole 111. The pressure is reduced until the internal pressure of the battery container 103 becomes about 27 kPa, for example, and then a predetermined amount of electrolyte is injected.

-Sealing process-
The sealing process for sealing the liquid injection hole 111 with the sealing plug 120 includes an arrangement process for arranging the sealing plug 120 in the liquid injection part 110 and a temporary fixing process for temporarily fixing the sealing plug 120 to the liquid injection part 110. And a welding step of welding the sealing plug 120 to the liquid injection part 110 and sealing the liquid injection hole 111.

  With reference to FIGS. 5-9, the sealing method which seals the liquid injection hole 111 with the sealing stopper 120, and the detail of a sealing structure are demonstrated. 5 and 6 are cross-sectional schematic views showing the sealing structure of the liquid injection hole 111, showing a cross section taken along the line VV of FIG. 7 to 9 are schematic plan views of the battery lid 102 as viewed from above. FIGS. 5A and 7A show a state where the sealing plug 120 is disposed in the liquid injection part 110, and FIGS. 5B and 7B show the state where the sealing plug 120 is the liquid injection part 110. FIG. The state temporarily stopped is shown. FIGS. 6A, 8 </ b> A, and 8 </ b> B show how the sealing plug 120 is welded to the liquid injection part 110. FIG. 6B and FIG. 9 show a state after the sealing plug 120 is welded to the liquid injection part 110. For convenience, as shown in the figure, the vertical direction is the Z direction, the winding axis U direction is the Y direction, and the direction orthogonal to each of the Z direction and the Y direction is the X direction.

-Placement process-
In the arrangement step of arranging the sealing plug 120 in the liquid injection part 110, as shown in FIG. 5A and FIG. 7A, the cylinder part (insertion part) 121 of the sealing plug 120 is provided in the liquid injection hole 111. Insert and fit the flange (fitting portion) 122 into the recess 112. As shown in FIG. 5A, the outer diameter do1 of the flange 122 that constitutes the large-diameter portion of the sealing plug 120 is slightly smaller than the inner diameter Di1 of the recess 112 that constitutes the large-diameter opening of the liquid injection portion 110. (Do1 <Di1). The outer diameter do2 of the cylindrical part 121 constituting the small diameter part of the sealing plug 120 is slightly shorter than the inner diameter Di2 of the liquid injection hole 111 constituting the small diameter opening part of the liquid injection part 110 (do2 <Di2). For this reason, in the state where the sealing plug 120 is disposed in the liquid injection part 110, there is a gap between the outer peripheral side surface 122 o of the collar part (large diameter part) 122 and the inner peripheral side surface 112 i of the concave part (large diameter opening part) 112. c <b> 1 is formed, and a gap c <b> 2 is formed between the outer peripheral side surface 121 o of the cylindrical portion (small diameter portion) 121 and the inner peripheral side surface 111 i of the liquid injection hole (small diameter opening portion) 111. The length of the gap c2 is set to be the same as or slightly longer than the length of the gap c1 (Di1-do1 ≦ Di2-do2).

-Temporary fixing process-
In the temporary fixing step of temporarily fixing the sealing plug 120 to the liquid injection part 110, as shown in FIGS. 5 (a) and 5 (b), a predetermined position of the protruding part 122a constituting the peripheral part of the flange part 122 ( Hereinafter, the first position 1 </ b> A) is pressed from above (outside the battery container 103) by the pressing jig 190 to form the plastic deformation portion 127.

  The pressing jig 190 has a cube-shaped pressing portion 191, and the lower surface of the pressing portion 191 is a flat surface. When the lower surface of the pressing portion 191 is brought into contact with the upper surface of the protruding portion 122a and pressed downward, as shown in FIGS. 5B and 7B, the protruding portion 122a is vertically moved at the first position 1A. The plastic deformation portion 127 is formed by being compressed in the (Z direction) and deforming so as to project outward in the radial direction (+ X direction). When the protrusion 122a is deformed and protrudes in the + X direction, the outer peripheral side surface of the plastic deformation portion 127 comes into contact with the inner peripheral side surface 112i of the recess 112, and the outer peripheral side surface of the plastic deformation portion 127 comes from the inner peripheral side surface 112i of the recess 112. Reaction force acts. A gap c1 is formed between the flange 122 and the recess 112 of the sealing plug 120, and a gap c2 is formed between the cylinder 121 and the liquid injection hole 111. When the reaction force from 112i acts on the outer peripheral side surface of the plastic deformation portion 127, the sealing plug 120 moves in the -X direction.

