JPH0799068A - Storage battery device with the number of short-circuit cell detecting function - Google Patents

Abstract

PURPOSE:To detect the number of short-circuit cells accurately by considering the variation of the cell voltage according to the amount of the charging current. CONSTITUTION:When the charging of a cadmium storage battery 1 is started, a very short sampling cycle T2 is set, the time T2 is multiplied to the charging current input to an analog port AD2 through a charging current input circuit 2c, so as to calculate the charging capacity, and it is integrated. By the charging capacity and the integrated battery capacity, the value of the RAM in a microcomputer 2a is renewed, so as to carry out a short-circuit cell number detecting process. That is, it is decided whether the integrated capacity before the inner RAM is renewed is less than a specific value R% of the rating battery capacity stored in an external memory device EEPROM 2e connected to IO ports Do to D3 of the microcomputer 2a, or whether the integrated capacity after the renewal is more than the rating R%. And when the integrated capacity exceeds the rating R% by the charging, the short-circuit cell number is detected only one time. This can be calculated from the terminal voltage input to the analog port AD1, and the estimated cell voltage read from the inner ROM by the charging current value.

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 with a short-circuit cell number detection function, which includes a nickel-cadmium storage battery or the like and a short-circuit cell number detection device for detecting the number of cells in which a cell short circuit has occurred.

[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 nickel electrode on the positive electrode side and a cadmium electrode on the negative electrode side through a separator. Further, the storage battery device is configured such that a plurality of cells of such nickel-cadmium storage battery are connected in series to obtain a high voltage. In some of the storage battery devices, a short-circuit cell number detection device is provided to detect the number of cells of the nickel-cadmium storage battery in which a cell short circuit has occurred. In addition to this, a dry-up detection device is provided to detect dry-up due to exhaustion of the electrolyte,
In some cases, an integrated battery capacity calculation device is provided so that an integrated battery capacity indicating the battery capacity actually stored in the nickel-cadmium storage battery at that time is calculated at any time.

A cell short circuit is a phenomenon in which acicular metal cadmium is generated in a separator inside a cell of a nickel-cadmium storage battery when the storage battery device is repeatedly charged and discharged, and this short-circuits between positive and negative electrode plates. is there. When such a cell short circuit occurs, the cell is no longer used as a storage battery. Therefore, the short-circuit cell number detection device of the storage battery device measures the terminal voltage of all cells connected in series in the storage battery device during charging, and this terminal voltage becomes abnormally low due to a decrease in internal resistance of some cells. In this case, it is determined that a cell short circuit has occurred, and the number of cells in which this cell short circuit has occurred is detected. In addition, when this cell short circuit occurs in a large number of cells, the storage battery device cannot supply a sufficient voltage, and therefore a battery abnormality is notified to the outside.

The dry-up is a phenomenon in which the internal resistance is abnormally increased due to gasification and exhaustion of the electrolytic solution inside the cell of the nickel-cadmium storage battery due to overcharge or the like. Then, the dry-up detection device of the storage battery device measures the terminal voltage of all cells connected in series in the storage battery device at the time of charging, and when this terminal voltage becomes abnormally high due to an increase in internal resistance of some cells. It is designed to detect this dry-up. Further, if such dry-up occurs even in one cell, the increase in internal resistance makes it difficult for the storage battery device to supply sufficient current, making it difficult to perform charging. Notify outside as battery abnormality.

The integrated battery capacity is, for example, 0 mAmsec (milliampere millisecond) when the nickel cadmium storage battery is in a completely discharged state, and the charge capacity obtained by time integration of the charging current is added at the time of charging and discharged at the time of discharging. It is a value calculated by repeating the integration process of subtracting the discharge capacity obtained by integrating the current over time. Therefore, this integrated battery capacity represents the battery capacity actually stored in the storage battery device at that time, and at the time of charging, it can be used to show the progress of charging by obtaining the ratio to the rated battery capacity. In addition, at the time of discharging, the integrated battery capacity directly indicates the remaining capacity, and the remaining available battery capacity can be notified without performing subsequent charging. However, since the error is accumulated when such integration of the charge capacity and the discharge capacity is repeated, the accumulated battery capacity calculation device of the storage battery device is, for example, one that is completely discharged when the terminal voltage of the nickel-cadmium storage battery becomes equal to or lower than a predetermined voltage. Assuming that
At that time, the integrated battery capacity is reset to 0 mAm second to initialize the integration.

