JP2021192347A - Manufacturing method of power storage element and power storage element - Google Patents

Abstract

To provide a power storage element capable of improving the quality of welding between an electrode body and a current collector.SOLUTION: A manufacturing method of a power storage element 10 including an electrode body 300 having a laminated portion 320 in which electrode plates 301 are laminated in the stacking direction, and a current collector 400 bonded to the laminated portion 320 includes a temporary attachment step of temporarily attaching the electrode plates 301 laminated in the laminated portion 320 using heat to form a temporary attachment portion 710 in which the electrode plates 301 are temporarily attached to each other, and a laser welding step of irradiating a portion in which the temporary attachment portion 710 and the current collector 400 overlap with a laser beam L to laser-weld the temporary attachment portion 710 and the current collector 400.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method for manufacturing a power storage element including an electrode body on which electrode plates are laminated and a current collector bonded to the electrode body, and a power storage element.

Conventionally, a method for manufacturing a power storage element including an electrode body having a laminated portion in which electrode plates are laminated and a current collector bonded to the laminated portion is widely known. For example, in Patent Document 1, an electrode tap (stacked portion of an electrode body) formed so as to project from an electrode plate (electrode plate) and a lead portion (current collector) for electrically connecting the electrode tap to an external terminal are provided. An electrode tap welding method (method for manufacturing a power storage element) including a main welding step of connecting by resistance welding is disclosed.

Special Table 2016-531405 Gazette

In the conventional method for manufacturing a power storage element, the laminated portion of the electrode body and the current collector are joined by resistance welding. On the other hand, in laser welding, in general, it is possible to weld deeply in a short time, and stable welding is possible with little influence of heat. It may be preferable to join the current collector by laser welding in order to improve the quality of welding. However, when the laminated portion and the current collector are joined by laser welding, if there is an air layer between the plates at the welded part, spatter or blow holes may occur and the welding quality may deteriorate. be.

The present invention has been made by the inventor of the present application paying new attention to the above-mentioned problems, and is a method for manufacturing a power storage element capable of improving the quality of welding between an electrode body and a current collector, and power storage. The purpose is to provide an element.

In order to achieve the above object, the method for manufacturing a power storage element according to one aspect of the present invention includes an electrode body having a laminated portion in which electrode plates are laminated in the stacking direction, and a current collector bonded to the laminated portion. A method for manufacturing a power storage element, comprising: The present invention includes a laser welding step of irradiating a portion where the temporary attachment portion and the current collector are overlapped with a laser beam and laser welding the temporary attachment portion and the current collector.

According to this, the method of manufacturing the power storage element includes a temporary attachment step of temporarily attaching the laminated electrode plates to each other in the laminated portion of the electrode body by using heat to form a temporary attachment portion, and a temporary attachment portion and a current collector. Includes a laser welding process for laser welding and. In this way, by temporarily attaching the plates of the laminated portion to each other using heat to form the temporary attachment portion, air is provided between the plates without using a complicated device or jig for holding the plates. The formation of layers can be easily suppressed. Further, by laser welding the temporary attachment portion and the current collector, laser welding can be performed at a place where the formation of an air layer between the plates is suppressed. As a result, in the welding between the electrode body and the current collector, it is possible to suppress laser welding at a place where there is an air layer between the electrode plates, so that the quality of welding between the electrode body and the current collector can be improved. It can be improved.

Further, in the temporary attachment step, the electrode plates, the electrode plates, and the current collector are temporarily attached to each other by using heat, and the electrode plates, the electrode plates, and the current collector are temporarily attached to each other. The temporary attachment portion may be formed.

According to this, in the temporary attachment step, the electrode plates are temporarily attached to each other, and the electrode plates and the current collector are temporarily attached using heat to form a temporary attachment portion. In this way, in the temporary attachment process, by temporarily attaching the plates and the current collector in addition to the plates, an air layer is generated between the plates and the current collector at the location where laser welding is performed. It can be suppressed. As a result, in the welding between the electrode body and the current collector, it is possible to suppress laser welding at a place where there is an air layer between the electrode plate and the current collector, so that the electrode body and the current collector can be suppressed. It is possible to improve the quality of welding with.

Further, in the temporary attachment step, the temporary attachment portion may be formed by using the heat generated by energizing the laminated portion with an electric current in the stacking direction.

According to this, in the temporary attachment step, the temporary attachment portion is formed by using the heat generated by applying an electric current to the laminated portion of the electrode body. As a result, the temporary attachment portion can be easily formed by performing low output resistance welding to the laminated portion, so that the quality of welding between the electrode body and the current collector can be easily improved. can.

Further, in the laser welding step, the temporary attachment portion and the current collector are laser welded so that the welded portion is formed in the region where the plates are in contact with each other when viewed from the irradiation direction of the laser beam. You may decide to do it.

According to this, in the laser welding step, the temporary attachment portion and the current collector are laser welded so that the welded portion is formed in the region where the plates are in contact with each other. By performing laser welding in the region where the plates are in contact with each other in this way, laser welding can be performed at a location where the formation of an air layer between the plates is more reliably suppressed. This makes it possible to improve the quality of welding between the electrode body and the current collector.

Further, the power storage element according to one aspect of the present invention is a power storage element including an electrode body having a laminated portion in which electrode plates are laminated in the stacking direction and a current collector bonded to the laminated portion. The joint portion between the laminated portion and the current collector is a temporary attachment portion in which the laminated plates are temporarily attached to each other in the laminated portion, and a portion in which the temporary attachment portion and the current collector are overlapped. It has a laser-welded portion in which the temporary attachment portion and the current collector are laser-welded.

According to this, in the power storage element, the joint portion between the laminated portion of the electrode body and the current collector is a temporary attachment portion in which the laminated plates are temporarily attached to each other in the laminated portion, and the temporary attachment portion and the current collector. It has a laser welded portion and a laser welded portion. In this way, the temporary attachment portion where the plates are temporarily attached and the current collector are laser welded to form the laser welded portion, so that the formation of an air layer between the plates is suppressed. So, laser welding is being performed. As a result, in the laser welded portion, it is possible to suppress laser welding at a place where there is an air layer between the electrode plates, so that the quality of welding between the electrode body and the current collector can be improved. Is done.

