Cylindrical battery, manufacturing method thereof and electric equipment

Abstract

The invention discloses a cylindrical battery and a manufacturing method thereof and electric equipment, the cylindrical battery comprises a battery cell, the battery cell is a full-tab roll core and comprises a coating part and an empty foil part, the empty foil part is close to the outer edge of one end of the full-tab roll core in a first direction, the empty foil part comprises a plurality of empty foil materials which are adjacently arranged in a second direction, and the empty foil materials are arranged in the first direction; one part of the empty foil has a first height, and the other part of the empty foil has a second height; the current collector comprises a body and a lug boss; wherein the empty foil with the first height is connected with the body, and the empty foil with the second height is connected with the protruding part through laser heat conduction welding. According to the cylindrical battery disclosed by the invention, the hollow foil part with the height difference and the current collector with the height difference are arranged, so that the connection area and the connection tightness between the end surface of the hollow foil part and the end surface of the current collector can be increased, the welding area of laser heat conduction welding is larger, the welding is tighter, and the process effect of the laser heat conduction welding is further improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a cylindrical battery, a method for manufacturing the same, and an electrical device thereof. Background Technology

[0002] Cylindrical batteries, with their advantages of high structural strength, good manufacturing consistency, directional pressure relief, and no thermal propagation, have become a hot research area in the current power battery field. The resulting demands place higher requirements on the power performance of cylindrical battery cells.

[0003] However, traditional cylindrical cells achieve electrical connection by connecting the core and the casing / cap with tabs, and the thickness and width of the tabs themselves limit the current carrying capacity of the cell structure.

[0004] To address this, the industry has proposed the following solutions to improve the overcurrent capability of cylindrical battery cells:

[0005] (1) Multi-tab solution: This solution aims to improve the overcurrent capacity of the battery cell by increasing the number of tabs. However, since the manufacturing difficulty increases significantly with the increase in the number of tabs, this solution cannot meet the requirements of high-rate charging and discharging.

[0006] (2) Clasp-type solution: Empty foil for positive and negative electrodes is left at both ends of the core. The empty foil area is processed and compressed into a solid shape using physical methods. Then, current collectors are welded onto the compressed empty foil area to lead out electrical connections. The problem with this solution is that metal particles may be generated during the processing and compression of the empty foil area, which can easily cause internal short circuits in the battery and create safety risks.

[0007] (3) Stacked tab (full tab) scheme: The empty foil material at the end face of the core is cut into strips perpendicular to the winding direction. During winding, the folded and cut empty foil areas are stacked and compacted, and then the current collector is welded on to lead out the electrical connection. The problems with this scheme are: the die-cutting tab process is difficult, and the efficiency and yield are hard to guarantee; the flatness of the compacted empty foil area is poor, which limits the subsequent current collector welding process.

[0008] In addition, the above-mentioned methods usually use laser penetration welding to connect the tabs and the current collector. The welding area has a high temperature, which causes greater damage to the core and results in a low yield of the final product. Summary of the Invention

[0009] One objective of this invention is to provide a cylindrical battery that can at least solve the technical problems of existing technologies that use laser penetration welding to connect the tabs and current collectors, resulting in high welding temperatures, significant damage to the core, and low yield of the final product.

[0010] Another object of the present invention is to provide a method for manufacturing a cylindrical battery, for manufacturing the above-mentioned cylindrical battery.

[0011] Another object of the present invention is to provide an electrical device comprising the above-described cylindrical battery.

[0012] To achieve the above objectives, the present invention provides the following technical solutions.

[0013] A cylindrical battery according to a first aspect of the present invention includes: a battery cell, the battery cell being a full-tab winding core with a central axis extending along a first direction, the full-tab winding core including a coated portion coated with active material and an empty foil portion without active material coated, the empty foil portion being near the outer edge of one end of the full-tab winding core in the first direction, the empty foil portion including a plurality of empty foil materials disposed adjacently in a second direction, the second direction being not parallel to the first direction, in the first direction, a portion of the empty foil materials having a first height, another portion of the empty foil materials having a second height, the first height being greater than the second height; a current collector, the current collector including a body and a protrusion, the protrusion protruding from one side surface of the body; wherein the empty foil material having the first height is connected to the body, and the empty foil material having the second height is connected to the protrusion by laser thermal conductive welding.