[0006]

However, the terminal voltage of a nickel-cadmium storage battery is affected by the magnitude of the charging current during charging, and if a large charging current is supplied for rapid charging, this terminal voltage Will also rise. However, in the conventional short-circuit cell number detection device, the cell voltage per cell, which is a reference for cell short-circuiting, is set to a constant value, and the measured terminal voltage is equal to this cell voltage and the rated cell number indicating the number of mounted cells. Since the number of short-circuit cells was detected by the number of cells lower than the product of, the number of short-circuit cells was detected excessively when the charging current was small, and this short-circuit was detected when the charging current was large. There was a problem that the number of cells was detected to be smaller than the actual number. And
When the number of short-circuited cells becomes incorrect as described above, a battery abnormality may be erroneously detected.

Further, the dry-up detection device and the integrated battery capacity calculation device calculate the cell voltage per cell by dividing the number of cells of the storage battery device from the measured terminal voltage, and if the cell voltage is a predetermined value or more. For example, when dry-up is detected, if it is less than a predetermined value, the complete discharge state is detected and the integrated battery capacity is reset to 0 mAm second, so the number of cells of the storage battery device used for the calculation is set. It is necessary to set the value obtained by subtracting the number of short-circuited cells that have already caused a cell short-circuit from the rated number of cells. Therefore, if the number of short-circuited cells is inaccurate, there is a problem that the dry-up detection by the dry-up detection device and the complete discharge state detection by the integrated battery capacity calculation device become unreliable. .

In view of the above circumstances, it is an object of the present invention to provide a storage battery device with a short-circuit cell number detection function, which can accurately determine the number of short-circuit cells based on the predicted cell voltage per cell according to the charging current. I am trying.

[0009]

In order to solve the above-mentioned problems, a storage battery device with a short-circuit cell number detecting function according to claim 1 is a rechargeable storage battery comprising a plurality of cells and a charging current flowing into the storage battery at the time of charging. Based on the charging current detection means for detecting, the terminal voltage detection means for detecting the terminal voltage of the storage battery at the time of charging, and the charging current detected by the charging current detection means, a higher voltage value is obtained as the charging current increases. According to the conversion procedure, a predicted cell voltage calculation unit that calculates this voltage value as a predicted cell voltage that predicts the cell voltage per cell, a rated cell number recording unit that records the rated cell number of the storage battery, and a predicted cell voltage calculation unit. The terminal voltage detected by the terminal voltage detection means is subtracted from the product of the predicted cell voltage calculated by and the rated cell number recorded in the rated cell number recording means, and the subtraction result is further calculated. It is characterized in that a number of short cells calculating means for determining a number of short cells divided by the predicted cell voltage.

A storage battery device with a short-circuit cell number detection function according to a second aspect of the present invention is, in addition to the configuration of the first aspect, rounds down the value after the decimal point of the short-circuit cell number calculated by the short-circuit cell number calculation means to make the short-circuit cell number an integer. It is characterized in that a means for converting the number of short-circuit cells into an integer is provided.

[0011]

All rechargeable batteries such as nickel-cadmium rechargeable batteries are included as rechargeable rechargeable batteries equipped in the rechargeable battery device with a short-circuit cell number detection function of the present invention.

The charging current detecting means, for example, has a resistor having an extremely low resistance value connected in series with a storage battery, and measures the voltage drop in the resistor due to the current flowing in the storage battery to measure the charging current. Can be detected. The terminal voltage detecting means detects the terminal voltage of all the plurality of cells of the storage battery at the time of charging.

The predictive cell voltage calculating means calculates the predictive cell voltage based on the charging current detected by the charging current detecting means according to a predetermined conversion procedure for obtaining a higher voltage value as the charging current increases. The predicted cell voltage is a prediction of the cell voltage per cell for cells in which no cell short circuit has occurred, according to the magnitude of the charging current. Therefore,
If the cell short circuit does not occur, the value obtained by multiplying the rated cell number of the storage battery mounted in the storage battery device by the predicted cell voltage should match the terminal voltage detected by the terminal voltage detection means during charging. The rated cell number of this storage battery device is recorded in the rated cell number recording means. Since the rated cell number is fixed for each type of storage battery device, the rated cell number recording means can use a read-only recording means.

