Battery Pack Pressure Relief Cavities to Contain Thermal Runaway
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Solution Overview
Problem
Conventional battery packs experience chain thermal runaway and fires due to communication between battery cells, where a single cell's thermal runaway can trigger others, leading to a complete pack failure.
Innovation Solution
A battery pack design featuring a housing with independently arranged grooves and pressure relief cavities for each sub-module, where pressure relief valves communicate directly with these cavities, preventing flame and high-temperature gas spread between cells, and includes a sealing plate, rib structure, and explosion-proof valves to manage pressure and airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure relief valves at the bottom of battery cells communicate together through a common cavity, then the structure is simple and easy to manufacture, but thermal runaway in one cell spreads to other cells causing chain thermal runaway
Solution Approach 1:
The patent divides the pressure relief system into independent segments by providing separate pressure relief cavities for each battery cell or sub-module. Each cavity is independently sealed and equipped with its own pressure relief valve, preventing the spread of thermal runaway between cells. This segmentation approach directly addresses the chain thermal runaway problem while maintaining reasonable structural complexity.
Solution Approach 2:
The patent extracts the pressure relief function from a shared common cavity and assigns it to individual cavities for each battery cell. By taking out the pressure relief capability from the communal structure and giving it to each cell separately, the system prevents cross-contamination of thermal runaway while preserving the essential pressure relief function for each cell.
2Reliability
If independent pressure relief cavities are provided for each sub-module, then thermal runaway is contained within one cell, but the structure becomes more complex
Solution Approach 1:
The patent implements a nested structure where pressure relief cavities are integrated within the housing structure, and sealing plates are nested within the cavities. The ribs extend into the cavities to provide additional sealing and structural support. This nesting approach allows multiple functional elements to be compactly arranged, reducing overall structural complexity while maintaining independent pressure relief for each sub-module.
Solution Approach 2:
The housing structure serves multiple functions: it provides mechanical support, contains the battery cells, and houses the independent pressure relief cavities. The sealing plates perform both sealing the cavities and providing mounting surfaces for pressure relief valves. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall structural complexity.
3Reliability
If sealing plates with through holes are used to cover grooves, then pressure relief is directed properly, but manufacturing precision requirements increase
Solution Approach 1:
The patent merges the sealing plate and the pressure relief valve mounting functions into a single integrated component. The through holes in the sealing plate are positioned to align with both the grooves in the housing and the pressure relief valve openings. This integration reduces the number of separate components and simplifies the alignment requirements, as the sealing plate itself defines the alignment reference for both the groove coverage and valve connection.
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 design effectively prevents the spread of thermal runaway from one cell to others, enhancing the safety and reliability of the battery pack by containing flames and high-temperature gases within each sub-module's pressure relief system.
Implementation Method 1
when one battery cell in the battery pack occurs thermal runaway, a pressure relief valve at the bottom of the battery cell under the thermal runaway condition emits a combustible gas and a flame
Implementation Method 2
a pressure relief cavity is provided between a bottom surface of each of the plurality of sub-modules and a corresponding one of the plurality of first grooves... preventing flame and high-temperature gas spread between cells
Data Source
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AI summary
A battery pack is provided, including a housing and a battery module. The housing includes a bottom plate and a side wall plate connected to peripheral sides of the bottom plate, wherein the bottom plate and the side wall plate are enclosed to form an accommodating cavity, and a surface of the bottom plate which faces towards the accommodating cavity forms a plurality of first grooves independently arranged. The battery module is located at the accommodating cavity, wherein the battery module includes a plurality of sub-modules, a pressure relief cavity is provided between a bottom surface of each of the plurality of sub-modules and a corresponding one of the plurality of first grooves, the sub-modules each include battery cells, bottom surfaces of the battery cells are provided with respective pressure relief valves, and openings of the pressure relief valves communicate with the pressure relief cavity.