Traction battery pack shield and shielding method

1. A battery assembly, comprising:

a traction battery pack having a polymer-based enclosure;

a shield having a floor and a plurality of walls extending transversely away from the floor, the shield provides a cavity that receives a traction battery pack of an electrified vehicle, the cavity is larger than the traction battery pack so that there is a gap between at least some of the plurality of the walls and the traction battery pack within the cavity,

the battery pack supported on the floor of the shield and biased toward a vehicle frame, the walls extending transversely from the floor to the vehicle frame;

a vehicle frame spanning over the cavity from a first one of the plurality of walls to an opposite, second one of the plurality of walls, wherein the shield is electrically grounded to the vehicle frame; and

an isolator of the shield that isolates loads moving from the vehicle frame to the shield, wherein the isolator is a corrugated portion of the shield, and the shield with the corrugated portion is a metal or metal alloy.

2. The battery assembly of claim 1 , further comprising a cover of the shield directly attached to at least one of the plurality of walls and moveable to a position that covers the cavity.

3. The battery assembly of claim 2 , further comprising a living hinge attaching the cover to the at least one of the plurality of walls.

4. The battery assembly of claim 1 , wherein the shield is secured directly to the vehicle frame.

5. The battery assembly of claim 1 , wherein the shield is secured to the vehicle frame through the isolator.

6. The battery assembly of claim 1 , wherein the shield includes an aluminum material, and the shield provides thermal energy and electromagnetic shielding for the battery pack.

7. A battery pack shielding method, comprising:

securing a shield to a vehicle frame to enclose a traction battery pack held within a cavity of the shield; and

pressing a floor of the shield against the battery pack to compress the battery pack during the securing; and

covering the battery pack with a cover of the shield that is separate from the vehicle frame, the cover secured to a wall of the shield using a living hinge.

8. The battery pack shielding method of claim 7 , further comprising grounding the shield to the vehicle frame.

9. The battery pack shielding method of claim 7 , wherein the battery pack includes a polymer-based enclosure, and the shield includes a metal or metal alloy material providing thermal and electromagnetic shielding.

10. The battery pack shielding method of claim 7 , wherein the wall is one of a plurality of walls extending transversely away from the floor, the battery pack held in the cavity such that the battery pack is spaced a distance from the plurality of walls to provide a gap between the plurality of walls and the shield.

11. A battery pack shielding method, comprising:

securing a shield to a vehicle frame to enclose a traction battery pack held within a cavity of the shield;

pressing a floor of the shield against the battery pack to compress the battery pack during the securing; and

isolating loads sent from the vehicle frame to the battery pack using an isolator of the shield, wherein the isolator comprises a corrugated portion of the shield, and the corrugated portion is a metal or metal alloy.

12. The battery pack shielding method of claim 11 , further comprising crimping a portion of the shield to provide the corrugated portion.

13. A battery assembly, comprising:

a shield having a floor and a plurality of walls extending transversely away from the floor, the shield provides a cavity that receives a traction battery pack of an electrified vehicle, the cavity is larger than the traction battery pack so that there is a gap between at least some of the plurality of the walls and the traction battery pack within the cavity; and

a vehicle frame extending from a first one of the plurality of walls to an opposing, second one of the plurality of walls to cover the cavity,

wherein the shield interfaces with the vehicle frame through a flange, and an interface between the vehicle frame and the flange is vertically offset from a seam of the enclosure, the seam where a tray of the enclosure interfaces directly with a cover of the enclosure.