CN-117680814-B - Welding method and welding system for battery shell

CN117680814BCN 117680814 BCN117680814 BCN 117680814BCN-117680814-B

Abstract

The invention relates to a welding method and a welding system for a battery shell, wherein the shell comprises a shell body used for surrounding a battery core and a cover plate used for closing the end part of the shell body, the welding method is used for welding the cover plate and the shell body, the welding method comprises the steps of obtaining a welding path and dividing the welding path into at least a first section and a second section which are connected in sequence, controlling a welding head to weld at a constant speed in the first section, and controlling the welding head to start from the end point of the first section to weld at a uniform speed in the second section. When the battery shell and the cover plate are welded, the welding speed of the second section is equal to the uniform acceleration which is larger than that of the first section, so that the laser energy input of the welding head to the rear section part can be reduced, namely the line energy is reduced. Even if the welding heat of the front section is accumulated to the rear section, the consistency of penetration of the front section and the rear section of the welding path is guaranteed to be good, so that the welding yield of the battery shell is high, and the welding quality is good.

Inventors

HUANG YEWEN
XING WENQING
LIU MENG

Assignees

惠州比亚迪电池有限公司

Dates

Publication Date: 20260505
Application Date: 20220902

Claims (14)

1. A welding method of a battery case including a case for surrounding a periphery of a battery cell and a cap plate for closing an end of the case, the welding method being for welding the cap plate with the case, characterized by comprising: Acquiring a welding path and dividing the welding path into at least a first section and a second section which are connected in sequence; controlling the welding head to weld at constant speed in the first section, and Controlling the welding head to uniformly accelerate welding in the second section from the end point of the first section; The step of obtaining a welding path and dividing the welding path into at least a first section and a second section which are connected in sequence comprises the steps of setting the ratio of the distance of the first section to the distance of the second section to be 1:3-3:1, and setting the ratio of the speed of the second section to the speed of the first section to be 1.05-1.3; The welding method comprises the following steps: After the step of obtaining a welding path and dividing the welding path into at least a first section and a second section connected in sequence, setting a start section before the first section and an end section after the second section; Before the step of controlling the welding head to weld at a constant speed in the first section, controlling the welding head to accelerate to a first speed in the initial section, wherein the first speed is the welding speed of the welding head in the first section, and And after the step of controlling the welding head to uniformly accelerate welding in the second section from the end point of the first section, controlling the welding head to decelerate to zero in the end section.
2. The welding method of claim 1, comprising obtaining a defocus amount of the welding head at the initiation section and adjusting the defocus amount of the welding head to a preset defocus amount.
3. The welding method according to claim 1, wherein the cover plate is square in configuration and includes four sides, and a rounded corner is provided between each two adjacent sides, and the step of obtaining a welding path and dividing the welding path into at least a first section and a second section connected in sequence includes: And setting the starting point of the first section at the tangential point of the round corner at one end of the side to be welded and the side to be welded, and setting the ending point of the second section at the middle position of the round corner at the other end of the side to be welded.
4. The welding method according to claim 1, characterized in that the welding method comprises: Acquiring the offset of the position information of the welding path and preset position information before welding by the welding head, and And controlling the welding head to move according to the offset.
5. The welding method according to any one of claims 1 to 4, wherein before the step of acquiring a welding path and dividing the welding path into at least a first segment and a second segment connected in sequence, the welding method comprises: Controlling a clamping mechanism to clamp the housing, and And controlling the pressing mechanism to press the cover plate.
6. The welding method of claim 1, wherein the cover plate includes four sides, the welding method comprising: After the welding head finishes welding one side edge in a preset welding area, controlling the welding head to return to the initial position, and The battery case is controlled to rotate such that the other non-welded side edge is rotated to the welding area.
7. A welding system, characterized in that the battery housing can be welded using the welding method of any one of claims 1-6, the welding system comprising: the welding head is used for emitting laser; A driving mechanism for driving the welding head to move, and And the control module is used for controlling the driving speed of the driving mechanism.
8. The welding system of claim 7, comprising a first mount for mounting the battery housing, the first mount having a CCD camera mounted thereon for acquiring positional information of the welding path, the control module being electrically connected to the CCD camera.
9. The welding system of claim 7, comprising a ranging sensor fixed in position relative to the welding head for measuring an amount of defocus of the welding head, the control module being electrically connected to the ranging sensor.
10. The welding system of claim 7, comprising a mounting platform for passing the battery enclosure therethrough and a clamping mechanism for clamping the housing to the mounting platform, the clamping mechanism comprising: A clamping member slidably mounted on the mounting platform, capable of being moved closer to or farther from a surface of the housing; an elastic member elastically pressed against between the mounting platform and the clamping member for pressing the clamping member against the surface of the housing, and The first linear driving mechanism is arranged on the mounting platform and connected with the clamping piece and used for overcoming the elastic force of the elastic piece to drive the clamping piece to be far away from the surface of the shell.
11. The welding system of claim 10, wherein the mounting platform has a square-shaped via formed therethrough, two adjacent edges of the square-shaped via each having a retaining wall extending outwardly for engaging corresponding two adjacent surfaces of the battery housing, the clamping mechanism including a first clamping mechanism for clamping the housing against one of the retaining walls and a second clamping mechanism for clamping the housing against the other of the retaining walls.
12. The welding system of claim 7, comprising a hold-down mechanism mounted to the first mount, the hold-down mechanism comprising a hold-down member for pressing against a surface of the cover plate and a second linear drive mechanism for driving the hold-down member toward or away from the cover plate, an outer contour of the hold-down member in contact with the cover plate being within an outer contour of the cover plate.
13. The welding system of claim 12, wherein the welding system comprises a mounting platform for mounting the battery housing, the mounting platform being rotatably mounted on the first mount, the hold-down mechanism comprising a rotary drive mechanism, the hold-down member being mounted at an output of the rotary drive mechanism for synchronous rotation with the mounting platform by the rotary drive mechanism, the rotary drive mechanism being mounted at an output of the second linear drive mechanism for driving the hold-down member toward or away from the cover plate by the second linear drive mechanism.
14. The welding system of claim 7, wherein the welding system is two for welding at the cover plates at both ends of the housing, respectively.

