Computationally Efficient Approach for Preheating of Battery Electric Vehicles before Fast Charging in Cold Climates

TL;DR

This paper presents a simple, low-complexity control algorithm for preheating electric vehicle batteries in cold climates, reducing energy use while preventing performance degradation before fast charging.

Contribution

A computationally efficient preheating control method is developed that mimics optimal behavior without solving complex nonlinear programs, suitable for vehicle control units.

Findings

The proposed algorithm increases energy consumption by only 1Wh.

It effectively prevents battery performance loss in cold conditions.

The method is simple enough for real-time implementation in vehicle systems.

Abstract

This paper investigates battery preheating before fast charging, for a battery electric vehicle (BEV) driving in a cold climate. To prevent the battery from performance degradation at low temperatures, a thermal management (TM) system has been considered, including a high-voltage coolant heater (HVCH) for the battery and cabin compartment heating. Accordingly, an optimal control problem (OCP) has been formulated in the form of a nonlinear program (NLP), aiming at minimising the total energy consumption of the battery. The main focus here is to develop a computationally efficient approach, mimicking the optimal preheating behavior without a noticeable increase in the total energy consumption. The proposed algorithm is simple enough to be implemented in a low-level electronic control unit of the vehicle, by eliminating the need for solving the full NLP in the cost of only 1Wh increase in the total energy consumption.