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Method for inferring internal DC resistance of lithium ion battery

A lithium-ion battery, DC internal resistance technology, applied in the direction of measuring resistance/reactance/impedance, measuring device, measuring electrical variables, etc., can solve the problems of electrode damage, loss of battery life, etc., to avoid damage, save energy and resources , The effect of high detection speed and accuracy

Inactive Publication Date: 2015-02-04
TIANJIN LISHEN BATTERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the battery passes a large current, the electrodes inside the battery will be polarized, which will cause some damage to the electrodes inside the battery. Therefore, repeated DC internal resistance tests on the battery will damage the life of the battery.

Method used

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  • Method for inferring internal DC resistance of lithium ion battery
  • Method for inferring internal DC resistance of lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0027] Select the lithium-ion battery 1# with a nominal capacity of 16.5Ah (that is, 1C=16.5A). Carry out 1C charge and discharge cycle under normal temperature conditions, test process:

[0028] 1. 1C constant current charging to the cut-off voltage of 3.65V, and then constant voltage charging until the current decreases to 0.05C (ie 0.825A);

[0029] 2. Sleep for 10 minutes;

[0030] 3. Use 1C current to discharge to 2.0V, and the discharge ends;

[0031] 4. Sleep for 10 minutes.

[0032] Repeat steps 1-4 for multiple cycles.

[0033] In the middle of the cycle test process of the battery of this embodiment, after the 0th cycle (i.e. before the cycle), 500 times, 1000 times, 1900 times, 2200 times, 2500 times... under normal temperature conditions, measure and record The AC internal resistance IR of the battery at that time 1 and DC internal resistance DCIR 1 .

[0034] Take the X-axis as the number of cycles, and the Y-axis as the internal resistance value, make a sc...

Embodiment 2

[0045] The battery experiment steps in this embodiment are as follows:

[0046] 1. Take two batteries with a nominal capacity of 20Ah (that is, 1C=20A), and mark them as 1# and 2# respectively. Carry out 1C charge and discharge cycle under normal temperature conditions, test process:

[0047]① 1C constant current charging to the cut-off voltage of 3.65V, and then constant voltage charging until the current decreases to 0.05C (ie 1A);

[0048] ②Sleep for 10 minutes;

[0049] ③Use 1C current to discharge to 2.0V, and the discharge ends;

[0050] ④ Sleep for 10 minutes.

[0051] Repeat steps 1-4 for multiple cycles.

[0052] 2. In the middle of the cycle test process of the battery, measure and record the AC internal resistance IR of the battery at room temperature after the 0th cycle (that is, before the cycle), 500 times, 1000 times, 1500 times, and 2000 times. 0 and DC internal resistance DCIR 0 . Take the X-axis as the number of cycles, and the Y-axis as the internal r...

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Abstract

The invention discloses a method for inferring the internal DC resistance of a lithium ion battery. The method comprises the steps of performing cyclic tests on a sampled battery in the environment of a certain temperature and certain humidity, and testing the internal AC resistance IR0 and the internal DC resistance DCIR0 in a certain SOC state every certain cycles, establishing an IR-DCIR linear relation according to the internal AC resistance IR0 and the internal DC resistance DCIR0, when inferring the internal DC resistance of a battery in same model with the sampled battery, measuring the internal AC resistance IR of the battery to be tested at the same frequency according to the SOC state and the temperature and humidity conditions when the internal AC resistance of the sampled batter is measured, comparing the measured internal AC resistance IR with the established IR-DCIR linear relation, and performing ratiometric conversion on the internal AC resistance to obtain the internal DC resistance of the battery. The method for inferring the internal DC resistance of the lithium ion battery is capable of inferring the internal DC resistance according to the linear relation of the internal AC resistance and the internal DC resistance and avoiding the harm of multiple internal DC resistance tests by use of large current discharge to the battery, and also capable of obtaining higher detection speed and accuracy.

Description

technical field [0001] The invention belongs to the technical field of direct current internal resistance detection of lithium ion batteries, and in particular relates to a method for estimating direct current internal resistance of lithium ion batteries. Background technique [0002] The internal resistance of the battery has a great influence on the discharge performance of the battery, especially when the discharge current increases. Generally, what is measured is the AC internal resistance of the battery, that is, it is measured with an AC tester at a certain frequency. The test of the AC internal resistance will not cause too much damage to the battery. Some regular and professional customers often require the DC internal resistance of the battery, and the AC internal resistance of the battery is often called ohmic internal resistance. Compared with AC internal resistance, DC internal resistance includes ohmic internal resistance and activation impedance. Therefore, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R27/02
Inventor 秦红莲刁志中高飞张娜
Owner TIANJIN LISHEN BATTERY
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