The Beijing motor show featured a new electric-car battery from a Tesla supplier claiming a 1000km driving range. CATL, a Chinese company that provides batteries for Tesla and Volvo, introduced a new lithium iron phosphate (LFP) unit at the show, said to be capable of offering vehicles a driving range of up to 1000km on a single charge.
CATL, the world’s largest electric vehicle battery maker, currently supplies power units for Tesla, Ford, Volvo, and Polestar. LFP batteries are cheaper to produce than the nickel manganese cobalt units present in most electric cars, and can be charged to 100 per cent more frequently without damaging the cells. However, they are generally not as energy-dense, cannot charge as quickly, and do not perform as well in cold weather.
The ‘Shenxing Plus’ battery, revealed during the 2024 Beijing motor show, surpasses CATL’s existing Shenxing battery, which already claims up to 700km of driving range in certain vehicles.
The driving range target depends on the energy efficiency of the vehicle it is fitted to, and a battery capacity has not been disclosed. The new battery is said to improve energy density by 7 per cent compared to the previous generation battery and offers an energy density of 205Wh/kg.
For reference, a 77.4kWh battery in a Kia EV6 weighs around 475kg. Gao Huan, chief technical officer of CATL’s Chinese electric vehicle division, presented the Shenxing Plus battery at the Beijing motor show, stating that it can be recharged at a rate of “one kilometre [of range] per second” and can deliver a 600km estimated range in 10 minutes of charging.
In other news, LG Energy Solution (LGES) CEO Kim Dong-myeong announced that the company will commence Tesla 4680 battery production as early as August. LGES plans to start 4680 mass production at its Ochang factory in North Chungcheong Province and will also begin producing Tesla’s 4680 battery in North America once its new Arizona factory is constructed.
LGES will supply Tesla with 4680 battery cells and is in talks with other customers besides Tesla about 4680 battery supply. LGES is considering mass-producing the 4680 battery in China at its Nanjing factory.
Tesla is also enhancing its own 4680 production lines. In October 2023, Tesla announced that it built its 20 millionth 4680 battery cell at Gigafactory Texas. During the Q4 and Full Year 2023 earnings call, Elon Musk and another Tesla executive shared that 2024 would be a significant year for ramping 4680 production.
Elon Musk emphasized that Tesla also expects to ramp orders from its suppliers. During TSLA’s Q4 2023 and Full Year earnings call, a Tesla executive clarified that 4680 cell production would not limit the company’s Cybertruck ramp. Reuters reported in late December 2023 that Tesla’s 4680 battery cell was a major bottleneck to its Cybertruck production ramp.
According to the Tesla executive at the recent TSLA earnings call, the factory and engineering teams at Giga Texas were able to swap Line 1 from the Model Y’s cell design to the Cybertruck’s cell design, which is the battery cell with a 10% energy increase.
“We are currently operating one production line and one assembly line, using two assembly lines for yield and rate improvement trials. We have a fourth production line in commissioning, with plans to install four more starting in Q3 this year,” mentioned the executive from Tesla.
Elon Musk also mentioned that Tesla expects to increase orders from suppliers. At CES, President Allan Swan from Panasonic North America indicated that the battery supplier aims to boost annual production capacity by 2031. The expansion of Tesla Giga Nevada will also contribute to increased 4680 production.
Tesla has officially started the $3.6 billion expansion of Gigafactory Nevada, which will result in the addition of 4 million square feet of manufacturing space and two new facilities for Semi and 4680 cell production.
The project announcement was made nearly a year ago, on January 24, 2023. It is expected to create 6,500 new full-time jobs and produce enough 4680 cells for 2 million light-duty vehicles every year.
The company has been working on the early stages of permitting and other aspects, such as tax incentives, for which Tesla received $330 million.
A significant area of ground is already being excavated next to the main structure of Gigafactory Nevada, where one of the facilities, either for the Semi or 4680 cell lines, will be constructed.
This project will bring significant advancements to the Semi project, which has been progressing slowly. Tesla has delivered several units to Pepsi for local deliveries, allowing the company to assess efficiency and real-world performance.
Moreover, the 4680 project has mostly been behind schedule. Although Tesla has increased cell production, it has not reached the initially expected levels. Suppliers like Panasonic are expected to start producing the cell in the near future.
