Welcome to Shenzhen Xin Ningbo Electronic Technology Co., Ltd.
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Shenzhen Xin Ningbo Electronic Technology Co., Ltd.
Address: 3rd Floor, No.49, Area 1, Yuanlin Village, Shiyan Town, Bao'an District, Shenzhen, China
1, material moisture
Excessive moisture can cause side reactions with positive and negative active materials, destroy its structure, and affect circulation. At the same time, too much moisture is not conducive to the formation of SEI film. However, while trace amounts of water are difficult to remove, trace amounts of water also occur. To a certain extent, the performance of the cell can be guaranteed.
2, positive and negative pressure compaction
If the positive and negative electrodes are compacted too high, although the energy density of the cell can be increased, the cycle performance of the material will be reduced to some extent. From theoretical analysis, the larger the compaction, the greater the structural damage to the material, and The structure of the material is the basis for ensuring that the lithium battery pack can be recycled; in addition, it is difficult to ensure a higher liquid holding capacity for the batteries with higher positive and negative poles, and the liquid holding capacity is that the batteries complete the normal cycle or more times. The basis of the cycle.
3, the objective conditions of the test
The external factors such as charge/discharge rate, cut-off voltage, charge cut-off current, overcharge/discharge during test, temperature of test room, abrupt interruption during test, contact resistance of test point and cell, etc. Or less affect the test results of the cycle performance, in addition, different materials have varying degrees of sensitivity to the above-mentioned objective factors, unified testing standards and understand commonalities and characteristics of important materials should be enough for daily work.
4, anode excess material
The reason why the negative electrode is excessive is that in addition to considering the influence of the first irreversible capacity and the deviation of the coating film density, the influence on the cycle performance is also a consideration. For the lithium cobalt oxide plus graphite system, the negative electrode graphite becomes a “short board” in the cycle. "One side is more common, if the negative electrode is not sufficient, the battery may not precipitate lithium before the cycle, but after a few hundred cycles, the structure of the positive electrode changes little but the structure of the negative electrode is severely damaged, and lithium ions provided by the positive electrode cannot be fully received for analysis. Lithium caused a premature drop in capacity.
5, coating film density
Considering a single variable, the effect of membrane density on the cycle is almost an impossible task. The inconsistent membrane density either results in a difference in capacity, or a difference in the number of cell windings or laminations, for the same type and capacity of the same material. In terms of batteries, reducing the film density is equivalent to adding one or more layers of windings or laminations. The corresponding increase in the number of separators can absorb more electrolyte to ensure circulation. In consideration of the thinner film density, the number of cells can be increased. The rate performance, pole piece and bare cell are also easier to bake and remove water. Of course, too thin film density may be more difficult to control when coated, and large particles in the active material may also be coated and rolled. Pressure has a negative impact. More layers means more foils and membranes, which in turn means higher costs and lower energy density. Therefore, a balanced assessment is also needed.
6, material types
The choice of materials is the first factor influencing the performance of lithium battery packs. The materials with poor cycle performance are selected. The process is reasonable and the production is perfected again. The cycle of the cell core must not be guaranteed; better materials are selected even if the follow-up There are some problems, the cycle performance may not be too ridiculously poor, from the material point of view, a full battery cycle performance, after the positive electrode and electrolyte matching cycle performance, negative and electrolyte matching cycle Performance, which is determined by the poorer one, results in poor cycle performance of the material. On the one hand, the crystal structure may change too quickly during cycling so that lithium delithiation cannot be completed. On the one hand, it may be due to activity. The material and the corresponding electrolyte cannot produce a dense and uniform SEI film, causing premature reaction of the active material with the electrolyte, causing excessive consumption of the electrolyte and further affecting circulation. In the design of the cell, if one pole confirms that the material with poor cycle performance is used, the other pole does not need to select a material with good cycle performance and waste.
7, the amount of electrolyte
There are three main reasons why the amount of electrolyte is insufficient to affect the cycle. First, the amount of liquid is insufficient. Second, although the amount of liquid is sufficient but the aging time is not enough or the positive and negative electrodes are not fully immersed due to excessive compaction, the third is With the circulation of electrolyte inside the core is consumed. The third point is that the microscopic performance of the positive and negative electrodes, especially the matching of the negative electrode and the electrolyte, is the formation of a dense and stable SEI, while the visible behavior of the right eye is not only the consumption rate of the electrolyte during the circulation but also the incomplete SEI. On the one hand, the membrane cannot effectively prevent the negative electrode and the electrolyte from undergoing a side reaction to consume the electrolyte. On the other hand, the SEI film is regenerated as the cycle proceeds to consume the reversible lithium source and the electrolyte. Whether it is for a cell that circulates hundreds or even thousands of times, or for a cell that does not hop for several tens of times, if the electrolyte is sufficient before the circulation and the electrolyte is consumed after the cycle, it is possible to increase the amount of electrolyte retained. To improve its cycle performance.
National Service Hotline
Shenzhen Address: 3rd Floor, No.49, District 1, Yuanlin Village, Shiyan Town, Bao'an District, Shenzhen, China
Hubei Yichang Address: Century Avenue, New Industrial Base, Zengdu District, Suizhou City, Hubei Province
Hubei No. 2 Factory Address: Opposite to the Seventh Party Police Station, Qifang Town, Zaoyang City, Hubei Province (side 316 National Road)
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