CN110303246B

CN110303246B - Seal welding method and bipolar plate

Info

Publication number: CN110303246B
Application number: CN201910690644.0A
Authority: CN
Inventors: 王建刚; 胡学安; 胡张薇; 胡俊; 李辉
Original assignee: Wuhan Huagong Laser Engineering Co Ltd
Current assignee: Wuhan Huagong Laser Engineering Co Ltd
Priority date: 2019-07-29
Filing date: 2019-07-29
Publication date: 2021-10-29
Anticipated expiration: 2039-07-29
Also published as: CN110303246A

Abstract

The embodiment of the application provides a sealing welding method and a bipolar plate, and relates to the technical field of battery module processing. The method comprises the following steps of adjusting the relative position between a galvanometer type laser welding device and a polar plate to be welded and adjusting the laser path of the galvanometer type laser welding device, so that a laser beam emitted by the galvanometer type laser welding device can be focused on the polar plate to be welded; and welding the polar plate to be welded according to a concentric circle type laser scanning mode by the vibrating mirror type laser welding equipment. The welding efficiency can be improved, and the air tightness of the welded bipolar plate in the using process is improved.

Description

Seal welding method and bipolar plate

Technical Field

The application relates to the technical field of battery module processing, in particular to a sealing welding method and a bipolar plate.

Background

Fuel cells are an emerging power generation technology following the primary power generation technology, and the operating principle of fuel cells is to convert chemical energy into electric energy, and the final product is water, so that fuel cells are also a pollution-free, high-efficiency, noiseless, continuously-operable power device, and are called as ultimate clean fuel.

However, for the metal bipolar plate adopted in the existing fuel cell, the anode and the cathode are generally made of metal sheets, and then the anode and the cathode are connected based on a sectional welding mode to form a flow channel therebetween.

Disclosure of Invention

Objects of the present application include, for example, providing a seal welding method and a bipolar plate that can improve welding efficiency and improve gas tightness of the welded bipolar plate during use.

The embodiment of the application can be realized as follows:

in a first aspect, an embodiment of the present application provides a seal welding method, including:

adjusting the relative position between a galvanometer type laser welding device and a polar plate to be welded and adjusting a laser light path of the galvanometer type laser welding device, so that a laser beam emitted by the galvanometer type laser welding device can be focused on the polar plate to be welded;

and welding the polar plate to be welded according to a concentric circle type laser scanning mode by the vibrating mirror type laser welding equipment.

In an alternative embodiment, the number of concentric circles in the concentric circle type laser scanning mode is multiple, and adjacent concentric circles are partially overlapped.

In an alternative embodiment, the overlap ratio between adjacent concentric circles is 50% to 90%.

In an alternative embodiment, the welding track of the galvanometer laser welding device when welding the plates to be welded includes at least one of a straight line, a curved line and a broken line.

In an optional embodiment, the width of a weld seam formed by welding the polar plates to be welded by the galvanometer type laser welding equipment in a concentric circle type laser scanning mode is 0.1mm-0.8 mm.

In an optional embodiment, the galvanometer laser welding apparatus includes a control device, a laser, a collimator, a total reflection block, a CCD module, a galvanometer, and a focusing mirror, and the step of adjusting a laser path of the galvanometer laser welding apparatus includes:

the positions of the laser and the CCD module relative to the total reflection block are adjusted through the control device, so that reflected light can enter the CCD module after being transmitted by the focusing mirror, reflected by the vibrating mirror and transmitted by the total reflection block, and the polar plate to be welded is monitored or positioned; and

and the laser beam emitted by the laser enters the total reflection block after being shaped by the collimating mirror, enters the vibrating mirror after being reflected by the total reflection block, and enters the focusing mirror after being deflected by the vibrating mirror and is focused to the polar plate to be welded by the focusing mirror.

In an optional embodiment, the galvanometer laser welding device includes a control device, a laser, a collimator, a total reflection block, a CCD module, a galvanometer, and a focusing mirror, and the step of adjusting a laser path of the galvanometer laser welding device includes:

the positions of the laser and the CCD module relative to the total reflection block are adjusted through the control device, so that reflected light can enter the CCD module after being transmitted by the focusing mirror and reflected by the vibrating mirror and the total reflection block for two times, and the monitoring or positioning of a polar plate to be welded is realized; and

and the laser beam emitted by the laser enters the total reflection block after being shaped by the collimating mirror, enters the vibrating mirror after being transmitted by the total reflection block, is deflected by the vibrating mirror and enters the focusing mirror, and is focused to the polar plate to be welded by the focusing mirror.

