ADI HEV/EV Li-Ion Battery
Management Solution
Application Description
The automotive industry is transitioning from nickel-metal hydride battery solutions to lithium-ion (Li-ion) due to Li-ion’s superior energy and power capabilities
in hybrid and pure electric vehicles.
Typically micro/mild hybrid vehicles require batteries that can deliver between 60 V to 200 V. NiMH still has some advantages at these lower voltage and energy
requirements. However, battery packs of >300 V are typically required in full hybrid/plug-in hybrid or pure electric vehicles, in which Li-ion is the favored solution.
Despite the different pack sizes, Li-ion power-trains have similar needs in terms of monitoring, extracting performance in a harsh environment, providing reliable
and safe energy management, and reducing overall system costs.
System Requirement and Design Challenge
Reliably getting the most energy, power, and lifetime from a Li-ion battery requires sophisticated battery monitoring electronics. Such electronics monitor cell
voltage and cell temperature, monitor stack voltage and stack current across series-connected cells, balance cell voltage between cells, and transmit data
signals across voltage barriers. The goal is to ensure the battery operates efficiently and safely during drive and charge cycles and to prolong lifetime.
A battery management system (BMS) must perform precision measurements across different cells, in a domain with high common voltage and up to 200 A
switching transients. The system requires mV levels of accuracy, and sampling must be synchronized within tight latency windows. Sampling speed and accuracy
contribute to overall system efficiency.
Reliability is a key requirement. Systems need to provide fail-safes to detect faults in cells, cables, monitors, and communication buses, among others. Redundancy
is often used with primary monitors working with backup monitors. Data protection mechanisms also help detect errors.
Low power consumption is a requirement to minimize drainage of cells and contribution of BMS solution to cell imbalance. The consumption of primary monitoring
IC, backup monitoring IC, and isolation circuits should be as low as possible.
Solutions from Analog Devices
Analog Devices’(ADI) leadership position in signal processing and high performance analog technologies and reputation for reliability and quality, combined
with relationships with leading automotive suppliers, result in the capabilities and system knowledge to provide solutions optimized to meet these challenging
BMS needs.
ADI’s primary monitoring IC, AD7280A, can be used to monitor six channels of voltage and temperature with 1.6 mV typical accuracy. Multiple AD7280A’s can
be daisy-chained to monitor up to 48 cells in one circuit board. The IC provides best-in-class conversion speed and data protection. The 1 μs per channel
conversion time means practically simultaneous multiple channel conversions; full read-back of data over 48-cells is achieved in less than 2 ms. Write and read
communication between the IC and processor is protected by CRC. The IC also provides control for passive cell balancing. Current consumption is less than 6 mA
typical in conversion mode and 1.8 μA typical in power-down mode.
ADI provides backup monitoring via the AD8280, which can report cell faults individually in the event of errors in other circuitry in the monitoring system loop.
The combination of the AD7280A and AD8280 can enhance the ability of a system to realize system level safety targets.
For stack current measuring, the ADuC703x, with integrated PGA, ADCs, and processor core, provide a cost-effective option allowing users to achieve ultrahigh
dynamic range and accuracy in current measurement.
ADI’s iCoupler® digital isolators enable lowest power consumption at data rates optimized for automotive. The tiny footprint and variety of integration options
enable system solutions with lowest component count and board space, while also providing the highest levels of reliability and quality over lifetime. They are
widely adopted as SPI/GPIO/clock isolation between high voltage circuit and low voltage circuit domains. ADI’s unique integrated power and digital isolator
isoPower® solution provides 500 mW of isolated power and multichannel digital isolation, offering cost and area savings relative to discrete dc-to-dc and isolator
solutions. ADI offers a wide array of integration possibilities and the product roadmap is constantly evolving.
automotive.analog.com
Main Signal Chain: Li-Ion BMS ≤150 V
PACK+
LOGIC
PRIMARY
MONITOR IC
6V+6T
PRIMARY
MONITOR IC
BACKUP
MONITOR IC
SPI
BACKUP
MONITOR IC
14V
CAN PHY
CAN BUS
isoPOWER
6V+6T
ALERTS
UC
DIGITAL
ISOLATOR
PRIMARY
MONITOR IC
BACKUP
MONITOR IC
DIGITAL
ISOLATOR
REGULATOR
6V+6T
CONTROL I/O
CONVERTER
PROCESSOR
SHUNT
DIGITAL
ISOLATOR
HALL CURRENT SENSOR
ADI PART =
PACK−
Main Signal Chain: Li-Ion BMS ≥300 V
PACK+
PRIMARY
MONITOR IC
BACKUP
MONITOR IC
ALERTS
SPI
6V+6T
PRIMARY
MONITOR IC
BACKUP
MONITOR IC
DIGITAL
ISOLATOR
14V
isoPOWER
DIGITAL
ISOLATOR
CONTROL I/O
SUPERVISOR
UC
MASTER BMU
CAN PHY
BATTERY UNIT 1
6V+6T
REGULATOR
SLAVE BMU FOR BATTERY UNIT 1: UP TO 48 CHANNELS
REGULATOR
CAN PHY
UC
BACKUP
MONITOR IC
ALERTS
SPI
6V+6T
PRIMARY
MONITOR IC
BACKUP
MONITOR IC
DIGITAL
ISOLATOR
SUPERVISOR
isoPOWER
UC
CONTROL I/O
DIGITAL
ISOLATOR
CAN BUS
PRIMARY
MONITOR IC
CAN PHY
BATTERY UNIT N
6V+6T
REGULATOR
SLAVE BMU FOR BATTERY UNIT N: UP TO 48 CHANNELS
DIGITAL
ISOLATOR
CONVERTER
PROCESSOR
HALL CURRENT SENSOR
PACK−
ADI PART =
Note: The signal chain above is representative of a typical HEV/EV Li-ion Battery Management Solution. The technical requirements of the blocks vary, but the products listed in the
table are representative ADI's solutions that meet some of those requirement.
