METAL AIR BATTERY

Abstract

A metal-air battery may include a housing, at least one hollow-cylindrical cathode arranged in the housing between an air chamber and an electrolyte chamber, and at least one metallic anode arranged in the electrolyte chamber. The battery may also include an air path leading through the housing from an air inlet to an air outlet of the housing, both of which may be fluidically connected to the air chamber, and an air supply device for generating an air flow following the air path and impinging on the cathode. The battery may further include an electrolyte path leading through the housing from an electrolyte inlet to an electrolyte outlet of the housing, both of which may be fluidically connected to the electrolyte chamber, and an electrolyte supply device for generating an electrolyte flow following the electrolyte path and impinging on the anode and the cathode.

Claims

1. A metal-air battery, with a housing (2), with at least one hollow-cylindrical cathode (7), which is arranged in the housing (2) between an air chamber (9) and an electrolyte chamber (10), with at least one metallic anode (11), which is arranged in the electrolyte chamber (10), with an air path (14) leading through the housing (2), which leads from an air inlet (15) of the housing (2), which is fluidically connected to the air chamber (9), to an air outlet (16) of the housing (2), which is fluidically connected to the air chamber (9), with an air supply device (20) for generating an air flow following the air path (14) impinging on the cathode (7), with an electrolyte path (17) leading through the housing (2), which leads from an electrolyte inlet (18) of the housing (2), which is fluidically connected to the electrolyte chamber (10), to an electrolyte outlet (19) of the housing (2), which is fluidically connected to the electrolyte chamber (10), with an electrolyte supply device (21) for generating an electrolyte flow following the electrolyte path (17) impinging on the anode (11) and the cathode (7).

2. The battery according to claim 1, characterized by a control device (22) for operating the metal-air battery (1), which is electrically connected to the air supply device (20) and to the electrolyte supply device (21), wherein the control device (22) is configured and/or programmed so that as a function of a current electric power demand on the metal-air battery (1) it activates the air supply device (20) for generating an air flow adapted to this power demand and/or activates the electrolyte supply device (21) for generating an electrolyte flow adapted to this power demand.

3. The battery according to claim 2, characterized in that the control device (22) is configured and/or programmed so that as a function of the current power demand it activates the electrolyte supply device (21) for generating the electrolyte flow adapted to this power demand and activates the air supply device (20) for generating an air flow adapted to the adapted electrolyte flow.

4. The battery according to claim 2 or 3, characterized in that the control device (22) is configured and/or programmed so that for switching off the metal-air battery (1) it activates the electrolyte supply device (21) for draining the electrolyte path (17) of electrolyte.

5. The battery according to any one of the claims 1 to 4, characterized in that the anode (11) is rotatably mounted on the housing (2) about its longitudinal centre axis (13).

6. The battery according to claim 5, characterized in that a rotary drive (56) for rotationally driving the anode (11) is provided.

7. The battery according to claim 6, characterized in that the anode (11) is configured so that a rotation of the anode (11) drives the electrolyte in the electrolyte path (17).

8. The battery according to claim 7, characterized in that the anode (11) on its outside (36) exposed to the electrolyte chamber (10) comprises flow guiding structures (37) which with rotating anode (11) drive the electrolyte.

9. The battery according to claim 5, characterized in that the electrolyte path (17) is conducted past the anode (11) so that the electrolyte flow rotatingly drives the anode (11).

10. The battery according to claim 9, characterized in that the electrolyte inlet (18) on a first end region of the electrolyte chamber (10) is arranged tangentially to the electrolyte chamber (10), while the electrolyte outlet (19) is arranged on a second end region of the electrolyte chamber (10).

11. The battery according to claim 9 or 10, characterized in that the anode (11) on its outside (36) exposed to the electrolyte chamber (10) comprises flow guiding structures (37) which transmit a torque to the anode (11) when the anode (11) is impinged by the electrolyte flow.

12. The battery according to any one of the claims 1 to 11, characterized in that the anode (11) is configured cylindrically and mechanically and electrically connected to a metallic support plate (26).

13. The battery according to claim 12, characterized in that the support plate (26) via an axial bearing (27) is rotatably mounted on the housing (2) about a longitudinal centre axis (13) of the anode (11).

14. The battery according to claim 13, characterized in that a power connection (29) of the metal-air battery (1) on the anode side is formed on the axial bearing (27).

