Method for welding at least one cell component to electrode assembly of energy storage cell

Abstract

To provide an energy storage cell that improves thermoelectric properties, a manufacturing method of the same, and weld seam arrangement.SOLUTION: An energy storage cell 10 includes a step of placing at least one cell component 26 and arranging an electrode assembly 18 in contact with each other on the electrode assembly 18 of a super capacitor. Each cell component has an exposed weld accessible for welding by a welder. Each cell component 26 is welded to the electrode assembly by moving a welder relative to a weld surface 30 and forming a plurality of weld seams on the weld surface. At least two of the weld seams formed are selected from a group of weld seam types consisting of a transport weld seam 38 having a major directional component along a radial direction of the electrode assembly and a collector weld seam 39 having a major directional component along a circumferential direction of the electrode assembly.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for welding at least one cell component to an energy storage cell, preferably to an electrode assembly of a supercapacitor, and further to a weld seam arrangement obtained by welding, a method for manufacturing an energy storage cell, and an energy storage cell.

[0002] The energy storage cells described herein can be classified into three types: batteries, capacitors, and ultracapacitors (also called supercapacitors). As used herein, the term "battery" refers to an energy storage cell that stores electrical energy solely through electrochemical oxidation-reduction reactions. While "battery" typically includes primary batteries that can only be discharged, the term "battery" as used herein refers to secondary batteries, i.e., secondary batteries that can be charged and discharged.

[0003] As used herein, the term "capacitor" refers to an energy storage cell that stores electrical energy electrostatically. As used herein, the term "ultracapacitor" refers to a special type of capacitor, further categorized as a double-layer capacitor (DLC), a pseudocapacitor, and a hybrid capacitor. DLC stores energy electrostatically using a Helmholtz double layer. Pseudocapacitors store electrical energy electrochemically through faradaic electron charge transfer, such as intercalation or electrosorption. Hybrid capacitors utilize both DLC and pseudocapacitor mechanisms.

[0004] As electrification advances in many areas of life, ultracapacitors are becoming important in a variety of applications. They are easily rechargeable and can provide high peak power for short periods of time. As such, they are commonly sought after when high power demands that batteries cannot meet are needed. High peak power capability is typically achieved by having a low equivalent series resistance (ESR). Typically, ESR depends on the discharge rate; the faster the discharge rate, the higher the ESR, and vice versa. A lower ESR reduces the thermal load and potentially allows a larger portion of the electrical energy stored in the ultracapacitor to be extracted, meaning more energy can be utilized.

[0005] US 8 098 481 B2 discloses a method for manufacturing a double layer capacitor that achieves high operational reliability and improved power storage capacity while reducing manufacturing costs. In particular, the welding shape adopts a weld shape length, where the length of the start and end points of the weld seam is longer than the direct connection between these two points, i.e., the shape is other than a straight line.

[0006] EP 4 202 962 A1 discloses various types of weld seams. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to improve, in particular, the thermal, electrical and / or mechanical properties (i.e. at least one of these) of an ultracapacitor. This object is achieved by the subject matter of the independent claims. Preferred embodiments are the subject matter of the dependent claims. [Means for solving the problem]

[0008] The present invention provides a method for welding at least one cell component to an electrode assembly of an energy storage cell, preferably a supercapacitor, the method comprising:

[0009] - Placing each cell component and electrode assembly in contact with one another, where each cell component has an exposed welding surface accessible to welding equipment for welding.

[0010] - welding each cell component to the electrode assembly by moving a welding fixture relative to the welding surface to form a plurality of weld seams on the welding surface, wherein at least two of the formed weld seams are selected from the group of weld seam types consisting of:

[0011] - a transport weld seam having a main directional component along the radial direction of the electrode assembly;

[0012] - Collector weld seam with a main direction component along the circumferential direction of the electrode assembly.

[0013] Typically, the energy storage cells included in a module are interconnected via busbars. The busbars are typically connected to a central hub of the energy storage cells. The transport weld seams are typically oriented to transport current toward the central hub. The collector weld seams are typically oriented to collect current extracted from the more radially outward electrode assembly layers before being transported by the transport weld seams. For high power demands, i.e., high currents, the current is conducted with lower resistance, thereby reducing heat generation during charging and discharging.

[0014] Preferably, the transport weld seam has a first end point that is a greater distance from the circumferential surface of the electrode assembly than a second end point, and the second end point is a smaller distance from the circumferential surface. Preferably, the collector weld seam has a first end point and a second end point that are approximately the same distance from the circumferential surface. Preferably, this distance is measured along a radial direction. Preferably, the first end point and the second end point are spaced apart along a radial direction with multiple electrode layers between them. With this configuration, the transport weld seam is primarily oriented inward from the circumferential side, with current typically flowing across different layers of the electrode assembly. The collector weld seam is primarily oriented along a circumferential direction, with current primarily flowing along the same layer of the electrode assembly.

[0015] Preferably, the transport weld seam is formed as a straight line or a circular arc connecting the first end point and the second end point, respectively. Preferably, the collector weld seam is formed as a straight line or a circular arc connecting the first end point and the second end point, respectively. Simple geometric shapes such as straight lines and circular arcs can be easily formed by a welding tool.

[0016] Preferably, the electrode assembly is a wound electrode assembly including a plurality of electrode layers, the radial direction being substantially perpendicular to the electrode layers, and the circumferential direction being substantially tangential to the electrode layers. Preferably, the main current flowing through the transport weld seam flows parallel to the radial direction. Preferably, the main current flowing through the collector weld seam flows parallel to the circumferential direction. This allows current to be more efficiently collected toward the periphery of the electrode assembly and conducted toward the center by the transport weld seam, thereby reducing equivalent series resistance (ESR).

[0017] Preferably, the principal directional component is measured by projecting the straight-line distance between the first and second end points in a radial or circumferential direction.

