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Talking about several classic BMS system scheme diagrams
Release time:2020/8/4 11:47:08
The battery management system (BMS) is a new product born in this century. Because the electrochemical reaction is difficult to control and the material performance changes in the process are elusive, such a housekeeper is needed to constantly monitor, adjust, and limit battery packs. To ensure the safety of use, its main functions are:
1. Monitor the battery status in real time. By detecting the external characteristic parameters of the battery (such as voltage, current, temperature, etc.) and using appropriate algorithms, the internal state of the battery (such as capacity and SOC, etc.) can be estimated and monitored. This is the basis and key to the effective operation of the battery management system;
2. Perform thermal management, battery balance management, charge and discharge management, fault alarm, etc. after correctly acquiring the battery status;
3. Establish a communication bus to exchange data with the display system, vehicle controller and charger.
The battery management system (BMS) is mainly divided into two parts. The first part is the front-end analog measurement protection circuit (AFE), including the battery voltage conversion and measurement circuit, the battery balance drive circuit, the switch drive circuit, the current measurement, and the communication circuit; The second part is the back-end data processing module, which is based on the front-end calculations such as voltage, current, and temperature, and returns the necessary information to the system through the communication interface for control.
The current battery management system (BMS) product design solutions are monopolized by foreign manufacturers, and they all use battery management ICs provided by foreign semiconductor IC manufacturers and design with their application solutions as a reference.
Maxim, Linear Technology (acquired by ADI), Intersil, TI, ADI, and NXP are the main solution providers.
Maxim solution
Maxim series products construct a complete 12-cell battery monitoring solution. Maxim's battery monitors (MAX172XX series), battery protectors (DS277X series) and battery selectors (MAX1538) can effectively extend battery life and ensure a safe and reliable system jobs. Its series of high-voltage devices help realize the transition to low-carbon energy solutions. The devices integrate advanced functions to reduce the size, cost and design complexity of the battery management system. Consumers can get higher system reliability, longer battery life and faster time to market.
Features of the Maxim solution:
1. Greatly simplifies the design of multi-cell battery packs. The device contains 12 measurement channels and uses a capacitively isolated stepped SMBus communication bus, which greatly reduces the number of components and reduces costs. This unique architecture allows up to 31 devices to be connected to a series battery pack to monitor up to 372 cells. The capacitance-based interface provides extremely low-cost isolation between battery packs and eliminates cascading electrical failures.
2. With excellent performance, Maxim's high-voltage, small-size BiCMOS process has the industry's highest withstand voltage (80V), excellent ESD protection (±2kV, human body model), and hot-swappable function, ensuring compliance in a wide operating temperature range AEC-Q100 standard maintains high reliability.
3. The analog front end includes a 12-channel voltage measurement data acquisition system and a set of high-voltage, fault-tolerant switch inputs. The high-speed, 12-bit ADC digitizes the battery voltage under test. Two-phase scanning technology is adopted to obtain battery measurement data and correct errors. This technology can measure battery voltage at the same time, and complete the voltage measurement and sampling of all 120 batteries within 10 μs, ensuring excellent accuracy even in noisy systems. The error is less than ±0.25% in the entire battery nominal operating temperature range, and the error is less than ±20mV in the entire AEC-Q100 Class 2 temperature range.
4. The power consumption can be reduced by 10 times (the current is 100μA in working mode) to extend the battery life. The unique built-in shutdown circuit reduces the power consumption to an extremely low level (leakage current is only 1μA), so that the battery can be stored for several years without loss of battery power.
5. For the optimized design of automotive applications, the Maxim solution has internal configuration and self-diagnostic modes, which are essential for the work of the safety monitoring system, and can ensure trouble-free operation in harsh environments with magnetic fields and transient noise. Maxim uses a variety of methods such as high current injection, stripline, and in-vehicle monitoring to conduct comprehensive tests on ICs to ensure reliable operation in battery packs with strong transient electrical signals and magnetic field interference. The device has the pin open circuit and short circuit fault detection functions specified by the FMEA standard, and can handle internal circuit faults.
Maxim scheme diagram
Linear Technology Solution
Linear Technology's series of multi-cell and high-voltage battery pack monitors are complete battery monitoring ICs. They have built-in 12-bit ADCs, accurate voltage references, a high-voltage input multiplexer and a serial interface. These devices can be connected in series (without using optocouplers or opto-isolators) to monitor each cell in a long series connection.
