Electrochemical storage device having improved electrical conduction properties

Abstract

An electrochemical storage device has an anode chamber filled with anode material during operation, and a cathode chamber filled with cathode material. The anode chamber is separated from the cathode chamber by solid body electrolyte guiding ions, and the anode chamber is limited on one side by the solid body electrolyte, on another side by a wall at least partially surrounding the solid body electrolyte. The wall is surrounded by a head part of the device, by a base part arranged opposite the head part and/or by a lateral part arranged between the head and base part. The wall has an electrical conductive wall section as an anode to the anode chamber, an at least partially flat, electrical conductive line section electrically connected to the wall section by a surface, and conductivity per surface of the line section greater than conductivity of the wall per surface of the wall section.

Claims

1. An electrochemical storage device comprising: an anode compartment filled with an anode material and a cathode compartment filled with a cathode material when in operation, wherein the anode compartment is separated from the cathode compartment by an ion-conductive solid electrolyte, and wherein the anode compartment is delimited on one side at least in part by the solid electrolyte and on another side at least in part by a wall which surrounds the solid electrolyte at least in part, wherein the wall is comprised of a top part of the electrochemical storage device, a bottom part arranged opposite the top part, and/or a side part arranged between top part and bottom part, and wherein the wall has an electrically conductive wall portion with a surface profile facing away from the electrochemical storage device, which is associated as an anode to the anode compartment, wherein an at least partly flat, electrically conductive conductor portion is electrically connected with the surface profile of the wall portion via a surface and wherein an electrical conductivity per unit area of the conductor portion is greater than that of the wall per unit area of the wall portion, wherein the wall portion has a wall thickness which is less than the thickness of the at least partly flat conductor portion in the region of the surface.

2. The electrochemical storage device as claimed in claim 1, wherein the surface of the conductor portion is adapted to the surface profile of the wall portion.

3. The electrochemical storage device as claimed in claim 1, wherein the wall portion and the at least partly flat conductor portion are metallic and connected together in a mechanically load-bearing manner via a strong metallic connection.

4. The electrochemical storage device as claimed in claim 1, wherein the wall portion is arranged closer to the top part than to the bottom part.

5. The electrochemical storage device as claimed in claim 1, wherein the wall portion is arranged at the side part.

6. The electrochemical storage device as claimed in claim 1, wherein the at least partly flat conductor portion partly or completely surrounds the top part.

7. The electrochemical storage device as claimed in claim 1, wherein the at least partly flat conductor portion projects above the top part.

8. The electrochemical storage device as claimed in claim 1, wherein the conductor portion has a surface on which an electrical insulator is mounted.

9. The electrochemical storage device as claimed in claim 1, wherein the electrically conductive wall portion is comprised by the side part, which is made from shaped sheet metal.

10. A thermal module for storing and releasing electrical energy, comprising multiple electrically interconnected electrochemical storage devices as claimed in claim 1, wherein the at least partly flat conductor portion is contacted electrically with suitable electrical leads for infeed and outfeed of electrical charge to the anode.

11. The thermal module as claimed in claim 10, wherein the conductor portion is also configured as a support, which supports the electrochemical storage devices against other electrochemical storage devices, against other supports of other electrochemical storage devices and/or against a module surface.

12. The thermal module as claimed in claim 10, wherein the at least partly flat conductor portion has a suitably shaped receptacle for an insulator.

13. The electrochemical storage device as claimed in claim 3, wherein the strong metallic connection comprises a welded joint.

14. The electrochemical storage device as claimed in claim 6, wherein the at least partly flat conductor portion is arranged around the top part as a conduction sleeve.

15. The electrochemical storage device as claimed in claim 8, wherein the surface on which an electrical insulator is mounted comprises a surface facing away from the electrochemical storage device.

16. The electrochemical storage device as claimed in claim 1, wherein the electrical connection between the wall portion and the at least partly flat conductor portion is brought about by a flux material that connects the conductor portion with the wall portion by a welded joint.

17. The electrochemical storage device as claimed in claim 1, further comprising a contacting means that is electrically connected with the conductor portion and wherein the contacting means is not directly electrically connected with the wall portion.

18. The electrochemical storage device as claimed in claim 17, wherein the contacting means is electrically connected with the conductor portion via a welding material.

19. The electrochemical storage device as claimed in claim 1, wherein the wall portion and the conductor portion are in direct mechanical contact such that the electrical connection between the wall portion and the conductor portion is brought about by direct contact alone.

