JP2002084668A - Battery pack - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the value of the equivalent charging current of a storage battery module easily by changing the wiring of the primary winding of a flyback transformer with as little structure as possible to be added to the storage battery module. Provided is an assembled battery having a fixed charging circuit. SOLUTION: In an assembled battery in which one or more storage battery cells are connected in series, a flyback transformer 1a, 1b, 1c is provided for each of the storage battery modules 3a, 3b, 3c. When,
Diodes 2a, 2b, 2c are provided, and secondary windings of flyback transformers 1a, 1b, 1c are connected to diodes 2a, 2b.
b, 2c are connected to the anodes and cathodes of the storage battery modules 3a, 3b, 3c, respectively.
3c, flyback transformers 1a, 1b, 1c and diodes 2a, 2b, 2c are fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery in which storage battery modules are connected in series, each of which has a flyback transformer and a diode.

[0002]

2. Description of the Related Art A battery pack in which a plurality of storage battery modules are connected in series is used for an electric vehicle or a communication power supply device requiring a high voltage. When a plurality of storage battery modules are connected in series, the voltage of each storage battery module is irregularly distributed due to variations in battery characteristics, and overcharge or overdischarge of a specific storage battery module occurs. Therefore,
When a storage battery module is used as an assembled battery, it is necessary to use a combination of storage battery modules with small variations in characteristics.

However, the arrangement of the storage battery modules deteriorates the heat radiation and raises the temperature, which affects the characteristics of the storage battery modules and the degree of deterioration of the storage battery modules used for a long time is not negative. It is difficult. Therefore, in order to reduce the variation in the voltage of each storage battery module, equal charging (charging performed to eliminate the variation in the state of charge that has occurred in each storage battery module of the assembled battery) is required.

[0004] In order to charge the storage battery module equally, typical structures added to the storage battery module include a structure in which a current bypass circuit is added to each storage battery module, and a three-pole contact (C contact) for each storage battery module. A structure in which a capacitor is added between the middle points of the three-pole switch,
Secondary windings from multi-winding transformers (transformers in which a primary winding and a plurality of secondary windings are wound on the same core) having the same number of secondary windings as storage battery modules are applied to individual storage battery modules via diodes. There is a structure to connect.

The structure described in, for example, JP-A-7-23082
No. 9, as disclosed in Japanese Patent Publication No. 9, the voltage of each battery module is detected by an electronic circuit provided separately from the storage battery module, and the amount by which the charging current of the high-voltage storage battery module is divided by the bypass structure is increased. The amount of diverted charging current of the low storage battery module by the bypass structure is reduced, the charging amount of each storage battery module is adjusted, and the voltage of each battery module is equalized.

[0006] The method of [[Switched Capacitor Sys
tem for Automatic Series BatteryEqualization ”, APE
As shown in C'97, pp. 848-854], each storage battery module is connected to a three-pole switch and a structure in which a capacitor is connected to the middle point of the three-pole switch, and is provided separately from the storage battery module. In the circuit, the operation of switching the three-pole switch, charging the capacitor in the high-voltage storage battery module, and discharging to the low-voltage storage battery module is repeated to equalize the voltage of each storage battery module.

The method of [[Balanced Charge of Ser
ies Connected Battery Cells ”, INTELEC '98, pp.311-
315], each winding transformer (a transformer in which one primary winding and a plurality of secondary windings are wound simultaneously on one core) is arranged outside the assembled battery, and the multi-winding transformer The secondary winding is pulled out and connected to the positive electrode and the negative electrode of each storage battery module via a diode to charge each storage battery module.

[0008]

In the above prior art, no consideration has been given to adding a structure to a large number of storage battery modules to achieve low loss and easy even charging to the storage battery modules. However, there are problems that wiring is complicatedly arranged between the storage battery modules, that many circuit elements need to be attached, and that the loss increases.

That is, according to the structure of (1), the current bypass circuit must be a current variable means including a resistance component, and the product of the resistance component and the bypass current becomes a loss of the bypass circuit. This not only increases the loss,
When the bypass circuit is installed in the immediate vicinity of the storage battery module, there is a problem that the storage battery module receives heat generated by the bypass circuit and accelerates deterioration. In addition, when the charging current is supplied in a pulsed manner, the current flows through the storage battery module because the AC impedance is small, and there is a problem that it is difficult to control the current flowing through the bypass circuit.

According to the structure of (1), in order to constitute one three-pole switch, at least two semiconductor switches (for example, two power MOS-FETs) and a drive circuit that insulates and operates these switches are provided. This requires a complicated structure and a large number of parts. Further, when the three-pole switch is switched when the resistance or inductance connected in series to the capacitor is close to zero, there is a problem that an excessive current flows through the contact.

