Patent Application
20200403195
The present disclosure relates to thermal protection for an energy storage device and, in particular, to a thermal runaway shield for the energy storage device (e.g., a battery) to prevent thermal runaway propagation.
Lithium-Ion (“Li-Ion”) 18650 cells (and other batteries) have a slight chance of spontaneously shorting, which heats the interior gradually until a separator film within the cell melts, resulting in an internal short. Consequently, an explosive release of thermal energy can be triggered. The explosion can cause an end cap of the shorted cell to rupture. A flare briefly emerges (e.g., of around 1 second) from that ruptured end cap. For a minute or so, the cell's materials combust, releasing heat and driving the shorted cell to about 500 degrees Celsius (“C”) or greater.
If there are any neighboring cells that are consequently heated near or above a critical temperature (e.g., around 130° C.), the neighboring cells can also short with the same consequences causing additional explosions and ruptures; hence giving the well-known problem of thermal runaway propagation. To combat thermal runaway, Telsa, Inc. equips their Tesla's electric automobiles with an active cooling system to prevent thermal runaway propagation of their installed battery cells.
However, there is a desire to seek a passive solution suitable for battery packs of arbitrary cell sizes and shapes. Therefore, there exists a need for a novel system, method, and apparatus for preventing thermal runaway propagation for cells in an energy storage device.
An apparatus for shipping or storage of Li-ion batteries is disclosed. The apparatus for shipping or storage of Li-ion batteries comprises a sealable outer bag fabricated from heat-resistant, permeable fabric, a first flexible thermal runaway shield (“TRS”) fabricated from low-permeability film configured to line a first inside surface of the outer bag, a second flexible TRS fabricated from low-permeability film configured to line a second inside surface of the outer bag, and at least one Li-ion battery configured to be disposed between the first flexible TRS and the second TRS of the sealable outer bag to provide a sealed outer bag.
In accordance to another aspect of the present disclosure, the first flexible TRS is configured to wrap around a first Li-ion battery, the second flexible TRS is configured to wrap around a second Li-ion battery, and the sealable outer bag is configured to wrap around the first flexible TRS and the second TRS to provide a TRS sealed battery pack.
In accordance to another aspect of the present disclosure, the sealable outer bag includes a slit on each side of the bag.
In yet another aspect of the present disclosure, the apparatus for shipping or storage of Li-ion batteries comprises a sealable flexible thermal runaway shield (“TRS”) bag fabricated from low-permeability film configured to store at least one Li-ion battery, and a sealable outer bag fabricated from heat-resistant, permeable fabric configured to store the sealable flexible TRS bag.
In accordance to another aspect of the present disclosure, the flexible TRS includes a cavity to enclose elements for heat dissipation including water-based coolant.
In accordance to yet another aspect of the present disclosure, the apparatus for shipping or storage of Li-ion batteries comprises a sealable outer bag fabricated from heat-resistant, permeable fabric. a first flexible thermal runaway shield (“TRS”) fabricated from low-permeability film configured to line a first inside surface of the outer bag, a second flexible TRS fabricated from low-permeability film configured to line a second inside surface of the outer bag, a rigid divider configured to separate an interior of the sealable outer bag into a first compartment and a second compartment, a first sealable flexible TRS bag fabricated from low-permeability film configured to enclose at least one Li-ion battery within a first compartment of the sealable outer bag, and a second sealable flexible TRS bag fabricated from low-permeability film configured to enclose at least one other Li-ion battery within a second compartment of the sealable outer bag.
Other advantages of the disclosed apparatus for shipping and storage of Li-ion batteries will be readily apparent from the description of the drawings and detailed description.
The foregoing and other objects, aspects, and advantages of the present disclosure can be better understood from the following detailed description of various embodiments of the present disclosure when taken in conjunction with the accompanying drawings as follows.
In the following detailed description of the embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration of specific embodiments in which the present disclosure may be practiced. It is appreciated that the terms “a” or “an,” as used herein, are defined as one or more than one. Also, unless stated otherwise, terms such as “first”, “second”, “third”, etc. are used to distinguish between elements such terms describe. These terms are not necessarily intended to indicate temporal or prioritization of such elements.
