Classification and Maintenance Of Electric Bicycle Batteries
August 20, 2020
Introduction to the classification and maintenance of electric bicycle batteries
Due to the vigorous promotion of new energy vehicles and electric vehicles, power batteries have also become popular. Power batteries are power products that provide power sources for new energy vehicles and electric vehicles. At present, power batteries are mainly divided into the following three categories:
1. The lowest level: lead-acid batteries have an energy density of 0.03~0.05 degrees/kg, which is too low and has heavy pollution. It can only be used in current battery bicycles. It is also a power source that will be phased out by the country in the future.
2. High-end: lithium iron phosphate battery, 0.4~0.5 degrees/kg, the price is more expensive, 2000~3000 cycles life, electric vehicles can already achieve a single charge to travel 80-100km, or even higher, is the current electric vehicles and electric bicycles The development trend of battery.
3. Ultra-high-end: Super capacitor power battery, 1.0~1.5 degrees/kg, cheap, maintenance-free, 100,000 to 500,000 charge and discharge cycle life, will become the mainstream of power batteries in the future.
Lead-acid batteries have been in development for a long time. Due to their low energy density and serious pollution, they will be phased out in the future. Supercapacitor batteries are currently rarely used in electric bicycles. So the editor mainly talks about the maintenance of lithium batteries.
To do a good job in the maintenance of lithium batteries, it is necessary to know how general electric bicycle lithium-ion batteries fail:
1. Short circuit of positive and negative poles inside the battery:
The internal short circuit of the battery is caused by the inside of the battery cell. There are many reasons for the internal short circuit of the battery, which may be caused by defects in the production process of the battery cell or the deformation of the battery cell due to long-term vibration and external force. Once a serious internal short circuit occurs, the control cannot be prevented, and the external insurance does not work, and smoke or burning will definitely occur. If we encounter this situation, all we can do is to escape as soon as possible.
2. Battery cell leakage:
This is very dangerous and a very common failure mode. Many accidents of electric self-ignition are caused by battery leakage. There are reasons for battery leakage: external force damage; collisions, improper installation and damage to the sealing structure; manufacturing reasons: welding defects, insufficient sealing glue, and poor sealing performance.
3. Lithium precipitation in battery negative electrode:
Improper use of the battery, overcharging, low-temperature charging, and high-current charging will cause the battery's negative electrode to degrade lithium. Lithium iron phosphate or ternary batteries produced by most domestic manufacturers will undergo lithium evolution when charging below 0 degrees Celsius. Above 0 degrees Celsius, they can only be charged with low current according to the characteristics of the battery. After lithium precipitation in the negative electrode occurs, the lithium metal cannot be reduced, resulting in irreversible degradation of battery capacity. Lithium evolution reaches a certain degree of severity, forming lithium dendrites, piercing the diaphragm and causing an internal short circuit. Therefore, the power battery should not be charged at low temperature when in use.
4. Bloating and swelling of batteries:
There are many reasons for flatulence, mainly due to side reactions inside the battery to produce gas, the most typical side reaction with water. The problem of flatulence can be avoided by strictly controlling the moisture in the cell production process. Once battery bloating occurs, liquid leakage will occur.
Knowing how the above lithium batteries fail, we must do a good job in the maintenance of the lithium battery of the electric bicycle, especially in the summer, we must do a good job of maintenance to extend the service life of the electric bicycle.
1. When the electric vehicle is on the bridge, climbing or driving against the wind, it should be driven by manpower to prevent the battery supply current from increasing suddenly;
2. When you just get on the bike or when you want to ride after the emergency brake is stopped, it is best to pedal a few times and wait for the electric bike to reach a certain speed before you ride it. Try not to use electric power to start the electric vehicle when it is stationary;
3. During riding, if you need to accelerate, you should slowly rotate the speed control handle to avoid direct acceleration to the fastest gear. Not only will it not immediately increase the speed of the car, but it will also produce an inrush current that will damage the battery. When the road conditions permit, make the electric vehicle drive at the highest speed as far as possible;
4. During riding, try to avoid frequent braking and starting, and use pedals when the road is crowded. This not only increases the "continuation mileage" and improves the battery efficiency, but also extends the battery life;
5. Charge frequently so that the battery is always fully charged. If possible, charge it as you use it, but you must grasp the total amount of charging time;
6. The electric vehicle must be fully charged for more than 12 hours before using the electric vehicle for the first time. Normally, it is sufficient to charge it for 2-3 hours when the battery is relatively sufficient. If the battery is low, it will be 6-7 hours. If the battery is not to be used for a long time, store the battery after it is fully charged and recharge it regularly;
7. The battery level shows that the battery is dead. After a period of time, it is found that the battery has a small amount of voltage, which is called "rebound voltage". Do not use this "rebound voltage" to drive.
8. The charger must be used for charging. Each electric bicycle has different battery specifications and specific attributes. For different electric bicycles, the charger configuration will be different. Mixed use is likely to cause overheating. The phenomenon is not conducive to the durability of the battery!
Proper use of lithium batteries for electric bicycles is generally not a problem for about 2-3 years. On the contrary, the service life is greatly shortened, and the battery has to be replaced after