Hybrid Vehicle Running Mode Control for Battery Degradation
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Solution Overview
Problem
Hybrid vehicles with external rechargeability face inefficiencies in energy utilization and battery degradation when the target charge level is set too high, leading to unnecessary engine startups and reduced regenerative energy absorption.
Innovation Solution
A hybrid vehicle system that includes a chargeable power storage device, an internal combustion engine, a power generation device, an electric motor, and a running mode control unit, allowing the vehicle to switch between EV priority mode and HV mode based on the state of charge (SOC) to optimize energy use and prevent battery degradation, with user-settable SOC targets and automatic mode changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the target amount of charge α is set at a great value to ensure charging energy for regeneration, then regenerative energy recovery is improved, but the engine starts unnecessarily without sufficiently utilizing charged electric power, reducing energy utilization efficiency
Solution Approach 1:
The patent applies dynamics by making the target charge amount α variable rather than fixed. The control device dynamically adjusts α based on real-time vehicle conditions including battery temperature, charge/discharge rates, and external temperature. This allows the system to optimize the balance between regenerative energy recovery and energy utilization efficiency under different operating conditions, preventing unnecessary engine startups while ensuring sufficient charging capacity when needed.
2Quantity of substance
If the target amount of charge α is set at a great value to maintain large battery charge, then charging capacity is improved, but battery degradation occurs due to constant large charge state
Solution Approach 1:
The system dynamically adjusts the target charge amount α based on battery temperature and other conditions. When battery temperature is high, the target charge amount is reduced to prevent excessive charge states that cause degradation. When temperature is low, the target charge amount can be higher. This dynamic adjustment maintains sufficient charging capacity while protecting battery lifespan through condition-based optimization.
Solution Approach 2:
The patent changes the parameter of target charge amount α based on battery temperature and charge/discharge rates. By adjusting this key parameter according to thermal conditions, the system prevents the battery from remaining in a constant large charge state that causes degradation, while still maintaining adequate charging capacity for regenerative energy recovery.
3Use of energy by stationary object
If the target amount of charge α is set at a great value for external power charging, then charging from external source is improved, but the state where amount of charge is constantly large continues, causing battery degradation
Solution Approach 1:
During external power charging, the system dynamically determines the target charge amount α based on battery temperature and other conditions rather than setting it to a maximum fixed value. This allows the battery to be charged from external sources effectively while preventing the charge state from remaining constantly large, thereby avoiding degradation and extending battery lifespan.
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 solution enables effective utilization of external power, prevents battery degradation, and improves user convenience by allowing discretionary SOC settings and automatic mode changes, ensuring efficient energy use and reduced engine usage.
Implementation Method 1
a power generation device capable of generating electric power using kinetic energy produced by the internal combustion engine to charge the power storage device
Implementation Method 2
a charging device capable of receiving a supply of electric power from a power source outside the vehicle to charge the power storage device
Implementation Method 3
an electric motor capable of receiving a supply of electric power from the power storage device to produce driving force for the vehicle
Data Source
AI summary
An EV priority switch is configured to allow a user to request a change between an EV priority mode and an HV mode. If an SOC of a power storage device is less than a first threshold value when the change to the HV mode is requested from the EV priority switch during the EV priority mode, an ECU changes the running mode to attain the HV mode and controls the SOC to be close to the SOC at the moment of a request for the change to the HV mode. If the SOC is greater than or equal to the first threshold value, the ECU maintains the EV priority mode. If the SOC reaches a second threshold value less than the first threshold value, the ECU forcefully changes the running mode to attain the HV mode.