Polymer Battery Pack Resin Sheath Impact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polymer battery packs are prone to damage from external impacts due to the weakness of their pouch-type bare cells and plastic cases, which can lead to safety issues like smoke or explosions, and are limited in capacity due to the need for a rib margin for ultrasonic welding, restricting the size of the core pack and thus the battery's capacitance.
Innovation Solution
A polymer battery pack design that encloses the bare cell and protection circuit member with a high-strength resin sheath and finishing tape, allowing the main walls to be exposed and reducing the thickness of the frame case and sheath to increase capacity, while maintaining strength and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the plastic case is made thin to reduce size, then the battery pack size is reduced, but the strength against external impact deteriorates
Solution Approach 1:
The patent applies composite materials by combining the plastic case with a resin sheath made of different material (e.g., metal or reinforced polymer). This composite structure provides both the space efficiency of a thin case and the impact resistance of the resin sheath, resolving the contradiction between size reduction and strength maintenance.
Solution Approach 2:
The resin sheath acts as a flexible protective layer that can be applied as a thin film or shell over the plastic case. This thin protective layer adds strength against external impact without significantly increasing the overall battery pack size, addressing the contradiction between thin case design and impact resistance.
2Strength
If the rib margin is increased for ultrasonic welding, then the welding strength is improved, but the core pack size is reduced
Solution Approach 1:
The patent replaces the mechanical ultrasonic welding system with an adhesive bonding system. The resin sheath is adhesively bonded to the plastic case, eliminating the need for rib margins and ultrasonic welding equipment. This substitution allows the core pack to utilize the full available space without sacrificing bonding strength.
Solution Approach 2:
The invention extracts and eliminates the rib margin structure from the design. By removing this unnecessary structural feature, the core pack can be maximized in size while the adhesive bonding system provides the required structural strength without requiring marginal areas.
3Quantity of substance
If the plastic case is made thin to increase core pack capacity, then the battery capacitance is increased, but the reliability against piercing damage deteriorates
Solution Approach 1:
The patent uses composite materials by combining the thin plastic case with a resin sheath layer. This composite structure maintains the thin profile needed for high capacitance while adding piercing resistance through the resin sheath, resolving the contradiction between capacitance increase and reliability maintenance.
Solution Approach 2:
The resin sheath serves as a beforehand cushioning layer that protects the thin plastic case from piercing damage before such damage can occur. This preventive protective layer allows the case to be made thin for high capacitance while maintaining reliability against piercing threats.
Data Source
AI summary
A polymer battery pack includes: a bare cell having main walls and sub-walls; a protection circuit member which is electrically connected to the bare cell; a resin sheath which encloses the sub-walls of the bare cell in such a way that the main walls are exposed to the outside; and finishing tape attached to the main walls of the bare cell. A frame case may be interposed between the bare cell and the resin sheath. In the battery pack, a strong resin sheath and finishing tape or a frame case are engaged with the bare cell, thereby reinforcing the strength of the bare cell and improving the reliability of the bare cell. Also, the battery pack does not require a separate space for the supersonic welding, and thus can receive a bare cell of high capacitance. A method of manufacturing the polymer battery pack includes forming a bare cell, forming a core pack by positioning and electrically interconnecting a protection circuit member with the bare cell, and molding a resin sheath accommodating the resin sheath enclosing the core pack and the electrode terminals of the protection circuit member are exposed to the outside. A frame case can be formed and engaged with the bare cell to be included in the core pack.