JP2000152515A - Charging/discharging control of multistage connecting secondary battery and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a battery from being degraded for long service life operation with high charging/discharging efficiency. SOLUTION: This charging/discharging controller 1 of a multistage connecting secondary battery consists of a voltage measuring circuit 3, a charger 4, and a monitor and control device 5. The voltage measuring circuit 3 is capable of measuring the respective voltages of the multistage connecting secondary batteries 2 for measurement of the entire voltage. The charger 4 is capable of charging the multistage connecting secondary batteries 2. The monitor and control device 5 takes in the voltage obtained from the voltage measuring circuit 3, determines as a monitor battery 2i a battery which has reached final discharge voltage at the time of discharge in the multistage connecting secondary batteries 2. Once the monitor battery is determined, the monitor and control device 5 takes in the voltage value of the monitor battery and the entire voltage of the secondary batteries 2, makes a charging means 3 perform charging operation when the voltage value reaches charging control voltage or less, and makes the charger 4 stop charging control when the voltage value of the monitor battery has reached charge regulating voltage Vc or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the charging and discharging of a multistage connected secondary battery in which secondary batteries connected in series in multiple stages can be operated with high efficiency and each secondary battery has a long life. Things.

[0002]

2. Description of the Related Art In recent years, in a technical field related to a power supply or a power storage system of a portable device, an electric vehicle, or the like, a high voltage is obtained by connecting secondary batteries in series in multiple stages. The reason for obtaining such a high voltage is to increase the capacity of stored energy and to use the energy efficiently. It should be noted that the term “secondary battery” here refers to a secondary battery cell, a module including a plurality of secondary battery cells, or a group battery including a plurality of such modules.

Incidentally, when charging / discharging a multi-stage connected secondary battery (assembled battery) constituted by connecting a number of secondary batteries in series as described above, the multi-stage connected secondary battery (assembled battery) is constructed. If you want to control each battery individually,
The circuit becomes complicated, and charge / discharge control of these batteries becomes complicated.

However, in the case of a secondary battery such as a lithium battery which does not allow overcharging / overdischarging, the charging / discharging control is individually performed by providing a necessary control circuit while complicating the complexity. I was going.

On the other hand, in the case of a secondary battery such as a lead battery or a nickel-based battery, the total voltage of the multi-stage connected secondary battery (assembled battery) is measured, and the voltage is controlled based on the measured voltage.

By controlling the terminals of the multi-stage connected secondary battery (assembled battery) at all voltages, even if the multi-stage connected secondary battery (assembled battery) is fully charged, the multi-stage connected secondary battery (assembled battery) is not charged. The voltage of each battery constituting a battery (assembled battery) does not exhibit a constant value, has a certain degree of distribution, and a phenomenon in which the charging electric capacity does not match. The reason is that the battery is manufactured to have a capacity equal to or larger than a predetermined capacity value, and the battery is manufactured so as to inevitably allow a distribution of possible charge and discharge electric capacities.

Also, the impedance inside the battery is naturally not uniform due to the manufacturing stage and the temperature environment of the battery. That is, there is a variation in charge / discharge electric capacity and internal impedance between batteries connected in series in multiple stages. For this reason, if the operation of charge / discharge is controlled by measuring only the voltage at both terminals of the entire multi-stage rechargeable battery (assembled battery) connected in series in the multi-stage, the battery that reaches an overcharge / overdischarge state at the end of charge / discharge Was to occur.

[0008]

The conventional charge / discharge control method for a multi-stage connected secondary battery has the following problems.

(1) In the case of a secondary battery such as a lithium battery, it is necessary to provide a necessary control circuit and to individually perform charge / discharge control while permitting the circuit to be complicated. Complicated and sophisticated control requires a great deal of cost for charge / discharge operation control.

(2) In the case of a secondary battery such as a lead battery or a nickel-based battery, although the circuit is simplified, an excess of the individual batteries constituting the multi-stage connected secondary battery (assembled battery) is required. Efficient operation is not possible due to the occurrence of batteries that are discharged / overcharged, and the life is shortened.

(3) Further, among the individual batteries constituting the multi-stage connected secondary battery (assembled battery), a battery having a smaller charge / discharge electric capacity is more likely to be overcharged / overdischarged. In particular, as the number of connection stages increases, finer voltage control of the entire battery becomes more difficult, and a battery that leads to overdischarge / overcharge is more likely to be generated.

