Secondary Battery Conductive Paste Sealing and Venting
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Solution Overview
Problem
Secondary batteries face challenges in achieving increased sealing strength and improved safety, particularly in preventing gas release and explosion during abnormal operations.
Innovation Solution
The design incorporates a conductive paste to electrically connect the case and first current collector plate, while physically fixing them, and includes a cap plate with a receiving portion and gasket to enhance sealing, along with an elastically deformable first current collector plate and safety vent features to manage pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing methods are used to close the case opening, then the battery can be assembled, but the sealing strength is insufficient and gas release cannot be prevented during abnormal operations
Solution Approach 1:
The cap plate is constructed as a composite structure integrating multiple functional layers: a sealing layer (aluminum foil or polymer) for gas tightness, a reinforcement layer (metal mesh or fabric) for mechanical strength, and a conductive layer for electrical connectivity. This composite design simultaneously achieves explosion-proof sealing strength and electrical functionality without requiring separate components.
Solution Approach 2:
The cap plate is designed to perform multiple functions simultaneously: sealing the case opening to prevent gas release, providing mechanical reinforcement to the case structure, establishing electrical connection between the electrode assembly and external terminals, and serving as a safety vent mechanism. This multi-functional integration resolves the contradiction by eliminating the need for separate sealing components while enhancing overall reliability.
2Stability of the object's composition
If the first current collector plate is rigid to maintain structural stability, then assembly is simplified, but it cannot accommodate electrode assembly expansion and contraction during charging cycles
Solution Approach 1:
The first current collector plate is designed with dynamic characteristics, being elastically deformable to accommodate the expansion and contraction of the electrode assembly during charging and discharging cycles. This elasticity allows the plate to flexibly adapt to volume changes while maintaining continuous electrical contact, resolving the contradiction between structural stability and adaptability.
Solution Approach 2:
The mechanical properties of the first current collector plate are optimized by selecting materials and designs that exhibit appropriate elastic modulus and flexibility. The plate's physical parameters (flexibility, thickness, material composition) are specifically tuned to enable elastic deformation within acceptable ranges, allowing it to maintain stability while adapting to electrode volume changes during operation.
3Reliability
If welding is used to connect the case and current collector plate, then electrical connection is reliable, but spatters are generated causing safety issues
Solution Approach 1:
The welding process (thermal/mechanical system) is replaced with a mechanical pressing system. The cap plate is pressed onto the case and current collector plate using pressing members that apply controlled force, creating reliable electrical and mechanical connections without generating spatters or requiring high temperatures. This substitution eliminates the harmful effects of welding while maintaining connection reliability.
Solution Approach 2:
Conductive paste is introduced as an intermediary material between the case and the first current collector plate. This paste facilitates reliable electrical connection through mechanical pressure alone, eliminating the need for welding. The conductive paste fills micro-gaps and ensures continuous electrical contact while the mechanical pressing process avoids generating harmful spatters.
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 significantly increases sealing strength and safety by preventing gas release and explosion, ensuring the battery's integrity and reliability.
Implementation Method 1
a conductive paste electrically connecting the case and the first current collector plate while physically fixing the case and the first current collector plate
Implementation Method 2
the first current collector plate may include a first region in contact with the first electrode plate, and a second region in contact with the cap plate, and be elastically deformably bent such that the first region has a height difference with respect to the second region
Data Source
AI summary
A secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case including a first side having an opening to accommodate the electrode assembly; a cap plate sealing the first side of the case; a first current collector plate arranged between the electrode assembly and the cap plate; a conductive paste electrically connecting the case and the first current collector plate while physically fixing the case and the first current collector plate; a terminal arranged on a second side of the case; and a second current collector plate electrically connecting the second electrode plate and the terminal.