CN117655525A

CN117655525A - Automatic welding method and device for power battery connecting sheet

Info

Publication number: CN117655525A
Application number: CN202311863427.XA
Authority: CN
Inventors: 胡志能; 戚海勇; 曾春喜
Original assignee: Huizhou Zhenbang Precision Hardware Co ltd
Current assignee: Huizhou Zhenbang Precision Hardware Co ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-03-08
Anticipated expiration: 2043-12-29
Also published as: CN117655525B

Abstract

The invention is applicable to the technical field of laser welding, and provides an automatic welding method of a power battery connecting sheet, which is applied to an automatic welding control system of the power battery connecting sheet, and comprises a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module, a memory, an alarm, a processing center and an intelligent mobile terminal; the parameter presetting module, the equipment debugging module, the focus position module, the welding control module, the image acquisition module, the wireless communication module, the memory and the alarm are respectively connected with the processing center; the automatic welding device for the power battery connecting sheet is also provided. The invention automatically determines the position of the light beam focus, automatically performs laser welding and automatically detects the surface quality of the welding point, solves the problem of inaccurate laser welding point caused by inaccurate position of the light beam focus, realizes networked and intelligent automatic welding, and improves the welding efficiency.

Description

Automatic welding method and device for power battery connecting sheet

Technical Field

The invention relates to the technical field of laser welding control, in particular to an automatic welding method and device for a power battery connecting sheet.

Background

The laser welding is a high-efficiency precise welding method which uses a laser beam with high energy density as a heat source, the laser welding is mainly used for welding thin-wall materials and low-speed welding, the laser welding process belongs to heat conduction type, namely, the laser radiation heats the surface of a workpiece, the surface heat is diffused to the inside through heat conduction, and the workpiece is melted by controlling parameters such as the width, the energy, the peak power, the repetition frequency and the like of laser pulses, so that a specific molten pool is formed; the power battery connecting piece is made of a multi-layer material composite material, wherein one layer of material is a connecting layer between the connecting piece and the pole to ensure welding performance, the multi-layer material is adopted for superposition to ensure conductivity of the connecting piece, the connecting piece comprises rectangular, trapezoidal, triangular and table-shaped, nickel-plated copper foil with the thickness of 0.1 is adhered to the connecting surface, the surface is easy to oxidize and change color at high temperature during welding, and polishing and cleaning are performed under the condition that the surface coating of a product is not damaged.

In the laser welding of the existing power battery connecting sheet, the focal position of the light beam is one factor which has great influence on welding quality and is most difficult to monitor and control in welding parameters, so that the proper focal position is required to be determined by a manual adjustment and repeated process test method in production to obtain ideal penetration, but the focal position can be changed and possibly exceeds an allowable range due to workpiece deformation, thermal lens effect and space curve multidimensional welding in the welding process, thus causing inaccurate laser welding, and the accurate positioning of the focal position of the light beam is the most critical factor in the laser welding.

Disclosure of Invention

In order to solve the defects in the prior art, the invention aims to provide an automatic welding method and device for a power battery connecting sheet, which automatically determine the light beam focus position, automatically perform laser welding and automatically detect the surface quality of a welding point by setting a parameter presetting module, an equipment debugging module, a focus position module, a welding control module and an image acquisition module, solve the problem of inaccurate laser welding point caused by inaccurate light beam focus position, realize networking and intelligent automatic welding, improve the welding efficiency and reduce the welding cost.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

an automatic welding method of a power battery connecting sheet is applied to an automatic welding control system of the power battery connecting sheet, and comprises a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module, a memory, an alarm, a processing center and an intelligent mobile terminal; the parameter presetting module, the equipment debugging module, the focus position module, the welding control module, the image acquisition module, the wireless communication module, the memory and the alarm are respectively connected with the processing center; the intelligent mobile terminal comprises an intelligent mobile phone, a tablet personal computer or an intelligent remote controller, and is respectively connected with the wireless communication module in a wireless network or an internet range;

The wireless communication module is provided with various wireless network units, is responsible for receiving and transmitting wireless signals, and is connected with the intelligent mobile terminal in an effective network range in an automatic networking manner;

when the quality information of the welding surface of the battery connecting sheet is inconsistent with the quality standard of the laser welding surface stored in the memory, the alarm automatically gives an audible alarm and notifies reworking and respraying;

the memory is responsible for information storage of a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module and an alarm, and storage of a laser welding surface quality standard of the battery connecting sheet;

the processing center is responsible for information transmission of a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module, an alarm and a memory, is a system hub center, and compares the welding surface quality information of the battery connecting sheet with the laser welding surface quality standard stored in the memory: if the welding position points are inconsistent, transmitting the welding position points to an alarm and notifying the re-welding operation, and if the welding position points are inconsistent, obtaining standard parameters, and continuously welding the next position point until all the welding position points on the connecting sheet are completely welded;

