Electrochemical sensing element and device incorporating the same

Claim 2

An electrochemical device for determining the concentration of a component of a gaseous fluid, comprising: an electrochemical pumping cell including a first planar solid electrolyte body, and a first and a second electrode formed on said first solid electrolyte body, said first solid electrolyte body comprising an oxygen ion-conducting material; an electrochemical sensing cell including a second planar solid electrolyte body, and a third and a fourth electrode formed on said second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material; and a porous electric resistive ceramic layer comprising an electric resistive ceramic material sandwiched between said pumping cell and said sensing cell, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said pumping cell and said sensing cell throughout said lateral and transverse dimensions thereof, said pumping and sensing cells and said porous electric resistive ceramic layer being co-fired into a laminar structure.

Claim 3

The electrochemical device of claim 1, wherein one of said first and second electrodes, and one of said third and fourth electrodes are exposed to a cavity which is formed between said pumping and sensing cells.

Claim 4

The electrochemical device of claim 1, wherein said porous electric resistive ceramic layer comprises alumina or spinel as a major component thereof.

Claim 5

The electrochemical device of claim 1, wherein said porous electric resistive ceramic layer has a porosity of 5-30%.

Claim 6

An electrochemical device for determining the concentration of a component of a gaseous fluid, comprising: a first electrochemical cell including a first solid electrolyte body of a porous structure having a diffusion resistance to the gaseous fluid, said first solid electrolyte body comprising an oxygen ion-conducting material, a first electrode of a porous structure disposed on said first solid electrolyte body, and a second electrode electrically contacting said first solid electrolyte body, said first and second electrodes being spaced apart from each other; a second electrochemical cell including a second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material, a third electrode of a porous structure disposed on said second solid electrolyte body, and a fourth electrode disposed on said second solid electrolyte body and spaced apart from said third electrode; and a porous electric resistive ceramic layer comprising an electric resistive ceramic material and being interposed between said first and second electrochemical cells, and electrically insulating at least an assembly of said first solid electrolyte body or another solid electrolyte body adhering to said first solid electrolyte body from said second solid electrolyte body, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies, such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said first and second electrochemical cells directly, or indirectly through said another solid electrolyte body, throughout said lateral and transverse dimensions thereof, and said porous electric resistive ceramic layer cooperating with said first and second electrochemical cells to constitute a laminar structure; and said first electrode of said first electrochemical cell and said third electrode of said second electrochemical cell being exposed to substantially the same atmosphere.

Claim 7

An electrochemical device for determining the concentration of a component of a gaseous fluid, comprising: a first electrochemical cell including a first solid electrolyte body of a porous structure having a diffusion resistance to the gaseous fluid, said first solid electrolyte body comprising an oxygen ion-conducting material, a first electrode of a porous structure disposed on said first solid electrolyte body, and a second electrode electrically contacting said first solid electrolyte body, said first and second electrodes being spaced apart from each other; a second electrochemical cell including a second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material, a third electrode of a porous structure disposed on said second solid electrolyte body, and a fourth electrode disposed on said second solid electrolyte body and spaced apart from said third electrode; and a porous electric resistive ceramic layer comprising an electric resistive ceramic material and being interposed between said first and second electrochemical cells, and electrically insulating at least an assembly of said first solid electrolyte body or another solid electrolyte body adhering to said first solid electrolyte body from said second solid electrolyte body, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies, such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said first and second electrochemical cells directly, or indirectly through said another solid electrolyte body, throughout said lateral and transverse dimensions thereof, and said porous electric resistive ceramic layer cooperating with said first and second electrochemical cells to constitute a laminar structure; and said first electrode of said first electrochemical cell and said third electrode of said second electrochemical cell being exposed to substantially the same atmosphere.

Claim 8

The electrochemical device of claim 5, wherein said second electrode directly contacts said first solid electrolyte body.

Claim 9

The electrochemical device of claim 5, wherein said second electrode contacts said another solid electrolyte body adhering to said first solid electrolyte body.

Claim 10

The electrochemical device of claim 5, wherein said first and third electrodes are disposed in alignment with each other on opposite sides of said porous electric resistive ceramic layer.

Claim 11

The electrochemical device of claim 5, wherein said first and third electrodes are common.

Claim 12

The electrochemical device of claim 5, wherein one of said second electrode and said fourth electrodes is protected by gastight ceramic layer against exposure to said gaseous fluid, but exposed to a reference gas.

Claim 13

The electrochemical device of claim 10, wherein said gastight ceramic layers define a reference gas passage communicating with the ambient atmosphere, said one of the second and fourth electrodes being located adjacent to said reference gas passage for exposure to said ambient atmosphere.

Claim 14

The electrochemical device of claim 5, further comprising a gas-inlet layer of gastight ceramic material disposed over said first solid electrolyte body of porous structure and having a hole which is aligned with said first electrode, said hole being formed through the thickness of said gas-inlet layer, said gaseous fluid being introduced through said hole and directed to said first electrode perpendicularly to the surface of said first electrode.

