阅读说明：本技术 动力电池精密结构件激光焊接的光场分布控制方法及系统 (Light field distribution control method and system for laser welding of precise structural part of power battery ) 是由 陈勇 高峰 祝铭 池峰 李涛 杨亚涛 冯建 潘洪文 米云 伍湘红 孙弘明 于 2019-09-06 设计创作，主要内容包括：本发明提供了一种动力电池精密结构件激光焊接的光场分布控制方法及系统,所述光场分布控制方法执行以下步骤：采用激光器形成由若干个光束组合而成的多光束激光,作为在激光焊接的过程中所采用的激光；获取动力电池精密结构件在激光焊接的过程中的焊接轨迹；在激光焊接的过程中,根据焊接轨迹动态调节多光束激光中的每个光束的光场分布,进而调节多光束激光的光场分布。根据本发明的动力电池精密结构件激光焊接的光场分布控制方法,可以动态自适应的改变激光对材料的作用,以达到控制温度梯度和应力梯度的效果,进而可以避免焊接过程中出现的焊接区域材质不连续、微裂纹的问题,可以有效提高动力电池精密结构件的焊接质量。(The invention provides a light field distribution control method and a light field distribution control system for laser welding of a precise structural member of a power battery, wherein the light field distribution control method comprises the following steps: a laser is adopted to form multi-beam laser formed by combining a plurality of light beams as laser adopted in the laser welding process; acquiring a welding track of a power battery precision structural part in a laser welding process; in the laser welding process, the light field distribution of each light beam in the multi-light beam laser is dynamically adjusted according to the welding track, and then the light field distribution of the multi-light beam laser is adjusted. According to the light field distribution control method for laser welding of the precise structural member of the power battery, the effect of laser on materials can be dynamically and adaptively changed, so that the effect of controlling the temperature gradient and the stress gradient is achieved, the problems of discontinuous materials and microcracks in a welding area in the welding process can be further avoided, and the welding quality of the precise structural member of the power battery can be effectively improved.)

1. A light field distribution control method for laser welding of a precision structural member of a power battery is characterized by comprising the following steps:

Step 1: forming multi-beam laser formed by combining a plurality of light beams by using a laser, wherein the multi-beam laser is used as laser used in the laser welding process;

Step 2: acquiring a welding track of the power battery precision structural part in the laser welding process;

and step 3: and in the laser welding process, dynamically adjusting the light field distribution of each beam in the multi-beam laser according to the welding track, and further adjusting the light field distribution of the multi-beam laser.

2. The light field distribution control method according to claim 1, wherein in the step 1, the forming of the multi-beam laser in which a plurality of beams are combined includes:

the multi-beam laser is formed using a multi-beam semiconductor laser in which a plurality of laser oscillation regions are provided in a stripe shape, and a laser beam can be emitted from each of the laser oscillation regions.

3. the light field distribution control method according to claim 1, wherein in the step 2, the obtaining of the welding track of the precision structural member of the power cell during the laser welding includes:

a preset welding track of a laser welding head is obtained in a laser welding system, and the welding track comprises one or more of a curve, a plurality of straight lines or lines formed discontinuously.

4. The light field distribution control method according to claim 1, wherein in the step 3, dynamically adjusting the light field distribution of each of the multiple-beam laser light according to the welding trajectory during the laser welding, and further adjusting the light field distribution of the multiple-beam laser light includes:

Step S301: obtaining materials of a welding position of the power battery precision structural part;

Step S302: adjusting the laser beam focus position of a laser welding head of the laser;

Step S303: the laser welding head starts to work, laser is emitted to the surface of the welding position of the power battery precision structural part, laser welding is carried out, and combustion-supporting oxygen is sprayed to the welding position of the laser welding head in real time;

Step S304: dynamically adjusting the light field distribution of the central position and the peripheral position of each beam of the multi-beam laser according to the material of the welding position to realize the dynamic adjustment of the laser energy at the welding position.

5. The light field distribution control method according to claim 1, wherein in step S301, the material of the welding position of the precision structural member of the power cell comprises: copper, aluminum, titanium, stainless steel, or nickel.

