Lithium-ion battery charging speed is fast or slow

As we all know, lithium batteries can be used in the process of use with the increase in the number of times of charging and discharging, its capacity will gradually develop less. Just like a we need to use a smart phone business, at first the power can be used all day, but because with the growth of different time of use in our country, the power is consumed more and more quickly. This is the reason why the capacity of lithium batteries in use in China is decreasing. Next, we will analyze and the effect of fast and slow charging on the decline of lithium batteries.

For quick replacements, this problem is relatively easy to solve. We may have replaced our cell phones before the batteries ran out, but for long-lasting products like electric cars, this is not an easy problem to solve.lithium ion battery VS lead acid battery Typically, the lifespan of an EV is about 10 years, during which time the car may need to be recharged 1,000 to 2,000 times (assuming charging every other day), and in order to work with EVs we have to set certain regulations for the life of the lithium-ion batteries in EVs.

There are many factors that affect the life of Li-ion batteries, including operating temperature, charge/discharge current, charge/discharge blocking voltage, etc. These all affect the life of Li-ion batteries. These all affect the rate of degradation of Li-ion batteries. The mechanisms of Li-ion battery capacity degradation can be divided into three categories: increase in internal resistance and polarization, loss of positive and negative active material, and loss of Li. External factors have different effects on these.

Discharge management systems for lithium-ion batteries exist that are heavily dependent on network users, and good discharge systems are not necessarily applicable to all student users in an organization. However, since the own charging agent is largely under the control of the designer, our study of the effect of the charging agent on the degradation of battery life better guides the design of Li-ion batteries.

In one test, we used commercial 18650 batteries with licoo2 for the cathode material and graphite for the anode material to test the effect of different charging currents on the rate of battery decay.lithium battery vs lead acid Charging current has a significant effect on the rate of decay of lithium-ion batteries. According to the charging ratio of 0.5c, the decay rate of the battery was 0.020%/loop for the first 150 cycles, 0.0156%/loop for 150-800 cycles, and 0.0214%/loop stabilized after 800 cycles. For a charging ratio of 0.8c, the battery's decline rate was 0.0243%/cycle for the first 150 cycles, 0.175%/cycle for 150-800 cycles, and 0.0209%/cycle after 800 cycles. For a 1c charging ratio, the decline rate is 0.032%/cycle for the first 150, 0.0188%/cycle for 150 to 600, and 0.0271%/cycle after 600. 1.2c charging results in a decline rate of 0.0472%/cycle for the first 100, and 0.0226%/cycle for 100 to 400. 0.0226%/cycle, and a decline rate of 0.0356%/cycle after 400 cycles. Compared to the different charging ratios, the 1.5c charge has a clear difference, with a much faster average decline rate than the other ratios. From the previously mentioned data, the rate of decline of the lithium-ion battery increases rapidly as the charging ratio increases. From the slope of the curve, the decay rate of the battery can be divided into three stages: the first stage with a faster decay rate (stage I), the middle stage with a slower and stable decay rate (stage II), and the later stage with an accelerated decay rate (stage III). Based on the study of the three-stage cell decay mechanism, the first stage may decay faster because the growth of the cell sei film consumes some Li. In the second stage, the sei film structure is stable and relatively internally stable, and therefore decays at a slower rate. In the third stage, the cell ages, loss of active material begins to occur, the electrode active interface decreases, and the cell is very sensitive to current response. Figure c shows the experimental results of the effect of different cutoff voltages on the cell decline rate. The test results show that increasing the cut-off voltage to 4.3v leads to a sharp decrease in the battery cycling performance, while decreasing the cut-off voltage effectively improves the battery cycling performance.

If the charging current is less than 1c, the dynamic internal resistance of the battery will vary almost identically with the battery cycle. However, if the charging current exceeds 1c, the rate of improvement in the dynamic internal resistance of the battery increases rapidly as the charging rate increases. When the charging blocking voltage is 4.3v, the dynamic internal resistance of the battery increases very rapidly, indicating that the high blocking voltage exacerbates the dynamic conditions of the battery. However, the dynamic internal resistance of the cell increases more slowly when the blocking voltage is 4.1v and 4.2v.

lithium batteries internal resistance cycling performance

0