The parameter presetting module is used for taking similar laser welding parameters of an industry database as preset laser welding parameters according to the material of a battery connecting sheet to be welded and the welding aperture size, and transmitting the parameters to the equipment debugging module;

the device debugging module comprises a power computing unit, a speed computing unit and a flow computing unit, and is used for debugging the laser welding device according to preset parameters to obtain optimal laser welding parameters such as laser power, welding speed, shielding gas flow and the like, and transmitting the optimal laser welding parameters to the focus position module;

the focal point position module comprises a position determining unit, a focal point adjusting unit, a focal point shape unit, a focusing adjusting unit, a coordinate calibrating unit and a focal point determining unit, and performs position calibration of the laser beam focal point by using a numerical control positioning dotting method to obtain the position of the beam focal point so as to ensure that the laser beam focal point accurately corresponds to the welding point of the connecting sheet and transmits the position to the welding control module;

the welding control module comprises a surface cleaning unit and a preheating unit, and accurately welds welding position points of a connecting sheet to be welded by using laser beams according to set technological parameters and beam focus positions so as to ensure the firmness and conductivity of the welding points and transmit the welding points to the image acquisition module;

And the image acquisition module acquires the image or video information of the surface of the welding point through the high-definition camera according to the welding completion information, converts the image or video information into welding surface quality information and transmits the welding surface quality information to the processing center.

The invention provides an automatic welding method of a power battery connecting sheet, which comprises the following steps:

s10, when the connecting sheet is subjected to laser welding, the parameter presetting module takes similar laser welding parameters of an industry database as preset laser welding parameters according to the material and the welding aperture size of the battery connecting sheet to be welded and transmits the parameters to the equipment debugging module;

s20, an equipment debugging module is used for debugging the laser welding equipment according to preset laser welding parameters to obtain optimal laser welding parameters such as laser power, welding speed, shielding gas flow and the like, and transmitting the optimal laser welding parameters to a focus position module;

s30, the focal point position module performs position calibration of the laser beam focal point through a laser controller by utilizing a numerical control positioning dotting method to obtain the position of the beam focal point so as to ensure that the laser beam focal point accurately corresponds to the welding point of the connecting sheet and transmits the welding point to the welding control module;

s40, accurately welding the welding position points of the connecting sheet to be welded by using a laser beam according to the set technological parameters and the beam focus position by the welding control module so as to ensure the firmness and the conductivity of the welding point, and transmitting the welding point to the image acquisition module;

S50, an image acquisition module acquires image or video information of the surface of the welding point through a high-definition camera according to the welding completion information, converts the image or video information into welding surface quality information and transmits the welding surface quality information to a processing center;

s60, comparing the quality information of the welding surface of the battery connecting sheet with the quality standard of the laser welding surface of the battery connecting sheet stored in the memory by the processing center: if the welding parameters are inconsistent, the welding parameters are transmitted to an alarm and the alarm is informed to carry out re-welding, if the welding parameters are consistent, the welding parameters are obtained to continue to continuously weld the next position point until all the welding position points on the connecting sheet are welded completely.

Further, the step S20 includes the following steps:

s21, the power calculation unit obtains laser welding power according to a laser welding power calculation formula ' P=E/t ', wherein P is laser welding power (W), E is energy (J) of a laser beam in a welding process, and t is welding time (S) ' and transmits the laser welding power to the speed calculation unit;

s22, a speed calculation unit calculates a formula "v=b1/b 2 v2 according to a welding speed, v is a welding speed (mm/S), b1 is a grooving width (mm), b2 is a welding head width (mm), v2 is a welding head speed (min)", and the welding head speed is transmitted to a flow calculation unit;

s23, the flow calculation unit calculates a formula Q=K×d according to the flow of the shielding gas ² * V/4, Q is the protection air flow (L/min), K is the coefficient, d is the weld diameter (mm), V is the welding speed (mm/min) "to obtain protectionGas flow rate.

Further, before "obtaining the focal position of the light beam" in the step S30, the method includes the following steps:

s301, determining an optimal focus position range around a welding hole by a position determining unit according to a welding process and the material, shape and thickness of a connecting sheet to be welded, and transmitting the optimal focus position range to a focus adjusting unit;

s302, a focus adjusting unit determines the optimal focus size by adjusting the focusing current and the focusing voltage in a focusing system of the electron beam welding machine and transmits the optimal focus size to a focus shape unit;

s303, the focus shape unit determines the optimal focus shape by changing the positions of a focusing lens and a focusing electrode of a focusing system of the electron beam welding machine, and transmits the optimal focus shape to the focus adjustment unit.

Further, the step S30 includes the following steps:

s31, paving a white paperboard on a workbench by a focusing adjustment unit, adjusting a laser focusing mirror to be 10mm smaller than a focal length, and transmitting the laser focusing mirror to a coordinate calibration unit;

s32, controlling the laser welding head to move 8-13 mm once along the X axis by the coordinate calibration unit, upwards moving 0.7-1.2 mm along the Z axis, and transmitting the laser welding head to the focus determination unit;

S33, the focus determining unit controls the laser to send a 190-210W pulse to punch holes on the paperboard, the punching is repeated for 20 times, the position of the hole with the smallest diameter is the focal position of the light beam, and the position and accuracy of the welding point are ensured.