[0018] Preferably, during welding, a plurality of separate transport weld seams are formed that are parallel to one another or that sandwich an acute angle. Preferably, during welding, a plurality of connected transport weld seams are formed that sandwich an acute angle, and the transport weld seams are connected at their end points.

[0019] Preferably, the individual separated transport weld seams and / or the connected transport weld seams include a first transport weld seam and a second transport weld seam arranged adjacent to each other along the circumferential direction. Preferably, a first end point of the first transport weld seam is at a greater distance from the outer periphery of the electrode assembly than a first end point of the second transport weld seam. Preferably, the first transport weld seam is longer than the second transport weld seam. Preferably, the second end points of the first transport weld seam and the second transport weld seam are at approximately the same distance from the outer periphery.

[0020] Preferably, during welding, at least one collector weld seam is formed and connected to at least one weld seam, and preferably each collector weld seam and each weld seam are connected at their respective end points.

[0021] Preferably, during welding, at least one collector weld seam is formed, which is connected to at least one transport weld seam and / or at least one collector weld seam, and preferably each collector weld seam is connected to a corresponding respective transport weld seam at their respective end points.

[0022] Preferably, during welding the weld seam is formed so that a closed contour is formed.

[0023] Preferably, the cell component is a current collector disk having a plurality of slits, preferably radial slits, and / or a central hole. Preferably, the welding surface is disposed on the collector disk, and its boundary includes two adjacent slits, a central hole, and / or an outer periphery of the current collector disk.

[0024] Preferably, the cell component is a current collector tab having a hub portion and a plurality of arms, preferably radial arms, extending therefrom toward the outer periphery of the electrode assembly. Preferably, the arms include at least one leg that is thicker than the remaining arms and parallel to the arms. Preferably, a welding surface is disposed on each arm, the boundary of which includes the hub portion and / or the legs.

[0025] Preferably, the cell component is a cell housing bottom of an energy storage cell. Preferably, the cell housing bottom has a plurality of grooves, preferably radial grooves, and / or a central hub. Preferably, the welding surface is disposed within the grooves and includes a sidewall of the groove as a boundary.

[0026] Preferably, each transport weld seam has a major directional component parallel to any of the slits, legs, and grooves. Preferably, each collector weld seam has a major directional component perpendicular to any of the slits, legs, and grooves.

[0027] Preferably, the cell component is the uppermost component and the transport weld seam, in top-down view, forms an angle α with respect to the normal to the layer of the electrode assembly in the range of 0°≦α≦45°, preferably in the range of α≦36°, preferably in the range of α≦25°, preferably in the range of α≦15°, preferably in the range of α≦10°, preferably in the range of α≦8°, preferably in the range of α≦6°, preferably in the range of α≦4°, preferably in the range of α≦3°, preferably in the range of α≦2°.

[0028] Preferably, the cell component is a bottom component, and in bottom view, the transport weld seam forms an angle α with respect to a normal to the layer of the electrode assembly in the range of 0°≦α≦15°, preferably in the range of α≦13°, preferably in the range of α≦8°, preferably in the range of α≦5°, preferably in the range of α≦2°.

[0029] The present invention provides a welded seam arrangement consisting solely of a welded seam obtained by welding according to a preferred method.

[0030] The present invention provides a method for manufacturing an energy storage cell, preferably a supercapacitor, comprising:

[0031] - Comprises a cell housing that is open at the top and closed at the bottom.

[0032] - Inserting the electrode assembly and / or at least one cell component into the cell housing.

[0033] - Performing a preferred method to weld the electrode assembly to the cell housing and / or at least one cell component.

[0034] - Wet the electrode assembly with electrolyte.

[0035] - Close the cell housing.

[0036] The present invention provides an energy storage cell obtained by the preferred method.

[0037] This invention is based on the discovery that in an energy storage cell, the weld seam connecting the current collector or cell housing to the wound electrode assembly has a significant impact on the thermal, electrical, and mechanical properties of the cell. In particular, the geometry of the weld seam can have a significant impact on both the thermoelectric and vibrational properties of the cell. For brevity, we will focus on the thermoelectric properties, since vibrational properties considerations can now be mitigated in a more convenient manner.

[0038] Although the ideas are described with reference to cylindrical cells, those skilled in the art will readily appreciate that the ideas presented herein may also be applied to prismatic cells, or more generally, to any cell type in which the electrode assembly is connected via a welded seam to a current collector within the cell housing or to the cell housing itself.

[0039] Typically, the weld seam extends radially outward from the center of the electrode assembly.

[0040] The goal is to find a shape for the weld seam that allows for improved thermoelectric properties, such as lowering the temperature generated during cell use and reducing the ESR (internal resistance).

[0041] In energy storage cells, the uncoated outer portion of the electrode assembly is typically beaded at the top and bottom of the assembly. The electrode assembly itself is typically a wound structure with two electrodes and a separator between them. Due to the nature of the wound structure, the outer periphery of the electrode assembly generally contains more active electrode material per volume than the more inwardly located portions.

[0042] In some embodiments, current collectors are disposed at the top and / or bottom of the electrode assembly, and can be metal disks, star tabs, or other shapes depending on the shape of the cell.

[0043] The connection between the electrode and the current collector is established by multiple weld seams, which can be spot welds or can be welded in the form of a straight line or arc.

[0044] It is proposed that the current collector be connected to the electrode assembly via a particular weld seam geometry that exhibits two important features.

[0045] The inner portion of the weld seam, which extends from the center of the electrode assembly to the outer periphery of the electrode assembly or vice versa, is called the transport path or transport weld seam.

[0046] The outer portion of the weld seam, which primarily covers the outer periphery of the electrode assembly, is called the collector pass or collector weld seam.

[0047] The transport path preferably covers a direction perpendicular or nearly perpendicular to the electrode layers of the electrode assembly. In top / bottom view, the transport path generally "crosses" the electrode layers.

