What are the steps to create a vehicle with an NEDC range exceeding 700 km?

If we stand at the end of 2017, when mainstream electric cars can travel around 300 km on a single charge, it is hard for me to imagine that pure electric cars in 2020 could reach a range of 700 km. But Tesla and Xpeng have achieved it.

After I saw Xpeng P7’s range breakthrough of 700 km, I asked my colleagues a question: If you were given a chance to build an electric car at the end of 2017, what kind of car would you make and what range would you plan for?

Except for some unserious colleagues who gave impulsive and hindsight answers, the rest chose to build an SUV with a target range of 500-600 km.

However, Xpeng chose to build a medium-sized sport sedan with a target NEDC range of 550 km. Does this differ greatly from P7’s current achievement?

Let’s start with the first story:

Xpeng P7 was initiated in late 2017. At the initial meeting, many people hoped to build an SUV.

After all, from a market perspective, the Chinese SUV market was in a rapid growth stage at the end of 2017. The sales volume of SUV models increased steadily by more than 10% compared with 2016, and by the end of 2017, the percentage of SUV models in total car sales had exceeded 44%.

Moreover, without major breakthroughs in battery energy density, the battery pack under the floor of an electric car would occupy at least 15 cm of height. Building an SUV could not only leave more space for the battery but also for the passenger cabin. The extra height of an SUV could greatly reduce the impact of the battery on the vehicle’s internal space, and also greatly reduce the technical threshold.

To sum up, NIO’s first car, ES8, is an SUV.* NIO’s second car, ES6 – SUV

WM Motor’s first car, EX5 – SUV
WM Motor’s second car, EX6 – SUV
IDEAL’s first car, ONE – SUV
AIWAYS’ first car, U5 – SUV
SkyDrive’s first car, ME7 – SUV

Therefore, standing at the end of 2017, the difficulty of developing an SUV model is obviously much smaller, which is also the choice of more than 80% of new car manufacturers.

However, in the end, He XPeng, Chairman and CEO of XPeng Motors, made the decision, “Since pure electric SUVs will become a fiercely competitive market in the future, we might as well enter a blue ocean market.”

The “pure electric sports car” that no one has done is a blue ocean, and He XPeng hopes to make a “pure electric sports car” targeting the high-end market.

If you understand He XPeng’s strategic planning for XPeng Motors, you can understand this seemingly unwise choice in 2017.

In an interview with Automotive Business Review, He XPeng said:

“In the later stage of China’s auto industry, if we cannot go up the brand chain, we will have no margins, and no margins means no research and development, and no research and development means no differentiation. This is a positive cycle. So, the more you emphasize cost-effectiveness, the less differentiation you will have. If you don’t have differentiation, how can you really grow stronger?”

XPeng Motors’ goal is very clear. If China’s auto industry wants to achieve overtaking on a bend by electrification and intelligence, car companies must achieve upward breakthroughs. “Only with a higher brand premium can we have more margins, car companies can have enough funds to do more research and development, and with enough investment in research and development, they can produce more valuable products, which will enable enterprises to enter into a virtuous circle.”

Therefore, XPeng P7 is a very important model for XPeng Motors to break through.

In XPeng Motors’ view, the P7 is a mid-to-high-end sedan that is aimed at people who value its endurance capacity, and since electric cars are still in the penetration stage in the Chinese market, endurance capacity remains a very important indicator.

At the beginning of the project, XPeng set an endurance target of 550 kilometers internally, but battery technology and the ability to control power consumption have developed very rapidly in recent years, and XPeng has raised P7’s target range more than once internally.

Liu Minghui, vice president of XPeng Motors, told us:Last year, XPeng Motors aimed for a range of 650 km for the P7; however, through constant effort and optimization, they eventually achieved a range of 706 km. Developing electric vehicles is different from traditional cars. For traditional cars, the specs such as the acceleration, top speed, fuel tank size, and range are fixed from the start. In contrast, due to the fast development of battery and related energy-saving technologies, electric vehicles, especially the range, require a development process. Nonetheless, XPeng Motors has always regarded long range as an important indicator from the start, striving to achieve the best.

This is one of the core differentiations that XPeng Motors hopes to achieve, and it is also an important support for its brand upgrade.

Now that the goal is clear, the remaining task is to achieve these objectives through technological means. XPeng Motors has two means to achieve a longer range: “bigger battery” and “lower energy consumption”.

In terms of battery selection, XPeng Motors has drawn up a new option for itself.