6. the light field distribution control method according to claim 5, wherein in the step 3, the light field distribution of each beam of the multi-beam laser includes: quasi-normal distribution, flat-top distribution, or W-shaped distribution.

7. The light field distribution control method according to claim 1, wherein in the step 2, the step of obtaining the welding track of the precision structural member of the power cell during the laser welding comprises the following steps:

Firstly, taking a picture of the precise structural member of the power battery under a strong light environment of a laboratory by N2 pictures at a position which is vertical to the precise structural member of the power battery and is N1 meters away from the middle position of the precise structural member of the power battery, wherein N1 and N2 are preset values;

Secondly, respectively preprocessing the acquired photos, wherein the preprocessing comprises image graying and Gaussian filtering, adding pixel values of corresponding positions of the N2 groups of photos, and averaging to obtain an average image img;

Then, processing the average image by using a histogram equalization technology, and performing binarization processing on the average image processed by using the histogram equalization technology to obtain a binarized image bimg, wherein a threshold value of the binarization processing needs to be determined during the binarization processing, and the determination method of the threshold value F is as follows:

setting an initial binary threshold value formula asWhere g represents the gray scale value in the range of 0,255]Img (g) is the number of gray-scale values g according to a thresholdDetermining the foreground and the background of the image, taking the foreground as the gray value of any pixel point in the image is larger than the minimum gray value and smaller than the threshold value, and taking the background as the gray value of the pixel point is larger than the threshold value and smaller than the maximum gray value, and calculating the average gray g of the foreground_fAverage gray level g with image background_b，

Wherein, g_iis the minimum gray value, g, of all pixel points in the image_aLet F be the maximum gray value of all pixel points in the image^k＝(g_f+g_b) Average gray scale g with/2, k as foreground_fAverage gray level g with background_bThe k value is increased from 0 by 1, and g is circularly calculated_fand g_bAnd mixing g_fAnd g_bSubstitution into F^k＝(g_f+g_b) /2 to calculate F^kUp to F^k+1＝F^kThen, the threshold value determination of the binarization process is completed, and the determined threshold value F is F^k；

then, using a laplacian operator to perform trajectory detection, wherein the laplacian operator of the binarized image bimg is a second-order differential, and the formula is as follows:In the two-dimensional image function, the second order difference in the x and y directions is as follows:

So that the difference form of the Laplace operator is

and selectAs a Laplace operation template, performing convolution operation on the Laplace operator and the binary image bimg to obtain track information;

Finally, the track coordinate information Q obtained by detection is stored_xyX and y are respectively the horizontal coordinate value and the vertical coordinate value of the welding position, and the track coordinate information Q_xyThe formed track is the welding track in the laser welding process.

8. the light field distribution control method according to claim 5, wherein in the step S304, the light field distribution of the central position and the peripheral position of each beam of the multi-beam laser is dynamically adjusted according to the material of the welding position to achieve the dynamic adjustment of the laser energy at the welding position, wherein the calculation formula for adjusting the laser energy is as follows:

p(x,y,z)_ithe welding position is made of the adjusting laser energy value corresponding to the ith material, the value range of i is {1,2,3,4,5}, j is the number variable of the light beams in the multi-beam laser adopted by the laser welding of the precise structural member of the power battery, the value range is {1,2,3.. n }, and n is the total number of the light beams in the multi-beam laser adopted by the laser welding of the precise structural member of the power battery,is the amplitude of the central beam of the jth beam at the origin (x is 0, y is 0, z is 0), r_jis the wave number of the jth beam, andm is a preset refractive index in air, and m is approximately equal to 1, lambda_jIs the wavelength of the jth beam radiation in the vacuum,Is the beam waist radius of the jth laser beam, r_iHardness value of i-th material, d_iis the texture value of the i-th material, d₁、d₂、d₃、d₄、d₅Are respectively 1,2,3,4,5, f_ithe density values of the ith material are x, y and z, which are respectively an abscissa value, an ordinate value and an ordinate value.

9. The utility model provides a light field distribution control system of power battery precision construction spare laser welding which characterized in that includes:

A laser for forming a multi-beam laser composed of a plurality of light beams combined, the multi-beam laser being used as a laser used in the laser welding process;

The welding track acquisition module is used for acquiring the welding track of the power battery precision structural part in the laser welding process;

And the light field distribution adjusting module is used for dynamically adjusting the light field distribution of each light beam in the multi-light beam laser according to the welding track in the laser welding process so as to adjust the light field distribution of the multi-light beam laser.

