BATTERY HOUSING AND ITS USE IN ELECTRIC VEHICLES

Abstract

The present invention relates to a battery housing and to its use in electric vehicles.

Claims

1. A battery housing for an electric vehicle, wherein the housing comprises a cover and a floor which are joined to one another and the cover is joined to a vehicle body or a part of the vehicle body forms the cover of the housing, wherein the floor faces away from the vehicle body and the floor is obtained by pultrusion and is made of thermosetting plastic obtained from a reactive resin mixture and reinforced with endless fibers, wherein the fibers run transversely to the direction of travel of the vehicle.

2. The battery housing as claimed in claim 1, wherein the plastic comprises polyurethane.

3. The battery housing as claimed in claim 1, wherein the floor has hollow chambers.

4. The battery housing as claimed in claim 1, wherein the cover and the floor are joined by profiles and/or side parts made of metal.

5. The battery housing as claimed in claim 1, wherein the floor comprises of floor modules that are joined to one another and have joining sites.

6. The battery housing as claimed in claim 5, wherein the floor modules are additionally reinforced at the joining sites.

7. The battery housing as claimed in claim 1, wherein the floor is reinforced by struts and/or bracings arranged perpendicular to the floor.

8. The battery housing as claimed in claim 2, wherein the pultruded floor made of polyurethane as the plastic and reinforced with glass-based endless fibers has an axial flexural strength according to DIN EN ISO 14125 of 1100 to 1500 MPa, an axial compression modulus according to DIN EN ISO 14126 of 50 to 60 GPa, an axial interlaminar shear strength according to DIN EN ISO 14130 of 60 to 80 MPa, a shear modulus according to DIN EN ISO 15310 of 3 to 6 GPa, an axial tensile modulus according to DIN EN ISO 527-4 of 45 to 60 GPa, a transverse tensile modulus according to DIN EN ISO 527-4 of 10 to 15 GPa and/or a thermal conductivity according to DIN EN 993-14 of 0.1 to 0.7 W/m K.

9. The battery housing as claimed in claim 2, wherein the polyurethane reinforced with endless fibers has a density according to DIN EN ISO 1183 of 1.5 g/cm3 to 2.2 g/cm3.

10. The battery housing as claimed in claim 2, wherein the content of endless fibers is at least 40% by volume and at most 80% by volume in the polyurethane reinforced with endless fibers.

11. The battery housing as claimed in claim 2, wherein the polyurethane is obtained from a polyurethane reaction mixture consisting of a polyisocyanate component (A), a polyol component (B) consisting of b1) a mixture of at least two polyols, b2) 0-20% by weight, based on the total weight of (B), of one or more further isocyanate-reactive compounds distinct from b1), in the presence of b3) 0-5% by weight, based on the total weight of B), of one or more catalysts, b4) 0-20% by weight, based on the total weight of (B), of further assistant and/or additive substances, and 0.1-8% by weight, based on the total weight of (B), of at least one internal release agent (C).

12. An electric vehicle comprising a battery housing as claimed in claim 1, wherein the battery housing is attached in the vehicle in such a way that the endless fibers present in the floor of the housing are aligned transversely to the direction of travel of the electric vehicle.

Description

DESCRIPTION OF THE FIGURES

[0064] FIG. 1 shows part of a battery housing according to the invention without battery modules and control unit.

[0065] FIG. 2 is a detail section from FIG. 1 which is defined by the dashed circle in FIG. 1.

[0066] The battery housing has a base 1 and side walls 3 and 4 and also struts 5. The arrow 6 shows the direction of impact in the event of a side impact and the arrow 7 the direction of travel of the vehicle (not shown) in which the battery housing is located. The side parts may be joined to the cover (not shown) by means of the bores 8. Cables (not shown) may run through the recesses 9 and 9′, for example. The dashed circle in FIG. 1 shows the section shown in FIG. 2.

[0067] The base modules of the battery housing are joined to one another by a tongue and groove join 11. The screws 12 connect the struts to the floor of the battery housing.

[0068] The invention shall be more particularly elucidated with reference to the exemplary embodiments which follow.

EXAMPLES

[0069] The battery housing according to the invention is composed of [0070] a floor made of composite, pultruded hollow chamber profiles (unidirectionally aligned glass fibers embedded in a polyurethane matrix; fiber content 65 percent by volume) whose fibers are aligned perpendicularly to the direction of travel of the vehicle; the polyurethane-based pultruded profiles have a lower density than metal and therefore have a low weight; [0071] side parts composed of hollow chamber profiles made of steel; [0072] struts made of steel which connect two adjacent floor profiles and two opposite side parts; [0073] a lid composed of a polypropylene plate which seals the battery housing; [0074] battery modules and control unit.

