Energizer Design Considerations - Hydrogen Generation

Hydrogen Generation
(alkaline batteries)

• Hydrogen gas is a byproduct of the chemical reaction in all alkaline batteries. Under normal usage, this gas production is very low. However, in abusive conditions, (i.e. charging or shorting) high levels of hydrogen can be produced.

• In devices that use a tightly sealed battery case (i.e. diving lights), the hydrogen gas can mix with air to create an explosive atmosphere.

• The amount of hydrogen generated is dependent on several factors including the number of batteries and their size.

Hydrogen Production per Battery

Size	Normal Usage	Typical Deep Discharge	Abusive Charge
AAAA	0.2 cc	5 cc	645 cc
AAA	0.3 cc	10 cc	1,400 cc
AA	0.5 cc	20 cc	2,300 cc
C	1.4 cc	60 cc	10,300 cc
D	4.2 cc	130 cc	21,800 cc

• Hydrogen gas generation in water proof battery compartments needs to be addressed as a potential safety issue to prevent the accumulation of dangerous levels of hydrogen gas within the device.

1. Hydrogen catalyst pellets (commonly referred to as “getters”) can be used to react the excess hydrogen with oxygen to form water vapor.

Hydrogen Catalyst Pellet

2. Gas permeable venting membranes can be used to allow the escape of hydrogen gas while still keeping the battery case watertight.