Guide insulation sleeve and spot welding machine using same

Abstract

The invention provides a guide insulation sleeve (12) and a spot welder (1) using the same. The guide insulation sleeve (12) is used for guiding and insulating a welding rod (7) of a spot welding machine (1) and is characterized in that the guide insulation sleeve (12) is sequentially provided with a square base (121), a sleeve (122) and a center correction guide hole (123) from top to bottom, a cavity (12a) is formed in the square base (121) and the sleeve (122), and the cavity (12a) and a mounting seat (7a) of the welding rod (7) can form a clearance sliding matching structure; the center correction guide hole (123) is arranged on the lower surface of the sleeve (122) in an extending mode and is in a hollow pipe shape, a hollow hole (12b) is formed in the center correction guide hole (123), and an electrode (7b) of the welding rod (7) can be inserted into the hollow hole (12b). By adopting the spot welding machine (1) with the guide insulating sleeve (12), the shaking and inclination of the welding rod (7) in the welding of the bottom of the battery can be effectively inhibited, and the external short shunt during welding is avoided.

Description

Technical Field

[0001] The present invention relates to a guiding insulating sleeve and a spot welder using the same. Background Art

[0002] A spot welder adopts the principle of resistance welding. The upper and lower electrodes are connected through welding rods. The welding current flows through the joint of the workpieces. Heat is generated by the resistance of the workpieces themselves, melting the metal at the joint of the workpieces, thereby forming a welded joint. In the production of batteries, the spot welder is used for welding the bottom of cylindrical batteries, that is, inserting the welding rod into the central hole of the wound core of the battery, and conducting the welding current between the upper and lower electrodes, thereby welding the negative lead of the core to the bottom of the battery case. The spot welders on the market are developing towards the direction of automation, intelligence, and high precision.

[0003] In order to improve the welding quality and production stability of battery bottom welding, a spot welder usually has a guiding sleeve for accurately positioning and guiding the displacement of the welding rod to ensure that the welding rod can be aligned with the target position during the welding process.

[0004] Figure 7 is a three-dimensional structure diagram of the welding rod (7) used in the spot welder. As Figure 7 shown, one end of the welding rod (7) is a cylindrical mounting seat (7a), and the other end is a rod-shaped electrode (7b).

[0005] Figure 8 is a top view of the battery (10) to be welded. The battery (10) has a wound core (10a) and a battery case (10c) with one end open. As Figure 8 shown, the wound core (10a) has a central hole (10b) at its axial center.

[0006] Figure 9 is a schematic structural diagram of a spot welder used in the prior art. As Figure 9 shown, the spot welder (1) includes a frame (2), an upper electrode (4), a lower electrode (5), and a guiding sleeve (6) connected to the frame (2) through an electrode arm (3). The guiding sleeve (6) is located between the upper and lower electrodes (4, 5), and the welding rod (7) is inserted into the guiding sleeve (6). In addition, a pressure sensor (8) and a pressing head (9) are provided above the upper electrode (4), and the battery (10) to be welded is located between the welding rod (7) and the lower electrode (5). The control system (not shown) of the spot welder (1) can control the movement of the welding rod (7) through the guiding sleeve (6).

[0007] When performing bottom welding of a battery, first, the lower electrode (5) jacks up to contact the bottom of the battery (10), and the guide sleeve (6) presses down with the welding rod (7), inserting the electrode (7b) of the welding rod (7) into the central hole (10b) of the battery (10). Then, the pressure head (9) presses the upper electrode (4) downward under the control of the motion servo system, making the upper electrode (4) conduct through the welding rod (7) with the lower electrode (5), so as to perform welding under pressure.

[0008] Figure 10 is a schematic structural diagram of the guide sleeve (6) used in spot welding of the prior art. As Figure 10 shown in the perspective view of (a), the guide sleeve (6) includes a square base (61) above and a cylindrical sleeve (62) below. The square base (61) or the sleeve (62) can be connected to an external control device through an electrode arm. As Figure 10 shown in the cross-sectional view of (b), the guide sleeve (6) has a cylindrical cavity (6a) in the central part, and the circumferential surface of the cavity (6a) constitutes a positioning surface. The cylindrical mounting seat (7a) of the welding rod (7) can slide freely up and down in the cavity (6a).

[0009] Figure 11 shows a schematic diagram of the usage state of the guide sleeve (6) of the prior art; (a) shows the initial state before the welding rod is inserted into the battery cell; (b) shows the final state after the welding rod is inserted into the battery cell; (c) shows the welding state.

