RU2329582C2 - Method of accumulators charge with their grouping in system by principle of capacities division - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: method of accumulators charge with their grouping in the system by principle of capacities division is characterised by the fact that accumulators are divided into groups that include single-type and close in value of their measured capacity accumulators, with equal number of serially connected accumulators in different groups. Groups are charges simultaneously and in parallel, from the same source that generates charging current, which is determined as sum of currents that are dependent on measured capacity of accumulators in groups.

EFFECT: increase of charging process efficiency by more than 10-15%.

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Description

The invention is used in electrical engineering for charging accumulators and batteries from a charger as part of a charging network of the type 362614. In this case, the batteries are assembled into a system according to the principle of separation of capacities and charged with currents corresponding to the measured battery capacity, and the system as a whole is the sum of these currents. The technical result of the invention is to increase the efficiency of the charging process, increasing the efficiency of using the charging network by increasing the load factor of the charger in terms of power and by increasing the percentage of simultaneity in charging the batteries served by this charger.

The invention relates to electrical engineering, methods for charging batteries.

In the practice of operating charging networks, the same type of batteries and batteries are charged in groups from standard rectifier units that maintain a set current with stability of ± 10%, for example, VAKZ-1-40.

Maintenance-free batteries according to their technical description and operating instructions, for example, nickel-cadmium [Batteries and batteries, alkaline nickel-cadmium and nickel-iron. Technical description and operating instructions 0.358.011TO1], may differ in average capacity by 20% or more.

Known methods and devices to improve energy efficiency and reliability of the charging process with the specified variation in the parameters of the batteries being serviced when charging groups of batteries.

One of the solutions [Russian Federation Patent RU 2156533, 04/29/1999] is the leveling of the voltage imbalance on interconnected battery cells or batteries; moreover, the energy of imbalance is redistributed using one transformer between all cells or batteries. The accuracy of voltage leveling between cells depends on the identity of the parameters of the alignment circuits. The number of series-connected elements can reach 30.

The disadvantages of the method are the dependence of the energy efficiency of the charging process on the spread of the initial parameters of the rechargeable batteries and the influence of the intrinsic nonlinearities of the elements of the equalization circuit (transformer, diode, capacitor) on the charging current corresponding to the nonlinearity of the "normal mode" of the batteries [Batteries and batteries alkaline nickel-cadmium and nickel - iron. Technical description and operating instructions 0.358.011TO]. As a prototype, the system [Russian Federation Patent RU 2134477, 12/26/1996] for the automated charging of a large number of rechargeable batteries containing M modules with power sources was selected; N distribution and switching units, the number of which depends on the total number of charging cells; L charge-discharge channels with the function of a charger, including a charging cell with a connected battery in it. The modules are combined by a common highway of addresses and data from the host computer, equipped with special software that automatically monitors and controls the process of charging / discharging batteries by analyzing their measured electrical characteristics (current and voltage), making decisions about changing the charging / discharging mode and issuing commands about changing the mode, as well as presenting the received data in a user-friendly form.

Such a charging system is complex and cumbersome. The charging process in it is inefficient due to the large number of charger elements included in the charging current circuit of an individual battery or battery, and the control program does not measure or analyze the actual battery capacity as its electrochemical characteristic.

The problem solved by the proposed method is to maintain the electrical characteristics and reliability of rechargeable batteries and batteries charged by groups and which may have different (up to 20% or more) values of the measured electric capacity.

The problem is solved by arranging rechargeable batteries and batteries in a system according to the principle of separation of capacities. For this, rechargeable batteries or batteries are divided into groups that include batteries or batteries of the same type and similar in value to their measured capacity; with an equal number of series-connected batteries in different groups. Charging groups of batteries is carried out simultaneously and in parallel, as a system, from a single source or charger, forming a system charging current, defined as the sum of the currents in the groups. The current in the group is defined as dependent on the measured capacity of the batteries in the group.