(4) In addition, there is a method of operating at a shallow depth of discharge, but this does not allow the performance of the battery to be fully utilized.

Accordingly, an object of the present invention is to provide a multi-stage connection which controls operation of a multi-stage rechargeable battery (assembled battery) at the time of charging, prevents acceleration of the battery deterioration, and has a high charge / discharge efficiency and a long life. It is an object of the present invention to provide a charge and discharge control method and a device for a secondary battery.

[0014]

In order to achieve the above object, a method of controlling charging and discharging of a multi-stage connected secondary battery according to the first aspect of the present invention is directed to a module comprising a secondary battery cell or a plurality of secondary battery cells. Alternatively, in a method of controlling the charge and discharge of a multi-stage connected secondary battery in which a plurality of secondary batteries including a group battery including the module are connected in series in multiple stages,
A first step of determining a battery that has reached a discharge end voltage at the time of discharging among the multi-stage connected secondary batteries as a monitoring battery, and after the monitoring battery is once determined in the first step, the monitoring battery A second charge control unit that performs charge control when the voltage value or the overall voltage of the multi-stage connected secondary battery has reached the charge control voltage or less, and stops the charge control when the voltage value of the monitoring battery has reached the charge regulation voltage or more. Process.

Therefore, attention is paid to the fact that the battery which has reached the discharge voltage regulation earliest at the time of discharging has the smallest discharge capacity,
According to the voltage change of the battery, the multi-stage connected secondary battery (assembled battery) is charged. By specifying the battery, the temperature can be corrected, and the deteriorated battery can be accurately suppressed. As a result, while ensuring sufficient charge and discharge electric capacity of the battery,
The charge / discharge operation control over a long cycle life can be performed with high efficiency without unnecessary overcharge.

According to a second aspect of the present invention, in the charging / discharging control method for a multi-tiered secondary battery according to the first aspect, the first step comprises measuring each voltage value of the multi-tiered secondary battery. When the measured individual voltage value is equal to or less than the discharge regulation voltage of the unit battery, the battery indicating the voltage value is determined as the monitoring battery. In this case, the battery with the smallest charge / discharge electric capacity can be determined as the monitoring battery from the voltage of each battery.

According to a third aspect of the present invention, in the charging / discharging control method for a multi-tiered secondary battery according to the first aspect, the first step is performed by measuring a voltage value of each of the multi-tiered secondary batteries. When the battery that shows the lowest voltage at each measurement voltage is determined, and the total voltage of the multi-stage connected secondary battery is measured, and the total voltage is equal to or less than the voltage obtained by multiplying the discharge regulation voltage value of the unit battery by the number of stages. Then, the battery showing the lowest voltage is determined as a monitoring battery. In this case, the battery showing the lowest voltage among the batteries can be determined as the monitoring battery.

According to a fourth aspect of the present invention, in the charging / discharging control method for a multi-stage connected secondary battery according to the first aspect, the first step comprises measuring each voltage value of the multi-stage connected secondary battery. A battery indicating the lowest voltage is determined for each measured voltage, and when it is detected that the discharge has ended due to a factor other than the voltage, the battery indicating the lowest voltage is determined as the monitoring battery. In this case, when the battery showing the lowest voltage among the batteries is discharged for some reason, this can be determined as the monitoring battery.

According to a fifth aspect of the present invention, a secondary battery including a secondary battery cell or a module including a plurality of secondary battery cells or a group battery including a plurality of such modules is connected in series in multiple stages. In a device for controlling the charging and discharging of the multi-stage connected secondary battery, a voltage measuring unit that can measure the individual voltage of the multi-stage connected secondary battery and can measure the entire voltage, and a charging unit that charges the multi-stage connected secondary battery. Taking in the voltage obtained from the voltage measuring means, and determining, from among the multi-stage connected secondary batteries, a battery that has reached the discharge end voltage at the time of discharging as a monitoring battery, and once the monitoring battery is determined, the monitoring battery When the voltage value or the whole voltage of the multi-stage connected secondary battery is taken in and the voltage value reaches a charge control voltage or lower, the charging means is charged and the monitoring battery is charged. So that and a monitoring control means for stopping the charging control to the charging means when the voltage value reaches or exceeds the charging regulation voltage.

