Battery casing, battery system and electric vehicle

Abstract

The present invention relates to a battery housing (1) for accommodating a plurality of battery cells of a battery system, a battery system including the battery housing, and an electric vehicle including the battery system, wherein the battery housing includes a housing frame (20) forming an internal space (25) suitable for accommodating a plurality of battery cells of the battery system, wherein the housing frame (20) includes a sidewall (22) embedded in a plastic member (30), the plastic member including an outer plastic layer (32) covering an outer surface of the sidewall (22) and an inner plastic layer (34) covering an inner surface of the sidewall (22) opposite to the outer surface, and the battery housing further includes an insulating layer (36) also embedded in the plastic member (30).

Description

Technical Field

[0001] The present invention relates to a battery housing for accommodating multiple battery cells of a battery system, a battery system including such a housing, and an electric vehicle including such a battery system. Background Technology

[0002] In recent years, vehicles using electricity as a power source have been developed. An electric vehicle is a car powered by an electric motor using energy stored in a rechargeable battery. Electric vehicles can be powered solely by batteries or can take the form of a hybrid vehicle powered by, for example, a gasoline generator. Furthermore, vehicles can include a combination of an electric motor and a conventional internal combustion engine. Typically, an electric vehicle battery (EVB), or traction battery, is a battery used to provide power for the propulsion of a battery electric vehicle (BEV). Electric vehicle batteries differ from starter batteries, lighting batteries, and ignition batteries because they are designed to provide power for a continuous period of time. Rechargeable batteries, or secondary batteries, differ from primary batteries in that they can be repeatedly charged and discharged, while primary batteries only provide the irreversible conversion of chemical energy into electrical energy. Low-capacity rechargeable batteries are used as power sources for small electronic devices such as mobile phones, laptops, and cameras, while high-capacity rechargeable batteries are used as power sources for hybrid vehicles, etc.

[0003] Rechargeable batteries can be used as battery modules formed by multiple unit battery cells connected in series and / or parallel to provide high energy density, particularly for electric motor drives in hybrid vehicles. Depending on the required amount of power, to achieve a high-power rechargeable battery, a battery module can be formed by interconnecting the electrode terminals of multiple unit battery cells. The battery cells can be connected in series, parallel, or a hybrid of series and parallel to provide the desired voltage, capacity, or power density. The components of a battery pack include individual battery modules and interconnections that provide conductivity between them.

[0004] The mechanical integration of this battery pack, or more generally, the mechanical integration of a battery system, may require appropriate mechanical connections, such as between individual components of the battery module and between them and the vehicle's supporting structure. These connections must remain functional and secure throughout the average lifespan of the battery system. Furthermore, installation space and interchangeability requirements must be met, especially in mobile applications.

[0005] Mechanical integration of battery modules, or more generally battery systems, can be achieved by providing a housing or carrier frame and mounting the battery modules or more generally battery systems thereon. The battery cells or battery modules can be secured via mating recesses in the frame or by mechanical interconnects such as bolts or screws. Alternatively, the battery module can be defined by fastening side panels to the sides of the carrier frame. Furthermore, a cover plate can be fixed to the top and bottom of the battery module.

[0006] The carrier frame for the battery pack, or more generally the battery system, can be mounted to the vehicle's load-bearing structure. If the battery pack or more generally the battery system will be secured to the bottom of the vehicle, the mechanical connection can be established from the bottom side, for example, by bolts passing through the carrier frame of the battery pack. The frame is typically made of aluminum or aluminum alloy to reduce the overall weight of the structure.

[0007] Battery systems according to the prior art typically include a battery casing, which serves as an enclosure to seal the battery system relative to the environment and provide structural protection for the battery system components. The packaged battery system is usually installed as a single unit in its application environment, such as an electric vehicle. Therefore, replacing a defective system component, such as a defective battery sub-module, requires first disassembling the entire battery system and removing its casing. Even defects in small and / or inexpensive system components can at that point lead to the disassembly and replacement of the entire battery system, as well as its individual repair. Because high-capacity battery systems are expensive, large, and heavy, this process proves cumbersome, and storing large battery systems, for example, in a mechanic's shop becomes difficult.

