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Introduction
Introduce the topic briefly.
Battery Swapping vs Supercharging
Explain the pros and cons of battery swapping and supercharging.
Chinese Market
Describe the state of battery swapping and supercharging in the Chinese EV market.
Challenges
Discuss the challenges of implementing a widespread battery swapping infrastructure, including technological limitations and logistical challenges.
Conclusion
Summarize the key points and provide a concluding thought.Taking the well-established Nio as an example, from the flagship ES8 and ET7 that are over five meters long to the entry-level ET5 or SUVs of similar size, regardless of the brand’s largest or smallest model or highest-end to entry-level, they all use battery packs of the same physical size. Nio’s division of battery capacity and range completely depends on the high or low energy density of its internal battery cells.
There are two sides to every coin. On the one hand, this has a positive effect, prompting Nio to have a stronger demand to improve the overall energy density of the battery pack, thus taking the lead in NCM811, semi-solid-state, and ternary/lithium-iron mixed technology. However, on the other hand, it also makes Nio’s current product line exhibit a small embarrassment of “battery range reversal.”
Since battery swapping is universal, and optional battery packs are universal, if the same battery pack is used, the larger and heavier ES8’s range will definitely not be as good as that of the smaller and lighter ES6. The same applies to the ET7 and ET5 on the second-generation platform. No matter which battery pack is chosen, the range data of the latter will always exceed that of the “big brother.” “High-end cars cannot outrun low-end cars,” and this flips the market norms.
This range reversal leads to two real consequences: first, it adds difficulty to improving the competitiveness of high-end models, and second, it limits the space for brand expansion downwards.
In the current situation where battery technology has not made a leap, the volume of the battery pack is directly proportional to its energy level. Similarly, the wheelbase of the vehicle is directly proportional to the volume of the battery pack when laid flat on the chassis. Therefore, the size of the vehicle, especially the wheelbase length, largely determines the maximum range of the vehicle. Battery packs with different physical sizes are needed to achieve maximum range for different levels and sizes of vehicles, and of course, this maximum energy/maximum range limit is also different.
If a battery pack of a uniform physical size is used to cover high- and low-level vehicles with different sizes/wheelbases, it is inevitable that some will be ignored. Battery packs that are too small result in larger and high-end cars not maximizing their battery capacity. Battery packs that are too large result in the smallest car model within the swapping system being too large and unable to enter markets below its segment.
In practice, the physical size and specifications of the battery pack for a swapping system are generally determined by the lowest and smallest car models planned in that system. And this “lower limit car model” often also has the best range in the system. The larger and higher-end models above it usually have a disadvantage in terms of battery volume, capacity, and range. This “disadvantage” is both the range reversal within the system and a relative disadvantage compared to competitors who can “fully load” their battery capacity without swapping.Assuming the physical size of N brand’s swappable battery pack is x meters * y meters, which happens to be the maximum size that a mid-size SUV can use. However, N brand’s full-size SUV can only use the same size battery pack for swapping, while competing full-size SUVs that don’t offer swappable batteries can carry battery packs of (x+1) meters * (y+1) meters, which gives them an advantage in range in the higher-end market, unless there is a significant advantage in battery efficiency.
Of course, the above theoretical advantages and disadvantages are not absolute. As a pioneer in the battery swap route, NIO is forced to improve its battery energy density and actively seek new technologies, which is in line with its high-end brand positioning. On the other hand, there is the full coverage of the battery swap network, which weakens the significance of vehicle range, and thus weakens the power disadvantage of high-end models compared to same-class competitors.
However, even with the most advanced battery pack currently available from NIO, ES8 and ET7, the flagship models of the brand, are still limited to “only” 100kWh due to the physical size limitation of the battery pack. Under the same technology conditions, it’s not uncommon for electric cars of the same size/wheelbase to have 110-120kWh of battery capacity.
The space for downward expansion is limited in a hard way. For example, the length of NIO’s battery pack is 2062mm, and the wheel diameter is conservatively calculated as 500mm for 20 inches. Because the battery pack needs to be placed between the front and rear wheels, the wheelbase must be at least 2.6 meters. The wheelbase of all NIO models is less than 200mm, between 2888mm and 3060mm.
Because the swappable battery system restricts the size and upper limit of the battery, the wider the range of vehicle sizes of a product line, the more struggle there will be in the high and low-end of the product line. The limitations of the swappable battery system are not enough to support a product line spanning from 7 series to 5 series to 3 series to 1 series, like BBA does to cover a price range from one million to two hundred thousand.
Therefore, creating a new sub-brand with a lower positioning, not significantly reducing vehicle size, but cutting performance configuration becomes a more suitable approach. Therefore, we see that NIO has already planned the third low-end brand, using multiple brands rather than more body sizes to delineate high and low levels, in order to enter new price points and market segments.
Modularity is not a panacea.Ningde Times’ EVOGO battery swap system brings a new idea. Since the single specification battery pack has too narrow an application range, the battery pack is designed into three modules, which can be freely combined to provide flexible range and greatly expanded vehicle adaptability. But this design has not been recognized before for good reasons.
