WO2021246177A1 - Film d'étanchéité ainsi que conducteur à languette et batterie secondaire l'utilisant - Google Patents

Film d'étanchéité ainsi que conducteur à languette et batterie secondaire l'utilisant Download PDF

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Publication number
WO2021246177A1
WO2021246177A1 PCT/JP2021/018980 JP2021018980W WO2021246177A1 WO 2021246177 A1 WO2021246177 A1 WO 2021246177A1 JP 2021018980 W JP2021018980 W JP 2021018980W WO 2021246177 A1 WO2021246177 A1 WO 2021246177A1
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Prior art keywords
polypropylene
sealing film
layer
mfr
contained
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PCT/JP2021/018980
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English (en)
Japanese (ja)
Inventor
庸碩 成
元秀 武市
毅 矢野
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株式会社ケムソル
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Priority claimed from PCT/JP2020/022093 external-priority patent/WO2021100226A1/fr
Application filed by 株式会社ケムソル filed Critical 株式会社ケムソル
Priority to CN202180039809.3A priority Critical patent/CN115668604A/zh
Publication of WO2021246177A1 publication Critical patent/WO2021246177A1/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
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/186—Sealing members characterised by the disposition of the sealing members
    • H01M50/188—Sealing members characterised by the disposition of the sealing members the sealing members being arranged between the lid and terminal
    • 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
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/105—Pouches or flexible bags
    • 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
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/195—Composite material consisting of a mixture of organic and inorganic materials
    • 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
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/197—Sealing members characterised by the material having a layered structure
    • 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
    • H01M50/183—Sealing members
    • H01M50/19—Sealing members characterised by the material
    • H01M50/198—Sealing members characterised by the material characterised by physical properties, e.g. adhesiveness or hardness
    • 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
    • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
    • H01M50/124—Primary casings; Jackets or wrappings characterised by the material having a layered structure
    • 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 sealing film that is placed between a lead conductor connected to a positive electrode or a negative electrode and the exterior package and heat-sealed in a secondary battery covered with an exterior package. Further, the present invention relates to a tab lead using the sealing film. Further, the present invention relates to a secondary battery using the sealing film.
  • Patent Document 1 describes a laminated metal terminal-coated resin film for a secondary battery that covers a metal terminal connected to a positive or negative electrode of a secondary battery, wherein the resin film has a three-layer structure.
  • the melt flow rate of at least one resin constituting the resin film is set to 0.1 to 2.5 g / 10 min, and the core layer and the skin are used.
  • a resin film coated with a metal terminal for a secondary battery in which the difference in melt flow rate from the layer is 5 to 30 g / 10 min is described.
  • Patent Document 2 is a sealant for tab leads that seals the tab leads of a laminated lithium ion secondary battery, and has a three-layer structure including a co-extruded laminate adhesive layer, an insulating layer, and a lead conductor adhesive layer.
  • the laminated adhesive layer is made of a polypropylene resin having a melting point of 140 ° C. or lower and a deflection temperature under load of 70 ° C. or higher
  • the insulating layer is made of a polypropylene resin having a melting point of 145 ° C. or higher and a deflection temperature under load of 100 ° C. or higher.
  • a sealing material for tab leads which is made of a polymer alloy of acid-modified polypropylene having a melting point of 140 ° C. or lower and a polypropylene-based resin, is described. According to this, it is said that the difference in melting point between the insulating layer and the laminated layer can be increased to prevent the insulating layer from melting and flowing out in the heat sealing process, and as a result, the occurrence of a short circuit can be prevented. Further, it is said that by setting the deflection temperature under load of the insulating layer to 100 ° C. or higher, the amount of deformation due to pressurization at the time of heat welding at the time of battery sealing can be reduced, and the occurrence of a short circuit can also be prevented.
  • the present invention has been made to solve the above problems, and by sandwiching a sealing film between the lead conductor and the outer package and heat-sealing, the metal layer in the outer package and the lead conductor are separated from each other.
  • a sealing film used for such a secondary battery and a tab lead using the same.
  • the subject is a sealing film that is placed between a lead conductor connected to a positive or negative electrode and the outer package and heat-sealed in a secondary battery covered with an outer package; the sealing film.