  As shown in FIG. 7B, when the sealing plug 120 moves by a predetermined distance in the −X direction, the position facing the plastic deformation portion 127 across the liquid injection hole 111 (hereinafter referred to as the second position 1B). ), The outer peripheral side surface 122o of the sealing plug 120 and the inner peripheral side surface 112i of the recess 112 abut. That is, the outer peripheral side surface 122o of the flange 122 and the inner peripheral side surface 112i of the concave portion 112 are in line contact with each other at the second position 1B.

  When the pressing operation by the pressing jig 190 is completed, the outer peripheral side surface of the plastic deformation portion 127 is brought into close contact with the inner peripheral side surface 112 i of the recess 112. That is, the outer peripheral side surface of the plastic deformation portion 127 constituting the outer peripheral side surface 122o of the flange 122 at the first position 1A is in surface contact with the inner peripheral side surface 112i of the recess 112.

  Thus, the outer peripheral side surface 122o of the flange 122 of the sealing plug 120 and the inner peripheral side surface 112i of the recess 112 of the liquid injection unit 110 are in surface contact at the first position 1A, and the line at the second position 1B. The sealing plug 120 is temporarily fixed in a state where the sealing plug 120 is eccentrically arranged on the opposite side (−X direction) of the plastic deformation portion 127 with respect to the liquid injection portion 110. In other words, as shown in FIG. 7B, the sealing plug 120 has the central axis O1 of the sealing plug 120 positioned on the line contact portion CP side with respect to the central axis O2 of the liquid injection hole 111, and The first position 1A and the second position 1B are fixed while being sandwiched by the liquid injection unit 110.

-Welding process-
In the welding process of welding the sealing plug 120 to the battery lid 102, for example, using a YAG pulse laser welding machine (not shown), the energy of one pulse is 6 J, the pulse frequency is 60 pulses / sec, the average output is 360 W, and the welding speed is Laser light 196 is irradiated at 10 mm / sec. As shown in FIGS. 6A and 8A, the laser welding start point (hereinafter referred to as welding start point SP) is set at the second position 1B, and the collar portion at the second position 1B. Laser light 196 is irradiated in a direction perpendicular to the outer surface of the battery cover 102 (−Z direction) toward the boundary between the outer peripheral side surface 122o of 122 and the inner peripheral side surface 112i of the recess 112. That is, in the first embodiment, the welding start point SP and the line contact portion CP coincide with each other.

  As shown in FIG. 8B, the outer peripheral side surface 122o of the flange 122 and the inner peripheral side surface 112i of the recess 112 are welded over the entire circumference along the outer peripheral side surface 122o of the flange 122 from the welding start point SP. . When the laser light irradiation region 197 is moved from the welding start point SP along the outer peripheral side surface 122o of the flange 122, the molten pool gradually solidifies in the portion where the welding operation is completed during the movement. In this embodiment, since the sealing plug 120 is temporarily fixed to the liquid injection part 110, the sealing plug 120 is floated by expansion when the molten pool is generated and contraction when the molten pool solidifies. As shown in FIG. 9, good weld metal W can be formed over the entire circumference of the sealing plug 120.

According to the first embodiment described above, the following operational effects are obtained.
(1) The first position 1A of the peripheral portion of the flange 122 is pressed from the outside of the battery container 103 to form the plastic deformation portion 127, and the sealing plug 120 is plastically deformed with respect to the liquid injection portion 110. The outer peripheral side surface 122o of the flange portion 122 and the inner peripheral side surface 112i of the concave portion 112 were welded over the entire periphery. Accordingly, when the sealing plug 120 is welded to the liquid injection part 110, the sealing plug 120 is prevented from floating from the battery lid 102, and the sealing reliability of the sealing plug 120 with respect to the liquid injection part 110 is improved. can do.

  On the other hand, for example, when laser welding is performed in a state where the sealing plug 120 shown in FIG. 5A is loosely fitted in the liquid injection part 110, the molten pool is generated at the welding start point. The sealing plug 120 may be lifted from the battery lid 102 due to expansion or contraction when the molten pool solidifies. In this case, a sufficient molten pool cannot be generated between the sealing plug 120 and the battery lid 102 at the floating portion, and there is a possibility that a weld defect such as a crack may occur in the weld metal. In the present embodiment, by forming the plastic deformation portion 127, the sealing plug 120 is fixed to the liquid injection section 110, and the sealing plug 120 is prevented from floating during welding. A sufficient molten pool is generated between the plug 120 and the battery lid 102, and welding defects are prevented from occurring in the weld metal W.