According to the present invention, attention is paid to the fact that the battery which has reached the discharge voltage regulation earliest at the time of discharging has the smallest discharge capacity, the voltage change of this battery can be captured, and these voltages are monitored by the monitoring control means. Then, after determining the monitoring battery, the charger is driven and controlled based on the voltage of the monitoring battery to charge the multi-stage connected secondary battery (assembled battery). Since the battery is specified, temperature correction can be performed, and the battery with the fastest deterioration can be accurately controlled. As a result, the charge / discharge operation control up to a long cycle life can be performed with high efficiency without causing unnecessary overcharge while ensuring sufficient charge / discharge electric capacity of the battery.

According to a sixth aspect of the present invention, in the charge / discharge control apparatus for a multi-stage connected secondary battery according to the fifth aspect, the voltage measuring means captures the individual voltage and the entire voltage of the multi-stage connected secondary battery, And a digital-to-analog converting means for converting the voltage value output from the multiplexer into digital data. In this case, a plurality of input voltages can be combined into one and supplied to the analog-to-digital conversion means to be converted into digital data, which can be input to the monitoring control means.

According to a seventh aspect of the present invention, in the fifth aspect, the voltage measuring means includes an analog-to-digital conversion means for converting each voltage and the entire voltage of the multi-stage connected secondary battery into digital data, respectively, A digital multiplexer capable of outputting digital data from the conversion means as a predetermined number of data. A plurality of battery voltages can be converted into digital data, which can be converted into one or more and input to the monitoring control means.

According to an eighth aspect of the present invention, in the charging / discharging control device for a multi-stage connected secondary battery according to the fifth aspect, the monitoring control means determines whether or not the multi-stage connected secondary battery has reached the discharge end voltage during discharging. A monitoring battery determining means for determining a monitoring battery, and after the monitoring battery is once determined by the monitoring battery determining means, the voltage value of the monitoring battery or the entire voltage of the multi-stage connected secondary battery reaches the charge control voltage or less. Charging control when the voltage value of the monitoring battery has reached or exceeded the charging regulation voltage. In this case, after determining the monitoring battery, the monitoring control means can control the operation of the charging means based on the monitoring battery, thereby controlling the charging.

According to a ninth aspect of the present invention, in the charge / discharge control device for a multi-stage connected secondary battery according to the eighth aspect, the monitoring battery determination means measures each voltage value of the multi-stage connected secondary battery. When the measured individual voltage value is equal to or lower than the discharge regulation voltage of the unit battery, the processing unit determines the battery indicating the voltage value as the monitoring battery. In this case, the battery with the smallest charge / discharge electric capacity can be determined as the monitoring battery from the voltage of each battery.

The invention according to claim 10 is the same as the invention according to claim 8.
In the charging / discharging control device for a multi-stage connected secondary battery, the monitoring battery determining means measures a voltage value of each of the multi-stage connected secondary batteries and determines a battery having the lowest voltage at each measured voltage. Processing means, measuring the overall voltage of the multi-stage connected secondary battery, and when the overall voltage is equal to or less than the voltage obtained by multiplying the discharge regulation voltage value of the unit battery by the number of stages, the battery showing the lowest voltage is monitored by the monitoring battery. And a comparing and determining means. In this case, the battery showing the lowest voltage among the batteries can be determined as the monitoring battery.

The invention according to claim 11 is the invention according to claim 8
In the charging / discharging control device for a multi-stage connected secondary battery, the monitoring battery determination means measures the voltage value of each of the multi-stage connected secondary batteries and determines the battery having the lowest voltage at each measured voltage. The processing means and the judging means for determining the battery having the lowest voltage as the monitoring battery when detecting that the discharge has ended due to factors other than the voltage.
In this case, the battery showing the lowest voltage among the batteries can be determined as the monitoring battery. When a battery showing the lowest voltage among the batteries is discharged for some reason, this can be determined as a monitoring battery.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below in detail based on one embodiment shown in the drawings.

FIGS. 1 to 5 show a charge / discharge control device for a multi-stage connected secondary battery according to an embodiment of the present invention.

This multi-stage connected secondary battery charge / discharge control device 1
1 can control charging and discharging of the multi-stage connected secondary battery 2 as shown in FIG. 1, and is roughly divided into a voltage measuring circuit 3, a charging device 4, and a monitoring control device 5. I have.

