Shared Electrode Segments in Stepped Battery Cells
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Solution Overview
Problem
Conventional lithium ion batteries with stepped structures have inefficiencies due to unused active materials on electrode surfaces and mechanical instability caused by relative movement between the step cell and main cell, leading to reduced energy density and cyclability.
Innovation Solution
A lithium ion battery design where one or more segments of an electrode are shared between the main and step electrode assemblies, optimizing active material participation in electrochemical reactions and enhancing mechanical integrity through strategic segment placement and shared separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrodes are coated with active materials on both surfaces from head to tail in conventional stepped batteries, then the battery structure is simple and easy to manufacture, but active materials on some parts do not participate in electrochemical reactions, reducing energy density
Solution Approach 1:
The electrode is divided into multiple segments along its length, with different coating patterns on each segment. Specifically, the electrode includes a first segment with active material on both surfaces, a second segment with active material on one surface, and a third segment with active material on both surfaces again. This segmentation allows different portions of the electrode to serve different functions, maximizing active material utilization while maintaining structural integrity.
Solution Approach 2:
Different regions of the electrode are given different local properties through selective coating. The first and third segments have double-sided coating for maximum capacity, while the second segment has single-sided coating to prevent interference with the step cell structure. This local differentiation ensures that active materials are strategically placed where they can effectively participate in electrochemical reactions.
2Device complexity
If the step cell is directly stacked on the main cell without sharing electrodes, then the battery structure is simple, but the step cell and main cell can shift relatively to each other, jeopardizing mechanical integrity
Solution Approach 1:
The step cell and main cell share common electrode segments and separators. The electrode structure is designed such that the first electrode assembly and second electrode assembly share at least one common separator, and certain electrode segments are common to both cells. This merging approach eliminates relative movement between cells while improving space utilization and mechanical stability.
Solution Approach 2:
The shared electrode segments and separators serve multiple functions: they act as electrodes for both the step cell and main cell simultaneously, and the shared separator provides both electrical insulation and mechanical bonding between the two cells. This multi-functionality reduces overall device complexity while enhancing mechanical integrity through the shared structural elements.
3Ease of manufacture
If conventional stepped batteries use separate electrodes for step cell and main cell, then each cell is independent and easy to assemble, but space is wasted and active materials are underutilized
Solution Approach 1:
The step cell and main cell share common electrode segments and separators, merging what would traditionally be separate components. The shared separator and electrode segments eliminate redundant structures, maximizing space utilization within the battery housing while maintaining ease of assembly through a modular design approach.
Solution Approach 2:
The shared electrode segments serve dual purposes as electrodes for both the step cell and main cell, while the shared separator provides both insulation and structural support. This universal design eliminates wasted space that would otherwise be occupied by separate electrode structures for each cell.
Data Source
AI summary
A battery comprises a first electrode assembly including a first electrode, and a second electrode assembly disposed adjacent the first electrode assembly along a first direction. The first electrode comprises a first segment that is disposed on an outer portion of the second electrode assembly. The first electrode may further comprise a second segment electrically connected to the first segment. The second segment is disposed on an outer portion of the first electrode assembly.