JP6987175B2 - Electrode lead wire member for non-aqueous batteries - Google Patents

Description

The present invention relates to an electrode lead wire member for a non-aqueous battery in which an organic electrolyte is used as an electrolytic solution such as a lithium ion battery as a secondary battery or an electric double layer capacitor (hereinafter referred to as a capacitor).

In recent years, with the rise of global environmental problems, the spread of electric vehicles and the effective utilization of natural energy such as wind power generation and solar power generation have become issues. Along with this, in these technical fields, secondary batteries such as lithium ion batteries and capacitors are attracting attention as storage batteries for storing electric energy. In addition, the outer container for storing the lithium-ion battery used in electric vehicles, etc. can be a flat bag made by using a battery exterior laminate in which an aluminum foil and a resin film are laminated, or by drawing or overhanging. A molded container is used to make it thinner and lighter.
By the way, the electrolytic solution of a lithium ion battery has a property of being vulnerable to moisture and light. Therefore, as the exterior material for a lithium-ion battery, a battery exterior laminate having excellent waterproof and light-shielding properties, in which a base material layer made of polyamide or polyester and an aluminum foil are laminated, is used.

In order to store a lithium ion battery in a storage container created by using such a battery exterior laminate, for example, as shown in FIG. 3A, the battery exterior laminate is used in advance to form a recess. A tray-shaped shape having 31 is formed by drawing or the like, and accessories such as a lithium ion battery (not shown) and electrodes are stored in the recess 31 of the tray. Next, as shown in FIG. 3B, the lid material 33 made of the battery exterior laminate is stacked from above to wrap the battery, and the flange portion 32 of the tray and the four side edge portions 34 of the lid material 33 are heat-sealed. And seal the battery. In the storage container 35 formed by the method of placing the battery in the recess 31 of the tray, the battery can be stored from above, so that the productivity is high.

In the lithium-ion battery mounting container 30 shown in FIG. 3A described above, the depth of the tray (hereinafter, the depth of the tray may be referred to as “squeezing”) has been conventionally determined in a small lithium-ion battery. Was about 5 to 6 mm. However, in recent years, for applications such as electric vehicles, storage containers for large batteries have been required more than ever. In order to manufacture a storage container for a large battery, a tray with a deeper drawing must be formed, which increases technical difficulty.
Further, when water enters the inside of the lithium ion battery, the electrolytic solution is decomposed by the water and strong acid is generated. In this case, the strong acid generated from the inside of the laminate for the battery exterior permeates, and as a result, the aluminum foil is corroded by the strong acid and deteriorates, the electrolyte leaks, and the battery performance is only deteriorated. However, there was a problem that the lithium-ion battery could catch fire.

Japanese Unexamined Patent Publication No. 2000-357494

As a measure to prevent the surface layer of the aluminum foil and the electrode lead wire member constituting the above battery exterior laminate from being corroded by strong acid, Patent Document 1 describes by applying chromate treatment to the surface of the aluminum foil. Measures to form a chromate-treated film and improve corrosion resistance have been disclosed, but chromate treatment is a problem from the viewpoint of environmental measures because it uses chromium, which is a heavy metal, and hexavalent chromium has an effect on the human body. Since it is a harmful substance to be given, it cannot be used, and a chromate treatment solution of trivalent chromium is used. Further, there is a problem that the effect of improving corrosion resistance is weak in the chemical conversion treatment other than the chromate treatment.

Further, in the conventional electrode lead wire member, of the electrodes of both the positive electrode and the negative electrode, the aluminum material which is the electrode member of the positive electrode has good electrolytic solution resistance, but the copper plate which is the electrode member of the negative electrode is nickel-plated on the surface layer. The electrolytic solution resistance is inferior even if the chromate treatment of trivalent chromium is further applied.

The present invention has been made in view of the above circumstances, and even if the electrolytic solution of the lithium ion battery reacts with moisture to generate hydrofluoric acid and the corrosiveness increases, the adverse effect thereof is avoided and the lithium ion battery is used. It is an object of the present invention to provide an electrode lead wire member for a non-aqueous battery having improved corrosion resistance so as to extend the life of the battery.

According to the present invention, in a storage container for a non-aqueous battery using an organic electrolyte as an electrolytic solution, the outer surface of a strip-shaped metal flat plate at a portion where a laminated film laminate of an exterior material and an electrode lead wire member are joined. In addition, the technical idea is to form a protective layer in a strip-shaped pattern by printing to improve the corrosion resistance against corrosive electrolytes. This protective layer is formed by applying and drying a solution containing a polyvinyl alcohol-based resin or a polyvinyl ether-based resin and a fluorine compound.

