Testing Chambers Knowledge

  Lithium ion power batteries have been widely used in the field of electric vehicles due to their high voltage, high specific energy, and good cycling performance.   1 Test Taking a lithium-ion power battery with a rated capacity of 70Ah for electric vehicles as an example, a room temperature (20 ℃) capacity test and a low temperature (-20 ℃) capacity test were conducted to compare the impact of temperature on the capacity of lithium-ion batteries.  The lithium-ion battery has a charging cut-off voltage of 36V and a discharge cut-off voltage of 2.0V. Then, discharge capacity tests are conducted in environments of 20 ℃ and -20 ℃, and the test is terminated when the discharge cut-off voltage is 2.0V.     2 Main factors affecting low-temperature capacity The low-temperature performance of lithium-ion batteries is mainly affected by the types of electrolytes, positive and negative electrode materials, etc.  The low-temperature performance of lithium-ion batt...

  The storage of lithium-ion batteries is very common in practice, and they may be stored for a long time during the production and sales cycle of the battery. In practical use, they may also be stored for a long time.  During the storage process of lithium-ion batteries, especially in high-temperature environments, the battery system is in a thermodynamic unstable state under full charge, and will continuously undergo a transition to an equilibrium state.  When the changes accumulate to a certain extent, it will not only cause changes in the voltage and internal resistance of lithium-ion batteries, but also affect the rate performance and safety characteristics.  Therefore, it is particularly important to study the storage performance of lithium-ion batteries in a certain environment. This article studies the performance degradation of lithium-ion batteries under full charge state and different temperature storage, including changes in voltage, resistance, capacity ...

  1.Possible causes of thermal runaway Energy storage batteries generally experience thermal runaway under abuse conditions, and common abuse conditions are divided into three categories: mechanical abuse, electrical abuse, and thermal abuse. The most common occurrence of thermal runaway due to electrical abuse. In abusive working conditions, lithium-ion batteries not only release reaction heat, ohmic heat, and polarization heat, but also include heat released by internal short circuits and heat released by reactions.  The heat released by internal short circuits and side reactions (including SEI membrane decomposition, positive and negative electrode electrolyte reaction, membrane dissolution, electrolyte decomposition) is much greater than the heat generated under normal operating conditions, which can lead to a rapid increase in battery temperature and easily lead to uncontrolled heating   (1) Mechanical abuse The main characteristic of mechanical abuse is the relative...

  With the popularization of new energy electric vehicles, the safety issues of electric vehicles are receiving increasing attention. Among them, the safety characteristics of lithium batteries are one of the key factors for the safety of electric vehicles.  This article takes ternary soft pack lithium batteries as the research object, and through experimental and simulation research, explores the safety characteristics of lithium batteries under different shapes of crush heads, different crush positions, and different initial state of charge (SOC) conditions.   The research results indicate that the sharper and narrower the shape of the crush head, the earlier the sudden temperature rise time of the lithium battery, the greater the sudden temperature loss, and the higher the internal resistance rise.  The closer the squeezing position is to the bottom edge of the lithium battery, the more likely the temperature rise is to cause thermal runaway. The closer the squeez...

With the popularization of electric vehicles and the continuous expansion of market share, safety issues have also become one of the focuses of consumer attention.  Especially the frequent occurrence of electric vehicle spontaneous combustion has attracted widespread attention and discussion in society. The occurrence of these events not only brings concerns to consumers, but also attracts the attention of car manufacturers and battery suppliers.   In general, the spontaneous combustion of electric vehicles is not an accidental event, but is caused by multiple factors.  Firstly, there are production defects in the battery itself, such as unreasonable internal structure and non-standard production process. These defects may cause internal short circuits in the battery cells, leading to spontaneous combustion accidents.  Secondly, external factors are also an important reason for the spontaneous combustion of electric vehicles. During the use of batteries, they may be ...