[0048] The collector paths may be oriented more tangentially to the direction of the electrode layers. The angle between the collector paths and the direction of the winding electrodes is typically smaller than the angle between the transport paths and the direction of the winding electrodes.

[0049] For both the transport path and the collector path, there may be multiple subsections that differ from one another in direction and overall geometry.

[0050] In one weld seam there may be at least one or more transport channels and at least one or more collector channels.

[0051] In one embodiment, in addition to multiple weld seams, one or more line welds can also be added (i.e., weld seams extending from the periphery of the electrode assembly toward the center, or vice versa; these are weld seams that essentially constitute the transport path).

[0052] The technical advantage of the weld geometry presented herein is that it improves the thermoelectric properties of the energy storage cell or electrode assembly / current collector. This is typically due to the larger surface area covering the periphery of the electrode assembly. This allows for more efficient and less resistance conduction of higher currents, which occur toward the periphery relative to the center of the electrode assembly. In particular, the reduced ESR reduces the amount of heat generated during cell charging and discharging, leading to improved efficiency and longer life.

[0053] Embodiments of the present invention will now be described in more detail with reference to the accompanying schematic drawings listed below. [Brief explanation of the drawings]

[0054] [Figure 1] 1 shows a cross section of an energy storage cell. [Figure 2] 1-1 are diagrams of energy storage cells showing different embodiments of weld seam arrangements. [Figure 3] 1-2 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 4] 1-3 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 5] 1-4 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 6] 1-5 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 7]1-6 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 8] 1-7 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 9] 2-1 is a diagram of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 10] 2-2 are diagrams of energy storage cells showing different embodiments of weld seam arrangements. [Figure 11] 2-3 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 12] 2-4 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 13] 2-5 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 14] 2-6 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. [Figure 15] 2-7 are diagrams of an energy storage cell showing different embodiments of weld seam arrangements. DETAILED DESCRIPTION OF THE INVENTION

[0055] Referring to Figure 1, an energy storage cell 10 is shown being welded. The energy storage cell 10 includes a cell housing 12 (also called a casing or can) having an open top 14 and a closed bottom 16. The cell housing 12 is preferably cylindrically shaped.

[0056] The energy storage cell 10 includes an electrode assembly 18. The electrode assembly 18 includes, in a manner known per se, a plurality of electrode layers 20 (FIG. 2). The electrode layers 20 are composed of current collectors, separators, and active materials, and are wound together, shown as dotted circles for clarity. Note that in reality, the electrode layers 20 would be much thinner and would be spiral rather than concentric.

[0057] The electrode assembly 18 is welded to the closed base 16 and the current collector disk 22 or current collector tab 24. The closed base 16, the current collector disk 22, and the collector tab 24 are examples of cell components 26.

[0058] Example T1 2, a top view illustrates a weld seam arrangement 28 obtained by welding the electrode assembly 18 to the current collector disk 22. The current collector disk 22 includes a disk center 32, adjacent radial slits 34, and a weld surface 30 surrounded by a peripheral edge 36.

[0059] The weld seam arrangement 28 is formed by moving a welding tool of a welding machine (not shown) relative to the welding surface 30. The welding tool may be a laser system that applies a laser beam to the welding surface 30. An ultrasonic welding tool may also be used. Other welding methods are also possible.

[0060] The weld seam arrangement 28 includes a plurality of transport weld seams 38.1, ..., 38.5 (collectively referred to as 38), each extending radially toward the outer periphery 19 of the electrode assembly 18 between a first end point 40.1, ..., 40.5 and a second end point 42.1, ..., 42.5 (collectively referred to as 40 and 42, respectively).

[0061] The first endpoint 40 is farther from the outer periphery 19 than the second endpoint 42. As shown, the first endpoints 40 have different distances from the outer periphery 19, i.e., the first endpoint 40.3 is farthest from the outer periphery 19 along the radial direction.

[0062] The first end points 40.2 and 40.4 are preferably closest to the outer periphery 19 along the radial direction, but are more than halfway away from the outer periphery 19 along the radial direction.

[0063] The first end points 40.1 and 40.5 are radially disposed between the first end points 40.2 and 40.4 and the first end point 40.3, and preferably radially disposed near the first end point 40.3.

[0064] As shown, the transport weld seams 38 are formed as straight lines between respective first and second endpoints 40, 42. At least one pair of the transport weld seams 38 subtend an acute angle of 65° or less, preferably 60° or less, preferably 47° or less, preferably 33° or less, and preferably 17° or less.

[0065] At least one pair of circumferentially adjacent transport weld seams 38 form an acute angle of 20° or less, preferably 18° or less, and preferably 14° or less.

[0066] The transport weld seam 38 is positioned to intersect the electrode layer 20 substantially perpendicularly, such as with a maximum deviation of 2°.

[0067] The welding is performed by moving the welding tool in a linear fashion from a first endpoint 40.1 (indicated by a circular dot) to a second endpoint 42.1 (indicated by a small arrow), forming a linear transport weld seam 38.1. The welding is then interrupted, and the welding tool is moved to a second endpoint 42.2 where welding begins again. The welding tool is then moved in a linear fashion to the first endpoint 40.2, forming transport weld seam 38.2. This process is repeated until the remaining transport weld seams 38.3, ..., 38.5 are formed as shown.

[0068] This weld seam arrangement 28 may be repeated five more times along the circumferential direction with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disc center 32 and slits 34 are not covered by any of the weld seams.

[0069] Simulations by the inventors have shown that the steady-state ESR of this weld seam arrangement 28 is approximately 0.088 mΩ and that temperatures starting from 0°C and up to 34°C can be achieved during transient short circuit conditions.

