WO2002025793A1

WO2002025793A1 - Method of commutation and installation of high capacity accumulators

Info

Publication number: WO2002025793A1
Application number: PCT/CA2000/001050
Authority: WO
Inventors: Dmitry N. Borisenko; Nikolay N. Borisenko
Original assignee: SELECT MOLECULAR TECHNOLOGIES Corp
Current assignee: SELECT MOLECULAR TECHNOLOGIES Corp
Priority date: 2000-09-19
Filing date: 2000-09-19
Publication date: 2002-03-28
Anticipated expiration: 2003-03-19
Also published as: AU2000272634A1

Abstract

A method for communicating a high capacity accumulator is carried out based on the distinctive nature of a high capacity accumulator from traditional electro-chemical charging-discharging sources of energy (HIT). In an embodiment, a high capacity accumulator has multiple modules. Each module has an electrolyte and one or more cells. Each cell including a pair of electrodes. The accumulator is communicated by connecting all modules in the accumulator in parallel to a charging device, and charging the accumulator by the charging device.

Description

Method of Communication and Installation of High Capacity Accumulators

This invention relates to a method of communication and installation of high capacity accumulators.

BACKGROUND OF THE INVENTION

In traditional electro-chemical charging-discharging sources of energy (HIT) having electrodes and an electrolyte, there are chemical reactions between the electrodes and the electrolyte.

The charging of an HIT is usually done at a certain stable value of a charging current during a certain amount of time. This provides a required electrochemical transformation of a certain amount of the working substance. The value of the charging current during the whole period of time of charging is limited. If the value of the charging current or the time period for the charging is increased, chemical reactions in the HIT become out of control.

When a high capacity accumulator is used, work conditions are different from such traditional HITs. Accordingly, it is desirable to provide a different method for communicate the high capacity accumulator to charge and discharge.

SUMMARY OF THE INVENTION

The present invention provides a method for communicating a high capacity accumulator based on the distinctive nature of a high capacity accumulator from traditional electro-chemical charging-discharging sources of energy (HIT).

In accordance with an aspect of the present invention, there is provided a method for communicating with a high capacity accumulator having multiple modules. Each module has an electrolyte and one or more cells. Each cell including a pair of electrodes. The method comprises connecting all modules in the accumulator in parallel to a charging device, and charging the accumulator by the charging device.

In accordance with another aspect of the present invention, there is provided a method for charging a high capacity accumulator module having one or more cells. Each cell includes a pair of electrodes. The method comprises determining a non-over voltage which is nominal for the cells, taking into consideration of its realization in the module of connection to a charging device in series, parallel and any combination thereof; setting a charging voltage based on the non-over voltage; and charging the accumulator by the charging device using the charging voltage.

In accordance with another aspect of the present invention, there is provided a method for communicating with a high capacity accumulator having multiple modules. Each module has a body enclosing an electrolyte and one or more cells. Each cell includes a pair of electrodes. The method comprises connecting the modules such that the connection of the modules are switchable between series connection and parallel connection to an energy user; discharging the accumulator to the energy user; and switching the connection between the series connection and parallel connection during the discharge.

In accordance with another aspect of the present invention, there is provided a method for discharging a high capacity accumulator module having one or more cells. Each cell having one or more pairs of electrodes. The method comprises connecting the cells such that the connection of the cells are switchable between series connection and parallel connection to an energy user; discharging the accumulator module to the energy user; and switching the connection between the series connection and parallel connection during the discharge.

