Electrode Tab Adhesive Connection for Overcharge Current Blocking
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Solution Overview
Problem
Lithium rechargeable batteries face safety risks such as explosion due to overcharge, high temperature, and external damage, and existing solutions compromise battery capacity and performance.
Innovation Solution
An electrode assembly with a conductive adhesive part containing a gas generation material between the electrode tab and current collector, which generates gas at a specific voltage to increase volume and resistance, ensuring safety without capacity reduction, and a manufacturing method that eliminates the need for welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety materials are added inside the cell to control abnormal operating states, then battery safety is improved, but battery performance such as rate characteristic and capacity is deteriorated
Solution Approach 1:
The invention extracts the safety function from the electrode structure by using the existing uncoated region of the current collector to form a conductive adhesive part with the electrode tab. This part can generate gas under overcharge conditions to block current, providing safety without requiring additional safety materials that would reduce battery capacity.
Solution Approach 2:
The conductive adhesive part serves multiple functions: it provides electrical connection between the electrode tab and current collector, acts as a current blocking mechanism under overcharge conditions through gas generation, and utilizes the existing uncoated region structure. This multi-functionality eliminates the need for separate safety materials.
2Reliability
If electrode tab is connected to current collector using conventional welding, then electrical connection is established, but manufacturing complexity and cost increase
Solution Approach 1:
The invention replaces the mechanical welding process with a chemical bonding process using conductive adhesive. The conductive adhesive part is formed by coating adhesive material on the uncoated region of the current collector, which then bonds to the electrode tab through drying and pressing, eliminating the need for welding equipment and processes.
3Ease of manufacture
If uncoated region is provided on current collector for tab connection, then tab attachment is enabled, but battery capacity is reduced due to loss of active material area
Solution Approach 1:
The invention applies local quality by providing the uncoated region only in the specific area where the electrode tab needs to be attached, rather than removing active material from the entire electrode surface. The uncoated region is precisely positioned and sized to accommodate the tab connection while preserving the maximum possible active material area for electrochemical reactions.
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 prevents overcharge-related hazards while maintaining battery capacity and performance, particularly in high-power models, by using a conductive adhesive part with a gas generation material to manage abnormal operating states without increasing resistance.
Implementation Method 1
a conductive adhesive part containing a gas generation material between the electrode tab and current collector, which generates gas at a specific voltage to increase volume and resistance
Implementation Method 2
generates gas at a specific voltage to increase volume and resistance
Data Source
AI summary
An electrode assembly having an improved electrode tab and current collector connection structure and a manufacturing method thereof are provided. The electrode assembly and the manufacturing method improve the connection structure between the electrode tab and the current collector, thereby ensuring safety with respect to overcharge, and battery capacity. The electrode assembly includes: an electrode current collector; an uncoated region in which an electrode active material layer is not formed at one surface of the electrode current collector; an electrode tab disposed at the uncoated region; and a conductive adhesive part disposed between the uncoated region and the electrode tab. The conductive adhesive part includes a gas generation material.