According to the structure of (1), the secondary winding of the multi-winding transformer arranged in a concentrated manner is routed to each storage battery module, so that there is a problem that the wiring becomes long and confused. In addition, since the current energy supplied from the primary winding is stored in one transformer core and distributed to a plurality of storage battery modules, when charging the storage battery module with a large current, the transformer core becomes large and the installation space becomes large. There was a problem of being limited. Further, when the storage battery module and the transformer are separated from each other, there is a problem that the wiring of the secondary winding becomes long, and the voltage drop and the loss increase.

In view of the above situation, the present invention has a small number of structures to be added to a storage battery module, and can easily change the value of the equivalent charging current of the storage battery module simply by changing the wiring of the primary winding of the flyback transformer. An object of the present invention is to provide an assembled battery provided with a uniform charging circuit that can be fixed to a module.

[0013]

In order to achieve the object of the present invention, in an assembled battery comprising a plurality of storage battery modules connected in series with one or more storage battery cells, at least one storage battery module is connected to each of the storage battery modules. A flyback transformer and a diode are provided, and a secondary winding of the flyback transformer is connected to an anode and a cathode of the battery module through the diode, and the flyback transformer and the diode are fixed to the battery module. .

The technique using the conventional flyback transformer is that the primary winding and the secondary winding of the flyback transformer correspond one-to-one, and that one flyback transformer corresponds to one storage battery module. It is different from being provided. Therefore, in the present invention, since it is not necessary to charge a plurality of storage battery modules equally with one flyback transformer, the flyback transformer can be reduced in size and can be fixed to the storage battery module.

It is preferable that a connector that can be easily attached to and detached from the primary winding of the flyback transformer is provided in the above-described battery pack structure, and a structure that connects the primary winding of each flyback transformer in series or in parallel is provided. .

[0016] The conventional technology is that the connection of the primary winding is changed so that the equal charging current of each storage battery module can be easily varied, and the storage battery module can be easily removed only by disconnecting the primary winding. Different in that.

[0017]

According to the present invention, since the flyback transformer is installed close to the storage battery module,
The secondary winding connected to the storage battery module can be shortened. Therefore, there is no need to consider power loss due to voltage drop or resistance. In addition, most of the charging structure of the battery module is located close to the battery module,
It is not necessary to route the secondary winding, and it is possible to connect the secondary winding to the anode and the cathode of the storage battery module in advance, so that the problem of incorrect wiring can be avoided.

In the flyback transformer,
Do not apply current to the secondary winding while applying voltage to the primary winding and exciting current to the transformer (excitation inductance). Structure). Thus, energy is stored as an exciting current in the transformer during this period, and the voltage of the primary winding is cut off, and at the same time, the exciting current flows through the secondary winding of the transformer.

Further, by connecting one or more sets of a flyback transformer and a diode to the storage battery module and connecting the primary windings of the flyback transformer in parallel, it is possible to increase the uniform charging current of the storage battery module, By connecting the lines in series, it becomes possible to charge the storage battery modules having different numbers of battery cells equally.

[0020]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a circuit diagram of an assembled battery according to an embodiment of the present invention. The assembled battery in this example is a storage battery module 3
a, 3b, and 3c respectively have diodes 2a, 2b, and 2c.
And the flyback transformers 1a, 1b, 1c. In this figure, three storage battery modules 3
1 shows an example in which a, 3b, and 3c are connected in series, and also shows an external circuit (switch element 4, drive circuit 5, and DC power supply 6) for charging the storage battery modules 3a, 3b, and 3c. In this figure, capacitors 31a, 31a, 3b, 3c
The reason why the capacitors 31b and 31c are connected is to absorb the pulsating current of the flyback transformer, and the capacitors 31a, 31b and 31c are not necessarily required.

The flyback transformers 1a, 1b, 1c and the diodes 2a, 2b, 2c are provided corresponding to the individual storage battery modules 3a, 3b, 3c with the polarities shown.

This circuit operates so as to store an exciting current in the flyback transformer 1 when the switch element 4 is conducting, and to supply a uniform charging current to the secondary winding when the switching element 4 is not conducting.

FIG. 2 shows a mounting diagram when the flyback transformer 1 and the diode 2 are attached to the storage battery module 3. The flyback transformer 3 is composed of
And a magnetic body 8 and a magnetic body plate 7. This transformer has an air gap portion 12 provided in a part of the magnetic body 8 in order to avoid magnetic saturation, and is fixed to an insulating plate 14 by a resin frame 11. One of the secondary windings of the transformer is connected to the anode side of the storage battery module 3 via the diode 2, and the other secondary winding is connected to the cathode of the storage battery module. A tab 15 is provided on the storage battery module 3, and the tab 15 and the lead 10 on the insulating plate 14 are electrically connected. The insulating plate 14 may be fixed to the storage battery module 3 with a joint, but may be a flyback transformer 1 or a diode 2.
May be fixed to the storage battery module 3 with a tape and fixed with a tube exterior and a plastic case.