The layout of the batteries in the system according to the principle of separation of capacities allows you to use the redistribution of the system current between groups of batteries to equalize the voltage in the groups, and the redistribution of voltages within the groups to align the process in time, to its completion.

Using the proposed method improves the efficiency of the charging process, which is expressed in the possibility of:

- reduction by up to 10% of the voltage imbalance on the series-connected batteries by reducing their diversity;

- include batteries of one type close in capacity in one group of the system, and batteries of another type close in capacity in another group, provided that all simultaneously charged batteries belong to the same electrochemical system;

- to simplify the determination of the end of charging of the battery system, the criteria of which are the achievement of a certain threshold voltage on the system and a minimum of current redistribution between groups;

- reduce the likelihood of undercharging, recharging, and exceeding the temperature of the batteries due to the redistribution of charging currents and voltages in the system.

The method improves the efficiency of using the charging network by increasing the load factor of the charger in terms of power and the percentage of simultaneity in charging the batteries served by this charger.

Figure 1 shows, for example, the characteristic of the normal mode 1 of the Nickel-cadmium battery, charged by a current corresponding to its nominal capacity, for 6 hours [Batteries and batteries alkaline nickel-cadmium and nickel-iron. Technical description and operating instructions 0.358.011TO]. For this method of charging batteries, it is assumed that charging a battery having a reduced capacity, proportionally reduced (relative to rated) charging current, is the normal mode for this battery. Families of characteristics 2, 3 reflect the processes of redistribution of current and voltage in a rechargeable battery system.

Figure 2 shows in general terms a diagram of the charging of batteries by the method of their arrangement in a system according to the principle of separation of capacities. The process of assembling accumulators or batteries, which are connected to switched charging cells, into the NW system (8) is carried out automatically by a computer (1) or manually by an operator (2), using the KKU component switching device (4). The process of charging the battery system from the charger charger (3) is controlled automatically or by the operator. The charger includes a device UIRZK (6) with elements of measurement, regulation and protection for groups of batteries of the charging system included in the corresponding channels K (7). The charging current source IZT (5) generates current in the system.

The proposed method of charging the battery system is as follows.

1. Layout and charging

The processes of assembling (CCM) of a system (CLC) of batteries in groups (C) of the total number of rechargeable batteries and their charging (memory) can be carried out automatically using computer technology using a specially developed program (computer) that takes into account the loss of capacity and the degree of charge of the battery. To do this, batteries or batteries must be connected to personalized cells KKU.

The layout and charging can be done manually, by the operator, according to the data of the battery status register, the results of the CTC and the readings of the UIRZK devices.

2. Determination of current and charging time

The value of the charging current for groups can be determined by empirical formulas, for example, by the formula

i _zg = C _ISM / T _ind ,

where i _zg is the determined charging current in the group;

With _ISM - the sum of the measured values of the capacity of all the batteries in the group;

T _ind - the sum of the individual values of the battery charging time, which is calculated for each battery according to the normal characteristics (figure 1) from the point of initial voltage to the point of the end of charging.

The determination of the end moment of charging by the threshold voltage is facilitated by the maximum convergence of the families of characteristics of the modes close to normal (see Fig. 1).

3. Source and charger

A silicon rectifier unit, for example, VAKZ-1-40, supporting a given current in a continuous mode, can serve as a source in the charger.

To charge the battery system, a pulse charger can be used, for example, an automatic charger of the RLEC series by Michael Riedel, when the efficiency of the charging process can be improved by scanning the status of the system of batteries differentiated by capacity.

The application of the proposed method increases the efficiency of the charging process by more than 10 ÷ 15%. The operational efficiency of existing charging networks in some cases can increase by 30% or more.

Claims (1)

A method of charging batteries with their arrangement in a system according to the principle of separation of capacities, in which the batteries or batteries are divided into groups, which include batteries of the same type and similar in value to their measured capacity, with an equal number of batteries connected in series in different groups, and charge the groups batteries simultaneously and in parallel, as a system, from a single source or charger, forming a system charging current, defined as the sum of currents depending on the measured capacity batteries in groups.

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