Transition to Carbon Neutrality in the EV Value Chain (1)Multi-port EV Charger Contributes to Effective Energy Use Solutions in an EV Society

The increased adoption of EVs has resulted in a dramatic increase in energy consumption for EV charging. Therefore, it is important to improve the efficiency of EV fast charging infrastructure to reduce power loss. The DC/DC converter that is the core element of the multi-port EV charger is a dual active bridge conversion type using silicon carbide (SiC) devices and low-loss choke cores. This enables bi-directional power conversion and high conversion efficiency. Through Hitachi's proprietary soft switching control technology, a maximum efficiency of 98.8% and an average efficiency of 98.0% between DC200 and 800 V has been achieved, which is among the best in the industry. This enables high power conversion efficiency to be maintained across the wide range of output voltages and output currents (see Figure 3). The overall efficiency of the multi-port EV charger, including the AC/DC converter, is 95% or higher.

The wide output voltage range of DC150 to 900 V is also a key point. Although the DC450 V class is currently the mainstream of EVs, as DC850 V class EVs become more widespread, the DC450 V and DC850 V classes are expected to coexist in the market during the next five to ten years. It is a huge advantage for one EV charger to be able to support both voltage classes, rather than having to install different devices for each.

The multi-port EV charger is expected to be applied in several systems and solutions. It will enable the building of EV fast charging infrastructure at lower cost and in a more compact space. Examples include EV fast charging infrastructure for en-route charging on highways and in service areas, which has grown significantly in recent years, and large-scale EV parking lots at office buildings and other facilities that are expected to be deployed in the future. The capacity can also be expanded or changed flexibly according to EV charging needs. EV fast charging infrastructure for destination or base charging, like those at buildings, shopping malls, or offices, can be combined with charging and discharging management functions that use various types of information to optimize the overall energy use of the facility through the charging and discharging of EV batteries (see Figure 4).

The issues that must be addressed when deploying EVs and EV fast charging infrastructure vary according to field of business at the deployment location, and a variety of new solutions are expected to appear with the progress of social adoption of EVs. Companies in the Hitachi Group are studying the expansion of businesses that offer effective systems or solutions in each industrial field, and the multi-port EV charger is being commercialized as a product that can be applied as standard when constructing such systems. Since the number of EV charger operation methods and required functions will increase according to the issues faced or solutions needed when deploying EVs, Hitachi plans to systematically add more functions and configurations.

For wide deployment of multi-port EV chargers, it is also important to operate actual facilities and receive the associated feedback. Several demonstrative operations are currently being carried out and prepared. Utilizing large-capacity features, the demonstrative facility for the next-generation ultra-high output charging standard has been built at Hitachi Omika Works and is currently in operation. In addition, from the first half of FY2024, Hitachi Tsuchiura Works will start the operation of Workplace E-Powering (WEP), an initiative to reduce the CO₂ emissions of commuter vehicles by installing EV fast charging infrastructure with the multi-port EV charger in commuter parking lots and adopting EVs as commuter vehicles. In the introduction of WEP, several issues and solutions are actually emerging. Hitachi plans to provide the accumulated know-how to customers who are considering introducing WEP. Preparations are also being made to demonstrate onsite energy management using the charging and discharging of EV batteries.