Battery Module Welding Fatigue Testing Under Cell Swelling Pressure
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Solution Overview
Problem
Conventional fatigue failure verification devices for battery module housing welding portions struggle to replicate actual swelling conditions, particularly in small battery modules, due to difficulties in applying uniform force and limited hydraulic units.
Innovation Solution
A fatigue failure verification device featuring a module housing with a central main flexible tube, sub-flexible tubes, and a pump to control fluid pressure, along with buffer pads and displacement sensors, which simulates the expansion and contraction of battery cells by applying adjustable pressure in multiple directions, mimicking actual swelling environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a small hydraulic unit is installed in the central portion of a battery cell stack, then the device can simulate swelling of battery cells, but it is difficult to apply a uniform force to the entire area of the battery cell and sufficient force cannot be applied when the battery module size is small
Solution Approach 1:
The single central hydraulic unit is segmented into multiple hydraulic units distributed at different positions (central, upper, lower, side portions) within the housing. This segmentation allows each unit to apply force to specific regions of the battery cell, achieving uniform force distribution across the entire cell area while maintaining system simplicity.
Solution Approach 2:
The force application transitions from a single-point central hydraulic unit to a multi-dimensional distributed arrangement of hydraulic units throughout the housing volume. This spatial distribution across multiple dimensions enables comprehensive force application to the entire battery cell surface area.
2Reliability
If conventional verification devices are used, then the structure is simple, but they cannot provide conditions similar to actual swelling environment in battery modules
Solution Approach 1:
Different regions of the housing are equipped with hydraulic units having different characteristics (central, upper, lower, side units) to replicate the localized swelling behavior of battery cells in different areas. This local differentiation enhances simulation accuracy while maintaining overall structural simplicity through modular design.
3Force
If only a central hydraulic unit is used, then the device structure is simple, but uniform force cannot be applied to the entire battery cell area
Solution Approach 1:
The hydraulic system is segmented into multiple independent units positioned at strategic locations (central, upper, lower, side portions) to distribute force uniformly across the battery cell. Each segment operates independently but coordinates to achieve overall uniform force application.
Solution Approach 2:
Multiple hydraulic units are merged into a coordinated system where central, upper, lower, and side units work together to achieve uniform force distribution. The combination of these units creates a comprehensive force application system that covers the entire battery cell area.
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
This configuration allows for the appropriate design of welding portions by replicating the actual swelling environment of battery modules, ensuring effective simulation of fatigue accumulation and damage prevention.
Implementation Method 1
a pump configured to adjust a pressure applied by the main flexible tube to the battery cell by supplying a fluid to the main flexible tube
Implementation Method 2
at least one main flexible tube located in a central portion of the cell stack... a pump configured to adjust a pressure applied by the main flexible tube to the battery cell
Data Source
AI summary
Discussed is a fatigue failure verification device that can include a module housing including a welding portion, a cell stack including a plurality of battery cells accommodated in the module housing, at least one main flexible tube located in a central portion of the cell stack in a stack direction of the cell stack, a main flexible tube frame in which the at least one main flexible tube is accommodated. The main flexible tube frame can include a pair of opening portions formed on opposite sides so that the at least one main flexible tube faces the plurality of battery cells, and a pump can be provided, which is configured to adjust a pressure applied by the at least one main flexible tube to the plurality of battery cells by supplying a fluid to the at least one main flexible tube.