RU2293343C1 - Method for determining remaining capacity of lead accumulator - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: preliminarily for appropriate type of accumulators an empiric formula is determined, determining dependency of full capacity of lead accumulator on discharge current I_dis, temperature t and electrolyte concentration d. On basis of individually measured during receiving-transferring tests of certain accumulator battery, values of capacitors in two discharge modes, determined are correction coefficients and precise values of full capacity, appropriate for discharge currents related to marked sub-ranges of current. During discharge, discharge vessel of accumulator battery is determined continuously, by integrating discharge current C_j,p = Σ(I_j,p·Δt), and each increment thereof is added to content of j-numbered cell, where j - number of sub-range, to which current discharge current I_jp is related. Computation of remaining capacity at present discharge current, related to n sub-range, is performed by modifying all discharge capacitors, received in various sub-ranges, to n sub-range, adding modified discharge capacitors and subtracting that total from precise value of full capacity, appropriate for n-numbered sub-range.

EFFECT: increased precision.

Description

The invention relates to electrical engineering, in particular to chemical current sources, and can be used to control the technical condition of, for example, lead-acid batteries.

A known method for determining the degree of charge of the battery (RU, patent 2110119 C1 H 01 M 10/48, G 01 R 31/36, 1998), which consists in measuring the equilibrium electromotive force (emf) of the battery on two electrodes, additionally introduced into the electrolyte . In addition, a temperature sensor is also introduced into the electrolyte, the temperature of the electrolyte is measured, the volume of the electrolyte, the nominal capacity of the battery, the equilibrium EMF of a fully charged battery are recorded, taking into account which the degree of charge of the battery is calculated, adjusting the result of calculations according to the temperature of the electrolyte.

The disadvantage of this method is that to determine the degree of charge requires the creation and use of additional technical means: electrodes, temperature sensors, electrolyte volume meters. Therefore, the device for implementing this method is complicated.

There is also a method of determining the residual capacity of a lead battery (prototype) (Dasoyan MA, Aguf I.A. The modern theory of a lead battery. - L .: Energy, 1975), which consists in the fact that previously for the corresponding type of battery according to the empirical formula determine its full capacity depending on the discharge current, temperature and electrolyte concentration.

During the operation of a lead battery (CA) of this type, when it is discharged with a constant current, the discharge current is integrated into the functions of time, thereby obtaining a discharge capacity, and then the residual capacity of the SA is determined as the difference between the total capacity and discharge capacity at this particular moment in time.

The main disadvantage of the method adopted for the prototype is its low accuracy. This is due to the fact that the total capacity of the SA and its dependence on the discharge current, temperature, and electrolyte concentration change over time. Each specific instance of CA has its own individual characteristics and some difference in its full capacity from the capacity corresponding to this type of CA. In addition, the calculation of the residual capacity as the difference between the full and discharge capacity can only be done if the entire discharge is produced by one constant current. In practice, under operating conditions, SAs are discharged most often by a current arbitrarily varying in time.

The objective of the present invention is to improve the accuracy of determining the residual capacity of the battery at any time of its discharge, regardless of the change in the discharge current in time, by taking into account the change in the characteristics of the battery in time, the individual characteristics of a particular battery, the possible shutdown of the lagging battery that limits the capacity of the battery when it becomes lagging during operation, another battery.

The essence of the invention lies in the fact that previously for the corresponding type of batteries an empirical formula is determined that establishes the dependence of the total capacity of a lead battery on the discharge current I _bit , temperature t and electrolyte concentration d.

The capacitance values in the two discharge modes, individually taken during acceptance tests of this particular storage battery (AB), are determined by the correction factors and the adjusted full capacitance values corresponding to the discharge currents related to the intended current sub-ranges. During the discharge, the discharge capacity of the battery C _{j, p is} continuously determined by integrating the discharge current C _{j, p} = ∑ (I _{j, p} · Δt), and each increment is summed with the contents of the j-th cell, where j is the number of the subband, to which the current discharge current I _{j, p} . The calculation of the residual capacitance at the current discharge current related to the nth subband is carried out by bringing all the discharge capacitances obtained in various sub-ranges to the nth subband, summing the reduced discharge capacities and subtracting this sum from the updated value of the total capacity corresponding to n- th subrange.

The method for determining the residual capacity of a lead battery is that previously, before starting operation, an empirical formula is determined for the corresponding type of battery, which establishes the dependence of the total capacity of a lead battery on the discharge current I _bit , temperature t, and electrolyte concentration d

and take values for capacities in two discharge modes, for example, C _{1, cprr} and C _{50, cprr} , respectively, in the 1 and 50-hour discharge mode, which are _individually determined for equation (1) for acceptance tests individually for a given storage battery ) and the corresponding discharge currents I _{1, CRR} and I _{50, CRR the} values of the full capacities C _{1, CRR, n} and C _{50, CRR, n} , correction factors for the individual characteristics of the battery

and the coefficients a _k and b _k in the equation K _j = a _k + b _k · I _{j the} dependence of the correction factors on the discharge current

a _k = K _{50, CRR} -b _k · I _{50, CRR}

по формуле (1)The range of possible discharge currents is divided into m subbands, setting the number of subband j in the order of increasing current, and the average values of currents I _{j, cp} in these subbands and the corresponding full capacity calculated values corresponding to these currents are calculated

by the formula (1)

correction factors

K _j = a _k + b _k · I _{j, Wed,}

as well as adjusted full capacity values

A column of m rows is formed (by the number of current sub-bands) for recording the values of the discharge capacity.

