Battery cell pole group cold pressing mechanism

Abstract

The invention discloses a cell pole group cold pressing mechanism which comprises a rack and two pairs of shear type pressing mechanisms which are oppositely arranged in the inner space of the rack in a spaced mode in the horizontal direction, each shear type pressing mechanism comprises two shear type pressing units which are arranged in a front-back spaced mode, and each shear type pressing unit comprises an upper arm and a lower arm which are hinged to each other; the shear type pressing unit is connected with two lead screw mechanisms which are arranged in a vertically spaced mode in the vertical direction, and the lower arm is connected with an extrusion plate assembly through a connecting assembly; the upper arm is hinged to the machine frame. Under the condition that the rotating speed of the servo motor is the same, the speed in the downward pressing process is high first and then low, the servo motor can run at the high speed all the time, and the cold pressing efficiency can be improved; due to the fact that the pressure of pole group cold pressing can be greatly increased only within 3 mm after the pole group is contacted, the power of a servo motor and the strength requirement of a lead screw are greatly reduced, a larger speed reducer does not need to be selected, and cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of cold pressing of battery cell pole groups, and in particular to a cold pressing mechanism for a battery cell pole group. Background Art

[0002] In the power battery manufacturing process, during the winding process, after the cell is wound, the electrode assembly is removed from the winding needle and, after pre-pressing, cold-pressed to finalize the electrode assembly's shape. As the size of the electrode assembly increases and the final shape of the electrode assembly after cold pressing improves, the required cold-pressing pressure increases, for example, from 7 tons to 20 tons or even higher. To maintain production efficiency, it is also necessary to minimize the auxiliary time required for the cold-pressing mechanism to rise and fall.

[0003] The cold pressing mechanism under the existing technology adopts a servo drive motor 100 to accelerate and reduce the speed, and drives the vertical screw 300 arranged vertically through the horizontal synchronous belt 200 to directly push the pressure plate to cold press the electrode group 500. The pressure detector 400 at the bottom of the vertical screw, such as Figure 1 As shown in Figure 2, this cold press drive method requires a larger motor and a higher reduction ratio as the pressure increases. Larger motors increase cost and space requirements, while larger reduction ratios increase the auxiliary time required for the cold press mechanism to rise and fall, reducing production efficiency. Therefore, it is necessary to design a cold press mechanism that maintains efficiency while allowing for a smaller motor and space requirements. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies and defects of the prior art and to provide a cold pressing mechanism for a battery cell electrode group.

[0005] The present invention is achieved through the following technical solutions:

[0006] A cold pressing mechanism for a battery cell electrode group comprises a frame and two pairs of scissor-type pressing mechanisms arranged relatively spaced apart in a horizontal direction in an internal space of the frame, wherein each group of the scissor-type pressing mechanisms comprises two scissor-type pressing units arranged spaced apart in front and back, and each of the scissor-type pressing units comprises an upper arm and a lower arm hinged to each other, the scissor-type pressing units are connected to two screw rod mechanisms arranged spaced apart in a vertical direction, the lower arms are connected to an extrusion plate assembly via a connecting assembly; the upper arms are hinged to the frame.

[0007] As an embodiment, the extrusion plate assembly includes a pressing plate, a pressure sensor is arranged on the upper surface of the pressing plate, and a pad is arranged on the lower surface of the pressing plate.

[0008] As an embodiment, the connecting assembly includes two symmetrically arranged pull blocks arranged on the upper surface of the pressure plate, a pad block connected to the pull blocks, and a first connecting plate connected to the pad block; the pressure sensor is blocked on both sides by the pull blocks, the pad block is above the pressure sensor, the pad block is on the bottom surface of the first connecting plate, and the first connecting plate is connected to the lower arm through a first axis.

[0009] As an embodiment, the outer wall surface of the pad block has a limiting groove, the upper part of the pull block has an inner convex edge that protrudes horizontally inward and engages with the limiting groove, and the lower part of the pull block has an outer convex edge that protrudes horizontally for connecting with the pressure plate.

[0010] As an embodiment, the lower arms of the two scissor-type pressing units of each group of the scissor-type pressing mechanism are hingedly connected by a first axis, and the two first axes respectively pass through the front and rear through holes of the first connecting plate and are connected to the first connecting plate, and the two ends of the first connecting plate are respectively located between the front and rear lower arms of the two scissor-type pressing units of each group of the scissor-type pressing mechanism.

