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Foreword

China is the world’s largest producer of primary batteries and the second largest producer and exporter of lithium-ion batteries. Battery products are high-risk products. In all aspects of its production, storage, transportation, testing and use, there may be safety accidents such as ignition and explosion.

In recent years, China’s battery industry has developed rapidly, and battery product quality and safety have received widespread attention. Battery testing laboratories are also undergoing large-scale development. Due to the particularity of battery products, many testing items, such as thermal shock, heavy object shock, vibration, short circuit, overcharge and over-discharge, and forced reverse charging, are prone to explosion or even fire during the test.

For this reason, while paying attention to the quality and safety of battery products and improving the ability of battery testing technology, it is also necessary to pay attention to the safety protection measures of the laboratory itself. As far as possible, avoid harm to the inspectors and bring damage to national property.

Product Classification & Testing Items

According to the United Nations Recommendations on the Transport of Dangerous Goods, the classification rules for dangerous goods, battery products containing strongly acidic or strong alkaline electrolytes are Class 8 (corrosive) dangerous goods. Lithium batteries are Class 9 (Miscellaneous) dangerous goods.

The battery product safety testing items are divided into: (1) Intended use: high-altitude simulation, temperature cycling, vibration, low-rate charging, etc .; (2) Reasonably foreseeable misuse: external short circuit, heavy object impact, squeeze, mechanical impact, free fall, forced discharge, abnormal charging, thermal abuse, incorrect installation, over-discharge, overcharge, high rate charging Wait.

Hazardous Characteristics of Battery Products

In addition to lead-acid batteries, dangerous corrosive electrolyte spills may occur during transportation. During overcharging, a gas containing hydrogen and oxygen as main components is generated. It may cause the pressure of the battery to rise. If it encounters an open flame after the overflow, there is a danger of explosion and fire. It also includes the release of toxic gases such as arsine and antimony, and lead exposure hazards.

The qualified phenomena of lithium battery products during testing include:

Quality loss;

Leakage;

Release;

Short circuit;

Rupture;

explosion;

Fire and so on.

It’s worth noting that leaks or fires are accompanied by toxic gases.

Requirements for Laboratory Accreditation Guidelines

Precaution

Battery products, especially lithium batteries, have the danger of spontaneous combustion and explosion during storage, testing and transportation. For battery testing activities or laboratories, we must first establish the laboratory’s own safety precaution mechanism and develop effective preventive measures. And it is implemented in every step of sample storage and testing to prevent potential safety hazards to the greatest extent possible.

Facilities & Environmental Conditions

During the testing of battery products, especially during short circuit, overcharge, forced discharge, extrusion, and thermal abuse tests, the risk of explosion and fire suddenly increases. At the same time, the battery charge and discharge detection cycle is very long. Therefore, it is necessary for the battery testing laboratory to take effective personnel protection, area isolation, fire smoke extraction, remote monitoring and other measures.

Battery Laboratory Fire Protection System

Battery testing items are often dangerous and have long cycles. At the same time, batteries are chemically hazardous and require special fire extinguishing agents.

Common fire extinguishing agents:

Water fire extinguishing agent;

Foam fire extinguishing agent;

Dry powder fire extinguishing agent;

Carbon dioxide fire extinguishing agent;

Haloalkane fire extinguishing agent and so on.

These fire extinguishing agents have their own advantages and disadvantages, but not all of them are suitable for battery laboratories. Inert gas extinguishing agents are more costly. Therefore, it is more appropriate to configure an automatic fire alarm system and FM200 gas fire extinguishing system for centralized control of fires caused by batteries. Set up smoke and temperature detectors in each functional area, multiple methods (manual and automatic), multi-level control, high reliability.

Battery Laboratory Ventilation & Air Conditioning

According to the power mode of ventilation, it can be divided into the following two modes:

natural ventilation

Mechanical ventilation

In addition, mechanical ventilation can be divided into the following 2 modes:

Local ventilation (this mode is used for battery detection)

Fully ventilated

Smoke Extraction Measures in Battery Laboratory

The smoke exhaust measures can be divided into natural smoke exhaust and mechanical smoke exhaust. Mechanical smoke exhaust can be divided into local smoke exhaust and centralized smoke exhaust. The mechanical centralized smoke exhaust system usually consists of a smoke retaining wall, a smoke exhaust port, a fire exhaust valve, a smoke exhaust duct, a smoke exhaust fan, and a smoke exhaust outlet. For environmental protection, you can consider adding a dust collector before the smoke exhaust outlet to avoid direct discharge of toxic and harmful smoke and dust into the atmosphere.

Battery Laboratory Flameproof & Explosion-proof

Explosion protection, that is, the impact of the explosion is limited to a predetermined area.

Based on reasonable area planning, multi-stage flameproof measures are recommended:

Equipment-level flameproof measures;

Facility-level flameproof measures;

Personnel-level flameproof measures.

Explosion prevention and explosion prevention measures such as laboratory layout (test area and control area), equipment surrounding protective isolation (such as vibration, shock, collision equipment peripheral protective cover), and equipment’s own protective isolation to ensure that when battery samples explode Personal safety of test personnel.

In addition, explosion-proof measures should be taken. For the planning area prone to battery explosion, the battery laboratory adopts an explosion-proof pressure relief device from the design, forming a weak link to prevent the harm caused by the explosion.

Explosion Protection & Smoke Extraction of Battery Testing Equipment

The testing equipment needs to have sufficient flameproof mechanical strength. In particular, the part facing the operation area must not burst or damage the equipment. Therefore, to implement the structure and strength design, try to use a fully enclosed frame and steel box structure.

Additional explosion protection measures are:

Safety valves (such as several independently designed non-standard equipment and battery test cabinets);

Bursting discs (such as thermal shock boxes, high temperature explosion-proof boxes), etc. The smoke exhaust design mainly includes two function parts: smoke alarm and forced smoke exhaust and basic smoke exhaust facility linkage.

Remote Control of Battery Testing Equipment

Cooperate with the laboratory area planning, develop a special control method suitable for battery testing. Remote control of testing equipment through network, serial port or electrical wiring. Change the traditional testing habits to ensure the safety of valuable equipment and personnel. Here, dual-host (PC + PC / MCU / PLC / DSP) or single-host (PC + LU) remote control mode is mainly used.

Summary

Because the battery is prone to explosion or even fire during the test. Not only should we pay attention to the quality and safety of battery products and improve the ability of battery detection technology, but also need to pay attention to the safety protection measures of the laboratory itself. As far as possible, avoid harm to the inspectors. Therefore, a safe battery testing device is very important.