The original battery lug had only a small piece, but the 4680 battery adopts a full lug design, resulting in a significantly larger welding area. An increase in the welding area raises the likelihood of errors. If the welding machine outputs too much energy, the welding will penetrate the pole lug. If there’s insufficient energy, the welding will not be strong enough. In either case, the battery will be scrapped.
Tesla has not clearly defined the welding effect until this year. The company is innovating from the source, but they are uncertain about the implementation details, so they are investing in finding someone to help them realize their vision, as mentioned by an equipment supplier. Additionally, Tesla has encountered challenges related to yield, such as laser sealing.
By the end of last year, Tesla’s 4680 battery production yield was only 92%. Industry calculations suggest that the yield rate of 4680 batteries must exceed 95% to reduce costs and achieve commercial use.
The efficiency of Tesla’s production lines also falls short of industry expectations. An equipment manufacturer indicated that, at the beginning of this year, the production efficiency of Tesla’s 4680 battery was approximately 85 cells per minute. Previously, the industry believed that the upper limit of the efficiency of the 4680 battery was 350 cells per minute.
As Tesla’s production lines operate at higher speeds, quality control issues in the manufacturing process are likely to persist.
“At even a 0.001% miss of dust and debris, there can be a short circuit in the battery. The lab environment won’t magnify these subtle possibilities, but the factory will. You will discover new failure modes all the time,” said Tesla battery project leader Drew Baglino at the investor day in March this year.
Tesla’s 4680 battery manufacturing plan has not been finalized yet. “The issue is not just in production, but also in design modifications. Often, the next version has to be initiated before a process is completed,” explained a Tesla engineer.
According to estimates by industry experts, if dry electrodes are not insisted upon, the Tesla 4680 battery could reduce the cost of the Model Y by approximately 8%, equating to a 20% reduction in battery cost. Although this is less than half of Musk’s goal, it represents a significant achievement in the power battery industry. Achieving similar cost reductions would take Panasonic and CATL at least three years.
Tesla is committed to developing the dry electrode process, even if it means delaying the delivery of the Cybertruck and next-generation cars. Musk envisions that the 4680 battery will not only support Tesla’s current sales of 2 million vehicles per year, but also enable the future sales of 20 million vehicles per year.
Cheaper batteries are essential to support Tesla’s aim of creating a $25,000 affordable model. In March this year, Tesla completed model development and made a breakthrough in larger-scale one-piece die-casting technology. The 4680 battery was the final obstacle.
Within the automotive industry, only Tesla has the courage to build batteries in this way.
Based on industry insiders’ estimates, if dry electrodes are not insisted upon, the Tesla 4680 battery might still reduce the cost of the Model Y by about 8%, meaning a reduction of 20% in the battery cost. Although this is less than half of Musk’s goal, it remains a noteworthy accomplishment in the power battery industry. Achieving similar cost reductions would take Panasonic and CATL at least three years.
Tesla is steadfast in its commitment to developing the dry electrode process, even if it means postponing the delivery of the Cybertruck and next-generation cars. Musk envisions that the 4680 battery will not only support Tesla’s current sales of 2 million vehicles per year but also facilitate the future sales of 20 million vehicles per year.
Only more affordable batteries can help Tesla achieve its goal of developing a $25,000 economical model. In March this year, Tesla concluded model development and overcame larger-scale one-piece die-casting technology. The 4680 battery proved to be the final hurdle.
In the auto industry, only Tesla is willing to invest extensively in technology ahead of time and tie its business growth to technological breakthroughs. This strategy amplifies both the potential benefits and risks.
The past achievements and current challenges faced by Tesla are all rooted in a methodology based on first principles: rejecting conventional industry norms, questioning original requirements, and reimagining how things are done based on fundamental physics.
This approach is typically successful when Tesla seeks to challenge and defy old practices or habits developed in a particular technological era, especially when new technologies can overcome previous limitations. Musk astutely recognized that the constraints of the past were no longer valid, breaking through the perceived “impossibility” in the minds of industry experts and finding solutions.
This calls for technical intuition and judgment. However, it is challenging for Musk or any individual to objectively and comprehensively evaluate the overall technology and engineering level of an era.