In an optional embodiment, the electrode plate to be welded is placed on a welding platform provided with a movement module, the movement module is connected with the control device, and the sealing welding method further includes:

the control device controls the movement of the movement module and drives the to-be-welded polar plate on the welding platform to move so as to cooperate with the galvanometer type laser welding equipment to weld different positions on the to-be-welded polar plate.

In a second aspect, the present embodiments provide a bipolar plate applied to a fuel cell, wherein the bipolar plate is welded based on the seal welding method according to any one of the above embodiments.

In an alternative embodiment, the bipolar plate has a weld thereon having a width of 0.1mm to 0.8 mm.

The beneficial effects of the embodiment of the application include, for example:

in the sealing welding method and the bipolar plate, the polar plate to be welded is welded by the galvanometer type laser welding equipment in a concentric circle type scanning mode, the welding area of the polar plate to be welded is not required to be segmented, on one hand, the welding efficiency of the bipolar plate, especially the bipolar plate with a large width, can be greatly improved, and on the other hand, the air tightness of the welded bipolar plate in the using process can be effectively improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic block structure diagram of a galvanometer laser welding apparatus provided in an embodiment of the present application;

FIG. 2 is a schematic flow chart of a seal welding method according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of concentric circles in a concentric circle type scanning manner according to an embodiment of the present application;

FIG. 4 is a schematic diagram of overlapping of adjacent concentric circles in a concentric circle type scanning manner according to an embodiment of the present application;

FIG. 5 is another schematic diagram of overlapping multiple adjacent concentric circles in a concentric circle scanning manner according to an embodiment of the present application;

FIG. 6 is a schematic diagram of optical paths when laser beams exist and reflected light exists among a CCD module, a total reflection block and a laser in the galvanometer type laser welding device;

FIG. 7 is another schematic diagram of the optical paths of the CCD module, the total reflection block, the laser beam existing between the lasers and the reflected light in the galvanometer laser welding device;

fig. 8 is a schematic diagram of a welding path according to an embodiment of the present application.

Icon: 10-galvanometer laser welding equipment; 11-a laser; 12-a collimating mirror; 13-total reflection block; 14-a galvanometer; 15-a focusing mirror; 16-a CCD module; 17-a control device; 18-welding platform.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. are used for indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship which the present invention product is usually put into use, it is only for convenience of describing the present application and simplifying the description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation and be operated, and thus, should not be construed as limiting the present application.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present application may be combined with each other without conflict.

Referring to fig. 1, a schematic diagram of a galvanometer laser welding apparatus 10 according to the present embodiment is shown, where the galvanometer laser welding apparatus 10 is used for laser welding a plate to be welded. Alternatively, the galvanometer laser welding apparatus 10 may include, but is not limited to, a laser 11, a collimating mirror 12, a total reflection block 13, a galvanometer 14, a focusing mirror 15, a CCD (Charge Coupled Device) module 16, and a control Device 17 shown in fig. 1.

In this embodiment, the laser 11 may be, but is not limited to, a fiber laser 11 with a good beam quality, for example, the laser beam quality M emitted by the fiber laser 11²<1.8。

The hologram 13 is a laser optical device for transmitting visible light, reflecting laser light (or reflecting visible light, transmitting laser light), and the like, so that the light beam transmitted and reflected by the hologram 13 can be coaxially incident on other devices (such as the galvanometer 14 and the like).

The galvanometer 14 is used to deflect an incident light beam (e.g., a parallel light beam) to a predetermined position, and the galvanometer 14 may be driven by, but not limited to, two servo motors to deflect the mirror to achieve the deflection of the incident light beam.

The CCD module 16 is used to monitor the welding area on the plate to be welded in real time or to position the plate to be welded.

The control device 17 is used for realizing the setting of welding parameters, scanning modes and motion axis parameters, and controlling the laser 11, the CCD module 16, the galvanometer 14, the welding platform 18 and the like to realize the welding of the polar plate to be welded according to the set welding parameters, scanning modes, motion parameters and the like.

In practical implementation, the laser 11 emits a laser beam under the control of the control device 17, the laser beam generated by the laser 11 is transmitted to the collimating mirror 12 through a transmission medium such as an optical fiber, so that the divergent laser beam is integrated into a parallel beam by the collimating mirror 12, the parallel beam is reflected or transmitted to the oscillating mirror 14 through the total reflection block 13, deflected to a preset position by the oscillating mirror 14, and focused on the surface of the plate to be welded through the focusing mirror 15, so as to perform laser welding on the plate to be welded.