(2) The peripheral edge of the flange 122 is a protrusion 122 a that protrudes from the outer surface of the battery lid 102 toward the outside of the battery container 103. For this reason, it is prevented that the molten metal (molten pool) which should be filled in the clearance c1 between the outer peripheral side surface 122o of the flange 122 and the inner peripheral side surface 112i of the recess 112 is insufficient. In other words, by providing the protrusion 122a, the gap c1 can be set larger than in the case where the protrusion 122a is not provided, and the productivity can be improved.

-Second Embodiment-
With reference to FIG. 10, a method for sealing a liquid injection hole with a sealing plug in the energy storage device according to the second embodiment will be described. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and differences will be mainly described. 10 (a) and 10 (b) are the same views as FIGS. 5 (a) and 6 (a), and a liquid injection hole by the sealing plug 220 in the electricity storage device according to the second embodiment. It is a cross-sectional schematic diagram explaining the sealing method of 111. FIG.

  In the first embodiment, the protrusion 122a is provided on the collar 122, and the protrusion 122a at the first position 1A is pressed to form the plastic deformation portion 127 (see FIG. 5). On the other hand, in 2nd Embodiment, the projection part is not provided in the collar part 222 of the sealing plug 220. FIG. In the second embodiment, the opening peripheral edge of the recess 212 in the battery lid 102 is formed as a protrusion 212a protruding from the battery lid 102 in the + Z direction (outward of the battery container 103) on the entire periphery of the recess 212. It is provided over. The inner peripheral side surface of the annular protrusion 212 a constitutes a part of the inner peripheral side surface 212 i of the recess 212.

  In the second embodiment, the plastic deformation portion 227 is formed by pressing the projection 212a constituting the opening peripheral edge of the recess 212 of the battery lid 102 at the first position 1A with the pressing jig 190. When the protrusion 212a is pressed by the pressing jig 190, the protrusion 212a is compressed in the Z direction and deformed mainly inward in the radial direction while suppressing the amount of deformation of the liquid injection part 110 in the radially outward direction. The inner side surface of the plastic deformation portion 227 presses the outer peripheral side surface 222o of the flange 222 of the sealing plug 220, and the sealing plug 220 moves in the −X direction. When the sealing plug 220 moves by a predetermined distance, the outer peripheral side surface 222o of the flange 222 is abutted against the inner peripheral side surface 212i of the recess 212 at the second position 1B.

  Thereby, the plastic deformation portion 227 is in surface contact with the outer peripheral side surface 222o of the flange portion 222 of the sealing plug 220 at the first position 1A, and the outer peripheral side surface 222o of the flange portion 222 is in the recess 212 at the second position 1B. The sealing plug 220 is temporarily fixed in a state of being in line contact with the inner peripheral side surface 212i.

  According to such 2nd Embodiment, there exists an effect similar to 1st Embodiment.

-Third embodiment-
With reference to FIG. 11, a method for sealing a liquid injection hole with a sealing plug in the energy storage device according to the third embodiment will be described. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and differences will be mainly described. FIG. 11 is a view similar to FIG. 8 and is a schematic plan view illustrating a method for sealing the liquid injection hole 111 with the sealing plug 120 in the energy storage device according to the third embodiment.

  In the first embodiment, the welding start point SP is set at the line contact portion CP at the second position 1B (see FIG. 8A). On the other hand, in the third embodiment, as shown in FIG. 11A, the welding start point SP is set at a position away from the line contact portion CP at the second position 1B by a predetermined distance in the circumferential direction. ing. The position of the welding start point SP may be any position on the outer periphery of the sealing plug 120, and the welding direction may be either clockwise or counterclockwise in plan view. However, the position of the welding start point SP is preferably a position where the dimension of the gap c1 is as small as possible. By setting the welding start point SP at a position where the dimension of the gap c1 is small, it is effective that the sealing plug 120 is pulled toward the welding start point SP when the molten pool is solidified and contracted, and the position is shifted. This is because it can be prevented. Therefore, in order to suppress the floating of the sealing plug 120 more effectively, it is preferable to determine the position of the welding start point SP and the welding direction as follows.

