IMPACT PROTECTION PLATE AND A METHOD OF PRODUCING SUCH A PLATE

Abstract

Impact protection plate for a vehicle comprising at least an impact layer with an outer surface for receiving the impact comprising at least one fiber reinforced thermoplastic polymer layer, and whereby the impact protection plate further comprises a spacer layer comprising at least one thermoplastic polymer layer, formed in a 3-dimensional shape with one or more protrusions, and whereby the impact layer and spacer layer are at least over part of their surface materially connected to each other forming one or more cavities between the impact layer and the spacer layer.

Claims

1. An impact protection plate for a vehicle comprising: at least an impact layer with an outer surface for receiving the impact comprising at least one fiber-reinforced thermoplastic polymer layer, characterized in that the impact protection plate further comprises a spacer layer comprising at least one thermoplastic polymer layer, formed in a 3-dimensional shape with one or more protrusions, and whereby the impact layer and spacer layer are at least over part of their surface materially connected to each other forming one or more cavities between the impact layer and the spacer layer.

2. The impact protection plate according to claim 1, whereby the thermoplastic polymer for either the impact layer and/or the spacer layer may be one chosen from the group of thermoplastic polymers, preferably polyolefin, like polypropylene, or polyamides, or polyesters, or thermoplastic polyurethane.

3. The impact protection plate according to claim 1, whereby the impact protection plate has at least 60% by weight, preferably at least 70% by weight, more preferably at least 80% by weight of fiber.

4. The impact protection plate according to claim 1, whereby the spacer layer comprises reinforced fibers, preferably the fiber content of the layer is not more than 50% by weight, more preferably between 20% and 35% by weight.

5. The impact protection plate according to claim 1, whereby the one or more protrusions are a wavelike pattern of alternating elevations and depressions forming ribs or beading, preferably with a cross section profile in a saw-tooth, trapezoidal, sinusoidal or toroidal bead shape, or a combination of such cross sectional profile shapes.

6. The impact protection plate according to claim 1, whereby the one or more protrusions are discrete elevations, preferably the shape of the elevations are in a dome, cone, pyramidal, or egg-box shape.

7. The impact protection plate according to claim 1, whereby the cavity comprises at least one venting hole through one of the adjacent layers.

8. The impact protection plate according to claim 1, whereby the impact layer comprises at least one sheet of at least one of short fibers, long fibers, woven, knitted, non-crimp fabric, textile or unidirectional fibers and or filaments embedded in a thermoplastic polymer material.

9. The impact protection plate according to claim 1, whereby the impact layer is a multilayer material, with at least a core layer made of at least one fiber reinforced thermoplastic polymer, further comprising at least one skin layer made of unidirectional tapes, organo sheets or fiber reinforced material embedded in thermoplastic polymer.

10. The impact protection plate according to claim 1, claims whereby the reinforcement fibers is at least one of glass fibers, carbon fiber, aramid fibers, basalt fibers, or cellulose based fibers or a mixture of such materials.

11. The impact protection plate according to claim 1, whereby at least one of the components, preferably all, are based on recycled or reclaimed origin.

12. A method of producing the impact plate according to claim 1, comprising: bringing a heated sheet of thermoplastic material for the spacer layer in one part of a two part compression style mold, preferably the lower tool part, and vacuum forming the thermoplastic outer layer against the mold surface by applying vacuum through the mold surface, and bringing a heated sheet for the impact layer onto the thus formed spacer layer in the lower mold, with both layers still hot enough to be draped, and closing the top mold to create a contact between both layers at dedicated areas to create a material connection between the layers while both layers are still sufficiently heated to allow bonding, whereby during and/or after the closing of the mold a reactive or nonreactive fluid or fluid mixture or gas is blown between both layers inside the cavities with one or more needle type channels such that cavity shape is maintained and one or more permanent venting holes are created after retraction of the needle at the end of the molding step.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions.

[0075] FIG. 1 is showing a car with an example for an impact protection plate according to the invention.

[0076] FIG. 2 is showing a cut out section of an impact protection plate according to the invention.

