BMS controller with better lithium battery performance, longer battery life, and high accuracy

     STMicroelectronics L9961 Battery Management System (BMS) chip provides market-leading accuracy and flexibility, improves performance and safety of Li-ion and Li-polymer batteries, and extends battery life. It comes in a 5mm x 5mm x 1mm 32-pin VFQFPN package.

     Suitable for battery packs up to 25V, the L9961 is capable of monitoring, balancing and protecting batteries in a variety of applications requiring high energy density lithium batteries. Cordless power tools, backup energy storage systems, uninterruptible power supplies, portable and semi-portable devices, and medical devices can all benefit from the advanced features of the L9961.

     The L9961 has many built-in features, including dual predrivers with configurable high and low sides to control the battery pack's safety relay; Embedded non-volatile memory stores configuration data, and the microcontroller does not need to rewrite data to the controller each time the system is started. The I2C interface handles system configuration and communication with the host controller, transmitting battery charge status (SOC) and health status (SOH) data.

     Thanks to a high resolution analog-to-digital converter (ADC) and a current detection amplifier, the L9961 has a cell voltage detection accuracy of ±15mV and a battery current detection accuracy of less than 0.25%. Accurate measurement enables high accuracy passive battery voltage balancing and coulomb counting, and supports safety functions such as overvoltage and undervoltage detection, balanced undervoltage protection, overcurrent detection, and short-circuit discharge protection. When connected to an external thermistor, the L9961 can monitor the battery pack temperature, including overheat/underheat monitoring, and manage the battery pack fuse. L9961 has strong resistance to degeneration and supports hot swap.

     While extending battery life and improving safety, the L9961 is also very energy efficient, drawing very little power from its battery pack. The product has two power-saving modes: deep sleep and standby. In deep sleep mode, current consumption is reduced to 2μA. In standby mode, the on-chip voltage regulator is in operation, facilitating quick recovery of the chip and reducing current consumption to 5μA.