Nonaqueous electrolyte secondary battery and method for manufacturing same

A non-aqueous electrolyte and secondary battery technology, applied in the direction of secondary batteries, final product manufacturing, battery pack components, etc., can solve problems such as defective products, diaphragm offset, current leakage, etc., to reduce adverse conditions, suppress bias effect of displacement or damage

Inactive Publication Date: 2011-09-21
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the winding core is pulled out, the diaphragm may be shifted (displaced), and as a result, current leakage occurs in the product, resulting in product failure.

Method used

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  • Nonaqueous electrolyte secondary battery and method for manufacturing same
  • Nonaqueous electrolyte secondary battery and method for manufacturing same
  • Nonaqueous electrolyte secondary battery and method for manufacturing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0119] (1) Preparation of positive electrode 5

[0120] Add 100 parts by weight of lithium cobaltate as positive electrode active material, 2 parts by weight of acetylene black as conductive agent, and 3 parts by weight of polyvinylidene fluoride resin as binder in an appropriate amount of N-methyl-2-pyrrolidone, Kneading is performed to prepare a slurry-like mixture. The slurry was intermittently and continuously applied to both surfaces of a strip-shaped aluminum foil (thickness: 15 μm), followed by drying. Next, rolling was performed 2 to 3 times with a roll at a line pressure of 1000 kgf / cm (9.8 kN / cm) to adjust the thickness to 180 μm. The positive electrode 5 having a positive electrode active material layer on the surface was produced by cutting into a size of 57 mm in width and 620 mm in length. The active material density of the positive electrode active material layer was 3.6 g / mL.

[0121] The positive electrode lead terminal 5 a made of aluminum was ultrasonically...

Embodiment 2

[0136] In addition to using image 3 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the separator 7 having the three-layer structure shown was used as the separator.

[0137] Separator 7 was produced in the same manner as in Example 1, except that one of the two polyethylene porous films 7 b was replaced with a polypropylene porous film (thickness: 8.5 μm).

[0138] In the electrode group 14 of the non-aqueous electrolyte secondary battery, the separator 7 is arranged such that the polypropylene porous membrane 7 c faces the positive electrode 5 .

Embodiment 3

[0140] In addition to using figure 2 The non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1, except that the intermediate layer 7 a was a separator 7 of a three-layer structure including a heat-resistant porous film of polyimide as a separator. The diaphragm 7 is produced in the following steps.

[0141] After casting an NMP solution containing calcium chloride and polyamic acid which is a precursor of polyimide at a predetermined concentration, the obtained film is stretched. The stretched film was washed with water to remove calcium chloride, thereby producing a porous film. This porous membrane was heated at 300° C. to perform dehydration imidization, thereby obtaining a heat-resistant porous membrane 7 a made of polyimide having a thickness of 3 μm. The obtained heat-resistant porous membrane 7 a was sandwiched between two polyethylene porous membranes 7 b having a thickness of 8.5 μm, and rolled with a hot roll at 80° C., thereby ...

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Abstract

Disclosed is a nonaqueous electrolyte secondary battery which comprises: an electrode group in which a positive electrode that contains a long positive electrode collector and a positive electrode active material layer attached to the surface of the positive electrode collector, a negative electrode that contains a long negative electrode collector and a negative electrode active material layer attached to the surface of the negative electrode collector, and a separator for separating the positive electrode and the negative electrode from each other are wound up in a spiral form; and a nonaqueous electrolyte. The separator comprises a heat-resistant porous membrane that contains a heat-resistant resin, a first porous polyolefin membrane that covers the entire positive electrode-side surface of the heat-resistant porous membrane, and a second porous polyolefin membrane that covers the entire negative electrode-side surface of the heat-resistant porous membrane. The melting point or heat distortion temperature of the heat-resistant resin is higher than the melting point or heat distortion temperature of the polyolefin that is contained in the first and second porous polyolefin membranes. The heat-resistant porous membrane has a thickness of 1-16 [mu]m, the first porous polyolefin membrane has a thickness of 2-17 [mu]m, the second porous polyolefin membrane has a thickness of 2-17 [mu]m, and the separator has a thickness of 5-35 [mu]m.

Description

technical field [0001] The present invention relates to a non-aqueous electrolyte secondary battery capable of reducing manufacturing troubles and capable of being manufactured with high productivity. Specifically, it relates to a non-aqueous electrolyte secondary battery in which troubles caused by damage to the separator accompanying pulling out the winding core from the electrode group and the like are suppressed. Background technique [0002] A non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery has a large energy density. However, due to misuse such as external short-circuiting and overcharging, the temperature of the battery rises sharply, so sufficient safety must be ensured. In order to ensure safety, in addition to using safety mechanisms such as PTC (Positive Temperature Coefficient) elements and SU circuits (protection circuits), softening or melting properties of the resin constituting the diaphragm may also be used. [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M10/0587H01M50/414H01M50/417H01M50/423H01M50/431H01M50/451H01M50/454H01M50/457
CPCY02E60/12H01M10/0587H01M2/1686H01M10/0525H01M2/348H01M2/1646H01M2/1653H01M2/34H01M2/1613Y10T29/49112Y02E60/10H01M50/431H01M50/44H01M50/581Y02P70/50H01M50/417H01M50/454H01M50/451H01M50/457H01M50/414H01M50/423H01M10/4235
Inventor 中桐康司柴野靖幸立石沙织里山本典博
Owner PANASONIC CORP
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