Laser welding cooling device

Abstract

The present invention belongs to the field of laser welding technology, and discloses a laser welding cooling device. The laser welding cooling device is arranged between a laser emitter and a workpiece to be welded, and comprises a heat conductive block, the bottom of which is in contact with the workpiece to be welded, the heat conductive block is provided with a laser through hole for the laser of the laser emitter to pass through, and the thermal conductivity of the heat conductive block is higher than the thermal conductivity of the workpiece to be welded. The laser welding cooling device can reduce the heat generated when welding a battery and a busbar, thereby improving the safety during welding and the performance of the battery product.

Description

Technical Field

[0001] The invention relates to the technical field of laser welding, and in particular to a laser welding cooling device. Background Art

[0002] When welding the busbars of the single cell and the module of the square aluminum shell battery, the high temperature caused by laser welding often causes the battery to produce obvious gas swelling, and has a certain impact on the diaphragm and electrical performance. In comparison, the above phenomenon is more obvious when the full-ear battery is laser welded, and the lower the battery capacity, the more serious this situation is. In the prior art, when laser welding the busbar, only a protective gas is set to prevent the explosion during battery welding, and an inert compressed gas is used to purge the busbar surface to clean the welding slag. However, in the actual application of busbar welding, there is usually only the first purge, and there is no treatment measure for the heat generated by the welding, and the risk of welding slag during the welding process is also difficult to avoid. And as the design capacity of the battery decreases, the volume of the pole and the aluminum shell also becomes smaller, and the high temperature caused by welding is more harmful, and may even cause damage to the battery pole diaphragm or direct explosion, seriously affecting the performance evaluation of the battery product.

[0003] Therefore, there is an urgent need to provide a laser welding cooling device to solve the above-mentioned technical problems in the prior art. Summary of the invention

[0004] The object of the present invention is to provide a laser welding cooling device, which can reduce the heat generated when welding a battery and a bus bar, thereby improving the safety of welding and the performance of the battery product.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The laser welding cooling device is arranged between the laser emitter and the workpiece to be welded, and includes a heat conductive block. The bottom of the heat conductive block is in contact with the workpiece to be welded. The heat conductive block is provided with a laser through hole for the laser of the laser emitter to pass through. The thermal conductivity of the heat conductive block is higher than the thermal conductivity of the workpiece to be welded.

[0007] Optionally, the heat conductive block has a cavity filled with a cooling medium, and the heat conductive block further includes a cooling medium inlet and a cooling medium outlet communicated with the cavity.

[0008] Optionally, the heat conductive block comprises at least two chambers, which are circumferentially arranged around the laser through hole and are not connected to each other, and each chamber comprises the cooling medium inlet and the cooling medium outlet.

[0009] Optionally, the cooling medium is a coolant, and along the extension direction of the laser through hole, in the chamber, the cooling medium inlet is arranged close to the workpiece to be welded, and the cooling medium outlet is arranged away from the workpiece to be welded; or, the cooling medium is a protective gas, and in the chamber, along the extension direction of the laser through hole, the cooling medium outlet is arranged close to the workpiece to be welded, and the cooling medium inlet is arranged away from the workpiece to be welded.

[0010] Optionally, a heat-conducting layer is provided on the bottom wall of the chamber, and the thermal conductivity of the heat-conducting layer is higher than the thermal conductivity of the heat-conducting block.

[0011] Optionally, a heat-conducting layer is further included, and an opening is provided on one side of the chamber close to the workpiece to be welded. The heat-conducting layer covers the opening and contacts the workpiece to be welded, and the thermal conductivity of the heat-conducting layer is higher than that of the heat-conducting block.

[0012] Optionally, a metal layer is connected to a side of the heat-conducting layer away from the workpiece to be welded, and the thermal conductivity of the metal layer is higher than the thermal conductivity of the heat-conducting block and lower than the thermal conductivity of the heat-conducting layer.

[0013] Optionally, the heat conductive block is further provided with a protective gas channel connected to the laser through hole.

[0014] Optionally, the central axis of the protective gas channel and the central axis of the laser through hole form an acute angle α.

[0015] Optionally, when the heat conductive block has a chamber, along the extension direction of the laser through hole, the chamber is arranged close to the workpiece to be welded, and the protective gas channel is arranged away from the workpiece to be welded; the chamber is connected to the laser through hole, the cooling medium is a protective gas, the protective gas enters from the protective gas channel, and flows out from the cooling medium inlet and the cooling medium outlet.

