Apparatus for simulating high battery temperature for rechargeble battery systems

• US 5,583,415 A
• Filed: 12/27/1994
• Issued: 12/10/1996
• Est. Priority Date: 12/27/1994
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kamke, James F., Meadows, Vernon, Fernandez, Jose M., Garrett, Scott M., Lam, Dao N.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US08/364,583
• Time in Patent Office: 714 Days
• Field of Search: 320/6, 320/15, 320/18, 320/30, 320/35, 320/36, 320/39, 320/40, 429/49
• US Class Current: 320/121
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery system (400) for use with portable electronic products which includes protection circuitry for allowing the battery system to be safely recharged in a recharging system. The battery system (400) includes cells (401) and a plurality of controls including and overcharge protection circuit (433) for limiting the amount of current to the cells (401) by a charging network and a thermistor (415) and thermistor control (417) for controlling the state of the thermistor (415) to simulate a high temperature condition allowing the charging network to switch modes and accommodate battery system (400) which does not following the charging regimen provided by charging system.

Claims

1. A battery system for use with portable electronic products which includes protection circuitry for allowing the battery system to be safely recharged in a charging system comprising:

at least one cell for providing a voltage potential;

overcharge protection means for limiting a current to said at least one cell during a period said at least one cell is being recharged;

a thermistor for measuring a temperature of said at least one cell; and

a thermistor control means for controlling a state of said thermistor to simulate a high temperature condition to said charging system.

2. A battery system as in claim 1 further comprising:

first control means attached to at least one switch for measuring said voltage potential and actuating said at least one switch when said voltage potential increases to a predetermined level.

3. A battery system as in claim 2 further comprising:

second control means attached to said least one switch for measuring said voltage potential of individual cells of said at least one cell and actuating said at least one switch when said voltage potential of one of said at least one cell increases to said predetermined level.

4. A battery system as in claim 3 further comprising:

third control means for measuring said current through said at least one cell and actuating said at least one switch when a predetermined current level is reached to disconnect said at least one switch from said charging system.

5. A battery system as in claim 4 wherein said predetermined current level is indicative of a short circuit of said at least one cell.

6. A battery system as in claim 4 further comprising:

fourth control means for measuring said voltage potential of said at least one cell and actuating said at least one switch when said at least one cell drops to a second predetermined voltage.

7. A battery system as in claim 6 further comprising:

a current detection element for disconnecting said at least one cell from said charging system when said predetermined current level is exceeded.

8. A battery system as in claim 7 wherein said current detection element is a current fuse.

9. A battery system as in claim 7 wherein said current detection element is a resettable fuse.

10. A battery system as in claim 6 further comprising:

a fifth control means for monitoring actuation of said at least one switch and disconnecting an electronic device attached to said battery system to prevent accidental damage thereto.

11. A battery system as in claim 10 wherein said fifth control means is comprised of a transistor switch.

12. A battery system as in claim 11 wherein said fifth control means is comprised of a thermal fuse and at least one zener diode.

13. A battery system as in claim 1 wherein said at least one cell is a lithium ion cell.

14. A lithium ion battery system for use with a portable device comprising:

a plurality of lithium ion cells each having an individual voltage, and providing a cumulative voltage;

a plurality of switches connected to said plurality of lithium ion cells for disconnecting said plurality of lithium ion cells from said portable device;

a current detector for detecting a short circuit and actuating at least one of said plurality of switches;

a primary overvoltage detector for monitoring said cumulative voltage of said plurality of lithium ion cells and actuating at least one switch of said plurality of switches if said cumulative voltage increases above a predetermined level;

a secondary overvoltage detector for monitoring said individual voltages of said plurality of lithium ion cells and actuating at least one switch of said plurality of switches if any of said individual voltages increase above a predetermined level;

a cell undervoltage detector for monitoring the cumulative voltage of said plurality of lithium ion battery cells and actuating at least one switch of said plurality of switches if said cumulative voltage decreases below a predetermined level;

a thermistor for detecting a temperature of said lithium ion cells; and

a thermistor control simulator for controlling a current flowing through said thermistor to allow said thermistor to indicate a false temperature reading.

15. A lithium ion battery system as in claim 14 wherein said temperature reading is a high temperature reading which is monitored by a charging system.

16. A lithium ion battery system as in claim 14 further comprising:

a cell balancing controller for maintaining each cell of said plurality of lithium ion cells at substantially an equal voltage during charging.

18. A lithium ion battery system as in claim 14 further comprising a memory circuit of supplying charging information of said plurality of lithium ion cells to a charging system.

19. A lithium ion battery system as in claim 14 further comprising a delay circuit for delaying actuation of said at least one switch when actuated by said primary cell overvoltage detector.

20. A lithium ion battery system as in claim 19 further comprising a delay circuit for delaying actuation of said at least one switch when actuated by said secondary cell overvoltage detector.

21. A lithium ion battery system as in claim 14 further comprising a portable device operating terminal, charging voltage terminal, charging information terminal and temperature information terminal for conveying information to said portable device and charging system.

22. A lithium ion battery system as in claim 21 further comprising:

a current detector connect serially with said plurality of lithium ion cells for disconnecting said plurality of lithium ion cells from said portable device voltage terminal and said charging voltage terminal.

23. A lithium ion battery system as in claim 22 wherein said current detector is a current fuse.

24. A lithium ion battery system as in claim 22 wherein said current detector is a resettable fuse.

17. A lithium ion battery system as in 14 further comprising:

device overvoltage detector for monitoring actuation of at least one of said plurality of switches and disconnecting said portable device from said plurality of lithium ion cells in response thereto.