New Industry Products

Battery Cell Controller Platform & Reference Design for Next-Generation EVs

November 15, 2018 by Paul Shepard

NXP Semiconductors N.V. has announced a new battery cell controller portfolio and reference design suitable for a wide range of automotive battery management systems.  Designed to deliver industry leading measurement accuracy and flexible embedded functional safety mechanisms, the portfolio's benefits also enhance NXP's platform approach to power control.

The new battery cell controllers combined with NXP's comprehensive portfolio of automotive MCUs, power management system basis chips (SBCs), and communication transceivers provide readily useable reference design platforms for controlling high-capacity energy storage in electric vehicles.

The platforms are designed to help carmakers deliver the next generation of hybrid and electric vehicles with greater speed and less development risk.

NXP's new battery cell controller ICs pair with NXP's full portfolio of functional safety system basis chips and MCUs to enable scalable battery management solutions based on their industry leading precision, robust communication and advanced functional safety up to ASIL-D.

Reference Design

NewTec NTBMS is an e-mobility reference design and complete safety support package for Battery Management Systems. It is constructed with a two-board approach a functional safety System-on-Module (Safety SoM) board and a Battery Management System (BMS) application board.

The Safety SoM is based on NXP's S32K144 and KEA microcontrollers, and FS4503C safety power system. The BMS application board is based on NXP's MC33772B battery cell controller IC.

Typical use cases would be:

  • Automotive Battery Management System for 14V auxiliary battery
  • Monitoring of starter batteries
  • Extendable to 48V battery systems
  • Stationary Energy Storage systems; Smart Grid

In addition, the Safety SoM can be used as a generic safety computer board addressing a wide area of applications such as motor control, Valve Control systems, safety PLC or Motorcycle ABS.

The support package includes the necessary safety documentation and software for certification purposes. It is intended for device manufacturers with Lithium-ion batteries and suppliers of automotive or industrial applications with a high degree of reliability and safety in accordance with ISO 26262 targeting safety level up to ASIL C, or IEC61508 SIL2.

 

Features include:

  • Permanent measurement of cell voltages
  • Over-temperature protection
  • Overcurrent / overvoltage detection
  • Undervoltage detection (short circuit)
  • Safe relay (breaker) control (ASIL C)
  • Unintended relay close
  • Unintended relay open
  • Various definable Safe States
  • LIN and CAN bus interface
  • Crash detection
  • Overcurrent control fuse
  • Power supply with watchdog protection
  • Control of up to 6 Lithium-ion battery cells
  • Electrical current carrying capability: 200 A continuous current, 800A maximum current
  • Operating Current <25 mA@RT
  • Intrusive diagnostics (performed by MCU)
  • Memory storage (RAM & flash)
  • Power management (low power and normal mode)
  • All components AEC-Q qualified
  • Programmable in C

Battery Cell Controller ICs

The new battery cell controllers (MC33771B and MC33772B) advance the state-of-the-art in measurement capability and functional integration.

  • Converts cell measurements of a 96-cell high voltage battery within <546us, and communicate data to the pack controller within 4.1ms with typical accuracies of +/-0.8mV after soldering over voltage, temperature, and lifetime.
  • Enables highly accurate cell impedance calculations for state-of-health monitoring using unique synchronized current sensing.
  • Integrates 0.8-Ohm MOSFETs with dedicated timers for each cell for effective and simultaneous charge-balancing of each cell
  • Provides embedded functional safety mechanisms and diagnostics to effectively support highest functional safety goals.

"Volkswagen is working hard to address the increasingly demanding performance and functional safety requirements in the next generation of battery management systems," said Dr. Michal Bruna - Manager PEP Electronics and Testing by Volkswagen Kompetenz Center Elektromobilität. "We undertook an extended evaluation process to approve NXP's MC33771B battery cell controller for our future system. We trust NXP's leadership & innovation to enable us to realize these important goals towards a green and safe society."

More than a dozen automotive Tier-1 customers have adopted NXP's battery management solutions globally for use in production and are currently in development with multiple carmakers. The implementations span multiple applications including economical battery management of 14V batteries, highly integrated 48V systems for mild-hybrid vehicles and high voltage battery stacks and junction boxes with up to 96 cells for 200V to 800V hybrid and pure electric vehicles.