Lithium cell having an improved cathode structure and production method for it

Patent metadata

Field	Value
Publication number	US-9276255-B2
Application number	US-201013514281-A
Country	US
Kind code	B2
Filing date	Nov 8, 2010
Priority date	Dec 23, 2009
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A lithium cell is described having a cathode structure made of a base material which conducts electrons and Li ions. The cathode structure includes a continuous substrate, which provides a continuous base area, starting from which a plurality of crosspieces extends. The crosspieces provide crosspiece surfaces, starting from which carrier structures extend. The carrier structures provide carrier surfaces on which active material is distributed. In addition, an accumulator is also described in which a plurality of lithium cells is stacked. A method for producing a lithium cell is also described.

First claim

What is claimed is:

1. A lithium cell, comprising:
a cathode structure made of a freeze cast base material which conducts electrons and Li ions, the cathode structure including a continuous substrate, which provides a base area, starting from which extends a plurality of crosspieces which provide crosspiece surfaces, starting from which carrier structures extend, which provide carrier surfaces on which active material is distributed.

2. The lithium cell as recited in claim 1 , wherein the base area, the crosspieces and the carrier structures are directly connected to one another in continuous material fashion and the carrier structures of adjacent crosspieces are arranged opposite to each other, but are not connected directly to each other, and the substrate includes an electrical contact which provides a cathode connection of the lithium cell.

3. The lithium cell as recited in claim 1 , wherein the substrate is developed together with the crosspieces using freeze casting of the base material and the carrier structures are provided by one of nanostructures or nanowires deposited on the crosspiece surfaces, which are developed of the base material.

4. The lithium cell as recited in claim 1 , further comprising:
a solid electrolyte structure made of an electrically insulating, Li ion conducting material, on which the continuous substrate is situated, wherein a side of the substrate opposite the base area is situated directly on the solid electrolyte structure; and
an anode structure having a lithium layer, on which the solid electrolyte structure is directly situated, the solid electrolyte structure being directly situated on a front side and a rear side of the anode structure, the crosspieces extending away from the substrate on both sides of the anode structure.

5. The lithium cell as recited in claim 1 , wherein the base material has an electrode potential with respect to lithium of one of at most 2.9 V or at most 2 V, and includes one of Li—Ti oxide, Li 4−x Mg x Ti 5 O 12 , where 0≦x≦2 or 0≦x≦1, Li 4−x Mg x Ti 5−y (Nb, Ta) y O 12 , where 0≦x≦2 or 0≦x≦1 and 0≦y≦0.1 or 0≦y≦0.05, or Li 2−x Mg x Ti 3−y (Nb, Ta) y O 7 where 0 ≦x≦1 or 0<x<0.5 and 0<y<0.03, and wherein the active material includes at least one of sulfur, sulfur particles, catalyst material arranged to support Li—O reactions, α-MnO 2 or nanocrystalline α-MnO.

6. A lithium accumulator, comprising:
a plurality of lithium cells, each of the lithium cells including a cathode structure made of a freeze cast base material which conducts electrons and Li ions, the cathode structure including a continuous substrate, which provides a base area, starting from which extends a plurality of crosspieces which provide crosspiece surfaces, starting from which carrier structures extend, which provide carrier surfaces on which active material is distributed; and
a mounting support in which the plurality of lithium cells are situated in the form of a stack, the mounting support also including electrical contacts by which the lithium cells are electrically connected to one another, the electrical contacts including plug contacts.

7. A method for producing a lithium cell, comprising:
providing a cathode structure by freeze casting a base material which conducts electrons and Li ions, wherein a continuous substrate which provides a continuous base area and a plurality of crosspieces which extend from the base area, are produced using the same freeze casting step;
providing carrier structures after the substrate and the plurality of crosspieces have been produced, the carrier structures extending starting from the crosspieces, by depositing the base material in the form of one of microstructures or nanostructures; and
applying active material in a distributed manner onto carrier surfaces, which are provided by the carrier structures produced.

8. The method as recited in claim 7 , further comprising:
providing a solid electrolyte structure made of an electrically insulating, Li ion conducting material, wherein the cathode structure is applied directly onto the solid electrolyte structure by freeze casting the base material onto the solid electrolyte structure which is used in the step of the freeze casting as a casting substrate.

9. The method as recited in claim 8 , further comprising:
providing an anode structure, and situating the anode structure on one side of the solid electrolyte layer which is opposite to a side of the cathode structure on which the cathode structure is applied, wherein the anode structure is provided by one of: providing a lithium layer which is embodied in two sublayers between which an electrode layer is situated, the two sublayers being connected to the intermediate electrode layer, by providing a metal foam layer which is interspersed with lithium; or by developing an interspace between two solid electrolyte structures situated towards each other and inserting lithium into the interspace before the cathode structures are applied onto the respective solid electrolyte structures, the inserting of lithium into the interspace being carried out by one of electrochemical pumping of lithium into the interspace or casting the lithium into the interspace.

10. A method for producing a lithium accumulator, comprising:
producing a lithium cell including providing a cathode structure by freeze casting a base material which conducts electrons and Li ions, wherein a continuous substrate which provides a continuous base area and a plurality of crosspieces which extend from the base area, are produced using the same freeze casting step, providing carrier structures after the substrate and the plurality of crosspieces have been produced, the carrier structures extending starting from the crosspieces, by depositing the base material in the form of one of microstructures or nanostructures, and applying active material in a distributed manner onto carrier surfaces, which are provided by the carrier structures produced, situating an electrical contact, which forms a cathode electrode of the lithium cell, in electrical connection to the substrate, at a lateral edge of the substrate, and situating an additional electrical contact, which forms an anode electrode of the lithium cell, on the lithium cell, at an additional lateral edge of the substrate; and
situating a plurality of lithium cells in the form of a stack in a mounting support, in which electrical contacts are provided, by plugging the lithium cells into the electrical contacts of the mounting support, the cathode electrode and the anode electrode becoming electrically connected to the electrical contacts of the mounting support.

Assignees

• Glanz Leonore
• Eisele Ulrich
• Bosch Gmbh Robert

Inventors

• Glanz Leonore
• Eisele Ulrich

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title