Further, before the step S40, the method includes the following steps:

s401, removing impurities such as dirt, oxide and the like on the welding surface of the connecting sheet by the surface cleaning unit through high-speed sand jet, so that the welding surface of the connecting sheet is smoother and cleaner, and the welding surface of the connecting sheet is transferred to the material flattening unit;

s402, polishing the welding surface of the connecting sheet by a material flattening unit through polishing equipment, so that the welding surface of the connecting sheet is flatter, the welding area and the welding quality are increased, and the welding surface and the welding quality are transmitted to a preheating unit;

s403, the preheating unit controls laser to preheat the welding surface of the battery connecting sheet through the laser controller, so that the surface temperature of the connecting sheet is improved, and the welding effect and speed are improved.

Further, the step S40 further includes the following steps:

s41, protecting the welding seam by using argon, nitrogen, helium or other gases during welding by using the gas protection unit, preventing oxygen and moisture in the air from reacting with the connecting sheet to form oxides, and transmitting the oxides to the surface welding unit;

S42, carrying out laser welding on the welding point of the connecting sheet to be welded according to the position of the focal point of the light beam by the surface welding unit so as to ensure the firmness and the conductivity of the welding point, and transmitting the welding point to the post-welding treatment unit;

and S43, polishing the welding seam on the surface of the welded connecting sheet by a post-welding treatment unit through polishing equipment, removing oxides and splashes on the welding seam, and improving the smoothness and strength of the welding seam.

The invention provides an automatic welding control system for a power battery connecting sheet, which also comprises a computer readable storage medium containing a memory; the memory stores a computer program, and each functional module realizes the steps of the automatic welding method of the power battery connecting sheet when executing the computer program; the computer readable storage medium stores a computer program, and the computer program when executed by each functional module realizes the steps of the automatic welding method for the power battery connecting sheet.

The invention also provides an automatic welding device for the power battery connecting sheet, which comprises a laser controller, a laser welding head and a welding control system, and is realized by the automatic welding method for the power battery connecting sheet.

Compared with the prior art, the invention has the beneficial effects that:

through setting up parameter and predetermine module, equipment debugging module, focus position module, welding control module, image acquisition module, automatic confirm light beam focus position, automatic laser welding, automated inspection welding point surface quality, solved "because the inaccurate problem that leads to the laser welding point inaccuracy of light beam focus position", realized networking, intelligent automatic welding, improved welding efficiency, reduced welding cost.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that are required for the description of the embodiments or exemplary techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic view of a battery connecting piece according to the present invention;

FIG. 2 is a schematic diagram of a system module according to the present invention;

FIG. 3 is a schematic diagram of a device debug module according to the present invention;

FIG. 4 is a schematic view of a focal position module according to the present invention;

FIG. 5 is a schematic diagram of a welding control module according to the present invention;

FIG. 6 is a schematic diagram of a process control procedure according to the present invention;

FIG. 7 is a schematic diagram showing the process of step S20 in the process of the present invention;

FIG. 8 is a schematic diagram illustrating the procedure before step S30 in the method of the present invention;

FIG. 9 is a schematic diagram showing the process of step S30 in the process of the present invention;

FIG. 10 is a schematic diagram illustrating the procedure before step S40 in the method flow of the present invention;

fig. 11 is a schematic exploded view of step S40 in the process of the method of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The following describes in detail the implementation of the present invention in connection with specific embodiments:

in order to make the technical problems, technical schemes and beneficial effects to be solved by the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

It should be noted that when a module is referred to as being "disposed on" another module, it can be directly on the other module or be indirectly on the other module. When a module is referred to as being "connected to" another module, it can be directly connected to the other module or be indirectly connected to the other module.

In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. The meaning of "a number" is one or more than one unless specifically defined otherwise.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

Referring to fig. 1, a power battery connecting piece according to an embodiment of the present invention includes a hard portion 1, a software portion 2, and an electrode welding hole 3; the hard part 1 is a laser welding part and is connected with the welding point; the software part 2 can rotate the connecting sheet; the electrode welding hole 3 is a connecting part of the electrode and the connecting sheet after laser welding; the battery connecting piece is divided into a rectangular piece, a trapezoidal piece, a triangular piece and a table-shaped piece according to the shape, a nickel-plated copper foil with the thickness of 0.1 is stuck on the connecting surface, the surface is easy to oxidize and change color at high temperature during welding, and polishing and cleaning are carried out under the condition that the surface coating of a product is not damaged; the battery connecting piece is divided into a copper sheet, a pure nickel sheet, an iron nickel plating sheet, an aluminum nickel alloy sheet and a stainless steel sheet (see the following table in detail) according to materials, and is made of a multi-layer material composite material, wherein one layer of material is a connecting layer between a connecting piece and a pole column, so that welding performance is guaranteed, the multi-layer material is adopted to be overlapped, conductivity of the connecting piece is guaranteed, a connecting plate substrate is processed and formed after being stacked by multi-layer foils, a flexible area can be formed, displacement caused by expansion of a power battery core is compensated, and influence on a low-strength interface is reduced.