Other aspects and features of the present invention will be readily apparent to those skilled in the art from a review of the following detailed description of preferred embodiments in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further understood from the following description with reference to the drawings in which:

Figure 1 is a graph showing a typical charging characteristic of an EMONA;

Figure 2 is a graph showing a typical discharging characteristic of the EMONA;

Figure 3 is a graph showing a typical charging characteristic of an HIT;

Figure 4 is a graph showing a typical discharging characteristic of the HIT; and

Figure 5 is a graph showing discharge characteristics of a battery consisting of two EMONA modules when using a switch between modules of parallel to subsequent connection.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is suitably used for a high capacity accumulator, such as an EMONA. EMONA is a device consisting of at least one, more often, of several, cells separated among themselves and from the current collectors by chemically inert conducting separators invisible for particles of the electrolyte; each of these cells includes in itself a couple of electrodes consisting of one or multi-layer chemically inert carbonised activated conducting woven fabric, which has a developed surface, active centres and orderly structure; the electrode pairs are separated among themselves by a chemically inert non-conducting transparent for the particles of electrolyte membrane. The whole device is enclosed in an airtight case.

The electrolyte that is used in this case is a liquid substance (pure liquid, liquid mixture, solution, gel and the like). The electrodes and the chemically inert non-conducting transparent for the particles of electrolyte membrane are saturated with this substance.

The electrolyte is usually in the adsorbed state in the material of electrodes and the membrane, where the free volume of the electrolyte is absent.

The electrolyte is in direct contact with the chemically inert conducting surface of both electrodes.

Each cell of EMONA is originally symmetrical in relation to the chemically inert non-conducting transparent for the particles of electrolyte membrane.

One of the substantive distinctions of the known HITs is the choice of such materials and conditions for the work of EMONA which allow absence of any chemical reaction between the electrolyte and the electrodes. The energy collection is possible primarily due to the arrangement of the electrolyte particles.

Therefore, the mass transformation on the electrodes is absent and it ^• becomes impossible to use formulas corresponding to HITs of the kind dm=k^*dQ where m is the mass of the substance that reacted; k is the electrochemical index and Q is the charge that took place, etc. It is impossible to operate within the parameters of ampere-hours, etc.

As a result of the above-mentioned distinctive features, the characteristics of EMONA (Figures 1 and 2) are substantially different from the characteristics of HITs (Figures 3 and 4); also, the difference exists in the demands and limitations of the conditions for charging and discharging. Therefore, the engineering approach to the commutation and installation is different for the purpose of providing the maximum activity and longevity of service for such devices.

For example, when charging EMONA (Figure 1), certain value of the charging voltage U_ch provides certain limitations. Its increase provides a negative influence on the longevity of the device service. During the initial period of charging, the amount of the charging current can be unlimited and is defined only by the correlation between the user's resistance and the source under the running voltage. Once the value of the voltage U_reg is reached, the amount of the charging current must be forcefully decreased based on the need not to increase U_ch. The time for charging is not limited. Provided that there is an unlimited amount of time for charging, the charging current will decrease to zero and voltage on EMONA will be equal to the charging voltage.

During the discharge of EMONA (Figure 2), the voltage is decreased from a certain level of voltage U_nom down to zero (subject to an unlimited amount of time for charging). The resulting minimum voltage is not limited. The discharging characteristic on a big space can be described exponentially but following correlation

U=Uo*EXP R*C

(for charging, continuous resistance), where U and Uo are the running and the original voltage respectively, B; t is the time in seconds; R is the resistance of the chain, Om; C is the capacity, F. The discharging current can be of any value even that of the short circuit. EMONA also allows connection to the source under the conditions of reversed polarity and into the chain of the alternative current.

This allows a hundred percent discharge of the devise without any influence on the characteristics and the longevity of its service.

The charging of HITs (Figure 3) is usually done at a certain stable value of the charging current l_ch during a certain said amount of time from zero to T_end. This provides the required electrochemical transformation of a certain amount of the working substance. The value of the charging current during the whole period of time of charging is limited, increasing the value of the charging current or the time period for the charging results in HITs getting out of order.

During the charging the voltage on the device changes in very minute amounts.

