What are the influence factors of lithium ion battery cycle performance?

The importance of the cycle performance of lithium ion battery needless to say, When use battery longer cycle life means less waste of resources. There are many factors that can influence the properties of lithium ion battery cycle, this article mainly from the following several aspects to explore. The use of raw materials species: the choice of materials is the first factor influence the properties of lithium ion batteries. The stand or fall of material performance, determines the cycle performance of battery, if the performance of the material is very poor, process more reasonable, the cycle of batteries must also cannot guarantee; From the Angle of material, the cycle of a battery performance, is by the positive electrode and the electrolyte, cathode and electrolyte match of the two, with poor person. Material cycle performance is poorer, on the one hand, is likely to be in circulation in the process of crystal structure change too fast to continue to complete the intercalated-li lithium, on the one hand may be due to the active substance and its corresponding electrolyte can't generate dense and uniform SEI film active material and electrolyte premature side reaction and make the electrolyte excessive consumption will affect cycle. In designing batteries, if a very confirm choose cycle performance with poor material, other do not need to choose cycle performance good material, waste. Compaction is negative: negative compaction is too high, although can improve the energy density of batteries, but also a certain extent, reduce the material cycle performance. If is negative compaction is too large, is not conducive to lithium ion embedded and emergence, may reduce the capacity of the battery, it will also make a battery cycle performance and ratio of performance degradation. Water: too much water will and adverse event happened is the cathode active material and electrolyte, undermine its structure, in turn, affect the circulation, make the adverse event in the plate surface reaction, effect of lithium ion embedding and emergence. Too much water also not conducive to the formation of the SEI film. If too much water, moisture inside the battery electrolytic, produce gas, make the air pressure inside the cell is too big, cause battery leakage, severe cases can lead to battery explosion-proof valve broken. But in difficult to remove traces of moisture at the same time, the trace amounts of water can also be a certain extent to ensure the performance of the batteries. Coated surface density: for the same as material of batteries with capacity with lower membrane density is equivalent to add a layer or multilayer winding or laminated layer, corresponding to the increase of the diaphragm can absorb more electrolyte in order to keep the cycle. Considering a thinner film density can increase rate performance of the batteries, the pole piece and naked batteries baked in addition to the water will be easier, but the presence of low density when the operator in the figure is hard to control the surface density, further affect the quality of the product and size of large particles may also cause more difficulties to the coating, rolling, and reduce the production efficiency and increase the difficulty of operating staff. , so improvements to the coated surface density of above to consider several factors. Negative excess: in the process of lithium battery cycle, anode materials continuously accept embedded lithium ion, after a long cycle, the cathode material of structure damage is serious. Therefore, when lithium battery design, we need appropriate excessive complex cathode materials. If negative excessive insufficient, lithium batteries may before the cycle is not analysis, but the positive structure change little circulation after hundreds of times but the cathode structure is destroyed and cannot receive the positive provide lithium, lithium ion to analyse cause premature capacity decline. Enough amount of electrolyte, electrolyte influence on the cycle there are three main reasons, one is the insufficient fluid injection rate, injection fluid amount is insufficient, the battery in the process of circulation. Lithium ion to normal conduction, leading to lithium ion to the normal conduction, thus reduce the capacity of lithium ion battery second, while the liquid injection amount but aging time enough or is negative because of the high compaction immersion is not sufficient, if insufficient cell infiltration, plate surface without electrolyte, the corresponding sheet was unable to play its corresponding g capacity, resulting in a loss of battery capacity. 3 it is inside the loop batteries electrolyte is depleted, the matching of positive negative especially in the cathode and the electrolyte micro characterized by dense and stable SEI formation, and in his right eye visible performance, both for the circulation of electrolyte in the process of consumption. Incomplete SEI film on the one hand, can not effectively prevent the cathode and the electrolyte are consumed by the side effects of electrolyte, on the one hand, on the SEI film for the defective parts will be as the cycle to regenerate the SEI film to consume the reversible lithium source and electrolyte. Whether the batteries of recycle hundreds or even thousands of times or for dozens of times both diving batteries, if cycle before the electrolyte electrolyte has consumed after adequate but cycle, increase electrolyte ownership is likely to a certain extent, to improve the cycle performance. Objective conditions of the test, the test in the process of charging and discharging rate, cut-off voltage, charge cut-off current, in the test charge and test room temperature, all of a sudden interruption in the process of testing, test points and outside factors, such as batteries, contact resistance will be more or less affect the cycle performance test result.