Stacked Lithium Ion Battery Electrode Design for Space Efficiency
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Solution Overview
Problem
Cylindrical lithium ion secondary batteries have low space usage efficiency, high internal resistance, and reduced battery capacity due to uneven current distribution and low conductivity of electrodes.
Innovation Solution
A stacked-type lithium ion secondary battery design with alternately placed positive and negative electrodes separated by a spiral-shaped separator, wrapped around an electrode core, which increases space efficiency and reduces internal resistance by improving current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical rolled electrodes are used in rectangular battery shells, then the battery structure is simple to manufacture, but the space usage efficiency is low
Solution Approach 1:
The patent transitions from a two-dimensional rolled electrode structure (cylindrical) to a three-dimensional stacked electrode structure that fully utilizes the rectangular battery shell space. The electrodes are stacked in layers with separators between them, creating a volumetric arrangement that matches the rectangular container geometry, thereby significantly improving space usage efficiency while maintaining manufacturing feasibility through layer-by-layer assembly
2Device complexity
If single or multiple conductors are used for current conduction, then the device complexity is low, but the internal resistance is high and current distribution is uneven
Solution Approach 1:
The patent divides the current conduction system into multiple independent conductors (first conductor and second conductor) that are spatially separated and connected to different electrode regions. This segmentation allows current to flow through multiple parallel paths, reducing overall internal resistance and achieving more uniform current distribution across the electrodes during charge and discharge cycles
Solution Approach 2:
The patent introduces a spatial dimension to current conduction by positioning conductors at different locations and orientations within the battery. The first conductor connects to one set of electrode terminals while the second conductor connects to another set, creating a multi-dimensional current distribution network that improves electrical performance without significantly increasing structural complexity
Data Source
AI summary
A type of lithium ion secondary battery is disclosed; therein, the positive electrode 1 is formed by smearing an active material on the surface of an aluminum foil body, where said active material is compound oxide(s) comprising transition metals and lithium capable of absorbing and releasing lithium ions; the negative electrode 2 is formed by smearing an active material on the surface of a copper foil body, where said active material includes carbon material capable of absorbing and releasing lithium ions. Both the positive and negative electrodes have conducting strips acting as current conductors 6, 7. The positive and negative electrodes 1, 2 are in plate form and are alternately stacked on both sides of the belt-shaped separator 3 to form the electrode core 4. The separator 3 wraps around said electrode plates and separates the positive and negative electrodes 1, 2. This type of lithium ion secondary battery can effectively use the internal space of a battery shell, increase the battery's energy density, improve the large current discharge characteristic of the lithium ion secondary battery, the self-discharge ability, the battery's cycling capability and the battery's capacity.