Negative electrode slurry of lithium ion battery, positive electrode of lithium ion battery prepared by slurry and battery

A lithium-ion battery and negative electrode slurry technology, applied in battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve problems such as uneven pore distribution, low porosity, poor battery rate and low temperature performance

Active Publication Date: 2014-01-15
BYD CO LTD
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the problems that the negative electrode prepared by the negative electrode slurry in the prior art has low porosity and uneven pore distribution when the energy density is ensured, especially the phenomenon of closed pores in the surface layer is serious, and the battery rate and low-temperature performance of the prepared battery are poor, the invention provides an energy-efficient battery. Lithium-ion battery negative electrode slurry for preparing negative electrode with high porosity, especially uniform pore distribution, and lithium-ion battery negative electrode and battery prepared by using the negative electrode slurry

Method used

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  • Negative electrode slurry of lithium ion battery, positive electrode of lithium ion battery prepared by slurry and battery
  • Negative electrode slurry of lithium ion battery, positive electrode of lithium ion battery prepared by slurry and battery
  • Negative electrode slurry of lithium ion battery, positive electrode of lithium ion battery prepared by slurry and battery

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preparation example Construction

[0031] The preparation of the negative electrode may also include other steps, for example, after-treatment of the cut piece, which is well known to those skilled in the art. After heat treatment, it is cut according to the size of the negative electrode required by the prepared battery to obtain the negative electrode sheet.

[0032] Preferably, the thickness of the negative electrode sheet prepared by the present invention is 90~150um, and the compacted density is 1.20~1.45g / cm 3 .

[0033] The present invention also provides a lithium-ion battery, comprising a battery case and an electrode group and an electrolyte sealed in the battery case; the electrode group includes a positive pole, a negative pole, and a diaphragm between the positive pole and the negative pole, wherein, The negative electrode is the above-mentioned negative electrode of the lithium ion battery.

[0034] The present invention has no special requirements for the preparation method of the lithium-ion ba...

Embodiment 1

[0047] This embodiment is used to illustrate the negative electrode slurry, lithium ion battery negative electrode and lithium ion battery of the present invention.

[0048] (1) Preparation of negative electrode slurry for lithium-ion batteries

[0049] Get 100 parts by weight of graphite, 130 parts by weight of deionized water, 2 parts by weight of carbon black, 2 parts by weight of carboxymethyl cellulose (CMC), 4 parts by weight of styrene-butadiene rubber (SBR), pore-forming agent azodicarbonamide ( Particle size 0.5~2.5um, decomposition temperature 110°C, residual ash content after decomposition not higher than 0.2%) 3 parts by weight.

[0050] Stir CMC and deionized water for 3 hours under the condition that the vacuum degree is less than -0.08MPa to obtain the CMC aqueous solution, then add carbon black, SBR, graphite, and pore-forming agent to the CMC aqueous solution, and then the vacuum degree is less than -0.08MPa. The mixture was fully stirred for 7 hours to obtai...

Embodiment 2

[0058] Negative electrode slurry, negative electrode, positive electrode and lithium ion battery were prepared according to the method of Example 1, the difference was that the amount of pore-forming agent in step (1) was 2 parts by weight, and the negative electrode slurry was prepared with a thickness of 120um, compacted The density is 1.32g / cm 3 , a negative electrode sheet with a porosity of 38.95%, and finally sliced ​​to obtain a negative electrode sheet sample S2 of a lithium-ion battery with length×width×thickness=491mm×43.5mm×120μm. The rest of the steps are the same, and the 053450 lithium ion battery S22 is obtained.

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Abstract

The invention provides negative electrode slurry of a lithium ion battery, a positive electrode of the lithium ion battery prepared by using the slurry, and the battery. The negative electrode slurry comprises a negative-electrode active material, a bonding agent, a solvent and a pore-forming agent, wherein the pore-forming agent is selected from one or more in azo-compound and / or sulfonylhydrazine compound. The slurry, the positive electrode and the battery have the advantages that under the condition of guaranteeing no reduction of the compaction density of a negative electrode piece, the porosity of the electrode piece can be increased, the uniformity of pore distribution is increased, the effective area of a liquid phase for conducting lithium ions is improved, the high energy density of the battery is guaranteed, simultaneously the rate capability and the low-temperature performance of the battery are improved and simultaneously the capacity is also improved.

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode slurry, a lithium ion battery negative electrode and a lithium ion battery prepared by using the negative electrode slurry of the invention. Background technique [0002] Lithium-ion batteries are currently widely used secondary batteries, which have the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, and no pollution. Widely used in electric tools, electric vehicles and other fields, it not only requires high energy density, long cycle life, good consistency, good safety, low cost, etc., but also requires high specific power and excellent high rate charge and discharge performance. Therefore, it is of great significance to improve the rate charge and discharge performance of lithium-ion batteries for their popularization and application. [0003] The diffusion and transport of lithium ions in the negative electrode sheet is an importa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/13H01M10/0525
CPCH01M4/133H01M4/62H01M10/0525Y02E60/10H01M4/02H01M4/0402H01M4/366H01M10/054H01M10/0562
Inventor 沈益顺颜海鹏张学全张欣欣
Owner BYD CO LTD
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