JPH01206847A - Method and apparatus for charging lead cell - Google Patents

Abstract

PURPOSE: To reduce a gas generation amount in a bubble generating stage of the charging process of a lead storage battery, without elongating its charging time, by making the charging voltage - current characteristic curve every its cell intersect a bubble generating level at 0.5 I when I is its nominal load current, and by making the gradient of the characteristic curve about -0.5V/I--0.1V/I. CONSTITUTION: In a charging process according to the present invention, the charging current of a cell is maintained in a fixed value I5 until a cell voltage Uc reaches the bubble generating level of 2.4V to follow an I characteristic 1. Thereafter, the charging current follows a U-characteristic 2 until it lowers to 0.5 I5 to intersect thereafter a voltage axis of ordinate at 2.5V per cell, following a W-characteristic 3. Thereby, a gas generation amount in the charging process of a lead storage battery can be reduced without increasing its charging time beyond an allowable range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a charging method and a charging device for a lead-acid battery.

[Prior art and its problems]

The life of lead-acid batteries in cyclic operation depends to some extent on the recharging process, where relatively deep discharges and recharging are repeated frequently, for example in electric vehicles. Recharging should be done as slowly as possible, but usually only at inconvenient times, such as nights between two working days or on weekends.

The capacity of lead-acid batteries is usually expressed in ampere-hours (person-h). A nominal load current 6 is also specified on the basis of capacity. The nominal load current is equal to the capacity divided by 5 hours, and if the load current is I5, the battery will be completely discharged in 5 hours. Normally, when this load current specifies the characteristics of a storage battery, a charging current larger than rH is usually not used. Note that the above charging current value is called a "nominal current" or "rloochi charging current".

When charging a lead-acid battery, almost as soon as the cell voltage exceeds the so-called bubbling level of 2.4V (this value depends somewhat on temperature), a portion of the charging current dissociates the water in the battery chamber, Hydrogen and oxygen are generated and the acid is intensely heated.

The amount of gas generated increases in proportion to the strength of the current.

In this so-called bubbling stage, intense bubbling causes corrosion of the battery grate material.
Excessive load is placed on the storage battery.

As we all know, it only takes 1 charge! This is done by connecting a current source (charging device) to the terminals of the storage battery. The subsequent state of charging progress is determined by the output characteristics of the charging device and the characteristics of the storage battery being charged.

Regarding the output characteristics of charging devices, various technical standards have been defined, particularly in order to protect storage batteries. The West German standard (DIN 41772) provides a general overview of the characteristics of the different types and a simple provision for them.

When the output voltage is approximately constant (±2% of the nominal value) over all ranges of current values, the output characteristic is called the U characteristic. When the output current is approximately constant (±2 degrees of the nominal value) over a range of voltage values, the output characteristic is called an I characteristic. The output characteristic, in which the output current decreases and the output voltage increases, is called a W characteristic. U
, LW designation is commonly used in the field of charging devices.

When charging a storage battery, the plurality of characteristics described above may be partially repeated in a certain order. According to DIN 41772, it is common practice to combine the above-mentioned instruction letters in an order corresponding to the charging process;
It is used as a code to represent the function of the charging device. In this method, there are many types of charging devices such as W type, IUW, and W type.

In the W-type charging device, the transformer with rectifier has the following characteristics (power hyperbota).
), it can be constructed very easily.

That is, regarding this type of charging device for lead-acid batteries, DI
The main provisions of N41774 are that the device supplies 5% at a cell voltage of 2V, and at a cell voltage of 2.4V (bubble generation level), the charging current value drops to 5% of 2.
At a cell voltage of 65V, the current value must drop to 25% of the current value.

IUW for lead-acid batteries as specified in DIN 41773
Type and ROR type charging devices are currently relatively widely used. In such devices, charging usually begins with
at a constant current (■characteristic), in which case the cell voltage increases until it reaches the bubble generation level. The voltage is then maintained at the bubble generation level to follow the U characteristic. In the U-characteristic stage with , the charging current decreases corresponding to the upward charging of the battery.

Continuing to charge at a constant voltage reduces the charge current to an excessively low value, requiring unacceptably long charging times for batteries operating in cycles. The charging current is Is
After that, in the IUW method, the output characteristic of the charging device changes to the next W characteristic. Its W characteristic intersects the voltage axis at a cell voltage of 2.7v, specifically 2.7v per cell for the accumulator when the charging device is idle or when the charging current is equal to zero. 7
The voltage supply of V must be cut off. In the IUI charging device, when the charging current decreases to 20 inches (workability), the current is changed again to a constant current (workability).

