Closed Loop Micro Reference Sensing for Low Temperature Fast Charging
Closed loop micro reference sensing measures anode potential directly to eliminate sub-zero lithium plating during fast charging without compromising cell life.
Jellyroll Insertion
Meaning
Mechanical assembly stages place the wound electrode assembly into the cylindrical or prismatic casing. Automated tools perform jellyroll insertion to ensure that the fragile layers of anode, cathode, electrolyte and separator remain aligned. It is a foundational step in the cell production line that determines the final volume of active material.
Placement Accuracy
Precise alignment prevents the edge of the electrode from contacting the can wall. During the process of jellyroll insertion, vacuum grippers or mechanical mandrels guide the roll into the opening with sub millimeter clearance. Any misalignment can tear the separator.
Structural Integrity
The fit between the roll and the container must be tight enough to prevent movement during vibration. Proper jellyroll insertion ensures that the tab connections are accessible for the subsequent welding steps. It maintains the geometric stability of the internal components throughout the life of the battery.
Manufacturing Constraint
Speed and force are the primary variables managed by the production controllers. High speed jellyroll insertion requires specialized coatings on the separator to reduce friction and prevent static buildup. If the roll is compressed too hard, the porosity of the electrodes changes, which impacts the rate at which the battery can charge and discharge.
This physical restriction limits the maximum throughput of the assembly line to prevent yielding the active materials.