[0008] According to existing technology, the casing of battery systems is made of metal or plastic, or a combination thereof. These battery casings serve as a housing for internal battery components (such as battery cells, electrical contactors, cooling systems, electronic monitoring systems, etc.). Furthermore, these battery casings protect the battery system in the event of an impact and contribute to the secure fastening of battery system components.

[0009] Plastic casings offer lower component costs but suffer from relatively low mechanical strength and limited protection. Metal casings introduce the risk of short circuits in the event of a collision, poor thermal insulation, and significantly higher costs. Furthermore, additional corrosion protection must be implemented. The additional electrical interfaces add complexity to battery sealing. A combination of metal and plastic casings suffers from insufficient thermal insulation.

[0010] Therefore, the object of the present invention is to overcome or reduce at least some of the disadvantages of the prior art and to provide a battery housing for a battery system that has improved thermal insulation and allows for the integration of each battery system component by maintaining mechanical robustness. Summary of the Invention

[0011] The embodiments of this disclosure seek to address at least one problem present in the prior art to some extent.

[0012] Specifically, a battery housing is provided for accommodating multiple battery cells of a battery system. The battery housing includes a housing frame having an internal space adapted to accommodate the multiple battery cells of the battery system, the housing frame including sidewalls. The sidewalls are embedded in a plastic member, the plastic member including an outer plastic layer covering an outer surface of the sidewall and an inner plastic layer covering an inner surface of the sidewall opposite to the outer surface. The battery housing further includes a heat-insulating layer also embedded in the plastic member.

[0013] The battery casing can be for, for example, a 48V battery, a traction battery for a hybrid electric vehicle (HEV), or a traction battery for an electric vehicle (EV). According to the invention, at least the sidewalls of the casing frame are embedded in a plastic member, thus the plastic member surrounds the sidewalls. The bottom and / or top walls of the casing frame, particularly the cover plate, can also be embedded in such a plastic member. According to the invention, not only the sidewalls of the casing frame but also the insulation layer are embedded in the plastic member, thus the plastic member also surrounds the insulation layer. Therefore, the plastic member covers both the inner and outer surfaces of the insulation layer. In other words, the plastic member can include a first layer covering the insulation layer on a first side and a second layer covering the insulation layer on a second side opposite to the first side. The outer and / or inner plastic layers can have a thickness, for example, four to eight times the thickness of the sidewalls of the casing frame. For example, the outer and / or inner plastic layers can have a thickness of 8 mm, and the sidewalls can have a thickness of 1 mm.

[0014] The insulation layer extends along the sidewalls, particularly parallel to them. Furthermore, this insulation layer can be provided for the top / bottom walls of the shell frame, and both the insulation layer and the top / bottom walls are also embedded in the plastic components. Thus, the entire shell frame can be embedded in the plastic components along with the insulation layer to be protected from heat on all sides.

[0015] The insulation layer protects the battery casing from elevated temperatures that could damage it. As the inventors have discovered, the combined structure of the plastic component and the casing frame can fail at high temperatures, particularly above 1000°C. Such temperatures can be generated by fuel ignition, heat exhaust flows from the battery cells housed within the casing in the event of a thermal runaway event, or by electric arcing between adjacent battery cells. Therefore, the insulation layer is adapted to withstand temperatures of 1000°C or higher. In particular, the insulation layer is adapted to withstand temperatures of 1000°C or higher for at least 5 minutes to protect the casing at least for such a time period. However, according to the invention, as illustrated, the insulation layer is not exposed to the outside or inside of the battery casing but is embedded within the plastic component. Thus, at least a portion of the plastic component, i.e., at least a thin plastic layer, covers the insulation layer relative to the outer or inner side of the battery casing. The plastic component can formally hold the embedded elements, particularly the insulation layer, in the desired position relative to the casing frame. This hybrid structure of multiple materials is particularly durable.

