Page 82 - Lindens Handbook of Batteries

CHAPTER 3

FACTORS AFFECTING BATTERY
PERFORMANCE

David Linden

3.1 GENERAL CHARACTERISTICS

The specific energy of a number of battery systems is listed in Table 1.2. These values are based
on optimal designs and discharge conditions. While these values can be helpful to characterize the
energy output of each battery system, the performance of the battery may be significantly different
under actual conditions of use, particularly if the battery is discharged under more stringent condi-
tions than those under which it was characterized. The performance of the battery under the specific
conditions of use should be obtained before any final comparisons or judgments are made.

3.2 FACTORS AFFECTING BATTERY PERFORMANCE

Many factors influence the operational characteristics, capacity, energy output, and performance of
a battery. The effect of these factors on battery performance is discussed in this section. It should
be noted that because of the many possible interactions, these effects can be presented only as gen-
eralizations and that the influence of each factor is usually greater under the more stringent operat-
ing conditions. For example, the effect of storage is more pronounced not only with high storage
temperatures and long storage periods, but also under more severe conditions of discharge following
storage. After a given storage period, the observed loss of capacity (compared with a fresh battery)
will usually be greater under heavy discharge loads than under light discharge loads. Similarly, the
observed loss of capacity at low temperatures (compared with normal temperature discharges) will
be greater at heavy than at light or moderate discharge loads. Specifications and standards for batter-
ies usually list the specific test or operational conditions on which the standards are based because
of the influence of these conditions on battery performance.
Furthermore it should be noted that even within a given cell or battery design, there will be per-
formance differences from manufacturer to manufacturer and between different versions of the same
battery (such as standard, heavy-duty, or premium). There are also performance variables within a
production lot, and from production lot to production lot, that are inherent in any manufacturing
process. The extent of the variability depends on the process controls as well as on the application
and use of the battery. Manufacturers’ data should be consulted to obtain specific performance
characteristics.

3.1