Current collector plate and lithium battery

Abstract

The application provides a current collecting disc and a lithium battery. The current collecting disc comprises a disc body and a protrusion. The disc body is provided with a first through hole, and the protrusion is arranged at the first through hole in the axial direction of the disc body. The profile of the protrusion matches the profile of a rivet. At least part of the protrusion is clamped between the rivet and a sealing nail when the current collecting disc is connected with the rivet and the sealing nail. The structure directly welds the winding core and the current collecting disc, and the protrusion directly contacts the rivet and the sealing nail. Compared with the prior art, the metal connecting sheet is cancelled, the structure is simpler, the overcurrent capacity is stronger, the battery internal resistance is smaller, and the high-rate fast charge and discharge performance of the full-tab lithium battery is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a current collector and a lithium battery. Background Technology

[0002] With the rapid development of the new energy industry, various new energy batteries have emerged. Lithium-ion batteries, due to their advantages such as high voltage, high specific energy, high cycle life, and long storage time, have been widely used in portable electronic devices and medium and large-sized electric equipment. Therefore, the performance requirements for lithium-ion batteries are becoming increasingly stringent. Currently, all-tab lithium batteries generally suffer from problems such as complex module structure and high internal resistance, resulting in poor high-rate charge and discharge performance. In other words, in the manufacturing process of existing lithium batteries, the positive electrode current collector is welded to the cap through connecting pieces to conduct current. This connection method results in a long current loop, which increases the internal resistance of the battery, thus weakening the overcurrent capacity of the lithium battery and hindering the improvement of the high-rate fast charge and discharge performance of the lithium battery. Summary of the Invention

[0003] This invention provides a current collector and a lithium battery to solve the problems of high internal resistance and poor high-rate charging and discharging performance of lithium batteries in the prior art.

[0004] In a first aspect, the present invention provides a collector disk, comprising: a disk body and a protrusion;

[0005] The disc body is provided with a first through hole, and the protrusion is provided at the first through hole along the axial direction of the disc body. The outline of the protrusion matches the outline of the rivet.

[0006] Wherein, when the manifold is connected to the rivet and the sealing pin, at least a portion of the protrusion is sandwiched between the rivet and the sealing pin.

[0007] According to the lithium battery provided by the present invention, the protrusion includes a first bent portion, which is formed by bending and extending from the first through hole of the disk body.

[0008] According to the lithium battery provided by the present invention, the protrusion includes a second bend, which extends from the end of the first bend away from the disk body.

[0009] According to the lithium battery provided by the present invention, the protrusion includes a third bend, which is formed by bending and extending from one end of the second bend away from the first bend.

[0010] In the lithium battery provided by the present invention, the protrusion is an annular component.

[0011] According to the lithium battery provided by the present invention, the disk body is further provided with a groove, which is formed by pressing and indenting from the end face of the disk body away from the protrusion;

[0012] In the case where the collector plate is connected to the winding core, the collector plate is welded to the positive electrode of the winding core through the groove.

[0013] According to the lithium battery provided by the present invention, when there are multiple grooves, the multiple grooves are arranged sequentially along the circumferential direction of the disk body.

[0014] According to the lithium battery provided by the present invention, the disk body is further provided with a second through hole, which is disposed between two adjacent grooves.

[0015] According to the lithium battery provided by the present invention, the disk and the protrusion are integrally formed.

[0016] In a second aspect, the present invention also provides a lithium battery, comprising: a core, a rivet, a sealing pin, and a current collector as described in any of the preceding claims;

[0017] The two sides of the protrusion of the collector plate are respectively attached to the inner wall of the rivet and the outer surface of the sealing nail; the side of the collector plate away from the protrusion is welded to the positive electrode of the core.