If we only consider the 2996mm wheelbase of the P7, fitting an 80.87 kWh battery wouldn’t be difficult. However, people overlook a crucial point: this is a “sedan.”

Let us answer a question first: why is there no pure electric sedan except for Tesla?

Don’t argue; I’m talking about a pure electric sedan developed based on a pure electric platform.

The answer is that “they are limited by the height of the battery”.

Compared to SUVs, sedans have a significantly lower height; therefore, “the height of the battery pack is highly restricted.” If you take a closer look, most pure electric sedans currently on the road that are based on a traditional gasoline car platform may not significantly affect passenger space; however, if you lie down and observe the chassis from below, you will notice that there is a battery pack hanging beneath, which is quite noticeable.

The Tesla Model 3 and Model S have a height of 1443mm and 1445mm, respectively. In order to ensure that the overall shape of the P7 resembles a smooth sedan style, XPeng Motors set the height of the car at 1448 mm. However, while achieving a relatively low body style, its passenger space and ride comfort cannot be sacrificed. Neither can its ground clearance to maintain off-road ability. Therefore, the space left for the battery pack is extremely limited.

In the game of “vehicle height”, “interior space”, “ground clearance,” and “battery height,” the first three are differentiated and immediately perceptible to consumers. To avoid sacrificing user experience, the only area that can be sacrificed is the height of the battery.The cylindrical batteries used by Tesla are only 65-70 mm in height, and after being grouped into a Pack, the height is lower than 120 mm. Therefore, they have a natural advantage in height. The mainstream batteries in China are all square-shaped, with a height exceeding 100 mm. After being grouped into a Pack, their height is 140 mm-200 mm, only suitable for SUV models and cannot meet the height requirements of the XPeng P7.

So for automakers like XPeng who do not manufacture batteries, they have only two choices: first, switch to lower cylindrical batteries; second, cooperate with battery manufacturers to develop a lower shell square battery.

After weighing the technical competitiveness, supplier resources, development costs, and other factors, XPeng chose to work with CATL to develop a new type of high-density battery with a lower height.

For XPeng, this is obviously a difficult decision.

Because XPeng is not only facing high development costs but also betting on future profit margins.

As a popular battery manufacturer, CATL has a constant stream of customers coming to them and no reason to spend money developing such a low-height battery for XPeng, so this cost can only be borne by XPeng.

Although the cost is high, XPeng did not back down in order to achieve differentiation. Liu Minghui, Vice President of XPeng, told us that the height of the XPeng P7 battery pack is around 110 mm, which is currently the lowest in China. Coupled with the CATL 590 large module scheme, the energy density of the Pack can still reach 170 Wh/kg, and this battery is also the first to debut in the XPeng P7.

For XPeng, the earlier they use new technologies, the earlier they can occupy users’ minds, just like the 811 battery war in the automotive circle in 2019 and the Snapdragon 865 chip war in the smartphone circle. Whoever uses it first will lead.

But the bigger challenge is, how to reduce the manufacturing cost of the battery after mass production?

Liu Minghui, Vice President of XPeng, also admitted that if only XPeng uses this battery, the scale is not enough and it will affect its competitiveness in terms of cost.

Therefore, XPeng’s decision involves whether other brands will use this battery in the future, as well as the future usage volume of this battery. For XPeng, only when the demand for “low-height batteries” increases in the future, the production capacity is continuously increased, a certain scale is achieved, and the manufacturing cost of the battery is likely to be reduced. Only then can XPeng P7 obtain sufficient gross profit.# Decision-making of Automotive Engineering: A High-stakes Game

The decision-making in automotive engineering has low tolerance for errors. Once the direction is determined, heavy investment will be made, which is a gamble for the future profit margin. Liu Minghui expressed that there is sufficient confidence as multiple car manufacturers have expressed great interest in this battery cell and pack platform.

In the battery cell selection test, XPeng has drawn up a new option, which is to integrate a battery of 80.87 kWh into a body of 2996 mm wheelbase and 110 mm height.

Although accommodating an 80.87 kWh battery inside the XPeng P7 is challenging in terms of space, a range of 706 km on NEDC test cycle is hardly convincing. Here comes the second approach – lowering energy consumption.

The Secret to Energy Efficiency in XPeng P7

Before we talk about energy efficiency, it is necessary to clarify one concept: NEDC range does not equal actual range. NEDC range is simply a data point tested under predetermined conditions by the Ministry of Industry and Information Technology (MIIT), while real range is largely dependent on the driver’s usage condition.

