Pack Analysis: BYD Blade vs CATL Qilin vs Tesla 4680 Structural

Welcome everybody! I'm Jordan Giesige and this is The Limiting Factor. Today I will do a review of Tesla's in-house

4680

structural

battery

pack

compared to the BYD Blade battery and the CATL Qilin battery. The approach I will take is to look at the design of each battery

pack

, the advantages and disadvantages of those designs across six factors, and then on average how each pack design compares on a relative basis. In short, all of these battery packs are practically equal when viewed from the potential of their base architecture. But every architecture has quirks and eccentricities because there are always trade-off decisions with batteries.

However, all battery packs should significantly outperform the latest generation. I'm sure some of you are surprised by the performance of the Tesla

4680

pack here, given that in the last video I showed that the 4680 cell still has a long way to go to meet the expectations set for Battery Day. But, as I said a moment ago, we'll look at this through the lens of each architecture's potential relatively. This is the opposite of where each architecture stands today in absolute terms or how quickly it will develop over time. Later in the video I will explain my thinking here in more detail.

But suffice it to say, there's no way to do a like-for-like comparison of the packages because all we have right now is marketing material. However, based on what each company has shown us, we can see roughly how each pack is built, which can give us an idea of ​​the maximum potential of each battery pack design. Whether BYD, CATL and Tesla can maximize the potential of those designs is a different story, but I'm confident they will because each company has brilliant engineers. Before we start, a special thanks to my Patreon followers and YouTube members. This is the support that gives me the freedom to avoid chasing the algorithm and the sponsors.

As always, support links are in the description. To begin with, some people may wonder why I leave out Ford and GM battery packs. I won't cover those battery packs in this video because they are not in the same league as their counterparts from BYD, CATL and Tesla. Both GM and Ford battery packs enclose the cells in a module before placing them in the pack. The modules are secondary battery packs within the main battery pack. In addition to the modules, GM and Ford also use transverse bracing within the package to create rigidity. BYD, CATL and Tesla have been using the boost-focus module for a decade, but are now abandoning it because they have found better, cheaper ways to build battery packs.

Let's look at some historical context to explain why BYD, CATL and Tesla used modules and reinforcements in the first place, which will lead nicely into the

structural

analysis

of their new packages. Tesla has said in the past that the reason they used modules was because in the early days of electric vehicles, particularly with their roadster, they wanted a way to repair the battery pack if it was faulty because back then, the reliability of the cells and packages was smaller. . The idea was that if modules were used, the module could be swapped out rather than replacing the entire package.

Second, a decade ago, electric vehicle manufacturers were just getting the hang of their first battery packs. It was quite difficult to build a battery pack that actually worked and also met all the thermal, safety, structural and energy density requirements. Therefore, it was easier to assign specific components to specific uses, such as placing cross bracing in the structural package. This made the legacy batteries from BYD, CATL and Tesla more or less similar in their design: cell to module, module to pack and reinforced with cross braces. But now, after 10 years of experience, BYD, CATL and Tesla engineers are removing the modules and cross braces because those components are unnecessary duplication and therefore dead weight.

The cells are placed directly into the pack and the packs do not use cross braces. Simplicity is the ultimate sophistication. That's why I'm not including battery packs from GM and Ford in this

analysis

. They're launching their EVs with overly complex battery packs that their more mature counterparts, like BYD, began abandoning last year, leaving GM and Ford a full generation behind. With that in mind, let's do a quick review of the design of the CATL Qilin, BYD Blade, and Tesla 4680 battery packs. CATL Qilin integrates the foam spacers or thermal pads, the liquid cooling plate, and the cross braces to create what I will call structural cooling.

Structural cooling is placed between each row of battery cells and the battery cells are placed directly into the package without modules. The cells are prismatic or rectangular cells with a hard shell. That is, structural cooling replaces transverse reinforcements and the cells are transported as load. The BYD Blade's battery also uses prismatic cells, but they are long and thin. The cells extend the length of the battery pack and also serve as the structure of the battery pack, replacing steel beams. They look like

blade

s, that's why BYD called it the Blade Battery Pack. Cooling is done with a thermal pad at the bottom of the battery pack, and again, there are no modules.

