Battery pack cover

Abstract

A battery housing for a battery system. The system includes: a base configured to support a battery cell; and a cover configured to be sealed to the base to enclose the battery cells between the base and the cover, the cover including a non-metallic composite layer and a metal layer extending across an entire outer surface of the non-metallic composite layer. The metallic layer is configured to at least partially separate from the non-metallic composite layer in response to a thermal event within the battery housing to define an air gap between the metallic layer and the non-metallic composite layer.

Description

Technical Field

[0001] The present disclosure relates to a battery pack cover, and more particularly, to a battery pack cover configured as a housing for accommodating a battery module and a battery cell. Background Art

[0002] The information provided in this section is intended to generally introduce the background of the disclosure. The work of the currently named inventors is neither explicitly nor implicitly admitted to be prior art to the present disclosure to the extent it is described in this section and to the extent that it may not qualify as prior art at the time of filing.

[0003] An electric vehicle (EV), such as a battery electric vehicle (BEV), a hybrid vehicle, and / or a fuel cell vehicle, includes one or more motors and a battery system, and the battery system includes one or more battery cells, modules, and / or battery packs. The battery control module is used to control the charging and / or discharging of the battery system during charging and / or driving.

[0004] The battery module and / or battery pack is arranged in a housing including a base and a cover. The base and the cover are usually made of metal (such as steel or aluminum). In addition to providing structural support functions, the housing may also need to perform other functions, such as thermal insulation, fire protection and / or electromagnetic shielding. When the structural components are made of aluminum or steel, the structural components may be relatively heavy. Summary of the invention

[0005] The present disclosure includes, among other features, a battery housing for a battery system. The system includes: a base configured to support a battery cell; and a cover configured to seal to the base to enclose the battery cell between the base and the cover, the cover including a non-metallic composite layer and a metal layer extending over an entire outer surface of the non-metallic composite layer. The metal layer is configured to at least partially separate from the non-metallic composite layer in response to a thermal event within the battery housing to define an air gap between the metal layer and the non-metallic composite layer.

[0006] In further features, the metal layer is bonded to the non-metallic composite layer using an adhesive configured to release at least a portion of the metal layer from engagement with the non-metallic composite layer in response to a thermal event.

[0007] In further features, an insulating layer is located between the non-metallic composite layer and the metal layer.

[0008] In further features, the non-metallic composite layer includes carbon fibers and the insulating layer includes a glass fiber veil.

[0009] In further features, the non-metallic composite layer includes a flame retardant material.

[0010] In further features, the non-metallic composite layer includes a phenolic resin.

[0011] In further features, the non-metallic composite layer includes a flame retardant material combined with at least one of an epoxy composite and a polyester composite.

[0012] In further features, the cover also includes a baffle configured to extend into and abut the base when the cover is sealed to the base, the baffle including a reinforcing fiber strip.

[0013] In a further feature, the seal is located between the base and the cover, and the baffle is opposite the seal and located on the inner side of the seal.

[0014] In further features, the interior of the cover defines a plurality of receptacles configured to receive potting material between the battery cells.

[0015] The present disclosure also provides a battery housing for a battery system in various features. The system includes: a base; a plurality of battery cells spaced apart along the base; a cover above the plurality of battery cells, the cover including a non-metallic composite layer and a metal layer extending over the entire outer surface of the non-metallic composite layer, and an interior of the non-metallic composite layer defining a plurality of receiving portions; and a potting material located between the plurality of battery cells and extending into the plurality of receiving portions of the non-metallic composite layer.

[0016] In further features, the metal layer is bonded to the non-metallic composite layer using an adhesive configured to release at least a portion of the metal layer from engagement with the non-metallic composite layer in response to a thermal event to define an air gap between the metal layer and the non-metallic composite layer.

[0017] In further features, the present disclosure includes: a seal connecting the cover and the base; and a barrier of the cover between the seal and the plurality of battery cells.

[0018] In further features, the baffle includes a reinforcing fiber strip.

