“The development of electric vehicles has entered the fast lane. According to statistics from the Ministry of Commerce, the transaction volume of new energy vehicles in the first three quarters of this year was 2.157 million, with a market penetration rate of 12.4%. The development of intelligent electric vehicles has also ushered in new changes for the BMS system. The automobile BMS system is the communication bridge between the automobile and the battery pack, which can collect, analyze and store real-time data on the temperature, voltage and current of the battery pack, and exchange the collected and analyzed data with external equipment. , To avoid battery overcharging, overdischarging, high temperature and other problems, to ensure the performance of the battery to a certain extent, and extend the life of the battery.
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Author: Li Cheng
The development of electric vehicles has entered the fast lane. According to statistics from the Ministry of Commerce, the transaction volume of new energy vehicles in the first three quarters of this year was 2.157 million, with a market penetration rate of 12.4%. The development of intelligent electric vehicles has also ushered in new changes for the BMS system. The automobile BMS system is the communication bridge between the automobile and the battery pack, which can collect, analyze and store real-time data on the temperature, voltage and current of the battery pack, and exchange the collected and analyzed data with external equipment. , To avoid battery overcharging, overdischarging, high temperature and other problems, to ensure the performance of the battery to a certain extent, and extend the life of the battery.
Image source: ADI
The advantages and disadvantages of wireless BMS systems
At present, automobile BMS systems can be divided into wired BMS systems and wireless BMS systems according to communication methods. Wired BMS system uses CAN bus or iosSPI bus as the form of daisy chain to connect battery pack, slave control chip and master control chip to realize data monitoring and transmission; wireless BMS system connects battery packs in the form of wireless networking , The slave control chip is connected with the main control chip, and the status monitoring and data transmission of the battery pack are completed through wireless communication.
Flexibility. The wireless BMS system uses the wireless network as the connection method to get rid of the shackles of the cable, which allows the battery pack to be flexibly arranged and placed, and according to actual needs, the equipment for real-time battery status detection can be added or deleted at will .
Stability. Wired BMS communicates through cable connection. When cables are used in high-temperature car interiors for a long time, the problem of line aging usually occurs. Once a problem occurs, numerous cables will bring detection and repair. Greater difficulty. The wireless BMS does not have to worry about the aging of the communication cable, and the data transmission rate and delay can be better guaranteed, which improves the ability to perceive the status of the battery pack.
Low cost. The most essential difference between a wireless BMS and a wired BMS system is that it reduces the laying of communication cables, and the consumption of communication cables and connectors will be reduced, which reduces the cost of vehicle manufacturing and BMS to a certain extent. The space occupied by the system.
Insufficiency, because wireless BMS uses wireless communication, which is different from wired BMS internal closed-loop communication, if the safety factor of wireless communication is not high, there may be situations in which the transmitted data information is intercepted.
Although the number of electric vehicles is increasing day by day, consumers still have concerns about the safety and cruising range of electric vehicles. In order to dispel the concerns of consumers, TI and ADI have successively introduced wireless BMS solutions.
TI wireless BMS system solution
In order to improve the endurance of electric vehicles, TI released a wireless BMS solution at the beginning of this year. The solution uses CC2662R-Q1 wireless MCU and BQ79616-Q1 battery monitor to detect battery power, temperature, current, and voltage. , And communicate the data with the main control chip through wireless transmission. The release of the program reduces the laying of communication lines and improves the reliability and efficiency of electric vehicles. It is the first wireless BMS to pass ASIL-D verification.
Image source: TI
SimpleLinkCC2662R-Q1 is a wireless MCU used in automotive BMS systems. The MCU uses Cortex-M4F based on the ARM architecture with a main frequency of -48MHz. CC2662R-Q1 integrates 352KB of programmable Flash, 256KB of ROM, and 8KB of SRAM. CC2662R-Q1 supports wireless communication methods such as 2.4 GHz WiFi, Bluetooth Low Energy, Zigbee, Sub-1 GHz, and is compatible with TI’s proprietary wireless BMS protocol, enabling fast networking. CC2662R-Q1 has the characteristics of low power consumption. The current in the receiving state is 6.9 mA, the working current is 7.3 mA and 9.6 mA when the transmitted signal strength is 0 dBm and 5 dBm, and the standby current is 0.94 μA when in the standby state.
