SU1718305A1 - Method of measurement of residual capacitance of chemical current supply - Google Patents

Abstract

The invention relates to the electrical industry and can be used in the manufacture and operation of chemical current sources to measure their residual capacity. The aim of the invention is to reduce the duration and intensity of the measurement process. To measure the residual capacitance of the test source, a single rectangular positive charge pulse of a constant voltage equal to (1.0 ... 1.5) irc is fed to it, where U is r.c. the open-circuit voltage of the test source, with a duration of -10, measures the steady-state current during the measuring pulse, and the residual capacitance is determined by the function of the residual capacitance pre-installed for a given type of chemical current source and the constant current wives 4 il .. (L S

Description

The invention relates to the electrical industry and can be used in the manufacture and operation of chemical current sources (HIT).

A known method for determining the degree of charge of a battery is: by charging it with a pulsating current, measuring the ripple voltage of the alternating component of the charge current on it, comparing the measured value with the experimental graph and estimating the degree of charge of the battery pulsation voltage variable charge component

current on the degree of charge of the battery (1). The disadvantage of this method lies in the complexity of its implementation, since it is necessary to generate a pulsating charging current and to measure the voltage of the pulsations of the variable component of the charging current.

The closest in technical essence to the proposed method is a prototype adopted and implemented in a device for controlling the residual capacity of a galvanic cell, according to which a single positive charge pulse is formed and fed to the test cell.

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voltages exceeding the emf of the test element are then measured for the total duration of the distorted pulse, and judging by this feature the residual capacity of the test sample 2 is judged. The disadvantages of this method include the relatively large duration of the measuring process, including the duration of the measuring pulse and the duration distortions of this pulse, which appear as a result of transients; The process is relatively energy intensive due to the need for power supply, for example, a generator of frequency-controlled high-precision oscillations, devices for isolating the full duration of a distorted pulse, and other auxiliary processes.

The purpose of the invention is to reduce the duration and intensity of the measuring process.

The goal is achieved by the method of controlling the residual capacitance of a galvanic cell by forming and supplying unipolar positive pulses to it, exceeding the open circuit voltage of the monitored source, measuring the total duration of the distorted measuring pulse and estimating the magnitude of the distortion of the measuring pulse the residual capacity is supplied to the controlled source of a single rectangular shape of a pulse of constant voltage equal to (1.0 ... 1.5) Cr., where ur.ts. - the open-circuit voltage of the test source, with a duration of 10, measures the steady-state value of the current during the measuring pulse, and the residual capacitance is determined by the function of the residual capacitance of the constant current during the measuring pulse established for this type of HIT wives .

The proposed technical solution differs from the prototype in that the duration of the measuring pulse is set to from 103 s, the magnitude (amplitude) of the constant voltage is set to (1.0 ... 1.5) Up.q ., measure the steady-state value of the charge current during the measuring pulse, and the residual capacity of the test source is determined by the function of the residual capacity pre-established for this type of HIT, depending on the steady-state value of the current during the measuring charge pulse worth the voltage.

This difference allows us to conclude that the proposed technical solution meets the criterion of novelty.

Signs that distinguish the proposed technical solution from the prototype have not been identified in other technical solutions when studying the above-mentioned and related engineering areas and, therefore, provide for the proposed solution that the criterion meets significant differences.

It is known thatTenkovtsev VV, Tsentr B.I. Fundamentals of the theory and operation of sealed nickel-cadmium batteries .- L .: Energoatomizdat. Leningrad Department, 1985-96, p. 52.53) as the battery is charged under constant voltage, the charge current decreases (p. 531, fig. 185). Therefore, each level of a charged ™ test chemical source of current corresponds to a specific value of charge current. In the proposed method used this property.

In order to implement the method, a single short-term rectangular charging voltage pulse is applied to the test cell or battery of cells.

The simplest functional electrical circuit of the method is shown in FIG. Here, the resistor R is used to set the desired value of the voltage of the charging pulse measured by the voltmeter pV. The ammeter pA serves to measure the steady-state value of the charging current through the source under test during a measuring pulse of a constant voltage, and the switch S1 closes and opens the electrical circuit, forming a predetermined duration of the measuring pulse.

When a positive DC voltage is applied to the test source, the charging current does not instantly reach a steady, i.e. steady-state, values, and after some time, corresponding to the duration of transient processes, the duration of which in the HIT of different types reach tens and hundreds of seconds (3, p. 150). In fuel cells, the transient process is, for example, s, and in current sources with free liquid electrolyte, it lasts about 100 s (3, p. 152). For electrode processes in the solid phase, the transient time increases (3, p. 152).