[0016] Plastic components can be attached (e.g., directly attached) to the housing frame, such as by bonding. A preferred connection between the plastic component and the frame can be achieved by overmolding or spraying the housing frame with the plastic component material. The plastic component can be coated. The plastic component can contain a thermosetting polymer. The plastic component can be formed by reaction injection molding (RIM), which provides a curing reaction. Using this RIM, the housing frame and insulation layer can be embedded in the same plastic component.

[0017] Typically, the insulation layer can be embedded in either the outer or inner plastic layer of a plastic component. Furthermore, multiple insulation layers can be provided, wherein, for example, at least one insulation layer can be embedded in the outer plastic layer and at least one insulation layer can be embedded in the inner plastic layer. According to one embodiment, the insulation layer is embedded in the outer plastic layer. Thus, the outer plastic layer surrounds the insulation layer such that a first layer of the outer plastic layer covers the outer side of the insulation layer, and a second layer of the outer plastic layer covers the inner side of the insulation layer. The insulation layer can be specifically arranged near the periphery of the outer plastic layer such that all structural elements of the battery housing are arranged inside the insulation layer. The insulation layer embedded in the outer plastic layer allows the insulation layer to shield the housing frame and any other components inside the insulation layer from heat from the outside (e.g., due to fuel ignition after a collision). The insulation layer embedded in the inner plastic layer allows the insulation layer to shield the housing frame and any other components outside the insulation layer from heat from the inside (e.g., thermal runaway events of the battery cells surrounded by the battery housing).

[0018] According to one embodiment, a first insulation layer is embedded in an outer plastic layer, and a second insulation layer is embedded in an inner plastic layer. The first insulation layer may be disposed near the periphery of the outer plastic layer, and the second insulation layer may be disposed near the periphery of the inner plastic layer. This embodiment allows the shielding housing frame and any other components disposed between the two insulation layers to be protected from heat from the interior (e.g., due to thermal runaway of the enclosed battery cell) and from heat from the exterior (e.g., to resist heat from fuel ignition after a collision).

[0019] According to one embodiment, the battery casing further includes a structural element embedded in a plastic component. This structural element can be another component that, along with the aforementioned casing frame, is shielded by an insulating layer. The structural element can be part of the casing frame. Such a structural element can contribute to the stability of the battery casing and is preferably also shielded by the insulating layer. According to a corresponding embodiment, the structural element is embedded in an outer plastic layer. Specifically, the structural element can be arranged between the insulating layer and the sidewalls of the casing frame, with the insulating layer also arranged within the outer plastic layer. In this way, the insulating layer can shield the structural element and the sidewalls from external heat.

[0020] According to one embodiment, the sidewalls are metallic. Specifically, the sidewalls can be made of steel or aluminum. The sidewalls and plastic components can form a combination of a metallic and a plastic housing frame. The plastic components can provide additional stability, allowing the housing frame to have a smaller thickness than a housing frame without such plastic components. This can save costs, as metallic materials are generally more expensive than the materials used for plastic components. In this case, the plastic components preferably also serve as electrical insulators to shield the conductive housing frame from the battery cells and / or external influences.

[0021] According to one embodiment, the plastic component comprises a plastic foam, particularly polyurethane foam. Furthermore, the plastic component can be composed of such foam. The plastic foam can be applied, for example, by reaction injection molding (RIM) to surround the shell frame and the insulation layer. The plastic foam can be cured after application to exhibit higher density and therefore greater stability.

[0022] According to one embodiment, the insulation layer comprises a fabric. For example, the fabric may comprise, or be composed of, ceramic and / or glass fibers. In particular, the insulation layer may comprise a fabric and a resin, wherein the fabric and resin are bonded together after curing to form the insulation layer. Such an insulation layer can be particularly heat-resistant, especially up to 1000°C and higher.

[0023] According to one embodiment, the battery housing includes a cover plate as a top wall of the housing frame and a plastic member embedded therein together with the top wall and the insulation layer. Therefore, the cover plate, as part of the housing frame, can also be embedded in the plastic member together with the insulation layer, such that the insulation layer can shield the cover plate from heat from the inside and / or outside of the battery housing, depending on the arrangement of the insulation layer. For example, the insulation layer can be arranged inside the top wall / cover plate to protect it from thermal runaway of the enclosed battery cells.

