Wound Electrode Battery Pack Pressure Layout for Gas Discharge
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Solution Overview
Problem
Conventional battery packs with wound electrode bodies face issues of gas retention and metal precipitation due to inadequate pressure distribution, leading to inhomogeneous charging and discharging reactions during high-rate charging and discharging.
Innovation Solution
A battery pack design where the wound electrode body is pressed by a spacer that covers 80% or more of the curved regions' area in a band shape along the winding axis and 20% to 50% of the flat region's area, ensuring gas discharge and preventing metal precipitation by maintaining pressure homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressing force is increased to prevent metal precipitation, then the charging and discharging reaction becomes more uniform, but the gas generated inside the electrode body cannot be discharged
Solution Approach 1:
The pressing member creates local quality differences by applying stronger pressing forces in the winding axis direction (where gas discharge is needed) compared to the radial direction (where reaction uniformity is needed). This localized differentiation allows simultaneous achievement of metal precipitation prevention and gas discharge
Solution Approach 2:
The invention modifies the pressing force parameters by establishing an asymmetric pressing regime: higher pressing force along the winding axis facilitates gas migration and discharge, while controlled radial pressing maintains reaction uniformity and prevents metal precipitation
2Object-generated harmful factors
If the pressing on the flat region is reduced to allow gas discharge, then the gas can escape more easily, but the charging and discharging reaction becomes inhomogeneous
Solution Approach 1:
The pressing member implements local quality differentiation by applying selective pressing forces: reduced radial pressing (to enable gas discharge) combined with enhanced winding axis pressing (to maintain reaction homogeneity through controlled compression). This spatial differentiation of pressing quality resolves the contradiction
Solution Approach 2:
The invention changes the pressing force parameters by creating an asymmetric pressing field: lower radial pressing forces allow gas to escape while higher axial pressing forces maintain sufficient contact between electrode layers, ensuring reaction homogeneity despite reduced radial compression
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 design effectively suppresses gas retention and metal precipitation, enhancing the battery's durability and maintaining high-rate charging capabilities by ensuring uniform pressure distribution and gas discharge.
Implementation Method 1
a space extending from a center part to an end part of the wound electrode body in a winding axis direction is formed between the part facing the flat region and the pressing member
Data Source
AI summary
A battery pack disclosed herein includes a wound electrode body, a battery case, and a pressing member. The battery case includes a pair of first side walls. The wound electrode body includes a flat region and a pair of curved regions and is disposed inside the battery case in a manner that the flat region faces the first side wall. In at least one of the pair of first side walls, 80% or more of the entire parts facing the pair of curved regions including border parts with the flat region is pressed in a band shape by the pressing member, 20 to 50% of the entire part facing the flat region is pressed by the pressing member, and a space extending from a center part to an end part in a winding axis direction is formed between the part facing the flat region and the pressing member.