JP2000285968A - Storage battery over discharge preventing method, device, and monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an over discharge preventing device of a storage battery capable of surely preventing the over discharge of the storage battery. SOLUTION: An over discharge preventing device has a storage battery monitoring device 8 which monitors a state of a storage battery 1 used as a power source of a starter motor and outputs an alarm signal when it detects the fact that the remaining capacity of the storage battery 1 is smaller than the capacity necessary for driving a motor starting device at least once; and a switch means 2 which shuts off supply of power from the storage battery l to a load 3 with the alarm signal. The storage battery monitoring device 8 has a charge/discharge capacity computing means 9 for computing the discharge capacity and the charge capacity of the storage battery 1, a remaining capacity calculating means 10 for calculating the remaining capacity of the storage battery 1 based on the calculating result of the charge/discharge capacity calculating means 9, and a remaining capacity judging means 11 for outputting an alarm signal when the remaining capacity obtained by the remaining capacity calculating means 10 is smaller than a previously set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for preventing overdischarge of a storage battery and a monitoring device for the storage battery.

[0002]

2. Description of the Related Art In an automobile or the like, a starter motor is driven by using a storage battery as a power source when starting an engine. 2. Description of the Related Art Recently, electronic devices with large power consumption such as car navigation systems have been mounted on automobiles. Therefore, even when the engine is driven and the generator is generating power, the storage battery may be discharging. In such a case, if bad conditions overlap, even if the engine is stopped and then restarted, the remaining capacity of the storage battery is insufficient and the starter motor cannot be driven. Conventionally, normally-closed switch means for the protector is arranged between the storage battery and the load, and when the terminal voltage of the storage battery falls below a predetermined voltage level, the switch means is opened to forcibly discharge the storage battery. There has been proposed a technique for stopping the starter motor and ensuring restart of the starter motor.

[0003]

However, in the technology proposed in the prior art, since the determination is made based on the voltage level of the storage battery, the voltage level of the storage battery may be reduced due to a temporary increase in load or ambient temperature. When the voltage drops, the switch means may be erroneously opened, or on the contrary, the internal resistance increases due to deterioration and the voltage level rises, so that even if the capacity is actually lowered, Nevertheless, there is a problem that an overdischarge state occurs because the voltage level does not decrease and the engine cannot be restarted.

Conventionally, there has been no system capable of informing a driver of an automobile of a deterioration state of a storage battery used for such an application, a replacement time of the storage battery, a state of insufficient replenishment of an electrolyte, and the like with a certain degree of accuracy.

[0005] On the other hand, high temperature and deep discharge have become the main deterioration modes of automobile storage batteries. To cope with this, timely cooling (automation of cooling) and limitation of deep discharge (automatic disconnection of load) are effective. To achieve this, a system that can monitor the state of the storage battery as accurately as possible is required. There was, however, no such system in the past. In addition, the capacity of an automobile battery decreases due to self-discharge and a change in the specific gravity of the electrolyte. This indicates that grasping the history of the storage battery is useful for maintenance. Usually, to prevent the capacity from decreasing due to battery deterioration, specific gravity measurement of the electrolyte and maintenance by water replenishment are performed, and as a maintenance support, the water replenishment timing is displayed on the driver's seat and timely advice is given to determine the appropriate replacement time. It has been demanded.

In particular, when an engine is started by driving a starter motor using a storage battery deteriorated due to a shortage of liquid, an internal short circuit occurs inside the storage battery, which ignites hydrogen gas generated by electrolysis and causes a burst. Create a problem. In order to solve such problems, it was necessary to know the timing of water replenishment in a timely manner.

An object of the present invention is to provide a method and an apparatus for preventing overdischarge of a storage battery, which can surely prevent the storage battery from being overdischarged.

Another object of the present invention is to provide a storage battery monitoring device capable of knowing the usage history of the storage battery.

Still another object of the present invention is to provide a storage battery monitoring device capable of knowing when to replace a storage battery.

Another object of the present invention is to provide a storage battery monitoring device capable of knowing the time of replenishment of the electrolyte.

[0011]

SUMMARY OF THE INVENTION According to the present invention, the remaining capacity of a storage battery used as a power source for an electric starter such as a starter motor for starting an internal combustion engine is such that the electric starter is driven at least once. It is an object of the present invention to improve a method in which the supply of power from a storage battery to a load is stopped when the required capacity is less than the required capacity, thereby preventing the storage battery from being overdischarged.

In the present invention, the amount of discharge and the amount of charge of the storage battery are calculated, the remaining capacity of the storage battery is calculated from the calculation result, and when the remaining capacity obtained by the calculation becomes smaller than a predetermined value, Cut off the supply of power from the storage battery to the load. As described above, if the determination is made from the remaining capacity obtained based on the actual amount of discharge and the amount of charge, the storage battery can be overdischarged with higher accuracy than before without being greatly affected by the load state, the surrounding temperature environment, and the like. Can be prevented.

When the storage battery deteriorates, the capacity in a fully charged state decreases. Therefore, in the present invention, when the number of charge / discharge of the storage battery reaches a predetermined number, the internal resistance of the storage battery in a fully charged state is measured, and the deterioration state of the storage battery is determined based on the internal resistance. The capacity of the storage battery in the fully charged state is corrected based on the result. In this way, the storage battery is not greatly affected by the deterioration,
It is possible to prevent the storage battery from being over-discharged with higher accuracy than before. When measuring the internal resistance, it is desirable to cut off the electrical connection between the storage battery and the load. In this way, when measuring the internal resistance, the influence of the load can be cut off, so that the measurement accuracy of the internal resistance increases, and as a result, the accuracy of determining the state of the storage battery increases.