[0070] A transient short-circuit condition is simulated by a current pulse with a predetermined maximum short-circuit current. It should be noted that this simulation is performed to benchmark various weld seam arrangements 28 based on steady-state ESR and maximum temperature. Therefore, the obtained values ​​do not necessarily reflect the parameters that will occur in a real application, but they are useful as a qualitative comparison. In other words, it can be reasonably assumed that a weld seam arrangement 28 that achieves a lower steady-state ESR and / or a lower maximum temperature in the simulation will also achieve a lower steady-state ESR (steady-state equivalent series resistance) and / or a lower maximum temperature in a real application, even if the simulated values ​​and the actual measured values ​​are completely different. And vice versa.

[0071] Example T3 3, a top view shows the weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process will be described only insofar as it differs from the previous embodiment.

[0072] The weld seam arrangement 28 includes a plurality of transport weld seams 38.1, ..., 38.7 (collectively referred to as 38), each extending radially toward the outer periphery 19 of the electrode assembly 18 between a first end point 40.1, ..., 40.7 and a second end point 42.1, ..., 42.7 (collectively referred to as 40 and 42, respectively).

[0073] The transport weld seams 38.1,..., 38.6 are directly connected to each other to form a continuous structure, while the transport weld seam 38.7 is independent (separated from the others).

[0074] First endpoint 40 is farther from outer periphery 19 than second endpoint 42. As shown, first endpoints 40 have different distances from outer periphery 19. That is, first endpoints 40.3 and 40.4 are radially farthest from outer periphery 19 and overlap / coincide.

[0075] The first end point 40.7 is located at a position radially closest to the outer periphery 19 and closer to the disc center 32 than the outer periphery 19.

[0076] The first end points 40.1, 40.2 and 40.5, 40.6 are radially disposed between the first end points 40.3 and 40.4 and the first end point 40.7, and preferably are radially disposed near the first end point 40.7.

[0077] As shown, the transport weld seams 38 are formed as straight lines between corresponding first and second end points 40 and 42. At least one pair of the transport weld seams 38 subtends an acute angle of 65° or less, preferably 58° or less, preferably 43° or less, preferably 33° or less, preferably 25° or less, and preferably 17° or less.

[0078] At least one pair of circumferentially adjacent transport weld seams 38 form an acute angle of 28° or less, preferably 15° or less, and more preferably 8° or less.

[0079] The transport weld seam 38 is oriented to intersect the electrode layer 20 approximately perpendicularly, with a maximum deviation of, for example, 8°.

[0080] Welding can be performed by starting the welding tool at second end point 42.1 and moving linearly to overlapping and coinciding first end points 40.1 and 40.2 to form linear transport weld seam 38.1. The welding tool then moves without interruption to overlapping and coinciding second end points 42.2 and 42.3 to form transport weld seam 38.2. This process is repeated until the remaining transport weld seams 38.3, ..., 38.6 are formed, as shown.

[0081] Finally, the weld breaks to form a separate (independent) transport weld seam 38.7.

[0082] This weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disk center 32 and slits 34 are not covered by any of the weld seams.

[0083] Simulations by the inventors have shown that the steady-state ESR of this weld seam arrangement 28 is approximately 0.088 mΩ and that temperatures starting from 0°C and up to 35°C can be obtained during transient short circuit conditions.

[0084] Example T6 4, a top view shows the weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process will be described insofar as it differs from the previously described embodiments.

[0085] The weld seam arrangement 28 includes a plurality of transport weld seams 38.1, ..., 38.6, collectively referred to as 38. The transport weld seams 38 extend radially toward the outer periphery 19 of the electrode assembly 18 between first end points 40.1, ..., 40.6 and second end points 42.1, ..., 42.6, collectively referred to as 40 and 42, respectively.

[0086] The transport weld seams 38.1, ..., 38.6 are directly connected to one another and form a continuous structure. The transport weld seams 38 form a closed contour on the weld surface 30.

[0087] The first endpoint 40 is farther from the outer periphery 19 than the second endpoint 42. As shown, the first endpoints 40 may have different distances from the outer periphery 19. That is, the first endpoints 40.1 and 40.6 are farthest from the outer periphery 19 along the radial direction and overlap / coincide.

[0088] The first end points 40.2, . . . , 40.5 are radially closest to the outer periphery 19 and are closer to the disc center 32 than the outer periphery 19.

[0089] The first end points 40.2, ..., 40.5 are arranged radially between the first end points 40.1 and 40.6 and the second end point 42, and preferably arranged radially closer to the first end points 40.1 and 40.6.

[0090] As shown, the transport weld seams 38 are formed as straight lines between respective first and second endpoints 40, 42. At least one pair of the transport weld seams 38 subtend an acute angle of 65° or less, preferably 60° or less, preferably 45° or less, preferably 25° or less, and preferably 17° or less.

[0091] At least one pair of circumferentially adjacent transport weld seams 38 subtend an acute angle of 63° or less, preferably 25° or less, and preferably 18° or less.

[0092] The transport weld seam 38 is oriented to intersect the electrode layer 20 approximately perpendicularly, for example with a maximum deviation of less than 45°, preferably less than 40°.

[0093] Welding can be performed by starting the welding tool at first end point 40.1 and moving linearly to overlapping and coinciding second end points 40.1 and 40.2 to form linear transport weld seam 38.1. The welding tool then moves without interruption to overlapping and coinciding first end points 40.2 and 40.3 to form transport weld seam 38.2. This process is repeated until the remaining transport weld seams 38.3, ..., 38.6 are formed, as shown. To avoid double welding to overlapping and coinciding first end point 40.1, welding is stopped just before first end point 40.6.

[0094] This weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disk center 32 and slits 34 are not covered by any of the weld seams.

[0095] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of approximately 0.093 mΩ and can achieve a maximum temperature of 74°C starting from 0°C during a transient short circuit condition.

[0096] Example T2 5, a top view shows the weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process will be described insofar as it differs from the previously described embodiments.