The duration of the voltage pulse applied to the HIT for measuring a steady-state current value must exceed the duration of the transient of the tested HIT sample in order to

a steady state electrochemical mode was established at which the steady state charge current was measured. On this basis, in the proposed method, the practical duration of the voltage pulse applied to the test sample is set within 10 -103 s. These limits of the duration of the charging pulse cover the practical response time of the measuring means and the practical limits of the duration of transient processes in the HIT. For specific types of HIT, a specific pulse duration is recommended, for example, for nickel-cadmium batteries, it is in the range of 1-10 s.

Thus, according to the proposed method, a test of the source being tested is carried out by a single rectangular positive polarity by a short pulse of constant voltage with a duration of 10 3-103 s.

The measuring charge pulse is set to be rectangular in shape in order to obtain the same initial conditions for the occurrence of transients during each measurement and, therefore, most reliably provide the same stationary electrochemical charging process at the source, which ensures measurement accuracy. A single pulse excludes recharge of the source in case of its full charge, and most importantly, it saves energy in the measurement,

The service life of the tested sources in the proposed method is taken into account by changing the value of the DC voltage of the measuring pulse, i.e. by changing the amplitude of the measuring pulse.

It is known that the charge voltage of secondary HIT is expressed by the equation

I3 EEDs + En + Vo.s. b,

where E is EMF (open circuit voltage); . En - emf polarization;

Goz. - ohmic resistance at charge;

h - charge current (figure 2).

To charge with LU const, the condition Uuu.n must be met. S: Us. where Us is the source voltage of the source corresponding to the given level of charge of the female; ii. .- measuring pulse amplitude. So the lower limit of the amplitude of the measuring pulse UH. H. - Up.c. determined by the condition of charge.

It is known that as the products are in service, irreversible processes of lattice corrosion, crystallization of lead sulfate 5, sulfation, etc. occur in the active masses of electrodes. Aging processes cause a decrease in the open circuit voltage and a decrease in electrical conductivity, i.e. increase in ohmic resistance. These processes and cause a decrease in the discharge capacity. According to the proposed method, freshly prepared samples are tested at an amplitude of the measuring pulse equal to 1.5 ir. C. . For specimens made of veins, the value practically does not affect the value of the steady-state current value during the measuring pulse. As the resource is exhausted, the magnitude of the measuring pulse decreases, as it approaches, when the warranty period of service is exhausted to the actual voltage of the open circuit of the test source.

The significant influence of the temperature of the environment on the discharge capacitance of a HIT is known. In the proposed method, the effect of temperature is taken into account by known methods /, for example, by means of temperature coefficients of capacitance. The functional dependence of the residual capacitance on the magnitude of the established value of the current during the measuring pulse can be set for any temperature. In the implementation of the proposed method

5 at this temperature there is no need to take into account the temperature correction. If the method is carried out at a temperature different from the temperature of the functional dependence, the result obtained

0 is recalculated for temperature correction.

The inventive method was carried out when measuring the residual capacity of accumulator-batteries ZNKG-10D and galvanic

5 elements of type 373.

Construction of experimental functional dependence of the residual capacity of the ZIKG-UD batteries and elements 373 on the steady-state value of the charging current

0 when exposed to a single voltage pulse of a constant voltage conducted by the following method.

The following equipment was used for the tests: analog-computing

5 complex AVK-32, head. No. 43, edition 1982; 1 stabilized source of constant voltage type BSP-5, head. No. 894; oscilloscope type SV-17 head. No. 9113; millivoltmeter magnetoelectronic system type

MBA-47/5, head. Mg 16908; laboratory rheostats of type RSP-4, RPS-5, RSP-3.

To prepare the samples for the experiment, the 3KG-10D batteries were charged with direct current 1A for 15 hours. Then these batteries were discharged with direct current 1A first for 1 hour, second for 3 hours, etc. Galvanic cells 373 were discharged with a current of 300 mA.

A single charge pulse with a duration of 2 was applied from a constant voltage of 5V to a ZNKG-YDU battery and 2B to an element 373, and the steady-state value of the charging current was measured during this pulse. A ZNG-UD battery was discharged with a current of 2A, and a 373 cell was discharged with a current of 300 mA. To determine the residual capacity, the formula

QOCT Ip. tp,

where p is the discharge current;

tp is the duration of the bit.

The discharge was carried out up to the final discharge voltage of the voltage. The ZNKG – UD batteries were 2.7V, and the cell 373-1. The established value of the charging current was measured with an oscilloscope and millivoltmeter. The form of the charge current during the action on the battery and the unit of a single charge pulse of constant voltage is almost rectangular.

The experimental dependence of the residual capacity of the ZNKG-E battery and type 373 cell on the steady-state value of the charging current of the measuring pulse is shown in FIG.