2 | ADI HEV/EV Li-Ion Battery Management Solution
Main Products
Part Number
Description
Temperature
Primary Monitor IC
6 voltage and 6 aux channels, 0.5 V to 27.5 V common-mode voltage, high input
AD7280A
impedance, 1 μs per channel conversion time, 1.6 mV typ accuracy, cell balancing
interface, daisy chain interface, CRC protection
Backup Monitor IC
6 voltage and 2 temperature channels, adjustable threshold OV, UV, OT, separate or
AD8280W
shared alert, daisy chain interface, self test, 6 V to 30 V supply, Design News’ 2011
Golden Mousetrap Award Winner
Benefits
−40°C to 105°C
High accuracy, fast conversion, daisy
chain interface, data protection, low
power consumption
−40°C to 105°C
Standalone monitor, daisy chain interface,
self test
iCoupler Digital Isolator
ADuM1200/
ADuM1201W
2-channel, 1 M/10 M/25 Mbps data rate, 2.5 kV rms isolation, 3.0 V to 5.5 V supply,
1.2 mA operation current per channel @ 0 Mbps to 2 Mbps
−40°C to 125°C
High data rate, low current consumption,
GPIO or clock isolation
ADuM1300/
ADuM1301W
3-channel, 1 M/10 Mbps data rate, 2.5 kV rms isolation, 3.0 V to 5.5 V supply, 1.2 mA
operation current per channel @ 0 Mbps to 2 Mbps
−40°C to 125°C
High data rate, low current consumption,
GPIO or clock isolation
ADuM1400/
ADuM1401/
ADuM1402W
4-channel, 1 M/10 Mbps data rate, 2.5 kV rms isolation, 3.0 V to 5.5 V supply, 1.0 mA
operation current per channel @ 0 Mbps to 2 Mbps
−40°C to 125°C
High data rate, low current consumption,
GPIO/SPI/clock isolation
ADuM1250W
2-channel, 1 Mbps data rate, 2.5 kV rms isolation, 3.0 V to 5.5 V supply, optimized for
bidirectional I2C, 2.8 mA operation current per channel
−40°C to 125°C
High data rate, low current consumption,
GPIO/I2C isolator
−40°C to 105°C
Integrated digital and power isolator
isoPower Power Isolator
ADuM5401/
ADuM5402/
ADuM5403W
4-channel digital isolator, 25 Mbps data rate, integrated 5 V, 500 mW dc-to-dc, 2.5 kV
rms isolation
Converter Processor
ADuC7036W
16-bit current and voltage/temperature ADCs, 1 to 512 × gain PGA and −200 mV to
+300 mV input range for current channel, 1 Hz to 8 kHz throughout, ARM7TDMI core,
96 kB flash, SPI, LIN/BSD
−40°C to 115°C
Integrated solution, ultra high dynamic
range and accuracy
ADuC7039W
16-bit current and voltage/temperature ADCs, 1 to 512 × gain PGA and −200 mV to
+300 mV input range for current channel, 10 Hz to 1 kHz throughout, ARM7TDMI core,
64 kB flash, SPI, LIN
−40°C to 115°C
Integrated solution, ultra high dynamic
range and accuracy, low cost
*-W suffix represents automotive grade
Design Resources
Evaluation Boards
• EVAL-AD7280AEDZ, EVAL-CED1Z
• AD8280-EVALZ
• Li-Ion BMS Demo
• EVAL-ADuMQSEBZ
Circuits from the Lab™
• Lithium on Battery Stack Monitor with Both Signal and Power Isolation
(CN0197)—www.analog.com/CN0197
• 500 V Common-Mode Voltage Current Monitor (CN0218)—
www.analog.com/CN0218
• Low Cost Level Shifted Low Side Current Monitor for Negative High
Voltage Rails (CN0188)—www.analog.com/CN0188
• A Novel Analog-to-Analog Isolator Using an Isolated Sigma-Delta
Modulator, Isolated DC-to-DC Converter, and Active Filter (CN0185)—
www.analog.com/CN0185
automotive.analog.com| 3
Design Tools for ADuC703x Converter and Processor
• IAR IDE Embedded Workbench or Keil IDE uVision MDK-ARM
• Segger J-Link/J-Trace debugger
• ADI LIN Downloader: LIN Dongle, ADI LIN Windows Serial Downloader: LINBWSD
• ADI QuickStart Evaluation Kit
• Example code and application notes at ADI FTP—ftp://ftp.analog.com/pub/MicroConverter/ADuC703x/
• EngineerZone analog microcontrollers—ez.analog.com/community/analog-microcontrollers
TM
For more automotive application and product information, please visit
automotive.analog.com
Customer Interaction Center
Toll-free number 1-800-225-5234 (Singapore)
Sample request, please contact ADI regional office or visit
www.analog.com/sample
1-800-419-0108 (India)
Email cic.asia@analog.com
EngineerZone ez.analog.com
Free Sample www.analog.com/sample
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BR10431-0-12/11
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