Autoclavable Battery Thermal Switch for Sterilization Heat Isolation
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Solution Overview
Problem
Batteries degrade due to exposure to high temperatures during autoclave sterilization processes, which are necessary for medical devices, leading to reduced lifespan and irreversible damage.
Innovation Solution
A thermal switch mechanism is incorporated into the battery design, utilizing a thermally conductive outer shell with a higher coefficient of thermal expansion than the inner shell, causing the pin to separate from the inner shell at elevated temperatures, preventing heat transfer and protecting the electrochemical cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is sterilized using an autoclave process, then sanitary requirements are met, but the battery experiences heat exposure causing degradation and reduced lifespan
Solution Approach 1:
The battery is divided into an inner shell containing the electrochemical cell and an outer shell with different CTE. This segmentation allows the outer shell to expand and contract differently during temperature changes, enabling the thermal switch mechanism to protect the inner shell from heat while allowing sterilization of the outer shell.
Solution Approach 2:
A thermal switch pin is introduced as an intermediary component between the inner and outer shells. The pin thermally couples the shells at low temperatures to dissipate heat, but separates at high temperatures to isolate the inner shell from external heat exposure during autoclave sterilization.
2Temperature
If the outer shell is thermally conductive to dissipate internal heat, then battery temperature is controlled, but external heat can penetrate to the electrochemical cell
Solution Approach 1:
The thermal conductivity of the battery structure is made dynamic through the thermal switch pin. At low temperatures, the pin provides a thermally conductive path for heat dissipation. At high temperatures, the pin separates, making the structure thermally insulating to block external heat penetration.
Solution Approach 2:
The thermal conductivity parameter of the battery structure changes based on temperature. The thermal switch pin transitions from a conductive state at low temperatures to a non-conductive state at high temperatures, automatically adjusting the thermal properties to match operating conditions.
3Adaptability or versatility
If the outer shell material has high CTE for thermal switch operation, then thermal switching is enabled, but structural stability may be compromised
Solution Approach 1:
Different parts of the battery structure have different material properties optimized for their specific functions. The outer shell uses high CTE material for thermal switching, while the inner shell uses low CTE material for structural stability. This local differentiation allows each component to excel at its primary function without compromising the other.
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 thermal switch effectively protects the battery from external heat, maintaining its integrity and performance by transferring internal heat to the environment while preventing external heat from entering, thus preserving battery life and functionality.
Implementation Method 1
as ambient temperature increases the outer shell (i) expands to a greater degree than the inner shell
Implementation Method 2
The thermal switch may be configured to transfer internal heat generated by the battery to the external environment under general operating conditions
Implementation Method 3
to prevent transfer of heat from the external environment into the battery at elevated external temperatures
Data Source
AI summary
Systems and methods for electrochemical cells, or batteries, wherein the batteries include at least a first inner shell, a second outer shell, and a pin, wherein each of the first inner shell, second outer shell, and pin are thermally conductive. Under most operating temperatures the pin thermally couples the first shell to the second shell. The batteries include at least one thermally expansive component, which may be one of the shells that expands when the battery is exposed to elevated temperatures. As temperatures rise, the expansive component expands such that the pin no longer thermally couples the first and second shells, thereby disconnecting the path of heat flow from an external heat source to inside the electrochemical cell and thereby preventing cell damage. A spring may be included to ensure robust thermal coupling between the first and second shell during normal operating temperatures.