ELECTRICITY STORAGE SYSTEM, METHOD FOR CONTROLLING SECONDARY BATTERY PACKS, AND SECONDARY BATTERY PACK

• US 20150035494A1
• Filed: 11/08/2012
• Published: 02/05/2015
• Est. Priority Date: 01/30/2012
• Status: Active Grant

• Current Assignee: Envision AESC Energy Devices Ltd.
• Original Assignee: NEC Energy Devices, Ltd. (Envision Group /TX/)
• Inventors: Suzuki, Shin
• Granted Patent: US 9,461,484 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy wind motors F03D
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

In an electricity storage system that has a plurality of secondary battery packs, at the time of switching the object that is to be charged from a first secondary battery pack to a second secondary battery pack that has voltage across terminals lower than that of the first secondary battery pack, by causing a current-limiting circuit of the second secondary battery pack to operate, forms a path for the flow of a charging current for charging secondary batteries that are provided in the second secondary battery pack, and starts charging of the second secondary battery pack while limiting the charging current to a fixed value or less by means of the current-limiting circuit.

Claims

1. An electricity storage system comprising:

a plurality of secondary battery packs that are each provided with secondary batteries, a charging switch that turns a charging current that flows on a charging path of said secondary batteries ON and OFF, a discharging switch that turns a discharging current that flows on a discharging path of said secondary batteries ON and OFF, as well as a current-limiting circuit that is connected in parallel to said charging switch and that limits said charging current to a fixed value or less; and

a host device that, when switching a secondary battery pack that is to be charged from a first secondary battery pack to a second secondary battery pack in which voltage across terminals is lower than that of the first secondary battery pack, by causing said current-limiting circuit of said second secondary battery pack to operate, forms a path on which charging current flows for charging secondary batteries that are provided in said second secondary battery pack, starts charging of said second secondary battery pack while limiting said charging current to said fixed value or less by means of said current-limiting circuit, and turns the discharging switch of said first secondary battery pack OFF.

2. The electricity storage system according to claim 1, wherein said host device:

after turning the discharging switch of said first secondary battery pack OFF, turns the charging switch of said second secondary battery pack ON, turns the charging switch of said first secondary battery pack OFF, and then halts the current-limiting operation by said current-limiting circuit of said second secondary battery pack.

3. The electricity storage system according to claim 1, wherein said host device:

when the charged state of said first secondary battery pack reaches a CV region, switches the secondary battery pack that is to be charged from said first secondary battery pack to said second secondary battery pack.

4. A method of controlling secondary battery packs for controlling a charging operation for a plurality of secondary battery packs that are each provided with:

secondary batteries, a charging switch that turns a charging current that flows on a charging path of said secondary batteries ON and OFF, a discharging switch that turns a discharging current that flows on a discharging path of said secondary batteries ON and OFF, as well as a current-limiting circuit that is connected in parallel to said charging switch and that limits said charging current to a fixed value or less;

wherein an information processing device;

when switching a secondary battery pack that is to be charged from a first secondary battery pack to a second secondary battery pack in which the voltage across terminals is lower than that of said first secondary battery pack, by causing said current-limiting circuit of said second secondary battery pack to operate, forms a path on which charging current flows for charging secondary batteries that are provided in said second secondary battery pack, starts charging said second secondary battery pack while limiting said charging current to said fixed value or less by means of said current-limiting circuit, and turns the discharging switch of said first secondary battery pack OFF.

5. The secondary battery pack control method according to claim 4, wherein said information processing device:

after turning the discharging switch of said first secondary battery pack OFF, turns the charging switch of said second secondary battery pack ON, turns the charging switch of said first secondary battery pack OFF, and then halts the current-limiting operation by said current-limiting circuit of said second secondary battery pack.

6. The secondary battery pack control method according to claim 4, wherein said information processing device:

when the charged state of said first secondary battery pack reaches a CV region, switches the secondary battery pack that is to be charged from said first secondary battery pack to said second secondary battery pack.

7. A secondary battery pack comprising:

secondary batteries;

a charging switch that turns a charging current that flows on a charging path of said secondary batteries ON and OFF;

a discharging switch that turns a discharging current that flows on a discharging path of said secondary batteries ON and OFF;

a current-limiting circuit that is connected in parallel with said charging switch and that limits said charging current to a fixed value or less; and

a control unit that controls said charging switch, said discharging switch, and said current-limiting circuit in accordance with instructions from the outside.

8. The secondary battery pack according to claim 7, wherein said current-limiting circuit is a constant-current circuit.

9. The secondary battery pack according to claim 8, wherein said constant-current circuit contains IGBT.

10. The secondary battery pack according to claim 7, wherein said charging switch and said discharging switch are MOS transistors, and these transistors are connected in series.

11. The secondary battery pack according to claim 7, wherein said charging switch and said discharging switch are bipolar transistors, and these bipolar transistors are connected in parallel.

12. The secondary battery pack according to claim 7, wherein said discharging switch is a relay.