To meet the requirement of future missions of deep space exploration

a new nuclear battery system

nuclear battery driven by external neutron source

was introduced in this paper.The ratio of power over weight and power output of the nuclear battery calculated with MCNP in a simple model were 4.45 W/g and 9.88 kW

respectively.Compared with radioactive thermal-electric generator(RTG)

this nuclear battery could supply 8 times ratio-power and 3.54 times power output than GPHS-RTG

respectively.Also

the ratio-power and power output of the nuclear battery were calculated in the detail model of GPHS-RTG

and each module could generate 4.3293 W/g of ratio-power and 698.253 W of power output

which are 9.55 times and 10.2 times more than GPHS-RTG

respectively.For a multi-module system

this nuclear battery could generate 6.83 W/g of ratio-power and 22.04 kW of power supply.The advantage of the nuclear battery driven by external neutron source is obvious.