[0010] As Figure 11 shown, the problem existing in the prior art is that: between the mounting seat (7a) of the welding rod and the cavity (6a) of the guide sleeve is a clearance sliding fit structure. When the welding rod (7) is in the Figure 11 final state after being inserted into the battery cell as shown in (b), the mounting seat (7a) of the welding rod (7) extends out of the square base (61) for a long distance, and the positioning surface of the cavity (6a) of the guide sleeve (6) for the mounting seat (7a) of the welding rod (7) is reduced. Therefore, the welding rod (7) is prone to shaking and tilting. If the welding rod (7) shakes and tilts, it will cause unstable contact between the welding rod (7) and the bottom of the battery case and the negative lead (not shown) in the welding state, easily resulting in solder joint offset and unstable discharge current. Furthermore, as Figure 11 shown in (c), when the inner bending angles of the positive current collectors above the wound battery cell (10a) are inconsistent, the positive lead (11) is likely to contact the electrode (7b) of the welding rod (7), resulting in external short-circuit shunting and causing a low-current alarm. Summary of the Invention

[0011] Technical Problem to be Solved by the Invention

[0012] The present invention is made in view of the above problems, and aims to provide a guiding insulating sleeve with a novel structure and a spot welder using the same. By using the spot welder with the guiding insulating sleeve in the bottom welding of the battery, the shaking and inclination of the welding rod can be effectively suppressed, and external short-circuit shunting during welding can be avoided.

[0013] Means for Solving the Technical Problem

[0014] The guiding insulating sleeve (12) of the present invention is used to guide and insulate the welding rod (7) of the spot welder (1), and is characterized in that it sequentially includes a square base (121), a sleeve (122), and a center alignment guiding hole (123) from top to bottom.

[0015] The square base (121) and the sleeve (122) have a cavity (12a) inside, and can form a clearance sliding fit structure with the mounting seat (7a) of the welding rod (7).

[0016] The center alignment guiding hole (123) is extendably provided on the lower surface of the sleeve (122), is a hollow tubular shape, and has a hole (12b) inside. The electrode (7b) of the welding rod (7) can be inserted into the hole (12b).

[0017] Preferably, the square base (121) has a base portion (121a) and two side walls (121b) extending upward from both sides of the base portion (121a), and a notch (121c) is formed between the two side walls (121b).

[0018] Preferably, when the height of the base portion (121a) of the square base (121) is set as H 0 、the height of the sleeve (122) is H 1 、the height of the mounting seat (7a) of the welding rod (7) is H 3 , then H 3 = H 0 + H 1 .

[0019] Preferably, when the height of the side wall (121b) of the square base (121) is set as H 2 、the length of the electrode (7b) of the welding rod (7) is L 3 、the height of the battery (10) to be welded is L 2 、the extension length of the center alignment guiding hole (123) is L 1 , then L 1 < L 3 - L 2 - H 2 .

[0020] Preferably, the diameter Φ of the hollow hole (12b) of the center alignment guide hole (123) 空孔 and the outer diameter Φ of the electrode (7b) of the welding rod (7) 电极 The difference, namely Φ 空孔 -Φ 电极 is in the range of 0.02 to 0.10 mm.

[0021] Preferably, a guide conical surface (123a) inclined inward is formed at the lower end of the center alignment guide hole (123), and its guide angle is 4 to 15°.

[0022] Preferably, the center alignment guide hole (123) is formed of an insulating material.

[0023] The spot welder (1) of the present invention is used for bottom welding of the battery (10), and the battery (10) includes a wound core (10a) and a battery case (10c) with one end open. It is characterized in that

[0024] it at least includes an upper electrode (4), a lower electrode (5), a welding rod (7), a pressure head (9), a detection system, a control device, and the guide insulating sleeve (12) according to any one of claims 1 to 7,

[0025] The detection system detects the position of the center hole (10b) of the wound core (10a) and the position of the welding rod (7);

[0026] The welding rod (7) is inserted into the guide insulating sleeve (12),

[0027] The guide insulating sleeve (12) is connected to the control device,

[0028] The control device controls the displacement of the welding rod (7) through the guide insulating sleeve (12) according to the detection result of the detection system, so as to insert the electrode (7b) of the welding rod (7) into the center hole (10b) of the wound core (10a),

[0029] When the electrode (7b) of the welding rod (7) reaches the bottom of the battery case (10c), the pressure head (9) drives the upper electrode (4) to move downward, and conducts through the welding rod (7) and the lower electrode (5), and applies a welding current under a pressurized state, so as to weld the negative lead of the wound core (10a) to the bottom of the battery case (10c).

[0030] Preferably, the detection system includes a camera, and the camera detects the position of the center hole of the wound core,

[0031] According to the detection result of the camera, the control system controls the displacement of the welding rod along the X-axis and Y-axis on the horizontal plane through the guiding insulating sleeve (12).

[0032] Preferably, the detection system includes a photoelectric sensor (13), and the photoelectric sensor (13) is arranged on the side of the guiding insulating sleeve (12) to detect the floating state of the welding rod (7).

[0033] According to the detection result of the photoelectric sensor (13), the control system controls the displacement of the welding rod along the Z-axis in the vertical direction through the guiding insulating sleeve (12).

[0034] Preferably, the square base (121) has a base portion (121a) and two side walls (121b) extending upward from both sides of the base portion (121a), and there is a notch (121c) between the two side walls (121b).

[0035] The photoelectric sensor (13) is arranged between the two side walls (121b) and at a position flush with the upper edge of the base portion (121a), and the light beam emitted by the photoelectric sensor (13) can pass through the notch (121c).