It should be noted that the present invention can be realized not only as a method for manufacturing such a power storage element and as a power storage element, but also as a method for joining an electrode body and a current collector, a combination of an electrode body and a current collector, or , It can also be realized as a joint portion between an electrode body and a current collector.

According to the method for manufacturing a power storage element in the present invention, it is possible to improve the quality of welding between the electrode body and the current collector.

It is a perspective view which shows the appearance of the power storage element which concerns on embodiment. It is a perspective view which shows the component arranged in the container of the power storage element which concerns on embodiment. It is an exploded perspective view which shows each component by disassembling the power storage element which concerns on embodiment. It is a front view which shows the structure in the state which the electrode body and the current collector which concerns on embodiment are joined and the joint part is formed. It is a front view and the sectional view which shows the structure of the electrode body, the current collector, the backing plate and the joint part which concerns on embodiment. It is sectional drawing which shows the method of joining the electrode body and the current collector which concerns on embodiment to form a joint part. It is a front view and sectional drawing which shows the structure of the joint part which concerns on the modification of embodiment.

Hereinafter, the power storage element and the manufacturing method thereof according to the embodiment (and its modification) of the present invention will be described with reference to the drawings. It should be noted that all of the embodiments described below are comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, in each figure, the dimensions and the like are not exactly shown. Further, in each figure, the same or similar components are designated by the same reference numerals.

In the following description and drawings, the arrangement direction of the pair of electrode terminals (positive electrode side and negative electrode side, the same applies hereinafter) of the power storage element, the arrangement direction of the pair of current collectors, or the facing direction of the short side surface of the container. It is defined as the X-axis direction. The opposite direction of the long side surface of the container, the thickness direction of the container, the stacking direction of the electrode plates at the joint between the electrode body and the current collector, the alignment direction of the current collector, the electrode body and the backing plate at the joint, or , The irradiation direction of the laser beam at the joint is defined as the Y-axis direction. The alignment direction between the container body and the lid of the power storage element, the extension direction of the leg portion (electrode body connection portion) of the current collector, or the vertical direction is defined as the Z-axis direction. These X-axis directions, Y-axis directions, and Z-axis directions intersect each other (orthogonally in the present embodiment). Depending on the usage mode, the Z-axis direction may not be the vertical direction, but for convenience of explanation, the Z-axis direction will be described below as the vertical direction.

Further, in the following description, for example, the X-axis plus direction indicates the arrow direction of the X-axis, and the X-axis minus direction indicates the direction opposite to the X-axis plus direction. The same applies to the Y-axis direction and the Z-axis direction. Further, expressions indicating relative directions or postures such as parallel and orthogonal include cases where they are not strictly the directions or postures. For example, the fact that two directions are orthogonal not only means that the two directions are completely orthogonal, but also that they are substantially orthogonal, that is, a difference of, for example, about several percent. It also means to include.

(Embodiment)
[1 General description of the power storage element 10]
First, with reference to FIGS. 1 to 3, a general description of the power storage element 10 according to the present embodiment will be given. FIG. 1 is a perspective view showing the appearance of the power storage element 10 according to the present embodiment. FIG. 2 is a perspective view showing components arranged inside the container 100 of the power storage element 10 according to the present embodiment. Specifically, FIG. 2 is a perspective view showing a configuration in a state where the container body 110 is separated from the power storage element 10, and shows a state after the current collector 400 is joined to the electrode body 300. FIG. 3 is an exploded perspective view showing each component by disassembling the power storage element 10 according to the present embodiment. Specifically, FIG. 3 is a perspective view showing components other than the container body 110 shown in FIG. 2 in an exploded manner, and shows a state before the current collector 400 is joined to the electrode body 300.

The power storage element 10 is a secondary battery (cell battery) capable of charging electricity and discharging electricity, and specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage element 10 is, for example, a battery for driving a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, or a railroad vehicle for an electric railway, or for starting an engine. Used. Examples of the above-mentioned vehicle include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline vehicle. Examples of the above-mentioned railway vehicle for electric railways include trains, monorails, linear motor cars, and hybrid trains including both diesel engines and electric motors. Further, the power storage element 10 can also be used as a stationary battery or the like used for home use, a generator, or the like.

The power storage element 10 is not limited to the non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery, or may be a capacitor. The power storage element 10 may be a primary battery that can use the stored electricity without being charged by the user, instead of the secondary battery. The power storage element 10 may be a battery using a solid electrolyte. The power storage element 10 may be a pouch-type power storage element. In the present embodiment, the power storage element 10 having a flat rectangular parallelepiped shape (square shape) is shown, but the shape of the power storage element 10 is not limited to the rectangular parallelepiped shape, and is not limited to a cylindrical shape, a long cylindrical shape, or a rectangular parallelepiped shape. It may have a rectangular parallelepiped shape or the like.

As shown in FIG. 1, the power storage element 10 includes a container 100, a pair of (positive electrode side and negative electrode side) electrode terminals 200, and a pair (positive electrode side and negative electrode side) upper gasket 210. As shown in FIGS. 2 and 3, inside the container 100, a pair (positive electrode side and negative electrode side) lower gasket 220, an electrode body 300, and a pair (positive electrode side and negative electrode side) current collector 400. (401 and 402) and a pair of backing plates 500 (positive electrode side and negative electrode side) are housed. An electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100, but the illustration is omitted. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the power storage element 10, and various types can be selected. In addition to the above components, a spacer arranged on the side or below of the electrode body 300, an insulating film for wrapping the electrode body 300, and the like may be arranged.

