power battery

Abstract

This application discloses a power battery, including a core, a casing, a top cover, terminals, a first current collector, a second current collector, and a side welding ring. The outer periphery of the core protrudes upwards to form a metal foil protrusion, which is spaced apart from the first full-face tab. The metal foil protrusion is formed by a multi-turn winding structure of a second electrode sheet. The side welding ring includes two opposing side walls, which are fitted onto the metal foil protrusion, with the side walls clamping the protrusion between them. The top cover forms an annular downward protrusion near its outer edge. The outer side of the annular downward protrusion and the inner side wall of the side welding ring are attached and welded by laser penetration welding. This application allows for the same-end lead-out of the positive and negative electrodes, avoiding series connection to the casing resistance, and has a large welding area, thereby reducing the power battery resistance, enabling high-rate charging and discharging of the power battery, reducing temperature rise, and improving the safety of the power battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a power battery. Background Technology

[0002] Currently, lithium-ion / sodium-ion cylindrical power batteries are gradually becoming the mainstream product in the new energy industry due to their advantages such as high energy density, good capacity consistency, and ability to support high-rate charge and discharge. However, the top cover structure of cylindrical power batteries presents the following technical challenges:

[0003] After the current collector is welded onto the bare cells (cores) of conventional cylindrical power batteries, they are directly inserted into the casing and assembled with resistance welding or laser penetration welding. The welding area is relatively small, and the positive and negative electrodes of the battery are connected in series with the casing resistor, resulting in a relatively large resistance value of the cylindrical power battery. This makes it difficult to achieve high-rate charging and discharging, and the temperature rise is also relatively large.

[0004] A few manufacturers have begun to explore the sidewall welding assembly of cylindrical power battery current collectors into the casing, that is, laser welding of the current collector to the casing wall. Because the casing wall is relatively thin, it is easy to weld through the casing wall or make a false weld, resulting in a lot of welding defects. Summary of the Invention

[0005] The purpose of this application is to provide a power battery that can solve at least one of the technical problems in the background art.

[0006] To achieve the above objectives, this application provides a power battery, including a core, a casing, a top cover, terminals, a first current collector, a second current collector, and a side welding ring. The casing is fitted around the outside of the core, and the top cover is fitted over the upper opening of the casing. Terminals are mounted on the top cover, and the terminals are insulated from the top cover. A first full electrode tab is formed at the top of the core, which is formed by a first electrode sheet. A metal foil protrusion is formed on the outer periphery of the core, and the metal foil protrusion is spaced apart from the first full electrode tab. The metal foil protrusion is formed by the upward protrusion of a multi-turn winding structure of the second electrode sheet. A second electrode is formed at the bottom of the core. Two full-pole tabs, the second full-pole tab being formed by the second electrode plate, one of the first electrode plate and the second electrode plate being a positive electrode plate and the other being a negative electrode plate, the first current collector being welded between the first full-pole tab and the electrode post, the second current collector being welded between the second full-pole tab and the bottom of the housing, the side welding ring including two opposing side walls, the side welding ring being sleeved on the metal foil protrusion, wherein the two side walls of the side welding ring clamp the metal foil protrusion therebetween, the top cover forming an annular downward protrusion near its outer edge, the outer side surface of the annular downward protrusion and the inner side wall of the side welding ring being attached and welded by laser penetration welding.

[0007] Optionally, the first current collector is a positive current collector, and the second current collector is a negative current collector.

[0008] Optionally, the metal foil protrusions are provided with a plurality of stress relief notches distributed along their circumference.

[0009] Optionally, the upper ends of the two side walls of the side welding ring are connected by a connecting wall, and the two side walls and the connecting wall of the side welding ring are respectively formed with multiple hollow grooves.

[0010] Optionally, the outer sidewall of the side weld ring extends downward beyond the inner sidewall of the side weld ring.

[0011] Optionally, the cross-section of the annular convex shape is U-shaped.

