Grooved Electrode and Bent Tab Structure for Safer Secondary Batteries
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Solution Overview
Problem
Existing secondary batteries face challenges in improving energy density and safety due to thickness issues from grooved electrode plates, potential short-circuits, and vulnerability to external impacts.
Innovation Solution
The secondary battery design incorporates grooves in the electrode plates and bent tabs with insulation pieces to reduce thickness, enhance energy density, and improve safety by buffering external forces, while laser welding and insulation pieces prevent short-circuits and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If grooves are added to the electrode plate to reduce thickness, then energy density is improved, but the structural strength and interface quality may deteriorate
Solution Approach 1:
The electrode plate is segmented by introducing grooves that divide the active material layer into multiple regions. This segmentation reduces the thickness of the electrode plate while maintaining sufficient structural strength through the divided structure, thereby improving energy density without compromising strength
Solution Approach 2:
Different regions of the electrode plate are given different properties through the groove structure. The grooved regions have reduced thickness for higher energy density, while the ridges between grooves maintain greater thickness for structural support, creating local quality variations that resolve the contradiction
2Quantity of substance
If grooves are added to the electrode plate to reduce thickness, then energy density is improved, but the risk of short-circuit increases
Solution Approach 1:
An insulating piece is introduced as an intermediary element between the grooved electrode plate and other components. This insulating piece fills the grooves and provides electrical insulation, preventing short-circuits while allowing the grooved structure to maintain reduced thickness for improved energy density
3Quantity of substance
If the tab thickness is reduced to improve energy density, then the battery thickness is reduced, but the connection reliability deteriorates
Solution Approach 1:
A bent portion is pre-formed in the tab structure before assembly. This bent portion acts as a cushioning element that absorbs external forces and prevents direct stress transmission to the connection point, maintaining connection reliability even with reduced tab thickness for improved energy density
4Object-affected harmful factors
If the bent portion angle is optimized to buffer impact forces, then safety is improved, but the tab structure complexity increases
Solution Approach 1:
The bent portion angle is optimized within a specific range (20°-70°) to achieve effective impact buffering. By controlling the angle parameter within this range, the structure achieves sufficient safety performance without excessive complexity, as the angle optimization provides effective cushioning with a relatively simple geometric modification
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 enhances energy density, reduces the risk of short-circuits and detachment, and improves safety by mitigating impact forces, ensuring reliable connections and sealing performance.
Implementation Method 1
The first bent portion is bent relative to the second connecting portion toward the second direction. The first bent portion produces a buffering effect when the first tab is impacted by an external force, reduces the pulling force between the second connecting portion and the first region
Implementation Method 2
laser welding and insulation pieces prevent short-circuits and detachment
Data Source
AI summary
A secondary battery includes a housing, a first tab, and an electrode assembly. The electrode assembly includes a first electrode plate. The first electrode plate includes a first current collector, a first active material layer disposed on a first surface of the first current collector and a second active material layer disposed on a second surface of the first current collector. The first active material layer is provided with a first groove exposing a first region of the current collector. A second region of the first current collector is covered with a second active material layer. The first region is opposite to the second region in a second direction. The first tab includes a first connecting portion, a first bent portion, and a second connecting portion that are connected in sequence.