Method for improving low-temperature charging and discharging performance of lithium iron phosphate battery and battery

A lithium iron phosphate battery, charge and discharge performance technology, applied in the direction of battery electrodes, secondary batteries, secondary battery repair/maintenance, etc., can solve the problem of battery cycle performance decline, poor low temperature charging performance, battery polarization impedance increase, etc. problem, to achieve the effect of improving low temperature charge and discharge performance

Pending Publication Date: 2021-01-29
DONG GUAN LONGTTECH COMPANY LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The low-temperature charging performance of the current lithium iron phosphate battery is poor. When charging below 0°C, the polarization resistance of the batte...

Method used

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  • Method for improving low-temperature charging and discharging performance of lithium iron phosphate battery and battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Under room temperature conditions, step S1: performing a sol-gel method on the lithium iron phosphate crystal for one-time nano-granulation treatment, wherein the particle size of the first-time granulation and nano-treatment of the lithium iron phosphate crystal is not greater than 100nm, wherein the sol-gel method, specifically The method of operation will be FePO 4 .4H 2 O, LiOH.H 2 O. Oxalic acid is mixed according to a certain ratio, added to deionized water, and then added to 10% glucose until a sol is formed, decompressed to remove water to form a sol, and dried in a vacuum to form a xerogel, which is pre-prepared in a nitrogen atmosphere. After burning and ball milling, nano-sized lithium iron phosphate crystals are formed; the mass ratio of graphene and primary nano-sized granulated lithium iron phosphate is 100:1 for mixing, adding hydrochloric acid dropwise to adjust to PH=6.5, and then adding hydrazine hydrate Reduction, then washed with deionized water, d...

Embodiment 2

[0044] Under room temperature conditions, step S1: performing a water / solvothermal synthesis method on the lithium iron phosphate crystal for one-time nano-granulation treatment, wherein the particle size of the first-time granulation and nano-processing lithium iron phosphate crystal is between 20-70nm, specifically The water / solvothermal synthesis method uses Na 2 HPO 4 and FeCl 3 Synthesis of FePO 4. 2H 2 O, FePO 4. 2H 2 O and CH 3 Synthesis of LiFePO by COOLi at 180°C 4,

[0045] The mass ratio of graphene and primary nano-granulated lithium iron phosphate is 60:1 to mix, dropwise add hydrochloric acid to adjust to PH=5.5, add hydrazine hydrate for reduction, then wash with deionized water, centrifuge and dry After drying, heat treatment at 600°C in a nitrogen atmosphere for 2 hours, graphene is distributed between the local surface of the primary nano-sized lithium iron phosphate crystal and the gap between the nano-sized lithium iron phosphate crystal, and then t...

Embodiment 3

[0051] Under room temperature conditions, step S1: performing a liquid-phase co-precipitation method on the lithium iron phosphate crystal for a nano-sized granulation treatment, wherein the particle size of the lithium iron phosphate crystal treated with the first-time granulation and nano-sized treatment is not greater than 100nm;

[0052] Specifically, the specific operation of liquid-phase co-precipitation method for primary nano-sized granulation is to add LiOH to (NH4) 2 Fe(SO4) 3 .6H 2 O and HPO 4 Reaction in medium to obtain co-precipitate, after filtration and washing, heat treatment is carried out under inert atmosphere, the mass ratio of graphene and primary nanosized granulated lithium iron phosphate is 70:1 for mixing, graphene is distributed in primary nanosized iron phosphate Add hydrochloric acid dropwise between the partial surface of the lithium crystal and the gap between the nano-sized lithium iron phosphate crystal to adjust the pH to 5.6, add a reducing...

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Abstract

The invention provides a method for improving the low-temperature charging and discharging performance of a lithium iron phosphate battery and the battery. Lithium iron phosphate crystals are subjected to primary nanocrystallization granulation, and graphene and lithium iron phosphate subjected to primary nanocrystallization granulation are mixed according to the mass ratio of (60-100):1; the graphene is distributed between the local surface of primary nanocrystallized lithium iron phosphate crystal and a gap of the nanocrystallized lithium iron phosphate crystal, hydrochloric acid are dropwise added to adjust to an acidic condition, a reducing agent is added, cleaning is carried out with deionized water, centrifuging, drying, and secondary nanocrystallized granulation are carried out, anddrying with inert gas is carried out, and the lithium iron phosphate partially coated with the secondary nano graphene and a binder polyvinylidene fluoride are uniformly mixed to form a positive electrode material, and the surface of a positive electrode aluminum foil is coated with the positive electrode material; the graphene is used for partially coating the modified primary nano lithium ironphosphate, so that the conductivity of the lithium iron phosphate is effectively improved.

Description

【Technical field】 [0001] The invention belongs to the technical field of lithium iron phosphate batteries, and in particular relates to a method for improving the low-temperature charging and discharging performance of lithium iron phosphate batteries and the battery. 【Background technique】 [0002] With the increase of national support for new energy and the intensive introduction of new energy policies, the "Energy Conservation and New Energy Vehicle Development Plan (2011-2020)" pointed out that by 2020, the industrialization and marketization of new energy vehicles in my country will reach the world's No. one. [0003] Lithium iron phosphate power battery has attracted people's attention due to its high safety, good high temperature characteristics, extremely long cycle life, environmental friendliness, non-toxic and harmless, and relatively low price, and has gradually become an important part of electric vehicle power batteries. choose. However, the poor electronic co...

Claims

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Application Information

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IPC IPC(8): H01M10/0525H01M4/58H01M4/587H01M4/62H01M10/0567H01M10/42
CPCH01M4/5825H01M4/587H01M4/625H01M10/0525H01M10/0567H01M10/4235Y02E60/10
Inventor 吴应强梁向龙
Owner DONG GUAN LONGTTECH COMPANY LTD
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