Comparison of various Material Battery connecting sheets

NO

Type(s)

Conductivity of conductive material

Resistor

Solder joint reliability

Hardness of

Toughness of

Tensile strength of

Difficulty in welding

1

Copper sheet

Good quality

33.88μΩ

Higher height

Softer and softer

Preferably

Higher height

Difficult to weld

2

Pure nickel sheet

In general

138μΩ

High height

Softer and softer

Preferably

Higher height

Easy-to-weld

3

Iron nickel plating sheet

Poor quality

195μΩ

Poor quality

Harder and harder

Difference of difference

Low/easy fracture

Is difficult to weld

4

Aluminium nickel alloy sheet

Preferably, it is

32～72μΩ

In general

Softer and softer

Good (good)

Higher height

Is difficult to weld

5

Stainless steel sheet

Difference of difference

2000μΩ

Good quality

Harder and harder

Preferably

Highest to

Easy-to-weld

Referring to fig. 2, the invention provides an automatic welding method for a power battery connecting sheet, which is applied to an automatic welding control system for the power battery connecting sheet, and comprises a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module, a memory, an alarm, a processing center and an intelligent mobile terminal; the parameter presetting module, the equipment debugging module, the focus position module, the welding control module, the image acquisition module, the wireless communication module, the memory and the alarm are respectively connected with the processing center; the intelligent mobile terminal comprises an intelligent mobile phone, a tablet personal computer or an intelligent remote controller, and is respectively connected with the wireless communication module in a wireless network or an internet range.

The wireless communication module is provided with various wireless network units, is responsible for receiving and transmitting wireless signals, and is connected with the intelligent mobile terminal in an effective network range in an automatic networking mode.

And when the quality information of the welding surface of the battery connecting sheet is inconsistent with the quality standard of the laser welding surface stored in the memory, the alarm automatically gives an audible alarm and notifies reworking and respraying.

The memory is responsible for information storage of a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module and an alarm, and storage of a laser welding surface quality standard of the battery connecting sheet.

The processing center is responsible for information transmission of a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module, an alarm and a memory, is a system hub center, and compares the welding surface quality information of the battery connecting sheet with the laser welding surface quality standard stored in the memory: if the welding parameters are inconsistent, the welding parameters are transmitted to an alarm and the alarm is informed to carry out re-welding, if the welding parameters are consistent, the welding parameters are obtained to continue to continuously weld the next position point until all the welding position points on the connecting sheet are welded completely.

Further, the laser welding surface quality standard comprises that the weld surface should be in a uniform, continuous and regular shape, and has no wave shape and no rugged; the welding seam should be even and compact, and should not have too large openings or gaps, and have no obvious defects such as air holes, slag inclusion and the like; the welding seam has good adhesiveness with the base material, no peeling, fracture and other phenomena are caused, and the welding seam and the base material are ensured to be completely fused; the appearance of the welded joint is flat, no rugged or obvious surface defect exists, the welded joint is level with the surrounding surface, and no obvious height difference exists; the surface of the welded joint has obvious weld scars or chromatic aberration, the surface of the joint is consistent with the surface of the surrounding base material, and the chromatic aberration is avoided; the surface of the welded joint should have no obvious oxidation or corrosion phenomenon, and the appearance quality of the joint should have good corrosion resistance.

The parameter presetting module is used for taking similar laser welding parameters of an industry database as preset laser welding parameters according to the material of the battery connecting sheet to be welded and the welding aperture size, and transmitting the parameters to the equipment debugging module.

Referring to fig. 3, the device debugging module includes a power calculating unit, a speed calculating unit, and a flow calculating unit, and debugs the laser welding device according to predetermined parameters to obtain optimal laser welding parameters such as laser power, welding speed, and shielding gas flow, and transmits the parameters to the focal point position module.

Further, the power calculation unit calculates a formula "p=according to the laser welding power calculation formulaE/t, P is laser welding power (W), E is energy (J) of a laser beam in a welding process, t is welding time(s), and the laser welding power is obtained and transmitted to a speed calculation unit; the speed calculation unit calculates a welding speed according to a welding speed calculation formula "v=b ₁ /b ₂ *v ₂ V is welding speed (mm/s), b ₁ Width of slot (mm), b ₂ For the width of the welding head (mm), v ₂ Is the welding head speed (min) and is transmitted to a flow calculation unit; the flow calculation unit calculates a flow calculation formula "q=k×d" according to the shielding gas flow ² * V/4, Q is the shielding gas flow (L/min), K is the coefficient, d is the weld diameter (mm), and V is the welding speed (mm/min) to obtain the shielding gas flow.

Referring to fig. 4, the focal point position module includes a position determining unit, a focal point adjusting unit, a focal point shape unit, a focus adjusting unit, a coordinate calibrating unit, and a focal point determining unit, and performs position calibration of the focal point of the laser beam by using a numerical control positioning dotting method to obtain the focal point position of the laser beam, so as to ensure that the focal point of the laser beam accurately corresponds to the welding point of the connecting piece, and transmits the focal point to the welding control module.