[0011] As an embodiment, the upper arm is connected to the upper part of the frame through a second shaft; there are two second shafts, which are arranged and installed on the upper part of the frame in a horizontal direction, and each second shaft is connected to the rotation of the upper arms of the two scissor-type downward pressure units.

[0012] As an embodiment, the upper arm and the lower arm of the two scissor-type downward pressure units of each group of the scissor-type downward pressure mechanism are hingedly connected by a third axis, and the two connecting blocks connecting the screw nuts of the two screw mechanisms are correspondingly connected to the two third axes, and the third axis passes through the connecting block and passes between the two screws.

[0013] As an embodiment, a second connecting plate is arranged on the outer side of the lower arm of the two scissor-type pressing units of each group of the scissor-type pressing mechanism, the second connecting plate is connected to the first axis, and the two ends of the second connecting plate have a bending portion formed by vertically bending outward, and a first slider mounting block is installed on the bending portion, and the first slider mounting block cooperates with the linear guide rail arranged vertically on the frame.

[0014] As an embodiment, a second slider mounting block is provided on the front and rear side walls of the pressure plate, and the second slider mounting block cooperates with the linear guide rail.

[0015] As an embodiment, the screw mechanism is transmission-connected to the drive shaft of the drive motor via a gear set.

[0016] The battery cell pole group cold pressing mechanism of the present invention adopts two pairs of symmetrical scissor-type pressing mechanisms. The servo motor drives two pairs of screw mechanisms to drive the scissor-type mechanisms to press downward. Under the condition that the servo motor rotates at the same speed, the speed is first fast and then slow during the pressing process. There is no need to use a larger reducer, and the servo motor can always run at high speed, which can improve the cold pressing efficiency. Moreover, since the pressure of the pole group will only increase significantly within 3 mm after contacting the pole group, the use of the scissor-type mechanism can greatly reduce the power requirements of the servo motor and the strength requirements of the screw, and a smaller motor and screw can be selected to reduce costs.

[0017] In addition, the cell pole group cold pressing mechanism of the present invention has an extrusion plate assembly that ensures that the pressing plate does not move left and right and that the pressing plate presses down the cell pole group smoothly by using the cooperation of the slide rail and the slider. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the electrode group cold pressing mechanism under the existing technology.

[0019] Figure 2 Schematic diagram of force transmission of the shear-type pressing mechanism of the battery cell electrode group cold pressing mechanism of the present invention.

[0020] Figure 3 It is a partial cross-sectional schematic diagram from the main view of the cold pressing mechanism of the battery cell electrode group of the present invention.

[0021] Figure 4 It is a three-dimensional schematic diagram of the cold pressing mechanism of the battery cell electrode group of the present invention.

[0022] Figure 5 yes Figure 3 A partially enlarged schematic diagram of part I.

[0023] Figure 6 It is a schematic diagram of the cold pressing mechanism of the battery cell electrode group of the present invention before pressing the electrode group during the pressing operation.

[0024] Figure 7 It is a schematic diagram of the battery cell electrode group cold pressing mechanism of the present invention after the electrode group is pressed during the pressing operation. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] In the actual production process of cold pressing of battery cell stage groups, the applicant found that in the cold pressing process of the battery cell pole group, the actual force is only applied within a few millimeters of pressing the battery cell pole group, and the force on the cold pressing plate gradually increases to 20 tons. The rest of the entire descending process is only subject to the gravity of the cold pressing plate and the mechanism.

[0027] Based on the above application findings of the cold press, the inventors of this application proposed the battery cell pole group cold pressing mechanism of this application, which uses a shearing mechanism to provide pressure. During the cold pressing process of the pole group, the pressure will gradually increase only within the last 3mm of the battery cell pole group. In the shearing pressure mechanism, the force transmission is as follows: Figure 2 As shown, the support arm of the scissor mechanism is subjected to a force F. Component F1 represents the pressure from the pole group, while component F2 represents the tension from the servo motor driving the lead screw. F2 / F1 = tga. When the pressure plate begins to descend but doesn't contact the pole group, angle a is large. Because the pole group is not compressed, F1 represents the weight of the mechanism. When the pole group is compressed, angle a decreases, and F1 represents the combination of the high pressure and the weight of the mechanism.

