JPH117341A - Power source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain efficient power supply to a load without using a boosting circuit in a power source device using a battery. SOLUTION: The connection of battery cells 1a and 1b is constituted so as to be switched to serial connection or parallel connection by using switches 2a-2c. When a battery cell voltage is sufficiently higher than the driving voltage of a load 3 at the time of initial discharge, the switch 2a is turned on, the switch 2b is turned off, and the switch 2c is turned on so that the parallel connection can be attained, and any wasteful power consumption can be suppressed. On the other hand, when the battery cell voltage is less than the driving voltage of the load 3 due to the consumption of the battery cell, or when the load 3 temporarily necessitates a high voltage, the switch 2a is turned off, the switch 2b is turned on, and the switch 2c is turned off so that the serial connection can be attained. Thus, a necessary power can be supplied to the load 3 without necessitating any boosting circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device used for, for example, a portable electronic device, and more particularly to a power supply device using a battery.

[0002]

2. Description of the Related Art Batteries are widely used as power sources for portable electronic devices, for example. In a battery, an electromotive force is determined by its structure, that is, a cathode / anode electrolyte material and the like, and the voltage of most battery cells decreases with discharge.

For example, a manganese battery has a voltage of 1.5 V or more at the start of discharge, but has a voltage of 0.1 V at the end of discharge.
The voltage is 8 V or less. In a coke-based lithium ion battery, there is a voltage of about 4.2 V when fully charged, but it is about 2.7 V at the end of discharge.

[0004] As described above, since the discharge voltage of a battery is greatly reduced, in a conventional power supply device, a plurality of battery cells are prepared and used in series connection.
A voltage necessary for operating the device is obtained by providing a booster circuit or the like.

[0005]

As described above, conventionally, in a power supply device using a battery, a plurality of battery cells are used in series connection in order to obtain a voltage required for device operation, or For example, a booster circuit was provided.

However, when a plurality of battery cells are used in series connection, there is a problem that power is inefficient and power is wasted, such as wasting power, because there is an excessive voltage at the initial stage of discharging. In this case, if a plurality of battery cells are used in parallel connection, rapid power consumption can be prevented.However, for example, when a lamp is temporarily brightened or when a motor in a stationary state is started, a certain power consumption can be prevented. It is no longer possible to cope with the case where a high voltage is required temporarily for the time.

Further, if a plurality of battery cells are connected in parallel and a booster circuit is used there, a higher voltage can be temporarily obtained by the booster circuit. However, especially in the case of a load of low power consumption type, there is a problem that the power supply efficiency is deteriorated when the booster circuit is used, and further, the battery life is shortened because the booster circuit itself consumes its own power.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and in a power supply device using a battery, a power supply device capable of efficiently supplying power to a load without using a booster circuit is provided. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION The present invention is a power supply device having a plurality of battery cells and supplying a voltage of these battery cells to a load, wherein the connection device connects the battery cells in series or in parallel. Means and switching means for switching the connection configuration of each of the battery cells by the connection means.

According to such a configuration, the connection configuration of each battery cell can be switched to a series connection or a parallel connection. Therefore, when the battery cell voltage is sufficiently higher than the drive voltage of the load, for example, at the beginning of discharging, the connection is made in parallel, and wasteful power consumption can be suppressed. On the other hand, when the battery cell voltage becomes lower than the drive voltage of the load due to exhaustion of the battery cell, or when the load temporarily requires a high voltage, the connection configuration of each battery cell is connected in series. Switch to connection. This makes it possible to supply a necessary voltage to the load without the need for a booster circuit.

When there are at least four or more battery cells, these battery cells are connected in series, in parallel or in series / parallel, and the connection structure of each of the battery cells is further changed as necessary. Switching in multiple stages is also possible.

It is also possible to detect the state of each battery cell or the state of the load, and to automatically switch the connection configuration of each battery cell based on the detection result.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a configuration of a power supply device according to a first embodiment of the present invention. In the first embodiment, there are two battery cells 1a and 1b.
The battery cells 1a and 1b are made of, for example, a manganese battery, and are connected in series or in parallel via switches 2a, 2b, and 2c.

The switches 2a, 2b, 2c are connected to a load 3
Are connected in series. The load 3 is the battery cell 1
a and an electronic device that operates by receiving the voltage of the battery cell 1b. The anode of the battery cell 1a is connected to the contact between the load 3 and the switch 2a, and the cathode of the battery cell 1a is connected to the contact between the switch 2b and the switch 2c. Also,
The cathode of the battery cell 1b is connected to the contact between the load 3 and the switch 2c, and the anode of the battery cell 1b is connected to the contact between the switch 2a and the switch 2b.

