Methods and apparatus for autonomous balancing and communication in a battery system

1. An apparatus for a battery pack having a plurality of series-connected batteries, comprising:

a communication bus comprising a plurality of series-connected capacitors;

a plurality of management cells, wherein each management cell is: connected to the communication bus via a node, and directly connected to a respective battery from the battery pack and configured to perform autonomous balancing of the respective battery, wherein each management cell includes at least one switch element configured to selectively connect a terminal of the respective battery to the communication bus; and

a first controller connected to the communication bus, wherein the first controller utilizes the communication bus to communicate with each management cell.

2. The apparatus according to claim 1 , wherein each capacitor is connected between two directly-adjacent management cells from the plurality of management cells.

3. The apparatus according to claim 1 , wherein each management cell is configured to:

detect an error in the respective battery from the battery pack, wherein the error is related to at least one of:

a temperature of the respective battery;

a current of the respective battery; and

a voltage of the respective battery; and

generate an error signal according to the detected error.

4. The apparatus according to claim 1 , wherein each management cell, from the plurality of management cells, comprises:

a second controller configured to:

generate a first control signal;

generate a second control signal; and

communicate with the first controller.

5. The apparatus of according to claim 4 , wherein the first and second controller communicate using at least one of: a Local Interconnect Network protocol, a Single Edge Position Modulation technique, a Controller Area Network protocol, and 1-Wire protocol.

6. The apparatus according to claim 4 , wherein each management cell, from the plurality of management cells, comprises a transceiver connected between the node and the second controller.

7. The apparatus according to claim 6 , wherein each management cell further comprises:

the at least one switch element including a first switch element configured to selectively connect a first terminal of the respective battery to the communication bus; and

the at least one switch element including a second switch element configured to selectively connect a second terminal of the respective battery to the communication bus.

8. The apparatus according to claim 7 , wherein:

the first switch element is responsive to the first control signal;

the second switch element is responsive to the second control signal; and

the first and second control signals are non-overlapping signals.

9. The apparatus according to claim 7 , wherein:

the first switch element comprises a P-channel transistor;

the second switch element comprises an N-channel transistor.

10. A method for autonomous balancing and communication in a battery system having a plurality of series-connected batteries connected to a communication bus, comprising:

performing autonomous balancing comprising:

transferring charge from a first battery, from the plurality of batteries, to a second battery, from the plurality of batteries, comprising:

generating a first control signal with a local control system associated with the first battery;

selectively operating a first switch according to the first control signal;

generating a second control signal with the local control system;

selectively operating a second switch according to the second control signal;

selectively connecting a first terminal of the first battery to a capacitive storage device with the first switch; and

selectively connecting a second terminal of the first battery to the capacitive storage device with the second switch;

detecting an error condition in at least one battery from the plurality of batteries; and

activating communication between the local control system and a main controller in response to the error condition, wherein the communication comprises:

generating, with the main controller, a communication signal;

transmitting the communication signal across the communication bus to the local control system; and

generating a reply signal with the local control system according to the error condition; and

transmitting the reply signal to the main controller via the communication bus,

wherein the communication bus comprises a plurality of series-connected capacitors including the capacitive storage device.

11. The method according to claim 10 , wherein activating the communication comprises utilizing at least one of: a Local Interconnect Network protocol, a Single Edge Position Modulation technique, a Controller Area Network protocol, and 1-Wire protocol.

12. The method according to claim 10 , wherein generating the first and second control signals comprises counting with a timer for a predetermined period of time.

13. The method according to claim 10 , wherein the error condition relates to at least one of: a temperature, a current, and a voltage.

14. The method according to claim 13 , wherein generating the first control signal comprises comparing a node voltage of the local control system to a threshold voltage; and generating the second control signal comprises comparing the node voltage to the threshold voltage.

15. A system, comprising:

a battery pack comprising a plurality of series-connected batteries; and

an autonomous balancing and communication circuit connected to the battery pack and comprising: a first controller, a communication bus comprising a plurality of series-connected capacitors, and a management network; wherein:

the management network and the communication bus operate together to perform autonomous voltage balancing for each battery from the battery pack;

the first controller and the management network utilize the communication bus to communicate with each other and monitor each battery from the battery pack for an error condition; wherein the error relates to at least one of: a temperature, and a current;

wherein the management network comprises a plurality of management cells connected together via the communication bus, wherein each management cell is connected to: the communication bus via a node, and a positive terminal and a negative terminal of a respective battery from the battery pack; and

wherein each management cell from the plurality of management cells comprises: a first switch element connected to the node and configured to selectively connect the positive terminal to the communication bus, and a second switch element connected to the node and configured to selectively connect the negative terminal to the communication bus.

16. The system according to claim 15 , wherein the first controller is connected to the communication bus and configured to communicate with each battery from the battery pack via at least one of: a Local Interconnect Network protocol and a Single Edge Position Modulation technique.

17. The system according to claim 15 , wherein each management cell from the plurality of management cells comprises a second controller configured to:

selectively operate the first switch element according to a first control signal;

selectively operate the second switch element according to a second control signal;

communicate with the first controller.

18. The system according to claim 17 , wherein each management cell further comprises a comparator connected to the node and configured to:

compare a voltage at the node to a threshold voltage;

generate a comparator signal based on the comparison; and

transmit the comparator signal to the second controller.