JP2985614B2 - Storage battery device with dry-up detection function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery device having a dry-up detection function including a nickel-cadmium storage battery and the like, and a dry-up detection device for detecting dry-up of the storage battery.

[0002]

2. Description of the Related Art A nickel cadmium storage battery is a secondary battery in which an alkaline electrolyte is filled between a positive electrode and a negative electrode. These electrodes and the electrolyte are housed in a container having a closed structure. However, gas is generated inside during charge and discharge, so gas treatment is required in such a sealed structure,
In particular, the container is provided with a safety valve for releasing a large amount of gas generated during overcharge to the outside. Therefore, in a nickel cadmium storage battery, the electrolytic solution is gradually consumed as it is used. In particular, when overcharging is repeated, a large amount of the electrolytic solution is lost, and the internal resistance becomes abnormally high. If the internal resistance of the nickel-cadmium storage battery rises in this way, the terminal voltage rises due to the voltage drop of the internal resistance even with a small amount of current flowing, so that sufficient current cannot be supplied to the load and It will also be difficult to do. Therefore, some storage battery devices equipped with nickel cadmium storage batteries are provided with a dry-up detection device that detects such an increase in internal resistance as dry-up and determines battery abnormality.

A conventional dry-up detection device measures the terminal voltages of all cells of a nickel-cadmium storage battery connected in series in a storage battery device during charging, and this terminal voltage becomes abnormal due to an increase in the internal resistance of some cells. When it becomes higher, it is determined that dry-up has occurred.

[0004]

However, the terminal voltage of the nickel-cadmium storage battery varies in voltage due to the internal resistance depending on the magnitude of the charging current during charging. For example, when a large charging current is supplied for quick charging, , The terminal voltage also increases. However, the conventional dry-up detection device sets the dry-up threshold voltage, which is the reference for dry-up, to a constant value, and treats a case where the measured terminal voltage exceeds the dry-up threshold voltage as a dry-up. This means that if the charging current is small, this dry-up cannot be reliably detected, and if the charging current is large, a normal one may be erroneously detected as dry-up. There was a problem.

In view of the above circumstances, an object of the present invention is to provide a storage battery device with a dry-up detection function capable of detecting an accurate dry-up based on a dry-up threshold voltage according to a charging current. .

[0006]

According to a first aspect of the present invention, there is provided a storage battery device having a dry-up detection function.
A chargeable storage battery, charging current detection means for detecting a charging current flowing into the storage battery at the time of charging, and a voltage value set in advance as an initial value for determination of dry-up, to a charging current detected by the charging current detection means. The threshold voltage is calculated according to a predetermined conversion procedure in which the larger the charging current is, the higher the voltage value is, and the converted voltage value is calculated as a dry-up threshold voltage for determining dry-up. Means, a terminal voltage detecting means for detecting the terminal voltage of the storage battery during charging, and comparing the terminal voltage detected by the terminal voltage detecting means with the dry-up threshold voltage calculated by the threshold voltage calculating means. Dry-up determining means for determining that dry-up has occurred when the voltage exceeds a dry-up threshold voltage. There.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the storage battery device with a dry-up detection function including a storage battery including a plurality of cells records a rated cell number of the storage battery. Rated cell number recording means and short-circuit cell number detecting means for detecting the number of short-circuited cells among a plurality of cells of the storage battery are provided. A voltage value set in advance as an initial value for is converted based on the charging current detected by the charging current detection means according to a predetermined conversion procedure in which the larger the charging current, the higher the voltage value. The value is calculated as a threshold voltage per cell for determining dry-up, and the number of short-circuit cells is detected from the number of rated cells recorded in the number-of-rated-cells recording means. And it calculates the dry-up threshold voltage from the product of the effective number of cells obtained by subtracting the number of short cells out with the threshold voltage per the one cell.

[0008]

The rechargeable storage battery provided in the storage battery device with the dry-up detection function of the present invention includes all secondary batteries such as nickel cadmium storage batteries.

The charging current detecting means connects, for example, a resistor having an extremely low resistance value to the storage battery in series, and measures a charging current by measuring a voltage drop in the resistor due to a current flowing in the storage battery. Can be detected. The terminal voltage detecting means detects the terminal voltages of the entire plurality of cells of the storage battery during the charging.

