JP2013543638A - Electrode manufacturing method - Google Patents

Abstract

  The electrode (1) for the electrochemical energy storage device has a contour (2) with two side edges, the first side edge (3) and the second side edge (4) being joined. They are joined together by part (5). The joint portion (5) includes a substantially straight region (5a) that transitions to the first side edge (3) and a substantially curved region (5b) that transitions to the second side edge (4). During the manufacture of such an electrode, the first side edge (3) is made by a first cut, the second side edge (4) is made by a second cut, and the joining part (5) is made by a first cut or Made with a second cut.

Description

  The present invention relates to a method for producing an electrode and an electrode produced by such a method, in particular an electrode for an electrochemical energy storage device.

  The development of electrochemical energy storage devices has received increasing attention recently. This is because these electrochemical energy storage devices are increasingly used for energy storage, for example in electrical goods, cars and power plants. As an electrochemical energy storage device has become a mass-produced product, its manufacturing process can become increasingly important in addition to its technical characteristics.

  In general, one electrochemical energy storage device comprises at least one electrochemical cell. The electrochemical cell includes a covering that defines an electrochemically active component from the periphery. This electrochemically active part of the cell, in particular in the case of a rectangular or coffee bag type energy storage cell, usually comprises a plurality of plate-like anodes, cathodes and separators, the anodes, cathodes and separators being , Alternately placed in contact with each other to form an electrode stack. The electrolyte is at least partially received in the separator.

  Collectively, the anode and cathode can be referred to as electrodes. In most cases, these electrodes are cut from a belt-like or plate-like semi-finished product. This cutting process is important during the manufacture of electrochemical energy storage devices based on multiple required electrodes.

  Known from the prior art is that the pointed corner of a sheet or similar semi-finished product has a radius, preferably as the pointed corner, preferably from the first cutting edge to the second cutting edge. An acute angle transition to can be understood. The corner area or edge area is often compromised by its geometric shaping, often by external and / or thermal loads. By applying a radius to these endangered parts, the load can be reduced. Furthermore, the risk of cracking and / or abrasion of the cell covering that is in contact can be reduced, thereby increasing the durability of these components.

  Moreover, the storage capacity of the electrochemical energy storage device depends inter alia on the total area of the electrodes. In particular, two alternatives can be considered to increase this area. One may increase the number of electrodes in one cell for increased capacity, and the other may increase the area of each individual electrode.

  Tool that allows at least one first cut and a second cut that is almost independent to cut these electrodes in order to be able to adapt the size of the electrodes flexibly. Seems to be reasonable. With two cuts that are almost independent of one another, the contour of the electrode is formed with at least two cut edges that are almost independent of one another, preferably four cut edges in the case of a substantially rectangular electrode.

  It is an object of the present invention to provide an improved method and an improved electrode for manufacturing an electrode.

  This is achieved according to the invention by the teachings of the independent claims. Preferred further embodiments of the invention are the subject matter of the dependent claims.

  The electrode which concerns on this invention has an outline provided with two side edges, and the 1st side edge and the 2nd side edge are mutually joined by the junction part. The joint portion includes a substantially straight region that transitions to the first side edge and a substantially curved region that transitions to the second side edge. During the manufacture of such an electrode, the first side edge is made by a first cut, the second side edge is made by a second cut, and the junction is made by a first cut or a second cut.

  In the electrode according to the present invention, the joint portion between the two side edges of the electrode includes a straight portion and a curved portion. This can be achieved by ensuring that the edges or edge portions of the electrodes do not intersect acute angles. In other words, it is possible to avoid a corner having a sharp angle, that is, an internal angle of 90 degrees or less. As a result, the mechanical and thermal load of the electrode in the region of the joint portion can be reduced, and the risk that the contacting covering is damaged in the region of the joint portion can be reduced. As a result, for example, the durability of an electrochemical cell having such an electrode can be increased.

  An “electrochemical energy storage device” is to be understood in this case as various energy stores from which electrical energy can be extracted, in which case an electrochemical reaction takes place inside the energy store. The term includes all kinds of energy stores, in particular primary and secondary batteries and fuel cells. The electrochemical energy storage device comprises at least one electrochemical cell, preferably a plurality of electrochemical cells. The plurality of electrochemical cells may be connected in parallel to store a larger amount of charge, or may be connected in series to obtain a desired drive voltage, or between parallel and series connections. Combinations may be formed.

