Insulating Oil Battery Module Layout for Direct Cooling and Sealing
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Solution Overview
Problem
Indirect water cooling methods for battery modules limit cooling performance and increase volume due to the need for external cooling devices, leading to energy density losses and potential oil leakage.
Innovation Solution
A battery module design that introduces insulating oil directly into a housing, allowing it to flow through a longitudinal passage between the battery cells and the housing, with a sealing mechanism to prevent leakage, using a sub-module with a cell stack, bus bar frames, and a housing structure that includes insulating oil inlets and outlets, along with sealing gaskets and binders to maintain airtightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If indirect water cooling method is used, then cooling performance is limited, but device complexity is reduced
Solution Approach 1:
The housing is integrated with cooling fins that directly contact the battery cells, merging the structural support function with the heat dissipation function. The insulating oil flows through passages formed within the housing itself, eliminating the need for separate external cooling devices and heat sinks, thereby improving cooling performance while maintaining device simplicity.
Solution Approach 2:
Insulating oil is introduced as an intermediary cooling medium that flows through the housing passages and directly contacts the cooling fins, which in turn contact the battery cells. This intermediary fluid enables efficient heat transfer from the battery cells to the housing without requiring complex external water cooling systems.
2Temperature
If separate heat sink is provided outside housing, then cooling passage is formed, but volume of battery module increases
Solution Approach 1:
The cooling fins and cooling passages are integrated into the housing structure itself, combining the housing with the heat dissipation system. This eliminates the need for separate external heat sinks and reduces the overall battery module volume while maintaining effective cooling through direct contact between the cooling fins and battery cells.
Solution Approach 2:
The cooling passages are nested within the housing structure, with the insulating oil flowing through channels formed inside the housing walls. The cooling fins are positioned within the housing to directly contact the battery cells, creating a nested arrangement that maximizes cooling efficiency within the available internal volume without increasing external dimensions.
3Temperature
If insulating oil is introduced directly into housing, then cooling performance improves, but risk of oil leakage increases
Solution Approach 1:
The insulating oil inlet and outlet are extracted as separate, dedicated components with defined connection points. The inlet passes through the housing to supply oil into the receiving space, while the outlet discharges oil from the receiving space. This extraction of fluid pathways as distinct elements allows for focused sealing design at specific interfaces, managing leakage risk while maintaining direct cooling effectiveness.
Solution Approach 2:
Sealing gaskets are employed at the interfaces where the insulating oil inlet and outlet pass through the housing, and at the connections between housing components. These flexible sealing elements accommodate thermal expansion and manufacturing tolerances while maintaining airtightness, preventing insulating oil leakage while allowing the housing to maintain its cooling function.
4Temperature
If insulating oil flows through longitudinal passage, then cooling efficiency increases, but sealing complexity increases
Solution Approach 1:
The sealing system is segmented into distinct sealing locations: sealing gaskets at the housing component interfaces, sealing at the insulating oil inlet passage, and sealing at the insulating oil outlet passage. This segmentation allows each sealing element to be optimized for its specific location and function, managing the complexity of maintaining airtightness throughout the longitudinal flow path while enabling efficient cooling.
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 enables efficient cooling of battery cells by ensuring smooth flow of insulating oil and prevents leakage, enhancing energy density and cooling performance while maintaining airtightness within the module.
Implementation Method 1
insulating oil introduced into a housing flows through a space between an edge of a battery cell and the housing to cool battery cells
Data Source
AI summary
A battery module including: a sub-module including a cell stack including a plurality of battery cells and cooling fins located between adjacent battery cells, front and rear bus bar frames coupled to first and second sides of the cell stack in a longitudinal direction of the cell stack, respectively; a housing including a main housing accommodating the sub-module, lower and upper covers covering a lower opening and an upper opening, respectively, of the main housing; an insulating oil inlet passing through a first side of the main housing in a longitudinal direction of the main housing and configured to supply insulating oil into a receiving space of the sub-module; and an insulating oil outlet passing through a second side of the main housing in the longitudinal direction of the main housing and configured to discharge the insulating oil from the receiving space of the sub-module.