By configuring the two battery cells 1a and 1b and the three switches 2a, 2b and 2c in this manner, the ON / OFF of the switches 2a, 2b and 2c is achieved.
Depending on the off state, the battery cells 1a and 1b are connected in series or in parallel.

Here, in the first embodiment, the above 3
The two switches 2a, 2b, and 2c are three-circuit-linked mechanical switches that operate as shown in FIG.
When any one of the two switches 2a, 2b, 2c is operated, the other two switches move in conjunction. By the on / off combination of the three switches 2a, 2b, 2c, the battery cell 1a and the battery cell 1b can be switched to a series connection or a parallel connection as described below.

For example, if the switch 2a is an operation switch and the switch 2a is turned off, the switch 2a is turned off.
b turns on and the switch 2c turns off. In this state, that is, as shown in FIG. 2, “switch 2a: off,
When the switch 2b is on and the switch 2c is off, the battery cells 1a and 1b are connected in series. When the switch 2a is turned on, the switch 2b is turned off,
The switch 2c is turned on. In this state,
As shown in FIG. 2, "switch 2a: on, switch 2
b: off, switch 2c: on, battery cell 1a
And the battery cell 1b are connected in parallel.

Next, the operation of the power supply device configured as described above will be described. Here, the battery cells 1a and 1b are manganese batteries, and the load 3 is a lamp (for example, a rated voltage of 1.8 V).

The manganese battery has a voltage of 1.5 V
There is a voltage before and after. Therefore, initially, the switch 2a
Is turned on (switch 2b: off, switch 2c: on) and the connection configuration of the battery cells 1a and 1b is connected in parallel, the necessary voltage can be supplied to the load 3, and the lamp lights up brightly. .

However, when the battery cell voltage decreases as the battery discharges, for example, to 1 V, the lamp becomes dark. At this time, the switch 2a is turned off (switch 2b: on, switch 2c: off), and the battery cells 1a and 1b
If the connection configuration is switched to the series connection, the required voltage can be supplied to the load 3 and the lamp can be turned on again brightly.

As described above, when the battery cell voltage is sufficient, by connecting the connection configuration of the battery cells 1a and 1b in parallel, unnecessary power consumption can be prevented and the voltage can be supplied to the load 3. .

When the battery cell voltage decreases or when the load 3 needs a temporarily high voltage, the connection configuration of the battery cell 1a and the battery cell 1b is switched to a series connection, so that the load 3 is required. Voltage can be supplied.

By switching the connection configuration of the battery cells in two stages in this manner, the load 3 can be reduced without the need for a booster circuit.
Can be efficiently supplied, and as a result, the life of the battery cells 1a and 1b can be extended.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the first embodiment, two battery cells are used to switch the connection configuration in series or parallel. However, here, four battery cells are used to switch the connection configuration in series or series-parallel. Like that.

The series-parallel connection includes parallel-series connection, and here refers to a state where sets of battery cells connected in series are connected in parallel or a state where sets of battery cells connected in parallel are connected in series. I do.

FIG. 3 is a diagram showing a configuration of a power supply device according to a second embodiment of the present invention. In the second embodiment, there are four battery cells 1a, 1b, 1c, 1d. Among them, the battery cell 1a and the battery cell 1c are used as a series-connected battery in pairs, and similarly, the battery cell 1b and the battery cell 1d are used as a series-connected battery in pairs. These battery cells 1a, 1b, 1c, 1d are, for example, manganese batteries, and are connected in series (four series) or series-parallel (two series, two parallel) via switches 2a, 2b, 2c. .

The switches 2a, 2b and 2c are connected to the load 3
Are connected in series. The load 3 is the battery cell 1
a, 1b, 1c, 1d. The contact between the load 3 and the switch 2a is connected to the anode of the battery cell 1a, and the contact between the switch 2b and the switch 2c is connected to the cathode of the battery cell 1c. Also,
The cathode of the battery cell 1d is connected to the contact between the load 3 and the switch 2c, and the anode of the battery cell 1b is connected to the contact between the switch 2a and the switch 2b.

