What situation is most likely to cause thermal runaway in a nickel-cadmium battery?

Thermal runaway in a nickel-cadmium battery occurs when there is an increase in temperature that accelerates a chemical reaction within the battery, leading to further increases in temperature. A critical factor in this scenario is excessive current draw from the battery.

When a nickel-cadmium battery is subjected to excessive current demand, it can experience increased internal resistance as the battery heats up. This heat generation can lead to further increase in internal resistance and cause the battery to heat up to unsafe temperatures. In extreme cases, this may result in the breakdown of the electrolyte and release of gases, potentially leading to battery failure or even explosion. Therefore, a situation where the battery is drawn excessively beyond its rated output can create the conditions necessary for thermal runaway to occur.

While charging below room temperature and high internal resistance may contribute to battery performance issues, they do not directly lead to the rapid thermal escalation characteristic of thermal runaway. Constant current charging to more than 100 percent of capacity may cause overcharging, but excessive current draw is the primary trigger for thermal runaway due to its immediate impact on the battery’s thermal management system.