The conversion procedure executed by the predictive cell voltage calculating means is, in addition to the procedure of performing a predetermined calculation using the charging current as a parameter, for example, a table of predicted cell voltage values set in advance for each charging current value. It may be a procedure or the like for obtaining a predicted cell voltage corresponding to the charging current by referring to
The predicted cell voltage can be calculated by a method other than the original calculation process. Also, this conversion procedure should not result in a lower predicted cell voltage for a large charging current than for a small charging current for any two types of charging current, but locally. The same predicted cell voltage may be obtained for large and small charging currents.

The short-circuit cell number calculation means first subtracts the terminal voltage detected by the terminal voltage detection means from the product of the predicted cell voltage calculated by the predicted cell voltage calculation means and the rated cell number recorded in the rated cell number recording means. To do. That is, as described above, the subtraction result should be approximately 0 V unless the cell short circuit occurs, but when the cell short circuit occurs, the internal resistance of the cell in which the cell short circuit occurs is almost zero. Since it is 0Ω, the subtraction result shows a large voltage value in proportion to the number of short-circuited cells. Therefore, the short-circuit cell number calculation means can obtain the short-circuit cell number by further dividing the subtraction result by the predicted cell voltage.

As a result, according to the storage battery device with a short-circuit cell number detection function of claim 1, the predicted cell voltage for predicting the cell voltage per cell is calculated according to the magnitude of the charging current,
Since the number of short-circuit cells is calculated from the actual terminal voltage based on this predicted cell voltage, it becomes possible to detect the accurate number of short-circuit cells.

The calculation procedure in the short-circuit cell number calculating means or the like may be of any specific calculation form as long as the calculation is substantially the same. That is, for example, the predicted cell voltage calculation means obtains a predicted terminal voltage that predicts the terminal voltage when all cells are connected in series, and the short circuit cell number calculation means detects the terminal voltage detection means from this predicted terminal voltage. It is also possible to obtain the short-circuited cell number by subtracting the terminal voltage, further dividing the subtraction result by the predicted terminal voltage, and multiplying by the rated cell number recorded in the rated cell number recording means.

Since the number of short-circuited cells detected here does not change frequently, one detection is usually performed only when the charging capacity exceeds a predetermined ratio of the rated battery capacity during charging. Try to do it. Further, in order to further improve the detection accuracy of the number of short-circuited cells, the terminal voltage detection means detects the terminal voltage a plurality of times and adopts the average value thereof to eliminate the influence of noise or detect the short-circuited cells. If the same value is not detected a plurality of times, it is also possible to avoid erroneous detection by not adopting it as a valid result.

According to another aspect of the storage battery device with a short-circuit cell number detecting function, the short-circuit cell number integer conversion means integerizes the short-circuit cell number calculated by the short-circuit cell number calculation means. In the actual calculation by the short-circuited cell number calculation means, a fractional part after the decimal point is usually generated in the result. However, since a cell short circuit is a phenomenon in which positive and negative electrode plates in the cell are short-circuited, it is not considered that the inside of the cells connected in series is further divided and partially short-circuited. Numbers are also usually integers. Therefore, according to the second aspect, the number of short-circuit cells calculated by the short-circuit cell number calculation means is converted into an integer, and the number of short-circuit cells can be obtained as an integer value according to the general concept.

[0020]

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

1 to 5 show an embodiment of the present invention. FIG. 1 is a flow chart showing the operation of the shorted cell number detection processing shown in FIG. 2, and FIG. 2 is an interrupt routine of a microcomputer. Flow chart showing the operation, FIG. 3 is a block diagram showing the configuration of the storage battery device, FIG. 4 is a diagram showing the relationship between the charging current and the predicted cell voltage, and FIG.
6 is a memory map of a recording area for the number of short-circuited cells in a PROM.

In the storage battery device of this embodiment, a case where the arithmetic control unit of the short-circuit cell number detecting device is constituted by a one-chip microcomputer will be described.