10. The light field distribution control system according to claim 9, wherein the light field distribution adjusting module dynamically adjusts a light field distribution function formula of the light field distribution of the multi-beam laser light according to the welding trajectory as follows:

Re(x,y)_iAs a welding position of the ith materialX and y are respectively the horizontal coordinate value and the vertical coordinate value of the welding position, sign (x) is a sign function, when x is more than 0, sign (x) is 1, when x is 0, sign (x) is 0, when x is less than 0, sign (x) is-1, t is the temperature value in the welding process, u is the stress value of the welding position, and p (x, y, z)_iadjusting the laser energy value for the ith material at the welding location, the power cell precision structural member being in the same plane during welding so that the z value is a predetermined value N1 meters, p (x, y, z)_iAccording to the adjusted laser energy p (x, y, z) of different materials at different welding positions_iDetermination of the formula of calculation, Q_xyIs the welding track in the process of the laser welding.

Technical Field

The invention relates to the technical field of laser welding, in particular to a light field distribution control method and a light field distribution control system for laser welding of a power battery precision structural member.

Background

With the development of science and technology, lasers are more and more recognized by various industries. In the field of industrial processing, the application of laser technology is becoming more and more widespread, such as welding, cutting, and 3D printing. The laser welding technology has the advantages of high energy density, high welding speed, good weld formation, small heat affected zone, easy automation control and the like, and draws wide attention of researchers.

With the continuous growth of new energy automobiles, while the advantages and the share of the global new energy automobile market are gradually enlarged, the country also develops and innovates related measures in the aspect of new energy, particularly in the aspect of new energy automobiles, and the production demand of new energy power batteries is greatly increased.

Disclosure of Invention

The invention provides a light field distribution control method and a light field distribution control system for laser welding of a power battery precision structural member, which are used for realizing that both a job seeker and an enterprise team comprehensively know each other and improving the authenticity of information.

the invention provides a light field distribution control method for laser welding of a precise structural part of a power battery, which comprises the following steps:

Step 1: forming multi-beam laser formed by combining a plurality of light beams by using a laser, wherein the multi-beam laser is used as laser used in the laser welding process;

Step 2: acquiring a welding track of the power battery precision structural part in the laser welding process;

And step 3: and in the laser welding process, dynamically adjusting the light field distribution of each beam in the multi-beam laser according to the welding track, and further adjusting the light field distribution of the multi-beam laser.

Further, in the step 1, the forming a multi-beam laser composed of a combination of a plurality of beams includes:

The multi-beam laser is formed using a multi-beam semiconductor laser in which a plurality of laser oscillation regions are provided in a stripe shape, and a laser beam can be emitted from each of the laser oscillation regions.

Further, in the step 2, the obtaining a welding track of the precision structural component of the power battery during the laser welding includes:

a preset welding track of a laser welding head is obtained in a laser welding system, and the welding track comprises one or more of a curve, a plurality of straight lines or lines formed discontinuously.

Further, in the step 3, the dynamically adjusting the light field distribution of each beam of the multi-beam laser according to the welding trajectory during the laser welding, and further adjusting the light field distribution of the multi-beam laser includes:

Step S301: obtaining materials of a welding position of the power battery precision structural part;

Step S302: adjusting the laser beam focus position of a laser welding head of the laser;

Step S303: the laser welding head starts to work, laser is emitted to the surface of the welding position of the power battery precision structural part, laser welding is carried out, and combustion-supporting oxygen is sprayed to the welding position of the laser welding head in real time;

Step S304: dynamically adjusting the light field distribution of the central position and the peripheral position of each beam of the multi-beam laser according to the material of the welding position to realize the dynamic adjustment of the laser energy at the welding position.

Further, in step S301, the materials of the welding position of the precision structural member of the power battery include: copper, aluminum, titanium, stainless steel, or nickel.

