Thermal Matrix Preheating for Low-Temperature Battery Pack Charging
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Solution Overview
Problem
Lithium-ion battery packs face challenges with slow charging rates at low temperatures, leading to prolonged downtime and battery aging, as existing techniques lack effective methods for improving fast-charging performance at the pack level.
Innovation Solution
A method involving a thermal management composite matrix that preheats the battery pack to a predetermined minimum temperature, allowing for increased charging rates by directing a warming electric current through the matrix, which can be generated from the battery pack or an external charger, enabling dynamic and fast charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If fast charging is applied to lithium-ion battery packs at low temperatures, then charging speed is improved, but battery performance and safety deteriorate due to slow charging rates and prolonged downtime
Solution Approach 1:
The patent applies preliminary action by preheating the battery pack before fast charging begins. The thermal management system activates heating elements to raise the battery temperature to an optimal range (above 0°C, preferably above 10°C) prior to initiating high-rate charging. This preliminary temperature preparation enables subsequent fast charging to proceed effectively without the performance degradation that would occur at low temperatures, thus resolving the contradiction between charging speed and battery performance.
2Loss of time
If oversized battery packs are used to mitigate long downtime, then operational availability is improved, but weight and size increase
Solution Approach 1:
The thermal management system performs preliminary heating of the battery pack during periods when the vehicle is not in use or during idle time. By preparing the battery thermally in advance, the system enables fast charging to occur quickly when needed, thereby reducing actual downtime without requiring an oversized battery pack. This approach allows the use of appropriately sized battery packs while still achieving minimal downtime through rapid charging capability.
Solution Approach 2:
The patent changes the temperature parameter of the battery pack from low temperature (which limits charging rate) to optimal temperature range through active thermal management. By dynamically adjusting and maintaining the battery temperature within an optimal range during charging operations, the system enables sustained fast charging rates that reduce overall charging time and downtime, eliminating the need for oversized battery packs to compensate for slow charging.
3Productivity
If fast charging is performed at low temperatures, then charging rate is improved, but battery aging increases and cycle life decreases
Solution Approach 1:
The system performs preliminary heating to raise the battery temperature to an optimal range before initiating fast charging. This temperature preparation ensures that the electrochemical reactions proceed efficiently at high rates without the adverse effects of low temperature, thereby enabling fast charging to be performed rapidly without accelerating battery aging or reducing cycle life.
Solution Approach 2:
The thermal management system continuously monitors battery temperature and charging rate, using feedback control to maintain optimal operating conditions. During fast charging, the system adjusts heating or cooling actions based on real-time temperature measurements to keep the battery within the optimal temperature range, preventing temperature-related degradation while sustaining high charging rates throughout the charging process.
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 approach enhances charging speed and cycle life by optimizing temperature and voltage control, allowing for faster charging without compromising safety or longevity, particularly at low temperatures.
Implementation Method 1
heating the battery pack by directing a warming electric current through the thermal management composite matrix
Implementation Method 2
a phase change composite (PCC)
Data Source
AI summary
A method and apparatus for charging a battery pack including a plurality of electrochemical cells distributed within a thermal management composite matrix, including a phase change material. The method operates upon determining that a battery pack temperature and/or voltage measurement is below a predetermined minimum threshold. The pack temperature and/or the voltage measurement is raised to the predetermined minimum threshold, such as by applying a low current rate, and then the charging rate is increased upon reaching the predetermined minimum threshold. The increased charging rate is further selected based upon a thermal state of charge of the thermal management composite matrix.