WO2013041630A1

WO2013041630A1 - Electrolyzer unit and energy converter

Info

Publication number: WO2013041630A1
Application number: PCT/EP2012/068555
Authority: WO
Inventors: Richard Schalber
Original assignee: Inmares AG
Priority date: 2011-09-21
Filing date: 2012-09-20
Publication date: 2013-03-28
Also published as: DE102011054317A1

Abstract

The invention relates to an electrolyser unit and an energy converter comprising said type of electrolyseur unit. Said unit comprises and electrolyseur which forms a structural unit with an accumulator.

Description

Electrolyzer unit and energy converter

The invention relates to an electrolyzer unit according to the preamble of

Claim 1 and an executed with such an electrolyzer energy converter.

Especially after the departure of major industrialized countries from the

Nuclear energy technology and with the increasing use of electric vehicles and the expected significant shortage of oil in the future

Strive to use renewable energy as an energy source. Significant progress has recently been made in the fields of wind turbines, solar technology, the use of wave energy, etc. A disadvantage of electric

Propulsion systems for vehicles are the batteries / accumulators with considerable capacities, which determine the vehicle price and the vehicle weight very substantially.

Efforts have been made for some years now to use so-called fuel cells for energy conversion and then to power an electric motor. Other solutions envisage using hydrogen as fuel in an internal combustion engine. However, these efforts have been somewhat forgotten with the development of the above-mentioned electric vehicles with classic accumulator and purely electric drive technology.

A problem with the use of renewable energy for power supply is that the natural forces used in each case such as sun, wind, water are not constantly available in time, so it may happen that on the one hand too much energy is available or too low energy at peak load times available stands.

Therefore, great efforts are being made to create energy converters that can store available energy and then retrieve it when needed. Such energy converters can be used stationary or mobile. DE 10 2009 048 455 A1 describes a method and a device for storing electrical energy, in which an electrolyzer unit is used to split water into oxygen and hydrogen. Of the

Hydrogen is then directed to a storage tank and, if necessary, one

Fuel cell supplied to generate electrical energy.

A so-called "energy cell" in which the electrolysis unit is operated by means of a photovoltaic system is described at www.solarserver.de As explained, the electrolysis unit splits water into oxygen and hydrogen, wherein the hydrogen is stored in a buffer and the When there is no solar energy available, the hydrogen is mixed with oxygen from the environment or with the oxygen previously obtained with the electrolyzer in a fuel cell

merged, wherein hydrogen and oxygen are electrolytesichen converted to water and tapped the voltage applied to the electrodes electrical voltage. This DC voltage is then supplied by an inverter

usable alternating current converted. The resulting in the fuel cell water can be supplied to the electrolysis unit again.

Disadvantage of the above-described solutions is a relatively complex structure, since its own memory must be provided for buffering the hydrogen.

In contrast, the invention has the object, a

To provide electrolysis unit and an energy converter with such a Elektrolyseureinheit in which the device complexity is reduced.

This object is achieved by an electrolyzer unit with the features of claim 1 and an energy converter with the features of

independent claim 6 solved.

Advantageous developments of the invention are the subject of

Dependent claims. The electrolysis unit according to the invention for the decomposition of water in

Hydrogen and oxygen have a reservoir that forms a functional unit with the electrolyzer itself.

This solution turns away from conventional constructions in which the electrolyzer and storage were designed as separate units and had a corresponding space requirement. The integration of the electrolyzer in the memory or the memory in the electrolyzer a very compact unit is formed in which the wiring for the transfer of hydrogen and oxygen into the memory can be kept much simpler than in the conventional solutions. It is known that in such electrolyzer units considerable pressures may occur, so that the memory is preferably designed as a pressure vessel in which the

Electrolyzer unit is fully or at least partially integrated. Of the

Pressure vessel is designed for a relatively high pressure, for example in the range of 400 to 700 bar. In one embodiment of the invention, the memory has two separate storage sections in which hydrogen or oxygen is stored. The respective storage section is connected via a gas flow path to the corresponding outlet of the electrolyzer. According to the invention, it is preferred if the electrolysis unit is designed as a galvanic electrolysis unit. Such Elektrolyseureinheiten are characterized by a high efficiency, which is over 80%.

