Power Battery Cap Assembly Flow Redirection

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Solution Overview

Problem

The existing cap assemblies for power batteries face issues with electrolyte injection, where the high-pressure electrolyte can cause deformation and short circuits due to direct impact on the electrode assembly, leading to safety concerns.

Innovation Solution

A cap assembly with a blocking member that redirects the electrolyte flow, reducing the impact force on the electrode assembly by changing the flow direction and incorporating a vent plate with a specific surface area ratio to manage pressure, thereby preventing direct axial flow and potential short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high pressure electrolyte injection is used to increase injection efficiency, then injection speed is improved, but the impact force on the electrode assembly increases causing deformation and short circuit

Engineering Contradiction:
Improveelectrolyte injection efficiencyVSAvoidimpact force on electrode assembly
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a cap plate as an intermediary component between the electrolyte injection system and the electrode assembly. The cap plate includes a liquid injection hole that redirects the electrolyte flow path, and a blocking member that further modifies the flow direction. This intermediary structure allows high-pressure injection to proceed efficiently while preventing the electrolyte from directly impacting the electrode assembly, thus resolving the contradiction between injection efficiency and impact force reduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If electrolyte flows directly along the injection hole axis, then injection process is simple, but the flow rate is high causing large impact force on the electrode assembly

Engineering Contradiction:
Improveinjection structure simplicityVSAvoidimpact force on electrode assembly
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent segments the electrolyte flow path into multiple directional changes using the cap plate structure. The liquid injection hole is positioned at an angle to the axis, and the blocking member creates additional flow redirection. This segmentation of the flow path into discrete directional changes reduces the linear flow velocity and impact force while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the flow direction from a single axial dimension to multiple dimensions by positioning the liquid injection hole at an angle and using the blocking member to redirect flow. This dimensional change in the flow path causes the electrolyte to discharge in a direction away from the electrode assembly, reducing impact force while adding only minimal structural complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3522250B1Cap assembly and power battery
Publication Date: 2021.05.26 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
  • EP3522250B1 patent drawingFigure 1
  • EP3522250B1 patent drawingFigure 2~5
  • EP3522250B1 patent drawingFigure 6

AI summary

The present disclosure relates to a cap assembly (1) and a power battery. The cap assembly (1) comprises a cap plate (11) including a top surface, a bottom surface opposed to the top surface in a thickness direction (X) and a liquid injection hole (111) penetrating through the cap plate (11) from the top surface to the bottom surface, the liquid injection hole (111) having an inlet provided on the top surface and an outlet provided on the bottom surface; and a blocking member (2) provided on the bottom surface, a projection of the blocking member (2) in the thickness direction at least partially covers the outlet, wherein a fluid channel (3) is formed between the blocking member (2) and the cap plate (11), and the fluid channel (3) communicates with the outlet of the liquid injection hole (111). In the case that the cap assembly (1) is applied to the power battery, the flow direction of the electrolyte can be changed and the impact force applied on the end portion of the electrode assembly (5) can be reduced during electrolyte injection.