Several factors affecting the recycling of Rechargeable Coin Battery

Several factors affecting the recycling of Rechargeable Coin Battery

22 Aug 2020

1. Moisture
Excessive moisture will cause side reactions of the positive and negative active materials in the button battery, destroy its structure and affect the cycle. At the same time, too much moisture is not conducive to the formation of SEI film, but it is difficult to remove trace moisture. Trace amounts of water can also guarantee the performance of Rechargeable Coin Battery to a certain extent.

2. Compaction of positive and negative poles
Excessive compaction of the positive and negative electrodes can increase the energy density of the Rechargeable Coin Battery cell, but it will also reduce the cycle performance of the material to a certain extent. In theory, the greater the compaction, the damage to the material structure will be The larger the size, the structure of the material is the basis for ensuring the recycling of lithium-ion batteries; in addition, Rechargeable Coin Battery cells with higher positive and negative electrode compaction are difficult to ensure a higher liquid retention capacity, and the retention capacity is the Rechargeable Coin Battery battery. The core is an important basis for completing normal cycles or more cycles.

3. The objective conditions of the test
During the test, the charge and discharge rate, cut-off voltage, charge cut-off current, overcharge and overdischarge during the test, temperature of the test room, sudden interruption during the test, test point and Rechargeable Coin Battery cell contact internal resistance, etc. Factors, more or less, will affect the results of the cycle performance test. In addition, different materials have different sensitivity to the above objective factors.

Rechargeable Coin Battery
4. Excessive negative electrode
Excessive negative electrode generally needs to consider the influence of the first irreversible capacity and the deviation of the coating film density, but also the influence on the cycle performance. For the lithium cobaltate plus graphite system, the negative electrode graphite becomes the cycle process. If the negative electrode is not sufficient, the Rechargeable Coin Battery cell may not desorb lithium before cycling.

In this way, the structure of the positive electrode changes little after hundreds of cycles, but the negative structure will not be completely damaged if the negative structure is severely damaged. Receiving the lithium ions provided by the positive electrode to precipitate lithium, which will easily cause premature decline in capacity.

5. Coating film density
It is almost impossible for a single variable to consider the influence of film density on the cycle. Inconsistent film density will result in a difference in capacity, or a difference in the number of layers of Rechargeable Coin Battery batteries or the number of laminated layers. For Rechargeable Coin Battery batteries of the same model, capacity and material, reducing the film density is equivalent to increasing the number of layers of one or more windings or laminations, so that the corresponding increase in the diaphragm can absorb more electrolysis

So as to ensure circulation. Taking into account that thinner film density can increase the rate performance of Rechargeable Coin Battery cells, it will be easier to bake and remove water from pole pieces and bare Rechargeable Coin Battery cells. Of course, the error of too thin film density during coating It may be more difficult to control. Large particles in the active material may also have a negative impact on coating and rolling. More layers means more foils and diaphragms, which in turn means higher costs and lower Energy density, so this assessment also needs to be balanced.

6. Types of materials
The choice of material is the first factor that affects the performance of lithium-ion batteries. If a material with poor cycle performance is selected, no matter how reasonable the process is in time, and the production is perfect, the cycle of Rechargeable Coin Battery cells cannot be guaranteed; a better choice Even if there are some problems in the subsequent production, the cycle performance may not be too bad. From the material point of view, the cycle performance of a full battery. Generally, it is determined by the poorer of the cycle performance after matching the positive electrode and electrolyte, and the cycle performance after matching the negative electrode and electrolyte.

The cycle performance of the material is poor. During the cycle, the crystal structure changes too fast, which leads to the inability to continue lithium insertion and removal. On the other hand, it may also be because the active material and the corresponding electrolyte cannot form a dense and uniform SEI film, which will cause the active material and electrolyte to pass The side reaction occurs early, causing the electrolyte to be consumed too quickly and affecting the circulation.

7. The amount of electrolyte
There are three main reasons why the insufficient amount of electrolyte will affect the circulation. The first is insufficient injection volume, and the second is that the injection volume is sufficient but the aging time is not enough, or the positive and negative electrodes are too high compacted, which causes the immersion of the liquid. Fully, the third is that the internal electrolyte of the Rechargeable Coin Battery cell is consumed as the cycle of the Rechargeable Coin Battery is completed.

The third point is that the microscopic performance of the matching of the positive and negative electrodes, especially the negative electrode and the electrolyte, is the formation of dense and stable SEI, while the naked eye The visible performance is not only the consumption rate of the electrolyte during the cycle, but the incomplete SEI film cannot effectively prevent the negative electrode and the electrolyte from causing side reactions to consume the electrolyte.

On the one hand, the defective part of the SEI film will follow the cycle. Thus, regenerating the SEI film will consume the reversible lithium source and electrolyte. Whether its Rechargeable Coin Battery cells that circulate hundreds or even thousands of times or Rechargeable Coin Battery cells that dive dozens of times, if the electrolyte is sufficient before the cycle and the electrolyte has been consumed after the cycle, increase the electrolyte The fluid retention is likely to improve its cycle performance to a certain extent.