[0036] Preferably, when the monitoring result of the photoelectric sensor is "no abnormal floating of the welding rod is detected", the control system controls the welding rod to continue to move downward along the Z-axis until the electrode of the welding rod is completely inserted into the central hole of the wound battery cell and reaches the bottom of the battery case; when the monitoring result of the photoelectric sensor is "abnormal floating of the welding rod is detected", the control system stops the downward movement of the welding rod along the Z-axis and aborts the welding operation.

[0037] Advantages of the Invention

[0038] Due to the adoption of the guiding insulating sleeve with a new structure, the spot welder of the present invention can accurately position the mounting seat of the welding rod through the square base and the sleeve when welding the bottom of the cylindrical battery, and can perform central correction of the insertion angle of the electrode of the welding rod and insulation protection through the central correction guiding hole, thereby effectively suppressing the shaking and inclination of the welding rod, avoiding external short-circuit shunting during welding, and greatly improving the welding quality and production stability of the battery. Description of the Drawings

[0039] Figure 1 A schematic structural view showing an example of the guiding insulating sleeve of the present invention, (a) a perspective view; (b) a sectional view.

[0040] Figure 2Schematic diagram showing the usage state of the guiding insulating sleeve of the present invention; (a) Initial state before the welding rod is inserted into the battery cell; (b) Final state after the welding rod is inserted into the battery cell; (c) Welding state.

[0041] Figure 3 Schematic diagram showing the three-dimensional structure of the spot welder of the present invention.

[0042] Figure 4 Schematic diagram showing the state of the spot welder of the present invention in its initial state.

[0043] Figure 5 Schematic diagram showing the state of the spot welder of the present invention in its welding state.

[0044] Figure 6 Schematic diagram showing the working process of the spot welder of the present invention.

[0045] Figure 7 Schematic diagram showing the three-dimensional structure of the welding rod.

[0046] Figure 8 Top view of the cylindrical battery.

[0047] Figure 9 Schematic diagram showing the structure of the spot welder of the prior art.

[0048] Figure 10 Schematic diagram showing the structure of the guiding sleeve of the prior art, (a) Three-dimensional view; (b) Cross-sectional view.

[0049] Figure 11 Schematic diagram showing the usage state of the guiding sleeve of the prior art; (a) Initial state before the welding rod is inserted into the battery cell; (b) Final state after the welding rod is inserted into the battery cell; (c) Welding state.

[0050] Figure 12 Schematic diagram showing the improvement effect of the current distribution during the bottom welding of the battery using the spot welder of the present invention, (a) Distribution diagram of the current value before improvement; (b) Distribution diagram of the current value after improvement. Detailed implementation mode

[0051] The spot welder equipped with a guiding sleeve is widely used in the bottom welding of cylindrical batteries. The guiding sleeve is usually installed on the electrode arm, and the cavity inside it has a clearance sliding fit structure with the mounting seat of the welding rod. Through precise aperture design, it can ensure that the welding rod always moves in a straight line during the up and down movement (i.e., the Z-axis), avoiding position deviation. In addition, during the welding process, the guiding sleeve can finely adjust the horizontal position (i.e., the X-axis and Y-axis) of the welding rod to ensure that the electrode head is aligned with the welding point. Therefore, the guiding sleeve used in the spot welder is a key component to improve the welding quality and the battery production efficiency.

[0052] The guiding insulating sleeve of the present invention is a guiding sleeve that can more accurately guide and insulate the welding rod in the spot welder. Below, with reference to the accompanying drawings, the specific embodiments of the guiding insulating sleeve of the present invention and the spot welder using the same will be described.

[0053] Figure 1 The structural schematic diagram showing an example of the guiding insulating sleeve of the present invention, (a) perspective view; (b) cross-sectional view.

[0054] As Figure 1 shown, the guiding insulating sleeve (12) successively includes a square base (121), a sleeve (122), and a center alignment guiding hole (123) from top to bottom. The interior of the square base (121) and the sleeve (122) has a cavity (12a), which can form a clearance sliding fit structure with the mounting seat (7a) of the welding rod (7). The center alignment guiding hole (123) is extendably provided on the lower surface of the sleeve (122), is a hollow tubular shape, and has a hole (12b) inside. The electrode (7b) of the welding rod (7) can be inserted into the hole (12b).

[0055] The circumferential surface of the above-mentioned cavity (12a) constitutes the positioning and guiding surface of the mounting seat (7a) of the welding rod, and the two are in a clearance fit manner, which can ensure that the welding rod can slide up and down freely in the cavity and be accurately positioned and guided. As an example, when the outer diameter Φ 安装座 of the mounting seat is 18 mm, the diameter Φ 空腔 of the cavity can be set to have a difference from the outer diameter Φ 安装座 of the mounting seat in the range of 0.02 - 0.08 mm, preferably in the range of 0.03 mm - 0.05 mm, to achieve a good clearance fit.

