Nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-2019190056-A1
Application number	US-201816224157-A
Country	US
Kind code	A1
Filing date	Dec 18, 2018
Priority date	Dec 19, 2017
Publication date	Jun 20, 2019
Grant date	—

Abstract

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 α-form polyvinylidene fluoride-based resin.

First claim

1 . A nonaqueous electrolyte secondary battery comprising:
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 of not less than 1 nF and not more than 1000 nF per measurement area of 900 mm 2 ; and a negative electrode plate having a capacitance of not less than 4 nF and not more than 8500 nF per measurement area of 900 mm 2 , the polyolefin porous film having a parameter X of not more than 20, the parameter X being calculated in accordance with the following expression:
X= 100×|MD tan δ−TD tan δ|/{(MD tan δ+TD tan δ)/2}

where MD tan δ represents a tan δ in a machine direction and TD tan δ represents a tan δ in a transverse direction, the tan δ in the machine direction and the tan δ in the transverse direction each being obtained through a viscoelasticity measurement performed at a frequency of 10 Hz and at a temperature of 90° C., the porous layer being provided between the nonaqueous electrolyte secondary battery separator and at least one of the positive electrode plate and the negative electrode plate, the polyvinylidene fluoride-based resin contained in the porous layer containing an α-form polyvinylidene fluoride-based resin and a β-form polyvinylidene fluoride-based resin, a content of the α-form polyvinylidene fluoride-based resin being not less than 35.0 mol % with respect to 100 mol % of a total content of the α-form polyvinylidene fluoride-based resin and the β-form polyvinylidene fluoride-based resin in the polyvinylidene fluoride-based resin, the content of the α-form polyvinylidene fluoride-based resin being calculated by (a) waveform separation of (α/2) observed at around −78 ppm in a 19 F-NMR spectrum obtained from the porous layer and (b) waveform separation of {(α/2)+3} observed at around −95 ppm in the 19 F-NMR spectrum obtained from the porous layer.

2 . The nonaqueous electrolyte secondary battery as set forth in claim 1 , wherein the positive electrode plate contains a transition metal oxide.

3 . The nonaqueous electrolyte secondary battery as set forth in claim 1 , wherein the negative electrode plate contains graphite.

4 . The nonaqueous electrolyte secondary battery as set forth in claim 1 , further comprising:
another porous layer which is provided between (i) the nonaqueous electrolyte secondary battery separator and (ii) at least one of the positive electrode plate and the negative electrode plate.

5 . The nonaqueous electrolyte secondary battery as set forth in claim 4 , wherein the another porous layer contains at least one kind of resin selected from the group consisting of polyolefins, (meth)acrylate-based resins, fluorine-containing resins (excluding polyvinylidene fluoride-based resins), polyamide-based resins, polyester-based resins and water-soluble polymers.

6 . The nonaqueous electrolyte secondary battery as set forth in claim 5 , wherein the polyamide-based resin is an aramid resin.

Assignees

• Sumitomo Chemical Co

Inventors

• Arise Ichiro
• Ogata Toshihiko
• Murakami Chikara
• Hashiwaki Hiroki

Classifications

• H01M50/457

  comprising three or more layers · CPC title

• H01M10/05 Primary

  Accumulators with non-aqueous electrolyte (H01M10/39 takes precedence) · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title