[0014] Optionally, the protrusion includes: a first connecting portion and a second connecting portion, wherein the first connecting portion is an annular member, one end of the first connecting portion is connected to the body along the first direction, the second connecting portion closes the other end of the first connecting portion, and the second connecting portion and the first connecting portion cooperate to form a groove.

[0015] Optionally, in the first direction, both sides of the second connecting portion are planar, and the thickness of the second connecting portion is 0.1mm-0.4mm.

[0016] Optionally, the current collector is the outer casing of the cylindrical battery or a current collector plate.

[0017] Optionally, the number of protrusions on a single body is multiple, and the multiple protrusions are spaced apart around the first direction; and / or, the outer contour of the protrusion is trapezoidal or rectangular, and when the outer contour is trapezoidal, the short side of the trapezoid is close to the central axis of the full-pole lug core, and when the outer contour is rectangular, the two ends of the rectangle are straight sides or semi-circular sides.

[0018] Optionally, the current collector is a single piece.

[0019] Optionally, the empty foil having the second height includes: a first segment extending along the first direction; and a second segment extending along the second direction, with one end in the second direction connected to the first segment, the end face of the second segment in the first direction being connected to the surface of the protrusion by laser thermal welding.

[0020] Optionally, in the first direction, the protrusion has a height d, and in the second direction, there is a gap D between two adjacent layers of the hollow foil, where d > D.

[0021] According to a second aspect of the present invention, a method for manufacturing a cylindrical battery, wherein the cylindrical battery is any of the cylindrical batteries described above, the method includes the following steps: applying a force toward the empty foil portion to a current collector along a first direction, such that the empty foil material corresponding to the protrusion has a second height after bending; attaching the protrusion to the end face of the empty foil portion; and connecting the empty foil material having the second height to the protrusion by laser thermal conductive welding.

[0022] According to a third aspect of the present invention, an electrical device includes any of the cylindrical batteries described above, or a cylindrical battery prepared by any of the methods described above for manufacturing a cylindrical battery.

[0023] The cylindrical battery according to an embodiment of the present invention mainly consists of a battery cell and a current collector. On the one hand, by adopting a full-tab winding core, the connection area between the tabs and the current collector can be expanded, thereby improving the current carrying capacity of the battery cell. On the other hand, by providing an empty foil portion with a height difference and a current collector with a height difference, the connection area and connection tightness between the end face of the empty foil portion and the end face of the current collector can be increased. That is, the connection area and connection tightness between the end face welding area of ​​the empty foil portion and the end face of the current collector can be increased, thereby improving the process effect of laser thermal conductive welding.

[0024] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0026] Figure 1 This is a schematic diagram of the winding of a cylindrical battery cell according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the installation of the current collector and the empty foil section according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the current collector extrusion section of the hollow foil material according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram showing the connection of the current collector and the empty foil portion by laser thermal conductive welding according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of a process for connecting the current collector and the empty foil portion by laser thermal conductive welding according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the existing laser penetration welding process;

[0032] Figure 7 This is a schematic diagram of the structure of a cylindrical battery at one angle according to an embodiment of the present invention;

[0033] Figure 8 This is a structural schematic diagram of a cylindrical battery from another angle according to an embodiment of the present invention;

[0034] Figure 9 This is a partial exploded view of a cylindrical battery according to an embodiment of the present invention;

[0035] Figure 10 This is a vertical cross-sectional view of a cylindrical battery according to an embodiment of the present invention.