The threshold voltage calculating means sets a threshold voltage for determining a dry-up predicted when the charging current is 0 A, for example, as an initial value, and sets the charging voltage detected by the charging current detecting means. Based on the current, the dry-up threshold voltage is calculated according to a predetermined conversion procedure such that the voltage value becomes higher than the initial value as the charging current increases. The dry-up threshold voltage is a maximum terminal voltage that can be obtained when dry-up has not occurred in the storage battery, and changes according to the magnitude of the charging current. The conversion procedure executed by the threshold voltage calculation means includes, in addition to a procedure of performing a predetermined calculation using the charging current as a parameter, a table of a dry-up threshold voltage value set in advance for each charging current value, for example. May be used to determine the dry-up threshold voltage corresponding to the charging current, and the dry-up threshold voltage can be calculated by a method other than the original arithmetic processing. Also, this conversion procedure should not cause a large dry current to obtain a lower dry-up threshold voltage than a small charge current for any two types of charge currents. Specifically, a dry-up threshold voltage of the same value may be obtained for a large or small charging current.

The dry-up determining means compares the terminal voltage with the dry-up threshold voltage. When the terminal voltage exceeds the dry-up threshold voltage, it is determined that dry-up has occurred due to an abnormal increase in the internal resistance of the storage battery.

As a result, according to the storage battery device having the dry-up detection function of the first aspect, the dry-up threshold voltage is calculated in accordance with the magnitude of the charging current, and the detected terminal voltage is used as the dry-up threshold voltage. Since the dry-up is detected by comparing with the voltage, highly reliable detection can be performed regardless of the magnitude of the charging current.

Here, the detection of dry-up is normally executed repeatedly when the ratio of the charged capacity to the rated battery capacity is within a predetermined range. Further, once the dry-up is detected, the subsequent charging is not performed. Do not detect. Therefore, in one charge, the number of times of dry-up detection is up to one. In order to further improve the accuracy of dry-up detection, the terminal voltage is detected multiple times by the terminal voltage detection means and the average value is adopted to eliminate the effects of noise or to detect dry-up multiple times. If not, it is possible to avoid erroneous detection by not adopting it as a valid result.

A second aspect of the present invention relates to a storage battery device having a dry-up detection function which can cope with a short-circuit of some cells in a storage battery including a plurality of cells.
When a cell short circuit occurs, a short circuit occurs between the internal electrodes of the cell. Therefore, when a cell short circuit occurs in some cells of the storage battery, the terminal voltage decreases by the number of the cell short circuits, so even if dry-up occurs again,
The terminal voltage detected by the terminal voltage detection means may be lower than the dry-up threshold voltage.

Therefore, in the storage battery device with a dry-up detection function according to a second aspect, the threshold voltage calculating means first calculates the threshold voltage per cell according to the charging current, and then calculates the threshold voltage from the number of rated cells. The effective cell number is calculated by subtracting the short-circuit cell number, and finally the dry-up threshold voltage is calculated from the product of the effective cell number and the threshold voltage per cell. Therefore, in this case, the dry-up threshold voltage becomes a low value according to the number of short-circuited cells, and dry-up can be determined based on the cell voltage of a normal cell. This also enables accurate detection of this dry-up. The rated cell number is recorded in the rated cell number recording means. Also,
The number of short-circuit cells is detected by the short-circuit cell number detection means by determining the short-circuit state of each cell.

The calculation procedure in the threshold voltage calculation means and the like is not particularly limited as long as the calculation is substantially the same. That is, for example, if the threshold voltage calculating means is 1
The threshold voltage per cell is calculated, and the dry-up determining means obtains the cell voltage by dividing the terminal voltage by the effective cell number obtained by subtracting the short-circuit cell number from the rated cell number. Dry-up detection may be performed depending on whether or not it has exceeded.

Further, in the storage battery device with the dry-up detection function according to the second aspect, the dry-up is determined substantially based on the cell voltage per cell. If you record
The dry-up detection device can be used as it is for other storage battery devices having different rated cell numbers, and a highly versatile detection device can be provided.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 5 show an embodiment of the present invention. FIG. 1 is a flowchart showing the operation of the dry-up detecting process shown in FIG. 2, and FIG. 2 is an operation of an interrupt routine in the microcomputer. FIG. 3 is a block diagram showing the configuration of the storage battery device, and FIG.
FIG. 3 is a diagram showing a relationship between a charging current and a threshold voltage.