  An “electrochemical cell” can then be understood as a device that releases electrical energy, in which case the energy is stored in chemical form. In the case of a rechargeable secondary battery, the cell is also configured to receive electrical energy and convert it to chemical energy for storage. The structure of the electrochemical cell (ie especially the size and geometry) can be selected depending on the space available. Preferably, the electrochemical cell is formed in a substantially prismatic or cylindrical shape. Although the present invention can be used in an advantageous manner, particularly for electrochemical cells called pouch cells or coffee bag cells, the electrochemical cells of the present invention are not limited to such applications. . In this context, “electrode stack” is to be understood as a structure consisting of at least two electrodes and one electrolyte provided therebetween. The electrolyte may be partially received by the separator, where the separator separates the electrodes. Preferably, the electrode stack comprises a plurality of layers of electrodes and separators, and the electrodes of the same polarity are each preferably electrically joined together, in particular connected in parallel. The electrodes are formed, for example, in the form of a plate or foil, and are preferably provided substantially parallel to each other (prism-shaped energy storage cell). The electrode stack may be wound and may have a substantially cylindrical structure (cylindrical energy storage cell). The term “electrode stack” should also include such electrode windings. The electrode stack may comprise lithium or another alkali metal in ionic form.

  The term “electrode” should mean a substantially plate-like element made of a conductive material (preferably metal or metal alloy) within the framework of the present invention. The electrode thickness may in this case range from a foil thickness to a plate thickness of a few millimeters. The outline or the basic shape of the electrode is basically arbitrary. Preferably, the electrode has a substantially rectangular basic shape with four side edges that meet substantially at right angles to each other.

  The “contour” of an electrode can be understood as an electrode boundary, preferably a closed and circular electrode boundary. Preferably, the electrode outline comprises a substantially polygonal shape. More preferably, the contour of the electrode is determined by at least one first side edge and a second side edge, preferably two first side edges and two second side edges. Preferably the electrode contour comprises at least two straight sections.

  The term “junction” may be understood as a part of the contour of the electrode that joins the first side edge with the second side edge. Suitably the joining portion joins side edges that intersect at an angle of greater than 60 degrees, preferably greater than 80 degrees, and / or preferably less than 120 degrees, preferably less than 100 degrees, Particularly preferably, these side edges intersect at a substantially right angle.

  The term “semi-finished product” includes the shape of the raw material prior to completion that must be further processed to produce the product. The semi-finished products are preferably available in a belt-like or continuous shape, or in a plate-like or individual piece. In this case, the belt-shaped or plate-shaped semi-finished product can be understood as a semi-finished product that extends greatly in the first space direction and the second space direction as compared with its slight thickness. The thickness may in this case range from a foil thickness to a plate thickness of a few millimeters. In order to produce foil thickness electrodes, the thickness of the semi-finished product is preferably less than 1 mm, more preferably less than 0.3 mm, particularly preferably less than 0.15 mm, and / or It is larger than 0.05 mm, more preferably larger than 0.1 mm, particularly preferably larger than 0.125 mm.

  The term “cutting” is to be understood in this connection as any mechanical and non-mechanical separation method suitable for making electrodes with the desired contour from a belt-like or plate-like semi-finished product. It is. Such separation methods include in particular mechanical methods such as die cutting, cutting, sawing and the like, and non-mechanical methods such as laser cutting, water jet cutting and the like. The electrode contour is preferably produced by a plurality of cutting or cutting processes that form the side edges of the electrode contour and the junction. The cutting edge can then be understood as a suitably connected part of the separation line between the prepared semi-finished product and the electrode. Suitably, the cutting process results in at least one and preferably two cutting edges. Preferably, the cutting edges that occur in the cutting process are substantially parallel to each other.

  The “straight region” of the junction can be understood as the part of the contour of the electrode that does not have a curve. Preferably, the straight region is in contact with the curved region of the joint portion.

  The “curved region” of the joining part can be understood as the part of the contour of the electrode comprising a curve. The curve is preferably formed in a substantially convex shape. The curve is preferably provided continuously in the curved region of the joint. Preferably, the curved region of the joint portion is in contact with the second side edge of the electrode. More preferably, the curved region is in contact with the straight region of the joint portion.

  In a preferred embodiment, the curved region of the joining portion comprises a substantially circular extension. More preferably, this region preferably comprises a constant radius. Suitably, this radius is in the range between about 1 mm and about 10 mm, more preferably between about 2 mm and about 6 mm, particularly preferably about 3 mm. The described radius of magnitude reduces, on the one hand, the disadvantageous corner load on the electrode contour, and on the other hand the electrode area is kept relatively large by the curved region.

  In a preferred embodiment, the curved region of the junction can be described substantially by the opening angle. This opening angle is preferably greater than 30 degrees, more preferably greater than 40 degrees and / or preferably less than 60 degrees, more preferably less than 50 degrees, particularly preferably about 45 degrees. It is. What is achieved by the opening angle of the curved part with the described size is that the area of the electrode is kept relatively large by the joint part and the angular load is reduced.

