Hi friend! Let‘s take an in-depth look to understand the differences between Tesla‘s 2170 and 4680 battery cells. These lithium-ion batteries power Tesla‘s electric vehicles – but each has their own advantages and disadvantages. Read on as I, a battery technology enthusiast, share key details about Tesla‘s battery evolution to help highlight what sets the 2170 and 4680 apart.
The Role of Batteries in Tesla Vehicles
The battery pack is the most important and expensive component in any electric vehicle. For a company like Tesla that produces hundreds of thousands of electric cars annually, the batteries make up 25-40% of total vehicle cost according to experts. That means picking the right battery cell is critical.
The battery directly impacts 3 key factors for EV success:
Driving Range: More battery capacity allows higher range per charge. Long range alleviates driver "range anxiety".
Performance: Batteries supply power and torque to the motors. Better batteries mean faster acceleration.
Charging Speed: Faster charging requires batteries that can absorb high charge rates without damage.
Additionally, the battery design affects safety, lifespan, weight, sustainability, and manufacturing complexity. With such an important component, you can see why Tesla pours extensive R&D into improving their batteries.
The 2170 and 4680 represent Tesla‘s two most significant lithium-ion battery cell designs. Let‘s look at each in more detail…
Inside Tesla‘s 2170 Battery Cell
Tesla first used off-the-shelf 18650 battery cells purchased from Panasonic when launching the Roadster and Model S. However, when developing the Model 3 Tesla wanted to customize the cells more specifically for electric vehicles.
Thus, the 2170 battery cell was born in 2017. The 2170 refers to its dimensions – 21mm diameter and 70mm height. Here are some key facts on the 2170 cell:
- Produced by Panasonic at Gigafactory Nevada in a joint venture with Tesla
- Used in Tesla‘s Model 3, Model Y, and energy storage products
- Capacity of around 4.8Ah (or mAh) per cell
- Higher energy density than 18650 cells
- Enables over 300 miles of range in Long Range variants
- Lower cobalt content than previous Tesla cells
- Over 7 billion cells produced by end of 2021
Tesla‘s partnership with Panasonic has been critical for high-volume production of the 2170 cells. And Tesla is continuously working to improve the cell chemistry – increasing nickel content while reducing expensive cobalt.
Inside the 2170 Cell
Each 2170 cylinder contains the following key components:
- Cathode and anode electrodes
- Porous separator between electrodes
- Electrolyte to allow lithium ions to move
- Copper and aluminum current collectors
- External steel cylindrical case
The cathode is nickel-rich lithium nickel cobalt aluminum oxide (NCA), while the anode is made of graphite. 2170 cells also contain safety mechanisms like vents and shutdown separators to prevent thermal runaway.
Producing vast quantities of battery cells is an intricate process requiring precision automation. Here are some key steps Panasonic uses to make Tesla 2170 cells:
- Mixing of cathode and anode slurries
- Coating electrodes on thin foils
- Calendering to density and align particles
- Slitting foils into correct widths
- Winding electrodes with separator into a jelly roll
- Inserting jelly roll into steel cylinder case
- Sealing case and filling with electrolyte
- Initial charge/discharge formation cycling
- Testing samples from production lines
- Packaging and shipping finished cells
Carefully controlling each production step is crucial to ensuring consistent quality and longevity of the cells coming off production lines.
Evolution of Tesla‘s 2170 Cell
While first introduced in 2017, Tesla continues optimizing its 2170 battery cells today. For example, the energy density of 2170 cells improved from about 245 Wh/kg initially to over 300 Wh/kg by 2021 according to teardown experts Munro & Associates.
Tesla also reported reducing cobalt content of its cathode by 60% in several years. Lower cobalt improves stability and reduces cost. Ongoing R&D will likely boost performance and lower cost further.
But there is a limit to how much more can be improved with the 2170 format. That led Tesla to develop its next-gen 4680 cell.
Introducing The Tesla 4680 Battery Cell
In September 2020 at Tesla‘s Battery Day event, Elon Musk unveiled the company‘s new 4680 battery cell:
The 4680 cell draws its name from its dimensions – 46 mm wide and 80 mm tall. That‘s more than 5 times larger than the 2170 cell by volume.
Here are some key 4680 battery specs and details:
- Designed and produced in-house by Tesla at Kato Road facility
- Much higher capacity at around 9Ah (9000 mAh) per cell
- Tabless electrode design removes metal tab
- Around 5x more energy density vs 2170 cells
- Enables up to 16% more range from same battery pack size
- Structural pack integrated into vehicle frame
- Simplified manufacturing process with lower cost
- Currently only used in some Model Ys from Gigafactory Texas
The 4680 battery aims to provide step-change improvements in performance, range, manufacturing, and cost savings versus Tesla‘s 2170 cell.
New Manufacturing Process
In addition to the cell redesign, Tesla engineered a streamlined factory production system for the 4680:
- Directly coat active material onto battery foils rather than use electrode sheets
- Simpler and eliminates steps
- Dry electrode process instead of traditional wet slurry method
- Faster, more precise, and lower cost
- Integrated production from raw materials straight to finished battery pack
- Drastically reduces complexity
By optimizing each production step, Tesla aims to produce 4680 cells at lower cost while delivering higher performance.
