Ohmically Modulated Battery Using PTC Materials
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable batteries, particularly lithium-ion batteries, face performance issues at low temperatures and safety hazards at high temperatures, leading to inefficient power delivery and potential thermal runaway.
Innovation Solution
The development of an ohmically modulated rechargeable battery that can change its internal resistance levels significantly with temperature, featuring multiple resistance levels to optimize performance and safety by switching between low and high resistance modes based on temperature thresholds, utilizing resistor sheets and positive temperature coefficient materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery operates at low temperature, then the electrochemical kinetics and transport processes become sluggish, but the internal resistance increases leading to low power performance and low energy
Solution Approach 1:
The patent applies parameter changes by incorporating materials with positive temperature coefficient (PTC) characteristics that cause the internal resistance to increase sharply above a threshold temperature. This dynamic parameter change allows the battery to automatically adjust its electrical properties based on temperature, resolving the contradiction between maintaining performance at low temperatures and preventing thermal runaway at high temperatures.
Solution Approach 2:
The patent implements dynamics by creating a battery system where the internal resistance is not static but dynamically adjusts with temperature. The PTC materials enable the resistance to transition from a low state at operating temperatures to a high state at elevated temperatures, allowing the battery to adapt its behavior to different thermal conditions and resolve the performance-safety contradiction.
2Power
If the battery operates at high temperature, then the power performance improves, but the tendency to undergo thermal runaway increases leading to safety hazards
Solution Approach 1:
The patent applies preliminary anti-action by incorporating PTC materials that proactively increase resistance before thermal runaway can occur. The sharp resistance increase above the threshold temperature acts as a preventive measure, automatically limiting current flow and heat generation before the battery reaches dangerous thermal states, thus counteracting the thermal runaway tendency in advance.
Solution Approach 2:
The patent converts the harmful effect of high temperature into a beneficial safety mechanism. The PTC materials transform the thermal energy that would otherwise lead to thermal runaway into a protective response by increasing resistance and automatically limiting power output, thus converting the harmful high-temperature condition into a beneficial self-protecting feature.
3Object-affected harmful factors
If the internal resistance is increased to reduce heat generation at high temperature, then the safety improves, but the power performance and energy delivery capability deteriorate
Solution Approach 1:
The patent resolves this contradiction through dynamics by making the internal resistance temperature-dependent rather than fixed. The PTC materials enable the resistance to remain low at operating temperatures, maintaining good power performance, and automatically increase to a high state only when temperatures exceed the safety threshold, thus dynamically balancing performance and safety requirements.
Solution Approach 2:
The patent applies parameter changes by utilizing materials whose electrical resistance changes dramatically with temperature. This parameter change allows the battery to maintain low resistance (and thus high power performance) at normal operating temperatures while automatically transitioning to high resistance (and thus low heat generation) at elevated temperatures, resolving the contradiction between power delivery and heat control.
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 solution enhances battery performance at low temperatures by increasing internal heat generation and safety at high temperatures by reducing charge/discharge currents and heat generation, thereby preventing thermal runaway.
Implementation Method 1
the battery's internal ohmic resistance can increase sharply so that maximum charge/discharge current possible is kept at low levels
Implementation Method 2
the battery's internal ohmic resistance can increase sharply so that maximum charge/discharge current possible is kept at low levels, which in turn reduces the internal heat generation substantially
Data Source
AI summary
A rechargeable battery whose ohmic resistance is modulated according to temperature is disclosed.