The storage battery device of this embodiment will be described in the case where the arithmetic control unit of the dry-up detection device is constituted by a one-chip microcomputer.

As shown in FIG. 3, this storage battery device has a microcomputer board 2 housed in a case together with a nickel cadmium storage battery 1. The nickel cadmium storage battery 1 has a plurality of cells 1a connected in series. The positive electrode is connected to a positive terminal 3 of the storage battery device, and the negative electrode is connected to a negative terminal 5 via a shunt resistor 4. The charging and discharging of the storage battery device is performed through the positive terminal 3 and the negative terminal 5. The shunt resistor 4 is an extremely low-resistance resistor having a resistance value of about several mΩ, and functions as a current detector for detecting the magnitude of the current flowing therethrough. In this storage battery device, a thermostat 6 and a thermistor 7 are arranged in the vicinity of the nickel-cadmium storage battery 1 so that their respective conduction states and resistance values can be read from external terminals.
Since the thermostat 6 is shut off when the temperature rises to a predetermined value or more, the terminal state of charge of the nickel cadmium storage battery 1 can be detected by reading out this conduction state from the outside. Since the resistance value of the thermistor 7 changes according to the temperature of the nickel-cadmium storage battery 1, the resistance value can be read from the outside to be used for detecting the timing of completion of charging and the like.

The microcomputer board 2 is a circuit board on which the microcomputer 2a and its peripheral circuits are mounted. The microcomputer 2a has analog ports AD1 to AD3 for inputting analog signals and performing AD conversion. The terminal voltage of the nickel cadmium storage battery 1 is input to the first analog port AD1 via the terminal voltage input circuit 2b, and the voltage drop due to the charging current of the shunt resistor 4 is input to the second analog port AD2. Is input via the charging current input circuit 2c, and a voltage drop due to the discharging current of the shunt resistor 4 is input to the third analog port AD3 via the discharging current input circuit 2d. Terminal voltage input circuit 2b
Is an interface circuit for converting the terminal voltage of the nickel cadmium storage battery 1 into a voltage range in which AD conversion can be performed by resistance division and sending it to the first analog port AD1. The charging current input circuit 2c and the discharging current input circuit 2d
An inverting amplifier and a non-inverting amplifier that obtain a predetermined gain by applying negative feedback to an operational amplifier (operational amplifier). The inverting amplifier and the non-inverting amplifier convert voltage drops corresponding to a charging current and a discharging current into voltage ranges in which AD conversion can be performed, respectively. Interface circuit for sending the signals to the second and third analog ports AD2 and AD3. However, the charging current input circuit 2c outputs a positive voltage when the charging current flows through the shunt resistor 4,
The discharge current input circuit 2d outputs a positive voltage when a discharge current flows through the shunt resistor 4, and the negative voltage is treated as a current value of 0A. A charging current and a discharging current are separately input to the analog ports AD2 and AD3. As a result, the values of the terminal voltage, the charging current and the discharging current of the nickel cadmium storage battery 1 are input to these analog ports AD1 to AD3, respectively, and are converted into digital signals internally. The value of the terminal voltage input to the first analog port AD1 actually includes the voltage drop of the shunt resistor 4, but this voltage drop can be almost ignored.

The microcomputer 2a has IO ports D0 to D10 for performing digital input / output.
An EEP as an external storage device is connected to the IO ports D0 to D3.
The ROM 2e is connected. The EEPROM 2e is an EEPROM [Electrically Erasable Programmable] which is a nonvolatile semiconductor memory device which can be electrically written.
Read-Only Memory], and the IO ports D0 to D
3, data can be read from and written to the EEPROM 2e. This EEPRO
In M2e, battery information unique to the storage battery device, such as the rated battery capacity and the number of rated cells, is written and stored in advance, and dynamic battery information, such as the number of dry-up detections, is also written and updated as needed. I have. IO ports D4 to D
8 is connected to an LED array 2f having five LEDs [Light Emitting Diodes], and each of the IO ports D4 to D8.
Can be lit arbitrarily. A communication terminal 9 which is an external terminal of the storage battery device is connected to the IO port D9, and communication with a charger or the like can be performed via the communication terminal 9. An operation switch 8 provided with an operation unit on the surface of the storage battery device is connected to the IO port D10 so that the operation of the operation switch 8 can be read.

