A smoke detector horizontal labyrinth for a battery pack

Abstract

The application provides a smoke detector horizontal labyrinth for a battery pack, adopts a horizontal structure, is light and thin in volume, is convenient to install in the battery pack, adopts a double-emission single-reception forward scattering combined with rear scattering optical structure, improves the accuracy of black smoke detection, and prevents missed reports, and comprises a PCB circuit board, characterized in that: a receiving tube, a first light-emitting tube and a second light-emitting tube are installed on the PCB circuit board, the receiving tube, the first light-emitting tube and the second light-emitting tube are arranged in parallel with the PCB circuit board, and the main optical axes of the three are also parallel with the PCB circuit board; the receiving tube and the first light-emitting tube form a forward scattering structure, and the receiving tube and the second light-emitting tube form a rear scattering structure; the first light-emitting tube is selected from an infrared light-emitting tube, and the second light-emitting tube is selected from a blue light-emitting tube, a green light-emitting tube, a yellow light-emitting tube, a red light-emitting tube or an infrared light-emitting tube.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smoke detectors, and particularly relates to a horizontal labyrinth for a smoke detector of a battery pack. BACKGROUND

[0002] With the vigorous promotion and popularization of new energy, modular battery packs are widely used in energy storage devices and electric vehicles. The frequent occurrence of battery self-ignition and explosion events has brought the safety problem of batteries to the agenda. The common practice in the industry is to use a battery management system (BMS) to monitor, but there are still many accidents, the main reason is that the causes and conditions of lithium battery thermal runaway are very complex, and the method of monitoring battery voltage, current and temperature cannot meet the monitoring requirements of battery thermal runaway. Typical battery thermal runaway has several steps and characteristics: gas evolution, electrolyte evaporation, smoke generation, fire and smoke, and possible explosion. The type and concentration of evolved gas are related to the battery type, battery capacity and various environmental factors, but the electrolyte evaporation and smoke generation are relatively constant and can be accurately detected by a smoke detector. Therefore, detecting non-gas particles is very helpful for early warning, and once the warning occurs, the host control platform can take measures to reduce the risk of further loss of control, such as cutting off the power supply, cooling, or even starting the fire fighting system.

[0003] In view of the monitoring problem of battery thermal runaway, a smoke detector as a conventional fire detection means can detect the change of battery state at the electrolyte evaporation stage and the smoke stage, so as to send information to the battery control system or the vehicle computer system, effectively detect the battery thermal runaway state, and take preventive measures in advance. The existing photoelectric smoke detector technology for fire fighting has the following difficulties in solving the problem of lithium battery thermal runaway fire:

[0004] 1) The existing smoke detector is relatively large in size, and the space in the battery pack is relatively small, so the existing smoke detector cannot be directly installed in the battery pack;

[0005] 2) The traditional single-infrared single-transmitting single-receiving forward scattering design is simple and easy to use, but the biggest problem is the identification of water vapor and black smoke, because water vapor and black smoke will absorb a large amount of infrared light, resulting in false negatives. During normal use or thermal runaway process in the battery pack, there will be water vapor or electrolyte evaporation, which will cause problems if not properly monitored. In addition, black smoke will be generated if the battery packaging material is on fire or smoldering, which will also cause problems if not properly monitored;

[0006] 3) The traditional single-shot single-receiver scheme will reduce the sensitivity to thin smoke due to the long optical path and insufficient detection sensitivity of the circuit, while the electrolyte volatilization and smoke generated in the early stage of battery thermal runaway are small, and if the problem can be detected as early as possible, it will be very helpful to avoid thermal runaway accidents, which is a big challenge to the traditional scheme;

[0007] 4) The working temperature range of the smoke detector for indoor fire-fighting is generally-10℃~+55℃, while the temperature range for lithium battery pack is at least-40℃~+85℃, or even higher, which requires higher stability and reliability of the optical device.