  As shown in FIG. 11, a virtual plane including a line segment L connecting the plastic deformation portion 127 and the central axis O2 of the liquid injection hole 111 is defined as a first plane S1, orthogonal to the first plane S1, and the liquid injection hole A virtual plane including 111 central axis O2 is defined as second plane S2.

  The welding start point SP is set to the first region A1 that does not have the plastic deformation portion 127 in the regions A1 and A2 divided into two by the second plane S2. In other words, the welding start point SP is farther from the welding start point SP and the line contact portion CP at the second position 1B than the separation distance between the welding start point SP and the plastic deformation portion 127 at the first position 1A. The position is set so that the distance becomes shorter.

  In the welding process in the third embodiment, as shown in FIG. 11 (a), from the welding start point SP set in the first region A1 toward the second position 1B, that is, in the illustrated R1 direction, The outer peripheral side surface 122o of the flange 122 and the inner peripheral side surface 112i of the recess 112 are welded along the outer peripheral side surface 122o of the portion 122. In the welding process in the third embodiment, as shown in FIG. 11 (b), after the outer peripheral side surface 122o of the flange 122 and the inner peripheral side surface 112i of the recess 112 are welded at the second position 1B, the first The outer peripheral side surface 122o of the flange 122 and the inner peripheral side surface 112i of the recess 112 are welded at the position 1A.

  According to such 3rd Embodiment, there exists an effect similar to 1st Embodiment. Further, according to the third embodiment, when the weld pool is generated, compared to the case where the welding start point SP is set in the second region A2 or when welding is performed in the R2 direction from the welding start point SP. The amount of movement of the sealing plug 120 due to the expansion of the melt and the shrinkage when the molten pool solidifies can be suppressed.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(1) In 1st Embodiment, the 1st position 1A of the peripheral part of the collar part 122 is pressed, and the plastic deformation part 127 is formed, and in 2nd Embodiment, the opening peripheral part of the recessed part 212 is formed. Although the first position 1A is pressed to form the plastic deformation portion 227, the present invention is not limited to this. Both the peripheral edge portions of the flange portions 122 and 222 and the opening peripheral edge portion of the concave portions 112 and 212 are simultaneously pressed by the pressing jig 190, and the plastic deformation portions 127 and 212 are respectively applied to the flange portions 122 and 222 and the concave portions 112 and 212. 227 may be formed.

(2) In the first embodiment, the peripheral edge of the flange 122 is a protrusion 122a protruding from the battery lid 102 toward the outside of the battery container 103. In the second embodiment, the recess 212 The peripheral edge of the opening was a protrusion 212 a protruding from the battery lid 102 toward the outside of the battery container 103. The widths and heights of the protrusions 122a and 212a are such that a sufficient molten pool is generated so that the gap c1 is filled with the weld metal even when the dimensional tolerance of the gap c1 is maximized. Is set. However, the protrusions 122a and 212a may be omitted if a sufficient molten pool can be generated without providing the protrusions 122a and 212a. As shown in FIG. 12, in the first embodiment, even when the protrusion 122 a is omitted, by forming the plastic deformation portion 327 at the first position 1 </ b> A of the peripheral portion of the flange portion 122, the sealing plug 120 can be fixed to the liquid injection part 110, and the sealing plug 120 can be prevented from floating during welding. Similarly, as shown in FIG. 13, in the second embodiment, even when the protrusion 212a is omitted, by forming the plastic deformation portion 427 at the first position 1A of the opening peripheral portion of the recess 212, The sealing plug 220 can be fixed to the liquid injection part 110, and the sealing plug 220 can be prevented from floating during welding.

(3) The width and depth of the weld metal W formed over the entire circumference of the sealing plugs 120 and 220 are not limited to the above-described embodiment. In FIG. 9, the width (radial direction) of the annular weld metal W in a plan view is larger than the X-direction length (the radial direction length) of the plastic deformation portion 127 and the width (the radial direction length) of the protrusion 122 a. The weld metal W is formed so that the length of the plastic deformation portion 127 is shortened. For example, the length of the plastic deformation portion 127 in the X direction (the length in the radial direction) and the width of the projection portion 122a (the length in the radial direction). ), The weld metal W may be formed so that the width (the length in the radial direction) of the weld metal W is longer.