[0097] The weld seam arrangement 28 includes a plurality of collector weld seams 39.1, ..., 39.11 (collectively referred to as 39). The collector weld seams 39 extend primarily along a circumferential direction parallel to the outer periphery 19 of the electrode assembly 18 between first end points 40.1, ..., 40.11 and second end points 42.1, ..., 42.11 (collectively referred to as 40 and 42, respectively).

[0098] The collector weld seams 39.1,..., 39.11 are directly connected to one another and form a continuous structure.

[0099] The first and second endpoints 40, 42 of each collector weld seam are approximately the same distance from the outer periphery 19. As shown, the first and second endpoints 40, 42 are aligned radially in a linear pattern.

[0100] Except for the outermost collector weld seam 39.1 and the innermost collector weld seam 39.10, the first end point 40 and the second end point 42 of the collector weld seams 39 adjacent to each other in the radial direction overlap and coincide with each other.

[0101] As shown in the figure, a series of collector weld seams 39 are formed as straight lines connecting a first end point 40 and a second end point 42. At least one pair of collector weld seams 39 are preferably radially adjacent and form an acute angle of 45° or less, preferably 30° or less, preferably 25° or less, preferably 10° or less, and preferably 8° or less. Preferably, the angles between radially adjacent collector weld seams 39 are the same except for the innermost collector weld seams 39.9 and 39.10. Alternate collector weld seams 39 may be parallel to one another.

[0102] The collector weld seam 39 is oriented in the direction of a tangent at a point on the electrode layer 20 and extends with a main direction component parallel to the circumferential direction, for example with a maximum deviation of less than 45°, preferably less than 40°, preferably less than 30°.

[0103] Welding can be performed such that the welding tool starts at first end point 40.1 and moves linearly to overlapping and matching second end points 42.2 and 42.1 to form linear collector weld seam 39.1. The welding tool then moves without interruption to overlapping and matching first end points 40.2 and 40.3 to form collector weld seam 39.2. This process is repeated until the remaining collector weld seams 39.3, ..., 39.11 are formed, as shown.

[0104] This weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disk center 32 and slits 34 are not covered by any of the weld seams.

[0105] Simulations by the inventors have shown that the steady-state ESR of this weld seam arrangement 28 is approximately 0.088 mΩ and that temperatures starting from 0°C and up to 33°C can be obtained during transient short circuit conditions.

[0106] Example T5 6, a top view shows the weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process will be described insofar as it differs from the previously described embodiments.

[0107] The weld seam arrangement 28 comprises a plurality of transport weld seams 38.1, ..., 38.3 and a plurality of collector weld seams 39.1. The transport weld seams 38.1 and 38.2 are directly connected to each other and to the collector weld seam 39.1. The transport weld seams 38 and 39 form a continuous structure and a closed contour. The transport weld seam 38.3 is located outside this closed contour and extends radially.

[0108] First end points 40.1, 40.2 of transport weld seam 38 are located furthest from outer circumference 19. First end points 40.3 and second end points 42.3 of collector weld seam 39.1 are located the same radial distance from outer circumference 19. First end points 40.4 and second end points 42.4 of transport weld seam 38.3 are located the same radial distance from outer circumference 19 as are first and second end points 40, 42 of transport weld seams 38.1, 38.2 and collector weld seam 39.1, respectively.

[0109] As shown, the transport weld seam 38 and the collector weld seam 39 are formed as straight lines between respective first and second end points 40 and 42 .

[0110] The transport weld seams 38.1 and 38.2 subtend an acute angle of 35° or less, preferably 30° or less, preferably 20° or less.

[0111] The collector weld seam 39.1 and the directly connected transport weld seam 38.1 or 38.2 subtend an acute angle of less than 80°, preferably less than 75°, preferably less than 73°.

[0112] Welding can be performed by starting the welding tool at first end point 40.1 and moving linearly to overlapping first and second end points 42.1 and 40.3 to form linear transport weld seam 38.1. The welding tool then moves without interruption to overlapping second end points 42.2 and 42.3 to form collector weld seam 39.1. From there, the welding tool moves to overlapping first end points 40.1 and 40.2 to form transport weld seam 38.2.

[0113] Finally, a separate transport weld seam 38.3 can be formed. A triangular structure can be formed on the other side of the separate, independent transport weld seam 38.3 as well.

[0114] The entire weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disk center 32 and slits 34 are not covered by any of the weld seams.

[0115] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of approximately 0.085 mΩ and can achieve a maximum temperature of 24°C starting from 0°C during a transient short circuit condition.

[0116] Example T4 7, a top view shows the weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process is described insofar as it differs from Example T5.

[0117] The triangular structure is formed as described above, with the main difference being that the separate transport weld seam 38.3 is formed within a closed contour. The triangular structure is repeated in the same manner within the weld surface 30.

[0118] The entire weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disk center 32 and slits 34 are not covered by any of the weld seams.

[0119] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of about 0.085 mΩ and can achieve a maximum temperature of 22°C starting from 0°C during a transient short circuit condition.

[0120] Example T7 8, a top view shows the weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process will be described insofar as it differs from the previously described embodiments.

[0121] The weld seam arrangement 28 comprises a plurality of transport weld seams 38.1, ..., 38.3 and a plurality of collector weld seams 39.1 and 39.2. The transport weld seams 38.1 and 38.2 are directly connected to the collector weld seam 39.1 but not directly connected to each other. The transport weld seams 38 and 39 form a continuous structure but do not form a closed contour. The transport weld seam 38.1 is radially longer than the transport weld seam 38.2. The transport weld seam 38.3 is located next to it in the circumferential direction and is directly connected to the collector weld seam 39.2.

[0122] The transport weld seam 38 is formed in a straight line, whereas the collector weld seam 39 is formed in an arc, as in the embodiments T5 and T4.

[0123] The transport weld seams 38.1 and 38.2 subtend an acute angle of 35° or less, preferably 30° or less, preferably 20° or less.