[0019] Among the various features, the present disclosure also includes a battery housing for a battery system. The system includes: a base including a base flange; a plurality of battery cells spaced apart along the base; a potting material between the plurality of battery cells; and a cover. The cover includes: a cover flange, the cover sealed to the base by a seal between the cover flange and the base flange; a plurality of receptacles defined in an interior of the cover, the potting material extending into the plurality of receptacles; a baffle extending into the base and beyond the base flange, the baffle being located between the seal and the plurality of battery cells; a non-metallic composite layer including a flame retardant material; and a metal layer secured over an exterior of the non-metallic composite layer using an adhesive, the adhesive being configured to release at least a portion of the metal layer in response to a thermal event within the battery housing to define an air gap between the metal layer and the non-metallic composite layer.

[0020] In further features, the baffle extends into the base at least 3.0 mm beyond the base flange.

[0021] In further features, the baffle includes a reinforcing fiber tape and an outer surface of the baffle faces the seal.

[0022] In further features, an outer surface of the baffle contacts the base.

[0023] In further features, the distal end of the baffle is rounded or flat in shape.

[0024] In further features, the plurality of receiving portions have a semicircular or circular cross-section.

[0025] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0027] Figure 1 An exemplary vehicle including a battery pack having a housing according to the present disclosure is shown;

[0028] Figure 2 is a cross-sectional side view of a battery pack according to the present disclosure, the battery pack including a plurality of battery modules arranged in a housing including a cover.

[0029] Figure 3 is a cross-sectional side view of an exemplary battery cell including a cathode electrode, an anode electrode, and a separator veil.

[0030] Figure 4 is a cross-sectional side view of a battery pack including another cover according to the present disclosure.

[0031] Figure 5A is a side view of the cover showing the metal layer of the cover bonded to the non-metallic composite layer of the cover using an adhesive.

[0032] Figure 5B The metal layer is shown separating from the non-metallic composite layer in response to a thermal event to define a gap between the metal layer and the non-metallic composite layer;

[0033] Figure 5C An insulating layer between the metal layer and the non-metal composite layer is shown; and

[0034] Figure 6 The fiber bands at the baffle of the non-metallic composite layer are shown.

[0035] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0036] The present disclosure relates to a housing for a battery pack or battery module. The housing includes a cover and a base, which is typically a tray for housing the battery pack / module. The housing provides structural rigidity, improves thermal runaway propagation (TRP) protection, and / or provides electromagnetic interference (EMI) shielding. In some examples, the cover includes a relatively lightweight non-metallic composite layer having a flame retardant material. The non-metallic composite layer is covered with a metal layer to provide EMI shielding. The metal layer is configured to separate from the non-metallic composite layer during a thermal event to define an air gap therebetween, thereby reducing heat transfer from the composite layer to the metal layer, which can keep the metal layer at a lower temperature relative to the composite layer at least in the early stages of the thermal event. In applications where the non-metallic composite layer includes carbon fibers, a glass veil or other insulating layer may be included between the non-metallic composite layer and the metal layer.

[0037] In some examples, the cover includes a baffle that extends into the base when the cover is sealed to the base. The baffle can extend into the base beyond a base flange of the base, for example 3 mm to 20 mm below the base flange. The cover is sealed to the base using a sealant. The sealant is shielded by the baffle to protect the sealant from thermal events originating from within the housing. The baffle is located between the sealant and the battery cells within the housing.

[0038] In some examples, the baffle may include reinforcing fibers to enhance the thermal and structural properties of the housing. The fibers may be continuous fibers, discontinuous fibers, or a mixture thereof, including materials such as chopped unidirectional tapes, nonwoven felts, and / or oriented long fiber melts. The chopped unidirectional tapes include reinforcing fibers attached to or embedded in a substrate or backing layer and a thermoplastic resin. In some examples, the reinforcing fibers are pre-impregnated with a thermoplastic polymer matrix of a non-metallic composite cover, the thermoplastic polymer matrix being selected from polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylene sulfide (PPS), polyetherimide (PEI), low melting point PEEK (LMPEEK or PAEK (e.g., TC1225 (Toray) and AE250 (Victrex)) and combinations thereof.