[0018] The present invention provides a current collector and a lithium battery. The current collector consists of a disk body and protrusions. The protrusions enable the current collector to contact the sealing pins and rivets, thereby enabling the current to flow through the lithium battery core. The lithium battery provided by the present invention eliminates the metal connecting piece. After the core is directly welded to the current collector, it is directly connected to the rivets and sealing pins through the protrusions. Compared with the prior art, the manufacturing process of this current collector is simpler, and it has strong current carrying capacity and low battery internal resistance, which can improve the high-rate fast charge and discharge performance of all-tab lithium batteries. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is one of the schematic diagrams of the collector disk structure provided in the embodiments of the present invention;

[0021] Figure 2 This is one of the schematic diagrams of the installation structure of the collector disk provided in the embodiment of the present invention;

[0022] Figure 3This is the second schematic diagram of the collector disk structure provided in the embodiment of the present invention;

[0023] Figure 4 This is a second schematic diagram of the installation structure of the collector disk provided in an embodiment of the present invention;

[0024] Figure 5 This is the third schematic diagram of the collector disk structure provided in the embodiment of the present invention;

[0025] Figure 6 This is the third schematic diagram of the installation structure of the collector disk provided in the embodiment of the present invention;

[0026] Figure 7 This is the fourth schematic diagram of the collector disk structure provided in the embodiment of the present invention;

[0027] Figure 8 This is the fourth schematic diagram of the installation structure of the collector disk provided in the embodiment of the present invention;

[0028] Figure 9 This is the fifth schematic diagram of the collector disk structure provided in the embodiment of the present invention;

[0029] Figure 10 This is the fifth schematic diagram of the installation structure of the collector plate provided in the embodiment of the present invention;

[0030] Figure 11 This is the sixth schematic diagram of the collector disk structure provided in the embodiment of the present invention;

[0031] Figure 12 This is the sixth schematic diagram of the installation structure of the collector plate provided in the embodiment of the present invention;

[0032] Figure 13 This is one of the top view structural schematic diagrams of the collector disk provided in the embodiments of the present invention;

[0033] Figure 14 yes Figure 13 A schematic diagram of the AA cross-sectional structure;

[0034] Figure 15 This is a second top view of the collector structure provided in an embodiment of the present invention;

[0035] Figure 16 yes Figure 15 A schematic diagram of the AA cross-sectional structure;

[0036] Figure label:

[0037] 1: Disc body; 11: First through hole; 12: Groove; 13: Second through hole; 2: Protrusion; 21: First bend; 22: Second bend; 23: Third bend; 3: Rivet; 4: Sealing nail. Detailed Implementation

[0038] In the description of this invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "provided with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] The following is combined Figures 1 to 12 The present invention describes the lithium battery and its preparation method.

[0042] In a first aspect, the current collector provided in the embodiments of the present invention includes: a disk body 1 and a protrusion 2.

[0043] The disc body 1 is provided with a first through hole 11, and the protrusion 2 is provided at the first through hole 11 along the axial direction of the disc body 1. The outline of the protrusion 2 matches the outline of the rivet 3.

[0044] In the case where the manifold is connected to the rivet 3 and the sealing nail 4, at least part of the protrusion 2 is sandwiched between the rivet 3 and the sealing nail 4.

[0045] Specifically, such as Figure 1 As shown, the collector plate has two end faces. In actual operation, its back side is in contact with the positive electrode exposed foil of the core. A first through hole 11 is provided at the center position. A protrusion 2 is provided on its front side. The protrusion 2 extends along the axial direction of the collector plate body 1 and is connected to the first through hole 11.

[0046] The function of protrusion 2 is to directly guide the current to rivet 3 and sealing nail 4. Compared with the existing technology, the connecting piece structure in the existing technology is eliminated, making the current collector structure simpler, reducing the battery internal resistance, and increasing the overcurrent intensity.

[0047] To maximize the contact area between rivet 3 and protrusion 2, a larger contact area results in stronger current carrying capacity, such as... Figure 2As shown, the middle of the rivet 3 is also provided with a through hole, and the size of the through hole is adapted to the outer contour size of the protrusion 2, so as to achieve fitting between the two.

[0048] The protrusion 2 may be formed by extending the disc body 1 from the first through hole 11, or may be manufactured separately and then welded to the first through hole 11 of the disc body 1.

