Text|No. 7-Song
Cars are large pieces, and of course the longer the lifespan, the better.
In the era of fuel vehicles, we don't seem to have been worried. According to the latest scrapping regulations for private cars, the 15-year mandatory scrapping period will be abolished, and the scrapping will be guided after the mileage reaches 600,000 kilometers. Now it seems that only policy factors are the only factors that make a fuel vehicle stop running.
It is said to guide scrapping because the vehicle must pass the annual review, and after the inspection and safety standards are met, the vehicle can be used normally.
But what about new energy vehicles? Looking at the miserable residual value of second-hand cars, the service life of new energy vehicles is generally not optimistic.
What determines the life of a new energy vehicle
In theory, all parts on the car can be constantly replaced, as long as the body is not smashed, the car can be used forever, so this part is not within the scope of today's discussion.
Cars are divided by parts, large and small can be disassembled into thousands of parts, although new energy vehicles have done a lot of subtraction, but still a huge number.
Although there are many parts, the dimension that determines their life is the same -
1. Working life;
2. Durable environment.
"Working life" is like how long the battery can be charged and discharged, and how many times the window can be raised and lowered, all of which are caused by the consumption caused by its own operation. If the consumption is too large, the working life is not high.
"Environmental durability" is like living in Suzhou and Hangzhou, which has a pleasant climate, and has a higher average life expectancy than living in the desert.
Most of the parts of the car are verified for "working life", and most of them aim for 10~15 years. For example, the entry and exit durability test of car seats, which can verify the life of car seat covers and cushions, and judge whether it will be damaged and collapsed after a certain period of time.
Generally speaking, the requirement for this type of test is about 10,000 times. According to the average daily entry and exit 2~4 times, the life span is about 8~14 years.
Regarding "environmental durability", manufacturers usually pass the three high limit tests of the car (high temperature, plateau, and cold), and the most cruel environment can ensure a service life of about 10 years, so there is no need to worry.
Most of the parts of new energy vehicles and traditional fuel vehicles are universal, except for the three electric parts, many of them can be equivalent and interchangeable, so except for the three electric (battery, electric drive, electronic control) part, the target life of other parts can be maintained for about 10 years.
Determines the life of new energy vehicles
It's the "powertrain"
Now it seems that it is the power part that directly determines the life of a car.
Fuel vehicles are no exception, and now the new policy has introduced the OBD system to restrict it. OBD, which stands for on-board diagnostic system, refers to a diagnostic system integrated in the engine control system that can monitor faulty parts that affect exhaust emissions and the main functional status of the engine. The testing center uses this system to test the private car and decide whether the car is to be scrapped.
However, for new energy vehicles, there is no direct means such as emissions to evaluate their lifespan.
If only according to the service life, there is an 8-year mandatory scrapping provision for new energy vehicles of a real operating nature, but most domestic new energy vehicles are mainly non-operational family cars, and their service life can reach 600,000 kilometers.
At present, the average annual mileage of mainland family cars is about 13,000 kilometers, and it takes 46 years to drive to 600,000 kilometers, as long as the core components such as the three electric systems of new energy vehicles are normal, it is no problem to open for 10 years and 8 years.
Therefore, the key to life refers to the three electric systems.
The life of electric drive and electronic control modules is relatively high, and the short board is the battery. The national new energy vehicle battery attenuation regulations are that during the warranty period, the performance attenuation of the battery cannot exceed 20%, otherwise the manufacturer will replace the battery for the owner free of charge.
However, it should be known that there is currently no national standard for the strict evaluation standard for battery attenuation, which directly leads to different car companies' identification methods and methods for battery attenuation.
It is recommended that you pay more attention to the battery use attenuation data released by car companies. For example, Tesla is doing relevant data sharing, and the attenuation is the fastest in the first 40,000 kilometers, with about 5% attenuation.
After 40,000 km, the decay rate tends to flatten. Within 320,000 kilometers, the battery attenuation is within 15%, and beyond 320,000 kilometers, the battery attenuation may exceed 20%.
Practice the golden eye of fire
You need to pay attention to the temperature control of the battery
At this stage, the manufacturers that release battery attenuation data have not yet formed a scale, which can only force us consumers to have some basic understanding of new energy vehicle technology.
To practice the golden eye of fire, we need to pay attention to the battery temperature control ability.
Just like the "environmental durability" we mentioned above, we better put the power battery "in" in Suzhou and Hangzhou, which has a pleasant climate.
Because high temperature will affect the life and safety of the battery, low temperature will affect the charging and discharging capacity of the battery.
The goal of power battery temperature control is to keep the power battery in good working condition, for example, the ideal working temperature of lithium batteries is 20~40 °C.
In order to prevent overheating caused by long-term high-current charging, BMS battery management technology comes in handy, which switches the charging mode to constant voltage mode when the battery capacity is charged to about 80%.
Because the regulation of current and voltage alone is not enough to control the temperature within an appropriate range, cooling is also required to take away heat during the fast charging process.
The most important thing here is the liquid cooling method, which can control the battery temperature more accurately and adjust the temperature faster than the ancient mode of air cooling.
We know that ternary lithium batteries have better discharge performance than lithium iron phosphate batteries because of better low temperature adaptability, but the capacity of the battery when discharged at a rate of 0.2C in a -20 °C environment is still about 25% lower than that at room temperature of 25 °C, so we need to heat up the battery.
To solve this problem, the battery is designed with self-heating technology. The most important thing here is the heat pump air conditioner, because the essence of PTC is to heat itself, it will compete with the cruising range for battery power, so it is nicknamed the little sun.
The essence of heat pump is heat porter, heat pump technology is more like household air conditioning, COP (energy efficiency ratio) is 2~3 times better than the former. At the level of LYRIQ, the COP (energy efficiency ratio) can be achieved by as much as 5 times.
LYRIQ goes a step further than the traditional way of thinking, and has two solutions to solve the low temperature problem.
When there is residual heat from the motor battery, the system will carry the heat of the battery and motor to heat the passenger compartment. The system converts the electrical energy of the charging pile into thermal energy and stores it in the system battery and waterway, which can support the heating of the passenger compartment for short trips of 1-2 hours.
WHEN YOU'RE DRIVING AT LOW SPEEDS OVER LONG DISTANCES, THE RESS HEATER (6KW) IS ACTIVATED TO HEAT THE PASSENGER COMPARTMENT AS NEEDED, WHICH IS WHERE THE PTC AUXILIARY HEAT IS USED.
Note that the low-speed driving mentioned here is low-speed driving, because if the speed exceeds 100KPH, the residual heat of the motor and battery can basically meet the demand, and there is no need to drive PTC.
Considering that the heat pump is easy to fail when the ambient temperature is too low, Tesla has also made magic changes, in addition to extracting external air heat, but also relying on the eight-way reversing valve to absorb the waste heat generated by the power battery system and drive system.
summary
In addition to "cruising range anxiety", we also have "car life anxiety", in fact, new energy vehicles are not so unbearable, except for the battery part, most of the service life is comparable to fuel vehicles.
However, there is still a long way to go for new energy vehicles to reach the level of making consumers anxious, especially battery life, whether it is regulatory requirements or battery technology, the industry needs to work together.