RU2329572C1 - Method of operation of nickel-hydrogen accumulator battery - Google Patents

Abstract

FIELD: electric engineering.

SUBSTANCE: invention may be used in production and ground operation of nickel-hydrogen accumulator batteries. According to invention method of operation of nickel-hydrogen accumulator battery consists in conduction of charges and discharges with active thermostating and monitoring of accumulators temperature, and storage in charged or discharged condition without performance of active thermostating. On completion of accumulator battery charge or discharge, prior to storage, its thermostating is continued, at that monitored temperature is differentiated in time dT/dτ, and thermostating is stopped after achievement of dT/dτ of established negative value, besides, thermostating of accumulator battery prior to storage is continued at least for 1.5 hour on completion of charge or discharge.

EFFECT: increase of reliability and preservation of resource characteristics.

2 dwg

Description

The invention relates to the electrical industry and can be used in the manufacture and ground operation of Nickel-hydrogen batteries.

In the process of manufacturing and ground-based operation of the battery, there are periods of storage both in a charged and in a discharged state.

A feature of nickel-hydrogen storage batteries is that during the transition from the charge or discharge mode to the storage mode, the electrochemical processes in the batteries do not stop and their intensity decreases only after some time has passed. Such processes include the recombination of oxygen, which is partially released in the final phases of charge and discharge, with hydrogen and the constantly present process of self-discharge of batteries.

Known methods of operating nickel-hydrogen storage batteries (see chapter X1, B.I. Tsenter, N.Yu. Lyzlov "Metal-hydrogen electric systems." L .: Chemistry, Leningrad Branch, 1989 [1]).

The disadvantage of these methods is that issues of thermostating of batteries during their operation by known methods are not considered.

The closest technical solution is the method of operating the battery as part of the spacecraft, providing for its active thermostating (see RF patent No. 2164881) with a temperature control system with hydraulic circuits during operation (including ground operation) of the battery, adopted as a prototype.

The disadvantage of this method is that during the transition from cycling the battery to its storage, the temperature control mode is not defined, which in terrestrial conditions leads to unjustified consumption of the battery itself and the temperature control system, if the process of electric tests of the spacecraft is organized as a continuous process, or fraught with local overheating of the batteries, if there are interruptions in operation (with the shutdown of the power supply system of the spacecraft and the temperature control system), it reduces the reliability of the battery operation.

The aim of the invention is to increase the reliability of operation and preservation of the resource characteristics of a nickel-hydrogen storage battery.

This goal is achieved by the fact that at the end of the charge or discharge of the battery before storage, thermostatting is continued, and thermostatting is stopped after the electrochemical processes associated with the recombination of the released oxygen and hydrogen are completed in the batteries, while the controlled temperature is differentiated in time dT / dτ, and stopped temperature control after reaching dT / dτ steady-state negative value, in addition, temperature control of the battery before storage They last at least 1.5 hours from the end of the charge or discharge.

Indeed, during the ground operation of 28NV60 nickel-hydrogen storage batteries, developed by Saturn OJSC, Krasnodar, thermostating of which was carried out by blowing, with a given gas flow rate, the following was recorded.

After the battery charge was turned off at the upper charge level, its thermostating was stopped, while the temperature of the batteries exceeded the temperature of the cooling gas (ambient temperature) by (5-7) ° С. After 10-12 hours of storage without active temperature control, the temperature of the batteries was recorded, which exceeds the ambient temperature by (15-20) ° С. It was revealed that a similar tendency in the temperature increase of the batteries is characteristic of the battery even after its discharge.

A similar phenomenon was recorded during the ground operation of a 40NV70 battery with a liquid thermostat circuit, the same developer and manufacturer.

The revealed fact leads to local overheating of the batteries and, therefore, contributes to such negative phenomena as temperature deformation, corrosion of the active mass, redistribution of the electrolyte concentration (increase in internal electrical resistance), which reduces the reliability of operation and degrades (decreases) the resource characteristics of a nickel-hydrogen battery. It is also known that the rate of chemical reactions in the battery in the range of (0-50) ° C with an increase in temperature for every 10 ° C increases by about 2 times, including undesirable reactions.

