Battery Cell Electrode Layout for Pressure Relief Reliability
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Solution Overview
Problem
The reliability of pressure relief structures in battery cells is poor, leading to potential damage and liquid leakage during thermal runaway due to excessive pulling effects on the housing walls.
Innovation Solution
Configure at least one electrode plate layer as a first preset electrode plate layer with a greater distance between its active substance layer and the housing wall, reducing the amount of active substance proximal to the wall and minimizing the pulling effect on the pressure relief structure, thereby enhancing the reliability of the battery cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode assembly is positioned closer to the housing wall to increase capacity, then the amount of active substance near the wall increases, but the pulling effect on the pressure relief structure intensifies, increasing the risk of damage and liquid leakage
Solution Approach 1:
The patent applies local quality by creating an asymmetric arrangement where only specific electrode plate layers (first preset electrode plate layers) are positioned at different distances from the housing wall. The at least one first preset electrode plate layer has its first active substance layer positioned farther from the first wall compared to the second active substance layer, creating a local variation in electrode-housing spacing. This localized asymmetric positioning reduces the amount of active substance near the wall where the pressure relief structure is located, thereby reducing the pulling effect on this structure while maintaining overall high capacity through other properly positioned electrode layers.
2Reliability
If the electrode assembly is positioned farther from the housing wall to reduce pulling effect on pressure relief structure, then the reliability of pressure relief structure improves, but the amount of active substance near the wall decreases, reducing the lithium ion accommodation capacity
Solution Approach 1:
The patent resolves this contradiction by applying local quality through selective positioning. Instead of uniformly positioning all electrode layers far from the wall (which would reduce capacity), only the first preset electrode plate layers are positioned with their first active substance layers farther from the first wall. This localized adjustment specifically reduces the pulling effect on the pressure relief structure while other electrode layers maintain optimal positioning for capacity, thus achieving both reliability improvement and capacity preservation.
Solution Approach 2:
The patent applies segmentation by dividing the electrode assembly into different functional zones: first preset electrode plate layers that are positioned farther from the first wall to protect the pressure relief structure, and other electrode plate layers that can be positioned closer to maximize capacity. This segmentation allows different regions of the electrode assembly to serve different purposes - some regions prioritize structural protection while others prioritize electrochemical performance.
Data Source
AI summary
A battery cell, a battery, and an electric device are disclosed. The battery cell includes a casing with a first wall, a pressure relief structure disposed on the first wall, and an electrode assembly accommodated in the casing. The electrode assembly comprises multiple electrode sheet layers stacked in a first direction, the layers including cathode and anode electrode sheet layers. Each electrode sheet layer includes an electrode sheet body, a first active material layer, and a second active material layer disposed on opposite sides of the sheet body. At least one electrode sheet layer is configured as a first preset electrode sheet layer, in which the distance between its first active material layer and the first wall is greater than the distance between its second active material layer and the first wall. The first direction is parallel to a plane of the first wall.