Battery End Plate Structure for Rigid Cell Stack Compression
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Solution Overview
Problem
High-energy density battery systems face challenges in maintaining the relative positions of stacked rectangular battery cells due to deformation of end plates under strong cell reaction forces, leading to potential damage at connection points between bus bars and electrode terminals, while achieving both high strength and low weight is difficult with existing end plate structures.
Innovation Solution
The battery system employs end plates with a unique configuration featuring dual-side blocks and an intermediate block in a tapered groove, converting pressing forces into tensile stress on both surfaces, thereby enhancing flexural rigidity while reducing weight, and using high-strength metal plates for the outer and inner surfaces with a light material for the plate-shaped block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If end plates with high flexural rigidity are used to prevent deformation under strong cell reaction forces, then the relative positions of battery cells are maintained, but the weight and complexity of the end plate structure increase
Solution Approach 1:
The end plate is divided into multiple functional components: outer plate, inner plate, plate-shaped block, dual-side blocks, and intermediate block. Each component serves a specific function in distributing and converting the cell reaction force, allowing the structure to achieve high rigidity without requiring a single heavy monolithic plate
Solution Approach 2:
The patent changes the stress state parameter by converting compressive stress from the battery stack into tensile stress in the plates through the intermediate block's action in the tapered groove. This parameter transformation allows the use of lighter materials that perform well in tension while maintaining structural rigidity
2Stability of the object's composition
If binding force is increased to suppress battery cell expansion during charging and discharging, then cell position stability is improved, but cell reaction force on end plates increases causing deformation
Solution Approach 1:
The patent converts the harmful cell reaction force that causes end plate deformation into a useful tensile stress in the plates. The intermediate block, when pressed by the battery stack, moves in the tapered groove and applies tensile stress to the outer and inner plates, thereby utilizing the reaction force to enhance structural rigidity rather than overcome it
Solution Approach 2:
The end plate employs a composite structure combining multiple materials: high-strength metal plates for the outer and inner plates to withstand tensile stress, and light material for the plate-shaped block. This composite approach optimizes the strength-to-weight ratio while managing the cell reaction force
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 configuration effectively increases the flexural rigidity of the end plates, preventing deformation and maintaining the relative positions of battery cells, while achieving a lightweight and strong structure that efficiently converts pressing forces into tensile stress, thus reducing the risk of damage at connection points.
Implementation Method 1
the intermediate block pressed by the battery stack is press-fitted into the tapered groove and applies tensile stress to the outer plate and the inner plate via the dual-side blocks
Data Source
AI summary
A battery system includes: a battery stack including a plurality of rectangular battery cells that are stacked; end plate placed at both ends of the battery stack; and a binding bar that connects the end plates to fix the battery stack in a compressed state. End plate includes plates placed on both surfaces and plate-shaped block laminated between plates; plates include outer plate and inner plate; plate-shaped block includes dual-side blocks placed on both sides so as to be separated from each other and intermediate block placed in tapered groove between dual-side blocks; the tapered groove has a taper shape that gradually increases in width from an outside to an inside of the end plate. The intermediate block is placed in facing surfaces of the tapered groove in a slidable manner; the dual-side blocks are fixed to the plates; and intermediate block pressed by battery stack is press-fitted into tapered groove and end plate applies tensile stress to outer plate and inner plate via dual-side blocks.