  • the core layer has a melting point of 155 to 166 ° C. and a melt flow rate (MFR) of 0.5 to 5 g.
  • the skin layer contains polypropylene having a melting point of 120 to 150 ° C. and a melt flow rate (MFR) of 1 to 40 g / 10 min, and the core layer has a charpy strength at 23 ° C.
  • the sealing is 15 kJ / m 2 or more, the thickness of the sealing film is 30 to 300 ⁇ m, and the ratio of the thickness of the skin layer to the thickness of the core layer is 0.2 to 5. It is solved by providing a film.
  • the core layer contains polypropylene having a melting point of 158 to 166 ° C. and a melt flow rate (MFR) of 1 to 3 g / 10 min, and the skin layer has a melting point of 128 to 150 ° C. It preferably contains polypropylene having a melt flow rate (MFR) of 1-7 g / 10 min.
  • the polypropylene contained in at least one of the skin layers is modified with an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride or an unsaturated epoxy compound. It is also preferable that the polypropylene contained in the core layer is a polypropylene block copolymer.
  • one layer of the skin layer is a metal adhesive layer that adheres to the lead conductor
  • the other layer is a package adhesive layer that adheres to the exterior package
  • the epoxy contained in the metal adhesive layer is Polypropylene modified with unsaturated carboxylic acid, unsaturated carboxylic acid anhydride or unsaturated epoxy compound
  • the polypropylene contained in the package adhesive layer is unsaturated carboxylic acid, unsaturated carboxylic acid anhydride or unsaturated epoxy. It is also preferable that it is a compound-modified polypropylene or a polypropylene random copolymer.
  • the melting point of polypropylene contained in the package adhesive layer is higher than the melting point of polypropylene contained in the metal adhesive layer. It is also preferable that the polypropylene MFR contained in the metal adhesive layer is higher than either the polypropylene MFR contained in the core layer or the polypropylene MFR contained in the package adhesive layer.
  • the above-mentioned problems include a power generation element including a positive electrode, a negative electrode, an electrolyte and a separator, an exterior package accommodating the power generation element and having a heat-sealed peripheral portion, and the exterior package connected to the positive electrode or the negative electrode.
  • a secondary battery having a lead conductor drawn out and a sealing film disposed between the exterior package and the lead conductor and formed by heat sealing; the exterior package is at least a metal layer and a sealant resin. It is also solved by providing a secondary battery comprising a multilayer film including a layer and characterized in that the sealing film is the above-mentioned sealing film.
  • the sealing film of the present invention is excellent in insulating property and sealing property. Therefore, by sandwiching such a sealing film between the lead conductor of the secondary battery and the outer package and heat-sealing it, it is possible to prevent a short circuit between the metal layer and the lead conductor in the outer package. , It is possible to prevent the seal portion from being destroyed and leaking when the pressure inside the battery rises.
  • This provides a secondary battery having excellent insulation and sealing properties, and a tab lead used in the manufacture thereof. In particular, even when the size of the secondary battery is increased, sufficient insulation and sealing properties can be exhibited.
  • FIG. 2 is a cross-sectional view taken along the line XY in FIG. It is a figure which showed the measuring method of the spread ratio of the sealing film before and after a heat seal. It is a figure which showed the measuring method of the adhesive strength.
  • the present invention relates to a sealing film that is placed between a lead conductor connected to a positive electrode or a negative electrode and the exterior package in a secondary battery covered with an exterior package and is heat-sealed.
  • the sealing film 20 of the present invention is a three-layered multilayer sealing film in which a core layer 21 and skin layers 22 and 23 are formed on both sides thereof.
  • FIG. 2 shows the appearance of the secondary battery 10 of the present invention using the sealing film 20.
  • FIG. 3 shows a cross-sectional view of a heat-sealed portion of the secondary battery 10 of the present invention.
  • the secondary battery 10 of the present invention is connected to a power generation element including a positive electrode, a negative electrode, an electrolyte and a separator, an exterior package 40 accommodating the power generation element and having a peripheral portion heat-sealed, and the positive electrode or the negative electrode. It has a lead conductor 31 drawn out to the outside of the outer package 40, and a sealing film 20 arranged between the outer package 40 and the lead conductor 31 and heat-sealed.
