CN220209060U

CN220209060U - Early detection alarm device for fire disaster of lithium ion battery

Info

Publication number: CN220209060U
Application number: CN202320766531.6U
Authority: CN
Inventors: 陈钦佩; 罗昊; 于东兴
Original assignee: Tianjin Fire Research Institute of MEM
Current assignee: Tianjin Fire Research Institute of MEM
Priority date: 2023-04-10
Filing date: 2023-04-10
Publication date: 2023-12-19
Anticipated expiration: 2033-04-10

Abstract

The utility model discloses an early detection alarm device for fire disaster of a lithium ion battery, which comprises a battery box, wherein a battery placing seat is arranged in the battery box, a plurality of containing grooves for placing the lithium ion battery are formed in the top surface of the battery placing seat at equal intervals, force sensitive resistors are arranged on the inner walls of two adjacent containing grooves, which are close to each other, the outer walls of the left side and the right side of the battery placing seat are symmetrically provided with openings, collectors are arranged in the battery box, a controller is arranged on the outer wall of the battery box, temperature detection assemblies are symmetrically arranged on the inner walls of the left side and the right side of the battery box, and two groups of gas detection assemblies are arranged on the outer wall of the battery box; according to the utility model, the temperature detection assembly is used for detecting the temperature of the outer side surfaces of the lithium ion battery monomers at the outermost sides of the front end and the rear end, and the detection position of the infrared temperature sensor can be changed so as to discover the position with overhigh local temperature in time, and further, the audible and visual alarm is used for alarming to remind a worker to check and maintain, so that the structure is simple and the practicability is high.

Description

Early detection alarm device for fire disaster of lithium ion battery

Technical Field

The utility model relates to a detection alarm device, in particular to a lithium ion battery fire early detection alarm device.

Background

The lithium ion battery is a secondary battery (rechargeable battery) and mainly works by means of movement of lithium ions between a positive electrode and a negative electrode, and the lithium ion battery is very active in chemical characteristics, so that the lithium metal is processed, stored and used, the environmental requirements are very high, along with the development of scientific technology, the lithium ion battery has become the mainstream, the lithium ion battery is small enough for daily use mobile phones, bluetooth headphones, smart watches and other wearable devices, the power sources of electric bicycles, electric automobiles and deep sea detectors, space detection power sources, unmanned power of various purposes and the like, the lithium ion battery is ubiquitous in various fields of the modern society, meanwhile, fire disasters caused by the lithium ion battery are visible everywhere, the lithium ion battery is filled with electrolyte, the electrolyte belongs to class A combustible liquid, the class A combustible liquid is easy to catch fire, and if the vapor of the electrolyte is concentrated, and the mixed gas with air reaches the explosion limit, explosion accidents can happen.

As described in an authorized publication number CN 209150260U, a plurality of lithium ion battery cells are sequentially arranged and fixed, the same battery interval is reserved between adjacent battery cells, and then a force sensitive resistor is arranged in the battery interval, so that the design can only detect the surface between the adjacent battery cells, but the detection of the outer side surfaces of the battery cells at the outermost sides of the front end and the rear end is omitted, and the distance between the plurality of adjacent battery cells is too close, if one of the batteries heats due to internal short circuit, the electrolyte is heated and expanded, the electrolyte steam is sprayed out to catch fire, other adjacent batteries can be heated rapidly, the fire occurrence speed and the battery damage severity are accelerated, and the detection alarm effect of the design scheme on the lithium ion battery is not good; therefore, we design a fire early detection alarm device of lithium ion battery to solve the above technical problems.

Disclosure of Invention

The utility model aims to provide a fire early detection alarm device for a lithium ion battery, which aims to solve the problems in the background technology.