Claim 15

The electrochemical device of claim 5, wherein said first solid electrolyte body consists of a plurality of solid electrolyte layers, wherein one of said solid electrolyte layers which contacts said first electrode has a porosity which is greater than the porosity in the other solid electrolyte layers.

Claim 16

The electrochemical device of claim 5, wherein said porous electric resistive ceramic layer has a porosity of 5-30%.

Claim 17

An electrochemical device for determining the concentration of a component of a gas, comprising: a first electrochemical cell including a first solid electrolyte body of a porous structure having a diffusion resistance to the gaseous fluid, said first solid electrolyte body comprising an oxygen ion-conducting material, and a first and a second electrode of a porous structure disposed in alignment with each other on opposite surfaces of said first solid electrolyte body; a second electrochemical cell including a second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material, a third electrode of a porous structure disposed on said second solid electrolyte body, and a fourth electrode spaced apart from said third electrode; a porous electric resistive ceramic layer comprising an electric resistive ceramic material and being interposed between said first and second electrochemical cells, and electrically insulating at least an assembly of said first solid electrolyte body or another solid electrolyte body adhering to said first solid electrolyte body from said second solid electrolyte body, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies, such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said first and second electrochemical cells directly, or indirectly through said another solid electrolyte body, throughout said lateral and transverse dimensions thereof, and said porous electric resistive ceramic layer cooperating with said first and second electrochemical cells to constitute a laminar structure; said first electrode of said first electrochemical cell and said third electrode of said second electrochemical cell being exposed to substantially the same atmosphere; means for applying an electric current between said first and second electrodes of said first electrochemical cell to control said atmosphere in the vicinity of said first electrode; and means for detecting said atmosphere as a electromotive force which is generated between said third and fourth electrodes.

Claim 18

An electrochemical device for determining the concentration of a component of a gas, comprising: a first electrochemical cell including a first solid electrolyte body of a porous structure having a diffusion resistance to the gaseous fluid, said first solid electrolyte body comprising an oxygen ion-conducting material, and a first and a second electrode of a porous structure disposed in alignment with each other on opposite surfaces of said first solid electrolyte body; a second electrochemical cell including a second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material, a third electrode of a porous structure disposed on said second solid electrolyte body, and a fourth electrode spaced apart from said third electrode; a porous electric resistive ceramic layer comprising an electric resistive ceramic material and being interposed between said first and second electrochemical cells, and electrically insulating at least an assembly of said first solid electrolyte body or another solid electrolyte body adhering to said first solid electrolyte body from said second solid electrolyte body, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies, such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said first and second electrochemical cells directly, or indirectly through said another solid electrolyte body, throughout said lateral and transverse dimensions thereof, and said porous electric resistive ceramic layer cooperating with said first and second electrochemical cells to constitute a laminar structure; said first electrode of said first electrochemical cell and said third electrode of said second electrochemical cell being exposed to substantially the same atmosphere; means for applying an electric current between said first and second electrodes of said first electrochemical cell to control said atmosphere in the vicinity of said first electrode; and means for detecting said atmosphere as a electromotive force which is generated between said third and fourth electrodes.

Claim 19

The electrochemical device of claim 15, wherein said first and third electrodes are disposed in alignment with each other on opposite sides of said porous electric resistive ceramic layer.

Claim 20

The electrochemical device of claim 15, wherein said first and third electrodes are common.

Claim 21

The electrochemical device of claim 15, wherein said fourth electrodes is protected by gastight ceramic layers against exposure to said gas, but exposed to a reference gas.

Claim 22

The electrochemical device of claim 18, wherein said gastight ceramic layers define a reference gas passage communicating with the ambient atmosphere, said fourth electrodes being located adjacent to said reference gas passage for exposure to said ambient atmosphere.

Claim 23

The electrochemical device of claim 15, wherein said porous electric resistive ceramic layer has a porosity of 5-30%.

Claim 24

An electrochemical device for determining the concentration of a component of a gas, comprising: a first electrochemical cell including a first solid electrolyte body of a porous structure having a diffusion resistance to the gaseous fluid, said first solid electrolyte body comprising an oxygen ion-conducting material, a first electrode of a porous structure disposed on said first planar solid electrolyte body, and a second electrode electrically contacting said first solid electrolyte body, said first and second electrodes being spaced apart from each other; a second electrochemical cell having a second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material, a third and a fourth electrode of a porous structure disposed in alignment with each other on opposite surfaces of said second electrolyte body; a porous electric resistive ceramic layer comprising an electric resistive ceramic material and being interposed between said first and second electrochemical cells, and electrically insulating at least an assembly of said first solid electrolyte body or another solid electrolyte body adhering to said first solid electrolyte body from said second solid electrolyte body, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies, such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said first and second electrochemical cells directly, or indirectly through said another solid electrolyte body, throughout said lateral and transverse dimensions thereof, and said porous electric resistive ceramic layer cooperating with said first and second electrochemical cells to constitute a laminar structure; said first electrode of said first electrochemical cell and said third electrode of said second electrochemical cell being exposed to substantially the same atmosphere; means for applying an electric current between said third and fourth electrodes of said second electrochemical cell to control said atmosphere in the vicinity of said third electrode; and means for detecting said atmosphere as an electromotive force which is generated between said first and second electrodes.