[0008] Therefore, designing a smoke detector for monitoring the thermal runaway problem of lithium battery in the battery pack needs to consider and innovate in the light of the above problems. SUMMARY

[0009] In order to solve the problems mentioned in the above content, the application provides a smoke detector horizontal labyrinth for battery pack, which adopts a horizontal structure, is light and thin in volume, and is convenient to install in the battery pack. The optical structure combining forward scattering and backward scattering of double-shot single-receiver improves the accuracy of black smoke detection and prevents false negatives.

[0010] The technical scheme is as follows:

[0011] A smoke detector horizontal labyrinth for battery pack, comprising a PCB circuit board, characterized in that: the PCB circuit board is provided with a receiving tube, a first light-emitting tube and a second light-emitting tube, the receiving tube, the first light-emitting tube and the second light-emitting tube are arranged parallel to the PCB circuit board, and the main optical axes of the three are also parallel to the PCB circuit board; the receiving tube and the first light-emitting tube constitute a forward scattering structure, and the receiving tube and the second light-emitting tube constitute a backward scattering structure; the first light-emitting tube is selected from red light or infrared light emitting tube, and the second light-emitting tube is selected from blue light or green light or yellow light or red light or infrared light emitting tube.

[0012] Further, a reflecting plate is arranged on the light path of the backward scattering structure, the reflecting plate is used for reflecting the light emitted by the second light-emitting tube into the receiving tube, and the second light-emitting tube is selected from blue light or green light or yellow light or red light or infrared light emitting tube. The reflecting plate provides a forced reflection surface, which provides a constant smoke-free background signal for the backward scattering path, which can be self-calibrated and used to assist in the judgment of black smoke, water vapor and thin gas.

[0013] Further, the horizontal labyrinth is characterized in that the main optical axis of the optical device, whether surface-mounted or pin-mounted, is parallel to the PCB circuit board, so that the height of the labyrinth depends on the height of the horizontally mounted optical device, and the height of the labyrinth can be controlled within 15 mm by selecting appropriate devices, and the typical value is 9 mm to 12 mm.

[0014] Further, the second light-emitting tube is located between the receiving tube and the first light-emitting tube, and the three are located in a semicircle of 180°; the first light-emitting tube and the receiving tube form forward scattering, and the included angle α between the main axes of the light paths is 120° to 160°; the second light-emitting tube and the receiving tube form backward scattering, and the included angle β between the main axes of the light paths is 20° to 60°.

[0015] Further, the receiving tube, the first light-emitting tube and the second light-emitting tube are provided with light path limiting mechanisms on both sides. These light path limiting mechanisms ensure that there is no obstruction on the light path of the first light-emitting tube, and ensure that there is no scattered light signal in the receiving tube when there is no smoke; the reflecting plate on the light path of the second light-emitting tube is not on the light path formed by the first light-emitting tube and its light path limiting mechanism, and does not affect the forward scattering optical path of the first light-emitting tube.

[0016] Further, the PCB circuit board is installed horizontally on the inner wall of the installation plane of the smoke detector or vertically on the inner wall of the installation plane of the smoke detector. Regardless of the installation method, the optical emission direction of the first light-emitting tube and the second light-emitting tube is preferably directed towards the center of the earth, which is beneficial for the dust or condensation in the labyrinth to be discharged from the labyrinth under the action of gravity.

[0017] Further, the second light-emitting tube is not installed, so that the labyrinth becomes the most classic single-transmitting and single-receiving mode, and is a front-line scattering mode, and the position of the second light-emitting tube and its optical limiting mechanism can be used as an additional smoke passage.

[0018] Further, the intersection of the optical axes of the receiving tube, the first light-emitting tube and the second light-emitting tube is a detection area. Therefore, the smoke passage of the smoke detector has two: one is the detection area and the area below it, and the other is the through smoke passage of the smoke detector that passes through the detection area and is perpendicular to the PCB circuit board, so that smoke can enter the detection area of the smoke detector from multiple directions.

[0019] Further, a partition is horizontally arranged in the middle of the smoke detector housing, the PCB circuit board is arranged above the partition, and the air inlet and gas collection space are arranged below the partition. The partition isolates the water vapor and condensation in the air inlet and smoke inlet space from the upper area, effectively protecting the PCB circuit board from water vapor interference.