The microcomputer 2a receives a constant voltage power supply from the nickel cadmium storage battery 1 via a power supply circuit 2g. Also, an AD conversion circuit and EEPROM in the microcomputer 2a are used.
The M2e and the LED array 2f are also supplied with power from the nickel-cadmium storage battery 1 via a power supply circuit (not shown). However, the power supply of the AD conversion circuit and the like is controlled by the microcomputer 2a so as to be supplied only when necessary, so that useless power is not consumed.

The operation of the dry-up detecting device for a storage battery device having the above configuration will be described with reference to the flowcharts of FIGS.

The microcomputer 2a has an internal PR.
The control operation is performed by the CPU [Central Processing Unit] performing input / output of each of the ports AD1 to AD3 and D0 to D10 according to the program stored in the OM [Programmable Read-Only Memory]. The microcomputer 2a has a timer interrupt function therein, and can call a program interrupt routine by a hardware interrupt at each time interval set in the timer. Then, the dry-up detection device is realized by this interrupt routine.

This interrupt routine is set so as to be called at a relatively long time interval T1 in order to suppress power consumption when the control is in a standby state. And when this interrupt routine is called,
As shown in FIG. 2, in the first step (hereinafter referred to as "S"), detection is performed by AD-converting the value of the charging current input to the analog port AD2 (S
1). Next, it is checked whether or not the state of charge has been set (S2). If the state of charge has not been set,
It is determined whether the value of the detected charging current is equal to or more than the charging start current Imin (S3). Then, the charging start current Imin
If it is determined that the current time is less than the above, it indicates that the control is in the normal standby state or another state and charging has not been started, and the interrupt routine is immediately terminated.

Here, when the charging of the storage battery device is started, it is determined that the charging current has become equal to or more than the charging start current Imin in the process of S3 of the interrupt routine called first after that. The interruption time is set to a timer time interval T2 shorter than the timer time T1 (S4), and the charging state is set (S4).
5) The control is shifted from the standby state to the charging state. Then, the charging capacity is calculated by multiplying the detected charging current value by the timer time T2, which is the time interval of the timer interrupt (S6). If the charging capacity calculated here is integrated, it means that the charging current has been integrated over time, so that the charge amount accumulated in the nickel-cadmium storage battery 1 by charging can be detected. Further, at this time, if the charging current is multiplied by a charging efficiency that changes according to the magnitude of the charging current and the number of times of charging, more accurate charging capacity can be calculated. The reason for setting the timer interrupt time in the charging state to the timer time interval T2 shorter than the timer time interval T1 in the standby state is to accurately detect the charging capacity based on the charging current. It is possible to cope with the case where the current is unstable or changes significantly.

When the charge capacity is calculated as described above, the RAM [Random] in the microcomputer 2a is used.
The value of the charging current stored in the Access Memory] and the integrated battery capacity are updated (S7), and a short-circuit cell number detection process and a dry-up detection process are executed (S8, S9).
The update of the value of the charging current in S7 is performed by rewriting the value stored in the RAM to a newly detected value. To update the integrated battery capacity, first, the previously calculated integrated battery capacity read from the RAM is added to the currently calculated charging capacity, and this addition result is used as a new integrated battery capacity as R
This is done by writing to AM.

The process of detecting the number of short-circuited cells in S8 is a process of detecting the number of cells 1a in which a cell short-circuit has occurred among the plurality of cells 1a of the nickel cadmium storage battery 1 and recording the number in the EEPROM 2e. More specifically, first, a predicted cell voltage is calculated by estimating the cell voltage per cell, and the product of the predicted cell voltage and the rated cell number stored in the EEPROM 2e is passed through the terminal voltage input circuit 2b. The number of short-circuit cells is calculated by subtracting the detected terminal voltage and dividing the result of the subtraction by the predicted cell voltage. Since the predicted cell voltage is affected by the charging current, the higher the charging current, the higher the voltage. In addition, the calculated number of short-circuit cells is converted to an integer by truncating the fraction below the decimal point. Further, the number of short-circuit cells can be detected many times, and the maximum number of short-circuit cells having the same value as the predetermined number of times or more can be determined as the effective short-circuit cell number. However, the detection of the number of short-circuit cells is performed only once in one charge, and in the embodiment, the detection is performed when the integrated battery capacity exceeds a predetermined ratio of the rated battery capacity stored in the EEPROM 2e. I have to.