In order to achieve the above purpose, the present utility model provides the following technical solutions:

the utility model provides a lithium ion battery conflagration early detection alarm device, includes the battery box, and the activity of battery box top is equipped with the chamber door, is equipped with the battery in the battery box and places the seat, and the equidistant holding tank that is used for placing lithium ion battery that has offered of battery placement seat top surface, and the inner wall that two adjacent holding tanks are close to each other all is equipped with the force-sensitive resistance, the opening has been seted up to the outer wall symmetry of the left and right sides of seat is placed to the battery, and the opening communicates with the holding tank of adjacent one side, is equipped with the collector in the battery box, and the battery box outer wall is equipped with the controller, the inner wall symmetry of the left and right sides in the battery box is equipped with temperature detection subassembly, and the battery box outer wall is equipped with two sets of gaseous detection subassembly.

The temperature detection assembly comprises a motor, a main gear, a pinion, a connecting rod, a connecting block, an infrared temperature sensor and an audible-visual alarm, wherein the motor is symmetrically arranged on the outer wall of the left side and the right side of the battery box, an output shaft of the motor stretches into the battery box and is connected with the main gear, the main gear is rotationally connected with the inner wall of the battery box, the pinion meshed with the main gear is arranged above the main gear and rotationally connected with the inner wall of the battery box through a rotating shaft, the connecting rod is fixedly connected with the edge of one side surface of the pinion, which is far away from the rotating shaft, of the connecting rod, the other end of the connecting rod is fixedly connected with the connecting block, the connecting block is slidably connected with the inner wall of the battery box, the infrared temperature sensor is fixedly arranged on one side surface of the connecting block, and the audible-visual alarm is respectively arranged on the outer walls of the left side and the right side of the battery box.

The gas detection assembly comprises a fan, a fan housing, a first air pipe, a second air pipe, a detection box, a wind exhaust nozzle, a flow dividing block, an ion smoke detector, a temperature and humidity detector and a sound and light alarm, wherein the fan is embedded in the outer wall of the battery box, the detection box is arranged on the outer side surface of the battery box, one end of the detection box is connected with the first air pipe, the other end of the detection box is connected with the second air pipe, the other end of the air pipe stretches into the battery box, the fan is fixedly sleeved with the fan housing, one end of the air pipe, far away from the detection box, is connected with the fan housing, the wind exhaust nozzle is positioned in the detection box, the wind exhaust nozzle comprises a diffusion nozzle and a shrinkage nozzle, the smaller end of the diffusion nozzle is connected with the first air pipe, the shrinkage nozzle is connected with the second air pipe, the flow dividing block is arranged between the diffusion nozzle and the shrinkage nozzle, the inner space of the detection box is divided into an upper part and a lower part by the flow dividing block, the inner top wall of the detection box is provided with the ion detector, the inner bottom wall of the detection box is provided with the temperature and the sound and light alarm.

As a preferred embodiment of the present utility model: the battery box is characterized in that the inner walls of the left side and the right side in the battery box are symmetrically provided with slide rail grooves, the slide rail grooves are of circular ring structures, a sliding block is fixedly arranged in the middle of one side of the connecting block, which is far away from the infrared temperature sensor, and the sliding block is slidably embedded into the corresponding slide rail groove.

As a still further preferred embodiment of the present utility model: a plurality of first through holes are symmetrically formed in the front side wall and the rear side wall of the accommodating groove, the first through holes are distributed at equal intervals along the vertical direction of the inner wall of the accommodating groove, and a plurality of second through holes are formed in the inner bottom wall of the accommodating groove at equal intervals along the length direction of the inner bottom wall of the accommodating groove.

As a still further preferred embodiment of the present utility model: the battery box is characterized in that a plurality of electric push rods are arranged on the inner bottom wall of the battery box and correspond to the accommodating grooves one by one, the electric push rods are located right below the bottoms of the corresponding accommodating grooves, and the extension ends of the electric push rods vertically extend upwards into the accommodating grooves.

As a still further preferred embodiment of the present utility model: the four corners of the bottom of the battery placing seat are respectively provided with a supporting leg, and the bottoms of the supporting legs are fixedly connected with the inner bottom wall of the battery box.

