Tadiran SL-type Lithium Batteries are recognized by UL under file MH 12827. The following text or a modified version thereof appears on each battery:
Fire, explosion, and severe burn hazard. Do not recharge, disassemble, heat above 100 °C, incinerate, or expose contents to water.
Protection against charging
Whenever lithium batteries are not the single power source in a circuit the following measures are recommended by the Underwriters Laboratories. The battery should not be connected in series with an electrical power source that would increase the forward current through the battery.
The circuit for these cells shall include one of the following:
- Two suitable diodes in series with the battery to prevent any reverse (charging) current. The second diode provides protection if the other one fails.
A blocking diode or the equivalent to prevent any reverse (charging) current and a resistor to limit current in case of a diode failure.
The resistor should be sized to limit the maximum reverse (charging) current IR, max to the values shown in this table.
In addition to this UL requirement which gives the safety limits, Tadiran recommends to limit the reverse (charging) current to values below 10 µA. This will ensure that service life is not affected.
Protection against forced discharge
Forced discharge of a cell can occur when it is connected in series with other cells. A by-pass diode should be provided in parallel with each cell in a series connection. The effect of a by-pass diode is that current passes through the diode if a cell has been discharged, preventing forced discharge.
For further information on UL visit UL at www.ul.com.
For further information regarding the IEC standarts visit the website of the IEC (International Electrotechnical Commission) at www.iec.ch.