Why does the battery overheat?

If battery overheating is caused by excessive discharge current, there may be the following reasons: 

（1） Overload and long-term heavy load operation; 

（2）The resistance of the car body itself, such as axle problems, bearing problems, braking problems and friction between wheels and frame, etc. 

（3） the slope is too steep; 

（4）the battery capacity is too small;

（5）motor problems; 

（6）transmission line problem. The small capacity of the battery is one of the reasons for overheating of the battery, so the capacity should be increased and the working current should be reduced.

1. What is the harm of battery heating?

No matter in use or during charging, the car battery is allowed to generate small heat, but it is not allowed to abnormal heat. If the abnormal fever is obvious, you can feel it by touching the battery container with your hand. Over-heating is very harmful to battery. At first, heat will evaporate the electrolyte water and gradually dry up, then cause the charging efficiency decreases, plates deform, internal resistance increases, oxidation of mechanical parts accelerates, plates or separators burn out, and finally the battery capacity decreases and the service life shortens.

2. What are the reasons for the battery discharging and heating?

(1) Causes of discharge heating: Small battery capacity and discharge current exceeding 0.5C for a long time may cause fast discharging. Here, it is emphasized that although the battery consumes a certain amount of electricity after short-distance driving, it has a recovery process after rest, and the electrochemical process of the plate continues, so the voltage will pick up somewhat, but it does not mean that the capacity will pick up; On the contrary, when driving for a long distance and no rest during the trip, the electrochemical action of the plate and the consumption of electric energy will be carried out at the same time. There will be three situations:

① When the rated voltage of the motor is low, the battery capacity is small, and the working current is too large, the voltage will drop sharply, and the capacity will soon be exhausted, which is the most unfavorable to the battery.

② The electrochemical reaction speed of the battery can only maintain driving, and the battery has no chance of recovery and rest, so it is often charged and discharged in the whole cycle, and it will be over-consumed if you are not careful. When going uphill in the wind, the power consumption is very high, forcing the battery plate to react sharply, and the heat of the battery container is high, which will damage the battery, shorten the service life, indicating that the capacity is not surplus.

③ Ideally, the electrochemical reaction speed of the battery can easily supply enough electric energy. If there is no abnormal heat on the container, indicating that the battery capacity is surplus.

Only the last one of the three situations is ideal for long-distance driving. It should be noted that if the battery container is obviously heating, the heat of the internal battery itself is even higher.

3. What are the reasons for the battery to heat up when charging?

In the process of charging the battery, part of the electric energy is converted into chemical energy, and the other part is converted into heat energy and other energy. Battery heating during charging is a normal phenomenon, but when the temperature is high, it is necessary to check whether the charging current is too large or whether there is a short circuit inside the battery, etc.

The heating value has little relation with the amount of electrolyte. If the internal resistance of sealed battery increases when the amount of electrolyte is small, it will also cause the battery to heat up and the terminal voltage will be high when charging. Aging batteries, dry electrolyte, internal short circuit, etc. can also cause to heat. The charger can't keep constant voltage at the later stage of charging, so that the battery voltage exceeds the allowable value and the temperature will rise, or it will swell in serious bulge, and the service life will end.

During use, try not to place it horizontally or upside down to prevent a large amount of gas generated inside the battery and cannot discharged smoothly from the vent valve. Especially when charging, otherwise the container may burst.