(4) Although the lithium ion secondary battery has been described as an example of the storage element, the present invention is not limited to this. The present invention can be applied to various secondary storage devices such as nickel-metal hydride batteries, lithium ion capacitors and electrolytic double layer capacitors. Further, the shape of the container is not limited to a square shape.

(5) The welding conditions are not limited to the above example. Further, instead of laser welding, the sealing plugs 120 and 220 may be welded to the battery lid 102 by electron beam welding.
(6) Furthermore, the 1st position 1A which forms a plastic deformation part is not limited to an above-described example.

(7) In the above-described embodiment, the case where one plastic deformation portion 127, 227, 327, 427 is provided has been described, but the present invention is not limited to this. Two or more plastic deformation portions may be provided. For example, as shown in FIG. 14A, three plastic deformation portions 527 may be provided, or as shown in FIG. 14B, four plastic deformation portions 627 may be provided. When a plurality of plastic deformation portions 527 and 627 are provided, as shown in FIG. 14, only one region E2 of the regions E1 and E2 divided by a predetermined virtual plane S5 including the central axis O2 of the liquid injection hole is provided. The plastic deformation portions 527 and 627 are provided, and the plastic deformation portions 527 and 627 are not provided in the other region E1. Thereby, the sealing plug 120 can be decentered to the region E1 side, and the sealing plug 120 can be temporarily fixed.

  When two or more plastic deformation portions 527 and 627 are provided, the first plane S1 and the second plane S2 are defined as follows. An arbitrary position between the plastic deformation portions at both ends in the circumferential direction in the region E2 is defined as a reference position BP, and a virtual plane including a line segment L connecting the reference position BP and the central axis O2 of the liquid injection hole is defined as a first plane S1. For example, as shown in FIG. 14A, the reference position BP can be set at a central plastic deformation portion 527 provided between the plastic deformation portions 527 at both ends in the circumferential direction. Further, as shown in FIG. 14B, the reference position BP can be set to a substantially central position between the plastic deformation portions 627 at both ends in the circumferential direction as the reference position BP. The second plane S2 is a virtual plane that is orthogonal to the first plane S1 and includes the central axis O2 of the liquid injection hole. When the first plane S1 and the second plane S2 are defined as described above, the welding start point SP is set in the area F1 that does not have the reference position BP among the areas F1 and F2 divided into two by the second plane S2. It is preferable. In FIGS. 14A and 14B, the second plane S2 and the virtual plane S5 are the same plane, and the areas E1 and E2 divided by the virtual plane S5 and the second plane S2 are divided into two. In the above description, the regions F1 and F2 are the same region, but the virtual plane S5 and the second plane S2 are not limited to the same plane.

  Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

1A 1st position, 1B 2nd position, 100 square secondary battery, 101 battery can, 101a wide surface, 101b narrow surface, 101c bottom surface, 102 battery lid, 102h through-hole, 103 battery container, 104 gas exhaust valve 107 Battery cover assembly, 108 Insulating case, 110 Injecting part, 111 Injecting hole, 111i Inner peripheral side, 112 Recessed part, 112b Bottom, 112i Inner peripheral side, 120 Sealing plug, 121 Tube part, 121a Bottom part, 121o Peripheral side surface, 122 collar portion, 122a protrusion, 122o Peripheral side surface, 125 hollow portion, 127 plastic deformation portion, 141 positive electrode terminal, 150 gasket, 151 negative electrode terminal, 160 insulating member, 170 power generation element, 171 positive electrode foil, 172 negative electrode foil , 173 separator, 174 positive electrode, 175 negative electrode, 176 positive electrode active material mixture layer, 177 negative electrode active material Mixture layer, 181 positive electrode current collector, 182 negative electrode current collector, 190 pressing jig, 191 pressing portion, 196 laser beam, 197 irradiation region, 212 concave portion, 212a protruding portion, 212i inner peripheral side surface, 220 sealing plug, 222 collar part, 222o outer peripheral side surface, 227 plastic deformation part, 327 plastic deformation part, 427 plastic deformation part, 527 plastic deformation part, 627 plastic deformation part

Claims (8)

