WO2014163184A1 - Structure de collecteur de batterie rechargeable et procédé permettant de former une structure de collecteur de batterie rechargeable - Google Patents

Structure de collecteur de batterie rechargeable et procédé permettant de former une structure de collecteur de batterie rechargeable Download PDF

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Publication number
WO2014163184A1
WO2014163184A1 PCT/JP2014/059960 JP2014059960W WO2014163184A1 WO 2014163184 A1 WO2014163184 A1 WO 2014163184A1 JP 2014059960 W JP2014059960 W JP 2014059960W WO 2014163184 A1 WO2014163184 A1 WO 2014163184A1
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WIPO (PCT)
Prior art keywords
current collecting
stirring
secondary battery
current collector
current
Prior art date
Application number
PCT/JP2014/059960
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English (en)
Japanese (ja)
Inventor
田中　明
雄輔 内田
平野　聡
章弘 佐藤
賢一 岡本
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新神戸電機株式会社
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Priority to JP2015510156A priority Critical patent/JP5943146B2/ja
Publication of WO2014163184A1 publication Critical patent/WO2014163184A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/54—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/12—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding
    • B23K20/122—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding using a non-consumable tool, e.g. friction stir welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/176—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for prismatic or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/547—Terminals characterised by the disposition of the terminals on the cells
    • H01M50/55—Terminals characterised by the disposition of the terminals on the cells on the same side of the cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/552—Terminals characterised by their shape
    • H01M50/553—Terminals adapted for prismatic, pouch or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/562—Terminals characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/564—Terminals characterised by their manufacturing process
    • H01M50/567—Terminals characterised by their manufacturing process by fixing means, e.g. screws, rivets or bolts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a current collection structure for a secondary battery and a method for forming a current collection structure for a secondary battery.
  • Non-aqueous electrolyte secondary batteries such as lithium-ion batteries are suitable for increasing the energy density, and thus include not only small electronic devices such as mobile phones and personal computers, but also hybrid electric vehicles (HEV) and electric vehicles (EV). ), Applications are expanding from mobile power sources such as forklifts and shovel cars to large storage batteries such as UPS (uninterruptible power supply), solar power generation and wind power generation. With such expansion of industrial applications, secondary batteries such as lithium ion batteries are required to have a large capacity and a large current.
  • a secondary battery such as a lithium ion battery has a structure in which a plurality of current collecting tabs extending from an electrode plate group are electrically connected to a current collector of a terminal.
  • the number of current collecting tabs to be stacked In order to increase the capacity or current of the secondary battery having such a structure, the number of current collecting tabs to be stacked must be increased. However, if the number of stacked current collecting tabs is increased, heat is likely to be generated between the current collecting tabs or at the connecting portions between the current collecting tabs and the terminals. In the conventional secondary battery, in order to prevent heat generation due to such an increase in the number of stacked current collecting tabs, the current collecting tabs are connected to the terminals so that the electrical resistance of the connecting portion between the current collecting tabs and the terminals is as small as possible. A directly joined current collecting structure is adopted.
  • a current collecting tab is disposed between a concave portion formed on a current collector plate of a terminal and a convex portion that is formed on a contact plate and engages with a concave portion of the current collector plate.
  • a technique for directly joining a current collecting tab to a current collecting plate of a terminal by fixing this with a screw is disclosed.
  • a plurality of current collecting tabs are sandwiched between a current collecting plate and a contact plate of a terminal, and the current collecting tabs are directly joined to the current collecting plate of the terminal by welding them with a laser. Techniques to do this are disclosed.
  • Patent Document 3 discloses a technique for directly joining a current collecting tab to a current collecting plate of a terminal by sandwiching the current collecting tab between a current collecting plate and a contact plate and performing friction stir welding. ing.
  • Patent Document 4 discloses that friction stir welding (FSW) can be used as a joining technique used for batteries.
  • FSW friction stir welding
  • the spatter generated during welding melts the separator or remains in the electrode group, causing a short circuit.
  • the laser beam diameter is usually as small as ⁇ 1 mm or less, even if such laser welding is used, it is not possible to obtain a sufficient bonding area for flowing a large current.
