Secondary Battery Insulating Tape Design for Short Circuit Prevention
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Solution Overview
Problem
Existing secondary batteries, particularly lithium ion batteries, are prone to internal short circuits due to the active material layer sliding off during assembly, which can lead to electrolyte depletion and increased risk of electrical shorts, bursting, or ignition. Current methods using adhesive tapes to prevent short circuits risk absorbing electrolyte and depleting it within the battery.
Innovation Solution
The use of insulating tape with a nonadhesive application area positioned centrally on the active material layer and a narrow adhesive application area on the cut end portion of the electrode plates, preventing the active material layer from sliding off and minimizing electrolyte absorption, thereby reducing the risk of internal short circuits and electrolyte depletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive tape is used to cover the entire active material layer to prevent short circuits, then electrical insulation is improved, but electrolyte absorption increases causing depletion
Solution Approach 1:
The insulating tape is designed with differentiated adhesive application: a nonadhesive application area (first area) and a limited adhesive application area (second area). This local quality differentiation allows the tape to provide electrical insulation where needed while minimizing electrolyte absorption by restricting adhesive contact with the electrolyte-exposed active material layer to only the narrowest necessary portion at the cut end.
2Stability of the object's composition
If adhesive tape covers the active material layer to prevent sliding off, then structural stability is improved, but electrolyte absorption increases
Solution Approach 1:
The adhesive is applied locally only to the narrowest necessary portion at the cut end of the electrode plate, rather than covering the entire active material layer. This provides just enough adhesive bonding to prevent sliding off during assembly while minimizing the surface area available for electrolyte absorption.
Solution Approach 2:
Instead of applying adhesive across the entire active material layer (excessive action), the invention applies adhesive only to the minimum necessary portion at the cut end (partial action), which is sufficient to prevent sliding off but insufficient to cause significant electrolyte depletion.
3Reliability
If insulating tape with adhesive is applied to the electrode plate end, then short circuit prevention is improved, but manufacturing complexity increases
Solution Approach 1:
The insulating tape's adhesive application is segmented into distinct zones: a nonadhesive first area and an adhesive second area. This segmentation allows the tape to fulfill multiple functions (insulation and limited bonding) in a single component without requiring multiple separate tape pieces or complex assembly steps.
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
This configuration effectively suppresses the sliding-off of the active material layer and minimizes electrolyte depletion, preventing electrical short circuits and maintaining battery capacity while ensuring safe operation by reducing the risk of internal shorts and electrolyte absorption.
Implementation Method 1
an adhesive application area, in which adhesive has been applied
Data Source
AI summary
The invention provides a secondary battery having positive electrode plates 14 and negative electrode plates, with insulating tapes 22A, 22B affixed to the cut end portions 14d, including an active material layer 14b portion thereof, of either the positive electrode plates 14 or the negative electrode plates, or both. These electrode plates are stacked or rolled alternately, with separators 23 interposed, into an electrode group that is sealed, together with electrolyte, inside a battery case. The insulating tapes 22A, 22B have an adhesive application area L2 and a nonadhesive application area L1, and are affixed in such a manner that the nonadhesive application area L1 is positioned centrally on the active material layer 14b of the electrode plate 14, and moreover so that part of the adhesive application area L2 is positioned on the active material layer 14b at the cut end portion 14d.