RU2477510C2 - Method for electrochemical current source (eccs) discharging - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: according to the method, ECCS discharging is carried out by way of periodical connection and disconnection of load and at constant power; in the course of discharging charge current increment rate is controlled. At current increment rate equal to zero the load is disconnected; with load disconnected, one controls ECCS voltage increment rate for the voltage final value recovery at constant rate.

EFFECT: electric discharge characteristics increase.

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Description

The invention relates to the field of electrical engineering, and in particular to methods of discharge ECCP.

Of the known methods for discharging ECCP according to the set of essential features and the achieved technical result, there is a method of pulsed discharge ECCP by periodically connecting and disconnecting a load (RF patent No. 2302060 C1, 2007).

A disadvantage of the known discharge method is the insufficiently high output electrical characteristics, which is associated with a non-optimal choice of the discharge mode.

The technical result of the invention is the creation of a discharge method ECHIT, providing improved electrical characteristics.

The specified technical result is achieved by the fact that the method of discharge of the ECC is carried out by periodically connecting and disconnecting the load, while the discharge is carried out at a constant power, moreover, during the discharge, the rate of rise of the discharge current is controlled and, at a rate of rise equal to zero, the load is disconnected; when the load is off, control the rate of increase in voltage of the ECC to its final value, provided the rate of rise is constant.

The indicated discharge mode makes it possible to remove significantly higher specific powers and energies from ECCP than with the known discharge regime due to the fact that the ECC current source is periodically connected and disconnected from the load through a key element, inductor, storage capacitor, and discharge power stabilizer. For a given load, the time of the state connected to the ECM is determined by the time the current reaches its maximum value and the exposure time until it decreases. When the current decreases, the ECC is disconnected from the load. During the on state, the ECC operates at a minimum internal resistance equal to the active component of the impedance, i.e. in the absence of a polarizing component. Thus, when the state is switched on, ECM gives off the maximum possible energy with its minimum internal resistance. When the state is off, the current through the ECM should be equal to zero, because otherwise, the constant-current background leads to the appearance of a polarizing component of the internal resistance of the ECC. The off-state time is determined by the time of restoration of the ECC voltage to the final one, provided that the slew rate is constant. Thus, the essence of the method of energy removal from ECT is to separate in time the selection of electrical energy from ECC from the actual redox chemical reaction that takes place in ECC, which is the source of the electromotive force of the latter. During the on state, an inductive electric energy storage device (inductor) with a power stabilizer provides a continuous increase in current with ECCP until it decreases. In this time interval, a chemical reaction does not occur. In the off state, the chemical reaction itself occurs in the absence of current.

The analysis of the prior art showed that the claimed combination of features of the invention is not known. This allows us to conclude that the claimed method meets the condition of "novelty."

To verify the conformity of the claimed invention with the criterion of "inventive step", an additional search was carried out for known technical solutions in order to identify features that match the distinctive features of the claimed technical solution from the prototype. Thus, we can conclude that the claimed technical solution does not follow explicitly from the prior art. Therefore, the claimed invention meets the criterion of "inventive step".

The invention is illustrated by drawings and an example implementation of the method.

Figure 1 presents the installation for the practical implementation of the claimed method.

Figure 2 shows the dependence of the removed power on the relative capacity of the battery for two modes of operation of ECE.

Figure 3 shows the dependence of the removed power on the relative capacity of the battery for two modes of operation of ECE.

Practical example

To implement the claimed method, an installation was assembled, which included ECT (1), a key element with a control unit (2), a choke (3), a storage capacitor (4), a discharge power stabilizer (5), a voltage and current meter, and the rate of change (6), the load (7) (see figure 1).

Example No. 1.

A lithium-ion battery manufactured by Kokam was tested, consisting of three series-connected SLPB 55205130 batteries with a voltage of 12.6 V and a capacity of 11 Ah. The battery was charged up to 12.6 V (4.2 V per battery) and discharged up to 8.1 V (2.7 per battery) in two modes.

Mode 1. The discharge was carried out at a constant resistance of 1.2 ohms.

Mode 2. An electronic device was connected to the same battery, which included a key element with a control unit, an inductive storage device, a storage capacitor, a discharge power stabilizer, a controller for measuring current, voltage, and slew rate, and a load was connected to the output of the electronic device. The load was selected so that at the output of the electronic device the power was equal to the initial discharge power in mode No. 1 with a constant resistance of 1.2 Ohms. The power was recorded both at the input and at the output of the electronic device. The energy sampling frequency ranged from 19 kHz to 0.25 kHz.

Figure 2 shows that in the discharge mode at constant resistance (curve 1), the initial discharge power equal to 125 W monotonously decreases depending on the degree of discharge of the battery to a value of 64 W, corresponding to a 95% degree of discharge. The power drop was 90%. In mode No. 2, the powers taken both at the output of the electronic device (curve 2) and at the input of the electronic device (curve 3) are independent of the degree of discharge of the battery and are 125 W and 135 W, respectively. The difference of 10 watts, equal to 135-125 watts, is lost in the electronic device itself. The total internal resistance in mode No. 1 was 12 mOhm, and in mode No. 2-4.5 mOhm, which is equal to the active component of the total internal resistance of the battery.

Example No. 2. The lead starter battery manufactured by Varta 12 V 40 Ah was tested. The battery was discharged in two modes to a final voltage of 10.2 V.

Mode 1. The battery was discharged at a constant resistance of 0.31 ohms to a voltage of 10.2 V.

Mode 2. The battery was discharged by connecting an electronic device that included a key element with a control unit, an inductive storage device, a storage capacitor, a discharge power stabilizer, and a controller for measuring current, voltage, and slew rate.

The load was selected so that at the output of the electronic device the power was equal to the initial discharge power in mode No. 2 with a constant resistance of 0.31 ohms. The power was recorded both at the input and at the output of the electronic device. The energy sampling frequency ranged from 19 kHz to 0.25 kHz.

Figure 3 shows that for mode No. 1 (curve 1), the power from the initial value of 502 W, corresponding to a fully charged battery, by the end of the discharge, corresponding to 52% of the discharge capacity, is 380 W, i.e. power drop was 32%. In the mode with the electronic device connected, the power taken at the output of the electronic device (curve 2) and at the input of the electronic device (curve 3) are independent of the degree of battery discharge and remain constant 502 W and 540 W, respectively. Moreover, the discharge capacity in mode No. 2 is 62%. The total internal resistance of the battery in mode No. 1, when discharged at a constant resistance of 0.31 Ohms, changed from the initial 16 mOhm to the final 22 mOhm. In mode No. 2 with an electronic device connected, from the initial 2 mOhm to the final 7 mOhm, which corresponds to the active component of the total internal resistance.

The above and examples of the practical implementation of the method show that this method can be implemented in practice. Therefore, the claimed method meets the criterion of "industrial applicability".

Claims (1)

A method for discharging an electrochemical current source (ECC) by periodically connecting and disconnecting a load, characterized in that the discharge is conducted at constant power, and the maximum energy taken from ECC is determined by the maximum time the ECC state is connected to the load, during which the controlled rate of rise of the discharge current is limited by a value equal to zero, and the minimum time of the disconnected state of the ECC from the load is the time of restoration of the ECC voltage to the final with a constant speed th increase.

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