  • the contact resistance can be reduced as compared with the mechanical joining such as screw fixing, and the joining width and the joining area as compared with the joining by laser welding.
  • a rotating tool is pressed against the stacked current collecting tabs, so thin foils are stacked and joined together like current collecting tabs.
  • the current collecting tab is displaced during the joint, resulting in poor contact.
  • the inventor has found that when the pressing plate, the current collecting tab layer, and the current collector are joined by friction stir welding, a relatively large variation occurs in the resistance value of the joined portion. When the discharge current is small, the variation in resistance value does not become a big problem. However, in a large-capacity type secondary battery that discharges a large current, a slight variation in resistance value causes abnormal heat generation of terminals.
  • An object of the present invention is to provide a current collecting structure for a secondary battery and a method for forming a current collecting structure for a secondary battery, which can reduce the resistance value of a junction between a current collector of a terminal and a plurality of current collecting tabs. It is in.
  • the current collector structure of the secondary battery to be improved by the present invention includes a terminal having a current collector and a plurality of current collecting tabs extending from a group of electrode plates in which a plurality of electrode plates are laminated via a separator. And a metal pressing plate that sandwiches the current collecting tab layer between the current collecting tab layer and the current collector.
  • the current collector, the current collecting tab layer, and the pressing plate are joined by friction stir welding.
  • the friction stir welding means rotating the tool by softening the joining member by the frictional heat generated by pressing the cylindrical stir welding rotating tool with protrusions on the tip against the joining member while rotating. This is a method in which the joining members are integrated by plastically flowing around the joint with force and kneading.
  • the current collecting tab layer is exposed on the surface of one or more stirring joints formed by joining the holding plate, the current collecting tab layer, and the current collector by friction stir welding. Not done.
  • the stirring joint used in the present invention has a space extending from the holding plate side to the current collector, and the portion of the stirring joint surrounding this space is formed by the plastic fluid metal of the holding plate, the holding plate and the current collecting tab.
  • the holding plate and the current collector are made of the plastic fluidized metal obtained by stirring, the plastic flowing metal obtained by stirring the holding plate, the current collecting tab and the current collector, and the plastic flowing metal obtained by stirring the current collecting tab and the current collector. It is preferable to form continuously between these. In other words, the part of the stir welding portion surrounding the space formed by the rotating stir welding rotating tool is all made of plastic fluidized metal.
  • the friction stir welding may be either a spot type friction stir welding performed by positioning the tool at a single point or a progressive friction stir welding performed by advancing the tool in a predetermined direction.
  • the stir welding portion further includes a portion provided with an annular inclined surface that is formed outside the aforementioned space and is inclined so as to approach the current collecting tab layer as the distance from the space increases. It is preferable to provide. In such a stir joint, the thickness of the plastic fluidized metal around the edge of the stir joint surrounding the space can be increased, and burrs can be prevented from occurring at the edge of the stir joint. Can do.
  • a plurality of stirring joints may be formed at predetermined intervals. If comprised in this way, generation
  • the plurality of stirring joints may be formed such that a part of the inclined surface overlaps the inclined surface of another adjacent stirring joint. If comprised in this way, it can prevent more that a burr
  • the stir welding portion may be formed by advancing the stir welding rotary tool in a direction perpendicular to the direction in which the stir welding rotary tool is pushed. In this way, since the stir joint can be formed larger, it is possible to further suppress the occurrence of variations in resistance value.
  • a current collecting tab layer composed of a plurality of current collecting tabs provided on a plurality of electrode plates of the same polarity is formed between a metal pressing plate and a current collector.
  • One or more stir welds by plastically flowing the metal around the stir welding rotary tool by rotating and rotating the stir welding rotary tool from the top of the holding plate toward the current collector while being disposed between And the current collecting tab layer is bonded to the current collector. Then, the indentation depth, the indentation speed, the holding time, and the rotation speed of the rotating tool for stirring joining are determined so that the current collecting tab layer is not exposed on the surface of the stirring joining portion.