Further, in the step 3, the light field distribution of each beam of the multi-beam laser includes: quasi-normal distribution, flat-top distribution, or W-shaped distribution.

further, in the step 2, the step of obtaining the welding track of the precision structural component of the power battery during the laser welding includes the following steps:

Firstly, taking a picture of the precise structural member of the power battery under a strong light environment of a laboratory by N2 pictures at a position which is vertical to the precise structural member of the power battery and is N1 meters away from the middle position of the precise structural member of the power battery, wherein N1 and N2 are preset values;

Secondly, respectively preprocessing the acquired photos, wherein the preprocessing comprises image graying and Gaussian filtering, adding pixel values of corresponding positions of the N2 groups of photos, and averaging to obtain an average image img;

Then, processing the average image by using a histogram equalization technology, and performing binarization processing on the average image processed by using the histogram equalization technology to obtain a binarized image bimg, wherein a threshold value of the binarization processing needs to be determined during the binarization processing, and the determination method of the threshold value F is as follows:

Setting an initial binary threshold value formula asWhere g represents the gray scale value in the range of 0,255]Img (g) is the number of gray values g, the foreground and the background of the image are determined according to the threshold, the gray value of any pixel point in the image is larger than the minimum gray value and smaller than the threshold to be the foreground, otherwise, the gray value of the pixel point is larger than the threshold and smaller than the maximum gray value to be the background, and the average gray g of the foreground is calculated_faverage gray level g with image background_b，

wherein gi is the minimum gray value among all pixel points in the image, g_alet F be the maximum gray value of all pixel points in the image^k＝(g_f+g_b) Average gray scale g with/2, k as foreground_fAverage gray level g with background_bThe k value is increased from 0 by 1, and g is circularly calculated_fand g_bAnd mixing g_fand g_bsubstitution into F^k＝(g_f+g_b) /2 to calculate F^kup to F^k+1＝F^kThen, the threshold value determination of the binarization process is completed, and the determined threshold value F is F^k；

then, using Laplace operator to perform track detection and binarize the graphthe laplacian like bimg is a second order differential, and the formula is:In the two-dimensional image function, the second order difference in the x and y directions is as follows:

So that the difference form of the Laplace operator is

▽²bimg ═ bimg (x +1, y) + bimg (x-1, y) + bimg (x, y +1) + bimg (x, y-1) -4bimg (x, y), and selectedAs a Laplace operation template, performing convolution operation on the Laplace operator and the binary image bimg to obtain track information;

Finally, the track coordinate information Q obtained by detection is stored_xyX and y are respectively the horizontal coordinate value and the vertical coordinate value of the welding position, and the track coordinate information Q_xyThe formed track is the welding track in the laser welding process.

Further, in the step S304, the light field distribution of the central position and the peripheral position of each beam of the multi-beam laser is dynamically adjusted according to the material of the welding position to realize the dynamic adjustment of the laser energy at the welding position, wherein the calculation formula for adjusting the laser energy is as follows:

p(x,y,z)_iThe welding position is made of the adjusted laser energy value corresponding to the ith material, the value range of i is {1,2,3,4,5}, and j is the laser welding collection of the power battery precision structural partThe numerical variable of the light beams in the multi-beam laser is in a value range of {1,2,3.. n }, wherein n is the total number of the light beams in the multi-beam laser adopted by the laser welding of the precise structural member of the power battery,is the amplitude of the central beam of the jth beam at the origin (x is 0, y is 0, z is 0), rj is the wave number of the jth beam, andm is a preset refractive index in air, and m is approximately equal to 1, lambda_jis the wavelength of the jth beam radiation in the vacuum,Is the beam waist radius of the jth laser beam, r_iHardness value of i-th material, d_iIs the texture value of the i-th material, d₁、d₂、d₃、d₄、d₅Are respectively 1,2,3,4,5, f_ithe density values of the ith material are x, y and z, which are respectively an abscissa value, an ordinate value and an ordinate value.

The light field distribution control method for laser welding of the precise structural part of the power battery, provided by the embodiment of the invention, has the following beneficial effects: the light field distribution of each light beam in the multi-beam laser is dynamically adjusted according to the welding track, and then the light field distribution of the multi-beam laser is adjusted, so that the effect of the laser on the material can be dynamically and adaptively changed, the effect of controlling the temperature gradient and the stress gradient can be achieved, the problems of discontinuous materials and microcracks of a welding area in the welding process can be further avoided, and the welding quality of the precise structural member of the power battery can be effectively improved.