[0039] In some applications, the cover may include an internal receptacle configured to accommodate a potting material added between the battery modules. For example, the cross-section of the receptacle may be rectangular or spherical. The potting material expands within the receptacle and adheres to the inner surface of the receptacle. The fit between the potting material at the receptacle and the cover enhances the structural rigidity of the housing.

[0040] Figure 1An exemplary vehicle 10 is shown including a battery pack 20. The battery pack 20 includes a base 22 or tray configured to be mounted to the vehicle 10. A cover 26 according to the present disclosure is configured to be mounted to the base 22. The base 22 and cover 26 together provide a housing 30 for any suitable battery module 50.

[0041] Although the cover 26 is shown as a cover for a vehicle battery pack, the teachings of the present disclosure are also applicable to non-vehicle applications. For example, the cover 26 can be included in a non-vehicle battery pack. The cover 26 can include a housing configured to accommodate any suitable battery cell, such as a prismatic battery cell, a cylindrical battery cell. The cover 26 can be configured to cover all battery modules 50, such as Figure 1 The teachings of the present disclosure are equally applicable to the covers of the individual battery modules 50. Thus, the cover of each battery module 50 may include some or all of the features and characteristics of the cover 26 described herein.

[0042] Figure 2 is a cross-sectional view of a battery pack 20 including a plurality of battery modules 50. Any suitable number of battery modules may be included. Figure 2 Examples include battery modules 50 - 1 , 50 - 2 , 50 - 3 , 50 - 4 , and 50 -M, where M is any suitable integer greater than 1. Figure 3 Exemplary battery cells 60 are shown. Each battery module 50 includes any suitable number of battery cells 60. Figure 2 In the example of , each battery module 50 includes battery cells 60-1, 60-2, and 60-B, where B is an integer greater than 1. The battery cells 60 can be prismatic battery cells, cylindrical battery cells, or any other suitable type of battery cells. The battery modules 50 are spaced apart along the base 22. The potting material 62 fills the space between the battery modules 50, as further described herein.

[0043] exist Figure 3 In the example of , each battery cell 60 includes a cathode electrode 70, such as cathode electrodes 70-1, 70-2, ... and 70-C, where C is an integer greater than 1. The cathode electrode 70 includes a cathode active material layer 72 arranged on one side or both sides of the cathode current collector 74. The battery cell 60 includes an anode electrode 90, such as anode electrodes 90-1, 90-2, ... and 90-A, where A is an integer greater than 1. The anode electrode 90 includes an anode active material layer 92 arranged on one side or both sides of the anode current collector 94. The cathode electrode 70, the anode electrode 90 and the separator 80 are arranged in a predetermined order in the housing 66 including a thermoplastic composite laminate structure. For example, the separator 80 is arranged between the cathode electrode 70 and the anode electrode 90. The external battery tabs 76, 96 may be arranged on the same side, opposite sides and / or different sides of the current collectors 74, 94.

[0044] Re-reference Figure 2 , the base 22 includes a base flange 110 extending around the periphery of the base 22. The cover 26 includes a cover flange 122 extending around the periphery of the cover 26. When the cover 26 is located on the base 22, the cover flange 122 is opposite to the base flange 110. Between the base flange 110 and the cover flange 122 is a seal 130, which seals the cover 26 to the base 22 and seals the housing 30 closed.