An overdischarge prevention device for a storage battery to be improved by the present invention monitors the state of a storage battery used as a power source of an electric starter such as a starter motor for starting an internal combustion engine, and detects the remaining capacity of the storage battery. A storage battery monitoring device is provided that outputs a warning signal when it detects that the capacity of the electric starting device has become smaller than a capacity required for driving the electric starting device at least once or more. The storage battery monitoring device further includes switch means for interrupting supply of power from the storage battery to the load when the storage battery monitoring device outputs an alarm signal. A storage battery monitoring device used in the present invention includes a charge / discharge amount calculating unit that calculates a discharge amount and a charge amount of the storage battery; a remaining capacity calculation unit that calculates a remaining capacity of the storage battery from a calculation result of the charge / discharge amount calculation unit; And a remaining capacity determining means for outputting an alarm signal when the remaining capacity obtained by the capacity calculating means becomes smaller than a predetermined value. With such a configuration, it is possible to easily and reliably prevent the storage battery from being in the overdischarge state with higher accuracy than before, without being greatly affected by the load state, the surrounding temperature environment, and the like.

The storage battery monitoring device has an internal resistance measuring means for measuring the internal resistance of the storage battery in a fully charged state when the number of times of charging and discharging of the storage battery reaches a predetermined number, and the internal resistance measuring means for measuring the internal resistance. Deterioration state determination means for determining the deterioration state of the storage battery based on the internal resistance is further provided, and the remaining capacity calculation means corrects the capacity of the storage battery in the fully charged state based on the determination result of the deterioration state determination means, and The capacity may be calculated. In this case, a decrease in the full charge amount due to the deterioration of the storage battery can be considered, so that the determination accuracy is increased. In this case, it is preferable that the storage battery monitoring device is configured to output an alarm signal to switch off the switch unit when the internal resistance measuring unit measures the internal resistance.

The storage battery monitoring apparatus according to the present invention further comprises a use condition detecting means for detecting a use condition of the battery such as a discharge electricity amount and a charge electricity amount of the storage battery, and a use condition for storing a detection result of the use condition detection means as a history. History storage means. By using such a monitoring device, it is possible to know the past history of the usage status of the storage battery, and as a result, it is possible to provide the user who uses the storage battery with data for examining the usage mode of the storage battery. Based on the history, it is possible to generate an alarm for notifying the end of the life of the storage battery, an alarm for notifying that the electrolyte is low, an alarm for notifying that the load is too large, and the like, so that the user can manage the storage battery. For example, a storage battery replacement time determination unit that determines a replacement time of the storage battery from the history stored in the usage status storage unit and outputs a storage battery replacement warning signal when it is determined that the replacement time has been reached may be further provided.

The present invention also provides a storage battery monitoring device that requires replenishment of the electrolyte. This monitoring device includes a water level detecting means for detecting a water level of the electrolyte of the storage battery, and a water level determining means for outputting an electrolyte replenishment alarm signal when the water level detected by the water level detecting means falls below a predetermined level. With such a configuration, the decrease in the electrolyte can be automatically detected.

The storage battery monitoring device includes means for measuring the voltage, current, temperature, liquid level, and time of the storage battery, means for instantaneously calculating the usable amount, and a corresponding current breaker, cooling device, display device, Combined with an external memory or the like, it may be constituted by means for automatically controlling the remaining amount, cooling and display, and means for starting monitoring from the first discharge after mounting on the storage battery and recording the usage history of the storage battery. For accurate power supply management, data processing may be performed using both the current integration method and the internal resistance detection method, and the usable amount of the storage battery may be sequentially corrected to calculate the remaining capacity of the storage battery. Furthermore, the storage battery monitoring device measures the internal resistance to estimate the storage battery usable amount in order to take measures against cumulative errors due to frequent charging and discharging of gasoline engine vehicles,
A function of comparing the integrated value with the actually measured estimated value and appropriately resetting the full charge capacity to zero may be provided. In order to output a display output signal, a serial transmission device may be attached so as to be able to display on an existing in-vehicle meter panel, NAVI screen, or the like in accordance with the CAN protocol.

Also, in order to monitor the status of the lead-acid battery for the vehicle and to drive protection measures for the purpose of assuring the starter function of the vehicle and assisting maintenance, a circuit incorporating a power control IC in the battery, a current breaker, a thermometer, and an electronic device. A water level gauge may be installed to perform accurate state monitoring, battery cooling automation, battery protection such as automatic disconnection of load, etc., and output of signals such as remaining capacity display, water replacement timing instruction, battery replacement advice, etc. .

The control board comprises a measuring section and a signal operation circuit section. The measuring section has an analog circuit section and a digital circuit section, and the analog circuit section has internal resistance detecting means. The water level gauge may include an accurate water level determination unit that responds to fluctuations in the water level due to vibration caused by measuring and determining a number of times. Further, a function of counting the time from the start of use to grasp the use history of the battery and enabling detailed maintenance may be included.

[0021] Further, by the instruction of the host computer utilizing the battery signal, the engine is frequently switched to automatically stop the idling of the vehicle, and the light automatically flashes (tunnel / intersection), cooling / heating reservation, warm-up operation, theft prevention, standby sleep. And so on. A communication function that can transmit and receive battery information that shares a signal with an automotive LAN that can manage the power supply and control the actuator drive collectively that supports this may be provided.

