Separator for lithium secondary batteries, and lithium secondary battery using same

A lithium secondary battery and diaphragm technology, applied in the field of lithium secondary batteries and lithium secondary battery diaphragms, can solve the problems of small slippage of the diaphragm, damage to the diaphragm, and inability to pull out the winding core, etc., to achieve improved sliding and smoothness Pulling operation, the effect of improving pull-out performance

Inactive Publication Date: 2011-08-17
PANASONIC CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] At this time, if the slidability of the separator with respect to the winding core is small, the winding core cannot be smoothly pulled out from the electrode group, or the separator may be caught by the burrs of the electrodes, and the separator may be damaged.
Therefore, it is necessary to constantly monitor the pulling state of the winding core, resulting in an increase in manufacturing cost
When a failure occurs in the winding core extraction process, it is necessary to stop the production line and perform readjustment, reducing productivity

Method used

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  • Separator for lithium secondary batteries, and lithium secondary battery using same
  • Separator for lithium secondary batteries, and lithium secondary battery using same
  • Separator for lithium secondary batteries, and lithium secondary battery using same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0117] In the order shown below, make image 3 Diaphragm 4 shown.

[0118] (1) As the polyolefin layer 16 , a porous polyethylene film with a thickness of 20 μm was used. This film is produced by melt-extruding polyethylene and biaxially stretching the resulting molded product. The pore diameter is 0.1-1 μm, so as not to allow the active material, binder and conductive agent detached from the positive electrode 2 and the negative electrode 3 to pass through.

[0119] (2) As the heat-resistant porous layer 18 , a porous film containing polyamide was formed on one surface of the polyolefin layer 16 with a thickness of 3.5 μm. The porous membrane containing polyamide is formed by dissolving polyamide in N-methyl-2-pyrrolidone (NMP), applying the obtained solution on one side of the polyolefin layer 16 and drying it. In the solution, 200 parts by weight of an inorganic oxide (alumina having an average particle diameter of 0.013 μm) was dispersed per 100 parts by weight of polya...

Embodiment 2

[0132] As the particulate matter 22, spherical particles of perfluoroethylene propylene copolymer (FEP) having an average particle diameter of 0.2 μm were used, and the dry weight of the particulate matter 22 in the lubricating layer 14 was changed to 0.8 g / m 2 , except that, in the same manner as in Example 1, 1,000 lithium secondary batteries were produced. The surface roughness Sa of the lubricating layer 14 formed was 1.4 μm.

[0133] In the same manner as in Example 1, when the electrode group 20 was constructed, the appearance inspection of the produced electrode group 20 was carried out while observing the state of pulling out the winding core 21 . In addition, battery characteristics were evaluated in the same procedure as in Example 1.

Embodiment 3

[0135] As the particulate matter 22, SiO with an average particle diameter of 0.1 μm is used 2 spherical particles, while changing the dry weight of the particulate matter 22 in the lubricating layer 14 to 0.3g / m 2 , except that, a lithium secondary battery was produced in the same manner as in Example 1. The surface roughness Sa of the lubricating layer 14 formed was 0.2 μm.

[0136] In the same manner as in Example 1, when the electrode group 20 was constructed, the appearance inspection of the produced electrode group 20 was carried out while observing the state of pulling out the winding core 21 . In addition, battery characteristics were evaluated in the same procedure as in Example 1.

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Abstract

Disclosed is a separator (4) for lithium secondary batteries, said separator being provided with: a porous film (12) that contains a polyolefin layer (16); and a lubricant layer (14), on the surface of the porous film (12), that contains a particulate material (22). The three-dimensional surface roughness of the lubricant layer (14) is between 0.15 and 1.45 [mu]m. The particulate material (22) may be attached to the surface of the porous film (12) by electrostatic force. The porous film (12) may also be provided with a heat-resistant porous layer (18) between the polyolefin layer (16) and the lubricant layer (14). Use of a separator such as this (4) allows easy extraction of winding cores from lithium secondary batteries.

Description

technical field [0001] The present invention relates to a diaphragm for a lithium secondary battery and a lithium secondary battery using the diaphragm. More specifically, it relates to an improvement for simplifying the configuration of an electrode group of a lithium secondary battery. Background technique [0002] In recent years, lithium secondary batteries that can be repeatedly charged and discharged and have high energy density have been used as power sources for mobile devices such as personal computers and mobile phones. However, lithium secondary batteries have a high energy density, so if they are misused such as an external short circuit, the battery may react violently, and the battery temperature may rise. Therefore, safety mechanisms such as a PTC (Positive Temperature Coefficient: positive temperature characteristic) element and an SU circuit (protection circuit) are provided in the lithium secondary battery. In addition, the separator arranged between the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/18H01M10/052H01M10/0587H01M50/417H01M50/423H01M50/426H01M50/431H01M50/449H01M50/451H01M50/457H01M50/489
CPCH01M2/1686Y02E60/122H01M2/1646H01M10/052H01M2/1653Y02E60/10H01M50/431H01M50/449Y02P70/50H01M50/443H01M50/417H01M50/451H01M50/457H01M50/489H01M50/423H01M50/426H01M50/491H01M50/414
Inventor 柴野靖幸山本典博筱原泰雄渡边耕一郎
Owner PANASONIC CORP
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