  • the indentation depth, indentation speed, holding time and number of rotations of the rotating tool for agitation welding were determined so that the agitation welding part was continuously formed between the holding plate and the current collector by the plastic fluid metal. It is determined so that the temperature of the separator of the plate group does not exceed the shutdown temperature. If it does in this way, it can prevent that a separator melts with the heat generated in the case of friction stir welding.
  • the advancing speed and the rotational speed, the indentation depth, the indentation speed, and the holding time for advancing the agitating welding rotary tool in the direction orthogonal to the pushing direction of the agitating welding rotation tool are set. All the stir joints are formed continuously between the pressing plate and the current collector by the plastic fluid metal, and the temperature of the separator of the electrode plate group is determined not to be higher than the shutdown temperature.
  • the stir welding rotary tool is rotated and moved in a direction perpendicular to the pressing direction in a state where the current collecting tab layer sandwiched between the holding plate and the current collector is cooled.
  • the frictional heat generated by the stir welding may increase. Therefore, cooling the current collecting tab layer sandwiched between the holding plate and the current collector prevents the frictional heat from being transferred to the electrode plate group or cools the heat transferred to the electrode plate group. Therefore, it is possible to prevent the separator formed from a material having low heat resistance from melting. Note that this cooling is not necessary when a separator having high heat resistance is used.
  • FIG. 1 is a partially broken front view of a lithium ion secondary battery 1 as a non-aqueous electrolyte secondary battery to which the first embodiment of the current collecting structure of the secondary battery of the present invention is applied.
  • the thickness dimensions of some components are exaggerated and the number of electrode plates is smaller than the actual number.
  • the lithium ion secondary battery 1 of the present embodiment includes an electrode plate group 3 and a stainless-made square battery case 5 that houses the electrode plate group 3 therein.
  • the battery container 5 includes a battery can 7 having one end opened, and a battery lid 9. After the electrode plate group 3 is inserted into the battery can 7, the opening peripheral edge of the battery can 7, and the battery lid It is sealed by welding the peripheral part of 9.
  • a positive electrode terminal 11 made of aluminum and a negative electrode terminal 13 made of copper are fixed to the battery lid 9.
  • the positive electrode terminal 11 and the negative electrode terminal 13 pass through the cover plate of the battery lid 9 and protrude to the outside of the battery container 5 with screwed terminal portions 11a and 13a, and current collectors 11b and 13b arranged in the battery container. Respectively.
  • a positive terminal nut 21 and a negative terminal nut 23 are screwed onto the screwed terminal portions 11a and 13a.
  • An annular inner packing 15 is provided between the positive electrode terminal 11 and the negative electrode terminal 13 and the battery lid 9.
  • An annular outer packing 17 and a terminal washer 19 are provided on the outer side of the battery lid 9 so as to be opposed to the inner packing 15 via the battery lid 9.
  • the positive electrode terminal 11 and the negative electrode terminal 13 are respectively attached to the battery lid 9 by a positive electrode terminal nut 21 and a negative electrode terminal nut 23 provided at the tip of the screw portion via the inner packing 15, the outer packing 17 and the terminal washer 19. It is fixed.
  • the portion of the battery lid 9 where the positive electrode terminal 11 and the negative electrode terminal 13 are provided ensures a sealed / sealed state in the battery container 5 by the inner packing 15 and the outer packing 17.
  • the battery lid 9 is provided with a gas discharge valve 9a and a liquid injection port 9b welded with stainless steel foil.
  • the gas discharge valve 9a has a function of cleaving the stainless steel foil and releasing the internal gas when the battery internal pressure increases.
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • a non-aqueous electrolyte solution (not shown) in which a lithium salt is dissolved is injected.
  • the positive electrode side pressing plate 25 and the positive electrode current collecting tab layer 27 are attached to the current collector 11 b of the positive electrode terminal 11 by the stirring joint portion 29. Further, the negative electrode side pressing plate 31 and the negative electrode current collecting tab layer 33 are attached to the current collector 13 b of the negative electrode terminal 13 by the stirring joint portion 29.
  • the positive electrode side pressing plate 25 and the positive electrode current collecting tab layer 27 are respectively attached to two surfaces facing in the stacking direction of the electrode plate group 3.