The invention also provides a light field distribution control system for laser welding of the precise structural member of the power battery, which comprises the following components:

a laser for forming a multi-beam laser composed of a plurality of light beams combined, the multi-beam laser being used as a laser used in the laser welding process;

the welding track acquisition module is used for acquiring the welding track of the power battery precision structural part in the laser welding process;

and the light field distribution adjusting module is used for dynamically adjusting the light field distribution of each light beam in the multi-light beam laser according to the welding track in the laser welding process so as to adjust the light field distribution of the multi-light beam laser.

Further, the light field distribution adjusting module dynamically adjusts a light field distribution function formula of the light field distribution of the multi-beam laser according to the welding track as follows:

Re(x,y)_iThe light field distribution of the multi-beam laser at the welding position of the ith material is adjusted, x and y are respectively an abscissa value and an ordinate value of the welding position, sign (x) is a sign function, when x is more than 0, sign (x) is 1, when x is 0, sign (x) is 0, when x is less than 0, sign (x) is-1, t is a temperature value in the welding process, u is a stress value of the welding position, and p (x, y, z)_iadjusting the laser energy value for the ith material at the welding location, the power cell precision structural member being in the same plane during welding so that the z value is a predetermined value N1 meters, p (x, y, z)_iAccording to the adjusted laser energy p (x, y, z) of different materials at different welding positions_iDetermination of the formula of calculation, Q_xyis the welding track in the process of the laser welding.

The light field distribution control system for laser welding of the precise structural part of the power battery provided by the embodiment of the invention has the following beneficial effects: the light field distribution adjusting module dynamically adjusts the light field distribution of each light beam in the multi-beam laser according to the welding track, and then adjusts the light field distribution of the multi-beam laser, so that the effect of the laser on the material can be dynamically and adaptively changed, the effect of controlling the temperature gradient and the stress gradient can be achieved, the problems of discontinuous materials and microcracks of a welding area in the welding process can be further avoided, and the welding quality of the precise structural member of the power battery can be effectively improved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic flow chart of a light field distribution control method for laser welding of a precision structural member of a power battery according to an embodiment of the present invention;

fig. 2 is a block diagram of a light field distribution control system for laser welding of a precision structural member of a power battery in an embodiment of the invention.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

the embodiment of the invention provides a light field distribution control method for laser welding of a precise structural member of a power battery, which comprises the following steps of:

Step 1: forming multi-beam laser formed by combining a plurality of light beams by using a laser, wherein the multi-beam laser is used as laser used in the laser welding process;

Step 2: acquiring a welding track of the power battery precision structural part in the laser welding process;

and step 3: and in the laser welding process, dynamically adjusting the light field distribution of each beam in the multi-beam laser according to the welding track, and further adjusting the light field distribution of the multi-beam laser.

The working principle of the technical scheme is as follows: and forming multi-beam laser formed by combining a plurality of light beams, and dynamically adjusting the light field distribution of each light beam in the multi-beam laser according to the welding track in the laser welding process so as to adjust the light field distribution of the multi-beam laser.

The beneficial effects of the above technical scheme are: the light field distribution of each light beam in the multi-beam laser is dynamically adjusted according to the welding track, and then the light field distribution of the multi-beam laser is adjusted, so that the effect of the laser on the material can be dynamically and adaptively changed, the effect of controlling the temperature gradient and the stress gradient can be achieved, the problems of discontinuous materials and microcracks of a welding area in the welding process can be further avoided, and the welding quality of the precise structural member of the power battery can be effectively improved.

In one embodiment, in the step 1, the forming a multi-beam laser composed of a combination of several beams includes:

the multi-beam laser is formed using a multi-beam semiconductor laser in which a plurality of laser oscillation regions are provided in a stripe shape, and a laser beam can be emitted from each of the laser oscillation regions.

