To fully understand the advantages of Enovix’ unique architecture, it’s important to first understand how a conventional lithium-ion battery works.
Long anode, cathode and separator strips are either stacked vertically or wound together.
Cells are packaged in an aluminized polymer pouch, and the pouch is filled with electrolyte - an organic liquid through which the lithium ions travel back and forth between the cell’s anode and cathode.
During charging, the lithium ions move from the cathode - the positive electrode - flow through pores in the separator - and into the anode, the negative electrode.
This process is reversed when the cell is discharged.
This basic principle is true for all lithium-ion batteries, and in this sense, the Enovix cell is no different.
What makes Enovix batteries different and capable of utilizing a 100% active silicon anode is their horizontally stacked and constrained architecture.
Rolls of cathode, anode and separator are precisely laser patterned.
After patterning, the material is stacked side by side in the familiar order of cathode, separator, anode, and separator, until the stack equals the specified width of the cell. This allows for more efficient use of the batteries volume which improves its overall energy density.
Next, the constraint is applied to the stack, welded, and the alignment tabs are removed.
Once the cell is free from its alignment jig, the cathode and anode busbars are inserted, trimmed and formed into final tabs.
Throughout every step of this process, inline metrology ensures the highest quality and specifications are met.
Finally, the cell moves to packaging. From this point on, the Enovix manufacturing process is similar to other conventional battery manufacturers.
The cell is pouched, and filled with electrolyte. From here it moves to final testing and quality control before being boxed and shipped to customers.
A conventional lithium-ion battery can’t practically accommodate a 100% active silicon anode because they expand significantly during charging - creating high pressure within the battery.
This pressure acts on the large face of the battery and would require a constraining force as large as 1.7 tons to keep the silicon anode from expanding.*
Enovix’ horizontally stacked architecture can accommodate a 100% active silicon anode, only requiring our unique and patented constraint system to contain 210 pounds of force.
This is how Enovix is able to harness the high energy density of silicon while providing a robust, best-in-class energy source that doesn’t compromise safety, to power tomorrow’s devices today.
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* Based on a 50mm x 30mm x 3mm sized cell