Thus, the four battery cells 1a, 1
By connecting the switches b, 1c, 1d and the three switches 2a, 2b, 2c, the switches 2a, 2b, 2c are turned on / off.
Depending on the OFF state, the battery cells 1a, 1b, 1c, 1d are connected in series or in series / parallel.

Here, in the second embodiment, the above 3
The two switches 2a, 2b, 2c are mechanical switches of a three-circuit interlocking type that operate as shown in FIG.
When any one of the two switches 2a, 2b, 2c is operated, the other two switches move in conjunction. The combination of ON / OFF of these three switches 2a, 2b, 2c allows the battery cells 1a, 1b, 1
c and 1d can be switched to series connection or series / parallel connection as follows.

For example, if the switch 2a is an operation switch and the switch 2a is turned off, the switch 2a is turned off.
b turns on and the switch 2c turns off. In this state, that is, as shown in FIG. 4, "switch 2a: off,
When the switch 2b is on and the switch 2c is off, the battery cells 1a, 1b, 1c, and 1d are connected in series. When the switch 2a is turned on, the switch 2b is turned off,
The switch 2c is turned on. In this state,
As shown in FIG. 4, "switch 2a: on, switch 2
b: off, switch 2c: on, battery cell 1
a, 1b, 1c and 1d are connected in series and parallel.

The operation of the power supply device thus configured is the same as that of the first embodiment. That is, since the battery cell voltage is sufficient immediately after the start of discharge,
Turn on switch 2a (switch 2b: off, switch 2
c: ON), the battery cell 1a, 1b, 1c, 1d is connected in series / parallel to prevent wasteful power consumption and supply voltage to the load 3.

When the battery cell voltage decreases or when the load 3 needs a temporarily high voltage, the switch 2a is turned off (switch 2b: on, switch 2c: off) and the battery cells 1a, 1b are turned off. , 1c, 1d can be switched to a series connection to supply a necessary voltage to the load 3.

By switching the connection configuration of the battery cells in two stages, a voltage corresponding to the load 3 can be efficiently supplied. As a result, the battery cells 1a, 1b,
The life of 1c and 1d can be extended.

(Third Embodiment) Next, a third embodiment of the present invention will be described. In the first embodiment, the connection configuration is switched in series or in parallel using two battery cells, but here, the connection configuration is switched in series or in parallel using four battery cells. Like that.

The series-parallel connection includes parallel-series connection, and here refers to a state in which a set of battery cells connected in series is connected in parallel or a state in which a set of battery cells connected in parallel is connected in series. I do.

FIG. 5 is a diagram showing a configuration of a power supply device according to a third embodiment of the present invention. In the third embodiment, there are four battery cells 1a, 1b, 1c, 1d. Among them, the battery cell 1a and the battery cell 1c are used as a parallel connection battery in pairs, and similarly, the battery cell 1b and the battery cell 1d are used as a parallel connection battery in pairs. These battery cells 1a, 1b, 1c, 1d are made of, for example, manganese batteries and are connected in series-parallel (two parallel two series) or parallel (four parallel) via switches 2a, 2b, 2c. .

The switches 2a, 2b and 2c are connected to the load 3
Are connected in series. The load 3 is the battery cell 1
a, 1b, 1c, 1d. The contact points between the load 3 and the switch 2a are connected to the anodes of the battery cells 1a and 1c, and the contact points between the switches 2b and 2c are connected to the cathodes of the battery cells 1a and 1c. The battery cell 1b and the cathode of the battery cell 1d are connected to the contact point between the load 3 and the switch 2c, and the battery cell 1 is connected to the contact point between the switch 2a and the switch 2b.
b and the anode of the battery cell 1d are connected.

Thus, the four battery cells 1a, 1
By connecting the switches b, 1c, 1d and the three switches 2a, 2b, 2c, the switches 2a, 2b, 2c are turned on / off.
Depending on the off state, the battery cells 1a, 1b, 1c, 1d are connected in series or parallel.

Here, in the third embodiment, the above 3
The two switches 2a, 2b, and 2c are three-circuit-linked mechanical switches that operate as shown in FIG.
When any one of the two switches 2a, 2b, 2c is operated, the other two switches move in conjunction. The combination of ON / OFF of these three switches 2a, 2b, 2c allows the battery cells 1a, 1b, 1
c and 1d can be switched to series / parallel connection or parallel connection as follows.