Claim 25

An electrochemical device for determining the concentration of a component of a gas, comprising: a first electrochemical cell including a first solid electrolyte body of a porous structure having a diffusion resistance to the gaseous fluid, said first solid electrolyte body comprising an oxygen ion-conducting material, a first electrode of a porous structure disposed on said first planar solid electrolyte body, and a second electrode electrically contacting said first solid electrolyte body, said first and second electrodes being spaced apart from each other; a second electrochemical cell having a second solid electrolyte body, said second solid electrolyte body comprising an oxygen ion-conducting material, a third and a fourth electrode of a porous structure disposed in alignment with each other on opposite surfaces of said second electrolyte body; a porous electric resistive ceramic layer comprising an electric resistive ceramic material and being interposed between said first and second electrochemical cells, and electrically insulating at least an assembly of said first solid electrolyte body or another solid electrolyte body adhering to said first solid electrolyte body from said second solid electrolyte body, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies, such that said porous electric resistive ceramic layer contacts both said first and second planar solid electrolyte bodies of said first and second electrochemical cells directly, or indirectly through said another solid electrolyte body, throughout said lateral and transverse dimensions thereof, and said porous electric resistive ceramic layer cooperating with said first and second electrochemical cells to constitute a laminar structure; said first electrode of said first electrochemical cell and said third electrode of said second electrochemical cell being exposed to substantially the same atmosphere; means for applying an electric current between said third and fourth electrodes of said second electrochemical cell to control said atmosphere in the vicinity of said third electrode; and means for detecting said atmosphere as an electromotive force which is generated between said first and second electrodes.

Claim 26

The electrochemical device of claim 21, wherein said first and third electrodes are disposed in alignment with each other on opposite sides of said porous electric resistive ceramic layer.

Claim 27

The electrochemical device of claim 21, wherein said first and third electrodes are common.

Claim 28

The electrochemical device of claim 21, wherein one of said second electrode and said fourth electrodes is protected by gastight ceramic layers against exposure to said gas, but exposed to a reference gas.

Claim 29

The electrochemical device of claim 24, wherein said gastight ceramic layers define a reference gas passage communicating with the ambient atmosphere, said second electrode being located adjacent to said reference gas passage for exposure to said ambient atmosphere.

Claim 30

The electrochemical device of claim 21, wherein said porous electric resistive ceramic layer has a porosity of 5-30%.

Claim 31

An electrochemical device for determining the concentration of a component of a gaseous fluid, comprising: an electrochemical pumping cell including a first planar solid electrolyte body, said first planar solid electrolyte body comprising an oxygen ion-conducting material, and a first and a second electrode formed on said first solid electrolyte body; an electrochemical sensing cell including a second planar solid electrolyte body, said second planar solid electrolyte body comprising an oxygen ion-conducting material and a third and a fourth electrode formed on said second solid electrolyte body another solid electrolyte body contacting one of said first and second planar solid electrolyte bodies, said solid electrolyte body comprising an oxygen ion-conducting material; and a porous electric resistive ceramic layer comprising an electric resistive ceramic layer and being sandwiched between said pumping cell and said sensing cell, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies such that said porous electric resistive ceramic layer contacts said one of the first and second planar solid electrolyte bodies of said pumping cell and said sensing cell indirectly through said another solid electrolyte body, and directly contacts the other of said first and second planar solid electrolyte bodies throughout said lateral and transverse dimensions thereof, said pumping and sensing cells and said porous electric resistive ceramic layer being co-fired into a laminar structure.

Claim 32

An electrochemical device for determining the concentration of a component of a gaseous fluid, comprising: an electrochemical pumping cell including a first planar solid electrolyte body, said first planar solid electrolyte body comprising an oxygen ion-conducting material, and a first and a second electrode formed on said first solid electrolyte body; an electrochemical sensing cell including a second planar solid electrolyte body, said second planar solid electrolyte body comprising an oxygen ion-conducting material and a third and a fourth electrode formed on said second solid electrolyte body another solid electrolyte body contacting one of said first and second planar solid electrolyte bodies, said solid electrolyte body comprising an oxygen ion-conducting material; and a porous electric resistive ceramic layer comprising an electric resistive ceramic layer and being sandwiched between said pumping cell and said sensing cell, said porous electric resistive ceramic layer having a thickness of not greater than 300 microns and having a porosity which is sufficient to mitigate thermal stresses between the porous electric resistive ceramic layer and each of the solid electrolyte bodies and having substantially the same lateral and transverse dimensions to said first and second planar solid electrolyte bodies such that said porous electric resistive ceramic layer contacts said one of the first and second planar solid electrolyte bodies of said pumping cell and said sensing cell indirectly through said another solid electrolyte body, and directly contacts the other of said first and second planar solid electrolyte bodies throughout said lateral and transverse dimensions thereof, said pumping and sensing cells and said porous electric resistive ceramic layer being co-fired into a laminar structure.