Meanwhile, the reflected light transmitted by the focusing mirror 15, reflected by the galvanometer 14, and transmitted or reflected by the total reflection block 13 can enter the CCD module 16 to monitor the welding area on the plate to be welded in real time or to position the plate to be welded. The reflected light may be natural light formed when the laser beam interacts with the electrode plate to be welded in the welding process, or when the brightness of the natural light cannot meet the welding monitoring or positioning requirement, the reflected light may also be formed by the natural light and an external light source, which is not limited herein.

Optionally, for the large-width polar plate to be welded, when the focusing mirror 15 cannot complete welding at one time, in order to realize welding of different positions of the polar plate to be welded and improve welding efficiency, in this embodiment, a mode that the movement module is matched with the focusing mirror 15 may be adopted to realize welding of the large-width polar plate to be welded.

For example, a motion module (e.g., a two-dimensional motion module or a three-dimensional motion module) may be disposed on the welding platform 18 for fixing the electrode plates to be welded, and the motion module is controlled by the control device 17 to move so as to drive the electrode plates to be welded fixed on the welding platform 18 to move (e.g., move on the horizontal plane X, Y axis), and complete welding by cooperating with the focusing mirror 15, so as to meet the welding requirement for large-sized electrode plates to be welded. As an implementation, the motion module can be generally implemented by, but not limited to, a combination of a motor and a screw.

In addition, the material of the electrode plate to be welded may be, but is not limited to, a metal material, such as stainless steel.

Further, based on the description of the galvanometer laser welding apparatus 10, please refer to fig. 2, which is a schematic flowchart of a sealing welding method provided in the embodiment of the present application, and the sealing welding method is implemented based on the galvanometer laser welding apparatus 10, and the sealing welding method provided in the embodiment of the present application is described in detail below with reference to fig. 2. It should be noted that the sealing welding method given in the embodiment of the present application is not limited by fig. 2 and the following specific sequence. It should be understood that the order of some steps in the sealing welding method provided in the present application may be interchanged according to actual needs, or some steps may be omitted or deleted.

Step S11, adjusting the relative position between the galvanometer laser welding apparatus 10 and the electrode plate to be welded, and adjusting the laser path of the galvanometer laser welding apparatus 10, so that the laser beam emitted by the galvanometer laser welding apparatus 10 can be focused on the electrode plate to be welded.

Two polar plates in the polar plates to be welded can be overlapped and horizontally fixed on the profiling jig in an up-and-down alignment mode, the two polar plates are simultaneously pressed to ensure that the surfaces of the polar plates are smooth, and then the profiling jig with the polar plates to be welded are fixed on the welding platform 18.

After the polar plate to be welded is placed, the galvanometer laser welding equipment 10 and the polar plate to be welded are adjusted, so that a laser beam emitted by a laser 11 in the galvanometer laser welding equipment 10 can be focused on the surface of the polar plate to be welded, reflected light transmitted by the focusing mirror 15 and reflected by the galvanometer 14 can be incident to the CCD module 16, wherein the laser beam is used for welding the polar plate to be welded, and the reflected light is used for positioning the polar plate to be welded and the welding position on the polar plate to be welded.

And step S12, welding the electrode plates to be welded by the galvanometer laser welding device 10 according to a concentric laser scanning manner.

As shown in fig. 3 and 4, one or more concentric circles may be used in the concentric circle type laser scanning system. Alternatively, concentric circles of different diameters, numbers and spacings may be used, depending on the welding requirements. In practical implementation, the width of the welding seam can be accurately controlled based on the concentric circle type laser scanning mode, for example, the width of the welding seam formed by welding can be 0.1-0.8mm, and the welding quality is ensured.

Note that, when there are a plurality of concentric circles in the concentric circle type laser scanning system, the different concentric circles may have the same size as shown in fig. 4 or different sizes as shown in fig. 5. In addition, the distances between adjacent rings in the same concentric circle may be the same as or different from that shown in fig. 4, and this embodiment is not limited herein.

In addition, according to the requirement of sealing (air tightness), the adjacent concentric circles may have a partial overlap as shown in fig. 4, for example, the overlap ratio between the adjacent concentric circles is 50% -90%. In practical implementation, the higher the sealing requirement, the higher the overlapping ratio between adjacent concentric circles. Note that the hatched portion shown in fig. 4 is an overlapping portion between adjacent two concentric circles.

