Recombination system with a recombination device

Abstract

Recombination system (10) with a recombination device (20) for the catalytic recombination of hydrogen and oxygen produced in accumulators to form water, wherein the recombination device (20) comprises at least in a partial area at least a catalyst material (150) which has at least a partial area above a center line of the recombination device (20) with respect to a position of a support (90) of the recombination system (10) for the recombination device (20) a first subset (230) of the catalyst material (150), wherein the first subset (230) is larger than a second subset (240) of the catalyst material (150) which is located from the center line of the recombination device (20) in the direction of the support (90), characterized in that the support (90) is arranged in a ceiling area (60) of the recombination system (10).

Description

[0001] The invention relates to a recombination system with a recombination device for the catalytic recombination of hydrogen and oxygen produced in accumulators to form water, wherein the recombination device comprises at least one catalyst material in at least one partial area.

[0002] Accumulators are widely used and serve as rechargeable electrochemical storage devices for electrical energy. The application spectrum of lead-acid technology is very broad, ranging from simple starter batteries for on-board power systems and starter motor batteries to uninterruptible power supplies in standby parallel operation for grid failures, in photovoltaic systems, and in traction systems for industrial trucks in cyclic operation.

[0003] A characteristic of sealed lead-acid batteries is water loss. Due to their electrochemical properties, the water in the battery's electrolyte decomposes into oxygen and hydrogen, causing the electrolyte level in the individual sealed cells to drop. Ventilation of the battery compartment is mandatory. Water decomposition occurs, on the one hand, due to the low decomposition voltage of water (1.223 V water decomposition voltage). On the other hand, electrolysis in the lead-acid battery leads to water decomposition and the rising of gas bubbles when the gassing voltage exceeds 2.40 V per cell.

[0004] This produces hydrogen at the negative electrode, which is a flammable gas but does not support combustion. At the positive electrode, oxygen is formed in a stoichiometric ratio of 1:2. Due to the low solubility of both gases in the electrolyte, these gas bubbles escape from the system through the filler and degassing plugs.

[0005] Both inside and outside the battery body, the two gases can recombine. Even at room temperature, oxygen and hydrogen combine to form water. However, this occurs at such a slow, barely measurable rate that a hydrogen-oxygen mixture can be stored for months without any conversion being detectable.

[0006] Overall, the disadvantages of water decomposition in battery technologies with aqueous electrolyte, including lead-acid batteries, were recognized very early on (for example, by Mr. Edison in 1904), and attempts were made to compensate for these disadvantages over various development stages.

[0007] It has been discovered that the acceleration of the recombination process of hydrogen and oxygen gas occurs with the help of catalysts. Generally speaking, catalysts are substances that can increase or decrease the rate of a chemical reaction. Since they are not consumed in the process, catalysts remain unchanged at the end of the reaction and thus do not appear in the reaction equations for the conversion. The acceleration is achieved by lowering the activation energy. This allows the inhibited reaction of oxygen and hydrogen to be accelerated.

[0008] The freely moving hydrogen molecules contact the surface of the catalyst material. Freely moving electrons attached there cause the bonds to break, bonding with the individual hydrogen atoms and allowing them to move freely across the surface. The oxygen molecules, also freely moving, land on the platinum surface and, as individual atoms, form a bond with two hydrogen atoms each. As a result, two water molecules are formed from one oxygen molecule and two hydrogen molecules through recombination.

[0009] When oxygen and hydrogen combine back to form water, energy is released, which is expressed as a high heat evolution (193 kJ / mol), allowing the water molecules to leave the platinum catalyst. The separated substances are reunited through recombination with the help of a catalyst.

[0010] This effect has also been used to develop external catalytic plugs for recombination. When using the recombination system, the hydrogen and oxygen gases produced during the decomposition of water in the battery are fed into the recombiner, which is mounted on the opening of the lead-acid battery.

