Storage battery grid, method of manufacturing storage battery grid, and storage battery using storage battery grid

1. A storage battery grid comprising:

a frame bone that includes a substantially rectangular shape, the frame bone comprising a first side portion, a second side portion which is opposed to the first side portion, a third side portion which connects one end of the first side portion and one end of the second side portion;

a lug portion that is connected to the first side portion of the frame bone and projects outwardly from the frame bone;

a main bone that extends from the first side portion to the second side portion; and

a plurality of first sub-bones that branch from the main bone and extend obliquely toward the second side portion,

wherein all of the plurality of first sub-bones that reach the third side portion are bent and include a plurality of split bones that are split at a bending point as a boundary at which the first sub-bone is bent,

with respect to each of the plurality of first sub-bones that reach the third side portion, an inclination angle, relative to the main bone, of the split bone remotest from the main bone and connected to the third side portion is greater than an inclination angle of the split bone connected to the main bone, and

all of the inclination angles of all of the split bones remotest from the main bone and connected to the third side portion and the inclination angles of all of the split bones connected to the main bone are 90° or less with respect to the main bone.

2. The storage battery grid according to claim 1 , wherein at each of the plurality of first sub-bones, the inclination angles of the plurality of split bones with respect to the main bone become greater as they are remote from the main bone.

3. The storage battery grid according to claim 1 , wherein at least one of the split bones remotest from the main bone and connected to the third side portion is parallel to the second side portion.

4. The storage battery grid according to claim 1 , wherein the main bone is connected to a connection portion to the lug portion of the first side portion, and

the storage battery grid further comprises a plurality of second sub-bones that are arranged at intervals in a direction in which the first side portion of the frame bone extends, and extend from the first side portion to the second side portion.

5. The storage battery grid according to claim 4 , wherein the each of the plurality of first sub-bones that reach the third side portion is bent at positions at which the first sub-bone intersects any of the plurality of second sub-bones.

6. The storage battery grid according to claim 1 , further comprising:

an extension that extends from the first side portion inward of the frame, and

another sub-bone that extends from the extension,

wherein a width dimension of a base end portion of the extension is greater than that of the another sub-bone.

7. The storage battery according to claim 6 , wherein the extension is formed into a triangular shape having a smaller width dimension toward a tip, and

at least part of the plurality of second sub-bones further extends from a tip portion of the extension.

8. The storage battery according to claim 6 , wherein a first corner portion having an acute cross angle and a second corner portion having an obtuse cross angle are rounded at an intersection at which the first sub-bone and the second sub-bone cross each other, and

a curvature of a rounded surface of the second corner portion is greater than that of a rounded surface of the first corner portion.

9. A storage battery comprising the storage battery grid according to claim 1 .

10. The storage battery according to claim 9 , wherein the storage battery grid is made from a lead alloy.

11. The storage battery according to claim 9 , wherein the storage battery grid is formed by blanking.

12. The storage battery grid according to claim 1 further comprising:

a second sub-bone that extends from the first side portion to the second side portion,

wherein the each of the plurality of first sub-bones that reach the third side portion is bent at a point where the first sub-bone intersects the second sub-bone.

13. The storage battery grid according to claim 1 further comprising:

a second sub-bone that branches from the first side portion and extends toward the second side portion,

wherein the each of the plurality of first sub-bones that reach the third side portion is bent at a point where the first sub-bone intersects the second sub-bone.

14. A method of manufacturing a storage battery grid comprising:

forming a frame bone that includes a substantially rectangular shape, the frame bone comprising a first side portion, a second side portion which is opposed to the first side portion, a third side portion which connects one end of the first side portion and one end of the second side portion;

forming a lug portion that is connected to the first side portion of the frame bone and projects outwardly from the frame bone;

forming a main bone that extends from the first side portion to the second side portion; and

forming a plurality of first sub-bones that branch from the main bone and extend obliquely toward the second side portion,

wherein all of the plurality of first sub-bones that reach the third side portion are bent and include a plurality of split bones that are split at a bending point as a boundary at which the first sub-bone is bent,

with respect to each of the plurality of first sub-bones that reach the third side portion, an inclination angle, relative to the main bone, of the split bone remotest from the main bone and connected to the third side portion is greater than an inclination angle of the split bone connected to the main bone, and

all of the inclination angles of all of the split bones remotest from the main bone and connected to the third side portion and the inclination angles of all of the split bones connected to the main bone are 90° or less with respect to the main bone.

15. The storage battery grid according to claim 1 , wherein the each of the plurality of first sub-bones that reach the third side portion is bent only once.

16. The method of manufacturing a storage battery grid according to claim 14 , further comprising:

forming a second sub-bone that extends from the first side portion to the second side portion,

wherein the each of the plurality of first sub-bones that reach the third side portion is bent at a point where the first sub-bone intersects the second sub-bone.

17. The method of manufacturing a storage battery grid according to claim 16 , further comprising:

forming an extension that extends from the first side portion inward of a frame, and

forming another sub-bone that extends from the extension,

wherein a width dimension of a base end portion of the extension is greater than that of the another sub-bone.

18. The method of manufacturing a storage battery grid according to claim 14 , further comprising:

forming a second sub-bone that branches from the first side portion and extends toward the second side portion,

wherein the each of the plurality of first sub-bones that reach the third side portion is bent at a point where the first sub-bone intersects the second sub-bone.