Data processing is performed using both the current integration method and the internal resistance detection method, and when the remaining battery capacity is calculated by successively correcting the usable amount of the storage battery, it corresponds to the accumulated error due to frequent charging and discharging of the gasoline engine vehicle. The number of times of charging and discharging is counted, and every time the set number of times is exceeded, the integrated value is compared with the actually measured estimated value (discharge rate is estimated from the internal resistivity) and the full charge capacity is automatically changed (reset-zero adjustment). May be performed.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a storage battery over-discharge prevention apparatus according to an embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of an example of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a storage battery used as a power supply of an electric starter such as a starter motor for starting an engine of an automobile, that is, an internal combustion engine. In this example, a liquid lead storage battery is used as the storage battery 1. Reference numeral 2 denotes switch means for cutting off the supply of power from the storage battery 1 to the load 3 including the starter motor. The switch means 2 is a normally-closed electromagnetic switch, which is opened when an alarm signal is output from the storage battery monitoring device 8 described later, and resets (the key switch is opened and the key switch is closed again). The open state is maintained until the operation is performed. A device called a protector provided with this type of switch means is disclosed in Japanese Patent Publication No. Hei 5-6077. The relationship between the load mounted on the vehicle, the storage battery 1, the switch means 2, and each load is as shown in the circuit diagram of FIG. In FIG. 2, reference numeral 31 denotes a key switch manually operated by a driver, and reference numeral 32 denotes a starter motor connected to the storage battery 1 through one contact of the key switch 31 to start the engine E. Another contact of the key switch 31 includes an ignition device 33,
A load A such as an air conditioner, audio, and NAVI is connected to a load B such as a light, a radio, and an anti-theft device. Reference numeral 34 denotes a magnet generator that generates AC power for charging the storage battery 1, and reference numeral 35 denotes a rectifier circuit that converts AC power of the magnet generator 34 into DC power and rectifies the DC power. The storage battery 1 is floatingly charged by the DC output of the rectifier circuit 35 when the switch means 2 is in the closed state.

The storage battery monitoring device 8 of this embodiment monitors the state of the storage battery 1 and issues an alarm when it detects that the remaining capacity of the storage battery 1 has become smaller than the capacity required for driving the starter motor at least once. A function of outputting a signal, a function of changing a reference charge amount (a reference charge amount for calculation) in a fully charged state of the storage battery 1 according to a change (deterioration state) of the internal resistance of the storage battery 1, and use of the storage battery A function of storing a history of the situation, determining a replacement time of the storage battery 1 based on the stored history, and detecting a water level of the electrolyte of the storage battery 1 and outputting an electrolyte replenishment alarm signal when the water level falls below a predetermined level. It has a function to generate. Therefore, in order to detect the use condition of the storage battery 1 required for exerting these functions, in this example, a voltage detecting means 4, a current detecting means 5, a temperature detecting means 6, and a water level detecting means 7 are provided. ing. The voltage detecting means 4 is configured by, for example, a voltage measuring resistor circuit connected between output terminals of the storage battery, and measures a voltage between terminals of the storage battery 1. The current detecting means 5 includes a current transformer, and measures a discharge current output from the storage battery 1 and a charging current for charging the storage battery. The temperature detecting means 6 is joined to the outside of the battery case of the storage battery 1 and indirectly measures the internal temperature of the storage battery 1. As the temperature detection means 5, a thermistor or the like can be used. As the water level detecting means 7, for example, a means configured to convert the output of a float type water level meter into an electric signal can be used.
Voltage detecting means 4, current detecting means 5, temperature detecting means 6
Since the output of the water level detection means 7 is an analog signal, the analog signal is converted into a digital signal using an A / D converter in order to perform signal processing using a microcomputer. In this example, the output of each detecting means is A /
D conversion.

The storage battery monitoring device 8 of this embodiment calculates the amount of discharge and charge of the storage battery 1 and calculates the remaining capacity of the storage battery 1 from the calculation result of the calculation of the amount of charge and discharge. Remaining capacity calculating means 10 and remaining capacity calculating means 1
And a remaining capacity determining means for outputting an alarm signal when the remaining capacity determined by 0 is smaller than a predetermined value. In this example, when the number of times of charging and discharging the storage battery 1 reaches a predetermined number (for example, 1000 times),
It further includes an internal resistance measuring means 12 for measuring the internal resistance of the storage battery 1 in a fully charged state, and a deterioration state determining means 13 for determining the deterioration state of the storage battery 1 based on the internal resistance measured by the internal resistance measuring means 12. are doing.

The charge / discharge amount calculating means 9 calculates the amount of electricity supplied to the load from the storage battery 1 (discharged electricity) and the amount of electricity for charging the storage battery 1 (charged electricity) based on the output of the current detection means 5. Are obtained by calculation. The charge / discharge amount calculating means 9
Performs a temperature correction based on the output of the temperature detecting means 6.

The remaining capacity judging means 10 determines whether the storage battery 1 is fully charged based on the judgment result of the deterioration state judging means 13.
And the remaining capacity of the storage battery 1 is calculated. FIG. 3 is a diagram illustrating an example of the relationship between the internal resistivity and the discharge rate of the storage battery. In this figure, the internal resistivity indicates that the discharge rate is 0.
Batteries, ie new batteries (batteries that have not deteriorated)
Is the reference internal resistance [Ro], and the internal resistance [Rt] measured when the switch means 2 is open.
Is divided by the reference internal resistance. And the discharge rate [α]
Means that the discharge amount [Ah] is the maximum usable capacity [Ah] of the storage battery.
F]. What is the maximum usable capacity of a storage battery?
From the full charge capacity [AhF] to the minimum remaining battery capacity [Ah]
Is the value obtained by subtracting. As the deterioration of the storage battery 1 progresses, the internal resistance increases and the maximum usable capacity of the storage battery decreases, so that the discharge amount and the value of the maximum usable capacity of the storage battery approach each other. As a result, the discharge rate increases. That is, an increase in the internal resistivity and the discharge rate means that the storage battery is in a deteriorated state. Also, by knowing the internal resistance, it is possible to know the fully charged amount of electricity (actually, the maximum usable capacity of the storage battery) at the time of full charge when the deterioration has progressed.

