Building a Private Bitcoin-Based Payment Network Among Electric Vehicles and Charging Stations

Mass penetration and market dominance of Electric Vehicles (EVs) are expected in the upcoming years. Due to their frequent charging needs, not only public and private charging stations are being built, but also V2V charging options are considered. This forms a charging network with various suppliers and EV customers which can communicate to schedule charging operations. While an app can be designed to develop matching algorithms for charging schedules, the system also needs a convenient payment method that will enable privacy-preserving transactions among the suppliers and EVs. In this paper, we adopt a Bitcoin-based payment system for the EV charging network payments. However, Bitcoin has a transaction fee which would be comparable to the price of the charging service most of the time and thus may not be attractive to users. High transaction fees can be eliminated by building a payment network in parallel to main ledger, with permission and signatures. In this paper, we design and implement such a network among charging stations and mobile EVs with flow, connectivity and fairness constraints, and demonstrate results for the feasibility of the scheme under different circumstances. More specifically, we propose a payment network optimization model for determining payment channels among charging stations. We present numerical results on the characteristics of the network model by using realistic use cases.

I. Introduction

The popularity of electric vehicles (EVs) has been increasing since they can transform the modern transportation and energy systems with a reduced foreign-oil dependence and improved urban air quality. They can promote adoption of intermittent renewable energy sources by acting as energy storage systems [1] during the periods of strong wind or sun [2]. EVs can also help in realizing the foundation of smart cities of the future by injecting energy to the grid during periods of reduced production to balance demand. Due to such potential, many automotive companies have rolled out EVs as part of their product lines [3], [4]. As a result, mass penetration and market dominance of EVs are expected in the upcoming years, particularly with reduced production costs.