In the above-mentioned IUW type and IUI type charging devices, generally when the storage battery is sufficiently charged, the charging process must be stopped manually or by automatic time control, and if not stopped, the W stage and Due to the strong bubble generation in the second processing stage, υ
, there is a strong possibility that destructive effects will be exerted on storage batteries.

〔the purpose〕

The present invention relates to this known technology, and in the method for charging a lead-acid battery as described in the preamble of claim 1, the charging time is not substantially extended, and the gas generated at the bubble generation stage is The purpose is to provide a method that reduces the amount required.

[Summary of the invention]

As described in the characteristic part of claim #c1,
Control the charging current and charging voltage for each storage battery cell to be higher than the bubble generation level, make the characteristics of the current and voltage approximately linear, and cross the bubble generation level at about 0.5I,
The above objective can be achieved by setting the gradient to approximately -o, sv/rs to -0, IV/I.

According to the present invention, the charging voltage and charging current above the bubble generation level are controlled according to the W characteristic having a slope that is smaller than the slope proposed so far. It has been found that charging according to such characteristics substantially reduces the amount of gas generated without increasing the charging time to unacceptable limits.

When the charging current drops to almost zero, conventional technology
In the last part of the charging phase the voltage increases relatively rapidly, but according to the invention such a phenomenon is prevented. Due to the reduced gas production and reduced voltage load, the battery life is increased.

According to the embodiment of the present invention as set forth in claim 2, the charging characteristic above the bubble generation level has a slope of about -0.
, 2V/1. and crosses the bubble generation level at about 0.5 Ia. When charging a lead-acid battery according to this characteristic, when the battery is in a 25-channel discharge state (i.e., when the residual capacity of 75 meters is in a fully charged state), the charging time increases by about 30%, and the bubble generation stage The amount of gas generated at is DI
Even in the case of charging during the charging process exceeding the bubble generation level according to the wg characteristics specified in N41773 or DIN41774, the charging time is approximately 0% less υ, and when the storage battery is in an 80% discharged state, the charging time is approximately 12 times The length increases, and the amount of gas generated decreases by about 30 times.

In the charging device according to the present invention for carrying out the method of claim 1 or 2, the charged Wa flow decreases and the charging voltage increases above the bubble generation level according to the linear characteristic. a controllable charging current source, a current sensor, a voltage sensor for the storage battery, and a control device connected to the current source and both sensors for controlling the charging process; As set forth in claim 3, the control device includes a controller for converting the sensor signal into an indication signal indicating whether the charging current and the charging voltage follow desired linear characteristics. At least one converting device and at least one regulating device are provided for comparing the indication signal with a reference signal to control the charging current source to modify the charging current and charging voltage to follow a linear characteristic. It is.

In this way, the adjustment is performed simply by means of an adjustment device that compares the indication signal with a constant reference signal. Such a regulating device can, as is known, consist of an operational amplifier with a suitable coupling, the output signal of which is converted into a control signal for the charging current source. Couplings for this purpose are well known, and generally in charging devices the rectifier of the charging current source is provided with a thyristor coupling, the control of which is controlled by a continuous or sampling regulator that receives an input signal from a comparator of the type mentioned above. This is done by controlling the switch-on time of the thyristor.

According to claim 4, the instruction signal can be generated regardless of the coefficient by weighted addition of signals proportional to the charging current and the charging voltage.

In this embodiment, the relationship between the weights of the plurality of signals determines the slope of the characteristic determined by addition while the instruction signal remains constant. To put it simply, for example, when the charging current changes, the charging voltage also changes accordingly, and this relationship is determined by the weight of the signal in the addition, so the instruction signal corresponds to the addition result. , constant i
Sometimes things come together. The resulting characteristic is linear.

According to claim 5, the converting device is constructed by connecting a voltage divider between two voltage generators.
It can be constructed very simply, in which the indication signal is collected between several resistors of the divider. As well as the conversion ratio of the voltage generator, the resistance ratio of the voltage divider also plays a role in determining the slope of the characteristic that the charging current and charging voltage follow in order to keep the indication signal constant.

In the embodiment according to claim 6, the charging device can be adjusted for accumulators of different capacities, in which case the weight of the charging current is responsible for determining the output characteristics of the device. Adjustments to the charging device can be made by adjusting a single regulator that controls the charging device. As described in claim 7, it is effective to arrange the adjustment device on the operation panel so that the charging device can be adjusted manually.

Preferred embodiments of the voltage generator and regulating device are set out in claims 8 and 9.