When the battery pack is divided into three parts, the battery pack changes from a large housing to three small housings. Each of the three modules needs to be reinforced and sealed to meet various safety standards. So, 1+1+1 > 3, which naturally increases the proportion of non-core components, lowers the energy density of the entire pack, and can hinder high-end electric vehicles pursuit of long range and high performance.
The inside of the battery pack is not only the core, which can be divided into parts at will. For example, after dividing into multiple modules, the high-voltage lines and cooling pipes (for water-cooled battery packs) inside the original battery pack are also separated, so interfaces between modules need to be added. Since the modules are interchangeable, these interfaces need to be completely sealed when not in use.
If each module can be freely replaced and called, 3 modules need 3-6 external interfaces to achieve connectivity between modules. For water-cooled battery packs, too many pipeline openings are not good for reliability, which further reduces the overall efficiency. Using air cooling can avoid this problem, but at the expense of charge and discharge performance.
Aiways once had a more extreme idea, a “main + auxiliary” dual battery pack: the main battery pack is no different from a regular electric vehicle, and the 18 kWh auxiliary battery pack located at the bottom of the trunk can be removed and replaced, which can be rented at the 4S store before a long trip. However, because the auxiliary battery pack was too simple to support normal driving alone, it could only be used in emergencies to extend the range. This design quietly disappeared, and could not be found on the official website.
In short, modularity is not magic, and the fact that no one has gone this way before does not mean everyone is stupid. The benefits and troubles of modular design coexist. Currently, modular battery swapping is only suitable, or more suitable for some vehicle models that do not pursue performance and do not need to squeeze the limits of battery technology. This will certainly promote the development of the swapping system, but it cannot be regarded as a magic weapon to change the world.
It’s good not to follow the mainstreamSince battery swapping has its limitations (compared to issues such as battery ownership, which are more subjective), why are car companies and Tier1 suppliers so focused on it? Going back to the original question, can the battery swap trend last?
We need to look at both sides of the issue. While the challenges and limitations of battery swapping come with its advantages, discussing the “bad aspects” of battery swapping doesn’t mean that it is useless.
For NIO, having a narrow product lineup and a multi-brand hierarchical strategy is a natural result of battery swapping and was an active choice when they first decided to adopt the technology. Both of these factors exist simultaneously, and one cannot be ignored because of the other’s existence.
The pros and cons of a unified battery swapping standard do not always completely determine the actual outcomes. The market competition is always dynamic, systematic, and subjectively controllable. We cannot conclude that battery swapping always works in a specific way in a simple manner.
For example, although the battery pack specifications caused NIO to fall behind with a 100+ kWh battery pack (150 kWh is not yet available), their early establishment of a dense battery swapping network was an added benefit. This, in turn, weakens the significance of NIO’s pursuit of extended range, and the existence of a battery swapping network mitigates any disadvantages they may have had in terms of range.
More importantly, as discussed in “I Can Do a 1000km Range, but I Won’t Give it to You,” the value of achieving the longest possible range in electric vehicles today varies due to differences in infrastructure. For example, Model 3 has a competitive edge with a 450-500km range, and for car companies that have self-sustaining charging solutions, maximum range is no longer essential.
Lithium-ion batteries are also an expensive component, and even if an electric vehicle has a 3-meter wheelbase, filling it with batteries would still require cost and pricing allowances in addition to space. More and more electric vehicles are designed with “footwells” and “lying down” battery packs, indicating that the era of electric vehicles stacking batteries at all costs is coming to an end.
The Volkswagen ID battery pack, for example, can have a few modulations left empty to launch lower-cost models, and the ID.3 did not utilize all of the floor space. Since conventional EVs that do not use battery swapping are now also wavering on “battery stacking,” the battery swap camp with a battery swapping network may not necessarily be anxious about the underutilization of chassis space caused by unified battery pack specifications.Single battery standard has limited product line width. But nowadays, the mid-to-low-end market is becoming less important, especially for luxury brands. Moreover, NIO’s existing wheelbase range has probably not utilized the limit allowed by this battery swap standard. Multiple brand strategy requires a new sign, which may bring some challenges and risks. However, this cannot be understood as a helplessness, but rather a neutral choice based on oneself.
The battery swap itself does not have any problems. It is like non-battery swap, with gains and losses, all depending on how to use it. Under NIO’s positioning, design, and operation, the single battery standard does not show any inherent disadvantage. Even the reverse ranking of battery life may not be noticed. Modular battery swap is perfect for economical cars that do not require high performance, have a significant cost-performance ratio, and are outstanding in commuting properties, which Ningde era has solved with EVOGO to help original equipment manufacturers.
The problem is to regard battery swap as a “magic pill” that can change everything and thus dominate everything, as an absolute substitute for non-battery swap. This is the mistake of “always wanting to win before the war begins” as mentioned by Captain America. “Whether you can wait for the tailwind” has no answer because the problem itself should not exist.
When there is no wind, everything seems like a tailwind.
This article is a translation by ChatGPT of a Chinese report from 42HOW. If you have any questions about it, please email bd@42how.com.