New energy vehicles are widely used because of their high efficiency and little damage to the environment. However, the existing low-voltage system of new energy vehicles still adopts the low-voltage distribution scheme of traditional internal combustion engine vehicles-that is, it is equipped with 12v lead battery or 12v lithium battery separately. This requires the battery management system to monitor two battery modules (high voltage battery pack and low voltage battery) at the same time; In addition, the lead-acid battery has a short life, which increases the space occupation, increases the weight of new energy vehicles and reduces the power density of the system when installed on new energy vehicles.
In addition, due to the low capacity of 12v low-voltage power supply. After the car is started, the battery must be changed from high voltage to low voltage dc-dc, which greatly increases the system cost.
Prior art solutions to this problem are known, such as:
1) patent name: electric vehicle power supply system, publication number: cn206544473u. This patent proposes a power supply system for electric vehicles. This patent requires the performance of dc-dc module, and requires the battery management system to detect the low voltage system, resulting in a waste of resources.
2) Patent name: an electric vehicle and its power supply system, with publication number: cn 1068090 14a. The patent requires the power device to realize the function of low-voltage power supply, and the system is bulky and costly.
The disadvantages of traditional low-voltage power supply system for new energy vehicles;
(1) Using the same low-voltage battery as the traditional fuel vehicle increases the cost, weight and volume of the new energy vehicle;
(2) The low-voltage battery needs a special battery detection system, which increases the cost of the hardware circuit of the whole vehicle system;
(3) Low-voltage batteries are low in power, which is easy to cause undervoltage when they are stagnant for a long time or in low-voltage open circuit state, so that the whole vehicle cannot be started normally.
(4) The voltage level of low-voltage battery is limited, which can't meet the requirements of high-voltage electrical equipment of automobiles, and requires the performance of high-voltage dc-dc module.
(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)