  In a preferred embodiment, the curved region of the joint portion transitions to the second side edge of the electrode in a substantially tangential direction. Preferably, the curved region of the joint portion transitions in a tangential direction to a side edge portion where the straight region of the joint portion does not intersect. This tangential transition advantageously avoids discontinuities in the electrode contour, thereby reducing its load and providing an improved method for cutting out the electrode.

  In a preferred embodiment, the linear region of the joint is preferably greater than 15 degrees, more preferably greater than 25 degrees, and / or preferably less than 60 degrees, more preferably greater than 50 degrees. Is also small and particularly preferably intersects the first side edge of the electrode at an angle of about 45 degrees. What is achieved by an angle within the described angular range is that, on the one hand, the area of the electrode is reduced only slightly by the joint, and on the other hand, the transition from the straight region to the side edge of the joint The edge load at is still small.

  In a preferred embodiment, the curved region of the joint portion transitions to the straight region of the joint portion in a substantially tangential direction. In an advantageous manner, this tangential transition causes a discontinuity in the electrode contour, which will negatively affect the loading of the electrode or the durability of the cell cladding in contact, between the two regions of the joint. It is avoided that this occurs at the transition part.

  In a preferred embodiment, the electrode comprises a generally rectangular shape. More preferably, each two side edges are joined to each other by joints constructed according to the invention. Preferably, the electrode comprises four joint parts, all the side edges being joined to each other via these. By constructing the electrode in this way, the electrode has a contour that is durable against external loads in the region and has a relatively large area. Thereby, by constructing the electrode as described, an electrode is provided that is suitably large and preferably durable. In addition, this electrode advantageously reduces the risk of damaging the contacting cell covering, for example at sharp edges or corners.

  Further features, advantages and applicability of the present invention result from the following description in connection with the accompanying figures. The following is shown in the figure.

First and second cutting of a belt-like semi-finished product for manufacturing an electrode according to the invention. It is a schematic fragmentary view for demonstrating the outline of the electrode in the area | region of the junction part between the two side edge parts of an electrode. FIG. 3 is a schematic partial view of an electrode stack.

  FIG. 1 shows a belt-like semi-finished product 8 that extends substantially in a first spatial direction 13 and a second spatial direction 14. The thickness of this semi-finished product (see FIG. 3 for this) is small compared to the first space direction 13 and the second space direction 14, for example only the thickness of the foil.

  Due to the first cutting process, this semi-finished product 8 is finally made with two first cutting edges which form the two first side edges 3 of the electrode 1, Thus, two second cutting edges are formed which form the two second side edges 4 of the electrode 1. In so doing, the second cutting process may be performed before the first cutting process. By these two cutting processes, the contour 2 of the electrode 1 is formed. The two cutting processes are preferably performed such that the electrode 1 is completely separated from the semi-finished product 8.

  In the embodiment of FIG. 1, the cutting edges 3 each extend over the entire width 14 of the semi-finished belt 8, but these cuts may be made shorter, and simply have about one more cutting edge 4. It may be carried out up to the area of the cutting point having. Depending on the type of cutting process, the time of the cutting process can be reduced in this way.

  FIG. 2 shows a joint portion 5 between the first side edge 3 and the second side edge 4 of the electrode 1. The joint portion 5 includes a straight region 5a and a curved region 5b. The straight region 5a has an (outer) angle 6 smaller than 90 degrees and transitions to the first side edge 3 of the electrode 1, while the curved region 5b is a second side edge in a substantially tangential direction. 4 In addition, the straight region 5a of the joint portion 5 has shifted to the curved region 5b in the substantially tangential direction. The names of the first side edge and the second side edge may be selectively reversed.

  The curved region 5 b of the joint portion 5 includes a substantially circular extending portion having a radius 9 and an opening angle 7. As specifically shown in FIG. 2, the straight region 5 a intersects the first side edge 3 at an angle 6.

  In the illustrated embodiment, the radius 9 of the curved region 5b of the joint portion 5 is about 4 mm, the opening angle 7 of the curved region 5b of the joint portion 5 is about 45 degrees, and the straight region 5a of the joint portion 5 is The cutting angle 6 between the first side edge 3 of the electrode 1 is about 45 degrees, but the present invention is not limited to these values.