The Tesla 4680 pack uses hundreds of cylindrical battery cells, and between every two rows of cells is a cooling tape, much like a bullet bandolier. Those shoulder straps are placed in the cell tray, a lid is placed on top, and then polyurethane foam is injected into the package. The polyurethane hardens and the combination of the foam and battery cells forms a honeycomb structure similar to that used in airplane wings. With a basic understanding of the design of the BYD Blade, CATL Qilin and Tesla 4680 packages, let's see how design choices can affect performance characteristics such as rigidity, power density, cooling and safety.

Before getting into the matter, some warnings. As I said at the beginning of the video, I'm going to take a relative approach. That means I won't provide specific values ​​for things like power density or system integration efficiency. There are two reasons for this. First, we don't know the logic behind the marketing specifications or whether they are accurate. I've shown at least two prominent examples of this in previous videos. As I showed in the last 4680 teardown video, Tesla has a long way to go to achieve what they showed at battery day. And, as I explained in my BYD Blade video, the BYD Blade significantly underperforms its marketed specifications.

That is to say, there are so many unknowns, so much hype and so much confusion, that it is an exercise in futility to make a proper comparison between battery packs if we only rely on the marketing material. That brings us to the second, more positive reason why I'm taking a relative approach: at the beginning of the video I said that the package designs of BYD, CATL and Tesla are practically equal when viewed from the potential of their basic architecture. So if all packages are approximately the same, then what is interesting is the reasons why the performance of each package varies across metrics.

This, in turn, encourages us to look at the packs from a first principles perspective to understand the trade-off decisions that were involved in the design of each battery pack. As a final note, I think it's worth pointing out why I won't be including loading speed in my analysis. That's because, in my opinion, over the next decade, the top priority for automakers will simply be sourcing enough battery packs at a reasonable price. As long as the charging rate of their vehicles is competitive with other offerings on the market, the battery packs will sell. And if they have the luxury of choice, I wouldn't put charging speed in the top five priorities for automakers.

Reducing the weight of your vehicles, thermal performance and safety are more important than charging speed. Caveats aside, let's look at how each performance metric is affected by design choices, starting with stiffness. Stiffness is important because the stiffer the architecture of a battery pack, the more weight can be removed from the vehicle. This is because previous generation battery packs not only used cross bracing in the pack, but also used bracing around the pack in the vehicle structure. Next-generation packages eliminate transverse stiffeners, increasing the energy density of the package itself, and reduce vehicle weight by eliminating redundancies between the package and the vehicle structure because they become part of the vehicle structure.

The greater the rigidity of the backpack, the greater the total potential for weight reduction and increased autonomy. Both the BYD and CATL packages appear to use ladder frame designs. In the case of BYD, the ladder frame is provided by the

blade

batteries themselves, while for the CATL Pack, Qilin uses structural cooling. In both cases, the cells will be screwed in place and will probably also use some adhesive for additional reinforcement. In the case of Tesla's 4680 pack, the cells themselves use a reinforced cell can that is about 2 to 3 times thicker than a typical battery cell. There are no bolts or fasteners around the cells.

They are buried in a durable polyurethane foam that is pumped into the backpack. The combination of polyurethane foam and cells forms a super rigid monolithic structure. That monolithic structure should have higher rigidity than a package with a finite number of structural members, which means the Tesla package is the winner here. Moving on to energy density, I will focus on volumetric energy density because we have visual references that provide hints on volume utilization. But the gravimetric energy density should correlate quite well. The Tesla package uses very compact cylindrical cells in a hexagonal arrangement within a rectangular enclosure, meaning the maximum packaging density is approximately 91%.

