The Prius That Shook.. - VFAQ Prius Site

A difficult heat problem
The improved prototype battery was installed under the
floor of the vehicle, and tests were run. Daytime
temperature began to rise in May, and some days were as hot
as midsummer days. Due to the outside temperature, the
battery started to produce more heat because the cooling
system was not yet complete. Perhaps due to the heat, the
battery's output only reached 10 to 15 kiloWatts. When the
car was forced to continue running, the indicator for battery
malfunction lit up, and the car stopped.
There were two issues to the heat problem. The first
was whether the battery should be designed to be more heat-
resistant to prevent power loss. The second was how the
battery could be cooled from the outside. There were many
possible causes of heat, but the group could not make sense
out of all the possibilities and could not find a solution.
A hybrid vehicle switches through various driving modes
very frequently. It can run on the engine alone, the electric
motor can assist the engine, or the electric motor alone can
move the car. It is necessary to estimate and control how
much electricity is discharged from the battery for every
mode and how much electricity is left in the battery.
In real life, the car must go up a long uphill in the middle
of summer, or go through snow or ice. It is
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