Further, before the "obtaining the focal position of the light beam", the method includes: the position determining unit determines the optimal focal position range around the welding hole according to the welding process and the material, shape and thickness of the connecting sheet to be welded so as to ensure the welding quality and efficiency and transmit the welding quality and efficiency to the focal point adjusting unit; the focus adjusting unit is used for determining the optimal focus size by adjusting the focusing current and the focusing voltage in a focusing system of the electron beam welding machine and transmitting the optimal focus size to the focus shape unit; the focus shape unit determines an optimal focus shape by changing a focusing lens and a focusing electrode position of a focusing system of the electron beam welding machine, and transmits the optimal focus shape to the focus adjustment unit.

Further, the "obtaining a beam focus position" includes: the focusing adjustment unit is responsible for paving a white paperboard on the workbench, adjusting the laser focusing mirror to be 10mm smaller than the focal length and transmitting the laser focusing mirror to the coordinate calibration unit; the coordinate calibration unit controls the laser welding head to move 8-13 mm once along the X axis and move 0.7-1.2 mm upwards along the Z axis, and transmits the movement to the focus determination unit; the focus determining unit controls the laser to send a 190-210W pulse to punch holes on the paperboard, and the laser is repeated for 20 times, and the position of the hole with the smallest diameter on the paperboard is the focus position of the light beam.

Referring to fig. 5, the welding control module includes a surface cleaning unit, a material leveling unit, a preheating unit, a gas protection unit, a surface welding unit, and a post-welding unit, and uses a laser beam to accurately weld the welding position points of the connecting piece to be welded according to the set process parameters and the beam focus position, so as to ensure the firmness and conductivity of the welding point, and transmits the welding point to the image acquisition module.

Before the welding position points of the connecting sheet to be welded are accurately welded by using laser beams, the surface cleaning unit cleans impurities such as dirt, oxide and the like on the welding surface of the connecting sheet by spraying sand at a high speed, so that the welding surface of the connecting sheet is smoother and cleaner, the welding quality is improved, and the impurities are transferred to the material flattening unit; the material flattening unit polishes the welding surface of the connecting sheet through polishing equipment, so that the welding surface of the connecting sheet is flatter, the welding area and the welding quality are increased, and the welding surface and the welding quality are transmitted to the preheating unit; the preheating unit controls laser to preheat the welding surface of the battery connecting sheet through the laser controller, so that the surface temperature of the connecting sheet is increased, and the welding effect and speed are improved.

The gas protection unit protects a welding line by using argon, nitrogen, helium or other gases during welding, prevents oxygen and moisture in air from reacting with the connecting sheet to form oxides, and transmits the oxides to the surface welding unit; the surface welding unit performs laser welding on the welding point of the connecting sheet to be welded according to the position of the light beam focus so as to ensure the firmness and the conductivity of the welding point and transmits the welding point to the post-welding treatment unit; the post-welding treatment unit polishes the welding line on the surface of the post-welding connecting piece through polishing equipment, removes oxides and splashes on the welding line, and improves the smoothness and strength of the welding line.

System operation theory:

when the battery connecting sheet is subjected to laser welding, the parameter presetting module takes similar laser welding parameters of an industry database as preset laser welding parameters according to the material and the size of the battery connecting sheet and transmits the parameters to the equipment debugging module; the laser welding device is debugged by the device debugging module according to preset parameters to obtain optimal laser welding parameters such as laser power, welding speed, shielding gas flow and the like, and the optimal laser welding parameters are transmitted to the focal point position module, wherein the laser welding parameters comprise that the laser welding power is obtained by a power computing unit according to a laser welding power computing formula ' P=E/t ', P is laser welding power (W), E is energy (J) of a laser beam in a welding process, and t is welding time(s) ' and transmitted to a speed computing unit; the control speed calculation unit calculates a welding speed according to a welding speed calculation formula "v=b ₁ /b ₂ *v ₂ V is welding speed (mm/s), b ₁ Width of slot (mm), b ₂ For the width of the welding head (mm), v ₂ Is the welding head speed (min) and is transmitted to a flow calculation unit; according to a protective gas flow calculation formula Q=K×d by a flow calculation unit ² * V/4, Q is the protective gas flow (L/min), K is a coefficient, d is the weld diameter (mm), and V is the welding speed (mm/min) to obtain the protective gas flow;

the control focus position module performs position calibration of a laser beam focus by using a numerical control positioning dotting method to obtain a beam focus position so as to ensure that the laser beam focus accurately corresponds to a welding point of a connecting sheet and is transmitted to a welding control module, and the control module comprises: the white paper board is paved on a workbench through a focusing adjustment unit, and a laser focusing mirror is adjusted to be 10mm smaller than the focal length and is transmitted to a coordinate calibration unit; the control coordinate calibration unit controls the laser welding head to move 8-13 mm once along the X axis and move 0.7-1.2 mm upwards along the Z axis, and transmits the movement to the focus determination unit; the laser is controlled by the focus determining unit to send a 190-210W pulse to punch holes on the paperboard, and the holes are repeated for 20 times, and the position of the smallest diameter hole on the paperboard is the focal position of the light beam;

