Method for symmetrizing an energy storage system

Patent metadata

Field	Value
Publication number	US-10449869-B2
Application number	US-201515531273-A
Country	US
Kind code	B2
Filing date	Nov 19, 2015
Priority date	Nov 28, 2014
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

In a method for balancing an energy storage system, a capacitance of capacitive storage modules of a series circuit of capacitive storage modules is determined. The capacitive storage modules are connected to a balancing device to allow control of a charge of each of the capacitive storage modules via a flow of current between the balancing device and the capacitive storage modules. For each of the capacitive storage modules a module charge is determined from a voltage of the capacitive storage module and a predefined balancing voltage. A reference charge is determined from the module charges of the capacitive storage modules, and a balancing charge is determined for each of the capacitive storage modules from the reference charge and the module charge of the capacitive storage module. The charge of the capacitive storage modules is controlled by exchanging the balancing charge between the capacitive storage module and the balancing device.

First claim

The invention claimed is:

1. A method for balancing an energy storage system, comprising:
determining a capacitance of individual capacitive storage modules of a series circuit of at least two capacitive storage modules, with the at least two capacitive storage modules connected to a balancing device to allow control of a charge of each of the capacitive storage modules via a flow of current between the balancing device and the capacitive storage modules;
determining for each of the individual capacitive storage modules a module charge required to change the individual capacitive storage module from a voltage of the capacitive storage module to a predefined balancing voltage;
determining a reference charge from the module charges of the capacitive storage modules, wherein the reference charge is formed from a maximum value of all the module charges or from an average value of all the module charges;
determining for each of the individual capacitive storage modules a balancing charge from a difference between the reference charge and the module charge of the capacitive storage module; and
controlling the charge of the capacitive storage modules by exchanging the balancing charge between the capacitive storage module and the balancing device.

2. The method of claim 1 , wherein the capacitive storage modules have each capacitor, a double-layer capacitor or a lithium capacitor.

3. The method of claim 1 , wherein the charge is the same for the capacitive storage modules, with a same current flowing through the capacitive storage modules in the series circuit.

4. The method of claim 1 , wherein the balancing voltages of the individual capacitive storage modules are predefined independently of one another.

5. The method of claim 1 , wherein the capacitance of each capacitive storage module is determined by a change in the voltage of the capacitive storage module and in the current through the series circuit of the capacitive storage modules.

6. The method of claim 1 , further comprising connecting the capacitive storage modules to a resistor, and determining the capacitance of each capacitive storage module from the voltage of the capacitive storage module or from the current through the resistor.

7. The method of claim 1 , wherein the balancing charge for the capacitive storage modules is determined from a difference between the reference charge and the module charge of the capacitive storage module.

8. The method of claim 1 , wherein the balancing charge for the capacitive storage modules is determined as a function of a predefined tolerance band of the balancing voltage.

9. The method of claim 1 , wherein the charges of the capacitive storage modules are exchanged between the capacitive storage modules via the balancing device.

10. The method of claim 1 , wherein the balancing voltage of the capacitive storage modules is predefined as a function of a predefined maintenance interval and/or of the capacitance of the capacitive storage modules.

11. The method of claim 1 , wherein the capacitance is determined cyclically.

12. A control device, comprising
an input receiving a voltage of at least two capacitive storage modules of a series circuit of capacitive storage modules, with the at least two capacitive storage modules connected to a balancing device, said control device configured to
generate a control command as a function of the received voltage to allow control of a charge exchange between the capacitive storage modules and the balancing device,
determine for each of the individual capacitive storage modules a module charge required to change the individual capacitive storage module from a voltage of the capacitive storage module to a predefined balancing voltage;
determine a reference charge from the module charges of the capacitive storage modules, wherein the reference charge is formed from a maximum value of all the module charges or from an average value of all the module charges;
determine for each of the individual capacitive storage modules a balancing charge from a difference between the reference charge and the module charge of the capacitive storage module; and
control the charge of the capacitive storage modules by exchanging the balancing charge between the capacitive storage module and the balancing device.

13. An energy storage arrangement, comprising:
an energy storage system including a series circuit of at least two capacitive storage modules, each said capacitive storage module including a capacitor, a double-layer capacitor or a lithium capacitor;
a balancing device connected to each of the capacitive storage modules such as to allow control of a charge of each capacitive storage module via a flow of current between the balancing device and the capacitive storage module; and
a control device comprising an input receiving a voltage of at least two capacitive storage modules of the series circuit of the at least two capacitive storage modules, said control device configured to
generate a control command as a function of the received voltage to allow control of a charge exchange between the capacitive storage modules and the balancing device,
determine for each of the individual capacitive storage modules a module charge required to change the individual capacitive storage module from a voltage of the capacitive storage module to a predefined balancing voltage;
determine a reference charge from the module charges of the capacitive storage modules, wherein the reference charge is formed from a maximum value of all the module charges or from an average value of all the module charges;
determine for each of the individual capacitive storage modules a balancing charge from a difference between the reference charge and the module charge of the capacitive storage module; and
control the charge of the capacitive storage modules by exchanging the balancing charge between the capacitive storage module and the balancing device.

14. The energy storage arrangement of claim 13 , wherein both ends of the series circuit are implemented as terminals of the energy storage system.

15. The energy storage arrangement of claim 13 , wherein the balancing device includes a resistor.

16. The energy storage arrangement of claim 13 , wherein the balancing device includes a current source.

17. The energy storage arrangement of claim 13 , wherein the series circuit of the least two capacitive storage modules includes at least one other storage module.

18. The energy storage arrangement of claim 13 , wherein at least one of the capacitive storage modules includes a series circuit and/or parallel circuit of storage cells.

19. The energy storage arrangement of claim 13 , further comprising at least one constructional unit including at least one capacitive storage module and at least a part of the balancing device.

20. A vehicle, comprising
an energy storage arrangement, said energy storage arrangement comprising an energy storage system including a series circuit of least two capacitive storage modules, each said capacitive storage module including a capacitor, a double-layer capacitor or a lithium capacitor,
a balancing device connected to each of the capacitive storage modules such as to allow control of a charge of each capacitive storage module via a flow of current between the balancing device and the capacitive storage module, and
a control device comprising an input receiving a voltage of at least two capacitive storage modules of the series circuit of the at least two capacitive storage modules, said contro

Assignees

• Siemens Ag

Inventors

• Kleffel Rüdiger
• Quast Fabian
• Ruppert Swen

Classifications

• H02J7/52

  for charge balancing, e.g. equalisation of charge between batteries · CPC title

• H02J7/54

  Passive balancing, e.g. using resistors or parallel MOSFETs · CPC title

• H01G11/14 Primary

  Arrangements or processes for adjusting or protecting hybrid or EDL capacitors (emergency protective circuit arrangements specially adapted for capacitors, and effecting automatic switching in the event of an undesired change from normal working conditions H02H7/16; emergency protective circuit arrangements for limiting excess current or voltages without disconnection H02H9/00) · CPC title

• H02J7/345

  using capacitors as storage or buffering devices · CPC title

• H01M10/4207

  for several batteries or cells simultaneously or sequentially · CPC title