Cell Module Assembly for Variable Stack Length Compression
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Solution Overview
Problem
Existing electrical cell modules face challenges with inconsistent stack lengths due to dimensional variations in cells, leading to poor fit, excessive compression, and increased manufacturing costs, as well as inefficiencies in mounting and compressive force application.
Innovation Solution
The electrical cell module design includes opposing module end plates that apply consistent compressive force to cell stacks of varying lengths, using support plates and guide elements to ensure precise alignment and secure mounting, allowing for adaptable assembly and reduced manufacturing time and costs.
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 (variance of around +/-3.6mm for 12 cells), leading to poor fit within the vehicle chassis or housing unit
Solution Approach 1:
A spacer is introduced as an intermediary component between cells in the stack. The spacer includes a compressible portion that deforms to accommodate variations in cell thickness, thereby maintaining a consistent overall stack length despite aggregate tolerances accumulating across multiple cells
Solution Approach 2:
The spacer's compressible portion changes its physical parameter (compression distance) in response to variations in cell thickness. By allowing the spacer to compress by varying amounts, the system compensates for cumulative tolerance errors and maintains a consistent stack length parameter
2Manufacturing precision
If compressible spacers are used between cells to accommodate thickness tolerances, then the stack length consistency improves, but the compression force on each cell becomes non-uniform, risking cell damage or suboptimal performance
Solution Approach 1:
The spacer is designed to perform multiple functions simultaneously: it accommodates thickness variations to maintain stack length consistency while also distributing compression force uniformly across all cells through its specific structural design
Solution Approach 2:
The spacer has different structural properties at different locations - the compressible portion is designed with specific material or structural characteristics that allow it to deform in a controlled manner, creating localized compliance zones that enable uniform force distribution while accommodating dimensional variations
3Manufacturing precision
If cells are graded and paired by thickness to ensure consistent stack length, then the stack length variance reduces, but the manufacturing time increases and cell wastage increases for cells that do not provide suitable combinations
Solution Approach 1:
The grading and pairing process is eliminated by extracting the tolerance compensation function and placing it in the spacer component. This allows all cells to be used without selective pairing, reducing manufacturing time and cell wastage while maintaining stack length consistency
Solution Approach 2:
The spacer automatically compensates for thickness variations in each cell stack without requiring external intervention for cell grading or pairing. The system self-adjusts to accommodate any cell within the specified tolerance range, eliminating the need for time-consuming manual or automated cell sorting processes
4Reliability
If the housing unit is designed to accommodate cell stacks with aggregate tolerance, then the fit becomes unreliable requiring adaptations, but designing for tighter tolerances increases manufacturing complexity and cost
Solution Approach 1:
The spacer acts as a mediator between the cell stack and the housing unit, absorbing dimensional variations and ensuring a reliable fit without requiring complex housing adaptations. The housing can be designed with standard tolerances while the spacer compensates for cell stack variations
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 ensures consistent compressive force application across cell stacks, improves efficiency, reduces manufacturing time and costs, and facilitates reliable installation in vehicles, while accommodating a wider range of cell tolerances.
Implementation Method 1
the pair of stack end plates apply to the series of cells a compressive force along the longitudinal axis
Data Source
Figure 1
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AI summary
The present invention relates to an electrical cell module, particularly an electrical cell module including at least two cell stacks. A method of manufacturing the electrical cell module is also disclosed. The electrical cell module comprises: an opposing pair of module end plates spaced apart from one another along a longitudinal axis; a first cell stack; and a second cell stack. Each of the first cell stack and second cell stack comprises: a series of cells stacked along the longitudinal axis, and a pair of stack end plates, arranged at opposing ends of the series of cells, and configured to be fixed to one another in an assembled position. In the assembled position, the pair of stack end plates apply to the series of cells a compressive force along the longitudinal axis, and define a stack length of the respective cell stack. The compressive force applied to the first cell stack and the compressive force applied to the second cell stack are each within a predetermined operable range. The electrical cell module is configured so that each of the opposing pair of module end plates is fixedly engaged, in a use position, with one corresponding stack end plate of each of the first cell stack and the second cell stack. In the use position 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.