  • the negative electrode side pressing plate 31 and the negative electrode current collection tab layer 33 are attached to the current collector 13 b of the negative electrode terminal 13 on two surfaces facing each other in the stacking direction of the electrode plate group 3.
  • the positive electrode side holding plate 25 is formed in a substantially rectangular parallelepiped shape by an aluminum plate or aluminum alloy plate having a thickness of 1 to 3 mm.
  • aluminum alloys include industrial pure aluminum A1050, A1100, A1200, Al—Cu series A2017, A2024, Al—Mn series A3003, A3004, Al—Si series A4032, Al—Mg series A5005, A5052. , A5083, Al-Mg-Si-based A6061, A6063, Al-Zn-based A7075, etc. (all are JIS).
  • the positive electrode side pressing plate 25 is formed of A5083 or A6063 that can reduce the occurrence of burrs.
  • the positive electrode side holding plate 25 is attached to the current collector 11 b by the stirring joint portion 29 with the positive electrode current collecting tab layer 27 sandwiched between the current collector 11 b of the positive electrode terminal 11.
  • the negative electrode side holding plate 31 is formed in a substantially rectangular parallelepiped shape by a copper plate or a copper alloy plate having a thickness of 1 to 3 mm.
  • the negative electrode side pressing plate 31 is formed of oxygen-free copper C1020, which is a pure copper-based material that can reduce the generation of burrs. Copper or copper alloy is less likely to generate burrs than aluminum or aluminum alloy, and is preferable as a material for the pressing plate.
  • the negative electrode side holding plate 31 is attached to the current collector 13b by the stirring joint portion 29 with the negative electrode current collecting tab layer 33 sandwiched between the current collector 13b of the negative electrode terminal.
  • FIGS. 2 and 3 are perspective views of the lithium ion secondary battery 1 with the battery can 7 removed
  • FIG. 3 is a right side view of the lithium ion secondary battery 1 with the battery can 7 removed.
  • each component is schematically shown for easy understanding. Therefore, each component shown in FIGS. 2 and 3 is different in shape, size, and the like from the actual component of the electrode plate group.
  • the electrode plate group 3 is configured by alternately stacking a plurality of positive electrode plates 35 and a plurality of negative electrode plates 37 via separators 39.
  • the positive electrode plate 35 includes a positive electrode current collector plate 35b having a current collector tab 35a made of aluminum foil, and a positive electrode active material layer (not shown) formed on both surfaces of the positive electrode current collector plate 35b.
  • An aluminum foil having a thickness of 10 to 40 ⁇ m is preferably used. When the aluminum foil is thinner than 10 ⁇ m, it is not preferable because the mechanical strength and the strength against welding are weak and the electric resistance and thermal resistance increase. Moreover, since it will occupy extra space in a battery container when it becomes thicker than 40 micrometers, it is not preferable.
  • the thickness of the aluminum foil of the present embodiment is 20 ⁇ m.
  • the thickness of the positive electrode active material layer is preferably about 30 ⁇ m to 150 ⁇ m.
  • the positive electrode active material layer is prepared by mixing, for example, lithium manganese complex oxide powder, scaly graphite as a conductive material, and polyvinylidene fluoride (PVDF) as a binder at a weight ratio of 85: 10: 5.
  • PVDF polyvinylidene fluoride
  • a slurry obtained by adding and kneading N-methylpyrrolidone (NMP) as a dispersion solvent is applied to the positive electrode current collector plate, and then dried and pressed.
  • a positive electrode current collecting tab 35a made of a mixture-uncoated portion is integrally formed on the side extending along the battery lid 9 of the positive electrode current collector plate.
  • the plurality of positive electrode plates 35 have the same shape.
  • the positive electrode current collecting tab layer 27 is configured by laminating a plurality of positive electrode current collecting tabs 35 a of the plurality of positive electrode plates 35.
  • the positive electrode current collecting tab layer 27 is joined to the current collector 11 b of the positive electrode terminal 11 by the stirring joint portion 29 while being sandwiched between the current collector 11 b of the positive electrode terminal 11 and the positive electrode side holding plate 25. .