In order to solve the above problems, the present invention is an electrode lead wire member drawn out from a storage container for a non-aqueous battery using a laminated film laminate of an aluminum foil and a resin film as an exterior material, and has a strip shape. An electrode lead wire member characterized in that a protective layer is formed by applying and drying a solution containing a polyvinyl alcohol-based resin or a polyvinyl ether-based resin and a fluorine compound on the outer surface of the metal flat plate. offer.

Further, it is preferable that the fluorine compound is water-soluble.

Further, it is preferable that the protective layer is formed in a band-shaped pattern on the outer surface of the metal flat plate by printing.

Further, it is preferable that the protective layer is crosslinked or amorphous by heat treatment to have water resistance.

The present invention also provides a storage container for non-aqueous batteries in which the electrode lead wire member is used.

Further, it is preferable that both ends of the electrode lead wire member as seen in the cross section along the joint with the exterior material are crushed so that the thickness is thinner than that of the central portion of the cross section.

After applying a solution containing a polyvinyl alcohol-based resin or a polyvinyl ether-based resin and a fluorine compound of the electrode lead wire member, the protective layer on which the protective layer is formed is crosslinked or amorphous by heat treatment. As a result, the electrode lead wire member becomes water resistant, and it is possible to suppress leakage of the electrolytic solution from both ends of the electrode lead wire member to the outside and infiltration of moisture in the atmosphere into the inside.
When both ends of the electrode lead wire member as seen in the cross section are crushed and the thickness is thinner than the central portion of the cross section, the adhesion between the electrode lead wire member and the laminated film laminate is improved and there are few gaps. Therefore, leakage of the electrolytic solution to the outside and infiltration of moisture in the atmosphere into the inside are reduced.

It is a perspective view which shows an example of the storage container for a battery. It is a schematic sectional drawing which shows an example of the exterior laminated body for a battery used for the storage container for a battery. It is a perspective view which shows the process of storing a lithium ion battery in a storage container in order. (A) is a perspective view showing an example of an electrode lead wire member according to the present invention, and (b) is a cross-sectional view taken along the SS line of (a). It is a top view which shows an example of the electrode lead wire member which concerns on this invention. It is a measurement result which measured the protective layer with a differential thermal analyzer.

The electrode lead wire member according to the present invention will be described by taking as an example a drawing from a storage container for a lithium ion battery manufactured by using a battery exterior laminate, with reference to FIGS. 1 and 2.
As shown in FIG. 1, the electrode lead wire member 18 and the lithium ion battery 17 of the present invention are contained in a battery outer container 20 formed by folding a battery outer laminate 10.
Further, the three side edge portions 19 of the battery outer container 20 are heat-sealed and made into a bag shape. The electrode lead wire member 18 is drawn out from the battery outer container 20 as shown in FIG. The storage method of the lithium ion battery manufactured by using the electrode lead wire member 18 according to the present invention in the battery storage container is shown in FIG.

As shown in FIG. 2, in the battery exterior laminate 10 made of the laminated film laminate, the base material layer 11, the aluminum foil 12, and the resin film 13 are adhered to each other via the adhesive layers 15 and 16, respectively. ing.
As shown in FIG. 4, the electrode lead wire member 18 is a strip-shaped metal flat plate 21 made of aluminum or a copper plate plated with nickel, and a polyvinyl alcohol-based resin or a polyvinyl ether-based resin (hereinafter, simply “polyvinyl ether”). A protective layer 22 formed by applying a solution containing "alcohol-based resin") and a fluorine compound and then drying the resin is laminated. The sealant layer 23 is laminated on the surface of the protective layer 22.
The protective layer 22 is formed by cross-linking a fluorine compound made of a metal fluoride or a derivative thereof and a polyvinyl alcohol-based resin to improve water resistance and activate the surface of the metal flat plate 21. Corrosion resistance can be improved. However, even if the metal fluoride or a derivative thereof is not contained, the corrosion resistance of the protective layer 22 is improved.
The protective layer 22 is formed in a strip-shaped pattern on the outer surface of the metal flat plate 21 by printing. The strip-shaped protective layer 22 formed on the outer surface of the metal flat plate 21 is crosslinked or amorphous by heat treatment to improve water resistance.
Further, by incorporating a substance such as fluorometal, which is liberated and becomes acidic in the state of an aqueous solution, in the protective layer 22, the metal surface is activated, the corrosion resistance is improved, and the metal flat plate 21 is formed. The outer surface and the protective layer 22 are strongly adhered to each other.