[0056] In the present invention, the outer part of the sleeve (122) can be cylindrical or other shapes, and its interior is part of the cavity (12a). The lower surface of the sleeve (122) is extendably provided with a hollow tubular center alignment guiding hole (123) downward, and the electrode (7b) can be inserted into the hole (12b) inside it. Therefore, the positioning and guiding effect on the welding rod can be further improved. The center alignment guiding hole and the electrode of the welding rod are also preferably in a clearance fit manner. As an example, when the outer diameter Φ 电极 of the electrode of the welding rod is 3.0 mm, the diameter Φ 空孔 of the hole (12b) of the center alignment guiding hole (123) can be set to have a difference from the outer diameter Φ 电极 of the electrode (7b), that is, Φ 空孔 -Φ 电极 in the range of 0.02 - 0.10 mm, preferably in the range of 0.05 - 0.1 mm, and most preferably 0.05 mm.

[0057] Since the guiding insulating sleeve (12) of the present invention has, in addition to the square base (121) and the sleeve (122), a central alignment guiding hole (123) located below, it is possible to ensure that the electrode of the welding rod is always in a vertical state when inserted, making the relative position between the welding rod and the negative lead at the bottom of the battery more accurate and the contact reliable, achieving a stable welding effect.

[0058] Figure 2 It is a schematic diagram of the usage state of the guiding insulating sleeve of the present invention; (a) represents the initial state before the welding rod is inserted into the battery cell; (b) represents the final state after the welding rod is inserted into the battery cell; (c) represents the welding state. For the sake of convenient display, Figure 2 the illustrations of the battery (10) are omitted in (a) and (b) of

[0059] As Figure 2 shown in (a), in the initial state before the welding rod is inserted into the battery cell, the mounting seat (7a) of the welding rod (7) is completely accommodated in the cavity (12a) of the guiding insulating sleeve (12). Therefore, stable and reliable positioning and guiding can be obtained, while the electrode (7b) of the welding rod (7) passes through the central alignment guiding hole (123) located below the guiding insulating sleeve (12), and its insertion angle can be accurately centered and corrected.

[0060] Furthermore, in the guiding insulating sleeve (12) of the present invention, in order to ensure that there is also a sufficient positioning surface for the welding rod (7) in the welding state, the two sides of the base portion (121a) of the square base (121) are heightened to form side walls (121b) extending upward. Therefore, as Figure 2 shown in (b), in the final state after the welding rod is inserted into the battery cell, the surface of the mounting seat (7a) is flush with the upper surface of the square base (121). At this time, the positioning area of the cavity (6a) of the guiding insulating sleeve (12) for the mounting seat (7a) of the welding rod (7) remains unchanged. Therefore, the welding rod (7) can still obtain stable and reliable positioning and guiding.

[0061] Since in both the initial state before inserting into the battery cell and the final state after inserting into the battery cell, the mounting seat (7a) of the welding rod (7) is completely accommodated in the cavity (6a) inside the guiding insulating sleeve (12), it is possible to ensure that positioning failure will not occur due to local dimensional changes of the welding rod (7) or the guiding insulating sleeve (12).

[0062] The central alignment guiding hole (123) located below the guiding insulating sleeve (12) is preferably formed of an insulating material. At this time, as Figure 2 shown in (c), in the welding state, the central alignment guiding hole (123) can prevent the positive lead (11) of the wound battery cell (10a) from contacting the electrode (7b) of the welding rod (7), playing a good insulating role.

[0063] Furthermore, in order to prevent the inner bending angle of the positive current collector in the battery cell from being too large and to prevent the electrode of the welding rod from contacting the cell lead (such as the positive lead), as Figure 1 (b) shows, it is preferred that a guiding conical surface (123a) inclined inward is formed at the lower end of the central alignment guiding hole (123). In order to achieve a good guiding effect, the guiding angle (the angle formed with the vertical line) can be 4 to 15°, preferably 5 to 10°, and most preferably 5°.

[0064] By designing the guiding conical surface (123a) at the lower end of the central alignment guiding hole (123), when the inner bending angle of the positive current collector above the wound battery cell (10a) fluctuates and the positive lead (11) inclines inward, it is possible to effectively suppress the external short-circuit shunt phenomenon caused by the accidental contact between the positive lead (11) and the metal electrode (7b) of the welding rod (7), or to prevent the cell lead from being crushed.

[0065] Figure 3 is a schematic perspective view of the spot welder of the present invention. The spot welder of the present invention is preferably used for bottom welding of a cylindrical battery, and the cylindrical battery includes a wound battery cell (10a) and a battery case (10c) with one end open. The spot welder of the present invention is characterized by including the above-mentioned guiding insulating sleeve.

[0066] As Figure 3 shown, the spot welder (1) of the present invention at least includes an upper electrode (4), a lower electrode (5), a welding rod (7), a pressure head (9), a detection system and a control device (not shown), and the above-mentioned guiding insulating sleeve (12). At this time, the welding rod (7) is inserted into the guiding insulating sleeve (12), and the square base (121) or the sleeve (122) of the guiding insulating sleeve (12) is connected to the control device through an electrode arm.

