Flexible multilayer battery pack insulator for electric vehicle

Abstract

A flexible multilayer battery pack insulator for an electric vehicle has a multilayer wall comprising: a first layer of interwoven mineral material, the first layer having a first inner surface and a first outer surface; a first flame retardant coating bonded to the first outer surface; a second layer of interwoven mineral material, the second layer having a second inner surface and a second outer surface; a second flame retardant coating bonded to the second outer surface; and a silicone foam intermediate layer sandwiched between the first inner surface of the first layer and the second inner surface of the second layer.

Description

Technical Field

[0001] This utility model generally relates to thermal insulators for electric vehicle battery packs, and more specifically to thermal insulators for suppressing the initiation and propagation of flames between batteries within a battery pack module of an electric vehicle. Background Technology

[0002] In electric vehicles, including hybrid vehicles with an electric motor that operates intermittently when the internal combustion engine is off, the primary power source for running the vehicle is provided by one or more battery packs. For example... Figures 2A to 2C As shown in Figure 12, each battery pack includes multiple modules 14, and each module 14 contains multiple batteries 16 arranged in a stacked relationship and electrically connected in series or parallel. While the batteries 16 are well-suited to provide the power required to operate the vehicle as intended, unexpected and undesirable problems can occur, such as during charging or when the module is subjected to an impact (e.g., during a vehicle collision). For example, during charging, individual batteries 16 tend to expand, and if they expand excessively, high voltages can be generated between adjacent batteries 16, potentially causing damage to one or more batteries 16. The resulting damage reduces the performance and lifespan of the batteries 16 and the battery pack 12. Furthermore, the resulting damage can lead to thermal runaway between the batteries 16 and ultimately to thermal runaway between the modules 14, such as the propagation of a flame starting from a single module 14. Figure 2A ), and propagate to adjacent modules ( Figure 2B and Figure 2C ).

[0003] It is desirable to provide thermal insulation between individual batteries that inhibits damage to the batteries during battery expansion and further suppresses flame propagation between batteries and between battery modules, for example, in the event of damage to a single battery. In particular, it is desirable to prevent flame propagation between batteries and battery modules when exposed to a flame at a distance of approximately 25 mm at temperatures of 1000°C–1400°C for 10 minutes or longer. Utility Model Content

[0004] The purpose of this disclosure is to provide a flexible multilayer material for electric vehicle battery packs, which at least satisfies the requirement of suppressing flame propagation between batteries within a battery module, between battery modules, and from the battery pack for 10 minutes or longer at a temperature of 1000-1400°C.

[0005] Another object of this disclosure is to provide a flexible multilayer material for use between batteries in an electric vehicle battery pack, which has a thin, uncompressed low profile (thickness) to minimize the amount of space occupied by thermal insulators between the batteries and is economical in terms of manufacture and use.

[0006] One aspect of this invention provides a flexible multilayer battery pack insulator for electric vehicles, hereinafter referred to as the insulator, disposed between stacked batteries within the battery modules of a battery pack. The insulator has multiple layers of walls, including: a first layer of interwoven mineral material having a first inner surface and a first outer surface; a first flame-retardant coating bonded to the first outer surface; a second layer of interwoven mineral material having a second inner surface and a second outer surface; a second flame-retardant coating bonded to the second outer surface; and a silicone foam interlayer sandwiched between and abutting the first inner surface of the first layer and the second inner surface of the second layer.

[0007] According to another aspect of the present invention, the first flame-retardant coating and the second flame-retardant coating are one of silicone, acrylic or polymer.

[0008] According to another aspect of the present invention, the first layer and the second layer have a density of 50-1100 gsm.

[0009] According to another aspect of the present invention, the first flame-retardant coating and the second flame-retardant coating each have a thickness of 0.1 mm to 2.0 mm.

[0010] According to another aspect of this invention, the intermediate layer has a strength of 500 kg / m³. 3 Up to 1500 kg / m 3 The density.

[0011] According to another aspect of the present invention, the intermediate layer has a thickness of 0.5 mm to 12.5 mm.

[0012] According to another aspect of the present invention, the insulator may further include a polymer film encapsulating multiple walls.

[0013] According to another aspect of the present invention, the polymer film encapsulating the multi-walled structure has a thickness of 0.010-0.051 mm.

[0014] According to another aspect of the present invention, the interwoven mineral material of the first layer and the interwoven mineral material of the second layer are formed into one of a woven fabric, a knitted fabric or a nonwoven fabric.