[0012] Optionally, the thickness of the annular convex protrusion is greater than the thickness of the sidewall of the housing.

[0013] Optionally, the bottom of the annular convex shape is provided with an insulating element.

[0014] Optionally, the upper ends of the two side walls of the side welding ring are connected by a connecting wall, the bottom edge of the top cover is pressed against the connecting wall of the side welding ring, and the upper end of the outer edge of the top cover protrudes outward with an annular overlapping portion, which overlaps with the top surface of the side wall of the housing and is laser welded.

[0015] Optionally, the first collector includes a main body and an extension extending from the main body. The main body is welded to the first full-tab region. After the pole is welded to the extension, the top cover is flipped over to bend the extension upward. The annular downwardly convex outer side is adapted to fit against the inner sidewall of the side welding ring.

[0016] In this embodiment, the outer periphery of the core protrudes upward to form a metal foil protrusion. This metal foil protrusion is formed by the multi-turn winding structure of the second electrode sheet. A side welding ring is fitted onto the metal foil protrusion, with its two side walls sandwiching the protrusion. A top cover forms an annular downward protrusion near its outer edge. The outer side of the annular downward protrusion and the inner side wall of the side welding ring are attached and welded together by laser penetration welding. This allows the positive and negative electrodes to be led out from the same end, avoiding series connection of the casing resistance. Furthermore, because the outer side of the annular downward protrusion and the inner side wall of the side welding ring are attached and welded by laser penetration welding, a large welding area is achieved, which reduces the resistance of the power battery, enabling high-rate charging and discharging of the power battery and reducing temperature rise, thus improving the safety of the power battery. Attached Figure Description

[0017] Figure 1 This is a cross-sectional structural diagram of the power battery according to an embodiment of this application.

[0018] Figure 2 yes Figure 1 Enlarged view of part A in the middle.

[0019] Figure 3 This is a cross-sectional structural diagram of the power battery according to an embodiment of this application, in which the casing is hidden.

[0020] Figure 4 yes Figure 3 Enlarged view of section B in the middle.

[0021] Figure 5 This is a three-dimensional structural diagram of the core of an embodiment of this application.

[0022] Figure 6 This is a three-dimensional structural schematic diagram of the core from another perspective of an embodiment of this application.

[0023] Figure 7 This is a three-dimensional structural schematic diagram of the side welding ring according to an embodiment of this application.

[0024] Figure 8 This is a cross-sectional structural diagram of the side welding ring in an embodiment of this application. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] Please see Figures 1 to 8This application discloses a power battery, including a core 10, a housing 20, a top cover 30, terminals 40, a first current collector 50, a second current collector 60, and a side welding ring 70. The housing 20 is sleeved on the outside of the core 10, and the top cover 30 is provided at the top opening of the housing 20. Terminals 40 are mounted on the top cover 30, and the terminals 40 and the top cover 30 are insulated. A first full electrode tab 11 is formed at the top of the core 10, which is formed by a first electrode sheet. A metal foil protrusion 12 is formed by the outer periphery of the core 10 protruding upward, and the metal foil protrusion 12 is spaced apart from the first full electrode tab 11. The metal foil protrusion 12 is formed by the upward protrusion of a multi-turn winding structure of a second electrode sheet. A second full electrode tab 13 is formed at the bottom of the core 10, which is formed by a second electrode sheet. One of the first electrode and the second electrode is a positive electrode and the other is a negative electrode. The first current collector 50 is welded between the first full electrode tab 11 and the electrode post 40. The second current collector 60 is welded between the second full electrode tab 13 and the bottom 21 of the housing 20. The side welding ring 70 includes two opposing side walls 71 and 72. The side welding ring 70 is sleeved on the metal foil protrusion 12, wherein the two side walls 71 and 72 of the side welding ring 70 sandwich the metal foil protrusion 12 therebetween (the two side walls 71 and 72 of the side welding ring 70 are in contact with the outermost and innermost ring structures of the metal foil protrusion 12, respectively). The top cover 30 forms an annular lower protrusion 31 near its outer edge. The outer side of the annular lower protrusion 31 and the inner side wall 72 of the side welding ring 70 are attached and welded by laser penetration welding.

