CN1547007A

CN1547007A - Three-cell series compound-carbon monoxide transducer and manufacturing method thereof

Info

Publication number: CN1547007A
Application number: CNA2003101241651A
Authority: CN
Inventors: 林立克
Original assignee: YUEQING XIAISI ELECTRON CO Ltd
Current assignee: YUEQING XIAISI ELECTRON CO Ltd
Priority date: 2003-12-08
Filing date: 2003-12-08
Publication date: 2004-11-17

Abstract

The invention discloses a kind of three-battery connected in series compound-carbon oxide sensor and the manufacturing method. The sensor has a chemical battery, whose two ends are the electron conductive material layers, the middle has four mixed conductive layers namely the conductive layer 1, 2, 3, 4 and three ions conductive layers namely the ion conductive layer 1, 2, and 3. The four mixed conductive layers and the three ion conductive layers form the three independent batteries; the three batteries are connected in series. The sensor has a big output signal, sensitivity and precision, the restoration period is short, and it can be used to measure the gas for oxidizing and reducing reaction directly.

Description

Three-cell series-connection compound carbon monoxide sensor and manufacturing method thereof

Technical Field

The present invention relates to a carbon monoxide sensor and a method for manufacturing the same, and more particularly, to a battery-type electrochemical sensor and a method for manufacturing the same.

Background

Currently, several million carbon monoxide electrochemical sensors are produced annually by Kidy-software corporation of the united states as in united states patents 6200443B1,5650054 and 5573648 owned by Atwood corporation of the united states. The core principle of the U.S. patent is a fuel cell, which adopts a normal-temperature catalyst and has the following reactions:

——(1)

referring to fig. 1, the working principle is briefly described as follows;

electrons generated in the mixed conducting layer 1 run from the outer path to the mixed conducting layer 2, protons generated in the mixed conducting layer 1 pass through the ion conducting layer from the inside, and the reaction in the mixed conducting layer 2 is:

——(2)

the overall reaction formula is: ——(3)

the electrons cause a voltage drop E1 across the resistor R, E1 is proportional to the CO gas concentration in the photoconductive layer 1, and the CO gas concentration at the photoconductive layer 1 can be known by measuring E1.

In the sensor shown in fig. 1, when the reaction (1) is performed, a part of the carbon monoxide molecules passes through the ion conductive layer by diffusion and finally enters the mixed conducting layer 2, and the carbon monoxide molecules entering the mixed conducting layer 2 generate a reverse reaction:

——(4)

this reaction is identical to (3), but the polarity of the voltage drop produced at the resistor R, E2, is opposite to that of E1. A drop in the output signal is caused, reducing the sensitivity and accuracy of the sensor. The carbon monoxide gas molecules entering the mixing layer 2 also cause the sensor togenerate a negative signal when the outer carbon monoxide concentration drops to 0 (corresponding to the disappearance of E1). Namely:

e2+ E1 ═ E2 (minus) +0<0 — (5)

This negative signal E2 is zero until all carbon monoxide molecules in the conductive layer 2 are consumed by the reaction formula (4). The sensor shown in fig. 1 has a recovery process in which the output signal changes from a negative value to a zero value after the external carbon monoxide gas is zero. Typically in the range of minutes to hours. By combining the two points, the sensor shown in fig. 1 has small output signal, low sensitivity and accuracy and long recovery time, and limits the application range of the sensor.

Disclosure of Invention

The present invention has been made to overcome the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a three-cell series multiple carbon monoxide sensor and a method for manufacturing the same, which has a large output signal, high sensitivity and accuracy, a short recovery time, and can directly measure any gas that can undergo an oxidation-reduction reaction.

In order to achieve the purpose, the invention adopts the following solution: a compound carbon monoxide sensor with three batteries connected in series is provided with an electrochemical battery, wherein two ends of the electrochemical battery are provided with electronic conducting material layers, the middle of the electrochemical battery is provided with four mixed conducting layers, namely a first mixed conducting layer, a second mixed conducting layer, a third mixed conducting layer and a fourth mixed conducting layer, and three ion conducting layers, namely a first ion conducting layer, a second ion conducting layer and a third ion conducting layer, wherein the four mixed conducting layers and the three ion conducting layers form three independent batteries which are connected in series.

