# US 8,786,255 B2 · Active charge balancing circuit

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- Number: US 8,786,255 B2
- Document ID: US8786255B2
- Status: Granted
- Kind: B2
- Application number: 12/772,719
- Filed: 2010-05-03
- Published: 2011-11-03
- Granted: 2014-07-22
- Earliest claimed: 2010-05-03
- Assignees: Infineon Technologies AG
- Applicants: Peter Gollob; Uschi Pechlaner
- Inventors: Peter Gollob; Andreas Pechlaner
- Web page: https://patentgrep.com/patent/US8786255B2

## CPC

- H02J 7/52: for charge balancing, e.g. equalisation of charge between batteries
- H01M 10/441: {for several batteries or cells simultaneously or sequentially}
- H01M 10/46: Accumulators structurally combined with charging apparatus (circuits for charging H02J7/00)
- H02J 7/56: Active balancing, e.g. using capacitor-based, inductor-based or DC-DC converters
- G01R 31/396: Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
- H01M 2010/4271: {Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing}
- Y02E 60/10: Energy storage using batteries
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A charge balancing circuit and an energy storage arrangement with a charge balancing circuit are disclosed.

## Claims

### Claim 1

A charge balancing circuit, comprising:
a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each of the cell terminals being configured to be connected to a tap of a charge storage arrangement that comprises a plurality of charge storage cells connected in series;
a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow from the first and second terminals to the cell terminals either in a first direction or in a second direction opposite the first direction depending on a voltage between the first and second terminals; and
a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein, during the first charge balancing mode, the control circuit is configured to cause the switch arrangement to connect the first inductive storage element between terminals of the first charge storage cell during a first step and then connect the first inductive storage element between terminals of the second charge storage cell during a second step.

### Claim 2 (depends on 1)

The charge balancing circuit of claim 1, further comprising:
a second inductive storage element, wherein the first and the second inductive storage elements are inductively coupled with each other; and
a change-over switch configured to selectively connect the first or the second inductive storage element with the first and second terminals of the switch arrangement.

### Claim 3 (depends on 2)

The charge balancing circuit of claim 2, wherein the first and the second inductive storage elements comprise coils having opposite winding senses.

### Claim 4

A charge balancing circuit, comprising:
a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each of the cell terminals being configured to be connected to a tap of a charge storage arrangement that comprises a plurality of charge storage cells connected in series;
a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow from the first and second terminals to the cell terminals either in a first direction or in a second direction opposite the first direction depending on a voltage between the first and second terminals; and
a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, and configured to operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein the switch arrangement comprises
a first group of n+1 switches, with n>1, each switch having a first and a second load terminal, the first load terminal being coupled with one tap,
a second group of n switches, each of the second switches being connected between the second load terminals of two switches of the first group,
a first internal node formed by the second load terminal of one of the switches of the first group, and
a second internal node formed by the second load terminal of another one of the switches of the first group, wherein the first and the second internal nodes are operable to be connected with at least one of the first and second terminals of the switch arrangement.

### Claim 5 (depends on 4)

The charge balancing circuit of claim 4,
wherein the first internal node is connected with the first terminal of the switch arrangement, and
wherein the second internal node is connected with the second terminal of the switch arrangement.

### Claim 6 (depends on 4)

The charge balancing circuit of claim 4, wherein the switches of the first group of switches and the second group of switches comprise bidirectional switches.

### Claim 7 (depends on 4)

The charge balancing circuit of claim 4, wherein the switch arrangement further comprises:
a third group of switches with at least one first switch that is operable to connect the first internal node with the first terminal of the switch arrangement.

### Claim 8 (depends on 7)

The charge balancing circuit of claim 7, wherein the third group of switches further comprises:
a second switch operable to connect the second internal node with the second terminal of the switch arrangement;
a third switch operable to connect the second internal node with the first terminal of the switch arrangement; and
a fourth switch operable to connect the first internal node with the second terminal of the switch arrangement.

### Claim 9 (depends on 7)

The charge balancing circuit of claim 7, wherein the third group of switches further comprises:
a further switch operable to connect the first terminal of the switch arrangement with one of the cell terminals.

### Claim 10 (depends on 1)

The charge balancing circuit of claim 1, wherein the switch arrangement comprises:
a first group of n switches, with n>1, each switch having a first and a second load terminal, each switch having the first load terminal coupled with one tap, and the second load terminal coupled to a first internal node; and
a second group of n switches, with n>1, each switch having a first and a second load terminal, each switch having the first load terminal coupled with one tap, and the second load terminal coupled to a second internal node, wherein the first and the second internal nodes are operable to be coupled with at least one of the first and second terminals of the switch arrangement.

### Claim 11 (depends on 10)

The charge balancing circuit of claim 10,
wherein the first internal node is coupled with the first terminal of the switch arrangement, and
wherein the second internal node is coupled with the second terminal of the switch arrangement.