During the discharge of the HITs, as well as during their charge, the amount of the working substance which reacted that is proportional to the spent charge serves as a limiting factor. The discharge is limited by a certain amount of time from zero to T_end, during which the voltage decreases to U_end. The charging characteristics over a large period of time can be described in a linear dependance. Fluctuations in the voltage are limited during further discharge and with the corresponding decrease in the voltage the device gets out of order because of the side effect chemical reactions. A very minimal change in the voltage on the device is allowed.

Discharges by currents over a certain value are also not allowed because of possible side effect reactions in the working substance. Therefore, no more than 25-50% of the saved energy can be given into the outside network without negatively influencing the longevity of the device service. Characteristics of Charging EMONA

A EMONA accumulator or battery may comprise multiple EMONA modules. Each module has the structure as described above. When charging two or more modules of EMONA from the same charging device, all modules are connected to it in parallel. This guarantees that the charging voltage does not get over the nominal value for all the modules.

If they are connected in series, subject to the same current, going through all the modules, even with minute differences in the volumes and resistance of certain modules, the voltage in them will be different. This can result in the voltage on one of the modules exceeding the level allowed, thus leading to the increase in the resistance caused by over voltage, and subsequent increase in the voltage on the module. All of this will result in the module getting out of order and the battery being useless for any further exploitation.

Such reaction is observed only when the modules are connected in series to the source. If a single module is taken, which contains as a rule two or more cells connected in series, such reaction is not observed. This can be explained by the fact that all cells of the modules connected in series are contained in a single air-tight case and the fact that a certain clearance exists between the cells and the walls of the device, and the facing side of each cell communicates with the atmosphere of the general clearance of all the cells. Within such general clearance, dynamic leverage is established between the electrolyte, adsorbed by the electrodes, the membrane, on the fumes, the aerogel and the electrolyte condensate. When such a system is discharged, the existing differences between separate cells are compensated due to the additional evaporation and adsorption of the electrolyte. Quick compensating leveraging of the parameters of the cells is possible due to a limited amount of the electrolyte (the free amount is absent) and a large surface available for the evaporation and adsorption. In case of the HITs, consisting of two or more elements, their getting out of order is associated with the difference in the parameters of separate elements. In such cases the realization of such compensating method of leveraging the parameters of separate elements is complicated due to the fact that there exists a large volume of the running electrolyte and a small surface on which evaporation and condensation can take place. The amount of time necessary for such compensation would be high and the system would not be able to catch up with the leveraging each time during the average statistical charge cycle. The voltage on any such element usually does not go about 3V. The process of charging a battery of such isolated elements connected parallelly will not provide consumer qualities of the device, and furthermore will demand additional control over the charging current.

Qualities of Discharging the EMONA

Although it is possible to use 100% of the saved energy of EMONA reflected in the formula

where E is energy, J; C is volume, F; U is voltage, V. Certain difficulties exist which are caused by the decreasing characteristics of voltage and the corresponding necessity to use low potential energy.

It has been practically defined that, without causing decrease in the customer qualities of most electric devices, it is possible to allow the decrease in the voltage on this source no more than by 50% which equals energy output of 60-75%, saved by EMONA, without the facility of additional regulating. This value is already substantially higher than that exhibited by other known HITs. Since the energy output to the consumer is E=l*U*t, it is possible to increase the energy output only by increasing U on the source during the process of discharge (the current is defined only by the internal resistance of the user and is its characteristic).

The use of electronic schemes for the regulation of voltage on EMONA during the process of discharge does not lead to the increase in its efficience, since KPD of such transformation does not exceed 80-93%, that is no less than 7-20% of the energy output by EMONA is consumed by the process of transformation. At the same time the presence of such additional regulating device substantially complicate the device and makes it more expensive. The use of such scheme is reasonable only when the user is itself very sensitive to the change in the voltage.

The present invention allows an increase of the energy output in the following way:

EMONA is a battery consisting of at least one pair of separate modules which have identical nominal voltage, primarily identical capacities, can be united in a single body or placed in separate bodies.

At the beginning of the discharging cycle the battery modules are connected in parallel.