FIG. 3 is an overhead view of the configuration of FIG. 2 showing the winding portion and the terminal processing portion of the present invention. The primary winding and the secondary winding in this figure are formed in a spiral form with a plate-shaped conductor, and a connector 19 is connected to the end of the primary winding 18 so as to be connected to another primary winding. Constitute.

FIG. 4 shows two flyback transformers.
This is an example in which the secondary winding 18 is connected in series using a connector 19 and a connection line 21. Since the secondary winding 17 is directly connected to the storage battery module 3, there is no need to route it, and only the primary winding 18 needs to be pulled out, so that the connection is very simple.

As the connector 19, general plug type, rack type and panel type connectors can be used.

FIG. 5 shows a flyback transformer current when two storage battery modules are connected in series. The secondary winding current corresponds to a uniform charging current of each storage battery module. The primary winding current increases when the switch element 4 is turned on, and transfers to the secondary winding when the switch element is turned off. Since the period during which the current flowing through the low-voltage storage battery module flows is longer than the period during which the current flowing through the high-voltage storage battery module flows, the integrated value of the current flowing through the low-voltage storage battery module has a large value. Therefore, as a result of the extra charge of the low-voltage storage battery module, the voltage difference of the storage battery module is gradually eliminated.

FIG. 6 shows a modification of the above embodiment. FIG. 3 shows a circuit diagram of an assembled battery that adjusts a uniform charging current by changing the connection or configuration of a primary winding of a flyback transformer.

In FIG. 6A, the primary windings 30a,
30b and 30c are all connected in parallel. for that reason,
The exciting current of the transformer increases, and the storage battery module 3a,
Increase the equal charging current of 3b, 3c.

In FIG. 6B, flyback transformers 1c-1 and 1c-1 are provided in the lowermost battery module 3c.
This is an example in which two sets of c-2 and diodes 2c-1 and 2c-2 are arranged and connected. According to this example, the lowermost storage battery module 3c can be charged evenly with emphasis.

[0031]

As described above, according to the present invention, since the flyback transformer is installed close to the storage battery module, the secondary winding connected to the storage battery module can be shortened, so that the voltage drop or the like can be reduced. There is no need to consider power loss due to resistance. In addition, since most of the charging structure of the storage battery module is placed close to the storage battery module, it is not necessary to route the secondary winding, and the secondary winding is connected in advance to the anode and the cathode of the storage battery module. This also makes it possible to avoid the problem of incorrect wiring. One or more sets of a flyback transformer and a diode are connected to the storage battery module, and the primary winding of the flyback transformer is connected in parallel to increase the uniform charging current of the storage battery module, and the primary winding is connected in series By doing so, it becomes possible to charge the storage battery modules having different numbers of battery cells equally.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an assembled battery according to an embodiment of the present invention.

FIG. 2 is a side view showing a mounted state of the battery pack according to the embodiment of the present invention.

FIG. 3 is an enlarged plan view showing a mounted state of the battery pack according to the embodiment of the present invention.

FIG. 4 is a plan view of an assembled battery in which primary windings are connected in series according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of an operation of the battery pack according to the embodiment of the present invention.

FIG. 6 is a circuit diagram of an assembled battery according to a modified example of the present invention.

[Explanation of symbols]

 1, 1a, 1b, 1c Flybattery transformer, 2, 2a, 2b, 2c diode, 3, 3a, 3b, 3c storage battery module, 4 switch element, 5 drive circuit, 6 DC power supply, 7 magnetic plate, 8 magnetic Body, 9 Secondary winding lead-out part, 10 Lead, 11 Resin frame, 12 Air gap part, 13 Primary to secondary winding, 14 Insulating plate, 15 Tab, 16 Core middle leg, 17 Secondary winding 18 primary winding, 19 connector, 20 pin terminal, 21 connecting wire, 30a, 30b, 30c primary winding, 31a, 31b, 31c capacitor.

Claims (2)

[Claims] 1. A battery pack comprising a plurality of storage battery modules connected in series with one or more storage battery cells, wherein each of the storage battery modules is provided with at least one flyback transformer and a diode. Wherein the secondary winding is connected to the anode and the cathode of the battery module via the diode, and a flyback transformer and a diode are fixed to the battery module. 2. The battery pack according to claim 1, wherein a connection terminal is provided on a secondary winding of the flyback transformer, and the secondary winding of each flyback transformer is connected in series or in parallel. Battery.