Welding device and welding method

Abstract

The invention provides a welding device and a welding method, the welding device is used for welding a plurality of tabs and connecting pieces of a battery, the welding device comprises a first welding head, a second welding head, an ultrasonic generating device and a power source, and the first welding head and the second welding head are oppositely arranged and used for clamping the tabs and the connecting pieces; the power supply is electrically connected with the first welding head and the second welding head; in the working state, the tabs and the connecting pieces are clamped between the first welding head and the second welding head, and the ultrasonic generating device is used for generating ultrasonic waves and conducting the ultrasonic waves to the first welding head and / or the second welding head. The first welding head and the second welding head are electrically conducted through the plurality of tabs and the connecting sheet; the welding device disclosed by the invention can effectively ensure the contact between the multi-tab and the connecting sheet, and can improve the performance of the battery cell. In addition, the complex process that multiple tabs and connecting pieces need to be welded twice in an existing pole piece structure is optimized. According to the invention, the performance of the battery cell is improved, the time and labor cost of the production process are saved, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electrode ear welding, and in particular to a welding device and a welding method. Background Art As people's requirements for lithium battery charging speed continue to increase, the tabs of lithium batteries have also changed from single (one positive and one negative tab) to multiple (multiple positive and negative tabs). In order to ensure the normal performance of lithium batteries, the welding between the multiple tabs and the connecting piece must be firm and reliable during processing and manufacturing. There are two existing methods for welding multiple tabs to connecting pieces. Method 1: Use ultrasonic waves to pre-weld the multiple tabs, and then ultrasonically weld the multiple tabs to the connecting piece; Method 2: Directly weld the tabs to the connecting piece through a one-time ultrasonic welding.

[0002] The welding effect of scheme one is good, but the process is complicated, the equipment structure is complicated, the cost is high and the efficiency is low; the welding effect of scheme two is unstable, the welding energy is too large, which easily causes the topmost part of the pole ear to be welded broken; the welding energy is too small, and the bottommost part of the pole ear has a cold weld, etc. Therefore, how to overcome the above-mentioned technical problems and defects has become a key issue that needs to be solved. Summary of the invention

[0003] In view of the problem that the existing welding process of multiple tabs and connecting sheets is complicated or the welding effect is unstable, the present invention provides a welding device and a welding method.

[0004] The technical solution adopted by the present invention to solve the above technical problems is as follows: In one aspect, the present invention provides a welding device for welding a plurality of tabs and connecting pieces of a battery, the welding device comprising a first welding head, a second welding head, an ultrasonic generator and a power source, the first welding head and the second welding head being arranged opposite to each other and being used to clamp the plurality of tabs and the connecting pieces; the power source being electrically connected to the first welding head and the second welding head respectively; In the working state, the plurality of the pole lugs and the connecting pieces are clamped between the first welding head and the second welding head, and the ultrasonic generating device is used to generate ultrasonic waves and transmit them to the first welding head and / or the second welding head; the first welding head and the second welding head are electrically connected through the plurality of the pole lugs and the connecting pieces.

[0005] Optionally, the first welding head or the second welding head is connected to a driving unit, and under the drive of the driving unit, the first welding head or the second welding head moves toward the multiple pole tabs of the battery until the outermost connecting pieces and the pole tabs of the multiple pole tabs contact the first welding head and the second welding head respectively.

[0006] Optionally, the first welding head and the second welding head are respectively connected to a driving unit, and under the drive of the driving unit, the first welding head and the second welding head both move toward the multiple pole tabs of the battery until the outermost connecting pieces and the pole tabs of the multiple pole tabs contact the first welding head and the second welding head respectively.

[0007] Optionally, the number of the tabs is 18-22.

[0008] Optionally, the first welding head and the second welding head include a welding tooth area having multiple welding teeth, and multiple welding tooth arrays are arranged in the welding tooth area. The welding tooth includes a welding tooth body, a welding tooth head and a groove portion. The welding tooth body protrudes from the surface of the first welding head or the second welding head, and the groove portion is formed at the periphery of the end of the welding tooth body that contacts the first welding head or the second welding head, and the welding tooth head is formed at the end of the welding tooth body that contacts the pole ear.

[0009] Optionally, the groove portions between two adjacent welding teeth partially overlap, and the two adjacent welding teeth share the overlapping groove portions.

[0010] Optionally, the height of the welding teeth is 0.15mm-0.25mm.

[0011] Optionally, the groove portion is in a rhombus shape, the weld tooth head is in a rhombus shape, the four corners of the weld tooth head are connected to the four corners opposite to the groove portion via side edges, and the lengths of the four side edges are the same.

[0012] Optionally, the side length of the welding tooth head is 0.15mm-0.25mm, and the side length of the groove portion is 0.35mm-0.5mm.

