Is a Hi-Tech battery right for you?
An area that I think is often overlooked is the detailed selection of the battery to power equipment, or more precisely, the chemistry of the battery. There is the understandable pressure to select a battery that has an image in keeping with the hi-tech nature of the equipment it is intended to power. This tends to lure designers into selecting a lithium battery because of the draw and aura of having a battery perceived as hi-tech, no doubt with a little persuasion from a marketing angle too!
Making the right battery choice
Is the tendency to specify a lithium battery founded on good judgement and fact? As with most things there are pros and cons with whatever approach is taken. Sometimes the choice may not even rest with the battery performance alone, weight volume and even ease of transport are examples of factors that need to be considered. Additionally, variations in the way different battery types respond to increased loads and the operating temperature will mean that a battery that seems ideal at one end of the performance envelope is woefully inadequate at the other.
Key Parameters Check
As a quick comparison I have looked at three different primary (non-rechargeable) battery chemistries across a range of parameters, comparisons based on the same cell size.
Cell Type A
Highest energy cell
Best Operating Temperature Range
Poor rate capability (typically a few 10’s of mA, low 100’s under favourable conditions)
Start up delay needs managing in certain applications
Cell Type B
Highest Power Density
Good operating temperature range
High discharge currents (Amps) maintained down to -30°C
Minimal start up delay
Cell Type C – Low tech option
Significantly lower cost (around 20% of Type A)
No Transportation Issues
No ‘start up’ delay
Good rate capability (100’s of mA)
Low energy density
Not much performance below -5°C
Even from this relatively short comparison it can be seen that if weight and volume are not a problem, but cost and transportation are, the ‘low tech’ route really is worth considering.
Taking the correct guidance
Of course in a short blog like this it would be difficult to examine all the performance levels and present them clearly. Each new design will have its own key drivers which may push the battery selection in a different direction. That is why it is vitally important to capture all the requirements that the battery will need to meet in your design, prioritise these, and then match different battery types to them. Calling on the expertise offered by an independent expert who can examine options from a wide variety of sources, can ultimately save you time and money in your new development process.