14-Cell Li-ion Battery Management IC Maximizes Battery Cell Life and Driving Range for Hybrid and Electric Vehicles

Published  August 8, 2019   0
14-Cell Li-ion Battery Management IC Maximizes Battery Cell Life and Driving Range for Hybrid and Electric Vehicles

Renesas Electronics Corporation released its fourth-generation lithium-ion (Li-ion) battery management IC ISL78714 offers unmatched lifetime accuracy. The ISL78714 delivers accurate cell voltage and temperature monitoring. Also, the new IC comes with cell balancing and extensive system diagnostics to protect 14-cell Li-ion battery packs while maximizing range and driving time for hybrid and electric vehicles (HEV/MHEV/PHEV/BEV). The ISL78714 meets the stringent reliability and efficiency specifications of battery pack technologies for all EV versions including HEV / PHEV, with safety characteristics that enable automotive companies to attain an automotive safety integrity level of ISO 26262 (ASIL D).


The IC ISL78714 comes with loaded features that monitors and balances up to 14 series connected cells with ±2mV accuracy across automotive temperature ranges allowing system developers make informed decisions based on absolute voltage levels. The IC ISL78714 comes with up to six external temperature inputs (two available from GPIOs), fault detection and diagnostics for all key internal functions. Also, the IC offers associated data acquisition circuitry and a precision 14-bit analog-to-digital converter. The IC ISL78714 also monitors and reads back over/under voltage, open wire conditions, temperature, and fault status for 112 cells in less than 10ms, or 70 cells in 6.5ms.


A proprietary daisy chain can be used to connect multiple ISL78714’s which supports systems up to 420 cells (30 ICs) that provide industry-leading EMC/EMI and transient immunity, exceeding automotive requirements. The daisy-chain architecture of IC ISL78714 utilises low-cost capacitive or transformer isolation, or a combination of both, with twisted pair wiring to stack multiple battery packs together while protecting against hot plug and high voltage transients. The IC ISL78714 features a watchdog timer that automatically shuts down a daisy-chained IC if communications is lost with the master MCU.


Key Features of ISL78714 Battery Management IC:

  • Monitors and manages up to 14 cell voltages with ±2mV measurement accuracy
  • Robust two-wire daisy chain communications system using capacitor or transformer coupling up to 1 Mbps
  • Fully differential cell input range of ±5V accommodates fuel cell and bus bar measurement requirements for aging battery packs
  • 15-year board level accuracy (long term drift) of ±6mV @ ±6σ
  • High diagnostic coverage for cell voltage and temperature measurements
  • AEC-Q100 Grade-2 qualified and specified for operation from -40°C to +105°C


The Renesas also provides a battery management system (BMS) reference design that integrates five ISL78714 ICs and a RH850/P1M MCU to form a complete 70-cell evaluation platform for external balancing. The reference design kit includes setup and data logging via CAN and UAR. The kit also includes GUI, Altium layout files and low-level drivers for the RH850 peripherals and ISL78714. Hardware, software, and interface reference manuals are provided along with an EMC report. So, the complete package of reference design kit helps electric vehicle system designers to scale to any battery pack size, port their software to the RH850 MCU, and save up to one year of development time.


The ISL78714 Li-ion battery management IC can be ordered in samples as well as in production quantities which is available now in a 64-lead TQFP package along with the evaluation board, and BMS reference design kit.