[0049] In order to ensure the current conduction effect, the protrusion 2 and the disc body 1 are preferably made of the same metal material, for example, aluminum alloy.

[0050] The shape and size of the disc body 1 are not particularly limited, and it can be manufactured according to the cross-sectional shape and size of the winding core. When the winding core is cylindrical, the shape of the disc body 1 is correspondingly disc-shaped.

[0051] The shape and size of the protrusion 2 are also not particularly limited herein, and only need to match the shape and size of the rivet 3 and the sealing nail 4. After the protrusion 2 is fitted with the rivet 3, the formed annular cavity communicates with the first through hole 11. On one hand, it provides an injection port for battery electrolyte injection, and on the other hand, it facilitates the embedding of the sealing nail 4 to realize the sealing operation of the lithium battery.

[0052] The current collector disc and the lithium battery provided by the embodiments of the present invention, wherein the current collector disc is composed of the disc body 1 and the protrusion 2, and the contact between the current collector disc and the sealing nail 4 and the rivet 3 is realized through the protrusion 2, thereby conducting the current of the lithium battery winding core. Compared with the prior art, the lithium battery provided by the present invention eliminates the metal connecting sheet. After the winding core is directly welded to the current collector disc, the protrusion 2 is in direct contact with and welded to the rivet 3 and the sealing nail 4. The preparation process of the current collector disc is simpler, and it has strong overcurrent capability and small battery internal resistance, which can improve the high-rate rapid charge and discharge performance of full-tab lithium batteries.

[0053] In an alternative embodiment, the protrusion 2 includes a first bending portion 21, and the first bending portion 21 is formed by bending and extending from the first through hole 11 of the disc body 1.

[0054] Specifically, the first bending portion 21 formed by bending and extending upward from the first through hole 11 of the disc body 1 is the protrusion 2. In the embodiment of the present invention, the first bending portion 21 may be as Figure 1 the linear structure perpendicular to the disc body 1 shown, or may be as Figure 3 the structure with an inverted "eight"-shaped cross-section shown, or may also be a structure with an "eight"-shaped cross-section shown.

[0055] As Figure 3 shown, when the first bending portion 21 is an "eight"-shaped structure, the included angle formed between the first bending portion 21 and the disc body 1 is greater than 90 degrees, but the angle should not be too large, so as not to affect the injection of electrolyte.

[0056] Figure 2 is Figure 1 The diagram shows the assembly structure of the current collector, rivet 3, and sealing nail 4. The outer side of the first bend 21 is in contact with the inner surface of the rivet 3, and the inner side of the first bend 21 is in contact with the sealing nail 4. After the three are installed, the V-shaped groove at the connection between the rivet 3 and the sealing nail 4 is laser welded to achieve the connection of the three and thus realize the current conduction.

[0057] Similarly, Figure 4 for Figure 3 The diagram shows the assembly structure of the current collector, rivet 3, and sealing nail 4. When the sealing nail 4 is a conical structure, the size of the upper end of the first bending part 21 matches the sealing nail 4 and rivet 3 to achieve contact between the three. After the three are installed, the V-shaped groove at the connection between the rivet 3 and the sealing nail 4 is laser welded to achieve the connection between the three, thereby enabling current conduction.

[0058] In an optional embodiment, the protrusion 2 includes a second bend 22, which is formed by bending and extending from the end of the first bend 21 away from the disk body 1.

[0059] Specifically, depending on actual needs, the end of the first bent portion 21 can be bent and extended to form a second bent portion 22 to adapt to the shape and size of the rivet 3 and the sealing nail 4.

[0060] In this embodiment of the invention, the second bending portion 22 can be as follows: Figure 5 The horizontal structure shown has a surface of the second bend 22 parallel to the disk surface of the disk body 1; it can also be as follows: Figure 7 The cross-section shown is an inverted "V" shape; other bent and extended shapes are also possible. It should be able to achieve contact with the inner surface of the rivet 3 and the outer surface of the sealing nail 4, satisfying the requirements for current conduction.