[0036] Attached icon number

[0037] Battery cell 1; Coating section 11; Empty foil section 12; Empty foil material 121; First section body 1211; Second section body 1212; First diaphragm 13; Second diaphragm 14;

[0038] Current collector 2; Body 21; First surface 211; Second surface 212; Protrusion 22; First connecting part 221; Second connecting part 222; Groove 223;

[0039] Top cover 3;

[0040] 4. Outer shell;

[0041] Molten pool a'; Effective welding zone b';

[0042] Molten pool (a); Effective welding zone (b); Heat-affected zone (c);

[0043] First altitude H1; Second altitude H2. Detailed Implementation

[0044] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0045] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0046] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0047] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0048] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0049] The cylindrical battery according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0050] like Figures 1 to 5 ,as well as Figures 7 to 10 As shown, a cylindrical battery according to an embodiment of the present invention includes: a battery cell 1 and a current collector 2.

[0051] Specifically, the battery cell 1 is a full-pole coil core extending along a first direction. The full-pole coil core includes a coated portion 11 with active material and an uncoated foil portion 12. The foil portion 12 is located near the outer edge of one end of the full-pole coil core in the first direction. The foil portion 12 includes multiple adjacent foil pieces 121 arranged in a second direction, which is not parallel to the first direction. In the first direction, a portion of the foil pieces 121 has a first height H1, and another portion has a second height H2, where the first height H1 is greater than the second height H2. The current collector 2 includes a body 21 and a protrusion 22, which protrudes from one side surface of the body 21. The foil pieces 121 with the first height H1 are connected to the body 21, and the foil pieces 121 with the second height H2 are connected to the protrusion 22 via laser thermal welding.

[0052] In other words, the cylindrical battery according to an embodiment of the present invention mainly consists of a cell 1 and a current collector 2, wherein the cell 1 is a full-tab wound core, and the full-tab wound core can be prepared by winding, for example by winding along... Figure 1The arrows indicate the winding direction in which the multi-layered electrode sheet is formed. This electrode sheet can be either a positive or negative electrode sheet. A separator is placed between the positive and negative electrode sheets to effectively prevent short circuits between the positive and negative electrodes. When manufacturing a full-tab core, the positive electrode sheet, separator, and negative electrode sheet can be stacked and then wound to form a full-tab core.

[0053] It is understood that, along the axial direction of the full-tab core, i.e., the first direction, the full-tab core includes adjacently arranged coating portions 11 and empty foil portions 12. The empty foil portion 12 of the positive electrode can serve as the positive electrode tab, and the empty foil portion 12 of the negative electrode can serve as the negative electrode tab. Moreover, each electrode layer includes adjacently arranged coating portions 11 and empty foil portions 12. The surface of the coating portion 11 is coated with an active material, while the surface of the empty foil portion 12 is not coated with an active material. For example, the flattened positive and negative electrode sheets may have empty foil portions 12 without positive and negative active materials respectively provided at both ends in the first direction. Furthermore, during coating, both the positive and negative electrode sheets can be continuously coated, i.e., no gaps are provided along the winding direction.

[0054] Furthermore, by winding in the second direction, multiple layers of empty foil 121 are formed, meaning that the empty foil portion 12 includes a plurality of empty foils 121 arranged sequentially along the second direction. The axial direction of the full-pole lug core can be the first direction, and the winding direction can be the second direction. The first direction and the second direction are not parallel, meaning that there is an angle between them, for example, the first direction and the second direction are perpendicular to each other.

[0055] Furthermore, in the first direction, the empty foil portion 12 is close to the outer edge of at least one end of the full-pole ear core. The interaction between the coating portion 11 and the empty foil portion 12 will be illustrated below with specific examples.

[0056] For example, the height direction of the electrode is vertical. Along the vertical direction, the outer surface of the middle part of the electrode is coated with active material, while the outer surfaces of the upper and lower parts of the electrode are not coated with active material.

[0057] For example, the lower and middle surfaces of the electrode are coated with active material, while the upper surface of the electrode is not coated with active material.

[0058] For example, the upper and middle surfaces of the electrode are coated with active material, while the lower surface of the electrode is not coated with active material.