Linear Technology's LTC6804-1 / LTC6804-2-multi-cell battery pack monitors, designed for automotive and transportation applications, specific package AEC-Q100 data.
Program features:
1. It can measure the voltage of up to 12 batteries in series, and the stackable architecture can support hundreds of batteries
2. Built-in isoSPITM interface: 1Mbps isolated serial communication, using a single twisted pair, up to 100 meters, low EMI sensitivity and radiation
3. 1.2mV maximum total measurement error, can complete the measurement of all batteries in the system within 290μs: synchronous voltage and current measurement
4. 16-bit incremental accumulation (ΔΣ) ADC with frequency programmable third-order noise filter
5. System engineering design for ISO26262 standard, passive battery charge balance with programmable timer
6. 5 universal digital I/O or analog inputs: temperature or other sensor inputs, configurable as an I2C or SPI master
7. 4μA sleep mode power supply current
Linear Technology solution application diagram
Intersil solution
Intersi's ISL78600 Li-ion Battery Manager IC supervises up to 12 batteries connected in series. Provides accurate monitoring, battery balancing and extensive system diagnostic functions. Three battery balance modes are combined-manual balance mode, timing balance mode and automatic balance mode. When the automatic balance mode is terminated, it means that the value of the charge transfer specified by the host microcontroller has reached the balance.
Intersil's HEV/EV solution ensures that customers comply with ISO26262 (ASIL) specifications and prevent battery pack failures. The solution also provides built-in fault detection for all major internal functions, and can detect external faults such as line interruptions, overvoltage and undervoltage, as well as temperature and battery balance faults.
The Intersil battery management system provides the high accuracy required for accurate state-of-charge measurement, thereby extending vehicle driving range and high-performance lithium-ion battery life. To do this, each chip uses a 14-bit temperature-compensated data converter that can scan 12 channels in 250 microseconds.
In order to achieve the highest possible reliability of communication within the system, Intersil battery manager uses a high noise immunity and transient fault-tolerant communication mechanism. This fully differential daisy-chain architecture allows multiple battery packs to be stacked together using low-cost twisted pairs, while preventing hot swapping and high transient voltages. The advantages of the Intersil solution can significantly reduce the overall cost of the battery management system.
The ISL78600 allows easy connection to a microcontroller via a 2.5MHz SPI or 400KHz I2C interface, and can operate in a temperature range of -40°C to +105°C.
Intersil battery management system (BMS) scheme diagram
TI solution
TI provides a multi-functional combination of lithium-ion battery monitoring (suitable for 3-16 batteries in series), battery protection, certification and peripheral ICs. The monitor collects important battery parameters, such as voltage, current, and temperature, and forwards this information to the microcontroller. The battery protector detects a variety of fault conditions from simple (only overvoltage) to advanced (detects more faults), such as overvoltage, undervoltage, discharge overcurrent, and short circuit. Authentication and identification ICs provide safety authentication or identification for battery packs and accessories such as charging cables and printer cartridges. Battery peripheral ICs can greatly expand the capacity of battery packs through advanced technologies such as active cell balancing (ACB) technology.
Program features:
TI recommends the active balancing method used in electric vehicles: each battery cell controls the combination of the transformer and the charging circuit through a matrix switch to form a voltage/current "reservoir" function with adjustment function. The inconsistency after charging and discharging leads to a decrease in the charging and discharging capacity of the entire battery. It can be adjusted by the line connected to the reservoir at the back end. During charging, the charging and discharging will not be stopped because the internal voltage of a battery cell is too high. It can also completely release 100% of the energy at the time, thereby extending the driving distance of electric vehicles.
TI's energy conversion efficiency in isolated DC-DC active equalization technology is as high as 87%. For example, the EM1410 chipset is composed of 5 core chips plus 5 power supply chips. The main EMB1432 is a fourteen-channel AFE chip, EMB1428 is a seven-channel gate controller chip, and EMB1499 is a seven-channel voltage control chip. To construct fourteen-channel two-way active battery cell balancing function, connect 14 battery cells in series with a maximum working voltage of 60V, provide 5V two-way balancing voltage and maximum 750V stack output voltage capability, and meet the AECQ-100 automotive electronic verification standard.
