Cylindrical Secondary Battery Layout Without a Negative Active Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cylindrical secondary batteries face challenges with high resistance and heat generation due to concentrated electric current in strip-like electrode tabs, leading to poor current collection efficiency and a need for high-capacity, high-energy density batteries with reduced costs.
Innovation Solution
A cylindrical secondary battery design featuring a positive electrode with a positive electrode active material layer and a negative electrode without an active material layer, utilizing a negative electrode current collector, which enhances energy density and reduces heat emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a strip-like electrode tab is used for current collection, then the battery structure is simple and easy to manufacture, but electric current concentrates in the tab causing large resistance and heat generation
Solution Approach 1:
The electrode tab is segmented into multiple tabs instead of using a single strip-like tab. This segmentation distributes the current collection points across multiple locations, reducing current density and heat generation at each tab while maintaining manufacturing simplicity
Solution Approach 2:
The current collection structure transitions from a one-dimensional strip-like tab to a multi-point distributed arrangement in two or three dimensions. This dimensional change increases the effective surface area for current collection and reduces resistance without complicating the manufacturing process
2Ease of manufacture
If lithium iron phosphate (LFP) is used as positive electrode active material, then the battery cost is reduced by about 30%, but the energy density decreases by about 20%
Solution Approach 1:
The invention changes the electrode configuration parameters by using a negative electrode without active material layer and optimizing the positive electrode structure. This allows increased loading of LFP active material and improved spatial utilization, achieving higher energy density with cost-effective LFP material
3Reliability
If a negative electrode active material layer is included, then the battery has balanced electrochemical performance, but the manufacturing complexity and cost increase
Solution Approach 1:
The negative electrode active material layer is extracted (removed) from the battery structure, leaving only the negative electrode current collector. This simplifies manufacturing while the current collector still provides necessary electrical function and structural support
Solution Approach 2:
The negative electrode current collector serves multiple functions: providing electrical conductivity, maintaining structural integrity, enabling current collection, and facilitating electrolyte distribution. This multi-functionality compensates for the absence of active material layer
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 battery achieves increased energy density per volume, improved safety, and reduced manufacturing complexity by eliminating the negative electrode active material layer, while maintaining stability and efficiency.
Implementation Method 1
The lithium secondary battery generates electric energy through the oxidation and reduction upon the intercalation/deintercalation of lithium ions to/from the positive electrode and negative electrode
Implementation Method 2
The lithium secondary battery generates electric energy through the oxidation and reduction upon the intercalation/deintercalation of lithium ions
Implementation Method 3
the negative electrode includes a negative electrode current collector but has no negative electrode active material layer
Data Source
AI summary
A cylindrical secondary battery and a method for manufacturing the same are provided. The cylindrical secondary battery includes a negative electrode having no negative electrode active material layer, and thus a large-scale cylindrical secondary battery having a high energy density, improved cell performance, and ensured safety can be provided.