20. The electrochemical storage device as claimed in claim 1, wherein the conductor portion is positioned on a side of the wall portion facing away from the electrical storage device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures:

(2) FIG. 1 shows a schematic representation of a sectional view from the side through a first embodiment of an electrochemical storage device according to the invention;

(3) FIG. 2 shows an enlarged representation of the region of the wall portion and conductor portion in lateral sectional view as may for instance be comprised by an electrochemical storage device according to the embodiment as shown in FIG. 1;

(4) FIG. 3 shows an enlarged representation of the region of the wall portion and conductor portion in lateral sectional view as may for instance be comprised by an electrochemical storage device according to the embodiment as shown in FIG. 1;

(5) FIG. 4 shows an enlarged representation of the region of the wall portion and conductor portion in lateral sectional view as may for instance be comprised by an electrochemical storage device according to the embodiment as shown in FIG. 1;

(6) FIG. 5 shows an enlarged representation of the region of the wall portion and conductor portion in lateral sectional view as may for instance be comprised by an electrochemical storage device according to the embodiment as shown in FIG. 1;

(7) FIG. 6 shows a first embodiment of a thermal module according to the invention in lateral sectional view.

DETAILED DESCRIPTION OF INVENTION

(8) FIG. 1 shows a lateral sectional view through a first embodiment of an electrochemical storage device 100 according to the invention, which has an anode compartment 11 separated from a cathode compartment 21 by a solid electrolyte 30. In a typical operating state as shown here, the anode compartment 11 is filled with anode material 10. The cathode compartment 21 is likewise filled with cathode material 20. The solid electrolyte 30 is here of can-shaped construction.

(9) According to sodium-nickel chloride cell technology, the anode material is elemental sodium which assumes liquid form at the operating temperature of the storage device 100 (for instance between 200 C. and 350 C.).

(10) The filling level of the liquid content of cathode material 20 in the cathode compartment 21 correlates, depending on the state of charge of the electrochemical storage device 100, with the filling level of the anode compartment 11. In the present case, the cathode material 20 in particular comprises a cathode 25, together with a cathode salt 26 and a cathode electrolyte 27, which are here shown as one. According to sodium-nickel chloride cell technology, the cathode 25 takes the form for example of metallic nickel bar (nickel wire) which is surrounded by metallic nickel powder, and the cathode salt 26 the form of sodium chloride.

(11) In the region of the top part 110 of the electrochemical storage device 100, the cathode 25 permits electrical contacting in order to feed electrical charge in or out, depending on the state of charge or discharge of the storage device 100. The anode of the electrochemical storage device 100 is formed by the side part which is also made of metal. The side part 130 is in turn part of a can 41 which comprises both the bottom part 120 and the side part 130. Sealing of the electrochemical storage device 100 in the region of the top part 110 may proceed according to teaching known from the prior art.

(12) The solid electrolyte 30 comprised by the electrochemical storage device 100 permits a specific ion conductivity, but without enabling any further mass exchange between the anode compartment 11 and cathode compartment 21. According to sodium-nickel chloride cell technology, the solid electrolyte 30 takes the form of -Al.sub.2O.sub.3 or -Al.sub.2O.sub.3 and for example enables selective Na+ ion conductivity. In this respect, on charging of the electrochemical storage device 100, the Na+ ions are capable of migrating from the cathode compartment into the anode compartment, wherein they are reduced there to elemental sodium by the provision of electrons. Over the course of the charging process, said elemental sodium accumulates to an increasing extent in the anode compartment.

(13) If the electrochemical storage device 100 is discharged, Na+ ion transport proceeds in the opposite direction, wherein sodium is oxidized at the interface between the solid electrolyte and the anode material, after which the resultant Na+ ion migrates through the solid electrolyte into the cathode compartment 21. The filling level of anode material 10 in the anode compartment 11 and of cathode electrolyte 27 in the cathode compartment 21 thus differs depending on the state of charge or discharge.

(14) In addition to electrical contacting via the cathode 25, the electrochemical storage device 100 allows electrical contacting of the anode 12 via a contacting means 80. This contacting means 80, which need not here also be claimed, may for example take the form of a conducting lug. The contacting means 80 is electrically connected with the conductor portion 50, wherein the conductor portion 50 is itself electrically connected with the wall portion 45 of the wall 40. In the case of electrical operation of the electrochemical storage device 100, electrical charge may thus be conducted via the wall portion 45 to the conductor portion 50 and from there subsequently to the contacting means 80. According to the embodiment, the conductor portion 50 has a suitable surface profile, such that one surface 55 is adapted to the surface profile of the wall portion 45. Consequently, suitable, advantageous electrical conduction, supported by the geometry, of charge carriers may proceed between conductor portion 50 and wall portion 45.

(15) To reduce ohmic losses in the region of electrical contact with the contacting means 80, according to the invention the contacting means 80 is not electrically connected directly with the wall portion 45 of the wall 40, but rather merely through the intermediary of the conductor portion 50. The conductivity per unit area of the conductor portion 50 is here greater than that of the wall 40 per unit area of the wall portion 45. In other words, the surface conductivity of the conductor portion 50 is greater than that of the wall portion 45. In this way, even on exposure to relatively high current densities the ohmic losses in this region are kept low, such that the thermal power loss during operation of the electrochemical storage device 100 is at an advantageous level.

