The accuracy of the aging cabinet is a key indicator in the production process of battery PACK, which directly affects the accuracy and reliability of battery performance testing. The following provides a detailed explanation of common precision requirements and industry standards for aging cabinets from different parameter dimensions:
1、 Accuracy requirements for core parameters of aging cabinets
1. Voltage accuracy
Measurement accuracy: It is usually required to achieve ± (0.1%~0.5%) FS (full range), and high-precision equipment can reach ± 0.1% FS.
For example, when the full range is 100V, the error range is between ± 0.1V and ± 0.5V.
Control accuracy: ± (0.1%~0.5%) FS, ensuring voltage stability during charging/discharging process.
Application scenario: When used for charging and discharging tests of lithium battery packs, insufficient voltage accuracy can lead to overcharging or overdischarging of the battery, affecting its lifespan assessment.
2. Current accuracy
Measurement accuracy: ± (0.1%~1%) FS, high-end equipment can reach ± 0.1% FS.
For example, when the full scale is 100A, the error range is between ± 0.1A and ± 1A.
Control accuracy: ± (0.1%~1%) FS, ensuring stability of constant current charging and discharging.
Key role: Current accuracy affects the calculation accuracy of battery capacity (Ah), which in turn affects the energy density evaluation of PACK.
3. Temperature control accuracy
Temperature uniformity inside the box: ± (1-3) ℃, high-precision equipment can reach within ± 1 ℃.
Temperature control accuracy: ± (0.5~2) ℃, ensuring consistent performance testing of the battery at different environmental temperatures.
Example: During high-temperature aging (such as 55 ℃) or low-temperature testing (such as -20 ℃), excessive temperature fluctuations can lead to deviations in battery performance data.
4. Time accuracy
Timing error: ± (1-5) seconds/hour, meeting the timing requirements for long-term aging testing (such as 72 hours of continuous operation).
Importance: When used to calculate battery cycle life, time errors can affect the statistical accuracy of the number of cycles.
2、 Accuracy differences in different application scenarios
Application scenarios Voltage accuracy Current accuracy Temperature control accuracy
Consumer electronics battery PACK ± 0.5% FS ± 1% FS ± 2 ℃
Power lithium battery PACK ± 0.2% FS ± 0.5% FS ± 1 ℃
Energy storage battery PACK ± 0.3% FS ± 0.5% FS ± 1.5 ℃
Research grade battery testing ± 0.1% FS ± 0.1% FS ± 0.5 ℃
3、 Industry reference for precision standards
National and industry standards
GB/T 31486-2015 "Requirements and Test Methods for Electrical Performance of Power Batteries for Electric Vehicles" requires:
The accuracy of voltage/current measuring equipment shall not be less than ± 0.5% FS, and the temperature control accuracy shall be ± 2 ℃.
According to JB/T 7069-2015 "Battery Formation and Charging/Discharging Equipment":
The current/voltage control accuracy of high-precision equipment is ≤± 0.2% FS, and the temperature uniformity is ≤± 1 ℃.
Enterprise standards
Power battery companies (such as CATL and BYD) usually require aging cabinet accuracy:
Voltage ± 0.2% FS, current ± 0.3% FS, temperature ± 1 ℃, to meet the reliability testing of automotive grade batteries.
The consumer electronics field (such as mobile phone battery PACK) generally adopts a voltage/current accuracy of ± 0.5% FS, balancing cost and performance.
4、 Key factors affecting accuracy
hardware configuration
High precision sampling resistor (error ≤ 0.1%), linear power module, PID temperature control algorithm.
calibration frequency
It is recommended to use a high-precision standard source (such as a Fluke multimeter) for calibration every 3-6 months to ensure long-term accuracy.
Environmental interference
The aging cabinet should be kept away from electromagnetic interference sources, well grounded, and avoid voltage/current fluctuations.
