For most new energy vehicle owners, charging at the destination should be the most ideal way, so that the trouble of frequent DC charging stations can be avoided. The on-board charger is a key component to complete the conversion of AC power to DC power for the battery, and determines the charging power and efficiency; therefore, the progress of OBC technology has a great relationship with the user charging experience. With the technical development of new energy vehicles and the continuous expansion of the market, the currently common 3.3kW OBC products can no longer meet the needs of OEMs. In the next few years, OBC will undergo qualitative changes in functions and performance.
1. Functional integration
The car is transformed from an internal combustion engine to an electric drive.The meaning is that the engine and the fuel tank are replaced by a motor and a battery, respectively.At the same time, other auxiliary components have been added, such as-adding OBC to charge the battery; adding DCDC charges 12V battery; added electric-driven air-conditioning compressor to replace old mechanical products. In the early electric vehicle models, these newly added components were often applied to the entire vehicle as independent devices, but this increased the cost and volume of the product. Therefore, how to effectively integrate these power components into a whole is the general trend. Of course, there is also a problem of degree control in the process of achieving integration. Insufficient integration results in less significant cost reduction. Too many integrated components result in insufficient product flexibility and it is not easy to become a standardized product. At present, it is one of the more promising solutions to integrate DCDC and heating devices on OBC, and this integration is not only physical integration, but system integration can bring out the largest volume and cost advantages.
2.High power
At present, most OEMs have gradually upgraded the power of OBC products from 3.3kW to 6.6kW, but after reaching 6.6kW, it is already a limit of single-phase AC charging, and the room for further increase is very limited. Therefore, the development of three-phase AC OBC will become a way to achieve high power charging. The three-phase AC OBC generally can reach a charging power of more than 20kW, and the theoretical upper limit can reach 40kW +. At the same time, due to the increase of vehicle electronic equipment, the DCDC power also needs to increase synchronously. In the future, mainstream products are expected to have a capacity of more than 2.5kW to meet OEM demand.
3. Thermal management
The normal working efficiency of OBC and DCDC is generally around 95%. As the overall power performance of the product increases, the heat generation is also more significant. Therefore, water cooling will replace air cooling as a more mainstream thermal management method.
4. Bidirectional inverter
Two-way inverter technology is also one of the future OBC's standard features. It can enable OBC to convert AC to DC to charge the battery, and also convert DC from battery to AC for external power output. Vehicles with two-way inverter technology can realize V2G feedback power to the grid and V2V to charge other electric vehicles.
5.Wireless charging
Wireless charging replaces the conductive charging plug by the electromagnetic wave energy transmission between the charging board and the vehicle receiving board, so it can improve the charging experience very well. Charging methods can also be divided into static charging, semi-dynamic charging, and dynamic charging. At present, the magnetic resonance wireless charging technology adopted by Qualcomm can reach about 90% in charging efficiency and the power has reached 20kW. However, it takes a long time to improve the maturity verification of the technology, the establishment of corresponding standards, and the cost control.