By the way, it is generally known that a polyvinyl alcohol-based resin having a polyvinyl alcohol skeleton has good gas barrier properties. Since the protective layer 22 of the electrode lead wire member according to the present invention is formed by using a polyvinyl alcohol-based resin, the inside of the resin constituting the protective layer 22 has few voids, especially in an atmosphere of low humidity. It also has gas barrier properties for small gas molecules such as hydrogen gas. For this reason, in a battery using a non-aqueous electrolytic solution such as a lithium battery or a capacitor, when the protective layer 22 of the present invention is used as a component inside the battery in which moisture does not exist, it is resistant to the electrolytic solution and moisture. It is considered that the battery is highly variable. Therefore, it is expected to have an effect of preventing corrosion because it has a high barrier property against substances that corrode the metal surface such as hydrofluoric acid. As described above, the protective layer 22 made of the polyvinyl alcohol-based resin can be crosslinked to improve the corrosion resistance.

As the metal flat plate 21 of the electrode lead wire member 18, a metal having an aluminum plate for the positive electrode and a copper plate coated with nickel plating for the negative electrode is generally used. In order to facilitate thermal bonding with the battery exterior laminate 10 made of an aluminum laminated film, a sealant layer 23 is formed and placed in advance on the bonding portion of the electrode lead wire member 18. The sealant layer 23 is preferably laminated on both sides so as to sandwich the metal flat plate 21 from both the front and back sides.
If the corrosion-resistant protective layer 22 is not formed on the surface layer of the metal flat plate 21, moisture and the electrolytic solution react with each other on the surface layer of the metal flat plate 21 due to the permeation of the electrolytic solution to generate hydrofluoric acid. , The metal flat plate 21 corrodes. This deteriorates the adhesion between the metal flat plate 21 and the sealant layer 23. Therefore, it is preferable that at least the surface layer surface of the metal flat plate 21 on the battery side is coated with a solution containing a polyvinyl alcohol-based resin and a fluorine compound and then dried to form the protective layer 22. As shown in FIG. 4B, it is necessary to laminate the protective layer 22 on the entire outer peripheral portion of the cross section of the metal flat plate 21 at the joint portion with the exterior material.
In the prior art, chromate treatment is widely used as a measure to prevent corrosion of the electrolytic solution of the aluminum metal flat plate 21 used for the electrode lead wire member. However, the effect of the chromate treatment is smaller on the metal flat plate 21 in which the copper is nickel-plated, as compared with the metal flat plate 21 made of aluminum. However, it was found that the electrode lead wire member 18 according to the present invention has an effect of preventing corrosion against the electrolytic solution even in the metal flat plate 21 in which copper is plated with nickel.
From this, it is considered that the corrosion prevention mechanism for the electrolytic solution by the protective layer 22 of the present invention is different from that of the conventional chromate treatment.
As shown in FIG. 5, the sealant layer 23 may be laminated so as to straddle both the positive electrode and the negative electrode. This makes it possible to obtain an electrode lead wire member in which the positive electrode and the negative electrode are integrated. Further, since the corrosion prevention effect of the protective layer 22 can be obtained for various metal plates such as an aluminum plate and a nickel-plated copper plate, it is preferable to provide the protective layer 22 on both the positive electrode and the negative electrode of the metal flat plate 21.

By the way, the protective layer 22 of the electrode lead wire member according to the present invention is formed by applying and drying a solution containing a polyvinyl alcohol-based resin and a fluorine compound. The method for producing the polyvinyl alcohol-based resin is not particularly limited, and the polyvinyl alcohol-based resin can be produced by a known method. For example, a polyvinyl alcohol-based resin can be produced by saponifying a polymer of a vinyl ester-based monomer or a copolymer thereof. In the present invention, the polyvinyl alcohol-based resin is at least one water-soluble resin selected from a polyvinyl alcohol resin and a modified polyvinyl alcohol resin. Here, as the polymer of the vinyl ester-based monomer or its copolymer, a single vinyl ester-based monomer such as a fatty acid vinyl ester such as vinyl formate, vinyl acetate, vinyl butyrate, or an aromatic vinyl ester such as vinyl benzoate alone. Examples thereof include a polymer or a copolymer, and a copolymer of another monomer copolymerizable therewith. Examples of other copolymerizable monomers include olefins such as ethylene and propylene, ether group-containing monomers such as alkyl vinyl ether, and carbonyl groups such as diacetone acrylamide, diacetone (meth) acrylate, acetoacetic acid allyl, and acetoacetic acid ester. Examples thereof include (ketone group) -containing monomers, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and maleic anhydride, vinyl halides such as vinyl chloride and vinylidene chloride, and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol-based resin is usually preferably 90 to 100 mol%, more preferably 95 mol% or more.

