BS IEC 63057:2020 pdf download – Secondary cells and batteries containing alkaline or other non-acid electrolytes — Safety requirements for secondary lithium batteries for use in road vehicles not for the propulsion
5 General safety considerations
5.1 General The safety of lithium secondary batteries requires the consideration of two sets of applied conditions:
1 ) intended use;
2) reasonably foreseeable misuse. Batteries shall be so designed and constructed that they are safe under conditions of both intended use and reasonably foreseeable misuse. It is expected that batteries subjected to misuse can fail to function. However, even if such a situation occurs, they shall not present any significant hazards. Potential hazards which are the subject of this document are: a) fire, b) explosion. Conformity with 5.1 to 5.7 is checked by the tests of Clauses 6 and 7, and in accordance with the appropriate standard.
5.2 Insulation and wiring Wiring and its insulation shall be sufficient to withstand the maximum anticipated voltage, current, and temperature requirements. The design of wiring shall be such that adequate clearances and creepage distances are maintained between conductors. The mechanical integrity of the battery and its connections shall be sufficient to accommodate conditions of reasonably foreseeable misuse.
5.3 Venting The casing of the battery shall incorporate a pressure relief function that will preclude rupture or explosion. If encapsulation is used to support cells within an outer case, the type of encapsulant and the method of encapsulation shall neither cause the battery to overheat during normal operation nor inhibit pressure relief.
The design of batteries shall be such that abnormal temperature-rise conditions are prevented. The battery shall be designed within voltage, current, and temperature limitations specified by the cell manufacturer. The battery shall be provided with specifications and charge instructions for vehicle manufacturer or battery-charger manufacturer so that associated chargers are designed to maintain charging within the voltage, current and temperature limits specified.
NOTE Where necessary, means can be provided to limit current or voltage to safe levels during charging and discharging.
5.5 Terminal contacts of the battery
Terminals shall have clear polarity marking(s) on the external surface of the battery, and the polarity marking(s) should be located near the terminal in order to be understood easily. 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 (caused by metal tools, for example).
5.6 Assembly of battery
• The battery should have an independent control and protection method.
• The cell manufacturer shall provide recommendations about current, voltage and temperature limits so that the battery manufacturer or designer can ensure proper design and assembly.
• Protective circuit components should be added as appropriate, and consideration given to the vehicle.
5.6.2 Battery design The voltage control function of the battery design shall ensure that the voltage of each cell or cell block shall not exceed the upper limit of the charging voltage specified by the cell manufacturer, except in the case where the vehicle system provides an equivalent voltage control function.
The following should be considered at battery level and by the battery manufacturer: For a battery that has several series-connected cells or modules, it is recommended that the voltages of any one of the single cells or cell blocks do not exceed the upper limit of the charging voltage, specified by the cell manufacturer, by monitoring the voltage of every single cell or cell block.
5.7 Requirements for the BMS The BMS evaluates the condition of cells and batteries, and it maintains cells and batteries within the specified cell operating region. Key factors of the cell operating region are voltage, temperature and current for charging and discharging. The functions of the BMS can be incorporated into the battery or into the vehicle that uses the battery. The BMS can also be divided so that it can be found partially in the battery and partially in the vehicle that uses the battery (see Figure 1 ).