Advantages of 4680 Cells
Let‘s compare the 4680 battery‘s benefits and drawbacks compared to the 2170 cell:
- 5x more energy density enables longer range
- More power and faster charging
- Tabless design improves thermal performance
- Structural pack lowers weight and cost
- Simplified manufacturing and lower $/kWh
- Designed to easily integrate into any Tesla vehicle
- New technology with limited production experience so far
- Energy density not yet as high as initial target
- Structural packs difficult to retrofit into older models
- Lower energy savings from reuse versus cylindrical cells
The 4680 promises big leaps in battery performance and manufacturing efficiency. As production scales up, the disadvantages should diminish over time.
Cost Savings Analysis
Tesla projected the 4680 cell would enable radical cost reductions versus its 2170 cells:
- 14% savings from optimized cathode/anode materials
- 7% savings from increased production efficiency
- 12% savings from simplified manufacturing process
- 3% savings from removing tabs and direct coating
Altogether, Tesla estimated 56% lower $/kWh for 4680 cells at scale versus 2170 production costs. Those savings can directly reduce the price of Tesla‘s vehicles while increasing profit margins.
However, third-party analysts project closer to 35-40% cost reduction versus 2170 cells as more realistic. Either way, the 4680 unlocks major advances and cost competitiveness.
Comparing 2170 vs 4680 Battery Cells
Now that we‘ve looked closely at each battery type, let‘s directly compare the Tesla 2170 and 4680 cells across key metrics:
A few things stand out from this comparison:
The 4680 battery cell has clear advantages in density, power, manufacturing simplicity, and cost savings
But the well-proven 2170 cell is produced reliably at vast scale today
For drivers, 4680 should deliver longer range and faster charging
While still early in the ramp up, 4680 is clearly Tesla‘s battery of the future
As Elon Musk stated, the 4680 battery represents a "massive breakthrough" for electric vehicles. But scaling 4680 production won‘t happen overnight. The 2170 will continue powering Models 3 and Y for years during the transition.
When Will 4680 Cells Be Ready?
Tesla initially planned to begin high-volume 4680 cell production in 2021 and integrate them into vehicles shortly after. However, undisclosed manufacturing challenges have delayed the 4680 ramp up significantly.
As of late 2022, here is the status of 4680 production and vehicle integration:
- Tesla produced over 200,000 4680 cells at Kato Road pilot facility in 2021
- Added two more production lines in early 2022 to supply Gigafactory Texas
- Only Model Y Performance versions from Giga Texas use 4680 structural packs currently
- Model Y 4680 pack has just under 100 cells versus 393 cells in 2170 pack
- Annualized 4680 production rate estimated around 30-50 GWh based on insider reports
Tesla aims to rapidly grow 4680 output over 2023 and beyond:
- Targeting annual production capacity of 100 GWh by end of 2023
- Adding more production capacity at Kato Road and Giga Texas
- Panasonic to supply 4680 cells from their Waco, Texas factory starting 2023
- Goal to switch all vehicles to 4680 cells within next 2-3 years
While slower than first projected, Tesla does appear to be making measured progress on scaling 4680 cell production. As output grows, expect to see 4680 batteries integrated into more Model Ys and eventually Model 3 and Cybertruck down the road.
The Future of Tesla‘s Batteries
Tesla has invested heavily in next-gen battery R&D, propelling them far ahead of other automakers. Here‘s what I expect to see from Tesla batteries in the coming years:
4680 cell cost reductions: Continued engineering and scale production will lower $/kWh over time.
New chemistries: Tesla will introduce LFP cathode 4680 cells where energy density isn‘t as critical. Also working on higher nickel cathodes.
Range boosts: 500+ mile range for top models likely achievable within 5 years.
Faster charging: Acceleration of charging speeds to 15+ miles per minute via cell improvements.
Vehicular integration: Structural 4680 packs rolled out across all models for efficiency and manufacturing simplicity.
Sustainability: Recycling and recovery processes to reutilize battery materials and minimize waste.
Solid-state batteries: Prototypes show huge promise. Commercialization expected in 2nd half of decade.
Tesla‘s unrivaled battery know-how will continue providing substantial competitive advantages as they work to realize their mission. Exciting innovations still lie ahead!
The Key Role of Batteries at Tesla
It‘s clear that batteries are absolutely vital to Tesla‘s vehicles. The 2170 cell enabled Tesla‘s success over the past 5+ years powering Models 3 and Y. While not perfect, it provided a balance of proven production scale and performance.
The 4680 battery stands to unlock the next level for Tesla‘s EVs. Its 5-6x leaps in density, power, and manufacturing efficiency ultimately aim to make Tesla‘s products better and more affordable. Integrating 4680s across the vehicle lineup will be a complex process during the transition away from 2170 cells however.
Despite early challenges ramping up 4680 production, I‘m confident Tesla‘s incredible engineering team will iron out the kinks over time. The 4680 battery remains one of the most important pieces as Tesla charts the future of sustainable transportation. I look forward to seeing these cells power Tesla‘s vehicles to bold new heights in the years ahead!
Hope you enjoyed learning about Tesla‘s evolving battery technology as much as I did researching and sharing these insights with you. Let me know if you have any other EV topics you‘d like me to cover in a future post!