15. The battery according to claim 13 or 14, characterized in that the axial bearing (27) comprises an anti-friction metal ring (31) which lies in an annular bearing shell (32) on the housing side and on which the support plate (26) is supported and on which the support plate (26) slides with rotating anode (11).

16. The battery according to claim 15, characterized in that the anti-friction metal ring (31) comprises an annular body (34) of an anti-friction metal alloy and at least one heating conductor (35) arranged in the annular body (34), with which the annular body (34) can be heated.

17. The battery according to claim 16, characterized in that a power supply of the heating conductor (35) is configured so that the heating conductor (35) heats the annular body (34) to a predetermined operating temperature which is below a melting point of the anti-friction metal alloy but is so close to the melting point of the anti-friction metal alloy that surface melting occurs on the annular body (34).

18. The battery according to any one of the claims 1 to 17, characterized in that the air supply device (20) upstream of the air inlet (15) comprises a concentration device (38) which increases the oxygen proportion in the air flow.

19. The battery according to any one of the claims 1 to 18, characterized in that the electrolyte supply device (21) comprises an electrolyte circuit (41) which has an advance (42), which leads from an electrolyte tank (44) to the electrolyte inlet (18), and comprises a return (43), which leads from the electrolyte outlet (19) to the electrolyte tank (44).

20. The battery according to claim 19, characterized in that in the advance (42) an advance pump (45) for driving the electrolyte is arranged.

21. The battery according to claim 19 or 20, characterized in that in the return (43) a return pump (46) for driving the electrolyte is arranged.

22. The battery according to any one of the claims 19 to 21, characterized in that in the return (43) an electrolyte cleaning device (47) for removing reaction products from the electrolyte is arranged.

23. The battery according to any one of the claims 19 to 22, characterized in that in the return (43) a gas separation device (48) for removing gases from the liquid electrolyte is arranged.

24. The battery according to claim 23, characterized in that the gas separation device (48) by way of a gas line (49) is fluidically connected to a conversion device (50) for converting the chemical energy of the separated gas into electric and/or thermal energy.

25. The battery according to claim 24, characterized in that the conversion device (50) is a catalytic burner.

26. The battery according to claim 24, characterized in that the conversion device (50) is a hydrogen-air fuel cell.

27. The battery according to any one of the claims 1 to 26, Characterized in that the air inlet (15) is arranged tangentially to the air chamber (9) and/or in that the air outlet (16) is arranged tangentially to the air chamber (9).

29. The battery according to any one of the claims 1 to 27, characterized in that an induction heating (52) for heating the anode (11) is provided.

30. The battery according to claim 28, characterized in that the induction heating (52) is arranged in the region of the cathode (7).

31. A battery system with a plurality of metal-air batteries (1) according to any one of the claims 1 to 29, characterized by a common air supply device (20) for generating the respective air flow through the air paths (14) of the batteries (1) and/or by a common electrolyte supply device (21) for generating the respective electrolyte flow through the electrolyte paths (17) of the batteries (1) and/or by a common control device (22) for operating the batteries (1).

32. A vehicle with electromotoric drive and with at least one metal-air battery (1) according to any one of the claims 1 to 29 or with a battery system (57) according to claim 30, wherein a power electronic system for the power supply of the electric drive of the vehicle is coupled in an unbuffered manner to the respective metal-air battery (1) or to the battery system (57).

33. A method for operating a metal-air battery (1) according to any one of the claims 1 to 29, in which dependent on a current power demand on the metal-air battery (1) an electrolyte flow suitable for this and/or an air flow suitable for this is/are generated.

34. The method according to claim 32, characterized in that for adapting the electrolyte flow of at least one electrolyte delivery device (45, 46; 11) is suitably activated for increasing or reducing its delivery output, and/or in that for adapting the air flow at least one air delivery device (40) is suitably activated for increasing or for reducing its delivery output.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] It shows, in each case schematically,

[0067] FIG. 1 a greatly simplified diagram representation in the manner of a circuit diagram of a metal-air battery without peripheral components,

[0068] FIG. 2 a view as in FIG. 1, however with peripheral components.

