Ambient temperature plays a significant role in the variability of the electric range of plug-in hybrid electric vehicles (PHEVs). This variability is mainly due to the increased energy demand for heating or cooling the cabin, and the temperature-dependent effects on battery chemistry and performance.
Impact of Ambient Temperature on PHEV Electric Range
- Cold Temperatures Reduce Electric Range:
At low ambient temperatures, the electric range of PHEVs decreases noticeably. This happens because cold conditions require more energy for cabin heating, which draws from the battery and reduces the energy available for propulsion. Additionally, battery chemistry is adversely affected by cold, lowering usable battery capacity and power output. For example, tests showed a PHEV’s all-electric range (AER) dropping by approximately 25% when the ambient temperature decreased from 23 °C to −7 °C with heating in use (from ~20 km to ~15 km). The cold also leads to increased exhaust emissions due to more frequent use of the combustion engine as electric assistance declines. - Heating and Air Conditioning Systems Consume Significant Energy:
Both heating and cooling systems use electric power, which further reduces the electric driving range. At warmer ambient temperatures (e.g., 35 °C), use of air conditioning can increase energy consumption and reduce range, although the magnitude is generally less severe than the effect of cold temperatures. For example, starting a fully charged battery at 23 °C versus 35 °C with air conditioning showed increased CO2 emissions in the warmer case because of the additional load from climate control, reducing electric range and increasing fuel use. - Battery Chemistry Effects:
Battery performance degrades in very cold weather, limiting the available energy and reducing electric driving distance. The battery’s internal resistance increases in cold, which reduces efficiency and maximum power delivery. This is a secondary cause of range loss beyond the HVAC energy consumption. - Optimal Temperature for Maximum Range:
The most efficient electric range for PHEVs and EVs tends to occur around mild ambient temperatures near 20-23 °C (around 70 °F). At this range, HVAC load is minimal, and battery chemistry operates efficiently. Deviations from this ideal temperature lead to range losses. For instance, EVs (and similarly PHEVs) perform best around 70 °F, with range dropping significantly as temperature moves toward freezing or extremely hot conditions.
Summary
Ambient temperature influences PHEV electric range primarily through:
- Increased electric load from heating in cold or air conditioning in heat, which consumes battery energy otherwise used for driving.
- Reduced battery efficiency and usable capacity at low temperatures that limit electric propulsion.
- Resulting decrease in electric range by roughly 25% or more in cold conditions and a smaller but noticeable decrease in hot conditions.
Understanding this variability is important for users to manage expectations around PHEV electric-only driving distances across seasons and climates.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-role-does-ambient-temperature-play-in-the-variability-of-phev-electric-range/