The BYD Blade and CATL Qilin packs use rectangular prismatic cells in a rectangular enclosure, maximizing volumetric power density. Rectangular cells in a rectangular enclosure are the clear winners in terms of packing density. But we must also take into account the chemistry of the battery. Nickel-based cells store 40% to 50% more energy than iron-based cells. The CATL Qilin battery pack can use high energy nickel or low energy iron depending on the use case. For now, Tesla is using high-energy nickel cells for its first battery pack and BYD is using low-energy iron cells in its blade pack. This means that Qilin packages that use nickel cells will have the highest energy density because they use high energy density cells in a high density packaging arrangement.

The Tesla 4680 package will take second place because it uses high energy density nickel cells in a low density packaging arrangement. The iron-based Qilin and Blade packages tie for third because they use low-energy cells in a high-density packaging arrangement. As for cooling, the BYD Blade uses plate cooling at the bottom of its packages. This is a suboptimal cooling arrangement. As CATL rightly points out in their presentation, cooling the sides of the prismatic cells instead of just the base increases the cooling area by 4 times. The Tesla pack also uses side cooling, but it only cools about 20% of the cell.

That's better than basic cooling, but not as good as cooling the entire cell side like Qilin. CATL Qilin seems to have the best cooling, Tesla second and BYD Blade last. If you want the full story on why side cooling is better, check out my Ribbon Cooling video. Let's move on to security. What do I mean by security? I am referring to the mechanisms established to curb the spread of thermal runaway within a battery cell and also between battery cells. By thermal runaway I mean the battery cells overheat or explode. Security is a sensitive topic, so I'll start with some context.

Vehicles that use BYD, CATL, and Tesla battery packs will have a lower chance of catching fire than internal combustion vehicles, so I would feel safe driving a vehicle that uses any of their battery packs. And, regardless of the probability, electric vehicle battery packs are designed to keep vehicle passengers safe duringa certain period of time, but the more time you have to get out of or away from the vehicle, the better. And that's my focus in this video. Why build security into this? First, electric vehicle fires garner a disproportionate amount of negative media attention. Secondly, maintaining passenger safety should always be the top priority.

And third, increasing energy density creates security challenges. All battery pack manufacturers seek to maximize the energy density and therefore the performance of a battery pack, but they also have to deal with their ability to safely control that energy. The ideal is to have high energy density and high security, but those two factors act in opposition to each other, meaning that it is difficult to improve energy density and security at the same time. There is a false assumption, particularly with the hype around solid-state batteries, that it is possible to make a battery that is 100% safe. It's not, because batteries store a huge amount of energy.

Generally, EV fires occur when the pack is pulverized in a high-speed car accident and several cells are damaged at once, which is why the nail-prick test shown here is not necessarily a good indicator of safety in the real world. But even if the vehicle is not involved in an accident, battery cells and packs can spontaneously catch fire due to manufacturing defects and poor quality control. I have no information about the quality and control processes of BYD, CATL and Tesla, so I will not include them in my safety rating. So again, what I'll be looking at specifically is how well they can control thermal runaway when this happens, based on what I can see in the marketing material.

As a final note, battery safety is a science in itself and the safety analysis I will do at this time is not safety advice. Each new battery pack is a complex, multi-scale thermal and electrochemical system, and manufacturers don't know exactly how their pack will perform in real life until there are thousands of them in circulation for several years. As I mentioned before, there are two broad classes of lithium-ion batteries – Iron and Nickel. Iron batteries are inherently safer for three reasons. They contain less energy per unit volume and weight, decompose at higher temperatures, and when they begin to decompose, they release less heat per gram of material.

The BYD Blade starts off on the right foot with iron-based chemistry and builds on it using a long, thin battery cell. That means that although the cells contain a lot of energy, any puncture or damage to the cell will damage fewer layers and will be able to dissipate heat more easily. This is why Blade cells can be pierced and not burst into flames. However, the battery packs are difficult to master, and despite the blade cells having thermal safety features, BYD's blade packs have caught fire. The only drawback I have against the Blade package from a safety perspective is that the cells are very close together, so there is little to slow the spread of thermal spread between the cells.