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 is formed by connecting a plurality of cells 1a in series, and the positive electrode is connected to the positive electrode terminal 3 of the storage battery device and the negative electrode is connected to the negative electrode terminal 5 via the shunt resistor 4. Then, the storage battery device is charged and discharged through the positive electrode terminal 3 and the negative electrode terminal 5. The shunt resistor 4 is a very low resistance resistor having a resistance value of about several mΩ, and plays a role of a galvanic detector for detecting the magnitude of the current flowing therethrough. Further, 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 the respective conduction states and resistance values can be read from the external terminals.
Since the thermostat 6 is cut off when the temperature rises above a predetermined value, the end of charge of the nickel-cadmium storage battery 1 can be detected by reading 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 thermistor 7 can be used to detect the timing of completion of charging by reading the resistance value from the outside.

The microcomputer board 2 is a circuit board on which the microcomputer 2a and its peripheral circuits are mounted. The microcomputer 2a includes analog ports AD1 to AD3 for inputting analog signals and performing AD conversion. Then, 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 inputted via the charging current input circuit 2c, and the voltage drop due to the discharging current of the shunt resistor 4 is inputted 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 capable of AD conversion by resistance voltage division and sending the voltage range to the first analog port AD1. Further, the charging current input circuit 2c and the discharging current input circuit 2d are
An inverting amplifier and a non-inverting amplifier that obtain a predetermined gain by applying negative feedback to an operational amplifier (operational amplifier), and convert the voltage drop corresponding to the charging current and the discharging current into a voltage range in which AD conversion is possible. Is an interface circuit for sending 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 of each is treated as a current value of 0 A. A charging current and a discharging current are separately input to the analog ports AD2 and AD3. As a result, the terminal voltage, the charging current and the discharging current of the nickel-cadmium storage battery 1 are input to the analog ports AD1 to AD3, respectively, and internally converted into digital signals. 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 digital input / output.
The IO ports D0 to D3 are provided with EEP, which is an external storage device.
The ROM 2e is connected. The EEPROM 2e is an electrically erasable nonvolatile semiconductor memory device such as an EEPROM [Electrically Erasable Programmable].
Read-Only Memory], and these IO ports D0 to D
It is possible to read / write data from / to the EEPROM 2e via 3. This EEPRO
In the M2e, battery information such as the rated battery capacity and the number of rated cells that is unique to the storage battery device is written and stored in advance, and dynamic battery information such as the number of short-circuited cells is also written and updated at any time and stored. . 5 for IO ports D4 to D8
An LED array 2f including a plurality of LEDs [Light Emitting Diodes] is connected so that the LEDs corresponding to the IO ports D4 to D8 can be arbitrarily turned on. 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 having an operation unit provided on the surface of the storage battery device is connected to the IO port D10, and the operation of the operation switch 8 can be read.

The microcomputer 2a is adapted to receive a constant voltage power supply from the nickel-cadmium storage battery 1 via the power supply circuit 2g. In addition, an AD conversion circuit and EEPRO inside the microcomputer 2a
The M2e and the LED array 2f are also adapted to receive power supply from the nickel-cadmium storage battery 1 via a power supply circuit (not shown). However, the power supplies for these AD conversion circuits and the like are controlled by the microcomputer 2a so that the power is supplied only when necessary, so that unnecessary power is not consumed.

The operation of the short-circuited cell number detecting device of the storage battery device having the above configuration will be described with reference to the flowcharts of FIGS. 1 and 2.

The microcomputer 2a has an internal PR
The CPU [Central Processing Unit] performs a control operation by inputting and outputting the ports AD1 to AD3 and D0 to D10 in accordance with a program stored in the OM [Programmable Read-Only Memory]. Further, the microcomputer 2a has a timer interrupt function therein, and can call a program interrupt routine by a hardware interrupt at every time interval set in the timer. The short-circuit cell number detection device is realized by this interrupt routine.