[0124] The transport weld seam 38.1 or 38.2 together with the transport weld seam 38.3 enclose an acute angle of less than 35°, preferably less than 30°.

[0125] The collector weld seam 39.1 is tangentially continuous with the transport weld seams 38.1 and 38.2. In other words, the first point 40.3 and the last point 42.1 overlap each other without any twist or misalignment. The same is true for the collector weld seam 39.1 and the transport weld seam 38.3.

[0126] The weld can be performed by starting the welding tool at first end point 40.1 and moving in a straight line to overlapping first and second end points 42.1 and 40.3 to form a linear transport weld seam 38.1. The welding tool then moves uninterrupted along an arc to second end points 42.2 and 42.3 to form collector weld seam 39.1. From there, the welding tool moves to first end point 40.2 to form transport weld seam 38.2. This arrangement can be rearranged in a mirror image, as shown in FIG. 8.

[0127] Finally, the separate and isolated transport weld seam 38.3 and collector weld seam 39.2 can be formed in a similar manner.

[0128] The entire weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the disk center 32 and slits 34 are not covered by any of the weld seams.

[0129] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of about 0.087 mΩ and can achieve a maximum temperature of 31°C starting from 0°C during a transient short circuit condition.

[0130] Example B1 9, the figure illustrates a weld seam arrangement 28 obtained by welding the electrode assembly 18 to the current collector tab 24 or cell housing 12. The current collector tab 24 has a weld surface 30 bounded by a hub portion 132 and arms 134. The weld surface 30 is generally rectangular.

[0131] The weld seam arrangement 28 is formed by moving a welding tool of a welding machine (not shown) relative to the welding surface 30. The welding tool may be a laser system that applies a laser beam to the welding surface 30. An ultrasonic welding tool may also be used. Other welding methods are also possible.

[0132] The weld seam arrangement 28 includes a plurality of transport weld seams 38.1, ..., 38.3 (collectively referred to as 38). The transport weld seams 38 extend radially toward the outer periphery 19 of the electrode assembly 18 between first end points 40.1, ..., 40.3 and second end points 42.1, ..., 42.3 (collectively referred to as 40 and 42, respectively).

[0133] The first endpoint 40 is farther from the outer periphery 19 than the second endpoint 42. As shown, the first endpoints 40 have different distances from the outer periphery 19, i.e., the first endpoint 40.2 is farthest from the outer periphery 19 along the radial direction.

[0134] The first end points 40.1 and 40.3 are radially closest to the outer periphery 19, but preferably near the first end point 40.2.

[0135] As shown, the transport weld seams 38 are formed as separate, isolated lines between the first end point 40 and the second end point 42. The transport weld seams 38 are less than 2° off-parallel to each other.

[0136] The transport weld seam 38 is positioned to intersect the electrode layer 20 substantially perpendicularly, such as with a maximum deviation of 2°.

[0137] Welding can be performed by moving the welding tool linearly from second endpoint 42.1 to first endpoint 40.1, forming linear transport weld seam 38.1. Welding is then interrupted, the welding tool moves to first endpoint 40.2, and begins welding again. The welding tool moves linearly to second endpoint 42.2, forming transport weld seam 38.2. This process is repeated for transport weld seam 38.3, as shown.

[0138] This weld seam arrangement 28 may be repeated five more times around the circumference with a distance between adjacent weld seam arrangements 28. This distance is selected so that the hub portion 132 is not covered by the weld seam and so that the weld seam arrangement 28 is formed only on the structural arm 134.

[0139] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of approximately 0.099 mΩ and can achieve a maximum temperature of 76°C starting from 0°C during a transient short circuit condition.

[0140] Example B4 Referring to FIG. 10, this embodiment is identical to embodiment B1, except for the modification that the collector weld seams 39.1 and 39.2 are formed as arcs and together with the transport weld seams 38.1 and 38.3 form a closed contour, and the transport weld seam 38.2 is positioned within the contour.

[0141] Simulations by the inventors have shown that the steady-state ESR of this weld seam arrangement 28 is approximately 0.103 mΩ, and that a maximum temperature of 102°C can be achieved during a transient short circuit condition, starting from 0°C.

[0142] Example B7 11, this embodiment is identical to embodiment B4, except for the following changes: collector weld seam 39.1 is directly connected to transport weld seams 38.1 and 38.2 and is disposed radially inward from outer periphery 19, as opposed to collector weld seam 39.2; collector weld seam 39.2 is directly connected to transport weld seams 38.2 and 38.3 and is disposed radially outward toward outer periphery 19, as opposed to collector weld seam 39.1.

[0143] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of approximately 0.10 mΩ and can achieve a maximum temperature of 77°C starting from 0°C during a transient short circuit condition.

[0144] Example B6 12, the diagram illustrates a weld seam arrangement 28 obtained by welding the electrode assembly 18 to the current collector tab 24 or cell housing 12. The current collector tab 24 has a weld surface 30 bounded by a hub portion 132 and arms 134. The weld surface 30 is generally rectangular.

[0145] The weld seam arrangement 28 includes a plurality of transport weld seams 38.1, ..., 38.5 (collectively referred to as 38). The transport weld seams 38 extend radially toward the outer periphery 19 of the electrode assembly 18 between first end points 40.1, ..., 40.5, respectively, and second end points 42.1, ..., 42.5 (collectively referred to as 40 and 42, respectively).

[0146] As shown, the transport weld seam 38 is formed as a straight line connected between a first end point 40 and a second end point 42 .

[0147] The transport weld seam 38 is oriented to intersect the electrode layer 20 approximately perpendicularly, with a maximum deviation of, for example, 4°.

[0148] Welding can be performed by starting the welding tool at second end point 40.1 and moving linearly to overlapping and matching first end points 40.1 and 40.2 to form linear transport weld seam 38.1. The welding tool then moves linearly to overlapping and matching second end points 42.2 and 42.3 to form transport weld seam 38.2. This process is repeated for the remaining transport weld seams 38.3, ..., 38.5, as shown.