  • the exterior package 40 at this time is composed of a multilayer film including a metal layer 42 for preventing the permeation of oxygen and moisture and a sealant resin layer 41 for heat sealing, and may be sealed in a pouch shape. many.
  • the sealing film 20 of the present invention is adopted in order to prevent a short circuit between the lead conductor 31 and the metal layer 42 in the exterior package 40 and to improve the sealing property between the lead conductor 31 and the exterior package 40. ..
  • the sealing film is required to have a higher degree of insulation.
  • the sealing film has a three-layer structure of polypropylene, and the melting point of polypropylene in the core layer is higher than that in polypropylene in the skin layer. Measures to increase the melt viscosity and the deflection temperature under load have been proposed. As a result, the skin layer can be easily melted and flowed to enable thermal adhesion, while the core layer can withstand the pressure from above and below and maintain a sufficient thickness, and the insulating property is ensured.
  • the pressure inside the secondary battery may rise if the temperature rises, the electrolyte decomposes and vaporizes, or an external force is applied.
  • the present inventors have a problem that when the internal pressure of the secondary battery becomes extremely high, if the sealing film having a three-layer structure of polypropylene is used, the sealing film is destroyed and the electrolytic solution leaks out. I noticed that there are cases. Then, in order to clarify the cause, the cross-sectional shape of the adhesive portion of the sealing film was observed.
  • FIG. 4 shows a sectional view taken along line XY of FIG. 2 in the secondary battery having the configuration described in Comparative Example 1 of the present application.
  • the left side is the heat seal portion and the right side is the inside of the battery.
  • the metal layer 42 in the exterior package 40 and the lead conductor 31 come close to each other, and the thickness of the sealant resin layer 41, the skin layers 22, and 23 is greatly reduced, but the core layer 21 is sufficiently thick.
  • the sealing film of the present invention thus found is a three-layered multilayer sealing film in which a core layer and skin layers are formed on both sides thereof.
  • the core layer contains polypropylene having a melting point of 155 to 166 ° C. and a melt flow rate (MFR) of 0.5 to 5 g / 10 min.
  • the skin layer comprises polypropylene having a melting point of 120-150 ° C. and a melt flow rate (MFR) of 1-40 g / 10 min.
  • the Charpy strength of the core layer at 23 ° C. is 15 kJ / m 2 or more.
  • the sealing film has a thickness of 30 to 300 ⁇ m, and the ratio of the thickness of the skin layer to the thickness of the core layer is 0.2 to 5.
  • polypropylene used here includes polypropylene homopolymers (H-PP), polypropylene random copolymers (R-PP) and polypropylene block copolymers (B-PP), which are commercially available from polypropylene manufacturers.
  • Polypropylene homopolymer is obtained by polymerizing only propylene monomer, has a high melting point, and has a high elastic modulus.
  • the polypropylene random copolymer is a random copolymerization of propylene with a small amount of other comonomer, and the comonomer is randomly incorporated into the polypropylene chain.
  • Random copolymers have lower melting points and modulus of elasticity than homopolymers.
  • Polypropylene block copolymers have a structure in which a chain of polypropylene homopolymers and a chain of polymers of a small amount of other comonomer are linked. Block copolymers have improved impact resistance while exhibiting melting points and elastic moduli close to homopolymers.
  • Polypropylene homopolymers, polypropylene random copolymers, and polypropylene block copolymers are commercially available, and although their chemical compositions are not specified, their melting points, melt flow rates, elastic moduli, and charpy strength are shown in the catalog. It can be appropriately selected and used.
  • the greatest feature of the sealing film 20 of the present invention is that the core layer 21 contains polypropylene having a melting point of 155 to 166 ° C. and a melt flow rate (MFR) of 0.5 to 5 g / 10 min, and the core layer 21.
  • the Charpy intensity at 23 ° C. is 15 kJ / m 2 or more.