The dry-up detection process in S9 is a process for detecting whether or not dry-up has occurred in any of the plurality of cells 1a of the nickel cadmium storage battery 1. This dry-up detection process is performed as shown in FIG.
First, it is determined whether or not a detected flag described later is set (S21). Next, it is determined whether or not the integrated battery capacity updated by the processing of S7 is equal to or more than R1% of the rated battery capacity (S22). Further, it is determined whether or not this integrated battery capacity is equal to or more than R2% of the rated battery capacity (S
23). And if the detected flag is set,
If the integrated battery capacity is less than R1%, or if the integrated battery capacity is more than R2%, the dry-up detection process in S9 is immediately terminated. However, when the detected flag is not set and the integrated battery capacity is equal to or more than R1% and the integrated battery capacity is less than R2%, the dry-up is detected. Therefore, this dry-up detection is performed only after the charging has progressed to some extent and the integrated battery capacity exceeds R1%.
The process is executed until the charging further proceeds and reaches R2%. This dry-up is detected first by analog port A
The detection is performed by AD converting the value of the terminal voltage input to D1 (S24), and the threshold voltage is read from the internal PROM based on the previously detected charging current value (S25).

In the detection of the terminal voltage in S24, in order to avoid the influence of noise, the value of the terminal voltage input to the analog port AD1 is continuously AD-converted and read a plurality of times.
An average of the remaining values excluding the maximum value and the minimum value of these values is obtained, and this is used as an effective terminal voltage. In addition, the maximum value of the cell voltage that can be taken by one normal cell 1a of the nickel cadmium storage battery 1 during charging, that is, the threshold voltage becomes higher as the charging current is larger. Therefore,
In the present embodiment, the threshold voltage Vth is obtained by approximating the threshold voltage Vth by a linear expression of the charging current I, and calculating the expression Vth = Vth0 + kI. Here, Vth0 is the initial value of the threshold voltage when the charging current I is 0A. K is a positive constant close to zero. Accordingly, the relationship between the charging current and the threshold voltage is represented by a straight line that rises to the right as shown in FIG. 4, and as the charging current increases, the threshold voltage gradually increases. In the process of S25, the threshold voltage can be calculated by calculating the equation Vth = Vth0 + kI based on the value of the charging current. However, since such an operation puts a heavy load on the microcomputer 2a, a ROM table method for reading out a threshold voltage previously stored in an internal PROM is used here. That is, the charging current is classified into appropriate ranges, and the threshold voltage for the charging current representing each range is calculated in advance and written in the PROM, so that the processing in S25 corresponds to the detected charging current. It is only necessary to read out the threshold voltage of this PROM.

When the threshold voltage is read as described above, a dry-up threshold voltage is calculated based on the threshold voltage (S26), and the dry-up threshold voltage and the previously detected terminal are calculated. The voltage is compared with the voltage (S27).
In step S26, the effective cell number indicating the total number of cells 1a in the nickel cadmium storage battery 1 in which no cell short circuit has occurred is obtained by subtracting the number of short-circuit cells detected in step S8 from the number of rated cells stored in the EEPROM 2e. The dry voltage threshold is calculated by multiplying the effective voltage by the value voltage. If it is determined in step S27 that the terminal voltage has exceeded the dry-up threshold voltage, it is determined that the dry-up has occurred, and that the dry-up has been detected is recorded in the EEPROM 2e (S28). After the completion flag is set (S29),
The dry-up detection process in S9 is completed. As described above, when the dry-up is once detected, the detected flag is set by the processing of S29, and the processing of S21 is performed.
The detection of dry-up is not performed repeatedly in the interrupt routine after this charging. Also, S27
If it is determined that the terminal voltage is equal to or lower than the dry-up threshold voltage in the process (3), no dry-up has occurred, and the dry-up detection process in S9 is immediately terminated.
Note that the recording in the EEPROM 2e in the process of S28 is initialized to 0 times when the storage battery device is shipped from the factory, and is stored in the EEPROM 2e.
The number of times of dry-up detection recorded in a predetermined area of the ROM 2e is incremented and updated each time a dry-up is detected in the process of S27. When the detection of the dry-up is used for the determination of a battery abnormality or the like, in order to take care of the detection, the detection is made effective only when the number of times of the dry-up detection recorded in the EEPROM 2e reaches a predetermined number or more. .

