Bipolar Battery Sealing Structure for Detection Line Thickness
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Solution Overview
Problem
The deformation of current collectors due to contraction of sealing members and the local increase in thickness of electrode stacks in bipolar secondary batteries, particularly when detection lines are stacked, are not adequately addressed in existing technologies.
Innovation Solution
The electric power storage module employs a sealing body composed of resin sealing members and spacers to surround the electrode stack, with detection lines led out from an outer side face, allowing for elastic deformation absorption and reduced thickness increase while minimizing deformation of the current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sealing member is made thinner to reduce contraction influence on the current collector, then the deformation of the current collector is suppressed, but the ability to absorb thickness increase of the detection line is reduced
Solution Approach 1:
The sealing structure is divided into multiple sealing members arranged in series along the stacking direction. Each sealing member has a reduced thickness that minimizes contraction influence on the current collector, while the collective arrangement of multiple sealing members provides sufficient total thickness to absorb the thickness increase of detection lines at joint portions.
Solution Approach 2:
The sealing members are positioned at specific locations where thickness absorption is needed, particularly at joint portions of detection lines. The local arrangement and configuration of sealing members are optimized to provide thickness absorption capability exactly where the detection line thickness increases, rather than uniformly distributing thickness throughout the entire sealing structure.
2Reliability
If detection lines are joined to current collectors in stacked electrodes, then voltage detection capability is achieved, but the thickness of the stack locally increases at joint portions
Solution Approach 1:
The sealing members act as intermediary elements between the detection lines and the external environment. These sealing members are positioned to cover the joint portions where detection lines are joined to current collectors, and their thickness is designed to absorb the local thickness increase caused by the detection line joints, thereby maintaining overall stack thickness uniformity while preserving voltage detection capability.
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 effectively suppresses local thickness increases and deformation of the current collector, enhances sealability, and prevents short circuits and welding defects, ensuring reliable operation and improved manufacturing efficiency.
Implementation Method 1
there is a possibility that deformation such as wrinkling occurs in the current collector due to contraction of the sealing member after welding due to a difference between a linear expansion coefficient of the sealing member and a linear expansion coefficient of the current collector
Implementation Method 2
there is a possibility that thicknesses of the detection lines are added at a joint portion of the detection lines so that a thickness of the stack locally increases
Implementation Method 3
it is conceivable to increase the thickness of the sealing member to secure the amount of elastic deformation of the sealing member and absorb an increase in the thickness of the detection line by the elastic deformation of the sealing member
Data Source
AI summary
An electric power storage module including: an electrode stack including a plurality of electrodes each including a current collector and a detection line joined to the current collector; and a sealing body provided on the electrode stack to surround the electrode stack and configured to seal an internal space between the current collectors adjacent to each other, in which the sealing body includes a plurality of sealing members made of a resin and welded to the plurality of electrodes, respectively, a plurality of spacers each of which is made of a resin, disposed between the sealing members adjacent to each other, and forms the internal space together with each of the sealing members, and an outer side face formed by welding the sealing members and the spacers to each other.