Abstract
A measuring arrangement for secondary alkaline solid electrolyte batteries comprising—two electrically non-conductive cell body halves, both cell body halves comprising at least one and one cell body half comprising at least three feedthroughs, both cell body halves forming a receiving space for receiving a solid electrolyte battery cell comprising at least an anode, a cathode and a solid electrolyte. An electrically conductive holding element for each feedthrough; an electrical contact element for each support element, the electrical contact element being adapted to change its length in response to the force applied to the element; and two planar current conductors comprising electrically conductive and electrically non-conductive regions, at least one of the current conductors being adapted to form at least three separate electrically conductive connections between the contact elements and an electrode of the solid electrolyte battery cell.
Claims
1. Electrical measuring arrangement for secondary alkaline solid electrolyte batteries, wherein the measuring arrangement comprises at least: two electrically non-conductive cell body halves, both cell body halves comprising at least one and one cell body half comprising at least three feedthroughs, both cell body halves each having a recess on an inside, the recesses together forming a receiving space for receiving a solid electrolyte battery cell comprising at least an anode, a cathode, and a solid electrolyte, and the feedthroughs each extending from an outer side of the cell body half towards the receiving space; an electrically conductive retaining element for each feedthrough, the retaining element being equipped to be mechanically connectable to the respective cell body half; an electrical contact element for each retaining element, the electrical contact element being attachable to the retaining element towards the receiving space and being adapted to change its length in dependence on force acting on the electrical contact element; and two flat current conductors comprising electrically conductive and electrically non-conductive regions, at least one of the current conductors being equipped to form at least three separate, electrically conductive connections between the electrical contact elements and an electrode of the solid electrolyte battery cell, wherein a mechanical force of the electrical contact elements is applied to the solid electrolyte battery via the current conductors.
2. The measuring arrangement according to claim 1, wherein the receiving space is rotationally symmetrical.
3. The measuring arrangement according to claim 1, wherein the different electrical contact elements of each cell body half comprise different metals.
4. The measuring arrangement according to claim 1, wherein the electrical contact element is a spring contact and the arrangement of the electrical contact elements is rotationally symmetrical towards the receiving space.
5. The measuring arrangement according to claim 4, wherein each measuring body half has four feedthroughs, four holding elements and four electrical contact elements, wherein one of the electrical contact elements is arranged centrally and the further three electrical contact elements are arranged on a circular path around a central electrical contact element and the three further contact elements are arranged on a circular path offset by 120° in each case.
6. The measuring arrangement according to claim 5, wherein the electrical contact elements of the lower and upper cell body halves are arranged by 60° offset from each other during measurement.
7. The measuring arrangement according to claim 1, wherein the current conductors have recesses at the points at which the current conductors are electrically contacted by the electrical contact elements.
8. The measuring arrangement according to claim 1, wherein one of the current conductors has a cylindrical geometry and the other current conductor has a cylindrical geometry with rounded edges.
9. The measuring arrangement according to claim 1, wherein each of the current conductors has a recess towards the inside of the receiving space, the recess being adapted to receive an electrode of the solid electrolyte battery.
10. The measuring arrangement according to claim 4, wherein the spring contacts have a spring constant of greater than or equal to 0.05 N and less than or equal to 50 N.
11. Use of a measuring arrangement according to claim 1, for determining the electrical properties of secondary alkali solid electrolyte battery cells.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0032] Further advantages and advantageous embodiments of the objects according to the disclosure are illustrated by the drawings and explained in the following description. It should be noted that the drawings are descriptive only and are not intended to limit the invention in any way. It shows the
[0033] FIG. 1 a schematic side view of an embodiment of a cell body half (bottom);
[0034] FIG. 2 a schematic top view of an embodiment of a cell body half (bottom);
[0035] FIG. 3 a schematic bottom view of an embodiment of a cell body half (bottom);
[0036] FIG. 4 a schematic side view of an embodiment of a cell body half (top);
[0037] FIG. 5 a schematic top view of an embodiment of a cell body half (top);
[0038] FIG. 6 a schematic top view of an embodiment of a cell body half (top);
[0039] FIG. 7 a schematic section through an embodiment of a cell body half (bottom);
[0040] FIG. 8 a schematic section through an embodiment of a cell body half (top);
[0041] FIG. 9 a schematic top view of an embodiment of a cell body half with 4 different contact elements;
[0042] FIG. 10 a schematic top view of an embodiment of a current collector (bottom);
[0043] FIG. 11 a schematic top view of an embodiment of a current collector with embedded electrode layer (bottom);
[0044] FIG. 12 a schematic top view of an embodiment of a current collector (top);
[0045] FIG. 13 a schematic cross-section of a current collector (top);
[0046] FIG. 14 a schematic cross-section of a current collector (bottom);
[0047] FIG. 15 a schematic cross-section of a current collector with embedded electrode layer (bottom);
[0048] FIG. 16 a schematic cross-section of a current collector for a four-electrode insert;
[0049] FIG. 17 a measurement series of an NMC622/Li half cell, plotted is the voltage as a function of the specific capacitance.