The container 100 is a rectangular parallelepiped (square or box-shaped) case having a container body 110 in which an opening is formed and a lid body 120 that closes the opening of the container body 110. The container main body 110 is a rectangular tubular member having a bottom that constitutes the main body portion of the container 100. The container body 110 has a pair of flat plate-shaped and rectangular short side wall portions 111 on both side surfaces (short side surfaces) in the X-axis direction, and a pair of flat plate-shaped and rectangular side surfaces (long side surfaces) on both side surfaces in the Y-axis direction. It has a long side wall portion 112 of the above, and has a flat plate-shaped and rectangular bottom wall portion 113 on the negative direction side of the Z-axis. The lid body 120 is a rectangular plate-shaped member constituting the lid portion of the container 100, and is arranged so as to extend in the X-axis direction on the Z-axis plus direction side of the container body 110. The lid 120 is provided with a gas discharge valve 121 that releases the pressure when the pressure inside the container 100 rises, a liquid injection unit 122 for injecting the electrolytic solution inside the container 100, and the like. Has been done.

With such a configuration, the container 100 has a structure in which the electrode body 300 and the like are housed inside the container body 110, and then the container body 110 and the lid body 120 are joined by welding or the like to seal the inside. ing. The material of the container 100 (container body 110 and lid 120) is not particularly limited, and may be a weldable metal such as stainless steel, aluminum, aluminum alloy, or iron, but a resin may also be used.

The electrode body 300 includes a positive electrode plate, a negative electrode plate, and a separator, and is a power storage element (power generation element) capable of storing electricity. The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on a positive electrode base material layer which is a long strip-shaped current collecting foil made of aluminum, an aluminum alloy, or the like. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on a negative electrode base material layer which is a long strip-shaped current collecting foil made of copper, a copper alloy, or the like. As the current collector foil, known materials such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, and Al—Cd alloy can also be used as appropriate. As the positive electrode active material and the negative electrode active material used for the positive electrode active material layer and the negative electrode active material layer, known materials can be appropriately used as long as they are active materials that can occlude and release lithium ions. As the separator, a microporous sheet made of resin, a non-woven fabric, or the like can be used.

The electrode body 300 is formed by laminating a positive electrode plate, a negative electrode plate, and a separator. Specifically, the electrode body 300 is formed by arranging and winding a separator between the positive electrode plate and the negative electrode plate. More specifically, in the electrode body 300, the positive electrode plate and the negative electrode plate are wound so as to be displaced from each other in the direction of the winding axis via the separator. The winding axis is a virtual axis that serves as a central axis when winding a positive electrode plate, a negative electrode plate, or the like, and in the present embodiment, a straight line passing through the center of the electrode body 300 and parallel to the X-axis direction. Is. The positive electrode plate and the negative electrode plate each have a portion (active material layer non-forming portion) where the active material is not formed (coated) and the base material layer is exposed at the end portions in the shifted directions. ..

As a result, the electrode body 300 has a laminated portion 320 on the positive electrode side in which the active material layer non-forming portion of the positive electrode plate is laminated and bundled at one end in the winding axis direction, and the other end in the winding axis direction. The portion has a laminated portion 320 on the negative electrode side in which the active material layer non-forming portion of the negative electrode plate is laminated and bundled. The laminated portion 320 is a portion where the electrode plates (positive electrode plate or negative electrode plate) are laminated in the laminating direction (Y-axis direction). That is, the electrode body 300 includes an electrode body main body 310 constituting the main body of the electrode body 300 and a pair of laminated portions 320 (positive electrode side and negative electrode side) protruding from the electrode body main body 310 on both sides in the X-axis direction. Have. The electrode body main body 310 is an oval-shaped portion (active material layer forming portion) formed by winding a separator and a portion of the positive electrode plate and the negative electrode plate on which the active material layer is formed (coated). .. In the present embodiment, the cross-sectional shape of the electrode body 300 (electrode body main body 310) is shown as an oval shape, but a circular shape, an elliptical shape, a polygonal shape, or the like may be used.

The electrode terminal 200 is a terminal member (positive electrode terminal and negative electrode terminal) electrically connected to the electrode body 300 via the current collector 400. That is, the electrode terminal 200 leads the electricity stored in the electrode body 300 to the external space of the power storage element 10, and also introduces electricity into the internal space of the power storage element 10 in order to store electricity in the electrode body 300. It is a metal member of. The electrode terminal 200 is formed of a conductive member such as aluminum, an aluminum alloy, copper, or a metal such as a copper alloy. The electrode terminal 200 is connected (bonded) to the current collector 400 by caulking or the like, and is attached to the lid body 120.

Specifically, as shown in FIG. 3, in the electrode terminal 200, the shaft portion 201 collects the through hole 211 of the upper gasket 210, the through hole 123 of the lid 120, and the through hole 221 of the lower gasket 220. By being inserted into the through hole 411 of the electric body 400 and crimped, it is fixed to the lid 120 together with the current collector 400. The method of connecting (bonding) the electrode terminal 200 and the current collector 400 is not limited to caulking, and is not limited to ultrasonic bonding, welding such as laser welding or resistance welding, or caulking such as screw fastening. Mechanical bonding or the like may be used.

The upper gasket 210 is arranged between the lid 120 of the container 100 and the electrode terminal 200, and is a plate-shaped and rectangular member (upper part of the positive electrode) that insulates and seals between the lid 120 and the electrode terminal 200. Gasket and negative electrode upper gasket). A through hole 211 into which the shaft portion 201 of the above-mentioned electrode terminal 200 is inserted is formed in the central portion of the upper gasket 210. The lower gasket 220 is arranged between the lid 120 of the container 100 and the current collector 400, and is a plate-shaped and rectangular member (positive positive lower gasket and negative electrode) that insulates between the lid 120 and the current collector 400. Lower gasket). A through hole 221 into which the shaft portion 201 of the above-mentioned electrode terminal 200 is inserted is formed in the central portion of the lower gasket 220.