[0020] The beneficial effects of the present application are:

[0021] 1、The receiving tube, the first light-emitting tube and the second light-emitting tube are parallel to the PCB circuit board, and the main optical axes of the three are also parallel to the PCB circuit board, so that a thin horizontal labyrinth structure design is realized, the height of the smoke detector depends on the height of the devices on the PCB circuit board, and then the smoke detector can be thin in at least one dimension, thereby meeting the demand of the narrow space inside the battery pack.

[0022] 2、The receiving tube and the first light-emitting tube form a forward scattering structure, and the receiving tube and the second light-emitting tube form a backward scattering structure, so that a double-emission-single-reception forward-backward scattering combined optical structure is formed, the accuracy of black smoke detection is improved, and false negatives are prevented.

[0023] 3、The reflection plate is arranged on the light path of the backward scattering structure, the reflection plate reflects the light emitted by the second light-emitting tube into the receiving tube, so that the backward scattering has a constant background signal when there is no smoke, if thick black smoke and water vapor appear at this time, the background signal decreases by an amount greater than the backward scattering signal of the smoke, so that the total received signal becomes smaller, if it is thin smoke at this time, the decrease of the background signal may be comparable to the increase of the backward scattering signal of the smoke, so that the total received signal does not change or slightly decreases, but the noise of the signal at this time is higher than that when there is no smoke, because the noise of the background signal when there is no smoke only depends on the noise of the circuit itself, and when smoke enters, the fluctuation of the signal becomes larger, which is reflected in the increase of the root mean square noise, so that the thin smoke can be judged by this simple method.

[0024] 4、The second light-emitting tube is located between the receiving tube and the first light-emitting tube, and the three are located in a semicircle of 180°, so that the area and volume are reduced, the volume of the smoke detector is further reduced, and the demand of the narrow space inside the battery pack is met.

[0025] 5、The second light-emitting tube and its light path limiting mechanism can be used as an additional smoke passage by not installing the second light-emitting tube.

[0026] 6、The PCB circuit board is parallelly installed on the inner wall of the installation plane of the smoke detector or vertically installed on the inner wall of the installation plane of the smoke detector, no matter which installation method is used, the optical emission direction of the first light-emitting tube and the second light-emitting tube is preferentially directed towards the center of the earth, which is beneficial to the discharge of dust or condensation in the labyrinth under the action of gravity.

[0027] 7、A partition is horizontally arranged in the middle of the smoke detector shell, the PCB circuit board is arranged above the partition, and the air inlet and gas collection space are arranged below the partition. The partition isolates the water vapor and condensation in the air inlet and smoke inlet space from the upper area, effectively protecting the PCB circuit board from water vapor interference. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the first type of horizontal maze and its optical layout according to the present invention;

[0029] Figure 2 This is a schematic diagram of the second type of horizontal maze and its optical layout according to the present invention;

[0030] Figure 3 This is a schematic diagram of the installation of the PCB circuit board of the present invention;

[0031] Figure 4 for Figure 3 A side view diagram. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments.

[0033] The following embodiments are used to illustrate the present invention, but should not be used to limit the scope of protection of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.

[0034] Traditional standard photoelectric smoke detectors typically require a maze component. This maze usually serves three purposes: first, to prevent external ambient light from interfering with the photoelectric device, especially the receiver; second, to provide a constant optical cavity to eliminate internal light reflection or confine it within a certain range; and third, to allow smoke to enter and exit the maze and converge on the smoke-sensitive area. The maze is usually the core component of a smoke detector, and its design significantly determines the detector's performance, making it a key research area for smoke detector manufacturers. Standard photoelectric smoke detectors also include an insect net component, which, as the name suggests, is a mesh-like component to prevent insects from entering the maze. This may be integrated with the maze or designed as a separate component. However, the space within the battery pack is a closed or semi-closed space, a relatively "clean" environment without ambient light interference or insect entry. Even if interference from ambient light or insects occurs, it can be avoided through the mechanical structure of the outer packaging, thus simplifying the maze design. Furthermore, the internal space of the battery is relatively small, and smoke quickly fills the entire space once generated, so there is no need for special treatment regarding smoke guidance and accumulation as required by traditional smoke detector mazes. However, this does not mean that the design of a smoke detector maze for battery thermal runaway protection is simpler, because its detection performance needs to be guaranteed within a limited size.