  • the melting point of polypropylene contained in the core layer 21 is 155 to 166 ° C. If the melting point is less than 155 ° C., the difference in melting point from polypropylene contained in the skin layers 22 and 23 becomes small, which is not preferable.
  • the heat sealing step the skin layers 22 and 23 are melted, and the skin layers 22 and 23 are heat-sealed with the lead conductor 31 and the exterior package 40.
  • the core layer 21 is less likely to flow than the skin layers 22 and 23 even when heated and pressurized in the heat sealing step. Therefore, a certain thickness can be secured as the core layer 21, and excellent insulating properties can be obtained.
  • the melting point is preferably 158 ° C. or higher, more preferably 161 ° C. or higher, and even more preferably 163 ° C. or higher. On the other hand, the melting point is preferably 165 ° C. or lower.
  • the melting point in the present specification means a melting peak temperature (° C.) measured at a heating rate of 10 ° C./min at the time of measuring 2nd Run using a differential scanning calorimeter (DSC).
  • DSC differential scanning calorimeter
  • the MFR of polypropylene contained in the core layer 21 is 0.5 to 5 g / 10 min. If the MFR is less than 0.5 g / 10 min, the viscosity becomes too high and the sealing film 20 cannot be stably formed.
  • the MFR is preferably 1 g / 10 min or more, more preferably 1.2 g / 10 min or more, and even more preferably 1.5 g / 10 min or more.
  • the MFR exceeds 5 g / 10 min, the fluidity of polypropylene becomes too high in the heat sealing step, the thickness of the core layer 21 in the sealing portion becomes thin, and excellent insulating properties cannot be obtained.
  • the MFR is preferably 3 g / 10 min or less, more preferably 2.8 g / 10 min or less, further preferably 2.5 g / 10 min or less, and particularly preferably 2.0 g / 10 min or less. preferable.
  • the MFR in the present specification is a value measured at 230 ° C. under a load of 2.16 kg in accordance with JIS K7210.
  • the Charpy strength of the core layer 21 at 23 ° C. is 15 kJ / m 2 or more.
  • Charpy strength is 20 kJ / m 2 or more, more preferably 40 kJ / m 2 or more, further preferably 60 kJ / m 2 or more.
  • the Charpy strength is usually 200 kJ / m 2 or less.
  • the Charpy intensity in the present specification is a value measured at 23 ° C. according to the 1eA method (notched) of JIS K7111-1.
  • the polypropylene contained in the core layer 21 is preferably a polypropylene block copolymer. Since the polypropylene contained in the core layer 21 is a polypropylene block copolymer, it is possible to effectively prevent the sealing film 20 from being destroyed starting from the weak point of the core layer 21.
  • polypropylene block copolymers are known to have a relatively high melting point and elastic modulus and high Charpy strength, and are often used for injection-molded products that require impact resistance. On the other hand, it is rarely used for flexible films because the extrudability is not always good. Moreover, only some of the grades have a Charpy strength of 15 kJ / m 2 or more at 23 ° C.
  • the skin layers 22 and 23 contain polypropylene having a melting point of 120 to 150 ° C. and a melt flow rate (MFR) of 1 to 40 g / 10 min.
  • the melting point of polypropylene contained in the skin layers 22 and 23 is 120 to 150 ° C. When the melting point is less than 120 ° C., the heat resistance to heat generation and external heat during use of the secondary battery 10 is lowered.
  • the melting point is preferably 128 ° C. or higher, more preferably 130 ° C. or higher, and even more preferably 135 ° C. or higher.
  • the melting point exceeds 150 ° C., the difference in melting point from polypropylene contained in the core layer 21 becomes small, so that the core layer 21 also tends to melt in the heat sealing step, and excellent insulating properties cannot be obtained.
  • the melting point is preferably 148 ° C. or lower, more preferably 146 ° C. or lower.
  • the MFR of polypropylene contained in the skin layers 22 and 23 is 1 to 40 g / 10 min. If the MFR is less than 1 g / 10 min, the viscosity becomes too high and the sealing film 20 cannot be stably formed.
  • the MFR is preferably 1.5 g / 10 min or more, and more preferably 2 g / 10 min or more.