[0077] FIG. 3 is showing possible cross section profiles for protrusions in the spacer layer

[0078] FIG. 4 is showing alternative protrusions for the spacer layer.

[0079] FIG. 5 is showing the process of making the impact protection plate according to the invention.

[0080] It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION

[0081] FIG. 1 is showing a schematically the use of the impact protection plate according to the invention on a vehicle as a battery impact protection plate. A car body 1 and wheels 2 are indicating the normal layout of a passenger car. Underneath the passenger compartment a battery housing 3 with the cells or modules for the vehicle traction is placed. Battery housing including battery cells or modules are heavy structures, part because of the batteries themselves, but also because the housing is made of a solid metal to prevent damaging of the content. In the lower area the cooling plates may be placed. Newer designs combine the lower road facing panel of the battery housing, with the cooling plate function. The lower surface of the battery housing might even mirror and incorporate the shape of the cooling plates.(not shown)

[0082] Placing the cooling plate underneath the battery cells or modules, and combining it directly or indirectly with the lower panel of the battery housing bears a mayor risk. An impact might damage the lower surface of the cooling plate and impairs the cooling function, increasing the risk of an overheating battery system. However even without the risk of damage the lower surface of the battery box is exposed to draft underneath the surface of the car both during driving and at a standstill, while also the heat of surfaces like tarmac in the summer sun, might have an increased temperature and prevent the proper cooling of the batteries. In particularly when the car is not in use the battery temperature controls are not running either, hence the battery may be prone to extreme temperatures both high and low. The optimal battery operating temp is between 25 and 30° C., max 35° C.

[0083] Underneath the battery housing, an impact protection plate 4 according to the invention is placed with an impact layer 5 and a spacer layer 6 formed in a 3-dimensional shape with multiple protrusions. The spacer layer may be material connected to the impact plate on those areas of the layer that are closest to the surface of the other layer, forming closed cavities between both layers at the areas of the protrusions. The closed cavities work like air pockets, which provide thermal insulation. Surprisingly, also a lower amount of air pockets placed such that the area between elevations is enclosed between elevations and the opposite surface of the vehicle, may also create zones with standing air providing additional insulation. Hence not the full surface needs coverage with protrusions.

[0084] Surprisingly, the combination of the impact plate and the spacer layer is not only guiding the plate impact to the cage around the battery cells and/or to cooling plate areas that are void of running liquid but the insulation obtained by the cavities forming air pockets 7 provide enough thermal insulation to maintain a stable temperature in the battery housing.

[0085] The plate may be placed against the body of the battery housing or the any other car part that needs impact protection and might benefit from additional thermal insulation, such that no draft can run between the impact protection plate and the lower surface of the part to be protected. Preferably the ends of the impact layer are extended and shaped such that they may form a tray for the spacer layer. In particularly such that the impact protection plate may be mounted mainly by means for mounting connected to the impact layer solely.

[0086] The spacer layer may be fully covering the surface facing the part to be protected or the impact plate may be extending over the full surface of the car body area while only in the areas in need for additional thermal insulation the spacer layer is applied to create local insulating areas. Placing the part only where needed saves material and weight.

[0087] Preferably the part may be mounted to the car with a slight air gap of at least 2 mm between the spacer plate and the opposite surface.

[0088] FIG. 2 is showing as example a part of an impact protection plate 4 with the spacer layer 6 having trapezoidal corrugations, whereby the flat surface is in contact with the underlying impact layer 5. A trapezoidal cross section has the benefit that the contacting surfaces between the layer is larger and enables a stronger binding between the layers compared to a sinusoidal corrugated layer. This may not only optimize the lamination between the layers, but also increases the stiffness of the impact layer 5. The impact layer 5 is shown here an example of a sandwich structure, having two cover layers 8 and a core layer 9.

[0089] FIG. 3 examples of possible protrusions in the form of corrugations. The corrugations may be any cross section of saw tooth A, trapezoidal B, sinusoidal C or toroidal bead profile D or a combination of such cross section profiles. Preferably the cross section might be rounded or trapezoid. In the figure is also recognizable that the corrugations are not necessary directly following each other, corrugation free areas may be placed in between corrugated areas.