[0011] Using an integrated precious metal catalyst contained in a gas-permeable ceramic, these gases are recombined, producing water vapor. The water vapor condenses on the walls of the plug. The resulting water droplets flow downward and are returned to the battery.

[0012] As already mentioned, the recombination of hydrogen and oxygen is an exothermic process in which heat is released.

[0013] The recombiner is installed as an external component on the opening of, for example, the battery cap. What all these recombination plugs have in common is that, depending on the availability of the reactants oxygen and hydrogen and the amount of catalyst, the gas-permeable ceramic heats up considerably.

[0014] The major challenge lies in managing this heat in the plug, as the gas-permeable ceramic is usually fixed at one or more points. Typically, the active element is secured either on two sides in a holder, as is already known from many inventions, or on one side. A uniform distribution of the catalyst material (e.g., palladium-coated ceramic oxide) can lead to significant heating of the support tube, thereby rendering the support / holder thermally unstable. On the other hand, the catalyst content cannot be reduced, as it is a certain minimum amount that ensures recombination with sufficient efficiency with an appropriate supply of oxygen and hydrogen gas.This raises the question of how the thermal load on the carrier can be reduced without reducing the efficiency of recombination and yet preventing overheating of the system.

[0015] Various approaches are known from the state of the art, which only partially relate directly to the above-mentioned question.

[0016] For example, a gas recombiner is known from EP 1 780 826 B1. To prevent efficiency from decreasing during operation due to possible overpressure or underpressure, appropriate pressure and vacuum relief valves are provided. Overpressure, in particular, can be associated with increased temperature. The recombination device is positioned at the lower end of the housing by means of two centering elements, thus ensuring direct contact with the lower end of the housing. Any process heat generated can thus be transferred unhindered from the recombination device to the supporting elements.

[0017] From the publication WO 200 60 48 072 A1, a recombiner with a recombination device for the catalytic recombination of hydrogen and oxygen in accumulators to form water is known. To prevent the recombination device from becoming saturated due to the dripping of water condensed on the inner wall of the container, the recombination device is provided with a sieve element. Therefore, while improved process control with the goal of improved efficiency plays a role in this solution, the problem of generated process heat is not the focus here, and the solution provides at most a subordinate aspect for dealing with generated process heat.

[0018] EP 1 674 424 A1 discloses a recombination device for the catalytic recombination of hydrogen occurring in energy storage devices. The recombination device is formed by modular recombination elements that can be combined with one another and are arranged on a base in the base region of a recombination system with an absorber interposed.

[0019] The invention is based on the object of providing a recombination system which ensures improved thermal management during operation with regard to process heat occurring.

[0020] According to the invention, a recombination system is provided with a recombination device for the catalytic recombination of hydrogen and oxygen produced in accumulators to form water, wherein the recombination device comprises at least one catalyst material in at least one partial region. The at least one partial region above a center line of the recombination device relative to a position of a holder of the recombination system for the recombination device has a first partial amount of the catalyst material, wherein the first partial amount is larger than a second partial amount of the catalyst material, which is located starting from the center line of the recombination device in the direction of the holder.This makes it easier to counteract any process heat that occurs and reduces thermal stress, particularly on the holder, which can also be referred to as the carrier, without reducing the efficiency of recombination and yet still preventing overheating of the system. Due to the asymmetrical use of the catalyst, which can be provided in a tube, for example, the temperature on the attached side of the recombination device, which can comprise a ceramic, for example, is significantly reduced. By increasing the distance to the attachment with the appropriate length of the recombination device, for example in the form of a ceramic tube, the recombination mass is oriented on one side away from the attachment base or the holder, so that the thermal stress on the attachment is significantly reduced.The catalyst, for example in the form of spheres or rods, is then arranged on one side, and the temperature at the mount drops. Corresponding tests with the same amount of catalyst and the various arrangements show a significant reduction in the thermal load on the mount or mount. Thus, using the presented system, it is possible to achieve lower overheating of the mount or mount for the recombination device, for example, comprising a gas-permeable ceramic with an integrated precious metal catalyst, while maintaining the overall height of the recombination device, for example, comprising a ceramic tube, and maintaining a constant circumference of the catalyst material.In this respect, the amount of catalyst remains identical to other arrangements, and only an asymmetrical arrangement of the catalyst in the recombination device, for example, comprising a gas-permeable ceramic, achieves this technical effect of improved thermal management. A position of the holder is to be understood as a reference point, such that the first subset of the catalyst material is located above a centerline of the recombination device or is located substantially opposite the holder. In other words, the first subset is provided starting from the position above a centerline of the recombination device.

