ELECTROCHEMICAL CELL, ENERGY STORAGE SYSTEM AND VEHICLE COMPRISING SUCH A SYSTEM

Abstract

An electrochemical cell including a shell delimiting a space filled with an electrolytic solution, and a set of at least two different electrochemical systems selected from among a supercapacitor, a hybrid supercapacitor, and an accumulator, the set being arranged in the space filled with the electrolytic solution. A system for storing and restoring electric energy, or a vehicle, or a hybrid vehicle car can include such an electrochemical cell and can include such a system for storing and restoring electric energy.

Claims

1-21 (canceled)

22. An electrochemical cell comprising: a shell delimiting a space filled with an electrolytic solution; and a set of at least two different electrochemical systems selected from a supercapacitor, a hybrid supercapacitor, and an accumulator; wherein the supercapacitor comprises a positive electrode comprising activated carbon and a negative electrode comprising activated carbon; the hybrid supercapacitor comprises a positive electrode comprising activated carbon and a negative electrode comprising a metal or a carbonaceous material for intercalating at least one alkaline metal noted as M, the material being different from the activated carbon used at the positive electrode; the accumulator comprises a positive electrode comprising an oxide, or a polyanionic compound, of a transition metal and a negative electrode comprising a carbonaceous material for intercalating at least one alkaline metal noted as M; and wherein the set is arranged in a space filled with the electrolytic solution.

23. The electrochemical cell according to claim 22, wherein the set comprises the hybrid supercapacitor.

24. The electrochemical cell according to claim 23, wherein the set further comprises the supercapacitor.

25. The electrochemical cell according to claim 24, wherein the positive electrode of the hybrid supercapacitor is also the positive electrode of the supercapacitor.

26. The electrochemical cell according to claim 23, wherein the set further comprises the accumulator.

27. The electrochemical cell according to claim 26, wherein the negative electrode of the hybrid supercapacitor, when it comprises the carbonaceous material for intercalating at least one alkaline metal M, is also the negative electrode of the accumulator.

28. The electrochemical cell according to claim 22, wherein the set comprises the supercapacitor, the hybrid supercapacitor, and the accumulator.

29. The electrochemical cell according to claim 22, wherein the electrolytic solution comprises at least one solvent and at least one electrolyte, the electrolyte comprising an alkaline metal salt fitting the formula MA and comprising a cation M.sup.+ of the alkaline metal M and an anionic group A.sup..

30. The electrochemical cell according to claim 22, wherein the alkaline metal M is selected from Li, Na, K, Rb, Cs and mixtures thereof.

31. The electrochemical cell according to claim 29, wherein the anionic group A.sup. is selected from ClO.sub.4.sup., AlCl.sub.4.sup., BF.sub.4.sup., PF.sub.6.sup., SbF.sub.6.sup., AsF.sub.6.sup., SiF.sub.6.sup., SCN.sup., FSI.sup., TFSI.sup., BOB.sup., ODBF.sup., SO.sub.3CF.sub.3.sup. and mixtures thereof.

32. The electrochemical cell according to claim 29, wherein the electrolyte is KPF.sub.6.

33. The electrochemical cell according to claim 29, wherein the solvent is an organic solvent, or selected from a nitrile solvent, a carbonate solvent, a lactone solvent, a sulfone solvent, a lactam solvent, an amide solvent, a ketone solvent, a nitroalkane solvent, an amine solvent, a sulfoxide solvent, an ester solvent, an ether solvent, an oxazolidone solvent, and mixtures thereof.

34. The electrochemical cell according to claim 29, wherein the electrolyte is present in the electrolytic solution in a molar concentration between 0.5 mol/l and 2 mol/l.

35. The electrochemical cell according to claim 22, wherein at least one of the electrochemical systems comprises, arranged between its positive and negative electrodes, at least one electrically non-conductive separation membrane.

36. The electrochemical cell according to claim 22, wherein at least one of the electrodes of the electrochemical systems comprises a current collector, the current collector appearing as a metal sheet.

37. The electrochemical cell according to claim 22, wherein, when the electrode comprises activated carbon, the activated carbon is present in a mass content of at least 60% based on total mass of the relevant electrode.

