In recent years, increasing numbers of new and existing car makers are involved in electric vehicle development, as electric vehicles have a good potential of replacing the internal combustion engine vehicles. The most important power source for electric vehicles is the lithium battery. Good management of the lithium battery is the key to the successful development of electric vehicles.
Electric vehicles are the rising stars of the car industry development. In fact, in the history of car development, electric vehicles emerged earlier than the internal combustion engine vehicles. However, as the battery power technology was not matured yet then, electric vehicles were replaced instead by internal combustion engine cars along with the exploration of petroleum and the rapid development of the internal combustion engine. Up to now, the performance of current electric vehicles is no less than that of the internal combustion engine cars. Some electric powered sports cars even have better performance than internal combustion engine cars. This is because the electric motor of an electric vehicle has better torque performance than a traditional car, coupled with usually a lighter body, providing good acceleration capability.
However, the cruising endurance of an electric vehicle is short and the charging time is long, which make many potential users hesitant in buying them. To improve these situations, it depends on a good lithium battery management system (BMS) for cars to improve the electric vehicle performance.
The main functions of the BMS are to check each parameter of the electric vehicle battery, which includes single cell voltage, total voltage, current, temperature, etc. Meanwhile, by collecting data from the analog front end, the system can estimate the state of charge (SOC), state of health (SOH) and state of power (SOP) for the battery and keep the battery in balance. A good BMS will not only increase the car’s cruise endurance and battery service life, but also can ensure the system will not overheat and cause a failure.
The framework of the BMS and the technology critical elements include the bottom tier of the detection and recording of temperature and voltage of the cell, which will be sent to the next upper tier of the battery monitor unit (BMU). In addition to monitoring the cell state, the BMU’s another important function is to actively /passively keep the battery in balance for compensating a battery’s slight mismatching and for effectively extending the battery’s service life. The protocols such as CAN, SPI or UART can be used to send relevant information between the battery module management units. Moreover, they can be sent to a further upper tier of the battery control unit (BCU). The BCU will in turn, based on this information, perform its control strategies on battery management, alert and safety protection, thus extending the battery’s service life and safety.
Arrow ESC launches the BMS, which utilizes MC33771+MC33664 solutions from NXP. MC33771 was introduced by the NXP Company, which uses lithium battery management chips with the 14-channel battery sampling capability and ASIL-C certification, and has integrated the metal oxide semiconductor (MOS) up to 300mA in the passive current balance management. It also supports under-/over-voltage, over-temperature, open-circuit and short-circuit failure detection and has the highly accurate integrated coulometer function for checking the voltage and current. MC33771 supports 7 ways of temperature sampling input and hot plugging. MC33664 is a high-speed transceiver capable of isolating the network, and supports 2.0MHz isolated differential signal (TPL) communication as well as 4.0MHz SPI communication, providing communications between MC33771 and the main control unit (MCU). The two units of the Battery Management Unit (BMU) and Battery Control Unit (BCU), plus the processor (MCU) of the BMU, all use NXP's MKEAZ128MLK4. The processor (MCU) of the BCU uses NXP's MPC5744P ASIL-D class chip from the NXP Company. Power is supplied by the FS6522 ASIL-D class chip with functional safety and the CAN transceiver.
Arrow ESC’s Lithium Battery Management System uses the traditional CAN distributed architecture that supports up to 15 MC33771s in cascade connection. Main semiconductor devices all use NXP chips, such as MCU, Power SBC, AFE, CAN transceiver and other automobile-grade ICs. Each level of BMU supports the wide working voltage range of 9.6V-61.6V, directly powered by the battery unit. MC33771 can manage 8-14 battery units. With its two safety targets and 46 safety mechanisms, MC33771 can provide customers with the design reference.
Arrow ESC launches the lithium BMS that can provide an excellent solution for car makers who intend to develop electric vehicles. This solution can reduce the product development cost, and speed up the product development. It is worth further understanding by relevant business owners.
SHOP NXP'S MC33771
SHOP NXP'S MC33771