In some cases, Musk’s ideas coincided with technical and engineering support; for instance, when he envisioned integrated die-casting from toy manufacturing, there happened to be a company capable of producing a 6,000-ton die-casting machine – Lijin.
Additionally, the 33-engine parallel propulsion solution used by SpaceX is an idea that was attempted by former Soviet scientists in the 1970s but failed. The interaction of rocket engines when pushing flow, and the need for real-time adjustment of engine settings presented a challenge. However, by 2023, when SpaceX implements this idea, computer computing power and algorithms will be capable of handling such complex tasks—the computing power of mainstream AI chips is now a billion times greater than it was 50 years ago.
In each of these examples, Musk went back to the drawing board and reexamined long-held conventions that had been unquestioningly accepted for years. In the well-established automobile and aerospace industries, major manufacturers consistently pursue peak production efficiency using established processes, making it challenging to think beyond existing practices.
The limitation of first principles is that they cannot overcome the constraints of the times. When Tesla’s objectives cannot be achieved with current technology, significant time and resources must be invested to make incremental progress.
Tesla faced a setback when mass-producing the Model 3 in 2017: Musk believed that robotic arms could entirely replace human labor, an inevitable development in manufacturing. However, he overestimated the level of automation technology. The robotic arms were unable to perform even simple wire bundling. This led Tesla into a production crisis, and Musk ultimately resolved the issue by calling workers back to the factory.
Battery manufacturing presents a similar challenge, involving multidisciplinary and complex tasks with interconnected processes. Musk initially viewed the step of “coating with wet positive and negative electrode materials and then drying them” as unnecessary. However, eliminating this step would necessitate an overhaul of the entire process, from mixing and coating to die-cutting and drying.
Even if Tesla can achieve this process in the lab, it must still address the interrelated challenges of mass production and commercialization. Producing one million electric vehicles requires over one billion cells, necessitating the repetition of the production process billions of times on the same equipment, achieving a specific yield target, and cost control.
Several experts in the industry anticipate that in 2025, Tesla will commence mass production of 4680 batteries, but the final mass-produced version is expected to have significantly reduced performance compared to the 2020 release. The current energy density of Tesla’s 4680 batteries stands at 265Wh/kg, nearly 20% lower than the industry’s projected 330Wh/kg. As a result, the Cybertruck, powered by this battery, has a maximum range of only 547 kilometers, falling well short of the initial target of 800 kilometers.
Since the introduction of the 4680 battery, Tesla has achieved only one-third of its original goal in three years. While Tesla has succeeded in mass-producing dry-process graphite anodes using a simpler process, the more challenging dry-process silicon anodes and cathodes still remain a hurdle.
From a competitive business standpoint, Tesla’s product development has been slow and at times unacceptable. The company’s product release schedules have been disrupted at a crucial time for pursuing success, causing delays in the production of new vehicles.
From a technological evolution perspective, Tesla has pioneered advancements in the industry with the standardized size of large cylindrical power batteries through the 4680 battery. Other battery giants like CATL have also started exploring the dry electrode process, extending this concept to battery diaphragms and other components. The 4680 battery may very well be driving a technological revolution in power battery manufacturing.
On June 26, reports surfaced indicating that Tesla is contemplating halting the production of 4680 batteries at its GigaTexas facility in Texas due to unsatisfactory energy density, charging performance, and higher costs. If cost reductions don’t meet expectations by the end of the year, Tesla will cease 4680 battery production and opt to source them from external suppliers instead.
Tesla introduced the 4680 cylindrical battery at Battery Day on September 22, 2020. It measures 80mm in height and 46mm in diameter, and promises a fivefold increase in energy density, a 16% boost in range, and a 14% reduction in cost compared to traditional lithium batteries.
The 4680 battery features a module-less design, reducing the complexity of battery thermal management by utilizing fewer cells. Additionally, its laser-welded tabless design lowers internal resistance while enhancing thermal stability.