[0027] The explanation of the first and second electrodes is as follows: The core 10 is formed by winding a positive electrode, a negative electrode, and a separator, etc. One of the first and second electrodes is the positive electrode, and the other is the negative electrode. After winding the core 10, at least a portion of the first electrode in the middle region at the top of the core 10 protrudes upward to form an untreated first full electrode tab 11, and at least a portion of the second electrode protrudes downward to form an untreated second full electrode tab 13. Then, the first full electrode tab 11 and the second full electrode tab 13 are flattened / patted flat.

[0028] It should be explained that the shell bottom 21 of the shell 20 should be interpreted in a broad sense. It can be either the shell bottom 21 formed together with the shell side wall 22, or a cover assembled to the shell side wall 22. In this case, the shell 20 can be a structure with openings at both ends.

[0029] In this embodiment, the outer periphery of the core 10 protrudes upward to form a metal foil protrusion 12. The metal foil protrusion 12 is formed by the multi-turn winding structure of the second electrode sheet. A side welding ring 70 is fitted onto the metal foil protrusion 12. The two side walls 71 and 72 of the side welding ring 70 sandwich the metal foil protrusion 12 between them. The top cover 30 forms an annular lower protrusion 31 near its outer edge. The outer side of the annular lower protrusion 31 and the inner side wall 72 of the side welding ring 70 are attached and welded by laser penetration welding. This allows the positive and negative electrodes to be led out from the same end, avoiding the resistance of the housing 20 in series. Furthermore, since the outer side of the annular lower protrusion 31 and the inner side wall 72 of the side welding ring 70 are attached and welded by laser penetration welding, they have a large welding area, which can reduce the resistance of the power battery, enable high-rate charging and discharging of the power battery, reduce temperature rise, and improve the safety of the power battery.

[0030] Specifically, the core 10 is cylindrical, but is not limited to this.

[0031] In some embodiments, the first current collector 50 is a positive current collector, and the second current collector 60 is a negative current collector.

[0032] Specifically, the first collector plate 50 is made of aluminum, and the second collector plate 60 is made of copper or nickel, etc.

[0033] Specifically, the first electrode is made of aluminum, and the second electrode is made of copper.

[0034] In some embodiments, the metal foil protrusion 12 has a plurality of stress relief notches 121 distributed along its circumference to relieve stress and ensure the reliability of the structure.

[0035] In some embodiments, the upper ends of the two side walls 71, 72 of the side welding ring 70 are connected by a connecting wall 73.

[0036] Specifically, the cross-section of the side weld ring 70 is roughly U-shaped.

[0037] Specifically, the two side walls 71, 72 and the connecting wall 73 of the side welding ring 70 are each formed with a plurality of hollow grooves 74. Since the two side walls 71, 72 and the connecting wall 73 of the side welding ring 70 are each formed with a plurality of hollow grooves 74, bending can be assisted and stress can be released during side welding of the top cover 30, so that the welded parts can fit better and ensure welding consistency.

[0038] In some embodiments, the outer sidewall 71 of the side weld ring 70 extends downward beyond the inner sidewall 72 of the side weld ring 70. Since the inner sidewall 72 of the side weld ring 70 faces downward towards the core 10, it needs to be spaced from the end face of the core 10. However, the outer sidewall 71 of the side weld ring 70 does not have this limitation, thus allowing the outer sidewall 71 to extend downward beyond its inner sidewall 72. This arrangement improves the reliability of the structural assembly.

[0039] In some embodiments, the cross-section of the annular lower protrusion 31 is U-shaped. In order to process the annular lower protrusion 31, a corresponding annular groove 32 is formed on the upper side of the top cover 30, which extends to the annular lower protrusion 31, so that the cross-section of the annular lower protrusion 31 is U-shaped.