[0059] In other words, the wound all-electrode core includes a coated portion 11 and an empty foil portion 12, wherein the coated portion 11 has an active material and the empty foil portion 12 does not have an active material. In this embodiment, the empty foil portion 12 is provided at least one end of the battery cell 1 in the first direction, that is, an open space is left, which greatly improves the electrolyte wetting efficiency and the exhaust speed of the gas generated inside the battery cell 1, and greatly improves the production efficiency and product safety.

[0060] Furthermore, the empty foil portion 12 is connected to the current collector 2. It should be noted that when the lower middle or upper middle part of the above-mentioned all-pole ear core is coated with active material, the end of the all-pole ear core coated with active material can be connected to an existing current collector plate, etc., which will not be elaborated here.

[0061] Furthermore, the current collector 2 mainly consists of a body 21 and a protrusion 22. For ease of explanation, one side of the body 21 in its thickness direction can be defined as the first surface 211, and the other side as the second surface 212. The first surface 211 is close to the battery cell 1, and the second surface 212 is away from the battery cell 1. In this case, the protrusion 22 protrudes from the first surface 211, and the protrusion 22 can also be defined as a boss.

[0062] The protrusion 22 of the current collector 2 is connected to the end face of the empty foil portion 12 by laser thermal conductive welding. For example, the first direction is the vertical direction, the height direction of the full-electrode core extends in the vertical direction, the upper part of the full-electrode core has an empty foil portion 12, the lower part also has an empty foil portion 12, and the middle part has a coating portion 11. The current collector 2 may include a body 21 extending in the horizontal direction and a protrusion 22 protruding from the surface of the body 21. For the empty foil portion 12 in the upper part of the full-electrode core, the body 21 is located above the empty foil portion 12, and the protrusion 22 extends downward and is connected to the upper end face of the empty foil portion 12 by laser thermal conductive welding. For the empty foil portion 12 in the lower part of the electrode sheet, the body 21 is located below the empty foil portion 12, and the protrusion 22 extends upward and is connected to the lower end face of the empty foil portion 12 by laser thermal conductive welding.

[0063] It should be noted that, as Figure 6 As shown, in existing laser penetration welding, when laser welding current collector 2 and cell 1, the laser needs to be focused near the end face of the protrusion 22 of current collector 2 to melt part of current collector 2 to connect the empty foil part 12 of cell 1 and the end face of the protrusion 22 of current collector 2. Figure 6 The image shows the molten pool a' and the effective welding zone b'. (See image for details.) Figure 5 As shown, in this embodiment, the welding method adopts heat-conducting welding, that is, the molten pool caused by welding does not directly penetrate the welding area, but the foil is heated and melted through the heat-affected zone of the molten pool to achieve the connection between the protrusion 22 and the empty foil 121. Figure 5 The diagram shows the molten pool (a), the effective welding zone (b), and the heat-affected zone (c).

[0064] As can be seen, in this embodiment, the laser welding method using thermally conductive welding has a lower laser spot power density than laser penetration welding, making it less likely for the molten pool to penetrate the current collector 2 and reducing the possibility of burning the battery cell 1. In this embodiment, by using thermally conductive welding, the local temperature of the welding area is lower than that of penetration welding, thus causing less damage to the core.

[0065] Therefore, the cylindrical battery according to the present invention mainly consists of a cell 1 and a current collector 2. On the one hand, by adopting a full-tab winding core, the connection area between the tabs and the current collector 2 can be expanded, thereby improving the current carrying capacity of the cell 1. On the other hand, by providing an empty foil portion 12 with a height difference and a current collector 2 with a height difference, the connection area and connection tightness between the end face of the empty foil portion 12 and the end face of the current collector 2 can be increased. That is, the connection area and connection tightness between the welding area of ​​the end face of the empty foil portion 12 and the end face of the current collector 2 can be increased, thereby improving the process effect of laser heat-conducting welding.