DETAILED DESCRIPTION

[0069] Corresponding to the FIGS. 1 and 2, a metal-air battery 1, which is preferably an aluminium air battery, comprises a housing 2, which is electrically insulated and preferably consists of an electrically insulating material, for example of plastic. The housing 2 in the shown example is configured as a cylindrical container and comprises a cylindrical shell 3 and a plate-shaped, in particular circular, bottom 4. In the installation state or operationally ready state of the metal-air battery 1, which in the following can also be described abbreviated as battery 1, the housing 2 is arranged so that a longitudinal centre axis 5 of the housing 2 is substantially orientated vertically, i.e. substantially parallel to the direction of gravity 6, which in FIG. 1 is indicated by an arrow. The battery 1 furthermore comprises at least one hollow-cylindrical cathode 7, which is arranged in the housing namely preferentially so that in the operationally ready state of the battery 1 a longitudinal centre axis 8 of the cathode 7 substantially runs parallel to the direction of gravity 6. In the shown example, the housing 2 and the cathode 7 are arranged coaxially and concentrically to one another so that the two longitudinal centre axes 5, 8 coincide. The cathode 7 separates in the housing 2 an air chamber 9 from an electrolyte chamber 10. The cathode 7 consists in the usual manner of a porous material, as a result of which a large surface area is made available to the generally liquid electrolyte, which makes possible contacting with the gaseous oxygen contained in the air. For example, the cathode can be formed of a permeable membrane or comprise such.

[0070] Furthermore, the battery 1 comprises at least one metallic anode 11, which is arranged in the electrolyte chamber 10. In the example, the anode 11 has a cylindrical anode body 12 with a longitudinal centre axis 13 and is arranged coaxially to the cathode 7 and in particular concentrically thereto. Accordingly, the longitudinal centre axes 5, 8, 13 coincide here.

[0071] An air path 14, which is indicated by arrows in FIG. 1 and which in the housing 2 fluidically connects an air inlet 15 of the housing 2 passing through the air chamber 9 to an air outlet 16 of the housing, leads through the housing 2. In addition, an electrolyte path 17 leads through the housing 2, which is indicator arrows in FIG. 1 and which fluidically connects an electrolyte inlet 18 of the housing 2 passing through the electrolyte chamber 10 to an electrolyte outlet 19 of the housing 2.

[0072] In addition, the battery 1 is equipped with an air supply device 20, with the help of which for the operation of the battery 1 an air flow can be generated, which during the operation of battery 1 follows the air path 14 and thereby impinges, i.e. flows onto or circulates around the cathode 7. In addition, an electrolyte supply device 21 is provided, with the help of which during the operation of the battery 1 an electrolyte flow can be generated, which during the operation of the battery 1 follows the electrolyte path 17 and thereby impinges, i.e. flows onto or circulates about the anode 11 and on the other hand the cathode 7.

[0073] For operating the battery 1, a control device 22 is provided according to FIG. 2, for example in the form of a control unit. The control device 22 is electrically connected to the air supply device 20 and to the electrolyte supply device 21, for example by way of suitable control lines 23. The control device 22 can be additionally electrically connected via suitable signal lines 24 to a sensor system of the battery 1 which is not shown in more detail here. Provided that the battery 1 is employed in a primary system, in particular in a vehicle, for providing electric energy, the control device 22 is additionally connected via such a control line 24 to a control of the system or of the vehicle which is not shown here, so that the control device 22 knows the current electric power requirement of the system, respectively of the vehicle. This current power requirement corresponds to a current power demand to the battery 1.

[0074] The control device 22 is now configured or programmed so that it activates the air supply device 20 and/or the electrolyte supply device 21 dependent on the current electric power demand to the battery 1 in such a manner that the air supply device 20 generates an air flow that is adapted to the current power demand and/or that the electrolyte supply device 21 generates an electrolyte flow that is adapted to the current power demand. Preferentially, the configuration or programming of the control device 22 takes place in such a manner that it initially, dependent on the current power demand, determines in a first step an electrolyte flow to suit said power demand, for example by way of characteristic curves or characteristic maps or by way of suitable calculation formula, and then activates the electrolyte supply device 21 so that the same generates the determined electrolyte flow. In a second step, which can take place quasi in parallel, the control device 22 can determine an air flow that is required for the determined electrolyte flow, likewise by way of characteristic curves or characteristic maps or by means of suitable calculation formulae, so that it can subsequently activate the air supply device 20 for generating the determined air flow.

[0075] The control device 22 thus makes possible a hydraulic or hydropneumatic open-loop or closed-loop power control of the battery 1. When the power demand increases, the volumetric flows for electrolyte and air are suitably increased. When by contrast the power demand decreases, the volumetric flows for electrolyte and air are suitably reduced. Accordingly, the wear of the battery 1, i.e. the dissolution of the anode 11, is minimised. Because of this, the battery 1 has a comparatively long life span.