Then, the deterioration state judging means 13 calculates the internal resistivity based on the internal resistance measured by the internal resistance measuring means 12, and based on the internal resistivity, the internal resistivity-discharge as shown in FIG. The deterioration state at that time is determined from the rate-related data, and data (aged deterioration amount) for correcting the capacity of the storage battery at the time of full charge at that time is output to the remaining capacity calculation means 9. When the internal resistance measuring means 12 operates, the switch means 2 is in an open state. This is because the measurement accuracy is reduced if the impedance of the load is included in the measurement of the internal resistance. The internal resistance measuring means 12
The configuration and operation of the deterioration state determining means 13 will be described in detail in the description of a specific example later.

The remaining capacity calculation means 10 uses the full charge capacity of the storage battery 1 in the fully charged state corrected in consideration of the deterioration state as a reference capacity to add or subtract the calculation result of the charge / discharge amount calculation means 9 to or from this reference capacity. To calculate the remaining capacity of the storage battery. The remaining capacity determination means 11 outputs an alarm signal when the remaining capacity calculated by the remaining capacity calculation means 10 becomes smaller than a predetermined value. Here, the “predetermined value” for the remaining capacity is a value equal to or more than the capacity required to drive the starter motor at least once or more.
From the viewpoint of safety, it is preferable to set the capacity enough to drive the starter motor to a predetermined value of the remaining capacity for a few times.

When the remaining capacity judging means 11 outputs an alarm signal to the switch means 2, the switch means 2 is opened, the supply of power from the storage battery 1 to the load is stopped, and overdischarge is prevented, and the engine is stopped. As a result, power is secured for restarting the vehicle. If the capacity of the load when the switch means 2 is opened is large, the output voltage of the load generating coil of the generator driven by the engine decreases, and a load requiring a large amount of electric power, such as an air conditioner or an audio device, is reduced. Stop operation. When the engine is stopped and the key switch 31 is turned on again, the switch unit 2 is reset and closed. When the engine is started, the switch means 2
In order to prevent the remaining capacity from being opened, for example, during a period in which the key switch 31 is activating the starter motor, a predetermined time after the switch means 2 is closed so that the remaining capacity determination means 11 does not perform the determination operation. The remaining capacity determination means 11 may be configured so that the remaining capacity determination means 11 does not operate until the time elapses. Specifically, a timer that starts a count operation after the switch unit 2 is closed may be used.

In this example, voltage detecting means 4, current detecting means 5, temperature detecting means 6, water level detecting means 7, charge / discharge calculating means 9, remaining capacity determining means 11, deterioration state determining means 13,
The water level judging means 14, which will be described later, constitutes a use state detecting means. Then, the outputs of these use state detection means are stored in the use state history storage means 15. For an output with a large amount of data, the data is sampled and stored. Further, in this example, the replacement time of the storage battery 1 is determined from the history stored in the usage history storage unit 15,
It further includes a storage battery replacement timing determination unit 16 that outputs a storage battery replacement warning signal when it is determined that the replacement timing has been reached. The determination of the replacement time includes, for example, the internal resistivity and the discharge rate,
The temperature rise rate and the like are compared with a reference value, and the determination is performed based on whether any one of them exceeds the reference value.

The water level detecting means 7 detects the water level of the electrolyte of the storage battery and outputs it as an electric signal. The water level detecting means 7 may be attached to all cells, but one water level is selected for one cell selected from among a plurality of cells while taking care to represent the water level of each cell even when traveling on a slope. The detecting means 7 may be provided. Since the automobile generates large vibrations while traveling, the vibration may cause a temporary drop in the water level. Therefore, the water level determination means 14
Outputs an electrolyte replenishment alarm signal when the water level detected by the water level detection means 7 repeatedly falls below a predetermined level.
Specifically, measurement is performed for 5 seconds, and an electrolyte replenishment alarm signal is output when the total time when the water level falls below a predetermined level becomes 2 seconds or less. The switch means 2 may be opened when the output of the temperature detecting means 6 becomes equal to or higher than a predetermined temperature or when an electrolyte replenishment alarm signal is output. By doing so, it is possible to prevent the storage battery 1 from going into a thermal runaway state.

FIG. 4A is an external perspective view of a case where the storage battery monitoring device 8 incorporating the switch means 2 of FIG. 1 is formed as a unit. Reference numeral 81 denotes a communication connector. FIG. 4B is a perspective view showing a state where the storage battery monitoring device 8 is mounted on a storage battery.

FIG. 5 is a circuit diagram showing a hardware configuration of a main part when the configuration of FIG. 1 is realized using a microcomputer. Note that members constituting the components shown in FIG. 1 are denoted by the same reference numerals as those denoted in FIG. 12
A is a forced discharge circuit constituting a part of the internal resistance measuring means 12 of FIG. The forced discharge circuit 12A includes a discharge resistor R, a switch SW, an amplifier OP1,
a. When measuring the internal resistance,
The switch SW is turned on to perform forced discharge, and the voltage change at this time is output from the differentiating circuit 12a. The internal resistance measuring means 12 measures the internal resistance using the voltage change by a known method. The measurement is performed by calculation by the CPU. 17 is a serial transmission device,
The serial transmission device 17 checks the information signal of the storage battery and transmits / receives the information signal to / from the on-board host computer. The serial transmission device 17 transmits and receives a storage battery information signal connectable to a USB for automobiles conforming to the CAN protocol, and is a signal compatible with a display device sufficient to update and display at least the battery capacity and the battery replacement time.

