DE102012209727A1 - Electrochemical energy storage cell and method for producing an electrochemical energy storage cell - Google Patents

Abstract

The invention relates to an electrochemical energy storage cell (200), wherein the energy storage cell (200) has a winding (100) with at least two flat electrodes (110, 120) wound together, which are separated from one another by at least one separator element (130). 100) has a height (M) in the direction of a winding axis (140) which is smaller than at least one width (D, L1) of an end face (160) of the roll (100), wherein the winding axis (140) of the roll (100 ) is aligned within a tolerance range perpendicular to the end face (160). Furthermore, the electrochemical energy storage cell (200) comprises an electrode connection contact (210), which electrically contacts at least one of the electrodes (110, 120) from the end face (160).

Description

State of the art

The present invention relates to an electrochemical energy storage cell and a method for producing an electrochemical energy storage cell.

Climatic conditions or rapid charging and discharging often make it necessary to temper lithium-ion batteries. The current cell construction and the current cell design according to the prior art are not optimized for the removal and supply of heat. The structure of current winding cells is usually characterized in that the windings have a very long (rod) shape (comparable to the type 18650), which can sometimes cause a lot of heat during loading and unloading, which should be dissipated to damage to avoid the cells. Such an elongated structure therefore proves rather disadvantageous.

Disclosure of the invention

Against this background, the present invention provides an electrochemical energy storage cell and a method for producing an electrochemical energy storage cell according to the main claims. Advantageous embodiments emerge from the respective subclaims and the following description.

• – einen Wickel aus zumindest zwei zusammengewickelten flächigen Elektroden, die durch zumindest ein Separatorelement voneinander getrennt sind, wobei der Wickel eine Höhe in Richtung einer Wickelachse aufweist, die geringer ist, als zumindest eine Breite einer Stirnseite des Wickels, wobei die Wickelachse des Wickels innerhalb eines Toleranzbereichs senkrecht zur Stirnseite ausgerichtet ist; und
• – einen Elektrodenanschlusskontakt, der zumindest eine der Elektroden von der Stirnseite aus elektrisch kontaktiert.

The present invention provides an electrochemical energy storage cell for storing electrical energy, the energy storage cell having the following features:

• A reel of at least two coiled flat electrodes separated by at least one separator element, the reel having a height in the direction of a winding axis which is less than at least one width of an end face of the reel, the winding axis of the reel being within a Tolerance range is aligned perpendicular to the front side; and
• - An electrode terminal contact, the at least one of the electrodes electrically contacted from the front side.

• – Bereitstellen eines Wickels mit zumindest zwei zusammengewickelten flächigen Elektroden, die durch zumindest ein Separatorelement voneinander getrennt sind, wobei der Wickel eine Höhe in Richtung einer Wickelachse aufweist, die geringer ist, als zumindest eine Breite einer Stirnseite des Wickels, wobei die Wickelachse des Wickels innerhalb eines Toleranzbereichs senkrecht zur Stirnseite ausgerichtet ist; und
• – Elektrisch leitfähiges Kontaktieren zumindest einer der Elektroden mittels eines Elektrodenanschlusskontakts von der Stirnseite aus.

Furthermore, the present invention also provides a method for producing an electrochemical energy storage cell, the method comprising the following steps:

• - Providing a roll having at least two coiled flat electrodes, which are separated by at least one Separatorelement, wherein the winding has a height in the direction of a winding axis, which is less than at least one width of an end side of the coil, wherein the winding axis of the coil within a tolerance range is aligned perpendicular to the front side; and
• - Electrically conductive contacting at least one of the electrodes by means of an electrode connection contact from the front side.