[0024] According to one embodiment, the battery casing includes an air layer disposed adjacent to the insulation layer between the insulation layer and the sidewalls, particularly in direct contact with the insulation layer. This air layer can further enhance thermal insulation. This air layer can be provided in the factory setting of the battery casing or can be formed later. In particular, this air layer can be formed due to the insulation layer being exposed to sufficient heat. Therefore, according to the embodiment, the insulation layer can be adapted to form such an air layer when exposed to sufficient heat. For example, when exposed to sufficient heat, i.e., when a predetermined temperature is reached or exceeded, the insulation layer can be adapted to expand. Furthermore, in this case, the insulation layer can be adapted to separate from the plastic component, thereby forming an air layer within the plastic component. This can be achieved by an insulation layer comprising the fabric described above.

[0025] According to one embodiment, the plastic component also serves as an electrical insulator. This can be achieved by including an electrically insulating plastic material (e.g., polyurethane foam as described above) or a plastic component composed of an electrically insulating plastic material (e.g., polyurethane foam as described above). In this way, the housing frame can shield current from the outside and / or inside, particularly current from the battery cell. This is useful if the housing frame is metallic or contains metal.

[0026] The present invention also relates to a battery system comprising the battery housing described above, wherein a plurality of battery cells are housed within the battery housing. The battery cells are then arranged within the interior space of a housing frame. The battery cells may be erected on the bottom wall of the housing frame. Specifically, the battery cells may be positioned in contact with a cooling plate disposed at or forming the bottom of the housing frame. The cooling plate may be part of the battery housing.

[0027] The present invention also relates to electric vehicles including the battery system described above. The electric vehicle may be a HEV or an EV. The battery system can be used as a traction battery for the electric vehicle.

[0028] Other aspects of the invention may be learned from the dependent claims or the following description. Attached Figure Description

[0029] Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, wherein:

[0030] Figure 1 A perspective view of a battery casing according to an embodiment of the present invention is shown;

[0031] Figure 2 It is along Figure 1 A sectional view taken from line II-II; and

[0032] Figure 3 A cross-sectional view of a battery casing according to an embodiment of the present invention is shown in part. Detailed Implementation

[0033] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. The effects and features of exemplary embodiments and their implementation methods will be described with reference to the drawings. In the drawings, the same reference numerals denote the same elements, and redundant descriptions are omitted. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] In the following description of embodiments of the invention, singular terms may include plural terms unless the context clearly indicates otherwise.

[0035] It will also be understood that the terms “including,” “contains,” “including…” and “comprising…” specify the presence of attributes, areas, fixed quantities, steps, processes, elements, components, and combinations thereof, but do not preclude the presence or addition of other attributes, areas, fixed quantities, steps, processes, elements, components, and combinations thereof.

[0036] The features of the inventive concept and methods for implementing it can be more readily understood by referring to the following detailed description of embodiments and accompanying drawings. In the following, exemplary embodiments will be described in more detail with reference to the accompanying drawings, in which the same reference numerals refer to the same elements throughout. However, the invention can be embodied in various different forms and should not be construed as limited to the embodiments shown herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey aspects and features of the invention to those skilled in the art. Therefore, processes, elements, and techniques not essential for a full understanding of the aspects and features of the invention by those skilled in the art may not be described.

[0037] For ease of explanation, spatial relation terms such as “below,” “under,” “below,” “below,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature and another element or feature as shown in the figures. It will be understood that, in addition to the orientations depicted in the figures, spatial relation terms are intended to cover other different orientations of the device in use or operation. For example, if the device in the figures is flipped, then the element described as “below,” “below,” or “below” other elements or features will be oriented “above” said other elements or features. Therefore, the example terms “below” and “below” can cover both above and below orientations. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation descriptors used herein should be interpreted accordingly.

