Electric vehicle battery maintenance knowledge questions and answers

The precautions for using batteries are as follows:

1. Do not replace the charger casually and do not remove the speed limit of the controller.

Chargers from various manufacturers generally have personalized requirements. Do not change chargers at will when you are not sure. If the mileage requirement is relatively long and multiple chargers must be equipped for charging in different places, use the additional charger for charging during the day and the original charger at night. Although removing the speed limit of the controller can increase the speed of some cars, it will not only reduce the safety of the car, but also reduce the service life of the battery.

2. Protect the charger.

Generally, there are instructions on protecting the charger in the instruction manual. Many users do not have the habit of reading the instruction manual. They often remember to look for the instruction manual after the problem occurs, which is often too late. Therefore, it is very necessary to read the instruction manual first. In order to reduce costs, current chargers are basically not designed to be highly resistant to vibration. Therefore, chargers should generally not be placed in the trunk and basket of electric bicycles. In special cases, if it is necessary to move, the charger should also be wrapped with foam plastic to prevent vibration and bumps. After many chargers are vibrated, the internal potentiometer will drift, causing the entire parameter to drift, resulting in abnormal charging status. Another thing to note is that the charger should be kept ventilated during charging, otherwise it will not only affect the life of the charger, but also thermal drift may occur and affect the charging status. This will damage the battery. Therefore, it is also very important to protect the charger.

3. Charge every day.

Even if you don't need a long battery life and can use it for 2 to 3 days after charging once, it is still recommended that you charge it every day, so that the battery is in a shallow cycle state and the battery life will be extended. Some early mobile phone users thought that it is best to charge the battery after it is basically used up. This view is wrong. The memory effect of lead-acid batteries is not that strong. Frequent discharge has a greater impact on the life of the battery. Most chargers may have a battery charge of 97% to 99% after the indicator light turns to indicate that it is fully charged. Although the impact of only 1% to 3% undercharging on the battery life can be almost ignored, it will also cause undercharging accumulation. Therefore, it is best to continue floating charging after the battery is fully charged and the indicator light turns on, which is also good for inhibiting battery sulfation.

4. Charge in time.

The battery begins to sulfide after discharge, and obvious sulfide appears after 12 hours. Timely charging can remove minor sulfide. If not charged in time, these sulfide crystals will accumulate and gradually form coarse crystals. General chargers are powerless against these coarse crystals, which will gradually cause the battery capacity to decrease and shorten the battery life. Therefore, in addition to charging every day, you should also pay attention to charging as soon as possible after use to keep the battery in a full state as much as possible.

5. Perform deep discharge regularly.

Regular deep discharge of the battery is also beneficial to "activate" the battery and slightly increase the battery capacity. The general method is to fully discharge the battery regularly. The method of full discharge is to ride the bike under normal load conditions on a flat road until the first undervoltage protection. Note that we especially emphasize the first undervoltage protection. After the first undervoltage protection, the battery voltage will rise after a period of time and return to the non-undervoltage state. If the battery is used again at this time, it will cause great damage to the battery. After the full discharge is completed, fully charge the battery. You will feel that the battery capacity has increased.

6. Develop some good habits to save electricity.

Use coasting as much as possible. When going downhill, use the power-off coasting method to slow down as much as possible. When you are about to encounter a traffic light, start coasting in advance to minimize braking. A friend told me that he would rather make one more turn than brake once, which makes sense. When starting, it is best to add riding assistance, which not only increases the starting speed, but also reduces the loss of battery power and life damage.

7. Pay attention to the charging environment.

The best ambient temperature for charging is 25℃. Most chargers now do not have an automatic control system that adapts to the ambient temperature, so most chargers are designed based on an ambient temperature of 25℃, so it is better to charge at 25℃. Otherwise, it is inevitable that there will be problems such as undercharging in winter and overcharging in summer. The ambient temperature is rarely at 25℃, so there will inevitably be problems such as overcharging in summer and undercharging in winter. Fortunately, most families now have the conditions for indoor temperature control, so when charging, it is best to arrange the battery and charger in a ventilated and temperature-controlled environment.

It is especially important to note that when the battery is in a low temperature outdoor state in the north winter and then enters a warm room, frost and condensation will appear on the surface of the battery. In order to avoid battery leakage caused by frost and condensation, the battery should be charged after the temperature rises to close to the indoor temperature and is dry.

8. Make full use of maintenance conditions

Many electric bicycle dealers can provide battery inspection and maintenance services, and these services should be fully utilized. Some brands of electric bicycles require battery inspection and maintenance. For example, regular inspection and maintenance of the battery can reduce damage to the battery. Repairing the battery's state of charge can alleviate the failure of "battery lag", which is easy for dealers equipped with maintenance capabilities. For water loss, replenishing water when the battery capacity is 70% is better than replenishing water when the battery capacity is 40%. Some brands of products even propose that not inspecting the battery within the specified time is equivalent to giving up the battery warranty period. Consumers suffer losses that should not have occurred. Therefore, consumers should make full use of the conditions for battery inspection and maintenance to extend the battery life.