〔Example〕 Next, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, in the charging process according to the present invention, until the cell voltage (Jc) reaches the bubble generation level of 2.4V,
The charging current is kept at a constant value x and follows characteristic 1. Then, until the charging current drops to 0.5I, U
According to characteristic 2, then W characteristic 3 and so on, 2.
Intersects the voltage axis at 5v.

Comparing the charging method according to the present invention with the known method shown by the broken line, the known method follows the U characteristic 2 at o, zrfit, and then becomes the W characteristic 4, which has a clearly steeper slope than the case of the present invention, It intersects the voltage axis at υ2.7v per cell of the storage battery.

The charging device according to the present invention shown in the block diagram in FIG.
Its output characteristics correspond to the characteristics shown in FIG. The accumulator 10 is connected to a controllable charging current source 20 . The charging current source 20 is provided with a transformer for lowering the supplied AC voltage and a thyristor-shaped rectifier, and the output current and output voltage thereof are controlled by the switch-on time of the thyristor. It can be controlled by. Such charging current sources are known.

Control signals for the thyristors are supplied from a control circuit 30.

The circuit 30 receives a modification signal from a network 40 of NAND logic circuits which causes the switch for the thyristor to modify the output current and output voltage of the charging current source to correspond to the desired output characteristics. It is indicated whether the on point needs to be moved forward or backward in time.

To generate the correction signal, the charging current source is provided with two signal output terminals 50, 60, the output voltages of which are proportional to the charge N, current and charge tW pressures, respectively. The signal at the output terminal 50.6O-II' is filtered and normalized, and Ov and a predetermined maximum value (
8V'), and in that case a normalizing amplifier 70,80 is used. Current signal 55 is then provided to input terminal 101 of comparator 100. The other input terminal 102 of the comparator 10 receives a reference voltage from a reference voltage generator 140. Voltage signal 65 is provided to an input terminal 121 of comparator 120, and another input terminal 122 of comparator 120 receives a reference voltage from generator 140.

By combining signals 55.65, converter 1
At 50, an indication signal 160 is formed. As long as the output voltage of the charging current source 20 follows part 3 of the characteristic shown in FIG. 1, the indication signal is constant. Next, the conversion device f150 will be explained in detail. The indication signal 160 is compared at one input terminal 131 of the comparator 130 with a reference voltage supplied from the generator 140 to the other input terminal 132 of the comparator.

The reference voltage of the input terminal 102, 122, 132 is selected appropriately, specifically, the output signal 1 of the comparator 100
03 is full 1! ! Depending on whether the current is greater than or less than 15, the comparator 120 switches the output signal 123 at a charging voltage of 2.4 V per cell, and the comparator 130 is formed by the converter 150. The output signal 133 is switched depending on whether the voltage of the instruction signal is above or below the above-mentioned constant value (that is, the constant value that must be followed in order to comply with characteristic part 3 regarding the charging current source). .

From the output/wake number of comparators 103.123.133, the actual charge is 1! It can be read whether the current and the actual charging M1m and pressure are related to the output characteristics shown in FIG.

Furthermore, it can be read from the above output signal how to arrange the switch-on point of the thyristor to modify the actual state to desired characteristics. For example, output signal 103.123
When it is found that the charging voltage is less than 2.4 V per cell and the current is less than Is, it triggers the early switching of the thyristor of charging current source 2 and increases the output current in the direction of IsK. There is a need. Signal 103.
Similar logical conclusions apply for any combination of signal values occurring at 123.133.

The principles for advancing and retracting the switch-on point of the thyristor can be easily determined by a person skilled in the art from the characteristics shown in FIG. The input signal is the output signal 103.123.133 of the comparator, and the output signal is caused to switch between two values causing the ignition time of the thyristor to be advanced or retracted via the control circuit 30. The logic circuit shown in Figure 2 is composed of three NAND circuits, and by connecting them as shown, these circuits can be filled within the hatched area in Figure 1 or on its boundary. When there is 1m current and charging voltage,
The thyristor's ignition time is "advanced" and otherwise retracted.

The converter 150 and normalizing amplifier γ0.80 are shown in detail in FIG. The charging voltage is code 2
A charging current, schematically indicated at 10, is measured across the output terminals and supplied to a normalizing amplifier 80. The output voltage 85 (also indicated as Vy) is proportional to the charging voltage, and changes between 0 and 8V after being subjected to normalizing processing. The charging current is measured with respect to a series resistance at one of a plurality of output terminals of a charging current source, shown schematically at 220, and the measured voltage signal is proportional to the charging current, but the voltage The signal is provided to a normalizing amplifier 70. The output voltage is normalized and changes between O and 8V, but the voltage is determined by the potentiometer 230.
from which a signal voltage 55 (also denoted vx) is collected via its contact arm.