[0016] Optionally, the port of the laser through hole close to the workpiece to be welded is a bell mouth, and the cross-sectional area of ​​the bell mouth gradually increases along the direction close to the workpiece to be welded.

[0017] Optionally, the cross-sectional area of ​​the heat conductive block gradually increases along a direction approaching the part to be welded. Beneficial Effects

[0018] The laser welding cooling device in the present invention is arranged between the laser emitter and the workpiece to be welded, specifically, a heat conductive block is used to contact the workpiece to be welded, and the heat conductive block is provided with a laser through hole for the laser of the active laser emitter to pass through, which will not affect the normal operation of the laser emitter, and at the same time, the thermal conductivity of the heat conductive block is higher than the thermal conductivity of the workpiece to be welded, so that the heat generated when the workpiece to be welded is welded is conducted away by the heat conductive block. When the laser welding device is used to weld the busbar and the battery, the welding heat of the battery can be transferred, the performance loss of the battery can be reduced, and the heat generation explosion of the battery caused by high temperature can be prevented, thereby improving the safety during welding and the battery performance obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic longitudinal section diagram of a laser welding cooling device in Example 1 provided in a specific embodiment of the present invention;

[0020] Figure 2 It is a perspective schematic diagram of a laser welding cooling device in Example 1 provided in a specific embodiment of the present invention;

[0021] Figure 3 It is a longitudinal cross-sectional schematic diagram of the laser welding cooling device in Example 2 provided in a specific embodiment of the present invention;

[0022] Figure 4 It is a longitudinal cross-sectional schematic diagram of the laser welding cooling device in Example 3 provided in a specific embodiment of the present invention;

[0023] Figure 5 It is a schematic longitudinal section diagram of the laser welding cooling device in Example 4 provided in a specific implementation manner of the present invention.

[0024] In the figure:

[0025] 10. Laser transmitter; 20. Parts to be welded;

[0026] 100, heat conductive block; 110, laser through hole; 111, bell mouth; 120, protective gas channel; 130, chamber; 131, first interface; 132, second interface; 133, gas interface; 141, heat conductive layer; 142, metal layer. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0028] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0030] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning. Embodiment 1

[0031] Please refer to Figure 1 and Figure 2 In this embodiment, the laser welding cooling device is arranged between the laser emitter 10 and the workpiece 20 to be welded, and includes a heat conductive block 100. The bottom of the heat conductive block 100 is in contact with the workpiece 20 to be welded. The heat conductive block 100 is provided with a laser through hole 110 for the laser of the laser emitter 10 to pass through. The thermal conductivity of the heat conductive block 100 is higher than the thermal conductivity of the workpiece 20 to be welded.

[0032] The laser welding cooling device in this embodiment is arranged between the laser emitter 10 and the workpiece 20 to be welded, specifically, the heat conductive block 100 is in contact with the workpiece 20 to be welded, and the heat conductive block 100 is provided with a laser through hole 110 for the laser of the active laser emitter 10 to pass through, which will not affect the normal operation of the laser emitter 10, and at the same time, the thermal conductivity of the heat conductive block 100 is higher than the thermal conductivity of the workpiece 20 to be welded, so that the heat generated by the workpiece 20 to be welded is conducted away by the heat conductive block 100. When the laser welding device is used to weld the busbar and the battery, the welding heat of the battery can be transferred, the performance loss of the battery can be reduced, and the heat generation explosion of the battery caused by high temperature can be prevented, thereby improving the safety during welding and the battery performance obtained by production.

[0033] Furthermore, the heat conducting block 100 is also provided with a protective gas channel 120 connected to the laser through hole 110. The protective gas can be blown into the laser through hole 110 and blown toward the welding position of the welded part 20 to clean the welding slag, which is beneficial to improve the welding quality and prevent the welding slag from exploding. In addition, if a low-temperature protective gas is blown in, the effects of both welding slag cleaning and cooling can be taken into account.

[0034] In this embodiment, there are two protective gas channels 120, which are V-shaped and symmetrical about the axis of the laser through hole 110, so that the protective gas enters from the two protective gas channels 120 at the same time and merges into the laser through hole 110 together, and the purging effect is better. The number and size of the protective gas channels 120 can be selected according to actual needs, and the present invention is not limited to this.