Compared with the prior art that the welding of the bipolar plates is caused by adopting a segmented welding mode, the welding method has the problems of more welding cross points, low welding efficiency and easy welding penetration, and the existing sealing welding method is not suitable for welding ultrathin materials or materials with thick upper parts and thin lower parts. In contrast, the sealing welding method implemented based on the concentric laser scanning mode provided by the embodiment of the application does not need to segment the welding area when welding large-width bipolar plates and the like, reduces the welding intersection points, can improve the welding efficiency, and can effectively ensure the quality of the welded bipolar plates, for example, the welding seam size can be accurately controlled, higher welding strength can be obtained, and good air tightness and appearance can be ensured, especially for welding the bipolar plates in fuel cells with the size of less than 0.2 mm.

In addition, in the sealing welding method provided in this embodiment, the focusing lens 15 does not need a field lens with a long focal length, and can also focus the laser beam onto the surface of the to-be-welded pole plate, so as to weld the to-be-welded pole plate, thereby improving the adaptability of the sealing welding method.

Further, the implementation manner of adjusting the laser path of the galvanometer laser welding apparatus 10 in step S11 may be various according to different actual requirements.

For example, referring to fig. 6, the positions of the laser 11 and the CCD module 16 relative to the total reflection block 13 are adjusted by the control device 17, so that the incident reflected light can enter the CCD module 16 after being transmitted by the focusing mirror 15, reflected by the vibrating mirror 14 and transmitted by the total reflection block 13, so as to position or monitor the electrode plate to be welded; and the laser beam emitted by the laser 11 enters the total reflection block 13 after being collimated by the collimating mirror 12, enters the vibrating mirror 14 after being reflected by the total reflection block 13, and enters the focusing mirror 15 after being deflected by the vibrating mirror 14 and is focused to the polar plate to be welded by the focusing mirror 15 so as to weld the polar plate to be welded.

For another example, referring to fig. 7, the control device 17 adjusts the positions of the laser 11 and the CCD module 16 relative to the total reflection block 13, so that the incident reflected light can enter the CCD module 16 after being reflected twice by the focusing mirror 15, the vibrating mirror 14 and the total reflection block 13, so as to position or monitor the electrode plate to be welded; and the laser beam emitted by the laser 11 enters the total reflection block 13 after being shaped by the collimating mirror 12, enters the vibrating mirror 14 after being transmitted by the total reflection block 13, and enters the focusing mirror 15 after being deflected by the vibrating mirror 14 and is focused on the to-be-welded polar plate by the focusing mirror 15 so as to weld the to-be-welded polar plate.

In the above two embodiments for adjusting the optical path, the incident angle between the reflected light and the laser beam when the laser beam is incident on the total reflection block 13 may be, but is not limited to, 45 degrees, that is, the mirror in the total reflection block 13 may be, but is not limited to, a 45-degree mirror.

It should be noted that, as shown in fig. 8, the welding track of the galvanometer laser welding apparatus 10 when welding the plates to be welded may include, but is not limited to, at least one of a straight line, a curved line and a broken line, and the embodiment is not limited herein.

In addition, with the sealing welding method, protective gas can be added during actual welding to reduce the oxidation degree of liquid metal during welding and reduce welding defects caused by oxidation of metal, such as thermal deformation and the like. The protective gas may be, but is not limited to, any one of helium, argon, carbon dioxide, nitrogen, hydrogen, and the like.

Further, as an embodiment, for the plates to be welded with different widths, the plates to be welded may be placed on different welding platforms 18 for welding, for example, for a large-width plate to be welded, the plates to be welded may be placed on a welding platform 18 provided with a movement module, the movement module is connected to the control device 17, and the seal welding method may further include: the control device 17 controls the motion module to move and drives the to-be-welded pole plate on the welding platform 18 to move so as to cooperate with the galvanometer type laser welding equipment 10 to weld different positions on the to-be-welded pole plate.

Based on the above description of the sealing welding method, the welding process of the fuel cell bipolar plate (stainless steel) with a thickness of 0.1mm is described below by taking the stitch welding as an example, and the following contents are provided. The welding requirement is that the bipolar plate is made of stainless steel, the welding area is a rectangle with the size of 300 x 380mm, the welding strength per millimeter is required to be larger than 40N (newton), the width of a welding line is smaller than 0.4mm, no air leakage is guaranteed for 10 minutes under the air pressure of 0.2Mpa, the welding efficiency is larger than 1 minute per sheet, and the appearance of the surface of the welding line is guaranteed to be attractive and free of splashing.

