First Published in U.S. Tech The Global Electronics Publication 9/13/2014
By Robin Mitchell Hee, Jason Walsh, and Matthew Barsotti, Trust Automation, Inc., San Luis Obispo, CA
Battery power is essential for a wide range of portable and mobile electronic devices, and advances in battery technology can serve many different applications. To assist a variety of different applications, Trust Automation has introduced a new modular approach to battery power in the Agile Energy Management System™ (AEMS™) equipped with the firm’s proprietary Energy Management Network Technology™. While many battery designs are limited to single package styles or custom enclosures, AEMS employs a design based on modules that can be assembled to meet different applications while still maintaining standardized protection and monitoring requirements. Much thought has been invested in the design and development of these power systems, from the selection and screening of individual cells to the final development and qualification of complete systems. The end result is a “green” solution that meets the needs of customers in defense, medical, industrial, and semiconductor industries.
The AEMS design achieves reliability and predictability through its advanced battery management system (BMS). Internal proprietary hardware and firmware allows real-time measurement of battery status, including state-of-health, state-of-charge or discharge, charge current, individual cell voltages, temperatures, and serialization and recertification data. Onboard flash memory allows the recording of pertinent data critical to the health of a battery. Real-time data is available to an end user through a customizable external telemetry interface that supports multiple common communications formats (such as Ethernet, RS-422, and CAN buses). The capability to receive real-time, state-of-health data is a key enabler that provides users with increased mission assurance and reliability for a battery, from shelf storage until integration into an application and delivery of expected mission performance.
Safety is a key feature designed into AEMS — not just to protect downstream systems in critical applications, but to provide a layer of protection for battery cells from inadvertent or deliberate mishandling, improper connection or abuse during assembly, integration, or operation. Features embedded in every AEMS product include protection from short-circuit, over-current, over-charge, under-voltage, and over-temperature conditions. Onboard switches automatically disconnect chargers/load inputs in response to these conditions to preserve the health of the battery. Real-time fault status is reported as a part of the telemetry interface; an optional “Battle Short” mode provides the capability to bypass these protection features for mission-critical “flight to failure” type applications. Proper protection features are critical to ensure the safety and reliability of any energy-management system.
AEMS technology is flexible and configurable with the capability to seamlessly integrate any cell chemistry (0-5V) from any cell manufacturer, with particular emphasis on the latest developments in lithium-ion chemistry, lithium-ion-titanate (LiTiO) cells, lithium-ion-cobalt (LiCoO) cells, and lithium-ion-iron (LiFePO) cells. An AEMS solution consists of the model 8701 battery management system and multiple model 8702 telemetry modules. The model 8702 telemetry modules are the fundamental building blocks of the AEMS technology, with each module capable of supporting as many as 12 cells in series. The 8702 modules feature a unique self-enumerating scheme that simplifies plug-and-play replacement of modules and allows modules to be swapped in and out of a system as needed. Modules are connected in series to form a stack to provide the necessary system voltage to 700V. The flexibility of the modules and the Energy Management Network Technology provide a distributed battery solution that can be readily adapted to a user’s specific requirements. Modules have additional input/output (I/O) and onboard capabilities to support the integration of additional customer-specific sensor measurements, such as sensors for pressure, humidity, and shock.
The 8701 battery management system provides the overall control, protection, monitoring, and external telemetry interface functionality to support a stack of modules within an AEMS solution. It manages communications with individual modules and serves as the primary control for charge/discharge protection.
Traceability is a key to the successful development of any battery system, with particular emphasis placed on cell source selection. AEMS cells originate from a traceable manufacturing supply source with reliable high-quality standards. Cells are purchased through direct agreements with manufacturers, avoiding random distribution and counterfeit issues. Trust Automation can provide cell testing per customer requirements for validation, to ensure extreme reliability prior to release. Built to AS9100 and ISO9001:2008 standards and lot numbers, every AEMS solution is traceable at both cell and system levels; every system is shipped with certificates of conformance.