[0075] The employed polyurethane system was:

TABLE-US-00001 Polyol component B: [% by weight] Glycerol-started triol, propoxylated, OHN = 235 mg KOH/g 28.47 Glycerol-started triol, propoxylated, OHN = 1050 mg 26.00 KOH/g Glycerol-started triol, propoxylated, OHN = 400 mg KOH/g 23.81 Propylene glycol-started diol, propoxylated, OHN = 9.79 28 mg KOH/g Propylene glycol-started diol, propoxylated, OHN = 9.26 515 mg KOH/g Diisooctyl 2,2′-[(dioctylstannylene)bis(thio)]diacetate 0.67 MOLSIV ® L-powder from UOP 2.00 Luvotrent ® TL HB 550 from Lehmann & Voss 4.00 Average OH number of component B 486 Nominal functionality of component B 2.73 Component A: Polymeric MDI having an NCO content of 31.5% and a 131 viscosity of 200 mPas at 25° C. (ISO 3219)

[0076] The pultruded profiles produced with the polyurethane system have the following physical properties: [0077] Axial flexural strength: about 1300 MPa (DIN EN ISO 14125) [0078] Axial compression modulus: about 53.5 GPa (DIN EN ISO 14126) [0079] Interlaminar axial shear strength: about 70 MPa (DIN EN ISO 14130) [0080] Thermal conductivity: about 0.5 W/m K (DIN EN 993-14) [0081] Density: about 2.1 g/cm.sup.3 (DIN EN ISO 1183) [0082] Transverse tensile modulus: about 12 GPa (DIN EN ISO 527-4) [0083] Axial tensile modulus: about 50 GPa (DIN EN ISO 527-4) [0084] Shear modulus: about 3.5 GPa (DIN EN ISO 15310)

[0085] The comparative battery housing consists of a profiled floor plate (“corrugated profile” for stiffening) made of die-cast aluminum, upon which the battery modules are secured. The battery modules are covered by a lid made of glass fiber-reinforced polypropylene. The floor plate projects laterally and thus has a greater area than the battery modules secured thereupon and therefore constitutes a lateral crumple zone which is intended to absorb the forces in the event of an impact through deformation.

[0086] The battery housing according to the invention was subjected to two different simulated crash cases (the so-called “China crush test” and “side pole impact test (35 km/h))(90° ” corresponding to the NCAP tests for crash load cases) and compared with the comparative battery housing described above from the prior art.

[0087] In the so-called China crush test, the battery housing including the battery modules and the control unit is pressed (laterally and centrally) against a pole having a diameter of 150 mm at a speed of 1 m/s and the resulting deformation is observed. Battery modules should not be damaged upon achieving a force of 120 kN.

[0088] The simulation of the China crush test with the battery housing according to the invention showed that no damage to the battery/the battery modules occurred at 120 kN.

[0089] The simulation was repeated with a battery housing made of die-cast aluminum The simulation showed significant damage to the battery/battery modules.

[0090] In the so-called side pole impact test, the battery housing including the battery modules and the control unit together with a frame structure constituting the chassis of the vehicle is pushed perpendicularly and centrally against a pole at 35 km/h. The total weight was 1750 kg. The simulation was repeated with a reduced stiffness of the frame structure (“vehicle chassis”). The battery modules/battery should not be damaged in the pole impact simulation. In the first simulation, an impact energy of 15 960 J acts on the battery housing and in the second simulation an impact energy of 25 309 J.

[0091] The simulation of the pole impact test with the battery housing according to the invention showed that both an impact energy of 15 960 J and an impact energy of 25 309 J were able to be absorbed by the battery housing according to the invention without the battery/battery modules being damaged.

[0092] In the simulation with the above-described comparative housing, severe damage to the battery/battery modules was observed even at an impact energy of 15 960 J.

[0093] At 310.3 kg, the battery housing according to the invention was only slightly heavier than the comparative housing at 291.1 kg.

[0094] The floor made of glass fiber-reinforced polyurethane has a low thermal conductivity of 0.5 W/(m*K) according to DIN EN 993-14 and the battery modules can therefore be operated in an energy-efficient manner in the preferred temperature range.