Prismatic Battery Vent Layout to Prevent Safety Valve Blockage
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Solution Overview
Problem
Safety valves in prismatic power storage devices, such as lithium ion secondary batteries, can become blocked by fragments of the electrode body during a nail penetration test, leading to insufficient gas release and potential internal pressure buildup.
Innovation Solution
A prismatic power storage device with multiple safety valves of varying operating pressures is designed, including a first safety valve in the central region and additional safety valves on either side, which are operated at higher pressures, and terminal members to intercept flying fragments, ensuring effective gas release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single safety valve is provided in the central region of the lid, then gas can be released at relatively low operating pressure, but the safety valve may become blocked by fragments of the electrode body
Solution Approach 1:
The single safety valve is divided into multiple safety valves (first, second, and third safety valves) positioned at different locations on the lid. Each valve has different operating pressures, creating a segmented pressure release system that reduces the risk of complete blockage.
Solution Approach 2:
The safety valves are arranged in different spatial dimensions on the lid - the first valve in the central region, and the second and third valves on opposite sides in the longitudinal direction. This spatial distribution ensures that fragments traveling in straight lines from the electrode body are less likely to block all valves simultaneously.
2Reliability
If multiple safety valves with different operating pressures are provided, then the risk of complete blockage is reduced, but the device complexity increases
Solution Approach 1:
Each safety valve is assigned a specific local function with different operating pressures - the first valve operates at lower pressure in the central region, while the second and third valves operate at higher pressures on the sides. This local differentiation optimizes gas release at various pressure stages without requiring excessive valves.
3Reliability
If the first safety valve is positioned in the central region, then gas can be released at lower pressure, but fragments from electrode body cracks are more likely to reach and block this valve
Solution Approach 1:
The safety valve system is segmented into multiple valves with different spatial positions and operating characteristics. The first valve handles low-pressure release centrally, while secondary valves positioned elsewhere provide backup at higher pressures, distributing the blockage risk across multiple components.
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 device effectively prevents safety valve blockage by fragments, ensuring timely and complete gas release, thereby maintaining safe internal pressure even after a short circuit.
Implementation Method 1
a first safety valve provided in a central region in the longitudinal direction, between the positive-electrode insert hole and the negative-electrode insert hole, the first safety valve being to be opened at a first operating pressure; a second safety valve provided on the one side in the longitudinal direction relative to the central region, the second safety valve being to be opened at a second operating pressure higher than the first operating pressure
Data Source
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AI summary
A prismatic power storage device (1; 101) includes a case (4) having a case body (5) and a rectangular plate-shaped lid (6;106), an electrode body (2) housed in the case (4), a positive terminal member (7;107) extending out through a positive-electrode insert hole (6p,106p) provided in the lid (6;106), and a negative terminal member (8;108) extending out through a negative-electrode insert hole (6n;106n). The lid (6;106) includes a first safety valve (6s1;106s1) provided in a center (6C;106C) of the lid (6;106) and to be opened at a first operating pressure (P1), a second safety valve (6s2;106s2) provided on one side (LH1) relative to a central region and to be operated at a second operating pressure (P2) higher than the first operating pressure (P1), and a third safety valve (6s3;106s3) provided on the other side (LH2) relative to the central region and to be operated at a third operating pressure (P3) higher than the first operating pressure (P1).