[0076] In addition, the control device 22 can be programmed or configured so that it activates the electrolyte supply device 21 for example for switching off the battery 1 so that it drains the electrolyte chamber 10 or the entire electrolyte path 17 of electrolyte. This can be additionally followed by a flushing with a suitable neutral or inert flushing medium.

[0077] As is evident in particular from FIG. 1, the anode 11, according to a preferred embodiment, can be rotatably mounted on the housing 2 about its longitudinal centre axis 13. A corresponding rotary movement is indicated in the figures by a rotary arrow 25. Through the rotary movement of the anode 11, the contact between anode 11 and electrolyte is improved, which improves the electrolytic reaction for current generation. At the same time, the rotation of the anode 11 at suitable rotational speeds can generate centrifugal forces which can cause reaction products to be detached from the anode 11, which likewise improves the efficiency of the electrolyte reaction. The anode 11 or its anode body 12 is arranged on a metallic support plate 26 and mechanically and electrically connected to the same. In this regard, the support plate 26 can also be counted as part of the scope of the anode 11. The support plate 26 is rotatably mounted about the longitudinal centre axis 13 of the anode 11 via an axial bearing 27 on the housing 2. The axial bearing 27 to this end is arranged on a face end 28 of the housing shell 3 facing away from the bottom 4.

[0078] The battery 1 comprises two galvanic or electric power connections 29, 30, namely a first electrical power connection 29, which represents a negative terminal that is electrically connected to the anode 11, and a second electrical power connection 30, which represents a positive terminal that is electrically connected to the cathode 7.

[0079] In the preferred example shown here, the galvanic power connection 29 on the anode side is formed on the axial bearing 27 or connected to the same in a fixed manner, as a result of which it is fixed in location with respect to the housing 2 and in contrast with the non-stationary or rotating anode 11, arranged stationarily or rotationally fixed.

[0080] The axial bearing 27 can be configured as a rolling bearing in principle. However, preferred is the shown embodiment in which the axial bearing 27 is configured as sliding bearing. In particular, the axial bearing 27 to this end can comprise a anti-friction metal ring 31 and an annular bearing shell 32. The bearing shell 32 is arranged fixed on the housing 2. The anti-friction metal ring 31 is inserted in the bearing shell 32. To this end, the bearing shell 32 in the example comprises an axially open annular groove 33. The anti-friction metal ring 31 lies in the annular groove 33. The support plate 26 is supported on the anti-friction metal ring 31 and can slide thereon during the operation of the battery 1. The anti-friction metal ring 31 comprises an annular body 34, which consists of an anti-friction metal alloy, and at least one metallic heating conductor 35, which is arranged in the annular body 34. With the help of the heating conductor 35, the annular body 34 can be heated. A power supply of the heating conductor 35 which is not shown here can be configured so that the heating conductor 35 heats the annular body 34 to a predetermined operating temperature, which on the one hand lies below a melting point of the anti-friction metal alloy and which on the other hand however is so close to the melting point of the anti-friction metal alloy that surface melting occurs on the annular body 34. For example, the operating temperature is approximately 10% to 20% below the melting temperature of the anti-friction metal alloy. As anti-friction metal alloy, a low-melting alloy is practically used, which can have a maximum melting point of 250 C. to 350 C. By heating up the annular body 34 to the predetermined operating temperature, said surface melting on the annular body 34 occurs, so that a surface of the annular body 34 located outside is liquefied at least in the region of the support plate 26. On the one hand, this produces an extremely low-friction hydraulic sliding mounting. On the other hand, this significantly improves the electrical contact between anti-friction metal ring 31 and support plate 26, as a result of which large currents can be transmitted with low voltages.

[0081] The power supply of the heating conductor 35 mentioned above can be realised by a separate power supply which can be open-loop or closed-loop controlled with the help of the control device 22 for example in conjunction with a temperature sensor, in order to adjust the desired operating temperature on the annular body 34. In a simplified case, the power supply can also be realised with the help of at least one PTC element, which is connected in series with the heating conductor 35 in a suitable location. It is conceivable, in particular, to introduce the heating conductor 35 into a current path between the support plate 26 and the axial bearing 32, if required including the respective PTC element.