As a still further preferred embodiment of the present utility model: the two groups of gas detection assemblies are respectively positioned at the left end of the bottom of the front side surface of the battery box and the right end of the top of the rear side surface.

Compared with the prior art, the utility model has the beneficial effects that:

1. according to the utility model, through the cooperation of the opening, the first through hole, the second through hole, the battery placing seat and the temperature detecting assembly, the motor drives the main gear to rotate, the auxiliary gear is driven to rotate, the connecting block is driven to rotate through the connecting rod, the connecting block is made to perform circular motion by taking the rotation center of the auxiliary gear as the circle center, when the infrared temperature measuring sensor is driven to perform circular motion, the outer side surfaces of the lithium ion battery monomers at the outermost sides of the front end and the rear end are subjected to temperature detection, the detection position of the infrared temperature measuring sensor can be changed, so that the position with the local temperature being too high can be found in time, and further, the first audible and visual alarm is used for alarming to remind a worker to check and maintain, so that the structure is simple and the practicability is high; the plurality of holding grooves are arranged at a certain distance from each other, and when a dangerous accident occurs to one battery, other batteries beside the battery can not be influenced rapidly, or the speed of the other batteries is slowed down, so that the loss is minimized as much as possible.

2. According to the utility model, through the gas detection assembly, the smoke and the temperature and the humidity of the gas can be measured respectively, if the smoke concentration and the temperature and the humidity are detected to exceed the standard, the audible and visual alarm II is started to give an alarm, the monitoring personnel is reminded, and the two groups of gas detection assemblies are in a diagonal distribution design, so that the detection alarm effect of the device on the lithium ion battery is further improved.

Drawings

Fig. 1 is a top sectional view of a battery case according to the present utility model;

FIG. 2 is an enlarged view of FIG. 1 at A;

FIG. 3 is an enlarged view at B in FIG. 1;

fig. 4 is a front sectional view of a battery case in the present utility model;

FIG. 5 is a schematic view of the structure of the inner bottom wall of the accommodating groove according to the present utility model;

wherein: the intelligent electric energy-saving device comprises a 1-battery box, a 2-controller, a first 3-through hole, a 4-battery placing seat, a 5-containing groove, a 6-lithium ion battery, a second 7-through hole, a 8-supporting leg, a 9-electric push rod, an 11-ion smoke detector, a 12-split block, a second 13-air pipe, a 14-air exhaust nozzle, a 15-temperature and humidity detector, a second 16-audible and visual alarm, a 17-detection box, a first 18-air pipe, a 19-fan housing, a 20-fan, a 21-motor, a first 22-audible and visual alarm, a 23-connecting rod, a 24-connecting block, a 25-infrared temperature measuring sensor, a 26-opening, a 27-auxiliary gear, a 28-main gear and a 29-sliding rail groove.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Referring to fig. 1-5, in the embodiment of the utility model, an early detection alarm device for fire disaster of a lithium ion battery comprises a battery box 1, a box door is movably arranged at the top of the battery box 1, a battery placing seat 4 is arranged in the battery box 1, a plurality of containing grooves 5 for placing the lithium ion battery 6 are formed in the top surface of the battery placing seat 4 at equal intervals, force sensitive resistors are respectively arranged on inner walls, close to each other, of two adjacent containing grooves 5, openings 26 are symmetrically formed on outer walls of the left side and the right side of the battery placing seat 4, the openings 26 are communicated with the containing grooves 5 on the adjacent side, a collector is arranged in the battery box 1, a controller 2 is arranged on the outer wall of the battery box 1, temperature detection assemblies are symmetrically arranged on the inner walls of the left side and the right side of the battery box 1, and two groups of gas detection assemblies are arranged on the outer wall of the battery box 1.

