Battery Cell Tab Protective Film Layout to Prevent Root Cracking
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Solution Overview
Problem
Tab cracking during the assembly of battery cells leads to reduced current flow capacity and increased risk of short circuits, affecting the service life of batteries.
Innovation Solution
A protective film with a non-adhesive region covering the root section of the tab is used to reduce the pulling force on the tab, thereby minimizing cracking and ensuring stable connection and current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the protective film is fully bonded to the tab including the root section, then the bonding strength is improved, but the tab cracking risk increases due to pulling force on the weak root section
Solution Approach 1:
The protective film is divided into three distinct regions: a first adhesive region bonded to the main body, a non-adhesive region covering the root section, and a second adhesive region bonded to the connecting section. This segmentation allows different portions of the protective film to have different bonding characteristics, preventing cracking at the weak root section while maintaining bonding strength at the main body and connecting section.
Solution Approach 2:
The protective film exhibits local quality variation through the non-adhesive region that specifically covers the root section. This local modification creates a non-adhesive zone exactly where the tab is most vulnerable to cracking, while other regions maintain full adhesive properties for secure bonding.
2Reliability
If the non-adhesive region covers only part of the root section, then the pulling force is reduced, but the coverage of the weak junction area may be insufficient
Solution Approach 1:
The non-adhesive region is pre-positioned to cover the root section and extend to exceed the junction between the root section and the main body before bonding occurs. This preliminary positioning ensures that the weak junction area is protected from cracking during the bonding process and subsequent operation, addressing the most vulnerable point proactively.
Solution Approach 2:
The non-adhesive region is designed to extend beyond the junction between the root section and the main body to preemptively counteract the pulling force that would otherwise concentrate stress at this weak junction point, preventing cracking before it can occur.
3Reliability
If the non-adhesive region covers the entire connecting section, then the cracking risk at the junction is reduced, but the bonding strength at the connecting section decreases
Solution Approach 1:
The protective film is segmented such that the non-adhesive region covers only a portion of the connecting section (area ratio S1/S2 between 1/3 and 2/3), leaving portions of the connecting section exposed for bonding. This segmentation balances cracking prevention with bonding strength requirements.
Solution Approach 2:
The area ratio of the non-adhesive region covering the connecting section is controlled within a specific range (1/3≤S1/S2≤2/3). This parameter optimization ensures sufficient coverage to protect the junction from cracking while maintaining adequate bonding area to preserve bonding strength at the connecting section.
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
The solution effectively prolongs the service life of the battery cell by preventing tab cracking and short circuits, maintaining current flow capacity.
Implementation Method 1
a protective film, including a first adhesive region, a second adhesive region, and a non-adhesive region located between the first adhesive region and the second adhesive region, where the first adhesive region is bonded to the main body, the second adhesive region is bonded to the connecting section, and the non-adhesive region covers the root section
Data Source
AI summary
Provided are a battery cell, a battery, an electric device, and a manufacturing method and device of battery cell. The battery cell includes: an adapting piece; an electrode assembly including a main body and a tab extending from the main body, where the tab includes a root section and a connecting section, the root section being connected to the main body and the connecting section being connected to the adapting piece; and a protective film including a first adhesive region, a second adhesive region, and a non-adhesive region located between the first adhesive region and the second adhesive region, where the first adhesive region is bonded to the main body, the second adhesive region is bonded to the connecting section, and the non-adhesive region covers the root section. The battery cell has prolonged service life.