JPH10247503A - Adhesive or pressure sensitive adhesive or pressure sensitive adhesive tape sheet to fasten battery element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the functional deterioration of electrolyte by reacting with electrolytic salt and the like on the inside of a battery, and prevent the exertion of adverse influence on a battery characteristic by specifying an unsaturation degree of an adhesive or a pressure sensitive adhesive only to fasten a battery element formed by winding or laminating a positive electrode and a negative electrode through a separator. SOLUTION: An adhesive or a pressure sensitive adhesive on which as an unsaturation degree an iodine value is not more than 10 and/or an unsaturation degree of an NMR method is 0.5[10<-2> mol/g] is used. For example, an independent or mixture of such as a polypropylene oligomer, a polyethylene oligomer, polyisoprene, a trifluorochlorimethyl ethylene-vinylidene fluoride copolymer, and polydimethyl siloxane or a material by blending a pressure sensitive adhesion imparting resin such as a hydrogenation terpene resin and a hydrogenation rosin resin with these are cited. There are used to unseaparadly bind a positive electrode, a negative electrode and a separator of a battery element 1. A pressure sensitive adhesive tape 2 or a sheet where a pressure sensitive adhesive is arranged at least on one surface of a base material, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive or pressure-sensitive adhesive or a pressure-sensitive adhesive tape for fixing a battery element formed by winding or laminating a positive electrode and a negative electrode of a battery via a separator so that the battery element does not come apart. The present invention relates to a sheet (hereinafter, sometimes simply referred to as an adhesive tape).

[0002]

In the battery manufacturing process, as shown in FIG. 1, a battery element 1 in which a positive electrode and a negative electrode are spirally wound via a separator is housed in a battery case. To prevent the battery element 1 from being unwound, various adhesives, adhesives or adhesive tapes 2 are used on the outermost periphery of the battery element 1. Also, as shown in FIG. 2, even when the battery element 1 in which the positive electrode and the negative electrode are stacked with the separator interposed therebetween is housed in a battery case, the battery element 1 is not separated.
Various adhesives, adhesives or adhesive tapes 2 are used to bind the respective positive electrodes, negative electrodes, and separators. The constituent material of the adhesive or pressure-sensitive adhesive used here is selected mainly in consideration of the adhesiveness with the adherend, but when such an adhesive or pressure-sensitive adhesive is used inside the battery, Even if the battery is selected in consideration of the above points, there is a problem that the battery characteristics still deteriorate. This is because the electrolyte (various salts) in the electrolytic solution reacts with the adhesive or pressure-sensitive adhesive component inside the battery, and bonds with other components or promotes self-decomposition of various salts occurs, thereby deteriorating the function of the electrolyte. However, as a result, it is considered that the battery characteristics are adversely affected. However, hitherto, when selecting an adhesive or a pressure-sensitive adhesive to be used for fixing the battery element, no selection has been made in consideration of the reactivity of the battery electrolyte with respect to the electrolyte (various salts).

[0003]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve such a problem, and as a result, as an adhesive or a pressure-sensitive adhesive for stopping the battery element from scattering, a specific degree of unsaturation was obtained. Is used to satisfy the adhesive and pressure-sensitive properties originally required for the adhesive or pressure-sensitive adhesive, and to promote binding or decomposition by reaction between the electrolyte salt and the adhesive or pressure-sensitive adhesive component inside the battery. Have been found to have no adverse effect on battery characteristics because the electrolyte function is not reduced and the function of the electrolyte is not reduced, and the present invention has been accomplished.

That is, the present invention relates to an adhesive or pressure-sensitive adhesive for stopping a battery element in which a positive electrode and a negative electrode are wound or laminated via a separator, and has an iodine value of 10 or less as an unsaturation degree, and / or Provided are an adhesive or pressure-sensitive adhesive for fixing a battery element, wherein the degree of unsaturation by NMR is 0.5 [10 ^-2 mol / g] or less, and a pressure-sensitive adhesive tape / sheet using the pressure-sensitive adhesive. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive or pressure-sensitive adhesive for fixing a battery element according to the present invention has an iodine value of 10 or less, preferably 5 or less as an unsaturated degree from the viewpoint of reactivity with electrolyte salts, or / And the degree of unsaturation by NMR method is 0.5 [10 ^-2
mol / g] or less, preferably 0.1 [10 ^-2 mol / g] or less. The iodine value as the degree of unsaturation exceeds 10, and the degree of unsaturation by NMR method is 0.1.
If the concentration exceeds 5 [10 ^-2 mol / g], the electrolyte (various salts) in the electrolyte reacts with the adhesive or pressure-sensitive adhesive component inside the battery to bond with other components or to form the various salts. It is not preferable because decomposition may be accelerated and the function of the electrolyte may be reduced.

Here, the above-mentioned iodine value is measured according to JIS K 0070, and the degree of unsaturation by NMR method is obtained by measuring the peak area of a proton derived from an olefin in the proton NMR measurement. Is calculated using the peak area of the sample for which is known as a standard.

