N14A-T006 TITLE: Development of a Safer Lithium-ion (Li-ion) Battery for Naval Aircraft Applications Through Thermal Management Design

TECHNOLOGY AREAS: Air Platform

OBJECTIVE: Develop and demonstrate a safe Lithium-ion (Li-ion) battery that is capable of preventing thermal runaway conditions between cells or group of cells by integrating novel thermal management technologies.

DESCRIPTION: Lithium batteries are composed of multiple individual cells connected in parallel and/or series depending on the specific application. If the desired outcome is to increase overall voltage or overall capacity, they are connected in series or parallel, respectively. If both increased power and capacity are required, the conformation of the cells becomes more complicated. In large aircraft batteries, there are a large number of risks in battery engineering, especially due to the power requirements aircrafts demand. Catastrophic failure by aircraft damage, fire damage, and battery explosion is one risk that has turned into an issue for aircraft Li-ion batteries. In addition, aircraft Li-ion batteries are operated in extreme environmental conditions. Adverse operating conditions can result in thermal runaway conditions due to failed cells and thereby limit the life expectancy of aircraft Li-ion batteries. Conventional thermal management technologies for dealing with safety and battery life may increase the overall size and weight of the battery which can ultimately eliminate the energy and power benefits derived from the use of Li-ion batteries on aircrafts. The key to avoiding these kinds of failures is to develop novel thermal management technologies such as passive techniques (advanced insulation), active techniques (heat pipes, working fluids), and light-weight structured materials.

The goal is to design an integrated battery pack system concept to develop a fully functional battery product. The integrated battery pack system should be designed in such a way that the proposed advanced thermal management technologies can support individual cell temperature monitoring and help prevent single cell thermal runaway conditions as well as limit/eliminate thermal failure propagation leading to cell/battery fratricide. The design should be capable of insulating cell-level thermal events to prevent thermal transfer, propagation between cells as well as the ability to dissipate heat faster to prevent failure. Single cells, depending on the electrode materials and design, may undergo high energetic release. The overall thermal management system must be designed so that in the event of thermal runaway conditions the propagation will be limited to the cell pack (threshold) or single cell (objective), thereby ensuring maximum safety for the battery in case of failure. The Li-ion product should be thermally stable over a wide temperature range (negative 18 degrees Celsius to 71 degrees Celsius operational and exposure to 85 degrees Celsius [4]), as well as meeting electrical needs of aircraft in relevant environment (shock test, vibration test, humidity test, transient drop test, etc.[4]).

PHASE I: Develop the proof of concept for a battery pack system ensuring maximum safety in case of thermal event leading to cell fratricide. Use state-of-the art modeling and simulation (M&S) tools for thermal management design and verify by demonstrating at cell/module level.

PHASE II: Develop a safer Li-ion battery prototype by integrating innovative thermal management technologies to demonstrate the response to failure mode in a lab environment.

PHASE III: Demonstrate the battery pack system that is thermally stable over a wide temperature range as well as meet the electrical needs of aircraft in operational environment, and transition the technology to the appropriate navy platforms (Ex. F/A-18E/F, H-60, and F-35).

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Li-ion batteries are one of the most prevalent commercial types of rechargeable batteries due to their superior properties such as very high energy and power density. Because of this they are gaining popularity in commercial aircraft applications.
Improvements made under this topic would be directly marketable to the commercial aviation fleet.

REFERENCES:
1. Bandhauer, T. M., Garimella, S., & Fuller, T. F. (2011). A Critical Review of Thermal Issues in Lithium-Ion Batteries. Journal of the Electrochemical Society, 158(3), R1-R25. doi:10.1149/1.3515880.

2. Ramadass, B., Haran, B., White, R., & Popov, B. N. (2002). Capacity fade of Sony 18650 cells cycled at elevated temperatures: Part I. Cycling performance. Journal of Power Sources, 112(2), 606-613. Retrieved from http://www.che.sc.edu/faculty/popov/drbnp/website/Publications_PDFs/Web51.pdf.

3. Spotnitz, R. & Franklin, J. (2003). Abuse behavior of high-power, lithium-ion cells. Journal of Power Sources, 113(1), 81-100. http://www.sciencedirect.com/science/article/pii/S0378775302004883.

4. MIL-PRF-29595A - Performance Specification: Batteries and Cells, Lithium, Aircraft, General Specification For (21 Apr 2011) [Superseding MIL-B-29595]. http://www.everyspec.com/MIL-PRF/MIL-PRF-010000-29999/MIL-PRF-29595A_32803/.