[0090] FIG. 4 is showing an example of alternative protrusions in the spacer layer in the form of discrete elevations in this case pyramidal or cone like shape with rounded top areas, defined as those areas of the spacer layer the furthers away from the impact layer. Showing cavities 7.

[0091] FIG. 5 is showing schematically the process of producing the impact protection plate according to the invention.

[0092] Method of producing the impact protection plate according the invention with at least the steps of: [0093] B. Bringing a heated sheet A of thermoplastic material for the spacer layer 6 in one part of a two part compression style mold 13,14, preferably the lower tool part 14, and vacuum forming the thermoplastic spacer layer against the mold surface by applying vacuum 15 through the mold surface, and [0094] D. Bringing a heated sheet 17 for the impact layer 5 onto the thus formed spacer layer 6 in the lower mold 14, with both layers still hot enough to be draped, and closing the top mold 13 to create a contact between both layers at dedicated areas to create a material connection between the layers while both layers are still sufficiently heated to allow bonding, whereby during the closing of the mold a fluid or gas is blown between both layers inside the cavities with a needle type channel 15, 16 to maintain the cavity shape, prevent sagging of either layer, and creating a permanent venting hole in the cavities after retraction of the needle at the end of the molding step.

[0095] The spacer layer 6 and the impact layer 5 may be heated in a separate step A and B. For instance by an infrared oven indicated with 12, or 17, depending on the thickness and the material used the layer can be heated from both sides or only from one side. The material should be soft enough to drape inside a mold without breaking or cracking.

[0096] Alternatively the impact layer 5 and or the spacer layer 5 is produced with a method known in the art and the still hot sheet material is directly used in the molding steps. These methods might be for instance an injection molding process, D-LFT process or compression molding process.

[0097] The hot spacer layer 6 is placed on top of a lower mold 14 and immediate while still warm, vacuum molded into the final shape for the spacer layer, the vacuum may be achieved with channels 15 within the lower mold connecting with the mold surface. In particularly in the areas furthers from the plane of the initial material layer on top of the mold. A slight thinning of the side walls within the protrusions may be occurring but need to be controlled to prevent creating holes in the spacer layer.

[0098] Optimally, the process is timed such that the hot impact layer is placed on top of the vacuum formed spacer layer, while the spacer layer is still warm. Having both layers still hot or at least warm improves the lamination of both layers, with lamination a material bonding between both layers is meant.

[0099] The impact layer 5 is placed on top of the formed spacer layer 6 in direct contact. At least one air supplying tube, 16 or 15, is put between the 2 layers either from the side 16 or from underneath 15 such that a fluid preferably air can be blown inside the cavities during the closing and final molding step of the part. The tubes may be fine and preferably needle shaped to be able to subtract the tubes, for instance just before or during demolding, while leaving a tiny hole. The fluid is blown inside the cavity such that the lower spacer layer is not pulled up again and at the same to time to prevent the impact layer from sagging inside the cavities. A further advantage is that with a slight overpressure inside the cavities the single protrusions are not collapsing during the cooling phase. By maintaining the tiny holes in the cavity a pressure compensation during the use of the part is given.

[0100] The surface of the impact layer facing away from the spacer, may also be formed in a 3-D shape, albeit staying close to an overall flat plane, for instance to create an aerodynamic surface and or to include small ribs to further increase the stiffness of the layer and thus the part overall.

[0101] The foregoing disclosure is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description, for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed inventions require more features than expressly recited. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention. Further, the embodiments of the present invention described herein include components, methods, processes, systems, and/or apparatus substantially as depicted and described herein, including various sub-combinations and subsets thereof. Accordingly, one of skill in the art will appreciate that would be possible to provide for some features of the embodiments of the present invention without providing others. Stated differently, any one or more of the aspects, features, elements, means, or embodiments as disclosed herein may be combined with any one or more other aspects, features, elements, means, or embodiments as disclosed herein.