EV Battery Preconditioning Using Heat and Cold Buffering
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Solution Overview
Problem
Existing air-conditioning systems in electrified vehicles face conflicts between cooling requirements of the high-voltage accumulator and the interior, leading to potential degradation of the accumulator due to excessive heating and reduced comfort, with inefficient energy consumption during temperature regulation.
Innovation Solution
A method and device that utilize a preconditioning mode (VOKO+) to predict outside temperature and route length, using the high-voltage accumulator as a heat accumulator to optimize temperature settings, reducing energy consumption and maintaining optimal temperatures during the journey.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air-conditioning installation is used to cool the high-voltage accumulator, then the accumulator temperature is reduced, but the cooling potential is insufficient to meet both the accumulator and interior cooling requirements simultaneously
Solution Approach 1:
The system performs preliminary cooling of the high-voltage accumulator during charging phases when the interior cooling demand is low. By proactively reducing the accumulator temperature before the driving phase begins, the system creates a thermal buffer that delays the need for active cooling during high-demand periods, ensuring sufficient cooling potential remains available for interior comfort.
Solution Approach 2:
The air-conditioning installation dynamically adjusts its operation between two modes: accumulator cooling mode during charging when interior temperature is acceptable, and interior cooling mode during driving when accumulator temperature is acceptable. This dynamic switching optimizes the distribution of limited cooling potential based on real-time thermal requirements.
2Reliability
If the high-voltage accumulator is cooled during operation, then thermal loading is reduced, but energy consumption increases and range is reduced
Solution Approach 1:
The system performs preliminary cooling of the high-voltage accumulator during charging phases when the vehicle is stationary. By proactively reducing the accumulator temperature before the driving phase begins, the system creates a thermal buffer that delays the need for active cooling during high-demand periods, ensuring sufficient cooling potential remains available for interior comfort.
Solution Approach 2:
The system utilizes the otherwise wasted thermal energy from the high-voltage accumulator during charging to pre-cool the accumulator. This converts what would be harmful heat generation into a beneficial preconditioning action, reducing the need for active cooling during subsequent driving phases and thereby reducing overall energy consumption.
3Loss of time
If the high-voltage accumulator is supercooled below operating temperature, then a cold buffer is created that delays cooling requirements, but the air-conditioning installation is used when not strictly necessary
Solution Approach 1:
The system performs preliminary cooling of the high-voltage accumulator during charging phases when the interior cooling demand is low. By proactively reducing the accumulator temperature before the driving phase begins, the system creates a thermal buffer that delays the need for active cooling during high-demand periods, ensuring sufficient cooling potential remains available for interior comfort.
Solution Approach 2:
The system changes the operational parameters of the air-conditioning installation by adjusting the target temperature setpoint for the high-voltage accumulator. During preconditioning phases, the system allows the accumulator to be cooled below the standard operating temperature range, creating a larger thermal buffer that extends the time before active cooling is required during driving.
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
Reduces energy consumption and extends the vehicle's range by utilizing the high-voltage accumulator as a heat buffer, minimizing degradation and ensuring comfortable interior conditions.
Implementation Method 1
the air-conditioning installation having a specific cooling potential which can be used to cool the interior and the high-voltage accumulator
Implementation Method 2
thermal energy, in particular waste heat, from the energy accumulator is taken up and passed to the device for air-conditioning the passenger compartment
Implementation Method 3
a cold buffer is then advantageously created, this delaying the time of any possible cooling requirement at the high-voltage accumulator
Data Source
AI summary
An air-conditioning system for an electrified motor vehicle with an interior and a high-voltage accumulator, includes an air-conditioning installation and an electronic control unit. The air-conditioning installation air-conditions both the interior and the high-voltage accumulator. The control unit implements a preconditioning mode during charging of the parked vehicle before a journey begins in such a way that: (a) at least the length of the route and the outside temperature over the length of the route can be predicted, and (b) in that, depending on the prediction, the high-voltage accumulator can be used as: (i) a heat accumulator, when the predicted outside temperature over the length of the route is lower than the heating threshold target temperature required by the high-voltage accumulator, or (ii) a cold accumulator, when the predicted outside temperature over the length of the route is greater than the heating threshold target temperature required by the high-voltage accumulator.