What should lithium-polymer batteries pay attention to in series?

When multiple lithium polymer batteries are connected in series, it should be noted that:

First, ensure that the voltage, capacity, internal resistance, and self-discharge of multiple lithium polymer batteries are consistent.

2, in series, the lithium polymer battery 1 negative pole is connected to the lithium polymer battery 2 positive pole, and the lithium polymer battery 2 negative pole is connected to the lithium polymer battery 3 positive pole, and so on.

3, Lithium-Polymer battery in series, the battery top seal must be well insulated, the battery steps need to be covered with EVA or insulation pad, the core can be fixed with double-sided glue.

Lithium polymer batteries can be soldered, spot soldered, or screwed in series. It can be judged by battery use, battery size, and equipment.

5, lithium-polymer batteries in series, each string needs to be welded lead wire connected to the protection plate, a good equilibrium flow treatment.

Lithium polymer batteries can not damage the core in series, the battery can not be connected, and can not short-circuit.

The above dianchizhidu answer is for reference, hoping to help you.

In lithium batteries, multiple lithium cells are connected in series to obtain the required operating voltage. If what is needed is higher capacity and more current, then the power lithium batteries should be connected in parallel. With the combination of series and parallel methods, Gaodianya's high-capacity standard can be achieved. For example, the battery of a 36V10AH electric vehicle is to parallel 50 2000 MAH 3.6V lithium-ion batteries so that the capacity can reach 10 AH; Then connect 10 sets of parallel batteries together; When connected in series, the battery voltage can reach 36 V or more.

This connection is called "10 strings of 5", which means: 10 sets of lithium batteries connected in parallel by 5 sections; The nominal voltage of a lithium-ion battery is 3.6 V. Using lithium-ion polymers and other types of lithium batteries, its rated voltage is generally 3.7 V. Another problem with the use of Gaodianya batteries is that it is possible to encounter the failure of a certain section of the battery pack. It's like a chain. The more batteries you put together, the more likely it is to happen. As long as there is a problem with a single battery, its voltage will decrease. At the end, a section of "disconnected" batteries may interrupt the transmission of current. It is also easy to replace "bad" batteries because old and new batteries do not match each other. In general, the capacity of new batteries is much higher than that of old batteries. As the working voltage drops, it reaches the critical point of discharge end faster than the normal battery, and its service time is also shortened rapidly. Once the device is cut off due to low voltage, the remaining cells that are still intact can not send out the stored power. At this time, the bad battery also presents a large internal resistance. If it is still loaded at this time, the output voltage of the entire battery chain will be greatly reduced. In a series of batteries, a poorly performing battery, like a plug blocking a water pipe, generates huge resistance and prevents current flow. Other cells will also short-circuit, which will reduce the terminal voltage to 3.6 V, or disconnect the battery chain and cut off the current. The performance of a battery pack depends on the performance of the worst cell in the battery pack.

In order to get more power in parallel, multiple batteries can be connected in parallel. In addition to the parallel use of batteries, the use of larger batteries is not suitable for all uses due to the limitations of the available batteries. In addition, large-sized batteries are not suitable for the shape specifications required for dedicated batteries. Most chemical batteries can be used in parallel, and lithium-ion batteries are most suitable for parallel use. For example, the battery voltage consisting of 5 cells in parallel is maintained at 3.6 V, while the current and operating time increase to 5 times. Compared with battery series, high impedance or "open circuit" batteries have less effect in battery parallel circuits. However, parallel batteries reduce load capacity and shorten operating time. It's like an engine running only three cylinders. The damage caused by circuit short circuits is even greater because batteries that fail in short circuits quickly deplete the power in other batteries, causing damage to the entire battery life.

When using the connection method of string parallel, it is flexible in design and can use the standard battery size to reach the required rated voltage and current. It should be noted that the total power does not change due to different connection methods of the battery. Power equals voltage multiplied current. For lithium-ion batteries, serial connection methods are common. One of the most commonly used batteries is the 18650 lithium battery. It has a protective circuit, the lithium battery protection plate. The lithium battery protection plate can monitor each cell connected in series. Therefore, its maximum actual voltage is 42V. This lithium battery protection circuit(ie, lithium protection plate) can also be used to monitor the state of each cell in series. When using the 18650 lithium battery in series, it must comply with the following basic requirements: the voltage must be consistent, the internal resistance difference should not exceed 5 mm, the capacity difference should not exceed 10 mm A, and the clean connection point of the battery must be maintained. There is a certain resistance at each connection point. If the connection point is not clean or the connection point is increased, the internal resistance may affect the performance of the entire battery pack. Do not mix lithium cells from different manufacturers. To select lithium cells with high performance consistency, basically use lithium batteries to make batteries according to the above standards. Basically, it is to the standard. .. Over! If you have anything to say, please add ... Thank you!

Using lithium-ion batteries in series and in parallel sounds simple, but it takes a few simple rules to avoid unnecessary problems.

Do not mix different brands of lithium batteries, different capacities or old and new lithium batteries together to use, select batteries with the same performance. Replace all batteries when the battery is running low. When lithium batteries are used in series, use the same type of battery. Pay attention to the polarity of the battery. If there is a polar reload of the battery, it will reduce the voltage of the entire battery instead of increasing the voltage.

If you mix different capacities or old and new lithium batteries together, leakage, zero voltage, etc. may occur. This is due to the fact that during the charging process, the difference in capacity causes some batteries to be overcharged when charging, some batteries are not fully charged, and batteries with high capacity during discharge are not discharged, while those with low capacity are overcharged. In such a vicious cycle, the battery is damaged by leakage or low(zero) voltage.

In general, lithium battery strings need to be paired in parallel. The standard for pairing: the voltage difference of lithium battery cores ≤ 10mV, the internal resistance difference of lithium battery cores ≤ 5mΩ, and the capacity difference of lithium battery cores ≤ 20mA.

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