The potentiometer 230 measures the nominal charging current of the charging device 1.0 in relation to the capacity of the lead-acid battery to be charged. be used as a coordinating body to adapt the When the contact arm is closest to the normalizing amplifier 70, the small charging current will produce the same signal level in the contact arm as when the contact arm is in the center of the potentiometer; Normalizing amplifier 7 for the contact arm of the meter
By moving it to the 0 side, the value of the nominal charging current I decreases, and the armpit value becomes the basis for adjusting the output characteristics.

The conversion device 150 basically includes two operational amplifiers 25
0.260 followed by two resistors 270.280
It is made up of. Those operational amplifiers act as voltage generators, whose output voltages are connected to resistors 270.280 (
R,, R2) are combined to form a weighted sum. In this way, the signal voltage VaSVt is the non-inverting input terminal 2 of the operational amplifier 250, 260, respectively.
51.261, and the output voltage of the operational amplifier is supplied to the inverting input terminals 252.262. .

returned directly to. Resistors R1 and R2 are connected in series between the output terminals 253 and 263 of the operational amplifier, and the indication signal VW is collected from the connection point 290 between the resistors R1 and R1.

By appropriately selecting the resistor R1 and the RxO values, it is also possible to make the voltage Vw constant as long as the charging current and the charging voltage U comply with characteristic section 3 shown in FIG.

This is clear from the simple calculation below.

The change in charging voltage associated with the change in charging current for characteristic portion 3 can be expressed by the following equation.

(1) U = (Jo-aI In the above formula, U is the charging voltage, and ■ is the charging current.
, [3, is the open circuit output voltage of the charging device, a
is the slope of the sexual fluid part.

The charging voltage and charging current are converted into signals Vu and VxIi by an amplifier TO180 based on the following relational expression.

(2) [JO=bU=bUO−ILbI(3)
VI = cI In the above formula, b is the amplification coefficient or gain of the amplifier 80, sb, and C is the amplification coefficient or gain that appears in the combination of the resistance used for measurement, the amplifier 70, and the potentiometer 230.

The coefficients S, e may be determined before observing that the signals Vυ, Vl vary between O and a predetermined maximum voltage (SV in the example).

By coupling two operational amplifiers 250.2600 with resistors R1 and Rx as shown in FIG. 4, the signals Va and Vt are converted into the signal vw according to the following equation.

(4) Vw = Vu R*/ (Rs + Ih
)+Vt Rx/(Rx+R寞) In this equation, when U and I are expressed in their original expressions, they are as follows.

(5), Vw = b Uo R*/(Rt+R
z) -abI l' を い/(RI+R鵞) + e
I R1/(Rt+R2) As is clear from the above equation, the open circuit value of one voltage Vv (Eq=o) is as follows.

(6) In the case below Vwo=bUoRt/(Rt+Rz), the voltage vw becomes permanently equal to this value.

(7) Turtle bIR Goose/(R1+Rz)=c IRV(
Rs+lh) Accordingly, υ becomes as follows.

(8) 凰bRs=eRx or (9) Rt/u! = a b/c Therefore, since the coefficients S and c are known in advance, and considering the known rules for determining the specifications of operational amplifier circuits, the law for determining the specifications expressed by equation (9) can be calculated. R1 and R1 can be specified based on.

As is clear from the above calculation formula, the operational amplifier network shown in FIG.
Converts current and voltage signals. This can be called weighted addition, where the weight of the signal determines the ratio, but when the charging current changes to keep the weighted sum of the signals constant, the charging current must change according to that ratio. stomach.

FIG. 3 shows another example of the output characteristics of the charging device according to the present invention. In this example, two W characteristics 301
．． 302 is joined. Below the bubble generation level,
The W characteristic 301 varies as specified in DIN 41744, but the slope of the section 302 is reduced according to the invention.

As is clear from the above, in order to control the charging current and charging voltage of the charging device according to the two W characteristics shown in FIG. 3, two conversion devices as shown in FIG. A correspondingly modified logic circuit 40 may be provided alongside them. Such a device can be constructed by modifying the device of FIG.

In the embodiment of the charging device according to the invention shown in FIG. 2, the output signals of the comparators 100, 120, 130 are combined by a logic circuit 40 into a logic signal that determines the moment of ignition of the thyristor in time. tells whether it should be moved forward or backward. logic circuit 4
Instead of o, a number of analog switches are connected to the signal 55.65
．． 160, and with the output signal of the comparator controlled, select an appropriate one of the three signals 55, 65, and 230.
5, select one, control the signal accordingly so that it follows the output characteristics shown in FIG. 1 at any time, and supply that signal to the analog regulator circuit 30! to be accomplished. In this case, the selected signals, that is, the current signal 55, the voltage signal 65, and the instruction signal 160, can be controlled by comparing each of them with each reference voltage in an analog manner.

