Page 88 - Solar Power in Building Design The Engineer's Complete Design Resource

58 SOLAR POWER SYSTEM DESIGN CONSIDERATIONS

Figure 3.8 Alessandro
Volta’s pile.

The battery is an electric energy storage device that in physics terminology can be
described as a device or mechanism that can hold kinetic or static energy for future
use. For example, a rotating flywheel can store dynamic rotational energy in its wheel,
which releases the energy when the primary mover such as a motor no longer engages
the connecting rod. Similarly, a weight held at a high elevation stores static energy
embodied in the object mass, which can release its static energy when dropped. Both
of these are examples of energy storage devices or batteries.
Energy storage devices can take a wide variety of forms, such as chemical reac-
tors and kinetic and thermal energy storage devices. Note that each energy storage
device is referred to by a specific name; the word battery, however, is solely used for
electrochemical devices that convert chemical energy into electricity by a process
referred to as galvanic interaction. A galvanic cell is a device that consists of two elec-
trodes, referred to as the anode and the cathode, and an electrolyte solution. Batteries
consist of one or more galvanic cells.
Note that a battery is an electrical storage reservoir and not an electricity-generating
device. Electric charge generation in a battery is a result of chemical interaction,
a process that promotes electric charge flow between the anode and the cathode in the
presence of an electrolyte. The electrogalvanic process that eventually results in
depletion of the anode and cathode plates is resurrected by a recharging process that