Lithium-Ion Battery Electrode Joint Layout to Limit Welding Heat
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Solution Overview
Problem
Lithium ion batteries require further improvements in safety, particularly as they scale in size and energy density, to prevent ignition and explosion risks.
Innovation Solution
The lithium ion battery design incorporates non-joint portions on the most distal ends of the electrode current collectors, where the electrode terminals are not joined, to reduce resistance and heat generation during welding, thereby enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode terminal is joined to the entire surface of the electrode current collector, then the electrical connection is improved, but the heat generation and ignition risk increase
Solution Approach 1:
The electrode current collector is divided into two functional regions: a joint portion where the electrode terminal is connected for electrical conduction, and a non-joint portion that extends beyond the joint portion to prevent heat concentration and ignition. This segmentation allows the battery to maintain good electrical connection while reducing heat generation risk at the terminal connection point.
2Quantity of substance
If the battery size and energy density are increased, then the power capacity is improved, but the safety against ignition and explosion deteriorates
Solution Approach 1:
The non-joint portion of the electrode current collector acts as a pre-designed safety buffer that prevents heat concentration and ignition before thermal runaway can occur. This structural feature provides beforehand protection against ignition and explosion risks, allowing the battery to achieve higher energy density while maintaining safety.
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 effectively prevents ignition and thermal runaway by reducing joint resistance and heat generation, allowing for larger and higher energy density batteries without increasing weight or size.
Implementation Method 1
an end portion on an outer side of the negative electrode current collector and an end portion on an inner side of the negative electrode terminal are joined with each other, and a first non-joint portion which is not joined with the negative electrode terminal is included on a most distal end portion on the outer side of the negative electrode current collector
Data Source
AI summary
Described is a lithium ion battery comprising terminals and more than one power generation element, each having current collectors. Each negative electrode current collector having an uncoated portion including an angled portion, wherein an end portion thereof and an end portion on an inner side of a negative electrode terminal are joined with each other in a negative electrode joint portion by welding. The end portion on the uncoated portion of a negative electrode current collector and end portions of the uncoated portions of the other negative electrode current collectors are overlapped and joined with each other at a negative electrode joint portion. The lithium ion battery further comprises a first non-joint portion in which a most distal end portion on the uncoated portion of each negative electrode current collector is overlapped, but not welded to each other or the negative electrode terminal. The first non-joint portion extends from a distal edge portion of the uncoated portion of each negative electrode current collector to the negative electrode joint portion in a direction opposite to a predetermined one direction and a maximum length of the first non-joint portion in the predetermined one direction is specified. Variants and alternatives are also described.