  • the MFR exceeds 40 g / 10 min, the difference from the polypropylene MFR contained in the core layer 21 becomes large, and in this case as well, the sealing film 20 cannot be stably formed, and the skin layer 22 and the skin layer 22 The mechanical strength of 23 is also reduced.
  • the MFR is preferably 7 g / 10 min or less, more preferably 6.5 g / 10 min or less, and even more preferably 6 g / 10 min or less.
  • the ratio of the polypropylene MFR s contained in the skin layers 22 and 23 (MFR s / MFR c ) to the polypropylene MFR c contained in the core layer 21 is 0.8 to 7. Is preferable.
  • the ratio (MFR s / MFR c ) is less than 0.8, the fluidity of polypropylene in the core layer 21 becomes too high in the heat sealing step, the thickness of the obtained core layer 21 becomes thin, and the insulating property deteriorates. There is a risk.
  • the ratio (MFR s / MFR c ) is more preferably 1 or more, and even more preferably 1.5 or more.
  • the ratio (MFR s / MFR c ) exceeds 7, the viscosities of the skin layers 22 and 23 become too low, and the sealing film 20 may not be stably formed.
  • the ratio (MFR s / MFR c ) is more preferably 6 or less, and even more preferably 4 or less.
  • the polypropylene contained in at least one of the skin layers 22 and 23 is modified with an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride or an unsaturated epoxy compound. These modifications may be due to random copolymerization or block copolymerization, or may be graft modification.
  • one of the skin layers 22 and 23 is the metal adhesive layer 22 that adheres to the lead conductor 31, and the other layer is the package adhesive layer 23 that adheres to the exterior package 40.
  • the polypropylene contained in the metal adhesive layer 22 is preferably polypropylene modified with an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride or an unsaturated epoxy compound. By doing so, the adhesion with the lead conductor 31 can be improved. Above all, polypropylene is more preferably polypropylene modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride.
  • the polypropylene contained in the metal adhesive layer 22 and the polypropylene contained in the package adhesive layer 23 may be the same type of polypropylene or different types of polypropylene.
  • the metal adhesive layer 22 and the package adhesive layer 23 are no longer distinguished in the sealing film 20, so that it is not necessary to identify the front and back surfaces when performing the sealing work, and workability is improved. It is also possible to prevent the occurrence of defective products due to incorrect front and back surfaces.
  • the polypropylene contained in the metal adhesive layer 22 is modified with an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride or an unsaturated epoxy compound. It is preferable that the polypropylene is polypropylene and the polypropylene contained in the package adhesive layer 23 is a polypropylene random copolymer which is not so modified. By doing so, it is possible to secure the adhesion with the lead conductor 21 while suppressing the manufacturing cost of the sealing film 20.
  • the melting point of polypropylene contained in the package adhesive layer 23 is higher than the melting point of polypropylene contained in the metal adhesive layer 22.
  • the heat sealing step heat is applied from the outer package 40 side, but the heat is first generated by making the melting point of polypropylene contained in the package adhesive layer 23 higher than the melting point of polypropylene contained in the metal adhesive layer 22. It is possible to prevent the polypropylene contained in the added package adhesive layer 23 from excessively flowing and spreading.
  • the difference between the melting point of polypropylene contained in the package adhesive layer 23 and the melting point of polypropylene contained in the metal adhesive layer 22 is preferably 2 ° C. or higher.
  • the polypropylene MFR contained in the metal adhesive layer 22 is higher than either the polypropylene MFR contained in the core layer 21 or the polypropylene MFR contained in the package adhesive layer 23. By doing so, the polypropylene contained in the metal adhesive layer 22 can be wrapped around the lead conductor 31 without a gap.
  • the difference between the polypropylene MFR contained in the metal adhesive layer 22 and the polypropylene MFR contained in the core layer 21 and the polypropylene MFR contained in the package adhesive layer 23 is preferably 1 or more.
  • the core layer 21 or the skin layers 22 and 23 of the sealing film 20 of the present invention both contain polypropylene.
  • the polypropylene content of each layer is usually 50% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more.
  • various additives that can be normally used such as fillers and colorants, may be contained.