  • the plurality of positive electrode current collecting tabs 35 a are divided into two to form two positive electrode current collecting tab layers 27.
  • the negative electrode plate 37 includes a negative electrode current collector plate 37b with a current collecting tab 37a made of electrolytic copper foil, and a negative electrode active material layer (not shown) formed on both surfaces of the negative electrode current collector plate 37b.
  • the thickness of the electrolytic copper foil is preferably 5 to 20 ⁇ m.
  • the thickness of the negative electrode active material layer is preferably 20 ⁇ m to 100 ⁇ m.
  • the negative electrode active material layer includes, for example, 10 parts by mass of polyvinylidene fluoride as a binder with respect to 90 parts by mass of amorphous carbon powder as a negative electrode active material, and a slurry obtained by adding and kneading NMP as a dispersion solvent thereto.
  • a negative electrode current collecting tab 37a formed of a mixture-uncoated portion is integrally formed on a side extending along the battery lid 9 of the negative electrode current collecting plate 37b.
  • the negative electrode current collecting tab 37a is formed so as not to face the positive electrode current collecting tab 35a when the positive electrode plate 35 and the negative electrode plate 37 are laminated.
  • the plurality of negative electrode plates 37 are formed in the same shape.
  • the negative electrode current collecting tab layer 33 is configured by stacking a plurality of negative electrode current collecting tabs 37 a of the plurality of negative electrode plates 37.
  • the negative electrode current collecting tab layer 33 is joined to the current collector 13 b of the negative electrode terminal 13 by the stirring joint portion 29 while being sandwiched between the current collector 13 b of the negative electrode terminal 13 and the negative electrode side holding plate 31. .
  • the plurality of negative electrode current collecting tabs 37 a are divided into two to form two negative electrode current collecting tab layers 33.
  • the separator 39 is formed in a substantially rectangular sheet shape, for example, by a polyethylene porous material through which lithium ions can pass.
  • FIG. 3 only six positive plates, six negative plates, and 12 separators are shown for simplicity of illustration, but this embodiment assuming a capacity of about 100 Ah.
  • the lithium ion secondary battery 1 in practice, several hundred positive plates, several hundred negative plates, and several hundred separators are laminated to form an electrode plate group 3.
  • the current collecting structure on the negative electrode side has the same structure as the current collecting structure on the positive electrode side. Therefore, in FIGS. 3 to 9, reference numerals of the negative-side component members are attached in parentheses, and illustration of the current-collecting structure on the negative-electrode side is omitted.
  • FIG. 4 is a diagram schematically showing a cross section of the stir welding portion 29 on the positive electrode side according to the present embodiment.
  • hatching indicating a cross section is omitted.
  • the stirring joint portion 29 of the present embodiment is formed in a spot shape, and is joined to a joint body portion 41 having a space S extending from the positive electrode side holding plate 25 side to the inside of the current collector 11b of the positive electrode terminal 11, The main body part 41 and the cyclic
  • the joining main body portion 41 is continuous with the cylindrical wall portion 41a extending from the positive electrode side holding plate 25 side toward the current collector 11b of the positive electrode terminal 11, and the end portion of the cylindrical wall portion 41a on the current collector 11b side.
  • a bottom portion 41b having a substantially dome shape that is formed and closes the other end of the cylindrical wall portion 41a.
  • the space S formed inside the cylindrical wall portion 41a is formed so as to have a substantially columnar cross section, and has an opening 41c on the positive electrode side pressing plate 25 side.
  • the joining main body 41 includes a portion 42A made of a plastic fluidized metal of the positive electrode side holding plate 25, a portion 42B made of a plastic fluidized metal obtained by stirring the positive electrode side holding plate 25 and the positive electrode current collecting tab 35a, and the positive electrode side holding plate 25. And a portion 42C made of a plastic fluidized metal obtained by stirring the current collector 11b of the positive current collector tab 35a and the positive electrode terminal 11, and a plastic fluidized metal obtained by stirring the current collector 11b of the positive current collector tab 35a and the positive electrode terminal 11. It is formed by the part 42D which consists of.
