In 2023, what will Chinese people be most concerned about when buying pure electric vehicles? If we only look at public opinion, the answer should revolve around the word "smart", such as how many TOPS the computing power of the car's computer chip is, how many screens there are in the car, how many inches the largest screen is, how many commands the voice assistant can recognize, how many lidars there are in the car, and whether the car can drive itself to a parking space and park it.
But in fact, the core concerns of the Chinese people who buy pure electric vehicles this year are no different from those of the wave of people five years ago. They are still the same as these four words:
Range anxiety.
CCTV's "China's Better Life Survey" program team found that 66.93% of Chinese people give top priority to cruising range when purchasing new energy vehicles.
If we look at the world, Chinese people are not the group with the strongest range anxiety on the planet.
The "2023 Global Automotive Consumer Survey" released by the consulting agency Deloitte in February this year showed that among all users surveyed worldwide, 57% of German users, 43% of Japanese and Southeast Asian users, and 48% of American users were most concerned about cruising range. Chinese users, on the other hand, put the battery safety of pure electric vehicles first and seem less anxious.
So, is there any solution to the epic problem of "range anxiety" that has caused pure electric vehicle users around the world to "sit hot and cold"?
some.
The simplest and crudest way is:Stack batteries.The reason is simple. As long as the battery capacity is increased, the cruising range can be extended. Theoretically, as long as the battery is big enough, a pure electric car can keep running around the earth, with four new tires and a driver from time to time.
Many car companies do this in the early stages of building cars. However, the greater the battery capacity, the higher the cost will be transferred to the user. Most people buy a pure electric vehicle mainly for the sake of affordability. Buying a petrol vehicle with a range of 700 kilometers can cost 100,000 yuan. But if you buy a pure electric car at the same price, 400 kilometers is considered to be the best.
Not everyone who has too much money to spend knows how to choose.
Moreover, even leaving aside the cost of car purchase, the development of battery technology is very slow. For example, battery energy density, which is closely related to battery life, is unlikely to make a leap forward in the short term under current technical conditions, and the degree of improvement is extremely limited.
In this context, smart car companies began to abandon the "difficult but correct" path of battery research, and turned around and embarked on another "seemingly simple but correct" path:
Let's replenish energy quickly.
Not copying Tesla this time
Faster, there are two ways: battery replacement and fast charging.
The battery swapping efficiency is the highest, and the car can be fully charged before you finish a cup of coffee. However, the initial investment is large, the profit model is unclear, the standards are not unified, and it is a typical long-term technical route. For the vast majority of car companies who want to make money as soon as possible, this is not a good choice.
Fast charging is currently the mainstream solution for car companies. According to the electric power formula P=UI, there are two options for increasing fast charging power:
Increase the current I,Tesla’s super fast charging takes this path, using 600A current to achieve 250kW charging power;
Increase the voltage U,The 800V solution launched by Porsche in 2019 uses 350A current to achieve 300kW charging power;
There is a very interesting phenomenon here: According to my understanding, the original intention of Chinese car companies to build electric cars is to be "Tesla spiritual imitators", so they should choose the high-current route without even thinking about it. But the reality is that Chinese car companies have unanimously chosen high voltage, that is, the 800V route.
Why? Two reasons.
First, the high-current fast charging route has high requirements for vehicle thermal management and wiring harnesses.
According to Joule's formula Q=I²Rt, increasing the current will cause the electrical system to heat up quickly, placing a greater burden on the thermal management system. At the same time, the energy conversion efficiency is not high and the damage is serious.
The charging curve of Model SPlaid on the V3 supercharging pile shows this: Tesla Super Fast Charging cannot guarantee that the peak power is 250kW during the entire charging process. It only maintains 250kW when the charging level is in the 10%-32% range. When the charging level is at 40%, 50% and 60% respectively, the charging power is 180kW, 140kW and 115kW.
These two major shortcomings make the high-current fast charging route's two advantages of "less changes to the vehicle end" and "minor transformation of the power grid" seem somewhat unimportant.
