Thermal Tab Design for High-Capacity Li-Ion Battery Cooling
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Solution Overview
Problem
Lithium ion batteries face significant thermal management challenges during high C-rate discharge, as conventional cooling methods are ineffective due to thermal resistance and low thermal conductivity between layers, limiting their thickness and discharge rate.
Innovation Solution
Incorporating thermal tabs on the current collectors for enhanced heat transfer, combined with a heat transfer system using closed channels and a fluid circulation system controlled by a processor to maintain optimal temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods (convective natural cooling, forced air cooling, forced liquid cooling) are used, then surface area cooling is achieved, but thermal management effectiveness deteriorates due to high thermal resistance between layers and low thermal conductivity of separators
Solution Approach 1:
The invention segments the thermal management function by separating the electrode tab (for electrical connection) from the thermal tab (for thermal management). The thermal tab is a dedicated structure attached to the current collector that provides a direct thermal pathway from the battery core to the cooling system, bypassing the high-resistance separator layers. This segmentation allows independent optimization of electrical and thermal functions.
Solution Approach 2:
The thermal tab acts as an intermediary element between the heat-generating electrode and the cooling system. It provides a low-resistance thermal conduction path that mediates heat transfer from the battery interior to the external cooling plates, overcoming the thermal resistance of the separator layers that block conventional cooling approaches.
2Quantity of substance
If battery thickness is increased to achieve higher capacity, then energy density improves, but thermal management becomes more difficult due to increased internal heat generation and reduced cooling efficiency
Solution Approach 1:
The invention adds a new dimensional approach to thermal management by extending thermal tabs in multiple directions (laterally and vertically) from the current collector. This creates a three-dimensional thermal conduction network that can efficiently extract heat from thick battery configurations, allowing increased capacity without compromising thermal control.
3Volume of stationary object
If battery thickness is increased without increasing surface area, then energy density improves, but conventional cooling effectiveness deteriorates due to reduced surface-to-volume ratio
Solution Approach 1:
The thermal management function is segmented into multiple thermal tabs distributed throughout the battery structure rather than relying on a single large surface area. These distributed thermal tabs create multiple parallel heat extraction pathways, effectively increasing the thermal exchange surface area within the battery volume without increasing the external footprint.
4Power
If high C-rate discharge is implemented to achieve higher power output, then power delivery improves, but heat generation increases dramatically requiring more aggressive cooling
Solution Approach 1:
The thermal tab serves as a dedicated intermediary structure that facilitates rapid heat extraction during high-power discharge events. By providing a direct thermal conduction path from the current collector to the cooling system, it enables the battery to sustain high C-rate discharge without excessive temperature rise, as the thermal tab efficiently mediates the heat removal process.
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 allows for increased battery thickness without expanding surface area, enabling higher capacity and energy density, while effectively regulating temperature within the optimal range of 20-40°C, even at high discharge rates.
Implementation Method 1
The thermal tab is in thermal connection with the current collector and serves as a dedicated thermal pathway for heat transfer
Implementation Method 2
a heat transfer system for heat transfer with the thermal tab, wherein the heat transfer system includes a closed heat transfer channel for a heat transfer fluid
Data Source
AI summary
A lithium ion battery includes a cathode in electrical and thermal connection with a cathode current collector. The cathode current collector has an electrode tab. A separator is provided. An anode is in electrical and thermal connection with an anode current collector. The anode current collector has an electrode tab. At least one of the cathode current collector and the anode current collector comprises a thermal tab for heat transfer with the at least one current collector. The thermal tab is separated from the electrode tab. A method of operating a battery is also disclosed.