[0028] According to the above formula, the smaller the angle a is when the pole group is pressed, the smaller the ratio of the pulling force F2 driven by the servo motor to the pressure of the pole group will be. This can greatly reduce the force of the servo motor, and the descending speed when the pole group is not pressed is also faster, which can improve the cold pressing efficiency.

[0029] See also Figures 3 to 7 As shown, in the exemplary embodiment of the present application, the battery cell pole group cold pressing mechanism includes a frame 1 and two pairs of scissor-type pressing mechanisms arranged relatively spaced apart in the horizontal direction in the internal space of the frame, each group of the scissor-type pressing mechanisms includes two scissor-type pressing units arranged spaced apart in the front and back, each of the scissor-type pressing units includes an upper arm 3 and a lower arm 4 hinged to each other, the scissor-type pressing units are connected to two screw mechanisms arranged spaced apart in the vertical direction, the screw mechanisms move synchronously to drive the scissor-type pressing units to extend or retract, and when extended, the pole group can be pressed, the lower arm is connected to the extrusion plate assembly through a connecting assembly; the upper arm is hinged to the frame 1.

[0030] In some embodiments or implementations, the upper arm is composed of two arm plates, the lower arm is one arm plate, and the lower arm is installed by limiting the two arm plates of the upper arm on the outside.

[0031] In some embodiments, the rack 1 is a rectangular frame having a bottom plate that can support the pole group to be cold pressed. Four rectangular columns are arranged on the bottom plate. At the upper part of the rack, two adjacent columns among the four columns are connected by a connecting plate to form a rectangular frame.

[0032] As an embodiment, the extrusion plate assembly includes a pressing plate 12, a pressure sensor 11 is arranged on the upper surface of the pressing plate, and a pad 13 is arranged on the lower surface of the pressing plate. When working, the pad 13 is used to press the battery cell electrode group.

[0033] As an embodiment, the connecting assembly includes two symmetrical pulling blocks 10 arranged on the upper surface of the pressure plate, a pad 9 connected to the pulling blocks 10, and a first connecting plate 7 connected to the pad; the pressure sensor 11 is surrounded by the pulling block 10, and the pad 9 is above the pressure sensor 11. The pad 9 is installed on the bottom surface of the first connecting plate 7, and the first connecting plate 7 is connected to the lower arm; wherein, when the scissor-type pressing mechanism is raised, the pad 9 can pull up the pressure plate 12 through the pulling block 10, and when not pressed, there is no contact between the pad 9 and the pressure sensor 11. After the pole group is pressed, the pad 9 will press the pressure sensor 11 to detect the pressure; in addition, when the thickness of the battery cell pole group to be pressed changes, the pad 9 of the corresponding height can be replaced to ensure that the maximum pressure is reached at the appropriate angle.

[0034] As an embodiment, the outer wall surface of the cushion block has a limiting groove 9-1, the upper part of the pull block has an inner convex edge 10-1 formed by an inward horizontal protrusion that is engaged with the limiting groove, and the inner convex edge 10-1 is stuck in the limiting groove 9-1, and the lower part of the pull block has an outer convex edge 10-2 formed by a horizontal protrusion for connecting with the pressure plate. With the help of the outer convex edge 10-2, the two pull blocks 10 are connected to the pressure plate 12 by bolts. Specifically, each of the pull blocks 10 is a Z-shaped structure.

[0035] As an embodiment, the lower arms 4 of the two scissor-type pressing units of each group of the scissor-type pressing mechanism are each hingedly connected to a first shaft 6, and the two first shafts 6 are each connected to the first connecting plate 7 through the front and rear through holes of the first connecting plate 7, and the two ends of the first connecting plate 7 are each located between the front and rear arranged lower arms 4 of the two scissor-type pressing units of each group of the scissor-type pressing mechanism, thereby realizing the connection between the first connecting plate 7 and the lower arms through the first shaft 6.