[0061] Figure 6 for Figure 5 The diagram shows the assembly structure of the current collector, rivet 3, and sealing nail 4. The outer side of the first bend 21 and the lower side of the second bend 22 are all in contact with the inner surface of the rivet 3. The upper side of the second bend 22 and part of the inner side of the first bend 21 are in contact with the sealing nail 4. After the three are installed, the V-shaped groove at the connection between the rivet 3 and the sealing nail 4 is laser welded to achieve the connection of the three and thus realize the current conduction.

[0062] Similarly, Figure 8 for Figure 7The diagram shows the assembly structure of the current collector, rivet 3, and sealing nail 4. When the sealing nail 4 is a conical structure, the dimensions of the first bending part 21 and the second bending part 22 match those of the sealing nail 4 and the rivet 3 to achieve contact between the three. After the three are installed, the V-shaped grooves at the connection points are laser welded to achieve the connection between the three, thereby enabling current conduction.

[0063] In an optional embodiment, the protrusion 2 includes a third bend 23, which is formed by bending and extending from the end of the second bend 22 away from the first bend 21.

[0064] Specifically, depending on actual needs, the end of the second bend 22 can be bent and extended to form a third bend 23 to adapt to the shape and size of the rivet 3 and the sealing nail 4.

[0065] In the embodiments of the present invention, in the above Figure 5 Based on the structure shown, the third bend 23 can be as follows: Figure 9 The vertical structure shown is perpendicularly connected to the second bend 22, that is, parallel to the first bend 21; it can also be as follows: Figure 11 The vertical structure shown is perpendicularly connected to the second bend 22, but not parallel to the first connecting part.

[0066] The specific setting method can be selected based on the shape and size of the rivet 3 and sealing nail 4 in the actual situation, as long as the current conduction requirements are met.

[0067] Based on the connection of the current collector, rivet 3 and sealing nail 4, the protrusion 2 with the largest contact surface can be selected for connection to further enhance the current conduction capability.

[0068] Figure 10 for Figure 9 The diagram shows the assembly structure of the current collector, rivet 3, and sealing nail 4. The outer side of the first bend 21, the lower surface of the second bend 22, and the outer side of the third bend 23 are in contact with the inner surface of the rivet 3. The inner side of the first bend 21 is in contact with the sealing nail 4, and the upper surface of the second bend 22 and the inner surface of the third bend 23 are in contact with the sealing nail 4. After the three components are installed, the V-shaped grooves at the connection points are laser welded to achieve the connection of the three components and thus enable current conduction.

[0069] Similarly, Figure 12 for Figure 11 The diagram shows the assembly structure of the manifold, rivet 3, and sealing nail 4, and the connection method is as described above. Figure 10 As shown, it will not be elaborated further here.

[0070] In an optional embodiment, protrusion 2 is an annular element.

[0071] Specifically, to facilitate electrolyte filling of the battery during actual operation, such as Figure 13 As shown, the protrusion 2 can be made into a ring and connected to the first through hole 11 on the disk body 1.

[0072] The ring-shaped component can be circular, square, or other shapes, as long as its shape matches that of the rivet 3 and the sealing nail 4.

[0073] In an optional embodiment, the disc body 1 is further provided with a groove 12, which is formed by pressing and indenting from the end face of the disc body 1 away from the protrusion 2.

[0074] In the case where the collector plate is connected to the core, the collector plate is welded to the positive electrode of the core through the groove 12.

[0075] Specifically, the end face opposite to protrusion 2 of the current collector is the back side. Since the back side needs to contact the positive electrode exposed foil of the winding core, and to facilitate pressing the current collector into the positive electrode exposed foil, as follows... Figure 13 As shown, a groove 12 is provided on the collector plate, and the groove 12 can be a fan-shaped structure. For example... Figure 14 As shown, the groove 12 is formed by pressing the surface of the collector plate against the back side.

[0076] In operation, the groove 12 is pressed into the positive electrode exposed foil, and laser welding is performed at the groove 12 to the positive electrode exposed foil to ensure the strong connection and thus ensure the conduction of current.

