CN215953352U

CN215953352U - Miniature CO based on NDIR principle2Sensor with a sensor element

Info

Publication number: CN215953352U
Application number: CN202121796783.0U
Authority: CN
Inventors: 孙建海; 陈婷婷; 马天军; 张新晓; 赵佩月
Original assignee: Aerospace Information Research Institute of CAS
Current assignee: Aerospace Information Research Institute of CAS
Priority date: 2021-08-03
Filing date: 2021-08-03
Publication date: 2022-03-04
Anticipated expiration: 2031-08-03

Abstract

The utility model relates to a miniature CO based on NDIR principle₂Sensor belongs to infrared sensor technical field. The sensor comprises a sensor shell, a film-coated air chamber, a light source, an infrared detector, a circuit board and a shell base, wherein the circuit board is fixed on the shell base; air holes are distributed on the upper surfaces of the sensor shell and the film coating air chamber; the inner surface of the film-coated air chamber is plated with a metal reflecting film; the front part of the infrared detector is provided with a detection CO₂Using a filter. The sensor has the advantages of miniaturization, low power consumption, low cost, high precision, high reliability and long service lifeIs characterized by being used for CO₂High sensitivity and quick detection of gas.

Description

Miniature CO based on NDIR principle2Sensor with a sensor element

Technical Field

The utility model relates to aMini-CO based on NDIR principle₂Sensor belongs to infrared sensor technical field.

Background

The thermal runaway of the lithium ion battery is a form of battery failure caused by the rapid rise of the battery temperature due to the fact that the heat is far greater than the heat dissipation capacity in the use process of the battery, and generally, the high temperature causes the decomposition of a negative electrode SEI film, the decomposition of a positive electrode active material and the oxidative decomposition of electrolyte to generate a large amount of gas, so that the gas pressure in the lithium ion battery is rapidly increased, the battery is exploded, a large amount of high-temperature, combustible and toxic gas is released from the battery, and the personal and property safety of passengers can be seriously threatened. Research shows that the gas with the largest thermal runaway release amount is CO₂The gas fraction reached 35.56%. At present, the most common CO at home and abroad₂The detection method mainly comprises the following steps: infrared gas sensors, semiconductor gas sensors, electrochemical gas sensors, catalytic combustion gas sensors, thermal conductivity gas sensors, and the like. Compared with other methods, the infrared gas sensor utilizing the principle of the non-dispersive infrared method (NDIR) has the advantages of high precision and sensitivity, good selectivity, stability and reliability, high reaction speed, low possibility of poisoning, long service life, wide measuring range, high anti-interference capability and the like.

Currently, NDIR CO₂Most of the gas sensors have the following problems: (1) the sample cell and the absorption cell adopt a multi-reflection cell structure to increase the absorption optical path, the light path design is complex, the requirements on the mirror surface structure and the process are high, interference fringes, optical aberration and even memory effect (aiming at gas with strong adsorbability) are easily generated, and the measurement precision is reduced; (2) the front air chamber and the rear air chamber are mostly arranged in sequence along the light path, so that the measurement precision of the pyroelectric detector is easily interfered, and the measurement of low-concentration gas is difficult to realize stably; (3) the volume is large, the power consumption is high, and the method is difficult to be applied to the on-line monitoring technology which needs miniaturization and low power consumption, such as lithium ion thermal runaway and the like.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention is to provide a micro CO based on NDIR principle₂A sensor.

In order to achieve the purpose, the technical scheme of the utility model is as follows:

miniature CO based on NDIR principle₂The sensor comprises a sensor shell, a film-coated air chamber, a light source, an infrared detector, a circuit board and a shell base, wherein the circuit board is fixed on the shell base; air holes are distributed on the upper surfaces of the sensor shell and the film coating air chamber; the inner surface of the film-coated air chamber is plated with a metal reflecting film; the front part of the infrared detector is provided with a detection CO₂Using a filter.

Furthermore, a filtering membrane is arranged between the upper surface of the coating air chamber and the shell of the sensor. Can effectively remove water vapor and dust in the environment and prevent the coating air chamber, the light source and the infrared detector from being polluted.

Further, the metal reflecting film in the film coating air chamber is gold, silver or aluminum.

Further, the light source is an Infrared Radiation (IR) light source or a Light Emitting Diode (LED) lamp.

Further, the infrared detector is a pyroelectric detector or a thermopile.

Further, the light source and the infrared detector are respectively fixed on the circuit board through the base.

Advantageous effects

The utility model is based on NDIR principle and is a miniature CO₂The air chamber in the sensor adopts a diffuse reflection mode, so that the optical path is increased, the detection sensitivity is improved, and meanwhile, the metal reflection film is plated in the air chamber, so that the reflectivity is increased, and the light absorption is reduced. Has the characteristics of miniaturization, low power consumption, low cost, high precision, high reliability, long service life and the like, and can be used for CO₂High-sensitivity rapid detection of gas, especially CO in thermal runaway process of power battery₂And (4) detecting the gas.

Furthermore, a layer of filtering membrane is arranged in the sensor, so that water vapor in the environment can be removed, dust can be filtered, and the light source, the detector and the air chamber are prevented from being polluted.

Drawings

Fig. 1 is a schematic structural diagram of a sensor in embodiment 1 of the present invention.

Fig. 2 is an exploded view of the structure of a sensor in embodiment 1 of the present invention.