[0036] As an embodiment, the upper arm 3 is connected to the upper part of the frame 1 through a second shaft 2; there are two second shafts 2, which are arranged and installed on the upper part of the frame 1 in a horizontally spaced manner, and each second shaft 2 is connected to the rotation of the upper arms 3 of the two scissor-type downward pressure units.

[0037] As an embodiment, the upper arm and the lower arm of the two scissor-type pressing units of each group of the scissor-type pressing mechanism are hingedly connected by a third shaft 5, and the two connecting blocks 17 connecting the screw nuts of the two screw mechanisms are correspondingly connected to the two third shafts 5. The third shaft 5 passes through the connecting block 17 and passes between the two screw rods 16. The third shaft 5 connecting block 17 and the screw rod 16 are connected, and the two screw rods 16 are symmetrically distributed on both sides of the connecting block 17 to ensure that the upper and lower forces are uniform when tightening and no rotational torque is generated.

[0038] As an embodiment, a second connecting plate 8 is arranged on the outer side of the lower arm 4 of the two scissor-type pressing units of each group of the scissor-type pressing mechanism, the second connecting plate is connected to the first axis, and the two ends of the second connecting plate have a bending portion formed by vertically bending outward, and a first slider connecting block is installed on the bending portion. The first slider connecting block is connected to the linear guide rail vertically arranged on the frame, which can ensure that the upper arm 3 and lower arm 4 symmetrical on both sides are pressed down synchronously without deviation.

[0039] As an embodiment, a second slider connecting block 15 is provided on the front and rear side walls of the pressing plate 12 , and the second slider connecting block 15 is connected to the linear guide rail 14 to ensure that the pressing plate 12 will not be unbalanced when pressed downward.

[0040] As an embodiment, the screw mechanism is connected to the drive shaft of the drive motor through a gear set. Specifically, a gear 18 is installed on one side of the screw 16, and the two gears 18 are driven to rotate simultaneously by the intermediate gear 19, and the intermediate gear 19 is connected to the servo motor 20.

[0041] In an exemplary embodiment of the present application, the pressing method of the electrode group cold pressing mechanism is as follows:

[0042] S1 is to be cold pressed. The electrode group enters the bottom of the cold press plate 13 through the conveyor belt;

[0043] S2. After the cold electrode group is detected in place, the servo motor 20 starts to rotate and drives the intermediate gear 19 to rotate. The intermediate gear 19 drives the two gears 18 to rotate, and the gear 18 drives the screw 16 to rotate;

[0044] S3. The screw 16 drives the connecting block 17 to move, and the connecting block 17 drives the upper arm 3 and the lower arm 4 to rotate through the third shaft 5;

[0045] S4. The lower arm 4 drives the first connecting plate 7 downwardly through the first shaft 6, where the speed and pressure of the downward pressure are related to the speed and torque of the servo motor and the tangent of half the angle between the upper arm 3 and the lower arm 4;

[0046] S5. The first connecting plate 7 is pressed onto the pressure sensor 11 through the cushion block 9, and the actual cold pressing pressure is detected by the pressure sensor 11.

[0047] S6. The pressure sensor 11 presses the electrode group to be cooled 21 through the pressure plate 12 and the pad 13. After the pressure sensor 11 detects that the set pressure has been reached, the servo motor 20 stops rotating. After the holding time is reached, the servo motor 20 reverses and the pressure plate is lifted.

[0048] Example:

[0049] The electrode group with a thickness of 23mm after cold pressing was selected as the electrode group to be cold pressed for the experimental sample. Figure 6 and Figure 7 After the selected electrode group 21 to be cooled enters the cold press, the servo motor 20 rotates, and through the intermediate gear 19 and gear 18, the two screws 16 rotate, driving the connecting block 17 to move toward the center. The upper arm 3 and the lower arm 4 rotate, pushing the first connecting plate 7 downward, and the pad 9 presses the pressure sensor 11, and the electrode group to be cooled is pressed through the pressure plate 12 and the pad 13. When the pressure detected by the pressure sensor reaches the set value, the servo motor stops and maintains the pressure for the set time. After the pressure is maintained, the servo motor reverses, and the pressure plate 12 and pad 13 are lifted, and the next cold press is carried out.

[0050] Table 1 shows the difference between this application and the original solution ( Figure 1 Cold pressing scheme shown), comparison of press plate speed, pressure and motor power at different heights of the press plate from the bottom surface.

