BATTERY CELL HAVING A STRUCTURED ACTIVE MATERIAL

Abstract

The invention relates to a battery cell, in particular a lithium ion battery cell, having a cathode (3) comprising a cathode active material (333) and having an anode (1) comprising an anode active material (111), wherein the cathode active material (333) and/or the anode active material (111) is/are structured in such a way that between contiguous cathode active material regions (333a) and/or between contiguous anode active material regions (111a) there are hollow spaces (4) which spatially separate the contiguous cathode active material regions (333a) and/or the contiguous anode active material regions (111a) from one another and wherein the hollow spaces (4) are at least partly filled with an electrically insulating material (5).

Claims

1. A battery cell, in particular lithium ion battery cell, having a cathode (3) comprising a cathode active material (333) and having an anode (1) comprising an anode active material (111), characterized in that the cathode active material (333) and/or the anode active material (111) is/are structured in such a way that between contiguous cathode active material regions (333a) and/or between contiguous anode active material regions (111a) there are hollow spaces (4) which spatially separate the contiguous cathode active material regions (333a) and/or the contiguous anode active material regions (111a) from one another and in that the hollow spaces (4) are at least partly filled with an electrically insulating material (5).

2. The battery cell as claimed in claim 1, characterized in that the electrically insulating material (5) is a polyethylene terephthalate, a polyimide, a polyether ether ketone or a polypropylene.

3. The battery cell as claimed in either of the preceding claims, characterized in that the contiguous cathode active material regions (333a) and/or the contiguous anode active material regions (111a) have a repeating outline.

4. The battery cell as claimed in claim 3, characterized in that the repeating outline is realized in the form of round, triangular or rectangular, in particular square, anode active material regions (111a) and/or cathode active material regions (333a).

5. The battery cell as claimed in any of the preceding claims, characterized in that the cathode active material regions (333a) and/or the anode active material regions (111a) have been applied to an anode support foil (11) and/or a cathode support foil (33) by means of screen printing.

6. The battery cell as claimed in any of the preceding claims, characterized in that the hollow spaces (4) take up 25% of the area coated with anode active material (111) and/or cathode active material (333).

7. The battery cell as claimed in any of the preceding claims, characterized in that individual anode layers and/or cathode layers of the battery cell are arranged in such a way that the anode active material regions (111a) and/or cathode active material regions (333a) are offset relative to one another.

8. A battery comprising at least one battery cell as claimed in any of claims 1-7.

9. The use of a battery as claimed in claim 8 in an electric vehicle, in a hybrid vehicle or in a plug-in hybrid vehicle.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0024] The figures show:

[0025] FIG. 1 a conventional electrode according to the prior art,

[0026] FIG. 2a a schematic depiction of an electrode of a battery cell according to the invention,

[0027] FIG. 2b the electrode of FIG. 2a in a cross section along the line A-A,

[0028] FIG. 2c a schematic depiction of a first variant of he electrode depicted in FIG. 2a,

[0029] FIG. 2d a schematic depiction of a second variant of the electrode depicted in FIG. 2a,

[0030] FIG. 2e a schematic depiction of a third variant of the electrode depicted in FIG. 2a,

[0031] FIG. 3 a schematic depiction of a cross section through an electrode assembly according to the prior art in the nail penetration test,

[0032] FIG. 4a a schematic depiction of a cross section through an electrode assembly of a battery cell according to the invention in the nail penetration test in a first embodiment, and

[0033] FIG. 4b a schematic depiction of a cross section through an electrode assembly of a battery cell according to the invention in the nail penetration test in a second embodiment.

[0034] FIG. 1 shows an electrode according to the prior art. The electrode is, for example, an anode 1 or a cathode 3. The anode 1 or cathode 3 comprises an anode support foil 11 or cathode support foil 33, which is coated over part of its area with an anode active material 111 or a cathode active material 333. The region of the anode support foil 11 or cathode support foil 33 which does not have any coating serves for electrical contacting of the respective electrode and is, for example, welded to a power outlet lead.

[0035] FIG. 2a shows an electrode of a battery cell according to the invention. In contrast to the conventional electrode as shown in FIG. 1, the anode active material 111 or the cathode active material 333 has not been applied over the area of the anode support foil 11 or the cathode support foil 33 but instead in regions, so that hollow spaces 4 are present between contiguous cathode active material regions 333a and between contiguous anode active material regions 111a. The hollow spaces 4 are filled with an electrically insulating material 5. The electrically insulating material 5 comprises, for example, a polyethylene terephthalate, a polyimide, a polyether ether ketone or a polypropylene.

[0036] In an alternative embodiment which is not shown, the hollow spaces 4 are only partly filled with an electrically insulating material 5. The outline of the cathode active material regions 333a and anode active material regions ilia is square and the square cathode active material regions 333a and anode active material regions 111a are arranged with equal spacings on the cathode support foil 33 or anode support foil 11. As an alternative, the outline of the cathode active material regions 333a or anode active material regions ilia is rectangular.

[0037] FIG. 2b depicts the electrode of FIG. 2a in a cross section along the line A-A.

