Wound Electrode Assembly Bonding to Prevent Pouch Cell Shift
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Solution Overview
Problem
Current electrochemical apparatuses lack effective safety measures to prevent damage and hazards from drops or collisions, particularly due to relative movement between the packaging bag and electrode assembly, which can cause damage to the electrode assembly.
Innovation Solution
An electrochemical apparatus with a winding structure and connecting layers, including adhesive and gluing layers, to strengthen the connection between the electrode assembly and packaging bag, preventing relative movement and maintaining the assembly's integrity during drops or collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the packaging bag and electrode assembly are allowed to move relative to each other during drops, then the structure remains simple, but the electrode assembly is damaged
Solution Approach 1:
The connecting layer is pre-applied to the packaging bag surface before the electrode assembly is placed inside. This preliminary action ensures that when the battery undergoes drop or collision, the connecting layer is already in position to prevent relative movement between the packaging bag and electrode assembly, thereby avoiding damage without requiring complex additional structures.
Solution Approach 2:
The connecting layer acts as an intermediary substance between the packaging bag and the electrode assembly. It mediates the interaction between these two components by providing adhesive bonding that prevents relative movement during mechanical shocks, thus protecting the electrode assembly while maintaining structural simplicity.
2Reliability
If connecting layers are added to strengthen the connection between packaging bag and electrode assembly, then safety performance improves, but device complexity increases
Solution Approach 1:
The connecting layer is applied locally at specific positions on the packaging bag where connection to the electrode assembly is needed, rather than uniformly across the entire surface. This localized application strengthens the connection at critical points while avoiding unnecessary material usage and structural complexity in non-critical areas.
3Reliability
If the electrode assembly is tightly fixed to prevent relative movement, then safety improves, but manufacturing precision requirements increase
Solution Approach 1:
The connecting layer changes the bonding parameters between the packaging bag and electrode assembly by providing an adhesive interface with appropriate bond strength. This allows for effective fixation that prevents relative movement during drops while accommodating normal manufacturing tolerances, thus achieving safety improvement without excessively stringent precision requirements.
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
Enhances safety performance by preventing the electrode assembly from tearing and improving energy density and overall flatness without increasing thickness or volume, thus reducing risks of damage and enhancing stability.
Implementation Method 1
An adhesive layer is pasted to a part of an inner surface of the flat portion facing toward a winding center of the electrode assembly
Implementation Method 2
The first connecting layer includes a first surface that is opposite to an inner surface of the packaging bag and a second surface that is opposite to the first surface. The second surface of the first connecting layer is pasted to a part of an outer surface of the first bending portion and to a part of an outer surface of the flat portion
Data Source
AI summary
An electrochemical apparatus includes an electrode assembly, a packaging bag and a first connecting layer. The electrode assembly includes an adhesive layer. An outermost current collector of the electrode assembly includes a first bending portion, a second bending portion opposite to the first bending portion and a flat portion connected between the first bending portion and the second bending portion. The adhesive layer is pasted to a surface of the flat portion facing toward a winding center of the electrode assembly. The packaging, bag is configured to accommodate at least a part of the electrode assembly. The first connecting layer is pasted to the first bending portion and to a part of an outer surface of the flat portion. A projection of the second connecting, layer and a projection of the adhesive layer in a direction perpendicular to an outer surface of the flat portion have an overlapping zone.