[0015] According to another aspect of the present invention, the first layer, the second layer, and the intermediate layer may be quilted together with one of polymer yarn, coated mineral yarn, or uncoated mineral yarn. Attached Figure Description

[0016] In view of the following detailed description of the presently preferred embodiments and best modes, the appended claims and drawings, the above and other aspects, features and advantages will be readily apparent to those skilled in the art, wherein:

[0017] Figure 1 This is a schematic perspective view of an electric vehicle having a battery pack with a multilayer thermal insulator constructed according to one aspect of the present invention.

[0018] Figures 2A to 2C A schematic diagram of an electric vehicle battery pack according to the prior art is shown, which is experiencing thermal runaway, with flames emanating from the battery module ( Figure 2A The flame-initiated location between the individual batteries in the battery pack is at the location of the battery pack ( Figure 2B and 2C It propagates without obstruction among multiple batteries within multiple individual battery modules;

[0019] Figures 3A to 3C It is similar to Figures 2A to 2C The view shows an electric vehicle battery pack comprising a plurality of flexible multilayer battery pack insulators constructed according to one aspect of the present disclosure. The flexible multilayer battery pack insulators are disposed between each adjacent battery and suppress and prevent flame from escaping from within individual battery modules and the battery modules ( Figure 3A The thermal runaway condition between adjacent cells within the battery module spreads to multiple cells within the battery module and the entire battery pack. Figure 3B and 3C );

[0020] Figure 4 This is a schematic plan view of one of the insulators of a flexible multilayer battery pack constructed according to the present invention;

[0021] Figure 5 It is roughly along Figure 4 A cross-sectional view taken from line 5-5;

[0022] Figure 6 It is a flexible multilayer battery pack insulator constructed according to another aspect of this disclosure, similar to... Figure 4 The view shows the layers stitched together using a quilting technique;

[0023] Figure 7 It is roughly along Figure 6 A cross-sectional view taken from line 7-7;

[0024] Figure 8A This is a partial side view of the middle layer of the flexible multilayer battery insulator shown, in a relaxed, uncompressed state; and

[0025] Figure 8B It is similar to Figure 8A The view shows the middle layer in a compressed state. Detailed Implementation

[0026] Please refer to the attached diagram for more details. Figure 1An example of a motor vehicle, shown as an electric motor vehicle, also referred to as an electric vehicle (EV), is illustrated. This EV has a battery pack 12, such as a lithium-ion battery pack, configured with at least one insulating material according to one aspect of the present invention, shown as multiple insulating materials, also referred to as flexible multilayer battery pack insulators or thermal insulators 10. The EV battery pack 12 includes a housing member, also referred to as a housing or enclosure, defining a plurality of battery modules 14, each battery module containing a plurality of batteries 16 stacked on top of each other, and includes a high-voltage connector, battery interfaces such as low-voltage signal lines, high-voltage cables, and one or more buses electrically interconnecting the batteries 16 and battery modules 14 for operative communication, and optionally a cooling system with cooling pipes through which coolant can flow, as is generally known in EV battery packs. Unlike battery packs 12 without the plurality of thermal insulators 10 disclosed herein, this EV battery pack 12 is designed to withstand normal use, including abnormal or unusual conditions, such as in the event of a vehicle collision or other circumstances causing damage or impact to the battery pack 12 and ultimately to the batteries 16 in the battery modules 14. Figures 2A to 2C As shown), when multiple flexible thermal insulators 10 are disposed between each battery 16, thermal runaway originating from any one of the batteries 16 in the battery pack 12, such as Figures 3A to 3C As shown, by means of a flexible thermal insulator 10 associated with battery 16 and contained within a single battery 16 of an overheated and / or flame source, flame is prevented from propagating from the overheated and / or flame source battery 16 to adjacent batteries 16 for at least 10 minutes at an internal battery temperature of 1200-1400°C, and the outer surface temperature of the casing is kept below 200°C, preferably 150°C, for at least 10 minutes.

[0027] like Figures 3A to 3C As schematically shown, a thermal insulator 10 is arranged between each adjacent battery 16 to thermally separate and isolate the individual batteries 16 from each other, thereby providing thermal protection between adjacent batteries 16 to suppress the thermal condition of one battery 16 from affecting the performance of the adjacent batteries 16, and further protecting the batteries 16 from forces generated by the batteries 16 during expansion, such as during a charging event of the battery pack 12, and further protecting the batteries 16 from impact forces, such as those that may be experienced in a collision. The insulator 10 has a relatively thin, flexible multilayer wall 18, for example, having an uncompressed thickness (t) of from about 2.0 mm to about 5.0 mm. Figure 5The thickness is preferably about 2.5mm-3.5mm, and in one exemplary embodiment, it has an uncompressed thickness of 2.8mm. The wall 18 is thin and flexible and can be constructed and configured as needed, for example, it can be wrapped as a hollow tubular sleeve around a busbar, wire, pipe, connector, etc. Of course, as shown, it can also be used in sheet form, such as a flat planar sheet, to provide a protective barrier between adjacent batteries 16 to effectively thermally insulate each battery 16 from its adjacent batteries 16.

