RU2461014C1 - Potentiostatic method for identification of accumulators with lower capacity within nickel-cadmium accumulator battery - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: method may be used with accumulators while in continuous float charge mode (buffer mode). The substance consists in the following: charging voltage exceeding the current charging voltage by 0.05-0.50 V is supplied to the fully charged accumulator battery during 30-90 sec. Steady-state voltages on each accumulator within the battery are recorded and compared. The accumulator with the highest charging voltage has the lowest capacity.

EFFECT: diagnostics simplification without disconnection from the consumer.

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Description

The invention relates to electrical engineering, and in particular to methods for diagnosing chemical current sources.

It is known that the most low-quality battery limits the capacity of the entire battery. To restore the battery capacity, you must either replace a low-quality battery with a new one, or restore the capacity of a low-quality battery using special methods.

A known method for determining the health of a Nickel-cadmium battery (application No. 93021762/07, G01R 31/36 from 04/26/1993) by measuring current and voltage during its operation. According to the results of measuring the charging and discharge characteristics, the parameters of the mathematical models of the batteries are determined and the working capacity and residual capacity are evaluated. However, the implementation of this method requires several hours, quick operational control is impossible.

The closest in technical essence is a method for identifying batteries with the smallest capacity for unsealed batteries of nickel-cadmium batteries (positive decision on the application No. 2009117037/28 (023401) dated 05/05/2009), according to which a charging voltage of 0 is applied to each battery 05-0.50 V, exceeding the open circuit voltage (NRC) or the charging buffer voltage, and then compare the charging currents of the batteries.

However, this method is difficult for use in batteries used as uninterruptible power supply, since for measuring current it is necessary to break the electric circuit to turn on the ammeter. In addition, at the time of connecting the ammeter and measuring current, the uninterruptible power supply ceases to fulfill its functional purpose - it is no longer an uninterruptible source.

The authors were faced with the task of simplifying the diagnostics of the state of individual non-sealed nickel-cadmium batteries collected in a battery, without even briefly disconnecting them from the battery and the consumer. This problem is solved in that a potentiostatic charging voltage of 0.05-0.50 V, exceeding the charging buffer voltage, is applied to a fully charged battery for a short time during 30-90 s, and the steady-state voltage of the closed circuit (NSC) is measured on each battery. After that, a comparison is made of the steady-state values of the NSC. Batteries with the highest NZC values will have the lowest capacity and limit the capacity of the entire battery.

A distinctive feature of the method is that the diagnostics are carried out on a battery that is in a fully charged state. Such a diagnostic method is much easier to implement in practice in real conditions, since it is technically easier to measure voltage than current, and you do not need to disconnect consumers from the SBE, break the circuit and turn on the ammeter to measure current.

Assessing the condition of batteries is important for batteries that have been used for many years as a constant-current power source in uninterruptible power supply systems (SBE) and under constant recharging in a buffer mode. Our proposed method allows us to quickly, almost within a minute, find batteries with reduced capacity, without disconnecting the battery from the SBE, and if necessary, conduct preventive measures in time.

A battery of 10 leaky nickel-cadmium batteries SLP 12 from SAFT, which were located at the facilities of Astrakhangazprom LLC and operated for more than twenty years in a buffer mode at a voltage of 1.40 V per one battery, was diagnosed. At the beginning of operation, the batteries had a nominal capacity of 120 Ah; after 20 years of operation, their capacity decreased to 10-50 Ah. After the buffer charge, the potentiostatic charging voltage of 14.5 V was applied immediately to the battery, i.e., 0.50 V higher than the buffer charging voltage, and the SCC values of each battery were measured 40 seconds after the start of charging. The measurement results are presented in the table. After that, the voltages of each battery were compared.

Battery No. one 2 3 four 5 6 7 8 9 10 NZC battery with a potentiostatic charge of 14.5 V 1,408 1,406 1,410 1,408 1,390 1,387 1,385 1,383 1,398 1,382 Discharge capacity, Ah 12 fourteen fourteen 12 16 22 25 33 22 40

It was found that 4 batteries with a discharge capacity of 12-14 Ah had an SC in the range of 1.408-1.410 B. For batteries with a discharge capacity of 22 to 40 Ah, the values of the SC were in the range of 1.381-1.398 B.

In this way, the batteries No. 1 and No. 2 having the highest charging voltage were detected in the storage battery, and the batteries with the lowest capacity corresponded to them. The time spent on the diagnosis was less than a minute. With this method, it is possible to diagnose batteries with any number of batteries without disconnecting them from operating production equipment and other consumers.

When the diagnostic time is less than 30 s, unreliable results can be obtained, and more than 90 s, the efficiency of the method is lost.

Thus, our proposed method allows us to quickly, without disconnecting from consumers, identify batteries with the smallest capacity in a battery of leaky nickel-cadmium batteries. This method is especially convenient when identifying batteries with the smallest capacity in the batteries of standby current sources (SBE).

The proposed method was tested in the pilot production of NPP VNIKO LLC in the SBE system. He showed efficiency and reliability. It is supposed to be introduced at the enterprises of the fuel and energy complex.

The patent information search allows us to judge the novelty, industrial applicability and inventive step of the proposed method. We believe that the “Potentiostatic method for detecting batteries with the smallest capacity for unsealed nickel-cadmium batteries” described by us can be recognized as an invention and is protected by the patent of the Russian Federation.

Claims (1)

Potentiostatic method for detecting batteries with the smallest capacity for non-sealed nickel-cadmium batteries, which consists in supplying the battery with a charging voltage that is 0.05-0.50 V higher than the current charging voltage for 30-90 s, followed by analysis of the responses, characterized in that the voltage is supplied to a fully charged battery, the charging voltages established on each battery are recorded and compared with each other.