38. The electrochemical cell according to claim 22, wherein the carbonaceous material for intercalating at least one alkaline metal M is graphite.

39. The electrochemical cell according to claim 22, being a cylindrical cell, a button cell, or a pouch cell.

40. A system for storing and restoring electric energy comprising an electrochemical cell according to claim 22 and at least one electronic interface configured to select an electrochemical system according to a degree of hybridization.

41. The system for storing and restoring electric energy according to claim 40, wherein the electronic interface is further configured to control exchange of electric energy between the electrochemical systems.

42. A vehicle, in particular a hybrid vehicle, comprising at least one system for storing and restoring electric energy according to claim 40.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0106] FIG. 1 is a photograph of an electrochemical cell according to the invention comprising two electrochemical systems, a supercapacitor and a hybrid supercapacitor, each electrochemical system comprising a positive electrode and a negative electrode.

[0107] FIG. 2 is a schematic illustration in a longitudinal sectional view of the internal structure of the electrochemical cell of FIG. 1.

[0108] FIG. 3 illustrates the curve obtained in cyclic voltammetry expressing the change in the current (noted as I and expressed in mA) according to the potential difference (noted as E and expressed in V) applied between the positive and negative electrodes of the electrochemical system formed by the hybrid supercapacitor of the electrochemical cell of FIG. 1.

[0109] FIG. 4 illustrates the curve obtained in cyclic voltammetry expressing the change in the current (noted as I and expressed in mA) depending on the potential difference (noted as E and expressed in V) applied between the positive and negative electrodes of the electrochemical system formed by the supercapacitor of the electrochemical cell of FIG. 1.

[0110] FIG. 5 is a photograph of an electrochemical cell according to the invention comprising two electrochemical systems, a supercapacitor and a hybrid supercapacitor, both of these electrochemical systems sharing the same positive electrode.

[0111] FIG. 6 is a schematic illustration in a longitudinal sectional view of the internal structure of the electrochemical cell of FIG. 5.

[0112] FIG. 7 illustrates the curve obtained in cyclic voltammetry expressing the change in the current (noted as I and expressed in mA) depending on the potential difference (noted as E and expressed in V) applied between the positive and negative electrodes of the electrochemical system formed by the hybrid supercapacitor of the electrochemical cell of FIG. 5.

[0113] FIG. 8 illustrates the curve obtained in cyclic voltammetry expressing the change in the current (noted as I and expressed in mA) depending on the potential difference (noted as E and expressed in V) applied between the positive and negative electrodes of the electrochemical system formed by the supercapacitor of the electrochemical cell of FIG. 5.

[0114] FIG. 9 is a block diagram of a system for storing and restoring electric energy according to the invention.

[0115] It is specified that the elements common to FIGS. 1, 2, 5 and 6 are identified by the same numerical reference.

DETAILED DISCUSSION OF PARTICULAR EMBODIMENTS

[0116] The present examples 1 and 2 illustrate the behavior of an electrochemical cell according to the invention and applying a set of two different electrochemical systems, a supercapacitor and a hybrid supercapacitor.

[0117] Example 3 illustrates a system for storing and restoring electric energy according to the invention.

[0118] Each electrode used within the scope of these examples 1 and 2 was prepared by coating, on an aluminium collector with a thickness of 30 m, of one or the other of the compositions A and B below.

[0119] Composition A, which allows preparation of an electrode comprising activated carbon, comprises, in a mass percentage based on the total mass of said composition A: [0120] 84% of activated carbon of reference YP-50F marketed by Kuraray Chemical, [0121] 4% of styrene-butadiene binder of reference Styrofan LD 417 marketed by BASF, [0122] 8% of carbon black of reference C-NERGY SUPER C65 marketed by Timcal, and [0123] 4% of carboxymethylcellulose (2% by mass in water) of reference 7HXF marketed by Aqualon.