Description

Welding method and welding system for battery shell Technical Field The disclosure relates to the technical field of battery manufacturing, in particular to a welding method and a welding system for a battery shell. Background Square batteries are being developed in the directions of longer length and smaller thickness to have a larger heat dissipation area and better safety performance. Currently, such batteries are typically over 1000mm in length and less than 13.5mm in thickness, while the thickness of the outer casing is typically no greater than 0.3mm, e.g., the thickness of the aluminum casing is typically no greater than 0.3mm, and the thickness of the steel casing is typically no greater than 0.2mm. In the welding process, heat input of the front welding part can be transmitted to the welding seam position which is not welded at the rear part, so that the penetration of the welding seam is inconsistent, and the welding quality of the battery shell is poor due to the fact that the shell is thinner. Disclosure of Invention It is an object of the present disclosure to provide a welding method and a welding system of a battery case to at least partially solve the problems in the related art. In order to achieve the aim, the invention provides a welding method of a battery shell, the shell comprises a shell body used for surrounding the periphery of a battery cell and a cover plate used for closing the end part of the shell body, the welding method is used for welding the cover plate and the shell body, the welding method comprises the steps of obtaining a welding path and dividing the welding path into at least a first section and a second section which are connected in sequence, controlling a welding head to weld at a uniform speed in the first section, and controlling the welding head to accelerate welding at a uniform speed in the second section from the end point of the first section. Optionally, the step of obtaining the welding path and dividing the welding path into at least a first section and a second section which are connected in sequence comprises the steps of setting the ratio of the distance of the first section to the distance of the second section to be 1:3-3:1, and setting the ratio of the speed of the second section to the speed of the first section to be 1.05-1.3. Optionally, the welding method includes: After the step of obtaining a welding path and dividing the welding path into at least a first section and a second section connected in sequence, setting a start section before the first section and an end section after the second section; Before the step of controlling the welding head to weld at a constant speed in the first section, controlling the welding head to accelerate to a first speed in the initial section, wherein the first speed is the welding speed of the welding head in the first section, and And after the step of controlling the welding head to uniformly accelerate welding in the second section from the end point of the first section, controlling the welding head to decelerate to zero in the end section. Optionally, the welding method comprises obtaining the defocus amount of the welding head in the initial section and adjusting the defocus amount of the welding head to a preset defocus amount. Optionally, the welding method includes: and reading the defocusing amount of the welding head in real time in the welding path and adjusting the defocusing amount of the welding head to a preset defocusing amount. Optionally, the cover plate is configured as a square and includes four sides, and a rounded corner is disposed between every two adjacent sides, and the step of obtaining a welding path and dividing the welding path into at least a first section and a second section connected in sequence includes: And setting the starting point of the first section at the tangential point of the round corner at one end of the side to be welded and the side to be welded, and setting the ending point of the second section at the middle position of the round corner at the other end of the side to be welded. Optionally, the welding method includes: Acquiring the offset of the position information of the welding path and preset position information before welding by the welding head, and And controlling the welding head to move according to the offset. Optionally, before the step of acquiring a welding path and dividing the welding path into at least a first segment and a second segment connected in sequence, the welding method includes: Controlling a clamping mechanism to clamp the housing, and And controlling the pressing mechanism to press the cover plate. Optionally, the cover plate includes four sides, and the welding method includes: After the welding head finishes welding one side edge in a preset welding area, controlling the welding head to return to the initial position, and The battery case is controlled to rotate such that the other non-welded side edge is rotated to the weld