On 12 September 2023, the State Administration for Market Regulation and the National Standardization Administration of China officially approved and released the three key standards for ChaoJi-1, the next-generation DC charging technology using the GB/T communication protocol.
The three documents released are:
- GB/T 18487.1-2023 Electric Vehicle Conductive Charging System Part 1: General Requirements,
- GB/T27930-2023 Digital Communication Protocol between Off-Board Conductive Chargers and Electric Vehicles, and
- GB/T 20234.4-2023 Connecting Devices for Conductive Charging of Electric Vehicles Part 4: High-Power DC Charging Interface.
ChaoJi-1 uses the new, harmonised coupler and compatible charging system with CHAdeMO 3.1, the latest version of CHAdeMO vehicle charging, but operating under the GB/T communication protocol. This version is not only suitable for high, medium and low power charging (up to 1.2MW*), but also considers the current and future adaptability and upgrade capabilities to meet the needs of safe and fast EV charging.
The three standards released this time propose high-power temperature runaway detection technology with Chinese technical characteristics, ensuring the accurate determination of serious faults under high-power charging conditions including:
- a layered and upgradable communication protocol architecture to support future needs and functions that will continue to emerge,
- a new DC control pilot circuit and a safe charging system model, which achieved high level of charging safety and reliability,
- DC charging system compatibility laying the foundation for the future unification of global DC charging technology, as ChaoJi is designed to be compatible with all of existing DC fast charging standards.
The ChaoJi project started in 2018 between China and Japan, later joined by an international collaboration forum. ChaoJi-2, operating under the CHAdeMO protocol, was published in 2020 and the conformance test protocols in 2021. Despite some project delay due to the Covid-19 pandemic and its consequences, prototype testing for the latest version (CHAdeMO 3.1) is starting in Japan.
In China, the State Grid Corporation of China and other operating companies like ATC have constructed over 80 high power** DC chargers with ChaoJi interface. These chargers are located in more than 30 charging sites across Shenzhen, Shanghai, Sichuan, Fujian, Guandong provinces, and along the highway from Beijing to Shanghai. They are being tested by various EV OEMs since 2022.
The harmonised ChaoJi connector has already been published as an IEC PAS (publicly available specification) 63454:2022 (ChaoJi connector standard), and the experts are currently actively discussing vehicle adapters as well as interoperability and safety of such adapters between different DC charging systems in the respective technical committees (SC 23H/PT 62196-7 and TC 69/ahG 17) at the IEC.
*1500V x 800A
**maximum output 500A, highest voltage 1000V, maximum output power 480kW