DETAILED DESCRIPTION
[0050] FIG. 1 shows a schematic side view of a cell body half 1. The cell body half 1 shown may be referred to, for example, as a lower cell body half 1. The actual cell body 2 may be made of a plastic such as PEEK. The cell body half 1 is configured to be combined with another cell body half 1. For this purpose, the cell body half 1 has bores 5 through which both cell body halves 1 can be connected to each other. For example, screws can be guided through the holes 5, through which both cell body halves 1 can be screwed together. The cell body half 1 shown also has an optional groove 6, which can accommodate an O-ring. Furthermore, this view shows the contact elements 4 and the receiving space 3 in which the battery cell can be placed for the actual measurement.
[0051] FIG. 2 shows a top view of a cell body half 1. The actual cell body 2 with holes 5, the optional recess for an O-ring 6, the individual contact elements 4, here in this example there are four individual contact elements 4, and the receiving space 3 for the actual battery cell are shown.
[0052] FIG. 3 shows a view of a cell body half 1 from below. In this figure, the actual cell body 2, the three holes for connecting two cell body halves 1 and the retaining elements 7 can be seen. The retaining elements 7 may be mechanically connected to the actual cell body 2, for example in the form of screws. The retaining elements 7 can be stainless steel screws, for example, which lead from the underside of the cell body half 1 to the receiving space. The stainless steel screws have a recess for a spring contact (not shown) at the end pointing into the cell interior. This allows simple, flexible replacement of damaged spring contacts when unscrewing or the use of spring contacts with other spring constants to change the contact pressure inside the cell. The retaining elements 7 are held gas-tight towards the outside by an O-sealing ring (placed in a sealing ring groove), which is pressed against the body by the screw head. At the same time, a 4 mm diameter hole can lead into the screw head. The retaining elements 7 can be electrically contacted from below with conventional 4 mm laboratory plugs. The head shape of the retaining elements is arbitrary, but can have a slot for a screwdriver. The small number of parts allows very easy assembly, both under normal conditions and inside a glovebox with only limited room for movement.
[0053] FIG. 4 shows a further embodiment of a cell body half 1. This cell body half 1 can be regarded, for example, as the upper cell body half 1 of an arrangement of two cell body halves 1. Like the lower cell body half 1, the upper cell body half 1 has holes 5 which can be used to connect the two cell body halves 1. The cell body 2 itself is made of plastic material. Individual contact elements 4 are shown at the head of the retaining elements (not shown). Also in this embodiment of the upper cell body half 1, four contact elements 4 are shown as an example. However, the different cell body halves 1 can have different numbers of contact elements 4 and thus also retaining elements 7. For example, it is possible for the upper cell body half 1 to have only one contact element 4. Like the lower cell body half 1, the upper cell body half 1 has a recess 3 in which the actual measuring cell can be placed during measurement.
[0054] FIG. 5 shows a top view of a cell body half 1, in this case an upper cell body half 1. In this top view, the actual cell body 2, the bores 5, the receiving space 3 and the contact elements 4 can be seen. In this embodiment, there are four individual contact elements 4 in the receiving space 3. It can also be seen that each cell body half 1 does not necessarily have to have a sealing ring groove.
[0055] FIG. 6 shows a possible design of an upper cell body half 1 in a view from below. The actual cell body 2 is visible, in which the four retaining elements 7 are embedded. In addition, this view also shows the holes 5 through which the two cell body halves 1 can be connected to each other by means of screws.
[0056] FIG. 7 shows a cross-section of an embodiment of a lower cell body half 1. The retaining elements 7 can be seen extending through the cell body 2. The retaining elements 7 are hollow and can, for example, accommodate a plug for electrical contacting. Contact elements (not shown) can be attached to the tip of each of the retaining elements 7. Together with the contact elements, the retaining elements 7 connect one side of the cell body to the receiving space 3. Furthermore, recesses 6 are provided in the actual cell body 2, which can serve to receive a seal. Furthermore, a hole 5 is shown through which a screw can connect two halves of the cell body.
[0057] FIG. 8 shows a cross-section of an embodiment of an upper cell body half 1. The retaining elements 7 can be seen, which extend through the cell body 2. The retaining elements 7 are hollow and can, for example, accommodate a plug for electrical contacting. Contact elements (not shown) can be attached to the tip of each of the retaining elements 7. Together with the contact elements, the retaining elements 7 connect one side of the cell body to the receiving space 3. Furthermore, recesses 6 are provided in the actual cell body 2, which can serve to receive a seal. Furthermore, a hole 5 is shown through which a screw can connect two halves of the cell body.
