Battery parallel-operation circuit and battery system

• US 9,024,585 B2
• Filed: 03/09/2012
• Issued: 05/05/2015
• Est. Priority Date: 08/06/2010
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakashima, Takeshi, Hagihara, Ryuzo, Ike, Takehito, Sugigaki, Chie
• Primary Examiner(s): Fantu, Yalkew
• Application Number:
  US13/416,970
• Publication Number:
  US 20120212062A1
• Time in Patent Office: 1,152 Days
• Field of Search: 320/117
• US Class Current: 320/117
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A first line includes a switching element and is electrically coupled to a branch point and an external load which is electrically connectable to a battery parallel-operation circuit. A second line includes a resistive element, and is electrically coupled to the external load and the branch point. The first line and the second line are each provided in a plurality. The plural first lines are connected in parallel to one another, and the plural second lines are connected in parallel to one another. The branch points are electrically coupled respectively to plural external, connectable battery units.

Claims

1. A battery parallel-operation circuit comprising:

a first line electrically coupled to a branch point and an external load that is electrically connectable to the battery parallel-operation circuit, the first line comprising a switching element; and

a second line electrically coupled to the external load and the branch point, the second line comprising a resistive element;

wherein the battery parallel-operation circuit includes a plurality of the first lines and a plurality of the second lines, the plurality of first lines are electrically coupled in parallel to one another, and the plurality of second lines are electrically coupled in parallel to one another,

wherein a plurality of the branch points are electrically coupled respectively to a plurality of external, connectable battery units,

wherein each of multiple switching elements is electrically coupled to a corresponding one of the battery units, and is connected in series between the external load and the battery unit, and

wherein each of multiple resistive elements is electrically coupled to a corresponding one of the battery units, and is connected in series between the external load and the battery unit.

2. The battery parallel-operation circuit of claim 1, further comprising a controller configured to control the continuity of each of the switching elements.

3. The battery parallel-operation circuit of claim 2, wherein each of the plurality of battery units comprises a voltage detecting portion configured to, either periodically or at any desired timing, detect an output voltage of the battery unit and output output-voltage information.

4. The battery parallel-operation circuit of claim 3, wherein

the controller receives the output-voltage information,

if the difference in output voltages is less than a predetermined threshold, the controller turns on all of the switching elements, and

if the difference in output voltages is not less than the predetermined threshold, the controller turns off either all or some of the switching elements.

5. The battery parallel-operation circuit of claim 3, wherein

the controller receives the output-voltage information,

the controller identifies the battery unit with the largest output voltage among the plurality of battery units, and

the controller turns on the switching element corresponding to the battery unit with the largest output voltage, and turns off the other switching elements.

6. The battery parallel-operation circuit of claim 3, wherein

the plurality of battery units comprise a first to an nth battery unit (n is an integer of 3 or more),

if the output voltage difference of the plurality of battery units is relatively large, the controller groups the first to the nth battery units into a first to an mth sets (m is an integer of 2 or more) on the basis of the output voltages of the battery units,

the controller identifies the set with the largest number of battery units among the first to the mth sets, and

the controller turns on the switching elements corresponding to the battery units in the identified set, and turns off the switching elements corresponding to the battery units in the set other than the identified set.

7. The battery parallel-operation circuit of claim 3, wherein the plurality of battery units comprise a first to an nth battery unit (n is an integer of 3 or more),

if the output voltage difference of the plurality of battery units is relatively large, the controller groups the first to the nth battery units into two sets on the basis of the output voltages of the battery units,

the controller identifies which one of the two sets has a larger number of battery units, and

the controller turns on the switching elements corresponding to the battery units in the identified set, and turns off the switching elements corresponding to the battery units in the other set.

8. The battery parallel-operation circuit of claim 3, wherein

the controller receives the output-voltage information,

if the difference in output voltages is less than or equal to a predetermined threshold, the controller turns on all of the switching elements, and if the difference in output voltages is not less than or equal to the predetermined threshold, the controller turns off either all or some of the switching elements.

9. The battery parallel-operation circuit of claim 1, further comprising:

a plurality of the battery units configured to supply electric current respectively to the plurality of branch points; and

a controller configured to control the continuity of each of the switching elements,

wherein the controller comprises a timer configured to measure a time elapsed after replacement of any of the plurality of battery units, and

wherein the controller controls the continuity of each of the switching elements on the basis of the elapsed time measured by the timer.

10. The battery parallel-operation circuit of claim 9, wherein

on the basis of the elapsed time measured by the timer, the controller turns on all of the switching elements till the measured elapsed time reaches a predetermined time, and

the controller turns off either all or some of the switching elements after the measured elapsed time reaches the predetermined time.

11. The battery parallel-operation circuit of claim 9, wherein, if any of the battery units is replaced before the measured elapsed time reaches the predetermined time, the controller resets the timer and then starts another measurement of the elapsed time.

12. The battery parallel-operation circuit of claim 1, wherein the switching elements are FETs.

13. The battery parallel-operation circuit of claim 12, wherein

the forward direction of a parasitic diode of the discharger FET is directed from the load to the first lines,

the forward direction of a parasitic diode of the charger FET is directed from the power-supply circuit to the first lines, and

the forward direction of a parasitic diode of the FET used as each of the switching elements is directed from the corresponding battery unit to the corresponding first line.

14. The battery parallel-operation circuit of claim 12, wherein

each of the first line comprises a second switching element,

the forward direction of a parasitic diode of the switching element is directed from the corresponding battery unit to the first line, and

the forward direction of a parasitic diode of the second switching element is directed from the first line to the battery unit.

15. The battery parallel-operation circuit of claim 12, further comprising:

a discharger FET connected in series between the load and the first lines;

a power-supply circuit configured to supply charging current to each of the battery units; and

a charger FET connected in series between the power-supply circuit and the first lines.

16. The battery parallel-operation circuit of claim 15, wherein

the plurality of first lines and the plurality of second lines are electrically coupled to each other at a connection point, and

the battery parallel-operation circuit comprises a second-line switching element provided between the connection point and the plurality of second lines and connected in parallel to the charger FET.

17. The battery parallel-operation circuit of claim 1, wherein each of the resistive elements is a thermistor that has a positive temperature characteristic.

18. The battery parallel-operation circuit of claim 1, wherein each of the second lines comprises a switching element.

19. A battery system comprising:

a plurality of battery units;

a battery parallel-operation circuit comprising;

a first line electrically coupled to a branch point and an external load that is electrically connectable to the battery parallel-operation circuit, the first line comprising a switching element; and

a second line electrically coupled to the external load and the branch point, the second line comprising a resistive element;

wherein the battery parallel-operation circuit includes a plurality of the first lines and a plurality of the second lines, the plurality of first lines are connected in parallel to one another, and the plurality of second lines are connected in parallel to one another,

wherein the branch points are electrically coupled respectively to the plurality of battery units,

wherein each of multiple switching elements is electrically coupled to a corresponding one of the battery units, and is connected in series between the external load and the battery unit, and

wherein each of the resistive elements is electrically coupled to a corresponding one of the battery units, and is connected in series between the external load and the battery unit.

20. The battery system of claim 19, wherein each of the battery units is attachable and detachable.