For example, if the switch 2a is an operation switch and is turned off, the switch 2b is turned on and the switch 2c is turned off. In this state, that is, as shown in FIG. 6, "switch 2a: off, switch 2b:
When "ON, switch 2c: OFF", battery cells 1a, 1
b, 1c and 1d are connected in series and parallel. Switch 2
When a is turned on, the switch 2b is turned off and the switch 2c is turned on. In this state, that is, as shown in FIG. 6, when “switch 2a: on, switch 2b: off, switch 2c: on”, battery cells 1a, 1b, 1c, 1
d is connected in parallel.

The operation of the power supply device thus configured is the same as that of the first embodiment. That is, since the battery cell voltage is sufficient immediately after the start of discharge,
Turn on switch 2a (switch 2b: off, switch 2
c: ON), by connecting the connection configuration of the battery cells 1a, 1b, 1c, 1d in parallel, wasteful power consumption is prevented and the voltage is supplied to the load 3.

When the battery cell voltage drops or when the load 3 needs a temporarily high voltage, the switch 2a is turned off (switch 2b: on, switch 2c: off) and the battery cells 1a, 1b are turned off. , 1c, 1d can be switched to a series-parallel connection to supply a necessary voltage to the load 3.

By switching the connection configuration of the battery cells in two stages as described above, the load 3 can be reduced without the need for a booster circuit.
Can be supplied efficiently, and as a result, the life of the battery cells 1a, 1b, 1c, 1d can be extended.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. In the first embodiment, the connection configuration is switched in series or parallel by using two battery cells. However, here, the connection configuration is switched in series, parallel, or series-parallel by using four battery cells. To switch to.

The series-parallel connection includes parallel-series connection, and here refers to a state in which a set of battery cells connected in series is connected in parallel or a state in which a set of battery cells connected in parallel is connected in series. I do.

FIG. 7 is a diagram showing a configuration of a power supply device according to a fourth embodiment of the present invention. In the fourth embodiment, there are four battery cells 1a, 1b, 1c, 1d. Among them, the battery cell 1a and the battery cell 1c are used as a battery pack having a switching function as in the first embodiment in a pair, and similarly, the battery cell 1b and the battery cell 1d are paired. It is used as an assembled battery having a switching function as in the first embodiment. These battery cells 1a,
1b, 1c, and 1d are, for example, manganese batteries, and include switches 2a, 2b, and 2c and switches 2d, 2e, and 2f.
And switches 2g, 2h, and 2i, and connected in series (four series), parallel (four parallel), or series-parallel (two series and two parallel) through three sets of switches.

Of these switches, switches 2g,
2 h and 2 i are connected in series to the load 3.
The load 3 is an electronic device that operates by receiving voltages of the battery cells 1a, 1b, 1c, and 1d. This load 3 and switch 2
g, the anode of the assembled battery circuit 11 of the battery cell 1a and the battery cell 1c is connected, and the switch 2h and the switch 2i are connected.
The cathode of the assembled battery circuit 11 is connected to the contact point. The battery cell 1 is connected to the contact between the load 3 and the switch 2i.
The cathode of the assembled battery circuit 12 of b and the battery cell 1d is connected, and the anode of the assembled battery circuit 12 is connected to the contact point between the switch 2g and the switch 2h.

The assembled battery circuit 11 includes two battery cells 1a
And battery cells 1c and switches 2a, 2b, 2c. The switches 2a, 2b, and 2c are connected in series. The switch 2a is connected to the contact between the load 3 and the switch 2g, and the switch 2c is connected to the contact between the switch 2h and the switch 2i. The anode of the battery cell 1a is connected to the contact between the switch 2g and the switch 2a, and the cathode of the battery cell 1a is connected to the contact between the switch 2b and the switch 2c. The cathode of the battery cell 1c is connected to the contact between the switch 2h and the switch 2c, and the battery cell 1 is connected to the contact between the switch 2a and the switch 2b.
The anode of c is connected.

The assembled battery circuit 12 includes two battery cells 1b
And battery cells 1d and switches 2d, 2e and 2f. The switches 2d, 2e, and 2f are connected in series. The switch 2d is connected to the contact between the switch 2g and the switch 2h, and the switch 2f is connected to the contact between the load 3 and the switch 2i. The anode of the battery cell 1b is connected to the contact between the switch 2h and the switch 2d, and the cathode of the battery cell 1b is connected to the contact between the switch 2e and the switch 2f. The cathode of the battery cell 1d is connected to the contact between the switch 2i and the switch 2f, and the battery cell 1 is connected to the contact between the switch 2d and the switch 2e.
The anode d is connected.