[0021] According to the invention, it is further provided that the holder is arranged in a ceiling region of the recombination system. In this case, a major portion of the catalyst or a first portion of the catalyst is arranged below a center line of the recombination device with respect to an installation direction of the recombination device, so that the aforementioned advantages are achieved accordingly. Furthermore, in this case, it is additionally possible to prevent condensation from dripping onto the recombination device and the efficiency of the recombination device from deteriorating due to the wetting of components of the recombination device with condensation. For example, the recombination device can comprise a ceramic tube or element with an integrated precious metal capacitor, whereby these components are not mounted on a base of the recombination system, but directly beneath a cover of the recombination system.This eliminates the need for an additional shielding element for the condensate, which saves costs. In addition to the asymmetrical structure of the catalyst material, this type of suspension is generally thermally more favorable. The risk of increased heat generation during extreme recombination and extreme overheating, with the resulting destruction of the recombination system, can thus be counteracted. In other words, suspending the recombination device with, for example, a ceramic, porous tube or element with an integrated precious metal capacitor, creates more favorable thermal conditions, significantly reducing heating and allowing for better heat dissipation.

[0022] Further preferred embodiments of the invention emerge from the remaining features mentioned in the subclaims.

[0023] Furthermore, in a further preferred embodiment of the invention, the holder is arranged on a closure element of the recombination system, wherein the closure element comprises at least one guide element, such that a process medium, in particular water, is guided by means of the guide element to at least a partial region of an interior region of the recombination system. A further advantage of this type of suspension of the recombination device, which, for example, comprises the tube or element made of a ceramic material with an integrated precious metal capacitor, is that it is no longer possible for the condensed water to drip down from the upper region of the recombination system, for example from a closure element, for example in the form of a plug, and for the recombination device, for example a ceramic, to be closed.To support this effect, it can also be provided that, for example, parts of the recombination device in the form of a ceramic, porous tube with a precious metal condenser are additionally attached to the upper area. This can be done either on a dome of the recombination system or on an external plug designed for use in a recombination system. Both the dome and the plug can have a circular cone inside or other suitable shapes for draining the condensed water to improve the drainage of the condensate. The closure element can therefore also be provided as a single piece in a dome of the recombination system.

[0024] Furthermore, in a further preferred embodiment of the invention, the recombination device has at least one tapered region designed to connect to the holder on at least one side of the holder. Thus, the tapered region can be particularly well-designed for a secure and stable connection.

[0025] In a further preferred embodiment of the invention, it is also provided that the holder has at least one region which is designed to accommodate at least one flashback protection element, and wherein the holder comprises at least one fixing element which is designed to connect to the at least one tapered region of the recombination device. This enables particularly reliable operation of the recombination system. The fixing element can, for example, be a clip. In other words, the suspension of the recombination device, for example in the form of the ceramic tube with catalyst, can be implemented in a special embodiment using a mechanical clip system. The tapered region and the fixing element, or several of these components, represent this clip system, wherein the number and arrangement can be adapted to the respective case.The advantages include, for example, that no additional fixing elements are required and the fastening can be realized without adhesive, as the strength properties of adhesives could change due to moisture and heat. This is advantageous because there is no drying time or long-term release of foreign substances during processing. The fastening can therefore have tapered areas, which can also be referred to as corresponding formations. In addition, to support the strength of the fastening, the recombination device or the ceramic tube, and thus the catalyst, can have corresponding bores and / or notches. As already mentioned, the fastening can be integrated into the dome or screwed in as a separate part in the form of a plug.