This interrupt routine is set to be called at a relatively long timer time T1 interval in order to suppress power consumption when the control is in the standby state. And when this interrupt routine is called,
As shown in FIG. 2, in the first step (hereinafter referred to as "S"), the value of the charging current input to the analog port AD2 is AD-converted to perform detection (S).
1). Next, it is checked whether or not the charging state is set (S2). If the charging state is not set,
It is determined whether the value of the detected charging current is greater than or equal to the charging start current Imin (S3). Then, the charging start current Imin
If it is determined that the condition is not satisfied, it means that the control is in the normal standby state or another state and that the charging is not started, so 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 higher than the charging start current Imin in the processing of S3 of the interrupt routine that is first called after that. The interrupt time is set to the timer time T2 interval shorter than the timer time T1 (S4), and the charging state is set (S4).
5) The control shifts from the standby state to the charging state. Then, the charge capacity is calculated by multiplying the detected charge 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 is integrated over time, and thus the amount of charge accumulated in the nickel-cadmium storage battery 1 by charging can be detected. Further, at this time, if the charging current is also multiplied by the charging efficiency that changes according to the magnitude of the charging current and the number of times of charging, a more accurate charging capacity can be calculated. In this charging state, the timer interrupt time is set to the timer time T2 interval shorter than the timer time T1 interval in the standby state in order to accurately detect the charging capacity based on the charging current. It is possible to deal with the case where the current is unstable or changes significantly.

When the charge capacity is calculated as described above, the RAM [Random
The value of the charging current and the integrated battery capacity stored in [Access Memory] are updated (S7), and the short-circuit cell number detection process is executed (S8). The value of the charging current in S7 is updated by rewriting the value stored in the RAM with the newly detected value. Further, the cumulative battery capacity is updated by first adding the above-mentioned charge capacity calculated this time to the previous cumulative battery capacity read from the RAM and writing the addition result in the RAM as a new cumulative battery capacity.

The short-circuit cell number detection process of S8 is a process of detecting the number of cells 1a having a cell short circuit among the plurality of cells 1a of the nickel-cadmium storage battery 1 and recording the result in the EEPROM 2e. However, the detection of the number of short-circuit cells is
It is designed to be performed only once with one charge. That is, as shown in FIG.
The accumulated battery capacity before updating due to
It is determined whether or not it is less than R% of the rated battery capacity stored in (S21), and then whether or not the integrated battery capacity after the update by the processing of S7 is R% or more of the rated battery capacity. (S22). If the integrated battery capacity before updating is not less than R% of the rated battery capacity or if the integrated battery capacity after updating is not more than R% of the rated battery capacity,
The process of detecting the number of short-circuited cells in S8 is immediately terminated. However, the integrated battery capacity before updating is less than R% of the rated battery capacity, and the integrated battery capacity after updating is R of the rated battery capacity.
When the total battery capacity exceeds R% of the rated battery capacity by charging, that is, when the total battery capacity is just over%, the number of short-circuit cells is detected only once. The number of short-circuited cells is detected by first AD-converting the value of the terminal voltage input to the analog port AD1 (S23), and predicting it from the internal PROM based on the previously detected value of the charging current. The cell voltage is read (S24).

In the detection of the terminal voltage in S23, 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,
The average of the remaining values excluding the maximum value and the minimum value of these values is obtained, and this is taken as the effective terminal voltage. Also, one cell 1 of the nickel-cadmium storage battery 1 during charging
The cell voltage of a is 1.3 if the cell 1a is normal.
The higher the charging current in the range of V to 1.6 V, the higher the voltage. Therefore, in this embodiment, this one cell 1
It is obtained by approximating the cell voltage of a as the predicted cell voltage Vsel by a linear expression of the charging current I and calculating the expression Vsel = Vsel0 + kI. Here, Vsel0 is an initial value of a virtual predicted cell voltage when the charging current I is 0A. Also, k
Is a positive constant close to zero. Therefore, the relationship between the charging current and the predicted cell voltage is represented by a straight line rising to the right as shown in FIG. 4, and the predicted cell voltage gradually increases as the charging current increases. In the process of S24, the predicted cell voltage can also be calculated by calculating this formula Vsel = Vsel0 + kI based on the value of the charging current. However, since such a calculation puts an unnecessary burden on the microcomputer 2a, the ROM table method for reading the predicted cell voltage stored in the internal PROM in advance is used here. That is,
The charging currents are classified into appropriate ranges, the predicted cell voltages for the charging currents representing the respective ranges are calculated in advance, and the predicted cell voltages are written in the PROMs. It is designed so that only the predicted cell voltage of is read.

