Lithium-ion Battery Environmental Safety Test
Lithium-ion batteries, and a whole sample consisting of non-user replaceable batteries/lithium-ion batteries and their electronics. For non-user-replaced batteries, they should be installed in electronic products as a whole sample for standard lithium-ion battery environmental safety tests; For non-user replacement lithium-ion batteries, they can be placed in electronic products as an overall sample, or the lithium-ion batteries can be removed separately for standard lithium-ion battery environmental safety tests, and it is recommended to give priority to testing as an overall sample. Since degassing, smoke, fire and even explosion may occur during the test, it is necessary to take the necessary protective measures, such as the sample is placed in a ventilation device with explosion-proof function.
1.Low Air Pressure
Test purpose: Low pressure test is used to simulate the impact of low air pressure conditions on the safety of lithium-ion batteries during airlift, and the sample should not catch fire, not explode, and not leak after the test. Instruments and equipment: such as vacuum chamber (or low pressure test chamber) charge and discharge tester.
Test purpose: Lithium-ion battery temperature cycle test is used to simulate lithium-ion battery in the process of transportation or storage, repeated exposure to low temperature and high temperature environment, test lithium-ion battery safety test is the use of rapid and extreme temperature changes. After the test, the sample should not catch fire, not explode, and not leak. Instruments and equipment: such as temperature test chambers, charge and discharge testers, etc.
Test purpose: This test simulates the safety problems such as leakage, fire and explosion of lithium-ion batteries during transportation and carrying. Instruments and equipment: such as vibration test machine, charge and discharge tester, etc.
Note: Lithium-ion battery vibration test needs to pay attention to the following points:
1) The fixed way of the sample must ensure that the vibration signal is accurately transmitted to the sample, and the sample cannot be deformed:
2) Each sample needs to withstand the vibration test in different directions several times in a row;
3) Regarding the direction of the test, since the shape of the lithium-ion battery may be irregular in shape, it is necessary to test each other vertically. In addition, it should be noted that a discharge charge cycle is also required after the lithium-ion battery vibration test (it is recommended that a special fixture should be used to ensure that the vibration process does not cause the sample to shift and change the G value).
Test purpose: Lithium-ion battery acceleration impact test is to simulate lithium-ion battery carrying or transportation process after encountering acceleration impact should not cause fire, explosion or leakage and other safety issues. Instruments and equipment: such as acceleration impact test bench, charge and discharge tester, etc.
Note: Lithium-ion battery acceleration shock test needs to pay attention to the following points:
1) Lithium-ion battery acceleration shock test is similar to lithium-ion battery vibration test, and it is necessary to pay attention to the fixing method of the sample, the multiple tests of each sample, and the direction of the test.
2) The precautions for the peak acceleration of the lithium-ion battery acceleration impact test are the same as the acceleration impact test of the battery.
3) In addition, it should be noted that a discharge charge cycle is also required after the acceleration test of the lithium-ion battery.
The two end faces of cylindrical and button-type lithium-ion batteries are dropped once, and the cylindrical surface is dropped twice for a total of four drop tests: the opposing lithium-ion batteries fall once on each side, and a total of six tests are carried out; Drop test equipment with equipment for non-user-replaceable batteries/lithium-ion batteries is dropped once on each side. The batteries should not fire, explode, or leak.
Purpose of the test: This test simulates accidental drops during transportation, carrying, and use (such as falling from benches, table, and hands) that should not cause safety issues such as leaky caught fire and explosion of lithium-ion batteries. This test simulates reasonably foreseeable accidental falls without regard to safety issues caused by deliberate, unreasonable and unforeseen falls. Instruments and equipment: such as multi-degree of freedom test bench, charge and discharge tester, etc.
Note: Lithium-ion battery drop test needs to pay attention to the following points:
1) Each sample needs to withstand the drop test in different directions for many consecutive times;
2) Necessary measures need to be taken to ensure the accuracy of the test direction and to ensure that the measure should not affect the free fall movement;
3) Lithium-ion battery drop test conditions also consider the accidental drop during actual use, so for some lithium-ion batteries need to carry out a 1.5 m drop test: In addition, it should be noted that the lithium-ion battery drop also needs to be discharged and charged.
6.Use at high temperature
Samples should be used with sufficient safety at high temperatures. The following high-temperature use test is used to verify whether it is qualified: the fully charged sample is placed in a high-temperature test chamber, and the temperature in the test chamber is set to the maximum charge temperature and discharge upper limit temperature of the lithium-ion battery specified by the manufacturer, the maximum charge limit temperature and discharge upper limit temperature of the battery, and the maximum value of 80 °C. After the surface temperature of the sample is stable, it is maintained for 7 h.
The sample should meet one of the following requirements:
1) cut off the circuit, and do not fire, explosion, and leakage;
2) The circuit is not cut off, and the charge and discharge method in the process of high temperature test continues to carry out a discharge charging cycle, and the sample should not catch fire, not explode, and not leak.
Purpose of the test: This test simulates the safety of lithium-ion batteries when used in high-temperature environments. For example, a mobile phone that is in standby or on-board charging is forgotten in a car that has been exposed to sunlight for a long time. Instruments and equipment: such as high temperature test chambers, charge and discharge testers, etc.
Note: Lithium-ion battery high temperature test needs to pay attention to the following points:
1)high temperature holding time 7 h to start the timekeeping after the sample surface temperature equilibrium, if the time of a discharge charging cycle is greater than 7 h, the high temperature test time can be extended to the end of the charge and discharge cycle.
2) The choice of test temperature is to select the upper charging limit temperature of the lithium-ion battery (such as 40 ° C) and the upper discharge limit temperature (such as 55 ° C) The battery’s upper charging limit temperature (such as 45 ° C) and the discharge upper limit temperature (such as 60 ° C and 80 ° C). In general, the upper charging limit temperature of the lithium-ion battery The upper charging temperature of the battery <80 °C The discharge limit temperature of the lithium-ion battery The discharge upper limit temperature of the battery <80 °C So the test temperature is generally selected as 80 °C.
3) Because the air flow in the test chamber will accelerate heat transfer, resulting in heat loss on the surface of the battery during charging and discharging, it may be necessary to reduce the wind speed and other methods to minimize the impact on the sample.