I assume there is thermal or fireproof insulation between cells because it is common, but I have no confirmation of that. With this in mind, the BYD package seems to be the winner here in terms of safety, but let's look at CATL and Tesla. Qilin uses shorter cells than the Blade pack, but they are also thicker and can trap more heat. What I'm not convinced about Qilin vs Blade is that the Qilin package has liquid between each row of cells instead of thermal insulation or fire retardant. Water can absorb a lot of heat, but it can also evaporate or run off, creating other hazards and inconsistencies.

With that in mind, I would rate the CATL based Qilin Iron pack a close second behind the Blade pack. The Nickel Qilin package is a completely different story. Large prismatic nickel batteries contain a large amount of volatile material and relatively little to contain that energy. CATL claims its Qilin package can cool cells quickly enough to mitigate thermal runaway. I think that might be the case with LFP cells, which heat up quite slowly, but not with nickel battery cells, which heat up and explode within a few seconds. With this in mind, I would rate the Nickel Qilin package fourth in terms of safety.

The Tesla package is also a high-nickel package, but it contains a number of safety features. The 4680 cells probably contain an overpressure mechanism at the bottom of the cells, the 4680 cells are smaller than a prismatic cell and therefore contain less energy, and the 4680 has a case that is 2 or 3 times larger thicker than a typical battery cell. As a side note, the bottom of Tesla battery packs are designed to melt and release the cells during a fire, making it easier for firefighters to control the fire. According to Munro's teardown, this appears to include the new 4680 battery. Elon Musk has said that safety is Tesla's number one priority, and it shows.

I spoke to Tesla engineers at the Giga Austin event and they confirmed that the new 4680 pack is safer than the previous 2170 packs despite using larger cells. However, it is still a volatile nickel-based package, meaning it will take third place behind iron packages. What about the cost? At the moment, the cost of nickel- and iron-based chemicals is similar even though iron-based cells use cheaper metals. In the past, iron-based cells were cheaper and I assume we will return to that market situation in the future. I'm not sure if that will be the case, but it may not matter because, as we will see, EV manufacturers may have to pay the price that the market will bear to third-party suppliers.

Additionally, I expect savings to be made in in-house production, rather than chemistry. As for assembly, the BYD blade pack appears to be the cheapest to manufacture. It is an iron-based cell sandwich with cooling plates at the bottom of the package. The cells are large, meaning fewer cells are required, meaning fewer electrical and mechanical connections. I don't know how much simpler it can be than that. The CATL Qilin package will be more expensive to assemble because it uses more cells, which means a higher number of parts and more connections. Additionally, there is cooling between each row of cells, and each cell in each row will probably need to be glued, blued, or screwed into place.

Let's compare that to the Tesla package before assigning a rating. The 4680 package uses up to 1000 cells, requiring a complex current collector. However, it uses minimal fasteners and instead fixes everything in place by pumping polyurethane foam into the backpack. Additionally, it only uses cooldown on every other row of cells, which reduces the part count compared to Qilin's cooldown. If that were the end, I'd say the Tesla 4680 pack assembly would be on par with the cost of the Qilin pack. However, I expect Tesla's pack to be cheaper to manufacture because the cells in the pack will be cheaper as long as Tesla can get their dry battery electrode process working.

That process will reduce the cost of cells by reducing energy use, capital cost and space. Additionally, Tesla cells use a tableless electrode and cylindrical cells are faster and easier to manufacture. All of that adds up to higher performance and lower cost for the cells, which of course reduces cost at the package level. With that in mind, I would give Tesla's nickel-based 4680 battery packs second position behind the BYD iron-based packs, followed by the iron-based Qilin packs and then the nickel-based Qilin packs. . When I take all of these variables into account using a 10-point system and average the scores, the battery packs are for the most part neck and neck.

