Overview

UL 1973：2022 was published on 25th February. This version is based on two suggestion draft issued in May and October of 2021. The modified standard expands its range, including vehicle assistant energy system (e.g.  illumination and communication).

Change of emphasis

1.Append 7.7 Transformer: transformer for battery system shall be certificated under UL 1562 and UL 1310 or relevant standards. Low voltage can be certificated under 26.6.

2.Update 7.9: Protective Circuits and Control: battery system shall provide switch or breaker, the minimum of which is required to be 60V instead of 50V. Extra requirement for instruction for overcurrent fuse

3.Update 7.12 Cells (batteries and electrochemical capacitor): For rechargeable Li-ion cells, test under annex E is required, without considering UL 1642. Cells are required also to be analyzed if meet demand of safe design, like material and position of insulator, the coverage of anode and cathode, etc.

4.Append 16 High Rate Charge: Evaluate charging protection of battery system with over maximum charging current. Need to test in 120% of maximum charging rate.

5.Append 17 Short Circuit Test: Conduct short circuit test for battery modules that need filed installation or change.

6.Append 18 Overload Under Discharge: Evaluate battery system ability with overload under discharge. There are two conditions for the test: first is in overload under discharge in which current is higher than rated maximum discharging current but lower than current of BMS overcurrent protection; the second is higher than BMS over current protection but lower than level 1 protection current.

7.Append 27 Electromagnetic Immunity Test: totally 7 tests as follow:

• Electrostatic discharge (reference IEC 61000-4-2)
• Radio-frequency electromagnetic field (reference IEC 61000-4-3)
• Fast transient/burst immunity (reference IEC 61000-4-4)
• Surge immunity (reference IEC 61000-4-5)
• Radio-frequency common mode (reference IEC 61000-4-6)
• Power-frequency magnetic field (reference IEC 61000-4-8)
• Operational verification

8.Append 3 annex: annex G (informative) Safety marking translation; annex H (normative) Alternative approach for evaluating valve regulated or vented lead acid or nickel cadmium batteries; annex I (normative) : test program for mechanically rechargeable metal-air batteries.

Caution

UL 1642 certificate for cells will no longer be recognized for batteries under UL1973 certification.