Trend Analysis of Direct Charging Technology for Electric Vehicles and High Voltage Battery-Pack Design Technology Review

The existing electric vehicle was released with a 400 V battery pack. Assuming that a battery pack of 80 kWh is made, a capacity of 200 Ah should be used for a 400 V battery pack. However, when using 200 Ah, the thickness and power loss of the wiring due to the current increase, and the heat generation loss also increases. To overcome this limitation, vehicles equipped with 800 V battery packs are recently being released. When the 800 V battery pack is mounted, the capacity is reduced by half, that is, 100 Ah, thereby reducing the thickness of the wiring, power, and heat generation loss and improving mileage and performance. Furthermore, the charging time caused by the rise in charging voltage is shortened, and the heat generation is reduced, simplifying the cooling system. Many studies have recently been conducted to increase the battery pack voltage to a high voltage of 800 V or higher. However, various considerations arise when designing a high-voltage battery pack, and this paper examines the voltage specifications of EV chargers and battery packs, analyzes the structure of battery packs that change to high voltages, and discusses high-voltage battery pack design technologies and considerations.