Lithium batteries in the group process, due to the lithium battery itself constitutes a slight difference between the material and the level of different groups of processes, will make lithium batteries in the use and placement process appears inconsistent performance of the phenomenon, which is lithium battery discrete phenomenon, The quantitative index describing this discrete phenomenon is the dispersion, which is obtained by the function of several parameters. The main factors that cause the change of the dispersion are: resistance, voltage, capacity, temperature and so on.
1, the battery resistance, especially the internal resistance of the inconsistency, making the individual battery charge and discharge process changes in voltage, resulting in dramatic changes in the entire battery pack; 2, the battery voltage is inconsistent, will affect the battery 3, due to the battery work in the heat and endothermic process, the battery temperature will continue to change, when the overheating, it will bring performance degradation and security risks, it turns out that in recent years, in recent years, the battery can reduce the energy consumption, The occurrence of electric vehicle operation and test fire fuse is because the over-temperature protection is not in place cause the battery fever, the battery type not only lithium manganese oxide, lithium iron phosphate battery is also the case; 4, the capacity is the most serious dispersion Factor, the capacity of the main differences caused by two aspects of the performance problems, one part of the battery will be in the overcharge and over discharge state, resulting in burning, explosion and other unsafe factors, and second, low-capacity single cell because the end of the work, affecting the whole The energy of other single cells in the battery pack can not be completely released, causing the battery pack to degrade the life of the entire battery pack.
In order to reduce the negative impact of lithium battery dispersion, the maximum meet the uniformity of the battery pack requirements, the need for the following production and use of the angle to improve.
1, the production process, lithium battery design to ensure that meet the requirements of large-scale mechanized production, looking for control of product quality process methods to ensure that the single cell in the material and internal structure of the uniformity.
2, the use of the first to optimize the sorting matching technology, making the lithium battery in the initial consistency to be satisfied; followed by weakening the internal temperature of the battery imbalance, so that the current density as uniform as possible to reduce the battery contact resistance connection The
3, test the battery surface temperature and flow rate, select a reasonable and scientific ventilation structure, so that the entire battery surface temperature uniformity, to ensure that the battery pack when using each battery in the same temperature environment.
Battery consistency is poor in the battery manufacturing process more difficult to grasp the process, the current control methods are not perfect, but to strengthen the understanding of lithium battery dispersion to improve the consistency of lithium batteries is necessary, but also do the basis of this matter The