[0035] As preferably, Figure 2 As shown, the central axis of the above-mentioned shielding gas channel 120 forms an acute angle α with the central axis of the above-mentioned laser through hole 110. Setting α to an acute angle is conducive to the shielding gas entering from the top of the heat conductive block 100 and close to the laser through hole 110, thereby avoiding large-angle corners on the path of the shielding gas and shortening the path of the shielding gas. Preferably, α is 20°-40°, specifically, α is 20°, 22°, 25°, 30°, 33°, 35°, 38°, 40°, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. Limiting α to the above range is conducive to ensuring the welding slag purging effect of the shielding gas and avoiding the gas channel 120 and the laser through hole 110 being too close to affect the mechanical strength of the heat conductive block 100.

[0036] In this embodiment, the heat conductive block 100 is made of an aluminum nitride block, which not only has a simple structure and low manufacturing cost, but also has a higher thermal conductivity and good high temperature resistance, which can improve the thermal conductivity and welding quality, while extending the service life of the heat conductive block 100.

[0037] Of course, the above-mentioned heat conductive block 100 can also be made of any one of copper, silver and gold, as long as the thermal conductivity is higher than that of the welded part 20 and it is resistant to high temperature. Technical personnel in this field can select it according to specific needs, and no specific restrictions are made here.

[0038] Optionally, the port of the laser through hole 110 close to the workpiece 20 to be welded is a bell mouth 111, and the cross-sectional area of ​​the bell mouth 111 gradually increases along the direction close to the workpiece 20 to be welded. The port of the laser through hole 110 close to the workpiece 20 to be welded is set as a bell mouth 111, and the cross-sectional area gradually increases. This cross-sectional area refers to the cross-sectional area made by a plane perpendicular to the extension direction of the central axis of the laser through hole 110, which can increase the purging area of ​​the protective gas to facilitate the purging of the welding slag of the workpiece 20 to be welded after the protective gas passes through the laser through hole 110, and the purging effect is better. Further, along the direction close to the workpiece 20 to be welded, the cross-sectional area of ​​the heat conductive block 100 gradually increases. This cross-sectional area refers to the cross-sectional area made by a plane perpendicular to the extension direction of the central axis of the laser through hole 110. The heat conductive block 100 set in this way can increase the contact area with the air and reduce the volume of the heat conductive block 100, thereby reducing the manufacturing cost of the laser welding cooling device.

[0039] The shape of the heat conductive block 100 is not limited to the above-mentioned truncated cone with gradually increasing cross-sectional area, and may also be cylindrical, hemispherical, spherical or square, and can be selected according to specific needs when used. Embodiment 2

[0040] Please refer to Figure 3 , which is different from the first embodiment, in this embodiment, the heat conductive block 100 has a chamber 130, the chamber 130 is filled with a cooling medium, and the heat conductive block 100 also includes a cooling medium inlet and a cooling medium outlet connected to the chamber 130. When the laser welding cooling device cools the workpiece 20 to be welded, the heat conductive block 100 absorbs the heat of the workpiece 20 to be welded, and the heat is circulated and discharged by the cooling medium in the chamber 130 of the heat conductive block 100, which can further improve the heat dissipation and cooling effect of the laser welding cooling device. In other embodiments, the cooling medium can also be in a non-circulating form and can be replaced regularly, which can save costs.

[0041] The shape of the chamber 130 is not limited to a truncated cone, and may also be a cylindrical, hemispherical, spherical or square shape, and may be selected according to specific needs during use.

[0042] Furthermore, the heat conductive block 100 includes at least two chambers 130 , which are circumferentially arranged around the laser through hole 110 and are not connected to each other, and each chamber 130 includes the cooling medium inlet and the cooling medium outlet. Figure 3Any one of the first interface 131 and the second interface 132 is a cooling medium inlet, and the other is a cooling medium outlet; through a plurality of chambers 130 arranged around the laser through hole 110 and not connected to each other, the plurality of chambers 130 can evenly cool and dissipate heat for the heat conductive block 100, further improving the heat dissipation effect of the laser welding cooling device, ensuring the cooling effect of the welded part 20, and improving the welding quality and the performance of the product after welding. In other embodiments, the heat conductive block 100 may include a chamber 130, which is arranged around the laser through hole 110, so that a larger capacity of cooling medium can be stored and the number of cooling medium inlets / outlets can be reduced.