Each independent cell consists of two mixed conducting layers and one ion conducting layer.

The first battery and the second battery share the second mixed conducting layer, and the second battery and the third battery share the third mixed conducting layer.

The manufacturing method comprises the following steps: the first mixed conducting layer and the fourth mixed conducting layer are respectively manufactured on the two electronic conducting material layers in advance, the second mixed conducting layer and the third mixed conducting layer are manufactured on two sides of a proton conducting material in advance, the first mixed conducting layer, the second mixed conducting layer, the third mixed conducting layer and the fourth mixed conducting layer are made of mixed conducting materials with ion conducting performance and electron conducting performance simultaneously, the proton conducting material is used as the third ion conducting layer, then the two electronic conducting material layers and the proton conducting material are assembled at high temperature and high pressure through adhesives, the adhesives form two mutually independent continuous films, the adhesives form ion conducting capacity simultaneously in the process of forming the continuous films, and the two mutually independent continuous films form the first ion conducting layer and the third ion conducting layer.

The sensor can be used for directly measuring carbon monoxide, and any gas which can be subjected to oxidation-reduction reaction, such as hydrogen, ammonia and the like. The working principle is as follows:

assuming that each cell has an output in the form of equation (5)

E1+ E2═ output voltage signal

Then in the Atwood sensor, assuming 30% CO gas enters the mixed conducting layer two region, then E2 is 30% of E1, and if E1 is 1mv and E2 is 0.3mv at 100ppm CO concentration, the signal output of the Atwood sensor is 0.7 mv.

Similarly, when the external CO concentration is zero, the Atwood sensor has an output signal of-0.3 mv, which corresponds to a 43ppm CO concentration signal. At this point, the CO is measured again immediately, and the CO concentration would have to be 44ppm before the sensor would output a signal greater than 0.

The sensor 30% of the E2 signal is not generated by the first battery but by the second battery, but the E2 signal and the E1 signal are of the same polarity so the output signal does not decrease. Assuming that 30% of the gas in the second cell is not reacted and enters the third cell; again, similarly, if 30% of the gas is not reacted, and reacts in the third cell and enters the fourth mixed conducting layer, then the total output signal is:

E_{general assembly}＝E1+E2+E3+E4-(6)

Wherein E1-1 mv>0

E2＝0.3×0.7＝0.21mv＞0

E3＝0.3×0.3×0.7＝0.063mv＞0

E4＝0.3×0.3×0.3＝-0.027mv＜0

The total output voltage is:

E_{general assembly}＝1mv+0.21mv+0.063mv-0.027mv＝1.246mv

In other words, a 100ppm co gas concentration, for which the output reading is 1.246mv, is 1.8 times greater than the Atwood sensor (prior art) output signal by 1.246/0.7.

Likewise, when the external CO gas is 0, the output is minus 0.027mv, corresponding to 0.027mv/1.246mv × 100-2 ppm, i.e. if immediately followed again by continuous testing, the recovery time is zero, causing an error of 2ppm, corresponding to 44ppm of the Atwood sensor under the same conditions, which 2ppm is almost negligible.

Therefore, compared with the prior art, the utility model, have that output signal is big, sensitivity and precision are high, recovery time advantage such as short.

Drawings

FIG. 1 is a schematic representation of a prior art organizational structure.

Fig. 2 is a schematic view of the organization structure of the present embodiment.

Fig. 3 is a schematic diagram of a first cell structure in the three-cell series multiple carbon monoxide sensor shown in fig. 2.

Fig. 4 is a schematic diagram of a second cell structure in the three-cell series multiple carbon monoxide sensor shown in fig. 2.

Fig. 5 is a schematic diagram of a third cell structure in the three-cell series multiple carbon monoxide sensor shown in fig. 2.