[0077] In an optional embodiment, when there are multiple grooves 12, the multiple grooves 12 are arranged sequentially along the circumferential direction of the disk body 1.

[0078] Specifically, to further improve the current collection effect, multiple grooves 12 can be provided on the disk body 1 of the current collector, such as... Figure 13 As shown, four grooves 12 are provided. To ensure the uniformity of the current, the four grooves 12 are arranged around the protrusion 2. Of course, other numbers of grooves 12 are also possible; this is just an example.

[0079] Besides the fan shape, the groove 12 can also be square, round or other shapes. The specific shape is set according to the actual situation and is not specifically limited here. As long as it can facilitate pressing in the positive electrode exposed foil while ensuring current conduction, it is fine.

[0080] In an optional embodiment, the disc body 1 is further provided with a second through hole 13, which is located between two adjacent grooves 12.

[0081] Specifically, such as Figure 13As shown, a second through hole 13 is provided between every two adjacent grooves 12. In this embodiment of the invention, the second through hole 13 is a leakage hole, which facilitates the electrolyte to flow out from the leakage hole.

[0082] The second through hole 13 can be as follows: Figure 13 As shown, each group of leakage holes includes three small through holes. The three small through holes are arranged radially along the disk body 1, and the inner diameter of the three small through holes increases sequentially from the inside to the outside. The leakage hole can also be set as an elongated through hole, which can be of regular size or irregular size. Therefore, the number and size of the second through hole 13 are not specifically limited, as long as the electrolyte can flow out from here.

[0083] In an optional embodiment, the disc body 1 and the protrusion 2 are integrally formed.

[0084] Specifically, in order to simplify the operation process and ensure the current conduction effect, the disk body 1 and the protrusion 2 of the current collector are manufactured in one piece, that is, the disk body 1 is extended upward by the first through hole 11 of the disk body 1 to form the protrusion 2.

[0085] The following provides two specific embodiments to illustrate the current collector disk provided by the present invention:

[0086] Example 1:

[0087] like Figure 15 and Figure 16 As shown, the thickness of the manifold is 0.3 mm and the diameter is 40 mm; four fan-shaped grooves 12 are evenly distributed on the disc body 1, and three leakage holes are provided between every two grooves 12.

[0088] The protrusion 2 is composed of a first bend 21 and a second bend 22. The outer diameter of the second bend 22 of the protrusion 2 is 3.8 mm and the height is 1.9 mm. The taper of the first bend 21 is 1:10 and the height is 2.7 mm.

[0089] Correspondingly, the inner hole of the rivet 3 that is installed and connected to it has an upper diameter of 5mm and a height of 2mm; a middle diameter of 4mm and a height of 0.5mm; and a lower taper of 1:10 and a height of 2.3mm.

[0090] The upper section of the sealing nail 4 has a diameter of 4.41 mm and a height of 1.7 mm; the lower section has a diameter of 3.61 mm and a height of 1.5 mm.

[0091] The aforementioned manifold, rivet 3, and sealing nail 4 are made of pure aluminum.

[0092] During actual installation, first, assemble the cap with the collector plate, so that the protrusion 2 on the collector plate passes through the hole on the rivet 3;

[0093] Secondly, the protrusion 2 of the collector plate is shaped and enlarged using equipment. The enlarged inner hole of the protrusion 2 makes the diameter of the second bend 22 4.4mm and the diameter of the first bend 21 3.4mm.

[0094] Then, install the sealing nail 4 so that the sealing nail 4 and the rivet 3 are on the same plane;

[0095] Finally, the groove 12 at the junction of the protrusion 2, rivet 3 and sealing nail 4 is laser welded.

[0096] Example 2:

[0097] like Figure 13 and Figure 14 As shown, the thickness of the manifold is 0.3 mm and the diameter is 40 mm; four fan-shaped grooves 12 are evenly distributed on the disc body 1, and three leakage holes are provided between every two grooves 12.

