Abstract
In an embodiment an electrochemical gas sensor includes a base plate comprising a base plate main surface, a catalytic layer configured to enhance chemical reactivity of gases, the catalytic layer is arranged on top of the base plate main surface and a solid electrolyte layer arranged on top of the catalytic layer, wherein the solid electrolyte layer comprises a ceramic material, and wherein the catalytic layer and the solid electrolyte layer are electrically contacted by contacts.
Claims
1. An electrochemical gas sensor comprising: a base plate comprising a base plate main surface; a catalytic layer configured to enhance chemical reactivity of gases, the catalytic layer is arranged on top of the base plate main surface; and a solid electrolyte layer arranged on top of the catalytic layer, wherein the solid electrolyte layer comprises a ceramic material, and wherein the catalytic layer and the solid electrolyte layer are electrically contacted by contacts.
2. The electrochemical gas sensor according to claim 1, further comprising a gas-sensitive layer arranged between the base plate main surface and the catalytic layer.
3. The electrochemical gas sensor according to claim 2, wherein the gas-sensitive layer comprises a thermistor ceramic or a metal oxide, and wherein the metal oxides comprises tin oxide, zinc oxide or copper oxide.
4. The electrochemical gas sensor according to claim 2, wherein the electrochemical gas sensor is configured to detect two or more different gases simultaneously.
5. The electrochemical gas sensor according to claim 1, further comprising an electrode layer arranged on top of the solid electrolyte layer.
6. The electrochemical gas sensor according to claim 1, wherein the ceramic material of the solid electrolyte layer is ion conductive and/or electrically conductive.
7. The electrochemical gas sensor according to claim 1, wherein the ceramic material of the solid electrolyte layer is a piezoelectric ceramic material.
8. The electrochemical gas sensor according to claim 1, wherein the catalytic layer comprises at least one metal or one metal oxide, and wherein the metal comprises platinum, palladium, silver, gold or copper.
9. The electrochemical gas sensor according to claim 1, wherein a gas-sensitive layer, the catalytic layer, a solid electrolyte layer and/or a electrode layer comprises a plurality of holes.
10. The electrochemical gas sensor according to claim 1, wherein the base plate comprises a heating device configured to enhance performance of the electrochemical gas sensor.
11. An electrochemical gas sensor array comprising: at least two electrochemical gas sensors according to claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In the following different embodiments of an electrochemical gas sensor are explained in more detail with the aid of drawings. Components of drawings which are similar to each other feature the same reference signs.
[0024] FIG. 1 illustrates a cross-sectional view of an electrochemical gas sensor;
[0025] FIG. 2 illustrates a cross-sectional view of another electrochemical gas sensor;
[0026] FIG. 3 illustrates a cross-sectional view of another electrochemical gas sensor;
[0027] FIG. 4 illustrates a cross-sectional view of another electrochemical gas sensor; and
[0028] FIG. 5 illustrates a top view of an electrochemical gas sensor.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0029] FIG. 1 illustrates, in a cross-sectional view, an electrochemical gas sensor comprising a base plate 1, a catalytic layer 2 and a solid electrolyte layer 3. The catalytic layer 2 is deposited on top of a base plate main surface 1a. The solid electrolyte layer 3 is deposited on top of the catalytic layer 2. The catalytic layer 2 and the solid electrolyte layer 3 are electrically contacted by contacts 4. The catalytic layer 2 comprises a metal selected from a group of metals comprising platinum, silver, gold and copper. The solid electrolyte layer 3 comprises a ceramic material which is ion conductive and/or electrically conductive. The ceramic material may also be a piezoelectric ceramic material. Both layers feature a plurality of holes which have been made by laser drilling (not depicted). The gas to be detected reaches the electrochemical gas sensor at the side opposite to the base plate 1. Due to the porosity of the solid electrolyte layer 3, the gas can easily come in contact with the catalytic layer 2. At the catalytic layer 2 the gas molecules of the gas to be detected are split in electrically charged species which are transported by the solid electrolyte layer 3 to the contacts 4. This creates an electrical current which is specific for the gas to be detected. Accordingly, the gas to be detected can be identified.
[0030] FIG. 2 illustrates, in a cross-sectional view, an electrochemical gas sensor similar to that shown in FIG. 1 wherein a gas-sensitive layer 5 is arranged between the base plate main surface 1a and the catalytic layer 2. Furthermore, an electrode layer 6 is deposited on top of the solid electrolyte layer 3. The introduction of the gas-sensitive layer 5 makes it possible to introduce another measurement principle into the electrochemical gas sensor. Accordingly, it is possible to detect at least two different gases simultaneously with the electrochemical gas sensor. Due to the electrode layer 6 it is possible to create a homogenous electrical field into the solid electrolyte layer 3, increasing the ability of the solid electrolyte layer 3 to transport the electrically charged species, which have been created at the catalytic layer 2, through the solid electrolyte layer 3 towards the contacts 4. This enhances the performance of the electrochemical gas sensor.
[0031] FIG. 3 illustrates, in a cross-sectional view, an electrochemical gas sensor which is similar to that shown in FIG. 2 wherein the base plate 1 comprises a heating device 7. The heating device 7 is incorporated in the base plate 1 in such a way that a membrane 1b is arranged on top of a substrate main surface 1d of a substrate 1e. The heating device 7 is arranged on top of the membrane 1b. Moreover, an insulating layer 1c is arranged on top of the heating device 7. The insulating layer 1c prevents an electrically conductive contact between the electrochemical gas sensor stack 2356 and the heating device 7. The heating device 7 delivers additional thermal energy to the electrochemical gas sensor stack 2356, enhancing the reactivity of the gases reaching the electrochemical gas sensor stack 2356. Accordingly, the performance of the whole electrochemical gas sensor can be enhanced.
[0032] FIG. 4 illustrates, in a cross-sectional view, an electrochemical gas sensor wherein the substrate 1e and the membrane 1b have been partially etched away.
[0033] FIG. 5 illustrates, in a top view, an electrochemical gas sensor which is similar to that shown in FIG. 4. It can be seen that a significant part of the base plate 1 is not present anymore. Only two bars of the membrane 1b, which are arranged like a cross, are left. The areas A indicate empty space. The electrochemical gas sensor stack 2356 is arranged in the center of the cross. This embodiment of the electrochemical gas sensor has the benefit that accessibility of the gas to be detected to the electrochemical gas sensor stack 2356 is improved. This enhances the performance of the whole gas sensor.
[0034] The electrochemical gas sensor is not limited to the embodiments given in the figures. In particular the arrangement of the single components of the electrochemical gas sensor may vary.
[0035] While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
