Dielectric Liquid Pressure Control for Immersed Battery Cooling
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Solution Overview
Problem
Existing cooling systems for electric vehicle batteries fail to manage pressure and temperature effectively, leading to suboptimal performance, service life, and safety, particularly during charging and discharging cycles.
Innovation Solution
A method for regulating pressure in a dielectric liquid cooling system using a pressurizing means with an electrically controlled piston, detecting member, and a heat exchanger to maintain optimal pressure thresholds during charging and discharging phases, reducing the need for bulky and expensive pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pump is used to constantly generate high pressure in the cooling circuit, then the battery cells can be kept under compression to improve service life and performance, but the pump becomes heavy, bulky and expensive
Solution Approach 1:
The pressurizing means is activated before the charging step to pre-compress the battery cells. This preliminary action ensures cells are under optimal compression during charging, improving service life without requiring continuous high-pressure operation of a heavy pump throughout all battery operations
Solution Approach 2:
The system dynamically adjusts pressure based on operational phase: high pressure is applied only when needed (before and during charging/discharging), while allowing pressure to decrease during idle periods. This dynamic pressure regulation maintains cell compression benefits without requiring a constantly operating heavy-duty pump
2Reliability
If a pump is used to constantly generate high pressure in the cooling circuit, then the battery cells can be kept under compression to improve performance, but the pump becomes bulky and expensive
Solution Approach 1:
The system performs preliminary pressurization before charging operations, preparing the battery cells for optimal performance conditions. This approach maintains cell performance without requiring a complex continuously-operating high-pressure pump system
Solution Approach 2:
The pressurizing means operates periodically rather than continuously, activating only during specific phases (before and during charging/discharging). This periodic operation reduces system complexity and cost while maintaining battery performance benefits
3Device complexity
If the cooling system operates at atmospheric pressure with an expansion vessel, then the system is simpler, but the pump must constantly generate very high pressure to overcome hydraulic head losses
Solution Approach 1:
The invention extracts and removes the expansion vessel from the cooling circuit, replacing it with a closed circuit entirely filled with dielectric liquid. This elimination of the expansion vessel simplifies the system while allowing pressure to be maintained through direct control of the pressurizing means without requiring constant high-power pump operation to overcome hydraulic losses
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
Enhances battery performance, extends service life, and improves safety by maintaining consistent pressure conditions, reducing pump size and energy consumption, and optimizing charging and discharging cycles.
Implementation Method 1
a pressurizing means (12) for pressurizing the dielectric liquid within the circuit
Implementation Method 2
a detecting member (14) for detecting the pressure of the dielectric liquid within the circuit
Implementation Method 3
the cooling system comprises a heat exchanger configured to discharge the heat energy present in the dielectric liquid to an external environment
Data Source
AI summary
A method is for regulating a pressure of a dielectric liquid circulating within a cooling system of at least one battery cell of an at least in part electrically propelled vehicle. The cooling system includes a circuit in which the dielectric liquid circulates. The battery cell is immersed in the dielectric liquid. The cooling system includes structure for pressurizing the dielectric liquid within the circuit.