Sumitomo Chemical Company, Limited

Sumitomo Chemical Companylimited

Toshihiko Ogata

Chikara Murakami

Ichiro Arise

Kosuke Kurakane

Chikae Yoshimaru

Junji Suzuki

Hiroki Hashiwaki

Eiko Kashiwazaki

Daizaburo Yashiki

Takahiro Matsuo

The present invention provides a nonaqueous electrolyte secondary battery in which a decrease in discharge capacity after a charge-discharge cycle is reduced. The nonaqueous electrolyte secondary battery in accordance with an aspect of the present invention includes (i) a positive electrode plate and a negative electrode plate whose results of a scratch test carried out in the TD and the MD fall within predetermined ranges, (ii) a nonaqueous electrolyte secondary battery separator that includes a porous film whose temperature rise ending period with respect to a resin amount per unit area at irradiation with microwave falls within a predetermined range, and (iii) a porous layer that contains an &#x3b1;-form polyvinylidene fluoride-based resin of a polyvinylidene fluoride-based resin at a predetermined proportion. The porous layer is arranged between the nonaqueous electrolyte secondary battery separator and at least one of the positive electrode plate and the negative electrode plate.

Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery including: a separator including a polyolefin porous film; a porous layer containing a polyvinylidene fluoride-based resin; a positive electrode plate whose active material layer is not peeled from the positive electrode plate until the positive electrode plate is bent 130 or more times; and a negative electrode plate whose active material layer is not peeled from the negative electrode plate until the negative electrode plate is bent 1650 or more times, wherein: diethyl carbonate dropped on the polyolefin porous film diminishes at a rate of 15 sec/mg to 21 sec/mg; the diethyl carbonate has a spot diameter of not less than 20 mm 10 seconds after the diethyl carbonate was dropped on the polyolefin porous film; and the polyvinylidene fluoride-based resin contains an &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.

A nonaqueous electrolyte secondary battery includes: a separator including a polyolefin porous film; a porous layer containing a polyvinylidene fluoride-based resin; and a positive electrode plate and a negative electrode plate for each of which the result of a scratch test in the width direction and the result of a scratch test in the flow direction are each within a predetermined range, the polyvinylidene fluoride-based resin containing an &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.

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 %.

A nonaqueous electrolyte secondary battery which satisfies four requirements is provided. A porous layer contains &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol % with respect to 100 mol % of a total amount of (i) the &#x3b1;-form polyvinylidene fluoride-based resin and (ii) &#x3b2;-form polyvinylidene fluoride-based resin. A porous film has a temperature rise ending period of 2.9 sec&#xb7;m/g to 5.7 sec&#xb7;m/g with respect to an amount of a resin per unit area when the porous film is impregnated with N-methylpyrrolidone containing water in an amount of 3% by weight and then (ii) irradiated, at an output of 1,800 W, with a microwave having a frequency of 2,455 MHz. A positive electrode plate has a capacitance of 1 nF to 1000 nF per measurement area of 900 mm. A negative electrode plate has a capacitance of 4 nF to 8500 nF per measurement area of 900 mm.

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 %.

A laminated separator for a nonaqueous electrolyte secondary battery, (i) includes a porous film and a porous layer containing a polyvinylidene fluoride-based resin and (ii) has an excellent rate characteristic. The laminated separator includes the porous film containing a polyolefin-based resin as a main component and the porous layer containing the polyvinylidene fluoride-based resin, in which a surface of the porous layer has a 60-degree specular gloss of 3% to 26%.

Method of producing laminated separator for nonaqueous electrolyte secondary battery

Provided are a separator capable of being used for a secondary battery such as a nonaqueous electrolyte-solution secondary battery and a secondary battery including the separator. A separator having a first layer including a porous polyethylene and an organic additive is provided. A white index of the first layer is equal to or more than 85 and equal to or less than 98, and a reduction rate of diethyl carbonate dropped on the first layer is equal to or higher than 0.048 mg/s and equal to or lower than 0.067 mg/s. The separator may further include a porous layer over the first layer.

Separator and secondary battery including the separator

The present invention provides a nonaqueous electrolyte secondary battery containing (i) a separator containing a polyolefin porous film, (ii) a porous layer containing a polyvinylidene fluoride-based resin, (iii) a positive electrode plate having a capacitance falling within a certain range, and (iv) a negative electrode plate having a capacitance falling within a certain range, the polyvinylidene fluoride-based resin containing an &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.

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; and a negative electrode plate, wherein a sum of interface barrier energies being a predetermined value, the polyolefin porous film having a puncture strength of a predetermined value, the value represented by Formula (1) below being not less than 0.00 and not more than 0.54,|1&#x2212;&#x2003;&#x2003;Formula (1),and the polyvinylidene fluoride-based resin containing an &#x3b1;-form polyvinylidene fluoride-based resin in an amount of not less than 35.0 mol %.

A nonaqueous electrolyte secondary battery in accordance with an embodiment of the present invention includes: a separator including a polyolefin porous film; a porous layer containing a polyvinylidene fluoride-based resin; and a positive electrode plate and a negative electrode plate each of which has a capacitance in a specific range, the polyolefin porous film having a parameter X of not more than 20, and the polyvinylidene fluoride-based resin containing not less than 35.0 mol % of an &#x3b1;-form polyvinylidene fluoride-based resin.

An adhesive layer disposed between a separator for a secondary battery and an electrode for a secondary battery, wherein the adhesive layer is obtained by bonding under pressure a layer containing a resin having a structural unit derived from an &#x3b1;-olefin having 2 to 4 carbon atoms, and an occupancy area of the resin in the adhesive layer is 10 to 80%.

Adhesive layer, layer, and composition

The present invention improves productivity of production of a nonaqueous electrolyte secondary battery. A nonaqueous electrolyte secondary battery insulating porous layer in accordance with an embodiment of the present invention is a constituent member of a nonaqueous electrolyte secondary battery laminated separator, includes a thermoplastic resin, has a porosity of 25% to 80%, and has a peeling strength of above 0 N/m to 2.0 N/m when press-bonded to a nonaqueous electrolyte secondary battery electrode at 25&#xb0; C. through two one-minute 30 kN applications, the nonaqueous electrolyte secondary battery electrode containing an electrode active material, an electrically conductive agent, and a binding agent in a mass fraction of 92:2.7:5.3.

Nonaqueous electrolyte secondary battery insulating porous layer

A nonaqueous electrolyte secondary battery separator having a laminated body which is not easily curled is provided. The laminated body includes a porous base material containing a polyolefin-based resin as a main component and a porous layer which is disposed on at least one surface of the porous base material and which contains a polyvinylidene fluoride-based resin. The porous base material has a piercing strength of not less than 26.0 gf/g/m. The polyvinylidene fluoride-based resin contains crystal form &#x3b1; in an amount of not less than 36 mol % with respect to 100 mol % of a total amount of the crystal form &#x3b1; and crystal form &#x3b2; contained in the polyvinylidene fluoride-based resin.

Laminated body

To afford a laminated body that is usable as a nonaqueous electrolyte secondary battery separator and that is not easily curled, a laminated body includes: a porous base material containing a polyolefin-based resin as a main component; and a porous layer containing a polyvinylidene fluoride-based resin, the porous base material having a parameter X of not more than 20, the parameter X being calculated in accordance with a particular formula, the polyvinylidene fluoride-based resin containing crystal form &#x3b1; in an amount of not less than 36 mol % with respect to 100 mol % of a total amount of the crystal form &#x3b1; and crystal form &#x3b2; contained in the polyvinylidene fluoride-based resin.

Growing community of inventors

Osaka, Japan

Toshihiko Ogata