Fuel cell system to power a portable computing device
The disclosed embodiments relate to the design of a portable and cost-effective fuel cell system for a portable computing device. This fuel cell system includes a fuel cell stack which converts fuel into electrical power. It also includes a fuel source for the fuel cell stack and a controller which controls operation of the fuel cell system. The fuel system also includes an interface to the portable computing device, wherein the interface comprises a power link that provides power to the portable computing device, and a bidirectional communication link that provides bidirectional communication between the portable computing device and the controller for the fuel cell system.
1. A fuel cell system for a portable computing device, comprising:
a fuel cell stack which converts fuel to electrical power;
a fuel source for the fuel cell stack;
a controller for the fuel cell system; and
an interface to the portable computing device, wherein the interface comprises:
a power link that provides power to the portable computing device; and
a communication link that provides communication from the portable computing device to the controller for the fuel cell system;
wherein the controller for the fuel cell system is configured to:
receive fuel cell control information from the portable computing device through the communication link; and
use the received fuel cell control information to control the fuel cell system.
2. The fuel cell system of claim 1 , wherein the fuel source is a fuel cartridge detachably affixed to the fuel cell system.
3. The fuel cell system of claim 1 , further comprising a fan within the fuel cell system configured to produce an air flow that:
supplies oxygen to the fuel cell system; and
provides cooling for the fuel cell system.
4. The fuel cell system of claim 1 , further comprising an internal rechargeable battery within the fuel cell system configured to level a load for the fuel cell system.
5. The fuel cell system of claim 4 , further comprising a first direct-current DC-to-DC converter, which converts a voltage from the fuel cell stack into a battery voltage for the internal rechargeable battery.
6. The fuel cell system of claim 5 , further comprising a second DC-to-DC converter, which converts the battery voltage to a computing-device voltage which is used to power the computing device.
7. The fuel cell system of claim 1 wherein the controller for the fuel cell system is further configured to send fuel cell state information from the fuel cell system to the portable computing device through the communication link.
8. The fuel cell system of claim 1 , wherein the fuel cell control information specifies one or more of the following:
a request for a specified amount of power from the fuel cell system;
a fuel cell stack current to be pulled off the fuel cell stack.
9. The fuel cell system of claim 1 , wherein the fuel cell state information and the fuel cell control information are used in one or more feedback-control loops to actively control one or more operating parameters of the fuel cell system.
10. The fuel cell system of claim 1 , wherein the bidirectional communication link also communicates:
computing-device state information from the portable computing device to the fuel cell system; and
computing-device control information from the fuel cell system to the portable computing device.
11. The fuel cell system of claim 10 , wherein the computing-device state information specifies one or more of the following:
a power requirement for the portable computing device; and
a state-of-charge of a rechargeable battery within the portable computing device.
12. The fuel cell system of claim 10 , wherein the computing-device control information specifies:
a power state for the portable computing device, wherein the portable computing device uses the power state to control power usage of components within the portable computing device.
13. The fuel cell system of claim 1 , wherein the power link comprises a wireless link.
14. The fuel cell system of claim 1 , wherein the communication link comprises a wireless link.
15. The fuel cell system of claim 7 , wherein the fuel cell state information specifies one or more of the following:
how much power is available from the fuel cell system;
a state-of-charge of an internal rechargeable battery within the fuel cell system.
16. The fuel cell system of claim 7 wherein the fuel cell state information specifies one or more of a temperature of the fuel cell stack, a pressure at an inlet of the fuel cell stack, and a pressure at an outlet of the fuel cell stack.
17. The fuel cell system of claim 7 wherein the fuel cell state information specifies a cell voltage for one or more cells in the fuel cell stack.
18. The fuel cell system of claim 7 wherein the fuel cell state information specifies an amount of fuel remaining in the fuel source.
19. The fuel cell system of claim 8 wherein the fuel cell control information specifies a fan speed within the fuel cell system.
20. The fuel cell system of claim 8 wherein the fuel cell control information includes a command to run diagnostics for the fuel cell system.