Author：aliceDate：2024-2-29
With the development of battery technology, people have higher and higher requirements for the driving experience of electric vehicles. In the past, electric vehicles needed to be charged overnight, sometimes as little as 8 hours. In recent years, lithium battery fast charging technology has emerged, and many electric vehicles can already be charged in 15 minutes and have a battery life of 80%! But currently only lithium batteries can do that. So the question is, why can’t lead-acid batteries charge so fast? There are four main reasons!
First, the cost of fast charging is high
Lead-acid batteries themselves are only used by mid- to low-end models, while high-end electric vehicles use lithium batteries. To achieve fast charging of lead-acid batteries, ordinary chargers cannot do it, and a customized fast charger is required. The internal structure and components of the lead-acid battery itself also need to be upgraded, and the process needs to evolve. This will significantly increase the vehicle's factory cost.
Currently, the graphene lead-acid battery that supports fast charging supports 2 hours of fast charging. Both its positive and negative electrodes use graphene material, which reduces resistance, reduces battery heating, and avoids excessive water loss in the battery. However, it is difficult to fully charge a lead-acid battery within 30 minutes with current technology.
Second, battery life will be shortened
The general cycle number of lead-acid batteries is about 500 times, and even graphene batteries only have about 800 times. Once fast charging is used, the high current will accelerate the cycle loss of the battery. In severe cases, battery bulging and plate vulcanization may occur. In this case, even if safe fast charging is used, the battery will become hot and hot, which will accelerate the increase of moisture inside, eventually causing the battery to lose water.
Third, there is no need to use fast charging for lead-acid batteries.
If it is a household electric vehicle, it is basically used to ride to work during the day, and the commuting distance is within 10 kilometers. The current 48V20ah battery can run 40-50 kilometers when fully charged. The power is basically enough! Don’t worry if you slowly charge it at home at night. You can use it normally the next day. Unless you are running a takeaway, you may consider using fast charging only if you want to run a few more orders. However, with the emergence of battery swapping cabinets, delivery boys no longer need to fast charge, and basically swap batteries directly. There is basically no market for fast charging of small-capacity lead-acid batteries!
Fourth, fast charging has certain safety risks
Although lead-acid batteries will not explode, in the case of fast charging, the battery and charger are under high current conditions, which will cause the equipment to become hot. If the components inside the charger are burned out, , there is also the possibility of fire. Especially when using fast charging in the middle of the night, there is a certain risk of fire.
Summarize:
From the perspective of chemical properties, the energy density of lead-acid batteries is not high, and the resistance is relatively larger than that of lithium-ion batteries. The principle of fast charging is to allow the battery to absorb a large amount of electric energy in a short period of time. If the capacity is not large enough, It's easy to "suffocate". Relatively speaking, lithium batteries have more active chemical properties, higher energy density, smaller resistance, and can quickly accept a large number of electrons when charged quickly. Therefore, in terms of fast charging performance, lithium batteries are better than lead-acid batteries!
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