Battery management system for control of lithium power cells

• US 9,887,560 B2
• Filed: 08/03/2015
• Issued: 02/06/2018
• 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
• Primary Examiner(s): Siek, Vuthe
• Application Number:
  US14/817,051
• Publication Number:
  US 20170133867A1
• Time in Patent Office: 918 Days
• 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 battery pack connector for connecting the battery pack to a charger or a device to be powered by the battery pack;

a main bus connecting the positive terminal of the rechargeable cell with a positive connector of the 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;

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

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; and

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.

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

3. The battery pack of claim 2, further comprising a boost circuit in electrical communication with the n-FET, the boost circuit configured to provide a pre-determined bias voltage to a gate of the n-FET to drive the n-FET to conduct a charging current to the first and second rechargeable cells.

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 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 rechargeable cells.

6. 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.

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

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

8. The battery pack of claim 7, wherein the indicator is an LED light.

9. An intelligent battery pack, comprising:

a connector 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;

an n-FET 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 n-FET 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 n-FET to open the n-FET 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;

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; and

a boost circuit in electrical communication with the n-FET, the boost circuit configured to provide a pre-determined bias voltage to a gate of the n-FET to drive the n-FET to conduct a charging current to the first and second rechargeable cells.

10. The intelligent battery pack of claim 9, wherein the primary protection circuit includes a primary protection processor configured to monitor the charging and discharging of the cells.

11. The intelligent battery pack of claim 9, wherein the primary protection circuit includes a primary protection processor configured to control the charging and discharging of the cells.

12. The intelligent battery pack of claim 9, 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.

13. The intelligent battery pack of claim 9, 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 n-FET to close the n-FET to provide a voltage across the positive and negative terminals of the connector.

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

a rechargeable cell having a positive and a negative terminal;

a battery pack connector for connecting the battery pack to a charger or a device to be powered by the battery pack;

a main bus connecting the positive terminal of the rechargeable cell with a positive connector of the 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,

an n-FET disposed in the front-side bus between the positive terminal of the cell and the positive connector of the battery pack, the n-FET 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;

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 n-FET to close the n-FET to provide a voltage across the positive and negative terminals of the connector.

15. The battery pack of claim 14, further comprising a boost circuit in electrical communication with the n-FET, the boost circuit configured to provide a pre-determined bias voltage to a gate of the n-FET to drive the n-FET to conduct a charging current to the first and second rechargeable cells.