[0035] The size of the smoke detector depends on the specification of the battery pack cell, and the smoke detector can be installed parallel to the battery cell or vertically, but no matter how it is installed, it needs to have one dimension as small as possible to reduce the overall volume. The national standard GB / T 34013-2017 specifies the specifications and sizes of various power storage batteries for electric vehicles. The diameter of each type of cylindrical battery is between 18mm and 32mm, and the height is between 65mm and 134mm; the three-dimensional size 1 of each type of square battery is between 12mm and 86mm, the size 2 is between 65mm and 217mm, and the size 3 is between 80mm and 396mm; the three-dimensional size 1 of each type of soft pack battery is not marked, which can be seen as relatively thin, the size 2 is between 100mm and 228mm, and the size 3 is between 85mm and 342mm. Tesla uses traditional 18650, newer 21700 and latest 4680 cells, all of which are cylindrical cells, and the size of the 21700 cell is 21mm in diameter and 70mm in height, and the others are the same. The latest blade battery of BYD, i.e. long cell scheme, increases the length of the cell to the size of the battery pack, and the cell is very thin and can be inserted into the battery pack to improve the energy density and the heat dissipation level of the battery pack. Considering the series and parallel connection of the cells, the battery management circuit of the battery pack, the protection shell mechanism of the battery pack and other factors, the size of the smoke detector used in the battery pack also needs to be as small as possible, at least in one dimension, to facilitate installation. Therefore, if the size of the smoke detector can be reduced, especially in one direction, it will help to reduce the volume utilization rate of the battery pack and improve the energy density, and also help the mechanism assembly. Combined with the size of the battery cell and the size of the related non-smoke detector, the size of the overall smoke detector module in at least one direction of the 3D structure needs to be as small as possible, and considering the mechanical assembly and the thickness of the parts, the overall control is within 20mm (typical value 15-18mm), and the net height of the labyrinth device is controlled within 15mm (typical value 9-12mm).

[0036] The application provides a horizontal labyrinth smoke detector for a battery pack, which comprises a PCB circuit board, a receiving tube, a first light-emitting tube and a second light-emitting tube are mounted on the PCB circuit board, the receiving tube, the first light-emitting tube and the second light-emitting tube are arranged in parallel with the PCB circuit board, and the main optical axes of the three are also parallel to the PCB circuit board. The above-mentioned thin horizontal labyrinth structure design makes the height of the smoke detector depend on the height of the device on the PCB circuit board, so that the smoke detector can be thin in at least one dimension, thereby meeting the demand of the narrow space inside the battery pack.

[0037] The receiving tube and the first light-emitting tube form a forward scattering structure, and the receiving tube and the second light-emitting tube form a backward scattering structure, thereby forming an optical structure that combines forward and backward scattering with dual emission and single reception, which improves the accuracy of black smoke detection and prevents missed detection.

