(A) Using the Specified Maximum Output Power for the NiMH$19.6$

Question

Examlex · Accepted Answer

The Answer is (a) The specific power of NiMH batteries, from the text, is 800 W/kg. The General Motors produces

102 \mathrm {~kW}

so the battery mass is

( 102 \mathrm {~kW} ) / ( 0.8 \mathrm {~kW} / \mathrm { kg } ) = 128.5 \mathrm {~kg}

The Toyota produces

50 \mathrm {~kW}

for a battery mass of

( 50 \mathrm {~kW} ) / ( 0.8 \mathrm {~kW} / \mathrm { kg } ) = 62.5 \mathrm {~kg}

(b) The specific energy for a NiMH battery is

0.28 \mathrm { MJ } / \mathrm { kg }

. The total battery capacity for the General Motors is

( 128.5 \mathrm {~kg} ) imes ( 0.28 \mathrm { MJ } / \mathrm { kg } ) = 36.0 \mathrm { MJ }

For the stated range of

260 \mathrm {~kg}

then the energy per

\mathrm { km }

is

( 36 \mathrm { MJ } ) / ( 260 \mathrm {~km} ) = 0.14 \mathrm { MJ } / \mathrm { km }

The total battery capacity for the Toyota is

( 62.5 \mathrm {~kg} ) imes ( 0.28 \mathrm { MJ } / \mathrm { kg } ) = 17.5 \mathrm { MJ }

For the stated range of

160 \mathrm {~km}

the energy per

\mathrm { km }

is

( 17.5 \mathrm { MJ } ) / ( 160 \mathrm {~km} ) = 0.11 \mathrm { MJ } / \mathrm { km }

(A) Using the Specified Maximum Output Power for the NiMH $19.6$