Configurations other than those described above may also be adopted based on the present invention.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the output characteristics of the IUW charging device according to the present invention in comparison with the characteristics of a known IUW charging device, FIG. 2 is a block diagram of the charging device according to the present invention, and FIG. 3 is a diagram showing the output characteristics of the IUW charging device according to the present invention. FIG. 4 is a diagram showing the output characteristics of the charging device in comparison with the characteristics of a known W charging device, and FIG. 4 is a diagram showing details of the converting device of FIG. 2 for generating an instruction signal. 3...Characteristics part, 1o...Storage battery, 20...
・Charging current source, 3o... fist control circuit, 40 good -φ network, 50,6G... output terminal, 55...
・Current signal, 65...Voltage signal, 70.8o-・Fist・Normalizing amplifier, 16o...Instruction signal. Patent applicant Inelco Einis

Claims (9)

[Claims] (1) In a lead-acid battery charging method in which the charging current decreases and the charging voltage increases above the charging voltage level at which bubble generation occurs, according to a generally linear characteristic, the charging current and charging voltage for each storage battery cell are The linear characteristic (3, 302) at a level above the bubble generation voltage level is approximately 0.5I_
5, it crosses the bubble generation voltage level at about 0.5
V/I_5 and 0. A method for charging a lead-acid battery, characterized by controlling the slope (a) to be between IV/I_5. (2) The slope (a) of the linear characteristic (3, 302) at a voltage level exceeding the bubble generation voltage level is approximately 0.2V/I_
5. The method according to claim 1, characterized in that: (3) According to a roughly linear characteristic, the charging current decreases and the charging voltage increases above the charging voltage level at which the bubble generation phenomenon occurs, and a controllable charging current source and a charging current proportional to the charging current a current sensor for forming a first signal proportional to the charging voltage, a voltage sensor for forming a second signal proportional to the charging voltage, and a control device connected to the plurality of sensors and the charging current source to control the charging process. In the lead-acid battery charging device, the control device is provided with at least one converter (70, 80, 150), whereby a first signal (50, 55) and a second signal (60, 65) are provided.
), the charging current and charging voltage have the above linear characteristics (3, 3
02), and at least one adjustment device (30, 40, 130) is provided, and the adjustment device converts the instruction signal (160) into a constant instruction signal (160) within a range that complies with The arrangement is configured to generate a regulation signal for the charging current source (20) by comparison with a reference signal (132), such that the charging current and charging voltage have a linear characteristic (3, 302) at any time. A lead-acid battery charging device characterized in that it is modified according to. (4) The conversion device (70, 80, 150) generates a weighted sum of the first signal (50, 55) and the second signal (60, 65), and an instruction signal (16
0, V_w), and the gradient (a) of the linear characteristic (3, 302) is determined approximately by the weight of the signal in the addition state. Apparatus according to paragraph 3. (5) A first voltage (263) proportional to the first signal (50, 55) is applied to the conversion device (70, 80, 150).
a first voltage generator (230, 260) for converting the second signal (60, 65) into a second voltage (230, 260) proportional to the second signal (60, 65);
253) and two resistors (R_1, R_2) are provided, and the two resistors are connected in series, and each resistor is connected between the two resistors. is connected to one of the voltages (253, 263) at a terminal remote from the connection point (290) of the regulator (30,
40, 130) is adapted to receive a voltage as an indication signal at the connection point (290) between the resistors (R_1, R_2). (6) providing the first voltage generator (230, 260) with an adjustment device (230) for adjusting a conversion factor between the first signal (50, 55) and the first voltage (263); According to claim 5, the adjusting device (230) is actuated to simultaneously adjust both the slope of the linear characteristic and the charging current for storage batteries of different capacities. Device. (7) The device according to claim 6, wherein the adjustment device (230) is arranged on the operation panel (10) so that manual operation can be performed. (8) Each voltage generator is configured with an operational amplifier (250, 260), a signal is supplied to the non-inverting input terminal (251, 261), and a voltage is supplied to the inverting input terminal (252, 260) of the operational amplifier (250, 260). Output terminal (253) connected to
, 263). (9) The first signal is a potentiometer (
the first voltage generator (26) via the contact lever of the first voltage generator (230);
9. The device according to claim 8, characterized in that the device is supplied to a non-inverting input terminal (261) of 0).