The experimental relationship obtained according to the method described was used to measure the residual capacity of other samples of ZNKG-UD batteries and 373 cells. To do this, a 2-second pulse of a constant voltage of 5V was applied to a sample of an ZNGG-UD battery, and The steady-state current value during the measurement charge pulse was measured, and the residual capacitance was measured for the ZNKG-EED batteries and type 373 cells as measured by the currents. After this, the ZNKG – UD batteries were discharged continuously with current 1A to a voltage of 2.7 V, and cells of the type 373 were discharged to voltage 1 and the residual capacity was estimated using the classical method as the product of the obtained current and time values.

In the nine tests, the maximum error for the proposed method for ZNKG-ECD batteries compared to the classical continuous-discharge battery was 8.5%, and for elements of the 373 type - 6.7%,

The technical and economic efficiency of the proposed method consists in reducing the duration and power consumption of the measuring process and can be estimated as follows. In the prototype method, the duration of the measuring process includes the duration of the measuring pulse itself and the duration of the distortion of the measuring pulse.

(transient) caused by an appropriate level of charge of the test sample. In the prototype method, the duration of the measurement process Tpi is equal to

.f T and.i. + T pp

where Ti.i. - the duration of the measuring pulse in the method prototype;

g ppt - the duration of the distortion of the measuring pulse caused by transients (figure 4).

Unlike the prototype of the proposed method, the steady-state value of the charging current is measured during a measuring pulse. The duration of the measuring voltage pulse and the transient oscillations of the current over time are combined, therefore, the duration

measuring process ty. uniquely determined by the duration of the measuring pulse Hz.p.

The difference in the duration of the measurement process is

-. . .

l - -

At- Tip.p. –Tts.p.- Tj, i.n. Ti.i.

In case of equality Ti tii measuring pulses in the prototype method in the proposed method, the difference is

A t t ppt

I way, reducing the duration of the measuring process in the proposed method is equal to the duration of transients. If it is accepted that the minimum duration of the measuring pulses is equal to the duration of the transient process, then the reduction in the duration of the measurement process in the proposed method is halved compared to the prototype.

The reduction of the energy intensity of the proposed method in comparison with the prototype is achieved due to the fact that the implementation of the proposed method does not require electricity to generate pulses of the reference frequency and their subsequent conversion.

Ph o m u l a and v o v r i v i A method of measuring the residual capacity of a chemical current source (HIT) by forming and supplying it with single-pole positive pulses that exceed the open-circuit voltage of the monitored source, measuring the dependence of the current on time during the measuring pulse and the evaluation of the measured parameter and the previously established reference dependence of the residual capacitance of the HIT, characterized in that, in order to reduce the duration and intensity of the measuring process,

Sf

five

single rectangular pulse of constant voltage equal to (1.0 ... 1.5) Up.c., where Up.ii. The open-circuit voltage of the test source, with a duration of 10–3–103 s, is measured by setting the current value during the measuring pulse, and the residual capacitance is determined by the reference current dependence of the residual capacity preset for this type of HIT. voltage, and the amplitude of the measuring signal is chosen equal to the amplitude of the signal used, and the receipt of the reference dependence.

V

Ld / vi

/

tu.u.

Fig. /

AO50100 / 50200mA

Installed value of the charge / pitch of the measuring voltage pulse

Fig.Z

FIG. 2

 7- j. .u

L ti.U.P.

T

 / U

. l

4ZT l- + TP, p-TVV

FIG. four

TG

 / Yat

. l

th

Claims (1)

Claim A method for measuring the residual capacity of a chemical current source (CIT) by generating and supplying it with unipolar positive pulses exceeding the open circuit voltage of the controlled source, measuring the current versus time during a measuring pulse, and evaluating the parameter and the previously established reference dependence of the residual HIT capacities, characterized in that, in order to reduce the duration and energy-15 capacitance of the measuring process, a single rectangular pulse is supplied yannogo voltage of (1.0 ... 1.5) 11r.ts. where Up.q. - the open circuit voltage of the test source, with a duration of 10 ³ -10 ³ s, measure the steady-state current value during the measuring pulse, and the residual capacity is determined by the reference dependence of the residual capacitance on the steady-state current value during the measuring voltage pulse pre-set for this type of HIT, moreover, the amplitude of the measuring signal is chosen equal to the amplitude of the signal used when obtaining the reference dependence. FIG. 2 Fi g / A Ί first _{paragraph. t} ⁴ ost 0 50/00/50 200 mA Steady-state value of a charging current of a measuring pulse of a direct voltage Fig. 3 l / · - 7 ”- Τ ¹ 4. Τ! - Τ ^{11 t} 'Un' ⁱ Un ~ ^ί 'U (J ^C 7) .n ~ <(/, (/ Fig.Λ