Abstract:
A device for the accumulation of electrical energy contains a gas-electric battery having a hollow housing, partially filled with an electrolyte solution, and electrodes, positioned inside the hollow housing and made of a conductive adsorbent of the electrolysis gases. The electrodes are divided by a gas-permeable separator. Current-collectors linked to the electrodes are connected to a charge-discharge converter designed to allow for a periodic change in the polarity of the charge current during the charging process. The device makes it possible to provide a long operating life with minimal environmental pollution.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is a continuation of International Application No. PCT/RU2012/000441, filed Jun. 6, 2012, which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention generally relates to the field of electrotechnology and, in particular, to secondary chemical of electricity that can be used in industrial and household applications. 
       BACKGROUND 
       [0003]    Several electrochemical energy batteries can be used, either independently or together with different primary electricity generators (e.g., photovoltaic cells, wind generators and other such devices), to even out peaks of energy demand on power grids. In the latter the battery is charged from the grid and releases power into a load during peaks of demand. 
         [0004]    One known battery type is the so-called gas-electric battery (see, e.g., RU 2056676 (C1), Arshinov et al., Mar. 20, 1996), which has been widely described in the literature. An earlier publication (SU 48659, Akimushkin, Jul. 12, 1935) describes a gas battery, the effect of which is based on the exploitation of a gaseous galvanic chain that develops in a hermetically sealed housing filled with a solid adsorbent for the gas. When a constant charge current passes between the electrodes, electrolysis of the electrolyte (e.g., a sodium chloride solution) causes the release of hydrogen and chlorine, which are captured by the adsorbent in the areas near the electrode. Hydrogen is adsorbed in the area of the negative electrode and chlorine in the area of the positive electrode, in accordance with the reaction: 2NaCl+2H 2 O→H 2 +Cl 2 +2NaOH. 
         [0005]    When the electrodes are connected to a load, a reverse chemical reaction takes place: H 2 +Cl 2 +2NaOH→2NaCl+2H 2 O. The shortfalls of this battery are the clogging of the electrodes, resulting in a reduction of the electric capacity, and also electrolyte deterioration due to an accumulation of NaOH. As a result, the lifetime of the battery is about 100 cycles. The limited lifetime makes it impossible to use this battery on an industrial scale. 
         [0006]    Known devices for battery charging (see, for instance, SU 775816, Belonoshko et al., Oct. 30, 1980; RU 2038672 C1, Gulyayev et al, Jun. 27, 1995) use charge-discharge converters for electric energy accumulation systems. However, these devices are not designed for operation in a gas-electric battery, which is characterized by the slowness of the electrochemical reactions that occur, and do not solve the task of extending its lifetime. 
         [0007]    Therefore, there is a need for a device for accumulating electrical energy based on a gas battery where the device has a long operating life and minimizes pollution to the environment. 
       SUMMARY 
       [0008]    Disclosed herein are example aspects of a device for the accumulation of electrical energy comprising a gas-electric battery including a hollow housing partly filled with an electrolyte solution and electrodes positioned in the hollow space of the housing and made of a conductive adsorbent of electrolysis gases. The electrodes may be divided by a gas-permeable separator. Current-collectors connected to the electrodes may be connected to a charge-discharge converter designed to allow for a periodic change in the polarity of the charge current during the charging process. 
         [0009]    The conductive adsorbent may be activated carbon, activated carbon black, activated graphite, colloidal carbon, pyrocarbon or mixtures thereof, whereas the electrolyte may be an aqueous sodium chloride solution. 
         [0010]    An upper panel of the battery housing may include a protective valve and a valve for creating overpressure in the housing, and an adsorbent layer may be placed under the upper panel of the housing, separated from the electrodes by a separator. Nozzles for supplying and releasing the electrolyte may also be arranged in the housing. 
         [0011]    In certain example aspects, a charge-discharge converter may comprise three filters, two of which may be arranged at an inlet and outlet of the converter while the third may be connected to the electrodes of the gas-electric battery. The charge-discharge converter may also comprise three pairs of symmetric two-way switches, a triple-wound transformer, a control unit activating a device for the formation of control voltages, and a control logic. Each of the filters may be connected by one of its outlets to a pair of the two-way switches connected in-series the ends of one of the windings, and by its other outlet to the center of the winding. The inlet of the control unit may be connected to sensors for measuring parameters of the gas-electric battery, while its control outlet is connected to the switches. The sensors for measuring the parameters of the gas-electric battery can activate sensors for voltage, current, temperature, pressure of the gases and the pH of the electrolyte solution. 
         [0012]    The above simplified summary of example aspects serves to provide a basic understanding of the present disclosure. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects of the present disclosure. Its sole purpose is to present one or more aspects in a simplified form as a prelude to the more detailed description of the disclosure that follows. To the accomplishment of the foregoing, the one or more aspects of the present disclosure include the features described and particularly pointed out in the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The accompanying drawings illustrate one or more example aspects of the invention and serve to explain their principles and implementations. 
           [0014]      FIG. 1  illustrates an example aspect of a gas-electric battery. 