[0026] Furthermore, in a further preferred embodiment of the invention, the holder comprises at least one labyrinth-like opening designed to functionally connect the at least one flashback protection element to the recombination device. In other words, in a particular embodiment, the holder, which can also be integrated with a closure element or plug, can have said labyrinth-like opening in the form of a meandering channel that delays gas outflow, thus allowing more time for the hydrogen / oxygen mixture to penetrate the recombination device, which can be, for example, a ceramic, porous tube with a precious metal capacitor.

[0027] Furthermore, in a further preferred embodiment of the invention, the first and second portions of the catalyst material are bonded together. The aforementioned advantages can thus be realized even more effectively.

[0028] Furthermore, in a further preferred embodiment of the invention, the recombination device comprises a ceramic tube, with the first and second subsets being arranged in the ceramic tube. The aforementioned advantages can thus be implemented even more effectively.

[0029] Finally, in a further preferred embodiment of the invention, a recombination device is provided for use in a recombination system according to claims 1 to 7.

[0030] The recombination device comprises an asymmetrically distributed catalyst material, wherein a first subset of the catalyst material is larger than a second subset and wherein an average distance from the first subset to a holder of the recombination device is larger than an average distance from the second subset to a holder of the recombination device.

[0031] Due to the asymmetrical use of the catalyst, which can be provided in a tube, for example, the temperature on the attached side of the recombination device, which can comprise a ceramic, for example, is significantly reduced. By increasing the distance to the attachment with an appropriately selected length of the recombination device, for example in the form of a ceramic tube, the recombination mass is aligned on one side away from the attachment base or holder, so that the thermal load on the attachment is significantly reduced. The catalyst, for example in the form of spheres or rod, is then arranged on one side and the temperature at the attachment drops. Corresponding tests with the same amount of catalyst and the various arrangements show a significant reduction in the thermal load on the holder or attachment.

[0032] Thus, the proposed device makes it possible to achieve lower overheating of the holder or mounting for the recombination device, for example, comprising a gas-permeable ceramic with an integrated precious metal catalyst, while maintaining the overall height of the recombination device, for example, comprising a ceramic tube, and maintaining a constant circumference of the catalyst material. Thus, the amount of catalyst remains identical to other arrangements, and only an asymmetrical arrangement of the catalyst in the recombination device, for example, comprising a gas-permeable ceramic, achieves this technical effect of improved thermal management.

[0033] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

[0034] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a recombination system with a recombination device; Fig. 2 a recombination system with a recombination device in a holder in the ceiling area; Fig. 3 Examples of arrangements of catalyst material in respective recombination devices according to the prior art; Fig. 4 Examples of arrangements of catalyst material in respective recombination devices according to the present invention.

[0035] Fig. 1 shows a sectional view of a recombination system 10 with a recombination device 20, as might be represented, for example, according to the prior art. The recombination system 10 comprises a dome 30 and a recombination device 20. The dome 30 is shown here, by way of example, as a substantially rectangular, hollow, and cylindrical geometry. The dome 30 has an outer wall 40 and an inner wall 50. Relative to the image plane, the dome 30 has rounded corner regions at the top, such that a ceiling region 60 transitions in an arc shape into lateral walls 70. Again relative to the image plane, the dome 30 has an opening region 80 at the bottom, into which the gases O2 and H2 flow. These gas flows are each schematically represented with different dashed lines, with arrows indicating that these gases flow from below into an interior of the dome 30. A bracket 90 can be seen above the opening area 80.The recombination device 20 is held upright in the holder 90, which can also be referred to as a fixation. Two jaw elements 100 of the holder 90 hold the recombination device 20 in an upright position.