[0038] like Figure 1 In one embodiment shown: the pins 101 of the first LED 11, the pins 102 of the second LED 12, and the pins 201 of the receiver 2 are mounted on the PCB circuit board 4. The pins are shown in the schematic diagram. Surface mount devices are preferred for ease of installation; if not, small-pin devices are preferred. The device pins are bent before being mounted on the PCB circuit board 4. The PCB circuit board 4 is generally mounted on two sides. Optical devices are mounted separately on one side shown, and non-optical devices are mounted on the other side. Connectors (not shown) are also mounted on the other side. Figure 1 (Drawn in the middle) It can be installed on either side, depending on the mechanical height. The screw holes 6 of the PCB circuit board 4 are used to fix the PCB circuit board 4 to the corresponding mechanical component. The main optical axis of the first light-emitting diode 11 is denoted as a, the main optical axis of the second light-emitting diode 12 is denoted as c, and the main optical axis of the receiver 2 is denoted as b. The angle formed by the main optical axis a of the first light-emitting diode 11 and the main optical axis b of the receiver 2 is denoted as α, and the angle formed by the main optical axis c of the second light-emitting diode 12 and the main optical axis b of the receiver 2 is denoted as β. In optical design, it is preferred that the three main optical axes intersect at a point, and a spherical detection area 5 is formed with this point as the center. That is, the scattering of smoke in this area will be detected. The area on the PCB circuit board 4 that coincides with the detection area 5 needs to be cut out. The first light-emitting diode 11 is preferably a long wavelength such as infrared or red light, and the second light-emitting diode 12 is preferably a short wavelength such as blue light. If the consistency of blue light is not good, other wavelengths such as green light, yellow light, red light and infrared light can also be used, but the wavelength of the second light-emitting diode 12 is not greater than that of the first light-emitting diode 11.

[0039] To further improve the above scheme, a reflector is provided in the optical path of the backscattering structure. The reflector is used to partially reflect the light emitted by the second light-emitting tube into the receiving tube. The reflected background value is set to 10%~50% of the signal range of the receiving channel, providing a fixed smoke-free background signal for the receiving path. The smoke signal will fluctuate on this background signal. The above structure ensures that the backscattering has a constant background or base signal in the smoke-free situation. In the case of dense black smoke and water vapor, the significant absorption of the light source by the black smoke and water vapor causes the reduction in the base signal to be greater than the increase in the smoke backscattering signal, resulting in a smaller total received signal. In the case of thin smoke, the reduction in the base signal may be comparable to the increase in the smoke backscattering signal, resulting in no change or a slight decrease in the total received signal. However, the noise of the signal is higher than that in the smoke-free situation. The noise can be calculated using the root mean square noise method, that is, calculating the root mean square noise of the past n data points. Assuming the acquired signal X is expressed as... , , , n is generally the number of samples in the past 1 to 15 seconds. The noise of the smoke-free background signal depends only on the circuit's own noise, and when smoke, even thin smoke, enters, its signal fluctuation becomes larger, reflected in the larger root mean square noise, and through this simple method, thin smoke can be determined. The same method is not applicable to the first reflection tube, because the signal of thin smoke may be lower than the background noise of the data sampling circuit and be cut off, so it is difficult to detect.

[0040] As shown in one embodiment of Figure 2 : the second light-emitting tube 12 uses a red or infrared light-emitting tube, preferably the same infrared tube as the first light-emitting tube 11, and the reflection plate 314 is used to reflect the emitted light of the second light-emitting tube 12 to the receiving tube 2 to a certain extent. The presence of the reflection plate 314 does not interfere with the optical path of the first light-emitting tube 11 and the receiving tube 2, but only reflects part of the light of the second light-emitting tube 12 to the receiving tube 2. The requirement for the reflection plate 314 is that the intensity of the emitted light reaches 10%~50% of the receiving range of the receiving tube 10, and the reflection plate 314 only provides reflection, which is equivalent to the background signal in actual use and can be calibrated, so the process requirement is not high. The reflection plate 314 can be connected with other mechanisms or connected with the side wall mechanism of the smoke detector. Therefore, when the second light-emitting tube 12 is lit, there is always a constant light reflected by the reflection plate 314 to the receiving tube 2, regardless of whether there is smoke, Figure 2 , in which the light e is emitted from the second light-emitting tube 12 and reflected by the reflection plate 314 to the receiving tube 2. When the first light-emitting tube 11 is lit, the receiving tube 2 has no signal if there is no smoke. Therefore, the first light-emitting tube 11 and the receiving tube 2 still constitute a classic forward scattering, preferably using infrared light to provide better temperature consistency; and the second light-emitting tube 12 and the receiving tube 2 constitute a backscattering different from the classic design, artificially increasing the emission plate 314, and the second light-emitting tube 12 uses a red or infrared light-emitting tube, which has better temperature drift and stability, and can share the same power supply with the first light-emitting tube. Compared with using a blue light-emitting tube, one power supply can be reduced because the blue light-emitting tube needs a higher driving voltage under the same driving current. The above structure forms a double combination judgment method, in which the first light-emitting tube 11 and the receiving tube 2 constitute a forward scattering structure for regular detection, and the second light-emitting tube 12, the receiving tube 2, and the reflection plate 314 constitute a backscattering structure with constant reflection, providing a stable method for detecting black smoke, water vapor, and thin smoke.