The upper gasket 210 and the lower gasket 220 may be made of any material as long as they have insulating properties. For example, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin ( PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene / perfluoroalkyl vinyl ether (PFA), poly It is formed of an insulating member such as tetrafluoroethylene (PTFE), polyether sulfone (PES), ABS resin, or a composite material thereof.

The current collector 400 is arranged on both sides of the electrode body 300 in the X-axis direction, is connected (bonded) to the laminated portion 320 of the electrode body 300 and the electrode terminal 200, and electrically connects the electrode body 300 and the electrode terminal 200. It is a current collector member (positive electrode current collector and negative electrode current collector) having conductivity and rigidity to be connected. Specifically, the current collector 400 is a plate-shaped member arranged in a bent state along the side wall and the lid 120 from the side wall of the container body 110 to the lid 120. Further, the current collector 400 is fixedly connected (joined) to the lid 120. With this configuration, the electrode body 300 is held (supported) in a state of being suspended from the lid body 120 by the current collector 400, and vibration due to vibration, impact, or the like is suppressed. The material of the current collector 400 is not particularly limited, but for example, the current collector 400 on the positive electrode side is formed of aluminum or an aluminum alloy, like the positive electrode base material layer of the electrode body 300, and the current collector 400 on the negative electrode side is formed. Is made of copper, a copper alloy, or the like, like the negative electrode base material layer of the electrode body 300.

As shown in FIG. 3, of the positive electrode side and negative electrode side current collectors 400, the current collector 401 on the X-axis plus direction side and the current collector 402 on the X-axis minus direction side are symmetrical with respect to the YZ plane. Has a unique shape. Each of the current collectors 400 (current collectors 401 and 402) has a terminal connection portion 410 and an electrode connection portion 420 extending from the terminal connection portion 410 in the negative direction of the Z axis. There is.

The terminal connection portion 410 is the base of the current collector 400 connected (bonded) to the electrode terminal 200. Specifically, the terminal connection portion 410 is parallel to the XY plane on which the above-mentioned circular through hole 411 is formed, which is arranged on the electrode terminal 200 side (upper side, Z-axis plus direction) of the current collector 400. It is a flat plate-shaped portion and is electrically and mechanically connected (bonded) to the electrode terminal 200. The electrode connecting portion 420 is a leg portion of the current collector 400 connected (bonded) to the electrode body 300. That is, the electrode connecting portion 420 is a portion of the current collector 400 arranged on the electrode body 300 side (lower side, Z-axis minus direction), and is electrically and mechanically connected (bonded) to the electrode body 300. .. Specifically, the electrode connecting portion 420 is a long and flat plate-shaped portion extending in the negative direction of the Z axis from the positive end of the terminal connecting portion 410 in the positive direction of the Y axis, and the Y of the laminated portion 320 of the electrode body 300. It is arranged in the positive direction of the axis and is joined to the laminated portion 320.

The backing plate 500 is a member that is arranged at a position where the electrode body 300 is sandwiched between the current collector 400 and is joined to the electrode body 300 together with the current collector 400 in a state where the electrode body 300 is sandwiched between the current collector 400 and the current collector 400. be. That is, the backing plate 500 is a cover that protects the laminated portion 320, which is arranged at a position sandwiching the laminated portion 320 with the electrode connecting portion 420. Specifically, the backing plate 500 is a flat plate-shaped and rectangular metal member that is arranged in the Y-axis minus direction of the laminated portion 320 and extends in the Z-axis direction along the laminated portion 320. The material of the backing plate 500 is not particularly limited, but for example, the backing plate 500 on the positive electrode side is formed of aluminum or an aluminum alloy, like the positive electrode base material layer of the electrode body 300, and the backing plate 500 on the negative electrode side is an electrode. Like the negative electrode base material layer of the body 300, it is made of copper, a copper alloy, or the like.

With such a configuration, the electrode connection portion 420, the laminated portion 320, and the backing plate 500 are joined to each other with the laminated portion 320 sandwiched between the electrode connecting portion 420 and the backing plate 500, and the joining portion 700 (see FIG. 2). ) Is formed. In the present embodiment, two joints 700 arranged in the Z-axis direction are formed for one electrode connection portion 420. That is, two junctions 700 are formed in one current collector 400, and four junctions 700 are formed in one storage element 10.

[2 Explanation of joint 700]
[2.1 Explanation of the configuration of the joint 700]
Next, the configuration of the joint portion 700 between the laminated portion 320 of the electrode body 300 and the electrode connection portion 420 of the current collector 400 will be described in detail. FIG. 4 is a front view showing a configuration in a state where the electrode body 300 and the current collector 400 according to the present embodiment are joined to form a joint portion 700. Specifically, FIG. 4 is a plan view showing a configuration when the state shown in FIG. 2 is viewed from the Y-axis minus direction. FIG. 5 is a front view and a cross-sectional view showing the configurations of the electrode body 300, the current collector 400, the backing plate 500, and the joint portion 700 according to the present embodiment. Specifically, FIG. 5A is a front view showing an enlarged structure of the joint portion 700 shown in FIG. 4 and its surroundings, and FIG. 5B is an enlarged front view, and FIG. 5B is FIG. 5A. It is sectional drawing which shows the structure when the structure of is cut by the cross section of V (b) -V (b). Note that FIG. 5 shows the configuration of the joint portion 700 on the X-axis plus direction side and its surroundings among the joint portions 700 shown in FIG. 4, but other joint portions 700 and their surrounding configurations are also shown. It has a similar configuration.

As shown in these figures, the electrode connection portion 420 of the current collector 400 is arranged in the Y-axis positive direction of the laminated portion 320 of the electrode body 300, and the backing plate 500 is arranged in the Y-axis negative direction of the laminated portion 320. A joint portion 700 to which the electrode body 300, the current collector 400, and the backing plate 500 are joined is formed. As shown in FIG. 5, the joint portion 700 has a temporary attachment portion 710 and a laser welded portion 720.