[0036] The recombination device 20 has a substantially cylindrical geometry. All geometries, dimensions, and proportions shown are to be understood only as examples and are to be understood merely as a schematic arrangement.

[0037] The recombination device 20 is illustrated here as a gas-permeable ceramic with an integrated precious metal catalyst and can also be referred to as a ceramic tube. The different dashed lines of the two gases are shown in a circle inside the dome 30, with the arrowhead pointing toward the ceramic tube. Block arrows point away from the ceramic tube and visualize the resulting water vapor 110. The water vapor 110 condenses on the inner wall 50 to form condensed water 120. In this respect, the dome 30 is intended for the condensation of the water vapor 110. In the upper region of the dome 30, water vapor 110 also condenses in the ceiling area 60. According to the principle of gravity, it is possible for condensed water 120 to fall toward the recombination device 20 in the form of water droplets (not shown in detail). Accordingly, water spots (not shown in detail) can form on the recombination device 20.In other words, the ceramic is wetted with condensate 120, so that the efficiency of the recombination device 20 is reduced.

[0038] Fig. Figure 2 shows a recombination system 10 with a recombination device 20 in a holder 90 in the ceiling area 60. The holder is arranged on a closure element 130. For example, the holder 90 can be provided in one piece with the closure element 130, as shown schematically in Figure 1. Fig. 2. The closure element 130 comprises a guide element 140, which has a conical geometry, so that condensed water or condensate 120 can ultimately be guided to an inner wall 50 of a dome 30 of the recombination system 10. The dome 30 also has an outer wall 40 and, in the lower region, comprises an opening region 80, into which the gases O2 and H2 flow. These gas flows are schematically represented with different dashed lines, with arrows indicating that these gases flow from below into the interior of the dome 30. These gases then flow upwards and, coming from below, reach the recombination device 20. This is shown in the Fig. 2 indicated by dashed lines in the hollow dome 30.

[0039] The recombination device 20 is depicted as a gas-permeable ceramic with an integrated noble metal catalyst, with a catalyst material 150 arranged at the lower end of the gas-permeable ceramic or ceramic tube. The catalyst material 150 can be, for example, a noble metal catalyst. This catalyst material 150 is arranged inside the tube and is located largely below an imaginary center line of the recombination device 20.

[0040] In other words, the catalyst material 150 is located predominantly opposite the holder 90 and is thus provided asymmetrically distributed in the recombination device 20.

[0041] The recombination device 20 also has two tapered regions 160 in the upper area. At these locations, the holder also has two matching fixing elements 170. These fixing elements 170 are in the form of clips. Together, the tapered regions 160 and the fixing elements 170 form a type of clip system, so that the recombination device 20 is held in the upper area of ​​the system 10. The closure element 130 also has a region 180 designed to accommodate a flashback protection element 190. Below this region 180, an opening 200 can also be seen, which functionally connects the flashback protection element 190 in the region 180 to the recombination device 20. The flashback protection element 190 could, for example, represent a ceramic frit as flashback protection.

[0042] Fig. Figure 3 shows examples of arrangements of catalyst material 150 in respective recombination devices 20 according to the prior art. The respective recombination devices 20 have respective ceramic tubes 210, each of which has catalyst material 150 inside. The respective catalyst material 150 is held in the ceramic tube 210 by a closure (220) at the top and bottom. The respective catalyst material 150 is provided symmetrically within the respective ceramic tube 210.

[0043] Fig.Figure 4 shows examples of arrangements of catalyst material 150 in respective recombination devices 20 according to the present invention. The respective recombination devices 20 have respective ceramic tubes 210, each of which contains catalyst material 150 inside. The respective catalyst material 150 is held at the top and bottom in the ceramic tube 210 by a closure 220. Relative to the image plane, the respective recombination devices 20 are held at the bottom by a holder 90.

