Secondary Battery Electrolyte Injection Layout to Prevent Core Collapse
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Solution Overview
Problem
The center liquid injection approach for secondary batteries can cause local collapse at the winding cell through hole, affecting the integrity of the electrode sheet interface and reducing charge and discharge performance and cycle stability.
Innovation Solution
A secondary battery design with a liquid injection hole positioned at the outer periphery of the winding cell through hole, utilizing a second cover plate with through holes or grooves to direct electrolyte flow away from the winding cell through hole, enhancing electrolyte infiltration speed and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the liquid injection hole is arranged at the center (through the winding cell through hole), then the electrolyte can be injected directly into the inner portion of the casing, but the high flow rate electrolyte causes local collapse at the winding cell through hole position, affecting electrode sheet interface integrity and reducing charge-discharge performance and cycle stability
Solution Approach 1:
The patent transitions from center injection (one-dimensional approach through the winding cell through hole) to peripheral injection (utilizing the circumferential direction around the winding cell through hole). The liquid injection hole is positioned at the peripheral portion of the cover plate, directing electrolyte flow along the radial direction toward the electrode assembly edge, thereby avoiding the collapse issue at the center while maintaining effective infiltration.
Solution Approach 2:
The current collector serves as an intermediary structure that guides electrolyte distribution. The electrolyte flows through the liquid injection hole in the cover plate, then distributes through the current collector's peripheral region before penetrating the electrode assembly, providing a controlled intermediate pathway that prevents direct high-velocity impact on the winding cell through hole.
2Device complexity
If the electrolyte flows through the separator first to penetrate the electrode sheet, then the injection process can be simplified, but the wetting speed of the electrode assembly is limited
Solution Approach 1:
The peripheral liquid injection approach performs preliminary wetting of the electrode assembly from the outer edges inward. By injecting at the periphery and allowing electrolyte to spread radially through the current collector and separator before reaching the electrode sheets, the system achieves faster overall wetting speed without requiring complex multi-stage injection processes.
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
Reduces the likelihood of winding cell through hole collapse, improves charge-discharge performance, and increases electrolyte wetting speed and cycle stability.
Implementation Method 1
the sealing plate seals the liquid injection hole
Implementation Method 2
when the electrolyte flows inside the secondary battery, it needs to first penetrate the separator
Implementation Method 3
The second cover plate at least partially blocks the first through hole and is welded to the first cover plate
Data Source
AI summary
A secondary battery, a battery pack, and an electronic device are provided. The secondary battery includes a casing, an electrode assembly, a current-collecting member, and a sealing plate. The casing includes a side wall and a cover plate assembly. The side wall includes an opening sealed by the cover plate assembly. The electrode assembly mounted in the casing has a winding cell through hole. The current-collecting member is arranged on a side of the electrode assembly facing the cover plate assembly and is electrically connected to the electrode assembly and the casing. The sealing plate arranged on a side of the cover plate assembly away from the electrode assembly. The cover plate assembly is provided with a liquid injection hole. A projection of the liquid injection hole is located at an outer periphery of the winding cell through hole, and the sealing plate seals the liquid injection hole.