accurately welding the welding position points of the connecting sheet to be welded by using laser beams according to set technological parameters and the beam focus positions through a welding control module so as to ensure the firmness and the conductivity of the welding points, and transmitting the welding points to an image acquisition module, wherein the welding control module comprises: the surface cleaning unit cleans the surface of the battery connecting sheet to remove various foreign matters and impurities and transmits the foreign matters and impurities to the preheating treatment unit; then the preheating processing unit controls the laser to preheat the contact surface of the battery connecting sheet through the laser controller, so that the welding effect and speed are improved; acquiring image or video information of the surface of the welding point through a high-definition camera according to the welding completion information through an image acquisition module, converting the image or video information into welding surface quality information, and transmitting the welding surface quality information to a processing center; the control processing center compares the welding surface quality information with the laser welding surface quality standard stored in the memory: if the welding parameters are inconsistent, the welding parameters are transmitted to an alarm and the alarm is informed to carry out re-welding, if the welding parameters are consistent, the welding parameters are obtained to continue to continuously weld the next position point until all the welding position points on the connecting sheet are welded completely.

When an operator or manager goes outdoors or goes on business, the intelligent mobile phone or the tablet personal computer can be connected with the wireless communication module in the wireless network or the Internet in an automatic networking mode, and the running state of laser welding of the connecting sheet can be controlled remotely, so that networking and intelligent control can be realized, and welding efficiency and management efficiency are improved.

Referring to fig. 6, the invention provides an automatic welding method for a power battery connecting sheet, comprising the following steps:

further, the preset laser welding parameters comprise different welding parameters for the material of the battery connecting sheet to be welded and the welding aperture size; acquiring industry parameter library data through networking various network platforms and an industry database; and matching the optimal welding parameters according to the optimal welding parameters in the laser welding industry of the power battery connecting sheet, and preparing for determining the optimal welding parameters for the subsequent trial welding regulator.

Furthermore, the welding speed and the flow of the shielding gas belong to parameters which are easy to monitor and keep stable, and the laser power and the focal position of the light beam are parameters which are difficult to monitor due to fluctuation possibly occurring in the welding process; although the laser power output by the laser has high stability and is easy to monitor, the laser power reaching the workpiece can be changed due to the loss of the light guide and focusing system, and the loss is related to the quality, the service time and the surface pollution condition of the optical workpiece, so the laser power is not easy to monitor and becomes an uncertain factor of welding quality; beam focal position is one factor in welding parameters that has a great impact on weld quality and is most difficult to monitor and control. The effect on the form of the welding process and the stabilizer is not as remarkable as that of the laser power and the focal position, and only when the welding speed is too high, the stable deep penetration welding process cannot be maintained due to the fact that the heat input is too small. In actual welding, stable deep penetration welding or stable thermal conduction welding is selected according to the requirement of the weldment on penetration, and unstable welding modes are absolutely avoided.

S40, accurately welding the welding point of the connecting sheet to be welded by using a laser beam according to the set technological parameters and the beam focus position by the welding control module so as to ensure the firmness and the conductivity of the welding point, and transmitting the welding point to the image acquisition module;

further, if the surface of the connecting sheet is made of aluminum alloy, the reflectivity to laser is extremely high, the sensitivity to air holes is high in the welding process, and the air holes, the hot cracks and the explosion fire are inevitably generated in the welding process; the air holes are formed in the surface of the aluminum alloy connecting sheet, which is easily generated by the collapse of hydrogen holes or bubbles in the laser welding process, and the problem of the hydrogen holes is more serious because the cooling speed of the laser welding is too high, and holes which are generated by the collapse of small holes are also formed in the laser welding; the hot cracking refers to that when the surface of a connecting sheet of aluminum alloy is welded, eutectic segregation occurs due to the component segregation of a welding area, so that the crystal boundary is melted, and a welding line crystal crack or a HAZ liquefied crack is easily formed at the crystal boundary under the action of stress, so that the performance of a welded joint is reduced; the fire explosion, also called splashing, refers to that a certain splashing is generated when the connecting sheet of the aluminum alloy is welded in the thickness of 1.0mm, and the connecting sheet is caused by the reasons of material purity, surface cleanliness, material characteristics and the like.

S50, an image acquisition module acquires image or video information of the surface of the welding point through a high-definition camera according to the welding completion information, converts the image or video information into quality information of the laser welding surface of the battery connecting sheet, and transmits the quality information to a processing center;

further, the high-definition camera is an infrared high-definition camera with 360 degrees, the definition is not limited by the intensity of light during photographing, 360 degrees of all-round photographing can be carried out without being separated from day and night and without being separated from lamplight, images of different position points of each welding hole can be identified from a plurality of different angles, the different position points of each welding hole are identified by different angles, further, the different position points and the shapes of each welding hole can be identified and obtained more accurately and comprehensively, or based on images of different position points of a plurality of the same welding holes obtained from different angles, the different position points of each welding hole are identified through multi-angle matching, and then the welding surface shape of each welding hole is determined.