To keep costs down, the electrodes are made from readily available materials such as stainless steel. In order to increase the tapped voltage, a plurality of electrodes are laminated into a package in parallel, wherein between the individual electrodes suitable plastic seals are made. The energy converter according to the invention is provided with an inventive

Electrolyzer unit executed and has an energy source through which the

Electrolyzer unit is operated. The energy converter further has a cell for generating electrical, thermal and / or mechanical energy from the hydrogen and oxygen generated in the electrolyzer unit.

This cell may be implemented as a fuel cell and may be used to charge an energy peak storage, for example a supercope or accumulator with electric drive.

In an alternative solution, the cell is designed as a burner in which the mixture of hydrogen and oxygen (oxyhydrogen) is burned.

Such a burner can be designed with a heat exchanger to heat a heat transfer medium.

By means of such a heat exchanger, the thermal energy released in the fuel cell can also be used to heat another medium. Since water is obtained as the reaction product in the fuel cell, this can be recycled back into the electrolysis unit.

The energy source can be operated, for example, with solar energy, with wind energy, with water energy or with kinetic energy of a utility device, for example an elevator, a car or the like in recuperation operation.

The energy converter according to the invention can be an accumulator of a

Electric motor or an electric motor itself provide energy. Preferred embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it: Figure 1 shows an embodiment of an energy converter, as it can be used for example in a mobile application and

Figure 2 is a circuit diagram of an energy converter for a stationary application.

Figure 1 shows a block diagram of a first embodiment of a

Energy converter 1, which can be used for example to charge a battery of a scooter or as an energy source for powering another stationary or mobile consumer. The energy converter 1 has an electrolysis unit 2 according to the invention, via which water into hydrogen and

Oxygen (H2O2) is decomposed. The electrolysis unit consists in principle of a structural unit with an electrolyzer 4 and a memory 6. This is in gas communication with a fuel cell 8, at a chemical reaction of the hydrogen produced by the electrolyzer 4 and oxygen, either from the memory 6 or can be taken from the environment one

DC voltage U can be tapped. As explained above, this can

DC voltage to be converted via an inverter into AC voltage. The resulting in the fuel cell 8 reaction enthalpy is over a

Heat exchanger 10 used to heat a heat transfer medium 12 or other medium. As will be explained in more detail below, arises in the fuel cell 8 water as a reaction product. This heated water can be cooled, for example, in the heat exchanger 10 to the

Heat transfer medium 12 to heat. The cooled water is then passed through a return line 13 back to the electrolyzer.

The electrolyzer 4 is an alkaline electrolyzer, wherein, for example, potassium hydroxide (KOH) is used as the electrolyte. In one embodiment, the electrodes are made of stainless steel in a very simple and inexpensive manner.

Of course, other suitable electrodes of higher quality materials may be used.

As shown schematically in FIG. 1, the electrodes 14 are arranged in a stape-shaped manner and are provided via suitable ring seals, for example made of Viton spaced. The electrolyte is located between each two adjacent

Electrodes. These are connected in parallel and are acted upon by a voltage source with a working voltage UA. The power supply can be done for example via photovoltaic elements 16. The electrodes 14 are connected in parallel with the power of the electrolyzer 4, i. the amount of gas that can be generated is determined by the number of electrodes and / or the electrical power of the power supply. In the described embodiment, sun is used as the energy source.

Alternatively, of course, other renewable energies,

For example, wind or hydro power can be used. It is also conceivable, in principle, for the energy released during the deceleration of kinetic energy

(Recuperation) to operate the electrolyzer 4. Such recuperation is conceivable, for example, when braking a vehicle or when lowering a load, for example an elevator. The electrode stack is clamped between two housing plates 18, 20. Of the

Electrolyzer has an inlet 22 to which the return line 13 is connected. Via this inlet 22, the water produced as reaction product in the fuel cell 8 thus flows back to the electrolyzer 4. This also has two

Gas outlets 24, 26, wherein the gas outlet 24 is connected to the area of the electrolyzer, in which hydrogen is produced. The other gas outlet 26 is in communication with the area in which the oxygen is obtained.

