Lithium battery fire prevention method

Lithium batteries are generally classified into lithium metal batteries and lithium ion batteries. Lithium-ion batteries are more widely used because of their changeability and high energy density. The safety of lithium-ion batteries is a bottleneck to inhibit the development of lithium-ion batteries and related industries such as new energy vehicles. The electrolyte inside the lithium-ion battery is a flammable liquid, and the electrode is a combustible material. In the case of overcharge, short circuit, overheating, puncture or collision of lithium batteries, the heat is out of control, and it is easy to catch fire or even explode. Cases of fires caused by battery fire in mobile phones, electric bicycles or electric cars have occurred from time to time.

The author has 20 years of experience in the fire protection industry and has extensive exchanges with domestic and foreign counterparts. Starting from 2012, he began to study the fire prevention of lithium-ion batteries for electric bicycles and electric vehicles. This article shares several fire prevention solutions for lithium-ion batteries.

Introduction to lithium battery fire protection strategy

Lithium battery fire protection requires the establishment of multiple lines of defense with strategic depth. In addition to the use of non-flammable or flame-retardant materials inside the battery to make the battery intrinsically safe, the first line of defense outside the battery is to prevent various causes of battery overheating, such as overcharge, short circuit, impact, etc. The electrical system needs to be designed safely.

When the first line of defense is broken (for example, the battery management system fails to cut off the charging power supply in time), the battery temperature rises, and the temperature sensor or gas, smoke detector, etc. in the monitoring system should promptly find the fault and alarm, reminding the work. Personnel handles failures and eliminate fire incentives. This is the second line of defense.

When the fault is not dealt with in time and the second line of defense is broken, the battery burning (smoldering) is unavoidable. At this time, the file system needs to limit the combustion to the defective battery box (or box). It also isolates adjacent unfired batteries and equipment to avoid fire isolation. Due to the extremely high temperature of the lithium-ion battery after the thermal runaway, the existing non-aqueous fire extinguishing agents such as gas and dry powder cannot quickly lower the battery temperature, and the fire extinguishing effect is not ideal. Therefore, setting the battery fire prevention target to controlled burn-down is a relatively realistic solution with a strong technical economy. This is the third line of defense.

If the fire control failure expands and poses a serious threat to the safety of personnel, it is necessary to start a fixed water-based fire-extinguishing system installed in the vehicle or wait for the fire brigade to extinguish the fire.

In general, the first and second lines of defense are considered by battery manufacturers or electric vehicle manufacturers. As a fire protection professional, we can establish a solid third line of defense for our customers. We can customize the solution according to the specific model specifications of the battery. The components used in the program come from all over the world, not limited to certain equipment or material.

Lithium battery fire protection program example

This plan draws lessons from foreign advanced experience, simple and easy to carry out. The main composition of fireproof materials used for granular minerals, non-combustible, non-conductive, non-corrosive, safe and environmental protection, lightweight, reliable performance and reasonable cost, can be widely used in the production, storage, transport and use of lithium battery fire extinguishing process. After the lithium battery is burned by heating or overcharged heat, under the protection of fireproof particles, no open flame is generated, no explosion occurs, and only white smoke is emitted, so that the fire caused by the burning of the lithium battery can be avoided.

Fire prevention principle: isolation of oxygen asphyxiation, endothermic cooling

Particle size: 1-4mm Particle density: 360kg/m³ Dry bulk Weight: 240kg/m³

Lithium battery transportation fire prevention program

In order to ensure the effectiveness of fire control, a separate fire extinguishing tube can be installed in the battery case (or box). The fire extinguishing tube is thermally broken after the battery is on fire and the fire extinguishing gas is automatically released, and the battery fire is extinguished.

In addition, water-based fire extinguishing agents for lithium-ion batteries can be used to spray through fire extinguishers or fixed fire-fighting systems.

The page contains the contents of the machine translation.