The storage battery monitoring device 8 includes a CPU 81 and an RO
M82 and 83, RAM 84, A / D converter 85
, W / R 86, RTC 87, and SIO 88. The serial transmission device 17 includes a CPU 171
ROMs 172 and 173, RAM 174, SI
O175 to 177. The outputs of each forced discharge circuit 12A, voltage detecting means 4, current detecting means 5, temperature detecting means 6, and water level detecting means 7 are output from insulating amplifiers OP1 to OP1.
After being amplified by OP5, it is converted into a digital signal by the A / D converter 85. In the storage battery monitoring device 8, A /
The CPU 81 performs a sequential operation based on the output of the D converter 85, and outputs serial data from the serial transmission device 17 every second.

The CPU 81 calculates the amount of discharge and the amount of charge of the storage battery 1 and calculates the remaining capacity of the storage battery 1 from the calculation result. When the remaining capacity obtained by the calculation becomes smaller than a predetermined value, An alarm signal for opening the switch means 2 of FIG. 1 is generated. Further, in order to reflect the deterioration state of the storage battery 1, the CPU 81 measures the internal resistance of the storage battery in the fully charged state when the number of times of charging and discharging of the storage battery 1 reaches a predetermined number, and based on the internal resistance, The deterioration state of the storage battery is determined, and the capacity of the storage battery in the fully charged state is corrected based on the determination result. Therefore, an operation for measuring the internal resistance of the storage battery 1 is performed based on the voltage change obtained from the differentiation circuit 12a of the forced discharge circuit 12A, and the result is reflected in the calculation of the battery capacity. The calculation program is stored in the ROM 82. Various data (ex. Storage battery model, temperature correction) used for the calculation is R
Store in OM83. Each input data is stored in the RAM 84
To be stored.

The input line 17B of the serial transmission device 17
Can be connected to a keyboard (possible with a personal computer), so that various setting data used for calculation can be externally updated. Line 17A is
A communication cable for connection with the host OS of the automobile is connected. The host OS of the vehicle is assumed to be an existing general-purpose OS.

Next, the basic operation will be described. Before describing the basic operation, terms used in the following description are defined as follows.

(1) Remaining capacity [Ah]: Remaining capacity of the storage battery.

(2) Full charge capacity [AhF]: The full capacity when the storage battery is fully charged.

(3) Minimum storage battery remaining capacity [Ah]: lower limit capacity that must always be kept, usually 20% of rated capacity
And

(4) Maximum usable capacity of the storage battery [Ah
F]: A value obtained by subtracting the minimum remaining battery capacity from the full charge [AhF].

(5) Storage battery usable capacity [Ah]: A value obtained by subtracting the minimum storage battery remaining capacity [Ah] from the remaining capacity [Ah].

(6) Full charge: When the storage battery is charged, it is determined that the battery is fully charged when the terminal voltage of the storage battery is 14.5 V or more, and the charging current is less than or equal to A recommended for the corresponding product type of the battery manufacturer (ex. 0.05 A). ).

(7) During operation: A state in which a current of 0.5 A or more flows from the storage battery.

(8) During stop: the battery current is 0 to 0.5 A
The state of less than or equal to 2 seconds or more.

(9) Reference internal resistance [R0]: Refers to the internal resistance measured immediately after the completion of full charge.

(10) Internal resistivity [Rr]: A value obtained by dividing the internal resistance [Rt] measured during stoppage by the reference internal resistance [R0].

(11) Discharge rate [α]: A value obtained by dividing the discharge amount [Ah] by the maximum usable capacity [AhF] of the storage battery.

(12) Self-discharge amount: ignition key o
It refers to the discharge amount discharged by natural discharge at ff. This self-discharge amount is a set value that can be arbitrarily changed from the terminal. Normally, the self-discharge amount specified for the corresponding product type of the battery manufacturer [ex. (0.4-1.0 / 100)
x rated capacity Ah / day].

(13) Aging deterioration amount [kd]: The amount by which the full charge capacity decreases with repeated charging and discharging of the storage battery. This aging deterioration amount is a set value that can be arbitrarily changed from the terminal. (14) Cumulative error [δ]: Accumulated [微小 ± Ah (t)] of minute errors in current measurement generated at every frequent charge and discharge.

The basic operation is as follows.

(1) After the first full charge of the storage battery 1 is completed, the monitoring device 8 is started by the first discharge when the ignition key switch is turned on, and the subsequent history is recorded.

(2) When the ignition key is turned off after confirming the start of monitoring and the stop of the storage battery is confirmed, the first internal resistance measurement is performed and the battery capacity data is transmitted.

(3) Thereafter, the current value is monitored, the temperature is corrected with reference to the ROM data, and the remaining battery capacity is updated every second when the ignition key is turned on. Monitoring of the current value is performed by checking whether the storage battery discharges to the preset required protection capacity,
Alternatively, until the charge amount exceeds the discharge amount and the full charge condition is satisfied, the current value is finely integrated to continuously calculate the remaining battery capacity.

(4) Further, the number of times the current flow reverses during this period is counted. When the number of times that the current flow of the storage battery reverses (the number of times of charging and discharging) exceeds a set number of times (for example, 1000 times), the battery is fully charged immediately, and then the cutoff switch means 2
When it is confirmed that the storage battery has stopped, the instantaneous current is forced to flow through the resistance load R in the monitoring device, and the internal resistance is measured.
After confirming the full charge, the battery capacity is reset in comparison with the reference capacity to update the full charge capacity.

(5) When the ignition key is turned off, no current flows through the storage battery 1, and when the vehicle is parked for a long time, the amount of self-discharge is calculated to reduce the battery capacity.

The self-discharge coefficient uses the value input from the terminal. When the full charge capacity is updated, the total of the discharge amount is newly started from that point.

(6) When aging has occurred, the following is performed. First, an instantaneous current is forced to flow through the resistance load R in the measurement unit to measure the internal resistance. The internal resistance is measured by comparing the internal resistance with the ROM data to make a full charge for reset from the estimated full charge capacity and measuring the internal resistance.
The difference in the full charge capacity estimated from the data is calculated as the aging deterioration amount [kd
(T)], and the new measured capacity value is set as a new full charge amount AhF (t). When the full charge capacity is updated, the total of the discharge amount is newly started from that point.