[0149] This weld seam arrangement 28 may be repeated five more times around the circumference, with a distance between adjacent weld seam arrangements 28. This distance is selected so that the hub portion 132 is not covered by the weld seam and so that the weld seam arrangements 28 are only formed on the overlapping arms 134.

[0150] Simulations by the inventors have shown that the steady-state ESR of this weld seam arrangement 28 is approximately 0.098 mΩ and that temperatures starting from 0°C and up to 62°C can be achieved during transient short circuit conditions.

[0151] Example B5 13, the figure illustrates a weld seam arrangement 28 obtained by welding the electrode assembly 18 to the current collector tab 24 or cell housing 12. The current collector tab 24 has a weld surface 30 bounded by a hub portion 132 and arms 134. The weld surface 30 is generally rectangular.

[0152] The weld seam arrangement 28 includes a plurality of transport weld seams 38.1, ..., 38.10 (collectively 38), each extending radially toward the outer periphery 19 of the electrode assembly 18 between a first end point 40.1, ..., 40.10 and a second end point 42.1, ..., 42.10 (collectively 40 and 42, respectively).

[0153] As shown, the transport weld seams 38.1, . . . , 38.9 are formed as arcs connected between respective first and second end points 40, 42.

[0154] The transport weld seam 38 has a major directional component that is approximately perpendicular to the electrode layer 20, for example with a maximum deviation of 2°.

[0155] The innermost and outermost transport weld seams 38.1, 38.9 are formed as 270° arcs, while transport weld seams 38.2, ..., 38.8 are formed as 180° arcs. Transport weld seam 38.10 is straight.

[0156] The weld can be performed by starting the welding tool at first end point 40.1 and moving along a 270° arc until first end point 42.1 and second end point 40.2 overlap or coincide, forming arc-shaped transport weld seam 38.1. The welding tool then moves along a 180° arc until first end point 42.2 and second end point 40.3 overlap or coincide, forming transport weld seam 38.2. This process is repeated for the remaining transport weld seams 38.3, ..., 38.9, as shown. This configuration can be mirror-image repeated as shown.

[0157] Finally, the transport weld seam 38.10 can be formed as a straight line.

[0158] This weld seam arrangement 28 may be repeated five more times around the circumference with a distance between adjacent weld seam arrangements 28. This distance is selected so that the hub portion 132 is not covered by the weld seam and the weld seam arrangements 28 are formed only on the overlapping arms 134.

[0159] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of about 0.098 mΩ and can achieve a maximum temperature of 66°C starting from 0°C during a transient short circuit condition.

[0160] Example B2 14, the figure illustrates a weld seam arrangement 28 obtained by welding the electrode assembly 18 to the current collector tab 24 or cell housing 12. The current collector tab 24 has a weld surface 30 bounded by a hub portion 132 and arms 134. The weld surface 30 is generally rectangular.

[0161] The weld seam arrangement 28 includes a plurality of either transport weld seams 38 or collector weld seams 39. The transport weld seams 38 extend at an angle of 45° to 47° relative to the circumferential direction between respective first and second end points 40, 42, while the collector weld seams 39 extend at an angle of 43° to less than 45°.

[0162] As shown, the weld seams are formed as separate, parallel straight lines between respective first and second end points 40, 42.

[0163] This weld seam arrangement 28 may be repeated five more times around the circumference, with a distance between adjacent weld seam arrangements 28. This distance is selected so that the hub portion 132 is not covered by the weld seam and so that the weld seam arrangement 28 is formed only on the arm 134.

[0164] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of approximately 0.098 mΩ and can achieve a maximum temperature of 66°C starting from 0°C during a transient short circuit condition.

[0165] Example B3 Referring to Figure 15, this figure shows a weld seam arrangement 28 obtained by welding the electrode assembly 18. The welding process will be described insofar as it differs from the previous embodiment.

[0166] The weld seam arrangement 28 includes a plurality of collector weld seams 39.1, ..., 39.11 (collectively referred to as 39). The collector weld seams 39 extend primarily along a circumferential direction parallel to the outer periphery 19 of the electrode assembly 18 between first end points 40.1, ..., 40.11 and second end points 42.1, ..., 42.11 (collectively referred to as 40 and 42, respectively).

[0167] The collector weld seams 39.1,..., 39.11 are directly connected to each other and form a continuous structure.

[0168] The first and second end points 40 and 42 of each collector weld seam are approximately the same distance from the outer periphery 19 , with the second end point 42 being slightly further away from the outer periphery 19 .

[0169] As shown, the first and second endpoints 40 and 42 are each aligned in a linear pattern.

[0170] Except for the outermost collector weld seam 39.1 and the innermost collector weld seam 39.11, the first end points 40 and second end points 42 of radially adjacent collector weld seams 39 overlap and coincide.

[0171] As shown, the collector weld seams 39 are formed as straight lines between respective first and second end points 40 and 42 .

[0172] At least one pair of collector weld seams 39 are preferably radially adjacent and form an acute angle of 45° or less, preferably 30° or less, preferably 25° or less, preferably 10° or less, preferably 8° or less. Preferably, the angles between radially adjacent collector weld seams 39 are the same.

[0173] Preferably, every other collector weld seam 39 is parallel to one another.

[0174] The collector weld seam 39 is oriented tangentially to a point on the electrode layer 20 and extends with a main direction component parallel to the circumferential direction, for example with a maximum deviation of less than 45°, preferably less than 40°, preferably less than 30°.

[0175] Welding can be performed such that the welding tool starts at first end point 40.1 and moves linearly to the matching second end points 42.2 and 42.1 to form linear collector weld seam 39.1. The welding tool then moves without interruption to the overlapping and matching first end points 40.2 and 40.3 to form collector weld seam 39.2. This process is repeated until the remaining transport weld seams 38.3, ..., 38.11 are formed, as shown.

