What should I pay attention to when the lithium battery and protective board choose?

　　Author ：Iflowpower – Portable Power Station Supplier

1: Lithium ion battery type and capacity selection. First, according to your motor power (to actually power, the general riding speed will correspond to a corresponding actual power) to calculate the battery to supply the continuation current. For example, the motor continues to current 20A (48V 1000W motor), then the battery can supply 20A current for a long time and low temperature rise (even 35 degrees in summer, the battery temperature is also preferably controlled below 50 degrees).

In addition, if the current is more than 20A current, the overpressure is doubled (96V, such as the ECPU 3 gear), continue to current to 50A. If you like to use it for a long time, then use the battery that can continue to supply 50A current (or pay attention to the temperature rise problem). The battery continuing current here is not a merchant nominal battery discharge capability.

Merchants nominal a few c (or dozens of people) are battery discharge capabilities, and it is really discharged under this current, and the battery is hot. If it is not long, the battery life will be short. (And our electric cars use the battery environment is the battery, the battery is discharged, basically do not leave the gap, the package is very strict, don't mention how to make a hot and cold).

Our use environment is very bad. Battery discharge current needs to use. Evaluation of battery discharge current is to see how much battery corresponding under this current is.

The only principle discussed here is actually the temperature rise of the battery during use (high temperature is lithium battery life). It is best to control the battery temperature below 50 degrees. (The best between 20-30 degrees).

This also means if it is a capacity-type lithium battery (controlled below 0.5C), the supply 20A continues to discharge current to capacity or more (of course, if you want to see the battery internal resistance). If it is a power-type lithium battery, it is normal according to 1C.

Even the A123 ultra-low internal resistance type lithium electricity, it is also best to discharge at 1C (not more than 2C is good, 2C discharge is actually only half an hour, no electricity, no big money). Capacity selection to see factors such as the size of the car, personal expenditure budget, expecting the size of the car activity. (Small capacity generally non-powerful lithium battery 2: screening of batteries Assembly series using lithium ion batteries is a serious imbalance of battery self-discharge.

As long as everyone is unbalanced, the problem is that this state is an urgent state. The good battery is very small. It is very bad for the battery.

The self-discharge is not small. The state is generally improved. State, this process is unstable.

Therefore, the self-discharged battery is screened, only the battery pack of the discharge is left (generally the self-discharge, the manufacturer is measured, the problem is a lot of unqualified products into the market). On the basis of self-discharge, select a similar structure similar. Even if the capacity is not similar, it will not affect the battery life, but it will affect the available capacity of the entire set of batteries, such as 15 capacity is 20ah, only 1 is 18ah, then the total capacity of this set can only be 18ah.

The last will be that this battery is dead. The protective board is protected, and the unit voltage is still high (because other 15 battery voltages are normal, there is electricity). Therefore, the discharge protection voltage of the entire set of batteries can see that the entire set battery capacity is consistent (provided that the whole battery is full of electricity).

In summary, the high and low capacity does not affect the battery life, just affects the capacity, so try to select a similar assembly. Assembly battery, ohmic contact resistance, good electrode. It is the smaller the wire and the electrode contact resistance, otherwise the contact resistance large electrode will heat, this heat will pass the electrode to the battery life inside the battery life.

Of course, the performance of the assembly resistance is the same as the battery pack pressure under the same discharge current. (Part of the pressure drop is the internal resistance, part of the assembled contact resistance and electric wire resistance).