High-temperature service life testing method for lithium iron phosphate cell

A lithium iron phosphate battery, life testing technology, applied in the direction of measuring electricity, measuring devices, measuring electrical variables, etc., can solve the problems of inconvenient conversion and use, too high professional requirements, etc., to achieve high test reliability, ensure accuracy, and achieve strong effect

Active Publication Date: 2016-11-16
BST POWER SHENZHEN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method is based on a large number of mathematical models, which requires too much professionalism, and it is very inconvenient to convert and use in conventional industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The invention discloses a method for testing the high-temperature life of a lithium iron phosphate battery. The 4-year cycle life of a lithium iron phosphate battery that has been formed is tested according to the following method:

[0028] (a) Charging: 0.1C constant current charging to 3.65V at a temperature of 55±2°C;

[0029] (b) Float charge: at a temperature of 55±2°C, when the battery voltage is lower than 3.45V, charge the battery at a constant current of 0.1C to 3.65V, then stop, and then keep it below 3.45V to start the 0.1C continuous charging state, up to 30 days;

[0030] (c) Discharge: discharge at 0.25C to 2.5V at a temperature of 55±2°C;

[0031] (a), (b), and (c) are one cycle, and the qualified standard is that the battery capacity is greater than 75% of the nominal capacity after 48 cycles.

[0032] In this embodiment, the high temperature condition is provided by a constant temperature and humidity oven; the lithium iron phosphate battery is connec...

Embodiment 2

[0034] The invention discloses a high-temperature life test method of a lithium iron phosphate battery. The lithium iron phosphate battery that has been formed is taken, and its 1-year cycle life is tested according to the following method:

[0035] (a) Charging: 0.1C constant current charging to 3.65V at a temperature of 70±2°C;

[0036] (b) Float charge: at a temperature of 70±2°C, when the battery voltage is lower than 3.45V, charge the battery at a constant current of 0.1C to 3.65V, then stop, and then keep it below 3.45V to start the 0.1C continuous charging state, until 120 days;

[0037] (c) Discharge: discharge at 0.25C to 2.5V at a temperature of 70±2°C;

[0038] (a), (b), and (c) are a cycle, and step (d) is executed after 3 cycles:

[0039] (d) At a temperature of 55±2°C, charge to 3.65V with a constant current of 0.1C, then discharge to 2.5V with a constant current of 0.25C, and cycle 3 times. The qualified standard is that the discharge capacity is greater than ...

Embodiment 3

[0042] The invention discloses a method for testing the high-temperature life of a lithium iron phosphate battery. The lithium iron phosphate battery that has been formed is taken to test its 4-year cycle life according to the following method:

[0043] (a) Charging: 0.1C constant current charging to 3.65V at a temperature of 25±2°C;

[0044] (b) Float charge: at a temperature of 65±2°C, when the battery voltage is lower than 3.45V, charge the battery at a constant current of 0.1C to 3.65V, then stop, and then keep it below 3.45V to start the 0.1C continuous charging state, up to 30 days;

[0045] (c) Discharge: discharge at 0.25C to 2.5V at a temperature of 25±2°C;

[0046] (a), (b) and (c) are a cycle, and step (d) is executed after 18 cycles:

[0047] (d) At a temperature of 55±2°C, charge to 3.65V with a constant current of 0.1C, then discharge to 2.5V with a constant current of 0.25C, and cycle 3 times. The qualified standard is that the discharge capacity is greater than...

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PUM

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Abstract

The invention discloses a high-temperature service life testing method for a lithium iron phosphate cell, and the method comprises the steps: taking the lithium iron phosphate cell after formation, fully charging the lithium iron phosphate cell with a small current under set temperature, carrying out the small-current floating charge of the lithium iron phosphate cell for set time under the high-temperature condition and discharging the lithium iron phosphate cell under the set temperature after floating charging, wherein the above steps form one cycle; measuring the capacity of the lithium iron phosphate cell for three times under the set temperature after a plurality of cycles; comparing the capacities with 75% of the nominal capacity, and judging whether the lithium iron phosphate cell is qualified or not. The method is high in testing accuracy, is short in testing period, is convenient for testing, and is high in reference performance.

Description

technical field [0001] The invention relates to the technical field of testing lithium iron phosphate batteries, in particular to a high temperature life testing method for lithium iron phosphate batteries. Background technique [0002] Lithium-ion batteries are widely used in mobile digital products, and have also been used in electric vehicles as energy storage systems in recent years. The service life is an important index to measure the performance of the battery. At present, the life test method widely used in the research and development, inspection and selection of lithium-ion batteries is to conduct cycle tests under certain working conditions. Currently, the method used to test the cycle life of lithium-ion batteries The standards generally refer to the provisions of the two current standards in my country: QC / T743-2006 lithium-ion batteries for electric vehicles and QB / T2502-2000 general specifications for lithium-ion batteries. There are currently two main methods ...

Claims

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Application Information

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IPC IPC(8): G01R31/36
CPCG01R31/385
Inventor 范海满谢玉强朱杰邱恋东
Owner BST POWER SHENZHEN
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