The temporary attachment portion 710 is a portion where the electrode plates 301 laminated in the laminated portion 320 are temporarily attached (temporarily fixed) to each other. The electrode plate 301 is a positive electrode plate or a negative electrode plate, and more specifically, is a base material layer (active material layer non-forming portion) of the positive electrode plate or the negative electrode plate. Temporarily attaching (temporarily fixing) the electrode plates 301 does not mean that the electrode plates 301 are firmly joined to each other, but the electrode plates 301 are joined to each other with a weak force, and the electrode plates 301 are in contact with each other at least temporarily. (A state in which the formation of a gap between the electrode plates 301 is suppressed). For example, the surface of the electrode plate 301 is melted without melting to the inside of the electrode plate 301, and the electrode plates 301 are joined to each other with a weak force. As a result, the temporary attachment portion 710 may be in a state where the electrode plates 301 are in contact with each other as a whole, or may be in a state where the electrode plates 301 are in contact with each other only in a part thereof.

Specifically, a bulging portion 510 having a circular shape when viewed from the Y-axis direction and bulging in the Y-axis plus direction is formed at a position corresponding to the temporary attachment portion 710 of the backing plate 500. The bulging portion 510 is a bulging portion in which the surface of the backing plate 500 in the plus direction of the Y axis protrudes in the plus direction of the Y axis and the surface in the minus direction of the Y axis is recessed in the plus direction of the Y axis. The bulging portion 510 is formed on the backing plate 500, and the surface of the laminated portion 320 in the negative direction in the Y-axis direction is recessed. It is a part. That is, in the temporary attachment portion 710, the electrode plates 301 are pressed against each other in the Y-axis direction and temporarily attached.

In the present embodiment, in addition to the electrode plates 301, the electrode plate 301 at the end in the plus direction of the Y-axis included in the laminated portion 320 and the electrode connecting portion 420 of the current collector 400 are also temporarily attached. Further, the electrode plate 301 at the end in the minus direction of the Y-axis included in the laminated portion 320 and the bulging portion 510 of the backing plate 500 are also temporarily attached. That is, the temporary attachment portion 710 is a portion where the electrode plates 301 are temporarily attached to each other, the electrode plates 301 and the current collector 400, and the electrode plates 301 and the backing plate 500 are temporarily attached. Specifically, the temporary attachment portion 710 is a portion where the electrode plates 301, the electrode plates 301 and the current collector 400, and the electrode plates 301 and the backing plate 500 are pressure-welded and temporarily attached. More specifically, the temporary attachment portion 710 is a portion that is pressure-welded and temporarily attached using heat, and the details will be described later.

The laser welded portion 720 is a welded portion formed by laser welding the temporary attachment portion 710 and the current collector 400 at a portion where the temporary attachment portion 710 and the current collector 400 are overlapped with each other. Specifically, in the laser welded portion 720, the temporary attachment portion 710 and the facing portion 421 are laser-welded at the portion where the temporary attachment portion 710 and the facing portion 421 of the electrode connection portion 420 of the current collector 400 are overlapped with each other. It is a laser welding mark formed by the above. The facing portion 421 is a columnar portion of the electrode connecting portion 420 facing the temporary attachment portion 710 in the Y-axis direction. In the present embodiment, the laser welded portion 720 is a laser weld mark formed by laser welding the bulging portion 510 of the backing plate 500, the temporary attachment portion 710, and the facing portion 421.

Specifically, the laser welded portion 720 is formed in a region where the electrode plates 301 are in contact with each other when viewed from the Y-axis direction. More specifically, the laser welded portion 720 is formed in a region where the electrode plates 301 are in contact with each other, the electrode plates 301 and the facing portion 421, and the electrode plates 301 and the bulging portion 510 are in contact with each other. In the present embodiment, the laser welded portion 720 is formed at the central portion of the temporary attachment portion 710 (the central portion of the facing portion 421 and the bulging portion 510) when viewed from the Y-axis direction. Further, the laser welded portion 720 is a melting mark that penetrates the temporary attachment portion 710 from the surface of the bulging portion 510 in the minus direction of the Y axis and melts to the inside of the facing portion 421.

In the current collector 400, the facing portion 421 is pressure-welded in the Y-axis direction, so that pressure-welding marks (not shown) such as recesses are formed on both sides of the facing portion 421 in the Y-axis direction. That is, in the current collector 400, the facing portion 421 does not protrude in the Y-axis direction from the periphery of the facing portion 421. In the current collector 400, pressure contact marks are not formed on both sides of the facing portion 421 in the Y-axis direction, and both sides in the Y-axis direction may be flat.

[2.2 Description of Method for Forming Joint 700]
Next, among the methods for manufacturing the power storage element 10, the method for forming the joint portion 700 described above, that is, the method for joining the electrode body 300 and the current collector 400 will be described in detail. FIG. 6 is a cross-sectional view showing a method of joining the electrode body 300 and the current collector 400 according to the present embodiment to form a joint portion 700. Specifically, FIG. 6A shows a state before the temporary attachment step in the method for manufacturing the power storage element 10 (method for forming the joint portion 700), and FIG. 6B shows the temporary attachment step. 6 (c) shows a laser welding process.

First, as shown in FIG. 6A, the current collector 400 is arranged on the electrode body 300. Specifically, the electrode connection portion 420 of the current collector 400 is arranged in the Y-axis plus direction of the laminated portion 320 of the electrode body 300, and the backing plate 500 is arranged in the Y-axis minus direction of the laminated portion 320. The 320 is sandwiched between the electrode connecting portion 420 and the backing plate 500 in the stacking direction (Y-axis direction) of the electrode plates 301.

Then, as shown in FIG. 6B, as a temporary attachment step, the electrode plates 301 laminated in the laminated portion 320 are temporarily attached to each other by using heat, and the temporary attachment portions to which the electrode plates 301 are temporarily attached to each other are temporarily attached. Form 710. Specifically, in the temporary attachment process, the electrode plates 301, the electrode plates 301, and the current collector 400 are temporarily attached to each other by using heat, and the electrode plates 301, the electrode plates 301, and the current collector 400 are attached to each other. The temporarily attached temporary attachment portion 710 is formed. More specifically, in the temporary attachment step, the temporary attachment portion 710 is formed by using the heat generated by energizing the laminated portion 320 with an electric current in the stacking direction.

