Lithium battery pole piece hot-pressing device with uniform heat conduction

Abstract

The utility model discloses a lithium battery pole piece hot-pressing device with uniform heat conduction, and belongs to the technical field of battery production equipment. The lithium battery pole piece hot-pressing device with the uniform heat conduction comprises a lower hot-pressing plate and an upper hot-pressing plate, the lower hot-pressing plate and the upper hot-pressing plate are connected through a guide structure, and the upper hot-pressing plate can reciprocate along the guide structure; a groove is formed in the lower hot pressing plate, at least one group of level bubbles is arranged on two sides of the groove, the group of level bubbles comprises two level bubbles, and the two level bubbles are in central symmetry along the central point of the groove. According to the utility model, the level bubbles are symmetrically arranged on the two sides of the groove. Therefore, whether the hot pressboard is horizontal or not can be detected in real time, when the hot pressboard inclines or deforms to cause partial inclination, the level bubble can remind a worker that the hot pressboard is not horizontal any more, and the worker can adjust the hot pressboard in time conveniently.

Description

Technical Field

[0001] The utility model relates to the technical field of battery production equipment, and in particular, to a hot pressing device for lithium battery electrode sheets with uniform heat conduction. Background Art

[0002] Lithium-ion batteries have been widely used in many mobile devices in the fields of national defense, industry, and civil use due to their advantages of high energy density, small volume, long service life, and low self-discharge. The hot pressing mold is used to manufacture the battery core and is an indispensable part of the lithium-ion battery manufacturing process. Its main functions are to improve the flatness of the lithium-ion battery, make the thickness of the battery core meet the requirements and have high consistency; eliminate diaphragm wrinkles, expel the air inside the battery core, make the diaphragm and the positive and negative electrode sheets closely adhere together, shorten the lithium-ion diffusion distance, and reduce the battery internal resistance. Therefore, the main purposes of the hot pressing and shaping of the battery core include: 1. Improve the flatness of the lithium-ion battery, make the thickness of the battery core meet the requirements and have high consistency; 2. Eliminate diaphragm wrinkles, expel the air inside the battery core, make the diaphragm and the positive and negative electrode sheets closely adhere together, shorten the lithium-ion diffusion distance, and reduce the battery internal resistance.

[0003] For the existing hot pressing molds for lithium-ion batteries, generally, the heating wire is used to generate heat and the heat conducting oil is used to conduct heat to raise the temperature of the hot pressing plate, and finally, the hot pressing plate in the high-temperature state is used to extrude the stacked lithium-ion battery cores.

[0004] During the use of the existing hot pressing plates, due to the need for long-term operation, after being used for a certain period of time, the hot pressing plates often become uneven. At this time, it is not easy for the staff to find the slight inclination of the hot pressing plates, resulting in uneven heat conduction when the battery electrode sheets are hot pressed, and the heating conditions of each point of the stacked lithium-ion battery cores are different, which further affects the final quality of the hot pressing work of the stacked lithium-ion battery cores.

[0005] Furthermore, when the hot pressing plate is adjusted to be flat, due to the existence of thinning areas on some electrode sheets, the thickness distribution of the overall stacked cores is uneven, and it is often difficult for the completely horizontal hot pressing plate to evenly transfer heat to the ear side part of the stacked cores, and there will also be a problem that the heating conditions of each point of the stacked cores are different.

[0006] For example, Chinese patent document CN210837976U discloses a lithium battery hot pressing plate and a hot pressing device, belonging to the technical field of lithium battery production. The surface of the lithium battery hot pressing plate of this application in contact with the lithium battery core is provided with a Teflon electroplating layer. The hot pressing plate of this application is a device in which even if the hot pressing plate is inclined during the hot pressing process, the staff cannot find it in time. Summary of the Utility Model

[0007] 1. Technical Problems to be Solved by the Utility Model

[0008] In view of the problem that it is not easy for the staff to find that the existing hot pressing device is tilted, the utility model can prominently remind the staff whether the hot pressing plate is in a horizontal state by arranging several groups of spirit levels on the hot pressing plate.

