Battery Cover Breakpoint Forming for Precise Pressure Relief
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Solution Overview
Problem
Existing methods for creating a predetermined overpressure breaking point in battery covers for battery cell housings are inefficient in terms of precision and repeatability, leading to inconsistent pressure thresholds for safe pressure relief.
Innovation Solution
A forming tool comprising a die tool and a punch tool with a forming recess and stamp part, which allows for precise material flow and solidification to create a groove-shaped bead in the battery cover, accompanied by a hold-down arrangement to control deformation and a notching tool for further precision in setting the pressure threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing methods are used to create a predetermined overpressure breaking point in battery covers, then the process can be completed, but the precision and repeatability of pressure threshold formation is insufficient
Solution Approach 1:
The forming recess is pre-configured with specific geometric parameters (depth, width, shape) that predetermined the exact wall thickness reduction needed to achieve the target pressure threshold. The punch tool is pre-positioned and pre-loaded to apply force at the correct location with controlled magnitude, ensuring consistent breaking point formation across all battery covers without requiring post-adjustment.
Solution Approach 2:
The invention controls the forming process by precisely adjusting parameters including the forming recess depth (determining how much material is displaced), punch force magnitude, punch speed, and forming temperature. These parameter changes enable fine-tuning of the wall thickness reduction to achieve exact pressure thresholds while maintaining high repeatability across production batches.
2Manufacturing precision
If a forming recess is used to displace material and create a bead, then the breaking point can be formed, but control over material flow and deformation is insufficient
Solution Approach 1:
The forming recess is designed with non-uniform cross-sectional geometry, being wider at the opening and narrower at the base, creating different deformation zones. The punch tool features a localized contact area that concentrates force precisely where needed. This local quality differentiation enables controlled material flow into specific regions while maintaining overall tool design simplicity.
Solution Approach 2:
The forming process is segmented into distinct functional zones: the punch tool delivers concentrated force at the target location, the forming recess provides a controlled cavity for material displacement, and the battery cover structure itself acts as a third zone where the bead forms. This segmentation allows each component to be optimized independently for its specific function while maintaining overall system simplicity.
3Manufacturing precision
If the punch part is pressed into the battery cover to create a bead, then the overpressure breaking point is formed, but the remaining wall thickness control is insufficient
Solution Approach 1:
The forming recess geometry is designed to automatically self-regulate the material displacement process. As the punch presses into the battery cover, the expanding bead naturally fills the forming recess cavity, and the recess walls provide passive resistance that stops further deformation when the desired wall thickness reduction is achieved. This self-service mechanism eliminates the need for complex active control systems or multiple forming stages.
Solution Approach 2:
The forming recess is designed with sufficient volume to accommodate the complete bead formation process, allowing the punch to press in with adequate force to fully displace the required material. The recess dimensions are deliberately oversized relative to the minimum needed, ensuring that the forming process can complete fully without risk of insufficient deformation, while the geometry itself prevents excessive material displacement that would compromise structural integrity.
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
Enables the repeatable and precise formation of a predetermined overpressure breaking point in battery covers, ensuring consistent pressure thresholds with a tolerance of up to 1-2 bar, enhancing safety and reliability in pressure relief.
Implementation Method 1
During the forming of the battery cover, the punch part is pressed into the battery cover, whereby material from the battery cover flows into the forming recess
Data Source
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AI summary
The invention relates to a forming die (11) and a forming method for producing an overpressure predetermined breaking point (14) in a battery cover (10), wherein the overpressure predetermined breaking point (14) is particularly produced solely by forming. The forming die (11) has a stamp tool (23), a matrix die (24) and optionally a hold-down arrangement (25). A contact area (37) for the battery cover (10) to be formed is present on the matrix die (24), opposite which contact area a forming recess (38) is formed recessed in the matrix die (24). A stamp part is present on the stamp tool (23), the cross-section of which corresponds to a bead (15) to be produced in the battery cover (10). When the battery cover (10) is formed, the stamp part (32) is pressed into the battery cover (10), causing material of the battery cover (10) to flow into the forming recess (38). In doing so, the stamp part (32) approaches the forming recess (38) such that the remaining distance corresponds to a minimum wall thickness (w) at the overpressure predetermined breaking point (14).