In the present embodiment, with the laminated portion 320 sandwiched between the electrode connecting portion 420 and the backing plate 500, the temporary attachment device 20 (in the Y-axis plus direction of the electrode connecting portion 420 and the Y-axis minus direction of the backing plate 500) 21 and 22) are arranged. The temporary attachment device 20 is, for example, an electrode for resistance welding (an electrode tip tip made of tungsten). Specifically, the temporary attachment device 21 is arranged on the backing plate 500 side, and the temporary attachment instrument 22 is arranged on the electrode connection portion 420 side, so that the temporary attachment instrument 21 and the temporary attachment instrument 22 are brought close to each other. The backing plate 500, the laminated portion 320, and the electrode connecting portion 420 are pressure-welded (compressed). As a result, the bulging portion 510 is formed on the backing plate 500, and a thin portion is formed at a position facing the bulging portion 510 of the laminated portion 320.

Further, a current I having a current value smaller than that during normal resistance welding flows between the temporary attachment device 21 and the temporary attachment device 22, so that a current I flows between the bulging portion 510 and the facing portion 421. Therefore, relatively low temperature heat is generated, and low output resistance welding is performed. The smaller the current value of the current I is, the more preferable it is. By resistance welding, between the electrode plates 301 in the laminated portion 320, between the electrode plates 301 and the facing portion 421, and between the electrode plates 301 and the bulging portion 510. It is preferable that the current value is such that there is no gap. As a result, a temporary attachment portion 710 is formed in which the electrode plates 301 in the laminated portion 320, the electrode plates 301 and the facing portion 421, and the electrode plate 301 and the bulging portion 510 are resistance welded at a low output and temporarily attached. Will be done.

Next, as shown in FIG. 6 (c), as a laser welding step, the laser beam L is irradiated toward the portion where the temporary attachment portion 710 and the current collector 400 are overlapped, and the temporary attachment portion 710 and the current collector 400 are collected. Laser welded to the electric body 400 to form a laser welded portion 720. Specifically, in the laser welding step, the temporary attachment portion 710 and the current collector 400 are provided so that the welded portion is formed in the region where the electrode plates 301 are in contact with each other when viewed from the irradiation direction of the laser beam L. Laser welding. More specifically, in the laser welding process, in the region where the electrode plates 301 are in contact with each other, the electrode plates 301 and the current collector 400, and the electrode plates 301 and the backing plate 500 are in contact with each other when viewed from the irradiation direction of the laser beam L. The temporary attachment portion 710 and the current collector 400 are laser-welded so that the welded portion is formed on the surface.

In the present embodiment, when viewed from the irradiation direction (Y-axis direction) of the laser beam L, the central portion of the bulging portion 510, the temporary attachment portion 710, and the facing portion 421 is with the electrode plates 301 in the temporary attachment portion 710. , The electrode plate 301 and the facing portion 421 are in contact with the electrode plate 301 and the bulging portion 510. Therefore, when viewed from the irradiation direction (Y-axis direction) of the laser beam L, the laser is applied to the central portion of the bulging portion 510, the temporary attachment portion 710, and the facing portion 421 from the bulging portion 510 side toward the Y-axis plus direction. Light L is irradiated. As a result, the bulging portion 510, the temporary attachment portion 710, and the facing portion 421 are laser welded to form the laser welded portion 720.

The laser welded portion 720 is a portion where the bulging portion 510, the temporary attachment portion 710, and the facing portion 421 are melted and integrated. In the present embodiment, when viewed from the Y-axis direction, the central portion of the bulging portion 510, the central portion of the temporary attachment portion 710, and the central portion of the facing portion 421 and the portion on the temporary attachment portion 710 side are melted. , Laser welded portion 720 is formed. Specifically, the bulging portion 510, the temporary attachment portion 710, and the facing portion 421 are laser-welded by keyhole (deep penetration) welding. Keyhole (deep penetration) welding is a method of forming a welded portion with a narrow bead width and deep penetration by increasing the power density of the laser beam and forming a keyhole in the material. As a result, the temporary attachment portion 710 and the current collector 400 can be spot-welded to a deep position at high speed.

[3 Explanation of effect]
As described above, in the method for manufacturing the power storage element 10 according to the embodiment of the present invention, the electrode plates 301 laminated in the laminated portion 320 of the electrode body 300 are temporarily attached to each other by using heat to form the temporary attachment portion 710. The temporary attachment step is included, and a laser welding step of laser welding the temporary attachment portion 710 and the current collector 400 is included. In this way, by temporarily attaching the electrode plates 301 of the laminated portion 320 to each other using heat to form the temporary attachment portion 710, the poles can be formed without using a complicated device or jig for holding the electrode plates 301. It is possible to easily suppress the formation of an air layer between the plates 301. Further, by laser welding the temporary attachment portion 710 and the current collector 400, laser welding can be performed at a position where the formation of an air layer between the electrode plates 301 is suppressed. As a result, in the welding between the electrode body 300 and the current collector 400, it is possible to suppress laser welding at a place where there is an air layer between the electrode plates 301. Therefore, the electrode body 300 and the current collector 400 It is possible to improve the quality of welding.

Further, in the temporary attachment step, the electrode plates 301, the electrode plates 301, and the current collector 400 are temporarily attached using heat to form the temporary attachment portion 710. In this way, in the temporary attachment process, by temporarily attaching the electrode plates 301 and the current collector 400 in addition to the electrode plates 301, air is provided between the electrode plates 301 and the current collector 400 at the location where laser welding is performed. It is possible to suppress the formation of layers. As a result, in the welding of the electrode body 300 and the current collector 400, it is possible to suppress laser welding at a position where there is an air layer between the electrode plate 301 and the current collector 400, so that the electrode body can be suppressed. It is possible to improve the quality of welding between the 300 and the current collector 400.

