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A lithium iron phosphate battery matching method for reducing the discharge voltage difference between series battery packs

A technology of lithium iron phosphate batteries and series battery packs, which is applied in secondary battery charging/discharging, secondary battery repair/maintenance, and electrical measurement, and can solve problems such as high cost, small number of batteries, and enhanced inconsistency between batteries. problem, to achieve the effect of improving consistency and reducing the discharge voltage difference

Active Publication Date: 2018-02-06
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] There have been extensive studies on battery matching methods. In addition to single-parameter matching such as voltage, internal resistance, and capacity, multi-parameter and dynamic matching methods have also been studied in depth. However, due to the high cost, the parameter characterization method is single. , the practical applicability is not strong, and the number of batteries used is small, which is quite different from the actual situation of the vehicle battery
[0004] At present, the method of grouping according to parameters such as capacity, internal resistance, voltage, etc. is still a static grouping in essence, which can only reflect the situation of the battery in a static state, while the power battery pack is in the process of operation, and the above parameters are constantly changing. In the dynamic process, the matching parameters of the static process that tended to be consistent have changed greatly under the actual conditions of battery charging and discharging. The inconsistency between batteries increases with the increase in the number of charging and discharging, seriously affecting battery pack life

Method used

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  • A lithium iron phosphate battery matching method for reducing the discharge voltage difference between series battery packs
  • A lithium iron phosphate battery matching method for reducing the discharge voltage difference between series battery packs

Examples

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Effect test

Embodiment 1

[0026] A lithium iron phosphate battery matching method for reducing the discharge voltage difference between battery packs in series, comprising the following steps:

[0027] (1) Select a battery with a rated capacity of 13Ah, discharge it to an empty battery with a current of 0.05C, and cut off the current at 200mA;

[0028] (2) Aging at 40°C for 10 days, select 5000 batteries according to the voltage range of 2.5V-3.05V;

[0029] (3) Divide the selected battery with a current of 0.5C, the steps are charge-discharge, and the final cut-off current is 200mA;

[0030] (4) Match the batteries according to the relevant series and parallel requirements, make the above 5,000 batteries into a battery pack for 10 electric vehicles, and require the average discharge voltage difference between all series connected battery packs of each electric vehicle to be ≤ 100mV , Discharge capacity difference <500mAh.

[0031] Connect the above-mentioned assembled battery packs in series to cond...

Embodiment 2

[0033] A lithium iron phosphate battery matching method for reducing the discharge voltage difference between battery packs in series, comprising the following steps:

[0034] (1) Select a battery with a rated capacity of 9Ah, put the current at 0.5C to an empty battery, and cut off the current at 200mA.

[0035] (2) Aging at 60°C for 4 days, select 5000 batteries according to the voltage range of 2.75V-2.95V.

[0036] (3) Divide the selected battery with a current of 0.1C, the steps are charge-discharge, and the final cut-off current is 200mA.

[0037] (4) Match the batteries according to the relevant series-parallel requirements, screen the above 5,000 batteries to form a battery pack for 10 electric vehicles, and require the average discharge voltage range between all series-connected battery packs for each electric vehicle ≤50mV, discharge capacity difference <300mAh.

[0038] Connect the above-mentioned assembled battery packs in series to conduct electrical performance...

Embodiment 3

[0041] A lithium iron phosphate battery matching method for reducing the discharge voltage difference between battery packs in series, comprising the following steps:

[0042] (1) Select a battery with a rated capacity of 20Ah, discharge it to an empty battery with a current of 0.33C, and cut off the current at 200mA.

[0043] (2) Aging at 55°C for 4 days, select 6500 batteries according to the voltage range of 2.5V-2.95V.

[0044] (3) Divide the selected battery with a current of 0.33C, the steps are charge-discharge, and the final cut-off current is 200mA.

[0045] (4) Match the batteries according to the relevant series-parallel requirements, screen the above 6,500 batteries to form a battery pack for 10 electric vehicles, and require the average discharge voltage difference between all series-connected battery packs for each electric vehicle ≤100mV, discharge capacity difference <800mAh.

[0046] Connect the above-mentioned assembled battery packs in series to conduct el...

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Abstract

The invention discloses a lithium iron phosphate battery assembling method capable of reducing discharge voltage difference between cascade battery packs. After an empty battery is aged at high temperature, the batteries are grouped in different levels by utilizing a discharge average voltage and discharge capacity in the capacity dividing process, so that the discharge voltage difference between electric car battery packs is remarkably reduced, the consistency of the battery packs in the charge / discharge process is improved, and the effect for assembling the battery packs with small cascade-parallel number is remarkable.

Description

technical field [0001] The invention relates to a grouping method for lithium iron phosphate batteries used in electric vehicles, in particular to a method for grouping lithium iron phosphate batteries used for reducing the discharge voltage difference between series-connected battery groups with a relatively low number of series and parallel connections. Background technique [0002] Lithium-ion power batteries have been gradually applied to the electric vehicle industry. As the core component of electric vehicles, the consistency of power battery packs determines the service life of electric vehicles. As the power source of electric vehicles, the power battery pack is generally used by combining hundreds or thousands of single cells in a certain series-parallel mode to form a battery module. In order to improve the performance of the power battery pack, in addition to improving the manufacturing process of the single battery In addition, appropriate assembly processes and ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/42H01M10/44G01R31/36
CPCG01R31/36H01M10/42H01M10/44Y02E60/10
Inventor 杨乃昆宫璐
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY