Converting battery module with resistor programmation of default output voltage

• US 5,821,734 A
• Filed: 08/29/1997
• Issued: 10/13/1998
• Est. Priority Date: 08/29/1997
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Faulk, Richard A.
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/921,232
• Time in Patent Office: 410 Days
• Field of Search: 320/116, 320/118, 320/121, 320/123, 320/124, 320/132, 320/140, 320/158, 320/163, 320/108, 320/138, 320/148
• US Class Current: 320/124
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A universal battery pack which includes an integral power converter and a dynamically adjustable output voltage. The default output voltage is set by an optional resistor connection, which shifts the voltage-dividing ratio into the error amplifier. In a multiple-battery configuration, the output voltages of the separate battery modules are preferably set to slightly different values. Thus the battery module with the highest output voltage setting will be completely exhausted first. This results in automatic battery switchover, without requiring any control algorithm or logic for execution of the switchover.

Claims

1. A battery pack subsystem, comprising, in a single sealed module:

one or more electrochemical cells, collectively having first and second current-carrying connections; and

first and second external power terminals which are operatively connected to said first and second connections through a voltage converter, which is operated by a control circuit to adjust the voltage ratio between said connections and said terminals;

wherein said voltage ratio is set, under at least some conditions, by an external resistor which is connected to a third external terminal of said subsystem.

2. The battery pack subsystem of claim 1, wherein said electrochemical cells are lithium-ion cells.

3. The battery pack subsystem of claim 1, wherein said external resistor is also connected to said first external power terminal.

4. The battery pack subsystem of claim 1, wherein said external resistor is also connected to the more negative of said first and second external power terminals.

5. The battery pack subsystem of claim 1, wherein said external resistor is connected into a voltage divider which scales a feedback voltage into an error amplifier.

6. The battery pack subsystem of claim 1, wherein said control circuit also can communicate through a digital communications interface, and can be commanded through said interface to further change said voltage ratio without any change in said external resistor.

7. A computer system, comprising:

a user input device;

a microprocessor operatively connected to detect inputs from said input device;

memory which is connected to be read/write accessible by said microprocessor; and

a detachable battery pack subsystem, connected to other parts of said computer system through first and second external power terminals and through a third external terminal, and which comprises, in a single sealed module;

one or more electrochemical cells, collectively having first and second current-carrying connections;

said first and second power terminals being operatively connected to said first and second connections through a voltage converter, which is operated by a control circuit to adjust the voltage ratio between said connections and said terminals;

wherein said voltage ratio is set, under at least some conditions, by an external resistor, outside said subsystem, which is connected to said third terminal of said subsystem.

8. The battery pack subsystem of claim 7, wherein said electrochemical cells are lithium-ion cells.

9. The battery pack subsystem of claim 7, wherein said external resistor is also connected to said first external power terminal.

10. The battery pack subsystem of claim 7, wherein said external resistor is also connected to the more negative of said first and second external power terminals.

11. The battery pack subsystem of claim 7, wherein said external resistor is connected into a voltage divider which scales a feedback voltage into an error amplifier.

12. The battery pack subsystem of claim 7, wherein said control circuit also can communicate through a digital communications interface, and can be commanded through said interface to further change said voltage ratio without any change in said external resistor.

13. A method for operating a battery pack subsystem contained in a single sealed module, comprising the steps of:

a) operating a switch-mode power converter, to controllably vary the voltage ratio between current-carrying connections of one or more electrochemical cells and first and second external power terminals;

setting said voltage ratio, under at least some conditions, by an external resistor which is connected to a third external terminal of said subsystem.

14. The method of claim 13, wherein said electrochemical cells are lithium-ion cells.

15. A method for providing power to an electronic system from multiple battery modules, comprising the steps of:

a.) providing power to said system from a first battery module which has a programmable output voltage and which is programmed to provide a first output voltage, while not providing power to said system from a second battery module which has a programmable output voltage and which is programmed to provide a second output voltage which is smaller in magnitude than said first output voltage;

said first and second modules being electrically connected in parallel;

b.) providing power to said system from a second module, which is programmed to a second output voltage which is lower than said first output voltage, after said first battery module can longer provide power above said second voltage;

whereby during discharge said first module will be substantially exhausted before said second module is drawn on.

16. The method of claim 15, wherein said first and second modules are programmed by first and second external resistors respectively.

17. The method of claim 15, wherein said first and second modules are identical, and are programmed to said first and second voltages by first and second external resistors which have different values.

18. An electronic system, comprising:

one or more power-consuming components;

multiple detachable battery modules connected to respective battery connections of said system;

a first one of said battery modules including a power converter which provides a first programmably adjustable output voltage;

a second one of said battery modules including a power converter which provides a second programmably adjustable output voltage which is smaller than said first output voltage;

said first and second modules being electrically connected in parallel;

whereby during discharge said first module will be substantially exhausted before said second module is drawn on.