JPH11313445A - Charging of lead-acid battery and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce charging time by parallel-connecting a plurality of lead-acid batteries to a charging apparatus for charging, and avoid overcharging and the shortage of charging by discriminating the time, at which charging of respective batteries has been completed properly by means of a full-charge discriminating circuit. SOLUTION: A plurality of batteries B1 , B2 , B3 are parallel-connected with a constant current-voltage charging apparatus 2, and during a charging period by a constant current charging system, the respective batteries or respective groups of batteries connected in parallel are charged appropriately by switching selection switches S1 -S3 . When all the batteries reach a fixed charging voltage, switching to constant voltage charging system is conducted, so that the respective batteries connected in parallel are charged at constant voltage. The terminal voltage of the respective batteries is sampled continuously within this period. Based on the fluctuations in a measured terminal voltage value, the fully-charged conditions of respective batteries are discriminated respectively by means of a full-charging discriminating circuit provided in a controller 4, the fully-charged batteries and charged additionally for a fixed period to have the charging finished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for charging a lead storage battery using a charging power source, and more particularly to vehicles such as general automobiles, golf carts, forklifts, wheelchairs, electric automobiles, vacuum cleaners and the like. The present invention relates to a charging method and a device suitable for charging a lead storage battery for a vehicle or a lead storage battery for a cycle used in a vehicle.

[0002]

2. Description of the Related Art In general, a 12V battery of 2V.times.6 cells is used as a lead-acid battery for use in a vehicle or for a cycle. When charging the battery, as shown in FIG. Two or three storage batteries B1 to B3 are connected in series to 51, and two batteries are regarded as 24V and three batteries are regarded as 36V, and charging is performed using a charging power supply device corresponding thereto. . In the figure, 1 is an AC power supply,
52 is a transformer, 53 is a rectifier, and 54 is a load.

[0003] However, in practice, individual lead-acid batteries have different remaining electric capacities, and therefore, the timing of full charge differs even when the same charging device is used.
As a result, it is unlikely that the whole will be fully charged at the same time,
Some were overcharged, while others were undercharged.

When a plurality of batteries are connected in series and charged,
Since the specific gravity increases from the lead storage battery near the minus pole, the lead storage battery near the minus pole tends to be overcharged, while the lead storage battery near the plus pole tends to be undercharged.

[0005]

Therefore, a method is considered in which the terminal voltage of each lead-acid battery is measured during charging, and when the voltage reaches a certain level, it is considered that the battery is fully charged. However, the new lead-acid battery and the old lead-acid battery have different full-charge terminal voltages, and the older lead-acid battery has a lower fully-charged terminal voltage, and thus has the disadvantage of easily falling into overcharge. In particular, if the sealed storage battery is overcharged, not only will the electrode become unreproducible, but the storage battery will also explode due to oxygen gas generated inside, so it is extremely important to determine the timing of full charge. It is.

[0006] The present invention eliminates the above-mentioned drawbacks and provides a method for simultaneously charging a plurality of lead-acid batteries using the same charging device.
It is a first object of the present invention to provide a charging method and an apparatus for fully charging all lead-acid batteries in a short time and in a uniform state.

A second object of the present invention is to provide a charging method and a device capable of simultaneously charging a large number of lead-acid batteries in a short time even if a small-capacity charging device is used. It is.

A third object of the present invention is to provide a low-cost charging device for a lead storage battery which is lightweight, easy to carry, and can be directly mounted on a car or equipment. is there.

[0009]

Means for Solving the Problems When charging a lead storage battery at a constant voltage, the present inventors consider that the terminal voltage of the lead storage battery becomes stable and does not fluctuate when the full charge time is reached. It has been found that the above object can be achieved by grasping empirically and using this phenomenon as a means for judging full charge.

