Problems and maintenance of electric vehicle lithium batteries

　　Author ：Iflowpower – Portable Power Station Supplier

1 What is the problem of electric car battery? 1.1 Why is it caused by the battery itself! In the previous period, we understand the working principle of the lead-acid battery. The process of lead-acid battery charging is the process of electrochemical reactions.

When charging, the leads of sulfate form a lead-oxide, and the lead in the lead is reduced to the lead of sulfate. The lead of sulfate is a very easy crystallization. When the electrolytic solution of the electrolytic solution in the battery is too high or when the idle time is too long, it will "hug" group, form a small crystal, these small crystals are again attracted around Lead of sulfate, as the same as the snowball is the same as the snowball, the crystal is not refurbished into the lead, which can not be restored to the lead in the electrode plate, but also precipitate on the electrode plate, which is called vulcanization.

At this time, the battery capacity will gradually drop until it cannot be used. When the pile of sulfate is a large amount of a pile, it will also attract lead particles to form a lead branch. The lead branches between the positive and negative plates will cause battery short circuit.

If there is a slit surface or sealing the plastic shell, the lead crystals of the sulfate will be accumulated in these gaps, and the expansion tension is present, and ultimately make the plate fracture fall off or cracking, resulting in a battery unpleasant physical damage. Therefore, the important mechanism of failure and damage caused by lead-acid batteries is that the battery cannot prevent vulcanization. 1.

2 The cause of battery production is aimed at the particularity of the lead-acid battery for electric bicycles, and various methods have taken a variety of methods. The most typical way is as follows: 1 Number of new increases. Change the original design of 5 pieces of 6 pieces to 6 pieces of 7 pieces, 7 pieces of 8 tablets, or even 8 pieces.

Reduce the capacity of the battery capacity by thinning the thickness and the partition, the number of newly enhanced plates. 2 increase the specific gravity of the battery's sulfuric acid. It is generally between 1.

21 to 1.28, and the specific gravity of the electric bicycle's battery is generally around 1.36 ~ 1.

38, which can supply larger current to improve the initial capacity of the battery. 3 Dissivity and proportion of lead-proof lead in the positive electrode active substance. The newly increased lead of the newly increased electrochemical reaction substance participating in the discharge, and added a discharge time, and added battery capacity.

Through these measures, the initial capacity of the battery satisfies the capacity requirements of electric bicycles, especially the characteristics of large current discharge of the battery. However, the polar plate has increased, the capacity of sulfuric acid is reduced, and the heat of the battery leads to a large amount of water, and the battery's micro short circuit and the probability of the lead branch bridge have increased. Increase the proportion of sulfuric acid to increase the initial capacity of the battery, but the vulcanization is more serious.

One of the most basic principles of the sealing battery is that after the positive electrode is oxygen, the oxygen is directly to the negative plate, which is absorbed by the negative plate and is reduced to water. The parameter of the technical indicator of the assessment battery is called "sealed reaction efficiency", this phenomenon is called "oxygen" cycle". In this way, the battery's loss of water is rare, and "maintenance" is realized, it is exemption.

To this end, it is required to be larger than the positive electrode plate capacity, but also known as negative transition. The new positive electrode active substance is inevitable, the negative transition is reduced, and the oxygen circulation is deteriorated, and the loss of water is added, which will cause vulcanization. Although these measures increase the initial capacity of the battery, it will cause water and vulcanization, and loss of water and vulcanization will contribute to each other.

The final result is sacrificed the life of the battery. 4 There is also a pole assembly doubeller problem. It is easy to show that the soldering is a polar plate.

And each battery has a ticker, which is 15 solder joints. There are 6 single single, with 90 solder joints, and a set of batteries consists of 3 12V batteries, with 270 solder joints. If there is a solder spot, the single-handed capacity is lowered, and the single-handed formation is behind, causing the entire battery, the battery will form a serious imbalance, so that this set of batteries fails in advance.

Even if the solder is controlled in one thousandth, the average of the cells will have a group of batteries per 37 batteries, which is absolutely unable to allow. The battery of the lead calcium alloy sheet is precipitated when the calcium is precipitated when welding, so that many battery manufacturers prefer to use low hem alloy grid without using lead calcium alloy. The low-ruthenium alloy plate is lower, the battery is large, the water is relatively serious, and the battery is easier to vulcanize.