.During the discharge, the discharge capacity of the battery is continuously determined by integrating the discharge current C _{j, p} = ∑ (I _{j, p} · Δt), and each increment is summed with the contents of the j-th cell, where j is the number of the subband to which the current discharge current I _j , thus obtaining in each j-th cell the corresponding value of the discharge capacity

.

To calculate the residual capacitance at the current discharge current related to the nth subband, all discharge capacitances obtained in all jth subranges lead to the nth subband according to the formula

, для j=1, 2,...m.

, for j = 1, 2, ... m.

Here:

- приведенное значение j-ой разрядной емкости к n-ому поддиапазону;

- the reduced value of the j-th bit capacity to the n-th subband;

- коэффициенты приведения j-ых разрядных емкостей к n-ому поддиапазону, определяемые по формулам

are the coefficients of bringing the j-th capacitance to the n-th subband, determined by the formulas

;- for j = n

;

, (таким способом учитывается то, что при переходе с меньшего тока разряда на больший ток разрядная емкость (и, соответственно, остаточная емкость) уменьшается пропорционально полной емкости);- for j> n

, (in this way, it is taken into account that when switching from a lower discharge current to a higher current, the discharge capacity (and, accordingly, the residual capacity) decreases in proportion to the full capacity);

(таким способом учитывается то, что при переходе с большего тока разряда на меньший ток разрядная емкость, не изменяясь, вычитается из соответствующей полной емкости, а остаточная емкость при этом немного (до 5%) уменьшается).- for j <n

(In this way, it is taken into account that when switching from a larger discharge current to a lower current, the discharge capacity, without changing, is subtracted from the corresponding full capacity, while the residual capacity decreases slightly (up to 5%)).

The residual capacity is determined by the formula

The residual capacitance is calculated similarly for any other current value related to the k-th subband.

по поддиапазонам. Для этого рассчитывают поправочный коэффициентIn the case of a full battery discharge, i.e. its shutdown in connection with the achievement of the final discharge voltage on the lagging battery, adjust all the calculated values of the full capacity

by subbands. To do this, calculate the correction factor

where j is the number of the current subrange;

n is the number of the subband in which the last discharge current was located.

по поддиапазонам разрядных токов и новые значения

сохраняют до следующего полного разряда АБ.This coefficient multiplies all the values of the total discharge capacity

by sub-ranges of discharge currents and new values

save until the next full discharge AB.

по поддиапазонам разрядных токов.If lagging batteries are excluded from the battery during battery operation, the remaining batteries determine the number of the other battery with the lowest voltage, which limits the battery capacity. For this new lagging battery, when the discharge is brought to the final discharge voltage, all values of the total discharge capacity are similarly specified

on subbands of discharge currents.

Thus, according to the proposed method, the calculation of the residual capacity can be performed for any changes in the discharge current in time and, in addition, when calculating the residual capacity, the change in the characteristics of the battery over time, the individual features of a specific battery, and the possible shutdown of the lagging battery that limits the capacity of the battery when lagging during operation, another battery becomes. All this helps to increase the accuracy of determining the residual capacity of the battery.

Claims (1)

The method for determining the residual capacity of a lead battery, which consists in the fact that prior to starting operation for an appropriate type of battery, an empirical formula is determined that determines the dependence of the total capacity of a lead battery on the discharge current I _bit , temperature t and electrolyte concentration d

characterized in that during the acceptance tests of this particular battery, the capacitance values are individually taken in two discharge modes, for example, C _{1, crr} and C _{50, crr} , respectively, in the 1 and 50-hour discharge mode, is determined by equation (1) and the corresponding currents discharge I _{1, chr} and I _{50, chr the} values of the full capacities C _{1, hrr, n} and C _{50, hrr, n} , correction factors for the individual characteristics of the battery

and the coefficients a _k and b _k in the equation K _j = a _k + b _k · I _{j the} dependence of the correction factors on the discharge current

a _k = K _{50, CRR} -b _k · I _{50, CRR} divide the range of possible discharge currents into m subbands, setting the number of subband j in the order of increasing current, and calculate the average values of currents I _{j, cp} in these subbands and the corresponding values of the calculated total capacitance

by the formula (1)

correction factors K _j = a _k + b _k I _{j, cp} , as well as adjusted full capacity values

form a column of m rows (according to the number of current subranges) into which discharge capacities are recorded during the discharge, continuously determined by integrating the discharge current C _{j, p} = Σ (I _{j, p} · Δt), and summing each increment with the contents j -th cell, where j is the number of the subband to which the current discharge current I _{j, p} belongs, thus obtaining, in each j-th cell, the corresponding value of the discharge capacity

, lead all the discharge capacitance obtained in different sub-bands to the nth sub-band according to the formula

, for j = 1, 2, ... m, Where

- the reduced value of the j-th bit capacity to the n-th subband;

are the coefficients of reduction of jx discharge capacitances to the nth subband, determined by the formulas for j = n

; for j> n

; for j <n

, summarize all the discharge capacitances reduced to the nth subband and calculate the residual capacity corresponding to the discharge current related to the nth subband according to the formula

correct all calculated full capacity values

by subbands when the battery is completely discharged, i.e. when it is turned off due to the achievement of the final discharge voltage on the lagging battery, by calculating the correction factor

where j is the number of the current subrange; n is the number of the subband in which the last discharge current was; multiplying by this coefficient all specified values of the full discharge capacity

on subbands of discharge currents and saving new values

until the next full discharge of the battery.