Secondary Battery Current Collector Irregularity for Short Circuit Prevention
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Solution Overview
Problem
Secondary batteries face the challenge of preventing short circuits between positive and negative electrode plates due to small metal pieces generated during the ultrasonic bonding process, which can lead to reliability issues.
Innovation Solution
The implementation of an irregularity-formed portion on the current collector surface, which is covered by a cover member, effectively prevents small metal pieces from entering the electrode assembly, thereby preventing short circuits and enhancing battery reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic bonding is used to join core and current collector, then bonding strength is improved, but metal pieces are generated causing short circuit risk
Solution Approach 1:
The harmful metal pieces generated during ultrasonic bonding are extracted and isolated from the battery interior by placing them in a dedicated storage space formed by the cover member and protrusion, preventing them from causing short circuits while maintaining the bonding process
Solution Approach 2:
The cover member with protrusion acts as an intermediary structure that captures and contains metal pieces, serving as a mediator between the bonding process and the battery interior to prevent harmful interactions
2Reliability
If cover member is added to cover irregularity-formed portion, then reliability is improved, but device complexity increases
Solution Approach 1:
The cover member is integrated with the current collector structure, merging the protection function into an existing component rather than adding a completely separate element, thus reducing overall structural complexity while maintaining reliability improvement
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 solution effectively prevents small metal pieces from moving and causing short circuits, resulting in a highly reliable secondary battery by ensuring that the irregularity-formed portion on the current collector is covered, thus maintaining the integrity of the battery's electrical connections.
Implementation Method 1
vibration energy of ultrasonic waves is applied to the joint surface
Data Source
AI summary
A highly reliable secondary battery is provided, in which a short circuit between a positive electrode plate and a negative electrode plate is prevented. The negative electrode plate includes a negative electrode core and a negative electrode active material layer formed on the negative electrode core. An electrode assembly includes a negative electrode core-stacked portion including stacked layers of the negative electrode core, and the negative electrode core-stacked portion is joined to a first surface of the negative electrode current collector to form a joined portion. The irregularity-formed portion is formed on a second surface of the negative electrode current collector that is opposite to the first surface and is located in a portion of the negative electrode current collector in which the joined portion is formed. A sheet member used as a cover member is disposed on the second surface so as to cover the irregularity-formed portion.