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Manual Number 9019286 • Revision E, January 06, 2022
SECTION 4 OPERATION
4.1 DESCRIPTION
The True Blue Power TB20 Advanced Lithium-ion Battery is designed to supply power for starting
an aircraft engine and providing emergency backup power to aircraft systems in the event of
primary power generation loss. It utilizes rechargeable Nanophosphate lithium-ion cells in a
parallel and series configuration to provide the specified voltage, power and total energy capacity.
The unit supplies power through a connector with positive and negative power terminals and
provides battery status and communication through an 18-pin circular connector.
4.2 CONSTRUCTION AND THEORY OF OPERATION
Cells
The TB20 Advanced Lithium-ion Battery contains 64 individual cylindrical lithium-ion cells.
Lithium-ion battery cells have a very high energy density, producing more power than
comparable battery types in a significantly lighter package. The cell’s high-performance
Nanophosphate chemistry is a proprietary form of lithium iron phosphate (LiFePO4). The
lithium iron phosphate chemistry provides safety enhancements over alternative lithium
technologies by producing a cell that is more abuse tolerant to external conditions like over-
charge or short circuit. It has a very low self-discharge rate, high cycle life, and is more stable
with significantly less-energetic failure modes. The Nanophosphate advantage enhances
typical lithium iron phosphate chemistries by providing exceptional power and energy. The
combination of these characteristics make it an excellent choice for use in aircraft
applications where high power, less weight, and enhanced safety are of utmost importance.
Battery Modules
The TB20 is comprised of two identical battery modules. In each module, four individual cells
are connected in parallel to form a battery string; and eight strings are connected in series to
produce a module of 32 total cells. At a full, rested charge, each cell (and string of cells)
supplies approximately 3.3 VDC. The individual cells provide up to 120A of current and 2.5Ah
of energy, or capacity. When connected as described above, each module is rated to provide
10Ah of energy at 26.4VDC. When two modules are connected in parallel, the battery
provides a voltage of 26.4VDC, a total capacity of 20Ah, and a peak current of 960A. Each
module contains two circuit boards, the Control and Switch boards. Monitoring wires are used
to report cell voltages to the Control board for balancing, protections, status and health.
Additionally, each module has multiple temperature sensors, bus bars with individual cell
fuses, cell heaters and mechanical construction designed to secure the cells for an aircraft
environment. The individual cell fuses allow for the potential of a single cell failure to occur
without a significant safety concern or complete loss of function.
Summary of Contents for True Blue Power TB20 Series
Page 1: ...Revision E January 6 2022...
