Patent Application
20110199026
This disclosure relates to energy storage devices, and more particularly to a system for charging an energy storage device.
Energy harvesters have been used to harvest energy from environmental conditions. However, depending on the type of energy harvester used and the environment into which the energy harvester is placed, an amount of time required for the energy harvester to reach an operational charge may be unpredictable.
A system for charging an energy storage device includes an energy harvester operable to harvest energy from environmental conditions, and to charge an energy storage device at a first rate using the harvested energy. A charging input port detachably receives a secondary energy source. The secondary energy source is operable to charge the energy storage device at a second rate that is faster than the first rate. A sensing module is operable to sense a condition and to transmit a wireless signal indicating an occurrence of the condition.
A method of charging an energy storage device charges an energy storage device at a first rate using an energy harvester, wherein the energy harvester harvests energy from environmental conditions. A secondary energy source is detachably received into a charging input port. The energy storage device is charged at a second rate that is faster than the first rate using the secondary energy source.
These and other features of the present disclosure can be best understood from the following specification and drawings, the following of which is a brief description.
a-e schematically illustrate a plurality of example secondary energy sources operable to be used in connection with the system of
The remote sensing device 13 includes an energy harvester 16 that is operable to harvest energy from environmental conditions, and that is operable to charge the energy storage device 12 at a first rate using the harvested energy. The energy harvester 16 may include one or more photovoltaic cells, for example. A secondary energy source 18 may be detachably received into the device 13 through a charging port 20. The secondary energy source is configured to charge the energy storage device 12 at a second rate that is faster than the first rate.
The remote sensing device 13 is operable to harvest its own energy using energy harvester 16, and therefore may be self-sustaining such that power required to operate the load 14 may be obtained from energy harvested by the energy harvester 16. However, in some conditions it may be desirable to accelerate charging of the energy storage device 12. For example, if the energy storage device 12 is in an uncharged or a discharged state, a technician may wish to configure the remote sensing device 13, or may wish to perform diagnostic testing on the device 13 and may not wish to wait while the energy harvester 16 charges the energy storage device 12, which depending on the size of the energy storage device 12, and depending on the type and location of energy harvester 16 used, could possibly take an unacceptably long time (e.g. several minutes to several hours).
A decision is made as to whether diagnostic testing is desired (step 108). If diagnostic testing is desired, then diagnostic testing may be performed on or using the remote sensing device 13 (step 110), and the secondary energy source 18 may be removed from the charging port 20 (step 111). If the steps 110-111 are performed in this order, the energy harvester 16 can maintain a full charge throughout the diagnostic testing, and one could locate the diagnostic circuitry in a secondary charge circuit (e.g. inside the secondary energy source) to minimize the production cost of the remote sensing device 13. Of course, it is also possible that the secondary energy source 18 may be removed prior to performing diagnostic testing, such that step 111 is performed before step 112.
If no diagnostic testing is desired (step 108), the secondary energy source 18 is removed from charting port 22 (step 112) and the energy harvester 16 may be used to sustain operation of the remote sensing device 13 (step 113).
The energy storage device 12 may include a capacitor, a super capacitor or a rechargeable battery, for example. A super capacitor may have a capacitance on the order of 1-10 farads. Of course, other energy storage devices and other energy storage capacities would be possible. As discussed above, an amount of time that it would take to charge the energy storage device 12 would vary in relation to a capacity of the energy storage device 12 and depending on the type and location of the energy harvester 16, possibly taking minutes or many hours. With such charging times, the benefit of the secondary energy source 18 is apparent, as it would enable a technician to perform step 110 or to allow step 112 to occur much sooner than would otherwise be possible if the technician had to wait for the energy storage device 12 to reach a full charge using only the energy harvester 16.
Referring again to
A diode 28 provides an overvoltage protection for the energy storage device 12 by permitting a flow of current to ground if an amount of voltage from the energy harvester 16 or secondary energy source 18 exceeds a threshold. The diode 28 also determines a voltage at which current flows through LED 22 to provide a “full charge” notification. In one example the diode 28 is a Zener diode. Of course, other types of components or circuits could be used. The remote storage device 13 also includes current limiting resistors 30, 32 that limit current to avoid damage to circuit components, such as the LED 22.
a-e schematically illustrate a plurality of example secondary energy sources 18, each including an extension 40a-e that may be detachably received into the charging port 20.
c schematically illustrates an example hand crank generator power source 18c which is operable to generate a voltage in response to manual rotation of hand crank 44 in a predefined direction (counterclockwise in the example of
A receiver/controller 64 receives wireless signals from transmitter 62, and is operable to control lighting sources 66a-b using power from AC power source 65 in response to receiving the wireless signals. In one example, the receiver/controller 64 turns the lighting sources 66 ON in response to the sensor 60 detecting motion, and turns the lighting sources 66 OFF in response to the sensor 60 not detecting motion for a predetermined period of time, in a “AUTO ON/AUTO OFF” configuration. In one example the receiver/controller 64 may act as the secondary energy source 18 if a connector is plugged into charging port 20 on the remote sensing device 13 and charging port 68 on the receiver/controller 64 such that the receiver/controller 64 acts as an AC power source (see
Although a motion sensor 60 and a wireless signal transmitter have been described as an example load 14, it is understood that other loads would be possible.
Although embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