[0066] Optionally, the width of the coating area of ​​the negative electrode should be greater than the width of the coating area of ​​the positive electrode. Here, width refers to the end dimension of the electrode in the winding direction, i.e., along the winding direction or the length direction of the electrode, the two ends of the negative electrode extend beyond the two ends of the positive electrode. For example, before winding, both the positive and negative electrodes extend in the left-right direction, with the left end of the positive electrode shorter than the left end of the negative electrode, and the right end of the positive electrode shorter than the right end of the negative electrode. During winding, the electrodes are wound from left to right. In this embodiment, by limiting the dimensional relationship between the negative and positive electrodes, safety performance is improved, and short circuits are effectively prevented.

[0067] Optionally, the separator has two layers. For ease of explanation, the two separator layers can be distinguished as a first separator 13 and a second separator 14. The first separator 13 is located between the positive electrode and the negative electrode, and the negative electrode is located between the first separator 13 and the second separator 14. Along the winding direction or the length direction of the electrode, the two ends of the first separator 13 extend beyond the two ends of the positive electrode, and the two ends of the second separator 14 extend beyond the two ends of the negative electrode. For example, before winding, the right end of the first separator 13 extends beyond the right end of the positive electrode, the right end of the negative electrode extends beyond the right end of the first separator 13, and the second separator 14 extends beyond the right end of the negative electrode. During winding, the winding proceeds from left to right. In this embodiment, by defining the dimensional relationship between the positive electrode, the negative electrode, and the separator, it is beneficial to improve safety performance and effectively prevent short circuits.

[0068] Optionally, after the full-tab core is wound, the gap between each pair of adjacent empty foils 121 is uniform in the second direction, which is beneficial to improving battery performance.

[0069] Optionally, the current collector 2 can be made of metals such as nickel, aluminum, nickel-plated aluminum, copper, nickel-plated copper, steel, nickel-plated steel, or stainless steel. By using the above materials, the battery performance can be effectively improved.

[0070] According to one embodiment of the present invention, the protrusion 22 includes a first connecting portion 221 and a second connecting portion 222. The first connecting portion 221 is an annular component. Along a first direction, one end of the first connecting portion 221 is connected to the body 21, and the second connecting portion 222 closes the other end of the first connecting portion 221. The second connecting portion 222 and the first connecting portion 221 cooperate to form a groove 223. In this embodiment, by employing the first connecting portion 221 and the second connecting portion 222 in cooperation, not only can the protrusion 22 be formed, but it is also easier to process the protrusion 22, for example, by pressing an unprocessed current collector 2 to form the protrusion 22, and the overall weight of the protrusion 22 can also be reduced.

[0071] In some specific embodiments of the present invention, in the first direction, both sides of the second connecting portion 222 are planar, and the thickness of the second connecting portion 222 is 0.1mm-0.4mm. For example, the upper and lower sides of the second connecting portion 222 are both planar surfaces extending in the horizontal direction, and the thickness of the second connecting portion 222 is the distance between the upper and lower sides of the second connecting portion 222. In this embodiment, by limiting the thickness of the second connecting portion 222 to 0.1mm-0.4mm, for example, the thickness of the second connecting portion 222 is 0.1mm, 0.2mm, 0.3mm, or 0.4mm, the requirements of the laser thermal conductive welding process can be met. Furthermore, if the thickness of the original flat current collector 2 meets the requirement of producing a second connecting part 222 with a thickness of 0.1mm-0.4mm before manufacturing, the original thickness of the current collector 2 can be maintained; if the thickness of the second connecting part 222 produced from the original flat current collector 2 is greater than 0.1mm-0.4mm, at least a portion of the thickness of the flat current collector 2 can be reduced to the required thickness before processing such as embossing.

[0072] According to one embodiment of the present invention, the current collector 2 is the outer casing or current collector plate of a cylindrical battery. That is, the current collector 2 can be a separate current collector plate or the outer casing 4 of a cylindrical battery. When the current collector 2 is part of the outer casing 4 of a cylindrical battery, a protrusion 22 can be formed on a plane of the outer casing 4 during manufacturing. For example, the outer casing 4 of the cylindrical battery extends in the vertical direction, and the outer casing 4 is a cup-shaped piece with a receiving space and an open top. An upwardly extending protrusion 22 is embossed on the bottom of the outer casing 4, that is, protruding into the interior of the outer casing 4.

