Immersion Cooling for Battery Backup Thermal Uniformity
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Solution Overview
Problem
Conventional thermal management systems for battery packs in data centers are insufficient in maintaining uniform temperature across battery cells, leading to differential charging and discharging rates and potential battery pack performance deterioration.
Innovation Solution
A battery backup unit (BBU) immersion cooling system that uses a coolant tank with a pump and optional fan for temperature control, where a microcontroller regulates the cooling fluid flow and fan speed based on temperature and current sensors, enabling differential thermal management for charging and discharging states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional thermal management systems are used for battery packs, then the system structure is simple, but the temperature uniformity across battery cells deteriorates
Solution Approach 1:
The battery pack is divided into multiple thermal zones with independent temperature sensors and cooling channels for each cell or group of cells. This segmentation allows differential cooling control where each cell can be cooled according to its specific temperature, achieving uniform temperature distribution across the battery pack while managing the complexity through modular design
Solution Approach 2:
Different cooling strategies are applied to different cells based on their local temperature conditions. Cells with higher temperatures receive more cooling flow or lower temperature coolant, while cooler cells receive less cooling. This local quality approach ensures each cell operates within optimal temperature ranges, improving overall temperature uniformity without requiring complete system redesign
2Productivity
If battery cells operate at different temperatures, then temperature control is easier, but charging and discharging rates become inconsistent causing performance deterioration
Solution Approach 1:
Temperature sensors on each cell provide real-time feedback to a control system that adjusts cooling flow distribution dynamically. When temperature differences between cells are detected, the system modifies coolant flow rates to each cell individually, ensuring all cells maintain similar temperatures during charging and discharging operations, thereby maintaining consistent performance
Solution Approach 2:
The cooling system transitions from static to dynamic operation, where coolant flow rates and temperatures are continuously adjusted based on real-time cell temperature measurements and operating conditions (charging/discharging rates). This dynamic adaptation ensures temperature uniformity is maintained across varying operational states, preventing performance deterioration
3Power
If higher discharge speed is used, then power output increases, but heat generation increases negatively impacting battery health
Solution Approach 1:
A liquid cooling system with coolant circulating through channels in contact with each battery cell acts as an intermediary heat transfer medium. The coolant absorbs excess heat generated during high-power discharge operations and transports it to external heat exchangers, effectively decoupling the heat generation from the battery cells and allowing sustained high power output without thermal damage to battery health
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
The BBU immersion cooling system effectively manages battery cell temperatures, enhancing battery performance and health by ensuring uniform heat dissipation and extending backup time through precise temperature control.
Implementation Method 1
a first cooling liquid channel... a second cooling liquid channel... wherein the first cooling liquid channel and the second cooling liquid channel are communicated with each other
Implementation Method 2
a pump and optional fan for temperature control, where a microcontroller regulates the cooling fluid flow
Implementation Method 3
a pump and optional fan for temperature control
Data Source
AI summary
Thermal management of a backup battery unit for datacenter applications is described. In one embodiment, a backup battery unit includes one or more battery cells immersed in cooling liquid contained in an immersion tank. The immersion tank includes a temperature sensor. The battery unit also includes a first direct-current to-direct-current (DC/DC) converter electronically coupled to the battery cells and to an external power source for converting and controlling a charging voltage obtained from the external power source to charge the battery cells. The backup battery unit also includes a cooling-liquid pump for driving cooling liquid to the battery cells. The backup battery unit also includes a microcontroller coupled to the temperature sensor, the first DC/DC converter, and the cooling-liquid pump. The microcontroller is configured to control operations of the cooling-liquid pump based on temperature data obtained from the temperature sensor and an electrical current of the first DC/DC converter.