[0124] Composition B, which allows preparation of an electrode comprising graphite as a material for intercalating at least one alkaline metal, comprises in mass percentage based on the total mass of said composition B: [0125] 94% of graphite carbon of reference Timrex SLP30 marketed by Timcal, [0126] 2% of carbon black of reference C-NERGY SUPER C65 marketed by Timcal, [0127] 2% of carboxymethylcellulose (2% by mass in water) of reference 7HXF marketed by Aqualon, and [0128] 2% of styrene-butadiene binder of reference Styrofan LD 417 marketed by BASF.

[0129] The electrodes were separated by means of microporous separation membranes with a thickness of 25 m and of reference TreoPore PDA 25 marketed by Treofan.

[0130] The electrolytic solution used comprises potassium hexafluorophosphate KPF.sub.6 as an electrolyte, at a molar concentration of 1 mol/l in acetonitrile as a solvent.

EXAMPLE 1

Electrochemical Cell with Four Electrodes

[0131] The electrochemical cell of Example 1, noted as C.sub.1, a photograph of which is reproduced in FIG. 1, appears as a pouch cell.

[0132] With reference to the schematic illustration of FIG. 2, this electrochemical cell C.sub.1 comprises a shell 1 delimiting a space 2 which is filled with an electrolytic solution 3, the composition of which has been detailed earlier (KPF.sub.6 in 1M acetonitrile).

[0133] The electrochemical cell C.sub.1 moreover comprises a set of two electrochemical systems S.sub.1 and S.sub.2.

[0134] The electrochemical system S.sub.1, which is a hybrid supercapacitor, comprises a positive electrode 4 and a negative electrode 5. The positive electrode 4 is formed by coating the composition A on the aluminium collector, the end of which is visible on the photograph of FIG. 1. The negative electrode 5 is formed by coating the composition B on the aluminium collector, the end of which is also visible on the photograph of FIG. 1. The electrochemical system S.sub.1 further comprises a separation membrane 6 arranged between the positive electrode 4 and the negative electrode 5.

[0135] The electrochemical system S.sub.2, which is a supercapacitor, comprises a positive electrode 7 and a negative electrode 8, these electrodes 7 and 8 both being formed by coating, on their respective aluminium collector, the respective ends of which are also visible on the photograph of FIG. 1, of the composition A described above. The electrochemical system S.sub.2 further comprises a separation membrane 9 arranged between the positive electrode 7 and the negative electrode 8.

[0136] The electrochemical cell C.sub.1 further comprises a separation membrane 10 arranged between the electrochemical systems S.sub.1 and S.sub.2.

[0137] Cyclic voltammetry tests were conducted for confirming the operation of each of the electrochemical systems S.sub.1 and S.sub.2 of the electrochemical cell C.sub.1.

[0138] In a first step, the cyclic voltammetry test was conducted for evaluating the operation of the electrochemical system S.sub.1, by producing the electric connection between the positive electrode 4 and the negative electrode 5. The corresponding curve as obtained during cycling carried out at a sweep rate of 10 mV/s, is illustrated in FIG. 3.

[0139] It is observed that this curve of FIG. 3 corresponds to a typical voltammogram of a hybrid supercapacitor, this voltammogram comprising a first portion, located between 0.5 V and 1.5 V, which has the aspect of a supercapacitor, and a second portion, located between 1.5 V and 3.2 V, which has the aspect of an accumulator. The electrochemical system S.sub.1 of the electrochemical cell C.sub.1 is therefore actually functional.

[0140] In a second step, the cyclic voltammetry test was conducted for evaluating the operation of the electrochemical system S.sub.2, by producing the electric connection between the positive electrode 7 and the negative electrode 8. The corresponding curve as obtained during cycling carried out at a sweep rate of 10 mV/s, is illustrated in FIG. 4.

[0141] It is observed that this curve of FIG. 4 corresponds to a typical voltammogram of a supercapacitor, demonstrating that the electrochemical system S.sub.2 of the electrochemical cell C.sub.1 is therefore also actually functional.

EXAMPLE 2

Electrochemical Cell with Three Electrodes

[0142] The electrochemical cell of Example 2, noted as C.sub.2, a photograph of which is reproduced in FIG. 5, also appears as a pouch cell.

