Abstract:

The electrical and thermal performances of power lithium-ion batteries used in electric vehicles were
experimentally investigated to guarantee the power lithium ion battery operate safely, reliably and efficiently.
A charge and discharge tester and a temperature / humidity recorder were used to control the various rate of
discharge at the arrange of 1C~3C (50~150 A) for a kind of 3.2 V/50 Ah lithium-ion power batteries commercial
applied. The test results show that the operator voltage platform between battery two ends is going to lower
with the output energy decreasing and the battery surface temperatures increasing when the discharged rate
increases. The temperature at the lithium-ion battery surface exceeds the temperature limit for battery safely
operating when the battery discharged rate up to 3C rate (or 150 A). Therefore, being equipped with cooling
device is necessary for battery to ensure battery operate safely and efficiently. A group of empirical formulae
was fitted for the battery transient heat production battery at various battery discharge rate. The formulas can be
used to design and select auxiliary cooling devices for power lithium-ion batteries.

Key words: electric vehicles, lithium-ion power battery, thermal performances, rate capability, transient heat generation rate, auxiliary cooling devices