A research report from China International Capital Corporation (CICC) suggests that as manufacturing processes improve and production lines stabilize, the yield rate of 4680 batteries is expected to steadily increase. This large cylindrical battery design is projected to gradually penetrate the offerings of other automakers, starting with Tesla. By 2025, the total installed capacity of 4680 and other large cylindrical batteries could surpass 180GWh, comprising approximately 12.2% of the total installed capacity of power batteries.
Continuous progress has been made in the mass production of 4680 cylindrical batteries since 2023:
– In January 2023, Tesla produced 1 million 4680 battery cells.
– In June 2023, Tesla produced 10 million 4680 battery cells.
– On October 11, 2023, the 20 millionth 4680 battery rolled off the production line at Tesla’s Texas factory.
– On June 6 this year, Tesla announced that its Gigafactory in Austin, Texas (GigaTexas) had produced 50 million 4680 batteries.
Over the past year, Tesla’s 4680 battery production has significantly increased, reaching a cumulative total of 40 million units, averaging nearly 1 million units per week.
In January this year, after Tesla released its Q4 2023 and full-year financial reports, CEO Elon Musk and executives addressed investor concerns regarding the 4680 battery. They mentioned that the 4680 cells are currently ramping up, with a few weeks’ worth of production inventory. New production and assembly lines are also being constructed. The year 2024 is expected to be a significant year for the growth of Tesla’s 4680 battery production capacity.
In April this year, Tesla updated the project’s progress while announcing its Q1 2024 financial results. Tesla’s Vice President of Vehicle Engineering, Lars Moravy, stated, “The production of 4680 batteries has increased by about 18% to 20% compared to Q4 last year, sufficient to meet the demand for Cybertruck, which has an annual demand of about 7GWh. It is expected that the second quarter will also continue to outpace Cybertruck’s capacity ramp-up speed. As capacity ramps up, with the improvement in production yield and increase in output, the unit manufacturing cost (COGS) is also rapidly decreasing.”
Why is Tesla considering abandoning the 4680 battery, given the growing production capacity?
Previously, media reported that as a central element of Tesla’s strategy to reduce manufacturing costs through technology, Elon Musk announced as early as 2020 that the 4680 battery could reduce battery costs by 50%, provided Tesla could overcome the challenges of dry electrode processing for both the cathode and anode.
However, the annual production capacity of 4680 batteries as of March this year was only enough to supply 60,000 Cybertrucks, and costs were higher than anticipated. Tesla was still unable to mass-produce dry electrodes.
At the start of this year, Tesla’s management established a clear evaluation standard: by the end of the year, the cost of Tesla’s in-house produced 4680 batteries must be lower than those of suppliers such as LG and Panasonic.
Despite this, in the nearly four years since the 4680 battery was introduced in 2020 and went into mass production at the end of 2023, companies like CATL and BYD have managed to decrease battery costs to RMB 0.4/Wh. Even if Tesla meets its cost reduction goal by the end of this year, according to numerous engineers and industry insiders, the cost of 4680 batteries may still be between RMB 0.8-1/Wh, which is twice that of CATL and BYD batteries. Furthermore, the safety, cycle life, and charging speed of this battery are inferior to mainstream batteries.
During Tesla’s 2024 shareholders meeting in June, Musk mentioned that the 4680 battery project is making steady progress and that every Cybertruck on the road is already equipped with 4680 batteries. However, he also acknowledged that the 4680 battery project is facing significant challenges.
Under pressure, Tesla is also exploring the possibility of procuring more batteries from external suppliers, particularly Chinese companies.
Previously, it was reported that starting from the second half of 2023, Tesla began purchasing positive electrode rolls (components of battery cells) from two second-tier Chinese battery companies and transporting them to its Texas factory to produce 4680 batteries. These two companies were selected by Tesla after evaluating several cylindrical battery production lines of Chinese power battery companies last year. Positive electrode rolls make up about 35% of the total cost of the cell. This practice of buying electrode rolls from China and then manufacturing batteries may continue until the third quarter of this year.
A source close to Tesla mentioned that Panasonic, Tesla’s battery supplier, will only begin mass-producing 4680 batteries in the third quarter of this year.
In March this year, foreign media reported that Tesla was searching for materials suppliers in China and South Korea to help reduce the cost and improve the energy density of its latest 4680 battery. Meanwhile, the company was working on resolving performance and production issues associated with the 4680 battery, which had previously delayed the launch of the Cybertruck.
