ROLLED ENERGY STORAGE ELEMENTS AND METHOD FOR THE PRODUCTION THEREOF

Abstract

Rolled-up energy storage elements, each including a rolled layer stack of layers which are arranged within a layer plane in an at least partially covering manner. In the layer stack, at least two layers are present which are at least partially electrically conductive, and at least one layer of a non-liquid electrolyte material is present, or at least one region between at least two layers of the rolled layer stack is present which comprises a liquid electrolyte. Either at least one of the layers that is at least partially electrically conductive includes at least partially a magnetic material, or an additional layer that includes at least partially a magnetic material in the layer stack.

Claims

1. Rolled-up energy storage elements, each comprising a rolled layer stack of layers which are arranged within a layer plane in an at least partially covering manner, and in the layer stack at least two layers are present which are at least partially electrically conductive, and at least one layer of a non-liquid electrolyte material is present, or at least one region between at least two layers of the rolled layer stack is present which comprises a liquid electrolyte, wherein either at least one of the layers that are at least partially electrically conductive comprises at least partially a magnetic material, or an additional layer that conductive comprises at least partially a magnetic material is present in the layer stack.

2. The rolled-up energy storage elements according to claim 1 in which the number of the rolled windings in the rolled layer stack is at least 10, advantageously 20 to 400, completely rolled windings.

3. The rolled-up energy storage elements according to claim 1 in which the layer thickness of the entire layer stack is maximally 1 mm.

4. The rolled-up energy storage elements according to claim 1 in which no web material is rolled-in.

5. The rolled-up energy storage elements according to claim 1 in which the layer stack furthermore comprises at least two at least partially electrically conductive layers that are arranged within a layer plane in an at least partially covering manner, between which layers, also within a layer plane, at least one electrically insulating layer is arranged.

6. The rolled-up energy storage elements according to claim 1 in which the topmost layer of the layer stack is composed of an at least partially electrically insulating material.

7. The rolled-up energy storage elements according to claim 1 in which all outer surfaces, except for a part of the electrically conductive layers, are covered by an electrically insulating layer.

8. The rolled-up energy storage elements according to claim 1 in which the topmost layer comprises an electrically conductive material and the layer positioned thereunder comprises an electrically insulating material.

9. The rolled-up energy storage elements according to claim 1 in which the layer stack comprises two electrically conductive layers, between which one layer of a cathode material and one layer of an anode material are arranged, between which in turn one layer of an electrolyte material is arranged, and an electrically insulating layer is arranged on the upper electrically conductive layer, wherein at least one of the electrically conductive layers comprises a magnetic material.

10. The rolled-up energy storage elements according to claim 1 in which the layers or the part of a layer of the magnetic material are composed of Co, Fe, Nd, Ni; or of Co-, Fe-, Nd- or Ni-based alloys; or of alloys of these materials.

11. The rolled-up energy storage elements according to claim 1 in which the layer of the electrolyte material is a solid-state electrolyte material and is advantageously composed of LiPON.

12. The rolled-up energy storage elements according to claim 1 in which the layer of the cathode material comprises at least one metal oxide.

13. The rolled-up energy storage elements according to claim 1 in which at least two layers of electrically conductive material are provided with electrically conductive contact electrodes on the two spiral-shaped faces of the rolled layer stack.

14. A method for the production of rolled energy storage elements, in which method at least one layer stack is applied to a substrate or a sacrificial layer on a substrate in a differentially strained manner, wherein the layer stack comprises at least two layers that are arranged within a layer plane in an at least partially covering manner, and in the layer stack the materials of at least two layers are at least partially electrically conductive, and either an additional layer is present which is composed of a non-liquid electrolyte material, or at least before and/or during and/or after the rolling-up of the layer stack a region is produced that can be filled with a liquid electrolyte, and the material of at least one of the layers that are at least partially electrically conductive is at least partially a magnetic material, or an additional layer of a magnetic material is present, and subsequently the independent rolling-up of the layer stack is induced, and at least intermittently during the rolling-up of the layer stack the layer stack is exposed to an external magnetic field, the field strength of which is at least greater than the field strength of the Earth's magnetic field, and the liquid electrolyte is added into the region before or during or after the rolling-up of the layer stack.