[0028] like Figure 5 As shown in the schematic cross-section, the composite wall 18 includes a first layer 20 of interwoven mineral material having opposing first outer and first inner surfaces, also referred to as first outer and first inner sides 20a, 20b. The composite wall 18 also includes a second layer 22 of interwoven mineral material having opposing second outer and second inner surfaces, also referred to as second outer and second inner sides 22a, 22b. Furthermore, the composite wall 18 includes a compressible foam intermediate layer 24 sandwiched, also referred to as occupying, between the first inner side 20b of the first layer 20 and the second inner side 22b of the second layer 22. It should be understood that when the term "inner side" refers to the first and second inner sides 20b, 22b, it is intended to identify the side facing inward toward the intermediate layer 24, and when the term "outer side" refers to the first and second outer sides 20a, 22a, it is intended to identify the side facing outward away from the intermediate layer 24.

[0029] To further enhance the fire resistance of wall 18 and thus further suppress the spread of flame from one cell 16 to an adjacent cell 16, a first flame-retardant coating 26 is directly bonded to the first outer surface 20a of the first layer 20, and a second flame-retardant coating 28 is directly bonded to the second outer surface 22a. The first flame-retardant coating 26 and the second flame-retardant coating 28 are made of silicone, acrylic, or a polymer, and each of the first flame-retardant coating 26 and the second flame-retardant coating 28 has a thickness of 0.1 mm to 2.0 mm.

[0030] To further enhance the fire resistance of wall 18 and improve the handling and assembly of thermal insulator 10 between adjacent batteries 16, wall 18 of thermal insulator 10 may include a polymer film 30 encapsulating a first layer 20 and a second layer 22 of multilayer wall 18, as well as an intermediate layer 24 sandwiched between the first layer 20 and the second layer 22. By utilizing the polymer film 30 encapsulating the first layer 20, the second layer 22, and the intermediate layer 24, the layers 20, 22, and 24 can avoid being held together by adhesives, thereby eliminating potential sources of flame fuel and further ensuring better airflow between the stacked layers 20, 22, and 24 and between wall 18 and polymer film 30, thus providing another source of air layer insulation. Polymer film 30 is relatively thin, having a thickness of 0.010-0.051 mm, and in one exemplary embodiment, a thickness of 0.1 mm, therefore not significantly affecting the total thickness t of thermal insulator 10. The polymer film 30 can be provided as a heat-shrinkable material, such that once the first layer 20, the second layer 22, and the intermediate layer 24 are encapsulated, the polymer film 30 can be heat-shrinkable to tightly hold and encapsulate layers 20, 22, and 24 in contact with each other. During manufacturing, the polymer film 30 can be folded around the first layer 20, the second layer 22, and the intermediate layer 24, and then heat-sealed along one or more edges to completely surround layers 20, 22, and 24, and then heat-shrinkable, as described above. In a non-limiting embodiment, the polymer film 30 is folded along a centerline, and the three edges are heat-sealed together to completely surround layers 20, 22, and 24, and then the polymer film 30 is heat-shrinkable to uniformly contact the first layer 20 and the second layer 22, with the intermediate layer 24 sandwiched therebetween.

[0031] The first layer 20 and the second layer 22 are formed of interwoven mineral materials. According to a preferred embodiment, the first layer 20 and the second layer 22 are formed of mineral materials including one of ceramic materials, glass fibers, silica, basalt, S-2 glass, and HR glass fibers, including intertwined fibers as nonwoven fabrics, or interlaced multifilament yarns as woven or knitted fabrics. In an exemplary embodiment, the first layer 20 and the second layer 22 are formed as silica fabric, and the first flame-retardant coating 26 and the second flame-retardant coating 28 are provided with silicone. The first layer 20 and the first flame-retardant coating 26 have a combined thickness of 0.4 mm, and the second layer 22 and the second flame-retardant coating 28 have a combined thickness of 0.4 mm.

