BATTERY HOUSING

Abstract

The present invention relates to a battery housing for an electrically powered vehicle, in particular a motor vehicle, comprising a battery accommodation space made of a first flat steel product and a housing frame made of a second flat steel product, where the two flat steel products differ in terms of at least one of the properties yield strength (R.sub.p0.2), tensile strength (R.sub.M) or elongation (A.sub.50).

Claims

1. A battery housing for an electrically powered vehicle, in particular a motor vehicle, comprising: a battery accommodation space made of a first flat steel product, and a housing frame made of a second flat steel product, where the two flat steel products differ in terms of at least one of the properties yield strength (R.sub.p0.2), tensile strength (R.sub.M) or elongation (A.sub.50).

2. The battery housing as claimed in claim 1, wherein the first flat steel product has at least one of a yield strength of at least 650 MPa, a tensile strength of at least 1250 MPa and an elongation of at least 18% and the second flat steel product has at least one of a yield strength of at least 1000 MPa, a tensile strength of at least 1400 MPa and an elongation of at least 12%.

3. The battery housing as claimed in claim 2, wherein both flat steel products consist of a steel containing, in addition to iron and unavoidable impurities, (in % by weight) C: from 0.1 to 0.35, Si: from 0.5 to 1.8, Mn: from 1.4 to 3.2, Al: up to 1.0, P: up to 0.015, S: up to 0.0025, N: up to 0.0075, and has a microstructure comprising (in % by area) less than 30% of ferrite, less than 10% of bainite, 5-70% of unannealed martensite, 5-30% of residual austenite and 25-80% of annealed martensite, where at least 99% of the iron carbides present in the annealed martensite have a size of less than 500 nm.

4. The battery housing as claimed in claim 1, wherein the battery accommodation space is configured in the form of a trough having a circumferential flange.

5. The battery housing as claimed in claim 4, wherein the trough is made in one piece and has at least one of a radius R.sub.u in the range 5-15 mm and a radius R.sub.o in the range 4-12 mm and a drawing angle in the range 6-8.

6. The battery housing as claimed in claim 4, wherein the trough is made up of at least four frame profiles and a bottom plate.

7. The battery housing as claimed in claim 6 which further comprises an underride guard plate made of the first or second flat steel product.

8. The battery housing as claimed in claim 7, wherein the battery accommodation space has at least one of longitudinal and transverse carriers which are arranged at least one of inside and outside and are made of the second flat steel product.

9. The battery housing as claimed in claim 8, further comprising a lid.

10. The battery housing as claimed in any of claims 1 to claim 9, wherein the housing frame is made up of at least 4 profile elements.

11. The battery housing as claimed in claim 10, wherein the profile elements have reinforcing elements arranged inside.

12. An electrically powered vehicle, in particular motor vehicle, comprising a battery housing as claimed in claim 1.

13. The battery housing as claimed in claim 1, further comprising at least one element selected from the group consisting of Mo, V, Ti and/or Nb, B and Cr in the following contents: Cr: from 0.1 to 0.5, Mo: from 0.05 to 0.25, V: from 0.05 to 0.15, B: from 0.0005 to 0.005, Ti and/or Nb: from 0.005 to 0.135.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will be illustrated below with the aid of drawings. The individual drawings show:

[0034] FIG. 1 a side view of a battery housing as per a first embodiment of the invention,

[0035] FIG. 2 a plan view of the battery housing as per the first embodiment of the invention,

[0036] FIG. 3 a section of a battery accommodation space as per the first embodiment of the invention, and

[0037] FIG. 4 a sectional view of a battery housing as per a second embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0038] FIG. 1 shows a sectional view of a battery housing 10 as per a first embodiment of the present invention. The battery housing 10, which is intended for an electrically powered vehicle (not shown), in particular an electrically powered motor vehicle (E-car), has a battery accommodation space 11 in the form of a trough 12 which is made in one piece. The trough 12 has a circumferential flange 13 via which the trough is joined to a housing frame 20. The housing frame 20 runs along the periphery of the battery housing 10 and has a pentagonal cross section. The battery housing 10 can be joined to the body of the vehicle (not shown) by means of the housing frame 20. For this purpose, the housing frame 20 has a plurality of openings 21 via which it can be screwed to the body. Furthermore, the battery housing has a lid 14 by means of which the trough 12 can be closed. The lid 12 likewise has a circumferential flange 15. The trough 12 can be joined by means of screws to the lid 14 at the housing frame via corresponding openings 16 in the respective flange 13, 15 and in the housing frame 20. Furthermore, the battery housing 10 has an underride guard plate 17 which is arranged under the trough 12 and is fastened detachably, for example by means of screws, to the housing frame 20 via a flange 19. The underride guard plate 17 protects the battery cells 30 from impact stresses impinging from below. Within and outside, i.e. between trough 12 and underride guard plate 17, the battery accommodation space 11 there are longitudinal and transverse carriers 18 which give the battery housing 10 additional stiffness. The longitudinal and transverse carriers 18 can have a profile-like geometry with a preferably hat-shaped or rectangular cross section. It can also be advantageous to provide flanges at the connection to the trough.

[0039] FIG. 2 shows a plan view of the battery housing 10 from which it is possible to see the structure of the housing frame 20 in more detail. The housing frame 20 consists of four individual profile elements 22 which are butt-welded to one another at the respective corners. Furthermore, the housing frame 20 has reinforcing elements 23 which are arranged inside and can be configured as bulkhead plates, hat profiles or meander-shaped profiles arranged inside.

[0040] FIG. 3 shows a section of the battery accommodation space 11 with a deformation region 31 formed by the spacing between the battery cell 30 and the outer wall of the trough 12. The radius R.sub.u, i.e. the radius between the bottom plate of the trough 12 and the outer wall, is preferably in the range 5-15 mm, and the radius R.sub.o, i.e. the radius between the outer wall and the flange 15, is preferably in the range 4-12 mm. The outer wall of the trough 12 preferably has a drawing angle in the range 2-6.

[0041] For the purposes of the present invention, the radius Ru is the radius between a bottom plate and a side wall, and the radius R.sub.o is the radius between the side wall and the flange of the battery accommodation space.

[0042] FIG. 4 shows a sectional view of a battery housing as per a second embodiment. In contrast to the embodiment of FIGS. 1 to 3, the battery accommodation space 11 is made up of four frame profiles 40 and a bottom plate 41. This mode of construction offers better utilization of the installation space since the corners have only a very small radius, if any.

[0043] The lid has little function in a crash and can also be made of a readily formable deep-drawing steel or a steel-polymer sandwich material. Aluminum, steel-polymer sandwich material or polymer are also conceivable.

LIST OF REFERENCE NUMERALS

[0044] 10 Battery housing [0045] 11 Battery accommodation space [0046] 12 Trough [0047] 13 Flange [0048] 14 Lid [0049] 15 Flange [0050] 16 Openings [0051] 17 Underride guard plate [0052] 18 Longitudinal and transverse carriers [0053] 19 Flange [0054] 20 Housing frame [0055] 21 Openings [0056] 22 Profile element [0057] 23 Reinforcing elements [0058] 30 Battery cells [0059] 31 Deformation region [0060] 40 Frame profile [0061] 41 Bottom plate