[0073] In some specific embodiments of the present invention, a body 21 may have multiple protrusions 22, which are spaced apart around a first direction; and / or, the outer contour of the protrusions 22 may be trapezoidal or rectangular, etc. When the outer contour is trapezoidal, the shorter side of the trapezoid is close to the central axis of the full-pole lug core; when the outer contour is rectangular, the two ends of the rectangle are straight or semi-circular sides. For example, a body 21 may have four protrusions 22 formed by downward pressing. The body 21 may be disc-shaped, and the four protrusions 22 may be spaced apart and evenly and symmetrically distributed around the central axis of the disc-shaped part. The cross-section of each protrusion 22 may be trapezoidal, with the shorter side close to the central axis of the disc-shaped part and the longer side away from the central axis of the disc-shaped part. As another example, the cross-section of the protrusion 22 may be elongated, with the two shorter sides being arc-shaped, and the center of the arc-shaped part being close to the central axis of the elongated part.

[0074] According to one embodiment of the present invention, the current collector 2 is a single piece. For example, before processing, the current collector 2 is a flat plate with both its upper and lower surfaces extending horizontally, and one or more downwardly protruding protrusions 22 are formed by pressing downwards. In this embodiment, by using a single piece for the current collector 2, it is not only easier to process the protrusions 22, but also the overall structural strength of the current collector 2 can be guaranteed.

[0075] In some specific embodiments of the present invention, the empty foil 121 having a second height includes: a first segment 1211 and a second segment 1212, the first segment 1211 extending along a first direction, the second segment 1212 extending along a second direction, and one end of the second segment 1212 being connected to the first segment 1211, the end face of the second segment 1212 in the first direction being connected to the surface of the protrusion 22 by laser thermal conductive welding.

[0076] In this embodiment, the empty foil 121 with a second height includes a first segment 1211 and a second segment 1212. Specifically, the second segment 1212 can be formed by bending. For example, during assembly, the protrusion 22 is pressed along the axial direction of the full-pole lug core, by means of... Figure 2 The compressive force in the direction of the arrow shown will bend part of the empty foil 121 to form a shape like... Figure 3 The second segment 1212 is shown. Furthermore, the first segment 1211 extends along a first direction, and the second segment 1212, after being bent, extends along a second direction; for example, the first segment 1211 extends vertically, and the second segment 1212 extends horizontally. In addition, the bent second segment 1212 has a larger surface area, which facilitates its fit with the surface of the protrusion 22 and allows for... Figure 4The solid inverted triangle shown indicates that laser heat conduction welding is performed, and the flatness of the surface corresponding to the protrusion 22 of the second segment 1212 formed by bending is relatively good. For example, the upper surface of the second segment 1212 is attached to the lower surface of the protrusion 22 and connected by laser heat conduction welding; or the lower surface of the second segment 1212 is attached to the upper surface of the protrusion 22 and connected by laser heat conduction welding. It can be understood that surface-to-surface contact is beneficial to improving the welding effect. In addition, by using bent hollow foil 121, the connection width between the electrode tab and the current collector 2 can be increased, thereby improving the current carrying capacity of the cell 1.

[0077] According to one embodiment of the present invention, in a first direction, the protrusion 22 has a height d, and in a second direction, there is a gap D between two adjacent layers of empty foil 121, where d > D. In this embodiment, by limiting the height of the protrusion 22 to be greater than the spacing between two adjacent layers of empty foil 121, it is advantageous to implement laser heat-conducting welding.

[0078] Optionally, the cylindrical battery also includes a top cover 3, which has an opening in the center and a terminal post riveted to the center of the opening. An insulating layer is provided between the terminal post and the cover to improve safety performance.