Here, the multi-stage connected secondary battery 2 comprises secondary battery cells 21, 22, 23,..., 2n-3, 2n-2, 2n.
-1 and 2n are connected in series in multiple stages.
In addition, the multi-stage connection secondary battery 2 includes the above-described secondary battery cell 21,
22, 23, ..., 2n-3, 2n-2, 2n-1, 1n
Alternatively, although not shown, a module including a plurality of secondary battery cells or a group battery including a plurality of the modules may be used. Each of the secondary battery cells 21, 22, 23,..., 2n-3, 2n-
2, 2n-1 and 2n are connected to the voltage measuring circuit 3.

The voltage measuring circuit 3 calculates the individual voltages V1, V2, V3,..., Vn-3, V
n-2, Vn-1, and Vn are measured and the total voltage V
o can be measured. The measured voltage is supplied as digital data to the monitoring and control device 5.

The terminals of the charging device 4 are connected to both ends of the multi-stage connected secondary battery 2, and the multi-stage connected secondary battery 2 can be charged based on a control signal of the monitoring control device 5. A load 6 is connected to the charging device 4 so that power can be supplied from the multi-stage rechargeable battery 2 to the load 6 when charging is not performed.

The monitoring and control device 5 includes the voltages V1, V2, V3,..., Vn-3, Vn-2, V obtained from the voltage measuring circuit 3.
n-1 and Vn and the voltage Vo are taken as digital data Sv, and the battery which has reached the discharge end voltage at the time of discharging among the multi-stage connected secondary batteries 2 is monitored by the monitoring battery 2i (i indicates an arbitrary battery, and (Not displayed), and once the monitoring battery 2i is determined, the voltage value Vi of the monitoring battery 2i or the entire voltage Vo of the multi-stage connected secondary battery is taken in, and the voltage value reaches the charging control voltage Vs or lower. When charging is performed, the charging device 4 is caused to perform a charging operation, and when the voltage value Vi of the monitoring battery 2i reaches or exceeds the charging regulation voltage Vd, the charging control of the charging device 4 is stopped. The voltage measuring circuit 3 is connected to a digital input terminal of the monitoring control device 5, and a charging device 4 is connected to a digital output terminal of the monitoring control device 5.

FIG. 2 shows a configuration example of the voltage measurement circuit. In FIG. 2, the voltage measuring circuit 3 includes the individual secondary battery cells 21, 22, 23,.
3,2n-2,2n-1,2n voltages V1, V2, V
3,..., Vn−3, Vn−2, Vn−1, Vn and the overall voltage Vo of the multi-stage rechargeable battery 2, and a multiplexer 31 which can select at least one of them and output it as a voltage Vj, An analog-to-digital converter 32 converts the voltage value Vj output from the multiplexer 31 to digital data Sv. Multiplexer 3
Numeral 1 denotes two movable elements connected to two rows of stators, respectively, which are electronically configured and can move the movable element according to a command from the monitoring and control device 5. It should be noted that once the monitoring battery is determined, the multiplexer 31 is controlled by a command from the monitoring control device 5.
Are connected only to the stator to which the monitoring battery is connected and to the stator to which the entire voltage of the multi-stage connected secondary battery 2 is input. The digital data Sv from the analog-to-digital converter 32 is input to the monitoring control device 5.

FIG. 3 shows an example of the configuration of the monitoring control device. In FIG. 3, the monitoring and control device 5 includes a monitoring battery determination unit 51 and a charge monitoring and control unit 52.
Here, the monitoring battery determination means 51 is the multi-stage connected secondary battery 2
The battery that has reached the discharge end voltage Vn at the time of discharging is determined as the monitoring battery 2i. Further, the monitoring control device 5 temporarily controls the monitoring battery 2 by the monitoring battery determination unit 51.
After i is determined, the voltage value Vi of the monitoring battery 2i is determined.
Alternatively, the charging control is performed when the overall voltage Vo of the multi-stage connected secondary battery 2 has reached the discharge regulation voltage Vd or less, and the charge control is stopped when the voltage value of the monitoring battery 2i has reached the charge regulation voltage Vc or more. It is configured as follows.

Here, the monitoring battery determination means 51 first
Multi-stage connected secondary battery cells 21, 22, 23, ..., 2n
−3, 2n−2, 2n−1, 2n
, Vn-3, Vn-2, Vn-1, and Vn are measured, and the measured individual voltages V1, V2, V3,
, Vn-3, Vn-2, Vn-1, and Vn are unit batteries 2.
It is constituted by processing means for determining the battery showing the voltage value when the voltage is equal to or lower than the discharge regulation voltage Vd of i as the monitoring battery 2i.

