Automotive battery cell monitoring & balancing

Optimize system performance through cell balancing and monitor key battery parameters

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Overview

The cell monitoring and balancing (CMB) device, also known as the BMS IC or Analog Front End (AFE), measures cell voltages and temperatures for state of charge (SoC), ensuring safe operation within the safe operating area (SOA). It performs low-power diagnostics and housekeeping and communicates with the main controller for cell balancing and pack thermal management triggering disconnection and alerts when needed.

Benefits

  • Exceptional robustness
  • Lowest system cost
  • Highly scalable
  • TLE9012DQU: Cell monitoring ICs
  • TLE9012DQU: ASSP and programmable
  • TLE9015DQU: Wired iso UART
  • CYW89820: Wireless isolation

Block diagram

About

Extending an electric vehicle's driving range and lifetime

Battery packs are constructed by connecting numerous single cells in series, which inevitably result in production variances, for example, different cell characteristics, capacities, or heterogeneous thermal spreads in the pack.

Over time, the small differences between cells in multicell battery stacks are magnified during each charge and discharge cycle. Weaker cells with lower capacity reaching maximum voltage sooner than others force the charging process of the entire pack to stop; in this case, the full capacity of the battery cannot be used.

As a result, using the automotive cell monitoring and balancing (CMB) device to compensate the weaker cells by equalizing the charge across the entire stack is essential in extending an electric vehicle's driving range and lifetime.

Additionally, to achieve extremely low-power dedicated housekeeping functions, such as periodically scheduled cell measurements and state analysis required for functional safety, the CMB can operate independently of the BMS's master controller. Safety features such as signaling over- or under-voltage, thermal stress, and emergency alarms are triggered autonomously.

Safe and robust isolation

The CMB topologies are characterized by cell counts and isolation requirements. More stacked battery cell monitoring and balancing devices are required as the number of series cells in a battery pack increase. Isolation is critical, especially in high-voltage battery management systems, where the battery pack must be isolated at all times and the master controller is connected to the 12 V domain.

Isolated wired BMS topology: Infineon provides iso UART transceiver solutions with exceptional robustness for both capacitive and inductive isolation. The iso UART supports complicated cell topologies by enabling high-speed communication across many daisy-chained monitoring devices. For additional robustness, redundant ring daisy-chaining ensures continuous communication even if a link breaks. CRC-protected data frames complement communication robustness.

Isolated wireless BMS topology: Alternatively, to meet the even higher requirement of isolating CMBs, a wireless transceiver is a perfect solution. Infineon offers a set of automotive-grade Bluetooth® devices that support BLE-connected mesh, offering superior network availability and communication bandwidth.

Wireless BMS - CYW89820
High-voltage BMS
Enhance your battery balancing design with lowest PPM rates

Infineon's highly integrated products significantly decrease the footprint and help customers reduce costs by minimizing PCB size. Besides, Infineon's zero-defect Mindset is reflected in the lowest PPM rates in the market and significantly reduces vehicle downtime and returns.

Extending an electric vehicle's driving range and lifetime

Battery packs are constructed by connecting numerous single cells in series, which inevitably result in production variances, for example, different cell characteristics, capacities, or heterogeneous thermal spreads in the pack.

Over time, the small differences between cells in multicell battery stacks are magnified during each charge and discharge cycle. Weaker cells with lower capacity reaching maximum voltage sooner than others force the charging process of the entire pack to stop; in this case, the full capacity of the battery cannot be used.

As a result, using the automotive cell monitoring and balancing (CMB) device to compensate the weaker cells by equalizing the charge across the entire stack is essential in extending an electric vehicle's driving range and lifetime.

Additionally, to achieve extremely low-power dedicated housekeeping functions, such as periodically scheduled cell measurements and state analysis required for functional safety, the CMB can operate independently of the BMS's master controller. Safety features such as signaling over- or under-voltage, thermal stress, and emergency alarms are triggered autonomously.

Safe and robust isolation

The CMB topologies are characterized by cell counts and isolation requirements. More stacked battery cell monitoring and balancing devices are required as the number of series cells in a battery pack increase. Isolation is critical, especially in high-voltage battery management systems, where the battery pack must be isolated at all times and the master controller is connected to the 12 V domain.

Isolated wired BMS topology: Infineon provides iso UART transceiver solutions with exceptional robustness for both capacitive and inductive isolation. The iso UART supports complicated cell topologies by enabling high-speed communication across many daisy-chained monitoring devices. For additional robustness, redundant ring daisy-chaining ensures continuous communication even if a link breaks. CRC-protected data frames complement communication robustness.

Isolated wireless BMS topology: Alternatively, to meet the even higher requirement of isolating CMBs, a wireless transceiver is a perfect solution. Infineon offers a set of automotive-grade Bluetooth® devices that support BLE-connected mesh, offering superior network availability and communication bandwidth.

Wireless BMS - CYW89820
High-voltage BMS

Enhance your battery balancing design with lowest PPM rates

Infineon's highly integrated products significantly decrease the footprint and help customers reduce costs by minimizing PCB size. Besides, Infineon's zero-defect Mindset is reflected in the lowest PPM rates in the market and significantly reduces vehicle downtime and returns.

Design resources

Partner solutions

Developer community

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