Examples of the polyvinyl alcohol-based resin and its derivatives that can be used in the present invention include alkyl ether-modified polyvinyl alcohol resin, carbonyl-modified polyvinyl alcohol resin, acetacetyl-modified polyvinyl alcohol resin, acetamide-modified polyvinyl alcohol resin, acrylic nitrile-modified polyvinyl alcohol resin, and carboxyl-modified. Examples thereof include polyvinyl alcohol resin, silicone-modified polyvinyl alcohol resin, and ethylene-modified polyvinyl alcohol resin. Among them, alkyl ether-modified polyvinyl alcohol resin, carbonyl-modified polyvinyl alcohol resin, carboxyl-modified polyvinyl alcohol resin, and acetoacetyl-modified polyvinyl alcohol resin are preferable.
Examples of commercially available polyvinyl alcohol-based resins that are generally available include those manufactured by Nippon Synthetic Chemistry Co., Ltd., Japan Vam & Poval Co., Ltd., and Nippon Carbide Industry Co., Ltd. As the polyvinyl alcohol-based resin, one kind or a mixture of two or more kinds may be used.

The Crosmer H series (trade name) manufactured by Nippon Carbide Industries Co., Ltd. is also known as a polyvinyl ether-based resin (vinyl ether polymer), but in the present invention, instead of the polyvinyl alcohol-based resin having a hydroxyl group, Polyvinyl ether-based resins that may or may not have a hydroxyl group can also be used. Examples of the polyvinyl ether-based resin include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, norbornenyl vinyl ether, allyl vinyl ether, norbornenyl vinyl ether, and 2-hydroxyl. Examples thereof include homopolymers or copolymers of aliphatic vinyl ethers such as ethyl vinyl ether and diethylene glycol monovinyl ether, and copolymers of other monomers copolymerizable therewith. Examples of the other monomer copolymerizable with the vinyl ether-based monomer include those similar to the other monomers copolymerizable with the vinyl ester-based monomer described above.
Polyvinyl ether-based resins containing a hydroxyl group aliphatic vinyl ether as a monomer, such as 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxypropyl vinyl ether, and other glycols and monovinyl ethers of polyhydric alcohols, are water-soluble. Moreover, since it can carry out a cross-linking reaction with a hydroxyl group, it can be suitably used in the present invention.
Since the vinyl ether monomer can be used in the resin production (polymerization) step, these polyvinyl ether-based resins undergo a saponification treatment unlike the polyvinyl alcohol-based resins produced via the vinyl ester-based polymer. It can be manufactured without any problems. Further, a copolymer containing a vinyl ester-based monomer and a vinyl ether-based monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponifying the copolymer can also be used. A mixture of a polyvinyl alcohol-based resin other than the polyvinyl ether-based resin and a polyvinyl ether-based resin can also be used.

Further, it is preferable that the protective layer 22 contains a substance that is a fluorometal or a derivative thereof and that crosslinks the polyvinyl alcohol-based resin. Fluorine compounds such as metal fluorides or derivatives thereof need to be mixed with a water-soluble polyvinyl alcohol-based resin, and thus are preferably water-soluble. Specific examples of the metal fluoride or its derivative include, for example, chromium fluoride, iron fluoride, zirconium fluoride, titanium fluoride, hafnium fluoride, zircon hydrofluoric acid and salts thereof, titanium hydrofluoric acid and their salts. Fluoride such as salt and the like can be mentioned. These fluoride metals or derivatives thereof are substances that crosslink polyvinyl alcohol-based resins and at the same time are substances containing ^{F-ions that form a passivated aluminum fluoride.} As a result, when the metal flat plate 21 is made of aluminum, it is considered that the surface of the metal flat plate 21 is passivated and the corrosion resistance is improved.

