Lithium Battery Knowledge
Different types of batteries have different internal resistances. For the same type of battery, due to the inconsistent internal chemical characteristics, the internal resistance is also different. The internal resistance of the battery is very small, we generally use milliohm units to mean it. Internal resistance is an important technical indicator to measure battery performance. Under normal circumstances, a battery with a small internal resistance has a strong high-current discharge capability, and a battery with a large internal resistance has a weak discharge capability. In terms of the schematic diagram of the discharge circuit, we can dissect the battery and the internal resistance and divide it into a power supply with no internal resistance connected in series with a small resistance......
The overwhelming majority of 18650 lithium batteries are encapsulated in steel shells. Due to the lack of protection, over-charged batteries will suddenly increase their internal pressure and explode when they exceed the withstand value. Short circuit, excessive temperature or squeezing or even puncturing the battery may cause the battery to explode.
Parallel connection: Several batteries, the positive electrode and the positive electrode, the negative electrode and the negative electrode are connected together side by side, the voltage remains unchanged, the capacity increases, and the corresponding current also increases.
Serial connection: Several batteries are connected in series, that is, the positive electrode and the negative electrode. The negative electrode of the first battery is connected to the positive electrode of the second battery, and so on. The voltage increases, the capacity does not change.
Generally, a 3.7V lithium battery needs an overcharge and overdischarge protection circuit board. If the battery does not have a protection board, it can only be charged with a voltage of about 4.2V, because the ideal full charge voltage of the lithium battery is 4.2V, and the voltage may be damaged if it exceeds 4.2V. The battery is charged by this method and the battery status needs to be monitored at all times.
Lithium batteries are widely used in people's lives, such as digital products such as cameras and notebook computers, as well as some other electrical appliances.
Tips for safe transportation of lithium batteries:
Lithium-ion batteries will face the risk of excessive self-discharge during long-term storage, especially at lower open-circuit voltages. Due to excessive self-discharge, the voltage of the lithium-ion battery may be too low, causing negative and negative copper foils dissolution and other risks, because the dissolved copper element will be precipitated on the surface of the negative electrode again during the charging process, the generated metal copper dendrites may pierce the separator, causing a short circuit between the positive and negative electrodes, so excessive discharge or low voltage will cause lithium The ion battery completely failed.
Lithium-ion batteries have been commercialized since the 1990s. Nowadays, they have entered the daily life of ordinary people. We use mobile phones, tablets, smart watches, VR glasses, digital cameras and other portable electronic products, almost all use lithium-ion batteries.
The lithium-ion battery protection board current is determined by the detection voltage of the protection IC and the internal resistance of the MOS tube. If the protection IC cannot be changed, you can change the MOS tube, such as DW01 and 8205MOS, using a MOS tube is 2 ~ 5A, using two The MOS tube parallel current will double. At present, some large-capacity mobile power supplies use 3 to 4 MOS tubes in parallel.
How many model names does the lithium battery have? In fact, it's not clear at this time, because each battery manufacturer has its own model specifications and some custom battery models. The following introduces the name of the lithium-ion battery model and the meaning of the letters and numbers on the battery, so that everyone can better understand the battery model specifications.
At present, most of electronic products use lithium-ion batteries, and a few years ago, electronic products mostly used nickel-cadmium batteries. These two batteries have different memory effects. The so-called memory effect means that during the first few charges, if it stops before being fully charged, the battery will remember the previously charged capacity when charging in the future.