Battery Cell Casing Structure for Fatigue Crack Resistance
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Solution Overview
Problem
The service life of battery cells is limited by fatigue cracking in the casing due to the expansion of the electrode assembly, particularly near the connecting portions.
Innovation Solution
A battery cell design with a reinforced first zone in the casing, where the thickness of the first zone is greater than the second zone, located between the connecting portion, to mitigate fatigue cracking by distributing expansion forces more evenly and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the casing wall thickness is increased to prevent fatigue cracking, then the strength and service life are improved, but the device complexity and material usage increase
Solution Approach 1:
The casing wall thickness is varied locally rather than uniformly throughout. The first zone near the connecting portion has greater thickness to handle higher stress, while other areas maintain standard thickness. This localized reinforcement prevents fatigue cracking at critical areas without unnecessarily increasing overall complexity and material usage.
Solution Approach 2:
The casing wall is divided into multiple zones with different thickness characteristics. The first zone (near connecting portion) has greater thickness, while the second zone has standard thickness. This segmentation allows targeted reinforcement where needed while maintaining simplicity elsewhere in the structure.
2Strength
If the first zone thickness is increased to reinforce the connecting portion, then the resistance to fatigue cracking is improved, but the manufacturing complexity increases
Solution Approach 1:
The varying thickness design targets only the critical first zone near the connecting portion, leaving the rest of the casing with uniform thickness. This localized approach to quality enhancement provides the necessary strength improvement while minimizing the impact on manufacturing complexity, as only a specific region requires special attention during production.
Data Source
AI summary
A battery cell, a battery, and an electric device are disclosed. The battery cell includes a casing with an opening at one end, an end cover closing the opening, and an electrode assembly at least partially received in the casing. The casing has a wall welded to the end cover to form a connecting portion. The electrode assembly includes positive and negative electrode plates stacked in a direction parallel to the wall thickness, with the casing opening oriented in an intersecting direction. The wall includes a first zone and a second zone arranged along the length of the casing, the first zone being thicker and located between the connecting portion and the second zone. This structure reduces fatigue cracking near the connecting portion caused by expansion of the electrode assembly and thereby improves the service life of the battery cell.