S60, comparing the quality information of the laser welding surface of the battery connecting sheet with the quality standard of the laser welding surface stored in the memory by the processing center: if the welding points are inconsistent, the welding points are transmitted to an alarm and are notified to be reworked, if the welding points are consistent, the welding points are qualified, standard parameters are obtained, and continuous welding is continued on the next position point until all the welding position points on the connecting sheet are completely welded.

Further, the qualification of the laser welding point means that the battery connecting sheet meets the quality of the laser welding surface, including that the surface of the welding line is in a uniform, continuous and regular shape without wave and uneven; the welding seam should be even and compact, and should not have too large openings or gaps, and have no obvious defects such as air holes, slag inclusion and the like; the welding seam has good adhesiveness with the base material, no peeling, fracture and other phenomena are caused, and the welding seam and the base material are ensured to be completely fused; the appearance of the welded joint is flat, no rugged or obvious surface defect exists, the welded joint is level with the surrounding surface, and no obvious height difference exists; the surface of the welded joint has obvious weld scars or chromatic aberration, the surface of the joint is consistent with the surface of the surrounding base material, and the chromatic aberration is avoided; the surface of the welding joint has no obvious oxidation or corrosion phenomenon, and the appearance quality of the joint has good corrosion resistance; the surface of the welding point is free from any foreign matters or dirt.

Referring to fig. 7, the step S20 includes the following steps:

Further, the laser power refers to the amount of laser radiation energy in unit time, and is influenced by the type and thickness of the material, the width and depth of the welding seam, the welding speed, the welding position, the diameter and focusing of the laser beam, and as different materials are welded, different powers are required, if the thickness is larger, the required power is larger; because different power is required for welds of different sizes, a deeper, wider weld requires higher power; the faster the welding speed, the higher the power required; as some locations require higher power to complete the weld; since the smaller the diameter of the laser beam, the higher the power density, the smaller the power required, and the better the focusing effect, the smaller the power required.

S22, the speed calculation unit calculates a formula "v=b" according to the welding speed ₁ /b ₂ *v ₂ V is welding speed (mm/s), b ₁ Width of slot (mm), b ₂ For the width of the welding head (mm), v ₂ Is the welding head speed (min) and is transmitted to a flow calculation unit;

further, the welding speed refers to the length of a welding seam completed in unit time, so that the heat input in unit time can be influenced, the penetration depth can be reduced due to high welding speed, and the welding of a workpiece is not transparent; the welding speed is slow, so that the workpiece is possibly penetrated and welded due to excessive melting, and in the deep penetration welding range, the influence of welding parameters on penetration: in the stable deep penetration welding range, the higher the laser power is, the greater the penetration is, and the relationship is about 0.7 power; the higher the welding speed is, the shallower the penetration is, the maximum penetration is when the focus is at the optimal position under the conditions of a certain laser power and welding speed, and the penetration is reduced even becomes mode unstable welding or stable thermal conduction welding when the focus is deviated from the optimal position.

Further, the grooving width is a groove left on the surface of the material by a welding head, and the number speed of the welding head is related to parameters such as laser power density, welding depth and the like.

S23, the flow calculation unit calculates a formula Q=K×d according to the flow of the shielding gas ² * V/4, Q is the shielding gas flow (L/min), K is the coefficient, d is the weld diameter (mm), and V is the welding speed (mm/min) to obtain the shielding gas flow.

Furthermore, the flow rate of the protective gas refers to that the laser welding machine uses inert gases such as helium, argon, nitrogen and the like for protection, the price of the helium is high, but the protection effect is best, the price of the argon is low, the protection effect is better, and the price of the nitrogen is the lowest, but partial materials are not applicable; the shielding gas is used for protecting the workpiece from oxidation during the welding process; the focusing lens is protected from metal vapor pollution and sputtering of liquid droplets; dispersing plasma generated by high-power laser welding; and cooling the workpiece to reduce the heat affected zone. The shielding gas is usually argon or helium, and nitrogen can be used with low apparent mass requirements. Their propensity to generate plasma varies significantly: helium has high ionization current and high heat conduction speed, and has smaller tendency than argon to generate plasma under the same conditions, so that larger penetration can be obtained. In a certain range, the tendency to suppress plasma increases with an increase in the flow rate of the shielding gas, and the penetration increases, but the plasma tends to be stable when the flow rate increases to a certain range.

Referring to fig. 8, before "obtaining the focal position of the light beam" in the step S30, the method includes the following steps:

s301, determining an optimal focal position range around a welding hole by a position determining unit according to a welding process and the material, shape and thickness of a connecting sheet to be welded so as to ensure the welding quality and efficiency, and transmitting the optimal focal position range to a focal point adjusting unit;

Further, the verification of the focus adjustment can be confirmed through a subsequent welding test result, the effect of the focus adjustment is judged through the shape and welding quality of a welding joint, if the shape and welding quality of the welding joint meet the requirements, the focus adjustment is correct, and if the shape and welding quality of the welding joint do not meet the quality requirements, the focus adjustment needs to be adjusted.