That is, according to the method of charging a lead storage battery of the present invention, a method of connecting a plurality of storage batteries in parallel to a charging power source and charging the battery until the charging voltage reaches a preset voltage set value. After charging by the current charging method and reaching the voltage set value, charging is performed by the constant voltage charging method while sampling and measuring the terminal voltage of each storage battery, and the measured sampling value is substantially over a certain period. It is characterized in that it is determined that the storage battery is no longer fluctuated, that the battery has been fully charged, predetermined additional charging is performed, and then charging is sequentially terminated.

In the present invention, the target lead storage battery includes not only a lead storage battery for general vehicles but also a lead storage battery for cycles used in golf carts, forklifts, wheelchairs, electric vehicles and the like. In addition to standard lead-acid batteries that use antimony alloys as lattice alloys, lead-acid batteries that use calcium alloys (commonly known as calcium storage batteries)
Is also included as a target. Further, the charging method and device of the present invention can be used for a closed lead storage battery as well as a normal open lead storage battery.

According to the charging method of the present invention, the battery is charged by a constant current charging method at first, and the charged amount of the storage battery is approximately 80% to 85%
%, It switches to the constant voltage charging method. The set voltage for this switching is 17.2V to 17.5V
(16 Vmax in the case of a calcium battery) is a standard.

At the same time as charging by the constant voltage charging method is started, sampling of the terminal voltage is started. As a full charge determination method, after shifting to the charging period by the constant voltage charging method, the terminal voltage of each storage battery is individually measured at a fixed cycle, and the time when the measured value does not substantially fluctuate over a certain period is determined. It is determined that the battery is fully charged.

Here, the fact that the measured value of the terminal voltage does not substantially fluctuate means that the measured values are exactly the same or the fluctuation range is ± 1/1.
It means the case of 100V to 1 / 20V. In other words, in the case of a standard lead-acid battery, when charged by the constant current charging method, about 4 to
The charging voltage reaches almost 17 V in 5 hours. The terminal voltage at this time is approximately 16 V, but hardly increases beyond that.

The period during which the measured value does not fluctuate (hereinafter referred to as a stable state of the terminal voltage) continues for 3 ± 1 hours after the terminal voltage becomes approximately 16 V, and thereafter, −
The period shifts to a period of ΔV, a so-called overcharge period.

The sampling of the terminal voltage is performed, for example, for each storage battery at one-minute intervals. Then, for each storage battery, the first measured value V (i) of the terminal voltage is set as the first reference value Vs, and is compared with the next measured value V (i + 1). When they match, that is, when they match within an error range of ± 1/100 to 1 / 20V, the next measured value V (i +
2) is read and compared with the reference value Vs.

However, for example, the n-th measurement value V (i +
If n) does not match the reference value Vs, the n-th measurement value V (i + n) is set as a new reference value Vsn and compared with the next measurement value. In this way, the latest set value is sequentially compared with the subsequently read measurement value, and the number K of times when they match is recorded. When the value of K reaches the threshold value N, it is determined that the battery is fully charged.

The "fixed period in which the measured value does not substantially fluctuate", which is the basis of the judgment of full charge, is empirically 10 to 40 minutes, preferably 15 to 20 minutes. When the charge rate of the storage battery reaches about 80%, the terminal voltage may not fluctuate for a short time, for example, for 5 to 6 minutes.
Setting a threshold value smaller than 10 minutes is not preferable because there is a risk of causing a determination error of full charge.

Further, even when the terminal voltage reaches a stable state, the terminal voltage may increase instantaneously due to disturbance or the like. In this case, the number of times of matching is counted again from the reference value set next to the abnormal value due to the disturbance. Since the stable state of the terminal voltage usually lasts 3 hours ± 1 hour, setting the threshold longer than 40 minutes requires additional charging (usually 40 minutes to 1 hour).
It is not preferable because it may not be completed within the period of the stable state. Therefore, this threshold value N is 10 to 40 when sampling at one minute intervals, preferably 15 to 40.
20.