Texas Instruments (TI) Battery Management System (BMS) Scheme Diagram
ADI program
ADI's AD7280A has all the functions required for general monitoring of laminated lithium-ion batteries used in electric vehicles. The device has multiplexed battery voltage and auxiliary ADC measurement channels and can be used for battery management of up to 6 batteries. At the same time, an internal reference voltage of ±3 ppm is provided, so that the battery voltage accuracy can reach ±1.6 mV. The ADC resolution is 12 bits, and it takes only 7 μs to convert 48 units.
The AD7280A is powered by a single VDD power supply with a supply voltage range of 8 V to 30 V (absolute maximum rating is 33 V). The device provides six differential analog input channels to handle large common-mode signals across the entire VDD range. The allowable input signal range (VIN (+) to VIN (-)) of each channel is 1 V to 5 V. The input pin can accept six batteries stacked in series. In addition, the device has built-in six auxiliary ADC input channels, which can be used for temperature measurement or system diagnosis.
AD7280A has built-in on-chip registers, which can program the timing of channel measurement according to application requirements. It also has a built-in dynamic reminder function to detect whether the battery voltage or auxiliary ADC input exceeds the user-defined upper or lower limit. AD7280A has a battery balance interface output, which is used to control an external FET transistor and allow each battery to discharge.
The built-in self-test function of the AD7280A can internally apply a known voltage to the ADC input. Using the daisy chain port, up to eight devices can be stacked without separate device isolation.
AD7280A requires only one power supply pin, consumes 6.5 mA under normal operating conditions, and has a conversion rate of 1 MSPS.
ADI battery management system (BMS) scheme diagram
NXP plan
Shiping Group has launched an automotive BMS battery management system solution based on the NXP chip, which can monitor the voltage and temperature of a single battery and monitor the voltage, current, and temperature of the entire string.
Scheme specifications:
Monitor the voltage and temperature of a single battery
Monitor the voltage, current and temperature of the entire string
Passive balance function between single cells
CAN bus or daisy chain connection between battery packs
With multiple protection and diagnostic functions
Single MC33771 can monitor 8- 14 strings of batteries
Built-in passive equalization MOSFET, maximum support 300 mA passive equalization current
Built-in coulomb counter for current detection
ASIL C chip functional safety level
Support up to 15 MC33771 cascading
Detection accuracy 2mV
Support 43 internal self-test functions
Synchronous measurement of voltage and current within 65 us
1. Monitor the battery status in real time. By detecting the external characteristic parameters of the battery (such as voltage, current, temperature, etc.) and using appropriate algorithms, the internal state of the battery (such as capacity and SOC, etc.) can be estimated and monitored. This is the basis and key to the effective operation of the battery management system;
2. Perform thermal management, battery balance management, charge and discharge management, fault alarm, etc. after correctly acquiring the battery status;
3. Establish a communication bus to exchange data with the display system, vehicle controller and charger.
The battery management system (BMS) is mainly divided into two parts. The first part is the front-end analog measurement protection circuit (AFE), including the battery voltage conversion and measurement circuit, the battery balance drive circuit, the switch drive circuit, the current measurement, and the communication circuit; The second part is the back-end data processing module, which is based on the front-end calculations such as voltage, current, and temperature, and returns the necessary information to the system through the communication interface for control.
The current battery management system (BMS) product design solutions are monopolized by foreign manufacturers, and they all use battery management ICs provided by foreign semiconductor IC manufacturers and design with their application solutions as a reference.
Maxim, Linear Technology (acquired by ADI), Intersil, TI, ADI, and NXP are the main solution providers.
Maxim solution
Maxim series products construct a complete 12-cell battery monitoring solution. Maxim's battery monitors (MAX172XX series), battery protectors (DS277X series) and battery selectors (MAX1538) can effectively extend battery life and ensure a safe and reliable system jobs. Its series of high-voltage devices help realize the transition to low-carbon energy solutions. The devices integrate advanced functions to reduce the size, cost and design complexity of the battery management system. Consumers can get higher system reliability, longer battery life and faster time to market.
Features of the Maxim solution:
1. Greatly simplifies the design of multi-cell battery packs. The device contains 12 measurement channels and uses a capacitively isolated stepped SMBus communication bus, which greatly reduces the number of components and reduces costs. This unique architecture allows up to 31 devices to be connected to a series battery pack to monitor up to 372 cells. The capacitance-based interface provides extremely low-cost isolation between battery packs and eliminates cascading electrical failures.