It is said that Tesla has sought collaboration with Chinese companies Ningbo Ronbay New Energy Technology Co., Ltd., and Suzhou Dongshan Precision Manufacturing Co., Ltd. to help reduce material costs. Currently, Tesla is increasing the production of 4680 batteries.
If Tesla can address the performance and process issues of the 4680 battery and achieve its ambitious production goals, the 4680 battery could ultimately be crucial to Musk’s aim of producing 20 million cars annually by 2030.
In summary, many Chinese battery companies, including CATL, BAK Battery, EVE Energy, CALB, and REPT, are all involved in the development of 4680 batteries. It is anticipated that more Chinese companies will be added to Tesla’s list of battery suppliers in the future.
Tesla has been rumored to abandon 4680 cell production and rely on third-party suppliers if it cannot cost-effectively produce the larger cells. A new report from Korea indicates that local battery manufacturers are prepared to mass produce cylindrical cells with a 46 mm diameter, apparently confirming previous rumors.
The Tesla Model Y lithium-ion cell has been a widely discussed battery in the industry since Tesla introduced the concept in May 2020. When it was first launched, mass production of the Model Y cell seemed far off, but now, Tesla is already selling vehicles equipped with this innovative technology for the mass market. The Model Y cell’s concept is expected to have a significant impact on the future of energy storage, both within and outside of the transportation sector. According to Musk, this technology is “far more important than it sounds”.
In this blog post, we delve into the advantages of larger format cells and explain why bigger isn’t always better. We share insights about the Tesla Model Y cell using data from the About:Energy lab, which was obtained from cells extracted during the Sandy Munro Model Y teardown in 2022.
Key Points
– The Tesla Model Y cell can store 5 times the energy of most 21700 cells, but this doesn’t result in a higher gravimetric energy density at the cell level.
– The ‘tabless’ design of the Tesla Model Y cell means it has low resistance, allowing it to charge and discharge at the rates necessary for automotive applications.
– The ‘tabless’ design also holds promise for thermal management, potentially reducing the complexity of the thermal management system, promoting more uniform operation, and leading to longer-lasting, safer cells.
Cylindrical Cell Advancements
The Model Y cell represents the next stage of the cylindrical lithium-ion cell. We started with 18650s (18 mm diameter, 65 mm in length), then transitioned to 21700s (21 mm diameter, 70 mm in length). Now, we have a much larger 46 mm diameter and 80 mm length cell, known as the ‘4680’ form factor. The shift to larger format cells is driven by the need for increased cell energy density and enhanced pack efficiency. Following Tesla’s announcement of larger cylindrical cells, other manufacturers like BMW have revealed EV platforms designed using this cell type. Cell manufacturers and material developers such as Samsung, Panasonic, OneD, Echion, and others have also adopted the 46XX format.
Despite the promised benefits of this new cell type, it has yet to make a significant impact on the industry. Tesla has faced delays and suboptimal performance with early prototypes in scaling up its manufacturing. While production delays are common in the industry, surmounting technological barriers comes with challenges. Nevertheless, Tesla’s engineering teams recently achieved a milestone of 10,000,000 cells, equivalent to 0.85 GWh.
Cylindrical lithium-ion cells in the current format suffer from uneven current distribution, leading to temperature gradients that hinder the cell’s usable energy, resulting in significant energy loss as waste heat. Thicker cells, as proposed by Tesla, would normally pose challenges due to a decreased surface area-to-volume ratio. However, the ‘tabless’ design of the Tesla cells seems to overcome this issue. Base cooling is being suggested within these battery packs, making a wider cell diameter feasible when combined with the tabless design. It is anticipated that this cell will operate with a minimal temperature gradient across its volume, as compared to other cylindrical cells lacking the tabless electrodes.
Benefits at the Cell Level
The increase in cell volume translates to a higher energy storage capacity. We have observed that the Model Y cell can store 86.7 Wh of energy, 5 times more than Tesla’s most recent 21700 format cell, which stores 17.28 Wh. This results in a reduction in the number of cells needed in an electric vehicle battery. Assuming an 80 kWh benchmark battery pack size (e.g. Tesla Model 3), you would require 4630 cells of 21700 format, or just 923 cells of 4680 format. This is all very intriguing, but what does it mean?
