Lithium-Ion Battery Terminal Joint Layout for Ignition Prevention
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Solution Overview
Problem
Lithium ion batteries require further improvement in safety, particularly as they scale in size and energy density, to prevent ignition and explosion risks.
Innovation Solution
Incorporating non-joint portions on the most distal ends of electrode current collectors where electrode terminals are not joined, enhancing the welding process to reduce resistance and heat generation at the joint points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode terminal is joined to the entire distal end of the current collector, then electrical connection is maximized, but safety against ignition is reduced
Solution Approach 1:
The distal end of the current collector is divided into two functional zones: a joint portion that provides electrical connection and a non-joint portion that serves as a safety buffer zone. This segmentation prevents the welding electrode from contacting the active material at the very edge, eliminating the ignition risk while maintaining electrical connectivity through the joint portion.
Solution Approach 2:
The harmful function (ignition risk) is extracted by removing the welding electrode contact from the distal end region. The non-joint portion acts as an isolated safety zone that is deliberately excluded from the welding process, separating the electrical connection function from the safety protection function.
2Use of energy by moving object
If the battery size is increased to achieve higher energy density, then energy capacity is improved, but safety control becomes more difficult
Solution Approach 1:
The current collector is designed with non-uniform properties: the joint portion has optimized welding characteristics for electrical connection, while the non-joint portion has different properties (no active material coating, extended length) that provide safety buffer. This local differentiation allows the battery to achieve high energy density through optimized active material regions while maintaining safety through the specially designed non-joint portion.
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 design significantly enhances safety by preventing ignition and reducing thermal runaway, while allowing for a smaller and lighter battery design.
Implementation Method 1
enhancing the welding process to reduce resistance and heat generation at the joint points
Implementation Method 2
enhancing the welding process to reduce resistance and heat generation at the joint points
Data Source
AI summary
A lithium ion battery (100) of the invention includes a battery main body (50) which includes one or more power generation elements configured by laminating a positive electrode layer (1) including a positive electrode active material layer (2) and a positive electrode current collector (3), an electrolyte layer including a separator (20) and an electrolytic solution, and a negative electrode layer (6) including a negative electrode active material layer (7) and a negative electrode current collector (8), in this order, an outer package (30) in which the battery main body (50) is sealed, a positive electrode terminal (11) which is electrically connected to the positive electrode current collector (3) and at least a part of which is exposed to the outside of the outer package (30), and a negative electrode terminal (16) which is electrically connected to the negative electrode current collector (8) and a part of which is exposed to an outside of the outer package (30). In the lithium ion battery (100) of the embodiment, an end portion (5) on an outer side of the negative electrode current collector (8) and an end portion (17) on an inner side of the negative electrode terminal (16) are joined with each other, and the lithium ion battery includes a first non-joint portion (21) which is not joined with the negative electrode terminal (16), on a most distal end portion (5A) on the outer side of the negative electrode current collector (8). In addition, in the lithium ion battery (100) of the embodiment, an end portion (10) on the outer side of the positive electrode current collector (3) and an end portion (18) on the inner side of the positive electrode terminal (11) are joined with each other, and the lithium ion battery includes a third non-joint portion (23) which is not joined with the positive electrode terminal (11), on a most distal end portion (10A) on the outer side of the positive electrode current collector (3).