Lithium battery safety assessment and test method

　　Author ：Iflowpower – Portable Power Station Supplier

Safety assessment and test method of lithium ion battery. This year, the lithium-ion battery is frequently sent in electric vehicle power lithium battery. How to evaluate and test the safety of lithium-ion batteries, and better prevent the emergence of lithium-ion battery safety accidents has always been a point in the industry.

The temperature of the lithium-ion battery shows the thermal state of the battery, which exists, the essence of lithium ion batteries and heat transfer results. To study the thermal characteristics of lithium-ion batteries, and their heat and heat transfer characteristics in different states, we recognize an important way to exotherm chemical reactions in the lithium-ion battery. Insensus behavior of unsafe behavior, including battery overcharge, fast charge and discharge, short circuit, mechanical abuse conditions and high temperature heat shock, etc.

Passivation film of negative electrode and positive surface. When the electrical core temperature rises to 130 ¡ã C, the SEI film decomposes the surface of the negative electrode, resulting in a highly active lithium carbon negative electrode exposure to an intense redox reaction in an electrolyte, and the heat generating the battery enters a high risk state. When the internal temperature of the battery increases to 200 ¡ã C or more, the positive electrode surface passivation film decomposition is an oxygen, and continues to react a strong heat in the same electrolyte, a large amount of heat and form a high internal pressure.

When the battery temperature reaches 240 ¡ã C or more, a dramatic exothermic reaction with lithium carbon negative electrode is bonded. Lithium-ion battery safety assessment instrument in lithium ion battery safety research, calorimeter is the most important use instrument. The most commonly used thermometer is an accelerator thermometer, the English name is Accelerating Rate Calorime, ARC.

ARC is a new thermal analysis instrument recommended for dangerous goods assessment using the United Nations, which can supply chemical reactions under insulation conditions - temperature-pressure data. Arc is based on the insulation principle design, which can use a large sample amount, high sensitivity, and accurately measure the initial temperature of the sample, the temperature and pressure of temperature and pressure during the heat-insulating decomposition process, especially the differential scanning amount And the pressure of the material that cannot be given in thermal decomposition during thermal decomposition is slowly changed during thermal decomposition. The ARC security assessment method ARC prevents the calibration of the sample and the environment from being exchanged by accurate temperature tracking, so that an approximately adiabatic environment can be supplied to test the thermal conductivity of the sample test.

In addition to testing thermal out-of control, using ARC can supply thermal insulation environments, connect Arc and DC constant flow source, charge and discharge equipment, you can test the heat capacity of the battery than heat capacity and charge and discharge process. Temperature problem of lithium ion batteries About the safety of lithium ion batteries. The environment used itself is also a temperature, while the lithium ion battery will also occur when used.

It is important that the temperature will affect the chemical reaction inside the lithium ion battery, and the temperature is too high, and the service life of the lithium-ion battery will cause the safety of lithium-ion batteries in the case of severe cas.