ELECTROCHEMICAL ACCUMULATOR, WITH PLANAR ARCHITECTURE OBTAINED IN PART BY PRINTING

Abstract

A metal-ion accumulator, including a metal element of flat surface forming a current collector of an electrode of one polarity; an insulating layer, deposited on the metal element while defining an interlocking pattern; a layer forming a current collector of an electrode of opposite polarity to the one having the current collector formed by the metal element, the collector layer being deposited on the interlocking pattern of the insulating layer; an electrode layer, deposited on the metal element according to a pattern at least partly interlocked in the interlocking pattern; an electrode layer of opposite polarity to the one deposited on the metal element, the layer of opposite polarity being deposited on the collector layer according to the interlocking pattern; a layer of electrolyte deposited at least in the spaces between the two layers of active materials of opposite polarity.

Claims

1. A metal-ion electrochemical accumulator, comprising: a metal element of flat surface forming a current collector of an electrode of one polarity; a layer of electrically insulating material, deposited on the metal element, defining an interlocking pattern; a layer forming a current collector of an electrode of opposite polarity to the one having the current collector formed by the metal element, the collector layer being deposited on the interlocking pattern of the insulating layer; a layer of electrode active material, deposited on the metal element according to a pattern at least partly interlocked in the interlocking pattern; a layer of electrode active material of opposite polarity to the one deposited on the metal element, the layer of opposite polarity being deposited on the collector layer according to the interlocking pattern; a layer of electrolyte deposited at least in the spaces between the two layers of active materials of mutually opposite polarity.

2. The accumulator according to claim 1, the metal element being a metal substrate formed by at least one part of an object to be electrically powered by the accumulator.

3. The accumulator according to claim 1, additionally comprising a substrate made of electronically insulating material, the metal element being a metal foil applied against the substrate.

4. The accumulator according to claim 3, the electronically insulating substrate being a polymer substrate chosen from polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyamide (PA), polyimide (PI), polyether ether ketone (PEEK) or being a metal substrate covered with an electronically insulating layer or being a substrate made of an electrically insulating oxide.

5. The accumulator according to claim 3, the foil applied against the substrate being an aluminum foil.

6. The accumulator according to claim 1, the interlocking and interlocked patterns forming an interdigitated pattern or a spirally wound pattern.

7. The accumulator according to claim 1, the material of the electrically insulating layer being chosen from a polymer, a ceramic, an electrically insulating oxide, and an organic-inorganic composite material.

8. The accumulator according to claim 7, the polymer being chosen from polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP).

9. The accumulator according to claim 7, the insulating oxide being alumina or silica (SiO2).

10. The accumulator according to claim 1, the current collector formed by the metal element being the collector of positive polarity.

11. Accumulator The accumulator according to claim 1, additionally comprising a package that encapsulates all of the elements of the accumulator while leaving free one end of the metal element and one end of the current collector layer, which are intended to provide the electrical connections to the outside of the accumulator.

12. A li-ion accumulator according to claim 3, comprising: a flexible polymer substrate; an aluminum foil, stamped on the substrate; a polymer layer defining the interlocking pattern; a copper or carbon layer deposited on the polymer layer according to the interlocking pattern; a layer of lithium insertion material of positive polarity, deposited on the aluminum foil according to the pattern at least partly interlocked in the interlocking pattern; a layer of lithium insertion material of negative polarity, deposited on the copper or carbon layer according to the interlocking pattern; a layer of electrolyte deposited at least in the spaces between layers of lithium insertion materials of positive and negative polarity.

13. A process for producing a metal-ion accumulator, comprising the following steps: a/ providing a metal element that forms a current collector of an electrode of one polarity; b/ depositing, on the metal element, an electrically insulating layer according to an interlocking pattern; c/ depositing, on the electrically insulating layer, a layer forming a current collector of an electrode of opposite polarity to the one having the current collector formed by the metal element, the current collector layer being deposited on the interlocking pattern of the electrically insulating layer; d/ depositing, on the metal element, a layer of electrode active material according to a pattern at least partly interlocked in the interlocking pattern; e/ depositing, on the current collector layer, a layer of electrode active material of opposite polarity to the one deposited on the metal element, according to the interlocking pattern; f/ depositing an electrolyte layer at least in the spaces separating the two layers of active material of mutually opposite polarity.

14. The process according to claim 13, step a/ being carried out by stamping a metal foil on an electronically insulating substrate.

15. The process according to claim 13, the deposition steps b/ to f/ being carried out by a printing technique.

16. A portable electronic device comprising: a casing, and the accumulator according to claim 1 for electrically powering the portable electronic device, wherein the accumulator is integrated into said casing.

