Electrode Stack Bonding via Gradient Polyethylene Particles
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Solution Overview
Problem
The high contact pressure required to bond electrode stacks together in battery manufacturing leads to increased manufacturing costs and difficulties in producing an inexpensive battery, as it necessitates large press apparatuses or reduced production rates.
Innovation Solution
An electrode stack design featuring a first separator with a higher density of polyethylene particles in its bonding layer, which enhances bonding strength even at reduced contact pressures, allowing for smaller press apparatuses and increased production rates, and a battery manufacturing method utilizing roller pressing for band-shaped composite bodies and flat pressing for electrode stacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high contact pressure is applied to bond electrode stacks together, then bonding strength is improved, but manufacturing cost increases and production rate decreases
Solution Approach 1:
The bonding layer is designed with non-uniform particle distribution, where the first region (facing the electrode plate) has a higher particle density than the second region (facing the separator body). This local quality variation enables effective bonding at lower contact pressures by concentrating bonding functionality where it is most needed, resolving the contradiction between bonding strength and production rate
Solution Approach 2:
The invention changes the particle density parameter within the bonding layer, creating a gradient structure where particle concentration varies by position. This parameter change allows the bonding layer to achieve sufficient bonding strength at reduced contact pressures, thereby increasing production rate without sacrificing bonding quality
2Strength
If high contact pressure is applied to bond electrode stacks together, then bonding strength is improved, but press apparatus size increases
Solution Approach 1:
By concentrating polyethylene particles in the first region of the bonding layer that contacts the electrode plate, the invention achieves effective bonding with localized particle density enhancement. This allows the use of smaller, less complex press apparatuses that do not need to generate excessively high contact pressures across the entire bonding interface
Solution Approach 2:
The gradient particle distribution changes the pressure distribution requirements, allowing bonding to occur effectively at lower overall contact pressures. This reduces the size and complexity requirements for the press apparatus while maintaining adequate bonding strength
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 approach reduces manufacturing costs by enabling effective bonding at lower pressures, downsizing press equipment, and increasing production rates, thereby making battery production more economical.
Implementation Method 1
a porous first bonding layer that is formed on a principal surface of the first separator body... containing first polyethylene particles and a binding agent that binds the first polyethylene particles with each other as well as binds the first polyethylene particles and the first separator body with each other
Implementation Method 2
these electrode stacks are pressed so as to be bonded together through the first bonding layer
Implementation Method 3
when this contact pressure is higher, the first polyethylene particles of the first bonding layer undergo more deformation, resulting in a larger contact area between the first bonding layer and the second electrode plate
Data Source
AI summary
Provided is an electrode stack formed by integrating a first separator, a first electrode plate, a second separator, and a second electrode plate. The first separator has a first separator body, and a first bonding layer that is formed on a principal surface of the first separator body and contains first polyethylene particles. The second separator has a second separator body, and a second bonding layer that is formed on a principal surface of the second separator body and contains second polyethylene particles. The number of particles of the first polyethylene particles per unit area of the first bonding layer is larger than the number of particles of the second polyethylene particles per unit area of the second bonding layer.