Sumitomo Chemical Company, Limited

Kosuke Kurakane

Chikara Murakami

Toshihiko Ogata

Ichiro Arise

Chikae Yoshimaru

Shizuka Iwata

Junji Suzuki

Takahiro Okugawa

Syusaku Hara

Yutaka Suzuki

Eiko Kashiwazaki

Tomoaki Ozeki

Takuji Yamamoto

An aspect of the present invention achieves a nonaqueous electrolyte secondary battery laminated separator which has excellent heat resistance and exhibits an excellent initial battery characteristic when used in a nonaqueous electrolyte secondary battery. A nonaqueous electrolyte secondary battery laminated separator in accordance with an aspect of the present invention includes: a polyolefin porous film; and a porous layer which (i) is disposed on at least one surface of the polyolefin porous film and (ii) includes a heat resistant filler, the porous layer having a surface which has cracks, a ratio of a total area of the cracks to a surface area of the porous layer being 0.15% to 10%.

Nonaqueous electrolyte secondary battery laminated separator

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 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 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 %.

The present invention provides a nonaqueous electrolyte secondary battery having excellent battery characteristics, including a battery separator containing a polyolefin porous film; a positive electrode plate; and a negative electrode plate. The polyolefin porous film has a puncture strength of at least 26.0 gf/g/mand satisfies Formula (A), and the positive and negative electrode plates satisfy Formula (B).0.00&#x2264;|1&#x2212;|&#x2264;0.54&#x2003;&#x2003;(A)0.00&#x2264;|1&#x2212;|&#x2264;0.50&#x2003;&#x2003;(B)T represents a distance by which the polyolefin porous film or positive or negative electrode plate moves in a traverse direction from a starting point to a point where a critical load is obtained in a scratch test under a constant load of 0.1 N, and M represents a distance by which the porous film or positive or negative electrode plate moves in a machine direction from the starting point to the point where the critical load is obtained.

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 %.

An embodiment of the present invention provides, as a nonaqueous electrolyte secondary battery separator excellent in cycle characteristic, a nonaqueous electrolyte secondary battery separator including a polyolefin porous film, wherein a ratio of a displacement amount of the nonaqueous electrolyte secondary battery separator at a 10th loading-unloading cycle to a displacement amount of the nonaqueous electrolyte secondary battery separator at a 50th loading-unloading cycle is in a range of 100% to 130%.

Method for producing nonaqueous electrolyte secondary battery separator

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 insulating porous layer usable as a member of a nonaqueous electrolyte secondary battery having an excellent cycle characteristic is provided. A nonaqueous electrolyte secondary battery insulating porous layer includes a thermoplastic resin, porosity of the nonaqueous electrolyte secondary battery insulating porous layer being not less than 25% and not more than 80%, and a ratio of a displacement amount of the nonaqueous electrolyte secondary battery insulating porous layer at tenth loading-unloading cycle to a displacement amount of the nonaqueous electrolyte secondary battery insulating porous layer at fiftieth loading-unloading cycle being not less than 100% and less than 115%.

Nonaqueous electrolyte secondary battery insulating porous layer

The present invention provides a nonaqueous electrolyte secondary battery including a porous layer which includes an organic filler in which Na element, Al element, and/or K element are contained, a total amount of the Na element, the Al element, and the K element contained falling within a certain range. The nonaqueous electrolyte secondary battery porous layer allows the nonaqueous electrolyte secondary battery to have an excellent battery capacity recovery rate after storage at a constant-voltage charge at a high temperature.

Nonaqueous electrolyte secondary battery porous layer

An insulating porous layer for a nonaqueous electrolyte secondary battery having excellent separator resistance is provided. The porous layer contains an inorganic filler and a resin, a central particle diameter of the inorganic filler is in a range of 0.1 &#x3bc;m to 11 &#x3bc;m, a BET specific surface area per unit area of the inorganic filler is not greater than 100 m/g, and the value of formula (1) is in a range of 0.10 to 0.40:[1&#x2212;T/M]&#x2003;&#x2003;(1)In formula (1), T and M respectively represent a distance by which the insulating porous layer moves in a traverse direction or a machine direction from a starting point of measurement to a point where a critical load is obtained in a scratch test under a constant load of 0.1 N.

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

A laminated porous film, including: a porous layer containing a polyolefin; and a porous layer containing a heat-resistant material and provided on at least one surface of the porous layer containing the polyolefin, the laminated porous film satisfying Formula (I) below,0.1136&#xd7;&#x3b1;+0.0819&#xd7;&#x3b2;+3.8034&#x2265;4.40&#x2003;&#x2003;(I),

Laminated porous film and non-aqueous electrolyte secondary cell

A nonaqueous secondary battery separator, disposed between a cathode and an anode, includes: a porous base material containing a polyolefin as a main component; and a porous layer containing a polyvinylidene fluoride-based resin on at least one surface of the porous base material. The separator satisfies (C)/(D)&#x2264;0.13, where (C) represents the average pore diameter (&#x3bc;m) of the porous base material, and (D) represents the porosity of the porous base material, in the porous layer after being immersed for 24 hours in an electrolyte solution having a temperature of 25&#xb0; C. in which electrolyte solution LiPFhaving a concentration of 1.0 mole per liter is dissolved in a mixed solvent containing ethyl methyl carbonate, diethyl carbonate, and ethylene carbonate at a volume ratio of 50:20:30, the resin having absorbed the electrolyte solution having a volume of 0.05 to 5.00 cmper square meter of the porous layer.

Laminated body, separator, and nonaqueous secondary battery

Provided is a laminate which is capable of ensuring a high level of safety by preventing an internal short circuit due to, for example, breakage of a non-aqueous electrolyte secondary battery while maintaining various performance capabilities of the non-aqueous electrolyte secondary battery. A laminate () includes: a porous film containing polyolefin as a main component; and a porous layer containing fine particles; the porous layer being laminated to at least one side of the porous film, in an electrical conduction test by nail penetration in which test a displacement in a thickness direction of the laminate () during a period from when a dielectric breakdown occurs in the laminate () to when the laminate () is brought into electrical conduction is measured by use of a nail () of N50 specified in JIS A 5508 and under a condition in which the nail () descends at a descending speed of 50 &#x3bc;m/min, the displacement being not less than 20 &#x3bc;m and not more than 200 &#x3bc;m.

Laminate, non-aqueous electrolyte secondary battery separator including the laminate, and non-aqueous electrolyte secondary battery including the laminate

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Osaka, Japan

Kosuke Kurakane