The 4680 battery significantly improves power output, optimizes heat dissipation, production efficiency, and charging speed through changes in the tab structure.
Traditional batteries have only two tabs, connecting the positive and negative electrodes, while the 4680 battery features full tabs (directly cut from the positive/negative electrodes), which greatly increases the current path and shortens the distance between the tabs, resulting in a significant boost in battery power.
Increased Output Power: The battery's current path is widened, and internal resistance is significantly reduced, which decreases internal losses and greatly enhances battery power (up to 6 times that of the 2170 battery).
Improved Safety: Unlike prismatic batteries, cylindrical batteries primarily dissipate heat axially, with heat exiting through the tabs. Traditional cylindrical batteries like the 2170 have only two tabs, resulting in a narrow heat transfer channel and poor heat dissipation. The 4680 battery has a significantly larger tab area, providing a wider heat transfer path, greatly improving heat dissipation efficiency (to only 20% of traditional cylindrical batteries), and enhancing thermal stability.
Significant Improvement in Fast Charging Performance: With the full tab structure, electrons move more easily within the battery, increasing the current rate, which in turn allows faster charge and discharge speeds.
Improved Production Efficiency: The elimination of the process and time required to add tabs on the production line saves equipment space and reduces the potential for manufacturing defects.
In simple terms, this refers to the process of folding the tabs together. Currently, there are three methods: pressing the tabs, cutting and stacking the tabs, and multi-tabs:
Pressed Tabs: The shape of the tabs is uncontrolled, which can easily lead to short circuits. During manufacturing, the two sections are sealed, and the electrolyte infiltration causes significant obstruction.
Cut and Stacked Tabs (Tesla): The tabs are cut at an angle and rolled, which is better than random extrusion and occupies less space. However, the surface has greater unevenness, and during manufacturing, the two sections are still sealed, which prevents continuous electrolyte filling.
Multi-Tabs: It is difficult to fold them neatly, and any misalignment in the tab positioning, especially at the outer edges, is easily magnified.
The welding process changes from point welding (used in traditional two-tab batteries) to surface welding (used in the 4680 battery with full tabs). This increases both the welding process and the amount of welding required. It is difficult to control the laser intensity and focal length, which can lead to either welding through and damaging the internal cell or incomplete welding. Currently, the battery yield rate is relatively low (92%).
Advantages
The electron movement path is shortened by 5%-20%, thereby reducing internal resistance by 5-20 times.
Significantly reduces electron migration and overvoltage phenomena, improving battery lifespan.
The contact area between the conductive coating and the battery shell reaches 100%, dispersing the heat generation area.
Disadvantages
The specific arc shape of the full tab requires higher precision from the cutting and punching equipment.
The requirements for laser die-cutting processes are higher; uneven cutting edges can cause gaps between the material layers, affecting the fit.
The number of laser welding points for full tabs is more than five times higher compared to the 21700 battery.
With the transition from pulse laser point welding in the 2170 battery to line or laser matrix welding in the 4680 battery, the laser welding process has improved. This may involve shifting from pulse lasers to continuous lasers, which would increase the overall production cost.
Contact Person: Miss. Kiki
| WhatsApp : | +8617763224709 |
|---|---|
| Skype : | +8617763224709 |
| WeChat : | +8617763224709 |
| Email : | kiki@lifepo4-battery.com |
