TI Smart Battery Technology Protects & Manages Multi-Cell Lithium Battery Systems
Texas Instruments Inc. (TI) introduced three new smart battery management integrated circuits that are said to improve measurement and protection of multi-cell, lithium-based battery packs. The controllers are said to simplify design in multi-cell lithium-based rechargeable batteries used in uninterruptible power supplies and applications, such as cordless power tools, power-assisted bicycles, and portable medical and test equipment.
TI claims that its bq78PL114 battery management controller provides complete lithium battery system control, monitoring and safety functions for 4-series cells. The device integrates accurate battery fuel gauge technology with what is described as extremely efficient cell balancing, short-circuit detection and battery protection. The bq78PL114 is completely user-configurable with parametric tables set in Flash memory to support a variety of Li-Ion and Li-Polymer chemistries, operating conditions, safety control and data reporting design requirements. It is claimed that the device can be configured easily using TI’s bqWizard™ fully programmable graphical user interface and requires no algorithm or firmware development.
In addition to the controller, TI introduced its bq76PL102 dual-cell battery monitor, which performs simultaneous voltage and temperature monitoring of each cell and reports those parameters over TI’s proprietary PowerLAN™ communications interface. By leveraging the PowerLAN interface, a designer can combine multiple bq76PL102 monitor devices with the bq78PL114 controller to create a smart battery solution for up to 12 rechargeable cells. Real-time communications is possible in all operating conditions, even during widely fluctuating load conditions. The scalable PowerLAN architecture is also said to provide robust communications in tough electromagnetic and radio frequency interference situations, while avoiding excess power draw and a large number of discrete components.
Partitioning of the battery monitoring function cell-by-cell enables a more accurate state of charge measurement. With this in mind, the bq78PL114- based system is said to help extend battery life and system runtime with TI’s patented PowerPump cell balancing technology. This technology uses a charge-transfer methodology that does not waste excess energy as heat, but moves energy dynamically from cell to cell with very high efficiency. Precise balancing occurs at every stage of operation – at charge, discharge and rest. With PowerPump technology, cell balancing is automatically coordinated between all cells in the system.
The bq78PL114 comes in a 48-pin, 7 x 7 mm QFN package, with a suggested resale price of $5.65 in 100-piece quantities. The bq77PL900 comes in a 48-pin SSOP package, and has a suggested resale price of $3.70 in 100- piece quantities. The bq76PL102 is currently sampling with expected availability later in the fourth quarter. It comes in a 16-pin, 3 x 3 mm QFN package, with a suggested resale price of $1.90 in 100-unit quantities.
