Electric energy storage units connected in series and selectively charged/discharged via a balancing circuit or directly from a charger or to a load

• US 9,318,779 B2
• Filed: 03/02/2012
• Issued: 04/19/2016
• Est. Priority Date: 09/02/2009
• Status: Active Grant

• Current Assignee: Japan Aerospace Exploration Agency, Japan Capacitor Industrial Co., Ltd.
• Original Assignee: Japan Aerospace Exploration Agency, Japan Capacitor Industrial Co., Ltd.
• Inventors: Uno, Masatoshi, Kukita, Akio, Ito, Kazushige, Sekido, Tsutomu
• Primary Examiner(s): Rodas, Richard Isla
• Assistant Examiner(s): Henze-Gongola, David V
• Application Number:
  US13/411,480
• Publication Number:
  US 20120194138A1
• Time in Patent Office: 1,509 Days
• Field of Search: 320/121, 320/118, 320/120, 320/122
• US Class Current: 1/1
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An electric energy storage system is designed to equally utilize electric energy storage banks during charging/discharging, and keep fluctuation of an input voltage from a charger or an output voltage to a load, within an arbitrary range, while equally utilizing the electric energy storage banks during charging/discharging. The electric energy storage system comprises an electric energy storage module, a charger, a balancing circuit, a voltage detection section, taps led out, respectively, from one of opposite terminals of the electric energy storage module and/or the other terminal of the electric energy storage module and/or one or more of series-connection points between the electric energy storage units, through respective switches, and a switch control section for switching the switches such that one of the taps is connected to one of opposite terminals of the charger. The switch control section is operable to sequentially switch the switches according to progress of the charging.

Claims

1. An electric energy storage system comprising:

an electric energy storage module having a plurality of electric energy storage units connected in series, each of the plurality of electric energy storage units having one electric energy storage bank or a plurality of electric energy storage banks connected in series;

a charger configured to charge at least one of the electric energy storage banks;

a balancing circuit connected to the electric energy storage module to correct a variation in charged/discharged state between the electric energy storage banks;

a voltage detection section configured to detect a voltage across the electrical energy storage module, across one or more of the electric energy storage banks, or across the charger;

a plurality of taps led out, respectively, from one of opposite terminals of the electric energy storage module, from the other terminal of the electric energy storage module and from one or more of a plurality of series-connection points between the electric energy storage units; and

a switch control section configured to switch switches, wherein at least one of the switches is connected to one of the opposite terminals of the electric energy storage module, to the other terminal of the electric energy storage module, or to at least one of the plurality of series-connection points, the switch control section configured to allow one of the plurality of taps to be connected to one of opposite terminals of the charger, the switch control section being operable, during a charging period, to sequentially switch the switches according to progress of the charging, based on a detection result from the voltage detection section, the switch control section configured to control a first number of at least one of the plurality of electric energy storage units to bypass the charger and be charged via the balancing circuit when a second number of at least one of the plurality of electric energy storage units bypasses the balancing circuit and is charged directly from the charger.

2. The electric energy storage system as defined in claim 1,

wherein the switch control section is configured to switch the switches such that one of the plurality of taps is connected to one of opposite terminals of the charger and another of the plurality of taps is connected to the other terminal of the charger.

3. The electric energy storage system as defined in claim 2, wherein the switch control section is operable, after switching the switches for a predetermined number of times, with respect to each of a plurality of groups set by grouping the plurality of electric energy storage units, to subsequently sequentially switch the switches according to progress of the charging, based on a detection result from the voltage detection section and in a time division manner, so as to control a number of at least one of the plurality of electric energy storage units to be charged not via the balancing circuit but directly from the charger.

4. The electric energy storage system as defined in claim 2, wherein the switch control section is operable, with respect to each of a plurality of groups set by grouping the plurality of electric energy storage units, to sequentially switch the switches according to progress of the charging, based on a detection result from the voltage detection section and in a time division manner, so as to control a number of at least one of the plurality of electric energy storage units to be charged not via the balancing circuit but directly from the charger.

5. The electric energy storage system as defined in claim 3, wherein the switch control section is further operable to perform one or more times, after switching the switches for a predetermined number of times, with respect to each of groups set by re-grouping the plurality of electric energy storage units such that the number of the groups set by the re-grouping is greater than the number of the groups after switching the switches for the predetermined number of times, subsequent sequential switching of the switch according to progress of the charging, based on a detection result from the voltage detection section and in a time division manner, so as to control a number of at least one of the plurality of electric energy storage units to be charged not via the balancing circuit but directly from the charger.

6. The electric energy storage system as defined in claim 4, wherein the switch control section is further operable to perform one or more times, after switching the switches for a predetermined number of times, with respect to each of groups set by re-grouping the plurality of electric energy storage units such that the number of the group set by the re-grouping is greater than the number of the group after switching the switches for the predetermined number of times, subsequent sequential switching of the switch according to progress of the charging, based on a detection result from the voltage detection section and in a time division manner, so as to control a number of at least one of the plurality of electric energy storage units to be charged not via the balancing circuit but directly from the charger.

13. The electric energy storage system of claim 1, wherein the switch control section is configured to control the first number of at least one of the plurality of electric energy storage units to be charged, via the balancing circuit, utilizing the second number of at least one of the plurality of electric energy storage units.

