Battery pack for energy storage devices
Battery packs for high energy density batteries (cells), particularly arrays of such batteries are described herein. The battery packs include a microfibrous media (MFM)-phase change materials (PCM) composite block and one or more active cooling structures. The MFM is typically sintered to the active cooling structures. The battery packs may contain more than one MFM-PCM composite block. Additionally or alternatively, the MFM-PCM composite block may contain different layers containing different MFM-PCM composites, which have different functionalities. In a preferred embodiment, at least one layer contains a flame retardant PCM, while at least one other layer contains a PCM with a lower melting temperature. The cells may be arranged in a repeating square or equilateral triangle pattern, with one or more active cooling structures in the geometric center of the square or triangle.
1. A battery pack comprising a microfibrous media (MFM)-phase change materials (PCM) composite block, one or more cells, and one or more cooling tubes, channels or a combination thereof,
wherein the MFM is sintered to the cooling tubes and/or channels, and
wherein the cells are aligned parallel with the cooling tubes and/or channels, and
wherein the cells are aligned generally perpendicular to the planar direction of the MFM.
2. The battery pack of claim 1 , wherein the MFM-PCM composite block comprises a plurality of cylindrical holes and wherein the cells are in the holes.
3. The battery pack of claim 1 , comprising more than one MFM-PCM composite block, wherein each block contains the same or different materials.
4. The battery pack of claim 3 , wherein one or more of the MFM-PCM composite blocks contains multiple layers, and wherein at least one of the layers contains a different phase change material than the other layers.
5. The battery pack of claim 4 , wherein at least one layer contains a flame retardant PCM, and wherein the other layers contain a PCM with a lower melting point than the flame retardant PCM.
6. The battery pack of claim 5 , wherein the flame retardant PCM is a metal salt-based PCM.
7. The battery pack of claim 6 , wherein the flame retardant PCM is magnesium sulfate heptahydrate (MgSO 4 .7H 2 O).
8. The battery pack of claim 1 , wherein the PCM in at least one of the MFM-PCM composite block is selected from the group consisting of paraffin waxes, glycols, and fatty acids.
9. The battery pack of claim 1 , wherein the MFM in the MFM-PCM composite block has a thermal conductivity of at least 5 W/(m·K).
10. The battery pack of claim 9 , wherein the MFM has a volume fraction of at least 5%.
11. The battery pack of claim 1 , wherein the PCM comprises one or more carbon materials selected from the group consisting of graphite, carbon nanotubes, and carbon fibers.
12. The battery pack of claim 2 , wherein the holes are aligned in a repeating square or and equilateral triangle pattern.
13. The battery pack of claim 12 , wherein at least one of the cooling tubes or channels is located in the geometric center of each pattern.
14. The battery pack of claim 1 , comprising one or more cooling tubes, wherein the MFM is sintered to the one or more cooling tubes.
15. The battery pack of claim 1 , further comprising an upper end plate, a lower end plate or both.
16. The battery pack of claim 15 , wherein the end plates comprise channels that connect to one end of each of the cooling tubes or channels.
17. The battery pack of claim 15 , wherein the end plates comprise one or more venting holes that are open at one end and in contact with the cells at the opposite end.
18. The battery pack of claim 2 , wherein the cooling tubes comprise a cooling fluid selected from the group consisting of water, alcohol-water mixtures, salt-water solutions, and other refrigerants.
19. The battery pack of claim 5 , wherein the layer containing the flame retardant PCM is an outerlayer.
20. The battery pack of claim 1 , wherein the MFM comprises a metal.