[0067] The detection system is used to detect the position of the central hole (10b) of the wound battery cell (10a) of the battery (10) to be welded and the position where the welding rod (7) is located; the control device controls the displacement of the welding rod (7) through the guiding insulating sleeve (12) according to the detection result of the detection system, so as to insert the electrode (7b) of the welding rod (7) into the central hole (10b) of the wound battery cell (10a).

[0068] When the electrode (7b) of the welding rod (7) reaches the bottom of the battery case (10c) of the battery (10), the pressure head (9) drives the upper electrode (4) to move downward, and conducts electricity with the lower electrode (5) through the welding rod (7), and applies a welding current under a pressurized state, so as to weld the negative lead of the wound battery cell (10a) to the bottom of the battery case (10c).

[0069] Preferably, a camera (not shown) is included in the detection system of the present invention. The camera detects the position of the central hole of the wound battery cell. Furthermore, the control system controls the displacement of the welding rod in the X-axis and Y-axis directions on the horizontal plane through the guiding insulating sleeve (12) according to the detection result of the camera.

[0070] That is to say, before welding, the camera respectively detects and locates the position of the central hole (10b) of the battery (10) to be welded and the electrode (7b) of the welding rod (7). The control system (not shown) adjusts the position of the square base (121) of the guiding insulating sleeve (12) in the horizontal direction through the electrode arm according to the detection result of the camera, so as to control the displacement of the welding rod (7) in the X-axis and Y-axis directions. More specifically, the control system compares the actual position of the electrode (7b) collected with the initial position (i.e., directly above the central hole (10b)), calculates the position deviation, and performs fine adjustment of the electrode position according to the magnitude and direction of the deviation, so that the electrode (7b) quickly and stably reaches the initial position. After the electrode (7b) reaches the initial position, the control system moves the guiding insulating sleeve (12) vertically downward, thereby controlling the displacement of the welding rod (7) in the Z-axis direction and finally reaching the target position in the welding state.

[0071] Figure 4 It is a state schematic diagram showing the initial state of the spot welder of the present invention before startup. Figure 5 It is a state schematic diagram showing the welding state of the spot welder of the present invention.

[0072] As described above, before starting up, the spot welder (1) of the present invention needs to initialize the position of the welding rod (7) to ensure that the end of the electrode (7b) of the welding rod (7) is located at a preset initial position, that is, directly above the central hole (10b) of the wound battery cell (10a) of the battery (10).

[0073] During the process of inserting the electrode (7b) into the central hole (10b), if there are foreign objects or protrusions remaining inside the central hole (10b), or the insertion angle of the electrode (7b) is not vertical enough, the electrode (7b) will be blocked and cannot be inserted smoothly, resulting in the mounting seat (7a) of the welding rod (7) floating upward relative to the guiding insulating sleeve (12), and this phenomenon is called "abnormal floating".

[0074] In the bottom welding of the battery, the monitoring of the abnormal floating of the welding rod is an important link to ensure the welding quality and stability. In the conventional spot welder, the abnormal floating of the welding rod (7) mainly depends on the abnormal response value of the pressure sensor for monitoring. However, the problem is that the pressure sensor often cannot detect the abnormality in time and give feedback, resulting in damage to the inner peripheral surface of the wound battery cell (10a) during the process of inserting the electrode (7b) into the central hole (10b).

[0075] In the present invention, it is preferable to include a photoelectric sensor (13) in the detection system. The photoelectric sensor (13) is disposed on the side surface of the guiding insulating sleeve (12) to detect the abnormal floating state of the welding rod (7). Furthermore, the control system controls the displacement of the welding rod in the Z-axis direction in the vertical direction through the guiding insulating sleeve (12) according to the detection result of the photoelectric sensor (13).

[0076] By installing the photoelectric sensor (13), the actual position of the welding rod (7) can be monitored in real time, and the data is transmitted to the control system to timely determine whether the welding rod has an abnormal floating phenomenon. When the monitoring result of the photoelectric sensor is "no abnormal floating of the welding rod is detected" (OK), the control system controls the welding rod to continue moving downward along the Z-axis until the electrode of the welding rod is completely inserted into the central hole of the wound battery cell and reaches the bottom (lower limit position) of the battery case; when the monitoring result of the photoelectric sensor is "abnormal floating of the welding rod is detected" (NG), the control system stops the downward movement of the welding rod along the Z-axis and aborts the welding operation. In this way, damage to the separator or the active material layer of the wound battery cell (10a) caused by improper insertion of the welding rod can be effectively avoided.

[0077] To detect the abnormal floating of the welding rod (7), the photoelectric sensor (13) needs to be disposed at a position flush with the upper edge of the mounting seat (7a) of the welding rod (7) in the initial state. In this way, if the mounting seat (7a) has an abnormal floating, the light beam emitted from the photoelectric sensor (13) will be blocked immediately, thereby generating a detection signal.