[0013] In one aspect, the present invention provides a welding method, which uses the welding device described above to process a plurality of tabs, and the welding method comprises: S1. The plurality of tabs are stacked; S2. A connecting piece is provided on one side of the plurality of tabs close to the first welding head, and a portion of the connecting piece overlaps with a portion of the tab to form an overlapping area; S3. Electrically connect the first welding head and the second welding head to the power supply, use the welding tooth areas of the first welding head and the second welding head to clamp the overlapping areas of the plurality of the pole ears and the connecting plates, realize resistance welding of the overlapping areas through the power supply, and simultaneously start the ultrasonic generating device to synchronously perform ultrasonic welding on the overlapping areas to form welding tooth areas.

[0014] Optionally, the length of the weld tooth area is 7.9 mm-8.1 mm; the width of the weld tooth area is 2.9 mm to 3.1 mm.

[0015] Optionally, the first welding head is connected to the positive electrode of the power supply, the second welding head is connected to the negative electrode of the power supply, the current passing through the first welding head is 10-15KA, and the current passing through the second welding head is 10-15KA.

[0016] Optionally, the welding temperature of the first welding head is 80-270°C; the welding temperature of the second welding head is 80-270°C.

[0017] Optionally, the ultrasonic amplitude of the first welding head is 45-70%; the ultrasonic amplitude of the second welding head is 45-70%.

[0018] Optionally, the welding time of the first welding head is 0.5-2s; the welding time of the second welding head is 0.5-2s.

[0019] Optionally, the welding pressure of the first welding head is 5-10Mpa; the welding pressure of the second welding head is 5-10Mpa.

[0020] According to the welding device and welding method provided by the present invention, the first welding head and the second welding head of the present invention can simultaneously perform ultrasonic welding and resistance welding on multiple pole tabs and connecting sheets when powered on, combining ultrasonic welding and resistance welding into one; compared with the existing pole tab welding technology, the welding device of the present invention can effectively ensure the contact between multiple pole tabs and connecting sheets, and can improve the performance of the battery cell. Moreover, the present invention optimizes the complex process of welding multiple pole tabs and connecting sheets twice in the existing pole sheet structure. While improving the performance of the battery cell, the present invention also saves time and labor costs in the production process and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 is a schematic structural diagram of a welding device provided by an embodiment of the present invention; Figure 2 It is a schematic structural diagram of a welding tooth region of a welding head provided by an embodiment of the present invention; Figure 3 is a schematic structural diagram of a welding tooth provided by an embodiment of the present invention; The reference numerals in the drawings of the specification are as follows: 1-first welding head; 2-second welding head; 3-power supply; 4-battery; 41-ear; 42-connecting piece; 5-welding tooth area; 51-welding tooth; 511-welding tooth body; 512-welding tooth head; 513-groove part. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] like Figure 1 As shown, in one embodiment, the present invention provides a welding device for welding a plurality of tabs 41 and a connecting piece 42 of a battery 4, the welding device comprising a first welding head 1, a second welding head 2, an ultrasonic generating device (not shown in the figure) and a power source 3, the first welding head 1 and the second welding head 2 are arranged opposite to each other, and are used to clamp a plurality of tabs 41 and a connecting piece 42; the power source 3 is electrically connected to the first welding head 1 and the second welding head 2 respectively; In the working state, multiple pole ears 41 and connecting plates 42 are clamped between the first welding head 1 and the second welding head 2, and the ultrasonic generating device is used to generate ultrasonic waves and transmit them to the first welding head 1 and / or the second welding head 2; the first welding head 1 and the second welding head 2 are electrically connected through the multiple pole ears 41 and connecting plates 42.

[0027] In the working state, at least one end of the battery 4 is provided with a plurality of pole ears 41, and the plurality of pole ears 41 are stacked on one side of the connecting piece 42, and the plurality of pole ears 41 and the connecting piece 42 are clamped between the first welding head 1 and the second welding head 2, and the first welding head 1 and the second welding head 2 are both electrically connected to the power supply 3, and the first welding head 1 and the second welding head 2 are started by the power supply 3 to realize resistance welding of the overlapping area, and at the same time, the overlapping area is ultrasonically welded by the ultrasonic generating device; thereby, the first welding head 1 and the second welding head 2 of the present application have both ultrasonic welding function and resistance welding function; the plurality of pole ears 41 and the connecting piece 42 are welded once by the first welding head 1 and the second welding head 2 to realize the connection of the plurality of pole ears 41 and the connecting piece 42.

[0028] Specifically, multiple pole tabs 41 are stacked, and a connecting piece 42 is provided on one side of the multiple pole tabs 41 close to the first welding head 1. The length direction of the connecting piece 42 is parallel to the length direction of the multiple pole tabs 41, and the width direction of the connecting piece 42 is parallel to the width direction of the multiple pole tabs 41. In the direction perpendicular to the thickness of the pole tab 41, a partial projection of the connecting piece 42 overlaps with a partial area of ​​the pole tab 41 to form an overlapping area. The first welding head 1 and the second welding head 2 contact the multiple pole tabs 41 and the connecting piece 42, and weld the multiple pole tabs 41 and the connecting piece 42 together.

