Battery Pack Spacer Rib Structure for Electrolyte Retention
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Solution Overview
Problem
Nonaqueous electrolyte secondary battery packs face issues with electrolyte outflow due to expansion/shrinkage and volume changes during charge/discharge, leading to reduced high-rate performance, and existing methods to remove negative pressure after electrolyte injection are inefficient and prone to contamination.
Innovation Solution
Incorporating an internal pressure adjusting bag filled with gas within the battery case, along with a spacer having a convex rib to create confined and non-confined regions, and a gas supplying device to remove negative pressure after sealing, ensuring adequate electrolyte retention and preventing performance deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressing portion is formed on the spacer to prevent electrolyte outflow, then high-rate performance is maintained, but the structure becomes more complex and manufacturing becomes more difficult
Solution Approach 1:
The spacer is designed with a pressing portion only at the specific location where electrolyte outflow occurs during charge/discharge cycles. This localized pressing structure prevents electrolyte loss from the electrode assembly while maintaining simplicity in other areas of the spacer, thus resolving the contradiction between reliability and device complexity.
2Reliability
If negative pressure is removed after electrolyte injection by leaving the battery case opened, then electrolyte retention is improved, but production efficiency decreases and contamination risk increases
Solution Approach 1:
A communication hole is pre-formed in the battery case lid before sealing. This allows negative pressure to be removed after electrolyte injection by introducing gas through the hole, then the hole is sealed. This preliminary structure enables efficient pressure management without leaving the battery case opened, thus improving production efficiency while maintaining electrolyte retention and preventing contamination.
3Productivity
If the battery case is sealed immediately after electrolyte injection, then production efficiency is improved, but negative pressure remains causing electrolyte outflow and performance deterioration
Solution Approach 1:
A communication hole is pre-formed in the battery case lid before sealing. This allows the battery case to be sealed immediately after electrolyte injection for high production efficiency, while still enabling subsequent negative pressure removal through the hole without compromising electrolyte retention or high-rate performance.
4Stability of the object's composition
If a gas sealed bag is disposed inside the battery case to apply pressure to the electrode assembly, then electrode distance increase is inhibited, but the structure becomes more complex
Solution Approach 1:
The spacer is designed to serve multiple functions: it maintains the distance between adjacent battery cases, prevents electrolyte outflow through its pressing portion, and can also function as a pressure application structure against the electrode assembly. By making the spacer multi-functional, the need for a separate gas sealed bag is eliminated, thus maintaining electrode distance stability while reducing overall structure complexity.
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 solution effectively prevents electrolyte outflow and maintains high-rate performance by ensuring sufficient electrolyte retention within the battery pack, enhancing production efficiency and reducing contamination risks.
Implementation Method 1
gas supplying means for supplying, to an internal space of the battery case having been sealed, the gas held in the internal pressure adjusting bag
Implementation Method 2
the gas supplying means is a soluble part that is formed in at least a part of the internal pressure adjusting bag, and is made of a material soluble in the nonaqueous electrolyte
Data Source
AI summary
In a battery pack disclosed herein, a plurality of single cells are aligned in an alignment direction. In this battery pack, a spacer is disposed in a gap between adjacent ones of the single cells, and a convex rib is formed on the spacer. In a flat surface of each single cell, a region where the rib is in contact is a confined region, and a region where the rib is not in contact is a non-confined region. In the non-confined region within the battery case, an internal pressure adjusting bag filled with a gas is housed. In addition, gas supplying means (soluble part) for supplying the gas held in the internal pressure adjusting bag to an internal space of the battery case is provided. Thus, a negative pressure within the single cell is removed, and deterioration of high-rate performance otherwise caused by outflow of an electrolyte can be prevented.