  • the joint main body 41 having such a shape has the indentation depth, the indentation speed, the holding time, and the number of revolutions of the stirring welding rotary tool 51 shown in FIG.
  • the positive electrode current collection tab layer 27 is not exposed on the surface exposed in the space S of the bonding main body portion 41 of the present embodiment.
  • the stir welded portion 29 is entirely formed of a continuous plastic fluid metal. Therefore, the resistance value of the joint formed by the joint body 41 is considered to be the lowest. Therefore, according to the present embodiment, since the contact resistance between the current collector of the terminal and the plurality of current collecting tabs can be reduced, the occurrence of variations in resistance value due to friction stir welding can be significantly suppressed.
  • the annular inclined surface portion 43 formed continuously with the joining main body portion 41 is formed by the plastic fluid metal of the positive-side holding plate 25 as a result of using the stirring welding rotating tool 51 having the shape shown in FIG. Has been. Further, when this rotating tool 51 for stir welding is used, an annular convex portion 45 is formed by plastic flow of the positive electrode side pressing plate 25 on the radially outer side of the annular inclined surface portion 43.
  • the inclined surface portion 43 of the present embodiment is formed in an annular shape centering on the opening 41c of the bonding main body portion 41, and approaches the positive electrode current collecting tab layer 27 as the distance from the space S (from the opening 41c) increases. Inclined to.
  • the thickness of the plastic fluidized metal around the inner edge portion of the inclined surface portion 43 is increased, and the plastic fluidized metal flowing to the outer edge portion of the inclined surface portion 43 is reduced. For this reason, the dimension in which the annular convex portion 45 that causes burr formed on the outer edge of the inclined surface portion 43 protrudes from the surface of the positive-side holding plate 25 is small.
  • the annular protrusion 45 is preferably formed so as not to become a burr. Therefore, it is preferable that the shape of the tool used when performing stir welding, the pressing depth of the tool, the pressing speed, the holding time, and the number of rotations are determined so that the annular protrusion 45 does not become a burr.
  • flash can also be cut by post-processing.
  • the negative side stirring joint 29 is also formed in the same manner as the positive side stirring joint 29, and the description thereof will be omitted.
  • the positive electrode current collector tab layer 27 is disposed between the positive electrode side pressing plate 25 and the current collector 11 b of the positive electrode terminal 11.
  • the rotating tool 51 for stirring and welding is pressed from above the positive electrode side holding plate 25 toward the positive electrode terminal 11 while being rotated, so that the positive electrode side holding plate 25 and the positive electrode current collecting tab 35a are pressed. And the part around the rotating tool 51 for stirring and welding of the current collector 11b of the positive electrode terminal 11 is plastically flowed in order.
  • the stir welding rotary tool 51 of the present embodiment includes a columnar portion 53 having a truncated cone shape and an inclined surface forming portion 55.
  • the columnar part 53 has a length extending from the positive electrode pressing plate 25 side to the positive electrode terminal 11.
  • the inclined surface forming portion 55 has a base portion 55a provided integrally with the base portion 53a at one end of the columnar portion 53, and a cross-sectional shape extending in a direction perpendicular to the circumferential direction from the base portion 55a along the columnar portion 53. And an annular portion 55b.
  • As the shapes of the columnar portion 53 and the inclined surface forming portion 55 appropriate shapes can be adopted according to the pressing force and the rotation speed of the rotating tool 51 for stirring and joining.
  • the indentation depth, the indentation speed, the holding time, and the number of rotations of the rotating tool 51 for agitation welding may be such that a continuous agitation junction 29 is formed between the positive-side holding plate 25 and the current collector 11b by a plastic fluid metal.
  • the temperature of the separator 39 of the electrode plate group 3 is set so as not to exceed the shutdown temperature.
  • the rotating tool for stirring and joining rotating at 1000 rpm is pressed from the top of the positive electrode side pressing plate toward the positive electrode terminal with a pressing depth of 4.3 mm, a pressing speed of 100 mm / min, and a holding time of 8 seconds. .
