Battery Housing Two-Phase Cooling for High-Density Battery Stacks
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Solution Overview
Problem
Existing cooling solutions for battery packs in data centers, such as air and liquid cooling, fail to support high power density and high packaging densities, and there is a lack of two-phase coolant designs for battery cells.
Innovation Solution
A two-phase fluid recirculation and management system for thermal management using two-phase coolants, with a battery pack design that includes dedicated fluid channels and condensers for each cell, allowing vapor management and leakage containment, integrated into an IT enclosure for efficient thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If air cooling or liquid cooling is used for battery packs, then cooling function is provided, but high power density and high packaging density cannot be achieved
Solution Approach 1:
The patent employs two-phase immersion cooling where a dielectric fluid undergoes phase transition from liquid to vapor and back, absorbing and releasing latent heat to cool battery cells. The coolant circulates through channels, evaporates at hot spots, condenses in cooler regions, and returns to repeat the cycle, enabling high power density thermal management that air or single-phase liquid cooling cannot achieve
Solution Approach 2:
The system uses a closed-loop hydraulic circuit with pumps, valves, and heat exchangers to circulate the dielectric fluid through the battery pack. The hydraulic system maintains controlled flow rates and pressures to optimize heat transfer efficiency while enabling high packaging density through compact component integration
2Power
If battery discharge rate is increased to meet higher energy consumption, then power delivery is improved, but heat generation increases requiring more cooling
Solution Approach 1:
The two-phase cooling system leverages the high latent heat of vaporization of the dielectric fluid to efficiently remove heat generated during high-rate battery discharge. As the fluid evaporates in direct contact with hot battery surfaces, it absorbs large amounts of heat energy, enabling the system to handle high power delivery scenarios without temperature runaway
Solution Approach 2:
The closed-loop cooling system maintains continuous circulation of the dielectric fluid through evaporation and condensation cycles. The pump continuously replenishes evaporated fluid to the heat source, ensuring uninterrupted heat removal during sustained high-power operation, preventing thermal accumulation that would limit power delivery capability
3Productivity
If faster battery charging is implemented to reduce refueling time, then charging speed is improved, but heat generation increases requiring enhanced cooling
Solution Approach 1:
During fast charging, the two-phase system uses rapid evaporation of the dielectric fluid at battery cell surfaces to absorb the intense heat generated by high charging currents. The phase change process provides superior heat flux removal capability compared to single-phase cooling, enabling faster charging rates without exceeding thermal limits
Solution Approach 2:
The system pre-cools the dielectric fluid in the condenser and heat exchangers before it reaches the battery cells, maximizing its heat absorption capacity. This preliminary cooling preparation ensures the fluid is at optimal temperature to immediately absorb heat during fast charging events, maintaining productivity while controlling temperature
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
Enables high power density thermal management, efficient vapor management, and prevents cell degradation while accommodating different server and IT systems, facilitating ease of implementation and maintenance.
Implementation Method 1
two-phase fluid recirculation and management system for thermal management using two-phase coolants
Implementation Method 2
A condenser is positioned at the top of the battery housing and fluidly coupled to the N fluid channels, so that vapor from each battery pack flows through each battery pack's corresponding fluid channel to the condenser
Implementation Method 3
two-phase coolants, with a battery pack design that includes dedicated fluid channels and condensers for each cell
Data Source
AI summary
Embodiments are disclosed of an energy storage unit. The unit includes a battery housing and a battery stack positioned in the battery housing. The battery stack includes N vertically stacked battery packs, N≥2, and the N battery packs include at least a bottom battery pack and a top battery pack. N fluid channels formed in the battery housing, with each fluid channel fluidly coupled to a corresponding battery pack and extending vertically from its corresponding battery pack to the top of the battery housing. A condenser is positioned at the top of the battery housing and is fluidly coupled to the N fluid channels, so that vapor from each battery pack flows through the battery pack's corresponding fluid channel to the condenser and liquid condensed by the condenser return to the channels of corresponding battery pack.