A winding can be understood as a composite of coiled-up, for example, foil-like electrodes, which are electrically insulated from one another by a separator. In this case, the separator may also comprise an electrolyte or consist of such an electrolyte. By a winding axis, for example, a virtual axis can be understood, around which the electrodes are wound to form the winding. A height of the coil is to be understood as meaning a height of a lateral surface of the coil, which is measured in the extension direction of the winding axis. An end face of the reel is to be understood as meaning a (cross-sectional) surface of the reel which is aligned within a tolerance range perpendicular to the winding axis. In this case, the winding axis can be aligned, for example within the tolerance range by a normal to the front page. Further, the tolerance range may be, for example, a deviation of up to 45 degrees from the direction of extension of the winding axis. From the end face of the coil, for example, a spiral arrangement or a winding course of the composite of electrodes and separator is visible. A width of the coil at the end face may be, for example, a diameter of the end face of the coil in a cylindrical embodiment of the coil. Also, in the case of an oval or irregular roundish course of the front side, a width of the front side of the coil may be greater or longer than the (shell) height of the coil. An electrode connection contact may be understood to mean an electrical connection element for the electrically conductive contacting of at least one of the electrodes. The electrode connection contact may be an electrical conductor. In this case, the electrical conductor or the electrode connection contact should also be designed to absorb heat from the winding and dissipate it from the winding, or to introduce heat into the winding.

De present invention is based on the finding that by the electrical contacting at least one of the electrodes of the coil from the front side and a good thermal connection of the coil can be achieved when the coil has a greater width than (mantle) height. In this way, over the wider and thus larger contact surface, which is located on the front side, a larger heat flow away from the winding or to the winding are made possible, as if the winding compared to its length, ie to his (coat) Height has a very narrow or small cross-section. In this case, a heat transport along the winding axis would have to run in a thin, ie no cross-sectional area of the cell, so that only a very small heat transfer capacity could be ensured in such a cell.

The present invention offers the advantage that, owing to the favorable choice of the geometric dimensions of the energy storage cell and a favorable electrical (and thermal) contacting of the electrodes of the energy storage cell, there is now a possibility of transmitting a large amount of heat between the electrode connection contact and at least one of the electrodes. In this way, a better active temperature control of the energy storage cell can be made possible, which also makes faster charging and discharging of the energy storage cell possible.

It is also favorable if, according to an embodiment of the present invention, the winding on the end face has a length which is less than the height. In this case, a length may be understood to mean a dimension of the end face which is measured in a direction which differs from a direction in which the width of the end face is measured. Such an embodiment of the present invention offers the advantage that a high heat transfer capability of the energy storage cell can be realized, in particular if the area of the front side deviates from a circular shape. This results from the fact that now a larger outer surface of the energy storage cell compared to a cylindrical energy storage cell can be realized and thus also a heat dissipation can be significantly increased not only on the front side, but also on the lateral surface.

According to a further embodiment of the present invention, the electrode connection contact may be electrically conductively connected to the relevant electrode at an edge arranged on the end side, in particular wherein an electrical connection contact between the electrode connection contact extends over at least half of an overall length of the edge of the relevant electrode on the end side in particular, wherein the electrical connection between the electrode terminal contact extends over the entire length of the edge of the respective electrode on the front side, so that the electrode terminal contact is electrically connected at the edge to the electrode. Such an embodiment of the present invention offers the advantage that the electrode is electrically contacted with the electrode connection contact over a very large area of its edge on the front side, so that very low current densities are produced during operation of the energy storage cell at the transition between the electrode connection contact and the relevant electrode On the other hand, by a large contact area, there is also a high heat transfer capability between the electrode terminal contact and the subject electrode.

Also, according to a further embodiment of the present invention, the electrode terminal contact cover at least half of the edge or the entire edge length at the end side of the coil. Such an embodiment of the present invention offers the advantage that a large proportion of the area of the end face is covered by the electrode connection contact and, in a favorable manner, is also electrically and / or thermally connected to the electrode connection contact. On the one hand, this offers the possibility of making electrical contact with the relevant electrode causing only low current densities and, on the other hand, a very high ability to transfer heat between the electrode terminal contact and at least one of the electrodes can be achieved.

An embodiment of the present invention in which the electrode connection contact contains aluminum and / or copper or is made of aluminum and / or copper is particularly favorable. Such an embodiment of the present invention offers the advantage of a particularly high thermal conductivity and at the same time a high electrical conductivity, so that heat to be carried into the winding or out of the winding can be transported very well via the electrode connection contact and at the same time by an electric current flow into the electrode connection contact there is no danger of excessive heating in this connection contact.