In order to perform the above operation, the following is specifically performed. First, the lead-acid battery has a rated capacity of 80%.
% Or more, the life is significantly deteriorated.
The 0% discharge point (the above-mentioned point storage battery usable capacity) is accurately detected, and the remaining capacity display of the meter is set to 0 at that point.
To The meter may be installed in the driver's seat of the car,
It may be mounted on a unit of the monitoring device.

In a lead-acid battery, the electric energy (usable capacity of the storage battery) that can be taken out varies greatly depending on the use conditions (battery temperature, discharge current, internal electrolyte volume, etc.). It is necessary to go. Therefore, the current integration method and the internal resistance method are used together to calculate the storage battery remaining capacity, and the calculation accuracy of the storage battery remaining capacity is improved. That is, one of the usable capacity of the storage battery
Up to the range of 00 to 30%, the discharge current of the storage battery is finely integrated and subtracted from the storage battery capacity (current integration method).
In this method, the storage battery internal resistance is measured in the range of 30 to 0% (internal resistance detection method), and the remaining capacity obtained by the current integration method is corrected and displayed.

Further, for a storage battery corresponding to frequent charging and discharging of a gasoline engine vehicle, it is necessary to appropriately cancel the accumulated error generated during this period. Therefore, the number of times that the direction of the current reverses as viewed from the storage battery (the number of times of charge / discharge) is counted, and the storage battery is fully charged, the internal resistance is measured, and the estimated value is compared with the ROM data at every predetermined number of times. The reset is performed by updating the full charge capacity in comparison with the meter capacity.

When the ignition key switch is turned on after the completion of the first full charge, the discharge voltage is lower than the set voltage when the storage battery is discharged for the first time and compared with a preset voltage value, for example, 11 V. Circuit means for detecting the time is separately provided inside the storage battery monitoring device 8. Therefore, until the battery is installed in the car,
Since the battery voltage is almost 12 V or more, the monitoring device does not start monitoring the battery capacity. However, when the storage battery is discharged with a large current even though it is instantaneous due to the start of the engine or the use of a lamp, an AV device, a wiper, etc., the battery voltage drops sharply and falls below the set voltage of 11 V. The circuit means detects. Then, the monitoring of the battery is started from the point in time when the voltage at the time of discharging falls below the set voltage value. This circuit means prevents the above-mentioned command from being repeated each time the battery is started by turning off the switch once monitoring is started. In addition, the history data of the storage battery is communicated and recorded in an external log file at a fixed amount through a terminal for the purpose of assisting the storage capacity of the present apparatus.

Next, a specific example in the case where the storage capacity of the storage battery is calculated by the storage battery monitoring device will be described. (1) At the time of installation (including at the time of replacement of the main storage battery) At the time of installation, the storage battery of the vehicle must be fully charged. At this time, the full charge capacity and the remaining capacity are set to the rated capacity (Ah) regardless of the degree of deterioration of the storage battery, and the self-discharge amount and the aged deterioration amount are set to 0.

(2) During operation and stoppage The remaining capacity is calculated by the current integration method. The calculation formula is shown in the following formula [1].

Ah (t) = Ah (0) −Σ (kd · id · Δt) + Σ (kr · ir · Δt) [1] where Ah (t): remaining capacity at time t [ Ah] Ah (0): Remaining capacity at time 0 [Ah] Σ (kd · id · △ t): Electricity used from time 0 to t Σ (kr · ir · △ t): Time 0 to t Kd: Discharge current value id: Discharge current coefficient ir: Charge current value kr: Charge current coefficient: Can be changed arbitrarily The number of times of sampling of the current value is 5000 samplings per second, and the integral value of the 5000 samplings Is a current value every second.

I. e. I = Σi · △ t I: Current value [A] per second i: Instantaneous value of current [A / S] Δt: Sampling interval (0.2 ms) (3) Correction of full charge capacity and remaining capacity Based on the internal resistivity [Rr] obtained by discharging, the remaining capacity [Ah] and the full charge capacity [AhF] at that time are corrected by a method of estimating the full charge amount and the remaining capacity from the internal resistance described later.

(4) The charge is basically calculated by the current integration method. Formula [2] shows a calculation formula of the remaining capacity [Ah] during charging.

Ah (t) = Ah (t1) −Σ (kc · ic · Δt) (2) where Ah (t): remaining capacity at time t [Ah] Ah (t1): time t1残存 (kc · ic · △ t): Electricity charged from time t1 to t ic: Charging current value kc: Charging current coefficient: arbitrarily changeable If the full charge capacity of the meter is exceeded at that time, the remaining capacity shall be the same as the full charge capacity. Also, the full charge condition was satisfied at the time of charging,
If the remaining capacity does not reach the full charge capacity of the meter, the remaining capacity at that time is regarded as the full charge capacity, and it is assumed that the meter is fully charged. If the full charge condition is not satisfied at the time of charging and the remaining capacity does not reach the full charge capacity of the meter at that time, the full charge capacity is not changed and the remaining capacity is the current capacity.

The self-discharge is processed as follows.
The time during which the ignition key switch was left in the off state was measured in minutes, and the amount of self-discharge per minute [ex. (0.4 to 1.0 / 100) x capacity / 24 x 60 A min. ] Is subtracted from the remaining capacity the next time the ignition key is turned on. However, it is assumed that there is no self-discharge during charging, and the self-discharge is not counted even if the ignition key switch is off.