The Tesla 4680 structural package takes first place with 9.0, BYD Blade second with 8.8, Qilin Iron third with 8.6, and Qilin Nickel fourth with 8.4. The Tesla package only takes the cake because it has no serious drawbacks. It is a good all-rounder. However, let's add another variable, scalability. Iron-based lithium-ion battery packs will dominate this decade because iron is more available. If we take that into account, then the BYD battery pack is ranked first, Qilin Iron and Tesla 4680 packs are ranked second, and Qilin Nickel is ranked third. But as we know, Tesla also plans to produce an iron-based 4680 battery cell. I'm sure you're also curious to know where the latest generation batteries are located.

With the additions to the table, everything remains the same relatively speaking, but the Tesla 4680 Iron battery pack sweeps the board and pushes all other cells down. Although an iron-based 4680 would have a high average score, it would have one major flaw: the energy density would be on par with the latest generation iron-based battery packs. However, Tesla should still be able to get a 300-mile range in the coming years due to improvements in chemistry and weight savings at the vehicle level thanks to its structural package and gigacastings. Let's go over the other assumptions behind some of these numbers because I haven't fully explained everything we see here.

Why do I show that the Iron 4680 package has slightly better cooling performance than the Nickel 4680? This is because iron cells have lower thermal requirements than nickel cells. That didn't happen with the Qilin pack because the cooling is already maxed out with nickel cells, so I also gave the iron cells a 10 out of 10. Next, some might think that I have underestimated the Qilin Nickel pack because of its high energy density, but energy density is not the top priority for automakers. Tesla could make a vehicle with a 600-mile range today with cutting-edge technology, but they don't because right now the game is about putting more vehicles on the road instead of fewer with longer range.

Next, notice that the latest generation packages perform significantly worse in most areas than the new generation packages. Even the package I rated the lowest, the Qilin Nickel package has better ratings than the older packages. There is clearly a generational improvement here. If you are an automaker with limited cells and packs, and they all are, I would be happy to get any of these battery packs. And, if neither of them were available, I would easily accept a next-generation package that uses transverse modules and bracing. That's clearly the case because that's what GM and Ford are doing. They are happy to take a 5-10% hit on battery pack range and cost if it means they can produce some EVs instead of none.

The same goes for Tesla. Tesla still uses 18x65mm cells, a form factor that debuted in 1994, in its fastest vehicle, the Model S. It uses a package with modules and transverse reinforcements. Why didn't I give Tesla extra points for scaling based on their battery lines producing 7x more cells than other cell lines? You can add points if you disagree with my perspective, which is that in the long term, battery production will be limited by raw materials, not battery factories. There is an overproduction of battery cells in operation and a growing shortage of materials to power those factories.

In the short term, the 4680 production system will allow Tesla to reach the bigger players more quickly and with fewer resources, but they will eventually run into a materials bottleneck like everyone else. The extent of that bottleneck depends on the execution of the third part of Tesla's Master Plan. What this all means is that instead of giving Tesla credit for both scaling and cost, I increased Tesla's score on fair cost, where they appear cheaper than comparable chemicals in next-generation package designs. Before moving on to the last chart, why didn't I take into account the vertical integration of BYD, CATL and Tesla and the ways that could affect their ability to scale?

It's a topic worth expanding on, but it's probably best to include it in a separate video because the situation is evolving rapidly due to Tesla's plans and geopolitical considerations. Suffice it to say that there would be no simple and definitive answer. The video would or will be more strategic and will involve many questions. However, along with vertical integration are shipping costs, profit margin, and taxes. They are worth mentioning in this video, which takes us to the final leaderboard. The leaderboardfinal is a slight remix of the last leaderboard. All I've done here is change the production cost perspective to Tesla's cost perspective.

