External IMD Charger Thermal Diffuser for Fast Charging Heat Control
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Solution Overview
Problem
The existing external chargers for implantable medical devices face challenges with thermal management, leading to overheating and reduced power delivery due to Eddy currents generated by the magnetic field, and the placement of temperature sensors is prone to damage and inaccurate temperature sensing.
Innovation Solution
The improved charging system separates the electronics module and charging coil assembly with a thermal diffuser and multiple temperature sensors, allowing for better heat dissipation and accurate temperature monitoring, reducing overheating and enhancing power delivery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the external charger generates a strong magnetic field for fast charging, then power delivery efficiency is improved, but thermal management becomes problematic due to Eddy currents and overheating
Solution Approach 1:
A thermal diffuser is introduced as an intermediary component between the charging coil assembly and the housing. This thermal diffuser includes a first portion in contact with the charging coil assembly and a second portion in contact with the housing, creating a thermal management pathway that allows heat to be dissipated through the housing to the patient's body, thereby preventing overheating while maintaining fast charging capability
Solution Approach 2:
The patent converts the harmful Eddy currents and generated heat into a beneficial thermal management system. By intentionally designing a thermal pathway through the housing to the patient's body (which acts as a heat sink), the previously harmful thermal effects are harnessed to maintain safe operating temperatures during fast charging
2Measurement precision
If temperature sensors are placed close to the charging coil for accurate temperature sensing, then measurement precision is improved, but reliability decreases due to damage from Eddy currents and magnetic field exposure
Solution Approach 1:
The temperature sensing function is segmented and distributed to multiple sensors placed at different locations within the housing. This includes sensors positioned to monitor temperatures near the charging coil, at the housing exterior, and at other critical thermal zones, allowing comprehensive temperature monitoring without exposing any single sensor to damaging conditions
Solution Approach 2:
The patent transitions from a single-point temperature measurement to a distributed spatial temperature monitoring system. By placing multiple sensors at different three-dimensional locations within the charger housing, the system captures the thermal field distribution, enabling accurate temperature sensing without requiring any single sensor to be positioned in the most hazardous zone
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 design enables higher power magnetic field generation without overheating, allowing for faster and more efficient charging of implantable medical devices while ensuring reliable and accurate temperature sensing.
Implementation Method 1
The charging coil assembly includes a charging coil that generates a magnetic field for charging or recharging the IMD's battery
Implementation Method 2
a charging coil assembly including a charging coil and a thermal diffuser
Data Source
AI summary
An external charging system for an Implantable Medical Device (IMD) is disclosed having a thermal diffuser proximate to the primary charging coil for distributing heat from the primary charging coil. In an example, the primary charging coil is mounted to a first side of a circuit board, and the thermal diffuser is also connected to the first side and in contact with the primary charging coil. In one example, the thermal diffuser is a plastic material, such as an acrylic pad, with a high thermal conductivity and a low electrical conductivity. The thermal diffuser may also contact temperature sensors mounted to the first side of the circuit board.