How to assemble 48V electric vehicle battery with 18650 lithium battery

To boost voltage, we need to connect in series. We know that the essence of a calculator is a binary code like 01. Each unit can be refined to a single flip-flop. Multi-billion-level flip-flops can form very complex and very fast arithmetic logic. Human computing power is many times more powerful. The 18650 is just a small lithium battery cell. Its nominal voltage is 3.7 volts. If you want to form 48 volts, according to the principle of circuit voltage, if you want to pressurize, you must use a series connection. 48u0026pide;3.7u003d12.97, the integer is 13. Therefore, as long as 13 18650 cells are connected in series, a battery pack of about 48 volts can be realized, 13*3.7u003d48.1 volts. Of course, this voltage range is not really fixed at 48 volts, but an approximate value. The lowest discharge voltage is 2.75*13u003d35.75 volts, and the highest charging voltage is 4.2*13u003d54.6 volts. Although the importance of the protection board is simply connected in series, it can increase the voltage like a stacked Arhat, but the lithium battery is too delicate and too dangerous. It cannot be over-discharged or over-charged, that is, the charging voltage cannot be too high, otherwise it may be possible. It will explode, and it must be discharged regardless of the cost, otherwise the battery will be broken, so we need something to protect from overcharging or overdischarging, this is the lithium battery protection board. The essence of the lithium battery protection board is to test the temperature, voltage and current of the lithium battery pack, so that these parameters are controlled within a certain range, so as to guard against extreme damage to the lithium battery and even cause safety problems, such as high voltage and need to be cut off Charging circuit; if the voltage is low, discharging of the circuit must be prohibited; if the current is too large, input or output must be prohibited. There are mature off-the-shelf protection boards on the market, just buy them straight and use them, connect them according to their drawings and use them in accordance with the requirements of the instructions. Just don't connect the wrong wires. Because the cost of the protection board is not cheap, there are very few people who use a protection board for each single 18650, often after multiple lithium battery cells are connected in parallel, as a unit to protect, in fact, it can only protect This unit after the parallel connection does not really protect each unit. The purpose of parallel connection is to increase the capacity of the battery pack. The single capacity of 18650 lithium batteries currently on the market is about 2500maH. If two are connected in parallel, it is 5000maH, and so on. The advantages of the combination of series and parallel connections. Generally, the internal resistance of 18650 single-cell lithium batteries is about 70 milliohms. If the battery is connected in series, the internal resistance will increase with the series connection. Parallel connection is just the opposite. The greater the internal resistance, the more heat will be generated. The lower the efficiency, the higher the temperature. If the temperature is higher than a certain value, the lithium battery will be damaged. The connection of the lithium battery is also a problem, because the battery shell is 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, the internal resistance of the battery pack will be added. It is easy to cause heat during frequent charging and discharging, which may cause unexpected safety accidents. The copper wire and copper strips for the connection between the batteries are also very important. The selection should be calculated based on the current. Of course, the thicker the better, it can also reduce the internal resistance between the battery packs. 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: Lithium battery working principle and analysis of charging and discharging requirements