Battery Pack Cell Tab Bending for Impact Fracture Resistance
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Solution Overview
Problem
The rigidity of battery packs in laptops has decreased with the reduction in device size, making them prone to breakage due to external impacts, such as typing on a keyboard, which can cause cell tabs to fracture.
Innovation Solution
The battery pack design incorporates a cell tab that is bent multiple times, specifically with a first and second bending part, allowing it to absorb impact and prevent breakage by moving freely, while a support frame and insulation member further enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the battery pack size is reduced to fit smaller devices, then the device size is reduced, but the rigidity of the battery pack decreases making it prone to breakage from external impacts
Solution Approach 1:
The battery pack is divided into distinct functional modules: battery cells, protection circuit modules, insulation members, and support frames. This segmentation allows each component to be optimized independently for both size and strength, enabling compact overall design while maintaining structural rigidity through the support frame network.
Solution Approach 2:
The battery pack employs composite structural elements combining rigid support frames with flexible insulation members and protective sealants. The support frames provide structural rigidity, while the composite design allows the overall pack to maintain strength-to-weight ratio suitable for compact devices.
2Strength
If the battery pack is made more rigid to resist impacts, then the strength is improved, but the device size increases
Solution Approach 1:
Rather than uniformly increasing the rigidity of the entire battery pack, rigid support frames are strategically positioned only at critical locations where impact resistance is most needed, such as around the battery cells and protection circuit modules. This localized reinforcement maintains overall compactness while providing necessary strength.
Solution Approach 2:
The insulation members and sealing structures are designed with flexible, dynamic properties that allow them to deform under impact and return to original position, providing impact resistance without requiring rigid structural elements throughout the entire pack.
3Strength
If the cell tab is made rigid to maintain structural integrity, then the strength is improved, but the cell tab becomes prone to fracture from external impacts
Solution Approach 1:
The cell tab is designed with controlled bending radii and curvature parameters that allow it to flex under impact without fracturing. By optimizing the geometric parameters of the cell tab including bend locations and curvature radii, the design achieves both structural integrity for electrical connection and flexibility for impact resistance.
4Volume of moving object
If the protection circuit module is positioned closer to the battery cell to reduce size, then the device size is reduced, but the risk of electrolyte leakage affecting the circuit increases
Solution Approach 1:
An insulation member is introduced as an intermediary barrier between the battery cell and the protection circuit module. This insulation member prevents direct contact and potential contamination from electrolyte leakage, while allowing the two components to be positioned in close proximity for compact overall design. The sealant further mediates the interface between components.
Data Source
AI summary
A battery pack including a battery cell, the battery cell including a cell tab extending from a terrace part thereof; and a protection circuit module spaced apart from the battery cell and having a module tab to which the cell tab is welded, wherein the cell tab includes a bending part that is bent a predetermined number of times.