Metal Information Center

Batteries – Operation, Classifications and Materials That Make up a Battery – Supplier Data by Sigma Aldrich

March 21, 2007 – 7:29 am

atteries and fuel cells are electrochemical cells used to generate an external electrical current. They consist of an anode, where oxidation occurs, a cathode, where reduction occurs, and an electrolyte through which ions can travel between electrodes (see Figure 1 for a schematic of a common battery cell). In fuel cells (discussed below), one or both of the reactants are supplied from an external source to the cell. Though technically fuel cells, if the only reactant supplied to the cell is atmospheric oxygen, the cells are then considered batteries.

Batteries can be divided into two types: primary or disposable batteries and secondary or rechargeable batteries. The main advantages of batteries over fuel cells are their availability, portability, low cost, and wide range of operating conditions. Batteries, however, have much shorter life spans and lack the power output of fuel cells. Power outputs of batteries are typically on the order of 100’s of watts, whereas fuel cells can provide kilowatt to megawatt outputs, power enough to light a building or fuel a vehicle for hours. Under heavy energy demands, batteries can build up dangerous levels of heat and pressure, degrading the battery and possibly causing leaks of toxic compounds or even explosions. In addition, the limited life of primary batteries and the limited cycle life (number of times it can be recharged) of most secondary batteries necessitate the need for disposal of often dangerous and toxic battery materials. Table 1 summarizes some of the common types of primary and secondary batteries.