At least for the 2019 model year, all Kona Electric’s sold in the US will come without a dedicated battery heater while all Canadian versions will include one. Similarly, all US deliveries will come with 5.5 kW PTC direct resistive cabin air heating alone while all Canadian deliveries will include a heat pump (reversible A/C system) to more efficiently assist cabin heating.
These choices implicitly assume that most, or at least a very large fraction, of the US deliveries will go to areas of California that rarely experience severe cold weather. Skipping the heat pump and dedicated battery heater saves money and helps lower the consumer price of the vehicle.
Despite the lack of a dedicated battery heater, the US version of the Kona does have the ability to scavenge heat from the electric motor and power electronics in addition to the heat dissipated by the battery itself to help keep the battery warm when operating in colder conditions.
There is one overall thermal management loop with computer-controlled valves that allow a battery pack sub-loop to either run separately or join together with the coolant that runs through the motor, motor inverter and other power electronics, and the on-board (AC) battery charger.
When a dedicated 2 kW battery heater is available (as in the Canadian version), it is used primarily at sub-zero temperatures (0C or 32F) or when the driver enables an optional “Winter Mode”. The battery heater, if present, is located outside the battery pack and warms the liquid “coolant” just before it enters into the pack.
The winter mode uses extra energy to warm the battery pack to allow for full regenerative braking and quicker fast DC charging. Colder pack temperatures force the battery management system to restrict the amount of power that can recharge the battery in order to avoid damaging the carbon graphite anode. This is an issue common to most lithium ion batteries. Cold temperatures are not much of an issue for power coming out of the battery except under rare and extreme conditions like down near -40 degrees.
Hyundai and Kia are using this new overall battery pack and thermal management design in the 2019 Kia Niro EV and the 2020 Kia Soul EV as well as in the 2019 Hyundai Kona Electric.
According to Kia, the North American version of the 2019 Niro EV will come standard with a heat pump to more efficiently assist with cabin heating and the dedicated battery heater will be an optional feature. In the 2020 Soul EV, both the heat pump and battery heater are listed as optional features.