Adhesive tape for electrochemical device

Abstract

To provide a pressure-sensitive adhesive tape for an electrochemical device that has an extremely low water content, that is unlikely to lead to "adhesive protrusion", and that is not removed even when it is in contact with an electrolytic solution. The pressure-sensitive adhesive tape for an electrochemical device of the present invention includes a pressure-sensitive adhesive layer composed of an acrylic pressure-sensitive adhesive on at least one side of a plastic base, and is characterized by including the pressure-sensitive adhesive layer having a gel content of 60% or more and a thickness of 1 to 15 [mu]m, and by having a water absorption rate of 0.2% or less after immersion in water at 23 DEG C for 24 hours. It is preferable that the acrylic pressure-sensitive adhesive is a copolymer of a monomer component including at least an alkyl (meth)acrylate containing an alkyl group having 6 to 10 carbon atoms and a monomer containing a group reactive with isocyanate, and that the monomer component includes the alkyl (meth)acrylate containing an alkyl group having 6 to 10 carbon atoms in an amount of 80% by weight or more.

Description

technical field [0001] The present invention relates to an adhesive tape for an electrochemical device, and more particularly, to an adhesive tape used for a portion that is in contact with an electrolytic solution or a portion that may be in contact with an electrolytic solution in the assembly of an electrolytic capacitor, a lithium ion battery, and the like. Background technique [0002] Electrochemical devices often use adhesive tapes in the manufacturing process. For example, in the manufacturing process of lithium-ion batteries, when preventing the penetration of the separator due to foreign matter, burrs, etc., preventing the peeling of the active material, and winding the laminated body of the electrode plate and the separator, etc., into the battery case Adhesive tape is used for various purposes such as fixing the tail of a roll. [0003] In particular, for adhesive tapes that are bonded to parts that may come into contact with electrolyte solutions, such as insid...

AI Technical Summary

Problems solved by technology

However, when the thickness of the adhesive layer is reduced, the above-mentioned "adhesive bleeding" does not easily occur, but there is a problem that the adhesiveness becomes insufficient.

This is because when the adhesive tape is peeled off in the electrolytic solution, the active material falls off, and the adhesive component eluted into the electrolytic solution reacts with the electrolyte, thereby degrading the characteristics of the electrolytic solution and battery (Patent Document 1, etc.)

[0005] In addition, the adhesive tape is mainly composed of a base material and an adhesive. However, it is known that a common adhesive tape absorbs and retains moisture in the air in the base material and the adhesive layer. When used in electrochemical devices, defects in electrochemical devices will occur due to the release of moisture retained in the substrate and adhesive layer into the electrolyte

In particular, the lithium salt in the electrolyte solution of a lithium-ion battery has high reactivity, and immediately reduces and decomposes the water released into the electrolyte solution, which causes an increase in the internal pressure of the battery, corrosion of battery components, etc., and the battery characteristics are likely to deteriorate.

[0006] That is, the present situation is that there is no adhesive tape for electrochemical devices that does not easily cause "adhesive bleeding", has excellent adhesiveness, and has an extremely low moisture content.

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