Systematic Design of Adaptive Connectors Based on Shape Memory Alloys for Electrical Vehicles

Abstract Fast charging of electric vehicles (EVs) plays a critical role in the adoption of EVs and thereby in the transition from fossil fuels to renewable energy sources in the transportation sector. However, there are significant limitations to the maximum electrical power that can be transferred during the charging process. One of the biggest challenges is the high electrical contact resistance (ECR) between the charging plug and the vehicle inlet, which leads to significant waste heat generation and associated energy loss. These factors not only affect the efficiency of the charging process, but also carry the risk of damage to the connector system and the EV. In response to these challenges, this paper proposes a novel approach for an adaptive connector based on thermal shape memory alloys (SMAs). The proposed adaptive connector is designed to increase contact forces only during the charging process, effectively mitigating ECR while ensuring compatibility with existing charging infrastructure. As a result, this technology promises to unlock higher transmission power capabilities and significantly reduce charging times. An integral aspect of this proposed solution is the inherent ability of SMA-based connectors to self-activate in response to the initial high ECR, generating joule heating that triggers the SMA actuator. This eliminates the need for additional power or active actuator control, allowing for a streamlined and energy efficient charging process. This paper outlines a systematic design framework for the implementation of adaptive connectors, including comprehensive integration of SMA actuators and meticulous optimization strategies tailored to ensure efficient and reliable fast charging of EVs. Evaluation and validation of the system’s effectiveness is underway through trials using combined charging systems (CCS) Type 2 connectors tailored for High Power Charging (HPC) applications, which can accommodate charging powers of up to 500kW. Through these concerted efforts, this research aims to drive the evolution of fast charging technology, catalyzing the widespread adoption of electric vehicles and accelerating the transition to sustainable transportation solutions.