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Fujifilm Prescale - Heat Sealing for Lithium Ion Batteries

Lithium ion battery
To check the balance of the heat bar when bonding aluminium laminate films used in the manufacture of lithium polymer batteries
When sealing gelatinous electrolytes inside lithium polymer batteries, an aluminium laminate film affixed to the casing exterior using heat bars that apply both pressure and heat. If the heat bar is improperly balanced during the bonding process, defective adhesion of the aluminium film may result, causing electrolyte leakage and personal injury risks. Therefore, checking heat bar balances is necessary when performing set-up of the heat sealing equipment.
Product used: Prescale (Ultra Super Low Pressure LLLW, Super Low Pressure LLW)
After the gelatinous electrolyte is injected into the casing, pressure and heat is applied to the aluminium laminate film using heat bars to seal the casing. However, before the assembly line begins operation, a Prescale film is inserted between the heat bar and its base plate where heat/pressure is applied. The Prescale film pressure test result is compared to a standardized sample to determine the heat bar pressure balance. When the Prescale test result indicates the pressure balance is unacceptable for achieving the desired seal, the heat bar is adjusted. The pressure test is then repeated until the acceptable standard is achieved.
Pressure is unevenly applied.
Pressure is high on the upper side.
The heat bar is parallel and pressure adjustment is optimal.
As seal quality improves, defects caused by improper pressure mounting during the heat sealing and pressure mounting process of aluminium laminate films are reduced.

Standardized adjustment and settings of heat sealing and the pressure mounting equipment is achievable, significantly reducing line operator set-up time.

Correlation of Prescale results with corrective actions taken by operators, maintenance teams or quality control assists in resolving heat sealing defects.

Without using Prescale
There is an increased probability of defective adhesion when the heat bar pressure balance is not checked and/or adjusted.
Using Prescale
The pressure balance can be quickly optimized and quality improved.