[0078] In the guiding insulating sleeve (12) of the present invention, in order to ensure that there is a sufficient positioning surface for the welding rod (7) in the welding state, both sides of the base portion (121a) of the square base (121) are heightened to form side walls (121b) extending upward. Depending on the specific situation, the height H of the side walls 2 can be 10 to 30 mm, preferably 15 to 25 mm, and more preferably 16 to 23 mm. As a specific example, the height H of the side walls 2 is, for example, 22 mm.

[0079] In this case, in order to promptly detect the abnormal floating of the welding rod (7) during the insertion process, the photoelectric sensor (13) needs to be set between the two side walls (121b) and flush with the upper edge of the base portion (121a). In this way, the notch (121c) formed between the two side walls (121b) can serve as a photoelectric detection notch, allowing the light beam emitted from the photoelectric sensor (13) to pass through the notch (121c). As a specific example, the photoelectric sensor (13) is set at the notch (121c), approximately 30 mm away from the bottom of the square base (121).

[0080] By arranging the photoelectric sensor (13) on the side of the guiding insulating sleeve (12), the present invention can promptly detect the abnormal floating of the welding rod (7), avoiding potential damage to the battery separator or the active material layer caused by improper insertion of the electrode (7b).

[0081] In addition, when the guiding insulating sleeve (12) drives the welding rod (7) to reach the preset lower limit position, that is, the position where the electrode (7b) just abuts against the bottom of the battery case and stops descending, the detection of the photoelectric sensor (13) can be temporarily stopped. Subsequently, the guiding insulating sleeve (12) together with the photoelectric sensor (13) continues to descend a certain distance until the mounting seat (7a) of the welding rod (7) exposes from the upper edge of the square base (121) of the guiding insulating sleeve (12).

[0082] Then, as Figure 5 shown, the spot welder (1) of the present invention enters the welding state. At this time, the pressure head (9) presses the upper electrode (4) downward under the control of the motion servo system, enabling the upper electrode (4) to conduct through the welding rod (7) with the lower electrode (5), thereby performing welding under pressure.

[0083] During the welding state, since the guiding insulating sleeve (12) of the present invention has a central alignment guiding hole (123) and is designed with a guiding conical surface (123a) at the lower end, even if the inner bending angle of the positive current collector of the wound type battery cell (10a) fluctuates and the positive lead (11) inclines inward, it can effectively suppress the external short circuit shunt phenomenon caused by accidental contact between the positive lead (11) and the metal electrode (7b) of the welding rod (7), or prevent damage to the battery cell lead.

[0084] As long as the above welding process can be smoothly implemented, there are no special regulations on the dimensions of the guiding insulating sleeve (12) used in the spot welder (1) of the present invention, but it is preferably designed to meet certain requirements.

[0085] Specifically, as Figure 1 (b) and Figure 7 shown, when the height of the base portion (121a) of the square base (121) is set as H 0, the height of the sleeve (122) is H 1 , the height of the side wall (121b) of the square base (121) is H 2 , the height of the mounting seat (7a) of the welding rod (7) is H 3 When, it is preferably satisfied that H 3 ≥H 0 +H 1 , more preferably satisfied that H 0 +H 1 +H 2 ≥H 3 ≥H 0 +H 1 , in this way, it can be ensured that the upper surface of the mounting seat (7a) is exposed from the notch (121c) of the square base (121), ensuring that the photoelectric sensor (13) can detect the abnormal floating of the welding rod (7) in time. From the perspective of further improving the detection sensitivity and reducing the interference of the deviation of the installation position of the photoelectric sensor (13) on the measurement result, it is particularly preferably satisfied that H 3 =H 0 +H 1 .

[0086] In addition, as Figure 1 (b), Figure 2 (c) and Figure 7 shown, when the height of the side wall (121b) of the square base (121) is set to H 2 , the length of the electrode (7b) of the welding rod (7) is L 3 , the height of the battery (10) is L 2 , the extension length of the center alignment guide hole (123) of the guide insulating sleeve (12) is L 1 When, it is preferably satisfied that L 1 <L 3 -L 2 -H 2 . In this way, it can be ensured that there is a certain gap, preferably more than 2 mm, between the lowermost end of the center alignment guide hole (123) and the battery (10), that is, L 3 -L 2 -H 2 -L 1 ≥2 mm, to ensure that the center alignment guide hole (123) does not directly contact the wound type battery cell (10a) and damage the positive current collector.

[0087] The extension length L 1 of the center alignment guide hole (123) mainly depends on the length of the exposed part of the electrode (7b) after the welding rod (7) is completely inserted into the battery cell (10a). In order to fully exert the center alignment and guiding function of the center alignment guide hole (123) on the electrode (7b), the extension length L1 Preferably 10 mm to 60 mm, more preferably 12 mm to 58 mm, and still more preferably 14 mm to 30 mm. As a specific example, the extension length L of the center alignment guide hole (123) 1 can be 10 to 20 mm.

[0088] To ensure safety, the center alignment guide hole (123) is preferably formed of an insulating material such as urea resin. The square base (121), the sleeve (122) and the center alignment guide hole (123) in the guide insulating sleeve (12) can be integrally formed or separately formed. The guide insulating sleeve (12) is preferably integrally formed of an insulating material.