To form the protective layer 22 on the surface layer of the metal flat plate 21, for example, a polyvinyl alcohol-based resin (manufactured by Japan Synthetic Chemical Co., Ltd., Japan Vam & Poval Co., Ltd., Japan Carbide Industry Co., Ltd.) After coating with an aqueous solution in which 0.2 to 6 wt% of (manufactured, etc.) and 0.1 to 3 wt% of chromium (III) fluoride are dissolved so that the thickness after drying is about 0.1 to 5 μm. Further, the protective layer 22 can be formed by heat-drying, baking-adhesion, and cross-linking in an oven.
In FIG. 6, an aqueous solution prepared by dissolving 3 wt% of polyvinyl alcohol resin (manufactured by Nippon Synthetic Chemistry Co., Ltd.) and 1 wt% of chromium fluoride (III) was applied so as to have a thickness of 0.6 μm after drying. Further, an example of the result of measuring the protective layer formed by heat-drying in an oven at 200 ° C. with a differential thermal analyzer is shown. When the melting point was confirmed, it was found that the cross-linking occurred because there was no peak in the melting point.

When the protective layer 22 is laminated on the surface layer surface of the metal flat plate 21 in this way, the pressure-resistant strength of the protective layer 22 is high, so that even if the thickness of the polypropylene layer or the polyethylene layer, which is the sealant layer 23, is reduced. The pressure resistance can be maintained. Therefore, moisture does not easily infiltrate into the lithium ion battery from the edge portion (side edge portion) of the metal flat plate 21, and the deterioration of the electrolytic solution of the lithium ion battery with time is reduced, so that the product life of the battery is shortened. become longer.
Further, even when a small amount of water penetrates into the battery and the electrolytic solution reacts with the water to decompose the electrolytic solution to generate hydrofluoric acid, the polyvinyl laminated on the surface layer of the metal flat plate 21 is also generated. Since the protective layer 22 made of an alcohol-based resin has few voids, it has a high gas barrier property, and the generated hydrofluoric acid can be diffused to the outside of the battery along the sealant layer 23. Further, even if a small amount of hydrofluoric acid comes into contact with the surface of the aluminum plate 21 which is the metal flat plate 21, the passivation film formed on the surface of the aluminum plate prevents the metal flat plate 21 from corroding, so that the metal is metal. Since the strength of the interlayer adhesion between the flat plate 21 and the sealant layer 23 is maintained and the pressure resistance is maintained, liquid leakage of the battery does not occur.

The thickness of the sealant layer 23 bonded to the surface of the protective layer 22 is preferably 50 to 300 μm, and is most preferably 50 to 150 μm in consideration of waterproofness. If the thickness of the metal flat plate 21 is 200 μm or more, the rigidity is strong, so that a through hole may be formed in the side edge portion (edge portion) of the metal flat plate 21, and the electrolytic solution may not be completely sealed. .. Therefore, as shown in FIG. 4B, when viewed in a cross section along the joint with the exterior material, both end portions 24 of the metal flat plate 21 are crushed and the thickness is made thinner than the central portion of the cross section. Is preferable. As a result, the thickness of the sealant layer 23 bonded to the surface of the protective layer 22 can be reduced.
The thickness of the protective layer 22 made of the polyvinyl alcohol-based resin is preferably 0.1 to 5.0 μm, more preferably 0.5 to 3 μm. When the protective layer 22 has such a thickness, the performance of moisture resistance and adhesive strength is improved.

The protective layer 22 is formed on a necessary portion of the outer surface of the metal flat plate 21 by a printing method. As the printing method, a known printing method such as an inkjet method, a dispenser method, or a spray coating method can be used. The printing method that can be used in the present invention is arbitrary, but since it is necessary to print not only both surfaces of the metal flat plate 21 but also the side edge portion (edge portion) seen in the cross section of the electrode lead wire member, the inkjet method is used. And the dispenser method is good. In particular, in the dispenser method, when an experiment was conducted using a coating head capable of printing in a narrow width of about 10 mm, it was found to be the most suitable method.
As the sealant layer 23 bonded to the surface of the protective layer 22 of the electrode lead wire member, it is preferable to use the same or similar resin film as the resin film 13 used for the innermost layer of the aluminum laminated film 10. When the resin film 13 is generally used polypropylene, the sealant layer 23 is modified with unstretched polypropylene (CPP), a film of maleic anhydride-modified propylene alone, or a monomer having an epoxy functional group such as glycidyl methacrylate. It may be a single film of polypropylene, or a multilayer film of polypropylene. When the resin film 13 is polyethylene, the sealant layer 23 may be polyethylene, maleic anhydride-modified polyethylene, or polyethylene modified with a monomer having an epoxy functional group such as glycidyl methacrylate, and further, polyethylene and polyethylene. And a multilayer film with the copolymer thereof may be used. In this case, the surface in contact with the electrolytic solution may be a copolymer of maleic anhydride or acrylic acid, polyethylene modified with glycidyl methacrylate or the like.

