Rechargeable alkaline battery

A rechargeable alkaline battery (also known as alkaline rechargeable or rechargeable alkaline manganese (RAM)) is a type of alkaline battery that is capable of recharging for repeated use. The first-generation rechargeable alkaline technology was developed by Battery Technologies Inc in Canada and licensed to Pure Energy, EnviroCell, Rayovac, and Grandcell. Subsequent patent and advancements in technology have been introduced. The formats include AAA, AA, C, D, and snap-on 9-volt batteries. Rechargeable alkaline batteries are manufactured fully charged and have the ability to hold their charge for years, longer than NiCd and NiMH batteries, which self-discharge. Rechargeable alkaline batteries can have a high recharging efficiency and have less environmental impact than disposable cells.

Most alkaline batteries available are disposable, designed to be used until exhausted, then discarded. There are also rechargeable alkaline batteries, designed to be recharged.

Disposable alkaline batteries are classed as primary batteries; manufacturers do not support recharging, and warn that it may be dangerous. Despite this advice, alkaline batteries have successfully been recharged, and suitable chargers have been available. The capacity of a recharged alkaline battery declines with number of recharges, until it becomes unusable after typically about ten cycles.

Low-ripple direct current is not suitable for charging disposable alkaline batteries; more suitable is a current pulsed at a rate of 40 to 200 pulses per second, with an 80% duty cycle. Pulsed charging appears to reduce the risk of electrolyte—usually potassium hydroxide (KOH)—leakage. The charging current is low to prevent rapid production of gases that can rupture the cell. Cells that have leaked electrolyte are a safety hazard and unsuitable for reuse. Fully discharged cells recharge less successfully than only partly depleted cells, particularly if they have been stored in a discharged state —battery charger manufacturers do not claim to recharge dead cells.

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Wikipedia