Hybrid EV Battery Control for Speed-Based Charge and Discharge
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Solution Overview
Problem
Existing hybrid battery systems in electric vehicles face challenges in efficiently managing the discharge and charge cycles of high energy and high power batteries, leading to uneven wear and reduced lifespan, particularly due to the lack of effective control strategies that optimize the use of both battery types based on vehicle speed and current requirements.
Innovation Solution
A method is proposed where high energy batteries are used for discharging at higher speeds and lower currents, while high power batteries are utilized for higher currents, and both types are used together for high power demands, with specific charging strategies that prioritize the high power battery when fully charged and the high energy battery when necessary, utilizing a control unit to execute these strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If high energy batteries are used exclusively for discharging, then the battery system can supply high current for extended periods, but the high power battery cannot maintain readiness for high current demands and overall system reliability decreases
Solution Approach 1:
The battery system is segmented into two distinct functional units: high energy batteries for sustained discharge and high power batteries for high current bursts. This segmentation allows each battery type to operate within its optimal performance range, with the control unit dynamically assigning tasks based on real-time power demands.
Solution Approach 2:
The control unit dynamically adjusts the operational state of each battery type based on real-time vehicle speed and current requirements. At lower speeds with high current demands, high power batteries are activated; at higher speeds with lower current demands, high energy batteries are used exclusively. This dynamic allocation optimizes both discharge duration and system reliability.
2Power
If high power batteries are used for all discharging, then high current demands are met, but aging effects increase significantly and lifespan is reduced
Solution Approach 1:
The system changes operational parameters by switching between different battery configurations based on vehicle speed thresholds. When vehicle speed exceeds the first threshold value, high energy batteries are used exclusively. When speed is below the threshold, high power batteries are activated. This parameter-based switching reduces unnecessary cycling of high power batteries, minimizing aging effects and extending lifespan while maintaining required power output.
3Adaptability or versatility
If both battery types are used together for all conditions, then power and energy requirements are always met, but control complexity increases and optimization is reduced
Solution Approach 1:
Different battery configurations are applied to different operational conditions: high energy batteries for high-speed/low-current conditions, high power batteries for low-speed/high-current conditions, and both together for high-speed/high-current conditions. This localized quality approach ensures each battery type operates in its optimal range for specific conditions, achieving operational adaptability without excessive control complexity.
4Reliability
If charging current is always directed to high power battery, then high power battery remains ready for high current, but high energy battery aging increases and overall system efficiency decreases
Solution Approach 1:
The control unit continuously monitors the state of charge of both battery types and dynamically directs charging current based on real-time conditions. When high energy battery charge level exceeds the second threshold, charging current is directed to the high power battery. When it is below the threshold, charging current charges the high energy battery. This feedback-based control ensures high power battery readiness while preventing unnecessary cycling of the high energy battery, extending its lifespan and improving overall system efficiency.
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 reduces the aging effects on both battery types, keeps the high power battery ready for high discharging currents, and extends the overall battery system's lifespan by optimizing energy usage and minimizing unnecessary charging and discharging.
Implementation Method 1
Batteries convert chemical energy into electrical energy. Particularly, rechargeable batteries are known to be able to be charged and discharged several times.
Implementation Method 2
the battery system is designed to supply a discharging current to an electric motor for driving the electric vehicle
Implementation Method 3
the battery system is designed to be charged by a charging current caused by recuperation from an electric motor of the electric vehicle
Data Source
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AI summary
The invention refers to a method for discharging a hybrid battery system (10) in an electric vehicle, the battery system (10) being designed to supply a discharging current to an electric motor (25) for driving the electric vehicle and the battery system (10) comprising at least one high energy battery (12) and at least one high power battery (14), whereat the at least one high energy battery (12) is used to supply a discharging current to the electric motor (25) when a speed of the electric vehicle is higher than a determined first speed value, and whereat the at least one high power battery (14) is used to supply a discharging current to the electric motor (25) when the speed of the electric vehicle is lower than the determined first speed value. The invention also refers to a method for charging a hybrid battery system (10) in an electric vehicle, the battery system (10) being designed to be charged by a charging current caused by recuperation from an electric motor (25) of the electric vehicle and the battery system (10) comprising at least one high energy battery (12) and at least one high power battery (14), whereat the at least one high power battery (14) is charged by a charging current unless a state of charge of the high power battery (14) is higher than a determined first level. The invention also refers to a battery system (10) for an electric vehicle, comprising at least one high energy battery (12), at least one high power battery (14) and a control unit (20) for controlling and supervising the at least one high energy battery (12) and at least one high power battery (14), whereat the control unit (20) is designed to execute a method according to the invention.