Sumitomo Chemical Company, Limited

Eiko Kashiwazaki

Chikara Murakami

Ichiro Arise

Toshihiko Ogata

Kosuke Kurakane

A nonaqueous electrolyte secondary battery includes: a separator including a polyolefin porous film; a porous layer containing a polyvinylidene fluoride-based resin; a positive electrode plate having a capacitance falling within a specific range; and a negative electrode plate having a capacitance falling within a specific range. The polyolefin porous film has a given piercing strength, having a value of not less than 0.00 and not more than 0.54, the value being represented by the following expression: |1&#x2212;T/M|, where T and M are distances at which a critical load is reached in a scratch test in which the polyolefin porous film is moved in transverse and machine directions, respectively, under a constant load of 0.1N. The polyvinylidene fluoride-based resin contains an &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.

Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery including: a nonaqueous electrolyte secondary battery separator including a polyolefin porous film; a porous layer containing a polyvinylidene fluoride-based resin; a positive electrode plate having a capacitance falling within a specific range; and a negative electrode plate having a capacitance falling within a specific range, wherein: the polyolefin porous film has a given rate of diminution of diethyl carbonate and a given spot diameter of the diethyl carbonate; the porous layer is provided between the nonaqueous electrolyte secondary battery separator and at least one of the positive electrode plate and the negative electrode plate; and the polyvinylidene fluoride-based resin contained in the porous layer contains an &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.

With a nonaqueous electrolyte secondary battery separator having a radical concentration of 5000&#xd7;10spins/mg to 90000&#xd7;10spins/mg, wherein the concentration is calculated from a peak at a g-value of not less than 2.010 in an electron spin resonance spectrum obtained through electron spin resonance analysis using a microwave having a frequency of 9.4 GHz, it is possible to provide a nonaqueous electrolyte secondary battery having a high battery resistance decreasing rate before and after battery formation.

Nonaqueous electrolyte secondary battery separator

As a nonaqueous electrolyte secondary battery whose battery performance is prevented from being deteriorated by charge and discharge, provided is a nonaqueous electrolyte secondary battery including: a nonaqueous electrolyte secondary battery separator having ion permeability barrier energy of not less than 300 J/mol/&#x3bc;m and not more than 900 J/mol/&#x3bc;m per unit film thickness; and a nonaqueous electrolyte containing a given additive in an amount of not less than 0.5 ppm and not more than 300 ppm.

Growing community of inventors

Osaka, Japan

Eiko Kashiwazaki