[0143] With reference to the schematic illustration of FIG. 6, this electrochemical cell C.sub.2 comprises a shell 1 delimiting a space 2 which is filled with the same electrolytic solution 3 as the one used in the electrochemical cell C.sub.1 of Example 1 (KPF.sub.6 in 1M acetonitrile).

[0144] The electrochemical cell C.sub.2 moreover comprises a set formed with two electrochemical systems S.sub.3 and S.sub.4.

[0145] The electrochemical system S.sub.3 is a hybrid supercapacitor and comprises a positive electrode 4 as well as a negative electrode 5. Like in the electrochemical system S.sub.1 of Example 1, the positive electrode 4 of the electrochemical cell C.sub.2 is obtained by coating the composition A on a first aluminium collector, while the negative electrode 5 is obtained by coating the composition B on a second aluminium collector. The electrochemical system S.sub.3 further comprises a separation membrane 6 arranged between the positive electrode 4 and the negative electrode 5.

[0146] The electrochemical system S.sub.4 is a supercapacitor and comprises as a positive electrode, the positive electrode 4 as well as a negative electrode 8. This negative electrode 8 is also obtained by coating the composition A on a third aluminium collector. The electrochemical system S.sub.4 further comprises a separation membrane 9 arranged between the positive electrode 4 and the negative electrode 8.

[0147] The positive electrode 4 is therefore an electrode common to the two electrochemical systems S.sub.3 and S.sub.4 since it makes up both the positive electrode of the electrochemical system S.sub.3 and the positive electrode of the electrochemical system S.sub.4. Consequently, and by design, no additional separation membrane is arranged between the electrochemical systems S.sub.3 and S.sub.4.

[0148] Cyclic voltammetry tests were conducted for confirming the operation of each of the electrochemical systems S.sub.3 and S.sub.4 of the electrochemical cell C.sub.2.

[0149] In a first step, the cyclic voltammetry test was conducted in order to evaluate the operation of the electrochemical system S.sub.3, by producing the electric connection between the positive electrode 4 and the negative electrode 5. The corresponding curve as obtained during cycling carried out at a sweep rate of 10 mV/s, is illustrated in FIG. 7.

[0150] It is observed that this curve of FIG. 7 has a similar aspect to that of the curve of FIG. 3 and therefore corresponds to a typical voltammogram of a hybrid supercapacitor, with a first curve portion characteristic of a supercapacitor, and a second portion characteristic of an accumulator. The electrochemical system S.sub.3 of the electrochemical cell C.sub.2 is therefore actually functional.

[0151] In a second step, the cyclic voltammetry test was conducted for evaluating the operation of the electrochemical system S.sub.4, by producing the electric connection between the positive electrode 4 and the negative electrode 8. The corresponding curve as obtained during cycling carried out at a sweep rate of 10 mV/s, is illustrated in FIG. 8.

[0152] It is observed that this curve of FIG. 8 has a similar aspect to that of the curve of FIG. 4 and therefore corresponds to a typical voltammogram of a supercapacitor, demonstrating that the electrochemical system S.sub.4 of the electrochemical cell C.sub.2 is therefore also actually functional.

EXAMPLE 3

System for Storing and Restoring Electric Energy

[0153] A system for storing and restoring electric energy according to the invention is illustrated in FIG. 9.

[0154] This system for storing and restoring electric energy 11 comprises an electrochemical cell 12 and an electronic interface 13.

[0155] The electrochemical cell 12 comprises a shell 14 delimiting a space 15 in which is arranged a set formed with three different electrochemical systems 16, 17, 18, i.e. a supercapacitor, a hybrid supercapacitor and an accumulator. This space 15 further comprises an electrolytic solution 19 formed with a solvent and an electrolyte, this electrolytic solution 19 being compatible with the operation of each of the electrochemical systems 16, 17 and 18.

[0156] Each electrochemical system 16, 17, 18 is connected to the electronic interface 13, with connection means, respectively 16, 17, 18.

[0157] The electronic interface 13 is adapted for the selection of an electrochemical system, from among the three electrochemical systems 16, 17 and 18 of the electrochemical cell 12, according to a degree of hybridization.

[0158] This electronic interface 13 is further advantageously adapted for controlling the exchange of electric energy between the electrochemical systems 16, 17 and 18.