2. With excellent performance, Maxim's high-voltage, small-size BiCMOS process has the industry's highest withstand voltage (80V), excellent ESD protection (±2kV, human body model), and hot-swappable function, ensuring compliance in a wide operating temperature range AEC-Q100 standard maintains high reliability.
3. The analog front end includes a 12-channel voltage measurement data acquisition system and a set of high-voltage, fault-tolerant switch inputs. The high-speed, 12-bit ADC digitizes the battery voltage under test. Two-phase scanning technology is adopted to obtain battery measurement data and correct errors. This technology can measure battery voltage at the same time, and complete the voltage measurement and sampling of all 120 batteries within 10 μs, ensuring excellent accuracy even in noisy systems. The error is less than ±0.25% in the entire battery nominal operating temperature range, and the error is less than ±20mV in the entire AEC-Q100 Class 2 temperature range.
4. The power consumption can be reduced by 10 times (the current is 100μA in working mode) to extend the battery life. The unique built-in shutdown circuit reduces the power consumption to an extremely low level (leakage current is only 1μA), so that the battery can be stored for several years without loss of battery power.
5. For the optimized design of automotive applications, the Maxim solution has internal configuration and self-diagnostic modes, which are essential for the work of the safety monitoring system, and can ensure trouble-free operation in harsh environments with magnetic fields and transient noise. Maxim uses a variety of methods such as high current injection, stripline, and in-vehicle monitoring to conduct comprehensive tests on ICs to ensure reliable operation in battery packs with strong transient electrical signals and magnetic field interference. The device has the pin open circuit and short circuit fault detection functions specified by the FMEA standard, and can handle internal circuit faults.
Maxim scheme diagram
Linear Technology Solution
Linear Technology's series of multi-cell and high-voltage battery pack monitors are complete battery monitoring ICs. They have built-in 12-bit ADCs, accurate voltage references, a high-voltage input multiplexer and a serial interface. These devices can be connected in series (without using optocouplers or opto-isolators) to monitor each cell in a long series connection.
Linear Technology's LTC6804-1 / LTC6804-2-multi-cell battery pack monitors, designed for automotive and transportation applications, specific package AEC-Q100 data.
Program features:
1. It can measure the voltage of up to 12 batteries in series, and the stackable architecture can support hundreds of batteries
2. Built-in isoSPITM interface: 1Mbps isolated serial communication, using a single twisted pair, up to 100 meters, low EMI sensitivity and radiation
3. 1.2mV maximum total measurement error, can complete the measurement of all batteries in the system within 290μs: synchronous voltage and current measurement
4. 16-bit incremental accumulation (ΔΣ) ADC with frequency programmable third-order noise filter
5. System engineering design for ISO26262 standard, passive battery charge balance with programmable timer
6. 5 universal digital I/O or analog inputs: temperature or other sensor inputs, configurable as an I2C or SPI master
7. 4μA sleep mode power supply current
Linear Technology solution application diagram
Intersil solution
Intersi's ISL78600 Li-ion Battery Manager IC supervises up to 12 batteries connected in series. Provides accurate monitoring, battery balancing and extensive system diagnostic functions. Three battery balance modes are combined-manual balance mode, timing balance mode and automatic balance mode. When the automatic balance mode is terminated, it means that the value of the charge transfer specified by the host microcontroller has reached the balance.
Intersil's HEV/EV solution ensures that customers comply with ISO26262 (ASIL) specifications and prevent battery pack failures. The solution also provides built-in fault detection for all major internal functions, and can detect external faults such as line interruptions, overvoltage and undervoltage, as well as temperature and battery balance faults.
The Intersil battery management system provides the high accuracy required for accurate state-of-charge measurement, thereby extending vehicle driving range and high-performance lithium-ion battery life. To do this, each chip uses a 14-bit temperature-compensated data converter that can scan 12 channels in 250 microseconds.
In order to achieve the highest possible reliability of communication within the system, Intersil battery manager uses a high noise immunity and transient fault-tolerant communication mechanism. This fully differential daisy-chain architecture allows multiple battery packs to be stacked together using low-cost twisted pairs, while preventing hot swapping and high transient voltages. The advantages of the Intersil solution can significantly reduce the overall cost of the battery management system.