According to TI’s official display, data transmission through TI’s proprietary wireless communication protocol has the characteristics of low delay, high transmission rate (1.2Mbps data throughput), high stability, extremely low data packet loss rate, and PER (
BQ79616-Q1 is a 16-channel automotive battery monitoring chip, mainly used in high-voltage BMS, real-time monitoring of high-voltage batteries. The chip can complete a cycle of battery data detection within 128μs. The BQ79616-Q1 integrates a digital-to-analog converter and a low-pass filter to facilitate the monitoring of the filtered DC voltage, improve the voltage monitoring accuracy, and facilitate the MCU to judge the battery charging status. At the same time, the BQ79616-Q1 also has the functions of battery temperature monitoring and automatic internal balance of the battery. If abnormal battery data is detected at one point, the battery charging and discharging work will be stopped immediately to avoid excessive battery temperature and other fire hazards.
BQ79616-Q1 uses a double-isolated two-way daisy chain with capacitive isolation and transformer isolation to connect the batteries. In terms of interface, the chip has 8 GPIO ports and a dedicated UART interface. The thermal battery of the external circuit can be measured through the GPIO port, and it can communicate with the main controller through the UART interface. The BQ79616-Q1 has an automatic reverse wake-up function. Under normal working conditions, the MCU automatically enters the sleep mode. When an abnormal data is detected, the BQ79616-Q1 will wake up the MCU in the reverse direction. This function is mainly to monitor the battery status even when the car is stopped, and reduce system power consumption.
TI uses a CC2662R-Q1 wireless MCU to connect with multiple BQ79616-Q1 battery monitors to realize a wireless BMS system.
ADI wireless BMS system solution
ADI has launched an electric vehicle wireless BMS system solution earlier, which combines SmartMesh with the LTC6811 battery monitor to realize battery status monitoring and wireless data transmission. This solution improves the reliability of an electric vehicle and reduces the complexity of wiring.
SmartMesh+LTC6811 wireless BMS topology source: ADI
In ADI’s wireless BMS solution, there is no clear indication of the specific model of the SmartMesh wireless MCU. The battery monitor uses the LTC6811.
The LTC6811-1 is a battery pack monitor that can perform high-precision voltage detection on up to 12 groups of batteries in series, with a measurement error of less than 1.2mV, and it only takes 290μs to complete 12-cell battery detection. LTC6811-1 can connect multiple batteries in series, so the chip can complete real-time battery status monitoring in high-voltage battery strings. The chip also has an isoSPI interface, which can realize high-speed remote communication with the device. LTC6811 can connect 12 groups of batteries through a daisy chain to realize the function of multi-channel communication, monitor the battery status, and perform suspend and start operations according to the current status of the battery. The chip uses an isolated power supply.
ADI said that through this combination scheme, more than 90% of cables can be saved, and more than 10% of the battery volume can be reduced, which provides good flexibility for battery layout and disassembly, and the battery life and battery data The measurement accuracy will not be affected.
Author: Li Cheng
The development of electric vehicles has entered the fast lane. According to statistics from the Ministry of Commerce, the transaction volume of new energy vehicles in the first three quarters of this year was 2.157 million, with a market penetration rate of 12.4%. The development of intelligent electric vehicles has also ushered in new changes for the BMS system. The automobile BMS system is the communication bridge between the automobile and the battery pack, which can collect, analyze and store real-time data on the temperature, voltage and current of the battery pack, and exchange the collected and analyzed data with external equipment. , To avoid battery overcharging, overdischarging, high temperature and other problems, to ensure the performance of the battery to a certain extent, and extend the life of the battery.
Image source: ADI
The advantages and disadvantages of wireless BMS systems
At present, automobile BMS systems can be divided into wired BMS systems and wireless BMS systems according to communication methods. Wired BMS system uses CAN bus or iosSPI bus as the form of daisy chain to connect battery pack, slave control chip and master control chip to realize data monitoring and transmission; wireless BMS system connects battery packs in the form of wireless networking , The slave control chip is connected with the main control chip, and the status monitoring and data transmission of the battery pack are completed through wireless communication.
Flexibility. The wireless BMS system uses the wireless network as the connection method to get rid of the shackles of cables, which allows the battery pack to be flexibly arranged and placed, and according to actual needs, the equipment for real-time battery status detection can be added or deleted at will .
Stability. Wired BMS communicates through cable connection. When cables are used in high-temperature car interiors for a long time, the problem of line aging usually occurs. Once a problem occurs, numerous cables will bring detection and repair. Greater difficulty. The wireless BMS does not have to worry about the aging of the communication cable, and the data transmission rate and delay can be better guaranteed, which improves the ability to perceive the status of the battery pack.
Low cost. The most essential difference between a wireless BMS and a wired BMS system is that it reduces the laying of communication cables, and the consumption of communication cables and connectors will be reduced, which reduces the cost of vehicle manufacturing and BMS to a certain extent. The space occupied by the system.