When reaching a certain value of voltage and the output current which is defined on the basis of the serviceability and user qualities of the electric instrument.

For example, when decreasing the output power by 50%), the EMONA modules are switched from the parallel to the subsequent connection, which transfer increases voltage by two fold and once again allows the output to the user of the necessary power. Such transfer can be performed once or several times depending on the available number of modules - both within the pair, and between pairs of modules.

Usually, one switch is performed. This is caused by the fact that each such switch leads to the quadruple diminishing of the battery capacity and the quadruple increase in its resistance, as well as the complication of the commutation scheme of the EMONA battery.

The above mentioned switch can be performed both manually and automatically, for example, by means of relay.

The efficiency of such method is especially obvious in situations when the characteristic of EMONA is different from the exponential dependence in such a way that the capacity at lower voltages is larger than the capacity in the initial discharge.

The EMONA battery specifically designed for the use as a power source in hand flashlight consists of two modules with nominal voltage of 3V; capacity, which is measured between 3.0 and 1.1watt at 684F, and which is measured from 1.0 to 0.368V - 947F. A bulb fed from such a battery provides a satisfying stream of light at the voltage up to 1.8V. The discharge characteristic is described on Figure 5.

After charging the EMONA battery for 15 minutes, the longevity of good luminous emittance is 70 minutes, which period is necessary for the output of about 64% of the stored energy. When switched to the subsequent connection, 110 minutes, and the output of 91% of the saved energy. Such efficiency of the energy output is impossible either with any other known type of charge-discharge power source, or any other method of commutation.

The commutation and installation of the EMONA according to the present invention are described bellow. First, the installation or charging of the EMONA is described.

When charging the EMONA battery which comprises two or more modules, all separate modules of the battery are connected to the charging device in parallel.

When the EMONA battery has modules which have identical nominal voltage, the voltage of charging does not exceed the nominal voltage for any separate module.

When the battery has separate modules which have varying nominal voltages, the voltage of charging the battery is established at no higher than the nominal voltage for the module that has the minimal nominal voltage.

Each EMONA module comprises one or more cells. The nominal voltage of charging is prescribed based on the guaranteed non-over voltage, nominal for any separate cell, taking into consideration its realization in the module in series parallel, or combined plugging during the charge.

The EMONA module is enclosed in a single airtight body containing all cells, where a clearance exists between the walls of the body and the facing side of all cells, where a single equilibrium atmosphere for all cells is created. The EMONA module may have separate cells which include mostly of identical substances and materials (chemically inert electrodes; electrolyte; separators conducting chemically inert non-transparent for the electrolyte particles, membranes non-conducting chemical inert non-transparent for the electrolyte particles). The separate cells may have identical nominal voltages, primarily identical capacities and/or primarily identical conductance.

The discharging is carried out as follows for an EMONA battery which comprises at least two modules. The modules have separate bodies or are connected in pairs or more in any separate body. Their commutation is conducted in a way that for at least two modules, or at least two groups of modules, switching is possible between their parallel and series connection to the user.

The switching is performed on the basis of energy output parameters, set by the energy user. The switching may be performed manually or automatically.

The commutation during the discharge allows multiple hierarchical switching between different modules in their groups, or within the groups.

When discharging the EMONA module, comprising two or more groups of cells connected in pairs within a single body, their commutation is performed in such a way that, at least for two groups of the cells, switching can be performed between their parallel and subsequent connection to the user.

The switching may be performed on the basis of the energy output parameters set by the energy user. The switching may be performed manually or automatically.

The communication during the discharge allows multiple hierarchical switching performed between different groups of cells.

The present invention is described using the EMONA. However, the above described method of communication and installation, i.e., charging and discharging can be used for other electric energy storage which have similar charge/discharge characteristics to the EMONA.

While particular embodiments of the present invention have been shown and described, changes and modifications may be made to such embodiments without departing from the true scope of the invention.

