Key Takeaways
1. Tesla plans to use its own 4680 batteries in the 2026 Model Y after previous issues with energy density and repairability.
2. The company is shifting focus to improve the 4680 battery’s performance and has faced challenges with low sales of the Cybertruck.
3. Tesla aims to produce 4680 batteries more cheaply using a dry electrode method, but they still have thermal inefficiency compared to Panasonic’s 2170 cells.
4. The new approach allows for individual cell repairs by integrating 4680 cells into non-structural battery packs, improving repairability.
5. Specific Model Y versions equipped with 4680 batteries are yet to be announced, raising curiosity about their charging performance.
Tesla is once again planning to use its own 4680 batteries in the 2026 Model Y. The first attempt at this didn’t go very well, as the initial structural battery pack that was integrated into the chassis was not able to be repaired. Additionally, the first generation of 4680 batteries had low energy density and a poor charging curve.
New Developments
Due to these issues, Tesla decided against using 4680 cells in the Model Y and instead focused on creating a second version of the battery that would have better energy density for the Cybertruck. However, the electric pickup hasn’t been selling well, leaving Tesla in a tough spot. They even had to stop production on two of their other premium models, the S and X, which saw a 50% drop in sales in 2025.
Elon Musk hinted during the Q4 earnings call that the Cybertruck might be remodeled as an autonomous vehicle for work. Meanwhile, Tesla might have enough production capacity for the 4680 batteries, made using the more affordable dry electrode method, to begin fitting “some Model Ys with our 4680 cells.” The company blames supply chain issues due to tariffs for this change.
Performance Concerns
While Tesla may be able to produce the 4680 batteries more cheaply now, they still suffer from thermal inefficiency and a less favorable charging curve compared to Panasonic’s 2170 cells. This could leave potential buyers feeling uncertain about the news of the 4680 batteries returning to the Model Y lineup.
On the bright side, there are some positives regarding the switch back to Tesla’s own 4680 cells, even if they are not as good as the 2170 packs in long-range Model Y versions. According to Tesla’s CFO, their engineers are working on resolving supply issues by incorporating 4680 cells into non-structural battery packs.
Repairability Improvement
This means that Tesla is now placing 4680 cells into the trays of the 2170 pack housing, which could allow for repairs by replacing only the individual cells that fail. Earlier, Tesla utilized a cell-to-pack method where the large 4680 battery was part of the Model Y’s structure, using a large amount of adhesive that made it impossible to remove individual cells. This setup meant that the entire battery would need to be replaced once it failed.
Tesla hasn’t disclosed which specific versions of the Model Y will come equipped with 4680 batteries, but curious customers will find out shortly and will likely test the charging curve to see if Tesla has remedied the previous charging speed problems seen in the Cybertruck and the first generation of Model Y 4680 cells.
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