[0041] As shown in one embodiment of Figure 1 and Figure 2In the shown embodiments, the second light emitting tube is located between the receiving tube and the first light emitting tube, and the three are located in a semicircle of 180°; the first light emitting tube and the receiving tube form forward scattering, and the included angle a between the main axes of the light paths is 120°-160°, which is equivalent to a scattering angle of 20°-60°; the second light emitting tube and the receiving tube form backward scattering, and the included angle b between the main axes of the light paths is 20°-60°, which is equivalent to a scattering angle of 120°-160°. The above structure reduces the area and volume of the optical device layout, further reduces the volume of the smoke detector, and meets the demand of the small space inside the battery pack.

[0042] The receiving tube, the first light emitting tube and the second light emitting tube are provided with light path limiting mechanisms on both sides. Thus, it is ensured that the light emitted by the first light emitting tube when there is no smoke will not be reflected to the receiving tube through the internal mechanism, and the scattered light generated by the smoke particles when there is smoke will be irradiated to the receiving tube; it is ensured that the light emitted by the second light emitting tube when there is no smoke will be emitted back to the receiving tube through the reflection plate to form a background signal, and the scattering generated by the smoke particles and the background signal will change at the same time when there is smoke. Figure 1 and Figure 2 In the shown embodiments, the first light emitting tube 11 has mechanisms 304 and 305 limiting the optical angle on both sides, the second light emitting tube 12 has mechanisms 306 and 307 limiting the optical angle on both sides, and the receiving tube 2 has mechanisms 308 and 309 limiting the receiving angle on both sides; the classic design idea is that the light emitting angle formed by the first light emitting tube 11 and the optical limiting mechanisms 304 and 305 will not be disturbed by other mechanisms, especially the mechanisms 308 and 309 are not in the light emitting angle, so that the light of the first light emitting tube 11 is avoided from directly shining and reflecting into the receiving tube 2; similarly, the light emitting angle formed by the second light emitting tube 12 and the optical limiting mechanisms 306 and 307 will not be disturbed by other mechanisms, especially the mechanisms 308 and 309 are not in the light emitting angle, so that the light of the second light emitting tube 12 is avoided from directly shining or reflecting into the receiving tube 2. The mechanism members 304, 305, 306, 307, 308 and 309 are schematic diagrams, and are preferably integrated with the plastic parts such as the smoke detector shell by injection molding, which is beneficial to improve the mechanical strength and anti-vibration performance; taking the mechanism members 304 and 305 as an example, the function is to limit the optical emission angle range of the first light emitting tube 11, so the specific design can be a mechanism member closely attached to the optical device or an E-shaped or comb-shaped inner wall facing the photoelectric device, which is a conventional practice in the art and will not be described in detail.

[0043] The PCB circuit board is also provided with N light emitting tubes, which form forward scattering structures or backward scattering structures with the receiving tube, and N is a natural number. The first reflection light, the second emitting tube and the receiving tube can also be integrated multi-in-one devices, so this scheme is not limited to the optical device layout of double emitting and single receiving.

[0044] The smoke detector adopts a minimalist design, and the fewer the shell and mechanism components, the better. Figure 3 Firstly Figure 1 and Figure 2 is the installation schematic diagram of the PCB circuit board 4, which has two installation modes: parallel installation to the installation plane (a) Figure 3 -(a) or vertical installation to the installation plane (b Figure 3 ). The preferred mode is to be installed in parallel to the inner wall of the installation plane of the smoke detector and to face the optical device towards the center of the earth, which has two beneficial effects: first, the height of the smoke detector relative to the installation plane depends on the height of the optical device, so that the smoke detector can be made very thin; second, the optical device is oriented or biased towards the center of the earth, which is beneficial for the discharge of water vapor and condensation.