  • the stir welded portion 29 was continuously formed between the positive electrode side pressing plate 25 and the current collector 11b by using a plastic fluid metal.
  • a structure was obtained in which the positive electrode current collecting tab layer 27 was not exposed on the surface of the stir joint 29.
  • it was possible to prevent the separator 39 from being melted by heat generated during friction stir welding.
  • the current collector structure on the negative electrode side can be formed in the same manner. The negative electrode side was pressed for 2 seconds at a rotation speed of 1000 rpm, an indentation depth of 4.7 mm, an indentation speed of 20 mm / min.
  • the stir welding rotary tool 51 of the present embodiment has the inclined surface forming portion 55, the positive side pressing plate softened and plastically fluidized by rotating the rotating stir welding rotary tool 51.
  • the plastic fluidized metal 25 flows toward the base 53a of the columnar portion 53 of the stir welding rotary tool 51 and also on the radially outer side of the inclined surface forming portion 55, as indicated by arrows in FIG. A part flows.
  • the thickness of the plastic fluidized metal around the inner edge portion of the inclined surface portion 43 is increased, and the plastic fluidized metal flowing in the outer edge portion of the inclined surface portion 43 is reduced.
  • the protrusion 45 formed on the outer edge of the inclined surface portion 43 has a small dimension protruding from the surface of the positive electrode side pressing plate 25, thereby suppressing the occurrence of burrs.
  • FIG. 6 is a partially broken front view of the lithium ion secondary battery 101 of the second embodiment to which the secondary battery current collecting structure of the present invention is applied.
  • FIG. 7 is a diagram schematically showing a cross section of the stir welding portion 129 on the positive electrode side.
  • the same members as those in the first embodiment are denoted by reference numerals obtained by adding the number of reference numerals 100 to the reference numerals in FIGS. .
  • the positive electrode side holding plate 125 and the positive electrode current collecting tab layer 127 are connected to the positive electrode terminal by three stirring joint portions 129 formed at a predetermined interval.
  • 111 current collector 111b Such a current collecting structure can be formed by pressing the stir welding rotary tool against the positive-side holding plate 125 at a predetermined interval.
  • FIG. 8 is a diagram schematically showing a cross section of the stirring joint 229 on the positive electrode side of the lithium ion secondary battery of the third embodiment to which the current collecting structure of the secondary battery of the present invention is applied.
  • the same members as those in the embodiment of FIG. 1 are denoted by reference numerals obtained by adding the number of reference numerals 200 to the reference numerals of FIGS. .
  • the positive electrode side holding plate 225 and the positive electrode current collector tab layer 227 are attached to the current collector 211b of the positive electrode terminal by three stirring joints 229.
  • the three stirring joint portions 229 are formed such that a part of the inclined surface portion 243 overlaps with the inclined surface portion 243 of another adjacent stirring joint portion 229. Therefore, a part of the convex portion 245 on the outer edge of the inclined surface portion 243 of the one stir joint portion 229 formed earlier among the adjacent stir joint portions 229 is softened when the adjacent stir joint portion 229 is formed. Therefore, the rate of occurrence of burrs is reduced.
  • FIG. 9 is a diagram schematically showing a cross section of the stir junction 329 on the positive electrode side of the lithium ion secondary battery of the fourth embodiment to which the current collecting structure of the secondary battery of the present invention is applied.
  • members similar to those in the embodiment of FIG. 1 are denoted by reference numerals obtained by adding the number of 300 to the reference numerals appended in FIGS.
  • the stir joint 329 has a shape in which a plastic fluid metal is elongated. Further, a space S is formed at one end of the stir welding portion 329 by pulling out the stir welding rotary tool.
  • the current collecting structure of the present embodiment is formed by moving the stir welding rotary tool in a direction orthogonal to the pressing direction and finally pulling out the stir welding rotary tool.
  • the indentation depth and indentation speed of the rotating tool for agitation welding in the direction orthogonal to the pressing direction and the advancing speed and rotational speed to be advanced in the direction orthogonal to each other are such that the agitation junction is entirely made of plastic fluid metal.
  • the current collecting tab layer is continuously exposed between the holding plate and the current collector, and the temperature of the separator of the electrode plate group is determined not to be higher than the shutdown temperature.