In the figure: 1. the solar cell comprises conductive layers 1 and 2, mixed electronic conductive layers 1 and 3, an ion conductive layer 4, mixed electronic conductive layers 2 and 6, an electronic conductive material layer 7, mixed conductive layers I and 8, ion conductive layers I and 9, mixed conductive layers II and 10, ion conductive layers II and 11, mixed conductive layers III and 12, ion conductive layers III and 13 and mixed conductive layer IV.

Detailed Description

The present invention will be described with reference to the following embodiments and accompanying drawings.

Referring to fig. 1 to 5, a three-cell series multiple carbon monoxide sensor has an electrochemical cell with electronically conductive material layers 6, 14 at both ends, four mixed conductive layers, i.e., a first mixed conductive layer 7, a second mixed conductive layer 9, a third mixed conductive layer 11, a fourth mixed conductive layer 13, and three ionically conductive layers, i.e., a first ionically conductive layer 8, a second ionically conductive layer 10, and a third ionically conductive layer 12, in the middle, the four mixed conductive layers and the three ionically conductive layers form three independent cells, and the three independent cells are connected in series.

Referring to fig. 2 to 5, each individual cell is composed of two mixed conductive layers and one ion conductive layer, the first cell and the second cell share the second mixed conductive layer 9, and the second cell and the third cell share the third mixed conductive layer 11.

The manufacturing method of the three-battery series-connection compound carbon monoxide sensor comprises the following steps: the first mixed conducting layer 7 and the fourth mixed conducting layer 13 are respectively manufactured on the two electronic conducting material layers 6 and 14 in advance, the second mixed conducting layer 9 and the third mixed conducting layer 11 are manufactured on two sides of a proton conducting material in advance, the first mixed conducting layer 7, the second mixed conducting layer 9, the third mixed conducting layer 11 and the fourth mixed conducting layer 13 are made of mixed conducting materials with ion conducting performance and electron conducting performance simultaneously, the proton conducting material is used as the third ion conducting layer 10, then the two electronic conducting material layers 6 and 14 and the proton conducting material are assembled at high temperature and high pressure through adhesives, the adhesivesform two mutually independent continuous films, the adhesives form ion conducting performance simultaneously in the process of forming the continuous films, and the two mutually independent continuous films form the first ion conducting layer 8 and the third ion conducting layer 12.

Claims

1. A three-cell series multiple carbon monoxide sensor having an electrochemical cell, characterized by: the electrochemical cell is provided with electronic conducting material layers (6 and 14) at two ends, four mixed conducting layers, namely a first mixed conducting layer (7), a second mixed conducting layer (9), a third mixed conducting layer (11), a fourth mixed conducting layer (13) and three ion conducting layers, namely a first ion conducting layer (8), a second ion conducting layer (10) and a third ion conducting layer (12) in the middle, wherein the four mixed conducting layers and the three ion conducting layers form three independent cells which are connected in series.

2. A method of manufacturing a three-cell series multiple carbon monoxide sensor according to claim 1, wherein: the first mixed conducting layer (7) and the fourth mixed conducting layer (13) are respectively manufactured on the two electronic conducting material layers (6 and 14) in advance, the second mixed conducting layer (9) and the third mixed conducting layer (11) are manufactured on two sides of a proton conducting material in advance, the first mixed conducting layer (7), the second mixed conducting layer (9), the third mixed conducting layer (11) and the fourth mixed conducting layer (13) are all made of mixed conducting materials with ion conducting performance and electronic conducting performance, the proton conductive material is used as an ion conductive layer III (10), then two electronic conductive material layers (6, 14) and the proton conductive material are assembled at high temperature and high pressure by using an adhesive, the adhesive forms two independent continuous films, in the process of forming the continuous film, and simultaneously, ion conduction capability is formed, and two layers of independent and continuous films form an ion conduction layer I (8) and an ion conduction layer III (12).

3. A three-cell series multiple carbon monoxide sensor according to claim 1, wherein: each individual cell is composed of two mixed conducting layers and one ion conducting layer.

4. A three-cell series multiple carbon monoxide sensor according to claim 1, wherein: the first battery and the second battery share a second mixed conducting layer (9), and the second battery and the third battery share a third mixed conducting layer (11).