In December 2012, the International Electrotechnical Commission(IEC) officially released the international safety standard IEC 62133 second version IEC 62133:2012(ed2 .0) for battery products. This standard is mainly for the safety requirements of monomer batteries and batteries containing alkaline or non-acidic electrolytes and portable sealed monomer batteries and batteries(including lithium cells, nickel-metal hydride cells, nickel-cadmium cells, etc.).
The new IEC 62133 test terms are divided into two parts: the nickel battery system and the lithium battery system. This article introduces the main changes in the lithium battery system.
In the test project, mandatory internal short circuit, overcharge(pack), transport test and other test items have been added, as well as design recommendations for lithium batteries. At the same time, the charging steps and continuous low voltage charging test items were updated.
Updated charging steps
According to the requirements of the new IEC 62133, when the core tests the following three external short circuits, heat shocks, extrusion, and the battery tests the external short circuit, the core or battery charging needs to be performed at the peak of the charging temperature.
Additional mandatory internal short circuit testing
The purpose of the test is to simulate the potential danger of impurities such as metal dust and shredded particles that may enter the core during the manufacturing process and puncture the diaphragm between positive and negative poles to cause an internal short circuit. Its test object is cylindrical or Prismatic core. At present, the test is only applicable to South Korea, Japan, Switzerland and France.
Add Transport Test
According to the new IEC 62133 requirements, lithium batteries must pass relevant tests in accordance with IEC 62281 requirements. Its test items are the same as UN 38.3 test items. Therefore, if the manufacturer can provide documents attesting to the UN transport requirements, the transport test will not be required to test and will directly determine the transport test.
The IEC 62133 standard mainly includes tests for the following items:
Cell: Continuous low rate charging, vibration, temperature cycle, external short circuit, internal short circuit, free fall, impact(collision), thermal misuse(thermal impact), extrusion, low pressure, overcharge, forced discharge, high rate charging protection Function(lithium system), marking and packaging, transport testing, incorrect installation(nickel system).
Battery: vibration, shell stress at high temperatures, temperature cycle, external short circuit, internal short circuit, free fall, impact(collision), marking and packaging, transportation test, overcharge(nickel system).
Most of these testing and verification projects are common routine testing projects, but there are still some projects that deserve attention and attention:
1.13 KN extrusion. The test object of this project is the core. Although it is a common conventional item, because it clearly requires that the square core needs to squeeze long and short axial directions, that is, the length and width of the core. According to the test experience, when the polymer soft packaging core is squeezed on the width axis(side), there is an unqualified phenomenon such as combustion or explosion. Therefore, for the polymer soft packaging core, it is suggested that this project should be focused on.
2. Continue low rate charging. The test object for this project is the core. The standard requires that the core that has been fully charged be continuously charged for 28 days according to the charging method specified by the manufacturer. This project is not common in other safety standards. Since the charging method specified by the battery manufacturer is basically constant current constant voltage charging, this requires the manufacturer to fully consider the cut-off voltage at the time of setting and limiting the charging current or even full charging. If necessary, continuous charging capacity should be considered in the design of the core.
A number of battery standard test services such as UN 38.3, Wercs registration, EN/IEC 62133 testing are carried out by the Kew Test Battery Laboratory. In view of the complexity of the manufacturing and testing of electric cores and batteries, it is recommended that battery manufacturers should understand the details of the standard and control it in production before testing and verification. In order not to delay the final listing of battery products in the test because it does not meet the EN/IEC 62133 standard requirements.