The aging is handled as follows. Measured after full charge for resetting, the difference between the latest battery capacity estimated by comparing with the ROM data and the battery capacity derived from the internal resistivity measured at startup is the aging deterioration amount [k
d (t)], and the latest estimated battery capacity is taken as the new full charge AhF (t). The latest internal resistivity can be corrected from the terminal.

When the full charge capacity is updated, the total discharge amount is newly started from that point. The updated full charge capacity AhF (t) can be calculated by the following equation [3].

AhF (t) = AhF (t−1) −kd [3] In the above equation, AhF (t−1) is the full charge capacity held inside the meter before, and kd is the aging It is the amount of deterioration.

The storage battery replacement time alarm is generated as follows. The storage battery replacement timing alarm is transmitted when the state where the full charge capacity is equal to or less than half of the rated capacity continues for 10 times or more due to aged deterioration or the like and becomes equal to or less than the preset threshold value of the storage battery.

Table 1 shows each coefficient used in the algorithm of the software used for the above-mentioned various operations. The discharge characteristics of the storage battery on which this algorithm is based are as shown in FIG.

[0076]

[Table 1] Next, monitoring of the liquid level will be described.

An electronic liquid level gauge is used as the water level detecting means 7. The electronic liquid level meter measures the number of times of measurement set in advance using a sensor attached to an opposing position where the liquid level is balanced, and determines the liquid position based on the total number of exposures. The judgment is made as follows.

Σe (t) · S> K exposure Σe (t) · S ≦ K Number of sensors in liquid S Measurement time t Measurement times NT Exposure times e Total exposure times Σe (t) Judgment times K Next, forced discharge A method for estimating the full charge capacity and the remaining capacity of the storage battery from the measurement of the internal resistance will be described. The procedure is described below in (1) to (5).

(1) Immediately after the completion of full charge, instantaneous forced discharge is
0 times, and the average value of the internal resistance is set to the reference internal resistance value R0.
And (The time required for 10 instantaneous forced discharges is 200 m
s) (2) After confirming no-load stop (when the battery current is within 0 to 0.5 A for 2 seconds or more), instantaneous forced discharge is performed only once, with 10 times as one sample. Determine the internal resistance of the storage battery.

(3) At this time, when the internal resistivity [Rr] is 1.
When it becomes 2% or more, the ratio α of the discharge amount up to that point with respect to the internal resistivity and the full charge capacity determined in advance by experiments.
The discharge rate αt is obtained with reference to a discharge rate table (FIG. 3) showing the relationship (hereinafter referred to as a discharge rate). When the internal resistivity [Rr] is 1.2% or less, the full charge capacity AhF
(T) The remaining capacity Ah (t) is not corrected each time, but the remaining capacity is corrected separately from the full charge capacity reset in response to the internal resistance measurement performed at regular intervals.

(4) Based on the discharge rate αt, the full charge capacity and the remaining capacity are corrected as shown in (a) and (b) below.

(A) Method of Estimating Full Charge Capacity Assuming that the full charge capacity is AhF (t), the calculation formula is shown below.

AhF (t) = Σid (t) / αt Here, Σid (t): discharge amount discharged up to that time (time t) αt: discharge rate.

(B) Estimation method of remaining capacity
The calculation formula is shown below as (t).

Ah (t) = (full charge capacity) − (discharge amount discharged up to that time) = AhF (t) −Σid (t) = (1 / αt) Σid (t) −Σid (t) = ｛ (1-αt) / αt｝ Σid (t) (c) Reset-zero adjustment When the storage battery satisfies the full charge condition, the internal resistance is measured and the meter is reset. When the vehicle is stopped, the meter reset display signal requests the driver for permission by an idling continuation request signal, continues idling until the vehicle is fully charged, satisfies the full charge condition, measures the internal resistance, and resets the meter.

According to the above-described embodiment, accurate power management is performed while allowing the IC incorporated in the storage battery monitoring device 8 and the on-board computer to interact, and the temperature and overdischarge can be monitored.
Automatic cooling is possible, and the starter motor can be reliably started by protecting the battery from overload with the protector. Further, by displaying the water refill timing on the driver's seat and keeping the lower limit line, an accidental explosion can be prevented. Also, by recording the history of the storage battery,
Reliable battery maintenance can be performed easily,
Judgment and advice on appropriate replacement time can be made. As described above, the remaining capacity can be displayed with high accuracy even during traveling, so that the driver can travel with peace of mind, can operate up to the full battery capacity, and improve utilization efficiency. In addition, by adopting a signal processing method common to that of the existing automotive LAN, it becomes possible to drive various actuators in accordance with instructions from the on-board computer and perform collective control. For example,
Anti-theft, idling stop of A / T car (frequent switching of engine), automatic blinking of lights (tunnel / intersection), air-conditioning reservation, warm-up operation, standby power consumption countermeasures (ex. Sleep function) are possible.

Further, the output of the water level detecting means 7 can display the water level status and the alarm on the driver's seat display device such as a vehicle-mounted meter or NAVI. The output signal for display is C
Compliant with AN protocol, existing onboard meter panel and NA
It can be displayed on a VI screen or the like.

Further, according to the output of the temperature detecting means 6, the battery 1
May be driven by an automatic cooling device (fan or water cooling) attached to the device. In addition, frequent switching of the engine and automatic blinking of the light may be performed in accordance with the vehicle speed signal and the optical sensor installed in the vehicle compartment.

The monitoring device 8 operates after the storage battery 1 is mounted on the vehicle.
Start monitoring of the timer is started at the first discharge, and the subsequent history is recorded. The power management is performed by measuring the current, voltage, temperature, and internal resistance of the battery (calculated from the amount of voltage change and the amount of current change during forced discharge) and processing digital data to calculate the capacity of the battery.