Next, although not shown, the monitoring battery determining means 51 includes a plurality of connected secondary battery cells 21, 22, 23,
, 2n-3, 2n-2, 2n-1, and 2n, V1, V2, V3, ..., Vn-3, Vn-2, Vn-
, Vn, and each measurement voltage V1, V2, V3,.
Vn-3, Vn-2, Vn-1, Vn, the lowest voltage battery determination processing means for determining the battery having the lowest voltage, and the total voltage Vo of the multi-stage connected secondary battery 2 are measured, and the total voltage Vo is measured.
Are unit secondary battery cells 21, 22, 23, ..., 2n-3,
When the battery voltage is equal to or lower than the voltage (Vd × n) obtained by multiplying the discharge regulation voltage value Vd of 2n−2, 2n−1, 2n by the number of stages n, the battery indicating the minimum voltage Vmin is determined as the monitor battery 2i. And determination means.

Further, although not shown, the monitoring battery determination means 51 includes multi-stage connected secondary battery cells 21, 22, 23,
, 2n-3, 2n-2, 2n-1, and 2n, V1, V2, V3, ..., Vn-3, Vn-2, Vn-
1 and Vn, and a minimum voltage battery determination processing means for determining a battery showing the minimum voltage Vmin at each measured voltage, and a battery showing the minimum voltage when it is detected that the discharge has ended due to factors other than the voltage. It comprises a monitoring battery and a determination means for determining.

The operation of the embodiment configured as described above will be described below with reference to FIGS. 1 to 3 and FIGS. 4 to 6. Here, FIG. 4 shows a flowchart for explaining the overall operation of the present embodiment.

First, each of the secondary battery cells 21, 22, 23,..., 2n-3, 2n-2, 2n-
, Vn-3, V
n−2, Vn−1, Vn and voltage Vo are input to the multiplexer 31. In the multiplexer 31, these voltages V1, V2, V3,..., Vn-3, Vn-2, Vn-
One of the voltages Vj, 1, and Vn and the voltage Vo is selected and given to the analog-to-digital converter 32. The analog-to-digital converter 32 converts the voltage Vj to digital data Sv. This converted digital data Sv
Is input to the monitoring battery determination means 51 of the monitoring control device 5.

The monitoring battery determining means 51 performs a process of determining whether or not the input digital data Sv has reached the discharge end voltage Vn (step S101). The monitoring battery determination means 51 determines whether each of the voltages V1, V2,
V3,..., Vn−3, Vn−2, Vn−1, Vn and the overall voltage Vo are taken in, and a monitoring battery determination process (first step) is executed (S101-S102 in FIG. 4; NO).
This step is performed until the monitoring battery 2i is determined.

The first step (S101-S10 in FIG. 4)
2; NO), once the monitoring battery 2i is determined, the charge monitoring control means 52 gives a command to the multiplexer 31 of the voltage measuring circuit 3 so that the voltage value Vi of the monitoring battery 2i and the multi-stage connected secondary battery 2 only takes in the charge control voltage Vs (discharge regulation voltage Vd or voltage V
(d × n stages) and the comparison process is performed (S103 in FIG. 4).
The voltage value Vi of the monitoring battery 2i or the total voltage Vo of the multi-stage connected secondary battery 2 is equal to the charge control voltage Vs (discharge regulation voltage V
If it does not reach d or the voltage Vd × n stages or less (S104 in FIG. 4; NO), the charge monitoring controller 52 executes the determination process again (S103 in FIG. 4). This process is performed by monitoring the voltage value Vi of the monitoring battery 2i or the multi-stage connected secondary battery 2
Is the charge control voltage Vs (discharge regulation voltage Vd).
Or until the voltage Vd × n stages or less (S1 in FIG. 4)
04; YES), and executed.

When the voltage value Vi of the monitor battery 2i or the total voltage Vo of the multi-stage connected secondary battery 2 has reached the charge control voltage Vs or less (S104 in FIG. 4; YES), the charge monitoring control means 52 determines Switching to discharge (S in FIG. 4)
105).

At the time of discharging, the charge monitoring control means 52 takes in the voltage value Vi of the monitoring battery 2i and executes a comparison process with the discharge regulation voltage Vd (S105 in FIG. 4). The charge monitoring control means 52 determines that the voltage value Vi of the monitoring battery 2i is equal to the discharge regulation voltage V
d (S106 in FIG. 4; NO), the comparison process in the discharge is performed (S105-S10 in FIG. 4).
6; NO).