Examples of the non-aqueous battery in which the present invention is used include those using an organic electrolyte as an electrolytic solution such as a lithium ion battery which is a secondary battery and an electric double layer capacitor. As the organic electrolyte, those using carbonic acid esters such as propylene carbonate (PC), diethyl carbonate (DEC), and ethylene carbonate as a medium are generally used, but the organic electrolyte is not particularly limited thereto.

(Measuring method)
-Measurement method of adhesive strength between the metal flat plate of the electrode lead wire member and the sealant layer: Using a measurement sample in which an aluminum laminate film is heat-sealed on the sealant layer, JIS C6471 "Copper-clad laminate for flexible printed wiring board" The measurement was performed by the measurement method specified in "Test method".
-Measuring method of electrolyte strength retention rate: Using a battery exterior laminate, a bag was made into a 4-sided bag of 50 x 50 mm (heat seal width 5 mm), and 1 mol / liter of _{LiPF 6 was added thereto.} 0.5 wt% of pure water was added to the PC / DEC electrolytic solution, and 2 cc of the pure water was weighed, filled and packaged. In this four-sided bag, a protective layer was printed on a part of the outer surface of the metal flat plate of the electrode lead wire member by a dispenser method. An electrode lead wire member having a sealant layer laminated by heat sealing is placed on the protective layer, and after storage in an oven at 60 ° C. for 100 hours, the interlayer adhesion strength between the protective layer of the electrode lead wire member and the sealant layer ( Measure k2).
Here, the interlayer adhesion strength (k1) between the protective layer before exposure to the electrolytic solution and the polypropylene (PP) film which is the sealant layer, which was measured in advance, and the interlayer adhesion strength after exposure to the electrolytic solution. The ratio with (k2) was defined as the electrolytic solution strength retention rate K = (k2 / k1) × 100 (%).
(measuring device)
・ Adhesive strength measuring device: manufactured by Shimadzu Corporation, model: AUTOGRAPH AGS-100A tensile test device

(Example 1)
As a metal flat plate of the electrode lead wire member for a lithium battery, an aluminum piece obtained by cutting an aluminum plate having a thickness of 200 μm into a size of 50 mm × 60 mm was used. On the surface of this degreased and washed aluminum piece, an aqueous solution in which 3 wt% of polyvinyl alcohol resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 1 wt% of chromium fluoride (III) are dissolved is used, and the thickness after drying is 1 μm. Both sides were coated with a 10 mm wide type dispenser so as to be, and a protective layer was laminated. Further, it was heated and dried in an oven at 200 ° C., and the resin of the protective layer was crosslinked at the same time as baking. At this time, it was confirmed that the protective layer was formed not only on the surface layers of both surfaces of the metal flat plate but also on the side edges (both end surfaces) of the metal flat plate.
Further, on the surface of the protective layer on the outer surface of the metal flat plate, a single-layer film of maleic anhydride-modified polypropylene film (polypropylene resin manufactured by Mitsui Chemicals, product name / Admer QE060) is formed to 100 μm by a film forming machine. The film was used) was bonded on both sides with a heat seal to obtain the electrode lead wire member of Example 1.
An aluminum laminate film having a thickness of 120 μm, which is made of an aluminum foil (thickness 20 μm) / anhydrous maleic acid-modified polypropylene film (thickness 100 μm), is heat-sealed on the sealant layer of the electrode lead wire member of Example 1 to form Example 1. A measurement sample was prepared using the electrode lead wire member of.
A test piece for measuring the adhesive strength was taken from the measurement sample of Example 1, and the adhesive strength between the metal flat plate and the sealant layer was measured. As a result, the adhesive strength was 46 N / inch.
Further, the result of measuring the electrolytic solution strength retention rate K for the measurement sample of Example 1 was K = 88%.

