Pouch Battery Cell Thermal Conductivity Measurement for Anisotropic Heat Flow
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Solution Overview
Problem
Conventional methods are inadequate for accurately measuring the thermal conductivity of pouch-type battery cells, which exhibit anisotropy due to their complex composition and arrangement of materials, making it difficult to evaluate their thermal characteristics.
Innovation Solution
An apparatus featuring a hot plate with a guarded hot plate, measuring plates, and cooling units arranged in a symmetrical structure to measure thermal conductivity in both upward and downward directions, using metal materials with high thermal conductivity and heat insulating members to minimize heat loss and promote one-dimensional heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional guarded hot plate method is used, then measurement can be performed on simple single-material test pieces, but it cannot accurately measure thermal conductivity of complex multi-material battery cells with anisotropic properties
Solution Approach 1:
The battery cell is divided into multiple material layers (positive electrode, negative electrode, separator, pouch) and thermal conductivity is measured for each layer separately by cutting ring-shaped specimens from each material layer, allowing accurate measurement of thermal properties in complex multi-material structures
Solution Approach 2:
Different measurement methods are applied to different material layers based on their specific thermal properties - the guarded hot plate method is used for materials requiring high precision measurement while considering the anisotropic nature of each layer, enabling localized accurate measurement tailored to each material's characteristics
2Measurement precision
If heat transfer occurs in multiple directions in complex battery cell structures, then thermal characteristics cannot be accurately evaluated, but restricting heat transfer to one dimension is difficult in anisotropic materials
Solution Approach 1:
Ring-shaped test pieces are extracted from each material layer of the battery cell, isolating specific materials for measurement. This extraction allows one-dimensional radial heat transfer to be achieved by eliminating complex three-dimensional heat paths present in the intact battery cell structure
Solution Approach 2:
The measurement approach transitions from attempting to measure three-dimensional heat transfer in the intact battery cell to measuring one-dimensional radial heat transfer in extracted ring-shaped specimens, simplifying the heat transfer path while maintaining measurement relevance to the actual battery structure
3Temperature
If pouch-type battery cells use high energy density designs, then temperature rise occurs inside the device, but conventional measurement methods cannot accurately capture the thermal conductivity needed to evaluate heat flow
Solution Approach 1:
The measurement system incorporates temperature control and measurement capabilities to evaluate thermal conductivity under conditions relevant to high energy density battery operation, allowing accurate determination of heat transfer properties that directly inform thermal runaway prevention strategies
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
Enables precise measurement of thermal conductivity in both directions, allowing for optimized design and placement of battery cells in electronic products, reducing the risk of thermal runaway and improving safety by accurately determining heat transfer ratios.
Implementation Method 1
The thermal conductivity refers to a value indicating the degree of heat conduction in an object, and is a value obtained by dividing the amount of heat flowing in a unit time past a unit area perpendicular to the flow of heat by a difference in temperature per unit length
Implementation Method 2
an auxiliary hot plate called a guarded hot plate is disposed around a hot plate so that heat flow can be accurately formed in one dimension in the sample, so that the hot plate has a constant temperature
Implementation Method 3
measuring the thermal conductivity by measuring the amount of heat flowing from the high temperature side to the low temperature side while accurately measuring the temperature on both sides of the sample
Data Source
AI summary
The present invention relates to a device for measuring the thermal characteristics of a pouch-type battery cell, specifically, the thermal conductivity of the battery cell, and a thermal conductivity measurement method using the same. When the battery cell thermal conductivity measurement device of the present invention is used, the thermal conductivity of a pouch-type battery cell exhibiting anisotropic thermal conductivity characteristics can be separated along each direction and measured, and thereby stability according to the thermal characteristics of a product, which uses a battery cell for a rechargeable battery, can be efficiently evaluated.