### Claim 12 (depends on 10)

The charge balancing circuit of claim 10, wherein the switches of the first group of switches and the second group of switches comprise bidirectional switches.

### Claim 13 (depends on 10)

The charge balancing circuit of claim 10, wherein the switch arrangement further comprises a third group of switches with at least one first switch that is operable to connect the first internal node with the first terminal of the switch arrangement.

### Claim 14 (depends on 13)

The charge balancing circuit of claim 13, wherein the third group of switches further comprises:
a second switch operable to connect the second internal node with the second terminal of the switch arrangement;
a third switch operable to connect the second internal node with the first terminal of the switch arrangement; and
a fourth switch operable to connect the first internal node with the second terminal of the switch arrangement.

### Claim 15 (depends on 13)

The charge balancing circuit of claim 13, wherein the third group of switches further comprises a further switch operable to couple the first terminal of the switch arrangement with one of the cell terminals.

### Claim 16

An energy storage arrangement, comprising:
a charge storage arrangement comprising a plurality of charge storage cells connected in series, and a plurality of taps;
a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each cell terminal being connected to a respective one of the taps of the charge storage arrangement;
a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow in both directions from the first and second terminals to the cell terminals; and
a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, and configured to operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein, during the first charge balancing mode, the control circuit is configured to cause the switch arrangement to connect the first inductive storage element between terminals of the first charge storage cell during a first step and then connect the first inductive storage element between terminals of the second charge storage cell during a second step.

### Claim 17 (depends on 16)

The energy storage arrangement of claim 16, further comprising:
a second inductive storage element, wherein the first and the second inductive storage elements are inductively coupled with each other; and
a change-over switch configured to selectively connect the first or the second inductive storage element with the first and second terminals of the switch arrangement.

### Claim 18

An energy storage arrangement, comprising:
a charge storage arrangement comprising a plurality of charge storage cells connected in series, and a plurality of taps;
a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each cell terminal being connected to a respective one of the taps of the charge storage arrangement;
a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow in both directions from the first and second terminals to the cell terminals; and
a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, and configured to operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein the switch arrangement comprises
a first group of n+1 switches, with n>1, each switch having a first and a second load terminal, the first load terminal being coupled with one tap,
a second group of n switches, each of the second switches being connected between the second load terminals of two switches of the first group,
a first internal node formed by the second load terminal of one of the switches of the first group, and
a second internal node formed by the second load terminal of another one of the switches of the first group, wherein the first and the second internal nodes are operable to be connected with at least one of the first and second terminals of the switch arrangement.

### Claim 19 (depends on 16)

The energy storage arrangement of claim 16, wherein the switch arrangement comprises:
a first group of n switches, with n>1, each switch having a first and a second load terminal, each switch having the first load terminal coupled with one tap, and the second load terminal coupled to a first internal node; and
a second group of n switches, with n>1, each switch having a first and a second load terminal, each switch having the first load terminal coupled with one tap, and the second load terminal coupled to a second internal node, wherein the first and the second internal nodes are operable to be coupled with at least one of the first and second terminals of the switch arrangement.

### Claim 20 (depends on 1)

The charge balancing circuit of claim 1, further comprising the charge storage arrangement.

### Claim 21 (depends on 1)

The charge balancing circuit of claim 1, wherein the control circuit is further configured to operate the switch arrangement in a second charge balancing mode providing electrical charge exchange through the first inductive storage element from any first cell of the plurality of charge storage cells to all cells of the plurality of charge storage cells.

### Claim 22 (depends on 1)

The charge balancing circuit of claim 1, wherein the control circuit is further configured to operate the switch arrangement in a third charge balancing mode providing electrical charge exchange through the first inductive storage element from all cells of the plurality of charge storage cells to any first cell of the plurality of charge storage cells.

### Claim 23

A method of operating a charge balancing circuit comprising:
determining at least one control signal for a switch arrangement based on a state of charge of at least one energy storage element of a plurality of energy storage elements;
reconfiguring the switch arrangement according to the at least one control signal; and
configuring the switch arrangement to perform a first charge balancing mode providing electrical charge exchange through a first inductive storage element from any first energy storage element of the plurality of energy storage elements to any second energy storage element of the plurality of energy storage elements, wherein configuring the switch arrangement to perform the first charge balancing mode comprises
causing the switch arrangement to connect the first inductive storage element between terminals of the first energy storage element during a first step, and
causing the switch arrangement to connect the first inductive storage element between terminals of the second energy storage element during a second step after the first step.

### Claim 24 (depends on 23)

The method according to claim 23, further comprising configuring the switch arrangement to perform a second charge balancing mode providing electrical charge exchange through the first inductive storage element from any first energy storage element of the plurality of storage elements to all of the plurality of energy storage elements.

### Claim 25 (depends on 23)

The method according to claim 23, further comprising configuring the switch arrangement to perform a third charge balancing mode providing electrical charge exchange through the first inductive storage element all of the plurality of energy storage elements to any first energy storage element of the plurality of energy storage elements.