Battery box for electric vehicles
A battery box for electric or hybrid motor vehicles, comprising a peripheral frame which has a generally convex polygonal shape, a bottom part and a top cover; the bottom part being joined to a lower surface of the peripheral frame, said peripheral frame comprising at least an aluminum extruded element, bent in a single direction in at least a position along the extrusion longitudinal direction according an angle wherein said bent aluminum extruded element at the said position presents at least two different inner radii of curvatures.
1. A battery box for electric or hybrid motor vehicles, comprising a peripheral frame which has a generally convex polygonal shape, a bottom part and a top cover; the bottom part being joined to a lower surface of the peripheral frame, said peripheral frame comprising at least an aluminum extruded element, bent in a single direction in at least a position (Π) along the extrusion longitudinal direction according an angle α wherein said bent aluminum extruded element at the said position (Π) presents at least two different inner radii of curvatures (R 1 , R 2 , R 3 ).
2. A battery box according to claim 1 wherein one of said two inner radii of curvatures is more than 2 times greater than the other(s).
3. A battery box according to claim 1 wherein the aluminum extruded element comprises at least three walls W 1 , W 2 , W 3 , the length of the walls W 1 and W 3 being respectively L 1 and L 3 , and at least one hollow chamber and wherein
said wall W 2 is connected with at least said two other walls W 1 and W 3 at their extremities,
at least one of the said two walls W 1 or W 3 is connected at one extremity of said wall W 2 ,
said two walls W 1 and W 3 are substantially perpendicular to said wall W 2 and positioned in a same half-space containing said wall W 2 as a frontier,
a part of said wall W 2 forms a wall of said hollow chamber,
said hollow chamber is located between the two said walls W 1 and W 3 and extends in the direction of said walls W 1 and W 3 over a length L 2 wherein the length L 2 is smaller than L 1 and/or L 3 .
4. A battery box according to claim 3 wherein L 1 is equal to L 3 .
5. A battery box according to claim 3 wherein said wall W 2 is connected with walls W 1 and W 3 at its two extremities, forming substantially a U shape.
6. A battery box according to claim 1 wherein said aluminum extruded element is bent in a single direction according to an angle 90°.
7. A process for manufacturing a battery box with a peripheral frame, comprising at least the following steps,
a) Providing an extruded element in aluminium alloy wherein said extruded element comprises at least three walls W 1 , W 2 , W 3 , the length of the walls W 1 and W 3 being respectively L 1 and L 3 and at least one hollow chamber,
said wall W 2 is connected with at least said two other walls W 1 and W 3 at their extremities,
at least one of the said two walls W 1 or W 3 is connected at one extremity of said wall W 2 ,
said two walls W 1 and W 3 are substantially perpendicular to said wall W 2 and positioned in a same half-space containing said wall W 2 as a frontier,
a part of said wall W 2 forms a wall of said hollow chamber,
said hollow chamber is located between the two said walls W 1 and W 3 and extends in the direction of said walls W 1 and W 3 over a length L 2 wherein the length L 2 is smaller than L 1 and/or L 3 ,
b) Making a notch in each two walls W 1 and W 3 of said extruded element, each notch presents an axis of symmetry (□) and an invariant point, the two invariant points of each notch are located at the same position according to the extrusion direction and the axis (Π) passing by these two invariant points is parallel to wall W 2 ,
c) Bending in one bending direction said extruded element at least once, according an angle α, said bending direction corresponds to said axis (Π) passing by the invariant points of the two notches to form a part of the peripheral frame, said part of peripheral frame presents at least two different inner radii of curvature.
8. A process for manufacturing a battery box according to claim 7 wherein the notch has a sinusoidal shape or a trapezoidal shape or a triangular shape or a rectangular shape or a square shape.
9. A process for manufacturing a battery box according to claim 7 wherein bending is performed by rotary draw bending or press bending.
10. A process for manufacturing a battery box according to claim 7 wherein bending is performed at substantially 90°.
11. A process for manufacturing a battery box according to claim 7 wherein said wall W 2 of aluminum extruded element is connected with said walls W 1 and W 3 at its two extremities, forming substantially a U share.
12. A process for manufacturing a battery box according to claim 7 wherein one extremity of said two walls W 1 or W 3 is not connected at one extremity of said wall W 2 , forming substantially an F shape.
13. A process for manufacturing a battery box according to claim 12 wherein before step c) a part of said wall W 2 is cut off.
14. A process for manufacturing a battery box according to claim 12 wherein said cut part of wall W 2 presents an axis of symmetry which corresponds to the bending axis and said cut part extends in the part of wall W 2 situated outside said walls W 1 and W 3 .