[0082] According to another advantageous embodiment, which is likewise shown here, the electrolyte path 17 is conducted past the anode 11 or the anode body 12 so that the electrolyte flow during the operation of the battery 1 rotatingly drives the rotatably mounted anode 11. To this end, the electrolyte inlet 18 can be arranged tangentially to the electrolyte chamber 10. Accordingly, the inflow of electrolyte into the electrolyte chamber 17 takes place near the cathode 7. Furthermore it can be provided that the electrolyte inlet 18 is arranged on a first end region of the electrolyte chamber 10, here distally to the bottom 4 or in the installation state at the top, while the electrolyte outlet 19 is arranged on a second end region of the electrolyte chamber 10, which is distant from the first end region. In the example of FIG. 1 or in the installation state, the electrolyte outlet 19 is arranged proximally to the bottom 4, i.e. at the bottom. In the shown example, the electrolyte outlet 19 is additionally orientated axially and passed through the bottom 4. The arrangement of electrolyte inlet 18 and electrolyte outlet 19 at opposite axial ends of the electrolyte chamber 10 brings about an axial through-flow of the electrolyte chamber 10 with electrolyte. The tangential arrangement of the electrolyte inlet 18 generates in the electrolyte chamber 10 a swirling flow or helical flow, which even because of frictional effects rotatingly drives the anode 11. The swirling flow in the electrolyte chamber 10 however also makes possible comparatively high flow velocities with a comparatively large dwell duration for the electrolyte in the electrolyte chamber 10.

[0083] In the example, the anode 11 or the anode body 12 is equipped, on an outside 36 exposed to the electrolyte chamber 10, with flow guiding structures 37. Here, the flow guiding structures 37 are configured so that they can transmit a torque to the anode 11 when the anode 11 is impinged by the electrolyte flow. The flow guiding structures 37 can thus utilise kinetic energy of the electrolyte flow for driving the anode 11. The flow guiding structures 37 can be formed for example by helical blades or blade sections. The flow guiding structures 37 are provided cumulatively to the tangential electrolyte inlet 18 here, but can also be provided alternatively thereto.

[0084] While with the example described above the electrolyte flow, which is generated in a suitable manner, is utilised for rotatingly driving the anode 11, it can be provided, according to another embodiment, to use the rotation of the anode 11 for driving the electrolyte, i.e. for generating the electrolyte flow. To this end, a rotary drive 26 which is indicated with interrupted line in FIG. 2 can be provided, which rotatingly drives the anode 11. In the example, the rotary drive 56, which can for example be an electric motor, drives the support plate 26, which supports the anode body 12. In this case, the flow guiding structures 37 operate like moving blades of an axial flow machine for example as with a propeller. The driven anode 11 in this case forms an electrolyte delivery device. The control device 22 can be electrically connected to the rotary drive 56 via a suitable control line 23, in order to be able to activate the rotary drive 56 depending on demand.

[0085] According to FIG. 2, the air supply device 20 can comprise a concentration device 38 upstream of the air inlet 15, with the help of which the oxygen proportion in the air flow can be increased. The concentration device 38 can operate by means of suitable filter structures, in particular membranes and the like. Accordingly, the air flow downstream of the concentration device 38 has a significantly elevated oxygen proportion compared with the air flow upstream of the concentration device 38. By way of a waste air line 39, an air flow with suitably reduced oxygen proportion or elevated nitrogen proportion can be discharged from the concentration device 38. The air supply device 20 in this case additionally comprises a blower 40 for driving or generating the air flow. The blower 40 can be activated by the control device 22. In addition, a normal air filter which is not shown here can be included in the air supply device 20, with which liquid and/or solid contaminations can be filtered out of the air.

[0086] The electrolyte supply device 21 according to FIG. 2 is equipped with a closed electrolyte circuit 41, which comprises an advance 42 and a return 43. The advance 42 fluidically connects an electrolyte tank 44 for storage of the electrolyte through the electrolyte inlet 18. In the advance 42, an advance pump 45 is arranged, which can be activated with the help of the control device 22. The return 43 fluidically connects the electrolyte outlet 19 to the electrolyte tank 44 and contains a return pump 46, which can be activated with the help of the control device 22. Advance pump 45 and return pump 46 in this case form electrolyte delivery devices.

[0087] In the return 43, an electrolyte cleaning device 47 is additionally arranged downstream of the return pump 46, with the help of which reaction products can be removed from the electrolyte. Thus, conditioning of the electrolyte takes place within the electrolyte cleaning device 47 so that cleaned or unconsumed electrolyte can be fed to the electrolyte tank 44. The electrolyte cleaning device 47 can be configured for example as a centrifuge, in particular with a membrane. Here, the centrifuge can be configured as a return jet centrifuge, which is driven by the kinetic energy of the electrolyte flow.