  Compared to a simple rounding between the first side edge 3 and the second side edge 4 of the electrode 1, which can be described by a rounding radius 10, as specifically shown in FIG. By such a manufacturing method, the area of the electrode 1 is increased by the surplus area 11. The total area gain of the substantially rectangular electrode 1 is composed of a total of four such surplus areas 11, and the total area gain of the electrochemical energy storage cell is the plurality of surplus areas 11 of the plurality of electrodes 1. It is composed of A plurality of these surplus areas 11 can increase the capacity of the electrochemical energy storage device.

  FIG. 3 shows a fragment of an electrode stack, in which the electrode stack comprises a plurality of electrodes 1 and a plurality of separators 12 between the electrodes 1. The separator 12 is provided such that the two electrodes 1 are separated from each other by one of these separators 12. The electrode 1 substantially comprises a thickness 15 of a semi-finished product 8. Various electrodes 1 may be manufactured from different semi-finished products 8 and may be provided with different thicknesses 15 accordingly.

DESCRIPTION OF SYMBOLS 1 Electrode 2 Electrode outline 3 1st side edge part 4 2nd side edge part 5 Joining part 5a Straight line area | region 5b Joining part curved area 6 Cutting angle 7 Opening angle 8 Semi-finished product 9 Radius 10 of curved area 5b 10 Roundness Radius 11 Surplus area 12 Separator 13 First spatial direction 14 Second spatial direction 15 Semi-finished product or electrode thickness

Claims (14)

Comprising two side edges, wherein the first side edge (3) and the second side edge (4) have a contour (2) joined together by a joint part (5), in particular electrochemical For manufacturing an electrode (1) for a mechanical energy storage device from a belt-like or plate-like semi-finished product (8), wherein the first side edge (3) is made by a first cutting. The second side edge (4) is made by a second cut,
The joint portion (5) includes a substantially straight region (5a) and a substantially curved region (5b),
Method according to claim 1, characterized in that the joining part (5) is made by a first cut or a second cut.   The method according to claim 1, characterized in that the curved region (5b) of the joining part (5) comprises a substantially circular extension.   The radius (9) of the curved region (5b) of the joint portion (5) is in the range of about 1 mm to about 10 mm, more preferably in the range of about 2 mm to about 6 mm, particularly preferably about 3 mm. The method according to claim 2.   The curved region (5b) of the joint portion (5) has an opening angle within a range of about 30 degrees to about 60 degrees, more preferably within a range of about 40 degrees to about 50 degrees, and particularly preferably about 45 degrees. 4. The method according to any one of claims 1 to 3, comprising:   5. The curved region (5b) of the joint portion (5) transitions to the second side edge (4) of the electrode (1) in a substantially tangential direction. The method according to one item.   The straight region (5a) of the joint portion (5) has an angle (6) in the range of about 15 degrees to about 60 degrees, more preferably in the range of about 25 degrees to about 50 degrees, particularly preferably about 45 degrees. ) Intersecting the first side edge (3) of the electrode (1).   7. The curved region (5b) of the joint part (5) shifts to the linear region (5a) of the joint part (5) in a substantially tangential direction. The method described in 1. Comprising two side edges, wherein the first side edge (3) and the second side edge (4) have a contour (2) joined together by a joint part (5), in particular electrochemical In an electrode (1) for an active energy storage device,
The joint portion (5) includes a substantially straight region (5a) that transitions to the first side edge (3) and a substantially curved region (5b) that transitions to the second side edge (4). An electrode comprising the electrode.   The electrode (1) has a substantially rectangular shape with a total of four side edges, each of which has two side edges (3, 4) joined to a joint part (5) according to claim 8. The electrode according to claim 8, wherein the electrode is provided.   The curved region (5b) of the joint portion (5) comprises a substantially circular extension, and the radius (9) of the curved region (5b) is preferably in the range of about 1 mm to about 10 mm, more preferably. 10. An electrode according to claim 8 or 9, characterized in that is in the range of about 2 mm to about 6 mm, particularly preferably about 4 mm.   The curved region (5b) of the joint portion (5) has an opening angle within a range of about 30 degrees to about 60 degrees, more preferably within a range of about 40 degrees to about 50 degrees, and particularly preferably about 45 degrees. The electrode according to claim 8, wherein the electrode is provided.   The straight region (5a) of the joint portion (5) has an angle (6) in the range of about 15 degrees to about 60 degrees, more preferably in the range of about 25 degrees to about 50 degrees, particularly preferably about 45 degrees. The electrode according to any one of claims 8 to 11, wherein the electrode intersects the first side edge (3).   13. The curved region (5b) of the joint portion (5) shifts to the straight region (5a) of the joint portion (5) in a substantially tangential direction. Electrode.   Electrochemical cell comprising at least one electrode (1) according to any one of claims 8 to 13.

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