RECHARGEABLE BATTERY

Abstract

A battery, in particular a rechargeable battery, with improved deep discharge stability is provided. The battery comprises at least one positive electrode with a positive current collector and at least one negative electrode with a negative current collector. The negative current collector is made of an electrically conductive non-metallic structural material, in particular structural carbon. Preferably, the battery is a lithium or lithium ion battery.

Claims

1. Battery comprising a) at least one positive electrode with a positive current collector, b) at least one negative electrode with a negative current collector, wherein c) the negative current collector is made of an electrically conductive non-metallic structural material.

2. Battery according to claim 1, wherein the negative current collector comprises a foil or a sheet of an electrically conductive non-metallic structural material.

3. Battery according to claim 1, wherein the electrically conductive non-metallic structural material comprises structural carbon.

4. Battery according to claim 1, wherein the positive current collector is made of an electrically conductive non-metallic structural material, in particular a structural carbon.

5. Battery according to claim 1, wherein the battery is a lithium battery or a lithium ion battery.

6. Battery according to claim 1, wherein the battery has a volume smaller than 30 cm.sup.3.

7. Battery according to claim 1, wherein the battery comprises a) two or more positive electrodes each having a positive current collector, b) two or more negative electrodes each having a negative current collector, and c) at least one contacting fixture having at least one contacting element arranged between adjacent negative current collectors or arranged between adjacent positive current collectors.

8. Use of a battery according to claim 1 in medical, aerospace or military devices.

9. Method for manufacturing a battery according to claim 1, comprising the steps of: a) providing at least one positive electrode with a positive current collector; b) providing at least one negative electrode by coating at least one negative current collector made of an electrically conductive non-metallic structural material with active negative material, c) conventionally assembling the battery.

10. Method according to claim 9, wherein the step of providing at least one positive electrode with a positive current collector comprises the step of coating at least one positive current collector made of an electrically conductive non-metallic structural material with positive active material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The drawings used to explain the embodiments show:

[0062] FIG. 1 a cross section of a battery with electrically conductive non-metallic negative electrode current collector and a metallic positive current collector, and

[0063] FIG. 2 a cross section of a battery with electrically conductive non-metallic negative electrode current collector and electrically conductive non-metallic positive current collector, and

[0064] FIG. 3 a cross section of a battery with electrically conductive non-metallic negative electrode current collector and a contacting fixture having contacting elements.

[0065] In the figures, the same components are given the same reference symbols.

PREFERRED EMBODIMENTS

[0066] FIG. 1 shows an embodiment of a battery 1 comprising a lithium ion rechargeable battery cell. Battery 1 comprises a negative electrode 2. The negative electrode 2 comprises a negative current collector 4 made of an electrically conductive non-metallic structural material. The negative electrode 2 further comprises a negative active material 6, for example carbonaceous material. The negative current collector 4 and the negative active material 6 are electrically connected. The negative current collector 4 is further connected to a contacting fixture 9, which is finally connected to a load or charger 10. Battery 1 further comprises a positive electrode 3. The positive electrode 3 comprises a metallic positive current collector 5. For example, the metallic positive current collector 5 is made of aluminium. The positive electrode 3 further comprises a positive active material 7, as for example LiCoO.sub.2 or LiFePO.sub.4. The battery 1 comprises also a lithium electrolyte (not shown) which can be either in a liquid, a gel or a solid form. Optionally, the battery 1 comprises a separator to keep the positive electrode 2 and the negative electrode 3 spaced from each other. The metallic positive current collector 5 is further connected to a contacting fixture 9, which is finally connected to a load or charger 10. If the load or charger 10 is operated to discharge the battery 1, the ions (not shown) move within the electrolyte in a discharge direction 11. If the load or charger 10 is operated to charge the battery 1, the ions (not shown) move within the electrolyte in a charge direction 12. In this particular embodiment, the negative current collector 4 of the negative electrode 2 is made of a graphite sheet, as for example Laird TGON 9000. However, other graphite sheets, as well as pyrolytic graphite sheets can be used as well.

[0067] FIG. 2 shows another embodiment of a battery 20. In contrast to FIG. 1, the positive electrode 3 comprises a non-metallic positive current collector 8, similar to the negative current collector 4. The non-metallic positive current collector 8 is made of an electrically conductive non-metallic structural material. All other features of the embodiment shown in FIG. 2 are identical with the features shown in FIG. 1 and are not explained again.

[0068] FIG. 3 shows another embodiment of a battery 30. In contrast or in addition to FIGS. 1 and 2, a contacting fixture 90 comprises contacting elements 13 located between the negative current collectors 4 of adjacent negative electrodes 2. The negative current collectors 4 are not coated with negative active material 6 in such areas of the negative current collectors 4 where the contacting elements 13 are located. A plurality of negative electrodes 2 forms a stack of negative electrodes. Accordingly, a plurality of contacting elements 13 forms a stack of contacting elements with negative current collectors 4 in between to form contacting fixture 90.

[0069] Any or all of the features of the embodiments shown in FIGS. 1 and 2 can be combined with any or all of the features of the embodiment shown in FIG. 3.

[0070] In addition or as alternative to the embodiment shown in FIG. 3, in a further embodiment (not shown) a contacting fixture 90 can be used to contact metallic positive current collectors 5 or non-metallic positive current collectors 8 of the positive electrodes. In addition or as alternative to the embodiment shown in FIG. 3, in another further embodiment (not shown) a stack of negative electrodes and/or a stack of positive electrodes can be used in combination with the features shown in FIGS. 1 and/or 2.

[0071] In summary, it is to be noted that the present invention provides a battery with excellent deep discharge stability as well as method for manufacturing said battery using conventional machinery.