Some knowledge points of 18650 lithium ion battery production

18650 lithium ion battery has the advantages of light weight, large capacity (1.5~2 times of the same weight of nickel-hydrogen battery), low self-discharge rate, no memory effect, etc., so it has been widely used-many digital devices use lithium The battery is used as the power source, let's take a look at the 48v and 60V battery pack tutorial for 18650 lithium ion batteries. To assemble 48v and 60V battery packs, you must first know the capacity and voltage of the 18650 lithium-ion battery pack. Common rechargeable 18650 lithium-ion batteries, the voltage is standard 3.6 or 3.7v, the maximum is not more than 4.2v when overflowing, which has little to do with the power (capacity), the mainstream capacity of 18650 batteries ranges from 1800mAh to 2600mAh, (18650 The power battery capacity is mostly 2200~2600mAh), and the mainstream capacity even has the standard 3500 or 4000mAh or more. 18650 lithium-ion battery packs 48v battery pack, you need: 48÷3.7u003d12.97 pieces 48÷4.2u003d11.42 pieces In order to guard against excessive voltage after overcharge, take the middle value of 12, so 12 18650 lithium battery cells are connected in series, You can get a battery pack of about 48 volts. 18650 lithium ion battery pack 60V battery pack, you need: 60÷3.7u003d16.21 pcs, 60÷4.2u003d14.28 pcs, in order to guard against excessive voltage after overcharge, take the middle value of 15 pcs, therefore, only need 15 pcs of 18650 lithium battery Connecting the bodies in series, you can get a battery pack of about 60 volts. Of course, if you only take a set of 12 or 15 18650 lithium-ion batteries in series, then the capacity of the battery pack is only equal to the capacity of one battery; if you want the battery pack to have a large capacity, you need to make a few more sets 12 or 15 18650 lithium-ion batteries are connected in series. Then connect these battery packs in parallel to form a large battery pack, so that the capacity of the battery pack is large. For example, if the capacity of a single 18650 lithium-ion battery is 4000 mAh, then a 60v20000 mAh battery pack is required, then 20000÷4000u003d5 groups of 15 18650 lithium-ion batteries are required to make a series battery pack, then You need 5*15u003d75 18650 lithium-ion batteries. 18650 lithium-ion battery pack 48v and 60V battery packs need to pay attention to: 1. The battery pack needs lithium-ion battery protection board. Although it is simple to connect in series, it can increase the voltage like a stacked Arhat, but the lithium-ion battery is too delicate and dangerous It cannot be over-discharged or over-charged, that is, the charging voltage cannot be too high, otherwise it may explode, and it cannot be discharged at any cost, otherwise the battery will be damaged, so something is needed to protect over-charge or over-discharge , This is the lithium-ion battery protection board. 2. The battery pack should avoid excessive internal resistance and heat generation. Generally, the internal resistance of an 18650 single-cell lithium-ion battery is about 70 milliohms. If the battery is connected in series, the internal resistance will of course increase with the series connection, while the parallel connection is just the opposite. The greater the internal resistance, the greater the heat generation, the lower the efficiency, and the higher the temperature. If the temperature is higher than a certain value, the lithium-ion battery will be damaged. The connection of lithium-ion batteries is also a problem, because the battery shell is made of steel, and it is not good to weld with a general electric soldering iron. It is often necessary to use a special spot welder. If the welding is not good, it will increase the internal resistance of the battery pack. It is easy to cause heat during frequent charging and discharging, which may cause unexpected safety accidents. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Analysis of common process points of 18650 lithium batteries