Battery Rapid Low-Temperature Self-Heating via Short-Circuit
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Solution Overview
Problem
Existing battery heating methods for electric vehicles are limited by restricted current, leading to slow heating and safety risks, particularly at low temperatures, where impedance increases and lithium precipitation can cause short circuits and thermal runaway.
Innovation Solution
A combined-type rapid self-heating method using controllable lossless short-circuit heating and external heating, dynamically adjusting short-circuit time thresholds based on battery state and current peaks, ensuring safe and efficient temperature rise without damaging the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current is restricted to below rated current for heating, then battery safety is improved, but heating speed and temperature rise are reduced
Solution Approach 1:
The patent applies dynamics by transitioning from static current restriction to dynamic current control. The heating system dynamically adjusts current based on real-time battery temperature, heating stage, and impedance changes. During initial heating, current can exceed rated current temporarily to achieve rapid temperature rise, then transitions to controlled current as temperature approaches target, resolving the contradiction between safety and heating speed.
Solution Approach 2:
The patent changes the parameter of heating current from a fixed restricted value to a variable parameter that adapts to battery state. By monitoring impedance changes and temperature feedback, the system optimizes current magnitude at different heating stages, enabling both rapid heating and safety protection through parameter optimization rather than simple restriction.
2Productivity
If external short-circuit is triggered for rapid heating, then heating effect is improved, but battery performance and service life are damaged
Solution Approach 1:
The patent applies partial or excessive action by allowing temporary excessive current during controlled short-circuit heating phases. The system intentionally permits current to exceed normal operating limits for specific durations and under specific conditions to achieve rapid heating, while using feedback control to ensure the battery recovers and operates within safe parameters afterward, thus gaining heating effectiveness without permanent damage.
Solution Approach 2:
The patent implements feedback control by continuously monitoring battery temperature, impedance, and voltage during short-circuit heating. The system uses this feedback to determine when to initiate and terminate short-circuit events, ensuring that heating is achieved while preventing cumulative damage. The feedback mechanism allows the system to adapt to battery state and avoid conditions that would permanently harm battery performance.
3Temperature
If heating time is extended to achieve target temperature, then temperature rise is improved, but energy consumption and heating efficiency are reduced
Solution Approach 1:
The patent applies periodic action through pulsed heating cycles, particularly during short-circuit heating phases. Instead of continuous heating, the system uses periodic short-circuit events separated by intervals, allowing heat to distribute and battery impedance to reset. This periodic approach achieves target temperature more efficiently than continuous heating by leveraging thermal accumulation while minimizing energy waste during transition phases.
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 method enables rapid and effective battery heating at low temperatures, enhancing safety and service life by dynamically adjusting short-circuit duration and utilizing external heating to achieve target temperatures, thus improving battery performance across various climates and conditions.
Implementation Method 1
triggering a large-current external short-circuit for rapid heating of a battery
Data Source
AI summary
The present invention relates to a rapid low-temperature self-heating method and device for a battery. Active controllable large-current lossless short-circuit self-heating cooperates with an external heater to implement rapid composite heating, so that a battery is rapidly heated in a low-temperature environment and is controlled to fall within an optimal working temperature interval, so as to improve energy utilization of the battery and durability of a battery system. Before the battery system is started, battery temperature is first determined; when the temperature is less than a threshold, an external short-circuit is first proactively triggered to generate a large current to implement self-heating inside the battery. The method is simple, easy to implement, and safe and reliable, and can effectively resolve a problem that an electric vehicle has large capacity degradation and poor working performance in a low-temperature severe cold working condition.