In order to ensure the highest possible heat transfer from the winding or into the winding and at the same time the best possible electrical connection of both electrodes, according to a further embodiment of the present invention, the second of the electrodes from a second end face of the winding opposite the end face by means of a second Electrode contact terminal to be electrically contacted.

It is also advantageous if, according to one embodiment of the present invention, the electrode connection contact is formed spirally and arranged on the end face of the coil. Such an embodiment of the present invention has the advantage that a second of the electrodes can be electrically contacted from the front side, in which case, in particular, a spirally formed terminal contact can be used which is between the individual Spiral turns of the (first) electrode connection contact is arranged.

Furthermore, according to another embodiment of the present invention, the electrode terminal contact may also have a location at which it has a width that corresponds to at least one tenth of a width of the coil. Such an embodiment of the present invention ensures that a sufficiently high ability to dissipate or supply heat via the electrode terminal contact is possible. At the same time it can be ensured that a sufficient line cross-section is present in the electrode connection contact in order to be able to conduct high voltages or currents to the relevant electrode without the electrode connection contact being excessively heated.

• – einer ersten elektrochemischen Energiespeicherzelle gemäß einer in dieser Beschreibung vorgestellten Variante; und
• – einer zweiten elektrochemischen Energiespeicherzelle gemäß einer in dieser Beschreibung vorgestellten Variante, wobei der Elektrodenkontaktanschluss der ersten elektrochemischen Energiespeicherzelle mit dem Elektrodenkontaktanschluss der zweiten elektrochemischen Energiespeicherzelle elektrisch leitfähig verbunden ist.

Also particularly advantageous is an electrochemical energy storage unit having the following features:

• A first electrochemical energy storage cell according to a variant presented in this description; and
• - A second electrochemical energy storage cell according to a variant presented in this description, wherein the electrode contact terminal of the first electrochemical energy storage cell is electrically conductively connected to the electrode contact terminal of the second electrochemical energy storage cell.

In this way, a particularly powerful electrochemical energy storage unit can be provided.

The invention will now be described by way of example with reference to the accompanying drawings. Show it:

1 a perspective schematic diagram of a structure of a coil for an electrochemical energy storage according to an embodiment of the present invention;

2 a schematic representation of an electrochemical energy storage cell according to an embodiment of the present invention in an exploded view;

3 shows a perspective view of another possible form of the coil of the electrochemical energy store according to an embodiment of the present invention;

4 a representation of a heat flow from a winding of the electrochemical energy storage cell according to an embodiment of the present invention; and

5 a flowchart of an embodiment of the present invention as a method.

In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similarly acting, wherein a repeated description of these elements is omitted.

1 shows a perspective schematic representation of a structure of a coil 100 for an electrochemical energy store according to an embodiment of the present invention. The wrap 100 consists of at least a first electrode 110 and a second electrode 120 , which are formed for example as flat electrodes or as foil electrodes. The electrodes 110 respectively. 120 can be formed by a thin metal layer or contain such and by a separator 130 separated from each other, for example, be electrically isolated. The separator 130 can also be a planar component and, for example, have an electrically insulating material or an electrolyte. A composite 135 from the first electrode 110 , the separator 130 and the second electrode 120 can be around winding axis 140 rolled up to the wrap 100 to build. In the 1 is merely a schematic representation of the structure of the coil 100 with a winding of the composite 135 shown, of course, more windings in the winding 100 can be present, leaving a wrap 100 without cavity around the angle axis 140 can be realized. The first electrode 110 as well as the second electrode 120 indicate an in 1 above end one edge each 150 on, after making the angle 100 that is, after winding up the composite 135 around the angle axis 140 , on one end 160 of the roll 100 exposed. The front side 160 is one side of the roll 100 that are substantially perpendicular to the winding axis 140 is aligned, in particular wherein the winding axis is a normal to the front side 160 educated. At least the front should be 160 but within a tolerance range of, for example, 45 degrees perpendicular to the winding axis 140 be aligned.

