In December 2012, the International Electrotechnical Commission (IEC) officially released the second version of IEC 62133 for battery products, IEC 62133:2012 (ed2.0). This standard mainly targets the safety requirements of single-unit batteries and battery packs containing alkaline or non-acid electrolytes, portable sealed single-unit batteries and battery packs (including lithium batteries, nickel-hydrogen batteries, nickel-cadmium batteries, etc.). The test clauses of the new version of IEC 62133 are divided into two major sectors: nickel battery system and lithium battery system. This article uses the lithium battery system as an example to introduce the main changes. New test items such as forced internal short circuit, overcharging (pack), transportation tests, and design suggestions for lithium batteries have been added to the test projects. At the same time, the charging steps and continuous low-voltage charging test items have been updated.
Updated charging steps
According to the requirements of the new version of IEC 62133, when the battery cell tests the following three external short circuits, thermal shock, extrusion, and battery tests the external short circuit, the battery cell or battery charging needs to be carried out at the peak of the charging temperature.
Newly enhanced internal short circuit test
The purpose of this test is to simulate the potential danger of piercing the diaphragm between the positive and negative electrodes and causing internal short circuits. The test targets are cylindrical or prismatic cells. Currently, this test is only applicable to South Korea, Japan, Switzerland and France.
Added transportation test
According to the requirements of the new version of IEC 62133, lithium batteries must pass relevant tests in accordance with the requirements of IEC 62281, and their test items are the same as UN38.3 test items. Therefore, if the manufacturer can provide documents that prove that it meets UN transportation requirements, the transportation test may be directly determined to pass the transportation test without testing.
The IEC 62133 standard mainly includes testing of the following items:
Cell: continuous low-rate charging, vibration, temperature cycle, external short circuit, internal short circuit, free fall, impact (collision), thermal misuse (thermal shock), extrusion, low air pressure, overcharging, forced discharge, high-rate charging protection function (lithium system), labeling and packaging, transportation test, incorrect installation (nickel system). Battery: vibration, housing stress at high temperature, temperature cycle, external short circuit, internal short circuit, free fall, impact (collision), marking and packaging, transportation test, overcharging (nickel system). Among these test and verification projects, most of them are common routine test projects, but some projects are still worth noting and paying attention to: 1.13KN extrusion. The test target of this project is a battery cell. Although it is a common and conventional project, it clearly requires that square battery cells be squeezed with long and short axial directions, that is, the length and width of the battery cell. According to testing experience, when the polymer flexible packaging battery cell is extruded (side), there are sometimes unqualified phenomena such as combustion or explosion. Therefore, for polymer flexible packaging batteries, it is recommended to pay attention to this project. 2. Continuously low-speed charging. The test target for this project is a battery cell. The standard stipulates that the fully charged battery cells will be charged for 28 days in accordance with the charging method specified by the manufacturer. This project is not common in other safety standards. Given that the charging methods specified by battery manufacturers are basically constant current and constant voltage charging, this requires manufacturers to fully consider the cut-off voltage when regulating and limiting the charging current and even the cut-off voltage when fully charged, and if necessary, consider the battery cell resistance when designing it.
Huake Testing Battery Laboratory has carried out a number of battery standard testing services, such as UN38.3, Wercs registration, EN/IEC 62133 testing, etc. Given the complexity of battery cells and batteries and the inspection of finished products, it is recommended that battery manufacturers understand the details of this standard before inspection and verification and control them in production, so as not to delay the final time of battery products during inspection because they do not comply with the requirements of EN/IEC 62133.
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