[0098] The outer diameter of the upper opening of the first bend 21 of the protrusion 2 is 3.8 mm, the taper is 1:10, and the height is 2.7 mm;

[0099] Correspondingly, the upper section of the inner hole of the rivet 3 that is installed and connected to it has a diameter of 5mm and a height of 2mm; the middle section has a diameter of 4mm and a height of 0.5mm; and the lower section has a taper of 1:10 and a height of 2.3mm.

[0100] The upper section of the sealing nail 4 has a diameter of 5.01 mm and a height of 1.7 mm; the lower section has a diameter of 3.61 mm and a height of 1.5 mm.

[0101] The aforementioned manifold, rivet 3, and sealing nail 4 are made of pure aluminum.

[0102] During actual installation, first, assemble the cap with the collector plate, so that the protrusion 2 on the collector plate passes through the hole on the rivet 3;

[0103] Secondly, the protrusion 2 of the collector plate is shaped and enlarged using equipment. The inner hole of the enlarged protrusion 2 has a diameter of 3.4mm at the middle of its first bent part 21.

[0104] Then, install the sealing nail 4 so that the sealing nail 4 and the rivet 3 are on the same plane;

[0105] Finally, the groove 12 at the junction of the protrusion 2, rivet 3 and sealing nail 4 is laser welded.

[0106] Secondly, embodiments of the present invention provide a lithium battery, comprising: a core, a rivet 3, a sealing nail 4, and a current collector as described in any of the above.

[0107] The two sides of the protrusion 2 of the collector plate are respectively attached to the inner wall of the rivet 3 and the outer surface of the sealing nail 4; the side of the collector plate body 1 away from the protrusion 2 is welded to the positive electrode of the core.

[0108] Specifically, the current collector has been described above and will not be repeated here. Any current collector included here is applicable to the lithium battery provided in the embodiments of the present invention.

[0109] The lithium battery provided in this embodiment of the invention has a current collector plate body 1 welded to the positive electrode of the winding core, and rivets 3 and sealing nails 4 respectively attached to both sides of the protrusion 2 of the current collector plate, realizing direct contact and increasing the contact area between the current collector plate and the rivets 3 and sealing nails 4, thereby enhancing the current carrying capacity.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A collector disk, characterized in that, include: Disc body and protrusions; The disc body is provided with a first through hole, and the protrusion is provided at the first through hole along the axial direction of the disc body. The outline of the protrusion matches the outline of the rivet. Wherein, when the current collector is connected to the rivet and the sealing pin, at least part of the protrusion is sandwiched between the rivet and the sealing pin; the current collector contacts the sealing pin and the rivet through the protrusion, so that the current of the lithium battery core is turned on; the annular cavity formed by the protrusion facilitates the insertion of the sealing pin to achieve the sealing operation of the lithium battery. The protrusion includes a first bend that extends from the first through hole in the disk body; the protrusion also includes a second bend that extends from the end of the first bend away from the disk body; and the protrusion also includes a third bend that extends from the end of the second bend away from the first bend. The two protruding sides of the manifold are respectively attached to the inner wall of the rivet and the outer surface of the sealing nail.

2. The collector disk according to claim 1, characterized in that, The protrusion is a ring-shaped part.

3. The collector disk according to claim 1, characterized in that, The disc body is also provided with a groove, which is formed by pressing and indenting from the end face of the disc body away from the protrusion. In the case where the collector plate is connected to the winding core, the collector plate is welded to the positive electrode of the winding core through the groove.

4. The collector disk according to claim 3, characterized in that, When there are multiple grooves, the multiple grooves are arranged sequentially along the circumferential direction of the disk body.

5. The collector disk according to claim 4, characterized in that, The disc body is also provided with a second through hole, which is located between two adjacent grooves.

6. The collector disk according to claim 1, characterized in that, The disc body and the protrusion are integrally formed.

7. A lithium battery, characterized in that, include: Core, rivet, sealing pin, and manifold as described in any one of claims 1 to 6; The side of the collector plate facing away from the protrusion is welded to the positive electrode of the winding core.

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