The collector is used for collecting the resistance value of each force-sensitive resistor in real time, the controller 2 is used for judging whether the resistance value of each received force-sensitive resistor is in a preset safety threshold range or not, if not, corresponding early warning and protection are carried out, the principle is the same as that recorded in a comparison document with an authorized notice number of CN 209150260U, the details are not described in the prior art, but the plurality of accommodating grooves 5 are arranged at intervals, when a dangerous accident occurs to one battery, other batteries beside can not be influenced rapidly, or the speed affecting other batteries is slowed down, and the loss is reduced to the lowest possible.

The temperature detection assembly comprises a motor 21, a main gear 28, a pinion 27, a connecting rod 23, a connecting block 24, an infrared temperature sensor 25 and an audible and visual alarm I22, wherein the motor 21 is symmetrically arranged on the outer walls of the left side and the right side of the battery box 1, an output shaft of the motor 21 stretches into the battery box 1 and is connected with the main gear 28, the main gear 28 is rotationally connected with the inner wall of the battery box 1, the pinion 27 meshed with the main gear 28 is arranged above the main gear 28, the pinion 27 is rotationally connected with the inner wall of the battery box 1 through a rotating shaft, the connecting rod 23 is fixedly connected with the edge of one side surface of the pinion 27 far away from the rotating shaft, the other end of the connecting rod 23 is fixedly connected with the connecting block 24, the connecting block 24 is in sliding connection with the inner wall of the battery box 1, the infrared temperature sensor 25 is fixedly arranged on the surface of one side of the connecting block 24 close to the opening 26, and the audible and visual alarm I22 are respectively arranged on the outer walls of the left side and the right side of the battery box 1; the motor 21 drives the main gear 28 to rotate, and then drives the pinion 27 to rotate, drives the connecting block 24 to rotate through the connecting rod 23, makes the connecting block 24 do circular motion with the rotation center of the pinion 27 as the centre of a circle, and then drives the infrared temperature measurement sensor 25 to circulate and do circular motion, detects the temperature of the outside surface of the battery monomer at the front end and the rear end, and can change the detection position of the infrared temperature measurement sensor 25 so as to discover the local temperature too high position in time, and then alarms through the audible and visual alarm 22 to remind the staff to check and maintain, and the structure is simple and the practicability is high.

The inner walls of the left side and the right side in the battery box 1 are symmetrically provided with slide rail grooves 29, the slide rail grooves 29 are in a circular ring structure, a sliding block is fixedly arranged in the middle of one side of the connecting block 24 far away from the infrared temperature measuring sensor 25, and the sliding block is slidably embedded into the corresponding slide rail groove 29; this design helps to improve the stability of the connection block 24 during circular motion, i.e., to improve the stability of the device in use with the components inside the device.

The gas detection assembly comprises a fan 20, a fan housing 19, a first air pipe 18, a second air pipe 13, a detection box 17, a wind exhaust nozzle 14, a diversion block 12, an ion smoke detector 11, a temperature and humidity detector 15 and a sound and light alarm second 16, wherein the fan 20 is embedded in the outer wall of the battery box 1, the detection box 17 is arranged on the outer side surface of the battery box 1, one end of the detection box 17 is connected with the first air pipe 18, the other end of the second air pipe 13 extends into the battery box 1, the fan housing 19 is fixedly sleeved on the outer surface of the fan 20, one end of the first air pipe 18, far from the detection box 17, is connected with the fan housing 19, the wind exhaust nozzle 14 is positioned in the detection box 17, the wind exhaust nozzle 14 comprises a diffusion wind nozzle and a shrinkage wind nozzle, the smaller end of the diffusion wind nozzle is connected with the first air pipe 18, the shrinkage wind nozzle is connected with the second air pipe 13, the diversion block 12 is arranged between the diffusion wind nozzle and the shrinkage wind nozzle, the diversion block 12 divides the inner space of the detection box 17 into an upper part and a lower part, the ion smoke detector 11 is arranged in the detection box 17, the top wall of the detection box 17 is connected with the wind exhaust nozzle 17, the wind exhaust nozzle is connected with the sound and light alarm second wind detector 16, the sound and light alarm 16 is arranged on the inner wall of the detection box 17, and the wind detector 17 is arranged on the inner wall of the wind pipe 17; starting a fan 20, wherein the fan 20 continuously sucks the gas in the battery box 1 into a detection box 17, the gas is dispersed through a diffusion tuyere and then is divided into an upper gas and a lower gas through a flow dividing block 12, the gas at the upper side is detected through an ion smoke detector 11, the gas at the lower side is detected through a temperature and humidity detector 15, the gas is subjected to smoke and temperature and humidity measurement, the measured gas is converged into a second air pipe 13 through a contraction tuyere and is returned into the battery box 1, and if the smoke concentration and the temperature and humidity are detected to exceed the standard, a second audible and visual alarm 16 is started to give an alarm to remind monitoring personnel; the device discharges the detected gas back into the battery box 1 to ensure the concentration of various substances in the gas in the battery box 1, and if a potential fire disaster occurs, the device can be detected and found in time.