The specific constituent material of the adhesive or pressure-sensitive adhesive for fixing a battery element of the present invention is not particularly limited as long as it has the above-mentioned specific degree of unsaturation. For example, polypropylene oligomer, polyethylene oligomer, polyisobutylene, trifluoro Chloroethylene-vinylidene fluoride copolymer, polydimethyl siloxane alone or a mixture thereof, and further, a hydrogenated terpene resin, a tackifying resin such as a hydrogenated rosin resin, and, if necessary, various additives were blended. Things. Even when the degree of unsaturation of the constituent material used is equal to or more than the above value, the unsaturated group can be modified by a method such as catalytic hydrogenation so that the degree of unsaturation falls within the above range.

The effect of the adhesive or pressure-sensitive adhesive for fixing a battery element of the present invention on battery characteristics can be evaluated by an electrolytic solution coloring test in Examples described later. That is, it is considered that the coloring occurs when various salts (for example, lithium salts), which are electrolytes in the electrolytic solution, are degraded due to self-decomposition or bonding with other components.

The present invention also provides a pressure-sensitive adhesive tape / sheet for fixing a battery element, wherein the pressure-sensitive adhesive is suitably provided on at least one surface of a substrate. Such a substrate is not particularly limited, but includes, for example, OPP (stretched polypropylene), polyethylene, polyimide, polyester, fluororesin,
Films such as polymethylpentene, syndiotactic polystyrene, polyphenylene sulfide, blends of polyethylene and polypropylene, and composites of these with glass fibers. In addition, it is preferable to select those base materials that do not contain impurities that promote self-decomposition of the electrolytic solution or bond with other components and do not easily elute into the electrolytic solution.

[0010]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Examples 1 to 7 and Comparative Examples 1 and 2 Adhesives or pressure-sensitive adhesives having the composition shown in Table 1 were obtained, and their adhesive strength, degree of unsaturation, and electrolytic solution discoloration were evaluated by the following methods. It is shown in Table 2.

[0011]

[Table 1]

[Adhesive strength] Oriented polypropylene (OPP)
Adhesive tape obtained by applying the obtained adhesive or pressure-sensitive adhesive to a film (thickness: 30 μm) with a thickness of 30 μm, is attached to a stainless steel plate, and the load when this adhesive tape is peeled off by 180 ° peel Was measured. [Anchoring property of battery element] The adhesive tape obtained above was adhered and fixed to the outermost periphery of the battery element 1 as shown in FIGS. 1 and 2, and when the battery element 1 was inserted into the battery case, the battery element was 1 did not come apart, or the battery element 1 was easily held, and workability was improved. [Unsaturation (iodine value)] Measured according to JIS K0070. [Degree of Unsaturation (NMR Method)] In proton NMR measurement, the peak area of a proton derived from an olefin was calculated using the peak area of a sample having a known degree of unsaturation as a standard. [Electrolytic Solution Discoloration (Electrolytic Solution Coloring Test)] Ethylene carbonate (EC): dimethyl carbonate (DMC): diethyl carbonate (DEC) as a solvent (electrolytic solution)
= 1: 1: 1 (volume ratio) and 1 mol / dm ^{3 of} lithium hexafluorophosphate (LiPF ₆ ) as a solute (electrolyte) was replaced with an argon-substituted sample. Under an environment, the sample: electrolyte solution was added at 1: 200 (weight ratio) and sealed. After storage at 60 ° C. for one week, the degree of color development of the electrolyte was visually compared with the electrolyte without the sample as a blank. In addition,
It is considered that the color development occurs when the lithium salt, which is the electrolyte in the electrolytic solution, changes in quality due to self-decomposition or bonding with other components.

[0013]

[Table 2]

[0014]

The adhesive or pressure-sensitive adhesive for fixing a battery element according to the present invention satisfies the adhesive and pressure-sensitive adhesive properties to an adherend originally required for the adhesive or pressure-sensitive adhesive, and is free from electrolyte salts inside the battery. A battery with high characteristics and high reliability because the reaction with an adhesive or a pressure-sensitive adhesive component reduces the occurrence of bonding or decomposition promotion and the like, so that the function of the electrolyte is not reduced and the battery characteristics are not adversely affected. There is an advantage that can be created.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a usage example of the pressure-sensitive adhesive tape of the present invention.

FIG. 2 is a schematic view showing a usage example of the pressure-sensitive adhesive tape of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery element 2 Adhesive tape

Continued on the front page (72) Inventor Toshimitsu Okuno 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (2)

[Claims] 1. An adhesive or pressure-sensitive adhesive for stopping a battery element in which a positive electrode and a negative electrode are wound or laminated via a separator, and has an iodine value of 10 as an unsaturation degree.
And / or the degree of unsaturation by NMR method is 0.5 [10
^-2 mol / g] or less. 2. A pressure-sensitive adhesive tape / sheet for fixing a battery element, wherein the pressure-sensitive adhesive according to claim 1 is provided on at least one surface of a substrate.