(1) And vertically aligning and stacking two polar plates to be welded on the profiling jig, pressing the polar plates to ensure that the surfaces are smooth, and fixing the profiling jig provided with the polar plates to be welded on the welding platform 18.

(2) The galvanometer laser welding apparatus 10 is adjusted according to the schematic optical path diagram of the galvanometer laser welding apparatus 10 shown in fig. 1 and 6 so that the laser beam can be focused on the surface of the plate to be welded and the reflected light can enter the CCD module 16. Wherein, a field lens of F160 can be adopted, the scanning mode is concentric circles shown in fig. 3, the sizes of all circles in the concentric circles are 0.1, 0.2 and 0.3mm respectively, the welding power is set to 85W, the welding speed is set to 1500mm/s, the speed of the motion axis is set to 80mm/s, welding is carried out according to a preset welding path (such as a straight line), and nitrogen can be blown in as protective gas in the welding process.

The welding effect is as follows: the welding strength of each millimeter can reach 45N, the width of a welding seam is only 0.35mm, no air leakage can be ensured for 10 minutes under the air pressure of 0.2Mpa, the welding efficiency is about 55 seconds per sheet, the surface of the welding seam is attractive and has no splash, and the welding requirement is met.

Further, the embodiment of the present application also provides a bipolar plate, which can be welded based on the above-mentioned seal welding method. Optionally, the bipolar plate has a weld thereon having a width of 0.1mm to 0.8 mm. In addition, the bipolar plate may be, but is not limited to, a plate made of a metal material applied to a fuel cell.

It should be noted that, since the bipolar plate is welded by the above-mentioned sealing welding method, that is, the bipolar plate has the same or corresponding technical features as the above-mentioned sealing welding method, reference may be made to the detailed description of the above-mentioned sealing welding method for the detailed description of the bipolar plate, and the present embodiment is not limited thereto.

In summary, in the seal welding method and the bipolar plate provided by the present application, the galvanometer laser welding device 10 employs a concentric scanning manner to weld the polar plate to be welded, and the welding area of the polar plate to be welded does not need to be segmented, so that on one hand, the welding efficiency of the bipolar plate can be greatly improved, the thermal deformation can be reduced, especially the bipolar plate with a large width, and on the other hand, the air tightness of the welded bipolar plate in the using process can be effectively improved.

In addition, the sealing welding realized based on the concentric circle type scanning mode can also accurately control the size of a welding line, obtain higher welding strength, ensure good air tightness and appearance, and is particularly suitable for welding the bipolar plate in the fuel cell below 0.2 mm.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A seal welding method, comprising:

welding the polar plate to be welded by the galvanometer type laser welding equipment according to a concentric circle type laser scanning mode without segmenting a welding area;

the laser scanning device comprises a laser scanning device, a laser scanning system and a laser scanning system, wherein a plurality of concentric circles are arranged in the concentric circle type laser scanning mode, and the adjacent concentric circles are partially overlapped; the overlapping rate between every two adjacent concentric circles is 50% -90%; welding the polar plate to be welded by the galvanometer type laser welding equipment in a concentric circle type laser scanning mode to form a weld joint with the width of 0.1-0.8 mm;

the different concentric circles have different sizes, and the distances between adjacent rings in the same concentric circle are different.

2. The seal welding method according to claim 1, wherein a welding locus of the galvanometer laser welding apparatus when welding the to-be-welded polar plates includes at least one of a straight line, a curved line, and a broken line.

3. The seal welding method according to claim 1, wherein the galvanometer laser welding device comprises a control device, a laser, a collimating mirror, a total reflection block, a CCD module, a galvanometer, and a focusing mirror, and the step of adjusting the laser path of the galvanometer laser welding device comprises:

4. The seal welding method according to claim 1, wherein the galvanometer laser welding device comprises a control device, a laser, a collimating mirror, a total reflection block, a CCD module, a galvanometer, and a focusing mirror, and the step of adjusting the laser path of the galvanometer laser welding device comprises:

5. The seal welding method according to claim 3 or 4, characterized in that the pole plate to be welded is placed on a welding platform provided with a movement module, the movement module being connected with the control device, the seal welding method further comprising:

6. A bipolar plate, which is welded based on the seal welding method according to any one of claims 1 to 5, and which has a weld line having a width of 0.1mm to 0.8mm, for use in a fuel cell.