[0079] The present invention also provides a method for manufacturing a cylindrical battery, wherein the cylindrical battery is any of the cylindrical batteries described in the above embodiments, and the manufacturing method includes the following steps:

[0080] Along the first direction, a force is applied to the current collector 2 toward the empty foil portion 12, so that the empty foil 121 corresponding to the protrusion 22 has a second height after bending, and the protrusion 22 is attached to the end face of the empty foil portion 12.

[0081] The empty foil 121 with a second height is connected to the protrusion 22 by laser thermal welding.

[0082] As can be seen, this embodiment improves upon existing laser welding connection methods, resulting in less heat input during the welding process, less damage to the battery cell 1, and improved yield. Furthermore, by applying a force to the current collector 2 towards the empty foil portion 12, a portion of the empty foil portion 12 can be bent. Subsequently, the second segment 1212 formed after bending is laser-heat-conducted welded to the current collector 2, increasing the welding area and facilitating full contact with the end face of the protrusion 22, thus meeting the welding requirements for heat-conducting welding. Moreover, by bending the empty foil portion 12 by squeezing the current collector 2, one end of the empty foil portion 12 undergoes localized deformation, simplifying the electrode tab processing of the battery cell 1 and significantly improving production efficiency and product quality.

[0083] Furthermore, when the protrusion 22 is pressed toward the empty foil portion 12, part of the empty foil portion 12 corresponding to the protrusion 22 is bent; while another part of the empty foil portion 12 corresponding to the body 21 is not bent and can fit against the surface of the body 21.

[0084] In this embodiment, by improving the design of the current collector 2 and adapting it to the laser thermal conductive welding process, the additional processing of the exposed empty foil portion in the prior art is eliminated, which greatly simplifies the process and avoids the corresponding process risks.

[0085] The present invention also provides an electrical device comprising a cylindrical battery according to any of the above embodiments, or comprising a cylindrical battery prepared by the manufacturing method of the cylindrical battery according to any of the above embodiments. Since the cylindrical batteries of the present invention have advantages such as ease of processing and reduced damage to the winding core, the electrical device comprising the cylindrical battery according to any of the above embodiments also has the same advantages, which will not be elaborated upon here.

[0086] The cylindrical battery and its manufacturing method according to the present invention will be described in detail below with reference to specific embodiments.

[0087] Example

[0088] The cylindrical battery includes a casing 4, a cell 1, a current collector, and a top cover 3. The upper and lower ends of the cell 1 are empty foil portions 12. In this embodiment, a portion of the casing 4 and the current collector are current collectors 2.

[0089] Specifically, the outer casing 4 of the cylindrical battery extends in the vertical direction. The outer casing 4 is a cup-shaped piece with a receiving space and an open top. Four protrusions extending upward are imprinted on the bottom of the outer casing 4. The four protrusions are symmetrically distributed with the center of the bottom cover of the outer casing 4 as the center of symmetry.

[0090] The lower end face of the collector plate has four protrusions formed by embossing, and the four protrusions are evenly and symmetrically distributed with the center of the collector plate as the center of symmetry.

[0091] The assembly process includes the following steps:

[0092] S1. Press the current collector downward into the cell 1, and bend a portion of the empty foil portion 12 at the upper end of the positive electrode to form a second segment 1212 extending in the horizontal direction and a first segment 1211 extending in the vertical direction. The upper end face of the second segment 1212 is in contact with the lower end face of the boss at the lower end of the current collector, and the second segment 1212 of the positive electrode and the current collector are connected by laser thermal conductive welding, that is, the positive electrode tab and the current collector are connected.

[0093] S2. Weld the manifold and the top cover 3 together.

[0094] S3. Place the battery cell 2 inside the outer casing 4, press the protrusion on the bottom surface of the outer casing 4 upward into the lower end of the negative electrode sheet to form the second section 1212. Connect the second section 1212 of the negative electrode sheet and the outer casing 4 by laser thermal welding, that is, connect the negative electrode tab and the outer casing 4.

[0095] S4. Seal the top cover 3 and the outer shell 4 by laser welding to complete the assembly.