The gas outlet 24 is connected to a hydrogen storage 28 and the gas outlet 26 is connected to an oxygen storage 30, which are integrated into the storage 6 and are separated from each other by a storage wall 32, for example. As Figure 1 is removed, the electrolyzer 4 is inserted into a container wall 34 of the memory and encompassed by this at least in sections. In principle, the electrolyzer 4 could also form part of the container wall 34. These

Container wall 34 is designed as a pressure vessel, so that it is relatively high

Gas pressures up to 700 bar withstands. In this container wall 34 are the

aforementioned electrical connections for operating the electrolyzer 4, the inlet 22, a hydrogen port 36 and an oxygen port 38 is formed. The hydrogen connection 36 is connected to a hydrogen line 40. In correspondingly, the oxygen port 38 is connected to an oxygen line 42.

These lead to the corresponding gas connections of the fuel cell 8, the structure of which is known per se, so that further explanations are dispensable.

As a fuel cell, for example, an alkaline fuel cell

be used. In principle, it is also conceivable to design the electrolyzer as a reversible fuel cell, so that it decomposes water into hydrogen and oxygen once in the sectioned electrolysis operation and then generates the voltage U in fuel cell operation, via which a consumer or the like is driven. For example, it is possible to switch over to this fuel cell operation when the photovoltaic 16 or the others available

regenerative energy is insufficient to supply the electrical load directly.

In the embodiment according to FIG. 1, however, a separate fuel cell 8 is used. The gas flow to the fuel cell 8 is a function of the electrical power to be picked up by two control valves 44, 46 in the

Hydrogen line 40 and the oxygen line 42 set.

Both in the electrolyzer 4 and in the fuel cell 8 reaction enthalpy is released during the chemical reaction. This is - as already explained - exploited to the heat exchanger 10, a fluid, for example. A

Heat transfer medium 12 to heat. In principle, such a

Heat exchangers 10 are also connected to the electrolyzer 4 to use the reaction enthalpy released there.

In the electrolyser, the following reaction equations take place: 2 H ₂ 0 ^ 4 H ⁺ + 4 e ^" + 0 ₂

4 H ⁺ + 4 e ^" ^ 2 H ₂ Accordingly, hydrogen is formed at the cathode and oxygen at the anode. The minimum DC voltage that must be supplied by the voltage source, such as the photovoltaic, is at 1, 5 V.

In principle, instead of an alkaline electrolyzer, it is also possible to use an acidic or PEM electrolyzer, a high-temperature electrolyzer or others

Elektrolyseurbauarten be used. However, the alkaline electrolyzer described here is characterized by an extremely simple structure with very good

procedural controllability. Such electrolyzers are

For example, under the product name "Anton" offered, more

Descriptions of the structure of an electrolyzer are therefore superfluous.

Of course, other electrolytes or electrode materials can be used instead of the KOH. Another advantage of such alkaline electrolyzers is that they virtually build up the pressure in the reservoir 6 itself, so that no complex pressure control devices must be used. For safety reasons, it is preferred in the invention when the

Pressure in the memory, in particular in the hydrogen storage 28 is monitored and when a predetermined limit pressure is exceeded, a further charging of the memory 6 is no longer done and either the electrolyzer is switched off or accumulating during the electrolysis gas mixture (oxyhydrogen gas) via a non-illustrated

Burner or the like is used to heat other media or rooms.

In principle, of course, a parallel-connected gas storage (at least for hydrogen) may be present, which is then loaded at fully charged memory 6.

As indicated in Figure 1, the water volume flow in the return line 13 via a pump 48 and a controller 50 is set so that the electrolyte concentration in Electrolyzer 4 is kept constant. Excess water can be pumped into a tank or nachgefördert from a tank.

Figure 2 shows a simplified variant of an energy converter 1, the

For example, in a house or the like can be used instead of or in addition to a conventional heating.

Just as in the embodiment described above is a

Electrolyzer unit 2 with an electrolyzer 4 and a memory 6 is provided which has a hydrogen storage 28 and an oxygen storage 30 and as

Pressure vessel is formed. Electrolyzer 2 and memory 6 are in turn designed as a functional and structural unit. The working voltage UA of

In turn, electrolyzers are provided via an energy source, such as a photovoltaic element 16 powered by sunlight. The construction of the

Electrolyzer unit 2 corresponds to that of the previously described

Embodiment, so that further explanations are unnecessary.

