Electric power storage device
An electric power storage device includes at least one electric power storage cell having a first end provided with a first electrode, and a second end provided with a second electrode; a first electrode bus bar that is disposed on a side of the first end and is connected to the first electrode; and a second electrode bus bar that is disposed on a side of the second end and is connected to the second electrode. The first electrode bus bar is provided with a connection line connected to the first electrode. The first electrode bus bar and the second electrode bus bar are joined to each other by ultrasonic joining. A joint portion between the first electrode bus bar and the second electrode bus bar is disposed at a position that is closer to the second end than to the first end.
1. An electric power storage device comprising:
at least one electric power storage cell having a first end provided with a first electrode, and a second end provided with a second electrode;
a first electrode bus bar that is disposed on a side of the first end of the at least one electric power storage cell and is connected to the first electrode of the at least one electric power storage cell; and
a second electrode bus bar that is disposed on a side of the second end of the at least one electric power storage cell and is connected to the second electrode of the at least one electric power storage cell, wherein
the first electrode bus bar is provided with a connection line that is directly connected to the first electrode,
the first electrode bus bar and the second electrode bus bar are joined to each other by ultrasonic joining, and
a joint portion between the first electrode bus bar and the second electrode bus bar is disposed at a position that is closer to the second end of the at least one electric power storage cell than to the first end of the at least one electric power storage cell.
2. The electric power storage device according to claim 1 , wherein a thickness of the first electrode bus bar is smaller than a thickness of the second electrode bus bar.
3. The electric power storage device according to claim 1 , wherein:
the first electrode bus bar includes
a body portion that is disposed on the side of the first end of the at least one electric power storage cell, and
an extending portion that extends from the body portion toward the second electrode bus bar and is joined to the second electrode bus bar by the ultrasonic joining; and
the joint portion between the first electrode bus bar and the second electrode bus bar is formed by applying a vibration in a direction that intersects with an extending direction of the extending portion.
4. The electric power storage device according to claim 1 , wherein:
the first electrode bus bar includes
a body portion that is disposed on the side of the first end of the at least one electric power storage cell, and
an extending portion that extends from the body portion toward the second electrode bus bar and is joined to the second electrode bus bar by the ultrasonic joining; and
the joint portion is formed at an end of the extending portion.
5. The electric power storage device according to claim 1 , wherein:
the first electrode bus bar includes
a body portion that is disposed on the side of the first end of the at least one electric power storage cell, and
an extending portion that extends from the body portion toward the second electrode bus bar and is joined to the second electrode bus bar by the ultrasonic joining;
in the body portion, a hole is provided at a position that faces the first end of the at least one electric power storage cell;
the connection line is disposed in the hole;
the connection line includes a base portion that is connected to an inner peripheral edge of the hole; and
in the base portion, the connection line extends in a direction toward the extending portion.
6. The electric power storage device according to claim 1 , wherein the first end of the at least one electric power storage cell is opposite the second end of the at least one electric power storage cell.
7. The electric power storage device according to claim 1 , wherein:
the first electrode has a first polarity, and
the second electrode has an opposite second polarity.
8. The electric power storage device according to claim 1 , wherein:
the first electrode bus bar is directly connected to the first electrode of the at least one electric power storage cell; and
the second electrode bus bar is directly connected to the second electrode of the at least one electric power storage cell.
9. An electric power storage device comprising:
at least one electric power storage cell having a first end provided with a first electrode, and a second end provided with a second electrode;
a first electrode bus bar that is disposed on a side of the first end of the at least one electric power storage cell and is connected to the first electrode of the at least one electric power storage cell; and
a second electrode bus bar that is disposed on a side of the second end of the at least one electric power storage cell and is connected to the second electrode of the at least one electric power storage cell, wherein
the first electrode bus bar is provided with a connection line that is directly connected to the first electrode,
the first electrode bus bar and the second electrode bus bar are each configured to be joined to each other by an ultrasonic joining forming a joint portion,
wherein the joint portion between the first electrode bus bar and the second electrode bus bar is disposed at a position that is closer to the second end of the at least one electric power storage cell than to the first end of the at least one electric power storage cell.
10. The electric power storage device according to claim 9 , wherein a thickness of the first electrode bus bar is smaller than a thickness of the second electrode bus bar.
11. The electric power storage device according to claim 9 , wherein:
the first electrode bus bar includes
a body portion that is disposed on the side of the first end of the at least one electric power storage cell, and
an extending portion that extends from the body portion toward the second electrode bus bar and is joined to the second electrode bus bar by the ultrasonic joining; and
the joint portion between the first electrode bus bar and the second electrode bus bar is formed by applying a vibration in a direction that intersects with an extending direction of the extending portion.
12. The electric power storage device according to claim 9 , wherein:
the first electrode bus bar includes
a body portion that is disposed on the side of the first end of the at least one electric power storage cell, and
an extending portion that extends from the body portion toward the second electrode bus bar and is joined to the second electrode bus bar by the ultrasonic joining; and
the joint portion is formed at an end of the extending portion.
13. The electric power storage device according to claim 9 , wherein:
the first electrode bus bar includes
a body portion that is disposed on the side of the first end of the at least one electric power storage cell, and
an extending portion that extends from the body portion toward the second electrode bus bar and is joined to the second electrode bus bar by the ultrasonic joining;
in the body portion, a hole is provided at a position that faces the first end of the at least one electric power storage cell;
the connection line is disposed in the hole;
the connection line includes a base portion that is connected to an inner peripheral edge of the hole; and
in the base portion, the connection line extends in a direction toward the extending portion.
14. The electric power storage device according to claim 9 , wherein the first end of the at least one electric power storage cell is opposite the second end of the at least one electric power storage cell.
15. The electric power storage device according to claim 9 , wherein:
the first electrode has a first polarity, and
the second electrode has an opposite second polarity.
16. The electric power storage device according to claim 9 , wherein:
the first electrode bus bar is directly connected to the first electrode of the at least one electric power storage cell; and
the second electrode bus bar is directly connected to the second electrode of the at least one electric power storage cell.