Battery charge balancing system having parallel switched energy storage elements

Claim 3

A method as recited in claim 1, wherein alternately repeating steps (a) and (b) further comprises alternately repeating steps (a) and (b) at a predetermined rate.

Claim 4

A method as recited in claim 1, further comprising measuring variables representing relatives state of charge of said batteries; wherein alternately repeating steps (a) and (b) further comprises alternately repeating steps (a) and (b) at a rate which is a function of charge imbalance among said batteries.

Claim 5

A method as recited in claim 1, wherein alternately repeating steps (a) and (b) further comprises alternately repeating steps (a) and (b) when said batteries are being discharged to a device external to said plurality of series-connected batteries and said plurality of energy storage circuits.

Claim 6

A method as recited in claim 1, wherein alternately repeating steps (a) and (b) further comprises alternately repeating steps (a) and (b) when said batteries are being discharged to provide power to an electric motor.

Claim 7

A method as recited in claim 1, wherein alternately repeating steps (a) and (b) further comprises alternately repeating steps (a) and (b) when said batteries are being charged from a device external to said plurality of series-connected batteries and said plurality of energy storage circuits.

Claim 8

A method as recited in claim 1, wherein alternately repeating steps (a) and (b) further comprises alternately repeating steps (a) and (b) when said batteries are neither being charged nor discharged.

Claim 11

A system as recited in claim 8, further comprising means for measuring voltages across each of said batteries; wherein said alternate connection means further comprises means for performing said alternate connections at a rate which is a function of said measured voltages.

Claim 12

A system as recited in claim 8, wherein said alternate connection means further comprises means for performing said alternate connections at a predetermined rate.

Claim 13

A system as recited in claim 8, wherein said alternate connection means further comprises means for performing said alternate connections when said batteries are being charged from a charger external to said system.

Claim 14

A method as recited in claim 8, wherein said alternate connection means further comprises means for performing said alternate connections when said batteries are being discharged to a device external to said plurality of series-connected batteries and said plurality of energy storage circuits.

Claim 15

A system as recited in claim 8, further comprising an electric motor, and wherein said alternate connection means further comprises means for performing said alternate connections when said batteries are being discharged to provide power to said motor.

Claim 16

A system as recited in claim 8, wherein said alternate connection means further comprises means for performing said alternate connections when said batteries are being neither charged nor discharged.

Claim 17

A battery charge balancing system comprising: a plurality of series-connected batteries each having a first and second terminal; a plurality of switching circuits equal in number to said plurality of batteries, each said switching circuit coupled to a respective one of said batteries and further comprising: an energy storage circuit having a first and second termination; a first switch coupled between said first termination of said energy storage circuit and the first terminal of said respective battery; a second switch coupled between said second termination of said energy storage circuit and the second terminal of said respective battery; a third switch coupled between said first termination of said energy storage circuit and a first common point; a fourth switch coupled between said second termination of said energy storage circuit and a second common point; wherein said first common points of said switching circuits are coupled together and said second common points of said switching circuits are coupled together.

Claim 18

A battery charge balancing system comprising: a plurality of series-connected batteries each having a first and second terminal; a plurality of switching circuits equal in number to said plurality of batteries, each said switching circuit coupled to a respective one of said batteries and further comprising: an energy storage circuit having a first and second termination; a first switch coupled between said first termination of said energy storage circuit and the first terminal of said respective battery; a second switch coupled between said second termination of said energy storage circuit and the second terminal of said respective battery; a third switch coupled between said first termination of said energy storage circuit and a first common point; a fourth switch coupled between said second termination of said energy storage circuit and a second common point; wherein said first common points of said switching circuits are coupled together and said second common points of said switching circuits are coupled together.

Claim 19

A battery charge balancing system as recited in claim 15, further comprising means for controlling said switching circuits to alternately connect said energy storage circuits across their respective batteries and in parallel with each other.

Claim 20

A battery charge balancing system as recited in claim 15, further comprising means for controlling said switching circuits to alternately connect a plurality of said energy storage circuits across a first said battery and then across a second said battery, to transfer charge from said first battery to said second battery.