2 shows a schematic diagram of an electrochemical energy storage cell 200 according to an embodiment of the present invention as an exploded view. Of the 2 is the wrap 100 shown only schematically as a cylindrical block with concentric circles, the concentric circles for ease of illustration half the individual windings of the coil 100 should represent. Out 2 It can be seen that a height M, which is a mantle height of the cylindrical illustrated winding 100 corresponds to, is less than a width D of the front side 160 that when choosing a coil 100 in the form of a cylinder, a diameter of the front side 160 equivalent. The wrap 100 has thus substantially the shape of a flat disc, which has a larger diameter, that is, a larger width D of the front side 160 , as having a height M. At the front 160 will now be the edge 150 one of the electrodes is electrically conductive with an electrode connection contact 210 connected so that the electrode in question, over the edge 150 with the electrode connection contact 210 connected via the electrode connection contact 210 can be acted upon by electrical voltage or electric current. In this case, the electrode connection contact 210 consist of aluminum or copper or contain such a material, so that on the one hand has a low electrical resistance and on the other hand, a high thermal conductivity.

By such a configuration of an electrochemical energy storage cell 200 it is now possible, the individual electrode layers or at least one of the electrode layers via the electrode connection contact 210 to apply electrical voltage or electric current, wherein in the energy storage cell 200 forming heat due to the low height M of the coil 100 also quickly over the edge again 150 and the electrode terminal contact can be discharged. This results from the fact that inside the energy storage cell 200 resulting heat only a very short way to the electrode connection contact 210 must be routed to over the electrode connection contact 210 from the energy storage cell 200 can be dissipated. This should be the largest possible area of the edge 150 Conveniently more than half the total length of the edge 150 of the relevant electrode, in contact with the electrode connection contact 210 be on the one hand a large heat transfer surface to dissipate heat from the winding 100 on the other hand, when the electrode is exposed to electric current at the edge 150 to cause only a low current density, and so an undesirable heating of the respective electrode over the edge 150 to avoid.

Of course, also a warming of the coil 100 take place via the electrode connection contact, for example, in which the electrode connection contact 210 itself is heated and the heat below over the front page 160 and the edge 150 into the with the electrode connection contact 210 connected electrode can be initiated.

To get the largest possible heat transfer surface on the front side 160 The electrode connection contact should also be ensured 210 Conveniently over at least half of the front page 160 extend or the relevant electrode, which with the electrode terminal contact 110 is connected, at least over a region of the front side 160 contact electrically, half of the area of the front side 160 equivalent. Furthermore, the electrode connection contact should also be 210 at least in one subarea 220 have a cross-sectional area Q which is one tenth of the area of the end face 160 equivalent. In this way it can be ensured that both a sufficiently low current density and a sufficiently high heat transfer capability through the electrode terminal contact 210 is ensured. For even better heat dissipation of the coil 100 The other of the electrodes can be reached 110 respectively. 120 on one of the front side 160 opposite side 230 also be electrically and thermally contacted via a further electrode connection contact, said further electrode terminal contact in the 2 for reasons of clarity is not shown in detail. This way, both on the front page 160 as well as on the opposite side 230 Heat from the wrap 100 dissipated or in the wrap 100 can be introduced, in which case an even greater heat transfer capability can be realized, as only via the contact on one side as the front side 160 ,

Alternatively, it is also conceivable that the electrode connection contact 210 , unlike in the 1 shown formed in the form of a spiral to each only the edge 150 Contact one of the electrodes electrically and thermally. The further electrode connection contact could then likewise be in the form of a spiral and in each case between the spiral-shaped (first) electrode connection contact 210 engaging the second of the electrodes on its edge 150 contact electrically and thermally. That way, the wrap could be 100 alone over the front 160 that is, electrically and thermally contacted via a single side, possibly resulting in a small available space for the energy storage cell 200 beneficial effect.

By constructing the cell as described above, the heat transfer within a cell 200 and optimized to the outside and their surface over which a more effective heat exchange with the environment can take place is increased. The heat supply at extremely low temperatures and the heat dissipation during fast charging or discharging operations become more effective, thereby further increasing the performance of the multiple by such cells 200 built-up batteries possible. A fast and homogeneous temperature control of the cell is made possible.