Once charging is started, in the interrupt routine called thereafter, it is determined that the charging state has been set in the process of S2. In this case as well, subsequently, it is determined whether or not the value of the detected charging current is equal to or greater than the charging start current Imin (S10). After executing the processing of S9, the interrupt routine is ended.

The charging operation is completed when the operator removes the storage battery device from the charger or when the charger automatically detects full charge by a -ΔV charging method or the like. When the charging is completed, the charging current is no longer supplied, so that the first interrupt routine shown in FIG.
In this process, it is determined that the charging current has become less than the charging start current Imin. Therefore, the timer interrupt time is returned to the timer time T1 interval (S11), and the charging state and the detection used in the dry-up detection process of S9 are detected. The completion flag is released (S12, S13), the value of the charging current in the RAM is updated to 0A, and the interrupt routine is terminated from S14. Then, the control returns from the charging state to the initial standby state. However, if the remaining capacity at the start of charging is equal to or more than R2% of the rated battery capacity, or if charging is stopped before the integrated battery capacity reaches R1% of the rated battery capacity, the dry-up is performed in the process of S9. No detection is actually performed.

As described above, according to the dry-up detection device for a storage battery device of the present embodiment, dry-up detection is performed by comparing the dry-up threshold voltage obtained in accordance with the charging current with the terminal voltage. Therefore, the dry-up can be accurately detected without being affected by the magnitude of the charging current. In addition, even when a cell short circuit has occurred, the dry-up can be reliably detected. In the present embodiment, substantially 1
Since the dry-up is detected based on the threshold voltage per cell, if the number of rated cells stored in the EEPROM 2e is changed, this microcomputer board 2
Can be used as it is for other storage battery devices having different numbers of cells, and the versatility is high.

[0037]

As is apparent from the above description, according to the storage battery device with the dry-up detection function of the present invention, the dry-up threshold voltage calculated according to the charging current is compared with the actually detected terminal voltage. By doing so, the dry-up is detected, so that the dry-up can be accurately detected without being affected by the magnitude of the charging current.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a flowchart illustrating an operation of a dry-up detection process shown in FIG. 2;

FIG. 2, showing an embodiment of the present invention, is a flowchart illustrating the operation of an interrupt routine in a microcomputer.

FIG. 3, showing an embodiment of the present invention, is a block diagram illustrating a configuration of a storage battery device.

FIG. 4 illustrates an example of the present invention, and is a diagram illustrating a relationship between a charging current and a threshold voltage per cell.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 nickel cadmium storage battery 2 microcomputer board 2 a microcomputer 2 b terminal voltage input circuit 2 c charging current input circuit 2 e EEPROM 4 shunt resistor

Claims (2)

(57) [Claims] 1. A chargeable storage battery, charge current detection means for detecting a charge current flowing into the storage battery at the time of charging, and a charge current detection means for detecting a voltage value set in advance as an initial value for determining dry-up. Based on the detected charging current, conversion is performed in accordance with a predetermined conversion procedure of setting a higher voltage value as the charging current increases, and the converted voltage value is calculated as a dry-up threshold voltage for determining dry-up. A threshold voltage calculating means, a terminal voltage detecting means for detecting a terminal voltage of the storage battery during charging, and a terminal voltage detected by the terminal voltage detecting means and a dry-up threshold voltage calculated by the threshold voltage calculating means. A dry-up determining means for determining that dry-up has occurred when the terminal voltage exceeds a dry-up threshold voltage. Dry-up detection function with a storage battery apparatus, characterized in that. 2. A storage battery device with a dry-up detection function provided with a storage battery comprising a plurality of cells, a rated cell number recording means for recording a rated cell number of the storage battery,
Short-circuit cell number detecting means for detecting the number of cells in which a cell short-circuit has occurred among a plurality of cells of the storage battery is provided, and the threshold voltage calculating means is provided as an initial value for determining dry-up in advance. Based on the charging current detected by the charging current detection means, the set voltage value is converted according to a predetermined conversion procedure in which the larger the charging current is, the higher the voltage value is, and the converted voltage value is determined to be dry-up. And the effective cell number obtained by subtracting the short-circuit cell number detected by the short-circuit cell number detection means from the rated cell number recorded in the rated cell number recording means, and The storage battery device with a dry-up detection function according to claim 1, wherein the dry-up threshold voltage is calculated from a product of the threshold voltage per cell and the product.