At the cell level, the ratio of active material could be slightly increased due to having more active material within a single container (the ‘can’). However, we haven’t calculated any exceptional performance figures for the cell-level gravimetric energy density. In fact, the gravimetric energy density of the Model Y cell, standing at 244.0 Wh/kg, is lower than that of the Panasonic 21700 cell used in the Tesla Model 3 (253 Wh/kg).
This modest decrease is attributed to the larger, heavier auxiliary safety components, and it’s important to consider that the tabless design (and consequently manufacturing) is still in an early stage compared to the more mature Panasonic 21700 technology. We expect further enhancements in cell-level energy density before mass production begins in September 2024.
Below, we’ve included some examples of gravimetric energy densities from other cell manufacturers. However, direct comparison of gravimetric energy densities is oversimplified, and other factors such as power capability and temperature dependence must also be considered (for instance, we’ve observed a significant drop in accessible capacity of the LG M50LT at low temperatures, and it generates a substantial amount of heat during charge phases).
So, what is the fuss about the Model Y cell? The true advantage lies within the cells and originates from the improved manufacturing capability.
Conventional 21700 cells (including all Tesla cells) have small tabs that connect their electrodes to the terminals of the cell. In the images below, we present our analysis of the LG M50LT cell; the positive and negative tabs are visible in each image. Electrons flow through these tabs to transfer energy into the cell during charging or out of the cell during discharging. The size of these tabs has historically restricted the size of the cell’s jelly roll due to the high resistance of the small tabs.
High current flow density results in significant energy loss in the form of heat. Various comprehensive academic studies have highlighted the drawbacks of this design feature, particularly regarding potentially hazardous high temperatures reached during rapid charging. Consequently, the design of the cell is limited in terms of the jelly-roll volume, explaining why we have not seen cells larger than the 21700 in automotive or other highly rate-capable applications before.
The logical improvement in design is to enlarge the tab size to enable an increase in the size of the jelly roll. Although this sounds simple, it is very challenging to achieve. The welding process, which ensures good electrical contact between the tabs and the cell’s terminals, is the limiting factor – more details can be found here.
Tesla has addressed this issue by creating and patenting the ‘Cell with a Tabless Electrode,’ which essentially consists of an electrode with a single tab covering its entire end. This marks a significant advancement in the development of cylindrical lithium-ion cells, as demonstrated by the substantial increase in energy storage capacity referred to earlier. This tabless electrode will significantly reduce the internal resistance of the cell, allowing for higher-rate charges and discharges, as well as lower losses (less heat generation). Additionally, the tab also serves as an effective thermal pathway, benefiting from the tabless design and enabling the thermal management system of an EV to operate optimally.
We anticipate that this cell design will dominate the market, surpassing the existing technology. For this reason, we made every effort to obtain the Model Y cells to parameterize them, enabling our Voltt subscribers to begin designing their systems based on what we believe is the future of battery technology.
The 4680 would not be functional without the tabless electrodes – this component is crucial for the low cell resistance required to charge and discharge the cell at the rates necessary for automotive applications. Upon examining the data, the result is a performance comparable to the best 21700 cells currently on the market, but achieved in a much larger package. Tesla’s marketing has emphasized the significance of this for increasing the gravimetric energy density of the battery pack, with fewer auxiliary components around the battery pack and reduced complexity in the thermal management system being key drivers.
The entire cell manufacturing industry will undoubtedly strive to follow this trend to facilitate the simplification of battery pack design. This is an exciting development – engineering higher energy density into the battery packs, rather than waiting for new chemistry compositions to filter down from the electrochemists! Tesla appears to be moving faster than others in the industry in establishing a close connection between designing cells and constructing battery packs.
In fact, it is essential for cell design to be in a continuous loop with pack design, not only to extract the last bit of energy remaining in the battery for a given application but also to optimize the design for manufacturing, thereby maximizing the production cost efficiency of each battery. For the Model Y cell, we view this as a significant step toward enhanced thermal management at the battery pack level. This will lead to reduced thermal management design complexity, consistent operation, and safer, longer-lasting battery packs.