[0045] Further, Figure 3 are two embodiments of the entire smoke detector: the main body of the smoke detector is limited within the cuboid range composed of length L, width W and height H, and one of the faces is selected as the installation plane, and the installation hole 10 is arranged on the extension plane of the installation plane, which is used to fix the smoke detector at a certain place of the battery pack, and the installation hole 10 can be placed in four directions according to the installation requirement.

[0046] Figure 3-(a) is the mode of installing PCB circuit board 4 parallel to the installation plane, PCB circuit board 4 is fixed on the installation plane using screws, and the right side of PCB circuit board 4 has connector 41 for communication with the car machine or BMS system, which is a vehicle connector. Therefore, the height of the entire PCB circuit board 4 depends on the height of the optical device. According to the above selection and considering the thickness of the mechanism, the height of the smoke detector maze can be limited to within 15 mm, and the typical value is 9 mm to 12 mm. Considering that the size of the vehicle connector is relatively large, the actual height of the smoke detector height may also depend on the height of the connector, but the overall height is less than 20 mm. If MOLEX connector 347933330800 is selected, the overall height may be about 16 mm, because the connector itself with the circuit board and pins is 13 mm high. Try to select a small connector. Considering the arrangement of the connector and the device, the length L of the smoke detector can be controlled within 70 mm, and the typical value is 50 mm to 60 mm; if the width of PCB circuit board 4 is controlled within 30 mm, the main body width W of the smoke detector can be controlled within 70 mm, and the typical value is 40 mm to 50 mm. PCB circuit board 4 is fixed on the installation plane, and the optical part facing the center of the earth is beneficial to discharge condensation and dust, avoiding accumulation on the optical device to cause measurement error. The part passing through the detection area 5 and perpendicular to the PCB circuit board 4 can become a smoke passage connected before and after the smoke detector, and the smoke detector shell is used. The louver-shaped air-permeable and light-proof structure. Connector 41 is located on PCB circuit board 4 and exposed to one side of the shell. The smoke detector is provided with an upper cover plate 81, and a middle partition plate 85 divides the smoke detector main body into upper and lower parts. The detection area 5 is opened, and the lower part is the air inlet and air collection space, and the upper part is the circuit board and device space. The mechanism prevents condensation from flowing into the circuit area. The upper half of the partition plate 85 is located on the left and right sides of the circuit board and perpendicular to the circuit board. The shell is shell 82 and shell 83, and the front and parallel to the circuit board. The shell is shell 88; the shell corresponding to the lower half of the partition plate 85 is shell 87, shell 86 and shell 89; the lower shell of the module is shell 84. These shell assemblies are only marked for ease of description. Actual products need to be combined with specific designs to minimize the number of mechanisms. One or more mechanisms are combined into one whole, which helps to improve the vibration reliability of the mechanism and facilitates assembly.

[0047] Figure 3 -(b) is the mode of installing PCB circuit board 4 perpendicular to the installation plane, PCB circuit board 4 is fixed on the middle partition plate 85 using screws, and the right side of PCB circuit board 4 has connector 41 for communication with the car machine or BMS system, which is a vehicle connector. With Figure 3The opening mode of (a) is different after the circuit board is rotated. The part of the PCB circuit board 4 that passes through the detection area 5 and is perpendicular to the PCB circuit board 4 can become a continuous smoke inlet passage from the top to the bottom of the smoke detector, and a louvered air-permeable and light-proof structure is adopted at the smoke detector housing. The connector 41 is located on the PCB circuit board 4 and exposed to the side of the housing. The smoke detector is provided with an upper cover plate 81, and the middle partition plate 85 divides the smoke detector body into two parts, the upper part is provided with an opening at the detection area 5, the lower part is an air inlet and air collection space, and the upper part is a PCB circuit board 4 and a device space, and the mechanism is moisture-proof to prevent condensation from flowing into the circuit area. The upper half of the partition plate 85 is located on the left and right sides of the circuit board and perpendicular to the circuit board, and the housing is an outer shell 82 and an outer shell 83, and the front and perpendicular to the circuit board is an outer shell 88; the shell corresponding to the lower half of the partition plate 85 is an outer shell 87, an outer shell 86 and an outer shell 89; the lower shell of the module is an outer shell 84. One or more of the shell of the lower half of the partition plate 85, the outer shell 87, the outer shell 86, the outer shell 89 and the outer shell 84 can be designed as a louvered air-permeable and light-proof structure, which is helpful for smoke introduction and water drainage and condensation removal under the action of gravity.