(Example 2)
As a metal flat plate of an electrode lead wire member for a lithium battery, a copper plate piece (dimensions 50 mm × 60 mm) having a thickness of 200 μm is plated with nickel sulfamic acid to a thickness of 2 to 5 μm, and a part thereof is made of polyvinyl alcohol. Using an aqueous solution prepared by dissolving 3 wt% of a system resin (manufactured by Nippon Synthetic Chemical Co., Ltd.) and 1 wt% of chromium fluoride (III), it was applied so that the thickness after drying was 1 μm, and a protective layer was laminated. .. Further, it was heated and dried in an oven at 200 ° C., and the resin of the protective layer was crosslinked at the same time as baking.
Further, a film obtained by forming a single layer of maleic anhydride-modified polypropylene film (polypropylene resin manufactured by Mitsui Chemicals, product name / Admer QE060) to 100 μm on the surface of the protective layer on the outer surface of the metal flat plate with a film forming machine. Was heat-sealed on both sides to obtain the electrode lead wire member of Example 2.
Using the electrode lead wire member of Example 2, the aluminum laminated film was heat-sealed in the same manner as in Example 1 to obtain a measurement sample of Example 2, and the adhesive strength between the metal flat plate and the sealant layer was measured. , 44N / inch adhesive strength was shown.
Further, the result of measuring the electrolytic solution strength retention rate K for a part of the battery storage container of Example 2 was K = 78%.

(Example 3)
After drying, use an aqueous solution in which 2 wt% of polyvinyl alcohol resin (manufactured by Japan Vam & Poval Co., Ltd.) and 2 wt% of chromium (III) fluoride are dissolved as an aqueous solution to be applied to a part of a metal flat plate. The electrode lead wire member and the measurement sample of Example 3 were obtained in the same manner as in Example 2 except that the thickness of the metal was 0.8 μm and the protective layer was laminated.
When the adhesive strength between the metal flat plate and the sealant layer was measured for the electrode lead wire member and the measurement sample of Example 3, the adhesive strength of 44 N / inch was shown.
Further, the result of measuring the electrolytic solution strength retention rate K for a part of the battery storage container of Example 3 was K = 74%.

(Example 4)
As an aqueous solution to be applied to a part of a metal flat plate, an aqueous solution prepared by dissolving 2 wt% of polyvinyl alcohol resin (manufactured by Nippon Carbide Industries Co., Ltd.) and 2 wt% of chromium (III) fluoride is used, and the thickness after drying is used. The electrode lead wire member and the measurement sample of Example 4 were obtained in the same manner as in Example 2 except that the thickness was 0.8 μm and the protective layer was laminated.
When the adhesive strength between the metal flat plate and the sealant layer was measured for the electrode lead wire member and the measurement sample of Example 4, the adhesive strength of 46 N / inch was shown.
Further, the result of measuring the electrolytic solution strength retention rate K for a part of the battery storage container of Example 4 was K = 77%.

(Comparative Example 1)
In the same manner as in Example 1 except that the protective layer was not laminated on the aluminum plate, the electrode lead wire member and the measurement sample of Comparative Example 1 were obtained, and the adhesive strength between the metal flat plate and the sealant layer was measured. The adhesive strength of / inch was shown. Further, the result of measuring the electrolytic solution strength retention rate K with respect to the measurement sample of Comparative Example 1 was K = 10% or less.

(Comparative Example 2)
As a metal flat plate of the electrode lead wire member for a lithium battery, the surface of a copper plate piece (dimensions 50 mm × 60 mm) with a thickness of 200 μm is plated with nickel sulfamic acid of about 2 to 5 μm, and a part thereof is polyvinyl alcohol-based. Using a paint mixed with 3 wt% of resin (manufactured by Nippon Synthetic Chemical Co., Ltd.) and 1 wt% of chromium (III) fluoride, the coating was applied so that the thickness after drying was 1 μm, and a protective layer was laminated. The electrode lead wire member and the measurement sample of Comparative Example 2 were obtained in the same manner as in Example 1 except that the heat-drying treatment was not performed after the laminating.
When the adhesive strength between the metal flat plate and the sealant layer was measured for the electrode lead wire member and the measurement sample of Comparative Example 2, the adhesive strength was 46 N / inch. Further, the result of measuring the electrolytic solution strength retention rate K with respect to the measurement sample of Comparative Example 2 was K = 10% or less. After measuring the electrolyte strength retention rate, a peeling phenomenon (derami) occurred between the metal flat plate of the electrode lead wire member and the sealant layer due to exposure to the electrolyte.