  • a resin other than polypropylene may be contained, but in that case, the content of the other resin is usually 20% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass. % Or less, preferably not substantially contained.
  • the thickness of the sealing film 20 is 30 to 300 ⁇ m. If the thickness of the sealing film 20 is less than 30 ⁇ m, it is not possible to sufficiently prevent a short circuit between the lead conductor 31 and the metal layer 42 in the exterior package 40.
  • the thickness of the sealing film 20 is preferably 50 ⁇ m or more, more preferably 70 ⁇ m or more. On the other hand, if the thickness of the sealing film 20 exceeds 300 ⁇ m, the weight increases and the cost also increases.
  • the thickness of the sealing film 20 is preferably 250 ⁇ m or less, more preferably 200 ⁇ m or less, and even more preferably 150 ⁇ m or less.
  • the ratio of the thicknesses of the skin layers 22 and 23 to the thickness of the core layer 21 is 0.2 to 5. When the ratio is less than 0.2, the adhesion of the sealing film 20 to the lead conductor 31 and the outer package 40 is lowered.
  • the ratio is preferably 0.3 or more, and more preferably 0.5 or more. On the other hand, when the ratio exceeds 5, excellent insulating properties cannot be obtained.
  • the ratio is preferably 4 or less, more preferably 3 or less.
  • the thicknesses of the skin layers 22 and 23 referred to here are the thicknesses of the metal adhesive layer 22 and the package adhesive layer 23, respectively.
  • the lead conductor 31 used in the secondary battery of the present invention is a metal tape-shaped member connected to a positive electrode or a negative electrode, and can be charged and discharged through the lead conductor 31.
  • Aluminum is mainly used as the lead conductor 31 connected to the positive electrode.
  • nickel or copper plated with nickel, or a clad material of copper and nickel is mainly used.
  • the thickness of the lead conductor 31 is usually 0.05 to 1 mm, and the width is 2 to 100 mm.
  • the tab lead 30 used in the secondary battery 10 of the present invention is formed by covering both sides of a part of the lead conductor 31 with a sealing film 20. Since the sealing film 20 is heat-sealed to the lead conductor 31 in advance, the space between the lead conductor 31 and the sealing film 20 can be reliably sealed, and the positioning when the outer package 40 is heat-sealed can be determined. It will be easier. Since one end of the lead conductor 31 is connected to the positive electrode or the negative electrode and the other end is connected to the charging / discharging device, the intermediate portion thereof is covered with the sealing film 20. Then, the outer package 40 is heat-sealed at a position where it overlaps with the sealing film 20.
  • the exterior package 40 used in the secondary battery 10 of the present invention is made of a multilayer film including at least a metal layer 42 and a sealant resin layer 41.
  • the surface resin layer 43 may be appropriately printed or the like, or the surface resin layer 43 may be composed of a plurality of resin layers.
  • the total thickness of the outer package 40 is usually 50 to 500 ⁇ m.
  • the resin constituting the sealant resin layer 41 may be any resin that can be heat-sealed, and a thermoplastic resin is usually used. Preferably, polyolefin, especially polypropylene, is preferably used.
  • the thickness of the sealant resin layer 41 is usually 30 to 200 ⁇ m.
  • the resin constituting the surface resin layer 43 is not particularly limited, and a polyamide resin, a polyester resin, a polyolefin resin, a polystyrene resin, a thermoplastic polyimide resin, a phenoxy resin, an epoxy resin, an acetal resin, a fluororesin, or the like can be used depending on the application. Can be used.
  • the thickness of the surface resin layer 43 is usually 30 to 400 ⁇ m.
  • the metal constituting the metal layer 42 is not particularly limited, but aluminum is preferable in consideration of workability, flexibility, cost, and the like.
  • a metal foil having a thickness of 5 to 100 ⁇ m may be used, or a thin-film film having a thickness of 0.1 to 2 ⁇ m may be used.
  • the power generation element including the positive electrode, the negative electrode, the electrolyte and the separator is housed and sealed by heat-sealing the peripheral portion of the outer package.
  • the type of the secondary battery 10 is not limited, but a lithium ion battery is suitable.
  • a so-called pouch-shaped package in which two exterior packages 40 face each other to accommodate a power generation element is preferable.
