Battery Testing

1Battery TestingThe 'Four Core Physical Examination Items'

1. Basic item: Voltage/Capacity Test

• Professional Key Points：

• Laboratory level testing needs to be conducted in a constant temperature chamber of 20 ± 2 ℃ (temperature drift error is usually ignored for civilian equipment)

• The true capacity needs to be measured through a constant current discharge of 0.2C (with an error rate of up to 15% for market measuring instruments)

2. Key item: DC internal resistance (DCR) detection

• Testing institution methods：

• Adopting 1000Hz AC injection method+four wire measurement (comparison chart: data difference between professional equipment and ordinary multimeter)

• Exceeding the standard case: If the internal resistance of a certain brand's power battery is greater than 2m Ω, it is judged as the retirement critical value (attached is an excerpt from our testing report)

3. Hidden item: Self discharge rate test

• industry standard：

• Lithium ion batteries with a voltage drop of ≤ 10mV within 72 hours are considered qualified (as shown in the actual photo taken by the testing institution's dedicated static stand)

• The abnormal case we found: a batch of batteries had a daily self discharge rate of 3% (normal value<0.5%) due to membrane defects

4. Safety item: Thermal runaway test

• laboratory live scene：

• Overcharge to 150% SOC and observe the thermal spread speed (video screenshot: infrared thermal imager monitoring screen)

• detectionData: Thermal runaway triggering temperature ≥ 130 ℃ is qualified (GB 38031-2020 standard)

2、 Unveiling the workflow of testing institutions

Step 1 Sample pre-processing

• Disassembly of ultra clean room (actual photo of anti short circuit operation platform)

• Analysis of electrode powder detachment using laser particle size analyzer

Step 2 Accelerated Aging Test

• 85 ℃ high-temperature storage+charge discharge cycle simulation for 5-year decay (illustrated by our aging testing equipment)

Step 3 Data Modeling

• Predicting battery life curve using Weibull distribution (with a failure analysis model we developed for a certain automotive company)

3、 How do consumers make initial judgments about battery health?

Although professional testing requires precision equipment, daily warnings can be issued through the following methods:

• Simple detection method：

• After being fully charged and left idle for 24 hours, the voltage drops by more than 5%, indicating the possibility of a micro short circuit

• Temperature difference on battery surface during charging>8 ℃ → Abnormal heat dissipation (requires assistance from FLIR thermal imager)

• Suggestions for inspection：
  When the following situations occur, it is recommended to contact a professional organization for testing:
  ✅ Electric vehicle range suddenly drops by more than 20%
  ✅ Battery swelling/leakage
  ✅ Abnormal heating during fast charging

4、 What can testing agencies do for you?

1. detectionreport：

• Testing reports that comply with international standards such as UN38.3 and IEC 62660

2. Failure Analysis：

• Localization of micro defects such as membrane perforation through SEM electron microscopy

3. customized solution：

• Provide a battery cluster health assessment system for energy storage power plants