Description

DETAILED DESCRIPTION

[0119] Other features and advantages will become more clearly apparent on reading the detailed description, which is given by way of illustration and with reference to the following figures, in which:

[0120] FIG. 1 is a schematic exploded perspective view showing the various elements of a lithium-ion accumulator;

[0121] FIG. 2 is a photographic perspective view showing a lithium-ion accumulator with its flexible package according to the prior art;

[0122] FIG. 3 is a perspective view showing the outside of a lithium-ion accumulator with its flexible package according to the prior art, with the sealing bands necessary for sealing the flexible package and a welding band necessary for welding the current collectors;

[0123] FIG. 4 is a schematic front view of an Li-ion accumulator produced by printing according to patent application FR3007207 A1;

[0124] FIG. 5 is a cross-sectional view of FIG. 4;

[0125] FIGS. 6A to 6C are front views and illustrate the main steps of producing an accumulator according to FIGS. 4 and 5;

[0126] FIGS. 7A to 7E are front views and illustrate the main steps of producing an example of an accumulator according to the invention;

[0127] FIG. 8 is a schematic front view showing another example of an accumulator according to the invention.

[0128] For the sake of clarity, the same references denoting the same elements of an accumulator according to the prior art and of an accumulator according to the invention are used for all the FIGS. 1 to 8.

[0129] It is specified that the various elements according to the invention are represented solely for the sake of clarity and that they are not to scale. FIGS. 1 to 6C have already been commented on in the preamble. They will not therefore be described in detail below.

[0130] The invention is described below with reference to an exemplary embodiment of an Li-ion accumulator having an interdigitated pattern.

[0131] The various steps of producing such an accumulator are described with reference to FIGS. 7A to 7E.

[0132] Step a/: firstly an electronically insulating substrate 7 is put in place. It is advantageously a polymer substrate chosen from polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyamide (PA), polyimide (PI) and polyether ether ketone (PEEK).

[0133] A metal foil 4 made of aluminum is stamped, by deposition if necessary with adhesive bonding, on the substrate 7, forming the cathode current collector (FIG. 7A). As illustrated, the stamped aluminum foil 4 has one end intended to form the positive electrical connection.

[0134] Step b/: an electrically insulating layer 8 is then printed on the aluminum foil 4 according to an interlocking pattern (FIG. 7B). As illustrated, this pattern is formed of a plurality of parallel bands connected by a main band. In other words, this interlocking pattern forms an interdigitating comb.

[0135] The insulating layer 8 is preferably made of polymer, more preferably chosen from polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP).

[0136] Step c/: a carbon or copper layer 5 is then printed on the electrically insulating layer 8, forming a negative current collector (FIG. 7C). As illustrated, the carbon or copper layer 5 is deposited on the interlocking pattern of the insulating layer 7.

[0137] Step d/: a layer of positive electrode active material 2 is then printed on the aluminum foil 4 according to a pattern at least partly interlocked in the interlocking pattern (FIG. 7D), that is to say according to a comb complementary to the interdigitating comb already produced with the insulating layer 7 and current collector layer 5. The aluminum foil 4 covered with the printed layer 2 then forms the cathode of the accumulator.

[0138] Step e/: a layer of negative electrode active material 3 is then printed, at the same time as or with a time lag relative to step d/, on the current collector layer 5 according to the interlocking pattern (FIG. 7D).

[0139] Thus, after the printing of the positive 2 and negative 3 active layers, the interdigitated pattern is formed, only one end respectively of the aluminum foil 4 stamped on the substrate 7 and of the copper or carbon layer 5 protruding in order to be able to produce the electrical interconnection with the outside of the accumulator A.

[0140] Step f/: a layer of electrolyte 1 is then printed at least in the spaces separating the two positive 2 and negative 3 layers (FIG. 7E). In the example illustrated, the layer of electrolyte 1 covers all of the components with the exception of the electrical connection ends.

[0141] All the functional layers of the accumulator can then be covered with a package, preferably by encapsulation using an electrically and thermally insulating material.

[0142] By producing the positive current collector 4 by stamping of an aluminum foil, the Li-ion accumulator retains all the advantages of an Li-ion accumulator as described in application FR3007207 A1 with, in addition, the possibility of an increased energy density, and this with a great compactness.

[0143] Illustrated in FIG. 8 is a rectangular spiral architecture of an Li-ion accumulator that it is possible to obtain by means of the invention.

[0144] Such an accumulator may advantageously be used directly as part of an object, in particular of an electronic device, the electric power supply of which is provided by the accumulator. For example, the geometry illustrated in FIG. 8 could be printed inside an aluminum casing shell of a cell phone, which would make it possible to considerably reduce the thickness of the phone.

[0145] In this configuration, it is also advantageously possible to do away with an insulating substrate 7 and with a metal foil 4 in its current form, the metal element forming the current collector advantageously being formed by the aluminum shell of the cell phone casing.

[0146] By way of exemplary embodiment, an accumulator according to the invention may be produced with an aluminum foil 4 coated with a printed layer 2, of positive active material on top, for example LiNi.sub.0.33Mn.sub.0.33Co.sub.0.33O.sub.2. Next to the positive layer 2 a layer of insulating polymer 8 is printed, defining the interlocking pattern. On this insulating layer 8, a copper layer 5 is printed according to the same pattern then, on this copper layer 5, a layer 3 of anode active material, for example made of Li.sub.4Ti.sub.5O.sub.12, is printed.

[0147] Other variants and advantages of the invention may be produced without however departing from the scope of the invention.

[0148] The invention is not limited to the examples which have just been described; features of the examples illustrated may in particular be combined together in variants that have not been illustrated.