Further, in the temporary attachment step, the temporary attachment portion 710 is formed by using the heat generated by energizing the laminated portion 320 of the electrode body 300 with the current I. As a result, the temporary attachment portion 710 can be easily formed by performing low output resistance welding to the laminated portion 320, so that the quality of welding between the electrode body 300 and the current collector 400 described above is improved. It is possible to easily realize the configuration for this purpose. Further, by performing resistance welding at a low output, wear of an electrode for resistance welding (temporary attachment 20 or the like) can be suppressed, so that the frequency of replacement of the electrode can be lengthened. Further, by performing resistance welding at a low output, it is possible to suppress the generation of heat at the time of temporary attachment, so that the influence on the electrode body 300 (particularly the separator) and the like (for example, the separator melts) is reduced. be able to.

Further, in the laser welding step, the temporary attachment portion 710 and the current collector 400 are laser welded so that the welded portion is formed in the region where the electrode plates 301 are in contact with each other. By performing laser welding in the region where the electrode plates 301 are in contact with each other in this way, laser welding can be performed at a position where the formation of an air layer between the electrode plates 301 is more reliably suppressed. As a result, the quality of welding between the electrode body 300 and the current collector 400 can be improved.

Further, according to the power storage element 10 according to the embodiment of the present invention, the joint portion 700 between the laminated portion 320 of the electrode body 300 and the current collector 400 is temporarily attached to the electrode plates 301 laminated in the laminated portion 320. It has a temporary attachment portion 710, and a laser welding portion 720 in which the temporary attachment portion 710 and the current collector 400 are laser-welded. In this way, the temporary attachment portion 710 to which the electrode plates 301 are temporarily attached to each other and the current collector 400 are laser welded to form the laser welded portion 720, so that an air layer is generated between the electrode plates 301. Laser welding is performed at the place where the pressure is suppressed. As a result, in the laser welded portion 720, it is possible to suppress laser welding at a place where there is an air layer between the electrode plates 301, so that the quality of welding between the electrode body 300 and the current collector 400 can be improved. We are able to improve.

Further, in the current collector 400, both sides of the facing portion 421 facing the temporary attachment portion 710 do not protrude from the periphery of the facing portion 421. Therefore, in order to form the temporary attachment portion 710, it can be inferred that a simple method using heat or the like was performed instead of a strong joint that deforms the current collector 400 such as a caulking joint. .. By simply forming the temporary attachment portion 710 in this way, it is possible to easily improve the welding quality of the electrode body 300 and the current collector 400.

[4 Explanation of modified example]
Next, a modified example of the above embodiment will be described. FIG. 7 is a front view and a cross-sectional view showing the configuration of the joint portion 701 according to the modified example of the present embodiment. Specifically, FIG. 7 is a diagram corresponding to FIG.

As shown in FIG. 7, the joint portion 701 in this modification has a laser welded portion 721 instead of the laser welded portion 720 of the joint portion 700 in the above embodiment. The laser welded portion 721 has a larger area when viewed from the Y-axis direction than the laser welded portion 720 in the above embodiment. That is, in the above embodiment, the temporary attachment portion 710 and the current collector 400 are laser welded by keyhole (deep penetration) welding to form the laser welded portion 720. The temporary attachment portion 710 and the current collector 400 are laser welded by heat conduction welding to form the laser welded portion 721. Thermal conduction welding is a method of forming a welded portion with a wide bead width by absorbing laser light with a relatively low power density on the surface of the material, converting it into heat, melting it, cooling it, and hardening it.

The laser welded portion 721 may have a welding depth in the Y-axis direction equivalent to that of the laser welded portion 720 or shallower than that of the laser welded portion 720. Since other configurations of this modification are the same as those of the above embodiment, detailed description thereof will be omitted.

As described above, according to the power storage element and the manufacturing method thereof according to the present modification, the same effect as that of the above-described embodiment can be obtained. In particular, in this modification, since the temporary attachment portion 710 and the current collector 400 are laser-welded by heat conduction welding, it takes some time for welding, but spatter is less likely to occur during welding. Further, since the laser welded portion 721 having a relatively large volume is formed, the electrical and mechanical stability of the junction at the junction portion 701 can be improved. As a result, the quality of welding between the electrode body 300 and the current collector 400 can be improved.

(Other variants)
Although the power storage element and the manufacturing method thereof according to the embodiment of the present invention (including its modification) have been described above, the present invention is not limited to this embodiment. That is, the embodiments disclosed this time are exemplified in all respects, the scope of the present invention is shown by the scope of claims, and includes all modifications within the meaning and scope equivalent to the scope of claims. ..

For example, in the above embodiment, the electrode plates 301 are pressed against each other, the electrode plates 301 and the current collector 400, and the electrode plates 301 and the backing plate 500 are pressed against each other, and heat is applied to temporarily attach them. However, heat may be applied to temporarily attach them without pressing them together. In this case, the backing plate 500 may not have the bulging portion 510 formed.

In the above embodiment, the electrode plates 301 are temporarily attached to each other, the electrode plates 301 and the current collector 400, and the electrode plates 301 and the backing plate 500 are temporarily attached. However, the electrode plate 301 and the current collector 400 may not be temporarily attached, and the electrode plate 301 and the backing plate 500 may not be temporarily attached. That is, after the electrode plates 301 in the laminated portion 320 are temporarily attached to each other, the current collector 400 and the backing plate 500 may be superposed on the laminated portion 320 and laser welded. It is preferable to temporarily attach the electrode plate 301 and the current collector 400, and the electrode plate 301 and the backing plate 500, but even if these are not temporarily attached, if the electrode plates 301 are temporarily attached to each other, the electrode body 300 and the electrode body 300 can be attached. It is possible to obtain the effect of improving the quality of welding with the current collector 400.