A container containing a power generation element;
A liquid injection part provided on one side of the container and having a liquid injection hole for injecting an electrolyte;
A sealing stopper for sealing the liquid injection hole,
The liquid injection hole is provided on the bottom surface of a concave portion provided in one side of the container,
The sealing plug has an insertion portion to be inserted into the liquid injection hole and a fitting portion to be fitted into the concave portion,
At least a predetermined position of one of the peripheral edge of the fitting portion and the opening peripheral edge of the concave portion is formed with a plastic deformation portion where the outer peripheral side surface of the fitting portion and the inner peripheral side surface of the concave portion are in contact with each other. ,
The sealing stopper is arranged eccentrically on the opposite side of the plastic deformation part with respect to the liquid injection part,
The inner peripheral side of the outer peripheral side surface and the recess of the fitting portion at a position opposed to the plastic deformation portion across the injection hole is abutting the inner circumferential surface of the recess and the outer peripheral side surface of the fitting portion And a welding part is formed over the entire circumference. The electricity storage device according to claim 1,
A virtual plane including a line segment connecting the plastic deformation portion and the central axis of the liquid injection hole is a first plane,
When the virtual plane that is orthogonal to the first plane and includes the central axis of the liquid injection hole is the second plane,
The welding start point between the outer peripheral side surface of the fitting portion and the inner peripheral side surface of the recess is provided in a region that does not have the plastic deformation portion in a region divided into two by the second plane. A power storage element. The electricity storage device according to claim 1 or 2,
At least one of the peripheral edge portion of the fitting portion and the open peripheral edge portion of the concave portion protrudes from one side surface of the container toward the outside of the container. A housing step of housing the power generation element in the container, a liquid injection step of injecting an electrolyte into the container from a liquid injection hole provided in a bottom surface of a concave portion provided in one side of the container, and a sealing plug And a sealing step for sealing the liquid injection hole according to the method,
The sealing step includes
An insertion step of inserting an insertion portion provided in the sealing plug into the liquid injection hole, and fitting a fitting portion provided in the sealing plug into the recess; and
At least a first position in any one of the peripheral edge of the fitting portion and the opening peripheral edge of the recess is pressed from the outside of the container, and the outer peripheral side surface of the fitting portion in the first position and the A plastic deformation portion is formed in contact with the inner peripheral side surface of the recess, and the sealing plug is eccentric to the opposite side of the plastic deformation portion with respect to the recess, and the plastic is sandwiched between the liquid injection holes. A temporary fixing step of temporarily fixing the outer peripheral side surface of the fitting portion and the inner peripheral side surface of the concave portion at a second position facing the deforming portion by abutting;
The manufacturing method of the electrical storage element characterized by including the welding process of welding the outer peripheral side surface of the said fitting part, and the inner peripheral side surface of the said recessed part over a perimeter. In the manufacturing method of the electrical storage element of Claim 4,
The temporary fixing step includes pressing the first position in at least one of the peripheral edge portion of the fitting portion and the opening peripheral edge portion of the concave portion from the outside of the container, and the fitting in the first position. The outer peripheral side surface of the fitting portion forms a plastic deformation portion where the outer peripheral side surface of the concave portion and the inner peripheral side surface of the concave portion are in surface contact with each other, and the outer periphery of the fitting portion at a second position facing the plastic deformation portion with the liquid injection hole interposed therebetween A method of manufacturing a power storage element, wherein the side surface and the inner peripheral side surface of the recess are brought into line contact. In the manufacturing method of the electrical storage element according to claim 5,
A virtual plane including a line segment connecting the plastic deformation portion and the central axis of the liquid injection hole is a first plane,
When the virtual plane that is orthogonal to the first plane and includes the central axis of the liquid injection hole is the second plane,
The welding step sets a welding start point in a region that does not have the plastic deformation portion in a region divided into two by the second plane, and extends from the welding start point along the outer peripheral side surface of the fitting portion, A method for manufacturing a power storage element, comprising welding an outer peripheral side surface of a fitting portion and an inner peripheral side surface of the recess. In the manufacturing method of the electrical storage element of Claim 6,
In the welding step, after welding the outer peripheral side surface of the fitting portion and the inner peripheral side surface of the concave portion at the second position, the outer peripheral side surface of the fitting portion and the inner periphery of the concave portion at the first position A method for manufacturing a power storage element, comprising welding a side surface. In the manufacturing method of the electrical storage element of Claim 4 or 5,
At least one of the peripheral edge part of the fitting part and the opening peripheral edge part of the recess is a protrusion protruding from one side surface of the container toward the outside of the container,
In the temporary fixing step, the method of manufacturing a power storage element is characterized in that the projecting portion at the first position is pressed to form a plastically deformed portion.

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