Battery Module Case Assembly for Airtightness Under Thermal Deformation
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Solution Overview
Problem
Conventional battery modules have incomplete airtight structures, leading to the discharge of gas or flame outside during ignition, causing rapid fire spread among adjacent modules due to thermal deformation and inadequate sealing.
Innovation Solution
A battery module design featuring a clad metal module case with a top plate that is press-fitted and welded to the case body, ensuring airtightness through a double-layer structure where the outer layer is made of a lower melting point metal and the inner layer of a higher melting point metal, such as stainless steel, providing enhanced heat resistance and mechanical rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a groove structure with sealing material is used to join the U frame and top plate, then assembly ease is improved, but airtightness deteriorates because the sealing material melts and disappears at high temperatures
Solution Approach 1:
The module housing uses a composite structure combining aluminum-based metal (for lightweight and corrosion resistance) with steel (for high-temperature strength). The steel plate is coupled to the aluminum-based U frame through a press-fitted groove structure that maintains airtightness even at high temperatures, preventing the sealing material melting problem of single-material designs.
Solution Approach 2:
The invention changes the material parameters by introducing steel with higher melting point and thermal stability into the aluminum-based structure. This parameter change allows the housing to maintain structural integrity and airtightness at high temperatures during battery ignition, solving the problem of sealing material degradation.
2Weight of moving object
If the module housing is made of single aluminum-based metal, then weight is reduced and corrosion resistance is improved, but heat resistance deteriorates due to thermal deformation at high temperatures
Solution Approach 1:
The module housing employs a composite structure where the U frame is made of aluminum-based metal (providing lightweight and corrosion resistance) and the top plate is made of steel (providing high-temperature strength). This composite approach allows the housing to maintain both low weight and high heat resistance, preventing thermal deformation during battery ignition.
3Ease of manufacture
If plastic injection molding is used for front and rear covers, then manufacturing cost is reduced, but airtightness deteriorates because welding cannot be applied to plastic assemblies
Solution Approach 1:
The front and rear covers use a composite structure combining plastic injection-molded components with metal reinforcement plates. The metal plates are welded to ensure airtightness at critical joints, while the plastic portions maintain manufacturing cost efficiency. This hybrid approach solves the contradiction between low-cost plastic molding and airtight welding requirements.
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 design prevents the discharge of gas or flame outside for a certain period during ignition, maintaining airtightness and reducing the risk of fire spread by ensuring the module case remains intact under high temperatures.
Implementation Method 1
the module housing is made of a single metal of aluminum-based (melting point of about 660 degrees) in the conventional battery module, and thus there is a problem in that airtightness may not be maintained due to thermal deformation of the U frame or top plate at a certain temperature or higher during ignition
Implementation Method 2
the entire outer circumference of the portion where the open end of the case body and the edge of the top plate are in contact with each other is welded
Data Source
AI summary
A battery module includes at least one battery cell; and a module case composed of a case body having an inner space for accommodating the battery cell and an open end on the upper side; and a top plate that covers the upper side of the open case body and is coupled to the upper portion of the case body. The open end of the case body has an assembly guide protrusion protruding upward from the surface thereof, and the top plate has an assembly guide hole that is press-fitted with the assembly guide protrusion at an edge thereof, and the entire outer circumference of the portion where the open end of the case body and the edge of the top plate are in contact with each other is welded.