Claims

What is claimed is:

1. A method for communicating with a high capacity accumulator having multiple modules, each module having an electrolyte and one or more cells, each cell including a pair of electrodes, the method comprising steps of: connecting all modules in the accumulator in parallel to a charging device; and charging the accumulator by the charging device.

2. The method as claimed in claim 1 , wherein the charging step comprises steps of: determining if the modules have an identical nominal voltage; and setting a charging voltage such that the charging voltage does not exceed the nominal voltage.

3. The method as claimed in claim 1 , wherein the charging step comprises steps of: determining if the modules have different nominal voltages; determining a minimal nominal voltage among the different nominal voltages; and setting a charging voltage such that the charging voltage does not exceed the minimal nominal voltage.

4. The method as claimed in claim 1 , wherein each cell has a pair of electrodes having a layer of chemically inert conducting layer, and the pair of the electrodes are separated by a chemically inert non-conductive membrane which is transparent for the electrolyte.

5. A method for charging a high capacity accumulator module having one or more cells, each cell including a pair of electrodes, the method comprising steps of: determining a non-over voltage which is nominal for the cells, taking into consideration of its realization in the module of connection to a charging device in series, parallel and any combination thereof; setting a charging voltage based on the non-over voltage; and charging the accumulator by the charging device using the charging voltage.

6. The method as claimed in claim 5, wherein the module is enclosed in a single airtight body for accommodating the cells, the cells are accommodated in the airtight body such that a clearance exists between the walls of the body and the facing side of the cells and the body creates a single equilibrium atmosphere for the cells.

7. The method as claimed in claim 5, wherein the module has separate cells which consist substantially identical substances.

8. The method as claimed in claim 7, wherein the substances include chemically inert electrodes, electrolyte, conducting chemically inert separators which are non-transparent for the electrolyte particles, non-conducting chemical inert membranes which are non-transparent for the electrolyte particles.

9. The method as claimed in claim 5, wherein the module has separate cells which have identical nominal voltages.

10. The method as claimed in claim 5, wherein the module has separate cells which have primarily identical capacities.

11. The method as claimed in claim 5, wherein the module has separate cells which have primarily identical conductance.

12. A method for communicating with a high capacity accumulator having multiple modules, each module having a body enclosing an electrolyte and one or more cells, each cell including a pair of electrodes, the method comprising steps of: connecting the modules such that the connection of the modules are switchable between series connection and parallel connection to an energy user; discharging the accumulator to the energy user; and switching the connection between the series connection and parallel connection during the discharge.

13. The method as claimed in claim 12, wherein the switching step is carried out for groups of modules.

14. The method as claimed in claim 12, wherein the switching step is performed on the basis of energy output parameters set by the energy user.

15. The method as claimed in claim 12, wherein the switching step is performed manually.

16. The method as claimed in claim 12, wherein the switching step is performed automatically.

17. The method as claimed in claim 13, wherein the connecting step allows multiple hierarchical switches between different modules in their groups or within the groups.

18. The method as claimed in claim 12, wherein each cell has a pair of electrodes having a layer of chemically inert conducting layer, and the pair of the electrodes are separated by a chemically inert non-conductive membrane which is transparent for the electrolyte.

19. A method for discharging a high capacity accumulator module having one or more cells, each cell having one or more pairs of electrodes, the method comprising steps of: connecting the cells such that the connection of the cells are switchable between series connection and parallel connection to an energy user; discharging the accumulator module to the energy user; and switching the connection between the series connection and parallel connection during the discharge.

20. The method as claimed in claim 19, wherein the switching step is carried out for groups of modules.

21. The method as claimed in claim 19, wherein the switching step is performed on the basis of energy output parameters set by the energy user.

22. The method as claimed in claim 19, wherein the switching step is performed manually.

23. The method as claimed in claim 19, wherein the switching step is performed automatically.

24. The method as claimed in claim 20, wherein the connecting step allows multiple hierarchical switches between different modules in their groups or within the groups.