The arresters 210 (For example, which may contain or consist of aluminum and copper) of cathode and anode are also very good thermal conductors. They are arranged, for example, according to the approach presented here so that over this (over the known cell structure) faster and more heat off / can be supplied.

An important aspect of the present invention may be in an advantageous cell structure of the electrochemical energy storage cell 200 be seen. For example, as with respect to the 2 described a cylindrical cell 200 be constructed such that by the winding of the composite 135 resulting diameter D is greater than the cylinder height (M) of the coil 100 ,

In the choice of energy storage cell 200 in the form of a flat-wound cell, as in the 3 as a perspective view of another possible form of the coil 100 of the electrochemical energy storage device, the maximum diameter L1 (or a maximum extent) of the end face created by the winding should be 160 greater than the shell height M (defined by the width (or height) of the electrode.) It is also conceivable that another dimension L2 (for example, a length of the cross-sectional area 160 of the roll 100 may be smaller than the height of the coil or the width of the (wound) electrodes. In this case, a ratio L2 <M <L1 would be realized, in any case, that the height M of the coil 100 smaller than the maximum length L1. For Z-folding cells, the above principle applies analogously; This principle of electrical and thermal connection of the electrodes also applies to stacked cells.

The electrical connection is preferably predominantly on the end face; This allows a maximum ratio of contacted edge length 150 can be achieved to coated electrode surface. This causes high local currents in the arrester 210 avoided. The arrester layer thickness can be reduced (ie, cross section remains the same) or the cell 200 can be operated at higher C rates. Through the design presented herein, heat dissipation from the interior of the cell to the outside is provided by the shortest path within a layer without heat transfer between different layers / materials (eg, a trap-active layer separator sequence).

The approach presented here has several advantages. For example, a better heat supply / removal is feasible. Also is a homogeneous transport of heat 400 over front side 160 possible, as shown schematically in the 4 is shown. A cell constructed according to the approach proposed here 200 Furthermore, it is also easy to cool or temper, even in the case of a pack of several such cells. At the same time, short distances are possible from the arrester 210 into the active layer, ie the composite 135 from the electrodes 110 and 120 and the separator 130 realize what an advantage for tempering and current flow means. Also occur only low local currents in the arrester 210 on and an active temperature control is better possible than in the prior art. The approach proposed here shows a particular suitability for high-performance cells (which have high C rates), in particular the faster-charging and discharging and faster forming of the cells is made possible by the approach proposed here. Also, in a production of such a cell, a faster wettability of the separator can be carried out with electrolyte, since only short flow paths are to be overcome along the electrode surfaces. This saves production time and increases the production quality of such cells 200 ,

The thermal conductivity of copper and / or aluminum for the arrester 210 is still greater than that of the active materials (eg graphite) or the separator. In this way, heat can be transferred very quickly from the electrodes 110 respectively. 120 to the arrester 210 be guided and derived there. In addition, mass transfer (eg arrester-active-layer-separator-electrolyte) is disadvantageous for the heat transfer.

Within a cell, the heat conduction can thus be unimpeded in the direction of the end face (that is to say in the electrode plane), depending on the material and its specific thermal conductivity. In the stacking direction (i.e., perpendicular to the electrodes) over the electrode surfaces, good (metallic arresters) and poor (active material, separator) thermally conductive materials alternate. The heat inflow / outflow is thereby impeded.

The approach proposed here allows a cell structure to be designed for optimized thermal management (eg as an "enabler" for high-performance cells), for example as a lithium-ion battery. Such batteries made by the approach presented herein can be used in automotive applications, stationary energy storage, power tools, consumer electronics, or similar scenarios.

5 shows a flowchart of an embodiment of the present invention as a method 500 for producing an electrochemical energy storage cell. The procedure 500 comprises a step of providing 510 a reel having at least two coiled flat electrodes separated by at least one separator element, the reel having a height in the direction of a winding axis that is less than at least one width of an end face of the reel, the winding axis of the reel being within a tolerance range is aligned perpendicular to the front side. Furthermore, the method comprises 500 a step of electrically conductive contacting 520 at least one of the electrodes by means of an electrode connection contact from the front side.