Second, the high voltage, that is, the 800V route, not only improves the existing energy replenishment experience, but also opens up the possibility of future upgrades.
First, under the national standard current limit of 250A, the voltage is increased from 400V to 800V, and the charging power can be doubled from 100kW to 200kW, significantly shortening the charging time;
Secondly, under the same charging power, when the voltage is increased to twice the original, the current can be reduced to 1/2, and the cross-sectional area of the wire harness can be reduced accordingly, reducing the cost of the wire harness and the weight of the entire vehicle. Less heat dissipation, which reduces the difficulty of thermal management of the entire vehicle;
Finally, 800V high voltage can be upwardly compatible with the fast charging performance of high-end cars with larger battery capacity;
Here is a rough calculation method: Assume that the internal cell connection method of the battery pack is ignored. A battery pack with a capacity of 100kWh requires a 4C rate. Under a charging gun with a maximum current of 500A, the bus voltage of the 100kWh battery pack is 800V (capacity = current * voltage * charging time).
In terms of configuration, 800V mainly has the following three options:
Solution 1: 800V battery with DC/DC converter.
The Porsche Taycan is a representative model. Its advantage is the existing architecture (battery pack, motor, electronic control, PTC, air conditioning compressor, vehicle
Most of them (chargers, OBC, etc.) can be used. Only the single component of the power battery is upgraded, and the modification cost is low. However, after the voltage is converted to DC/DC, the loss is large and the efficiency is low. Moreover, an additional converter is required, which increases the cost and weight of the vehicle.
Option 2: Dual 400V battery pack.
Two low-voltage battery systems are connected in series at 800V when charging and in parallel at 400V when discharging. This is a transitional solution that is even more obvious than 800V+DC/DC. Apart from upgrading the battery BMS system, there are basically no major changes in the vehicle end. However, both series and parallel connections require high BMS system design, complex control strategies, and slow charging speeds.
Option 3: 800V full series high voltage.
This is the ultimate version of 800V. From the battery pack, motor, charging interface, to OBC, air conditioning compressor, DC/DC and PTC, everything is re-adapted to meet the 800V high-voltage platform. The advantages and disadvantages are very obvious: the advantage is that it can be done in one step, the energy conversion efficiency is the highest, and the energy replenishment experience is the best; the disadvantage is that the replacement cost of parts is high in the short term (at least 2% cost increase), and the battery system safety requirements are high.
Theoretically, car companies directly adopt 800V high-voltage routes for all series from the beginning of design, which is undoubtedly the best solution to quickly solve users' range anxiety.
But theory is theory after all. In practice, 800V does not seem to be as effective as what car companies promote in their advertisements."Instant results".
New type of fraud?
In the 2023 winter test, Icar Di tested five mainstream 800V models: Xiaopeng G6, Avita 11, Haopu GT, Zhiji LS6 and Audi RSe-tronGT. The method is:
1. At minus 30 degrees, the vehicle power is exhausted until the meter shows zero, and the test is started when the vehicle is hot;
2. Use the same third-party liquid-cooled supercharger with an actual power of 400kW to test in sequence;
3. The battery will be reset from zero and the gun will automatically jump. The data statistics range is 0-99% (or when the gun jumps);
This kind of test method is more in line with the scenario where normal users drive to a supercharging station after the vehicle is out of power. After actual testing, we have the following conclusions:
1. Avita 11, which has the largest battery pack capacity (110 degrees), has the shortest charging time. It only took 52 minutes to fully charge. The Haopin GT with the smallest battery capacity (84 degrees Celsius) took 56 minutes to fully charge;
2. The maximum charging power of Haopin GT is close to 213kW, making it a typical "rate master". However, the power during the entire charging process is not stable enough and starts to slow down from SOC 45%, resulting in an average power of only 89kW. Among the five test cars, it is the only one with an average power lower than 90kW. The other one is the "foreign electric car" Audi RSe-tronGT;
3. As an imported car, Audi RSe-tronGT’s local adaptation work is quite inadequate, and it cannot be used on third-party charging piles. If you want to maximize the charging efficiency, it can only be used on officially certified charging piles;
4. The maximum charging power of Xpeng G6 is second only to Haopin GT, but the average power is less than 100kW. This has a lot to do with the unified testing method. Xiaopeng will limit the heating of the passenger compartment at low temperatures and low battery, so that users can maximize battery life and drive to the charging pile. Just like this, the battery temperature will be low, which must be compensated for during the charging process. Although the test suffered a loss, this strategy is the most suitable for user usage scenarios in reality;
5. Most of the so-called 800V models have a maximum allowable voltage of less than 800V during the actual charging process. Xiaopeng and Avita are between 650-700V, and Haopin GT is 746V. Zhiji LS6 is very practical. The maximum allowable voltage is 897.5V. This also brings the charging power to be stable at more than 130kW within the SOC range from 5% to 80%, but it is limited to charging to 95%. This result is quite regrettable.
