Soldering method and soldering structure

1. A soldering method for soldering a tip end of an electric wire to a soldering portion of a planar metallic terminal having a thickness, the method comprising:

a damming structure forming step forming a damming structure at a periphery of the soldering portion to dam a solder which is to be supplied in a molten state together with a flux to the soldering portion to keep the solder at the soldering portion, wherein the damming structure is formed as a receptacle portion having a flat bottom surface, wherein a depth of the damming structure is smaller than the thickness of the planar metallic terminal;

an electric wire setting step setting the tip end of the electric wire at the soldering portion ready for soldering; and

a solder supplying step supplying the solder in the molten state together with the flux to the soldering portion to perform the soldering.

2. The method according to claim 1 , wherein the damming structure forming step includes creating the damming structure, by pressing the metallic terminal, wherein the pressing causes the soldering portion to be recessed in comparison with the periphery or a circumferential edge of the soldering portion to be elevated in a bank shape.

3. The method according to claim 2 , wherein the damming structure forming step includes forming, as the damming structure, a structure in which the soldering portion is surrounded by a wall that is higher than the soldering portion.

4. The method according to claim 1 , wherein the damming structure forming step includes disposing a ring-shaped wall jig surrounding the soldering portion as the damming structure, wherein the wall jig has a smaller thickness than the thickness of the metallic terminal.

5. A soldering structure for soldering a tip end of an electric wire to a soldering portion of a planar metallic terminal having a thickness, comprising:

a solder to be supplied in a molten state together with a flux to the soldering portion; and

a damming structure formed at a periphery of the soldering portion and configured to dam the solder supplied in the molten state together with the flux to the soldering portion to keep the solder at the soldering portion, wherein the damming structure is formed as a receptacle portion having a flat bottom surface, wherein a depth of the damming structure is smaller than the thickness of the metallic terminal.

6. The soldering structure according to claim 5 , wherein the damming structure is a structure in which the soldering portion is surrounded by a wall that is higher than the soldering portion, wherein the wall is configured as an inner circumferential surface of a recess which is formed by recessing the soldering portion in comparison with the periphery, or as an inner circumferential surface of a bank-shaped elevation which is formed by elevating a circumferential edge of the soldering portion, or as an inner circumferential surface of a ring-shaped wall jig with a smaller thickness than the metallic terminal which is disposed surrounding the soldering portion.

7. The soldering structure according to claim 5 , wherein the metallic terminal includes:

a terminal main body including the soldering portion;

a narrow portion extending in an extending direction from the terminal main body and having an area of a cross-section orthogonal to the extending direction smaller than an area of a cross-section of the terminal main body orthogonal to the extending direction; and

a to-be-held portion further extending from the narrow portion and configured to be held by a designated holding structure.

8. The soldering structure according to claim 6 , wherein the metallic terminal includes:

a terminal main body including the soldering portion;

a narrow portion extending in an extending direction from the terminal main body and having an area of a cross-section orthogonal to the extending direction smaller than an area of a cross-section of the terminal main body orthogonal to the extending direction; and

a to-be-held portion further extending from the narrow portion and configured to be held by a designated holding structure.

9. The soldering structure according to claim 7 , wherein the narrow portion is a constricted portion extending in a planar manner from the terminal main body, and wherein a dimension of the constricted portion in a width direction of the constricted portion is smaller than a dimension of the terminal main body in the width direction.

10. The soldering structure according to claim 8 , wherein the narrow portion is a constricted portion extending in a planar manner from the terminal main body, and wherein a dimension of the constricted portion in a width direction of the constricted portion is smaller than a dimension of the terminal main body in the width direction.

11. A soldering method for soldering a tip end of an electric wire to a soldering portion of a stainless metallic terminal covered with an oxide film, the method comprising:

a damming structure forming step forming a damming structure at a periphery of the soldering portion to dam a flux and a solder which is supplied in a molten state together with the flux to the soldering portion to keep the solder and the flux at the soldering portion;

an electric wire setting step setting the tip end of the electric wire at the soldering portion ready for soldering; and

a solder supplying step supplying the solder in the molten state together with the flux to the soldering portion so that the oxide film at the soldering portion is removed by the flux kept in the soldering portion to perform the soldering.