Failure analysis and introduction of lithium-ion batteries

Source: 2020 - 04 - 01 14:53 hits: lithium battery failure analysis and introduced definition: '( Defects) Product loss adjusting function '. For can repair products, this is often referred to as defects. 'the essence of the lithium battery failure is due to certain causes battery function attenuation or dysfunction. Function failure refers to the function of the lithium battery cannot meet the operation requirements and related indicators, first of all have capacity attenuation or tripping, cycle life is short, multiplier function is poor, poor consistency, self-discharge, high and low temperature function attenuation; Refers to the lithium battery security failure due to improper use or misuse of the failure, has certain security risks, such as heat loss, gas expansion, liquid leakage, lithium analysis, short circuit, expansion deformation, etc. Failure analysis aims to identify and prevent the happening of the failure. Failure analysis is to distinguish the product failure method, this paper analyzes the reasons of failure, failure phenomenon of a kind of speculation or prevent technology and handling activities. Of lithium battery performance indicators put forward higher requirements, especially in volume/mass energy density, power density, cycle life, cost, safety, etc. For example, in '2025' made in China, energy type of lithium battery can than more than 300 Wh/kg, and power type lithium ion batteries than can be greater than 4000 W/kg. Figure 2 is 1990 - Lithium ion battery energy density map in 2025. In order to meet market demand, the function of the battery, and security to move forward, and shorten the development cycle of the new system, it is necessary for the opening of lithium-ion batteries fault is analyzed. Although the birth of the products with failure, but failure is people learned from the failure phenomenon, so the failure analysis work should start from the failure phenomenon. The first step from the fault phenomena of lithium-ion batteries. Lithium battery failure phenomenon is the first step in the lithium battery failure analysis, it is also one of the most direct, the most important fault information. Lithium battery is not fully understanding and analysis of the failure information will not be able to accurately it is concluded that the root cause of the lithium battery failure, not only can provide constructive Suggestions or reliability. Failure phenomenon is divided into two parts, dominant failure and implicit. Advantage refers to the performance and characteristics of directly visible, such as failure and field investigation by thick depending on the analysis of damage and deformation of the surface structure, including the fire burning, fever, swelling ( Gas) , deformation, seepage, packaging materials, burr, damage and deformation virtual welding or leak welding encapsulation materials, plastic raw materials melting deformation, etc. Recessive refers to the fact that cannot be observed directly but need through the decomposition and analysis may be shown in the experiment to imitate the performance and characteristics, such as micro failure detection laboratory disassembly, and electric information of the battery. Lithium battery failure process middling some hidden failure phenomenon is negative short circuit, the formation of lithium, pole piece powder, diaphragm, diaphragm, dry film puncture, electrolyte, electrolyte degeneration failure, anodic dissolution, transition metal ( Copper) Separation, burr, winding ( Or laminated) Obstacles, scuba diving, ability and the disturbance of high voltage, resistance, cycle life disorder, high/low temperature dysfunction, etc. The failure phenomenon of planning often overlap with invalidation methods of planning. Failure phenomena tend to be more directly describes the failure phenomena, this is due to the information collection and description of failure process. Failure method is generally understood as the nature and type of failure, failure classification and distinction. Lithium battery failure is battery failure of a large cluster, it is necessary to carry out its definition and classification.