[0045] The inner surface of the cover 26 defines a plurality of receptacles 140. The potting material 62 includes an upper portion 64 that extends into the receptacles 140 to interlock with the cover 26 and increase the structural rigidity of the housing 30. The receptacles 140 may have any suitable cross-sectional shape. For example, the receptacles 140 may have a cross-sectional shape such as Figure 2 Alternatively, the cover 26 may include a receiving portion 140', such as Figure 4 As shown, it has a semicircular or spherical shape. The rectangular-shaped receiving portion 140 may have a depth of about 3mm-10mm and a width of about 3mm-25mm. The semicircular receiving portion 140′ may have a depth of about 3mm-10mm and a width of about 3mm-30mm. The potting material 62 may be any suitable material, such as thermosetting plastics, foam, silicone rubber gel, epoxy resin, etc. The potting material 62 fills the gap between the battery modules 50. When the cover 26 is sealed to the base 22, the potting material 62 expands into the receiving portions 140, 140′ and hardens. The upper portion 64 of the potting material 62 within the receiving portions 140, 140′ adheres to the portion of the cover 26 that defines the receiving portions 140, 140′ to enhance the structural rigidity of the housing 30.

[0046] The cover 26 also includes a baffle 150 that extends around the interior of the cover 26. The baffle 150 includes a distal end 152 and an outer surface 154. When the cover 26 is sealed to the base 22, the baffle 150 extends into the base 22 and is surrounded by the base flange 110. In some applications, the outer surface 154 can contact the base 22, or be spaced apart therefrom so that the baffle 150 is closely adjacent to the base flange 110. The size, shape, and other configuration of the baffle 150 can be such that the baffle 150 extends any suitable distance X into the base 22, beyond the base flange 110. For example, the distance X can be approximately 3 mm-20 mm. The distal end 152 can have any suitable shape. For example, the distal end 152 can be planar, such as Figure 2 shown. Figure 4 The distal end 152' is shown as having a rounded shape. The rounded distal end 152' may have any suitable radius, such as 3 mm to 20 mm.

[0047] The baffle 150 is located between the seal 130 and the battery module 50. The baffle 150 acts as a barrier to protect the seal 130 from heat that may be generated by a thermal event within the housing 30. To strengthen the baffle 150, the baffle 150 may include reinforcing fibers 156, such as Figure 6 150. The fibers 156 may be oriented so that they extend along the length of the baffle 150. The fibers 156 may be included in a fiber band at or near the outer surface 154 of the baffle 150. The fibers 156 may be included throughout the baffle 150 to enhance thermal and structural performance. The reinforcing fibers 156 may be co-molded with the cover 26. During molding, a relatively high temperature, such as 20°C-50°C, may be maintained at and near the baffle 150 to increase the curing rate of the relatively thick baffle 150.

[0048] The cover 26 generally includes a non-metallic composite layer 160 and a metal layer 162 bonded to the outside of the non-metallic composite layer 160. The metal layer 162 may be bonded to the non-metallic composite layer 160 in any suitable manner, such as by using a Figure 5A The adhesive layer 164 is shown. The non-metallic composite layer 160 includes any suitable flame retardant material. For example, the non-metallic composite layer 160 may include a flame retardant phenolic resin. As another example, the non-metallic composite layer 160 may be made of a material that is not inherently flame retardant, such as an epoxy composite and / or a polyester composite, but combined with any suitable flame retardant material. The non-metallic composite layer 160 may be formed using any suitable process, such as compression molding or resin transfer molding (RTM). In order to promote the curing of the non-metallic composite layer at the baffle 150, the mold tool may be maintained at a temperature 20°C to 50°C higher than the tool temperature.

[0049] The metal layer 162 can be made of any suitable metal material, such as aluminum or steel. The metal layer 162 reinforces the cover 26 and acts as a Faraday shield to contain the electrical signal within the housing 30 and prevent the electrical signal from interfering with other electronic components of the vehicle 10. The metal layer 162 can have any suitable thickness, such as about 0.1 mm to about 1.0 mm. For example, the metal layer 162 is bonded to the non-metal composite layer 160 by the adhesive layer 164 at a temperature below 100° C. by applying a pressure of, for example, 50-500 psi.