[0090]

According to the present invention, the amount of discharge and the amount of charge of the storage battery are calculated, the remaining capacity of the storage battery is calculated from the calculation result, and the remaining capacity obtained by the calculation is smaller than a predetermined value. Sometimes, the supply of power from the storage battery to a load other than the electric starter is shut off, so that the storage battery is overdischarged with higher accuracy than before without being greatly affected by the load state, the surrounding temperature environment, and the like. Can be prevented. In addition, when the state of deterioration of the storage battery is determined based on the internal resistance of the storage battery, and the capacity of the storage battery in the fully charged state is corrected based on the result, the storage battery is not affected by the deterioration of the storage battery greatly and has a higher accuracy than before. Can be prevented from being over-discharged.

If the electrical connection between the storage battery and the load is cut off when measuring the internal resistance, the influence of the load can be cut off when measuring the internal resistance. As a result, the accuracy of determining the state of the storage battery is increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an example of an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a load circuit of a storage battery.

FIG. 3 is a diagram showing an example of a relationship between an internal resistivity and a discharge rate of a storage battery.

FIG. 4A is an external perspective view in the case where a storage battery monitoring device incorporating the switch unit of FIG. 1 is formed as a unit;
FIG. 2B is a perspective view showing a state where the storage battery monitoring device of FIG. 1A is mounted on a storage battery.

FIG. 5 is a circuit diagram showing a hardware configuration of a main part when the configuration of FIG. 1 is realized using a microcomputer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage battery 2 Switching means 3 Load 4 Voltage detection means 5 Current detection means 6 Temperature detection means 7 Water level detection means 8 Storage battery monitoring device 9 Charge / discharge amount calculation means 10 Remaining capacity judgment means 11 Remaining capacity judgment means 12 Internal resistance measurement means 13 Deterioration State determination means 14 Water level determination means 15 Usage history storage means 16 Storage battery replacement time determination means 17 Serial transmission device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 10/48 H01M 10/48 P H02J 7/00 H02J 7/00 M // B60R 16/02 670 B60R 16 / 02 670P (72) Inventor Norio Iizuka 2-27-7 Taito, Taito-ku, Tokyo Inside Hitachi Battery Sales Service Co., Ltd. (72) Yoshinari Morimoto 2-8-7 Nihonbashi Honcho, Chuo-ku, Tokyo Shin-Kobe F-term (reference) in Denki Co., Ltd.

Claims (9)

[Claims] When the remaining capacity of a storage battery used as a power source of an electric starter such as a starter motor for starting an internal combustion engine becomes smaller than a capacity required for driving the electric starter at least once or more. A method of interrupting the supply of power from the storage battery to a load to prevent the storage battery from being over-discharged, wherein a discharge amount and a charge amount of the storage battery are calculated, and from the calculation result, Calculating the remaining capacity of the storage battery and, when the remaining capacity obtained by the calculation becomes smaller than a predetermined value, interrupting the supply of power from the storage battery to the load; overdischarging the storage battery. Prevention method. 2. When the number of charging / discharging of the storage battery reaches a predetermined number, the internal resistance of the storage battery in a fully charged state is measured, and a deterioration state of the storage battery is determined based on the internal resistance. The method according to claim 1, wherein the capacity of the storage battery in a fully charged state is corrected based on the determination result. 3. The over-discharge prevention method for a storage battery according to claim 2, wherein when the internal resistance is measured, the electrical connection between the storage battery and the load is cut off. 4. The state of a storage battery used as a power source of an electric starter such as a starter motor for starting an internal combustion engine is monitored, and the remaining capacity of the storage battery drives the electric starter at least once. A storage battery monitoring device that outputs an alarm signal when it detects that the required capacity is less than the required capacity, and when the storage battery monitoring device outputs the alarm signal,
An overdischarge prevention device for a storage battery, comprising: switch means for interrupting supply of power from the storage battery to a load, wherein the storage battery monitoring device calculates a charge and discharge amount for calculating a discharge amount and a charge amount of the storage battery. Means, a remaining capacity calculating means for calculating the remaining capacity of the storage battery from the calculation result of the charge / discharge amount calculating means, and when the remaining capacity obtained by the remaining capacity calculating means becomes smaller than a predetermined value. An overdischarge prevention device for a storage battery, comprising: a remaining capacity determination unit that outputs the alarm signal. 5. The storage battery monitoring device includes: an internal resistance measuring unit that measures an internal resistance of the storage battery in a fully charged state when the number of times of charging and discharging of the storage battery reaches a predetermined number; Deterioration state determination means for determining a deterioration state of the storage battery based on the internal resistance measured by the means, wherein the remaining capacity calculation means is in a fully charged state based on the determination result of the deterioration state determination means. The storage battery over-discharge prevention device according to claim 4, wherein the capacity of the storage battery is corrected to calculate the remaining capacity of the storage battery. 6. The storage battery monitoring device according to claim 5, wherein when the internal resistance measuring unit measures the internal resistance, the storage battery monitoring device outputs the alarm signal to turn off the switch unit. 2. The storage battery overdischarge prevention device according to claim 1. 7. A storage device comprising: a use state detecting means for detecting a use state of a battery such as a discharge electricity amount and a charge electric amount of a storage battery; and a use state history storage means for storing a detection result of the use state detection means as history. A storage battery monitoring device. 8. A storage battery replacement time determining means for determining a replacement time of the storage battery from the history stored in the usage history storage means and outputting a storage battery replacement warning signal when it is determined that the replacement time has been reached. The storage battery monitoring device according to claim 7, further comprising: 9. A monitoring device for a storage battery that requires replenishment of an electrolyte, comprising: a water level detection means for detecting a water level of the electrolyte of the storage battery;
A storage battery monitoring device, comprising: a water level determination means for outputting an electrolyte replenishment alarm signal when the water level detected by the water level detection means repeatedly falls below a predetermined level.