How does the lithium-ion battery charger know if the battery is full?

How does the lithium-ion battery charger know whether the battery is full? First of all, it is necessary to ensure that the lithium-ion battery charger is matched with the electrical appliance to be charged, voltage matching and current matching, voltage matching is very important, and the current indicator of the charger is bumpy. Charging time, the higher the current index, the faster the charging speed; for example, 3A is faster than 1A. The second is that the general rule of the contest is that the indicator light of the charger may change the color of the light on the electrical appliance, generally from red to green gradually, that is, full of confession. The other is a bit professional, that is, measuring the voltage of electrical appliances, the difference in battery power, its terminal voltage is not communicated, the less power, the lower the voltage, so the voltage of the battery has a range, so that the electrical appliance can be used normally. The lower limit of the battery to full power may be like this: For example, the mobile phone uses a lithium-ion battery, and the working voltage range is 3.7~4.2V; assuming the power is divided into three divisions: when the lithium-ion battery voltage is 3.7~3.8V, the battery is empty, and the battery alarm ; When the battery voltage is 3.8~3.9V, one division; when the lithium-ion battery voltage is 3.9~4.1V, two divisions; when the battery voltage is 4.1~4.2V, the display is full. A good quality charger will determine whether it is full by detecting the voltage and current. But if it is a low-quality charger, it probably won't do this. It is completely relied on the lithium-ion battery's own over-current and over-voltage protection to charge. It will automatically cut off the current until the battery itself detects the over-voltage, and then report that you are charged. . Generally, the charger is constant current charging. Smart lithium-ion battery chargers usually take a while rather than instantly to be able to determine whether the battery has just been fully charged. Lithium-ion batteries can be judged directly according to the battery voltage. When the voltage is higher than the set cut-off voltage (usually 4.2V), the battery is considered to be full; the higher-level charger recycles the voltage and current to determine the connection. When the voltage is close to the cut-off voltage, switch to constant voltage charging. When the current is less than a certain set value, the battery is considered to be full. This is determined by the charger's determination method. At this moment, the mainstream and generally accepted methods to determine the accuracy of the competition are important-△V and 0△V. Therefore, the general middle and high-end lithium-ion battery chargers are based on these two determination methods, but after the battery is placed in the charger and charging starts, Regardless of whether the battery is charged or not, whether it is fully charged or not, the battery will not appear immediately. It may be said that it is sufficient-△V may be 0△V, but it will take a while to appear or it will be sufficient. The -△V determined by the charger may be 0△V, so it takes a while for the smart charger to determine that it is a fully charged battery. On the contrary, the lithium-ion battery charger judged by the first-level voltage contest method can determine the fully charged battery in a short time. This is because the voltage contest charger only judges the battery voltage. As long as the battery voltage is reached, it is It doesn't matter whether the battery is really full, it is judged to be full. In general, there is still a lot of room for the battery to reach saturation, that is, it is not really full. Therefore, this determination method is generally only used on the most advanced lithium-ion battery chargers. In the process of lithium-ion battery charging, there is a cut-off current and a cut-off voltage, which are higher than any one. The city causes irreversible damage to the battery. Therefore, the charging process can be understood as follows: first constant current charging and detecting the battery voltage at the same time. When the battery voltage is close to the cut-off voltage, it starts to enter the constant voltage charging stage. At this time, the charger starts to detect the charging current again, and the charging current becomes more and more. When the charging current is lower than the threshold value, the charger stops outputting, and the charging is regarded as complete. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Do you know anything about the fundamental requirements of lithium-ion battery chargers?