Button cells and method of producing same

Patent metadata

Field	Value
Publication number	US-11276875-B2
Application number	US-202016810998-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Feb 9, 2009
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A method for producing a button cell includes providing a cell cup, the cell cup having a flat bottom area and a cell cup casing; providing a cell top, the cell top having a flat top area and a cell top casing having a first height; and providing an electrode-separator assembly winding. The cell top casing and the cell cup casing form an overlap area extending in a direction parallel to the axis of the winding and having a second height, the second height being between 20% and 99% of the first height. The method includes applying, in a radial direction perpendicular to the axis of the winding, a pressure on the cell cup casing so as to seal the housing, wherein a portion of the cell top casing that is cylindrical forms at least a part of the overlap area.

First claim

What is claimed is:

1. A method for producing a button cell, the method comprising:
providing a cell cup, the cell cup having a flat bottom area, a cell cup casing, and a bottom edge forming a transition between the flat bottom area and the cell cup casing;
providing a cell top, the cell top having a flat top area, a cell top casing having a first height, and a top edge forming a transition between the flat top area and the cell top casing, wherein at least a portion of the cell top casing is cylindrical;
providing an electrode-separator assembly winding, the electrode-separator assembly winding having a positive electrode and a negative electrode in the form of layers connected to one another by a separator layer and wound up in a spiral shape about an axis, wherein a first of the positive electrode or the negative electrode is formed from a first metallic film or metallic mesh covered with an electrode material;
welding a first output conductor to the first metallic film or mesh;
applying an electrically insulating seal at least to an outer portion of the cell top casing;
inserting the electrode-separator assembly winding into the cell top;
inserting the cell top into the cell cup to form a housing, wherein:
the flat top area is parallel to the flat bottom area,
the axis of the electrode-separator assembly winding is aligned at right angles to both the flat top area and the flat bottom area,
a portion of the first output conductor lies flat between an end face of the electrode-separator assembly winding and one of the flat bottom area or the flat top area, and
the cell top casing and the cell cup casing form an overlap area extending in a direction parallel to the axis of the electrode-separator assembly winding, the overlap area having a second height, the second height being between 20% and 99% of the first height; and

applying, in a radial direction perpendicular to the axis of the electrode-separator assembly winding, a pressure on the cell cup casing so as to seal the housing,
wherein the portion of the cell top casing that is cylindrical forms at least a part of the overlap area.

2. The method of claim 1 , wherein a second of the positive electrode or the negative electrode is formed from a second metallic film or mesh covered with a second electrode material, the method further comprising:
welding a second output conductor to the second metallic film or mesh,
wherein, in the housing, a portion of the second output conductor lies flat between a second end face of the electrode-separator assembly winding and one of the flat bottom area or the flat top area.

3. The method of claim 2 , further comprising:
providing a first insulator and a second insulator,
wherein, in the housing, the first insulator lies between the end face of the electrode-separator assembly and the flat bottom area and the second insulator lies between the end face of the electrode separator assembly and the flat top area.

4. The method of claim 2 , further comprising welding, to the flat bottom area or the flat top area, the portion of the second output conductor that lies flat between the second end face of the electrode-separator assembly winding and the flat bottom area or the flat top area.

5. The method of claim 2 , further comprising providing an insulator between the second end face of the electrode-separator assembly winding and the portion of the second output conductor that lies flat between the second end face of the electrode-separator assembly winding and one of the flat bottom area or the flat top area.

6. The method of claim 5 , wherein the second insulator completely covers the second end face of the electrode-separator assembly winding.

7. The method of claim 1 , wherein the cell cup casing has, at an end opposite the bottom edge, a cut edge, and
wherein the cell cup casing has a third height, the third height being less than the first height such that, when the cell top is inserted into the cell cup to form the housing, it is impossible to bend the cut edge of the cell cup casing over the top edge of the cell top.

8. The method of claim 1 , wherein the cell cup casing has a conical subarea such that an internal diameter of the cell cup casing increases in a direction extending away from the flat bottom area,
wherein the conical subarea of the cell cup casing facilitates the inserting the cell top into the cell cup.

9. The method of claim 8 , wherein the inserting the cell top into the cell cup creates a gap between the cell cup casing and the cell top casing, the gap being adjacent to the conical subarea of the cell cup casing, and
wherein the applying, in the radial direction, the pressure on the cell cup casing causes a reduction in the width of the gap.

10. The method of claim 9 , wherein the cell cup casing has, at an end opposite the bottom edge, a cut edge, and wherein the applying, in the radial direction, the pressure on the cell cup casing so as to cause a reduction in the width of the gap comprises applying the pressure in the radial direction to the cut edge of the cell cup casing.

11. The method of claim 9 , wherein the applying, in the radial direction the pressure on the cell cup casing provides an interference fit between the cell top and the cell cup.

12. The method of claim 8 , wherein the applying the electrically insulating seal at least to the outer portion of the cell top casing includes applying a first portion of the electrically insulating seal to the portion of the cell top casing that is cylindrical and forms at least the part of the overlap area,
wherein the first portion of the electrically insulating seal has an initial thickness prior to being applied to the portion of the cell top casing that is cylindrical and forms at least the part of the overlap area, and
wherein the portion of the cell top casing that is cylindrical and forms at least the part of the overlap area has an external radius,
wherein the cell cup casing has, in the overlap area, a smallest overlap internal radius, and wherein a difference between the external radius and the smallest overlap internal radius is 10% to 90% of the initial thickness.

13. The method of claim 12 , wherein the difference between the external radius and the smallest overlap internal radius is 30% to 70% of the initial thickness.

14. The method of claim 1 , wherein the applying an electrically insulating seal at least to an outer portion of the cell top casing includes applying a first portion of the electrically insulating seal to the portion of the cell top casing that is cylindrical and forms at least the part of the overlap area,
wherein the first portion of the electrically insulating seal has an initial thickness prior to being applied to the portion of the cell top casing that is cylindrical and forms at least the part of the overlap area, and
wherein following the applying, in the radial direction, the pressure on the cell cup casing so as to seal the housing formed by the cell cup and the cell top, the first portion of the electrically insulating seal has a final thickness that is less than the initial thickness thereby providing friction between the cell cup and the cell top so as to hold the cell cup and the cell top together.

15. The method of claim 1 , further comprising drawing a first region of the cell cup casing radially inward.

16. The method of claim 15 , wherein a portion of the first region of the cell cup casing that is drawn radially inward lies outside of the overlap area.

17. The method of claim 1 , wherein simultaneously to the applying, in a radial directio

Assignees

• Varta Microbattery Gmbh

Inventors

• Pytlik Eduard
• LINDNER Jürgen
• Barenthin Ulrich
• Gaugler Winfried

Classifications

• H01M6/10

  with wound or folded electrodes · CPC title

• H01M50/572

  Means for preventing undesired use or discharge · CPC title

• H01M50/463

  Separators, membranes or diaphragms characterised by their shape · CPC title

• H01M10/0587

  of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators · CPC title

• H01M50/46

  Separators, membranes or diaphragms characterised by their combination with electrodes · CPC title