Vehicle body rear structure of electric vehicle

1. A vehicle body rear structure of an electric vehicle, the vehicle body rear structure comprising:

a high-voltage device arranged in a rear portion of the electric vehicle, wherein the high-voltage device is included in an electric powertrain of the electric vehicle or is electrically connected to the electric powertrain, and the high-voltage device is operable on a voltage over AC 30 or DC 60 volts;

a low-voltage device arranged rearward of the high-voltage device at a same height level as the high-voltage device, wherein the low-voltage device is operable at a voltage lower than AC 30 or DC 60 volts; and

a crossmember passing through between the high-voltage device and the low-voltage device, wherein

the crossmember is a polygonal tube including an upper plate, a lower plate, a front plate, and a rear plate, and

each of the lower plate and the front plate is thicker than the upper plate and the rear plate.

2. The vehicle body rear structure of claim 1 , wherein the crossmember is connected to a pair of rear side members extending in a vehicle front-rear direction between the rear side members.

3. The vehicle body rear structure of claim 1 , wherein the low-voltage device is positioned lower than an upper surface of the crossmember.

4. The vehicle body rear structure of claim 1 , wherein the low-voltage device is positioned higher than a lower surface of the crossmember.

5. The vehicle body rear structure of claim 1 , wherein a center of gravity of the low-voltage device is positioned at a same height level as the crossmember.

6. The vehicle body rear structure of claim 1 , wherein

the front plate is inclined such that an upper end of the front plate is positioned forward of a lower end of the front plate, and

the rear plate is inclined such that an upper end of the rear plate is positioned forward of a lower end of the rear plate.

7. A vehicle body rear structure of an electric vehicle, the vehicle body rear structure comprising:

a high-voltage device arranged in a rear portion of the electric vehicle, wherein the high-voltage device is included in an electric powertrain of the electric vehicle or is electrically connected to the electric powertrain, and the high-voltage device is operable on a voltage over AC 30 or DC 60 volts;

a low-voltage device arranged rearward of the high-voltage device at a same height level as the high-voltage device, wherein the low-voltage device is operable at a voltage lower than AC 30 or DC 60 volts; and

a crossmember passing through between the high-voltage device and the low-voltage device, wherein

the crossmember is a polygonal tube including an upper plate, a lower plate, a front plate, and a rear plate,

the front plate is inclined such that an upper end of the front plate is positioned forward of a lower end of the front plate, and

the rear plate is inclined such that an upper end of the rear plate is positioned forward of a lower end of the rear plate.

8. The vehicle body rear structure of claim 7 , wherein the crossmember is connected to a pair of rear side members extending in a vehicle front-rear direction between the rear side members.

9. The vehicle body rear structure of claim 7 , wherein the low-voltage device is positioned lower than an upper surface of the crossmember.

10. The vehicle body rear structure of claim 7 , wherein the low-voltage device is positioned higher than a lower surface of the crossmember.

11. The vehicle body rear structure of claim 7 , wherein a center of gravity of the low-voltage device is positioned at a same height level as the crossmember.