Battery testing is an important step in ensuring the safety, reliability, and performance of batteries. Due to the inherent hazards of batteries (such as short circuits, leakage, and corrosion), the testing process also hides various safety risks, such as the use of large mechanical auxiliary equipment, high current charging and discharging systems, and simulation experiments under extreme environmental conditions. It is worth conducting in-depth research to ensure the safety protection of battery testing , ensure the personal safety of laboratory personnel, and ensure the property safety of instruments and equipment.
Based on the above viewpoint, the author of this article categorizes the testing items of batteries, analyzes the potential hazards during the testing process according to the conditions of project implementation, and proposes practical and feasible safety protection measures to address these hazards.
1 Classification of battery testing items
Battery testing items can generally be divided into four categories:
- Appearance inspection: appearance, polarity, overall dimensions, quality, etc;
- Electrical performance testing: room temperature discharge capacity, room temperature rate discharge capacity, charge retention and capacity recovery capacity, storage and cycle life, etc;
- Environmental adaptation performance testing: high and low temperature discharge capacity, high-altitude simulation, constant humidity and heat, vibration resistance, and salt spray resistance;
- Safety performance test: mechanical shock, drop, nail penetration, extrusion, collision, temperature shock, temperature cycle, external fire immersion, overcharge, overdischarge, external short circuit and heat abuse.
The above testing items can also be divided into normal use tests, foreseeable misuse tests, and abuse tests. Normal use tests: high-altitude simulation, temperature cycling, vibration, and low rate charging; Predictable misuse tests: external short circuit, heavy object impact, machine impact, drop, forced discharge, abnormal charging, incorrect installation, over discharge, over charging, and high rate charging; Abuse tests: nail penetration, squeezing, and external burning. The danger level of the latter two types of tests is higher than that of normal use tests.
2 Potential hazards of battery testing
Once the battery is used and stored improperly, there is a risk of combustion and explosion. In addition, there are certain safety risks associated with the use of testing equipment. The main hazards during battery testing include fire and explosion, liquid leakage, gas leakage, noise and vibration, mechanical hazards, and electrical hazards.
2.1 Fire and Explosion
Battery ignition and explosion are usually caused by external factors such as puncture, compression, overcharging, high temperature, and short circuit, which can cause internal or external short circuits in the battery and cause chemical reactions between electrode materials and electrolyte. Such as the decomposition of solid electrolyte phase interface (SEI) film, the oxidation and reduction of organic electrolyte, the decomposition of positive electrode, and the further reaction of oxygen generated from the decomposition of positive electrode with organic electrolyte. If the large amount of heat generated by these reactions cannot be dissipated into the surrounding environment in a timely manner, it will inevitably lead to thermal runaway, ultimately leading to battery combustion and explosion.
Lead acid batteries use dilute sulfuric acid as the electrolyte, which has a certain degree of corrosiveness. During the testing process, if the battery casing is damaged and electrolyte leakage occurs, it will pose a significant danger to personnel and equipment; Lithium ion batteries use organic electrolytes, which can cause gas emissions, pungent odors, and contain toxic substances during safety testing.
2.3 Noise and Vibration
The noise during battery testing mainly comes from such items as vibration, mechanical shock, collision and drop. Among them, vibration and collision are continuous noise, while mechanical shock and drop are instantaneous noise. The electrical performance testing equipment of batteries often uses air cooling, and the operation of fans can also generate noise. The vibration mainly comes from vibration tests and collision tests.
2.4 Mechanical Hazards
In the tests of mechanical shock, heavy object impact, vibration, collision and drop, the clamping looseness is easy to occur, causing the battery to fly out and causing damage to personnel; In addition, the operation process of the aforementioned mechanical equipment itself carries certain risks.
2.5 Electrical Hazards
Electrical performance testing items such as capacity and cycle life require long-term continuous operation of the equipment, which poses certain safety hazards; In addition, there is a possibility of battery reverse connection or short circuit during the battery connection process.
3 Safety protection requirements and measures
3.1 Personnel Protection
Personnel protection is of utmost importance. Inspectors who directly come into contact with samples and equipment are not only implementers of safety protection, but also objects of safety protection. Take all possible measures to ensure the safety of personnel. Minimize contact as much as possible, and avoid contact if possible. Personnel training should be strengthened to enhance safety protection awareness and ability; Protective equipment is required, and it is strictly prohibited to conduct hazardous or hazardous project testing without wearing protective equipment; The monitoring area and testing area should be appropriately separated, and remote controlled equipment should be used as much as possible.
3.2 Sample Protection
The protection of samples is mainly during storage. To maintain a dry environment, stable and moderate temperature; Insulate and protect the electrodes to prevent accidental short circuits; Regular inspections should be conducted to eliminate potential hazards immediately upon discovery; Proper classification and isolation should be carried out to prevent mutual influence.
3.3 Equipment Protection
The protection of equipment, on the one hand, should ensure that the equipment functions normally; On the other hand, it is necessary to prevent unexpected events from affecting the equipment. Strengthen inspection and maintenance, and regularly remove dust from charging and discharging detection equipment; Regularly remove dust and lubricate mechanical equipment such as vibration tables and impact tables; Regularly check whether the alarm function is normal; Install safety protection facilities such as protective nets; For equipment that has been out of service for a long time, it is necessary to cut off water and power
3.4 Environmental Protection
When abnormal conditions occur in a closed test environment (such as an environmental test chamber), the test should be stopped. After obtaining evidence (such as taking smoke and fire images), the fire should be effectively extinguished and exhaust gases should be discharged through the dedicated exhaust channel of the box. The testing room should be equipped with smoke detectors, fire extinguishers, sandboxes, fire hydrants, and other fire-fighting facilities. After obtaining evidence, the discarded batteries must be harmless treated according to the instructions of the sample supplier and relevant laboratory specifications, or submitted to a professional organization for reasonable disposal according to relevant regulations and procedures.
Reasonably layout each area based on the different characteristics of the testing project. Electrical performance testing has little impact on the environment and high safety. It can be arranged in areas with more personnel activities, but the testing sample area, equipment operation area, and monitoring observation area should be isolated;
Dangerous testing items such as nail penetration and overcharging can be arranged in remote and well ventilated areas; Testing items with high noise such as vibration and collision can be arranged in remote areas. If conditions permit, some safety space should also be reserved. Design a system for safety protection. Establish sound and feasible safety operation guidance procedures, emergency response procedures for emergencies, and personnel training procedures. To have a preliminary understanding of the types and performance of batteries, and based on this, to determine the safety of the testing project.
The safety protection of the laboratory can be approached from two aspects: management system and hardware facilities. With the continuous development of battery testing technology, the continuous improvement of laboratory management standards, and the continuous improvement of battery safety, the safety factor of battery testing laboratories will continue to improve.