When the predicted cell voltage is read out as described above, this predicted cell voltage and the previously detected terminal voltage and E
The number of short-circuit cells is calculated from the number of rated cells stored in the EPROM 2e (S25), and the detected number of short-circuit cells is EEP.
The data is recorded in the ROM 2e (S26), and the shorted cell number detection process of S8 is completed.

In the process of S25, the predicted cell voltage is set to Vsel
, The terminal voltage is V and the number of rated cells is N, the number of short-circuit cells NS is expressed by the equation NS = INT ((N * Vsel-V) / Vsel
). That is, the partial expression (N × Vsel
−V) is a terminal voltage predicted by the product of the rated cell number N and the predicted cell voltage Vsel, and the predicted terminal voltage N × V
It is a value obtained by subtracting the actually detected terminal voltage V from sel, and the subtraction result should be approximately 0 V unless a cell short circuit occurs in each cell 1a. However, when a cell short circuit occurs, the internal resistance of the cell 1a in which the cell short circuit has occurred becomes approximately 0Ω, so this partial expression (N × Vsel −V) is a large voltage in proportion to the number of short circuit cells. To show the value. Therefore, if this partial expression (N × Vsel −V) is divided by the predicted cell voltage Vsel, the number of short-circuit cells, which is the number of cells 1a in which a cell short circuit occurs, can be obtained. However, the number of short-circuited cells obtained by this division usually has a fractional part below the decimal point, but cell short-circuiting is a phenomenon in which positive and negative electrode plates in the cell 1a are short-circuited, and the cell 1a is partially short-circuited. Since such a state cannot be considered, the number of short-circuit cells is generally an integer. Therefore, in the operation of S25, the INT function for converting the value of the argument into an integer is used to round down the fraction below the decimal point to obtain the integer number of short-circuit cells NS.

The number of short-circuited cells thus detected is S
It is recorded in the EEPROM 2e by the processing of 26. EE
The PROM 2e can store 16-bit data at each address (16-bit address), and in the recording area for the number of short-circuited cells, as shown in FIG. Each short-circuited cell number up to 12 cells is assigned, and a numerical value of the number of times of detection from 0 to 65535 can be recorded in each address. The numerical values of the addresses are all initialized to 0 when the storage battery device is shipped from the factory. And S
In the processing of 26, for example, if 2 cells are detected as the number of short-circuited cells, the EE corresponding to the number of short-circuited cells is 2.
The numerical value recorded in the address on the PROM 2e is incremented and updated. Therefore, the number of short-circuited cells detected here is recorded as a histogram-like table on the EEPROM 2e. In addition, when using the number of short-circuit cells recorded here for the judgment of battery abnormality etc., in order to be careful of detection, the one with the maximum number of cells detected three times or more is selected. Use the number of effective short-circuit cells. Therefore, for example, even if the number of short-circuit cells of 5 cells is detected and recorded only once or twice, if the maximum value of the number of short-circuit cells detected three times or more is 4, the effective number of short-circuit cells is Is 4 cells.

Once the charging is started, it is determined in the interrupt routine called thereafter that the charging state is set in the process of S2. Then, also in this case, subsequently, it is determined whether or not the value of the detected charging current is not less than the charging start current Imin (S9), and if it is determined that it is not less than the charging start current Imin, the above S
After executing the processes of 6 to S8, the interrupt routine is ended.

The charging operation is completed when the worker removes the storage battery device from the charger or when the charger automatically detects full charge by the -ΔV charging method or the like. When the charging is completed, the charging current is not supplied. Therefore, in the processing of S9 shown in FIG. 2 in the interrupt routine that is first called after that, it is determined that this charging current has become less than the charging start current Imin. The timer state is returned to the timer time T1 interval (S10), the charging state is released (S11), the value of the charging current in the RAM is updated to 0A (S12), and the interrupt routine is ended.
Then, this returns the control from the charging state to the first standby state. However, if the remaining capacity at the start of charging is R% or more of the rated battery capacity or if the charging is stopped before the integrated battery capacity reaches R% of the rated battery capacity, the above S8
The number of short-circuited cells is not actually detected by the processing of.

