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Porous polyolefine isolating film

A technology of polyolefin and separator, which is applied in the direction of electrical components, electrochemical generators, circuits, etc., can solve the problems of shrinkage or rupture of the separator, affect the safety performance of the battery, and maintain the high temperature state, so as to reduce the internal short circuit, Reduces the possibility of fire and explosion, increases the effect of polarization

Inactive Publication Date: 2010-05-05
DONGGUAN AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the battery needs to radiate heat for a long time after it is cut off, the electric vehicle battery with higher energy will generate more heat under abnormal conditions, which may cause the battery temperature to rise to a high level in a short period of time or maintain it for a long time high temperature state
At this time, the separator may shrink or rupture and may cause a short circuit between the positive and negative electrodes, generating more heat and seriously affecting the safety performance of the battery

Method used

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  • Porous polyolefine isolating film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1) Preparation of isolation membrane

[0023] Mixing and kneading a polyolefin mixture containing 5-95% by weight polyethylene A, 95-5% polyethylene B and a plasticizer (such as paraffin wax), wherein the average molecular weight of polyethylene A is 2×10 6 , the average molecular weight of polyethylene B is 1×10 5 -2×10 5 . The kneaded product is extruded into a jelly-like sheet, cooled and solidified, and then the obtained jelly-like sheet is stretched, dried and shaped to obtain the porous polyolefin isolation film of the present invention. The thickness of the isolation membrane is 35-80 μm, preferably 35-50 μm, preferably 40 μm; the porosity of the isolation membrane is 30-70%, preferably 30-50%, preferably 40%; the air permeability is 1000 seconds / 100ml , the average opening diameter is 0.001-1 μm, preferably 0.03 μm. According to the test, the cut-off temperature of the separator in Example 1 is 125°C, and the short-circuit temperature is 185°C.

[0024] It ...

Embodiment 2

[0032] 1) Preparation of isolation membrane

[0033] The preparation of the isolation film is the same as in Example 1, and the size of the isolation film is: 1500mm×54mm

[0034] 2) Preparation of positive electrode sheet

[0035] 85% by weight of lithium iron phosphate, 5% of carbon black and 5% of graphite are mixed and ground, dried and premixed to make positive electrode powder. Mix the mixed positive electrode powder with deionized water containing 5% by weight of acrylic polymer to prepare a slurry, the viscosity of which is between 6000-9000mPaS. Apply the slurry on both sides of the cable-stayed aluminum mesh, dry it at 110°C and roll it to form a positive electrode sheet with a thickness of 200 μm and a compacted density of 2.2 g / cm 3 . Finally, the positive electrode sheet is cut according to the size of 700mm×51mm.

[0036] 2) Preparation of negative electrode sheet

[0037] 93% by weight of natural graphite and deionized water containing 2% by weight of sodiu...

Embodiment 3

[0041] 1) Preparation of isolation membrane

[0042] The preparation of the isolation film is the same as in Example 1.

[0043] 2) Preparation of positive electrode sheet

[0044] Will Li 3 V 2 (PO 4 ) 3 , conductive agent and binder are evenly mixed in proportion, coated on the aluminum foil, compacted after drying, cut according to a certain size, and made into a positive electrode sheet.

[0045] 3) Preparation of negative electrode sheet

[0046] Li4Ti 5 o 12 , conductive agent and binder are mixed evenly in proportion, coated on the copper foil, dried and compacted, cut according to a certain size, and made into a negative electrode sheet.

[0047] 4) Preparation of battery

[0048] The positive electrode sheet, the negative electrode sheet and the separator are assembled, and the electrolyte is injected to obtain a lithium ion power battery. The battery evaluation results are shown in Table 1.

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Abstract

The invention discloses a porous polyolefine isolating film. The thickness of the isolating film is 35-80 mu m, the porosity is 30-70 percent, the air permeability is 100-1,000 second / 100ml and the average pore opening diameter is 0.001-1mu m. By using a lithium ion power battery of the porous polyolefine isolating film, the highest temperatures of a drift bolt and a thermal simulation are all not less than 100 DEG C, and the invention has favorable safety performance, circulating performance and charge-discharge performances.

Description

technical field [0001] The invention relates to a lithium ion battery separator, in particular to a porous polyolefin separator. Background technique [0002] As an isolation material, porous polyolefin membranes can be widely used to separate and selectively permeate various substances. For example, porous polyolefin membranes can be used as microfiltration membranes, separators in batteries, separators in capacitors, and base materials for various functional membranes. [0003] Porous polyolefin membranes are suitable as separators for lithium-ion batteries because they not only have high permeability, but also can melt polymers at a certain temperature to block the communicating pores, thereby cutting off the current to ensure the safe use of lithium-ion batteries. "Cut off" means that the pores of the porous polyolefin membrane are blocked by molten resin to increase the resistance of the membrane and intercept the flow of lithium ions. From the perspective of ensuring...

Claims

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Application Information

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IPC IPC(8): H01M2/18H01M2/16H01M10/0525H01M50/417H01M50/491
CPCY02E60/12Y02E60/122Y02E60/10
Inventor 赵丰刚朱坤庆王学泽朴美子
Owner DONGGUAN AMPEREX TECH
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