[0089] The welding rod (7) used in the spot welder of the present invention is as Figure 7 shown. One end is a cylindrical mounting seat (7a), and the other end is a rod-shaped electrode (7b). The welding rod can be of an integral structure or a split structure. In the case of a split structure, the rod-shaped electrode (7b) is usually made of a chromium copper alloy material, and the cylindrical mounting seat (7a) is made of a copper material. The rod-shaped electrode (7b) can be replaced at any time according to the usage conditions through a locking block provided on the mounting seat.

[0090] In the present invention, the battery (10) to be welded is as Figure 8 shown. It has a battery case (10c) with one end open and a wound-type battery cell (10a) accommodated therein. The wound-type battery cell (10a) has a center hole (10b) at the axial center. Among them, the wound-type battery cell (10a) is formed by winding a positive current collector and a negative current collector each coated with an active material layer with a separator sandwiched therebetween. The positive current collector has a positive lead (11) on the upper open side, and the negative current collector has a negative lead (not shown) on the bottom side.

[0091] Figure 6 is a schematic diagram of the working process of the spot welder of the present invention.

[0092] First, use a camera to confirm the position of the center hole of the battery cell before welding. The spot welder moves the transplant X-axis and Y-axis to the position of the center hole of the battery cell (the initial position of the welding rod) according to the position data of the camera. Then, the welding rod moves along the Z-axis to perform an insertion action. When the welding rod floats up due to resistance when inserted into the battery cell hole (NG), the spot welder terminates the welding action and issues a stop alarm; when it is detected as normal insertion (OK), the upper and lower electrodes of the spot welder contact and perform a pressurizing action. When the pressure sensor reaches the set value, the spot welder performs discharging. After discharging is completed, the upper and lower electrodes return to their original positions, the welding rod is pulled out, and the transplant axis returns to the origin, waiting for the next action.

[0093] The spot welder of the present invention has achieved good results in the actual welding of the battery bottom by adopting a guiding insulating sleeve (12) with a new structure.

[0094] In the case of using the existing guiding sleeve, since the mounting seat of the welding rod is lifted and exposed during welding, the positioning surface is reduced, and the welding rod will have an inclination swing of about 0.55 mm. Therefore, in the actual welding of the battery bottom, about 10 - 20 out of 1000 batteries manufactured will have the situation of low current alarm.

[0095] In contrast, the guiding insulating sleeve of the present invention can ensure reliable positioning of the welding rod and stable center position of the electrode through the heightening design of the guiding insulating sleeve and the downward extension design of the center correction guiding hole.

[0096] To verify the above effects, actual tests of battery bottom welding were carried out on two groups of 32 batteries each in the constant voltage mode. The experimental data are shown in Table 1 and Figure 12 as follows. Among them, "before improvement" refers to the situation of battery bottom welding using a spot welder with the existing guiding sleeve, and "after improvement" refers to the situation of battery bottom welding using a spot welder with the guiding insulating sleeve of the present invention. In addition, Figure 12 is a schematic diagram of the improvement effect of the current distribution when using the spot welder of the present invention for battery bottom welding. (a) The current value distribution diagram before improvement; (b) The current value distribution diagram after improvement.

[0097] Table 1

[0098] Test Results Before Improvement After Improvement Number of Batteries n (pcs) 32 32 Average Current Value (kA) 1.23 1.17 Standard Deviation 0.107 0.035 Maximum Current Value (kA) 1.410 1.230 Minimum Current Value (kA) 0.940 1.110 Process Capability Ppk 0.68 2.08

[0099] From Table 1 and Figure 12 it can be seen that by adopting the guiding insulating sleeve of the present invention, compared with the existing guiding sleeve, the standard deviation of the welding current during welding of the spot welder is reduced by more than 3 times, indicating that the up and down fluctuation of the welding current tends to be stable, effectively solving the occurrence of low current bad alarm during welding and greatly improving the engineering ability.

[0100] The above has described the specific embodiments of the guiding insulating sleeve and the spot welder of the present invention in conjunction with the drawings. However, the present invention is not limited to the above specific embodiments, and various deformations, element combinations and changes can be made within the scope not departing from the gist of the present invention, and these deformations, element combinations and changes are also included in the protection scope of the present invention.