[0032] In an exemplary embodiment, the intermediate layer 24 is formed of silicone foam, which is sandwiched to abut against the first inner surface 20b of the first layer 20 and the second inner surface 22b of the second layer 22. The intermediate layer 24 has a strength of 500 kg / m³. 3 -1500kg / m 3 The density is [not specified], and it has an uncompressed thickness t1 of 0.5-12.5 mm. In one exemplary embodiment, the intermediate layer 24 is formed to have an uncompressed thickness t1 of about 2.0 mm.

[0033] The compressible foam material of the intermediate layer 24 has compression and recovery properties relative to its uncompressed relaxation thickness t1, which extends over the width, also known as thickness, from one side of the intermediate layer 24 to the other, wherein, as Figure 8A and Figure 8B As shown, the compressible foam material 24 can be compressed to its relaxed uncompressed thickness t1 under an applied load of 2 MPa. Figure 8A ) 25%, and in another embodiment, the compression can reach up to 50% of the relaxed uncompressed thickness t1, to achieve a compressed thickness t2 ( Figure 8B The intermediate layer 24 allows the cells 16 to expand relative to each other, enabling adjacent cells 16 to expand toward each other without generating internal stress within the individually expanding cells 16, thereby preventing damage to the individual cells 16 during cyclic thermal events. Thus, as a non-limiting example, the performance of the individual cells 16 and the battery pack 10 remains unaffected by thermal events, such as those that might occur during a charging event.

[0034] According to another aspect of this disclosure, the insulator 10a may generally include, as described above, a first layer 20, a second layer 22, and an intermediate layer 24, but excluding the polymer film 30. The first layer 20, the second layer 22, and the intermediate layer 24 are formed as described above, and therefore require no further discussion. As a non-limiting example, such as Figure 6 and Figure 7 As shown, the first layer 20, the second layer 22, and the intermediate layer 24 are held together by a stitching process, such as a quilting process, rather than encapsulating the first layer 20, the second layer 22, and the intermediate layer 24 with a polymer film. The first layer 20, the second layer 22, and the intermediate layer 24 can remain separated from each other except where they are stitched together by stitches 32, thereby allowing air layers or air gaps to form between the first layer 20 and the intermediate layer 24, and between the second layer 22 and the intermediate layer 24, as discussed above with respect to the encapsulation embodiment. This improves the thermal insulation performance of the thermal insulator 10a. It should be appreciated that the stitches 32 formed in the quilting process can include multiple stitches of any desired pattern, spaced apart from each other to form multiple air gaps therebetween as needed, also referred to as cavitation or air layers.

[0035] Obviously, based on the above teachings, this utility model can be modified and varied in many ways. It is conceivable that all features of all claims and all embodiments can be combined with each other, as long as such combinations do not contradict each other. Therefore, it should be understood that within the scope of the appended claims, this utility model can be implemented in ways other than those specifically described.

Claims

1. A flexible multilayer battery pack insulator for electric vehicles, characterized in that, include: Multi-layer wall, the multi-layer wall comprising: A first layer having a first inner surface and a first outer surface; A first flame-retardant coating is bonded to the first outer surface; A second layer having a second inner surface and a second outer surface; A second flame-retardant coating is bonded to the second outer surface; and A silicone foam interlayer sandwiched between the first inner surface and the second inner surface.

2. The flexible multilayer battery pack insulator according to claim 1, characterized in that, The first flame-retardant coating and the second flame-retardant coating are made of silicone, acrylic, or a polymer.

3. The flexible multilayer battery pack insulator according to claim 2, characterized in that, The first and second layers have a density of 50-1100 gsm.

4. The flexible multilayer battery pack insulator according to claim 3, characterized in that, The first flame-retardant coating and the second flame-retardant coating each have a thickness of 0.1-2.0 mm.

5. The flexible multilayer battery pack insulator according to claim 4, characterized in that, The intermediate layer has a strength of 500-1500 kg / m³. 3 The density.

6. The flexible multilayer battery pack insulator according to claim 5, characterized in that, The intermediate layer has a thickness of 0.5-12.5 mm.

7. The flexible multilayer battery pack insulator according to claim 1, characterized in that, It also includes a polymer film that encapsulates the multilayer walls.

8. The flexible multilayer battery pack insulator according to claim 7, characterized in that, The polymer film has a thickness of 0.010-0.051 mm and is thermally shrinkable around the multilayer wall.

9. The flexible multilayer battery pack insulator according to claim 1, characterized in that, The first layer and the second layer are formed as one of woven mineral fabric, knitted mineral fabric or nonwoven mineral fabric.

10. The flexible multilayer battery pack insulator according to claim 1, characterized in that, The first layer, the second layer, and the intermediate layer are quilted together with one of polymer yarn, coated mineral yarn, or uncoated mineral yarn.

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