Electrical Cell Module Assembly for Variable Stack Lengths
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Solution Overview
Problem
Existing electrical cell modules face issues with inconsistent stack lengths due to dimensional variations in cells, leading to poor fit, increased manufacturing costs, and potential cell damage from variable compression, and require complex grading processes to ensure consistent stack length.
Innovation Solution
An electrical cell module design with opposing module end plates and cell stacks, each applying consistent compressive force within a predetermined range, allowing for variable stack lengths and ensuring accurate mounting points, using support plates and guide elements for alignment and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cells are stacked to form cell stacks with many cells (10 or more), then the energy storage capacity increases, but the aggregate tolerance in stack length increases (around +/â3.6 mm for 12 cells), leading to poor fit within housing unit or vehicle chassis
Solution Approach 1:
The patent changes the parameter of stack length by introducing adjustable spacers that can be positioned at different locations along the stack. This allows the effective stack length to be adjusted within the tolerance range (+/â3.6 mm) to achieve a proper fit within the housing unit or vehicle chassis, while maintaining the same number of cells for energy storage capacity.
2Manufacturing precision
If cell stacks are compressed to a fixed stack length to ensure accurate fit, then the fit within housing unit or vehicle chassis improves, but the compression force on cells becomes variable due to underlying variability in cell thickness, risking cell damage or suboptimal operation
Solution Approach 1:
The patent introduces spacers as intermediary elements between the compression force and the cells. These spacers are positioned at specific locations along the stack and can be removed or adjusted to control the compression force applied to the cells. This allows the stack length to be fixed for accurate fit while preventing excessive or variable compression forces that could damage cells or reduce their operational efficiency.
3Manufacturing precision
If compressible spacers are used between cells to accommodate thickness tolerances, then the stack length variability is reduced, but different compressive forces are applied to different cells, increasing the risk of cell over-compression or under-compression
Solution Approach 1:
The patent extracts the compression function from the spacers themselves and separates it into two distinct functions: (1) spacers that maintain stack length and positioning, and (2) a separate compression mechanism (such as end plates or compression bars) that applies uniform compressive force to all cells. This separation allows the spacers to accommodate thickness tolerances without creating variable compression forces on individual cells.
4Manufacturing precision
If cell grading is performed to pair minimum thickness cells with maximum thickness cells, then stack length consistency improves, but manufacturing time and costs increase due to additional measurement and sorting processes
Solution Approach 1:
The patent enables the assembly process to self-adjust to cell thickness variations through the use of adjustable spacers and compression mechanisms. Instead of requiring pre-grading of cells to achieve consistency, the assembly structure itself accommodates the variations, allowing cells to be assembled in any order while still achieving consistent stack lengths and proper compression forces.
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 assembly with consistent compressive force, reduces manufacturing time and costs, and improves cell module reliability by accommodating varying cell dimensions, ensuring accurate fit and reduced cell damage.
Implementation Method 1
the pair of stack end plates apply to the series of cells a compressive force along the longitudinal axis
Data Source
AI summary
The invention relates to an electrical cell module comprising: an opposing pair of module end plates spaced apart along a longitudinal axis; a first cell stack; and a second cell stack. Each cell stack comprises: a series of cells stacked along the longitudinal axis, and a pair of stack end plates at opposing ends and configured to be fixed to one another in an assembled position to apply to the series of cells a compressive force along the longitudinal axis, and define a stack length. The compressive forces are within a predetermined operable range. Each opposing pair of module end plates is fixedly engaged, in a use position, with one corresponding stack end plate of each cell stack so the module end plates are spaced apart from one another along the longitudinal axis by a predetermined distance, and the first stack length is different to the second stack length.