Lithium electrochemical accumulator having a terminal directly connected to the electrochemical assembly and associated production methods

Patent metadata

Field	Value
Publication number	US-2017117575-A1
Application number	US-201515129478-A
Country	US
Kind code	A1
Filing date	Apr 8, 2015
Priority date	Apr 8, 2014
Publication date	Apr 27, 2017
Grant date	—

Abstract

The present invention relates to a lithium-ion electrochemical accumulator comprising an electrode assembly, a casing arranged to sealably contain the electrode assembly, two current output terminals each connected to one or other of the anode(s) and cathode(s) of the assembly, one of the terminals, called the first terminal, passing through a wall of the casing and being electrically insulated therefrom. According to the invention, the first terminal comprises a first conductive part passing through the casing and comprising a portion at least one region of which is welded directly to the bottom.

First claim

1 . A lithium electrochemical accumulator including:
at least one electrochemical cell made up of a least an anode and a cathode on either side of an electrolyte with which a separator is impregnated, the cell(s) defining an electrochemical assembly having an elongated shape along a longitudinal axis with, at one of the lateral ends thereof, uncoated strips of the anode and, at the other of the lateral ends thereof, uncoated strips of the cathode; at least some of the uncoated strips of the anode or of the cathode of the electrochemical assembly being packed together while forming a base; a housing arranged to contain, in a sealed manner, the electrochemical assembly, two current output terminals each connected to either of the anode(s) or of the cathode(s), one of the terminals called the first terminal passing through a wall of the housing and being electrically insulated therefrom, wherein the first terminal includes a first conducting piece passing through the housing and including a portion, at least one area of which is directly welded on the base.

2 . The electrochemical accumulator as claimed in claim 1 , wherein the second terminal is welded to the housing.

3 . The electrochemical accumulator as claimed in claim 1 , wherein
the first terminal includes a female second conducting piece, the first piece ( 21 ) is male, the accumulator includes two electrically insulating joints in the form of washers, each including a bearing portion surface-bearing with pressure against one of the faces of the wall of the housing and a guide portion projecting with respect to the bearing portion, the guide portion bearing with pressure against the rim of the through-hole of the wall, the male piece is press-fitted into the female piece, each of the conducting pieces including a bearing portion surface-bearing with pressure against the bearing portion of the washers, the female piece furthermore surface-bearing with pressure against the guide portions of the washers.

4 . The accumulator as claimed in claim 3 , wherein the male and female pieces are welded together by a weld continuous seam.

5 . The accumulator as claimed in claim 1 , wherein the portion are welded to the base by an area of lesser thickness of the first piece having a thickness e preferably between 0.1 and 0.8 mm, and a width l preferably between 0.3 and 2 mm.

6 . The accumulator as claimed in claim 5 , wherein the area of lesser thickness is an outer peripheral area of the first piece.

7 . The accumulator as claimed in claim 5 , wherein the area of lesser thickness is an annular peripheral recess.

8 . The accumulator as claimed in claim 1 , wherein the portion is welded onto the base by laser transmission.

9 . The accumulator as claimed in claim 1 , wherein the terminals are made of copper or nickel-plated copper.

10 . The accumulator as claimed in claim 1 , wherein the uncoated strips of a same electrode are connected to each other by at least a weld radial to the axis of the assembly.

11 . The accumulator as claimed in claim 1 , wherein the electrochemical assembly is obtained by winding, the first terminal being welded on the winding axis of the electrochemical assembly.

12 . The accumulator as claimed in claims 1 , wherein the electrochemical assembly is obtained by winding, the terminal being welded midway between the winding axis of the electrochemical assembly and the outer periphery of the electrochemical assembly.

13 . The accumulator as claimed in claim 1 wherein the accumulator has a generally cylindrical shape.

14 . The accumulator as claimed in claim 1 , wherein the accumulator has a generally prismatic shape.

15 . The accumulator as claimed in claim 1 , wherein the materials and the dimensions of the various pieces are chosen to allow the flow of a current having an intensity equal to or greater than 250 A.

16 . A method of producing an electrochemical accumulator as claimed in claim 1 , according to which the following steps are carried out:
a. axially packing together, along the axis of the electrochemical assembly, at least some of the uncoated strips of a same electrode of the electrochemical assembly in order to create the base, b. positioning the first conducting piece of the first terminal directly on the base, c. welding the first piece directly to the base.

17 . The method as claimed in claim 16 , further including the following steps:
d. positioning two electrically insulating joints in the form of washers on either side of a hole passing through the wall of the housing, e. positioning the second piece of the first terminal through the holes of the washers and the through-hole of the wall of the housing, f. force-fitting the unit made up of the wall, the second piece and the washers on the first piece, g. crimping the first terminal by surface-bearing on the upper surface of the second piece until this upper surface is aligned with the upper surface of the first piece passing through the housing and the washers are axially and radially compressed, h. producing a weld continuous seam between the first piece and the second piece.

Assignees

• Commissariat Energie Atomique

Inventors

• Dewulf Frédéric
• Chami Marianne

Classifications

• H01M50/566 Primary

  by welding, soldering or brazing · CPC title

• H01M50/548

  on opposite sides of the cell · CPC title

• H01M50/179

  for cells having curved cross-section, e.g. round or elliptic (H01M50/176, H01M50/181 take precedence) · CPC title

• H01M50/176

  for prismatic or rectangular cells (H01M50/181 takes precedence) · CPC title

• H01M50/562

  characterised by the material · CPC title