The above results are summarized in Table 1. In Table 1, the "adhesive strength between the metal flat plate of the electrode lead wire member and the sealant layer" is simply "adhesive strength".

In Examples 1 and 2, Nippon Synthetic Chemistry Co., Ltd. was used as the polyvinyl alcohol-based resin. In Example 3, Japan Vam & Poval Co., Ltd. was used as the polyvinyl alcohol-based resin. In Example 4, Nippon Carbide Industries Co., Ltd. was used as the polyvinyl alcohol-based resin. In Examples 1 to 4, the metal flat plate of the electrode lead wire member is coated with a paint containing 3 wt% or 2 wt% of these polyvinyl alcohol-based resins and 1 wt% or 2 wt% of chromium (III) fluoride. However, since the protective layer is formed, the adhesive strength between the metal flat plate of the electrode lead wire member and the sealant layer is 40 N / inch or more. Further, the electrode lead wire member in which the protective layer was applied between the sealant layer and the metal flat plate was resistant to the electrolytic solution of the lithium battery and had high withstand voltage strength.
On the other hand, Comparative Example 1 is a case where the protective layer is not formed on the electrode lead wire member, but the adhesive strength between the metal flat plate of the electrode lead wire member and the sealant layer is as high as 54 N / inch. The electrolytic solution strength retention rate K is 10% or less, and there is no electrolytic solution resistance.
Further, Comparative Example 2 is a case where the protective layer is not heat-dried even if the protective layer is applied to the electrode lead wire member, but the adhesive strength between the metal flat plate of the electrode lead wire member and the sealant layer is 46 N /. Although it is an inch, the electrolytic solution strength retention rate K is 10% or less and there is no electrolytic solution resistance.

10 ... Battery exterior laminate, 11 ... Base material layer, 12 ... Aluminum foil, 13 ... Resin film, 15, 16 ... Adhesive layer, 17 ... Lithium ion battery, 18 ... Electrode lead wire member, 19 ... Side edge , 20 ... Battery exterior container, 21 ... Metal flat plate, 22 ... Protective layer, 23 ... Sealant layer, 30 ... Battery mounting container, 35 ... Battery storage container.

Claims (2)

A solution containing a polyvinyl alcohol-based resin or a polyvinyl ether-based resin and a water-soluble fluorine compound on the outer surface of a strip-shaped metal flat plate, which is an electrode lead wire member drawn out from a storage container for a non-aqueous battery. A protective layer is formed by applying and drying the protective layer, and the sealant layer is laminated on the surface of the protective layer.
The water-soluble fluorine compound is a metal fluoride or a derivative thereof, and is
The protective layer is crosslinked by heat treatment to have water resistance , and is a crosslinked body composed of a polyvinyl alcohol-based resin or a polyvinyl ether-based resin and a water-soluble fluorine compound.
An electrode lead wire member characterized in that the value of the electrolyte strength retention rate K of the electrode lead wire member measured based on the following "method for measuring the electrolyte strength retention rate" exceeds 10%.
-Measuring method of electrolyte strength retention rate: Using a battery exterior laminate, a bag was made into a 4-sided bag of 50 x 50 mm (heat seal width 5 mm), and 1 mol / liter of _{LiPF 6 was added thereto.} 2cc of propylene carbonate (PC) / diethyl carbonate (DEC) electrolytic solution (electrolyzate to which 0.5 wt% of pure water is added) is weighed, filled and packaged, and the electrode lead wire member is placed in the four-sided bag. A protective layer is printed on a part of the outer surface of the metal flat plate by a dispenser method, and an electrode lead wire member having a sealant layer laminated by heat sealing is placed on the protective layer and placed in an oven at 60 ° C. for 100. After storage for a long time, the interlayer adhesion strength (k2) between the protective layer of the electrode lead wire member and the sealant layer was measured, and polypropylene which was measured in advance and was the protective layer and the sealant layer before being exposed to the electrolytic solution. The ratio of the interlayer adhesion strength (k1) to the (PP) film and the interlayer adhesion strength (k2) after exposure to the electrolytic solution is the electrolytic solution strength retention rate K = (k2 / k1) × 100 (%). do. A storage container for a non-aqueous battery using the electrode lead wire member according to claim 1.

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