[0038] FIG. 2c depicts a first variant of the electrode shown in FIG. 2a. In contrast to FIG. 2a, the cathode active material regions 333a of the cathode 3 and the anode active material regions 111a of the anode 1 are not square but instead triangular.

[0039] FIG. 2d depicts a second variant of the electrode shown in FIG. 2a. In contrast to FIG. 2a, the cathode active material regions 333a of the cathode 3 and the anode active material regions 111a of the anode 1 are not square but instead round.

[0040] FIG. 2e depicts a third variant of the electrode shown in FIG. 2a. In contrast to FIG. 2a, the cathode active material regions 333a of the cathode 3 and the anode active material regions 111a of the anode 1 are not square but instead have a free shape. The shape depicted in FIG. 2e represents an example of any arbitrary shape.

[0041] FIG. 3 discloses an electrode assembly 14 according to the prior art. The electrode assembly 14 comprises a cathode support foil 33 which is coated on both sides with a cathode active material 333. A separator 16 has been applied to each of the sides of the layers of the cathode active material 333 which face away from the cathode support foil 33. An anode active material 111 has been applied to each of the sides of the separators 16 which face away from the cathode active material 333. An anode support foil 11 has been applied to each of the sides of the anode active material 111 facing away from the separators 16. In an embodiment which is not shown, the electrode assembly 14 comprises further layers, for example further layers of the anode active material 111 on the anode support foil 11.

[0042] The cathode support foil 33 and the layers of the cathode active material 333 form the cathode 3, and the anode support foils 11 and the layers of the anode active material 111 form the anode 1. In FIG. 3, a cathode 3 is stacked in the specified order on an anode 1 and a further anode 1 is in turn stacked on the cathode 3. This is depicted only by way of example; further anodes 1 and cathodes 3 can be stacked on top of one another or there can be only one anode 1 and only one cathode 3. A separator 16 is in each case installed between an anode 1 and a cathode 3. This serves for spatial and electrical separation of the electrodes 1,3. In FIG. 3, a nail 20 has been pushed through the electrode assembly 14. This represents a critical situation and leads to unwanted reactions as have been described above in the disclosure of the invention.

[0043] FIG. 4a depicts an electrode assembly 14 of a battery cell according to the invention in a first embodiment. In contrast to FIG. 1, the anode active material 111 and the cathode active material 333 have not been applied over the full area of the anode support foil 11 and the cathode support foil 33 but instead only in regions as in FIG. 2, so that hollow spaces 4 are present between contiguous cathode active material regions 333a and between contiguous anode active material regions 111a. The hollow spaces 4 are filled with an electrically insulating material 5. The hollow spaces 4 which have been filled with electrically insulating material 5 in the layers of the anodes 1 and the cathode 3 are located directly above one another in FIG. 4a. Likewise, the cathode active material regions 333a and the anode active material regions 111a are located directly above one another. The nail 20 goes through the electrode assembly 14 in FIG. 4a in such a way that it adjoins superposed cathode active material regions 333a and anode active material regions 111a and also superposed hollow spaces 4 filled with electrically insulating material 5 in the electrodes 1, 3. Thus, not only are cathode active material regions 333a and anode active material regions 111a which are important for the function of the battery cell damaged, but regions which are unimportant for the function of the battery cell, namely the hollow spaces 4 filled with electrically insulating material 5, are also damaged. The advantages and improvements compared to conventional cells resulting therefrom have been described above in the disclosure of the invention.

[0044] FIG. 4b depicts an electrode assembly 14 of a battery cell according to the invention in a second embodiment. In contrast to the first embodiment depicted in FIG. 4a, the hollow spaces 4 filled with electrically insulating material 5 in the layers of the anode 1 and of the cathode 3 are not located above one another but instead are offset. Likewise, the cathode active material regions 333a and the anode active material materials 111a are not located above one another but instead are offset. In FIG. 4b, the electrode active material regions 111a, 333a of every second electrode layer are aligned above one another, so that a regular offset pattern is formed. The nail 20 goes through the electrode assembly 14 in FIG. 4b in such a way that it adjoins both cathode active material regions 333a and anode active material regions 111a and also hollow spaces 4 filled with electrically insulating material 5 in the electrodes 1, 3.

[0045] In an alternative embodiment which is not shown, the offset is not present in every second electrode layer but instead in every nth electrode layer, where n is any number.

[0046] In an alternative embodiment which is not shown, the anode active material regions 111a are offset relative to the cathode active material regions 333a.

[0047] In a further embodiment which is not shown, the anode active material regions 111a and the cathode active material regions 333a do not have the same length, so that an offset thereby results. Furthermore, as an alternative or in addition, the active material regions 111a, 333a of a single electrode layer do not have equal lengths.

[0048] In a further embodiment which is not shown, all electrode layers are arranged randomly, so that the electrode active material regions 111a, 333a overlap randomly.

[0049] In all embodiments, not only are cathode active material regions 333a and anode active material regions 111a which are important for the function of the battery cell damaged, but regions which are unimportant for the function of the battery cell, namely the hollow spaces filled with electrically insulating material 5, are also damaged. The advantages and improvements compared to conventional battery cells which result therefrom have been described above in the disclosure of the invention.