UL 1642:2020 free download

UL 1642:2020 free download Lithium Batteries
12 Forced-Discharge Test
12.1 This test is intended for cells that are to be used in series-connected, multicell applications, such as battery packs.
12.2 A fully discharged cell is to be force-discharged by connecting it in series with fully charged cells of the same kind. The number of fully charged cells to be connected in series with the discharged cell is to equal the maximum number less one of the cells to be covered for series use. Five cells are to be fully discharged, at room temperature.
12.3 Once the fully discharged cell is connected in series with the specified number of fully charged cells the resultant battery pack is to be short circuited.
12.4 The positive and negative terminals of the sample are to be connected with a resistance load of 80 ±20 mΩ. The sample is to discharge until a fire or explosion is obtained, or until it has reached a completely discharged state of less than 0.2 V and the battery case temperature has returned to ±10°C (18°F) of ambient temperature. The voltage at the end of the test may not reach 0.2 V due to operation of protective devices in the circuit. The return to near ambient of the cell casing is an indication of ultimate results.
12.5 When an overcurrent protective device operates during the test, the test shall be repeated with the battery supply connected to the maximum load that does not cause the protective device to open. Protective devices that are relied upon to meet the compliance criteria for the forced discharge test shall comply with 2.3.1.
12.6 The samples shall not explode or catch fire. MECHANICAL TESTS
13 Crush Test
13.1 A battery is to be crushed between two flat surfaces. The force for the crushing is to be applied by a hydraulic ram or similar force mechanism. The flat surfaces are to be brought in contact with the cells and the crushing is to be continued until an applied force of 13 ±1 kN (3000 ±224 lbs) is reached. Once the maximum force has been obtained it is to be released.
13.2 A cylindrical, pouch or prismatic cell is to be crushed with its longitudinal axis parallel to the flat surfaces of the crushing apparatus. A prismatic cell is also to be rotated 90° around its longitudinal axis so that both the wide and narrow sides will be subjected to the crushing force. Each sample is to be subjected to a crushing force in only one direction. Separate samples are to be used for each test. Exception: For lithium ion systems, a cylindrical, pouch or prismatic cell is to be crushed with its longitudinal axis parallel to the flat surfaces ofthe crushing apparatus. Each sample is to be subjected to a crushing force in onlyone direction. Test onlythe wide side ofpouch and prismatic cells.