BATTERY MANAGEMENT SYSTEM FOR CONTROL OF LITHIUM POWER CELLS

• US 20120274279A1
• Filed: 04/27/2012
• Published: 11/01/2012
• Est. Priority Date: 04/28/2011
• Status: Active Grant

• Current Assignee: Zoll Circulation Incorporated (Asahi Kasei Corporation)
• Original Assignee: Zoll Circulation Incorporated (Asahi Kasei Corporation)
• Inventors: Banos, Orlando, Deam, David, Smith, Richard
• Granted Patent: US 9,099,877 B2
• Time in Patent Office: Days
• US Class Current: 320/112
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0036 using connection detecting circuits H02J7/0034 takes precedence
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

An intelligent rechargeable battery pack having a battery management system for monitoring and controlling the charging and discharging of the battery pack is described. The battery management system includes primary and secondary protection circuits for monitoring the charging and discharging of the battery. Individual battery cells forming the battery pack are connected by a main bus to a connector for connection to a battery charger or a device to be powered, and the main bus may be interrupted by a switch controlled by the battery management system to prevent damage to the battery during charging or discharging of the battery.

Claims

1. A battery pack for powering a device, comprising:

a rechargeable cell having a positive and a negative terminal;

a main bus connecting the positive terminal of the rechargeable cell with a positive connector of a battery pack connector and also connecting the negative terminal of the rechargeable cell with a negative connector of the battery pack connector; and

a battery management system in electrical communication with the rechargeable cell, including;

a processor for monitoring an input related to the state of charge of the cell,

a switch disposed in the front-side bus between the positive terminal of the cell and the positive connector of the battery pack, the switch responsive to a signal generated by the processor in response to the input related to the state of charge of the cell to control the charging or discharging of the cell.

2. The battery pack of claim 1, wherein the switch is a n-FET device.

3. The battery pack of claim 1, further comprising:

a second rechargeable cell connected in series with the first rechargeable cell; and

a monitoring circuit, in electrical communication with the processor, the monitoring circuit monitoring the voltage of the first and second rechargeable cells and providing a signal for each rechargeable cell to the processor, the signal representative of a level of voltage measured across a negative and positive terminal of each cell, the monitoring circuit including a first switch connecting the first rechargeable cell to a first bleeder circuit, the first switch responsive to an overvoltage signal from the processor to close the first switch to prevent overcharging of the first rechargeable cell, the monitoring circuit also including a second switch connecting the second rechargeable cell to a second bleeder circuit, the second switch responsive to an overvoltage signal from the processor to close the second switch to prevent overcharging of the second rechargeable cell.

4. The battery pack of claim 1, further comprising:

a temperature monitoring circuit for monitoring the temperature of the battery pack and for providing a signal related to the temperature of the battery pack to the processor; and

wherein the processor receives and analyses the temperature signal to determine if the temperature of the battery pack is within a pre-selected range of temperature, and if the temperature of the battery pack is not within the pre-selected range of temperatures, the processor provides a signal to the switch to disconnect the positive terminal of the cell from the positive connector of the battery pack.

5. The battery pack of claim 1, further comprising:

a state of charge monitoring circuit for providing an indication of the amount of charge available from the battery pack for powering a device.

6. The battery pack of claim 1, further comprising:

a battery pack isolation circuit in electrical communication with the processor, the battery isolation circuit configured to provide a connection signal to the processor indicating that the connector of the battery pack are connected to a battery charger or device to be powered; and

wherein the processor responds to the connection signal by sending a signal to the switch to close the switch to provide a voltage across the positive and negative terminals of the connector.

7. The battery pack of claim 6, wherein the battery pack isolation circuit includes a mechanical switch that has a closed condition when the battery connector of the battery pack is connected to a battery charger or device to be powered;

and

wherein the processor responds to the closed condition of the mechanical switch to provide a voltage across the positive and negative terminals of the connector.

8. The battery pack of claim 1, further comprising:

a communication bus connecting the processor to the connector and to other components of the battery management system, the communication bus configured to provide communication between the processor and the other components of the battery management system, and to other systems, processors, networks or storage media external to the battery pack.

9. The battery pack of claim 1, further comprising:

indicator means mounted on an exterior of the battery pack, the indicator means providing a visual indication of information related to the operation of the battery.

