Battery capacity is so important nowadays, that we decided to dedicate a post to this topic. After all, it expresses what a particular battery can do, over time, which equates to the user’s experience.
We have posted numerous blogs about the factors influencing the capacity of batteries. However this time, we concentrate on the core measure of battery performance itself.
Three Important Drivers of Battery Capacity
A battery is a chemical reaction inside a case. The particular chemistry dictates that battery’s output in terms of usable electricity. But that’s just a theoretical statement. In reality, three factors influence actual performance:
- The ambient temperature outside a battery affects the chemical reaction inside the case.
- The rate at which we discharge a battery affects the total amount of electricity it delivers.
- A battery becomes less efficient as it ages, meaning that its capacity gradually reduces,
Battery capacity is so important for electric vehicle owners these days too, because it dictates how far their vehicle will travel on a single charge. Battery makers express this output in terms of kilowatt hours (kWh).
Let’s imagine a particular battery has a capacity of 100 kWh. This means:
- The battery could deliver the 100 kilowatts in a single hour.
- Or ten kilowatts for ten hours if we gave it a gentler load.
This suggests that we should rather speak of capacity over time, if we want to compare different batteries objectively.
Connecting Batteries in Series and Parallel
We can increment battery output by connecting individual cells together:
- Joining them in parallel increases their capacity so they run longer.
- Doing so in series increases voltage. They can power larger devices.
However, in both instances – and using batteries individually too – there is inevitably some capacity loss due to internal battery operation. True battery capacity is therefore theoretical battery capacity, less that consumed while delivering energy.
More Information
Voltage Pulses Restore Li-Si Capacity