Figure 1 presents graphs of changes in temperature of the batteries of the rechargeable battery, after the end of its charge (discharge), in time (T) and the differential of this characteristic in time (dT / dτ).

Consider the characteristic sections of these graphs. Section “a-b” corresponds to the heat dissipation level in the battery that exceeds the heat removal level, section “b-c” corresponds to the heat dissipation level in the battery which is lower in value of the heat removal level, sections “cd” and “de” correspond to the lack of heat generation in the battery - here goes simple removal of stored heat. At the same time, the heat emission from the constantly present self-discharge of the batteries in the last two sections of the graphs is insignificant, which allows them to be neglected.

It should be noted that the process of interaction of oxygen with hydrogen evolved can take a relatively long time, however, with effective heat removal time of 40-60 minutes is enough to complete the process in full. Further, time is needed to “remove” the accumulated heat from the batteries. The efficiency of removing the accumulated heat depends both on the design of the batteries (thermal conductivity from the electrode block to the battery housing) and on the performance of the thermostatic system. In any case, the performance of the temperature control system is calculated from the condition of heat removal of the maximum calculated value of the heat emission of the battery. Based on this premise, it is possible to significantly simplify the method of operation by defining a simple time criterion for the time of temperature control during subsequent storage.

The analysis of the nature of the change in temperature of the batteries after the end of the charge or discharge on various modifications of nickel-hydrogen batteries under active temperature control showed that the output to the linear section of temperature reduction (adequate to the plot "cd" of the graph of figure 1) occurs after 30 minutes to 1 hours 10 minutes. Taking into account the technological reserve, the time of the subsequent thermostating (after the end of the charge or discharge) is selected as “not less than 1.5 hours”.

Figure 2 presents the structural diagram of the workplace for autonomous work with rechargeable batteries in ground conditions.

The workplace contains:

- a charge-discharge complex consisting of a charge-discharge device, a battery monitoring device and an interface expansion device;

- control devices for analogue pressure and temperature sensors;

- PC;

- a liquid-cooled protective thermostatic chamber to house the battery.

During ground operation, the battery is periodically stored in a charged or discharged state.

In order to preserve the resource, the battery is stored mainly in a discharged state, for which it is discharged before storage.

When resuming work, the battery is pre-charged.

In the process of discharging, charging and operating in a charged state, the battery is thermostated (in this example, by pumping coolant).

Since the workstation for autonomous work with rechargeable batteries is equipped with a PC connected to the “Device for monitoring analog pressure and temperature sensors” and through the “interface expansion device” with the “Charger-discharge device” and “Battery monitoring device”, the task of automatic determination the moment when the temperature control of the battery can be stopped (by a steady negative value dτ / dτ or by time - at least 1.5 hours) is solved by simple software.

The onset of the moment, allowing the termination of temperature control, can be displayed on the monitor screen in the form of a directive (with or without an audio signal) for subsequent execution by maintenance personnel.

Thus, the proposed method eliminates the occurrence of local overheating of the batteries, and therefore, reduces such negative phenomena as temperature deformation, corrosion of the active mass, redistribution of the electrolyte concentration, which increases the reliability of operation and preserves the resource characteristics of a nickel-hydrogen storage battery.

Claims (2)

1. The method of operation of the Nickel-hydrogen battery, which consists in carrying out charges and discharges with active temperature control and temperature control of the batteries and storage in a charged or discharged state without active temperature control, characterized in that upon termination of the charge or discharge of the battery before storage, thermostating it continue, differentiate the controlled temperature in time dT / dτ, and stop thermostating after reaching dT / dτ steady-state negative lnl value. 2. The method according to claim 1, characterized in that the thermostating of the battery before storage continues for at least 1.5 hours from the end of the charge or discharge.

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