Based on the test results of five vehicles, the current 800V solution of the car company has improved the user's energy replenishment experience to a certain extent, but it is not as obvious as imagined. Because the maximum energy of overcharging is basically released in the first 50% of the SOC. Once it enters the lower 50%, the impact of overcharging on the charging time is not big.
Moreover, the tolerance of pure electric vehicle users around the world to the expected waiting time threshold for charging is far higher than everyone thinks.
Research also from Deloitte shows that the expected waiting time for surveyed users in most markets, such as the United States, South Korea, Japan, India, and Germany, to charge pure electric vehicles from 0% to 80% in public charging places is 21 to 40 minutes. Among the surveyed users in China, the highest proportion is those who are willing to wait 41 to 60 minutes. Those who actually require waiting time of less than 10 minutes only account for 2% of Chinese users, which is the lowest market share in the world.
This also means,Among people all over the world, the Southeast Asians are the most anxious about charging, and the Chinese are the least anxious.Has it completely subverted your stereotype?
However, it would be too one-sided if we only look at 800V from the single dimension of "charging time". Because of the true power of 800V, in addition to allowing car companies to win marketing battles, it also substantially improves the performance of the entire vehicle.
There have been two relatively heated discussions on this matter on the Internet this year.
The first time was after the official launch of the Xpeng G6 in June this year. A car company executive said, "The issue of 800V charging has been deceived by some companies in the industry. The peak that others say is a wide peak. Only the N7 can truly achieve full-scenario overcharging without relying on high-power charging piles. It also solves the pain points of low-temperature charging speed, greatly improving the battery life as low as minus 20 degrees, and the heating of the in-car air conditioner."
The second time was in November this year, and it was this car company executive who jumped out and said, "The name of the 800V high-voltage platform will inevitably mislead consumers. In fact, it is calledhigh voltage platformmore reasonable. "
In fact, the so-called 800V in the current Chinese automobile industry is exactly the same as what this executive said.It is a "new type of fraud" in which insiders are well aware of the scam and take advantage of information gaps to make money from unknown insiders and outsiders.
There is no conclusion or standard gap in the industry. As long as the peak voltage of the vehicle is within the range of 500V-800V, it dares to call itself "800V".
In fact, the real 800V means that the operating voltage and withstand voltage of the components used in the vehicle can meet the requirements of 800V (including electronic controls, motors, air conditioners, OBCs, DCDCs that support 800V, and all other parts on the high-voltage circuit such as related wiring harnesses and high-voltage connectors are designed, developed, and verified in accordance with 800V requirements).
The gap between the real and fake "800V" is too big.
write at the end
According to the current level of mass-produced 800V pure electric vehicles, it is difficult for users to enjoy the huge improvement in experience brought by the "800V" technology during the 3-5 years of golden car use. Without the self-built supercharging piles of car companies, 800V is like a vase in many scenarios.
And when you ask car companies when superchargers can be built closer to you, the car companies will always smile evilly and say: they will definitely build them next time.
Therefore, when another car company wants to use fancy technology like "800V" to fool you into paying more, you can also use the same rhetoric to fool the car companies:
I will definitely pay more next time!