[0029] When powered on, the first welding head 1 and the second welding head 2 of the present application can simultaneously perform ultrasonic welding and resistance welding on multiple pole tabs 41 and connecting pieces 42, combining ultrasonic welding and resistance welding into one; compared with the existing pole tab 41 welding technology, the welding device of the present invention can effectively ensure the contact between multiple pole tabs 41 and connecting pieces 42, and can improve the performance of the battery cell. Moreover, the present invention optimizes the complex process of welding multiple pole tabs 41 and connecting pieces 42 twice in the existing pole piece structure. While improving the performance of the battery cell, the present invention also saves time and labor costs in the production process and improves production efficiency.

[0030] like Figure 1 As shown, in one embodiment, the first welding head 1 or the second welding head 2 is connected to a driving unit, and under the drive of the driving unit, the first welding head 1 or the second welding head 2 moves toward the multiple pole tabs 41 of the battery 4 until the outermost connecting pieces 42 and the pole tabs 41 of the multiple pole tabs 41 contact the first welding head 1 and the second welding head 2 respectively.

[0031] In one embodiment, a driving unit is connected to one side of the first welding head 1. Driven by the driving unit, the first welding head 1 moves downward until the first welding head 1 contacts the connecting piece 42, multiple pole tabs 41 and the second welding head 2. The first welding head 1 and the second welding head 2 simultaneously perform ultrasonic welding and resistance welding on the multiple pole tabs 41 and the connecting piece 42, which can effectively ensure the contact between the multiple pole tabs 41 and the connecting piece 42, improve the performance of the battery cell, save time and labor costs in the production process, and improve production efficiency.

[0032] In another embodiment, a driving unit is connected to one side of the second welding head 2. Driven by the driving unit, the second welding head 2 moves upward until the second welding head 2 contacts the connecting piece 42, multiple pole tabs 41 and the first welding head 1. The first welding head 1 and the second welding head 2 simultaneously perform ultrasonic welding and resistance welding on the multiple pole tabs 41 and the connecting piece 42, which can effectively ensure the contact between the multiple pole tabs 41 and the connecting piece 42, improve the performance of the battery cell, save time and labor costs in the production process, and improve production efficiency.

[0033] The driving unit in the present application is a mechanism in the prior art that can drive the first welding head 1 or the second welding head 2 to move up or down, including a motor, a cylinder and other mechanisms. Since these are components of the prior art, their structure is not limited and protected by this patent, so they are not described in detail here.

[0034] like Figure 1 As shown, in one embodiment, the first welding head 1 and the second welding head 2 are respectively connected to a driving unit. Driven by the driving unit, the first welding head 1 and the second welding head 2 both move toward the multiple pole tabs 41 of the battery 4 until the outermost connecting pieces 42 and the pole tabs 41 of the multiple pole tabs 41 contact the first welding head 1 and the second welding head 2 respectively.

[0035] In a preferred embodiment, one side of the first welding head 1 is connected to a driving unit a, and one side of the second welding head 2 is connected to a driving unit b. Driven by the driving unit a, the first welding head 1 moves downward, and driven by the driving unit b, the second welding head 2 moves upward until the first welding head 1 contacts the connecting piece 42, multiple pole tabs 41 and the second welding head 2. The first welding head 1 and the second welding head 2 simultaneously perform ultrasonic welding and resistance welding on the multiple pole tabs 41 and the connecting piece 42, which can effectively ensure the contact between the multiple pole tabs 41 and the connecting piece 42, improve the performance of the battery cell, save time and labor costs in the production process, and improve production efficiency.

[0036] like Figure 1 As shown, in one embodiment, the number of the tabs 41 is 18-22.

[0037] Specifically, the number of the tabs 41 is any one of 18, 19, 20, 21 or 22, or a range consisting of any two values; in a preferred embodiment, the number of the tabs 41 is 19-21.

[0038] like Figure 2-Figure 3 As shown, in one embodiment, the first welding head 1 and the second welding head 2 include a welding tooth area 5 having a plurality of welding teeth 51, and the plurality of welding teeth 51 are arranged in an array in the welding tooth area 5, and the welding tooth 51 includes a welding tooth body 511, a welding tooth head 512 and a groove portion 513, and the welding tooth body 511 is protruding from the surface of the first welding head 1 or the second welding head 2, and the groove portion 513 is formed on the periphery of the end of the welding tooth body 511 that contacts the first welding head 1 or the second welding head 2, and the welding tooth head 512 is formed on the end of the welding tooth body 511 that contacts the pole ear.

[0039] Specifically, the weld tooth area 5 is rectangular, and the weld tooth area 5 is respectively arranged at the welding ends of the first welding head 1 and the second welding head 2; in the direction parallel to the thickness of the electrode lug, the projection of the weld tooth area 5 at the welding end of the first welding head 1 at the welding end of the second welding head 2 overlaps with the weld tooth area 5 at the welding end of the second welding head 2. Thus, when welding the electrode lug, the forces on both sides are balanced.

[0040] During welding, the present application has multiple welding tooth heads 512 first contact the surface of the pole ear, and under high temperature, the contact portion of the connecting piece with the welding tooth head 512 of the first welding head 1 is dissolved, and the contact portion of the pole ear close to the second welding head 2 with the welding tooth head 512 of the second welding head 2 is dissolved, and the dissolved connecting piece portion flows along the welding tooth body 511 to the groove portion 513 on the surface of the first welding head 1; the dissolved pole ear portion flows along the welding tooth body 511 to the groove portion 513 on the surface of the second welding head 2 and fills the groove portion 513, thereby improving the surface flatness of the connecting piece and the pole ear, and improving the welding strength between the connecting piece and the pole ear.