When the voltage value Vi of the monitoring battery 2i has reached the discharge regulation voltage Vd or less (S106 in FIG. 4; YES), the charge monitoring control means 52 shifts to the charge control in step 103.

FIG. 5 is a flowchart for explaining the details of the operation for determining the monitoring battery. In FIG. 5, the end voltage in the unit of measurement of the multi-stage connected secondary battery 2 (assembled battery) is set to Vd (S201 in FIG. 5). First, the secondary battery cells 21, 22, 23,..., 2n of the multi-stage connected secondary battery 2
−3, 2n−2, 2n−1, 2n
2, V3,..., Vn-3, Vn-2, Vn-1, Vn and the total voltage Vo of the multistage rechargeable battery 2 are measured by a voltage measuring circuit 3.
And the selected voltage Vj
Is converted into digital data Sv by the analog-to-digital conversion means 32 of the voltage measurement circuit 3 and supplied to the monitoring and control device 5.

The monitoring battery determining means 51 of the monitoring control device 5 determines whether or not the digital data Sv is equal to or higher than Vd (S202 in FIG. 5). When the monitoring battery determination unit 51 determines that the digital data Sv is equal to or lower than Vd (S202 in FIG. 5; NO), the monitoring battery determination unit 51 determines the battery 2i that has reached the voltage Vd as the monitoring battery 2i ( S203 in FIG. 5).

On the other hand, when the monitoring battery determining means 51 determines that the digital data Sv is equal to or higher than Vd (FIG. 5).
S202; YES), since the monitored battery determining means 51 of the monitoring control device 5 has taken in the voltage values of each of the multi-stage connected secondary batteries 2 in step 202, the battery showing the lowest voltage is determined from these voltages. (S20 in FIG. 5)
4).

The monitoring battery determination means 51 measures the total voltage Vo of the multi-stage connected secondary battery 2 and calculates the total voltage V
When o is equal to or less than the voltage (Vd × n) obtained by multiplying the discharge regulation voltage value Vd of the unit battery by the number of stages n (S205 in FIG. 5; N
O), the battery showing the lowest voltage is determined as the monitoring battery 2i (S206 in FIG. 5).

Since the battery having the lowest voltage is already known in step 204, the monitoring battery determination means 5
When it is detected that the discharge has ended due to a factor other than the voltage (S207 in FIG. 5; NO), 1 determines the battery having the lowest voltage as the monitoring battery 2i (S206 in FIG. 5).

After the monitoring battery 2i is determined in this manner (S203, S206), as described above, monitoring of discharge (S208 of FIG. 5) and monitoring of charging (S20 of FIG. 5).
9) will be processed. In practice, monitoring of discharging (S208 in FIG. 5) and monitoring of charging (S209 in FIG. 5) are repeatedly performed.

As described above, in the present embodiment, the battery 2i that has reached the discharge voltage Vd earliest at the time of discharging has the smallest discharge capacity, and therefore, according to the voltage change of the battery 2i, the multi-stage connected secondary battery (assembled battery) 2 Is to be charged. By specifying the battery in this way, the temperature of the battery can be corrected, and the deteriorated battery can be accurately suppressed. Then, it is possible to control the charge and discharge operation up to a long cycle life with high efficiency without sufficiently overcharging while sufficiently securing the charge and discharge electric capacity of the battery.

FIG. 6 shows the charging / discharging voltage characteristics of a multi-tiered secondary battery composed of a nickel-metal hydride battery. The horizontal axis represents time [hours], and the vertical axis represents the voltage [V] of the multi-tiered secondary battery. It was taken. As shown by the solid line in FIG. 6, the voltage value of the deteriorated battery in the multi-stage connected secondary battery (assembled battery) 2 rises during charging, exceeds the charging regulation voltage Vc, leads to overcharging, and during discharging, It leads to overdischarge.

Therefore, in the present embodiment, the monitoring battery 2i
6 is indicated by a dashed line in FIG.
The charging / discharging operation is performed by monitoring the voltage curve in the monitoring control device 5. This monitoring battery 2
As shown in FIG. 6, i repeatedly repeats overdischarge and overcharge, but by performing charging / discharging between the discharge regulation voltage Vd and the charge regulation voltage Vc, the battery does not deteriorate and the cycle life is improved. Can be extended.

In the present embodiment, it is desirable to apply a charging method in which charging is performed with a constant current up to the regulation voltage, and thereafter, charging is performed with a constant voltage.

