Recently International Electrotechnical Commission EE has approved, released and canceled several CTL resolutions on batteries, which mainly involves portable battery certification standard IEC 62133-2, energy storage battery certificate standard IEC 62619 and IEC 63056. The following is the specific content of the resolution:

IEC 62133:2017，IEC 62133:2017 +AMD1:2021：cancel the battery 60Vdc limit voltage requirement

In December 2022, CTL issued a resolution that the voltage of the battery pack products cannot exceed 60Vdc. There is no clear statement about voltage limit in IEC 62133-2, but it refers to the IEC 61960-3 standard.

The reason why this resolution was cancelled by CTL is that “the upper voltage limit of 60Vdc will restrict some industry products from undergoing this standard test, such as power tools, etc.”

(PDSH 2211)

IEC 62133:2017，IEC 62133:2017 +AMD1:2021：cancel the charging temperature operating requirement

Similarly, in the interim resolution issued in December last year, it was proposed that when charging at the method of Article 7.1.2 (requiring charging at the upper and lower charging temperature limits), although in Appendix A.4 of the standard it states that when the upper/lower charging temperature is not 10℃/45℃, the expected upper charging temperature needs to be +5℃ and the lower charging temperature needs to -5℃. However, during the actual test, the +/-5°C operation can be omitted and charging can be carried out according to the normal upper/lower limit charging temperature.

This resolution was passed at this year’s CTL plenary meeting.

(DSH 2210)

IEC 62619:2017：utilize third-party developed BMS for safety assessment on battery function

This resolution is about the safety assessment of battery BMS systems function.

Now most battery manufacturers purchase BMS from the third parties, which may result in battery manufacturer not being able to understand the detailed BMS design. When the testing agent conducts functional safety assessment through Annex H of IEC 60730-1, the manufacturer cannot provide the source code of the BMS.

In this case, the testing agent can evaluate the source code independently with the BMS manufacturer to protect its intellectual property rights. The functional safety analysis of battery system is essential, and the assessment cannot be canceled just because the battery manufacturer cannot provide the source code.

At present, the resolution is still a temporary resolution and will be approved at the CTL plenary meeting in 2024. （PDSH 2230）

IEC 63056:2020：insulation resistance test voltage

IEC 63056:2020 Clause 7.4 (Electrical insulation inspection during transportation and installation) refers to IEC 62133:2017 for insulation resistance testing. This is an editing error. The reference should be IEC 62133-2:2017. This error has been notified to IEC TC21A.

IEC 63056 standard can cover products with a maximum voltage of 1500Vdc, but the test voltage of IEC 62133-2:2017 insulation resistance test is 500Vdc. If the maximum voltage of the battery system exceeds 500Vdc, which test voltage should be used?

Insulation resistance testing still uses IEC 62133-2:2017 5.2 for evaluation. The wires and insulation should be sufficient to withstand the maximum expected voltage and evaluated according to the requirements of IEC 60950-1:2005, 3.1 and 3.2 (refer to IEC 63056: 2020 clause 5.2).

Refer to the figure below, when performing insulation resistance testing, there are two ways to connect the insulation resistance tester. When the test device and the test sample are connected in series, their voltages will be superimposed, and some insulation of the battery system may withstand test voltage beyond the range. Should series testing be performed at this time?

Series connections that would cause voltage superposition are not suitable. The reason for this difference is that the purpose of IEC 63056:2020 is to measure the “insulation resistance of DC contacts and system protective conductor potentials”. The purpose of IEC 62133-2:2017 is to measure “the insulation resistance between the positive terminal of the battery and external exposed metal surface (excluding electrical contact surface). At present, this resolution is still a temporary resolution and will be approved at the CTL plenary meeting in 2024. （PDSH 2229）