Power supply unit, distributed power supply system and electric vehicle loaded therewith

• US 6,917,181 B2
• Filed: 02/19/2004
• Issued: 07/12/2005
• Est. Priority Date: 11/22/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Emori, Akihiko, Miyazaki, Hideki, Kinoshita, Takuya
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US10/780,685
• Publication Number:
  US 20040160209A1
• Time in Patent Office: 509 Days
• Field of Search: 320/104, 320/126, 320/116, 307/10.1
• US Class Current: 320/104
• CPC Class Codes: B60L 53/11 DC charging controlled by the charging station, e.g. mode 4
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/52 Removing gases inside the secondary cell, e.g. by absorption vent plugs or other mechanical arrangements for facilitating escape of gases H01M50/30
• CPC Class Codes: H01M 12/06 with one metallic and one gaseous electrode
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 2250/20 Fuel cells in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A power supply unit with improved charge/discharge operation for use in distributed power supply system or electric vehicles. The power supply unit includes a storage battery comprising a plurality of circuits connected in series. Each of the plurality of circuits includes a first cell group and a second cell group connected in parallel. The first cell group includes lithium secondary cells or electrical double layer capacitors. The second cell group utilizes an electrolyzable electrolytic solution, or is capable of generating recombinable gas. The second cell group may include lead cells, nickel hydrogen cells, nickel cadmium cells and/or fuel cells. A charger/discharger is provided for controlling charge/discharge of the storage battery adapted to charge the storage battery up to a voltage at which the electrolytic solution of the second cell group is electrolyzed, or to a voltage at which the generated gas is recombined.

Claims

1. A power supply unit comprising:

at least one storage battery comprising a plurality of circuits connected in series, each of the plurality of circuits including a first cell group and a second cell group connected in parallel, wherein said second cell group utilizes an electrolyzable electrolytic solution or generates recombinable gas; and

a charger/discharger for controlling charge/discharge of said storage battery adapted to charge said storage battery up to a voltage at which the electrolytic solution of said second cell group is electrolyzed, or to a voltage at which the generated gas is recombined;

wherein the first cell group includes lithium secondary cells or electrical double layer capacitors, and the second cell group includes lead cells, nickel hydrogen cells, nickel cadmium cells or fuel cells.

2. A power supply unit according to claim 1, wherein said first cell group and said second cell group are connected in parallel through a current limiter.

3. A power supply unit according to claim 1, wherein the at least one storage battery comprises a plurality of said storage batteries connected in parallel.

4. A power supply unit according to claim 1, wherein a withstanding voltage of said first cell group is higher than a withstanding voltage of said second cell group.

5. A power supply unit according to claim 1, wherein each of the plurality of circuits includes a plurality of said second cell groups connected in series.

6. A power supply unit according to claim 1, wherein said first cell group and said second cell group share at least one component element.

7. A power supply unit according to claim 6, wherein said shared component element is the electrolytic solution.

8. A power supply unit according to claim 6, wherein at least one of said first cell group and said second cell group has an electrode formed of carbon fiber or carbon nanotube.

9. A power supply unit according to claim 1, wherein:

the first cell group of each of the plurality of circuits is connected to the first cell group of other circuits in series;

the second cell group of each of the plurality of circuits is connected to the second cell group of other circuits in series; and

the first cell group and the second cell group of each of the plurality of circuits are connected with an intermediate terminal.

10. A power supply unit according to claim 5, wherein:

the first cell group of each of the plurality of circuits is connected to the first cell group of other circuits in series;

the second cell group of each of the plurality of circuits is connected to the second cell group of other circuits in series; and

the first cell group and the second cell group of each of the plurality of circuits are connected with an intermediate terminal.

11. A distributed power supply system comprising:

a storage battery comprising a plurality of circuits connected in series, each of the plurality of circuits including a first cell group and a second cell group connected in parallel;

wherein said second cell group utilizes an electrolyzable electrolytic solution or generates recombinable gas;

a first power supply unit including a charger/discharger for controlling charge/discharge of said storage battery and adapted to charge said storage battery up to a voltage at which the electrolytic solution of said second cell group is electrolyzed or a voltage at which the generated gas is recombined; and

a second power supply unit connected to said first power supply unit in parallel;

wherein when said second power supply unit is in power shortage, electric power is supplied from said first power supply unit, and when said second power supply unit has surplus power, said storage battery of said first power supply unit is charged by the surplus power up to a voltage at which the electrolytic solution of said second cell group is electrolyzed or to a voltage at which the generated gas is recombined; and

wherein the first cell group includes lithium secondary cells or electrical double layer capacitors, and the second cell group includes lead cells, nickel hydrogen cells, nickel cadmium cells or fuel cells.

12. A distributed power supply system according to claim 11, wherein said first cell group and second cell group are connected in parallel through a current limiter.

13. A distributed power supply system according to claim 11, comprising a plurality of said storage batteries connected in parallel.

14. A distributed power supply system according to claim 11, wherein a withstanding voltage of said first cell group is higher than a withstanding voltage of said second cell group.

15. A distributed power supply system according to claim 11, wherein each of said parallel circuits is formed to connect in parallel with a plurality of said second cell groups connected in series and said first cell group.

16. A distributed power supply system according to claim 11, wherein said first cell group and second cell group share at least one component element.

17. A distributed power supply system according to claim 16, wherein said shared component element is the electrolytic solution.

18. A distributed power supply system according to claim 16, wherein at least one of said first cell group and second cell group has an electrode formed of carbon fiber or carbon nanotube.

19. A distributed power supply system according to claim 11, further comprising:

a switch for controlling coupling to said first and second power supply units; and

a controller for controlling said switch in accordance with electric power of said second power supply unit;

wherein said controller controls said switch so that either power is supplied from said first power supply unit when said second power supply unit is in power shortage, or said first power supply unit is charged by the surplus power when said second power supply unit has surplus power.

20. A distributed power supply system comprising:

a storage battery comprising a plurality of first circuits and a plurality of second circuits connected in parallel, each of the plurality of first circuits including a plurality of first cell groups connected in series, and each of the plurality of second circuits including a plurality of second cell groups connected in series, said respective first cell groups being connected in parallel with said respective second cell groups with intermediate terminals, wherein said second cell group utilizes an electrolyzable electrolytic solution or generates recombinable gas;

a first power supply unit including a charger/discharger for controlling charge/discharge of said storage battery and adapted to charge said storage battery up to a voltage at which the electrolytic solution of said second cell group is electrolyzed or a voltage at which the generated gas is recombined; and

a second power supply unit connected to said first power supply unit in parallel;

wherein when said second power supply unit is in power shortage, electric power is supplied from said first power supply unit, and when said second power supply unit has surplus power, said storage battery of said first power supply unit is charged by the surplus power up to a voltage at which the electrolytic solution of said second cell group is electrolyzed or a voltage at which the generated gas is recombined; and

wherein each of the first cell groups includes lithium secondary cells or electrical double layer capacitors, and each of the second cell groups includes lead cells, nickel hydrogen cells, nickel cadmium cells or fuel cells.

21. A distributed power supply system according to claim 20, wherein a withstanding voltage of said first cell groups is higher than a withstanding voltage of said second cell groups.