The working principle of the technical scheme is as follows: the multi-beam semiconductor laser is made of gallium nitride (GaN) group III-V compound semiconductor, and the light output levels of the respective beams in the multi-beam laser are equal to each other while being easily positioned.

it should be noted that other lasers, such as gas laser, fiber laser, dye laser, etc., may be used to form a multi-beam laser that is a combination of several beams.

the beneficial effects of the above technical scheme are: with the multi-beam semiconductor laser, multi-beam laser light is formed.

In one embodiment, in the step 2, the obtaining a welding track of the precision structural component of the power battery during the laser welding includes:

A preset welding track of a laser welding head is obtained in a laser welding system, and the welding track comprises one or more of a curve, a plurality of straight lines or lines formed discontinuously.

The working principle of the technical scheme is as follows: the welding locus formed by the curve includes a U shape or a V shape.

The beneficial effects of the above technical scheme are: the preset welding track of the laser welding head can be obtained in the laser welding system.

in one embodiment, in the step 3, dynamically adjusting the light field distribution of each beam of the multi-beam laser according to the welding trajectory during the laser welding, and further adjusting the light field distribution of the multi-beam laser includes:

Step S301: obtaining materials of a welding position of the power battery precision structural part;

Step S302: adjusting the laser beam focus position of a laser welding head of the laser;

Step S303: the laser welding head starts to work, laser is emitted to the surface of the welding position of the power battery precision structural part, laser welding is carried out, and combustion-supporting oxygen is sprayed to the welding position of the laser welding head in real time;

step S304: dynamically adjusting the light field distribution of the central position and the peripheral position of each beam of the multi-beam laser according to the material of the welding position to realize the dynamic adjustment of the laser energy at the welding position.

The working principle of the technical scheme is as follows: in step S302, the surface of the welding position of the precision structural member of the power battery is set in the range of 0.5mm to 5mm of negative defocusing of the laser welding head, and exemplarily, is set in the range of 3mm to 4mm of negative defocusing of the laser welding head.

Further, the power of the laser welding head is 1800W-2000W, and the jet speed of the combustion-supporting oxygen is 10L/min-30L/min.

The beneficial effects of the above technical scheme are: the light field distribution of the central position and the peripheral position of each light beam in the multi-light beam laser is dynamically adjusted according to the material of the welding position so as to realize the dynamic adjustment of the laser energy at the welding position, and the action of the laser on the material can be dynamically and adaptively changed so as to achieve the effect of controlling the temperature gradient and the stress gradient; meanwhile, when the laser welding head works, combustion-supporting oxygen is sprayed to the welding position of the laser welding head in real time, so that the metal surface layer of the welding position is combusted with the oxygen, a large amount of heat is emitted, the laser welding speed is increased, and the price and the energy consumption of the laser welding head are greatly reduced.

In one embodiment, in step S301, the materials of the welding position of the precision structural member of the power battery include: copper, aluminum, titanium, stainless steel, or nickel.

the working principle of the technical scheme is as follows: in an example of welding a metal piece on a metal shell of a power battery, the metal piece is made of red copper, and the power battery shell is made of metal aluminum.

The beneficial effects of the above technical scheme are: the material for the welding position of the precision structural part of the power battery is provided.

In one embodiment, in the step 3, the light field distribution of each beam of the multi-beam laser includes: quasi-normal distribution, flat-top distribution, or W-shaped distribution.

the working principle of the technical scheme is as follows: the quasi-normal light field distribution enables the laser to form multi-focus light spots, the energy density is low, the cladding efficiency is low, and laser beams are not uniformly distributed in the transverse direction.

the energy distribution of the laser spot is more uniform due to the flat-topped light field distribution, and the laser beam is of a flat-topped rectangular structure, so that the laser cladding device has the advantages of high cladding efficiency, high speed, low energy consumption, uniform depth distribution of a cladding layer and small heat affected zone, and can realize the rapid laser cladding of large-area spots, and improve the laser cladding efficiency and the cladding layer hardness.

The W-shaped optical field distribution enables the output spectrum of the laser to be stable, the influence of the environment is small, and the output power is stable.

The beneficial effects of the above technical scheme are: the light field distribution of each light beam in the multi-beam laser can be one or a combination of more of quasi-normal distribution, flat-top distribution or W-shaped distribution, and the superposition of the quasi-normal distribution, the flat-top distribution or the W-shaped distribution can be realized by adjusting the light field distribution of the central position and the peripheral position of each light beam in the multi-beam laser.