In the case of a calcium storage battery, since the terminal voltage of the fully charged battery is about 1 V lower than that of the standard lead storage battery, the determination of the timing of switching from the constant current charging to the constant voltage charging and the set voltage of the constant voltage are all standard. It is set to be about 1 V lower than in the case of a lead storage battery. Further, the voltage setting value of the charging voltage used for the determination of switching from the constant current charging to the constant voltage charging may be equal to the constant voltage setting value in the constant voltage charging period, but it is better to set the voltage slightly lower than that. This is preferable in system design.

Usually, a 100 V or 200 V AC commercial power supply is used as a power supply for charging a constant current and a constant voltage of a lead storage battery. As a constant current / constant voltage charging device for converting an alternating current into a direct current, a thyristor type, a transistor type, a switching regulator type, or the like is generally used. In particular, switching regulator type constant current / constant voltage chargers are lightweight, small and excellent in portability, but large capacity ones are difficult to manufacture and are not on the market.

Therefore, according to the present invention, in the method of charging by connecting a large number of storage batteries in parallel to the constant current / constant voltage charging device, the period of charging by the constant current charging method is for each storage battery or in parallel. By separately charging each group of a plurality of connected storage batteries, it is possible to charge a large number of storage batteries simultaneously in a short time even when using a small-capacity transistor type or switching regulator type. Was.

A charging device for realizing the charging method of the present invention is a constant current / constant voltage charging device; an output of the constant current / constant voltage charging device is supplied to a plurality of storage batteries via a power line connected in parallel. A charging connector having a plurality of connection terminals for performing charging; a voltage measuring device for measuring a terminal voltage of each storage battery; a timer for measuring a charging time; A changeover switch for opening and closing the connection between the terminals and a controller for controlling opening and closing of the changeover switch are provided.

This controller performs charging by a constant current charging method until the charging voltage of each storage battery reaches a preset voltage set value, and after all storage batteries have reached the above-mentioned voltage set value, the controller performs charging. The constant current / constant voltage charging device is controlled so as to perform charging by the constant voltage charging method, and during the period of charging by the constant voltage charging method, the charging current is supplied to all the storage batteries in parallel. , Measure the terminal voltage of each storage battery at regular intervals,
The opening and closing of the changeover switch is controlled so that charging is terminated in order from the storage battery whose measured value does not fluctuate for a certain period.

[0025] Further, during the period in which charging is performed by the constant current charging method, the controller sets the changeover switch so as to perform charging individually and sequentially for each storage battery or for each group of a plurality of storage batteries connected in parallel. It is configured to control opening and closing.

Further, the controller includes a sampling circuit for measuring the terminal voltage of each storage battery individually at a constant period, and a state of full charge of each storage battery based on a fluctuation of the terminal voltage of each storage battery measured by the sampling circuit. And a switching signal output circuit that outputs a signal for disconnecting the connection between the constant current / constant voltage charging device and each storage battery in accordance with the determination result of the full charge determination circuit. ing.

A current limiting element is inserted between the constant current / constant voltage charger and the connection terminal of each storage battery. As a result, even if a large current flows during the constant voltage charging period, the current is automatically cut to ensure the safety of the device and the storage battery and to ensure the uniformity of the charging voltage.

As the current limiting element for this purpose, a nichrome wire, a thyristor or the like can be used, but a nichrome wire which is inexpensive and has excellent operability is most preferable.

[0029]

FIG. 1 shows an example of a charging circuit using a constant current / constant voltage charger. Reference numeral 1 denotes an AC power supply, and 2 denotes a transistor type constant current / constant voltage charger. It is configured so that it can be switched to four stages. Reference numeral 3 denotes a charging connector. In this example, connection terminals B11 and B1 are connected so as to supply charging current to three storage batteries B1, B2 and B3 in parallel.
2; B21, B22; B31, B32 are provided.

S0 is a relay for opening and closing the circuit of the AC power supply, S1 is a relay provided on the line connecting the charging device 2 and the storage battery B1, and S2 is provided on a line connecting the charging device 2 and the storage battery B2. The relay S3 is a relay provided on a line connecting the charging device 2 and the storage battery B3. S
Reference numerals 4, S5, S6 and S7 are relays for switching the output voltage of the constant current / constant voltage charging device 2, and S4-S5-S6-S7
The output voltage rises by 1V each time is switched.