           [0015]      FIG. 2  illustrates an example aspect of a charge-discharge converter in which two-way switches are used together with a gas-electric battery. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Example aspects are described herein in the context of a device for the accumulation of electrical energy. Those of ordinary skill in the art will realize that the following description is illustrative only and is not intended to be in any way limiting. Other aspects will readily suggest themselves to those skilled in the art having the benefit of this disclosure. Reference will now be made in detail to implementations of the example aspects as illustrated in the accompanying drawings. The same reference indicators will be used to the extent possible throughout the drawings and the following description to refer to the same or like items. 
         [0017]    As shown in  FIG. 1 , a gas-electric battery for use in a device for the accumulation of electrical energy includes a battery  1  having a hollow housing with an upper panel  2  and a floor panel  3 . Electrodes  4 ,  5  arranged in the hollow of the housing are made of a conductive adsorbent for adsorbing gases that form during the electrolysis process. The conductive adsorbent may be activated carbon, activated carbon black, activated graphite, colloidal carbon, pyrocarbon or mixtures thereof. In certain aspects, current-collectors  6  and  7  form an electric energy outlet. The electrodes  4 ,  5  are separated from each other and also from the adsorbent by separators  8  and  9 . To prevent gas leakages, an adsorbent  10  is arranged above the electrodes. The housing of the battery  1  is at least partially filled with electrolyte  11 , and to supply and release the electrolyte  11 , nozzles  12 ,  13  are arranged in the housing. To check the function of the battery  1 , sensors  14  for measuring parameters, such as voltage, current, temperature, the pressure of the gases and the pH of the electrolyte solution, may be arranged within the housing. A protective valve  15  and a valve  16  for creating overpressure in the housing, connected to a pump  17 , are arranged on an upper panel  2  of the housing  1 . 
         [0018]    As shown in  FIG. 2 , the gas battery  1  can function within a charge-discharge converter. Notably, in certain example aspects, it is possible to use separate charge and discharge converters that switch over when the processes of charging and discharging are finished. 
         [0019]    The charge-discharge converter may also function as a voltage stabilizer and includes three filters  20 ,  21 ,  22 , three pairs of symmetric two-way switches  23 - 24 ,  25 - 26 ,  27 - 28 , a triple-wound transformer  29  and a control unit  30 . Two filters  20  and  21  are arranged at the inlet  31  and at the outlet  32  of the converter, which is connected to a load or grid, while a third filter  22  is connected to current-collectors  6  and  7  of electrodes  4 ,  5  of the gas-electric battery  1 . The control unit  30  includes control logic as well as a control voltage formation device for the switches  23 - 24 ,  25 - 26 ,  27 - 28 . Each of filters  20 ,  21  and  22  are connected by a corresponding outlet to a pair of two-way switches  23 - 24 ,  25 - 26  or  27 - 28  that are connected in series to the ends of windings of transformer  29 , and with their other outlet at the center of the respective winding. The inlet of control unit  30  is connected to sensors  14  for receiving parameters of the gas-electric battery  1 , while the outlet of control unit  30  is connected to switches  23 - 24 ,  25 - 26 ,  27 - 28 . 
         [0020]    The triple-wound transformer  29  provides a decoupling between the inlet  31  and the outlet  32  of the converter, which makes it possible to provide a charge and discharge converter in the same device, and also to stabilize the outlet voltage to improve the power factor of consumption from a source, and to release excess power back into the power grid. The operating frequency of the converter is dependent on the elements to be employed and can be between tens and hundreds of kilohertz. Filters  20 ,  21 ,  22  prevent transfer of frequency from the converter into the power grid, load or battery, eliminate parasitic harmonics, provide necessary impedance, and provide a reduction in the level of electromagnetic interferences. 
         [0021]    The device works in the following manner. In a charging mode, inlet voltage  31  passes through filter  20  to switches  23 ,  24  to function as a push-pull converter. By means of the transformer  29 , the converted voltage passes to a synchronous rectifier provided on the switches  27 ,  28  then through the filter  22  to the battery  1 , thereby charging it. Simultaneously, the converted voltage from the transformer  29  can be rectified by switches  25 ,  25  to function as a pulsed voltage stabilizer, and passes through filter  21  to the outlet  32  (exit voltage stabilization mode). 
         [0022]    In a discharging mode, the voltage from battery  1  passes through filter  22  to switches  27 ,  28 , this voltage is converted into a high-frequency voltage. The converted voltage passes from the transformer  29  to a synchronous rectifier provided on the switches  25 ,  26  for rectification, then passes through the filter  21  to outlet  32 . Switches  23 ,  24  can be in either a switched-off state, in a converter mode, depending on the control pulses of the control unit  30  to increase the power at the outlet (modes of equalizing the demand peaks or correcting the power), or in a synchronous rectifier mode (mode of returning a part of the power into the power grid). 
         [0023]    Switches  23 - 28  are controlled according to signals from the voltage formation device of the control unit  30 , which includes sensors  14  for measuring the parameters of voltage, current, temperature, pressure of the gases and the pH of the electrolyte solution, and also the control logic. 
