| 摘要 |
A method for connecting individual lithium ion cells into a battery suited for powering an electric or hybrid vehicle is disclosed. The cell current collectors are electron beam welded to one another and to a connector tab in an substantially oxygen-free atmosphere. The cell current collectors and the connector tab are temporarily secured with a clamp, one portion of which has an opening. The electron beam size may be controlled, by magnetic coils and by the extent of electron scattering by the gas atmosphere, to minimally fill the clamp opening to minimize any irradiation of the clamp. The beam or the workpieces may be displaced, if required, fuse the entire opening area. A similar procedure may be followed to weld a plurality of connector tabs to a busbar. |
| 主权项 |
1. A method of fusion welding a plurality of current collectors, each having an intended joining portion and each being electrically connected to an electrode of a lithium ion battery, to a tab connector with an intended joining portion, in a weld region, the method comprising:
aligning the plurality of current collectors, each ranging in thickness from 10 to 20 micrometers, and the connector tab, to form a workpiece stack with the current collectors being grouped together and positioned on top of the connector tab; positioning the stack in a generally horizontal orientation so that the intended joining portions of all of the current collectors are vertically aligned with the intended joining portion of the tab connector; clamping and compacting the stack between opposing surfaces of only two clamp members, each being of one-piece construction and each with generally flat stack-contacting surfaces; a first clamp member being in contact with the uppermost current collector in the stack and a second clamp member with a continuous, flat supporting surface in contact with and supporting the connector tab at the bottom of the stack, the first clamp member having at least one through opening for exposing the joining portion of the surface of the uppermost current collector in the stack, the stack-contacting surface of the second clamp being free of surface cavities infiltrateable by liquid metal; locating the clamp members and stack in a protective, overlying, substantially oxygen-free atmosphere to avoid oxide formation, and irradiating, from above, through the opening in the first clamp member and the protective overlying atmosphere, at least the exposed, joining portion of the surface of the uppermost current collector in the stack with an electron beam to heat and melt the joining portion of the uppermost current collector of the stack; and then, continuing to irradiate the stack for a time predetermined to progressively melt the joining portions of each of the remaining current collectors and, at least a portion of the joining portion of the tab connector thickness in that portion of the stack located in the first clamp member opening, to form, from the joining portions, a molten pool against the remaining solid tab thickness portion or the second clamp member surface, the molten pool extending through the joining location portions of each of the current collectors and being confined within the first clamp member opening, before ceasing electron irradiation and cooling the stack to thereby fuse together those portions of the current collectors and the tab located in the first clamp member opening to form a low resistance fusion welded electrical interconnection between all the stack members at their respective joining portions. |
