In December 2012, the International Electrotechnical Commission (IEC) officially released the second edition of the International Safety Standard IEC 62133:2012 (ed2.0) for battery products. This standard is mainly for the safety requirements of single battery and battery pack containing alkaline or non acid electrolyte and portable sealed single battery and battery pack (including lithium battery, nickel hydrogen battery, nickel cadmium battery, etc.).
The new IEC 62133 test clause is divided into two parts: nickel battery system and lithium battery system. This paper introduces the main changes with the lithium battery system as an example.
Test items such as forced internal short circuit, overcharge, transportation test and design suggestions for lithium battery are added to the test items. At the same time, the charging steps and continuous low-voltage charging test items are updated.
Updated charging procedure
According to the requirements of the new IEC 62133, when the cell tests the following three external short circuits, thermal shock, extrusion, and the battery tests the external short circuit, the cell or battery charging needs to be carried out under the peak value of charging temperature.
New forced internal short circuit test
The purpose of this test is to simulate the potential danger of metal dust, crushed material particles and other impurities that may enter during the manufacturing process of the electric core, when the internal short circuit is caused by piercing the diaphragm between the positive and negative poles. The test object is cylindrical or prismatic core. At present, the test is only applicable to South Korea, Japan, Switzerland and France.
New transport test
According to the requirements of the new IEC 62133, the lithium battery must pass relevant tests in accordance with the requirements of IEC 62281, and the test items are the same as those of UN38.3. Therefore, if the manufacturer can provide documents to prove the conformity with UN transportation requirements, transportation test can be directly judged as qualified without testing.
IEC 62133 mainly includes the following tests:
Cell: continuous low rate charging, vibration, temperature cycle, external short circuit, internal short circuit, free drop, impact (collision), thermal misuse (thermal shock), extrusion, low pressure, overcharge, forced discharge, high rate charging protection function (lithium system), marking and packaging, transportation test, incorrect installation (nickel system).
Battery: vibration, shell stress at high temperature, temperature cycle, external short circuit, internal short circuit, free fall, impact (collision), marking and packaging, transportation test, overcharge (nickel system).
Most of these test and verification items are common routine test items, but there are still some items worthy of attention and attention:
1.13kn extrusion. The test object of this project is the electric core, although it is a common routine project, but because of its clear requirements for the square electric core, it needs to extrude the long and short axis, that is, the length and width of the electric core are two planes. According to the test experience, when the polymer flexible packaging electric core extrudes the width axis (side), there are combustion or explosion and other unqualified phenomena. Therefore, it is suggested to pay more attention to this project.
2. Continuous low-speed charging. The test object of this project is the electric core. The standard stipulates that the fully charged cell shall 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 methods specified by battery manufacturers are basically constant current and voltage charging, it requires manufacturers to fully consider the cut-off voltage when specifying and limiting the charging current and even full charging, and consider the ability to withstand continuous charging when necessary in the design of battery cells.
Hua Ming testing battery laboratory has carried out a number of battery standard testing services, such as UN38.3, wercs registration, en / IEC 62133 testing, etc. In view of the complexity of cell and battery manufacturing and finished product testing, it is suggested that battery manufacturers should understand the details of the standard before testing and verification and control it in production, so as to avoid the delay of the final market time of battery products due to non-compliance with the requirements of en / IEC 62133 standard in testing.