  • the frictional heat is inevitably increased. Therefore, for safety, the current collecting tab layer sandwiched between the holding plate and the current collector is cooled. It is preferable to carry out stir welding. When cooling is used in this manner, even if the frictional heat generated by the stir welding increases, the heat can be prevented from being transmitted to the separator in the electrode plate group and melting the separator. Needless to say, cooling may be used in combination in the first to third embodiments.
  • a separator having high heat resistance is used, it is not necessary to care much about heat generation.
  • the present invention is applied to the current collecting structure of a lithium ion secondary battery, but it is needless to say that the present invention can also be applied to other secondary batteries.
  • the resistance value of the current collecting tab layer which has a large resistance value because a plurality of current collecting tabs are stacked, is partially In addition, there is no additional insertion in series with the resistance value of the stirring joint. Therefore, since the contact resistance between the current collector of the terminal and the plurality of current collecting tabs can be reduced, the occurrence of variation in resistance value due to friction stir welding can be significantly suppressed.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Connection Of Batteries Or Terminals (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)

Abstract

La présente invention se rapporte à une structure de collecteur de batterie rechargeable qui présente une faible résistance électrique, et se rapporte également à un procédé permettant de former la structure de collecteur de batterie rechargeable. Une partie de soudage par malaxage est formée par soudage par friction-malaxage de telle sorte qu'une couche de languette de collecteur d'électrode positive (27) ne soit pas exposée à la surface. Dans la partie de soudage par malaxage, un collecteur (11b) d'une borne d'électrode positive (11), la couche de languette de collecteur d'électrode positive (27) et une plaque de pressage d'électrode positive (25) sont soudés ensemble.
PCT/JP2014/059960 2013-04-04 2014-04-04 Structure de collecteur de batterie rechargeable et procédé permettant de former une structure de collecteur de batterie rechargeable WO2014163184A1 (fr)

Priority Applications (1)

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JP2013078256 2013-04-04

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Publication number Priority date Publication date Assignee Title
KR20170055439A (ko) * 2015-11-11 2017-05-19 주식회사 엘지화학 파우치형 이차전지 및 그의 제조방법
KR20180061681A (ko) * 2016-11-30 2018-06-08 주식회사 엘지화학 이중 용접 구조를 가진 전지셀

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JP2005011675A (ja) * 2003-06-19 2005-01-13 Shin Kobe Electric Mach Co Ltd 密閉型電池
JP2005118877A (ja) * 2003-09-26 2005-05-12 Nippon Chemicon Corp 摩擦撹拌溶接方法および該摩擦撹拌溶接方法を用いた接続構造
JP2007273193A (ja) * 2006-03-30 2007-10-18 Nippon Chemicon Corp 電気化学デバイス

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JP2003126972A (ja) * 2001-10-19 2003-05-08 Hitachi Ltd 摩擦攪拌接合方法

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JP2005011675A (ja) * 2003-06-19 2005-01-13 Shin Kobe Electric Mach Co Ltd 密閉型電池
JP2005118877A (ja) * 2003-09-26 2005-05-12 Nippon Chemicon Corp 摩擦撹拌溶接方法および該摩擦撹拌溶接方法を用いた接続構造
JP2007273193A (ja) * 2006-03-30 2007-10-18 Nippon Chemicon Corp 電気化学デバイス

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170055439A (ko) * 2015-11-11 2017-05-19 주식회사 엘지화학 파우치형 이차전지 및 그의 제조방법
KR20180061681A (ko) * 2016-11-30 2018-06-08 주식회사 엘지화학 이중 용접 구조를 가진 전지셀
EP3396738A4 (fr) * 2016-11-30 2019-06-05 LG Chem, Ltd. Cellule de batterie à double structure de soudage
KR102032773B1 (ko) 2016-11-30 2019-10-16 주식회사 엘지화학 이중 용접 구조를 가진 전지셀
US11276905B2 (en) 2016-11-30 2022-03-15 Lg Energy Solution, Ltd. Battery cell having dual welding structures

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