The ISL78600 allows easy connection to a microcontroller via a 2.5MHz SPI or 400KHz I2C interface, and can operate in a temperature range of -40°C to +105°C.
Intersil battery management system (BMS) scheme diagram
TI solution
TI provides a multi-functional combination of lithium-ion battery monitoring (suitable for 3-16 batteries in series), battery protection, certification and peripheral ICs. The monitor collects important battery parameters, such as voltage, current, and temperature, and forwards this information to the microcontroller. The battery protector detects a variety of fault conditions from simple (only overvoltage) to advanced (detects more faults), such as overvoltage, undervoltage, discharge overcurrent, and short circuit. Authentication and identification ICs provide safety authentication or identification for battery packs and accessories such as charging cables and printer cartridges. Battery peripheral ICs can greatly expand the capacity of battery packs through advanced technologies such as active cell balancing (ACB) technology.
Program features:
TI recommends the active balancing method used in electric vehicles: each battery cell controls the combination of the transformer and the charging circuit through a matrix switch to form a voltage/current "reservoir" function with adjustment function. The inconsistency after charging and discharging leads to a decrease in the charging and discharging capacity of the entire battery. It can be adjusted by the line connected to the reservoir at the back end. During charging, the charging and discharging will not be stopped because the internal voltage of a battery cell is too high. It can also completely release 100% of the energy at the time, thereby extending the driving distance of electric vehicles.
TI's energy conversion efficiency in isolated DC-DC active equalization technology is as high as 87%. For example, the EM1410 chipset is composed of 5 core chips plus 5 power supply chips. The main EMB1432 is a fourteen-channel AFE chip, EMB1428 is a seven-channel gate controller chip, and EMB1499 is a seven-channel voltage control chip. To construct fourteen-channel two-way active battery cell balancing function, connect 14 battery cells in series with a maximum working voltage of 60V, provide 5V two-way balancing voltage and maximum 750V stack output voltage capability, and meet the AECQ-100 automotive electronic verification standard.
Texas Instruments (TI) Battery Management System (BMS) Scheme Diagram
ADI program
ADI's AD7280A has all the functions required for general monitoring of laminated lithium-ion batteries used in electric vehicles. The device has multiplexed battery voltage and auxiliary ADC measurement channels and can be used for battery management of up to 6 batteries. At the same time, an internal reference voltage of ±3 ppm is provided, so that the battery voltage accuracy can reach ±1.6 mV. The ADC resolution is 12 bits, and it takes only 7 μs to convert 48 units.
The AD7280A is powered by a single VDD power supply with a supply voltage range of 8 V to 30 V (absolute maximum rating is 33 V). The device provides six differential analog input channels to handle large common-mode signals across the entire VDD range. The allowable input signal range (VIN (+) to VIN (-)) of each channel is 1 V to 5 V. The input pin can accept six batteries stacked in series. In addition, the device has built-in six auxiliary ADC input channels, which can be used for temperature measurement or system diagnosis.
AD7280A has built-in on-chip registers, which can program the timing of channel measurement according to application requirements. It also has a built-in dynamic reminder function to detect whether the battery voltage or auxiliary ADC input exceeds the user-defined upper or lower limit. AD7280A has a battery balance interface output, which is used to control an external FET transistor and allow each battery to discharge.
The built-in self-test function of the AD7280A can internally apply a known voltage to the ADC input. Using the daisy chain port, up to eight devices can be stacked without separate device isolation.
AD7280A requires only one power supply pin, consumes 6.5 mA under normal operating conditions, and has a conversion rate of 1 MSPS.
ADI battery management system (BMS) scheme diagram
NXP plan
Shiping Group has launched an automotive BMS battery management system solution based on the NXP chip, which can monitor the voltage and temperature of a single battery and monitor the voltage, current, and temperature of the entire string.
Scheme specifications:
Monitor the voltage and temperature of a single battery
Monitor the voltage, current and temperature of the entire string
Passive balance function between single cells
CAN bus or daisy chain connection between battery packs
With multiple protection and diagnostic functions
Single MC33771 can monitor 8- 14 strings of batteries
Built-in passive equalization MOSFET, maximum support 300 mA passive equalization current
Built-in coulomb counter for current detection
ASIL C chip functional safety level
Support up to 15 MC33771 cascading
Detection accuracy 2mV
Support 43 internal self-test functions
Synchronous measurement of voltage and current within 65 us
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