[0041] like Figure 2-Figure 3 As shown, in one embodiment, the groove portions 513 between two adjacent welding teeth 51 partially overlap, and the two adjacent welding teeth 51 share the overlapping groove portions 513 .

[0042] Specifically, the groove portion 513 can be square, annular, diamond or other shapes; there is a partial overlap between the groove portions 513 of two adjacent welding teeth 51, and the two adjacent welding teeth 51 share the overlapping groove portions 513, so that all the groove portions 513 on the surface of the first welding head 1 are connected; and / or, all the groove portions 513 on the surface of the second welding head 2 are connected, so as to avoid excessive dissolved liquid in some groove portions 513, overflow, and reflux to the connecting plate or the pole ear surface under uneven heating or uneven force, resulting in low surface flatness of the connecting plate and the pole ear, affecting the welding strength between the connecting plate and the pole ear.

[0043] like Figure 2-Figure 3 As shown, in one embodiment, the height of the welding tooth 51 is 0.15 mm-0.25 mm.

[0044] Specifically, the height of the welding tooth 51 is any value among 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, and 0.25mm, or a range value consisting of any two values; in a preferred embodiment, the height of the welding tooth 51 is 0.18mm-0.22mm.

[0045] When the height of the welding teeth 51 is 0.15 mm-0.25 mm, the welding strength of the electrode tab can be guaranteed, and the adverse effects such as over-welding or cold welding on the electrode tab can be avoided.

[0046] like Figure 1 As shown, in one embodiment, the shape of the groove portion 513 is a rhombus, the shape of the welding tooth head 512 is a rhombus, the four corners of the welding tooth head 512 and the four corners opposite to the groove portion 513 are connected by side edges, and the lengths of the four side edges are the same.

[0047] In a preferred embodiment, the groove portion 513 is square in shape, the weld tooth head 512 is square in shape, and the weld tooth 51 is a quadrangular pyramid. Compared with the diamond-shaped weld tooth head 512, the square weld tooth head 512 can increase the contact area with the connecting piece or the pole ear and increase the welding strength.

[0048] In a more preferred embodiment, the groove portion 513 is in the shape of a ring, the weld tooth head 512 is in the shape of a square, and the weld tooth 51 is in the shape of a cone, thereby maximizing the contact area with the connecting piece or the pole ear and increasing the welding strength; and when the connecting piece or the pole ear is dissolved, the path length of the groove portion 513 flowing along the weld tooth body 511 to the surface of the welding head is equal, thereby maximizing the surface flatness of the connecting piece and the pole ear and improving the welding strength between the connecting piece and the pole ear.

[0049] like Figure 1 As shown, in one embodiment, the side length of the welding tooth head 512 is 0.15 mm-0.25 mm, and the side length of the groove portion 513 is 0.35 mm-0.5 mm.

[0050] Specifically, the side length of the welding tooth head 512 is any value among 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, and 0.25mm, or a range value consisting of any two values; in a preferred embodiment, the side length of the welding tooth head 512 is 0.18mm-0.22mm.

[0051] Specifically, the side length of the groove portion 513 is any value among 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.44mm, 0.43mm, 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm or 0.5mm, or a range value consisting of any two values; in a preferred embodiment, the side length of the groove portion 513 is 0.38mm-0.44mm.

[0052] When the side length of the welding tooth head 512 is 0.15mm-0.25mm and the side length of the groove portion 513 is 0.35mm-0.5mm, it can not only ensure the welding strength of the pole ear, but also allow the liquid after the connecting piece or the pole ear is dissolved to flow completely to the groove portion 513 on the surface of the welding head, thereby improving the surface flatness of the connecting piece and the pole ear and improving the welding strength between the connecting piece and the pole ear.

[0053] In one aspect, the present invention provides a welding method, which uses the above-mentioned welding device to process a plurality of tabs 41, and the welding method comprises: S1. The plurality of tabs 41 are stacked; S2. A connecting piece 42 is provided on one side of the plurality of tabs 41 close to the first welding head 1, and a portion of the connecting piece 42 overlaps with a portion of the tab 41 to form an overlapping region; S3. Electrically connect the first welding head 1 and the second welding head 2 to the power supply 3, use the welding tooth area 5 of the first welding head 1 and the second welding head 2 to clamp the overlapping area of ​​the multiple pole ears 41 and the connecting plate 42, realize resistance welding of the overlapping area through the power supply 3, and start the ultrasonic generating device at the same time to synchronously perform ultrasonic welding on the overlapping area to form the welding tooth area 5.

[0054] Specifically, multiple pole ears 41 are stacked, and in the direction perpendicular to the thickness of the pole ears 41, the projections of the multiple pole ears 41 overlap; a connecting piece 42 is provided on one side of the multiple pole ears 41 close to the first welding head 1, and the length direction of the connecting piece 42 is parallel to the length direction of the multiple pole ears 41, and the width direction of the connecting piece 42 is parallel to the width direction of the multiple pole ears 41, and in the direction perpendicular to the thickness of the pole ears 41, a partial projection of the connecting piece 42 overlaps with a partial area of ​​the pole ears 41 to form an overlapping area.

[0055] When the first welding head 1 and the second welding head 2 of the present application are powered on, resistance welding can be performed on multiple pole tabs 41 and connecting pieces 42. At the same time, the ultrasonic generator is started to synchronously perform ultrasonic welding on the overlapping areas. The welding method of the present invention can effectively ensure the contact between the multiple pole tabs 41 and the connecting pieces 42, and can improve the performance of the battery cell. Moreover, the present invention optimizes the complex process of welding the multiple pole tabs 41 and the connecting pieces 42 twice in the existing pole piece structure. While improving the performance of the battery cell, the present invention also saves time and labor costs in the production process and improves production efficiency.

[0056] like Figure 2 As shown, in one embodiment, the length of the weld tooth area 5 is 7.9 mm-8.1 mm; the width of the weld tooth area 5 is 2.9 mm to 3.1 mm.

[0057] Specifically, the length of the weld tooth area 5 is any value among 7.9mm, 7.91mm, 7.92mm, 7.93mm, 7.94mm, 7.95mm, 7.96mm, 7.97mm, 7.98mm, 7.99mm, 8mm, 8.01mm, 8.02mm, 8.03mm, 8.04mm, 8.05mm, 8.06mm, 8.07mm, 8.08mm, 8.09mm, and 8.1mm, or a range value consisting of any two values; in a preferred embodiment, the length of the weld tooth area 5 is 8mm.

[0058] like Figure 2 As shown, in one embodiment, the first welding head 1 and the second welding head 2 include a welding tooth area 5 having a plurality of welding teeth 51. After the first welding head 1 and the second welding head 2 clamp the overlapping area of ​​the plurality of pole tabs 41 and the connecting piece 42, the welding tooth area 5 of the first welding head 1 and the welding tooth area 5 of the first welding head 2 perform resistance welding and ultrasonic welding on the overlapping area to form the welding tooth area 5.

[0059] Specifically, the weld tooth regions 5 are symmetrically arranged in the length direction of the multiple pole lugs, and the weld tooth regions 5 are symmetrically arranged in the width direction of the multiple pole lugs.

[0060] Specifically, the width of the weld tooth area 5 is 2.9mm, 2.91mm, 2.92mm, 2.93mm, 2.94mm, 2.95mm, 2.96mm, 2.97mm, 2.98mm, 2.99mm, 3mm, 3.01mm, 3.02mm, 3.03mm, 3.04mm, 3.05mm, 3.06mm, 3.07mm, 3.08mm, 3.09mm, and 3.1mm, or a range value consisting of any two of the values; in a preferred embodiment, the width of the weld tooth area 5 is 3mm.

[0061] Specifically, the width of the connecting piece 42 is 5-6 mm; the width of the pole lug 41 is 6-7 mm; when the connecting piece 42 and the pole lug 41 are overlapped, along the width direction of the pole lug 41, the distance between the first end of the connecting piece 42 and the first end of the pole lug 41 is 0.5-1 mm; the distance between the second end of the connecting piece 42 and the second end of the pole lug 41 is 0.5-1 mm.

[0062] When the width of the connecting piece 42 is 5-6mm, the width of the pole ear 41 is 6-7mm, the length of the welding tooth area 5 is 7.9mm-8.1mm; when the width of the welding tooth area 5 is 2.9mm~3.1mm, the technical effects of reliable positioning, reliable welding, large welding area and large current carrying can be achieved.

[0063] like Figure 1 As shown, in one embodiment, the first welding head 1 is connected to the positive electrode of the power supply 3, the second welding head 2 is connected to the negative electrode of the power supply 3, the current passing through the first welding head 1 is 10-15KA, and the current passing through the second welding head 2 is 10-15KA.

[0064] Specifically, the current passed through the first welding head 1 is any value among 10KA, 10.5KA, 11KA, 11.5KA, 12KA, 12.5KA, 13KA, 13.5KA, 14KA, 14.5KA, and 15KA, or a range value consisting of any two values; in a preferred embodiment, the current passed through the first welding head 1 is 11-14KA.

[0065] Specifically, the current passed through the second welding head 2 is any value among 10KA, 10.5KA, 11KA, 11.5KA, 12KA, 12.5KA, 13KA, 13.5KA, 14KA, 14.5KA, and 15KA, or a range value consisting of any two values; in a preferred embodiment, the current passed through the second welding head 2 is 11-14KA.

[0066] When the current passed by the first welding head 1 is 10-15KA, the arc is stable and the penetration depth and width are stable and reliable; when the current passed by the first welding head 1 is less than 10KA, the arc will be unstable and the penetration depth will be small, which may easily cause false welding; when the current passed by the first welding head 1 is greater than 15KA, the arc will increase, the penetration depth will increase, and over-welding will occur.

[0067] When the current passed by the second welding head 2 is 10-15KA, the arc is stable and the penetration depth and width are stable and reliable; when the current passed by the second welding head 2 is less than 10KA, the arc will be unstable and the penetration depth will be small, which may easily cause false welding; when the current passed by the second welding head 2 is greater than 15KA, the arc will increase, the penetration depth will increase, and over-welding will occur.

[0068] like Figure 1As shown, in one embodiment, the welding temperature of the first welding head 1 is 80-270°C; the welding temperature of the second welding head 2 is 80-270°C.

[0069] Specifically, the welding temperature of the first welding head 1 is 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C or 270°C, or a range value consisting of any two values; in a preferred embodiment, the welding temperature of the first welding head 1 is 150-200°C.

[0070] When the welding temperature of the first welding head 1 is 200-270°C, the technical effect of stable penetration depth and width and reliable welding is achieved; when the welding temperature of the first welding head 1 is less than 200°C, the penetration depth will become shallow, resulting in a cold weld; when the welding temperature of the first welding head 1 is greater than 270°C, the penetration depth will be too deep, resulting in over-welding.

[0071] Specifically, the welding temperature of the second welding head 2 is any value of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C or 270°C, or a range value consisting of any two values; in a preferred embodiment, the welding temperature of the second welding head 2 is 150-200°C.

[0072] When the welding temperature of the second welding head 2 is 200-270°C, the technical effect of stable penetration depth and width and reliable welding is achieved; when the welding temperature of the second welding head 2 is less than 200°C, the penetration depth will become shallow, resulting in a cold weld; when the welding temperature of the second welding head 2 is greater than 270°C, the penetration depth will be too deep, resulting in over-welding.

[0073] In other embodiments, when the first welding head 1 and / or the second welding head 2 welds the positive electrode tab, the welding temperature is 80-120°C; when the first welding head 1 and / or the second welding head 2 welds the negative electrode tab, the welding temperature is 200-270°C.

[0074] like Figure 1 As shown, in one embodiment, the ultrasonic amplitude of the first welding head 1 is 45-70%; the ultrasonic amplitude of the second welding head 2 is 45%-70%.

[0075] Specifically, the ultrasonic amplitude of the first welding head 1 is any value of 45%, 50%, 55%, 60%, 65%, 70%, or a range value consisting of any two values; in a preferred embodiment, the ultrasonic amplitude of the first welding head 1 is 50%-60%.

[0076] Specifically, the ultrasonic amplitude of the second welding head 2 is any value of 45%, 50%, 55%, 60%, 65%, 70%, or a range value consisting of any two values; in a preferred embodiment, the ultrasonic amplitude of the second welding head 2 is 50%-60%.

[0077] When the ultrasonic amplitude of the first welding head 1 is 50%-60%, it has the technical effect of high welding strength and reliable welding; when the ultrasonic amplitude of the first welding head 1 is less than 50%, it will lead to reduced energy transmission and cause cold welding; when the ultrasonic amplitude of the first welding head 1 is greater than 60%, it will lead to excessive energy output and cause over-welding.

[0078] When the ultrasonic amplitude of the second welding head 2 is 50%-60%, it has the technical effect of high welding strength and reliable welding; when the ultrasonic amplitude of the second welding head 2 is less than 50%, it will lead to reduced energy transmission and cause cold welding; when the ultrasonic amplitude of the second welding head 2 is greater than 60%, it will cause excessive energy output and cause over-welding.

[0079] like Figure 1 As shown, in one embodiment, the welding time of the first welding head 1 is 0.5-2 s; the welding time of the second welding head 2 is 0.5-2 s.

[0080] Specifically, the welding time of the first welding head 1 is any value among 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s, 1.6s, 1.7s, 1.8s, 1.9s, and 2s, or a range value consisting of any two values; in a preferred embodiment, the welding time of the first welding head 1 is 0.9-1.3s.

[0081] Specifically, the welding time of the second welding head 2 is any value among 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s, 1.6s, 1.7s, 1.8s, 1.9s, and 2s, or a range value consisting of any two values; in a preferred embodiment, the welding time of the second welding head 2 is 0.9-1.3s.

[0082] When the welding time of the first welding head 1 is 0.5-2s, it has the technical effect of fully solidifying the welding point and improving the welding quality; when the welding time of the first welding head 1 is less than 0.5s, the welding point will not be fully solidified, resulting in a cold weld; when the welding time of the first welding head 1 is greater than 2s, the solidified welding point will be damaged, resulting in over-welding.

[0083] When the welding time of the second welding head 2 is 0.5-2s, the welding point is fully solidified and the welding quality is improved; when the welding time of the second welding head 2 is less than 0.5s, the welding point will not be fully solidified, resulting in a cold weld; when the welding time of the second welding head 2 is greater than 2s, the solidified welding point will be damaged, resulting in over-welding.

[0084] like Figure 1 As shown, in one embodiment, the welding pressure of the first welding head 1 is 5-10 MPa; the welding pressure of the second welding head 2 is 5-10 MPa.

[0085] Specifically, the welding pressure of the first welding head 1 is any value among 5Mpa, 5.5Mpa, 6Mpa, 6.5Mpa, 7Mpa, 7.5Mpa, 8Mpa, 8.5Mpa, 9Mpa, 9.5Mpa, and 10Mpa, or a range value consisting of any two values; in a preferred embodiment, the welding pressure of the first welding head 1 is 7-9Mpa.

[0086] Specifically, the welding pressure of the second welding head 2 is any value among 5Mpa, 5.5Mpa, 6Mpa, 6.5Mpa, 7Mpa, 7.5Mpa, 8Mpa, 8.5Mpa, 9Mpa, 9.5Mpa, and 10Mpa, or a range value consisting of any two values; in a preferred embodiment, the welding pressure of the second welding head 2 is 7-9Mpa.

[0087] When the welding pressure of the first welding head 1 is 5-10Mpa, it has the technical effect of ensuring that the welding point is still under pressure after formation, thereby reducing the possibility of loosening or falling off of the welding point; when the welding pressure of the first welding head 1 is less than 5Mpa, it will lead to insufficient pressure, loosening or falling off of the welding point, resulting in a cold weld; when the welding pressure of the first welding head 1 is greater than 10Mpa, it will lead to excessive pressure, the molten pool cannot be fused, the welding point will loosen or fall off, resulting in a cold weld.

[0088] When the welding pressure of the second welding head 2 is 5-10Mpa, it has the technical effect of ensuring that the welding point is still under pressure after formation, reducing the possibility of loosening or falling off of the welding point; when the welding pressure of the second welding head 2 is less than 5Mpa, it will lead to insufficient pressure, loosening or falling off of the welding point, resulting in a cold weld; when the welding pressure of the second welding head 2 is greater than 10Mpa, it will lead to excessive pressure, the molten pool cannot be fused, the welding point will loosen or fall off, resulting in a cold weld.

[0089] The preparation method and application of the present invention will be further described in detail below in conjunction with specific examples. It should be understood that the following examples are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0090] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0091] Example 1 This embodiment is used to illustrate the welding method disclosed in the present invention, which includes the following steps: S1. Stacking multiple tabs; S2. A connecting piece is provided on one side of the plurality of tabs close to the first welding head, and a portion of the connecting piece overlaps with a portion of the tab to form an overlapping area; S3. Electrically connect the first welding head and the second welding head to the power supply, and use the first welding head and the second welding head to simultaneously perform ultrasonic welding and resistance welding on the overlapping areas of multiple pole ears and connecting plates, wherein the ultrasonic amplitude is 56%; the current is 12KA, the welding pressure is 8.0Mpa, and the welding time is 1.1s; and the multiple pole ears and connecting plates are fixedly connected after one welding.

[0092] Comparative Example 1 This embodiment is used to illustrate the welding method disclosed in the present invention, which includes the following steps: S1. Stacking multiple tabs; S2. A connecting piece is provided on one side of the plurality of tabs close to the first welding head, and a portion of the connecting piece overlaps with a portion of the tab to form an overlapping area; S3. In the absence of power, ultrasonic welding is performed simultaneously on the overlapping areas of multiple pole tabs and connecting sheets using the first welding head and the second welding head, wherein the ultrasonic amplitude is 70%; the welding pressure is 9.1 MPa, and the welding time is 1.5 s; and multiple pole tabs and connecting sheets are fixedly connected after one welding.

[0093] Comparative Example 2 This embodiment is used to illustrate the welding method disclosed in the present invention, which includes the following steps: S1. Stacking multiple tabs; S2. In the absence of power, use the first welding head and the second welding head to simultaneously perform ultrasonic welding on the overlapping areas of multiple tabs and connecting sheets, wherein the ultrasonic amplitude is 10%; the welding pressure is 3.5 MPa, and the welding time is 0.5; and the first pre-welding of multiple tabs is performed.

[0094] S3. A connecting piece is provided on one side of the plurality of tabs close to the first welding head, and a portion of the connecting piece overlaps with a portion of the tab to form an overlapping area; S4. In the absence of power, ultrasonic welding is performed simultaneously on the overlapping areas of multiple pole tabs and connecting sheets using the first welding head and the second welding head, wherein the ultrasonic amplitude is 65%; the welding pressure is 8.6 MPa, and the welding time is 1.2 s; and the multiple pole tabs and connecting sheets are fixedly connected after one final welding.

[0095] Performance Test: The following performance tests were performed on the tabs and connecting pieces prepared by the above welding method: 1. Welding tensile test: The electrode tabs and connecting sheets welded in Example 1 and Comparative Examples 1-2 were cut into the same length, width and shape, and marked.

[0096] 2. Welding quality test: The test adopts static tensile test, and the force is evenly applied by electronic tensile tester. The sample is stably fixed at both ends of the fixture assembly and stretched in one direction until the sample breaks, and the tensile data is recorded.

[0097] The results are shown in Table 1.

[0098] Table 1 Test results obtained from Example 1 and Comparative Examples 1-2 It can be seen from the test results in Table 1 that, by comparing Example 1 with Comparative Example 1, when ultrasonic welding and resistance welding are simultaneously performed on multiple tabs and connecting sheets, the tension and welding quality between the tabs and the connecting sheets can be improved; although Comparative Example 1 is also only welded once, the tension and welding quality between the tabs and the connecting sheets are relatively low; By comparing Example 1 with Comparative Example 2, it can be seen that after two weldings, the tension between the tab and the connecting sheet and the welding rate of Comparative Example 2 are both higher, but the welding process is complicated, the welding time is long, and the efficiency is low; The present invention combines ultrasonic welding and resistance welding into one, which has the advantages of small ultrasonic amplitude, small pressure, short welding time, high efficiency, high tensile strength, high quality rate, and only one welding is performed, so that the first welding head and the second welding head have less wear, longer service life, and high cost performance.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A welding device for welding multiple tabs and connecting pieces of a battery, characterized in that: The welding device comprises a first welding head, a second welding head, an ultrasonic generator and a power source, wherein the first welding head and the second welding head are arranged opposite to each other and used for clamping the plurality of the tabs and the connecting sheet; the power source is electrically connected to the first welding head and the second welding head respectively; In the working state, the plurality of the pole lugs and the connecting pieces are clamped between the first welding head and the second welding head, and the ultrasonic generating device is used to generate ultrasonic waves and transmit them to the first welding head and / or the second welding head; the first welding head and the second welding head are electrically connected through the plurality of the pole lugs and the connecting pieces.

2. The welding device according to claim 1, characterized in that: The first welding head or the second welding head is connected to a driving unit. Driven by the driving unit, the first welding head or the second welding head moves toward the multiple pole tabs of the battery until the outermost connecting piece and the pole tab of the multiple pole tabs contact the first welding head and the second welding head respectively.

3. The welding device according to claim 1, characterized in that: The first welding head and the second welding head are respectively connected to a driving unit. Under the drive of the driving unit, the first welding head and the second welding head move toward the multiple pole tabs of the battery until the outermost connecting piece and the pole tab of the multiple pole tabs contact the first welding head and the second welding head respectively.

4. The welding device according to claim 1, characterized in that: The number of the tabs is 18-22.

5. The welding device according to claim 4, characterized in that: The first welding head and the second welding head include a welding tooth area having a plurality of welding teeth, and a plurality of welding tooth arrays are arranged in the welding tooth area. The welding tooth includes a welding tooth body, a welding tooth head and a groove portion. The welding tooth body protrudes from the surface of the first welding head or the second welding head, and the groove portion is formed at the periphery of one end of the welding tooth body in contact with the first welding head or the second welding head, and the welding tooth head is formed at one end of the welding tooth body in contact with the pole ear.

6. The welding device according to claim 5, characterized in that: The groove portions between two adjacent welding teeth partially overlap, and the two adjacent welding teeth share the overlapping groove portions.

7. The welding device according to claim 5, characterized in that: The height of the welding teeth is 0.15mm-0.25mm.

8. The welding device according to claim 5, characterized in that: The groove portion is in a rhombus shape, the welding tooth head is in a rhombus shape, the four corners of the welding tooth head are connected to the four corners opposite to the groove portion through side edges respectively, and the lengths of the four side edges are the same.

9. The welding device according to claim 5, characterized in that: The side length of the welding tooth head is 0.15mm-0.25mm, and the side length of the groove portion is 0.35mm-0.5mm.

10. A welding method, characterized in that: A plurality of tabs are processed using the welding device according to any one of claims 1 to 9, the welding method comprising: S1. The plurality of tabs are stacked; S2. A connecting piece is provided on one side of the plurality of tabs close to the first welding head, and a portion of the connecting piece overlaps with a portion of the tab to form an overlapping area; S3. Electrically connect the first welding head and the second welding head to the power supply, use the welding tooth areas of the first welding head and the second welding head to clamp the overlapping areas of the plurality of the pole ears and the connecting plates, realize resistance welding of the overlapping areas through the power supply, and simultaneously start the ultrasonic generating device to synchronously perform ultrasonic welding on the overlapping areas to form welding tooth areas.

11. The welding method according to claim 10, characterized in that: The length of the welding tooth area is 7.9 mm-8.1 mm; the width of the welding tooth area is 2.9 mm-3.1 mm.

12. The welding method according to claim 10, characterized in that: The first welding head is connected to the positive electrode of the power supply, and the second welding head is connected to the negative electrode of the power supply. The current passing through the first welding head is 10-15KA, and the current passing through the second welding head is 10-15KA.

13. The welding method according to claim 10, characterized in that: The welding temperature of the first welding head is 80-270°C; the welding temperature of the second welding head is 80-270°C.

14. The welding method according to claim 10, characterized in that: The ultrasonic amplitude of the first welding head is 45-70%; the ultrasonic amplitude of the second welding head is 45-70%.

15. The welding method according to claim 10, characterized in that: The welding time of the first welding head is 0.5-2s; the welding time of the second welding head is 0.5-2s.

16. The welding method according to claim 10, characterized in that: The welding pressure of the first welding head is 5-10Mpa; the welding pressure of the second welding head is 5-10Mpa.

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