Pole piece, preparation method thereof and battery

A pole piece and positive pole piece technology, which is applied in the field of pole piece and its preparation, can solve the problems of different pole piece current density, uneven pole piece thickness, and increased battery resistance.

Inactive Publication Date: 2021-05-28
EVE ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the current pole piece preparation process, the main problems are: 1. The internal pores of the pole piece are unevenly distributed, resulting in different current densities in different regions of the pole piece during the battery discharge process, and the discharge capacity of the battery cannot be maximized.
2. The depth of discharge in different regions of the pole piece is different, and the expansion situation is also different. During the discharge process, the battery is prone to increase in battery resistance due to the separation of the active material from the current collector (powder drop), and the final pulse capability drops rapidly; serious Internal short circuit of the battery may occur due to local powder falling
[0007] However, the above methods all have the problems of uneven thickness of the pole piece and poor discharge capacity of large current.

Method used

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  • Pole piece, preparation method thereof and battery
  • Pole piece, preparation method thereof and battery
  • Pole piece, preparation method thereof and battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] The present embodiment is prepared according to the following method:

[0060] (1) 78wt% LiFePO 4 Fully mix with 2wt% conductive carbon, then fully mix with 3% polytetrafluoroethylene binder, 17wt% ethanol / water (1 / 2) mixed solvent, use a high-speed granulator to mix and granulate at a speed of 1000rpm for 5min, Prepare mixed particles;

[0061] (2) The mixed particles described in step (1) are used with a three-roll film laminator (0.1 mm between roll 1 and roll 2, and 0.08 mm between roll 2 and roll 3) at a temperature of 25 ° C with a speed of 3 r / min. The aluminum foil of the current collector is formed into a membrane, and then baked in an oven at 120° C. for 8 hours, and then cut into positive electrodes after baking.

[0062] The schematic flow chart of the preparation method of this embodiment is as follows figure 1 shown.

[0063] The schematic diagram of the laminating machine of this embodiment is as figure 2 As shown, the roll 1 and roll 2 of the clamp...

Embodiment 2

[0066] The present embodiment is prepared according to the following method:

[0067] (1) with the step 1 of embodiment 1

[0068] (2) The mixed particles described in step (1) are used in a four-roll laminating machine (the distance between the roller 1 and the roller 2 and the roller 3 and the roller 4 is 0.1 mm, and the distance between the roller 2 and the roller 3 is 0.1 mm), at 25 °C at a roller speed of 3r / min to form a membrane with the aluminum foil of the current collector, and then bake in an oven at 120 °C for 8 hours, and then bake and cut to obtain the positive electrode sheet.

[0069] The schematic diagram of the laminating machine of this embodiment is as image 3 As shown, roll 1 and roll 2 of the clamping machine pre-press the mixed particles, roll 3 and roll 4 also pre-press the mixed particles, and roll 2 and roll 3 combine the pre-pressed mixed particles with the current collector Co-membrane.

[0070] The test results of the positive electrode sheet p...

Embodiment 3

[0072] The present embodiment is prepared according to the following method:

[0073] (1) Fully mix 95wt% lithium iron phosphate and 2.5wt% conductive carbon, then fully mix with 2.5% polytetrafluoroethylene binder, use a high-speed granulator to mix and granulate at a speed of 200rpm for 1min, and prepare a mixed particles;

[0074] (2) Use the same four-roll mold clamping machine as in Example 2 to form the positive electrode sheet with the aluminum foil of the current collector at a temperature of 15 ° C at a temperature of 15 ° C, and then place it in a 200 ° C Bake in an oven for 28 hours to obtain a positive electrode sheet.

[0075] The test results of the positive electrode sheet prepared in this example are shown in Table 1.

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Abstract

The invention provides a pole piece, a preparation method thereof and a battery. The preparation method comprises the following steps: (1) an active substance, a conductive agent, a solvent and a binder are mixed and granulatedto obtain mixed particles; and (2) the mixed particles obtained in the step (1) and a current collector are subjected to film combining in a film combining machine, the pole piece is obtained, and the number of rollers of the film combining machine is three or more than three. According to the preparation method provided by the invention, the pole piece can obtain relatively good porosity under the condition of keeping relatively high compaction density, so that the battery has relatively good discharge capacity, especially the discharge capacity under relatively high current and relatively low temperature conditions, and meanwhile, the thickness consistency of the pole piece is good. In addition, the method is simple in manufacturing process, high in automation level and capable of achieving one-process output from feeding to pole piece forming.

Description

technical field [0001] The invention belongs to the technical field of batteries, and relates to a pole piece, a preparation method thereof and a battery. Background technique [0002] With the advancement of science and technology, lithium batteries are more and more widely used in life; from small household appliances to new energy vehicles to large energy storage, it can be found in various fields. At present, the mainstream positive electrode systems include LCO, NCM, NCA, LFP, LMO, etc., and the negative electrode systems include artificial graphite, natural graphite, LTO, Si-C composite, artificial and natural composite systems, etc., and their structures are diverse, including square, cylindrical, etc. And button lithium battery; according to the outsourcing material, it is divided into aluminum shell, steel shell and soft pack lithium battery. Square aluminum shell batteries are widely used in lithium power and energy storage because of their simple structure, high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/13H01M4/139H01M10/0525
CPCH01M4/0435H01M4/13H01M4/139H01M10/0525Y02P70/50Y02E60/10H01M4/0404H01M4/505H01M4/525H01M4/5825H01M4/587H01M4/386H01M4/364H01M4/622H01M4/623H01M4/131H01M4/1391H01M4/1393H01M4/133H01M4/134H01M4/136H01M4/1395H01M4/1397
Inventor 朱亮赵瑞瑞邱欣斌祝媛刘建华刘金成
Owner EVE ENERGY CO LTD
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