Composite diaphragm, preparation method and battery thereof

A technology of composite diaphragm and heat insulation layer, which is applied in the direction of secondary batteries, battery pack components, circuits, etc., can solve the problems of poor safety performance of the diaphragm, and achieve the effect of enhancing high-temperature safety performance

Active Publication Date: 2014-01-29
SHANGHAI BYD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is that the separator in the prior art has poor safety performance at high temperature, so as to provide a battery separator with good safety

Method used

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  • Composite diaphragm, preparation method and battery thereof
  • Composite diaphragm, preparation method and battery thereof

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preparation example Construction

[0028] A kind of preparation method of above-mentioned composite diaphragm, it comprises the steps:

[0029] (1) Dispersing the nano-inorganic oxide in a dispersant to make a slurry, and then coating the slurry on both upper and lower surfaces of the base layer to form a thermal insulation layer;

[0030] (2) dissolving the polymer in a solvent, adding a plasticizer and stirring evenly to make a polymer coating solution; coating the polymer coating solution on the heat-insulating layer described in step (1);

[0031] (3) The product of step (2) is vacuum-dried at 50-90°C.

[0032] Wherein, the dispersant in step (1) is well known to those skilled in the art, as long as it has a low boiling point and is volatile, such as acetone, toluene and the like.

[0033] The dosage of the dispersant per gram of nano inorganic oxide is preferably 100-200 grams.

[0034] The preferred operation of step (1) is: adding the nano-inorganic oxide into the dispersant and stirring, controlling t...

Embodiment 1

[0048] ① Take polypropylene microporous membrane as the base layer, with a thickness of 16 μm and a porosity of 38%.

[0049] 10gAl 2 o 3 (average particle size 50nm) was added into 1500g of dispersant acetone and stirred, the rotation speed was controlled at 1200r / min, and stirred for 1h. Then disperse with ultrasonic wave, control the power of 100W, and continue ultrasonication for 30min; finally obtain the slurry. Spray the slurry evenly on the upper and lower sides of the base.

[0050] ② Take 30g of hexafluoroethylene-vinylidene fluoride copolymer (HFP-PVDF) (number average molecular weight is 5×10 5 ) into 2500g solvent acetone and stir until it is completely dissolved, control the speed at 1200r / min, stir for 2h, and the temperature of dissolution is 60°C; then add 40g of plasticizer dimethyl carbonate (DMC) to the above solution, and stir for 30min , the rotating speed is 1200r / min, forming a coating solution. Spray the coating solution on the outer surfaces of th...

Embodiment 2

[0054] ① Take polyethylene microporous membrane as the base layer, its thickness is 16μm, and the porosity is 38%.

[0055] 10gSiO 2 (average particle size 50nm) was added into 1500g of dispersant acetone and stirred, the rotation speed was controlled at 1200r / min, and stirred for 1h. Then disperse with ultrasonic wave, control the power of 100W, and continue ultrasonication for 30min; finally obtain the slurry. Spray the slurry evenly on the upper and lower sides of the base.

[0056] ② 30g polymer hexafluoroethylene-vinylidene fluoride copolymer (HFP-PVDF) (number average molecular weight is 5×10 5 ) into 2500g of acetone and stir until completely dissolved, control the speed at 1200r / min, stir for 2h, and the temperature of dissolution is 60°C; then add 40g of dimethyl carbonate (DMC) to the above solution, stir for 30min, and the speed is 1200r / min to form a coating solution. Spray the coating solution on the outer surfaces of the two layers of insulation.

[0057] ③...

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Abstract

The invention belongs to lithium ion battery technical field, and specifically discloses a composite diaphragm. The composite diaphragm from the top to the bottom successively comprises a porous polymer coating, a thermal insulation layer, a base layer, a thermal insulation layer and a porous polymer coating; wherein the thermal insulation layer is a nanometer inorganic oxide layer. The invention also provides a preparation method of the composite diaphragm, which comprises the steps: dispersing the nanometer inorganic oxide into dispersant to prepare slurry, then coating the slurry on the upper and lower surfaces of the base layer, to prepare the thermal insulation layer; then dissolving polymer in solvent, adding plasticizer and stirring well, preparing polymer coating liquid and coating the liquid on the thermal insulation layer; and finally drying under the temperature of 50 to 90 DEG. The invention also provides a battery that uses the composite diaphragm. The composite diaphragm of the present invention has good heat insulation performance and good high temperature safety performance. The preparation method is capable of simple process and is easy for industrial production.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a composite diaphragm, a preparation method thereof and a battery. Background technique [0002] Lithium-ion batteries are usually composed of a positive electrode, a negative electrode, a separator and an electrolyte. The separator is used as a barrier between the positive and negative electrodes. It has good insulation for electrons and good passability for ions, which is an important part of the battery. component. In actual use, the separator must adapt to the changes in the battery's positive and negative electrodes and electrolytes during charge and discharge. In addition, the performance of the separator also determines the interface structure of the battery and the internal resistance of the battery, which in turn affects the key performance of the battery such as capacity, cycle performance, and charge-discharge current density. [0003] Durin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 谢皎董谦潘虹谷潘福中
Owner SHANGHAI BYD
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