[0096] In summary, the cylindrical battery and its manufacturing method according to embodiments of the present invention, by setting an empty foil portion 12 with a height difference and a current collector 2 including a body 21 and a protrusion 22, and then adapting it to a corresponding laser thermal conductive welding process, realizes a full-tab battery design, which can significantly reduce the battery internal resistance with lower process difficulty, and also improve the overcurrent capacity. Furthermore, the local temperature of the welding area during laser thermal conductive welding is lower than that during penetration welding, thus causing less damage to the core.

[0097] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A cylindrical battery, characterized by comprising: The application relates to a cylindrical battery, which comprises: an electric core (1), which is a full-tab roll core with a central axis extending in a first direction, the full-tab roll core comprising a coated part (11) coated with active material and an empty-foil part (12) not coated with active material, the empty-foil part (12) being close to an outer edge of one end of the full-tab roll core in the first direction, the empty-foil part (12) comprising a plurality of empty-foil pieces (121) arranged adjacent to each other in a second direction, the second direction being arranged non-parallel to the first direction, in the first direction, a part of the empty-foil pieces (121) having a first height, and another part of the empty-foil pieces (121) having a second height, the first height being greater than the second height; a current collector (2), which comprises a body (21) and a protruding part (22) protruding from one side surface of the body (21); wherein the empty-foil pieces (121) having the first height are connected with the body (21), and the empty-foil pieces (121) having the second height are connected with the protruding part (22) through laser heat conduction welding.

2. The cylindrical battery according to claim 1, characterized by, The protruding part (22) comprises: a first connecting part (221) and a second connecting part (222), the first connecting part (221) being a ring-shaped piece, one end of the first connecting part (221) being connected with the body (21) in the first direction, and the second connecting part (222) being arranged to close the other end of the first connecting part (221), the second connecting part (222) and the first connecting part (221) cooperating to form a groove (223).

3. The cylindrical battery according to claim 2, characterized by, In the first direction, both side surfaces of the second connecting part (222) are flat surfaces, and the thickness of the second connecting part (222) is 0.1 mm-0.4 mm.

4. The cylindrical battery according to claim 1, characterized by, The current collector (2) is an outer shell or a current collecting disc of the cylindrical battery.

5. The cylindrical battery according to claim 1, wherein The number of the protruding parts (22) on one body (21) is multiple, and the multiple protruding parts (22) are distributed at intervals in the first direction; and / or the outer contour of the protruding part (22) is trapezoidal or rectangular, when the outer contour is trapezoidal, the short side of the trapezoid is close to the central axis of the full-tab roll core, and when the outer contour is rectangular, the two ends of the rectangle are straight edges or semicircular edges.

6. The cylindrical battery according to any one of claims 1 to 5, wherein The current collector (2) is an integral piece.

7. The cylindrical battery according to claim 1, wherein The empty-foil piece (121) having the second height comprises: a first segment (1211) extending in the first direction; a second segment (1212) extending in the second direction, one end of the second segment (1212) being connected with the first segment (1211) in the second direction, and the end surface of the second segment (1212) in the first direction being connected with the surface of the protruding part (22) through laser heat conduction welding.

8. The cylindrical battery of claim 1, wherein, In the first direction, the protruding part (22) has a height d, and in the second direction, the gap D between two adjacent layers of the empty-foil pieces (121) is smaller than d, i.e. d>D.

9. A method of manufacturing a cylindrical battery, characterized by, The cylindrical battery is the cylindrical battery according to any one of claims 1-8, and the manufacturing method comprises the following steps: In the first direction, the current collector (2) is applied to the action force towards the empty foil part (12), so that the empty foil (121) corresponding to the convex part (22) has a second height after bending, and the convex part (22) is attached to the end face of the empty foil part (12); The empty foil (121) with the second height is connected with the convex part (22) by laser heat conduction welding.

10. An electric device, characterized by The cylindrical battery comprises the cylindrical battery according to any one of claims 1-8, or the cylindrical battery prepared by the manufacturing method of the cylindrical battery according to claim 9.

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