Electric vehicle battery safety issues

Electric vehicle battery safety issues

With increase of temperature, more and more people use electric vehicles for transport. The safety of electric vehicle batteries is getting more and more attention by consumers.

According to the type of battery, the electric vehicles currently on the market mainly divided into lead-acid battery models and lithium-ion models. Regardless of the type of battery, pay attention to safe operation from the time of purchase to use.

The technical maturity and performance of lead-acid and lithium-ion batteries are quite different. Lead-acid battery technology has been in existence for hundreds of years. Due to its high stability and high application of lead elements, lithium-ion batteries have also used. The development technology of more than 30 years is relatively mature, but due to the active performance of lithium, the application range is relatively small. The difference in performance between the two types of batteries is mainly in the following aspects:

1. Environmental protection. Lithium battery is not polluted (not absolute), and lead acid battery has heavy metal pollution on the side of improper recovery

2. Then the energy. The mass ratio and volume ratio of lithium batteries are about 40% higher than that of lead-acid batteries.

3. Price. Lithium batteries of the same capacity are more than double the price of lead-acid batteries.

4. The service life. At present, the general-purpose lithium iron phosphate charged 1500 times, and has no memory effect. After charging 1500 times, about 85% of the storage capacity, while the lead-acid battery is about 500 times and the memory effect is obvious.

5. Self-discharge rate. Lithium battery monthly self-discharge is less than 3%, lead-acid battery is 15% to 30%, the difference is obvious.

6. Discharge characteristics. Simply speaking, a battery of the same capacity, in the case of a large current discharge, a lithium battery emits about 30% more electricity than a lead-acid battery.

7. Voltage platform of Lithium battery greater than 3V, lead acid battery is 2V

Here you should especially reminded of the safety of the two types of batteries. Power lithium batteries (lithium manganate, lithium iron phosphate) materials have different safety, lead acid battery technology is quite mature, and overall safety is higher than lithium batteries.

Line stealing and disaster

Since the lead-acid battery is higher in safety performance than the lithium battery, is the probability that the lithium-ion battery will burn more than the lead-acid battery? This is not the case.

The safety problem of electric vehicle batteries often appears in the charging process of electric vehicles, which not related to the performance of the battery itself.

When the electric vehicle is charging, the battery itself is not prone to short circuit and rarely explodes or burns. The electric vehicle battery and the randomly equipped charger generally have protection devices. The lithium battery has a control circuit and a protection board. Once the current is too strong or a line occurs. Short circuit, the protection system will automatically cut off to prevent the electric vehicle from exploding or igniting due to short circuit.

The cause of the ignition of the lead-acid battery generally related to the aging of the connecting line, or the poor heat resistance of the manufacturer's cut-off line, and the lithium battery explodes or ignites. In addition to the problem of aging or heat resistance of the line, the internal protection system of the battery may malfunction.

In addition, if the consumer is not operating properly during use, the battery damaged, charging time is too long, etc., and it will increase the risk of battery short circuit.

The line connection is loose and easy to ride.

The electric vehicle should withstand relatively strong vibration during operation. The reliability of all connections should evaluated. The connector should be equipped with a "self-locking" function to prevent it from falling off during vibration and pulling. The connection to the battery lug of the electric vehicle should take. The connector soldered to it with solder, and the connector crimped to the connection. If the contact is not strong, the degree is light, and poor conduction will occur, causing the line contact part to heat up, the line loss is large; the output voltage is low, affecting the motor power, making the mileage reduced or unable to ride normally.

During the driving process or charging process, the contact is not strong, and an open circuit may occur. When the circuit is broken, a strong spark may generated, which may explode the explosive gas inside the battery of the electric vehicle, especially the electric vehicle battery that has just charged, because the battery is inside. There are many explosive gases, and the battery of the electric vehicle is enough. When the circuit is broken, the spark is strong and the possibility of explosion is quite large.

Lithium battery is not charged, but it is in good condition.

Whether it is a lead-acid battery or a lithium battery, try to prevent the charging time from being too long. Do not charge more than 8 hours at a time, and try not to have a violent collision or contact with a hot object. Especially for lithium-ion batteries, the charging method is too long or the method of completely charging and recharging each time is not correct.

Since the lithium battery does not have a memory effect, the amount of charge per charge does not affect the energy storage effect of the battery. On the other hand, if the charging time is too long, it will affect the consistency of the battery pack and affect the life. In addition, this reduction in life is unrecoverable, so pay special attention to not overfilling once; it recommended charging 80% is best.

The discharge situation is the same. When charging, there must be a little electricity in the battery. The electric car does not need to recharged, which also affects the battery life.

In addition, after the battery completely discharged, the consumer should immediately replenish the electricity to avoid charging in a low temperature environment. If the electric bicycle not used for a long time, it is necessary to remember to replenish the power at the right time. This not only can extend the battery life, but more importantly, it ensures the stability of the battery performance.

Electric vehicle safety guarantee begins at the time of purchase

To ensure the safety of the use of electric vehicles, consumers must pay attention when they purchase. At present, the protection systems of regular manufacturers are relatively complete, and the wiring materials and interfaces of various components are relatively regular. Consumers should not be cheap, and must choose a regular manufacturer or a well-known brand of electric vehicles.

In addition, in the process of using the consumer, attention should also paid to the standard operation of the electric vehicle and the battery to prevent overcharge and over discharge. After the electric vehicle battery is heated, it is necessary to take cooling measures, and the battery can charged only when the battery temperature of the electric vehicle returns to normal. The installation position of the electric vehicle battery should ensure good heat dissipation as much as possible. When it is overheated, stop charging, and check the charger and electric vehicle battery. When the electric vehicle battery has a shallow discharge depth or when the ambient temperature is high, the charging time should shortened. After the electric vehicle battery discharged to the termination voltage, the continued discharge called over discharge. Over-discharge can seriously damage the electric vehicle battery, which is extremely detrimental to the electrical performance and cycle life of the electric vehicle battery.

Consumers should not only consider by price, cruising range and other factors when purchasing an electric car, line materials and components is also very important. In addition, the battery must to ensure no short-circuit. We should very carefully during installation all tools should insulated. First, connect electrical appliances besides the battery then connect the electric vehicle battery and wiring after checking no short circuit. The specification should well insulated to prevent overlap from crushed and cracked. This way could make the electric car safer and longer.

The page contains the contents of the machine translation.