4 controls the operation of the constant current / constant voltage charger 2 and relays S in accordance with the terminal voltage of each storage battery.
A controller for controlling the opening and closing of S1, S2 and S3. L0 is a measurement line for measuring a current, L1 is a measurement line for measuring a terminal voltage of the storage battery B1, L2 is a measurement line for measuring a terminal voltage of the storage battery B2, and L3 is a terminal voltage of the storage battery B3. This is a measurement line for performing

T0 to T3 are transistors for amplifying the current or terminal voltage of each storage battery, and T4 to T11 are transistors for controlling the relays S0 to S7. R
0 is a shunt for measuring current.

R1 is a current limiting element inserted on a line connecting charging device 2 and storage battery B1, R2 is a current limiting element inserted on a line connecting charging device 2 and storage battery B2, R
Reference numeral 3 denotes a current limiting element inserted on a line connecting the charging device 2 and the storage battery B3.

As shown in FIG. 2, the controller 4 includes a control unit 41 for controlling the constant current / constant voltage charging device 2 and the like.
A sampling circuit 42 for sampling the terminal voltages of the storage batteries B1 to Bn, an open / close signal output circuit 43 for selectively opening and closing the changeover switches S1 to Sn provided between the charging device 2 and the storage batteries B1 to Bn. It has a timer 44 for controlling and a memory 45 for storing the sampling value. Further, the control unit 41 includes a full charge determination circuit 411 for determining full charge, and the like.

Next, the operation of the charging circuit will be described. First, three calcium storage batteries B1, B2, and B3 are connected to the charging connector 3 in parallel. Then, the relay S0 is closed and the AC power supply 1 is connected to the constant current / constant voltage charging device 2.

First, the storage battery B1 is charged at a constant current. For this purpose, the relay S1 is closed and the relays S2, S
Open 3. The relay S4 of the charging device 2 is closed and the relay S
5. Open S6 and apply 11V output voltage to the storage battery 1.

As shown in FIG. 4, when the set value Ic of the constant current is initially set to about 15 A, the charging current Ix decreases with time. This current value is always measured in units of microseconds. When the current Ix decreases to the lower limit value Ia of 12 A or less, the controller 4 switches the relay from S4 to S4.
5 to increase the output voltage by 1V. The current Ix rises again, but drops again after a while. When the current again falls below the lower limit, the relay is switched from S5 to S6 to increase the output voltage by 1V.

The charging voltage of the storage battery B1 is 1 of the set voltage Va.
When the voltage reaches 5 V (point A), the controller 4 switches the relay from S1 to S2 and connects the charging circuit of the storage battery B2. The same constant current charging as that of the storage battery B1 is performed on the storage battery B2. Thus, all the storage batteries B1 to B3
Reaches the set voltage, the controller 4 operates the relay S1
To S3 are closed, and the storage batteries B1 to B3 are connected in parallel to the constant current / constant voltage charger 2 so that the charging voltage is set to the constant voltage set value Vc of 16 V and constant voltage charging is started. The current / constant voltage charging device 2 is controlled.

When the constant voltage charging is started, each of the storage batteries B1 to B
The terminal voltage Vi of No. 3 gradually rises as shown in FIG. 4, but eventually becomes flat and hardly changes. In this figure, the curve of the terminal voltage for one typical storage battery is recorded. In practice, the curve of the terminal voltage different for each storage battery is recorded.

On the other hand, simultaneously with the start of the constant voltage charging, the sampling of the terminal voltage is started. The sampling of the terminal voltage is performed at one-minute intervals for each storage battery. Storage batteries B1 to B3
Are amplified by the transistors T1 to T3 via the lines L1 to L3, respectively, and taken into the controller 4.