Here, in the fourth embodiment, the switches 2a to 2c, the switches 2d to 2f, and the switches 2g to 2i are three-circuit interlocking mechanical switches operating as shown in FIG. If one of them is operated, the other two switches move in conjunction with each other. The switches 2a to 2c and the switches 2d to
By the combination of ON / OFF of 2f and the switches 2g to 2i, the battery cells 1a, 1b, 1c, 1d can be switched to series connection, parallel connection, or series-parallel connection as follows.

For example, when the switches 2a, 2d, and 2g are operating switches and all of them are turned off, the switch states are as shown in the first row of FIG. 8, and the battery cells 1a, 1b, 1c, 1d. Are connected in series. Also, switch 2a, switch 2d, switch 2
When g is all turned on, the switch state is as shown in the second column of FIG. 8, and the battery cells 1a, 1b, 1c, and 1d are connected in parallel. When the switch 2a is turned off, the switch 2d is turned off, and the switch 2g is turned on, the switch state becomes as shown in the third column of FIG. 8, and the battery cells 1a, 1b, 1c, 1d.
Is a series-parallel connection.

The operation of the power supply device thus configured is such that the switch 2a is turned on (switch 2b: off, switch 2c: on) and the switch 2d is turned on since the battery cell voltage is sufficient immediately after the start of discharge. ON (switch 2
e: off, switch 2f: on), switch 2g on (switch 2h: off, switch 2i: on),
By connecting the connection configuration of the battery cells 1a, 1b, 1c and 1d in parallel, useless power consumption is prevented and the voltage is supplied to the load 3.

When the battery cell voltage decreases or when the load 3 needs a temporarily high voltage, the switch 2a is turned off (switch 2b: on, switch 2c: off) and the switch 2d is turned off (switch 2c). 2e: on, switch 2f: off, switch 2g on (switch 2
h: off, switch 2i: on), and battery cell 1
a, 1b, 1c, and 1d are connected in series and parallel, or the switch 2a is turned off (switch 2b: on, switch 2c: off) and the switch 2d is turned off (switch 2e: on, switch 2f: off) ), Switch 2g
Is turned off (switch 2h: on, switch 2i: off) and the connection configuration of the battery cells 1a, 1b, 1c, 1d is switched to series connection, so that a necessary voltage can be supplied to the load 3.

By switching the connection configuration of the battery cells in three stages as described above, a voltage corresponding to the load 3 can be efficiently supplied without the need for a booster circuit. As a result, the battery cells 1a, The life of 1b, 1c and 1d can be extended. Further, in the present embodiment, a three-circuit interlocking switch is used as the connection changeover switch. However, a nine-circuit interlocking type changeover switch at three fixed positions is used in the rearrangement shown in FIG. A similar function may be realized.

In the first to fourth embodiments,
Although the connection configuration in the case of two or four battery cells has been described, the same configuration can be applied even when a plurality of battery cells are used.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. In the first to fourth embodiments, the connection configuration of a plurality of battery cells is manually switched using a mechanical switch. However, the connection configuration is switched by using an electronic switch. Is performed automatically.

FIG. 9 is a diagram showing a configuration of a power supply device according to the fifth embodiment. In the example of FIG. 9, two battery cells 1
2 shows a configuration (a configuration corresponding to FIG. 1) when a and 1b are used. Here, the switches 2a, 2b, 2c are electronic switches, and the on / off operation thereof is controlled by the switching control circuit 4.

The switching control circuit 4 includes the battery cells 1a, 1b
Is monitored, and when the cell voltage is sufficiently higher than the minimum drive voltage of the load 3 at the start of discharge, the connection configuration of the battery cells 1a and 1b is changed to the parallel connection as described with reference to FIG. Controls the switches 2a, 2b, 2c. The discharge of the battery cells 1a and 1b proceeds, and the cell voltage becomes equal to the load 3
, The switching control circuit 4 controls the switches 2a, 2b, 2c so that the connection configuration of the battery cells 1a, 1b becomes the series connection as described in FIG.

Next, a specific configuration for realizing the above-described power supply device will be described. FIG. 10 is a diagram showing a specific configuration for realizing the power supply device according to the fifth embodiment. In the example of FIG. 10, four battery cells 1a, 1
4 shows a configuration (a configuration corresponding to FIG. 3) when b, 1c, and 1d are used. The battery cells 1a to 1d are connected in series (four series) or series-parallel (two series and two parallel) via switches 2a, 2b, and 2c.

