When new cars come on the market, of course I'm talking about electric cars, there's often an introduction like this: "quick charge, 80% charge in half an hour, range of 200km, completely solve your range anxiety!" Quick charging, used by commercial vehicles to improve equipment efficiency, and used by passenger vehicles to solve range anxiety, are approaching the "fill a tank" time. Has become the standard trend. Car 18650 battery supplier to share with you : lithium ion quick charge.
Our basic demands for charging:
1) charge quickly;
2) do not affect the life of my cell;
3) try to save as much money as possible. Try to charge as much power as possible into my battery.
So how soon can you call quick charge?There is no standard literature to give specific value, let's refer to the value threshold mentioned in the most well-known subsidy policy for a moment. As you can see, the entry level for quick charge is 3C.In fact, the requirement for quick charging is not mentioned in the subsidy standard for passenger cars.From the publicity materials of general passenger cars, it can be seen that it is generally believed that 80% of the 30-minute charge can be used as the stunt of quick charge to promote, so it is assumed that the 1.6c of passenger cars can be the reference value of entry-level quick charge.According to this thinking, the 15-minute propaganda is filled with 80%, equivalent to 3.2c.
Cylindrical rechargeable electric vehicle li-ion battery, there is an optimal charging current. In the context of fast charging, the parties concerned are divided into physical entities, including batteries, rechargeable units, and distribution facilities.
Let's talk about quick charging, just thinking about the battery.In fact, before there's a problem with the battery, there's a problem with the charger, with the distribution line.We mentioned the tesla charging pile, called the super charging pile, which has a power of 120kW.According to the parameters of tesla ModelS85D, 96s75p, 232.5ah and the highest 403V, the maximum power demand corresponding to its 1.6c is 149.9kw.From here, it can be seen that the charging pile has been tested by 1.6c, or 80% charging in 30 minutes, for the long-endurance pure electric vehicle.
In national standards, it is not allowed to set up charging stations directly in the original residential electricity network. The power consumption of one fast-charging pile has exceeded the electricity consumption of dozens of households. Therefore, charging stations need to be provided with 10kV transformers separately, and not all of the power distribution network in a region has more margin to add more 10kV substations.
Then talk about the battery. Whether the battery can bear the charging requirements of 1.6C or 3.2C can be viewed from both macro and micro perspectives.
Macro charging theory: The reason why this section is called "macro fast charge theory" is because the material that determines the fast charge capacity of a battery is the positive and negative electrode materials, microstructure, electrolyte components, additives, separator properties, etc. At the micro level, we temporarily set aside and stood outside the battery to see how li-ion rechargeable cylindrical batteries can be quickly recharged.
Optimal charging current for lithium batteries
In 1972, the American scientist JAMas proposed that the battery has the best charging curve and his Mas's three laws during the charging process. It should be noted that this theory is proposed for lead-acid batteries, which defines the boundary conditions for the maximum acceptable charging current It is the generation of a small amount of side reaction gas, obviously this condition is related to the specific reaction type.
However, the idea that the system has an optimal solution is universal. Specific to lithium batteries, the boundary conditions that define their maximum acceptable current can be redefined. Based on the conclusions of some research literatures, its optimal value is still a curve trend similar to Mars's Law.
It is worth noting that the boundary conditions of the maximum acceptable charging current of lithium batteries, in addition to the factors of lithium battery cells, need to consider system-level factors, such as different heat dissipation capabilities, the maximum acceptable charging current of the system is different .