The device comprises a sensor shell, a filter membrane, a coating air chamber, an infrared light source, a detector, a base, a circuit board and a sensor shell base, wherein the sensor shell comprises 1 part, a filter membrane 2 part, a coating air chamber 3 part, the infrared light source 4 part, the detector 5 part, the base 6 part, the circuit board 7 part and the sensor shell base 8 part.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Miniature CO based on NDIR principle₂The sensor comprises a sensor shell 1, a film-coated air chamber 3, a light source 4, an infrared detector 5, a circuit board 7 and a shell base 8, wherein the circuit board 7 is fixed on the shell base 8, the light source 4 and the infrared detector 5 are respectively fixed on the circuit board 7, the film-coated air chamber 3 is sleeved outside the circuit board 7, and the sensor shell 1 is sleeved outside the film-coated air chamber 3; air holes are distributed on the upper surfaces of the sensor shell 1 and the film coating air chamber 3; the inner surface of the film coating air chamber 3 is plated with a metal reflecting film; a Micro Control Unit (MCU) is provided on the circuit board 7.

The working principle is as follows: the gas to be measured enters the coating air chamber 3 through the air holes on the upper surfaces of the sensor shell 1 and the coating air chamber 3, and the MCU generates a pulse signal with a certain frequency to control the infrared light source 4. The infrared light source 4 emits infrared light with continuous spectrum to irradiate the film coating air chamber 3 filled with the gas to be detected, the energy of the infrared light is weakened by the gas to be detected, for the gas to be detected with different concentrations, different absorption intensities can be generated at the same absorption peak position, and the absorption intensities are in direct proportion to the concentrations. The infrared light is reflected for many times on the inner wall of the coating air chamber 3 and is finally absorbed by the infrared detector 5, and the detector converts the absorbed light energy into an electric signal. After the infrared detector 5 collects the signals, the signals are processed by a two-stage amplifying and filtering circuit to obtain stable electric signals. After the signal is processed by the analog-to-digital conversion circuit, the sampled data is processed by the MCU control circuit and is sent to the upper computer through the serial port.

The selectivity of the gas can be achieved by a filter plate in front of the detector,different filters can be selected to transmit light with corresponding wavelengths. For the CO₂When detection is carried out, the detector 5 is provided with detection CO in front₂Using a filter.

And a filter membrane 2 is arranged between the upper surface of the coating air chamber 3 and the sensor shell 1. Can effectively remove water vapor and dust in the environment and prevent the coating air chamber 3, the light source 4 and the detector 5 from being polluted.

The metal reflecting film in the film coating air chamber 3 is gold, silver or aluminum. The film coating air chamber consists of an upper surface with holes, two side surfaces and a lower surface, and the inner surface of the film coating air chamber is plated with a layer of gold.

The light source 4 is an Infrared Radiation (IR) light source or a Light Emitting Diode (LED) lamp.

The detector 5 is a pyroelectric detector or a thermopile.

The light source 4 and the detector 5 are respectively fixed on a circuit board 7 through a base 6.

Example 1

As shown in FIGS. 1-2, a micro CO based on NDIR principle₂The sensor comprises a sensor shell 1, a film-coated air chamber 3, a light source 4, an infrared detector 5, a circuit board 7 and a shell base 8, wherein the circuit board 7 is fixed on the shell base 8, the light source 4 and the infrared detector 5 are respectively fixed on the circuit board 7, the film-coated air chamber 3 is sleeved outside the circuit board 7, and the sensor shell 1 is sleeved outside the film-coated air chamber 3; air holes are distributed on the upper surfaces of the sensor shell 1 and the film coating air chamber 3; the inner surface of the film coating air chamber 3 is plated with a metal reflecting film; the infrared detector 5 is provided with CO detection₂Using a filter.

And a filter membrane 2 is arranged between the upper surface of the coating air chamber 3 and the sensor shell 1. Can effectively remove water vapor and dust in the environment and prevent the coating air chamber 3, the light source 4 and the infrared detector 5 from being polluted.

The metal reflecting film in the film coating air chamber 3 is made of gold. The film coating air chamber consists of an upper surface with holes, two side surfaces and a lower surface.

The light source 4 is an LED lamp.

The infrared detector 5 is a pyroelectric detector.

The light source 4 and the infrared detector 5 are respectively fixed on a circuit board 7 through a base 6.

In summary, the present invention includes but is not limited to the above embodiments, and any equivalent substitutions or partial modifications made under the spirit and principle of the present invention should be considered within the protection scope of the present invention.

Claims

1. Miniature CO based on NDIR principle₂A sensor, characterized by: the sensor comprises a sensor shell (1), a film coating air chamber (3), a light source (4), an infrared detector (5), a circuit board (7) and a shell base (8), wherein the circuit board (7) is fixed on the shell base (8), the light source (4) and the infrared detector (5) are respectively fixed on the circuit board (7), the film coating air chamber (3) is sleeved outside the circuit board (7), and the sensor shell (1) is sleeved outside the film coating air chamber (3); air holes are distributed on the upper surfaces of the sensor shell (1) and the film coating air chamber (3); the inner surface of the film coating air chamber (3) is plated with a metal reflecting film; the front part of the infrared detector (5) is provided with CO for detection₂Using a filter.

2. The NDIR-principle-based micro CO according to claim 1₂A sensor, characterized by: and a filter membrane (2) is arranged between the upper surface of the coating air chamber (3) and the sensor shell (1).

3. The NDIR-principle-based micro CO according to claim 1₂A sensor, characterized by: the metal reflecting film in the film coating air chamber (3) is gold, silver or aluminum.

4. The NDIR-principle-based micro CO according to claim 1₂A sensor, characterized by: the light source (4) is an IR light source or an LED lamp.

5. The NDIR-principle-based micro CO according to claim 1₂A sensor, characterized by: the infrared detector (5) is a pyroelectric detector or a thermopile.

6. The NDIR-principle-based micro CO according to claim 1₂A sensor, characterized by: the light source (4) and the infrared detector (5) are respectively fixed on the circuit board (7) through the base (6).