[0038] It will be understood that when an element or coating is referred to as being "on" another element or coating, "connected to" or "attached to" another element or coating, it can be directly on, connected to or attached to the other element or coating, or there can be one or more intermediate elements or coatings. Furthermore, it will be understood that when an element or coating is referred to as being "between" two elements or coatings, it can be the only element or coating between the two elements or coatings, or there can be one or more intermediate elements or coatings.

[0039] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that terms, such as those defined in common dictionaries, shall be interpreted as having the meaning consistent with their meaning in the relevant field and / or the context of this specification, and shall not be interpreted in an idealized or overly formal sense, unless expressly defined herein.

[0040] exist Figure 1 The image shows a battery housing 1 according to the present invention. The battery housing 1 includes a housing frame 20 having an internal space 25 adapted to accommodate a plurality of battery cells (not shown) of a battery system. The housing frame 20 is rectangular in shape and includes four sidewalls 22, each sidewall being embedded in a plastic member 30. The plastic member 30 includes an outer plastic layer 32 covering the outer surface of the sidewall 22 and an inner plastic layer 34 covering the inner surface of the sidewall 22 opposite to the outer surface.

[0041] like Figure 1 As shown, the sidewall 22 of the housing frame 20 may include a plurality of alternately arranged recessed portions 27 and protruding portions 28. These portions may be smoothly connected by connecting portions 29, such as curved portions. In other embodiments, the sidewall 22 of the housing frame 20 may be flat, see [reference needed]. Figure 3 At the bottom 10 of the housing frame 20, a cooling plate 16 is arranged to cool the battery cells (not shown) to be disposed on the cooling plate 16. For example, the battery cells are positioned in contact with the cooling plate 16. Figure 1 As shown, the cooling plate 16 can form the bottom wall of the housing frame. Optionally, the cooling plate 16 can be arranged above the bottom wall 21 of the housing frame 20, as shown. Figure 3 As shown.

[0042] from Figure 2 and 3 As can be seen, the battery casing 1 also includes a heat insulation layer 36, which is also embedded in the plastic component 30. More precisely, the heat insulation layer 36 is embedded in the outer plastic layer 32. The battery casing 1 may further include structural elements 23 embedded in the plastic component 30. For example, such as... Figure 3 As shown, the battery housing 1 also includes a plurality of structural elements 23, which are also embedded in the outer plastic layer 32, for example, between the insulation layer 36 and the sidewall 22 of the housing frame 20. The structural elements 23 can provide further stability to the battery housing 1, but they are only optional and can be omitted.

[0043] The insulation layer 36 is disposed around the outer plastic layer 32, but is still covered by the outer plastic layer 32 relative to the outside, as can be seen in the figure. The insulation layer 36 comprises a fabric, such as a fabric comprising ceramic and / or glass fiber, which is preferably cured in a resin. The insulation layer 36 shields the sidewalls 22 and structural elements 23 from heat from outside the battery housing 1 (e.g., heat caused by a fire due to a collision with an electric vehicle (EV) carrying the battery housing 1 as part of its battery system). Any battery cells disposed in the interior space 25 are thus protected from the effects of said heat.

[0044] from Figure 3 As can be seen, not only the sidewall 22, but also the bottom wall 21 is embedded in the outer plastic layer 32 along with the insulation layer 36, which also extends along the bottom of the housing frame 20. Therefore, the bottom wall 21 of the housing frame 20 is also shielded.

[0045] Another insulating layer (not shown) may be provided as an embedded portion of the inner plastic layer 34, i.e., inside the sidewalls 22 and structural elements 23, to protect the sidewalls 22 and structural elements 23 from heat from within the battery housing 1 (e.g., heat resulting from thermal runaway events occurring in one or more battery cells). Furthermore, the battery housing 1 may further include a cover plate serving as the top wall of the housing frame 20, which is embedded in the plastic member together with the insulating layer. Additionally, the battery housing 1 may include an air layer disposed adjacent to the insulating layer 36 between the insulating layer 36 and the sidewalls 22. For example, the insulating layer 36 may be adapted to form such an air layer when subjected to sufficient heat.