An essential difference of the energy converter 1 according to FIG. 2 to the previously described exemplary embodiment is that the connections 36, 38 leading out of the pressure vessel 34 are brought together, whereby these

Merge can be done for example via an indicated mixing valve 50. At the output of a blast gas line 52 is connected, wherein the

Gas flow in the oxyhydrogen gas line 52 is kept constant by means of a regulator 54. The blast gas line 52 is connected to a burner unit 56 in which the high-energy blast gas is "burned." This burner unit 56 has an integrated heat exchanger, via which the reaction enthalpy released in the blast gas reaction is used to heat the heat transfer medium 12, for example heating water. This can be conveyed to the respective place of use, for example, by means of a pump 58. The water 56 produced in the oxyhydrogen gas reaction is returned to the reservoir 6 either via the already explained return 13 with pump 48 and mixing valve 50 or else

cooled water over a cold water drain 60 deducted. In principle, can Of course, the return 13 are connected to the cold water outlet 60, so that only when needed water is returned to the electrolyzer 4.

Incidentally, the exemplary embodiment according to FIG. 2 corresponds to the exemplary embodiment described above, so that further explanations are unnecessary.

As already mentioned, an energy converter according to FIG. 1 could be used to charge the accumulator in an electric vehicle. The energy to be supplied to the electrolyzer 4 could then, for example, by recuperation at

Braking the vehicle are supplied so that the memory 6 is charged in such operating conditions, so that there is always enough energy available to charge the battery.

The solution explained in FIG. 2 is intended for stationary use, for example as a heater. Of course, such a unit could also be part of an air conditioning system to a vehicle interior or a

Heat coolant circuit as quickly as possible. Such a coolant circuit is also required in electric vehicles to dissipate the waste heat or at

Cold start to bring the components to operating temperature.

Disclosed are an electrolyzer unit and an energy converter with such an electrolyzer unit. This has an electrolyzer, which forms a structural unit with a memory.

LIST OF REFERENCES:

1 energy converter

2 electrolyzer unit

4 electrolyzer

6 memory

8 fuel cell

10 heat exchangers

12 heat transfer medium 13 return

14 electrode

16 photovoltaic

18 housing plate

20 housing plate

22 inlet

24 gas outlet

26 gas outlet

28 hydrogen storage

30 oxygen storage

32 storage wall

34 container wall

36 hydrogen connection

38 oxygen connection

40 hydrogen line

42 oxygen line

44 control valve

46 control valve

48 pump

50 mixing valve

52 oxy-fuel gas line

54 controllers

56 burner unit pump

Cold water drain

Claims

claims

1. electrolysis unit for decomposing water into hydrogen and

Oxygen, with a storage for hydrogen and oxygen, thereby

characterized in that the memory (6) forms a structural unit with the electrolyzer (4).

2. electrolyzer unit according to claim 1, wherein the memory (6) is a pressure vessel, in which the electrolyzer (4) is at least partially integrated.

3. electrolyzer unit according to claim 1 or 2, wherein the hydrogen and the oxygen in each case in a hydrogen storage (28) or a

Oxygen storage (30) are arranged, which is connected to a corresponding gas outlet (24, 26) of the electrolyzer (4).

4. electrolyzer unit according to one of the preceding claims, wherein the electrolyzer (4) is an alkaline electrolyzer.

5. electrolyzer unit according to one of the preceding claims, wherein electrodes (14) of the electrolyzer (4) are stainless steel plates by means of

Plastic seals are spaced.

6. energy converter with an electrolyzer unit according to one of

previous claims, with an energy source for operating a

Electrolyzer (4) and having a cell for generating electrical, thermal and / or mechanical energy from hydrogen and oxygen.

7. energy converter according to claim 6, wherein the cell is a

Fuel cell (8) is.

8. electrolyzer unit according to claim 6, wherein the cell is a

Burner unit (56).

9. energy converter according to claim 8, wherein the burner unit (56) has a heat exchanger for heat exchange with a heat transfer medium (12).

10. Energy converter according to one of the claims 6 to 9, with a

Return (13) for water to the electrolyzer (4).

11. Energy converter according to one of the claims 6 to 10, wherein the energy source is operated by solar energy, wind, water energy or by kinetic energy of a utility device, such as a vehicle or an elevator.

12. Energy converter according to one of the preceding claims, wherein this is associated with an electric motor or a battery of an electric motor.