22 Dec 2014

Specific Energy and Power within Batteries

Battery

How does specific energy and specific power differ between primary and rechargeable batteries?

Primary batteries have higher specific energy (ability to hold power) than secondary batteries. The below graph compares the typical gravimetric energy densities of lead acid, NiMH, Li-ion, alkaline, and lithium primary batteries.

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Specific Energy Comparison Chart

The specific power (ability to deliver power) of rechargeable batteries outperforms primary batteries. Furthermore, rechargeable batteries are much more resilient under high loads. The below graph compares the performance of primary and rechargeable batteries under light load (mild discharge) and heavy load (1C).

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Specific Power Comparison of light load vs heavy load for batteries