The embodiments described and shown in the figures are chosen only by way of example. Different embodiments may be combined together or in relation to individual features. Also, an embodiment can be supplemented by features of another embodiment.

Furthermore, method steps according to the invention can be repeated as well as carried out in a sequence other than that described.

If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, then this is to be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment either only first feature or only the second feature.

Claims (10)

Electrochemical energy storage cell ( 200 ), wherein the energy storage cell ( 200 ) has the following features: a coil ( 100 ) with at least two flat electrodes ( 110 . 120 ) separated by at least one separator element ( 130 ) are separated from each other, wherein the winding ( 100 ) a height (M) in the direction of a winding axis ( 140 ), which is smaller than at least one width (D, L1) of a front side ( 160 ) of the roll ( 100 ), wherein the winding axis ( 140 ) of the roll ( 100 ) within a tolerance range perpendicular to the end face ( 160 ) is aligned; and - an electrode terminal contact ( 210 ), the at least one of the electrodes ( 110 . 120 ) from the front side ( 160 ) contacted from electrical. Electrochemical energy storage cell ( 200 ) according to claim 1, characterized in that the winding ( 100 ) on the front side ( 160 ) has a length (L2) which is less than the height (M). Electrochemical energy storage cell ( 200 ) according to one of the preceding claims, characterized in that the electrode connection contact ( 210 ) at one on the front side ( 160 ) arranged edge ( 150 ) with the relevant electrode ( 110 . 120 ) is electrically conductively connected, wherein an electrical connection between the electrode terminal contact ( 210 ) over at least half of an overall length of the edge ( 150 ) of the relevant electrode ( 110 . 120 ) on the front side ( 160 ), in particular wherein the electrical connection between the electrode terminal contact ( 210 ) over the total length of the edge ( 150 ) of the relevant electrode ( 110 . 120 ) on the front side ( 160 ) so that the electrode terminal contact ( 210 ) on the edge ( 150 ) with the electrode ( 110 . 120 ) is electrically connected. Electrochemical energy storage cell ( 200 ) according to one of the preceding claims, characterized in that the electrode connection contact ( 210 ) at least half of the edge ( 150 ) of the relevant electrode ( 110 . 120 ) on the front side ( 160 ) of the roll ( 100 ) covers. Electrochemical energy storage cell ( 200 ) according to one of the preceding claims, characterized in that the electrode connection contact ( 210 ) Aluminum and / or copper or is made of aluminum and / or copper. Electrochemical energy storage cell ( 200 ) according to one of the preceding claims, characterized in that the second of the electrodes ( 110 . 120 ) from one of the front side ( 160 ) opposite second end face ( 230 ) of the roll ( 100 ) is electrically contacted by means of a second electrode contact terminal. Electrochemical energy storage cell ( 200 ) according to one of the preceding claims, characterized in that the electrode connection contact ( 210 ) spirally formed and on the front side ( 160 ) of the roll ( 100 ) is arranged. Electrochemical energy storage cell ( 200 ) according to one of the preceding claims, characterized in that the electrode connection contact ( 210 ) an agency ( 220 ) at which it has a width (Q) which is at least one-tenth of a width (D, L1) of the roll ( 100 ) corresponds. Electrochemical energy storage unit having the following features: - at least one first electrochemical energy storage cell ( 200 ) according to one of the preceding claims; and at least one second electrochemical energy storage cell ( 200 ) according to one of the preceding claims, wherein the electrode contact connection ( 210 ) of the first electrochemical energy storage cell ( 200 ) with the electrode contact connection ( 210 ) of the second electrochemical Energy storage cell ( 200 ) is electrically conductively connected. Procedure ( 500 ) for producing an electrochemical energy storage cell ( 200 ), the process ( 500 ) comprises the following steps: - providing ( 510 ) of a coil having at least two coiled flat electrodes separated by at least one separator element, the coil having a height in the direction of a winding axis that is less than at least one width of an end side of the coil, the winding axis of the coil being within a Tolerance range is aligned perpendicular to the front side; and - Electric ( 520 ) conductive contacting at least one of the electrodes by means of an electrode connection contact from the front side.

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