Lithium battery performance test method introduction

Lithium battery is a product that requires high quality and high safety. Consumers often don't know the performance of the battery when using it. As a result, the battery's working efficiency often fails to meet the ideal target. Sometimes even blindly use will cause battery explosion, life safety can also be compromised, so understanding the performance of batteries is crucial.

Lithium battery performance test mainly includes voltage, internal resistance, capacity, internal pressure, self-discharge rate, cycle life, sealing performance, safety performance, storage performance, appearance, etc., and other overcharge, over discharge, weldability, corrosion resistance and so on.

Tools/raw material

Tester, rigid rod, nails.

Methods/procedures

Method one, self-discharge test

Nickel cadmium and nickel metal hydride battery self-discharge test is: due to the standard charged keep testing time is too long, generally USES 24 hours self-discharge keep ability to quickly test the charged, at 0.2 to 1.0 C discharge the battery to v. 1 C charge 80 minutes, put on hold for 15 minutes, 1 C discharge to 10 V, measuring the discharge capacity C1, then the battery charge at 1 C 80 minutes, and let sit 24 hours after the testing capacity of 1 C C2, C2 / C1 x 100% should be less than 15%

Lithium battery self-discharge test as follows: generally USES 24 hours self-discharge keep ability to quickly test the charged, at 0.2 to 3.0 V, C discharge battery to charge 1 C constant current constant voltage to 4.2 V, the cut-off current: 10 ma, shelved after 15 minutes, 1 C discharge to 3.0 V test its discharge capacity C1, then the battery charging 1 C constant current constant voltage to 4.2 V, cut-off current 100 ma, 1 C and let sit 24 hours after the test capacity of C2, C2 / C1 x 100% should be greater than 99%.

Method two, internal resistance measurement

Battery internal resistance is refers to the battery at work, current flows through the battery internal resistance, generally divided into ac resistance and dc resistance, because the rechargeable battery internal resistance is very small, when measuring the dc resistance due to the electrode polarization, polarization resistance, the real reason cannot be measured values. And the ac impedance measurement can be exempted from the influence of polarization resistance, it is concluded that the real value.

Ac internal resistance test method is: using the characteristics of the battery is equivalent to an active resistance, battery on a 1000hz, 50 ma, constant current, the voltage sampling rectifier filter and a series of processing so as to accurately measure.

Method three, IEC standard cycle life test

IEC standards prescribed nickel cadmium and nickel metal hydride batteries cycle life test as follows:

Battery to 0.2 C to 1.0 V/after

1. Charge at 0.1 C 16 hours, 2 hours and 30 minutes to 0.2 C discharge (a loop).

2.0.25 C charge 3 hours, 10 minutes to 2 hours and 20 minutes 0.25 C discharge (2-48 cycles).

Charging 3.0.25 C 3 hours, 10 minutes to 0.25 C to 1.0 V (49 cycle)

4.0.1C charging for 16 hours, leaving for 1 hour, 0.2C discharge to 1.0V (50th cycle), after repeating 1-4 for 400 cycles of nickel-hydrogen battery, the 0.2C discharge time should be greater than 3 hours; The battery is repeated 1-4 for a total of 500 cycles, and its 0.2C discharge time should be greater than 3 hours.

IEC standards prescribed lithium battery cycle life test as follows:

Battery to 0.2 C to 3.0 V/branch, 1 C constant current constant voltage charging to 4.2 V, cut-off current 20 ma, put aside an hour later, to 0.2 to 3.0 V C discharge (a loop) recycling capacity after 500 times should be more than 60% of the initial capacity.

Method four, internal pressure test

Nickel cadmium and nickel metal hydride battery internal pressure test as follows:

After the battery was placed at 1.0C to 1.0V, it was charged at 1C for 3 hours. According to the slight deformation of the battery steel shell, the internal pressure of the battery was obtained by conversion. The battery should not be bottomed, leaked or exploded during the test.

Lithium battery internal pressure test: (UL standard)

Simulated battery at an altitude of 15240 m high (11.6KPa pressure), see if battery leakage or drum.

Specific steps: the battery charging constant current constant voltage charging 1 c to 4.2 V, cut-off current of 10 ma, then put it in a pressure of 11.6Kpa, temperature of (20 + / - 3 ℃) in the low pressure store 6 hours, the battery will not explosion, fire, cracks and leakage.

Method five, the drop test

After fully charging the battery pack, it will fall on the hard rubber board from three different directions at a height of 1m, and do it twice in each direction. The battery pack should have normal electrical performance and no damage to the outer packaging.

Method six, vibration test

Nickel cadmium and nickel metal hydride batteries vibration experiment method is:

Battery with 0.2 C after discharge to 1.0 V, 0.1 C 16 hours of charging, and let sit 24 hours after vibration according to the following conditions:

Amplitude: 4 mm

Frequency: 1000 times, the XYZ three directions each vibration for 30 minutes.

Battery voltage change after vibration should be between + / - 0.02 V, resistance changes within + / - 5 m

Lithium battery vibration experiment method is:

Battery 3.0 V to 0.2 C discharge after charging constant current constant voltage charging 1 C to 4.2 V, cut-off current of 10 ma, and let sit 24 hours after vibration according to the following conditions:

The amplitude of 0.8 mm

Make a battery in vibration between 10Hz – 55Hz, per minute to increases or decreases vibration rate of 1Hz.

Battery voltage change after vibration should be between + / - 0.02 V, internal resistance change within 5 m.

Method seven, the impact experiment

After a full charge, will be a 15.8 mm diameter of rigid rods placed horizontally on the battery, use a 20 pounds of weight from the height of 610 mm falls on the rigid rod, battery should not burst into flames or leakage.

Method eight, puncture test

After a full charge, with a diameter of 2.0 mm to 25 mm nails through the center of the battery, and left the nail inside the battery, the battery should not burst into flames.

Method 9, high temperature and high humidity test

Nickel cadmium and nickel metal hydride battery high temperature and high humidity test for:

Battery 1.0 V to 0.2 C discharge after charging 1 C 75 minutes to buy and the temperature of 66 ℃, 85% humidity store 192 hours (8 days), interesting often wet shelved under 2 hours, the battery should not be deformation or fluid leakage, capacity should be more than 80% of the nominal capacity recovery.

High temperature and high humidity test for lithium-ion batteries (national standard)

Constant current constant voltage charging the battery 1C to 4.2V, cut-off current of 10ma, then add (40 plus or minus 2 ℃) and relative humidity is 90% - 95% of the constant temperature and humidity box shelved after 48h, remove the battery under the condition of (20 + / - 5 ℃) on 2h, observed the battery should be no abnormal phenomenon appearance, again with 1 c electric constant exile to 2.75V, and then under the condition of (20 + / - 5 ℃), battery by 1C, 1C discharge cycle until the discharge capacity of not less than 85% of the initial capacity, but not more than three cycles.

Precautions：

Test time set aside for 24 hours

Test security measures need to be done well

Cycle test no more than three times

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