The switches 2a, 2b and 2c are connected to the load 3
Are connected in series. The load 3 is the battery cell 1
a, 1b, 1c, 1d. The contact between the load 3 and the switch 2a is connected to the anode of the battery cell 1a, and the contact between the switch 2b and the switch 2c is connected to the cathode of the battery cell 1c. Also,
The cathode of the battery cell 1d is connected to the contact between the load 3 and the switch 2c, and the anode of the battery cell 1b is connected to the contact between the switch 2a and the switch 2b.

Thus, the four battery cells 1a, 1
b, 1c, 1d and the three switches 2a, 2b, 2c, the on / off of the switches 2a, 2b, 2c.
Depending on the OFF state, the battery cells 1a, 1b, 1c, 1d are connected in series or in series / parallel.

Here, in the fifth embodiment, the switches 2a, 2b, 2c are MOS transistor switches. Among them, the switch 2a and the switch 2b are p
The channel type switch 2c is an n-channel type, and its on / off operation is controlled by output signals A, B, and C of the switching control circuit 4, respectively.

FIG. 11 shows the configuration of the switching control circuit 4.
The switching control circuit 4 includes a constant current circuit 21, a constant voltage diode 22, a comparator with hysteresis 23, an inverter circuit 24, and a buffer circuit 25.
The comparator 23 with hysteresis compares the reference voltage generated by the constant voltage diode 22 with the voltage of the battery cell input to the VIN terminal of the switching control circuit 4. The output signal of the comparator 23 is supplied to the switch 2a as the signal A of the switching control circuit 4 via the inverter circuit 24. When the signal A is at "L" level, the switch 2a is turned on.

The output signal of the comparator 23 is supplied to the switch 2b as the signal B of the switching control circuit 4 and to the switch 2c as the signal C via the buffer circuit 25. When the signal B is at "L" level, the switch 2b is turned on, and when the signal C is at "L" level, the switch 2c is turned off.

Next, the operation of the power supply device configured as described above will be described. Here, the battery cells 1a and 1b are manganese batteries or alkaline manganese batteries, and the load 3 is a circuit including a one-chip microcomputer having an operating voltage of 2.0 V or more and 6.0 V or less.

At the initial stage of discharging, the voltage of the assembled battery of each of the battery cells 1a and 1c and the battery cells 1b and 1d is about 3 V, which is input to the VIN terminal of the switching control circuit 4. As shown in FIG. 11, the voltage input to the VIN terminal is compared with a 2.2 V reference voltage by the comparator 23 with hysteresis. In this case, since the input voltage (battery cell voltage) is higher than the reference voltage, the output of the comparator 23 becomes “H” level. Therefore,
An “L” level signal A is output from the switching control circuit 4 to the switch 2 a via the inverter circuit 24. In addition, the “H” level signal B is output to the switch 2b via the buffer circuit 25, and the “H” level signal C is output to the switch 2c.

With these signals A, B, and C, the switch 2a is turned on, the switch 2b is turned off, and the switch 2c is turned on. Therefore, the four battery cells 1a to 1d are connected in series and parallel, and the load 3 is driven at a low voltage of about 3V.

Next, when the battery cells 1a to 1d are exhausted, VI
The case where the N input voltage (battery cell voltage) becomes lower than the above 2.2V reference voltage will be described. The comparator 23 shown in FIG. 11 has a hysteresis for stabilizing the output, and here, the threshold voltage is 2.1 V.
When the VIN input voltage (battery cell voltage) falls below the threshold voltage, the comparator 23 outputs an “L” level signal. Therefore, the switching control circuit 4 outputs an "H" level signal A to the switch 2a via the inverter circuit 24. Further, an “L” level signal B is output to the switch 2b via the buffer circuit 25, and an “L” level signal C is output to the switch 2c.

With these signals A, B and C, the switch 2a is turned off, the switch 2b is turned on, and the switch 2c is turned off. Therefore, the four battery cells 1a to 1d are connected in series, and the voltage applied to the load 3 becomes 4 V or more. Thereby, even if the battery cell voltage decreases, the load 3 can be continuously driven.