In the above embodiment, the voltage measuring circuit 3
Instead of the multiplexer 31 and one analog-to-digital conversion means 32, the analog-to-digital conversion means for converting the individual voltages and the entire voltage of the multi-stage connected secondary battery into digital data, respectively, and the analog-to-digital conversion means And a digital multiplexer capable of outputting the digital data from the means as a predetermined number of data.

Further, in the above embodiment, the secondary battery cells 21, 22, 23,.
Although the respective voltages of 3, 2n-2, 2n-1, and 2n can be taken into the monitoring and control device 5 through the multiplexer 31 of the voltage measuring circuit 3, instead of this, each of the secondary battery cells 2
1, 22, 23, ..., 2n-3, 2n-2, 2n-1,
Each voltage of 2n may be periodically measured with a voltmeter or the like, and the measured values may be provided to the monitoring control device 5 from the keyboard each time to determine the monitoring battery. In this case, when the monitoring battery 2i is determined, an electrical configuration in which the voltage of the monitoring battery 2i and the entire voltage of the multi-stage rechargeable battery 2 can be input to the monitoring control device 5 through the analog-to-digital conversion means. After that, the monitoring battery 2
The monitoring control device 5 may control the charging device 4 while monitoring i and the like.

[0058]

Next, embodiments of the present invention will be described. This embodiment aims at load leveling and effective use of nighttime power.
The charge / discharge control device for a multi-stage connected secondary battery according to the present invention is applied to a load conditioner of a small power storage device installed in a general home. This load conditioner uses many connected secondary batteries for power storage.
The power output is 3-5 [kW] and the electric capacity is about 30
At [kW], a high voltage of 100 to 200 [V] is required. In order to obtain a high voltage, dozens or more batteries are connected in series to form a multi-stage connected secondary battery (assembled battery) 2. At this time, since the electric capacity of each battery cell constituting the multi-stage connected secondary battery (assembled battery) 2 is not uniform and varies, the charge / discharge control of the multi-stage connected secondary battery in the above-described embodiment is performed. By applying the device, it is possible to prevent the deterioration of the battery from being promoted, and to operate the battery with high charge / discharge efficiency and long life.

[0059]

As described above, according to the charge / discharge control method for a multi-stage connected secondary battery according to the present invention, it is possible to prevent the deterioration of the battery from being promoted and to operate the battery with high charge / discharge efficiency and long life.

Further, according to the charge / discharge control device for a multi-stage connected secondary battery according to the present invention, it is possible to obtain a device which can prevent the deterioration of the battery from being accelerated and can operate with high charge / discharge efficiency and long life.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a charge / discharge control device for a multi-stage connected secondary battery according to the present invention.

FIG. 2 is a block diagram illustrating a configuration example of the voltage measurement circuit.

FIG. 3 is a block diagram illustrating a configuration example of the monitoring control device.

FIG. 4 is a flowchart shown to explain the overall operation of the embodiment.

FIG. 5 is a flowchart shown to explain details of an operation of determining the monitoring battery.

FIG. 6 is a characteristic diagram showing voltage characteristics of charging and discharging of a multi-stage connected secondary battery constituted by the nickel-metal hydride battery.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Charge / discharge control device for multi-stage connected secondary battery 2 Multi-stage connected secondary battery (assembled battery) 3 Voltage measurement circuit (voltage measurement unit) 4 Charging device (charging unit) 5 Monitoring control device (monitoring control unit) 31 Multiplexer 32 Analog Digital conversion means 51 Monitoring battery determination means 52 Charge monitoring control means

Claims (11)

