The rapid growth of electric vehicles is generating a large number of used batteries that still retain significant capacity. These batteries can be effectively reused in photovoltaic energy storage systems, extending their lifecycle by up to 10–24 years. Our project introduces a smart gateway based on the STM32H723ZGT6, enabling seamless communication between EV battery management systems and solar inverters. By combining high-performance processing with robust communication interfaces, the solution ensures reliability and compatibility. This approach significantly reduces costs while promoting sustainability and circular energy use.

The transition to electric mobility has led to an increasing number of batteries reaching the end of their automotive lifecycle. However, these batteries typically retain 70–80% of their original capacity, making them highly suitable for stationary energy storage applications. At the same time, photovoltaic systems require efficient and cost-effective storage solutions to maximize energy usage.

Proposed Solution

We propose a smart gateway that enables the integration and reuse of second-life electric vehicle (EV) batteries in photovoltaic energy systems. The system is built around the high-performance microcontroller STM32H723ZGT6.

The gateway functions as an interface between EV Battery Management Systems (BMS) and solar inverters, ensuring interoperability between otherwise incompatible systems. This is achieved through protocol translation, data acquisition, and the implementation of safety and control mechanisms required for reliable operation.

Technology Overview

The hardware architecture integrates a high-performance microcontroller from the STM32 family, industrial-grade communication interfaces based on CAN and CAN-FD standards, and robust transceivers provided by Texas Instruments. The printed circuit board design is optimized to ensure electrical stability, noise immunity, and long-term reliability in demanding operating environments.

This architecture enables high reliability under real-world conditions, scalable integration across multiple battery chemistries and configurations, and real-time monitoring and control of system parameters.

Key Advantages

From an environmental perspective, the solution contributes to reducing electronic waste, extending the operational lifetime of lithium-ion batteries, and supporting circular economy principles.

From an economic standpoint, it significantly lowers the cost of energy storage compared to new battery systems, enables faster return on investment, and increases accessibility for both residential and industrial applications.

From a technical perspective, the system supports an estimated additional operational lifetime of 10 to 24 years, ensures high reliability through industrial-grade components, and allows flexible integration with a wide range of inverter platforms.

Impact and Future Potential

The proposed solution facilitates the broader adoption of renewable energy by providing a cost-effective and sustainable storage alternative. It also contributes to the development of the second-life battery market and supports increased energy independence at both residential and industrial scales.

Conclusion

This project represents a convergence of advanced embedded systems engineering and sustainable energy practices. By enabling the reuse of EV batteries within photovoltaic systems, it reduces costs, minimizes environmental impact, and contributes to the development of a more efficient and resilient energy ecosystem.