Method for increasing cycle life of lithium ion battery based on thermal conductivity

A lithium-ion battery, cycle life technology, used in battery electrodes, secondary battery repair/maintenance, circuits, etc., can solve the problems of uneven current distribution, large size, and uneven battery temperature, and reduce the internal temperature of the battery. Uneven, simple and easy to implement, the effect of improving the overall performance

Inactive Publication Date: 2016-08-03
RISESUN MENGGULI NEW ENERGY SCIENCE & TECHNOLOGY CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] After the lithium-ion battery is enlarged, it has high capacity and large size, and its heat dissipation is relatively weak compared with heat generation. If the heat generated by the battery during operation cannot be conducted in a timely and even manner inside the battery, the temperature of the battery will be uneven. Taking lithium-ion pouch battery as an example, in the positive pole piece inside the lithium-ion battery, if the thermal conductivity of the battery is poor, the temperature of the battery pole piece is uneven, and local heat accumulation leads to overheating, which will accelerate the failure of the electrochemical performance of the pole piece in this area. , resulting in uneven distribution of current through the pole piece, which in turn makes the polarization between different regions of the whole pole piece larger, seriously affecting the overall service life of the battery

Method used

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  • Method for increasing cycle life of lithium ion battery based on thermal conductivity
  • Method for increasing cycle life of lithium ion battery based on thermal conductivity
  • Method for increasing cycle life of lithium ion battery based on thermal conductivity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Weigh lithium manganate LiMn 2 o 4 915g, PVDF45g, conductive carbon black SP and conductive graphite KS15 20g in total, carbon nanotubes (CNTS) 20g, put the weighed material in a high-temperature vacuum oven at 100°C for overnight baking, and set aside.

[0029] 2) Add PVDF to the solvent NMP (Nitromethylpyrrolidone) for gluing.

[0030] 3) Put the materials dried in 1) and the glue beaten in 2) into a planetary vacuum mixer, and carry out vacuum stirring for 3-5 hours to form a uniform slurry.

[0031] 4) Sieve the uniformly mixed slurry, and measure the slurry fineness and viscosity.

[0032] 5) The slurry is coated on the front and back sides on the coating machine.

[0033] 6) Trim and remove the edges of the coated pole pieces, and place them in a vacuum oven for baking.

[0034] 7) Roll the baked pole piece, and then perform final cutting according to the design size of the lithium-ion battery flexible package.

[0035] 8) Take a sample of the cut positive...

Embodiment 2

[0040] 1) Weigh lithium manganate LiMn 2 o 4 915g, PVDF45g, conductive carbon black SP and conductive graphite KS15 total 20g, graphene 20g, bake the weighed material in a high-temperature vacuum oven at 100°C for one night, and set aside.

[0041] 2~7) with embodiment 1.

[0042] 8) Take a sample of the cut positive pole piece for SEM scanning test and electronic conductivity test, see figure 2 .

[0043] 9) With embodiment 1.

[0044] 10) In order to prove the improvement of thermal conductivity, a thermal imaging test was carried out on the complete battery, as shown in Figure 3. At the same time, an electrochemical high-temperature cycle performance test was also carried out to prove that the addition of the thermal conductivity material improved the cycle life.

[0045] pass figure 2 It can be seen that after adding graphene, the conductivity is greatly improved compared with the common positive electrode sheet without adding the same ratio, which can reduce the ohmi...

Embodiment 3

[0048] 1) Weigh lithium manganate LiMn 2 o 4 915g, PVDF45g, 20g of conductive carbon black SP and conductive graphite KS15, 10g of graphene, 10g of carbon nanotubes (CNTS), put the weighed materials in a high-temperature vacuum oven at 100°C for one night and set aside.

[0049] 2~9) with embodiment 1.

[0050] 10) In order to prove the improvement of thermal conductivity, the complete battery was subjected to a thermal imaging test, and at the same time, an electrochemical high-temperature cycle performance test was also performed, see Figure 4 , to prove that the addition of the thermally conductive material improves the cycle life.

[0051] pass Figure 4 It can be seen that the charge-discharge cycle test of the lithium manganate battery at a rate of 55°C 1C, the cycle life of the battery with the addition of the thermal conductive agent combination (graphene and CNTS) is significantly better than that of the ordinary lithium manganate battery without addition.

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Abstract

The invention discloses a method for increasing cycle life of a lithium ion battery by increasing thermal conductivity of an electrode of the lithium ion battery. The method comprises the following steps: a heat conduction material having superhigh electric conduction and thermal conductivity is added in a positive pole piece of the lithium ion battery, and the flexibly packaged lithium ion battery is made. The heat conduction material is graphene or a carbon fiber material; the carbon fiber material comprises a hollow carbon nanotube and solid carbon nano fiber. The graphene and the carbon fiber material have excellent thermal conductivity, thereby, addition of graphene and the carbon fiber material can rapidly, uniformly and fully transmit heat generated during a charge and discharge process of the battery, uneven temperature in the batter due to accumulation of local heat is reduced, therefore, area degradation of the lithium ion battery is improved, the charge and discharge cycle efficiency of the battery is improved, and cycle life and security are increased.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a process for improving the cycle life of lithium-ion batteries by improving the thermal conductivity of the batteries. Background technique [0002] Due to high working voltage, small size, light weight, high energy, no memory effect, no pollution, and small self-discharge, lithium-ion batteries are used as a The ideal high-efficiency green energy has received special attention and has been recognized by various automobile manufacturers and battery manufacturers, and is regarded as an ideal energy for development in the 21st century. [0003] Although lithium-ion batteries have certain advantages in replacing traditional batteries as power sources for electric vehicles, hybrid electric vehicles, electric bicycles, and electric tools, lithium-ion batteries are working, as the number of charge and discharge increases and the battery ages, The internal resistance wil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/62H01M4/131H01M10/42
CPCY02E60/10
Inventor 吴宁宁刘建红孙召琴
Owner RISESUN MENGGULI NEW ENERGY SCIENCE & TECHNOLOGY CO LTD
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