[0048] Figure 4 is Figure 1 and Figure 2 the optical layout and the circuit board plus the smoke detector housing are shown in the figure, wherein, Figure 4 (a) corresponds to Figure 1 and Figure 3 (a), Figure 4 (b) corresponds to Figure 2 and Figure 3 (a).

[0049] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A smoke detector horizontal labyrinth for a battery pack comprising a PCB circuit board, characterized in that: The PCB circuit board is provided with a receiving tube, a first light-emitting tube and a second light-emitting tube, which are arranged in parallel with the PCB circuit board and have their main optical axes also in parallel with the PCB circuit board; the receiving tube and the first light-emitting tube form a forward scattering structure, and the receiving tube and the second light-emitting tube form a backward scattering structure; the first light-emitting tube is an infrared light-emitting tube, and the second light-emitting tube is a blue light-emitting tube, a green light-emitting tube, a yellow light-emitting tube, a red light-emitting tube or an infrared light-emitting tube; A reflecting plate is arranged on the light path of the backward scattering structure, and the reflecting plate is used for reflecting the light emitted by the second light-emitting tube into the receiving tube; the reflecting background value of the reflecting plate is set to 10% to 50% of the signal range of the receiving channel, so as to provide a fixed smoke-free background signal for the receiving channel; When thin smoke enters, the fluctuation of the signal will become larger, which is reflected in the increase of the root mean square noise; the root mean square noise is used to judge the thin smoke; The presence of the reflecting plate does not interfere with the optical path of the first light-emitting tube and the receiving tube, but only reflects part of the light of the second light-emitting tube into the receiving tube; The second light-emitting tube is located between the receiving tube and the first light-emitting tube, and the three are located in a semicircle of 180°; the first light-emitting tube and the receiving tube form a forward scattering, and the included angle α between the main axes of the light paths is 120° to 160°; the second light-emitting tube and the receiving tube form a backward scattering, and the included angle β between the main axes of the light paths is 20° to 60°; Both sides of the receiving tube, the first light-emitting tube and the second light-emitting tube are provided with light path limiting mechanisms.

2. A horizontal smoke detector labyrinth for a battery pack according to claim 1, characterized in that: The PCB circuit board is parallelly mounted on the inner wall of the mounting plane of the smoke detector or is vertically mounted on the inner wall of the mounting plane of the smoke detector, and the optical emission directions of the first light-emitting tube and the second light-emitting tube are both towards the center of the earth.

3. A horizontal smoke detector labyrinth for a battery pack according to claim 1, characterized in that: The second light-emitting tube is not mounted.

4. A horizontal smoke detector labyrinth for a battery pack according to claim 1, characterized in that: The intersection of the optical axes of the receiving tube, the first light-emitting tube and the second light-emitting tube is a detection area, and the smoke inlet channel of the smoke detector is provided with two: one is the detection area and the area below it, and the other is the smoke inlet channel which passes through the detection area and is perpendicular to the PCB circuit board.

5. A horizontal smoke detector labyrinth for a battery pack according to claim 1, wherein: A partition is horizontally arranged in the middle of the smoke detector housing, the PCB circuit board is arranged above the partition, and an air inlet and a gas collection space are arranged below the partition.

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