Views: 160 Author: Site Editor Publish Time: 2023-07-05 Origin: Site
The battery testing chamber mainly simulates whether the battery will ignite, leak, explode, etc. when charged under a series of natural conditions such as high and low temperature, humidity, constant temperature and humidity. Due to the possibility of explosion during the testing process, there are certain requirements for the explosion-proof performance of the equipment. To adapt to a wider range of test samples. In order to prevent explosion, the concentration of combustible gases in the test chamber should be detected during simulation testing. When abnormalities are found, measures should be taken to reduce the concentration of combustible gases in the battery constant temperature and humidity test box to avoid accidents such as combustion and explosion.
1. Control Design of Battery Explosion Proof Test Box
Explosion is caused by intense chemical reactions such as combustion. To prevent combustion reactions of the sample in the battery explosion-proof test box during the testing process. When a small amount of combustible gas is initially detected in the box, the action of introducing fresh air can be designed in the control of the battery constant temperature and humidity test box. By introducing fresh air from outside, the concentration of combustible gas in the box can be maintained within the safe range. If serious situations such as open flames or explosions occur in the battery constant temperature and humidity test box, the temperature inside the box will rise sharply. At this point, fire extinguishing actions should be designed in the control of the test box to timely control and extinguish the fire inside the battery constant temperature and humidity test box, to prevent open flames and explosions from spreading outside the test box. Avoid causing damage to surrounding equipment, property, and personal injury or death.
When the combustible gas detection device of the battery constant temperature and humidity test box detects that the concentration of combustible gas in the test box reaches 400ppm, open the inlet and outlet valves. The ventilation fan and exhaust fan are started simultaneously, introducing fresh air from the outside into the equipment to dilute the concentration of combustible gas until it returns to below 400ppm. After continuously introducing fresh air for a period of time (which can be set by an external timer), the ventilation device stops working, and the test chamber does not stop working during this process.
2. Electrical design of battery explosion-proof test box
In order to realize the explosion-proof early warning detection in the battery explosion-proof test box, control the concentration of combustible gas in the test box, and Automatic fire suppression the fire after combustion and explosion, some special electrical designs are required.
2.1 Combustible gas sensor
Install a combustible gas concentration detection sensor at the front end of the battery explosion-proof test box. The sensor adopts a pumping structure. Take samples from the test chamber and extract gas for testing. The sample inlet is installed at the circulating air outlet inside the box. The combustible gas sensor panel can set and display two alarm points. When the concentration of combustible gas inside the box exceeds the set alarm point, the combustible gas sensor will issue a warning or danger alarm signal, and output the corresponding open circuit signal through its own output terminal.
To avoid fire, ordinary nickel chromium wire heaters cannot be used in the battery explosion-proof test box. Finned armored electric heaters must be used, and the armored pipes and fins are made of stainless steel material. The packaged heater will not generate open flames or cause secondary faults such as short circuits due to external forces such as explosions.
2.3 Automatic spraying C02 fire extinguishing device
In the event of a fire or explosion, the temperature inside the battery explosion-proof test box will rise sharply. This abnormal temperature change can be detected by special temperature sensors and transmitted to the control system of the test chamber. The system injects carbon dioxide by opening an electric valve. The high-pressure CO2 fire tank and electric valve body are installed on the outer wall of the box, and the nozzle is installed inside the box. In addition, "manual switch" and "cancel switch" are set on the operation display panel.
2.4 Temperature anomaly detection
Equipped with two temperature sensors that can be moved anywhere in the box to detect the surface temperature of the sample. When the surface temperature of the sample is abnormal and higher than the preset temperature, the red alarm light of the equipment and the overtemperature light of the box will light up simultaneously, and the equipment will stop running and cut off the sample power supply through the test power terminal.
2.5 Emergency stop switch
When the operator discovers an abnormality in the battery explosion-proof test box, they immediately press the emergency stop switch to stop the operation inside the test box, and cut off the secondary power supply of the test box through an AC contactor. However, the safety Q system (ventilation, CO2 injection, etc.) is not affected and operates normally.
2.6 Safety Q full operation device display panel
It is installed in a position where the equipment is easy to operate, on the right side of the front of the box. The ventilation device switch, CO2 fire extinguishing device manual automatic switch, emergency stop switch, gas alarm light, and abnormal temperature display light inside the battery explosion-proof test box are all installed here.
3. Structure of battery constant temperature and humidity test chamber
3.1 Reinforcement of battery constant temperature and humidity test box
100mm channel steel is used to strengthen the protection on the outer side of the battery explosion-proof test box to prevent severe deformation and damage caused by huge impacts, fire spread, and accidental damage from hard objects. The cover plate is divided into small pieces to avoid the position of the channel steel, making it convenient for daily maintenance of the test box in the disassembly and assembly room.
3.2 Safety Q full protective door
In addition to installing large doors with observation windows outside the battery explosion-proof test box, reinforced safety Q safety doors should also be installed. Be careful not to block the controller and observation window of the battery explosion-proof test box. The protective door is also equipped with a limit switch for door opening detection. When the safety Q protective door is opened, the test box stops running; The test box can only operate when the protective door is closed and the limit switch is closed.
3.3 Observation window
The design size of the observation window should not be too large. The outer ring and door of the test chamber can be fixed with double-layer stainless steel fasteners. In terms of glass material, tempered explosion-proof glass should be used, and a protective mesh should be installed outside the glass for protection to prevent glass fragments from injuring people during explosions.
3.4 Lead Hole
In addition to insulation rubber plugs, the lead hole should also be equipped with a threaded protective nut, and a small hole should be drilled on the nut. Embedded protective sleeve for threading. When the pressure inside the box rises sharply, the nut can prevent the rubber plug from flying out and injuring people.
3.5 Installation location
In order to avoid the pressure increase around the battery explosion-proof test box when it releases pressure, the installation site of the test box should be spacious and there should be no obstacles around the test box. To prevent secondary losses caused by fire and pressure relief in the laboratory, a certain distance should be reserved between the top of the test box and the laboratory roof.