Gassing
A gassing (also outgassing) means at a lead-acid battery , the on voltage of 2.4 volts , (charge voltage) is loaded that instead of a disproportionation of lead sulfate to lead and lead dioxide an electrolysis of water to hydrogen (H 2 ) and oxygen (O 2 ) takes place. The lead accumulator then acts unintentionally as a Hofmann water decomposition apparatus . Gassing can also occur with other types of accumulators with aqueous electrolytes . They are always dangerous because the mixture of the outgassing substances and the mixture of the outgassing H 2 with the O 2 of the ambient air can be flammable or even explosive, depending on the mixing ratio. Gas mixtures with a mixture ratio capable of detonation are therefore also called oxyhydrogen .