Autonomous vehicle route planning

1. An autonomous vehicle comprising:

an electric powertrain; and

a controller programmed to

autonomously operate the powertrain to propel the vehicle along a segment of a route according to a predetermined first speed profile that has a constant vehicle speed responsive to predicted battery temperatures for the segment not exceeding a threshold, and

autonomously operate the powertrain to propel the vehicle along the segment according to a predetermined second speed profile that has multiple vehicle speeds responsive to the predicted battery temperatures exceeding the threshold such that actual battery temperatures remain below the threshold for the segment.

2. The autonomous vehicle of claim 1 , wherein the segment includes at least one portion with increasing road grade and at least one portion with decreasing road grade.

3. The autonomous vehicle of claim 2 , wherein the second speed profile has a greater vehicle speed for the portion with decreasing road grade, and has a lesser vehicle speed for the portion with increasing road grade compared to the first speed profile.

4. The autonomous vehicle of claim 1 , wherein the electric powertrain includes a traction battery and an electric machine configured to receive power from the traction battery, and further comprising a battery-cooling system.

5. The autonomous vehicle of claim 4 , wherein the second speed profile is based on a heat-convection coefficient of the battery-cooling system.

6. The autonomous vehicle of claim 4 , wherein the second speed profile is derived from comparing multiple energy-consumption values of the battery-cooling system and wherein each energy-consumption value corresponds to a different heat-convection coefficient of the battery-cooling system.

7. The autonomous vehicle of claim 4 , wherein the second speed profile is predicted to generate a lesser aggregate value of heat generated by the traction battery over the route than an aggregate value of cooling capacity of the battery-cooling system over the route.

8. The autonomous vehicle of claim 7 , wherein the first speed profile is predicted to generate a greater aggregate value of heat generated by the traction battery over the segment than the aggregate value of heat generated by the traction battery by the second speed profile.

9. The autonomous vehicle of claim 1 , wherein the second speed profile is based on a predicted heat generated by a traction battery.

10. An autonomous vehicle comprising:

an electric powertrain including an electric machine and a traction battery; and

a controller programmed to command power to the electric machine to propel the vehicle along a segment of a route according to a predetermined speed profile that is derived from a predicted heat generation of the traction battery for the segment such that actual temperatures of the battery remain below a temperature threshold for the segment.

11. The autonomous vehicle of claim 10 , wherein the predetermined speed profile is further derived from power limits of the traction battery.

12. The autonomous vehicle of claim 10 , wherein the segment includes at least one portion with increasing road grade and at least one portion with decreasing road grade, and the speed profile includes decreasing speed for the portion with increasing road grade, and increasing speed for the portion with decreasing road grade.

13. The autonomous vehicle of claim 10 further comprising a battery-cooling system, wherein the speed profile is further derived from comparing multiple energy-consumption values of the battery-cooling system, wherein each of the energy-consumption values corresponds to a different heat-convection coefficient of the battery-cooling system.

14. The autonomous vehicle of claim 10 , wherein the speed profile is predicted to generate a lesser aggregate value of heat generated by the traction battery over the segment than an aggregate value of cooling capacity of the battery-cooling system over the segment.

15. An autonomous vehicle comprising:

a traction battery;

an electric powertrain powered by the traction battery; and

a controller programmed to:

generate a plurality of speed profiles for a route, wherein the speed profiles include propulsion commands for autonomously operating the electric powertrain to propel the vehicle,

determine a power capability of the traction battery,

discard ones of the speed profiles that have a power demand of the traction battery exceeding the power capability,

store, in a set, ones of the speed profiles that have a power demand of the traction battery less than the power capability,

for each of the speed profiles in the set, determine an associated predicted heat generation of the traction battery and an associated cooling profile for the traction battery,

select an optimum one of the speed profiles based on the predicted heat generation and the cooling profile, and command power to the electric powertrain according to the optimum one of the speed profiles.

16. The autonomous vehicle of claim 15 , wherein the select the optimum one of the speed profiles includes (i) for each of the speed profiles in the set, summing a first term based on the predicted heat generation and a second term based on the cooling profile to generate a plurality of values and (ii) selecting a one of the speed profiles having a smallest of the values as the optimum speed profile.

17. The autonomous vehicle of claim 15 , wherein the electric powertrain includes an electric machine configured to receive power from the traction battery, and further comprising a battery-cooling system.

18. The autonomous vehicle of claim 17 , wherein the optimum one of the speed profiles has an aggregate value of the heat generated by the traction battery over the route that is less than an aggregate value of cooling capacity of the battery-cooling system over the route.