Tesla won't be selling batteries to other automakers anytime soon, but BYD and CATL will sell batteries to Tesla. Tesla's in-house production will have minimal shipping costs, will not include a profit margin for a third party, and will have no associated tax cost. To account for that, I applied a fixed relative cost score of 6 to the BYD and CATL packages, regardless of chemistry. Because? Two reasons. First, I expect the cost savings Tesla realizes from in-house production to be much greater than any price difference between chemicals. In-house production will save Tesla 10% to 20% on shipping, margins and taxes. Additionally, Tesla hopes to be able to produce cells cheaper than anyone else, further increasing the difference between the costs of in-house and third-party cells.

Beyond that, market forces can also come into play. My opinion is that even if one company can produce cells cheaper than the others, regardless of the cost of nickel or iron material inputs, the market price will probably be similar for battery packs because it is a supply-constrained market. Of course, there will be some price variation between contracts, but in general I expect them to charge whatever price the market will bear. What this all means is that, from Tesla's perspective, the in-house 4680 battery packs will be significantly cheaper than any other option on the market. So while many people seem to see BYD and CATL as Tesla's competition, they are not.

It is a failure of logic. First of all, Tesla won't be selling batteries on the open market anytime soon. Second, no battery pack can compete with Tesla's internal costs. Third, despite the cost advantage of in-house production, demand for Tesla's battery cells will be so great that in-house production will not always be able to meet it. Tesla is such an efficient vehicle manufacturer that it can buy batteries from BYD and CATL at a premium, put them in its vehicles, and make a profit. They are suppliers, not competitors. In short, none of the next-generation battery packs significantly outperform each other, be it the BYD Blade battery pack, CATL Qilin or Tesla 4680.

But none of them are a failure either. They are all next-generation battery packs that live up to that designation. They are the next step forward in battery pack technology and have the potential to be better than the latest generation battery packs in almost every aspect. Of course, there are marketers, fans, and advertising merchants who can push the idea that one package is significantly better than the other. But, at least based on the information we have now, that is not the case. What I find most interesting is why the design of each package is so different. BYD and CATL's livelihood is still based on iron and will continue to be based on iron because iron is abundant and they need a highly scalable solution for the Chinese market.

But in addition to scalability, they are working to increase the range of vehicles for Chinese consumers, which means they need to use a prismatic format to maximize energy density. With the prismatic form factor chosen, the two best options for eliminating the transverse stiffeners were to replace them with structural cooling or convert the cells themselves to transverse stiffeners. Tesla is in a different boat. Their goal was to maximize production speed in a continuous moving process. This made a cylindrical battery cell the best choice because it is the easiest and cheapest cell form factor to manufacture. Additionally, they plan to use a variety of chemistries to support a wide range of use cases.

Iron-based battery cells simply aren't enough for the long-range Cybertruck and Semi, so Tesla will need to use high-energy nickel chemicals. High-energy nickel chemistries are best suited to a small form factor because it makes it easier to control thermal runaway. With the cylindrical form factor chosen, the best way to eliminate the cross braces was to use a compact honeycomb design fully bonded with polyurethane foam. If you twisted my arm, I'd say I prefer Tesla's approach because the 4680 structural package is a good all-rounder for both nickel- and iron-based chemistries. That makes sense because Tesla started with a blank sheet of paper and wanted to keep as many chemical options open in the future as possible.

I think it's the most future-proof package design, but that's just a hunch because the battery industry is evolving rapidly and it's hard to look more than 3-5 years ahead. The situation is complex for Tesla. Tesla is a newcomer and is tackling many new technologies at once, raising anxiety levels. And it doesn't help that, as I showed in the last video, Tesla is moving slower than expected. On the other hand, Tesla doesn't need to compete on the open market with its 4680 structural and cell package, which means that even if they don't meet the performance targets I show here in the short term, they will still be cheaper than anyone else. alternative that you can buy at BYD and CATL.

And that's not to mention that in-house manufacturing will give Tesla better control of its own destiny by allowing it to scale at will rather than being at the mercy of third-party suppliers. If you enjoyed this video, please consider supporting me on Patreon with the link at the end of the video or as a YouTube member. You can find the details in the description and I look forward to hearing from you.