[0101] Symbol Explanation

[0102] 1 Spot welder

[0103] 2 Frame

[0104] 3 Electrode arm

[0105] 4 Upper electrode

[0106] 5 Lower electrode

[0107] 6 Guide sleeve

[0108] 61 Square base

[0109] 62 Sleeve

[0110] 6a Cavity

[0111] 7 Welding rod

[0112] 7a Mounting base

[0113] 7b Electrode

[0114] 8 Pressure sensor

[0115] 9 Pressing head

[0116] 10 Battery

[0117] 10a Wound cell

[0118] 10b Central hole

[0119] 10c Battery case

[0120] 11 Positive lead

[0121] 12 Guide insulating sleeve

[0122] 121 Square base

[0123] 121a Base bottom

[0124] 121b Side wall

[0125] 121c Notch

[0126] 122 Sleeve

[0127] 123 Central alignment guide hole

[0128] 123a Guide conical surface

[0129] 12a Cavity

[0130] 12b Empty hole

[0131] 13 Photoelectric sensor

Claims

1. A guide insulating sleeve (12) for guiding and insulating a welding rod (7) of a spot welding machine (1), characterized in that: From top to bottom, it is provided with a square base (121), a sleeve (122) and a center correction guide hole (123). The square base (121) and the sleeve (122) have a cavity (12a) inside, which can form a clearance sliding matching structure with the mounting seat (7a) of the welding rod (7). The center correction guide hole (123) is extendedly arranged on the lower surface of the sleeve (122), is in the shape of a hollow tube, and has an empty hole (12b) inside. The electrode (7b) of the welding rod (7) can be inserted into the empty hole (12b).

2. The guide insulating sleeve according to claim 1, characterized in that: The square base (121) comprises a base portion (121a) and two side walls (121b) extending upward from both sides of the base portion (121a), and a gap (121c) is formed between the two side walls (121b).

3. The guide insulating sleeve according to claim 2, characterized in that: When the height of the base portion (121a) of the square base (121) is set to H0, the height of the sleeve (122) is set to H1, and the height of the mounting seat (7a) of the welding rod (7) is set to H3, H3=H0+H1 is satisfied.

4. The guide insulating sleeve according to claim 3, characterized in that: When the height of the side wall (121b) of the square base (121) is set to H2, the length of the electrode (7b) of the welding rod (7) is set to L3, the height of the battery (10) as the welding object is set to L2, and the extension length of the center correction guide hole (123) is set to L1, L1<L3-L2-H2 is satisfied.

5. The guide insulating sleeve according to claim 1 or 2, characterized in that: The diameter of the hollow hole (12b) of the center correction guide hole (123) is Φ 空孔 The outer diameter Φ of the electrode (7b) of the welding rod (7) is 电极 The difference is Φ 空孔 -Φ 电极 The range is 0.02 to 0.10 mm.

6. The guide insulating sleeve according to claim 1 or 2, characterized in that: The lower end of the center correction guide hole (123) is formed with a guide cone surface (123a) inclined inwardly, and its guide angle is 4 to 15 degrees.

7. The guide insulating sleeve according to claim 1 or 2, characterized in that: The center correction guide hole (123) is formed of insulating material.

8. A spot welding machine (1) for bottom welding of a battery (10), wherein the battery (10) comprises a wound-type battery cell (10a) and a battery shell (10c) with an opening at one end, characterized in that: The invention comprises at least an upper electrode (4), a lower electrode (5), a welding rod (7), a pressure head (9), a detection system, a control device, and a guide insulating sleeve (12) according to any one of claims 1 to 7. The detection system detects the position of the central hole (10b) of the wound battery core (10a) and the position of the welding rod (7); The welding rod (7) is inserted into the guide insulating sleeve (12). The guide insulating sleeve (12) is connected to the control device. The control device controls the displacement of the welding rod (7) via the guide insulating sleeve (12) according to the detection result of the detection system, so as to insert the electrode (7b) of the welding rod (7) into the central hole (10b) of the wound battery core (10a). When the electrode (7b) of the welding rod (7) reaches the bottom of the battery shell (10c), the pressurizing head (9) drives the upper electrode (4) to move downward, and conducts with the lower electrode (5) via the welding rod (7), and applies welding current under pressure, thereby welding the negative lead of the wound battery cell (10a) and the bottom of the battery shell (10c) together.

9. The spot welding machine according to claim 8, characterized in that: The detection system includes a camera, which detects the position of the central hole of the wound battery cell. The control system controls the displacement of the welding rod on the X-axis and the Y-axis on the horizontal plane via the guide insulating sleeve (12) according to the detection result of the camera.

10. The spot welding machine according to claim 8 or 9, characterized in that: The detection system comprises a photoelectric sensor (13), which is arranged on the side of the guide insulating sleeve (12) and detects the floating state of the welding rod (7). The control system controls the Z-axis displacement of the welding rod in the vertical direction via the guide insulating sleeve (12) according to the detection result of the photoelectric sensor (13).

11. The spot welding machine according to claim 10, characterized in that: The square base (121) comprises a base portion (121a) and two side walls (121b) extending upward from both sides of the base portion (121a), and a notch (121c) is formed between the two side walls (121b). The photoelectric sensor (13) is arranged between the two side walls (121b) and at a position flush with the upper edge of the base (121a), and the light beam emitted by the photoelectric sensor (13) can pass through the notch (121c).

12. The spot welding machine according to claim 10, wherein: When the monitoring result of the photoelectric sensor is "no abnormal floating of the welding rod is detected", the control system controls the welding rod to continue to move downward along the Z axis until the electrode of the welding rod is completely inserted into the center hole of the wound battery cell and reaches the bottom of the battery shell; when the monitoring result of the photoelectric sensor is "abnormal floating of the welding rod is detected", the control system stops the downward movement of the welding rod along the Z axis and terminates the welding operation.

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