Printed battery array outputting selectable voltage and current
A plurality of batteries is printed on a flexible substrate, where each battery may output the same voltage, such as about 1.5 volts. Batteries in a first subset are connectable in parallel by controllable switches to control the maximum current that can be delivered to a load. Batteries in a second subset are also connectable in parallel by additional controllable switches to control the maximum current that can be delivered to the load. Another group of switches can either connect the two subsets of batteries in series, to generate 3 volts, or connect the subsets in parallel to increase the maximum current. Additional subsets of batteries and their associated switches may be further connected to increase the voltage and current. The power supply may be standardized and configured by the user for a particular load, such as a sensor for a medical skin patch.
1. A powered device comprising:
a substrate;
a power supply on the substrate comprising:
a positive output terminal and a negative output terminal;
a plurality of printed batteries on the substrate, the plurality of batteries comprising first batteries in a first subset of batteries and second batteries in a second subset of batteries;
a plurality of switches connected to the plurality of batteries, the switches comprising first switches that selectively connect the first batteries in the first subset of batteries in parallel, second switches that selectively connect the second batteries in the second subset of batteries in parallel, third switches that selectively connect the first subset of batteries in series with the second subset of batteries, and fourth switches that selectively connect the first subset of batteries in parallel with the second subset of batteries; and
a controller on the substrate controlling the first switches, the second switches, the third switches, and the fourth switches.
2. The device of claim 1 wherein the controller automatically controls the plurality of switches.
3. The device of claim 2 wherein the controller automatically controls the plurality of switches based on feedback signals from the batteries.
4. The device of claim 2 further comprising a load coupled to the positive output terminal and the negative output terminal, wherein the controller automatically controls the plurality of switches based on signals from the load.
5. The device of claim 1 wherein the controller is controlled by a user to control the plurality of switches.
6. The device of claim 1 wherein the switches are printed transistors.
7. The device of claim 1 further comprising a voltage detector on the substrate that indicates an output voltage of the power supply.
8. The device of claim 1 further comprising a voltage detector on the substrate that indicates an output voltage of each of the batteries.
9. The device of claim 1 further comprising a voltage detector on the substrate that provides a feedback signal to the controller for controlling the plurality of switches.
10. The device of claim 9 wherein the controller automatically reconfigures the switches to cause the power supply to output a particular voltage.
11. The device of claim 1 wherein the controller is configured to maintain all the switches in an open state until the device is to be used.
12. The device of claim 1 wherein all the switches are normally opened until closed by the controller.
13. The device of claim 1 wherein the controller is configured for electrically isolating a battery via one or more of the switches when the controller determines that the battery has sufficiently lost its charge.
14. The device of claim 1 further comprising a load coupled to the positive output terminal and the negative output terminal, wherein the controller periodically connects some batteries to the load and disconnects other batteries from the load to prolong an effective life of the power supply.
15. The device of claim 1 further comprising a load coupled to the positive output terminal and the negative output terminal, wherein the substrate is flexible and the load is a sensor.
16. The device of claim 15 further comprising a load coupled to the positive output terminal and the negative output terminal, wherein the load is a medical sensor for a patient, the device further comprising an adhesive layer on a surface of the substrate for attaching to the patient's skin for placing the load proximate to the patient's skin.
17. The device of claim 15 further comprising a load supported by the substrate and coupled to the positive output terminal and the negative output terminal.
18. A method of supplying power to a load comprising:
providing a variable power supply on a substrate, the power supply comprising:
a positive output terminal and a negative output terminal;
a plurality of printed batteries on the substrate, the plurality of batteries comprising first batteries in a first subset of batteries and second batteries in a second subset of batteries;
a plurality of switches connected to the plurality of batteries, the switches comprising first switches that selectively connect the first batteries in the first subset of batteries in parallel, second switches that selectively connect the second batteries in the second subset of batteries in parallel, third switches that selectively connect the first subset of batteries in series with the second subset of batteries, and fourth switches that selectively connect the first subset of batteries in parallel with the second subset of batteries; and
a controller on the substrate controlling the first switches, the second switches, the third switches, and the fourth switches;
connecting a load to the positive output terminal and the negative output terminal, the load having electrical input requirements; and
supplying signals by the controller to close selected ones of the plurality of switches to output a voltage across the positive output terminal and the negative output terminal to meet the electrical input requirements of the load.
19. The method of claim 18 wherein the controller automatically detects the electrical requirements of the load and automatically supplies the signals to close the selected ones of the plurality of switches to output the voltage across the positive output terminal and the negative output terminal to meet the electrical input requirements of the load.
20. The method of claim 18 wherein the controller is controlled by a user to supply the signals to close the selected ones of the plurality of switches to output the voltage across the positive output terminal and the negative output terminal to meet the electrical input requirements of the load.