From the above we can see: Why is there a good battery, some of the battery growth will be longer under the same conditions of use. 1.3 The reason why the electric vehicle use environment itself is due to the battery, which is vulcanized during use, but the lead-acid battery in other fields has a longer life than the lead-acid battery used on the electric bicycle, because the electric bicycle Lead acid batteries have a work environment that is more likely to vulcanize.

1 Depth discharge The battery is only one-way discharge when ignition is ignited. The power generation will be automatically charged with the battery after ignition, and does not cause the battery depth discharge. The electric bicycle is impossible to charge when riding, often more than 60% depth discharge, deep discharge, the lead concentration of sulfate, vulcanization will be quite serious.

2 large current discharge electric vehicles 20 km cruise currents are generally 4A, which has been higher than the battery operating current in other fields, and oversized electric vehicles are greater. Battery manufacturers have been charged by 70%, and 60% of 2C discharge is 60%. After such a life test, there are many batteries that can reach the charging and discharge cycle of 350 times, but the actual effect is far from the effect.

This is because the high current work has added 50% discharge depth, and the battery will accelerate vulcanization. Therefore, the battery life of the electric motorcycle is shorter because the body of the electric motorcycle is too heavy, the motor is high, and the working current is more than 8A when cruising. Some even reached 10A.

3 The charge and discharge frequency is used in the backup power supply. It will only be discharged when the power is powered off. If you stop 8 times a year, you need to reach the life of 10 years, just use 80 cycles Charging life, and electric vehicles a year charge and discharge cycle more than 300 times more common.

Even some people may be charged a few times a day, the time is very short, and it is used without charging. 4 Short-term charging, due to electric bicycles is a vehicle, it can be charged, and it is necessary to charge 36 volts or 48 volts within 20 hours of 8 hours, which must increase the charging voltage (generally a single section 2.7 ~ 2.

9 volts). ) The vulcanization of the battery is aggravated . 5 When discharged, it cannot be charged as a vehicle.

The charging and discharge of the electric bicycle are completely separated. After discharging, it is difficult to charge in time, while a large amount of sulfate formed after the discharge, such as more than half an hour If the rechargeable reduction is the lead, it will vulcanize the crystallization. 1.

4 Electric bicycle production reasons for most vehicles have left a speed limit plug, some cars are simply dropped to the factory, which can attract customers with heavy vehicles, and reduce costs, such a car is driving at high speed. The current is very large, which will seriously reduce battery life. The lowest protection voltage of 12V lead-acid batteries is 10.

5V. If it is a 36V battery pack, the minimum retention voltage is 31.5V, and most of the controller used in most vehicle manufacturers is also 31.

5V. The surface is correct, however, when only 31.5V voltage left in the 36V battery pack, due to the poor capacity of the battery, there will be a battery voltage lower than 10.

5V, the battery is in an over-discharge state. At this time, the battery capacity of over-discharge decline sharply. At this time, the damage impact on the battery is not only the single battery, but it affects the life of the entire set of batteries.

In fact, it has been 27V after the battery voltage is below 32V, and the new renewal capacity is less than 2 kilometers, but the damage to the battery is very large. As long as such a situation is 10 times, the battery capacity will be less than 70% of the nominal capacity. In addition, some users have found that the battery is under under pressure.

After 10 minutes, the battery does not undervolt, and it is taken to travel, which is more destroyed, and most cars are not given to the user. At present, there are adjustable potentiometers inside the most controller, and this adjustable potentiometer vibration drift is more serious. In the price competition, in the face of users who have more attention to the outside of the car, there are very few products that use anti-vibration precision multi-zip potentiometers.

Such controllers have a vibration drift and is not surprising. 1.5 The reason for the charging equipment is widely circulated by the industry: the battery is not used, but is contrary.

In order to satisfy the short-term high-capacity charging of the electric bicycle battery, in three-stage constant voltage limit, it is necessary to increase the constant voltage to 2.47V ~ 2.49V.

In this way, it is great to exceed the battery positive electrode panel anterior oxygen voltage and negative electrode plate. Some of the products of charger manufacturers have improved constant pressure transfer floating in order to reduce the indication of charging time.