The two groups of gas detection assemblies are respectively positioned at the left end of the bottom of the front side surface and the right end of the top of the rear side surface of the battery box 1; the two groups of gas detection components are distributed in a diagonal manner, so that the detection alarm effect of the device on the lithium ion battery is further improved.

A plurality of first through holes 3 are symmetrically formed in the front side wall and the rear side wall of the accommodating groove 5, the first through holes 3 are distributed at equal intervals along the vertical direction of the inner wall of the accommodating groove 5, and a plurality of second through holes 7 are formed in the inner bottom wall of the accommodating groove 5 at equal intervals along the length direction of the inner bottom wall; the arrangement of the first through hole 3 and the second through hole 7 is favorable for timely exhaust, and when the lithium ion battery 6 is deteriorated, various gases and smoke are timely dispersed out through the first through hole 3 and the second through hole 7, so that the gas detection assembly can conveniently and rapidly detect the gases and timely make corresponding alarm and early warning.

Support legs 8 are arranged at four corners of the bottom of the battery placing seat 4, and the bottoms of the support legs 8 are fixedly connected with the inner bottom wall of the battery box 1; the battery placing seat 4 is supported by the supporting legs 8, so that a small space is reserved below the bottom of the battery placing seat 4, and the gas flow in the device is facilitated.

The inner bottom wall of the battery box 1 is provided with a plurality of electric push rods 9, the electric push rods 9 are in one-to-one correspondence with the accommodating grooves 5, the electric push rods 9 are positioned right below the bottoms of the corresponding accommodating grooves 5, and the extension ends of the electric push rods 9 vertically extend upwards into the accommodating grooves 5; the lithium ion battery 6 can be pushed to move upwards by the extension of the electric push rod 9, so that the unloading of the lithium ion battery 6 is facilitated.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present utility model may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.

Claims

1. The early detection alarm device for the fire disaster of the lithium ion battery comprises a battery box (1), wherein a box door is movably arranged at the top of the battery box (1); the method is characterized in that: a battery placing seat (4) is arranged in the battery box (1), a plurality of containing grooves (5) for placing lithium ion batteries (6) are formed in the top surface of the battery placing seat (4) at equal intervals, force sensitive resistors are arranged on the inner walls of two adjacent containing grooves (5) which are close to each other, openings (26) are symmetrically formed in the outer walls of the left side and the right side of the battery placing seat (4), the openings (26) are communicated with the containing grooves (5) on the adjacent side, a collector is arranged in the battery box (1), a controller (2) is arranged on the outer wall of the battery box (1), temperature detection assemblies are symmetrically arranged on the inner walls of the left side and the right side of the battery box (1), and two groups of gas detection assemblies are arranged on the outer wall of the battery box (1);

