Battery Module Frame and Compression Pads for Uniform Cell Pressure
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Solution Overview
Problem
Lithium secondary battery modules used in medium- and large-sized devices, such as electric vehicles, face challenges in maintaining life performance due to factors like swelling and uneven pressure distribution among battery cells, leading to capacity retention issues below the required 80% after 800 cycles.
Innovation Solution
A battery module design incorporating a module frame with side surface parts and compression pads, along with an adhesion part, to create a reserved space ratio of 3% or more per battery cell, ensuring uniform pressure distribution and stability through the use of compression pads and adhesion layers to absorb swelling and maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple battery cells are stacked together to form a battery module, then capacity and output are improved, but life performance deteriorates due to swelling and uneven pressure distribution
Solution Approach 1:
The patent introduces compression pads at specific locations between battery cells and side surface parts, creating localized compression zones that address swelling issues at critical points rather than uniformly throughout the module. This localized approach maintains cell contact and pressure distribution while allowing overall module expansion
Solution Approach 2:
The compression pads are pre-installed between battery cells and side surface parts before the cells swell. These pads act as cushioning elements that absorb and distribute the swelling pressure, preventing uneven stress concentration and maintaining stable pressure distribution throughout the battery module's operational life
2Quantity of substance
If battery cells are tightly packed to maximize space utilization, then energy density is improved, but pressure distribution becomes uneven leading to reduced capacity retention
Solution Approach 1:
The compression pads serve as intermediary elements between the battery cells and the rigid side surface parts. These pads mediate the interaction by providing a compliant interface that distributes pressure evenly across the cell surfaces, preventing direct rigid contact that would cause stress concentration and capacity degradation
3Strength
If compression force is increased to maintain structural stability, then structural integrity is improved, but swelling is restricted leading to reduced life performance
Solution Approach 1:
The compression pads provide dynamic compression force that adapts to the battery cells' swelling. Rather than applying fixed rigid compression, the pads compress elastically in response to cell expansion, maintaining appropriate contact pressure throughout the battery's operational life without restricting natural swelling that is necessary for long-term stability
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 effectively prevents deterioration in life performance by maintaining capacity retention at 80% or more after 800 cycles, ensuring stable operation and extended battery life by controlling pressure and structural stability within the battery module.
Implementation Method 1
at least one compression pad that is arranged at least at one place between adjacent battery cells among the battery cells or between the battery cell, located on the outermost side among the battery cells, and the side surface parts among the battery cells
Implementation Method 2
a battery module comprising: a battery cell stack formed by stacking a plurality of battery cells; a module frame that houses the battery cell stack
Data Source
AI summary
A battery module includes a battery cell stack formed by stacking a plurality of battery cells; a module frame that houses the battery cell stack and includes side surface parts, each covering both side surfaces of the battery cell stack along the stacking direction of the battery cells; and at least one compression pad that is arranged at least at one place between adjacent battery cells among the battery cells or between the battery cell, located on the outermost side among the battery cells, and the side surface parts among the battery cells, wherein a reserved space in the module frame is 3% or more, based on the stacking direction of the battery cells.