Referring to fig. 9, the step S30 includes the following steps:

Further, the position of the beam focus refers to the optimal focus position of the beam, which can obtain an optimal welding seam when the beam focus is positioned at a position below the surface of the workpiece within a range of 1-2 mm, and if the beam focus is deviated from the position, the light spot on the surface of the workpiece becomes larger, so that the power density becomes smaller, and the welding process form is changed to a certain range.

Referring to fig. 10, before the step S40, the method includes the following steps:

s401, removing impurities such as dirt and oxide on the welding surface of the connecting sheet by the surface cleaning unit through high-speed sand spraying, so that the welding surface of the connecting sheet is smoother and cleaner, the welding quality is improved, and the welding quality is transferred to the material flattening unit;

Referring to fig. 11, the step S40 further includes the following steps:

Further, the invention is described in terms of the implementation of a software program for a power battery tab automatic welding control system, wherein the method implemented for each control system is divided into a plurality of modules or units, and software program instructions generated by each step are implemented, and the software program instructions comprise the automatic welding method for a power battery tab described above. The implementation of the above procedure is mostly automated, although a small part of the actions are semi-automated, and a small part of the actions need manual assistance to be completed.

Further, the computer program is divided into a plurality of modules/units which are stored in the memory and executed by the respective modules/units to complete the present invention; the modules/units may be a series of computer program instructions capable of performing a specified function, for describing the execution of the computer program in each of the modules/units.

It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Finally, it should be noted that the foregoing embodiments are merely for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present application, and are included in the protection scope of the present application.

Claims

1. An automatic welding method of a power battery connecting sheet is characterized by comprising the following steps of: the automatic welding control system comprises a parameter presetting module, an equipment debugging module, a focus position module, a welding control module, an image acquisition module, a wireless communication module, a memory, an alarm, a processing center and an intelligent mobile terminal; the parameter presetting module, the equipment debugging module, the focus position module, the welding control module, the image acquisition module, the wireless communication module, the memory and the alarm are respectively connected with the processing center; the intelligent mobile terminal comprises an intelligent mobile phone, a tablet personal computer or an intelligent remote controller, and is respectively connected with the wireless communication module in a wireless network or an internet range;

The parameter presetting module is used for taking similar laser welding parameters of an industry database as preset laser welding parameters according to the material and the size of the battery connecting sheet and referring to the similar laser welding parameters of the industry database, and transmitting the parameters to the equipment debugging module;

the focal point position module comprises a focusing adjustment unit, a coordinate calibration unit and a focal point determination unit, and performs position calibration of a laser beam focal point by using a numerical control positioning dotting method to obtain a beam focal point position so as to ensure that the laser beam focal point accurately corresponds to a welding point of the connecting sheet and is transmitted to the welding control module;

2. The automatic welding method of the power battery connecting sheet according to claim 1, wherein: the method comprises the following steps:

s10, when the connecting sheet is subjected to laser welding, the parameter presetting module takes similar laser welding parameters of an industry database as preset laser welding parameters according to the material and the size of the battery connecting sheet and transmits the parameters to the equipment debugging module;

3. The automatic welding method of the power battery connecting sheet according to claim 2, wherein: the step S20 includes the steps of:

s22, the speed calculation unit calculates a formula "v=b" according to the welding speed ₁ /b ₂ *v ₂ V is welding speed (mm/s), b ₁ Width of slot (mm), b ₂ For the width of the welding head (mm), v ₂ For weldingHead speed (min) ", and transferred to the flow rate calculation unit;

4. The automatic welding method of the power battery connecting sheet according to claim 2, wherein: before "obtaining the focal position of the light beam" in the step S30, the method includes the following steps:

5. The automatic welding method of the power battery connecting sheet according to claim 2, wherein: the step S30 includes the steps of:

S33, the focus determining unit controls the laser to send a 190-210W pulse to punch holes on the paperboard, the punching is repeated for 20 times, the position of the smallest diameter hole on the paperboard is the focus position of the light beam, and the position and accuracy of the welding point are ensured.

6. The automatic welding method of the power battery connecting sheet according to claim 2, wherein: before the step S40, the method includes the following steps:

7. The automatic welding method of the power battery connecting sheet according to claim 2, wherein: the step S40 further includes the steps of:

8. The automatic welding method of the power battery connecting sheet according to claim 1, wherein: the automatic welding control system for the power battery connecting sheet also comprises a computer readable storage medium containing a memory; the memory stores a computer program, and each functional module implements the steps of the automatic welding method for the power battery connecting piece according to any one of the claims 2 to 7 when executing the computer program; the computer-readable storage medium stores a computer program which, when executed by each functional module, implements the steps of a method for automatically welding a power battery connection piece according to any one of claims 2 to 7.

9. The utility model provides a power battery connection piece automatic welder includes laser controller, laser welding head, welding control system, its characterized in that: an automatic welding method of a power battery connecting sheet according to the claims 1-8.