         [0024]    In the charging mode, the voltage from a source of energy (for instance, from a photovoltaic cell), which passes to inlet  31  of the converter, is converted into a charge current passing through current-collectors  6  and  7  to electrodes  4  and  5 . Under the influence of electric current, electrolysis process takes place in the electrolyte  11 . The electrolyte solution  11  dissolves, forming reaction products and releasing gaseous components. When a sodium chloride solution is used as the electrolyte  11 , the products, hydrogen and chlorine, are adsorbed by the unwound surface of the electrodes  4  and  5 , while in the electrolyte  11 , sodium hydroxide (NaOH) is accumulated according to the following chemical reaction: 2NaCl+2H 2 O←→H 2 +Cl 2 +2NaOH. 
         [0025]    The battery capacity is defined by the surface area of the conductive adsorbent, for instance, activated carbon, which forms the body of the electrodes. When the battery is discharged, the adsorbent gases are released from the electrodes  4  and  5  and again join the reaction with sodium hydroxide to form the sodium chloride solution. However, water insoluble salts (for instance, calcium salts and others) contained in the material of the electrodes  4 ,  5  and the electrolyte  11  can precipitate onto the electrodes  4 ,  5  and reduce sorption capacity (i.e., the usable area of the electrodes) correspondingly reducing electric capacity. Furthermore the hydrogen may be retained by the electrode material which is essentially worse than chlorine, and after discharging the battery, part of the chlorine may remain on the electrode. 
         [0026]    When the polarity of the converter in the charging mode changes, residues of the gases flow from the electrodes to the outside where they interact with a different gas which starts forming in the electrolysis process. The chemical reaction between the gases results in the formation of hydrochloric acid, which dissolves the water insoluble salts, thus cleansing the electrodes  4 ,  5 . A portion of the gases formed in the electrolysis process are released from the surface of the electrodes and accumulate under the top panel  2  of the housing  1 . To prevent their leaking and, as a consequence, a deterioration of the properties of the electrolyte  11 , an additional layer of adsorbent  10 , for example activated carbon, is arranged above the electrodes  4 ,  5 . 
         [0027]    While it alternately (at the change of polarity) adsorbs various gases, a chemical reaction occurs, wherein hydrochloric acid is formed, which is neutralized by alkali that forms during electrolysis. The resulting sodium chloride solution is used again in the electrolysis process. The degree of adsorption depends on the pressure. It is possible to increase the degree of adsorption and thus increase the battery capacity by raising the pressure within the housing, to which end it is possible to use valve  16  for creating an overpressure from pump  17  within the housing. 
         [0028]    To check the parameters of the battery  1 , sensors  14  can be arranged within it to measure basic operation parameters of battery function, such as the temperature, the pressure, the pH, the number of activations of the protective valve, the electrolyte level. In the event of an overcharging of the battery  1 , for instance in the event of a failure of the charge converter or a failure of a pressure sensor, the gas pressure within the housing can rise above a permissible level. To prevent a destruction of the housing, the device can be provided with a protective valve  15 . Information from the sensors can be transmitted to a service team to assess the necessity of maintenance or repair, which has a positive impact on the safety and lifetime of the device. 
         [0029]    Experiments have shown that the relative accumulation capacity, defined as the relationship of the actual value to the value in the first cycle, depending on the number of “charging-discharging” cycles, remains within permissible boundaries for a number reaching several thousand cycles. Simultaneously, in a battery of identical construction it was reduced by a multiplicity of ten when charging was done without changing the polarity of the charge current. 
         [0030]    The device can be applied in alternative electrical energies together with photovoltaic cells, wind generators and other similar electricity generators. The device can also be used to even out peaks in demand of electric power by users of electricity grids which enhances the effectiveness of usage of existing electric power stations and electric power transmission lines, reduces the deficit in electric power, and makes it possible to avoid cyclic power cutoffs. The device can be carried out using traditional technologies, materials and elements. The device can withstand total discharges as well as quick charging with increased current without suffering damage, and is constructed in a simple way from readily available materials. 
         [0031]    In the interest of clarity, not all of the routine features of the aspects are disclosed herein. It will be appreciated that in the development of any actual implementation of the invention, numerous implementation-specific decisions must be made in order to achieve the developer&#39;s specific goals, and that these specific goals will vary for different implementations and different developers. It will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure, 
         [0032]    Furthermore, it is to be understood that the phraseology or terminology used herein is for the purpose of description and not of restriction, such that the terminology or phraseology of the present specification is to be interpreted by the skilled in the art in light of the teachings and guidance presented herein, in combination with the knowledge of the skilled in the relevant art(s). Moreover, it is not intended for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. 
         [0033]    Those of ordinary skill in the art will realize that the above description is illustrative only and is not intended to be in any way limiting. Other aspects will readily suggest themselves to those skilled in the art having the benefit of this disclosure. Moreover, it would be apparent to those skilled in the art having the benefit of this disclosure that many more aspects and modifications than mentioned above are possible without departing from the inventive concepts disclosed herein.