Segmented Sealing Bar Heating for Uniform Pouch Foil Sealing
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Solution Overview
Problem
The existing heater structures for secondary battery pouch foil sealing processes suffer from non-uniform heating due to uneven heat distribution and pressure, leading to potential poor sealing quality.
Innovation Solution
A heater with a sealing bar equipped with multiple sub-heating units and a common heating unit, temperature sensing units, and a control unit to maintain uniform temperature across the sealing bar, ensuring precise temperature control and uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single heater block with one heater is used for sealing, then the structure is simple, but the temperature distribution becomes non-uniform leading to poor sealing quality
Solution Approach 1:
The heater block is divided into multiple independent heating zones (first heating zone, second heating zone, third heating zone) along the longitudinal direction. Each zone has its own heater coil and temperature control, allowing independent temperature adjustment to achieve uniform sealing across different positions of the pouch foil.
Solution Approach 2:
Different regions of the heater block are equipped with different heating capacities and control strategies. The first heating zone (with larger exposed surface area) receives higher heating power to compensate for greater heat loss, while the second heating zone (with smaller exposed surface area) receives lower heating power. This local differentiation ensures uniform temperature distribution across the sealing surface.
2Temperature
If the heater block has large exposed surface area to air, then heat dissipation occurs leading to temperature non-uniformity, but reducing exposed surface area limits the sealing zone
Solution Approach 1:
The heating power parameter is adjusted differently for different heating zones based on their exposed surface area. The first heating zone with larger exposed area is supplied with higher power (first heating power) to compensate for heat loss, while the second heating zone with smaller exposed area is supplied with lower power (second heating power). This parameter differentiation maintains temperature uniformity across the entire sealing zone.
3Force
If the cylinder applies pressure to the heater block, then sealing force is provided, but non-uniform pressure distribution causes non-uniform heat transfer
Solution Approach 1:
The sealing bar is divided into multiple sections corresponding to different heating zones, with each section independently applying pressure to the pouch foil. The cylinder applies force that is distributed through these segmented sections, ensuring uniform pressure distribution across the entire sealing surface, which in turn ensures uniform heat transfer from each heating zone to the pouch foil.
4Area of stationary object
If the heater coil is elongated from one side, then it provides heating coverage, but resistance increases with distance from supply side causing non-uniform heat generation
Solution Approach 1:
Instead of using one long heater coil from one side, the heating system is segmented into multiple independent heater coils (first heater coil, second heater coil, third heater coil), each serving a specific heating zone. Each coil has its own temperature control, eliminating the cumulative resistance problem of a single long coil and ensuring uniform heat generation across the entire heating area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures consistent sealing quality by independently controlling heat distribution along the sealing bar, minimizing heat loss and maintaining uniform temperature, thus preventing poor sealing.
Implementation Method 1
the amount of heat transferring from the heater block p10 to the pouch foil 1 is not uniform
Implementation Method 2
The heater p11 is inserted in the heater block p10 and elongated from a side in the longitudinal direction of the heater block p10. The larger the distance from a side to which a current is supplied to the heater p11, the larger the resistance, so more heat is generated.
Data Source
AI summary
A disclosed heater for a sealing process of a secondary battery includes: a sealing bar heating and pressing a pouch foil to be sealed; a plurality of sub-heating unit longitudinally disposed inside the sealing bar to respectively independently supply heat to a plurality of sections separated in the longitudinal direction of the sealing bar; temperature sensing units disposed inside the sealing bar and sensing temperature at positions on the surfaces being in contact with the pouch foil; and a control unit controlling heating temperature of the plurality of sub-heating units on the basis of the temperature sensed by the temperature sensing units.