Lithium iron phosphate battery for electric vehicle
The number of charge and discharge cycles of 18650 ternary lithium battery is about 800 times. Before purchasing a lithium battery, check whether the cells used are of quality. A. The quality of the battery core determines the quality of the battery, such as capacity and energy density. Second, find a lithium battery produced by a major manufacturer. The production process is mature and after-sales service is guaranteed. The market price of lithium batteries is 1,250 yuan/KW.H. If you have to travel a long distance, it is best to install a range extender. With it, you won't be afraid of running out of energy halfway and it can help you travel worry-free.
What is the normal internal resistance of an 18650 lithium battery?
First, you need to find a way to connect all these batteries togetherparallel, then find a 4.2V charger to fully charge all batteries. After making sure all batteries are charged to 4.2. V, separate them and let them rest. Wait a day or two, then find a multimeter to measure their voltage. Since these are used batteries, your requirements cannot be too high, so you can select those with voltage. is still above 4.1V after two days of rest, and see how many there are. If there aren't enough, take a few that are close to 4.1V and make them a multiple of 13 strings. It will be better if the batteries voltage is 4.1 or more. Either way, just increase it to a multiple of 13. A few times is enough. You can make multiple parallel connections ~ So don't you have an internal resistance meter? the internal resistance of these batteries one by one. Find a pen and write it on the battery, after avOnce you have it all written down, roughly divide it into 13 parts. Try to make the total internal resistance of each part of the battery equal ~, then you can. connect these 13 pieces in parallel, then connect them in series to form a 13 string battery, then connect your 13 string protection board and charge it. Inlet and outlet ports, then pack them to be waterproof and shockproof. absorbent, then get a case and install it, and you can put it in the car and use it. It's a waste of more than 300 yuan to buy an internal resistance meter. You should buy a discharge meter, which has better capacity. of 18650. The tester costs less than 50 yuan. If you have a 18650 with around 2.5AH, your discharge parameters can be set as follows: discharge current 2A, cut-off voltage 2.8V. Measure those with the lowest voltage after being. left for two daysrs, then voltage Measure the average and highest separately and compare the capacities. If the difference is big, eliminate the smaller ones. If the difference isn't big, keep them all. , you need to find a spot welder. You can buy it for more than a hundred yuan, and it is more convenient than an internal resistance meter. . .
The internal resistance level of 18650 lithium batteries varies depending on the type and use. For 18650 type batteries, such as Samsung 18650-2200-5C, since they are designed for high discharge current, their internal resistance is generally less than 35 milliohms, which shows a lower resistance value, which is more conducive to efficient energy production. In comparison, the internal resistance of ordinary 18650 batteries, such as standard Samsung models, is generally less than 80 milliohms. In real production, it can even belower, about 65 milliohms, which indicates that the normal range of internal resistance is 1.1 milliohms. what follows.
It should be noted that there are many types of 18650 batteries, including lithium-ion batteries and lithium iron phosphate batteries. The rated voltage of the lithium-ion battery is 3.7V, the charging cut-off voltage is 4.2V, the common capacity is 1200mAh-3000mAh, and the common capacity is 2200 mAh and 2600 mAh. The rated voltage of the lithium iron phosphate battery is 3.2V, and the charging cutoff voltage is 3.6V. Although the internal resistance may be slightly higher, its characteristics are suitable for different application scenarios .
In short, if you are looking for high efficiency and performance, the internal resistance of 18650 power type is less than 1.1 milliohms, which can be regarded as normal, while the ordinary model is generallynt less than 65 milliohms. Understanding the internal resistance of a battery is essential for evaluating its performance and selecting the appropriate application.