Battery Circuit Diode Heating for Low-Temperature Li-Ion Reactivity
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Solution Overview
Problem
Lithium-ion batteries used in vehicles experience reduced reactivity at low temperatures, leading to performance issues and potential functional restrictions.
Innovation Solution
An electrical circuit device and method that utilizes semiconductor components with integrated switches and diodes to direct charging and discharge currents through diodes, generating Joule heat to warm the battery, and incorporates a heat transfer medium to optimize heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If separate heating elements are installed in the battery to increase temperature at low temperatures, then the battery reactivity is improved, but the device complexity and weight increase
Solution Approach 1:
The battery system uses its own charging/discharging current to generate heat through the diodes, eliminating the need for external heating elements. The current that would otherwise be blocked by the diodes is redirected to flow through them, converting electrical energy into thermal energy that heats the battery from within.
Solution Approach 2:
The diodes, which normally block current flow and represent a limitation or 'harm' to charging/discharging operations, are instead utilized to generate heat. By allowing current to flow through the diodes during cold conditions, the previously wasted energy becomes a beneficial heating source that improves battery performance.
2Temperature
If the diode blocking function is used to generate heat, then heating efficiency is improved, but energy loss during normal charging/discharging increases
Solution Approach 1:
The system dynamically adjusts the operation of semiconductor switches based on temperature conditions. During cold conditions, the switches are configured to direct current through the diodes for heating. During normal operation at acceptable temperatures, the switches redirect current away from the diodes to prevent energy loss, allowing bidirectional current flow without heating.
Solution Approach 2:
The system changes the operational parameters of the semiconductor switches based on temperature feedback. When the battery temperature drops below a threshold, the switch states are modified to enable current flow through the diodes. When temperature is adequate, the switch states return to normal blocking operation, eliminating energy loss while maintaining the heating capability when needed.
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 method effectively generates heat within the battery using current flows, enhancing the reactivity of lithium-ion batteries at low temperatures without the need for separate heating elements, thereby improving vehicle performance.
Implementation Method 1
generate Joule heat by way of current flow in the forward direction of the first diode
Implementation Method 2
transfer Joule heat from the first diode and/or second diode to the electrical energy storage unit
Data Source
AI summary
A method for operating an electrical circuit device includes the method step of opening a first switch and closing a second switch in order, in the case of a charging current or in the case of a discharging current of an electrical secondary storage unit, to generate Joule heat by way of current flow in the forward direction of a first diode, and/or including the method step of closing the first switch and opening the second switch in order to generate Joule heat in the case of current flow of the respective other current in the forward direction of a second diode.