[0058] FIG. 9 shows a top view of an embodiment of a receptacle 3 of a cell body half 1 with four different contact elements 4. The contact elements 4 can be, for example, contact elements 4 made of copper, platinum, nickel and iron and serve as measuring points in a single assembly of the cells one after the other or simultaneously. Compared to microcontacts, which are pressed against the sample with a spring over a small area, this allows a reduced risk of short-circuits, since the pressure applied to the sample is distributed more evenly.
[0059] FIGS. 10 and 11 show schematic views of current collector 8 (below). The current collector 8 can be annular in shape and minimally smaller than the diameter of the receiving space 3 (e.g. 0.1 mm) to allow easy sliding within the receiving space 3. This represents a major advantage of this design, per an embodiment. A fixed cell design can be used, in which any current collectors 8 of different construction can be used. FIG. 10 shows that the current collector 8 can have recesses 9 on its surface, which can be filled with an electrode material of the battery cell to be measured. In the FIG. 10, the current collector 8 is shown without further filling with electrode material. In the FIG. 11, the same embodiment is shown with the recesses of the current collector 8 filled with, for example, lithium metal 10. This results in two concentric areas on the current collector, which are separated by a non-conductive, central area.
[0060] FIG. 12 shows a further embodiment of a current collector 8 in plan view (top). This current collector 8 has no recesses on the surface. The inner circle of the current collector 8 indicates that this current collector is made of two different materials. For example, the inner area may be made of stainless steel and the outer area may be made of a non-conductive plastic material.
[0061] FIGS. 13 and 14 show possible designs of current collectors 8 in a sectional view. FIG. 13 shows, for example, an embodiment for an upper current collector 8. This current collector 8 does not have any recesses in the surface and is also not designed to receive electrode material of the battery cell to be measured. The inner portion 11 is made of stainless steel, whereas the two outer portions 12 may be made of a plastic material. The upper current collector 8 has a cylindrical shape, with the cylinder corners being rounded. FIG. 14 shows a cross-section of a possible lower current collector 8. Here, the lower current collector 8 may represent a cylinder with straight edges. This serves to ensure that the lower current collector 8 is pressed uni-axially upwards by the spring contacts, whereas the upper current collector 8 has increased flexibility within the housing due to the rounded edges and can, for example, be pressed more evenly against any sample surface by four contact elements 4. This is important, for example, for brittle ceramic solid electrolyte disks or pressed sulfidic tablets, as it allows the advantage of a reproducible internal pressure, which is independent of the external screw connection, per certain embodiments. The latter is the case, for example, with Swagelok T-cells. In this context, the exchange of these current collector 8 between top and bottom, as well as a combination of two rounded or two non-rounded current collectors 8 is possible.
[0062] FIGS. 14 and 15 show possible embodiments of a lower current collector 8 with a recess on the surface of the current collector 8. Parts of the electrodes of the battery cell can be embedded in the recesses of the current collector 8. With these electrode components, a flat surface is obtained for the current collector 8. Furthermore, it can be seen in the figure that the current collector 8 has a cylindrical shape and is made of different materials. In this respect, the current collector 8 can comprise areas which are formed from stainless steel 11 or from a plastic material 12. By the choice of the conductive areas, the contacting to the contact elements 4 (not shown) is established. This design of the current collectors 8 is so flexible that they can in principle also be used as current collectors for other cell types, such as Swagelok T-cells. These improve the basic principle of these T cells, per an embodiment, since the reference electrode now no longer has to be attached at right angles. In addition, the same advantages arise in principle as for the structure, for example in terms of improved pressure distribution.
[0063] FIG. 16 shows a further embodiment for a current collector 8. This embodiment is suitable, for example, for measuring battery cells with a structure with four contact elements 4 (not shown).
[0064] FIG. 17 shows a measurement curve obtained using the cell design. It shows the voltage behavior of a secondary lithium battery cell as a function of the specific capacitance within a cycle experiment. The battery cell is of the following construction. Cell body parts from FIGS. 1 and 3 were used, using an O-seal ring and gold-plated copper spring contacts with a spring constant of 1.5 N. The reference electrode and negative electrode were used as a function of the specific capacitance within a cycle experiment. The reference electrode and negative electrode were made of lithium and embedded in a current collector as shown in FIG. 11. NMC622 was used as the active material of the positive electrode and electrically contacted by means of a current collector as shown in FIG. 12. PEO-LiTFSI was used as separator and solid electrolyte. The cell was operated galvanostatically with a charge and discharge current of 15 mA g.sup.−1. The measurements are very reproducible and the proportion of measurement failures is extremely low.
[0065] All the features and advantages, including structural details, spatial arrangements and method steps, which follow from the claims, the description and the drawing can be fundamental to the invention both on their own and in different combinations. It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.
[0066] As used in this specification and claims, the terms “for example,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.
