Double-barrel ball bats

1. A ball bat comprising:

a bat frame having a handle and an inner barrel structure;

two spacer elements positioned on the inner barrel structure, the two spacer elements extending radially outwardly from the inner barrel structure; and

a barrel shell formed with one or more layers of composite laminate material, the barrel shell comprising a main barrel and a tapered section, wherein an inner diameter in the tapered section is equal to an outer diameter of a first one of the spacer elements;

wherein a gap is positioned between the barrel shell and the inner barrel structure and extends between the two spacer elements;

wherein the barrel shell has a first compression value and the inner barrel structure has a second compression value that is higher than the first compression value; and

wherein a layer of elastomeric material is positioned around at least a portion of the inner barrel structure, wherein a thickness of the layer of elastomeric material is less than a width of the gap between the barrel shell and the inner barrel structure.

2. The ball bat of claim 1 , further comprising one or more additional elastomeric materials positioned on the inner barrel structure between the barrel shell and the inner barrel structure.

3. The ball bat of claim 1 wherein at least one of the spacer elements comprises a partial ring or a complete ring around the inner barrel structure.

4. The ball bat of claim 1 wherein at least one of the spacer elements comprises an elastomeric material and is configured to absorb energy from an impact on the barrel shell.

5. The ball bat of claim 1 wherein a first part of the inner barrel structure has a first outer diameter that is greater than a second outer diameter of any other part of the inner barrel structure, and wherein a portion of the gap adjacent to the first part of the inner barrel structure is smaller than other portions of the gap.

6. The ball bat of claim 1 further comprising at least a third spacer element.

7. A ball bat comprising:

a bat frame having a handle and an inner barrel structure;

two spacer elements positioned on the inner barrel structure, the two spacer elements extending radially outwardly from the inner barrel structure;

a barrel shell formed with one or more layers of composite laminate material, the barrel shell comprising a main barrel and a tapered section, wherein an inner diameter in the tapered section is equal to an outer diameter of a first one of the spacer elements and wherein a gap is positioned between the barrel shell and the inner barrel structure, the gap extending between the two spacer elements; and

a layer of elastomeric material around at least a portion of the inner barrel structure, wherein a thickness of the layer of elastomeric material is less than a width of the gap between the barrel shell and the inner barrel structure;

wherein the barrel shell has a first compression value and the inner barrel structure has a second compression value that is different from the first compression value.

8. The ball bat of claim 7 wherein the first compression value is less than the second compression value.

9. The ball bat of claim 7 wherein at least one of the spacer elements is integral with the inner barrel structure.

10. The ball bat of claim 7 wherein at least one of the spacer elements comprises an elastomeric material.

11. The ball bat of claim 7 wherein a first part of the inner barrel structure has a first outer diameter that is greater than a second outer diameter of any other part of the inner barrel structure, and wherein a portion of the gap adjacent to the first part of the inner barrel structure is smaller than other portions of the gap.

12. The ball bat of claim 7 further comprising at least a third spacer element.

13. A ball bat comprising:

a bat frame having a handle and an inner barrel structure, the inner barrel structure comprising a tapered region connected to the handle;

an end knob attached to the handle and at least partially positioned within the handle;

two or more spacer elements integrally formed on the inner barrel structure, the two or more spacer elements extending radially outwardly from the inner barrel structure; and

a barrel shell comprising a main barrel and a tapered section, wherein an inner diameter in the tapered section is equal to an outer diameter of a first one of the spacer elements;

wherein a gap is positioned between the barrel shell and the inner barrel structure; and

wherein a layer of elastomeric material is positioned in the gap around at least a portion of the inner barrel structure, wherein a thickness of the layer of elastomeric material is less than a width of the gap between the barrel shell and the inner barrel structure.

14. The ball bat of claim 13 wherein the barrel shell has a first compression value and the inner barrel structure has a second compression value that is different from the first compression value.

15. The ball bat of claim 13 wherein the inner barrel structure comprises an outer diameter that varies along its length, wherein the gap between the barrel shell and the inner barrel structure has a first width in a first region of the ball bat, and a second width different from the first width in a second region of the ball bat.

16. The ball bat of claim 15 wherein the first region of the ball bat includes the center of percussion of the ball bat.

17. The ball bat of claim 13 further comprising a collar positioned at an interface between the handle and the barrel shell.