As described above, the voltages of the battery cells 1a to 1d are detected, and the switches 2a, 2b,
By controlling the on / off operation of 2c and switching the connection configuration of the battery cells in two stages, a voltage corresponding to the load 3 can be efficiently supplied without the need for a booster circuit. The life of the battery cells 1a, 1b, 1c, 1d can be extended.

Although not particularly described in the fifth embodiment, improvements such as addition of a capacitor for smoothing a voltage and a resistor for preventing overshoot of a signal may be made according to the situation. It is desirable to carry out.

In an application in which the load 3 temporarily requires a high voltage, the switching control circuit 4 monitors the state of the load 3 (for example, a voltage request signal from the load 3), and The connection configuration of 1b may be switched from series-parallel connection to series connection.

In the fifth embodiment, the connection of each battery cell is automatically switched by detecting the voltage of the battery cell. For example, each value of the voltage and current of the battery cell is transmitted to the microcomputer. The connection configuration of each battery cell may be switched based on the remaining capacity of the battery cells by inputting and calculating the remaining capacity of the battery cells.

The automatic switching method described here is applicable to all of the first to fourth embodiments, and is also applicable to other connection configurations.

In the first to fifth embodiments, all the connection changeover switches are controlled manually or by a control circuit. However, some of the switches may be uncontrolled by using a diode or the like. It is possible. In this case, an element such as a Schottky barrier diode with less loss, that is, a forward voltage effect is used.

The configuration at this time is shown in FIG. 12 as a sixth embodiment. 12 differs from FIG. 10 in that a diode 5a is used instead of the switch 2a and a diode 5b is used instead of the switch 2c.

In such a configuration, when the battery cell voltage is high, the signal B is at the "H" level and the switch 2b is cut off, so that the diodes 5a and 5b become forward voltages and conduct, and the diodes 5a and 5b conduct. Connected. On the other hand, when the battery cell voltage drops, the signal B becomes "L" level, and the diodes 5a and 5b become reverse voltages and are cut off. Therefore, the state is switched to the series connection state.

[0078]

As described above, according to the present invention, in a power supply device having a plurality of battery cells and supplying the voltage of these battery cells to a load, the connection configuration of each battery cell is connected in series or in parallel. The connection configuration of each battery cell can be switched according to the state of the battery cell or the state of the load. Thus, efficient power supply to the load can be performed without using a booster circuit. As a result, there is an effect that the life of the battery cell can be extended.

When there are at least four or more battery cells, these battery cells are connected in series, in parallel or in series-parallel. Furthermore, it can be switched in multiple stages.

Further, by detecting the state of each of the battery cells or the state of the load, the connection configuration of each of the battery cells can be automatically switched based on the detection result.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a power supply device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a switch state and a connection configuration of a battery cell in the first embodiment.

FIG. 3 is a diagram showing a configuration of a power supply device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a relationship between a switch state and a connection configuration of battery cells in the second embodiment.

FIG. 5 is a diagram showing a configuration of a power supply device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a relationship between a switch state and a connection configuration of battery cells in the third embodiment.

FIG. 7 is a diagram showing a configuration of a power supply device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between a switch state and a connection configuration of battery cells in the fourth embodiment.

FIG. 9 is a diagram showing a configuration of a power supply device according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a specific configuration for realizing the power supply device according to the fifth embodiment.

FIG. 11 is a diagram showing a configuration of a switching control circuit according to the fifth embodiment.

FIG. 12 is a diagram showing a specific configuration for realizing a power supply device according to a sixth embodiment of the present invention.

[Explanation of symbols]

 1a, 1b: Battery cell 1c, 1d: Battery cell 2a to 2c: Switch 2d to 2i: Switch 3: Load 4: Switching control circuit 5a, 5b: Diode 11: Assembled battery circuit 12: Assembled battery circuit 21: Constant current circuit 22 constant voltage diode 23 comparator 24 inverter circuit 25 buffer circuit

Claims (3)

[Claims] 1. A power supply device having a plurality of battery cells and supplying a voltage of these battery cells to a load, comprising: connecting means for connecting each of the battery cells in series or in parallel; A power supply device comprising: switching means for switching a connection configuration of each battery cell. 2. The connection means, when there are at least four battery cells, connects these battery cells in series, parallel, or series-parallel, and the switching means: The power supply device according to claim 1, wherein a connection configuration of the cells is switched. 3. A detecting means for detecting a state of each of the battery cells or a state of the load, wherein the switching means switches a connection configuration of each of the battery cells based on a detection result of the detecting means. The power supply device according to claim 1, wherein: