Cylindrical battery collector plate welding structure

Abstract

The utility model relates to the technical field of cylindrical batteries, and discloses a cylindrical battery collector plate welding structure which comprises a roll core and a pole piece foil material, the pole piece foil material is wound to form the roll core, die cutting gaps are arranged at two ends of the pole piece foil material, tabs are formed on two sides of the die cutting gaps at two ends of the pole piece foil material, hollow collector plates are arranged on the outer sides of the tabs, and the hollow collector plates are arranged on the outer sides of the hollow collector plates. The hollow collector plate is arranged below the tab, the tab is arranged in the hollow collector plate, a tab passing hole is formed in the hollow collector plate and located on the outer side of the tab, the tab comprises a welding part and a connecting part, the part, located below the hollow collector plate, of the tab is the connecting part, and the part, located above the hollow collector plate, of the tab is the welding part. The risk that the laser penetrates through the foil and the hollowed-out collector plate and penetrates through the roll core diaphragm can be greatly reduced; in the rubbing process of the tabs, fallen metal filings can be intercepted by the hollowed-out collector plates, and the risk that the metal filings fall into the roll core to cause short circuit of the roll core is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of cylindrical batteries, in particular to a cylindrical battery collector plate welding structure. Background Art

[0002] In the battery manufacturing process, the collector plate is an important component of the battery, which is responsible for collecting and conducting current. The collector plate is used to connect the collector plate of the battery with the battery pole by laser welding. The collector plate welding structure in the prior art is as follows Figure 1 As shown, the cylindrical battery is made into a core 4 by winding the internal positive electrode sheet, negative electrode sheet and diaphragm. The core 4 is cylindrical and has a through hole in the center of the core 4. For large cylindrical batteries (outer diameter ≥ 32mm), the two ends of the core 4 are metal foils 3 with the positive and negative pole pieces leaking out. Generally, different metal current collecting plates 2 are used to weld the metal foils 3 at both ends to lead out the positive and negative poles. The metal current collecting plate 2 is connected to the metal foil 3 on the positive and negative pole pieces of the core by melting the welding point 5 using the laser device transmitter 1. After assembly and electrical activation, the battery can be put into use normally. During use, the negative electrode releases electrons, enters the positive electrode through an external circuit, and generates electricity to the outside.

[0003] At present, the commonly used collector plate welding structure is that after the pole piece is wound into a winding core 4, the metal foil 3 at both ends of the winding core is bent and flattened by the equipment flattening mechanism under high-speed rotation, and then the metal collector plate 2 and the metal foil 3 are welded together by the laser equipment transmitter 1. The laser equipment transmitter 1 first penetrates the metal collector plate 2, and melts the welding points 5 in the welding area of ​​the metal collector plate 2 through continuous high-energy laser. Under the metal heat conduction effect, the metal foil 3 on the bottom side of the metal collector plate 2 is also melted. When the laser equipment transmitter 1 finishes welding, the welding points 5 in the melting area are mixed and solidified, so that the metal collector plate 2 is connected with the metal foil 3. By melting the welding points 5 in many welding areas on the metal collector plate 2, a firm welding is achieved.

[0004] However, there may be a phenomenon of cold welding between the collector plate and the foil during laser welding. Since the process of using the foil at the bottom and the collector plate at the top is adopted, the single-layer foil is thinner by about 0.006-0.015mm, and the collector plate is thicker by about 0.2-0.3mm. The laser energy may be insufficient, causing the upper collector plate welding point area to melt, while the lower foil is not melted or not fully melted;

[0005] In addition, after the foil on the electrode is flattened, the thickness of the foil stack is uneven. In some areas, the foil stack is very thin or even has gaps. When welding with the current collecting plate, the high laser energy may cause the current collecting plate to melt and produce holes. The laser directly penetrates the foil below or even directly into the winding core, causing damage to the diaphragm and a short circuit in the battery.

[0006] Moreover, metal chips are prone to fall off during the flattening process of the foil on the electrode. Since the bottom of the foil directly adheres to the top of the winding core, these metal chips will enter the winding core and cause an internal short circuit in the battery cell.

[0007] During the charging and discharging process of the battery cell, the heat generated by the current collector can easily cause the diaphragm to shrink, and may even cause a short circuit between the current collector and the foil contacting the electrode. Utility Model Content

[0008] The purpose of the utility model is to provide a cylindrical battery collector plate welding structure to solve the problems raised in the above background technology.

[0009] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a cylindrical battery collector disk welding structure, comprising: a winding core and a pole piece foil, the pole piece foil is wound to form a winding core, die-cut gaps are provided at both ends of the pole piece foil, pole ears are formed on both sides of the die-cut gaps at both ends of the pole piece foil, a hollow collector disk is provided on the outside of the pole ear, and a pole ear passing hole is provided inside the hollow collector disk on the outside of the pole ear, the pole ear comprises a welding portion and a connecting portion, the portion of the pole ear located below the hollow collector disk is the connecting portion, and the portion of the pole ear located above the hollow collector disk is the welding portion, the welding portion and the connecting portion are L-shaped, and the welding portion is fixed to the hollow collector disk by bending to the top of the hollow collector disk and welding.

[0010] Furthermore, the bending direction of the welding portion is toward the center of the hollow collecting plate.

[0011] Furthermore, an insulating thermally conductive silicone is provided on the bottom surface of the hollow current collecting disk, and the insulating thermally conductive silicone is used for heat conduction and insulation between the hollow current collecting disk and the tab foil.

[0012] Furthermore, a positioning hole is provided on the circumferential outer wall of the hollow collecting disk, and the positioning hole is used for grasping and positioning the hollow collecting disk.

[0013] Furthermore, there are a plurality of pole lugs and a plurality of pole lug passage holes, and the plurality of pole lugs correspond one to one with the plurality of pole lug passage holes.

[0014] Furthermore, the hollow collecting plate is made of conductive metal.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] The utility model realizes that when the cylindrical battery collector plate welding structure is used, the pole piece foil is die-cut and cut off, and the remaining part of the pole piece foil becomes the pole piece. The size of the pole piece and the size of the die-cutting gap are adjusted according to the different outer diameters of the battery. After the pole piece foil is wound into a winding core, the hollow collector plate is made of metal, and a layer of insulating thermal conductive silicone is coated on the back of the hollow collector plate. Positioning holes are designed on the edge of the hollow collector plate for the robot to position and accurately place it above the winding core. The die-cut pole piece passes through the hollow collector plate through the position of the pole piece through the hole, and then the welding part of the pole piece is bent by a flattening process so that the welding part is attached to the welding position on the top of the hollow collector plate, and the pole piece and the hollow collector plate are welded and connected by laser welding.

[0017] The entire collector plate welding structure has a welding part located above the hollow collector plate. During welding, the laser incident side is the pole ear of the pole piece foil, which is thinner, while the bottom is the hollow collector plate, which is thicker. During the welding process, the foil and the collector plate can be connected with lower laser power and welding time.

[0018] In addition, the design of the hollow collector plate at the bottom and the welding part of the pole ear at the top can greatly reduce the risk of laser penetrating the foil and the hollow collector plate and penetrating the core diaphragm;

[0019] Because the hollow collector plate is at the bottom and the welding part of the tab is at the top, the metal shavings that fall from the tab during the flattening process will be intercepted by the hollow collector plate, avoiding the risk of metal shavings falling into the winding core and causing a short circuit in the winding core;

[0020] The hollow collector plate and the specially designed die-cut foil ear shape ensure the electrolyte permeability. The thermally conductive insulating silicone coated on the back of the collector plate can, on the one hand, dissipate the heat generated by the hollow collector plate. At the same time, the hollow collector plate will not cause internal short circuit problems in the battery due to contact with the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a cylindrical battery collector plate welding structure in the prior art;

[0022] Figure 2 This is a three-dimensional diagram of a cylindrical battery collector plate welding structure of the utility model;

[0023] Figure 3 It is a schematic diagram of the unfolded state of the pole piece foil material of the cylindrical battery collector plate welding structure of the utility model;

[0024] Figure 4 It is a schematic diagram of the winding state of the pole piece foil material of a cylindrical battery collector plate welding structure of the utility model;

[0025] Figure 5It is a schematic diagram of a hollow current collecting disc structure of a cylindrical battery current collecting disc welding structure of the utility model.

[0026] In the figure: 1. Laser device transmitter; 2. Metal collector plate; 3. Metal foil; 4. Winding core; 5. Welding point; 6. Hollow collector plate; 7. Positioning hole; 8. Pole ear; 9. Pole ear through hole; 10. Pole piece foil; 11. Die-cut gap. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0028] See also Figure 2-Figure 5 The utility model provides a technical solution: a cylindrical battery collector disk welding structure, comprising: a winding core 4 and a pole piece foil 10, the pole piece foil 10 is wound to form the winding core 4, die-cut gaps 11 are provided at both ends of the pole piece foil 10, and pole ears 8 are formed on both sides of the die-cut gaps 11 at both ends of the pole piece foil 10, a hollow collector disk 6 is provided on the outside of the pole ear 8, and a pole ear through hole 9 is provided inside the hollow collector disk 6 on the outside of the pole ear 8, the pole ear 8 includes a welding portion and a connecting portion, the portion of the pole ear 8 located below the hollow collector disk 6 is the connecting portion, and the portion of the pole ear 8 located above the hollow collector disk 6 is the welding portion, the welding portion and the connecting portion are L-shaped, and the welding portion is fixed to the hollow collector disk 6 by being bent to the top of the hollow collector disk 6 and welded. The joint is located above the hollow collecting disk 6. During welding, the laser entrance side is the pole ear 8 of the pole piece foil 10, which is relatively thin, while the bottom is the hollow collecting disk 6, which is relatively thick. During the welding process, the foil and the collecting disk can be connected with lower laser power and welding time; the risk of laser penetrating the foil and the hollow collecting disk 6 and penetrating the core diaphragm can be greatly reduced; any metal chips dropped from the pole ear 8 during the flattening process will be intercepted by the hollow collecting disk 6, avoiding the risk of metal chips falling into the core 4 and causing the core 4 to short-circuit.

[0029] The bending direction of the welding part is toward the center of the hollow collecting plate 6, which avoids the welding parts of the pole lug 8 from overlapping each other, ensures the contact area between the welding part and the hollow collecting plate 6, thereby shortening the conduction distance of the pole lug 8, improving the current transmission efficiency of the battery and reducing the internal resistance.

[0030] The bottom surface of the hollow current collecting plate 6 is provided with insulating thermally conductive silicone, which is used for heat conduction and insulation between the hollow current collecting plate 6 and the tab foil 10 .

[0031] Positioning holes 7 are provided on the circumferential outer wall of the hollow collecting disc 6 . The positioning holes 7 are used for grabbing and positioning the hollow collecting disc 6 . The positioning holes 7 are semicircular. There are three positioning holes 7 . The three positioning holes 7 are evenly arranged circumferentially on the outer side of the hollow collecting disc 6 .

[0032] There are several pole lugs 8 and several pole lug through holes 9, and the several pole lugs 8 correspond to the several pole lug through holes 9. The size of the pole lug 8 and the size of the die-cutting gap 11 are adjusted according to the different outer diameters of the battery, and are suitable for batteries of various outer diameters.

[0033] The hollow collecting plate 6 is made of conductive metal to ensure that the battery current can be efficiently transmitted.

[0034] When the cylindrical battery collector plate welding structure is used, the pole piece foil 10 is die-cut and cut off, and the remaining part of the pole piece foil 10 becomes the pole ear 8. The size of the pole ear 8 and the size of the die-cutting gap 11 are adjusted according to the different outer diameters of the battery. After the pole piece foil 10 is wound into a winding core 4, the hollow collector plate 6 is made of metal, and a layer of insulating thermal conductive silicone is coated on the back of the hollow collector plate 6. A positioning hole 7 is designed on the edge of the hollow collector plate 6 for the robot to accurately position it on the top of the winding core 4. The die-cut pole ear 8 passes through the hollow collector plate 6 through the pole ear through hole 9, and then the welding part of the pole ear 8 is bent by a flattening process, so that the welding part is attached to the welding position on the top of the hollow collector plate 6, and the pole ear 8 and the hollow collector plate 6 are welded and connected by laser welding;

[0035] The entire collector plate welding structure has a welding portion located above the hollow collector plate 6. During welding, the laser incident side is the pole ear 8 of the pole piece foil 10, which is thinner, while the hollow collector plate 6 is thicker below. During the welding process, the foil and the collector plate can be connected with lower laser power and welding time.

[0036] In addition, the design of the hollow collector plate 6 at the bottom and the welding part of the pole ear 8 at the top can greatly reduce the risk of laser penetrating the foil and the hollow collector plate 6 and penetrating the core diaphragm;

[0037] Because the hollow collector plate 6 is at the bottom and the welding part of the pole ear 8 is at the top, the metal shavings dropped from the pole ear 8 during the flattening process will be intercepted by the hollow collector plate 6, avoiding the risk of metal shavings falling into the winding core 4 and causing the winding core 4 to short-circuit;

[0038] The hollow collecting disc 6 and the specially designed die-cut foil ear shape ensure the electrolyte permeability. The thermally conductive insulating silicone coated on the back of the collecting disc can, on the one hand, conduct the heat generated by the hollow collecting disc 6 away. At the same time, the hollow collecting disc 6 will not cause internal short circuit problems in the battery due to contact with the pole piece.

[0039] Based on the embodiments of the present utility model, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present utility model.

Claims

1. A cylindrical battery collector plate welding structure, comprising: A winding core (4) and a pole piece foil (10), characterized in that: the pole piece foil (10) is wound to form a winding core (4), a die-cut gap (11) is provided at both ends of the pole piece foil (10), pole ears (8) are formed on both sides of the die-cut gap (11) at both ends of the pole piece foil (10), a hollow collector disk (6) is provided on the outside of the pole ear (8), and a pole ear through hole (9) is provided inside the hollow collector disk (6) and located on the outside of the pole ear (8), and the pole ear (8) includes a welding portion and a connecting portion, the portion of the pole ear (8) located below the hollow collector disk (6) is the connecting portion, and the portion of the pole ear (8) located above the hollow collector disk (6) is the welding portion, the welding portion and the connecting portion are L-shaped, and the welding portion is welded and fixed to the hollow collector disk (6) by bending to the top of the hollow collector disk (6).

2. A cylindrical battery collector plate welding structure according to claim 1, characterized in that: The bending direction of the welding portion faces the center of the hollow current collecting plate (6).

3. A cylindrical battery collector plate welding structure according to claim 1, characterized in that: The bottom surface of the hollow current collecting disk (6) is provided with insulating thermally conductive silica gel, and the insulating thermally conductive silica gel is used for heat conduction and insulation between the hollow current collecting disk (6) and the tab foil (10).

4. A cylindrical battery collector plate welding structure according to claim 1, characterized in that: The circumferential outer wall of the hollow current collecting plate (6) is provided with a positioning hole (7), and the positioning hole (7) is used for grasping and positioning the hollow current collecting plate (6).

5. A cylindrical battery collector plate welding structure according to claim 1, characterized in that: There are a plurality of pole lugs (8), and a plurality of pole lug through holes (9), and the plurality of pole lugs (8) correspond one to one with the plurality of pole lug through holes (9).

6. A cylindrical battery collector plate welding structure according to claim 1, characterized in that: The hollow current collecting plate (6) is made of conductive metal.

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