(16) The region of contact between conductor portion 50 and wall portion 45 is shown on an enlarged scale and in detail below with reference to various possible embodiments.

(17) FIG. 2 shows a first embodiment of such an enlarged region of the wall 40, at which the conductor portion 50 is brought into electrical connection with the wall portion 45 via a surface 55. The electrical connection between wall portion 45 and the surface 55 of the conductor portion 50 is brought about by a flux material 70, which is a welding material for example. The flux material 70 may or indeed may not be a third material. In particular, the flux material 70 is welded metal, which connects the conductor portion 50 with the wall portion 45 by a welded joint.

(18) The cross-sectional representation shows that both the wall portion 45 and the conductor portion 50 are substantially flat. In this case, one direction of extension of the component (from top to bottom in the image plane) has a distinctly greater extent compared with the other, perpendicular directions of extension (from left to right in the image plane). In the present case, according to the orientation shown here the extent from top to bottom is thus distinctly greater than the extent for instance from right to left. As a result of the different thicknesses of these flat components, i.e. of wall portion 45 and of conductor portion 50, a different surface conductivity is obtained for the respective components. It is thus clear that the ohmic losses for a relatively thicker component such as the conductor portion 50 are lower than for the relatively thinner component, i.e. for the wall portion 45.

(19) In particular, on exposure of the respective components to charges at relatively high current densities, the conductor portion 50 thus allows lower ohmic conduction losses due to its relatively greater thickness. However, since the conductor portion 50 has better conduction behavior and furthermore is also areally connected with the wall portion 45, such that on exposure to a high current density the charge carriers may be suitably conducted in areally distributed manner, thermal loss may be reduced on operation of the electrochemical storage device 100. This in turn increases overall efficiency on operation of the electrochemical storage device 100.

(20) According to the embodiment, the contacting means 80 is in turn connected to the conductor portion 50 via a flux material 75, which allows suitable electrical contacting. The flux material 75 is particularly in turn welding material.

(21) FIG. 3 shows a further embodiment of the possible connection of conductor portion 50 and wall portion 45, as may be provided for example in the embodiment of the electrochemical storage device 100 according to FIG. 1. Here the embodiment according to FIG. 3 differs from the embodiment shown in FIG. 2 merely in that contacting of the conductor portion 50 and wall portion 45 is achieved not by a flux material 70 but by the two being in direct mechanical contact. If both are of suitable metallic construction and optionally protected against oxidation by a conductive surface layer, this direct contact alone is sufficient for electrical contacting. Contacting of conductor portion 50 and wall portion 45 in particular proceeds by plug-in contact or clamping contact.

(22) FIG. 4 shows a further embodiment of the connection region of conductor portion 50 and wall portion 45, which is substantially like the embodiment according to FIG. 2. In addition, however, the conductor portion 50 comprises an insulator 60 directed away from the wall 40. If two electrochemical storage devices 100 are arranged next to one another in a thermal module 200 (not shown in any greater detail), said insulator is configured for instance to keep these two at a sufficient distance from one another and to insulate them electrically from one another. In the present case, the insulator 60 is provided with a rounded portion in the cross-sectional view shown.

(23) As an alternative to the embodiment shown in FIG. 4, it is possible, as shown in FIG. 5, for the insulator 60 also to be placed onto the end of the conductor portion 50. In this case, the conductor portion 50 extends above the wall portion 45, or beyond above the top part 110 (not shown in any greater detail), such that a tab or a collar is present. A suitably shaped insulator 60 may be mounted on the end thereof. To contact the contacting means 80, the latter is then contacted in a different region of the conductor portion 50 compared with the embodiment shown in FIG. 4. However it is important in this case for the contacting means 80 not to put at risk the insulating action of the insulator 60. It is feasible, for example, that the contacting means 80 of adjacent electrochemical storage devices 100 are guided past the insulators 60 at various locations such that no electrical contact results. It is likewise conceivable that the contacting means 80 is guided within the insulator 60.

(24) FIG. 6 shows an embodiment of the thermal module 200 according to the invention, which has multiple electrically interconnected electrochemical storage devices 100. The individual electrochemical storage devices 100 here substantially resemble the embodiment shown in FIG. 1. For suitable in- and outfeed of electrical charge at the anode 12, the conductor portions 50 are each in electrical contact with a contacting means 80. The contacting means 80 are in turn electrically interconnected together. For spacing and electrical insulation of individual, mutually adjacent electrochemical storage devices 100, insulators 60 are provided which are provided in the region of the conductor portions 50.

(25) Further embodiments are revealed by the subclaims.