What are the hazards of lithium battery pressure difference?
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Update time : 2021-09-11 11:36:19
There are many kinds of lithium batteries, such as ternary lithium, lithium manganese, lithium iron phosphate batteries, etc. by the raw material system; the volume, rate, and high rate of the rechargeable battery utilization area; the high temperature resistant lithium electronics planned by the application area , Low-temperature-resistant lithium battery; steel shell, polymer, square, 18650, 26650, etc. divided by the exterior, the variety is complete, here is no way to illustrate one by one, let us talk about the harm caused by the pressure difference of the lithium battery ?
Today, the key to lithium batteries used in electric vehicles are ternary lithium batteries and lithium iron phosphate rechargeable batteries, 18650 cylindrical and polymer hard packs, but 18650 cylindrical ternary lithium is popular. The working voltage area of the ternary lithium battery is the nominal voltage, and the lithium battery is based on the working voltage volume regulation during the application, and several batteries are connected in series and composed.
For example, if a 2Ah capacity rechargeable battery must be assembled into a 36V/10A lithium battery pack, then five must be connected in that case, and then 10 in series, a total of 50 18650 must be used; the lithium battery is afraid of overcharging and overdischarging. Therefore, the lithium battery pack and the external power circuit should be based on a maintenance power circuit to limit the upper and lower working voltage of the rechargeable battery.
The uniformity of a variety of lithium battery packs and lithium battery packs is very high. The volume, internal resistance, and charging and discharging service platform of a group of 18650 lithium battery packs all need the same; but when you go home, you can’t find two in the world. The lithium battery packs are exactly the same, so it must be impossible to make the same lithium battery packs. Certain differences are allowed. However, the specifications of each lithium battery pack are different, so the quality also has the problem of uneven quality. .
What harm does the pressure difference of the lithium battery have? For example, for a 36V battery, for various reasons, one of the series of rechargeable batteries has already achieved the maintenance value when the battery is charged, and the battery charging function of the lithium battery protection board may be turned off, even if the other rechargeable batteries are The working voltage is still unable to carry out volume filling.
When charging and discharging, the low volume will first maintain the lower limit value of the working voltage, even if the rechargeable battery has a volume that has not been charged and discharged, the lithium battery protection board will also turn off the charge and discharge function, which is a white short board effect! This should let everyone know that the pressure difference will cause the overall efficiency of the lithium battery pack to be fully utilized. The key is reflected in the shortened schedule, cycling power, and insufficient battery charging.