[0040] Of course, the annular convex 31 is not limited to having a U-shaped cross section, as long as it can be side-welded with the side welding ring 70.

[0041] In some embodiments, the thickness of the annular lower protrusion 31 is greater than the thickness of the housing sidewall 22. Since the thickness of the annular lower protrusion 31 is greater than the thickness of the housing sidewall 22, the annular lower protrusion 31 can be prevented from being welded through during laser penetration welding of the opposite welding ring 70 and the annular lower protrusion 31, thereby avoiding the risk of leakage and poor welding.

[0042] For power batteries, the overall thickness of the top cover 30 is usually significantly greater than the thickness of the housing sidewall 22, so it is easy to process an annular downward protrusion 31 with a thickness greater than that of the housing sidewall 22 on the top cover 30.

[0043] It should be explained that when the cross-section of the annular lower protrusion 31 is U-shaped or similar, the thickness of the annular lower protrusion 31 refers to the thickness of the portion directly welded to the side welding ring 70.

[0044] In some embodiments, the bottom of the annular lower protrusion 31 is provided with an insulating member 80. Because the bottom of the annular lower protrusion 31 is provided with an insulating member 80, it can be ensured that the annular lower protrusion 31 will not make electrical contact with the structure below.

[0045] Specifically, the annular lower protrusion 31 is generally platform-shaped, and the insulating component 80 is attached to the bottom surface of the annular lower protrusion 31.

[0046] In a specific example, the insulating element 80 is attached to the inner wall of the top cover 30, and the outer area of ​​the insulating element 80 is adapted to be bent and extended to be attached to the bottom surface of the annular protrusion 31.

[0047] In some embodiments, the upper ends of the two side walls 71 and 72 of the side welding ring 70 are connected by a connecting wall 73. The bottom edge of the top cover 30 is pressed onto the connecting wall 73 of the side welding ring 70. The upper end of the outer edge of the top cover 30 protrudes outward with an annular overlapping portion 33, which overlaps with the top surface of the housing side wall 22 and is laser welded. This arrangement improves the stability of the assembly.

[0048] In some embodiments, the first collector plate 50 includes a main body 51 and an extension 52 extending from the main body 51. The main body 51 is welded to the first full electrode tab 11. After the electrode post 40 is welded to the extension 52, the top cover 30 is flipped so that the extension 52 bends upward, and the outer side of the annular downward protrusion 31 is adapted to fit against the inner side wall 72 of the side welding ring 70. Of course, this application is not limited to this structural form and assembly method. For example, in some other embodiments, the top cover 30 may also be placed directly downward so that the outer side of the annular downward protrusion 31 is adapted to fit against the inner side wall 72 of the side welding ring 70.

[0049] In some embodiments, the bottom 21 of the housing 20 is provided with an injection hole 211, through which electrolyte can be injected after the main body of the power battery is assembled.

[0050] To facilitate understanding of this application, the specific assembly process of the power battery is described below based on examples in the accompanying drawings. This should not be construed as a limitation of this application.

[0051] First, a core 10 is formed by winding. A first full-pole tab 11 and a metal foil protrusion 12 are formed at the top of the core 10, and a second full-pole tab 13 is formed at the bottom of the core 10. Then, the first full-pole tab 11 and the second full-pole tab 13 are flattened / patted, and multiple stress relief notches 121 are processed in the metal foil protrusion 12.

[0052] Next, the first collector plate 50 is welded to the first full tab 11 by laser penetration welding, and the second collector plate 60 is welded to the second full tab 13 by laser penetration welding.

[0053] Next, the side welding ring 70 is placed on the metal foil protrusion 12 with its opening facing downwards. The two side walls 71 and 72 of the side welding ring 70 clamp the two sides of the metal foil protrusion 12, which can achieve large-area contact.

