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Li-ion Battery Crush Test

  Due to the limitations of materials, battery technology, and manufacturing processes, lithium ion batteries have always had a significant fire risk during their use. The safety of lithium ion batteries under collision and crush has always been a focus of attention.   Generally, the fundamental reason for a fire caused by external forces on a lithium ion battery is that an internal short circuit occurs inside the battery due to severe deformation and damage, resulting in severe electrochemical reactions and high heat generation inside the battery, ultimately leading to thermal runaway and combustion and explosion of the battery.   Researchers have obtained the failure behavior of cylindrical lithium ion batteries under different mechanical external forces through mechanical integrity experiments and numerical simulations. Some researchers have discovered the thermal runaway behavior of the 18650 lithium ion battery under various crush methods, and found that even if the ...
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Safety Evaluation System of Lithium ion Battery

  As lithium-ion batteries are widely used in aviation, aerospace, new energy vehicles and other fields, their safety risks and problems in the process of use are increasingly prominent.  Especially under abuse conditions (such as high temperature, short circuit, overcharge and discharge, vibration, extrusion and impact, etc.), they are prone to smoke, fire and even explosion.  Therefore, their safety indicators are also highly valued internationally. At present, a number of international organizations and countries in the world have introduced corresponding lithium battery standards and inspection requirements, and have investigated the safety performance of lithium ion batteries from different perspectives.  This paper discusses the safety standards of lithium-ion batteries, analyzes the test purposes and methods of different safety standards, and focuses on the analysis of the test methods and influencing factors of internal short circuit which has a great impact ...
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Lithium Battery Buring and Explosion Test

  Lithium-ion batteries are widely used in new energy vehicles. In recent years, the explosion accidents of new energy vehicles have caused widespread concern and attention to their safety. Lithium-ion batteries may burn and explode under extreme conditions such as overcharge, collision and high temperature, and it is very difficult to put out.   1.Analysis of buring process and characteristics of lithium-ion battery   Lithium-ion battery is mainly composed of positive electrode, negative electrode, diaphragm, electrolyte, shell and other components. The cathode material is usually lithium intercalated transition metal oxide or polyanion compound; The anode material is mostly graphite. The electrolyte is mainly composed of organic mixed solution and lithium salt. The diaphragm is mainly used to isolate the positive and negative materials, prevent the short circuit caused by the passage of electrons, and let the ions in the electrolyte pass through.  When the battery ...
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Safety Testing Standards for Power Li-ion Battery – Part 2

  1.5 Nail Penetration The nail penetration test evaluates the safety of the battery by penetrating the steel needle through the sample at a certain speed. The steel needle passes through the battery, damaging the integrity of the electrode and diaphragm, resulting in a short circuit in the battery and continuous heat generation.  The severity level of nail penetration test is relatively high, and only three of the standards introduced in this article include this test. According to the difference of the test samples, the test parameters (needle depth, steel needle diameter, needle speed, etc.) of the needle test are quite different. SAEJ2464 200 and GB/T31485-2015 both require the steel needle to remain in the sample for 1h after penetrating the sample, but FreedomCAR does not specify.   1.6 Rollover The rollover test simulates the rollover and overturn that the vehicle may encounter in an accident, which is also called rotation in some standards (UL2580-2013, SAEJ2929 2...
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Safety Testing Standards for Power Li-ion Battery – Part 1

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  In recent years, countries around the world have continuously increased policy support for new energy vehicles, and car companies such as Tesla have also launched new models. It has led to the rapid growth of the global electric vehicle market.  However, the fire and explosion accidents of electric vehicles have occurred many times, making the safety issue the focus of consumers. In this context, countries and relevant international organizations have issued standards for the safety testing of power batteries to standardize the safe use of power batteries.   At present, the international technical standards/specifications related to the safety of power batteries are shown in the figure. Among them, the standards issued by ISO (International Organization for Standardization), IEC (International Electrotechnical Commission) and SAE International (Society of Automotive Engineers) are international standards, which have strong reference significance for national standards, ...
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Lithium Battery Thermal Runaway Caused by Nail Penetration – Part 2

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  3.Comparison and analysis of nail penetration thermal runaway test Comparing the results of the six groups of tests, the batteries were damaged, but the severity of the tests was different. According to the different experimental characteristics, the experimental characteristics of nail penetration can be divided into three categories.   Category I: For example, the batteries in Group 1 and Group 5 only discharge electrolyte, without smoke and explosion;   Class II: For example, although the battery in Group 3 and Group 6 did not explode, a small amount of smoke and electrolyte were emitted from the pressure relief valve of the battery;   Category III: For example, the battery exploded and produced a large amount of smoke in the test of group 2 and group 3, which caused severe damage. It can be found that the result of thermal runaway caused by nail penetration is more random, but it has caused serious damage to the battery. In the first type of test results, the ...
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