[0088] In the return 43, a gas separation device 48 can be additionally arranged, with the help of which gases can be separated from the liquid electrolyte. In the example, the gas separation device 48 is arranged downstream of the return pump 46 or downstream of the electrolyte cleaning device 47. The separated gas is in particular hydrogen gas, which is generated during the electrolyte reaction in the electrolyte chamber 10. The gas separation device 48 can comprise a plurality of nozzles for the improved gas separation, through which the liquid electrolyte is pressed. It has been shown that the nozzles amplify a bubble formation which simplifies the separation of the gas from the liquid electrolyte.

[0089] The gas separation device 48 is fluidically connected via a gas line 49, to a conversion device 50 with the help of which the chemical energy of the separated gas can be converted into electric and/or thermal energy. The conversion device 50 for example is a catalytic burner so that the combustible gases can be exothermically converted in order to generate heat. Alternatively, the conversion device 50 can be a hydrogen-air fuel cell, which converts the separated hydrogen gas into heat and electric energy with the help of air oxygen. The energy converted with the help of the conversion device 50 from the separated gases can be fed, according to an arrow 51, to the battery 1 or the respective primary system, i.e. in particular the vehicle.

[0090] Furthermore, a heat exchanger 55 can be arranged in the return 43, with the help of which the returned electrolyte can be cooled. The heat discharged in the process can either be fed to the reaction zone within the electrolyte chamber 10 or the primary system of the battery 1, in particular the vehicle. In the example of FIG. 2, the heat exchanger 55 is integrated in the gas separation device 48.

[0091] According to FIG. 1, it can be provided to arrange at least the air inlet 15 tangentially to the air chamber 9 for increasing a dwell duration of the air flow in the air chamber 9. Furthermore, air inlet 15 and air outlet 16 are arranged at ends of the air chamber 9 that are distant from one another. Here, an arrangement that is inverted compared with the electrolyte path 17 is preferred so that for the electrolyte path 17 and the air path 14 the so-called counter-flow principle can be realised. Accordingly, the air inlet 15 in the example is arranged proximally to the bottom 4 while the air outlet 16 is arranged distally to the bottom 4.

[0092] For heating the anode 11 or the anode body 12, an induction heating 57 can be provided, which is arranged for example in the region of the cathode 7. With the help of the induction heating 52, the anode 11 or the anode body 12 can be contactlessly heated while on the other hand, heating specifically takes place in the region of the outside 36 facing the electrolyte chamber 10, which is also exposed to the electrolyte flow. Thus, heating takes place specifically where an increased temperature for improved electrolyte reaction is desirable. The induction heating 52 is configured in particular so that a standing electromagnetic field with magnetic polarisation alternating in the circumferential direction is generated, which takes place by induction only upon a relative movement of the anode 11 for the desired surface heating of the anode 11 or of the anode body 12. The relative movement of the anode 11 in this case is effected through the rotation of the anode 11 about its longitudinal centre axis 13. The inductive heating is rotational speed controlled, the rotational speed of the anode 11 depending on the volumetric flow of the electrolyte.

[0093] Although in the preferred example shown here only a single cathode 7 and only a single anode 11 are arranged in the housing 2, it can be provided in another embodiment to arrange a plurality of cathodes 7 and a plurality of anodes 11 in the same housing 2. It is likewise conceivable to arrange a plurality of anodes 11 in the same cathode 7.

[0094] A battery system which is globally designated 57 in FIG. 2 comprises at least two metal-air batteries 1 of the type described above, wherein however the peripheral units or components can be jointly utilised. For example, a plurality of batteries 1 can be supplied with the respective air flow by a common air supply device 20. Furthermore, a plurality of batteries 1 can be supplied with the respective electrolyte flow by a common electrolyte supply device 21. In particular, a common control device 22 can be used in order to operate a plurality of batteries 1 or the battery system 57. In particular, common delivery devices for generating the air flows or electrolyte flows for the individual batteries 1 can also be used. The batteries 1 can be connected electrically in series or in parallel. Independently of this, the electrolyte paths 17 of the batteries 1 can be arranged fluidically in parallel or in series. For example, a common electrolyte circuit 41 can be provided, into which a plurality of batteries 1 is fluidically incorporated, so that further components of the electrolyte circuit 41 can be jointly utilised, such as for example the electrolyte cleaning device 47 and/or the gas separation device 48. Likewise, the air paths 14 of the batteries 1 can be arranged fluidically in parallel or in series, wherein further components of the air supply device 20 can also be jointly utilised here, such as for example the concentration device 38 or an air filter.