As described above, according to the short-circuit cell number detection device for the storage battery device of this embodiment, the number of short-circuit cells can be calculated from the difference between the terminal voltage predicted based on the predicted cell voltage and the terminal voltage actually detected. Since the change in the cell voltage according to the magnitude of the charging current is taken into consideration in the calculation, it becomes possible to accurately detect the number of short-circuited cells. Then, for example, when it is determined that the battery is abnormal when the number of short-circuit cells exceeds a predetermined number, the reliability of this determination can be improved.

When detecting the dry-up, in order to judge whether the cell voltage of each cell 1a of the nickel-cadmium storage battery 1 is abnormally high,
The terminal voltage is divided by the value obtained by subtracting the number of short-circuited cells from the number of rated cells. Therefore, by detecting the number of short-circuited cells accurately by the short-circuited cell number detection device of the present embodiment, the detection of dry-up can be made highly reliable.

Further, the integrated battery capacity stored in the RAM is set to a value of 0 mAm seconds immediately after the production of the storage battery device in which the nickel-cadmium storage battery 1 is in a completely discharged state, and thereafter, the above-mentioned charge capacity is set at the time of charging. In addition to the addition, by repeating the integration process of subtracting the discharge capacity calculated by the method not described in the present embodiment at the time of discharging, the battery capacity actually stored in the nickel-cadmium storage battery 1 at that time is represented at any time. Has become.
At this time, the nickel-cadmium battery 1 is discharged at the time of discharging.
When the cell voltage of each of the cells 1a becomes equal to or lower than the predetermined voltage, it is assumed that the cells have been completely discharged, and the cumulative battery capacity is reset to a value of 0 mAm second to prevent the accumulation of errors due to the accumulation. Therefore, also in this case, in order to compare the cell voltage with the predetermined voltage, it is necessary to divide the terminal voltage by a value obtained by subtracting the number of short-circuited cells from the number of rated cells. By detecting the number of short-circuited cells, the integrated battery capacity can be properly reset.

[0042]

As is apparent from the above description, according to the storage battery device with a short-circuit cell number detecting function of the present invention, the difference between the terminal voltage predicted based on the predicted cell voltage and the terminal voltage actually detected is obtained. When calculating the number of short-circuited cells, the change in cell voltage according to the magnitude of the charging current is taken into consideration, so that the number of short-circuited cells can be accurately detected.

[Brief description of drawings]

FIG. 1 is a flow chart showing an operation of a short-circuit cell number detection process shown in FIG. 2, showing an embodiment of the present invention.

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

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

FIG. 4 is a diagram showing an embodiment of the present invention and is a diagram showing a relationship between a charging current and a predicted cell voltage.

FIG. 5 shows an embodiment of the present invention, which is an EEP
It is a memory map of the recording area of the number of short-circuit cells in the ROM.

[Explanation of symbols]

 1 Nickel Cadmium Storage Battery 2 Microcomputer Substrate 2a Microcomputer 2b Terminal Voltage Input Circuit 2c Charging Current Input Circuit 2e EEPROM 4 Shunt Resistor

Claims (2)

[Claims] 1. A rechargeable storage battery comprising a plurality of cells, a charging current detection means for detecting a charging current flowing into the storage battery at the time of charging, a terminal voltage detection means for detecting a terminal voltage of the storage battery at the time of charging, and a charging operation. Based on the charging current detected by the current detecting means, a predicted cell voltage for calculating this voltage value as a predicted cell voltage for predicting a cell voltage per cell according to a predetermined conversion procedure for obtaining a higher voltage value as the charging current increases. Detecting the terminal voltage from the calculation means, the rated cell number recording means for recording the rated cell number of the storage battery, and the product of the predicted cell voltage calculated by the predicted cell voltage calculating means and the rated cell number recorded in the rated cell number recording means. Means for calculating the number of short-circuit cells by subtracting the terminal voltage detected by the means and further dividing the result of the subtraction by the predicted cell voltage. The number of short-circuit cell and feature detection function with a storage battery device. 2. The short-circuit cell number integer conversion means for rounding down the value after the decimal point of the number of short-circuit cells calculated by the short-circuit cell number calculation means to convert the short-circuit cell number into an integer, is provided. The storage battery device with the described short-circuit cell number detection function.