The outer bag 19 receives the wrapped inner bag 49. The outer bag 19 is fabricated from heat-resistant, permeable fabric that permits controlled release of gas from any thermal event. Materials such as Nomex, Kevlar, or other heat resistant material can be used to manufacture the outer bag 19. The outer bag 19 affords controlled release of gas but contains flame and ejecta that can be generated in a thermal runaway event. The outer bag 19 is a closable bag and includes fasteners 48 attached to the outer bag 19 that can be folded over to seal the inner bag 19. The fasteners 48 can be made of Velcro or other suitable sealing mechanism. Once sealed, the outer bag 19 can be further wrapped to form a wrapped package substantially shaped and larger than the unprotected unwrapped energy cells as the energy cells are now wrapped and protected in the TRS outer bag liners 14 and the outer bag 19. In accordance to another embodiment of the present disclosure, slits 16 are located on the sides of the outer bag 19 to further enhance the permeability of the outer bag 19 during a thermal runaway event. The slits 16 can be fabricated from high temperature fiberglass material or other suitable material that can withstand high temperatures.
In accordance to an embodiment of the present disclosure, the rigid exterior thermal runaway shield assembly 34 includes a pliable thermal runaway shield 24 core with a rigid thermal runaway shield 36 attached to each side of the pliable thermal runaway shield 24. The rigid thermal runaway shields 36 reduce heat transfer by blocking heat transfer through the rigid thermal runaway shields 36. Rigidity can be imparted to the pliable thermal runaway shield 24 by a thin sheet or sheets of phenolic/paper laminate or similar heat-resistant material. In accordance to an embodiment of the present disclosure, the rigid exterior thermal runaway shield assembly 34 includes a pliable thermal runaway shield 24 sandwiched between two rigid thermal runaway shields 36. A secure attachment of the rigid exterior thermal runaway shield assembly 34 can be achieved by means of pressure-sensitive adhesive, rivets, or a combination of adhesives and rivets. The pliable thermal runaway shield 24 core is fabricated from low-permeability film. The low-permeability film encloses elements for heat dissipation that includes water-based coolant, wicking mechanism to distribute coolant either in a woven or nonwoven configuration. The wicking material can be made from Nomex, Kevlar, carbon fiber veil, or other heat-resistant material.
In accordance to another embodiment of the present disclosure, the pliable exterior thermal runaway shield assembly 32 includes a rigid thermal runaway shield 36 with a pliable thermal runaway shield 24 attached to each face of the rigid thermal runaway shield 36. The rigid thermal runaway shield 36 reduces heat transfer by blocking heat transfer through the rigid thermal runaway shield 36. Rigidity can be imparted to the pliable thermal runaway shield 24 by a thin sheet or sheets of phenolic/paper laminate or similar heat-resistant material. In accordance to an embodiment of the present disclosure, the pliable exterior thermal runaway shield assembly 32 includes a rigid thermal runaway shield 36 sandwiched between two pliable thermal runaway shields 24. A secure attachment of the pliable exterior rigid thermal runaway shield assembly 32 can be achieved by means of pressure-sensitive adhesive, rivets, or a combination of adhesives and rivets. The pliable thermal runaway shield 24 is fabricated from low-permeability film. The low-permeability film encloses elements for heat dissipation that includes water-based coolant, wicking mechanism to distribute coolant either in a woven or nonwoven configuration. The wicking material can be made from Nomex, Kevlar, carbon fiber veil, or other heat-resistant material. During a thermal runaway incident, the water-based coolant is converted to a gaseous state as the coolant absorbs the heat generated in the thermal runaway incident. Moreover, the wicking mechanism can serve as a coolant resorvior for keeping the liquid in the affected area for converting the coolant to a gaseous state when adequate heat energy is released from the affected ESD cells.
In a further embodiment of the present disclosure, there is at least one divider that is substantially sized approximate to the enclosure base and is placed horizontally inside at the top and at the bottom of the TRS enclosure. The divider affords additional protection from expanding gases and debris during a thermal runaway incident. The divider can be flexible, rigid, or a combination. Referring to
While the present disclosure has been described with reference to certain preferred embodiments or methods, it is to be understood that the present disclosure is not limited to such specific embodiments or methods. Rather, it is the inventor's contention that the disclosure be understood and construed in its broadest meaning as reflected by the following claims. Thus, these claims are to be understood as incorporating not only the preferred methods described herein but all those other and further alterations and modifications as would be apparent to those of ordinary skill in the art.
This application claims priority to a provisional patent application, entitled “Thermal Solutions for Shipping Li-Ion Battery Packs/Cells”, filed on Jun. 24, 2019 and having application No. 62/865,719. Said application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62865719 | Jun 2019 | US |