[0054] Next, the pole 40 of the top cover assembly (including top cover 30, pole 40, insulating part 80, etc.) is welded to the extension 52. Then, the top cover assembly is flipped over so that the extension 52 is bent upward and the outer side of the annular protrusion 31 is adapted to fit against the inner side wall 72 of the side welding ring 70.

[0055] Next, laser penetration welding is performed from the outside of the side welding ring 70 to weld the side welding ring 70 and the outer surface of the annular lower protrusion 31 together.

[0056] Next, the assembled assembly is placed into the housing 20, with the second manifold 60 facing the bottom 21 of the housing, and the annular overlapping portion 33 of the top cover 30 overlapping the top surface of the side wall 22 of the housing and laser-welded to seal it.

[0057] Next, liquid is injected through the injection hole 211 at the bottom of the shell 21, and then the injection hole 211 is sealed using a sealing pin (not shown).

[0058] The above-disclosed examples are merely preferred embodiments of this application, intended to facilitate understanding and implementation by those skilled in the art. They should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the scope of this application are still within the scope of this application.

Claims

1. A power battery, characterized in that, The device includes a core, a housing, a top cover, poles, a first current collector, a second current collector, and side welding rings. The housing is fitted around the outside of the core, and the top cover is fitted over the upper opening of the housing. Poles are mounted on the top cover, and the poles are insulated from the top cover. A first full-pole tab is formed at the top of the core, which is formed by a first electrode sheet. A metal foil protrusion is formed on the outer periphery of the core, and the metal foil protrusion is spaced apart from the first full-pole tab. The metal foil protrusion is formed by a multi-turn winding structure of a second electrode sheet. A second full-pole tab is formed at the bottom of the core. The ear is formed by the second electrode plate, one of the first electrode plate and the second electrode plate is a positive electrode plate and the other is a negative electrode plate. The first current collector is welded between the first full electrode ear and the pole post. The second current collector is welded between the second full electrode ear and the bottom of the housing. The side welding ring includes two opposing side walls. The side welding ring is sleeved on the metal foil protrusion. The two side walls of the side welding ring sandwich the metal foil protrusion therebetween. The top cover forms an annular downward protrusion near its outer edge. The outer side of the annular downward protrusion and the inner side wall of the side welding ring are attached and welded by laser penetration welding.

2. The power battery according to claim 1, characterized in that, The first current collector is a positive current collector, and the second current collector is a negative current collector.

3. The power battery according to claim 1, characterized in that, The metal foil protrusions have multiple stress relief notches distributed along their circumference.

4. The power battery according to claim 1, characterized in that, The upper ends of the two side walls of the side welding ring are connected by a connecting wall, and the two side walls and the connecting wall of the side welding ring are respectively formed with multiple hollow grooves.

5. The power battery according to claim 1, characterized in that, The outer sidewall of the side weld ring extends downward beyond the inner sidewall of the side weld ring.

6. The power battery according to claim 1, characterized in that, The annular downward convex cross-section is U-shaped.

7. The power battery according to claim 1 or 6, characterized in that, The thickness of the annular convex shape is greater than the thickness of the sidewall of the housing.

8. The power battery according to claim 1 or 6, characterized in that, An insulating element is provided at the bottom of the annular convex shape.

9. The power battery according to claim 1, characterized in that, The upper ends of the two side walls of the side welding ring are connected by a connecting wall. The bottom edge of the top cover is pressed against the connecting wall of the side welding ring. The upper end of the outer edge of the top cover protrudes outward into an annular overlapping part. The annular overlapping part overlaps the top surface of the side wall of the housing and is laser welded.

10. The power battery according to claim 1, characterized in that, The first collector includes a main body and an extension extending from the main body. The main body is welded to the first full-tab region. After the pole post is welded to the extension, the top cover is flipped over so that the extension bends upward. The annular downwardly convex outer side is adapted to fit against the inner side wall of the side welding ring.

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