In one embodiment, in the step 2, the step of obtaining a welding track of the precision structural component of the power battery during the laser welding includes the following steps:

firstly, taking a picture of the precise structural member of the power battery under a strong light environment of a laboratory by N2 pictures at a position which is vertical to the precise structural member of the power battery and is N1 meters away from the middle position of the precise structural member of the power battery, wherein N1 and N2 are preset values, the value range of N1 is [0.2,0.4], and the value range of N2 is {5,6,7,8,9,10 };

Secondly, respectively preprocessing the acquired photos, wherein the preprocessing comprises image graying and Gaussian filtering, adding pixel values of corresponding positions of the N2 groups of photos, and averaging to obtain an average image img;

Then, processing the average image by using a histogram equalization technology, and performing binarization processing on the average image processed by using the histogram equalization technology to obtain a binarized image bimg, wherein a threshold value of the binarization processing needs to be determined during the binarization processing, and the determination method of the threshold value F is as follows:

Setting an initial binary threshold value formula aswhere g represents the gray scale value in the range of 0,255]img (g) is the number of gray values g, the foreground and the background of the image are determined according to the threshold, the gray value of any pixel point in the image is larger than the minimum gray value and smaller than the threshold to be the foreground, otherwise, the gray value of the pixel point is larger than the threshold and smaller than the maximum gray value to be the background, and the average gray g of the foreground is calculated_fAverage gray level g with image background_b，

wherein, g_iIs the minimum gray value, g, of all pixel points in the image_aLet F be the maximum gray value of all pixel points in the image^k＝(g_f+g_b) Average gray scale g with/2, k as foreground_faverage gray level g with background_bThe k value is increased from 0 by 1, and g is circularly calculated_fAnd g_bAnd mixing g_fand g_bSubstitution into F^k＝(g_f+g_b) /2 to calculate F^kUp to F^k+1＝F^kthen, the threshold value determination of the binarization process is completed, and the determined threshold value F is F^k；

then, using a laplacian operator to perform trajectory detection, wherein the laplacian operator of the binarized image bimg is a second-order differential, and the formula is as follows:In the two-dimensional image function, the second order difference in the x and y directions is as follows:

So that the difference form of the Laplace operator is

▽²bimg ═ bimg (x +1, y) + bimg (x-1, y) + bimg (x, y +1) + bimg (x, y-1) -4bimg (x, y), and selectedas a Laplace operation template, performing convolution operation on the Laplace operator and the binary image bimg to obtain track information;

Finally, the track coordinate information Q obtained by detection is stored_xy，x、y is respectively the horizontal coordinate value and the vertical coordinate value of the welding position, and the track coordinate information Q_xyThe formed track is the welding track in the laser welding process.

the beneficial effects of the above technical scheme are: the welding path is accurately obtained by utilizing an image processing technology, the burden of workers is greatly reduced, the welding track is obtained in advance, the follow-up laser welding work on the power battery precision machine component is facilitated, and the welding track can be planned in advance.

In one embodiment, in the step S304, the light field distribution of the central position and the peripheral position of each beam of the multi-beam laser is dynamically adjusted according to the material of the welding position to realize the dynamic adjustment of the laser energy at the welding position, wherein the calculation formula for adjusting the laser energy is as follows:

p(x,y,z)_ithe welding position is made of the adjusting laser energy value corresponding to the ith material, the value range of i is {1,2,3,4,5}, j is the number variable of the light beams in the multi-beam laser adopted by the laser welding of the precise structural member of the power battery, the value range is {1,2,3.. n }, and n is the total number of the light beams in the multi-beam laser adopted by the laser welding of the precise structural member of the power battery,Is the amplitude of the central beam of the jth beam at the origin (x is 0, y is 0, z is 0), rj is the wave number of the jth beam, andm is a preset refractive index in air, and m is approximately equal to 1, lambda_jis the wavelength of the jth beam radiation in the vacuum,is the beam waist radius of the jth laser beam, r_ihardness value of i-th material, d_iIs the texture value of the i-th material, d₁、d₂、d₃、d₄、d₅are respectively 1,2,3,4,5, f_iThe density values of the ith material are x, y and z, which are respectively an abscissa value, an ordinate value and an ordinate value.

