Air heating and cooling system for aircraft batteries

DETAILED DESCRIPTION The present invention is a system for maintaining an aircraft battery at its optimum operating temperature.
By maintaining the temperature of the battery cell electrolyte at or near the optimum design temperature the performance of the battery can be greatly enhanced.
If the cell temperature is too high, the service life of the battery is reduced.
If the cell temperature is too low, the performance (the power delivery capability) of the battery is substantially impaired.
The present invention provides both heating and cooling means for the battery cells.
Heating is accomplished with an air heating system having a means for recirculating heated air around the battery cells.
A low cost external heater is used that is mounted outside the potassium hydroxide environment.
Cooling is accomplished by circulating ambient atmospheric air around the battery cells.
Insulation may be provided around the battery to reduce the heat transfer rate between the battery and the ambient atmospheric air.
The insulation thus provides a very low temperature change rate for the battery when the air system is shut down.
The present invention is particularly suited to aircraft batteries which comprise a plurality of nickel cadmium cells within the battery case.
The cells are provided with ribs on their external surface to define air passageways between the individual cells.
The battery also defines an air feed plenum below the cells and air exhaust plenum above the cells.
An air inlet means is provided for communicating with ambient atmospheric air.
An air exhaust means is provided for routing air from the air exhaust plenum in the battery case to the ambient atmosphere.
Means for generating an air pressure differential between the inlet and exhaust conduits is provided.
When cooling, the air pressure differential is generated by air pressure differentials between the inlet and outlet ports that are open to ambient atmospheric air.
When heating, a recirculating loop is opened between the air access inlet conduit while the access ambient atmospheric air is closed off