UL 62133-2017 pdf download – Secondary Cells and Batteries Containing Alkaline or Other Non-Acid Electrolytes – Safety Requirements for Portable Sealed Secondary Cells, and for Batteries Made From Them, for Use in Portable Applications.
5.4 Temperature/voltage/current management The design of batteries shall be such that abnormal temperature-rise conditions are prevented. Batteries shall be designed to be within temperature, voltage and current limits specified by the cell manufacturer. Batteries shall be provided with specifications and charging instructions for equipment manufacturers so that associated chargers are designed to maintain charging within the temperature, voltage and current limits specified. NOTE Where necessary, means can be provided to limit current to safe levels during charge and discharge. 5.5 Terminal contacts Terminals shall have clear polarity marking on the external surface of the battery. The size and shape of the terminal contacts shall ensure that they can carry the maximum anticipated current. External terminal contact surfaces shall be formed from conductive materials with good mechanical strength and corrosion resistance. Terminal contacts shall be arranged so as to minimize the RISK of short circuits. NOTE Exception: Battery packs with keyed external connectors designed for connection to specific end products need not be marked with polarity markings if the design of the external connector prevents reverse polarity connections. 5.6 Assembly of cells into batteries 5.6.1 General If there is more than one battery housed in a single battery case, cells used in the assembly of each battery shall have closely matched capacities, be of the same design, be of the same chemistry and be from the same manufacturer. Each battery shall have an independent control and protection. Manufacturers of cells shall make recommendations about current, voltage and temperature limits so that the battery manufacturer/designer may ensure proper design and assembly. Batteries that are designed for the selective discharge of a portion of their series connected cells shall incorporate separate circuitry to prevent the cell reversal caused by uneven discharges.
5.6.2 Design recommendation for lithium systems only The voltage of each cell, or each cellblock consisting of parallel-connected plural cells, should not exceed the upper limit of the charging voltage specified in Table 4, excepting the case where the portable electronic devices or the likes have the equivalent function. The following should be considered at the battery pack level and by the device designer: • for the battery consisting of a single cell or a single cellblock, it is recommended that the charging voltage of the cell does not exceed the upper limit of the charging voltage specified in Table 4; • for the battery consisting of series-connected plural single cells or series-connected plural cellblocks, it is recommended that the voltages of any one of the single cells or single cellblocks does not exceed the upper limit of the charging voltage, specified in Table 4, by monitoring the voltage of every single cell or the single cellblocks; • for the battery consisting of series-connected plural single cells or series-connected plural cellblocks, it is recommended that charging is stopped when the upper limit of the charging voltage is exceeded for any one of the single cells or single cellblocks by measuring the voltage of every single cell or the single cellblocks.