Although NEDC range does not equal actual range, it is still useful for cross-model comparisons.

XPeng has reported that in February this year, a test conducted in an air-conditioned environment at around 20℃ yielded a range of approximately 600 km, including both high-speed and urban conditions.

Low energy consumption is achieved through various ways.

Firstly, the vehicle type itself. The P7 is a mid-size sedan, and it has the natural advantage of weighing less than 2 tons and having a wind resistance coefficient of 0.236 Cd compared to SUVs.

Secondly, the efficiency of electric drive. The XPeng P7 is the first EV to implement the three-in-one integrated design, with a common platform for front and rear electric drives. What advantages does this design bring to energy consumption?

Firstly, it reduces weight after integration. Secondly, the high voltage line between the motor and the electric control unit is removed, which effectively reduces line losses.The second aspect is about the motor. Combining with the overall vehicle working condition, electromagnetism and cooling design have been optimized. By matching with the IGBT module of the electric control system, the distribution of copper and iron loss of the motor has been reasonably optimized, which makes the high-efficiency running range of the motor larger.

The third aspect is about the reducer. Being the first one in China, it adopts the design of an external cooling water channel. Through the cooling of the external water channel, the amount of lubricating oil can be reduced, and the oil-stirring loss can also be reduced.

Another very important point is that the secret to the strong power performance of the P7 lies in its IGBT. For the performance version of the P7, its maximum output power reaches 316 kW, which exceeds that of most of the pure electric vehicles in the market. In order to achieve this, XPeng Motors has adopted Infineon 950A IGBT. The company also informed that the P7 is the world’s first vehicle model to adopt Infineon 950A IGBT.

At this point, you may have a question. How did NIO ES8 and Tesla Model 3 achieve the maximum output power of over 300 kW before the P7 was launched?

NIO ES8 adopted two 820A IGBT in parallel to achieve the maximum output power of 480 kW. At that time, limited by technology, this was the solution that NIO had. With the development of technology, Infineon has developed power devices that can bear 950A current. Compared with using two 820A IGBT in parallel, using a 950A IGBT can not only achieve a more compact structure but also reduce the cost.

As for why XPeng Motors did not choose to use more efficient SiC as a power semiconductor like the Model 3 did, the company thinks that from the current industry and supply chain situation, the efficiency improvement is limited and the cost increase of SiC is significant, which makes it not cost-effective for mass production in 2020.

Finally, let’s talk about the question that everyone is most curious about. The P7 models with a range of 656 km and 706 km have the same battery capacity. So where does the extra 50 km come from?

There are three reasons, according to XPeng Motors. First of all, the 706 km range version is equipped with low rolling resistance tires and low air resistance hub. The lower driving resistance can greatly improve the range to some extent.Secondly, because the 706 km range model is a basic model, it does not come with the XPilot auxiliary driving system or the high-power Dynaudio sound system. These reductions in electronics have saved some power, and the lower-end model is also slightly lighter in weight.

Thirdly, the 706 km range has been optimized in terms of control strategy. For example, the P7’s electronic control strategy turns off the motor controller when the car is parked to reduce power consumption. Secondly, the P7’s kinetic energy recovery function can continue until it is close to stopping, and it performs well in terms of driving.

Final thoughts

From the model positioning to exterior design, range to battery technology, from auxiliary driving to intelligence, it is clear that P7 is a car that XPeng has spent a lot of effort crafting. But within the two years of P7 development, Tesla opened factories in China.

XPeng’s Vice President Liu Minghui did not hesitate to tell us:

“Whether it was then (2017) or now, we believe that Tesla’s Model 3 has the best electric power system at home and abroad, and based on its balance of cost and performance, i.e. its overall competitiveness, we believe that the electric drive system of Model 3 should be competitive, and we have benchmarked ourselves against it in many indicators.“

XPeng has chosen a strong opponent for itself, but it has also achieved remarkable success.

From the latest tax exemption list issued by the Ministry of Industry and Information Technology, the domestically produced long-range version of the Model 3 is ready for launch, which means it will be on the market in April and inevitably compete with the XPeng P7, which will be delivered in June.

Although the two models are highly overlapping in terms of model positioning, there are differences in exterior design, detailed configuration, and final price. There is no one-size-fits-all solution in this market segment, and we wait for the market to give us the answer.

Authored by: 63

Edited by: DJ