Hybrid Powertrain Control for Low-Temperature Battery Output Limits
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Solution Overview
Problem
Hybrid vehicles experience reduced battery discharge characteristics and deteriorated driving performance during cold starts due to low battery temperatures, leading to limited electric motor output.
Innovation Solution
A controller manages the power source in hybrid vehicles to switch between EV and HEV modes based on battery temperature, using the electric motor to charge or discharge the battery and engage the engine to generate power, while an electric vehicle employs a heater and temperature sensor to actively warm the battery, enhancing discharge characteristics and motor output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the hybrid vehicle is started under a low-temperature environment, then the battery temperature is low, but the discharge characteristic of the battery is low
Solution Approach 1:
The system performs preliminary heating of the battery before normal operation using the heater element. The control unit activates the heater when battery temperature falls below the threshold, warming the battery in advance to ensure optimal discharge characteristics are achieved before the battery is fully utilized for power delivery.
Solution Approach 2:
The control unit acts as an intermediary between the battery and the heater, monitoring battery temperature and deciding when to activate the heating function. This intermediary control mechanism ensures the battery is warmed at the appropriate times without requiring direct manual intervention or complex thermal management systems.
2Power
If the battery temperature is low, then the discharge characteristic is low, but the output of the electric motor is limited
Solution Approach 1:
The control unit continuously monitors battery temperature and adjusts the heater activation accordingly. When the battery temperature is below the threshold, the control unit activates the heater; when the temperature rises above the threshold, the control unit deactivates the heater. This feedback mechanism ensures the battery maintains optimal temperature for maximum electric motor output without unnecessary energy consumption.
3Temperature
If a heater is used to heat the battery, then the battery temperature is increased, but energy is consumed from the battery
Solution Approach 1:
The system applies partial heating action by activating the heater only when the battery temperature falls below the predetermined threshold. The heater is not continuously operated but rather provides just enough heating to bring the battery temperature to the acceptable range, avoiding excessive energy consumption while still achieving the desired temperature increase for optimal battery performance.
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 quickly recovers battery temperature and discharge characteristics, maintaining driving performance and preventing deterioration, even at cold starts, by strategically managing power distribution and heating the battery.
Implementation Method 1
a heater that generates heat by the electric power from the battery to heat the battery
Implementation Method 2
the controller controls the driving power source so as to operate the electric motor in a state where electric current flows between the battery and the electric motor
Data Source
AI summary
A hybrid vehicle includes: a driving power source including an engine and an electric motor; a battery that supplies electric power to the electric motor; and a controller that controls the engine and the electric motor according to a temperature of the battery. When a predetermined EV mode condition is satisfied, and a normal-temperature condition in which the temperature of the battery is a threshold or more is satisfied, the controller controls the driving power source in an EV mode in which the electric motor is driven. When the EV mode condition is satisfied, and a low-temperature condition in which the temperature of the battery is less than the threshold is satisfied, the controller operates the electric motor in a state where electric current flows between the battery and the electric motor drives the engine such that the engine generates traveling power transmitted to a driving wheel.