15. The method according to claim 14 in which an external magnetic field is applied in which the magnetic field lines projected onto the not yet rolled-up layer stack are aligned approximately perpendicularly or exactly perpendicularly to the rolling direction of the layer stack.

16. The method according to claim 14 in which at least two or a plurality of the layer stacks with a magnetic material are self-rolled in exactly one rolling direction.

17. The method according to claim 14 in which at least one of the layers of an electrically conductive material is arranged essentially transversely to the rolling-up direction such that it extends beyond the width of the layer stack on one side, and at least a second of the layers of an electrically conductive material is arranged essentially transversely to the rolling-up direction such that it extends beyond the width of the layer stack on the other side.

18. The method according to claim 14 in which at least two or a plurality of the layer stacks with a magnetic material are arranged in a differentially strained manner, wherein at least one layer stack is self-rolled in one direction and at least one layer stack is self-rolled in another direction, and first the layer stack or stacks with the first rolling direction is/are exposed at least intermittently during the independent rolling-up to an external magnetic field, the field strength of which is at least greater than the field strength of the Earth's magnetic field and of which the magnetic field lines projected onto the not yet rolled-up layer stack are aligned approximately perpendicularly or exactly perpendicularly to this first rolling direction of the layer stack, and subsequently the layer stack or stacks with a different rolling direction is/are exposed at least intermittently during the independent rolling-up to an external magnetic field, the field strength of which is at least greater than the field strength of the Earth's magnetic field and of which the magnetic field lines projected onto the not yet rolled-up layer stack are aligned approximately perpendicularly or exactly perpendicularly to this other rolling direction of the layer stack, and this method sequence is then carried out consecutively for each layer stack rolling direction.

19. The method according to claim 14 in which an external magnetic field with flux densities between 1 mT and 1 T and/or with a varying flux density is used.

20. The method according to claim 14 in which the layer stack or stacks is/are exposed to the external magnetic field throughout the entire duration of the rolling-up.

21. The method according to claim 14 in which the rolled energy storage elements are removed from the substrate surface by application of at least one magnetic field.

22. The method according to claim 14 in which rolled energy storage elements are integrated into electric circuits with the aid of a pick-and-place process, wherein the rolled-up energy storage elements are exposed at least intermittently to an external magnetic field during the pick-and-place process.

23. The method according to claim 14 in which two or more layers are arranged within a layer plane such that they only partially cover the layers arranged thereunder and/or thereabove.

24. A method of using the rolled energy storage elements according to claim 1 in electric or electronic circuits.

Description

EXAMPLE

[0070] First, a water-soluble sacrificial layer of germanium oxide is applied to the surface of a silicon substrate. Then, a 1-m thick ferromagnetic layer of nickel is applied as a first electrically conductive layer to the surface of the sacrificial layer, followed by a layer of LiCoO.sub.2 as a cathode with a thickness of 1 m. A solid-state electrolyte layer of UPON is subsequently applied with a thickness of 10 m to the surface of the cathode layer. This is followed by a layer of Si as an anode with a thickness of 1 m. The layer stack is completed with the upper, second electrically conductive layer of nickel with a thickness of 1 m, followed by a 500-nm thick Cr layer that creates a significant expansion strain, and a 100-nm thick electrically insulating layer of Al.sub.2O.sub.3. The two electrically conductive layers serve as electric current collectors for the rolled-up layer stack.

[0071] The layer stack is structured in-plane using photolithographic methods, whereby the layer stack has a width of 1 cm and a length of 20 cm, and the two electrically conductive current-collector layers protrude past the long sides of the layer stack by 200 m. On one of the short sides, a strip of the layer stack is removed by means of reactive ion etching, whereby the sacrificial layer becomes visible again and can be dissolved from this position. The substrate is then placed in water with the layer stack. The sacrificial layer dissolves and, due to the differentially integrated strain and also by applying an external magnetic field with a flux density of 500 mT, the field lines of which point perpendicularly to the rolling direction and layer thickness, the layer stack rolls up on its own in a straightly aligned and compact manner to form a tightly wound microbattery having 400 windings.

[0072] The microbattery, which is located on the substrate, is then lifted off the substrate, connected to electrode material on the two spiral-shaped faces, and electrically insulated on the entire surface that now remains. The microbattery is then transported to its location of use in a packaged state and used as a discrete power-supplying energy storage element in an electric or electronic circuit.