7. An electric energy storage system comprising:

an electric energy storage module having a plurality of electric energy storage units connected in series, each of the plurality of electric energy storage units having one electric energy storage bank or a plurality of electric energy storage banks connected in series;

a load to which electric energy is to be supplied from at least one of the electric energy storage banks;

a balancing circuit connected to the electric energy storage module to correct a variation in charged/discharged state between the electric energy storage banks;

a voltage detection section configured to detect a voltage across the electrical energy storage module, across one or more of the electric energy storage banks, or across the load;

a plurality of taps led out, respectively, from one of opposite terminals of the electric energy storage module, from the other terminal of the electric energy storage module and from one or more of a plurality of series-connection points between the electric energy storage units; and

a switch control section configured to switch switches, wherein at least one of the switches is connected to one of the opposite terminals of the electric energy storage module, to the other terminal of the electric energy storage module, or to at least one of the plurality of series-connection points, the switch control section configured to allow one of the plurality of taps to be connected to one of opposite terminals of the load, the switch control section being operable, during a discharging period, to sequentially switch the switches according to the discharged state, by sequentially turning on one switch at a time or by sequentially turning on a pair of switches at a time, based on a detection result from the voltage detection section, the switch control section configured to control a first number of at least one of the plurality of electric energy storage units to bypass the load and be discharged via the balancing circuit when a second number of at least one of the plurality of electric energy storage units bypasses the balancing circuit and is discharged directly to the load.

8. The electric energy storage system as defined in claim 7,

wherein the switch control section is configured to switch the switches, the switch control section configured to allow one of the plurality of taps to be connected to one of opposite terminals of the load by a first switch of the switches and another of the plurality of taps to be connected to the other terminal of the load by a second switch of the switches.

9. The electric energy storage system as defined in claim 8, wherein the switch control section is operable, with respect to each of a plurality of groups set by grouping the plurality of electric energy storage units, to sequentially switch the switches according to the discharged state, based on a detection result from the voltage detection section and in a time division manner, so as to control a number of at least one of the plurality of electric energy storage units to be discharged from at least one of the electric energy storage units not via the balancing circuit but directly to the load.

10. The electric energy storage system as defined in claim 9, wherein the switch control section is further operable to perform one or more times, after switching the switches for a predetermined number of times, with respect to each of at least one group set by re-grouping the plurality of electric energy storage units such that the number of the at least one group set by the re-grouping is less than the number of the groups after switching the switches for the predetermined number of times, at least one subsequent sequential switching of the switches according to the discharged state, based on a detection result from the voltage detection section and in a time division manner, so as to control a number of at least one of the plurality of electric energy storage units to be discharged from at least one of the electric energy storage units not via the balancing circuit but directly to the load.

14. The electric energy storage system of claim 7, wherein:

the one switch is among a group of switches, each switch of the group of switches comprising a terminal connected to one terminal of the opposite terminals of the load,

a first switch of the pair of switches is among a first group of switches, each switch of the first group of switches comprising a first terminal connected to a first one of the opposite terminals of the load, and

a second switch of the pair of switches is among a second group of switches, each switch of the second group of switches comprising a second terminal connected to a second one of the opposite terminals of the load.

11. An electric energy storage system comprising:

an electric energy storage module having a plurality of electric energy storage units connected in series, each of the plurality of electric energy storage units having one electric energy storage bank or a plurality of electric energy storage banks connected in series;

a charger configured to charge at least one of the electric energy storage banks;

a balancing circuit connected to the electric energy storage module to correct a variation in charged/discharged state between the electric energy storage banks;

a voltage detection section configured to detect a voltage across the electrical energy storage module, across one or more of the electric energy storage banks, or across the charger;

a plurality of taps led out, respectively, from one of opposite terminals of the electric energy storage module, from the other terminal of the electric energy storage module and from one or more of a plurality of series-connection points between the electric energy storage units; and

a switch control section configured to switch switches, wherein at least one of the switches is connected to one of the opposite terminals of the electric energy storage module, to the other terminal of the electric energy storage module, or to at least one of the plurality of series-connection points, the switch control section configured to allow one of the plurality of taps to be connected to one of opposite terminals of the charger and another of the plurality of taps to be connected to the other terminal of the charger, the switch control section being operable, with respect to each of a plurality of groups set by grouping the plurality of electric energy storage units, to sequentially switch the switches, by sequentially turning on a pair of switches at a time, the switch control section configured to repeatedly charge the same at least one electric energy storage unit directly from the charger when a remaining number of electric energy storage units is charged via the balancing circuit, in a time division manner.

12. An electric energy storage system comprising:

an electric energy storage module having a plurality of electric energy storage units connected in series, each of the plurality of electric energy storage units having one electric energy storage bank or a plurality of electric energy storage banks connected in series;

a load to which electric energy is to be supplied from at least one of the electric energy storage banks;

a balancing circuit connected to the electric energy storage module to correct a variation in charged/discharged state between the electric energy storage banks;

a voltage detection section configured to detect a voltage across the electrical energy storage module, across one or more of the electric energy storage banks, or across the load;

a plurality of taps led out, respectively, from one of opposite terminals of the electric energy storage module, from the other terminal of the electric energy storage module and from one or more of a plurality of series-connection points between the electric energy storage units; and

a switch control section configured to switch switches, wherein at least one of the switches is connected to one of the opposite terminals of the electric energy storage module, to the other terminal of the electric energy storage module, or to at least one of the plurality of series-connection points, the switch control section configured to allow one of the plurality of taps to be connected to one of opposite terminals of the load and another of the plurality of taps to be connected to the other terminal of the load, the switch control section being operable, with respect to each of a plurality of groups set by grouping the plurality of electric energy storage units, to sequentially switch the switches, by sequentially turning on a pair of switches at a time, the switch control section configured to repeatedly discharge the same at least one electric energy storage unit directly to the load when a remaining number of electric energy storage units is discharged via the balancing circuit, in a time division manner.