Hybrid Vehicle Battery Range Shifting for Ageing Reduction
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Solution Overview
Problem
High voltage lithium ion energy storage devices in hybrid vehicles age faster at high temperatures and high states of charge, leading to reduced performance and the need for larger, less efficient designs to ensure cold starts and adequate storage capacity.
Innovation Solution
Shifting the operating range of the high voltage energy storage device based on vehicle and environmental parameters, such as temperature and operating mode, to reduce ageing and maintain performance, while ensuring reliable engine starts at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high voltage energy storage device is operated within a fixed working range to ensure cold start capability and adequate storage capacity, then the vehicle can reliably start the internal combustion engine and perform brake energy regeneration, but the energy storage device ages faster at high temperatures and high states of charge, reducing its service life
Solution Approach 1:
The patent applies dynamics by making the working range of the energy storage device adjustable rather than fixed. The control unit dynamically shifts the working range based on temperature conditions: at low temperatures, the working range is shifted to higher states of charge to ensure cold start capability, while at high temperatures, it is shifted to lower states of charge to reduce ageing. This dynamic adaptation resolves the contradiction between maintaining reliable cold starts and extending service life.
Solution Approach 2:
The patent changes the operating parameters (state of charge limits) of the energy storage device based on temperature conditions. By adjusting the upper and lower limits of the working range as a function of temperature, the system optimizes both cold start reliability and service life. At low temperatures, the state of charge is maintained higher, while at high temperatures, it is kept lower, thus resolving the contradiction through parameter adaptation.
2Quantity of substance
If the working range of the energy storage device is fixed to maintain adequate storage capacity for brake energy regeneration, then the vehicle can effectively recover braking energy, but the energy storage device undergoes slower ageing only at lower states of charge, which conflicts with the need for adequate storage capacity
Solution Approach 1:
The patent makes the working range dynamic by shifting it based on temperature conditions. During braking events, the control unit can temporarily adjust the working range to accommodate energy regeneration needs while considering the current temperature. This allows the system to balance storage capacity requirements with ageing reduction by adaptively managing the state of charge limits.
3Quantity of substance
If the high voltage energy storage device is designed with larger capacity to ensure adequate storage for brake energy regeneration and cold starts, then the vehicle can meet all operational requirements, but the size and weight of the energy storage device increase
Solution Approach 1:
The patent changes the operating parameters (working range limits) of the energy storage device to optimize its utilization. By shifting the working range based on temperature, the system maximizes the effective capacity of a given battery size. At low temperatures, the working range is shifted to ensure cold start capability, while at high temperatures, it is shifted to reduce ageing, thereby extracting maximum performance from a smaller, lighter battery pack.
Data Source
AI summary
A method for operating an electric high voltage energy storage device of a hybrid vehicle with an electric drive motor, as well as an energy supply device, is provided. A predetermined working range of the high voltage energy storage device is shifted in the direction of the upper or lower physical charge limit as a function of the vehicle operating parameters and/or as a function of the vehicle environmental parameters.