[0043] Optionally, the cooling medium is a cooling liquid, and along the extension direction of the laser through hole 110, in the chamber 130, the cooling medium inlet is arranged close to the workpiece 20 to be welded, and the cooling medium outlet is arranged away from the workpiece 20 to be welded; in this embodiment, the cooling liquid is low-temperature water (liquid water below 4°C), and the cooling liquid enters the chamber 130 from bottom to top to cool the heat conductive block 100, that is, the first interface 131 is the cooling medium outlet, and the second interface 132 is the cooling medium inlet, and the cooling and heat exchange effect is better.

[0044] Alternatively, the cooling medium is a shielding gas, and in the chamber 130, along the extension direction of the laser through hole 110, the cooling medium outlet is arranged close to the workpiece 20 to be welded, and the cooling medium inlet is arranged away from the workpiece 20 to be welded. In this embodiment, the shielding gas is cold nitrogen, and the same shielding gas as that used in the shielding gas channel 120 is used to cool the workpiece 20 to be welded, which can reduce the use of gas types and reduce cooling costs; the shielding gas enters the chamber 130 from top to bottom for cooling, that is, the first interface 131 is the cooling medium inlet, and the second interface 132 is the cooling medium outlet, which has a better effect of purging welding slag and a better cooling and heat exchange effect.

[0045] The cooling medium may also be other inert gases, such as helium, neon, argon, etc., or other cooling liquids, such as aqueous solutions, organic solvents, liquid metals, etc., which are not listed here one by one.

[0046] Optionally, a heat-conducting layer 141 is provided on the bottom wall of the chamber 130, and the thermal conductivity of the heat-conducting layer 141 is higher than the thermal conductivity of the heat-conducting block 100. By providing a heat-conducting layer 141 with higher thermal conductivity, the heat absorbed by the bottom of the heat-conducting block 100 can be quickly conducted outward through the heat-conducting layer 141 and taken away by the cooling medium, thereby further improving the heat dissipation and cooling effect of the heat-conducting block 100.

[0047] Furthermore, the side of the heat-conducting layer 141 away from the workpiece 20 to be welded is connected with a metal layer 142, and the thermal conductivity of the metal layer 142 is higher than that of the heat-conducting block 100, and lower than that of the heat-conducting layer 141. When the workpiece 20 to be welded, such as a battery bus, is welded, most of the heat generated by the laser welding is conducted to the heat-conducting block 100, and then absorbed by the heat-conducting layer 141 and conducted to the metal layer 142, and the circulating cooling medium is used for cooling and heat exchange, thereby reducing the temperature of the workpiece 20 to be welded, ensuring the welding quality, and improving the safety during welding.

[0048] Specifically, the heat conducting block 100 is made of aluminum nitride, and its thermal conductivity is 310W / (mk); the heat conducting layer 141 is made of diamond, and its thermal conductivity is 2200W / (mk); the metal layer 142 is made of copper, and its thermal conductivity is 401W / (mk); the thickness of the heat conducting layer 141 and the metal layer 142 are both 3 times or more of the thickness of the to-be-welded part 20 (such as a busbar, the thermal conductivity of the busbar is generally 205W / (mk)), and 6 times in this embodiment; the thickness of the heat conducting block 100 is 6 times the thickness of the to-be-welded part 20. Limiting the thickness of the heat conducting layer 141 and the metal layer 142 within the above range is conducive to reducing costs while ensuring the heat dissipation effect.

[0049] Furthermore, the thickness of the heat conductive block 100 between the metal layer 142 and the component to be welded 20 is 1 / 2 of the thickness of the component to be welded 20 .

[0050] Optionally, the heat conducting layer 141 is made of any one of diamond, heat conducting graphite and cubic boron arsenide; the metal layer 142 is made of any one of aluminum, copper, silver and gold. Those skilled in the art can select according to specific needs, which will not be described here. Embodiment 3

[0051] The difference from the above-mentioned embodiment 2 is that, Figure 4 As shown, the chamber 130 in this embodiment is provided with an opening on one side close to the workpiece 20 to be welded, and the heat-conducting layer 141 covers the opening and directly contacts the workpiece 20 to be welded, and the heat-conducting layer 141 has a higher heat-conducting coefficient than the heat-conducting block 100. By directly contacting the heat-conducting layer 141 with higher heat-conducting capacity with the workpiece 20 to be welded, the workpiece 20 to be welded can be better cooled.