Through these methods, users can greatly extend the service life of the battery. Some users have a shorter driving range, and the battery life is relatively long, and some problems are relatively difficult to find. Therefore, the "deep discharge" measure mentioned in Article 4 is also an effective way to find battery problems in time, and don't wait until the battery problem becomes serious and difficult to deal with.

A distributor in Wuxi asked: What is the working principle of lead-acid batteries?

Answer: Lead-acid battery is the most widely used battery. It uses sponge-like lead as the negative electrode and lead dioxide as the positive electrode. We call these two substances active substances. Sulfuric acid aqueous solution is used as the electrolyte, and they jointly participate in the electrochemical reaction of the battery.

The chemical reaction principle of lead-acid battery is as follows

Negative electrode reaction: Pb+HSO4- PbSO4+H++2e

Positive electrode reaction: PbO2+2e+HSO4-+3H+ PbSO4+2H2O

Electrode reaction: PbO 2 +2 H+ +2HSO 4- +Pb 2Pb 2 SO 4 +2 H 2 O

Charging state Discharging state

From the above reaction principle, we can see that during discharge, both the positive and negative electrode materials react with the sulfuric acid in the electrolyte to generate lead sulfate, so it is called "double sulfation reaction". Under normal circumstances, the generated lead sulfate has a loose structure, and its crystals are very small, and the electrochemical activity is very high. This highly active lead sulfate can regenerate lead dioxide at the positive electrode and spongy lead at the negative electrode under the action of current during charging . Through this stable reversible process, the battery achieves the function of storing and releasing electrical energy.

An electric car user in Shanxi asked: How can users use the battery to extend its service life?

Answer: Experienced users know that battery cost is the biggest consumption of electric bicycles, so users are very concerned about extending the battery life. First of all, it is assumed that there is no problem with the charger. Whether the user uses it correctly is crucial to the battery life.

Mr. Li from Nanjing asked: What are the causes and hazards of sulfation of lead-acid batteries?

Answer: Lead sulfate is highly active for a period of time after it is formed. If it is not charged in time or charged incompletely during this period, it will not be converted into positive and negative active substances in time. The lead sulfate will recrystallize at low temperatures and precipitate on the crystalline lead sulfate. This will be repeated again and again, causing the crystal particles to grow continuously, becoming lead sulfate crystals with poor conductivity, difficult to dissolve, and difficult to recover when charged, which is commonly known as irreversible sulfation (the salification referred to in this manual refers to this type of salification). There are many reasons for battery failure, such as fatal electrode grid corrosion, severe deformation of the electrode grid, shedding of electrode active substances, internal short circuit or open circuit of the battery, and other physical and chemical reasons. However, statistics show that the failure of most batteries is caused by irreversible sulfation of electrode active substances.

This salt is difficult to recover to lead dioxide and spongy lead during charging, which is very harmful to the battery:

★ Its formation consumes active substances, reducing the effective capacity of the battery. If this continues for a long time, the battery will be scrapped.

★Not only is it difficult to recover during charging, but it will also block the gaps in the porous electrode, hindering the passage of electrolyte and increasing internal resistance;

★More heat is generated during charging and discharging. The higher the battery temperature, the greater the corrosion and deformation of the plate, causing the active material to fall off and leading to the structural failure of the battery;

★Reduce charging efficiency, prolong charging time, and waste time and energy;

★It leads to more serious electrolysis of water, and the battery is prone to water loss and drying up;

★Due to the decrease in capacity and insufficient output power, the only way to maintain a certain output is to increase the depth of discharge, which will cause more serious sulfation and form a vicious cycle;

★Due to the consumption of sulfuric acid, the electrolyte density decreases, the large current discharge capacity decreases, and the performance decreases.

The main reasons for irreversible sulfation during battery use include:

◆Frequent deep discharge and over-discharge, no timely charging or insufficient charging;

◆The electrolyte density is too high;

◆Changes in battery ambient temperature;

◆Batteries will become depleted if they are left unused for a long time in a low-power state;

◆Battery performance in the battery pack is inconsistent, and there are lagging batteries with large differences; the performance is that the capacity of a certain battery in the battery pack is significantly lower than that of other batteries, causing the voltage of the entire battery pack to drop. When charging, the lagging battery is overcharged because it is fully charged first while the other batteries still need to be charged. When discharging, the lagging battery is emptied first, resulting in overdischarge, which further aggravates sulfation and makes the lagging degree more serious, forming a vicious cycle.