[0176] This weld seam arrangement 28 may be repeated five more times around the circumference with a small distance between adjacent weld seam arrangements 28. This distance is selected so that the hub portion 132 is not covered by the weld seam and so that the weld seam arrangements 28 are only formed on the overlapping arms 134.

[0177] Simulations by the inventors have shown that this weld seam arrangement 28 has a steady-state ESR of approximately 0.10 mΩ and can achieve a maximum temperature of 79°C starting from 0°C during a transient short circuit condition. [Explanation of symbols]

[0178] 10 Energy Storage Cells 12 Cell housing 14 open top 16 Closed Bottom 18 Electrode Assembly 19 Outer perimeter 20 electrode layer 22 Collector's Disc 24 Collector Tabs 26 Cell Components 28 Weld Seam Arrangement 30 Welding Mask 32 Disc Center 34 Slit 36 Peripheral Rim 38 Transport Weld Seam 39 Collector weld seam 40 First endpoint 42 Second endpoint 132 Hub part 134 Arm

Claims

1. A method of welding at least one cell component (26) to an electrode assembly (18) for a supercapacitor or other energy storage cell (10), comprising: - placing each cell component (26) having an exposed welding surface (30) accessible by a welding tool for welding and an electrode assembly (18) in contact with each other; and - moving a welding tool relative to the welding surface (30) to weld each cell component (26) to the electrode assembly (18) by forming a plurality of weld seams on the welding surface (30); At least two of the formed weld seams are - a transport weld seam having a main directional component along the radial direction of the electrode assembly (18), and - a collector weld seam (39) having a major directional component along the circumferential direction of the electrode assembly (18).

2. the transport weld seam has a first end point that is a greater distance from the periphery of the electrode assembly (18) and a second end point that is a smaller distance from the periphery, the distance from the periphery to the first end point being greater than the distance from the periphery to the second end point; and / or 2. The method of claim 1, wherein the collector weld seam (39) has first and second end points that are approximately the same distance from the perimeter surface.

3. 3. The method according to claim 1, wherein the transport weld seam and / or the collector weld seam (39) is formed as a straight line or a circular arc connecting the first end point (40) and the second end point (42).

4. 4. The method of claim 1, wherein the electrode assembly (18) is a wound electrode assembly (18) including a plurality of electrode layers (20), the radial direction being substantially perpendicular to the electrode layers (20), and the circumferential direction being substantially tangential to the layers.

5. During welding, - forming a plurality of mutually separated transport weld seams (38) that are parallel to one another or that sandwich an acute angle; A method according to any one of claims 1 to 4, wherein a plurality of connected transport weld seams (38) are formed that sandwich an acute angle, said transport weld seams (38) being connected at their respective end points.

6. The individual separated transport weld seams (38) and / or the connected transport weld seams (38) include a first transport weld seam and a second transport weld seam arranged adjacent to each other along a circumferential direction; a first end point of the first transport weld seam having a greater distance from the outer periphery (19) of the electrode assembly (18) than a first end point of the second transport weld seam; Optionally, the first transport weld seam is longer than the second transport weld seam; 6. The method of claim 5, wherein optionally, the second end points (40, 42) of the first and second transport weld seams have approximately the same distance from the outer periphery (19).

7. During welding, - at least one collector weld seam (39) is formed connected to at least one weld seam, and the corresponding collector weld seam (39) and the corresponding weld seam are connected at their respective end points; and / or - Method according to claims 1 to 6, wherein at least one transport weld seam and / or at least one collector weld seam (39) connected to at least one collector weld seam (39) is formed, and corresponding collector weld seams (39) and transport weld seams (39) are connected at their respective end points.

8. The method according to any one of claims 1 to 7, wherein during welding the weld seam is formed so as to form a closed contour.

9. the cell component (26) is a current collector disk having a plurality of slits (34), preferably radial slits (34), and / or a central hole; 9. The method according to claim 1, wherein the welding surface (30) is disposed on the current collector disk, the boundary of which includes two adjacent slits (34), a central hole, and / or an outer periphery of the current collector disk.

10. the cell component (26) is a current collector tab (24) having a hub portion (132) and a plurality of arms (134), preferably radial arms (134), the arms (134) extending toward the outer periphery (19) of the electrode assembly (18); Optionally, said arm (134) includes at least one leg having a greater thickness than the remaining arm and parallel to said arm; The method according to any one of claims 1 to 9, wherein the welding surface (30) is disposed on each arm, the boundaries of which include a hub portion (132) and / or the legs.

11. 10. The method of claim 9, wherein the cell component (26) is a bottom of a cell housing (12) of the energy storage cell (10), the bottom of the cell housing (12) having a plurality of grooves, preferably radial, and / or a central hub; The method of any preceding claim, wherein the welding surface (30) is disposed within the groove and its boundaries include the sidewalls of the groove.

12. Each transport weld seam has a major directional component parallel to one of the slits (34), legs, and grooves; and / or A method according to any one of claims 9 to 11, wherein each collector weld seam (39) has a main directional component perpendicular to any of the slits (34), legs and grooves.

13. A welded seam arrangement (28) consisting solely of a welded seam obtained by welding according to the method of any one of claims 1 to 12.

14. A method of manufacturing an energy storage cell (10), preferably a supercapacitor, comprising: - providing a cell housing (12) having an open top end (14) and a closed bottom (16); - inserting the electrode assembly (18) and / or at least one cell component (26) into the cell housing (12); - welding the electrode assembly (18) to the cell housing (12) and / or to at least one cell component (26) by implementing a method according to any one of claims 1 to 12; - wetting the electrode assembly (18) with electrolyte; - closing the cell housing (12).

15. An energy storage cell (10) obtainable by the method of claim 14.

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