[0095] A vehicle, which has an electromotoric drive, can be equipped with at least one battery of the type described above or with a battery system 57 described above, in order to provide electric energy for the respective electric motor. It is particularly advantageous that the battery 1 introduced here can be electrically connected, because of their hydraulic or hydropneumatic open-loop or closed-loop power control, unbuffered in principle, to the respective current consumer of the vehicle or to a corresponding power electronic system so that in particular heavy accumulators and the like can be omitted.

[0096] For operating such a metal-air battery 1 or such a battery system 57 it can be now be provided that dependent on a current power demand on the metal-air battery 1 or on the battery system 57 an electrolyte flow suitable for this purpose and/or an air flow suitable for this purpose is/are generated for the respective battery 1. Practically it can be provided to this end that for adapting the electrolyte flow the respective electrolyte delivery device, i.e. preferentially the electrolyte pumps 47, 46 for the rotatingly driven anode 11, is suitably activated for increasing or reducing their delivery output and/or that for adapting the air flow the respective air delivery device, i.e. preferentially the blower 40, is suitably activated for increasing or reducing its delivery output.

[0097] According to FIG. 1 and according to a particularly advantageous embodiment the anode 11 can be produced so that its anode body 12 comprises a matrix 53 of sodium, into which the particles 54 of an aluminium alloy are embedded. Consequently, this is not an aluminium-sodium alloy but an aluminium-sodium composite material. This is achieved in that a granulate of the aluminium alloy, which forms the particles 54, is introduced into a melt of sodium, which in the process forms the matrix 53. With the help of this sodium melt, which contains the particles 54 of the aluminium alloy, the anode 11 or the anode body 12 can be cast.

[0098] The particles 54 can for example have a particle size of 10 m to 100 m. Preferred is a particle size of 40 m to 60 m. Particularly preferred is a particle size of approximately 50 m. The proportion of the particles 54 in the anode body 12 is preferentially in a range from 40% to 80%. Advantageous is a particle proportion of 60% to 70%. Particularly preferable is a particle proportion of approximately 65%, expressed as percent by weight.

[0099] The aluminium from which the particles 54 are produced, can contain zirconium according to an advantageous embodiment. It has been shown that zirconium in the aluminium alloy reduces the formation of a barrier layer on the outside 36 of the anode body 12 just so far that a direct conversion of aluminium with water into aluminium oxide and hydrogen is largely prevented. Preferably, the aluminium alloy contains 0.01% to 1.00% zirconium. Preferred is a zirconium proportion of 0.05% to 0.8%. Particularly advantageous is a zirconium proportion of approximately 0.5%. The above percentage information is expressed as percent by weight. The aluminium alloy otherwise consists exclusively of aluminium except for unavoidable contaminations due to the production.

[0100] The electrolyte preferably employed here consists of an aqueous acid or an aqueous alkaline solution, to which is added at least one halogen and at least one tenside. Halogens are fluorine, chlorine, bromium, iodine, astate and ununseptium. Possible for the electrolyte are especially fluorine, chlorine, bromium and iodine. Preferred in this case is fluorine. Here, the halogens are not employed in the pure form but in the form of fluoro compounds, in particular in the form of salts containing fluorine, so-called fluorides. Tensides are substances which lower the surface tension of a liquid or the interfacial tension between two phases and make possible or promote the formation of dispersions or acts as solubilizer.

[0101] The acid or alkaline solution used for the electrolyte has a concentration in water of 10% to 40%. Preferred here is a concentration in the range from 15% to 25%. Particularly advantageous is a concentration of approximately 20%. Within the acid or alkaline solution, the halogen has a proportion of 0.1% to 4.0%. Preferred is a halogen proportion of 0.5% to 2.0%. A preferred halogen in this case is potassium aluminium pentafluoride. The tenside in the acid or alkaline solution has a proportion of 0.1% to 2.0%. Preferred is a tenside proportion of 0.2% to 1.0%. Sodium Lauryl Sulfate is preferred as tenside. The above percentage information is expressed as percent by weight in each case.