The beneficial effects of the above technical scheme are: and dynamically and adaptively adjusting the energy value of the welding position according to the hardness, texture value and density value of different metal materials, thereby realizing the accurate control of the materials.

The invention also provides a light field distribution control system for laser welding of the precise structural member of the power battery, which comprises the following components:

A laser 101 configured to form a multi-beam laser composed of a plurality of light beams, the multi-beam laser being used as a laser used in the laser welding process;

A welding track obtaining module 102, configured to obtain a welding track of the power battery precision structural component in the laser welding process;

and the light field distribution adjusting module 103 is configured to dynamically adjust the light field distribution of each light beam in the multi-beam laser according to the welding track in the laser welding process, so as to adjust the light field distribution of the multi-beam laser.

The working principle of the technical scheme is as follows: the laser 101 forms a multi-beam laser composed of a plurality of light beams, and the multi-beam laser is used as a laser used in the laser welding process; the welding track obtaining module 102 obtains a welding track of the power battery precision structural part in the laser welding process; the light field distribution adjusting module 103 dynamically adjusts the light field distribution of each beam of the multi-beam laser according to the welding trajectory during the laser welding process, thereby adjusting the light field distribution of the multi-beam laser.

The beneficial effects of the above technical scheme are: the light field distribution adjusting module dynamically adjusts the light field distribution of each light beam in the multi-beam laser according to the welding track, and then adjusts the light field distribution of the multi-beam laser, so that the effect of the laser on the material can be dynamically and adaptively changed, the effect of controlling the temperature gradient and the stress gradient can be achieved, the problems of discontinuous materials and microcracks of a welding area in the welding process can be further avoided, and the welding quality of the precise structural member of the power battery can be effectively improved.

In one embodiment, the laser includes a multi-beam semiconductor laser, and the multi-beam semiconductor laser includes a plurality of laser oscillation regions in a stripe shape for emitting a laser beam from each of the laser oscillation regions.

the working principle of the technical scheme is as follows: the multi-beam semiconductor laser is made of gallium nitride (GaN) group III-V compound semiconductor, and the light output levels of the respective beams in the multi-beam laser are equal to each other while being easily positioned.

It should be noted that other lasers, such as gas laser, fiber laser, dye laser, etc., may be used to form a multi-beam laser that is a combination of several beams.

The beneficial effects of the above technical scheme are: with the multi-beam semiconductor laser, multi-beam laser light is formed.

In one embodiment, the welding track includes one or more of a curved line, a plurality of straight lines, or a discontinuously formed line.

the working principle of the technical scheme is as follows: the welding locus formed by the curve includes a U shape or a V shape.

The beneficial effects of the above technical scheme are: the preset welding track of the laser welding head can be obtained in the laser welding system.

In one embodiment, the light field distribution adjusting module dynamically adjusts a light field distribution function formula of the light field distribution of the multi-beam laser according to the welding track as follows:

Re(x,y)_iIs a function for regulating the optical field distribution of multi-beam laser at the welding position of the ith material, x and y are respectively the abscissa and ordinate values of the welding position, sign (x) is a symbolic functionWhen x is greater than 0, sign (x) is 1, when x is 0, sign (x) is 0, when x is less than 0, sign (x) is-1, t is a temperature value in the welding process, u is a stress value of the welding position, and p (x, y, z)_iAdjusting the laser energy value for the ith material at the welding location, the power cell precision structural member being in the same plane during welding so that the z value is a predetermined value N1 meters, p (x, y, z)_iAccording to the adjusted laser energy p (x, y, z) of different materials at different welding positions_idetermination of the formula of calculation, Q_xyis the welding track in the process of the laser welding.

the beneficial effects of the above technical scheme are: in the laser welding system, the action of laser on a material can be dynamically and adaptively changed according to the preset welding track of a laser welding head, the welding material, the temperature and stress in the welding process and the laser energy value of a welding position, so that the effect of controlling the temperature gradient and the stress gradient is achieved, the problems of discontinuous materials and microcracks of a welding area in the welding process can be further avoided, and the welding quality can be effectively improved.

it will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.