  • the sealing film 20 is arranged vertically at a predetermined position of the lead conductor 31 and the fused portion is heated and pressed from above and below. At this time, by not only heating from above and below but also heating the lead conductor 31 at the same time, excessive flow of the sealing film 20 is suppressed, and it is easy to fuse with a width substantially the same as the width of the sealing film 20. Become. Further, by arranging a cushioning material such as silicone rubber or a Teflon sheet between the press head and the lead conductor 31 at the time of pressurization, it is possible to improve the wraparound of the resin to the end of the lead conductor 31.
  • a cushioning material such as silicone rubber or a Teflon sheet
  • the exterior package 40 containing the power generation element is superposed on the portion of the tab lead 30 thus obtained covered with the sealing film 20, and the peripheral edge of the exterior package 40 is heated and pressed from both sides to heat and pressurize the secondary battery 10. To manufacture.
  • the lead conductor 31 and the sealing film 20 can be overlapped and heat-sealed at the same time.
  • the secondary battery 10 of the present invention thus obtained is a secondary battery 10 that can prevent a short circuit between the metal layer 42 and the lead conductor 31 in the outer package 40 and has excellent sealing properties and insulating properties. It can be used particularly usefully in a large secondary battery or the like, which requires a high degree of reliability as the heat sealing conditions of the outer package 40 become strict.
  • Example 1 [Preparation of sealing film] A three-layer coextruded film manufacturing apparatus equipped with three extruders was used to manufacture the sealing film 20.
  • Polypropylene random copolymer pellets (R-PP) were put into one of the outer layer (for package adhesive layer 23) extruders, and acid-modified propylene random copolymer pellets (R-PP) were put into the other outer layer (metal adhesive layer 22) extruder.
  • A-PP) was introduced.
  • polypropylene block copolymer pellets (B-PP) were put into the extruder for the core layer 21.
  • Coextrusion molding was performed by setting the extrusion temperature of the three extruders to 200 ° C.
  • FIG. 5A An aluminum plate (A1050) having a thickness of 0.1 mm was slitted to prepare a lead conductor 31 having a length of 13 mm and a width of 4 mm. As shown in FIG. 5A, the lead conductor 31 was sandwiched between two sealing films 20, and the upper and lower portions thereof were sandwiched between 0.2 mm-thick silicone rubber sheets. At this time, the length A of the sealing film 20 was measured.
  • the exterior packaging material As the exterior packaging material, a multilayer film laminated in the order of the polyamide layer 25 ⁇ m / aluminum foil 50 ⁇ m / polypropylene layer 25 ⁇ m from the outermost layer was used. This was cut into strips having a length of 100 mm and a width of 20 mm, and brought into contact with both sides of the sealing film 20 portion of the produced tab lead 30 (contact area: 3 mm ⁇ 8 mm). At this time, the two exterior package materials were arranged so that the polypropylene layer of the exterior package material was in contact with the sealing film 20. Subsequently, a sample was obtained by heating and pressurizing at a temperature of 180 ° C.
  • Examples 2 to 6, Comparative Examples 1 to 4 As shown in Tables 1 and 2, a sealing film 20 was prepared and evaluated in the same manner as in Example 1 except that the types of polypropylene forming the package adhesive layer 23, the core layer 21 and the metal adhesive layer 22 were changed. ..
  • Table 1 two melting peaks (134 ° C. and 104 ° C.) of polypropylene contained in the package adhesive layer 23 of Example 5 were observed. Since the peak height at 134 ° C. was higher than the peak height at 104 ° C., 134 ° C. was set as the melting point of polypropylene contained in the package adhesive layer 23.
  • Tables 1 and 2 Here, when the fractured portion in the tensile test was agglutination fracture of the sealing film 20, the evaluation result was B.