[0046] Therefore, the insulation layer contributes to the safety of the battery casing / system. The insulation layer can withstand temperatures of 1000°C or higher for at least 5 minutes. Embedding the insulation layer within the plastic components allows for a particularly stable and durable structure. Furthermore, the insulation layer 36 can also serve as an electrical insulator. The battery casing can be manufactured by reaction injection molding of the plastic material (particularly PU foam) constituting the plastic components, such that the casing frame, insulation layer, and structural elements are embedded within the plastic components.

[0047] Figure Labels

[0048] 1. Battery casing

[0049] 10. Bottom of the shell frame

[0050] 16 Cooling Plates

[0051] 20 Shell Frame

[0052] 21 bottom wall

[0053] 22 Sidewalls

[0054] 23 Structural Components

[0055] 25 Interior Space

[0056] 27. Recessed portion

[0057] 28. Protruding part

[0058] 29. Connection Part

[0059] 30 Plastic components

[0060] 32. Outer plastic layer

[0061] 34. Inner plastic layer

[0062] 36 Insulation layer

Claims

1. A battery casing (1) for accommodating multiple battery cells of a battery system, comprising: The housing frame (20) has an internal space (25) suitable for accommodating multiple battery cells of the battery system, wherein, The housing frame (20) includes a sidewall (22) embedded in a plastic member (30), the plastic member including an outer plastic layer (32) covering the outer surface of the sidewall (22) and an inner plastic layer (34) covering the inner surface of the sidewall (22) opposite to the outer surface, the battery housing further including an insulating layer (36) also embedded in the plastic member (30). The plastic component (30) is formed by reaction injection molding such that the sidewall (22) and the insulation layer (36) are embedded in the plastic component (30).

2. The battery casing (1) according to claim 1, wherein, The insulation layer (36) is embedded in the outer plastic layer (32).

3. The battery casing (1) according to claim 2, wherein, The insulation layer (36) is embedded in the outer plastic layer (32) near the periphery of the outer plastic layer (32).

4. The battery casing (1) according to claim 1, wherein, The first insulation layer is embedded in the outer plastic layer (32), and the second insulation layer is embedded in the inner plastic layer (34).

5. The battery casing (1) according to claim 1, wherein, The battery casing (1) further includes a structural element (23) embedded in the plastic component (30).

6. The battery casing (1) according to claim 5, wherein, The structural element (23) is embedded in the outer plastic layer (32).

7. The battery casing (1) according to claim 6, wherein, The structural element (23) is located between the insulation layer (36) and the sidewall (22) of the shell frame (20).

8. The battery casing (1) according to claim 1, wherein, The sidewall (22) is a metallic sidewall.

9. The battery casing (1) according to claim 8, wherein, The sidewall (22) is made of steel or aluminum.

10. The battery casing (1) according to claim 1, wherein, The plastic component (30) comprises or is composed of polyurethane foam.

11. The battery casing (1) according to claim 1, wherein, The insulation layer (36) comprises fabric.

12. The battery casing (1) according to claim 11, wherein, The insulation layer (36) comprises a ceramic and / or glass fiber fabric.

13. The battery casing (1) according to claim 1, wherein, The battery housing (1) includes a cover plate, which serves as the top wall of the housing frame (20), and the cover plate is embedded in the plastic component (30) together with the heat insulation layer.

14. The battery casing (1) according to claim 1, wherein, The battery housing (1) includes an air layer disposed adjacent to the insulation layer (36) between the insulation layer (36) and the sidewall (22).

15. The battery casing (1) according to claim 14, wherein, The insulation layer (36) is adapted to form the air layer when subjected to sufficient heat.

16. The battery casing (1) according to claim 1, wherein, The insulation layer (36) also serves as an electrical insulation component.

17. A battery system comprising a battery housing (1) according to any one of claims 1 to 16, which houses a plurality of battery cells.

18. The battery system according to claim 17, wherein, The battery cell is positioned to contact the cooling plate (16).

19. An electric vehicle comprising a battery system according to any one of claims 17 to 18.

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