In the above embodiment, the heat generated by energizing the electric current is used to form the temporary attachment portion 710. However, the temporary attachment portion 710 may be formed by using heat without energizing the electric current. For example, the temporary attachment portion 710 may be formed by using heat generated by ultrasonic bonding at a low output or by sandwiching it with a heated instrument. When ultrasonic bonding is performed, it is preferable to use a horn having a flat surface in contact with the electrode plate 301, whereby a region that can be temporarily attached can be increased. Alternatively, if the temporary attachment can be performed without using heat, the temporary attachment portion 710 may be formed without using heat. In these cases, the temporary attachment portion 710 may be formed by solid-phase joining the electrode plates 301 to each other.

In the above embodiment, the laser beam L is irradiated from the backing plate 500 (bulging portion 510) side to form the joint portion 700 (or 701). However, the laser beam L may be irradiated from the current collector 400 (electrode connection portion 420) side to form the joint portion 700 (or 701).

In the above embodiment, the laser welded portion 720 (or 721) is located in a region where the electrode plates 301 and the like are in contact with each other when viewed from the irradiation direction (Y-axis direction) of the laser beam L, specifically, a temporary attachment portion. It was decided that it was formed in the central part of 710. However, the laser welded portion 720 (or 721) may be formed at the end portion or the like of the temporary attachment portion 710 as long as the electrode plates 301 or the like are in contact with each other at the end portion or the like of the temporary attachment portion 710. Further, the laser welded portion 720 (or 721) may be formed outside the region where the electrode plates 301 and the like are in contact with each other.

In the above embodiment, one electrode connection portion 420 is provided in the current collector 400, one backing plate 500 is arranged for one electrode connection portion 420, and two joint portions 700 (or 701) are arranged. ) Was to be formed. However, the number of electrode connection portions 420 provided in the current collector 400, the number of joint portions 700 (or 701) formed in one electrode connection portion 420, and the backing plate arranged in one electrode connection portion 420. The number of 500 sheets is not particularly limited.

In the above embodiment, the bulging portion 510, the facing portion 421, the joining portion 700 (or 701), the temporary attachment portion 710, the laser welded portion 720 (or 721), and the like have a circular shape when viewed from the Y-axis direction. I decided to have it. However, these shapes are not particularly limited, and may be an elliptical shape, an oval shape, a rectangular shape, or any other polygonal shape when viewed from the Y-axis direction.

In the above embodiment, the current collector 400, the electrode body 300, and the backing plate 500 are joined, but members other than these may also be joined together. Alternatively, the backing plate 500 may not be provided, and the electrode body 300 and the current collector 400 may be joined.

In the above embodiment, the electrode body 300 is a so-called vertically wound winding type electrode body whose winding axis is parallel to the lid body 120. However, the electrode body 300 may be a so-called horizontal winding type electrode body in which the winding axis is perpendicular to the lid body 120. Further, the shape of the electrode body 300 is not limited to the winding type, but is a stack type in which flat plate-shaped electrode plates are laminated, or a shape in which the electrode plate and / or the separator is folded in a bellows shape (rectangular pole with the separator in a bellows shape). It may be in a form of sandwiching a plate, a form in which a plate and a separator are overlapped and then formed into a bellows shape, etc.). In this case, the laminated portion 320 may be a tab protruding from the electrode body main body portion 310 of the electrode body 300.

In the above embodiment, the above configuration is applied to all the joints 700 (or 701), but the above configuration is not applied to any of the joints 700 (or 701). good.

Also included within the scope of the present invention is a form constructed by arbitrarily combining the components included in the above-described embodiment and its modifications.

The present invention can be realized not only as a method for manufacturing such a power storage element and as a power storage element, but also a method for joining the electrode body 300 and the current collector 400, and a combination of the electrode body 300 and the current collector 400. Alternatively, it can also be realized as a joint portion between the electrode body 300 and the current collector 400.

The present invention can be applied to a method for manufacturing a power storage element such as a lithium ion secondary battery.

10 Power storage element 20, 21, 22 Temporary attachment 100 Container 110 Container body 120 Lid body 200 Electrode terminal 300 Electrode body 301 Electrode plate 310 Electrode body body 320 Laminated part 400, 401, 402 Current collector 410 Terminal connection part 420 Electrode Connection part 421 Opposite part 500 Support plate 510 Swelling part 700, 701 Joint part 710 Temporary attachment part 720, 721 Laser welded part

Claims (5)

A method for manufacturing a power storage element including an electrode body having a laminated portion in which electrode plates are laminated in a laminated direction and a current collector bonded to the laminated portion.
A temporary attachment step of temporarily attaching the laminated electrode plates to each other in the laminated portion by using heat to form a temporary attachment portion to which the electrode plates are temporarily attached to each other.
A laser welding step of irradiating a portion where the temporary attachment portion and the current collector are overlapped with a laser beam and laser welding the temporary attachment portion and the current collector.
A method for manufacturing a power storage element including. In the temporary attachment step, the plates, the plates, and the current collector are temporarily attached to each other by using heat, and the plates, the plates, and the current collector are temporarily attached to each other. The method for manufacturing a power storage element according to claim 1, wherein the temporary attachment portion is formed. The method for manufacturing a power storage element according to claim 1 or 2, wherein in the temporary attachment step, heat generated by energizing the laminated portion with an electric current in the stacking direction is used to form the temporary attachment portion. In the laser welding step, the temporary attachment portion and the current collector are laser welded so that a welded portion is formed in a region where the electrode plates are in contact with each other when viewed from the irradiation direction of the laser beam. Item 6. The method for manufacturing a power storage element according to any one of Items 1 to 3. A power storage element including an electrode body having a laminated portion in which electrode plates are laminated in the stacking direction and a current collector bonded to the laminated portion.
The joint between the laminated portion and the current collector is
A temporary attachment portion in which the laminated plates are temporarily attached to each other in the laminated portion, and a temporary attachment portion.
A power storage element having a laser-welded portion in which the temporary attachment portion and the current collector are laser-welded in a portion where the temporary attachment portion and the current collector are overlapped.

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