The terminal voltage Vi measured first is the reference value V
is set in the memory as s, and the next measured value V (i + 1)
Is compared to Error range with the difference (± 1/100 ~
In the case of 1 / 20V), it is considered that there is no change, and the measured value V (i + 2) read next is compared with the reference value Vs. When the measured value does not substantially fluctuate, that is,
When the stable state of the terminal voltage is maintained for a certain period of time, for example, 15 minutes (B-C in the figure), the storage battery is considered to be fully charged. Then, after the additional charge is performed for a predetermined time, for example, 40 minutes (CD in the figure), the charge is terminated. Note that ΔV indicates overcharge.

A flow chart of a current control circuit for constant current charging using a microcomputer of the controller 4, a circuit for shifting from constant current charging to constant voltage charging, and a circuit for determining full charge will be described with reference to FIG.

First, the voltage of the storage battery to be charged is measured, the initial charging voltage is determined, and charging is started by the constant current charging method. At the same time, the charging current is measured at regular intervals. When the measured charging current Ix is larger than the set value Ia, the charging current is measured again. When the charging current Ix is equal to or lower than the set value Ia, the charging voltage is measured. When the measured value Vx of the charging voltage becomes lower than the set value Va, the charging voltage is increased by, for example, 1V.

By repeating this loop, charging is maintained while the charging current is kept substantially constant. When the measured value Vx is equal to or greater than the set value Va (point A in FIG. 4), a charging voltage Vc for constant voltage charging is set, and thereafter, charging is performed by the constant voltage charging method. continue.

During the constant voltage charging period, the terminal voltage of the storage battery is measured at regular intervals. First, the first measured value Vi is set in the memory as the reference value Vs. Then, the next measured value V
(I + 1) is compared with the reference value Vs. If both match, the accumulative count counter is added, and the next measured value V
(I + 2) is compared with the read reference value Vs. If they match, the counter is incremented. If the number K becomes equal to the set value N, it is considered that the terminal voltage has not changed for a certain period of time, and it is determined that the battery has been fully charged.

However, if the measured value V (i + n) does not coincide with the reference value Vs in the middle, the measured value V (i + n) is set as a new reference value Vsn, and at the same time, the accumulated number K of the coincidence number counter is incremented. clear. And newly,
The comparison between the reference value Vsn and the subsequent measured values is started.
When the counter number K reaches the set value N, it is determined that the battery is fully charged. The storage battery that has been determined to be fully charged is further charged for a predetermined time, and charging is completed.

In this embodiment, in the full charge determination circuit, the measured value of the terminal voltage is compared with the measured value taken first or the measured value newly taken immediately after the mismatch, and this reference value Values are compared with subsequent measurements. In contrast, when the immediately preceding measured values are compared with each other, according to the method of the present invention, an allowable range (± 1/100 V to 1/20 V) is provided in the condition for matching the measured values. Cumulative and dangerous. On the other hand, according to the method of the present invention, the maximum error is within the above-mentioned allowable range, no matter how many times the number of matches is increased.

Further, in this embodiment, during the constant current charging period, since the storage batteries are charged one by one, the capacity of the charger can be small, but there is a disadvantage that the charging time is long. Therefore, when the storage batteries are charged in groups of two, the capacity of the charger is reduced to two thirds as compared with the case where three batteries are simultaneously charged, and the charging time is reduced to one half compared with the case where the storage batteries are charged one by one. become.

Further, in the case of charging by grouping two batteries at a time, if two batteries are combined by being shifted by a half cycle (at first,
(Only half of the battery is charged.) The capacity of the charger is half that of the case where three batteries are charged simultaneously, and the charging time is slightly more than half that of the case where one battery is charged one by one.

[0050]

According to the method and the apparatus for charging a lead storage battery of the present invention, full charge is determined based on a state where the sampling value of the terminal voltage of the storage battery being charged does not substantially fluctuate for a certain period. Therefore, when charging multiple batteries at the same time, it is possible to always detect the correct state of full charge for each battery, regardless of whether the battery is old or new or the amount of remaining electricity, and avoid overcharging and insufficient charging can do.

