Parallel Coupling Store Device for Motor Vehicle Energy Management
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Solution Overview
Problem
Conventional motor vehicles with single energy storage systems, such as lead-acid batteries, face reduced lifespan due to frequent partial discharge and stop phases, especially with micro-hybrid functionalities like brake energy recovery and automatic engine start-stop functions, which negatively impact the battery's state of charge and overall electrical system efficiency.
Innovation Solution
A motor vehicle with two electrical energy storage devices connected in parallel, where the first energy store has a higher charging internal resistance and lower discharging internal resistance characteristic, and the second energy store has a lower charging internal resistance and higher discharging internal resistance characteristic, operated in a voltage-neutral manner without intermediate voltage-coupling components, allowing for efficient energy management and extended lifespan through targeted state of charge control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lead-acid battery is used for basic vehicle electrical systems, then the system structure is simple, but the battery lifespan is reduced due to frequent partial discharge and stop phases
Solution Approach 1:
The patent divides the single battery system into two separate energy storage devices: a first energy storage device (lead-acid battery) and a second energy storage device (lithium-ion battery or supercapacitor). This segmentation allows each battery type to operate in its optimal state of charge range, with the second device handling frequent charge/discharge cycles during stop phases and brake energy recovery, thereby extending the lifespan of the first battery while maintaining system functionality.
2Use of energy by moving object
If brake energy recovery and automatic engine start-stop functions are implemented, then energy efficiency is improved, but the battery undergoes frequent partial discharge which reduces its lifespan
Solution Approach 1:
The patent introduces a second energy storage device as an intermediary between the generator and the first battery. This intermediary absorbs the frequent charge/discharge cycles from brake energy recovery and engine start-stop functions, protecting the first battery from excessive partial discharge while enabling the micro-hybrid functionalities to operate efficiently.
3Productivity
If two energy storage devices with different internal resistance characteristics are connected in parallel, then energy management efficiency is improved, but the system complexity increases
Solution Approach 1:
The patent assigns different functional characteristics to each energy storage device based on their local quality: the first device (lead-acid) has lower discharging internal resistance for high current delivery during starting, while the second device (lithium-ion or supercapacitor) has lower charging internal resistance for rapid energy absorption during brake recovery. This differentiation optimizes energy management efficiency while the control unit coordinates their operation to manage system complexity.
4Reliability
If voltage-coupling components are used between two energy storage devices, then voltage matching is ensured, but the system complexity and energy loss increase
Solution Approach 1:
The patent extracts and eliminates intermediate voltage-coupling components (such as DC-DC converters or relays) from the system. Instead, it directly connects the two energy storage devices in parallel, relying on their naturally overlapping voltage characteristics to ensure voltage compatibility. This reduces system complexity and minimizes energy losses while maintaining reliable operation.
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 configuration enhances the lifespan of the lead-acid battery by optimizing energy storage and retrieval, reducing the impact of frequent discharges and charges, and maintaining efficient energy conversion and storage, particularly in vehicles with brake energy recovery and automatic engine start-stop functions.
Implementation Method 1
a first electrical energy storage device and with a second electrical energy storage device connected in parallel with the first electrical energy storage device
Implementation Method 2
the first energy store has a first charge state-dependent internal charging resistance characteristic, the second energy store has a second state of charge dependent charging internal resistance characteristic
Data Source
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AI summary
The invention relates to a motor vehicle comprising a generator, electrical loads, a first electrical energy store and a second electrical energy store connected in parallel to the first electrical energy store, wherein the two electrical energy stores have at least partially overlapping open-circuit voltage characteristic curves in the voltage range, wherein the first energy store has a first charging state-dependent internal resistance characteristic curve of charge and the second energy store has a second charging state-dependent internal resistance characteristic curve, the first energy store has a first charging state-dependent internal resistance characteristic curve of discharge and the second energy store has a second charging state-dependent internal resistance characteristic curve of discharge, such that the first internal resistance characteristic curve of charge extends over an entire relative charging state range in the direction of higher resistances above the second internal resistance characteristic curve of charge, the first internal resistance characteristic curve of discharge extends over an entire relative charging state range in the direction of higher resistances below the second internal resistance characteristic curve of discharge, and the two energy stores are interconnected in a neutral voltage range.