Vehicle-to-Vehicle (V2V)

Vehicle-to-Vehicle (V2V) technology, in charging contexts, refers to utilizing the traction battery of one electric vehicle (EV) to charge another EV, commonly known as vehicle-to-vehicle mutual charging. As an integral component of the V2X (Vehicle-to-Everything) ecosystem, V2V transforms every EV into a mobile distributed energy storage unit capable of delivering emergency power support to other vehicles, effectively easing range anxiety stemming from gaps in fixed charging infrastructure.

Technical Principles and Implementation Methods

The technical core of V2V charging lies in bidirectional power conversion and coordinated control via the Battery Management System (BMS), enabling regulated power transfer from the donor vehicle's battery to the recipient vehicle's battery. In terms of energy delivery methods, V2V charging is categorised into two primary technical routes.

Wired conductive charging is currently the mainstream solution. By connecting the DC or AC charging ports of both vehicles with dedicated V2V charging cables, direct point-to-point power transfer is established. The donor vehicle must feature reverse-charging capabilities, whilst the recipient vehicle interfaces via BMS to negotiate optimal charging voltage and current parameters. DC V2V charging generally provides higher power outputs—BYD DENZA claims support for up to 60 kW, whilst mobile charging equipment developed by State Grid Shandong Electric Power delivers a maximum output of 20 kW; AC V2V output is constrained by onboard charger capacity, typically hovering around 6 kW.

Wireless V2V charging remains in the cutting-edge research phase, achieving contactless energy transfer via magnetic coupling between vehicle-mounted transmitting and receiving coils. While wireless setups eliminate physical connector compatibility issues, they require precise vehicle positioning with minimal tolerance for longitudinal and lateral parking misalignment. Research indicates that a reconfigurable three-coil topology design can maintain a power transfer efficiency above 86.6% even under 40% lateral offset conditions.

Typical Application Scenarios

V2V charging is predominantly targeted at emergency top-up scenarios. When an EV is stranded due to a flat battery with no charging facilities nearby, a vehicle with sufficient charge can step in to provide emergency rescue. On the streets of Chongqing in 2025, a VOYAH FREE+ successfully rescued a stranded Tesla via its 6 kW AC V2V function, resolving the breakdown. During the 2025 National Day holiday, State Grid Shandong Electric Power integrated service vehicles equipped with V2V mobile charging kits into highway emergency rescue operations, completing 26 vehicle breakdown callouts.

Convoy travel and mobile shared charging represent another practical use case. In remote regions or areas with limited charging amenities, V2V-equipped vehicles can act as mobile charging points to assist accompanying vehicles. XPENG introduced its "1,000 X9 Super Extended-Range Mobile Charging Stations" initiative during the 2026 Spring Festival travel rush, turning X9 range-extender models into mobile power units. Academic research suggests that V2V platforms could match charging demand with available donor vehicles, establishing a peer-to-peer (P2P) mobile charging service model similar to e-hailing.

Economics and Battery Impact

The commercial viability of V2V charging hinges on the electricity peak-to-valley tariff spread. Donor vehicle owners can charge up during off-peak hours at lower rates and supply electricity to other EVs at peak rates during the day, earning an arbitrage margin. Academic models demonstrate that when V2V platforms are run by independent operators, overall EV charging costs for consumers can be reduced, thereby accelerating EV adoption.

Battery longevity remains a paramount concern among owners. Discharging inevitably uses up traction battery cycle life, and deep discharging (below 20% SOC) accelerates capacity degradation. As a result, standard V2V operational recommendations advise setting the discharge cut-off threshold above 20% SOC, while capping charging and discharging rates between 0.1C and 0.2C to minimise battery stress. For range-extended electric vehicles (such as the XPENG X9 Range Extender), since the range extender can fire up to generate electricity whenever needed, main battery degradation pressure is substantially lower, making them particularly well-suited for V2V support duties.

Current Developments and Key Challenges

V2V charging technology is entering early commercialisation, with carmakers such as VOYAH, XPENG, and BYD DENZA rolling out or planning V2V-capable models. Nonetheless, the industry still faces several bottlenecks: high hardware costs—dedicated DC V2V discharging units remain costly, running into several thousand yuan, which hampers widespread adoption; inconsistent cross-brand compatibility—communication protocols and connector standards across OEMs have yet to be unified; and immature business models—frameworks for power pricing, platform dispatch management, and battery wear compensation still require further refinement.