In the method and apparatus for charging a lead storage battery according to the present invention, the battery is charged by a constant current charging method until the charging voltage reaches a preset voltage set value. Are charged in a constant voltage charging mode in a state of being connected in parallel to the battery, so that the charging time can be reduced.

In the method and the apparatus for charging a lead storage battery of the present invention, the batteries are connected for each individual storage battery or in parallel during the period of charging by the constant current charging method, that is, the period of consuming the largest amount of power. Since charging is performed individually and sequentially for each group of a plurality of storage batteries, charging can be performed using a charging device having a small electric capacity.

Further, by individually and sequentially charging during the charging period by the constant current charging method as described above, it is possible to use a transformerless charging device having a relatively small capacity and a light weight. In addition, it is possible to realize a device configuration of a charger mounted type in a lightweight device such as a vacuum cleaner.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a charging device of the present invention.

FIG. 2 is a block diagram showing a configuration of a controller in the apparatus shown in FIG.

FIG. 3 is a software flowchart of a constant current / constant voltage control means in the apparatus of FIG. 1;

FIG. 4 is a graph showing charging characteristics of the present invention.

FIG. 5 is a circuit diagram of a conventional charging device.

[Explanation of symbols]

 Reference Signs List 1 power supply 2 constant current / constant voltage charger 3 charging connector 4 controller

Claims (6)

[Claims] In a method of charging a plurality of storage batteries connected in parallel to a charging power source, charging is performed by a constant current charging method until a charging voltage reaches a preset voltage set value. After reaching the value, the storage battery was charged by the constant voltage charging method while sampling and measuring the terminal voltage of each storage battery, and the storage battery from which the measured sampling value did not substantially fluctuate for a certain period was fully charged. A method of charging a lead storage battery, comprising: performing a predetermined additional charge upon completion of the charge; and sequentially terminating the charge. 2. A period for charging by the constant current charging method is as follows:
2. The method for charging a lead storage battery according to claim 1, wherein the charging is performed sequentially for each individual storage battery or for each group of a plurality of storage batteries connected in parallel. 3. A constant current / constant voltage charging device;
A charging connector having a plurality of connection terminals for supplying an output of a constant voltage charging device to a plurality of storage batteries via power lines connected in parallel; a voltage measuring device for measuring a terminal voltage of each storage battery; a charging time A switch for opening and closing a connection between a terminal of the constant current / constant voltage charger and a terminal of each storage battery; and a controller for controlling opening and closing of the switch. The controller charges each storage battery by a constant current charging method until the charging voltage of each storage battery reaches a preset voltage set value, and after all the storage batteries reach the above-mentioned voltage set value, the controller performs constant voltage charging. The constant-current / constant-voltage charging device is controlled so that each storage battery is charged according to the method, and charging is performed by the constant-voltage charging method during the entire period. While supplying the charging current to the storage batteries in parallel, the terminal voltage of each storage battery is measured at a fixed period, and the charging is terminated in order from the storage battery whose measured value of the terminal voltage has not fluctuated for a certain period. A lead-acid battery charging device configured to control opening and closing of the changeover switch. 4. The change-over switch according to claim 1, wherein during the period of charging by the constant-current charging method, charging is performed individually and sequentially for each storage battery or for each group of a plurality of storage batteries connected in parallel. The lead-acid battery charging device according to claim 3, wherein the device is configured to control opening and closing of the battery. 5. A controller according to claim 1, wherein said controller measures a terminal voltage of each storage battery individually at a constant period, and a state of full charge of each storage battery based on a fluctuation of a terminal voltage of each storage battery measured by the sampling circuit. And a switching signal output circuit that outputs a signal for disconnecting the connection between the constant current / constant voltage charging device and each storage battery in accordance with the determination result of the full charge determination circuit. The charging device for a lead storage battery according to claim 3 or 4, wherein: 6. The lead storage battery according to claim 3, wherein a current limiting element is inserted between the constant current / constant voltage charger and a connection terminal of each storage battery. Charging device.