With the development of battery technology and the continuous increase of battery life, trams have changed from the dilemma that they had to be replaced within a few years. The “legs” are longer, and there are many usage scenarios. Kilometers are not surprising. As the mileage increases, the author found that some car owners have anxiety about vehicle decay. Recently, the epidemic has repeated again. I stayed at home and had relatively free time. I would like to share some thoughts on the “decay” of the battery in the vernacular. I hope everyone can also become a new energy car owner who is good at observing, pondering, and understanding the car.
When the author’s BAIC EX3 is in the state of a new car, it shows 501km at full power. At the turn of spring and summer after running 62,600km, it only shows 495.8km at full power. For a car with 60,000 km, the battery must be attenuated. This display method is more scientific.
1. Types of “Attenuation”
1. Low temperature attenuation in winter (recoverable)
Affected by low temperature, battery activity decreases, battery performance decreases, andattenuation. This is caused by the chemical properties of the battery itself, not only for new energy vehicles, but also for batteries. A few years ago, there was a saying that when you used a certain mobile phone to make a call outdoors in winter, the battery of the mobile phone was obviously charged, but the mobile phone suddenly turned off automatically. When you brought it back to the room to warm up, the mobile phone was charged again. This is the reason. It should be noted that the “battery attenuation” caused by temperature is affected by temperature, and the battery performance can be restored. To put it bluntly, in summer, the battery life of the vehicle can be fully revived! In addition, let’s add another knowledge point: Generally speaking, the temperature for the best performance of the battery of the electric car is 25 ℃, that is to say, if the temperature is lower than this temperature, it will inevitably affect the battery life of the vehicle. The lower the temperature, the more attenuation.
2. Life decay (unrecoverable)
The long mileage of the vehicle or the high power consumption of the floor electric drive usually increases the number of battery cycles; or the fast charging and high current charging times are too many, resulting in excessive battery voltage difference and poor battery consistency, which will eventually affect the battery life over time.
The small program developed by the owner of BAIC can obtain the real-time data related to the vehicle, the number of battery cycles, the voltage difference, the voltage of the single cell and other key information by connecting to the vehicle WIFI. This is what the intelligence of new energy vehicles brings to us. Convenient.
Let’s talk about the number of battery cycles first. Generally, battery manufacturers will “bragging” their battery technology in product releases, and the number of cycles can reach more than a thousand times or even more. However, as a household electric car user, it is impossible to drive so many times. Concerned about manufacturers bragging. Assuming that a 500km car has to run 500,000 kilometers after 1,000 cycles, even if it is 50 % off, it will still have 250,000 kilometers, so don’t be too entangled.
The charging and discharging of high current is divided into two aspects: charging and discharging: the former is fast charging, and the latter is driving on the floor. In theory, it will definitely affect the accelerated decay of battery life, but the vehicle’s BMS (battery management system) will To protect the battery, the reliability of the manufacturer’s technology is critical.
2. Several Viewpoints of “Attenuation”
1. “Decay” happens every day
The battery life is the same as the life of a person. One day less, even if you don’t use the car, it will decay naturally, but the difference is whether the owner’s life is “healthy” or “wasting” himself. So don’t worry about how my car is attenuated and make yourself very anxious, and don’t believe the nonsense words that some car owners say, “My car has run XX thousand kilometers, and there is no attenuation at all!”, just like you hear someone say You are immortal and live forever, do you believe it? If you believe it yourself, you can only hide your ears and steal the bell.
2. The instrument display of the vehicle has different strategies
The author has driven 75,000 kilometers of 2017 Benben EV180 fully charged on January 31, 2022, and can still be charged to 187km (normal full charge in winter shows 185km-187km), which does not reflect vehicle attenuation at all, but this does not mean The vehicle is not attenuated.
Each manufacturer has its own display strategy, and products in different periods have different display trends. According to the author’s observation, the display strategy of car companies to “display” the attenuation through a fully charged display is on the Roewe ei5 in 2018 , while the display strategy of the models produced in 2017 and before is: no matter how many miles driven, fully charged Always that number. Therefore, I heard some car owners say, “My car has run XX thousand kilometers, and there is no attenuation at all!” Usually, they are owners of old models, such as BAIC EV series, Changan Benben, etc. The reason why all car companies later showed “attenuation” under full power was also because car company engineers found that “immortality” was not suitable for the law of development of things. Such a display method was unscientific and was abandoned.
3. The mileage reduced by the digital display of the fully charged meter ≠ the decayed mileage
After the vehicle is fully charged, the displayed number decreases and does not directly represent the decayed mileage. As mentioned above, decay occurs every day, and there are too many factors that cause decay. There are many parameters for the manufacturer to evaluate the battery state. It is possible to achieve absolute scientific rigor, but it is just an estimation of the battery performance by the engineer, which is finally presented in the performance of full battery life. To put it more bluntly, it is necessary to estimate the performance of the battery, and finally condense it into a number, which is very difficult and impossible to be absolutely scientific and reasonable, so the “display attenuation” of full power can only be used as a reference.
3. Facing the “methodology” of decay
1. Don’t worry about the attenuation (intuitively, the battery life of the fully charged display is reduced)
The displayed battery life represents a number. It’s not necessarily accurate, so don’t be depressed. Think to yourself: I used to be able to charge my car to 501km , but now it can only charge 495km . It’s really not necessary at all. First of all, you can’t change the law of natural decay, and secondly, you know better than anyone how “ruthless” you are when using your car, so don’t compare yourself horizontally with others: how can you be dissatisfied after running X 10,000 kilometers, and how can others” fully charged”? The difference between people is also very big. For example, if you run 40,000 kilometers, the battery degradation situation may not be exactly the same.
2. The “attenuation” of trams is more “conscience” than oil cars
Oil trucks also have “attenuation”. After running hundreds of thousands or hundreds of thousands of kilometers, the engine has to be overhauled, and major maintenance is required in the middle, and the fuel consumption will continue to increase, but the oil truck will not pass full power.” The figure of “showing battery life” is too intuitive to reflect “attenuation”, so it also caused the “attenuation anxiety” of tram owners, and then felt that the tram was unreliable. The attenuation of an oil car is a frog boiled in warm water, and the attenuation of a tram is mainly due to the decline of battery performance. In comparison, this “more intuitive” attenuation is also more “conscience”.
3. The way to use the car that suits you is the best
Don’t think that buying an EV is just buying a “baby”, or just use the car according to the driving style that suits you. However, as a car owner, you must understand the characteristics and laws of trams, know what they are, but also know why, so that you will not be blindly anxious. Over time, you will find that there are many places in trams that are more attractive than gasoline cars.
Post time: May-25-2022