the temperature detection assembly comprises a motor (21), a main gear (28), a pinion (27), a connecting rod (23), a connecting block (24), an infrared temperature measurement sensor (25) and an audible-visual alarm I (22), wherein the motor (21) is symmetrically arranged on the outer walls of the left side and the right side of the battery box (1), an output shaft of the motor (21) stretches into the battery box (1) and is connected with the main gear (28), the main gear (28) is rotationally connected with the inner wall of the battery box (1), the pinion (27) meshed with the main gear (28) is arranged above the main gear (28), the pinion (27) is rotationally connected with the inner wall of the battery box (1) through a rotating shaft, the connecting rod (23) is fixedly connected with the edge of one side of the pinion (27) far away from the rotating shaft, the connecting block (24) is fixedly connected with the other end of the connecting rod (23), the connecting block (24) is slidably connected with the inner wall of the battery box (1), the infrared temperature measurement sensor (25) is fixedly arranged on the surface of one side of the connecting block (24) close to an opening (26), and the audible-visual alarm I (22) is arranged on the outer walls of the left side and right side of the battery box (1);

the gas detection component comprises a fan (20), a fan cover (19), a first air pipe (18), a second air pipe (13), a detection box (17), an exhaust nozzle (14), a flow dividing block (12), an ion smoke detector (11), a temperature and humidity detector (15) and a sound and light alarm (16), the fan (20) is embedded in the outer wall of the battery box (1), the detection box (17) is arranged on the outer side surface of the battery box (1), one end of the detection box (17) is connected with the first air pipe (18), the other end of the detection box is connected with the second air pipe (13), the other end of the second air pipe (13) extends into the battery box (1), the fan (20) is fixedly sleeved with a fan cover (19), one end of the first air pipe (18) far away from the detection box (17) is connected with the fan cover (19), the exhaust nozzle (14) is positioned in the detection box (17), the exhaust nozzle (14) comprises a diffusion nozzle and a shrinkage nozzle, the smaller end of the diffusion nozzle is connected with the first air pipe (18), the smaller end of the shrinkage nozzle is connected with the second air pipe (13), a flow dividing block (12) is arranged between the diffusion nozzle and the shrinkage nozzle, the flow dividing block (12) divides the inner space of the detection box (17) into an upper part and a lower part, the inner top wall of the detection box (17) is provided with an ion smoke detector (11), the inner bottom wall of the detection box (17) is provided with a temperature and humidity detector (15), and the outer wall of the detection box (17) is provided with a second audible and visual alarm (16).

2. The lithium ion battery fire early detection alarm device according to claim 1, wherein: the battery box is characterized in that the inner walls of the left side and the right side in the battery box (1) are symmetrically provided with slide rail grooves (29), the slide rail grooves (29) are of a circular ring structure, a sliding block is fixedly arranged in the middle of one side, far away from the infrared temperature measuring sensor (25), of the connecting block (24), and the sliding block is slidably embedded into the corresponding slide rail groove (29).

3. The lithium ion battery fire early detection alarm device according to claim 2, wherein: a plurality of first through holes (3) are symmetrically formed in the front side wall and the rear side wall of the accommodating groove (5), the first through holes (3) are distributed at equal intervals along the vertical direction of the inner wall of the accommodating groove (5), and a plurality of second through holes (7) are formed in the inner bottom wall of the accommodating groove (5) at equal intervals along the length direction of the inner bottom wall.

4. A lithium ion battery fire early detection alarm device according to claim 3, wherein: the battery box (1) is characterized in that a plurality of electric push rods (9) are arranged on the inner bottom wall of the battery box (1), the electric push rods (9) are in one-to-one correspondence with the accommodating grooves (5), the electric push rods (9) are located right below the bottoms of the corresponding accommodating grooves (5), and the extension ends of the electric push rods (9) vertically extend upwards into the accommodating grooves (5).

5. The lithium ion battery fire early detection alarm device according to claim 1, wherein: the four corners of the bottom of the battery placing seat (4) are respectively provided with a supporting leg (8), and the bottom of each supporting leg (8) is fixedly connected with the inner bottom wall of the battery box (1).

6. The lithium ion battery fire early detection alarm device according to claim 1, wherein: the two groups of gas detection assemblies are respectively positioned at the left end of the bottom of the front side surface and the right end of the top of the rear side surface of the battery box (1).