Insufficiency, because wireless BMS uses wireless communication, which is different from wired BMS internal closed-loop communication, if the safety factor of wireless communication is not high, there may be situations in which the transmitted data information is intercepted.
Although the number of electric vehicles is increasing day by day, consumers still have concerns about the safety and cruising range of electric vehicles. In order to dispel the concerns of consumers, TI and ADI have successively introduced wireless BMS solutions.
TI wireless BMS system solution
In order to improve the endurance of electric vehicles, TI released a wireless BMS solution at the beginning of this year. The solution uses CC2662R-Q1 wireless MCU and BQ79616-Q1 battery monitor to detect battery power, temperature, current, and voltage. , And communicate the data with the main control chip through wireless transmission. The release of the program reduces the laying of communication lines and improves the reliability and efficiency of electric vehicles. It is the first wireless BMS to pass ASIL-D verification.
Image source: TI
SimpleLinkCC2662R-Q1 is a wireless MCU used in automotive BMS systems. The MCU uses Cortex-M4F based on the ARM architecture with a main frequency of -48MHz. CC2662R-Q1 integrates 352KB of programmable Flash, 256KB of ROM, and 8KB of SRAM. CC2662R-Q1 supports wireless communication methods such as 2.4 GHz WiFi, Bluetooth Low Energy, Zigbee, Sub-1 GHz, and is compatible with TI’s proprietary wireless BMS protocol, enabling fast networking. CC2662R-Q1 has the characteristics of low power consumption. The current in the receiving state is 6.9 mA, the working current is 7.3 mA and 9.6 mA when the transmitted signal strength is 0 dBm and 5 dBm, and the standby current is 0.94 μA when in the standby state.
According to TI’s official display, data transmission through TI’s proprietary wireless communication protocol has the characteristics of low delay, high transmission rate (1.2Mbps data throughput), high stability, extremely low data packet loss rate, and PER (
BQ79616-Q1 is a 16-channel automotive battery monitoring chip, mainly used in high-voltage BMS, real-time monitoring of high-voltage batteries. The chip can complete a cycle of battery data detection within 128μs. The BQ79616-Q1 integrates a digital-to-analog converter and a low-pass filter to facilitate the monitoring of the filtered DC voltage, improve the voltage monitoring accuracy, and facilitate the MCU to judge the battery charging status. At the same time, the BQ79616-Q1 also has the functions of battery temperature monitoring and automatic internal balance of the battery. If abnormal battery data is detected at one point, the battery charging and discharging work will be stopped immediately to avoid excessive battery temperature and other fire hazards.
BQ79616-Q1 uses a double-isolated two-way daisy chain with capacitive isolation and transformer isolation to connect the batteries. In terms of interface, the chip has 8 GPIO ports and a dedicated UART interface. The thermal battery of the external circuit can be measured through the GPIO port, and it can communicate with the main controller through the UART interface. The BQ79616-Q1 has an automatic reverse wake-up function. Under normal working conditions, the MCU automatically enters the sleep mode. When an abnormal data is detected, the BQ79616-Q1 will wake up the MCU in the reverse direction. This function is mainly to monitor the battery status even when the car is stopped, and reduce system power consumption.
TI uses a CC2662R-Q1 wireless MCU to connect with multiple BQ79616-Q1 battery monitors to realize a wireless BMS system.
ADI wireless BMS system solution
ADI has launched an electric vehicle wireless BMS system solution earlier, which combines SmartMesh with the LTC6811 battery monitor to realize battery status monitoring and wireless data transmission. This solution improves the reliability of an electric vehicle and reduces the complexity of wiring.
SmartMesh+LTC6811 wireless BMS topology source: ADI
In ADI’s wireless BMS solution, there is no clear indication of the specific model of the SmartMesh wireless MCU. The battery monitor uses the LTC6811.
The LTC6811-1 is a battery pack monitor that can perform high-precision voltage detection on up to 12 groups of batteries in series, with a measurement error of less than 1.2mV, and it only takes 290μs to complete 12-cell battery detection. LTC6811-1 can connect multiple batteries in series, so the chip can complete real-time battery status monitoring in high-voltage battery strings. The chip also has an isoSPI interface, which can realize high-speed remote communication with the device. LTC6811 can connect 12 groups of batteries through a daisy chain to realize the function of multi-channel communication, monitor the battery status, and perform suspend and start operations according to the current status of the battery. The chip uses an isolated power supply.
ADI said that through this combination scheme, more than 90% of cables can be saved, and more than 10% of the volume of the battery can be reduced, which provides good flexibility for the layout and disassembly of the battery, and the battery life and battery data The measurement accuracy will not be affected.
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