[Claims] 1. A multistage connection secondary battery in which a secondary battery cell or a module including a plurality of secondary battery cells or a secondary battery including a group battery including a plurality of the modules is connected in multiple stages in series. In the method of controlling discharge, a first step of deciding a battery that has reached a discharge end voltage at the time of discharging among the multi-stage connected secondary batteries as a monitor battery,
After the monitoring battery is once determined in the step, the charging control is performed when the voltage value of the monitoring battery or the total voltage of the multi-stage connected secondary battery has reached the charging control voltage or less, and the voltage value of the monitoring battery has been determined. And a second step of stopping the charge control when the voltage of the battery reaches the charge regulation voltage or higher. 2. The first step measures a voltage value of each of the secondary batteries connected in multiple stages, and indicates the voltage value when the measured individual voltage value is equal to or less than the discharge regulation voltage of the unit battery. The charge / discharge control method for a multi-stage connected secondary battery according to claim 1, wherein the battery that has been used is determined as a monitoring battery. 3. The first step is to measure the voltage value of each of the multi-stage connected secondary batteries to determine a battery exhibiting the lowest voltage at each measured voltage, and 2. A battery which measures the voltage and determines the battery showing the lowest voltage as a monitor battery when the total voltage is equal to or less than a voltage obtained by multiplying the discharge regulation voltage value of the unit battery by the number of stages. The charge / discharge control method of the multistage connection secondary battery as described in the above. 4. The first step is to measure a voltage value of each of the multi-stage connected secondary batteries, determine a battery showing the lowest voltage at each measured voltage, and discharge the battery due to factors other than the voltage. 2. The charge / discharge control method for a multi-stage connected secondary battery according to claim 1, wherein a battery showing the lowest voltage is determined as a monitor battery when the end of the battery is detected. 5. A multi-stage connected secondary battery in which a secondary battery cell, a module including a plurality of secondary battery cells, or a secondary battery including a group battery including a plurality of such modules is connected in multiple stages in series. In the device for controlling discharge, voltage measurement means capable of measuring the individual voltage of the multi-stage connected secondary battery and measuring the overall voltage, charging means for charging the multi-stage connected secondary battery, and the voltage measurement means The voltage is fetched, and among the multi-stage connected secondary batteries, the battery that has reached the discharge end voltage at the time of discharging is determined as the monitor battery, and once the monitor battery is determined, the voltage value of the monitor battery or the multi-stage secondary battery is determined. When the entire voltage of the battery is taken and the voltage value reaches the charge control voltage or less, the charging means is charged, and the voltage value of the monitoring battery becomes equal to or more than the charge regulation voltage. A charge / discharge control device for a multi-stage connected secondary battery, comprising: a monitoring control means for stopping charging control of the charging means when the charging time is reached. 6. The voltage measuring means fetches an individual voltage and an entire voltage of the multi-stage rechargeable battery and outputs at least one of the multiplexed voltage and a digital value of the voltage value output from the multiplexor. 6. The charge / discharge control device for a multi-stage connected secondary battery according to claim 5, comprising an analog-to-digital converter for converting data. 7. The voltage measuring means includes an analog-to-digital conversion means for converting each voltage and the entire voltage of the multi-stage connected secondary battery into digital data, and a digital data from the analog-to-digital conversion means for a predetermined number of times. 6. The charge / discharge control device for a multi-stage connected secondary battery according to claim 5, comprising a digital multiplexer capable of outputting data. 8. A monitoring battery determining means for determining, as a monitoring battery, a battery which has reached a discharge end voltage at the time of discharging among the multi-stage connected secondary batteries, and a monitoring battery once determined by the monitoring battery determining means. Is determined, the charge control is performed when the voltage value of the monitoring battery or the total voltage of the multi-stage connected secondary battery has reached the charging control voltage or less, and the voltage value of the monitoring battery has reached the charging regulation voltage or more. 6. The charge / discharge control device for a multi-stage connected secondary battery according to claim 5, further comprising: charge monitoring control means for stopping the charge control when the charging is performed. 9. The monitoring battery determination means measures the voltage value of each of the multi-stage connected secondary batteries, and indicates the voltage value when the measured individual voltage value is equal to or less than the discharge regulation voltage of the unit battery. 9. The charge / discharge control device for a multi-stage connected secondary battery according to claim 8, further comprising processing means for determining the battery that has been used as a monitor battery. 10. The minimum battery cell determination processing means for measuring the voltage value of each of the secondary batteries connected in multiple stages and determining the battery showing the lowest voltage at each measured voltage, A comparison determining means for measuring the overall voltage of the secondary battery, and when the overall voltage is equal to or less than the voltage obtained by multiplying the discharge regulation voltage value of the unit battery by the number of stages, and determining the battery having the lowest voltage as the monitoring battery. 9. The charge / discharge control device for a multi-stage connected secondary battery according to claim 8, comprising: 11. The minimum battery determination processing means for measuring a voltage value of each of the multi-stage connected secondary batteries to determine a battery having the lowest voltage at each measured voltage, 9. The charge / discharge control device for a multi-stage connected secondary battery according to claim 8, further comprising: a judging means for determining a battery having the lowest voltage as a monitor battery when detecting that the discharge has ended due to a factor.