10. The battery pack of claim 9, wherein the indicator means is at least one light emitting diode.

18. A device to be powered by the battery pack of claim 1.

19. The device of claim 18, wherein the device is a medical device.

22. The device of claim 19, wherein the device is a mechanical compression device.

24. The battery pack of claim 1, wherein the battery pack is configured to power a mechanical compression device for at least thirty minutes.

25. The battery pack of claim 1, wherein the battery pack is configured to power a mechanical compression device for at least 20 minutes when the mechanical compression device is used to treat a larger than average size patient.

11. An intelligent battery pack, comprising:

a housing;

a connector mounted on an end of the housing and configured to engage a connector disposed in or on a device to be powered;

a plurality of rechargeable battery cells, each of the cells having a positive and a negative terminal, and each of the cells connected in series by a main bus having a positive side connected to a positive terminal of the connector and a negative side connected to a negative terminal of the connector, the plurality of cells disposed within the housing;

a switch disposed in the positive side of the main bus between the positive terminal of the connector and the plurality of cells;

a processor for controlling the operation of the battery pack;

a primary protection circuit in electrical communication with the processor, the primary protection circuit including;

a plurality of monitoring circuits in electrical communication, each one of the plurality of monitoring circuits for monitoring a parameter related to the state of charge of an individual one of the plurality of cells, and

a plurality of bleed circuits, each of the plurality of bleed circuits connected to an individual one of the cells to bleed the cells in response to the parameter for the cell monitored by the monitoring circuit connected to that cell to prevent an overcharge of the cell;

a secondary protection circuit for protection of battery pack from short circuits;

a battery management system in electrical communication with the connector, the switch and the plurality of monitoring circuits, the battery management system configured to monitor the charging and discharging of the cells and to provide a signal to the switch to open the switch if a fault is detected;

a state of charge monitoring circuit, including a sensor for determining an amount of current flowing through the main bus, a state of charge processor in electrical communication with the sensor, a state of charge memory in electrical communication with the state of charge processor, the memory for storing information related to the battery cells and also to the amount of current flowing through the main bus, wherein the state of charge processor, based on the information stored in the state of charge memory and input from the sensor determines the amount of current available from the battery; and

a communication bus in electrical communication with the connector, the processor, the primary protection circuit, the secondary protection circuit, the battery management system and the state of charge monitoring system for providing for communications between the connector, the processor, the primary protection circuit, the secondary protection circuit, the battery management system and the state of charge monitoring system.

12. The intelligent battery pack of claim 11, wherein the switch is an n-channel field effect transistor.

13. The intelligent battery pack of claim 11, wherein the primary protection circuit includes a primary protection processor configured to monitor the charging and discharging of the cells.

14. The intelligent battery pack of claim 11, wherein the primary protection circuit includes a primary protection processor configured to control the charging and discharging of the cells.

15. The intelligent battery pack of claim 11, wherein the processor is also configured to communicate information through the communication bus to the state of charge processor, the information used by the state of charge processor to determine the amount of current available from the battery cells and to store the determined amount of current available in the state of charge memory.

16. The intelligent battery pack of claim 11, further comprising:

a temperature monitoring circuit to determine the temperature of the battery back, the temperature monitoring circuit communicating the temperature of the battery pack to the primary protection circuit; and

wherein the primary protection circuit is configured to send a signal to the switch to open the switch if the temperature of the battery pack is not within a pre-selected range of temperature values.

17. The intelligent battery pack of claim 11, further comprising:

a battery pack isolation circuit in electrical communication with the processor, the battery isolation circuit configured to provide a connection signal to the processor indicating that the connector of the battery pack is connected to a battery charger or device to be powered; and

wherein the processor responds to the connection signal by sending a signal to the switch to close the switch to provide a voltage across the positive and negative terminals of the connector.

20. A device powered by the intelligent battery pack of claim 11.

21. The device of claim 20, wherein the device is a medical device.

23. The device of claim 21, wherein the device is a mechanical compression device.

26. The battery pack of claim 11, wherein the battery pack is configured to power a mechanical compression device for at least thirty minutes.

27. The battery pack of claim 11, wherein the battery pack is configured to power a mechanical compression device for at least 20 minutes when the mechanical compression device is used to treat a larger than average size patient.