Fuel Cell System Coupled to a Portable Computing Device

Abstract

The disclosed embodiments relate to the design of a fuel cell system which is capable of both providing power to and receiving power from a rechargeable battery in a portable computing device. This eliminates the need for a bulky and heavy battery within the fuel cell system, which can significantly reduce the size, weight and cost of the fuel cell system. This fuel cell system includes a fuel cell stack which converts fuel into electrical power. It also includes a controller which controls operation of the fuel cell system. The fuel cell system additionally includes a power link that transfers electrical power between the fuel cell system and the portable computing device, and a communication link that provides communication between the portable computing device and the controller for the fuel cell system. The controller can regulate both the electrical power provided by the fuel cell system to the portable computing device and the electrical power provided by the rechargeable battery to the fuel cell system.

1 . (canceled) 
     
     
         2 . A fuel cell system for a portable computing device, comprising:
 a fuel cell stack;   an interface to the portable computing device, wherein the interface comprises:
 a power link; and 
 a communication link; and 
   a controller configured to communicate with the portable computing device via the communication link to cause the portable computing device to control current through the power link to regulate the fuel cell stack.   
     
     
         3 . The fuel cell system of  claim 2  wherein the controller causes the portable computing device to control current through the power link to regulate the fuel cell stack by controlling a charging circuit within the portable computing device. 
     
     
         4 . The fuel cell system of  claim 3  wherein the controller controls the charging circuit to supply current from a battery of the portable computing device to the fuel cell system via the power link when the fuel cell stack is not running and during startup of the fuel cell stack. 
     
     
         5 . The fuel cell system of  claim 3  wherein the controller controls the charging circuit to deliver current to a battery of the portable computing device from the fuel cell system via the power link when the fuel cell stack is running. 
     
     
         6 . The fuel cell system of  claim 2  wherein the controller controls portable computing device current in response to changes in hydrogen outlet pressure of the fuel cell stack. 
     
     
         7 . The fuel cell system of  claim 2 , wherein the communication link is bidirectional. 
     
     
         8 . The fuel cell system of  claim 7 , wherein the bidirectional communication link 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.   
     
     
         9 . The fuel cell system of  claim 8 , wherein the computing-device state information includes at least one of:
 a power requirement for the portable computing device; and   a state-of-charge of a rechargeable battery within the portable computing device.   
     
     
         10 . The fuel cell system of  claim 8 , wherein the computing-device control information specifies the portable computing device current to regulate the fuel cell stack. 
     
     
         11 . A portable computing device adapted for use with a fuel cell system, comprising:
 a processor;   a memory; and   an interface to the fuel cell system, wherein the interface comprises,
 a power link; and 
 a communication link; 
   wherein the portable computing device is configured to regulate a fuel cell stack of the fuel cell system by adjusting current through the power link in response to signals received from the fuel cell system via the communication link.   
     
     
         12 . The portable computing device of  claim 11  wherein adjusting current through the power link in response to signals received from the fuel cell system via the communication link comprises charging a battery of the portable computing device to draw power from the fuel cell system. 
     
     
         13 . The portable computing device of  claim 11  wherein adjusting current through the power link in response to signals received from the fuel cell system via the communication link comprises discharging a battery of the portable computing device to deliver power to the fuel cell system. 
     
     
         14 . The portable computing device of  claim 11  wherein the portable computing device is further configured to receive fuel cell state information from the fuel cell system via the communication link and display the fuel cell state information to a user. 
     
     
         15 . The portable computing device of  claim 14 , wherein the fuel cell state information comprises one or more item selected from the group consisting of:
 power available from the fuel cell system; and   fuel remaining in a fuel source for the fuel cell system.   
     
     
         16 . The portable computing device of  claim 11 , wherein the communication link is bidirectional. 
     
     
         17 . The portable computing device of  claim 16 , wherein the bidirectional communication link communicates computing-device state information from the portable computing device to the fuel cell system. 
     
     
         18 . The portable computing device of  claim 17 , 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.   
     
     
         19 . A non-transitory computer-readable medium having stored thereon instructions executable by a portable computing device to cause the portable computing device to:
 receive computing device control information from a fuel cell system via a communication link of an interface with the fuel cell system;   adjust current through a power link of the interface in response to the received computing device control information, thereby regulating a fuel cell stack of the fuel cell system.   
     
     
         20 . The non-transitory computer-readable storage medium of  claim 19  wherein the instructions cause the portable computing device to adjust current through the power link in response to the received computing device control information by charging a battery of the portable computing device to draw power from the fuel cell system. 
     
     
         21 . The non-transitory computer-readable storage medium of  claim 19  wherein the instructions cause the portable computing device to adjust current through the power link in response to the received computing device control information by discharging a battery of the portable computing device to deliver power to the fuel cell system. 
     
     
         22 . The non-transitory computer-readable storage medium of  claim 19  wherein the instructions further cause the portable computing device to receive fuel cell state information from the fuel cell system via the communication link and display the fuel cell state information to a user, wherein the fuel cell state information comprises at least one of power available from the fuel cell system and fuel remaining in a fuel source for the fuel cell system.