[0052] In this embodiment, the heat conducting layer 141 is a diamond layer, which has a better heat conducting effect. Embodiment 4

[0053] The difference from the above-mentioned embodiment 2 is that, Figure 5As shown, in this embodiment, when the heat conductive block 100 has a chamber 130, along the extension direction of the laser through hole 110, the chamber 130 is arranged close to the workpiece 20 to be welded, and the protective gas channel 120 is arranged away from the workpiece 20 to be welded; the chamber 130 is connected to the laser through hole 110, and the cooling medium is a protective gas, which enters from the protective gas channel 120 and flows out from the cooling medium inlet, the cooling medium outlet and the end of the laser through hole 110. In this embodiment, the cooling medium inlet and the cooling medium outlet are combined into the same gas interface 133. That is, the above-mentioned protective gas is a low-temperature inert gas, such as nitrogen, helium, etc., and not only the protective gas is blown into the protective gas channel 120 to blow off the welding slag and cool the welding workpiece 20, but the protective gas blown into the chamber 130 is also used to cool the heat conductive block 100. Then the protective gas is discharged from the gas interface 133, and the functions of cooling and blowing off the welding slag are realized at the same time. The ability to blow off the welding slag is stronger, and the amount of medium used is less, which can further reduce the cooling cost of the welding workpiece 20 to be welded.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. 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 claims of the present invention.

Claims

1. Laser welding cooling device, characterized in that, The heat conductive block (100) is arranged between a laser emitter (10) and a workpiece to be welded (20), wherein the bottom of the heat conductive block (100) contacts the workpiece to be welded (20), the heat conductive block (100) is provided with a laser through hole (110) for the laser of the laser emitter (10) to pass through, and the heat conductive block (100) has a higher heat conductivity than the workpiece to be welded (20); the heat conductive block (100) has a chamber (130), the chamber (130) is filled with a cooling medium, and the heat conductive block (100) further comprises a cooling medium communicating with the chamber (130). The invention relates to a heat-conducting layer (141), wherein the chamber (130) is provided with an opening on a side close to the workpiece (20) to be welded, the heat-conducting layer (141) covers the opening and is in contact with the workpiece (20) to be welded, and the heat conductivity of the heat-conducting layer (141) is higher than the heat conductivity of the heat-conducting block (100); and the heat-conducting layer (141) is connected to a metal layer (142) on a side away from the workpiece (20) to be welded, and the heat conductivity of the metal layer (142) is higher than the heat conductivity of the heat-conducting block (100) and lower than the heat conductivity of the heat-conducting layer (141).

2. The laser welding cooling device according to claim 1, characterized in that: The heat conducting block (100) comprises at least two chambers (130), the at least two chambers (130) are arranged circumferentially around the laser through hole (110) and are not interconnected, and each chamber (130) comprises the cooling medium inlet and the cooling medium outlet.

3. The laser welding cooling device according to claim 1, characterized in that: The cooling medium is a cooling liquid, and along the extension direction of the laser through hole (110), in the chamber (130), the cooling medium inlet is arranged close to the workpiece to be welded (20), and the cooling medium outlet is arranged away from the workpiece to be welded (20); or, The cooling medium is a protective gas, and in the chamber (130), along the extension direction of the laser through hole (110), the cooling medium outlet is arranged close to the workpiece to be welded (20), and the cooling medium inlet is arranged away from the workpiece to be welded (20).

4. The laser welding cooling device according to any one of claims 1 to 3, characterized in that: The heat conducting block (100) is further provided with a protective gas channel (120) connected to the laser through hole (110).

5. The laser welding cooling device according to claim 4, characterized in that: The central axis of the protective gas channel (120) and the central axis of the laser through hole (110) form an acute angle α.

6. The laser welding cooling device according to claim 5, characterized in that: When the heat conductive block (100) has a chamber (130), along the extension direction of the laser through hole (110), the chamber (130) is arranged close to the workpiece to be welded (20), and the protective gas channel (120) is arranged away from the workpiece to be welded (20); the chamber (130) is connected to the laser through hole (110), the cooling medium is a protective gas, the protective gas enters from the protective gas channel (120), and flows out from the cooling medium inlet and the cooling medium outlet.

7. The laser welding cooling device according to any one of claims 1 to 3, characterized in that: The end of the laser through hole (110) close to the workpiece to be welded (20) is a bell mouth (111), and the cross-sectional area of ​​the bell mouth (111) gradually increases in a direction close to the workpiece to be welded (20).

8. The laser welding cooling device according to any one of claims 1 to 3, characterized in that: Along the direction approaching the part to be welded (20), the cross-sectional area of ​​the heat conducting block (100) gradually increases.

Images