8/12/2019 Lithium-ion battery cycle performance factors affecting Discussion.docx

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Moisture:Excessive moisture will be positive and negative electrode active materialand side reaction occurs, and thus affect the structure of the destruction cycle, whiletoo much water is not conducive to the formation of the SEI film. However, whiledifficult to remove traces of water, traces of water can be guaranteed to some extent,the performance of batteries.

Coated film density:Consider the impact of a single variable density film cycle isalmost an impossible task. Film density inconsistencies or differences in the capacityto bring either batteries or winding difference laminated layers. With the samecapacity of the same material type batteries, the lower the density of the filmcorresponds to an increase or a wound layer or layers laminated layers,corresponding to the increase of the electrolyte membrane can absorb more toensure circulation. Considering the thinner the film density can be increased rateperformance of batteries, and the bare core pole piece of baking will be easier toremove water, of course, the density of the coating film is too thin, the error may bedifficult to control when the active substance large particles may also be coated,rolled a negative impact, more layers means more foil and diaphragm, in turn means

higher costs and lower energy density. Therefore, when assessing the need tobalance considerations.

Negative excess:Excess addition causes a negative initial irreversible capacity toconsider the impact of the deviation and the coating film density than the impact onthe cycle performance is also a consideration. For lithium cobalt oxide and graphitesystem, the negative cycle of graphite become "short board" one of the morecommon. If negative excess is not sufficient, batteries may not analyzed beforecycling lithium, but hundreds of times the loop structure is minimal but the positiveand negative changes in the structure was severely damaged but not completelypositive reception thus providing lithium-ion analysis of lithium, resulting in over-

capacity early fall.

Electrolyte volume:Produce insufficient amounts of electrolyte circulation affectthree main reasons, one less than the amount of fluid injection, the second injectionfluid volume is adequate, but despite the lack of time or aging infusion due to thepositive and negative electrodes and other causes excessive compaction is notsufficient, the third is with cycle batteries inside the electrolyte is consumed. Noteinadequate and insufficient fluid volume fluid volume Paul wrote, "electrolytedeficiencies on the performance of batteries" before and therefore not repeat them.On the third point, the negative electrode and the positive and negative electrolyteparticular microscopic matching dense and stable performance of SEI formation andperformance of the visible eye, both for circulation of the electrolyte during theconsumption rate. Incomplete SEI film on the one hand and the electrolyte can noteffectively prevent the occurrence of negative side effects and thus consume theelectrolyte, while the SEI film with defective parts will be re-circulated in order togenerate the SEI film and electrolyte depletion reversible lithium source . Whethercirculating hundreds or even thousands of times the batteries or both diving fordozens of batteries, the electrolyte is sufficient and if the first cycle after cycle hasbeen consumed electrolyte, the electrolyte increased ownership is likely to be someenhance the cycle performance degree.

Test objective conditions:Testing during charge-discharge rate, cut-off voltage,the charging cut-off current, tests overcharge and over discharge, the test room

temperature, the sudden interruption during the test, the test point and the contactresistance of batteries and other external factors that will or less impact cycle

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performance test results. In addition, the sensitivity of different materials to theabove objective factors varies, uniform testing standards and understand thecharacteristics of the common and important materials should be sufficient daily use.

To sum up:The same principle as the barrel, the factors affecting the performanceof batteries circulation among many, the ultimate decisive factor is a number offactors in the shortest board. Meanwhile, among these factors, but also have areciprocal influence. In the same materials and made capacity, the higher thecirculation, often means lower energy density, to find exactly the point of integrationto meet customer needs, try to ensure the consistency of batteries made of party isthe most important task lies .