[0051] It can be seen that the proposed solution has a faster speed at the beginning when the pressure before contacting the electrode group is very low. As the pressure plate descends, the speed gradually decreases while the servo motor speed remains unchanged. After the electrode group is pressed to cool, the original solution requires 4.51 kW of motor power, while the proposed solution only requires 1.08 kW. Furthermore, the speed is faster when the pressure is low and slower when the pressure is high, which better meets actual usage needs.

[0052] Table 1

[0053]

[0054] The basic principles, main features and advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0055] The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein.

[0056] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. The cold pressing mechanism of the battery cell group is characterized by: It includes a frame and two pairs of scissor-type pressing mechanisms arranged relatively and spaced apart in the horizontal direction in the internal space of the frame, each group of the scissor-type pressing mechanisms includes two scissor-type pressing units arranged spaced apart in the front and back, each of the scissor-type pressing units includes an upper arm and a lower arm hinged to each other, the scissor-type pressing units are connected to two screw rod mechanisms arranged spaced apart in the vertical direction, the lower arms are connected to the extrusion plate assembly through a connecting assembly; the upper arm is hinged to the frame.

2. The battery cell electrode group cold pressing mechanism according to claim 1, characterized in that: The extrusion plate assembly includes a pressing plate, a pressure sensor is arranged on the upper surface of the pressing plate, and a backing plate is arranged on the lower surface of the pressing plate.

3. The cold pressing mechanism for the battery cell electrode group according to claim 2, characterized in that: The connecting assembly includes two symmetrically arranged pulling blocks arranged on the upper surface of the pressure plate, a pad block connected to the pulling blocks, and a first connecting plate connected to the pad block; the pressure sensor is shielded on both sides by the pulling blocks, the pad block is above the pressure sensor, the pad block is on the bottom surface of the first connecting plate, and the first connecting plate is connected to the lower arm through a first axis.

4. The battery cell electrode group cold pressing mechanism according to claim 3, characterized in that: The outer wall surface of the cushion block has a limiting groove, the upper part of the pulling block has an inner convex edge that protrudes horizontally inward and engages with the limiting groove, and the lower part of the pulling block has an outer convex edge that protrudes horizontally for connecting with the pressing plate.

5. The battery cell electrode group cold pressing mechanism according to claim 3, characterized in that: The lower arms of the two scissor-type pressing units of each group of the scissor-type pressing mechanism are hingedly connected by a first axis, and the two first axes respectively pass through the front and rear through holes of the first connecting plate and are connected to the first connecting plate, and the two ends of the first connecting plate are respectively located between the front and rear lower arms of the two scissor-type pressing units of each group of the scissor-type pressing mechanism.

6. The battery cell electrode group cold pressing mechanism according to claim 5, characterized in that: The upper arm is connected to the upper part of the frame through a second shaft; there are two second shafts, which are arranged and installed on the upper part of the frame in a horizontal direction, and each second shaft is connected to the rotation of the upper arms of the two scissor-type downward pressure units.

7. The battery cell electrode group cold pressing mechanism according to claim 6, characterized in that: The upper arm and the lower arm of the two scissor-type pressing units of each group of the scissor-type pressing mechanism are hingedly connected by a third axis, and the two connecting blocks connecting the screw nuts of the two screw mechanisms are correspondingly connected to the two third axes, and the third axis passes through the connecting block and passes between the two screws.

8. The battery cell electrode group cold pressing mechanism according to claim 3, characterized in that: A second connecting plate is arranged on the outer side of the lower arm of the two scissor-type pressing units of each group of the scissor-type pressing mechanism, and the second connecting plate is connected to the first shaft. The two ends of the second connecting plate have a bent portion formed by vertically bending outward, and a first slider mounting block is installed on the bent portion. The first slider mounting block cooperates with the linear guide rail arranged vertically on the frame.

9. The battery cell electrode group cold pressing mechanism according to claim 8, characterized in that: A second slider mounting block is provided on the front and rear side walls of the pressing plate, and the second slider mounting block cooperates with the linear guide rail.

10. The battery cell electrode group cold pressing mechanism according to claim 1, characterized in that: The screw mechanism is connected to the drive shaft of the drive motor through a gear set.

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