[0044] The first recombination device 20 on the left has a symmetrical distribution of the catalyst material 150. The remaining recombination devices 20 each have an asymmetrical distribution of the catalyst material 150, with a first subset 230 of the catalyst material 150 being larger than a second subset 240. The larger first subset 230 is also further away from the holder 90 than the second subset 240. The first and second subsets 230, 240 are each provided above and below a center line, indicated by dashed lines, of the respective recombination devices 20.

[0045] A special case is shown on the far right, since here the entire catalyst material 150 is provided above the dashed center line. In comparison to the symmetrical distribution of the catalyst material 150, the amount of catalyst material 150 to be distributed remains the same in all examples shown. Respective measuring points T1, T2, T3, T4 are shown on the holder 90, at each of which a temperature is measured during an operating state. The further the catalyst material 150 is removed from the holder 90, the lower the measured temperature at the measuring point of the holder 90, which can also be referred to as the attachment, so that the following relationship is established in the test during operation of the respective recombination devices 20: T4 < T3 < T2 < T1. Reference symbol 10 Recombination system 20 Recombination facility 30 Cathedral 40 exterior wall 50 inner wall 60 ceiling area 70 side wall / wall 80 opening range 90 bracket 100 jaw element 110 water vapor 120 Condensation 130 locking element 140 Guide element 150 catalyst material 160 tapering area 170 Fixing element 180 area 190 Backfire protection element 200 opening 210 ceramic tubes 220 closure 230 first subset 240 second subset

Claims

[1] A recombination system (10) comprising a recombination device (20) for the catalytic recombination of hydrogen and oxygen produced in accumulators to form water, wherein the recombination device (20) comprises at least one catalyst material (150) in at least one partial region, which catalyst material has a first partial amount (230) of the catalyst material (150) at least in a partial region above a center line of the recombination device (20) relative to a position of a holder (90) of the recombination system (10) for the recombination device (20), wherein the first partial amount (230) is larger than a second partial amount (240) of the catalyst material (150) which is located from the center line of the recombination device (20) in the direction of the holder (90), characterized by that the holder (90) is arranged in a ceiling area (60) of the recombination system (10). [2] Recombination system (10) according to claim 1, wherein the holder (90) is arranged on a closure element (130) of the recombination system (10), wherein the closure element (130) comprises at least one guide element (140) so that a process medium, in particular water, is guided by means of the guide element to at least a partial region of an interior region of the recombination system (10). [3] Recombination system (10) according to claim 1 and 2, wherein the recombination device (20) has at least one tapered region (160) which is designed to connect to the holder (90) on at least one side of the holder (90). [4] Recombination system (10) according to claim 3, wherein the holder (90) has at least one region (180) which is designed to receive at least one flashback protection element (190) and wherein the holder (90) comprises at least one fixing element (170) which is designed to connect to the at least one tapered region (160) of the recombination device (20). [5] Recombination system (10) according to claim 4, wherein the holder (90) comprises at least one labyrinth-like opening (200) which is designed to functionally connect the at least one flashback protection element (190) to the recombination device (20). [6] The recombination system (10) of claim 1, wherein the first and second portions (230, 240) of the catalyst material (150) are bonded together. [7] A recombination system (10) according to claim 1 or claim 6, wherein the recombination means (20) comprises a ceramic tube, wherein the first and second subsets (230, 240) are arranged in the ceramic tube (210). [8] Recombination device (20) for use in a recombination system (10) according to claims 1 to 7, characterized by in that the recombination device (20) comprises an asymmetrically distributed catalyst material (150), wherein a first subset (230) of the catalyst material (150) is larger than a second subset (240) and wherein an average distance from the first subset (230) to a holder (90) of the recombination device (20) is greater than an average distance from the second subset (240) to the holder (90) of the recombination device (20).

Images