  • Rechargeable battery 20 Encapsulating film 21 Core layer 22 Skin layer (metal adhesive layer) 23 Skin layer (package adhesive layer) 30 Tab lead 31 Lead conductor 40 Exterior package 41 Sealant resin layer 42 Metal layer 43 Surface resin layer 5 Protrusion 6 Notch

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
  • Laminated Bodies (AREA)

Abstract

La présente invention concerne un film d'étanchéité conçu pour le thermoscellage entre un boîtier externe et un conducteur de fil qui est connecté à une électrode positive ou négative dans une batterie secondaire recouverte du boîtier externe, le film d'étanchéité étant caractérisé en ce qu'il s'agit d'un film d'étanchéité multicouche à trois couches constitué d'une couche centrale et de couches de peau sur les deux surfaces de la couche centrale et en ce que : la couche centrale contient un polypropylène qui a un point de fusion de 155 à 166 °C et un indice de fluidité à l'état fondu (MFR) de 0,5 à 5 g/10 min; les couches de peau contiennent un polypropylène qui a un point de fusion de 120 à 150 °C et un indice de fluidité à l'état fondu (MFR) de 1 à 40 g/10 min; la résistance à l'impact Charpy de la couche centrale est supérieure ou égale à 15 kJ/m2 à 23°C; l'épaisseur du film d'étanchéité est de 30 à 300 µm; et le rapport de l'épaisseur des couches de peau à l'épaisseur de la couche centrale est de 0,2 à 5. Ce film d'étanchéité est utilisé pour fabriquer une batterie secondaire qui présente d'excellentes propriétés d'isolation et une excellente performance d'étanchéité.
PCT/JP2021/018980 2019-11-22 2021-05-19 Film d'étanchéité ainsi que conducteur à languette et batterie secondaire l'utilisant WO2021246177A1 (fr)

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JPPCT/JP2020/022093 2020-06-04
PCT/JP2020/022093 WO2021100226A1 (fr) 2019-11-22 2020-06-04 Film d'étanchéité ainsi que conducteur à languette et batterie secondaire l'utilisant

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PCT/JP2020/003530 WO2021100213A1 (fr) 2019-11-22 2020-01-30 Film de scellement, fil de patte et batterie secondaire les utilisant
PCT/JP2021/018980 WO2021246177A1 (fr) 2019-11-22 2021-05-19 Film d'étanchéité ainsi que conducteur à languette et batterie secondaire l'utilisant

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US11973197B2 (en) 2021-12-27 2024-04-30 Sumitomo Electric Industries, Ltd. Lead wire for nonaqueous electrolyte battery, insulating film and nonaqueous electrolyte battery

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WO2021246472A1 (fr) * 2020-06-03 2021-12-09 藤森工業株式会社 Film d'étanchéité, élément de fil conducteur d'électrode et batterie
CN114497910B (zh) * 2022-01-10 2024-05-17 珠海冠宇电池股份有限公司 一种极耳及包括所述极耳的电池

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JP2014019981A (ja) * 2012-07-19 2014-02-03 Diatex Co Ltd フラットヤーンの製造方法及びクロス積層体の製造方法
JP2014229505A (ja) * 2013-05-23 2014-12-08 日立マクセル株式会社 薄型電池用封止材
JP2016091939A (ja) * 2014-11-10 2016-05-23 凸版印刷株式会社 端子用樹脂フィルム、それを用いたタブ及び蓄電デバイス

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JP2014225378A (ja) * 2013-05-16 2014-12-04 株式会社日立製作所 タブリード用シール材、タブリードおよびリチウムイオン二次電池
JP6699105B2 (ja) * 2015-08-04 2020-05-27 凸版印刷株式会社 端子用樹脂フィルム、それを用いたタブ及び蓄電デバイス
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JP2014019981A (ja) * 2012-07-19 2014-02-03 Diatex Co Ltd フラットヤーンの製造方法及びクロス積層体の製造方法
JP2014229505A (ja) * 2013-05-23 2014-12-08 日立マクセル株式会社 薄型電池用封止材
JP2016091939A (ja) * 2014-11-10 2016-05-23 凸版印刷株式会社 端子用樹脂フィルム、それを用いたタブ及び蓄電デバイス

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11973197B2 (en) 2021-12-27 2024-04-30 Sumitomo Electric Industries, Ltd. Lead wire for nonaqueous electrolyte battery, insulating film and nonaqueous electrolyte battery

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