Is LiFePO4 cell balancing important? The answer is absolutely YES! Successful battery balancing will greatly affect the subsequent performance of the entire battery pack.
Most of people may not understand what Lifepo4 battery pack balance is. In simple terms, it is the process of balancing the voltage and charge of each cell in a battery pack. Since the power of a single battery cell is usually not enough to meet our needs, we usually assemble a pack of batteries together as a whole power source. Ideally, these batteries would be brand new, with the same voltage, capacity, etc. When each cell leaves the factory, there will be more or less factor to effect the charge in part. And there are many influencing factors during battery transportation. This can lead to some degree of variation even with new batteries that becomes more and more noticeable during cycling, and in order for these batteries to function as a complete battery and work better together, we have to perform lifepo4 battery balance. As a simple example, lifepo4 batteries with relatively small capacity will charge faster when charging, and if assembled in the same group of batteries, they will limit further charging of other batteries with relatively large capacity. In other words, the same battery with a relatively small capacity will also discharge faster than other batteries, thereby limiting the discharge capacity of the entire battery pack. In addition, the cut-off voltage of a high voltage battery is different from that of a low voltage battery, which means that there will be excess performance. Therefore, we have a theory that can be generalized - the bucket effect, where the weakest cell will determine the capacity of the whole battery pack, and the strongest cell will determine the cut-off voltage of the whole battery pack. In this case, in addition to the limitation of the battery pack performance, there are also relatively more safety issues, such as overcharging and overdischarging, which can cause permanent damage to the same battery pack which can cause permanent damage to all cells in the same battery pack. Therefore, the balance of LiFePO4 batteries is necessary for the better use of the batter.
How to do LiFePO4 Battery Balancing?
First of all, we need to know that there are two most traditional methods of battery balancing, namely top cell balancing and bottom cell balancing. However, as technology continues to advance, we prefer to use scientific means to solve these complex problems. Currently, most people use a device called a balancer. This equipment can effectively complete the balancing of lifepo4 batteries, which is more accurate and efficient than manual balancing. However, if there are no conditions, only manual balancing can be performed. Top battery cell balancing refers to the need to fully charge all the battery cells and then connect them into a battery pack for balancing, which is suitable for optimized charging. Bottom battery cell balancing means that all battery cells need to be discharged to the minimum required for safety, and then they are connected to form a battery pack for balancing. If you want to optimize discharge, this means that bottom balancing is the best balancing method for you. In short, the choice between top or bottom balancing depends largely on how the LiFePO4 battery pack is used. The core point is “balancing”.
In fact, manual balancing is not difficult. First, we need a multimeter: it is used to test the voltage of each battery cell. Then you need to record the voltage parameters of all the battery cells, and then arrange the battery cells in the order from smallest to largest. Of course, you can also go from big to small, if you like! Then, we need to choose a parallel connection to connect all the battery cells, why parallel? Because series connection is relatively unsafe for cell balancing, and parallel connection method is more suitable for cell balancing. After the connection is done, we need to wait for a long period of time, during which the cells with relatively high voltage will slowly inject charge into the cells with relatively low voltage, and eventually balance.
Also, don't forget to test the voltage and capacity of the battery pack with a multimeter to see if it matches your theoretical calculations.
