Battery Pack Binding Load Control for Gas Release Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing battery pack manufacturing methods face instability due to excessive binding load causing plastic deformation and increased spring constant, leading to decreased binding force during temperature changes or charging/discharging, which affects the accommodation state of battery cells and the pack as a whole.
Innovation Solution
A method for manufacturing a battery pack that involves setting a specific binding load by calculating the ratio of positive and negative electrode active material masses to pore volumes and separator pores, ensuring the pressure applied is sufficient to release gas without overcompressing the electrode body, thus maintaining a stable binding state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a large binding load is applied to release gas from the electrode body, then gas release is improved, but the case and electrode body undergo plastic deformation and the spring constant increases
Solution Approach 1:
The patent applies a specific binding load parameter range (0.2 to 0.5 MPa) to optimize the balance between gas release and preventing plastic deformation. By controlling the pressure parameter within this range, the method achieves effective gas evacuation while maintaining the elastic properties of the case and electrode body, thus resolving the contradiction between gas release and spring constant maintenance
2Stability of the object's composition
If the spring constant of the battery cell is high, then structural stability is improved, but the binding load decreases greatly during contraction due to temperature changes or charging/discharging
Solution Approach 1:
The patent introduces a dynamic binding load application method where the binding load is applied progressively during the charging process rather than being fixed. This allows the binding force to adapt to the changing volume and pressure conditions of the electrode body, maintaining effective contact and binding force throughout charging/discharging cycles and temperature variations, thus resolving the contradiction between structural stability and binding force maintenance
3Object-generated harmful factors
If excessive pressure is applied to the electrode body, then gas release is improved, but internal resistance increases due to plastic deformation
Solution Approach 1:
The patent optimizes the binding load parameter to a specific range (0.2 to 0.5 MPa) that is sufficient to compress gas bubbles out of the electrode body pores without causing plastic deformation of the case or electrode structure. This precise parameter control achieves effective gas removal while preserving the electrical conductivity and low internal resistance of the electrode body, resolving the contradiction between gas release and internal resistance
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 ensures appropriate gas release and prevents excessive pressure, maintaining a stable binding state and reducing internal resistance, while limiting the increase in spring constant and internal resistance of the battery cell.
Implementation Method 1
the binding bands apply a fixed binding load to the battery cells and the spacers in the direction in which the battery cells are arranged next to one another
Implementation Method 2
the case and the electrode body may plastically deform and increase the spring constant of the battery cell
Implementation Method 3
if the battery cell undergoes contraction due to temperature changes or charging/discharging
Data Source
AI summary
A method for manufacturing a battery pack includes forming a positive electrode plate; forming a negative electrode plate; forming an electrode body; forming a battery cell; applying a binding load to battery cells; and initially charging the battery cells. When “A mg/cm2” represents a mass of a positive electrode active material on the positive electrode substrate, “C cm3/cm2” represents a volume of pores in the positive electrode substrate, “B mg/cm2” represents a mass of a negative electrode active material on the negative electrode substrate, “D cm3/cm2” represents a volume of pores in the negative electrode substrate, “E cm3/cm2” represents a volume of pores in the separator, and “F N/mm2” represents pressure applied to an opposing portion of a case of the electrode body facing a flat surface of the electrode body, a value of (A+B)/{(C+D+E)/F} is between 1300 and 3000, inclusive.