[0050] refer to Figure 5B, the cover 26 is configured such that the metal layer 162 separates from the non-metallic composite layer 160 during a thermal event within the housing 30 to define an air gap 166 therebetween. Specifically, the adhesive layer 164 is configured to release the metal layer 162 from the cooperation with the non-metallic composite layer 160 in response to a thermal event. For example, the adhesive layer 164 may be configured to melt at a predetermined temperature corresponding to a temperature associated with a thermal event within the housing 30. The adhesive layer 164 may also be configured to release the metal layer 162 from the cooperation with the non-metallic composite layer 160 in response to stress applied to the adhesive layer 164 by the non-metallic composite layer 160 and / or the metal layer 162, which have different thermal expansion coefficients during a thermal event. Once the adhesive layer 164 fails or otherwise releases the metal layer 162, the metal layer 162 further expands due to its relatively high coefficient of thermal expansion (CLTE), and the metal layer 162 protrudes away from the non-metallic composite layer 160, whose CLTE is relatively low. The air gap 166 forms a thermal barrier, effectively maintaining the metal layer 162 at a lower temperature than the non-metallic composite layer 160 during a thermal event, for example, below 370°C.

[0051] Figure 5C An optional insulating layer 170 is shown between the non-metallic composite layer 160 and the metal layer 162. The insulating layer 170 may include, for example, a glass fiber veil. When the non-metallic composite layer 160 includes carbon fibers, the insulating layer 170 may be included to protect the metal layer 162, for example, from galvanic corrosion.

[0052] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because other modifications will become apparent after studying the drawings, the specification and the appended claims. It should be understood that one or more steps within a method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in the features of any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more embodiments to each other is still within the scope of the present disclosure.

[0053] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on," "above," "below," and "disposed." Unless explicitly described as "directly," when describing a relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship, in which there are no other intermediate elements between the first element and the second element, but can also be an indirect relationship, in which there are one or more intermediate elements (spatially or functionally) between the first element and the second element. As used herein, "at least one of A, B, and C" should be interpreted to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0054] In the drawings, the direction of the arrows, as indicated by the arrows, generally demonstrates the flow of information (e.g., data or instructions) of interest to the illustration. For example, when component A and component B exchange various information, but the information transmitted from component A to component B is relevant to the illustration, the arrow may be directed from component A to component B. This unidirectional arrow does not mean that no other information is transmitted from component B to component A. In addition, for information sent from component A to component B, component B may send a request or a receipt confirmation of the information to component A.

Claims

1. A battery housing for a battery system, comprising: a base configured to support a battery cell; as well as a cover configured to be sealed to the base to enclose the battery cell between the base and the cover, the cover comprising a non-metallic composite layer and a metal layer extending over an entire outer surface of the non-metallic composite layer; The metal layer is configured to at least partially separate from the non-metal composite layer in response to a thermal event within the battery housing to define an air gap between the metal layer and the non-metal composite layer.

2. The battery housing according to claim 1, wherein: The metal layer is bonded to the non-metallic composite layer using an adhesive, the adhesive being configured to release at least a portion of the metal layer from engagement with the non-metallic composite layer in response to the thermal event. 3 . The battery case according to claim 1 , further comprising an insulating layer between the non-metallic composite layer and the metal layer.

4. The battery case according to claim 3, wherein: The non-metallic composite layer comprises carbon fibers and the insulating layer comprises a glass fiber veil.

5. The battery housing according to claim 1, wherein: The non-metallic composite layer includes a flame retardant material.

6. The battery housing according to claim 1, wherein: The non-metallic composite layer includes phenolic resin.

7. The battery housing according to claim 1, wherein: The non-metallic composite layer includes a flame retardant material combined with at least one of an epoxy composite material and a polyester composite material.

8. The battery housing according to claim 1, wherein: The cover also includes a baffle configured to extend into and abut the base when the cover is sealed to the base, the baffle including a reinforcing fiber strip. 9 . The battery housing according to claim 8 , further comprising a sealing member between the base and the cover, wherein the baffle is opposite to the sealing member and is located on an inner side of the sealing member.

10. The battery housing according to claim 1, wherein: The interior of the cover defines a plurality of receiving portions configured to receive a potting material between the battery cells.

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