Battery Electrode Primer Coating to Prevent Drop-Induced Sliding
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Solution Overview
Problem
Secondary batteries, particularly lithium-ion batteries, face safety issues due to the electrode assembly sliding within the housing during drops, leading to potential failure and damage, which existing solutions like double-sided tape or reinforced packaging fail to adequately address effectively and efficiently.
Innovation Solution
A secondary battery design featuring a positive electrode plate with a primer coating that includes a first and second primer coating, where the second primer coating on the outermost turn has a raised and recessed region, providing a high friction coefficient with the housing to prevent sliding and enhance structural stability, thereby improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If double-sided tape or reinforced packaging is used to prevent electrode assembly sliding, then safety performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The primer coating is applied locally only on the outermost turn of the electrode assembly rather than uniformly throughout. This localized treatment creates a rough surface structure precisely where needed to prevent sliding during drops, while keeping the rest of the battery structure simple and maintaining ease of manufacture
Solution Approach 2:
The invention changes the surface parameter (roughness) of the primer coating on the outermost turn to increase the friction coefficient. By controlling the roughness parameter of the primer coating, the electrode assembly gains enhanced grip against the housing wall without adding complex structural elements
2Reliability
If double-sided tape or reinforced packaging is used to prevent electrode assembly sliding, then safety performance is improved, but manufacturing cost increases
Solution Approach 1:
The rough surface structure is created locally only on the outermost turn through primer coating, rather than reinforcing the entire battery structure. This localized approach reduces material costs and simplifies the manufacturing process while still achieving the safety performance goal of preventing electrode assembly sliding during drops
Solution Approach 2:
The primer coating provides a cost-effective solution compared to expensive reinforced packaging structures. The coating is applied during normal manufacturing and provides sufficient protection without requiring additional expensive materials or complex assembly steps
3Reliability
If the primer coating is made rougher to increase friction coefficient, then safety performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention applies the rough primer coating only on the outermost turn of the electrode assembly rather than requiring uniform rough coating throughout. This localized application reduces the overall manufacturing precision requirements while still achieving the necessary friction coefficient enhancement for safety
Solution Approach 2:
The primer coating is applied to cover the outermost turn completely, ensuring that even with variations in coating thickness, the rough surface structure is present wherever the outermost turn contacts the housing wall during a drop, providing a safety margin
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 significantly reduces the risk of battery failure from drops by maintaining a high friction coefficient and structural stability, while simplifying manufacturing and reducing costs without introducing complex structures.
Implementation Method 1
the second primer coating disposed on at least a part of the surface of the outermost turn of the electrode assembly is rougher than a blank positive current collector or a uniform-thickness primer coating, so as to provide a relatively high friction coefficient between the outermost turn of the electrode assembly and the inner wall of the housing
Data Source
AI summary
A secondary battery includes an electrode assembly and a housing accommodating the electrode assembly. The electrode assembly includes a positive electrode plate having a positive current collector and a primer coating applied on a surface of the positive current collector. Along a winding direction of the electrode assembly, the primer coating includes a first primer coating and a second primer coating. A positive active material layer is located on a surface of the first primer coating. The second primer coating is disposed on at least a part of a surface of an outermost turn of the electrode assembly. The positive active material layer is not disposed on a surface of the second primer coating. A raised region and a recessed region are disposed on the second primer coating. An area of the raised region accounts for 50% to 80% of an area of the second primer coating.