[0009] Furthermore, in view of the situation that the existing pole piece sometimes has a thinning area, the utility model heats the pole piece with heat-conducting silica gel to ensure uniform heating of the pole piece.

[0010] 2. Technical solution

[0011] In order to achieve the above object, the technical solution provided by the utility model is as follows:

[0012] A hot pressing device for lithium battery pole pieces with uniform heat conduction of the utility model comprises a lower hot pressing plate and an upper hot pressing plate, the lower hot pressing plate and the upper hot pressing plate are connected through a guiding structure, and the upper hot pressing plate can reciprocate along the guiding structure; a groove is formed on the lower hot pressing plate, at least one group of spirit levels is arranged on both sides of the groove, and one group of spirit levels comprises two spirit levels, and the two spirit levels are centrosymmetric about the center point of the groove. With such a setting, the spirit levels are arranged on both sides of the groove and symmetrically, so as to be able to detect whether the hot pressing plate is horizontal in real time. When the hot pressing plate is tilted or deformed to cause part of it to tilt, the spirit levels can prompt the staff that the hot pressing plate is no longer horizontal, which is convenient for the staff to make timely adjustments.

[0013] As a further improvement of the utility model, when more than one group of spirit levels are arranged, the connection lines of the spirit levels on the same side of the groove form a first spirit level line, and the first spirit level line is parallel to the side of the groove. The connection lines of the spirit levels on both sides of the groove form a second spirit level line, and the second spirit level line is perpendicular to the first spirit level line. With such a setting, it can be ensured that the spirit levels are arranged circumferentially around the groove, and when there is an uneven situation in the groove, it can be displayed in time, so as to prompt the staff in time.

[0014] As a further improvement of the utility model, a convex block is arranged on the upper hot pressing plate, and the convex block corresponds to the position of the groove and has the same size. With such a setting, it is convenient to hot press the pole piece.

[0015] As a further improvement of the utility model, lower heat-conducting silica gel is arranged in the groove, upper heat-conducting silica gel is arranged on the convex block, the lower heat-conducting silica gel and the upper heat-conducting silica gel are arranged oppositely, and both the lower heat-conducting silica gel and the upper heat-conducting silica gel are elastic materials. With such a setting, when there is a thinning area on the pole piece, under the action of elastic force, the elastic heat-conducting silica gel is closely attached to the pole piece, so as to ensure uniform heating of the pole piece during hot pressing and prevent the occurrence of lithium plating.

[0016] As a further improvement of the present utility model, a lower tab shaping block is provided on the groove, an upper tab shaping block is provided on the convex block, and the upper tab shaping block and the lower tab shaping block are arranged oppositely. Such an arrangement can shape the tabs during hot pressing, facilitating subsequent encapsulation.

[0017] As a further improvement of the present utility model, the lower tab shaping block protrudes outward relative to the lower thermal conductive silicone; the upper tab shaping block protrudes outward relative to the upper thermal conductive silicone. With such an arrangement, the tabs can be welded thinner than the electrode plate, facilitating subsequent encapsulation.

[0018] As a further improvement of the present utility model, the convex block is provided on the upper pressure plate, and a pressure sensor is provided between the upper pressure plate and the convex block. Such an arrangement can detect the pressure of the hot pressing plate in real time, preventing the hot pressing plate from damaging the battery electrode plate.

[0019] As a further improvement of the present utility model, the guiding structure includes a plurality of screw rods, and the screw rods are fixed on the lower hot pressing plate; the upper hot pressing plate is sleeved on the screw rods and can move axially along the screw rods. A limiting member is provided on the screw rods, and the upper hot pressing plate is located between the limiting member and the lower hot pressing plate. Such an arrangement can limit the moving distance of the upper hot pressing plate, preventing the hot pressing plate from moving excessively and falling off.

[0020] 3. Beneficial effects

[0021] Adopting the technical solution provided by the present utility model, compared with the existing well-known technologies, it has the following remarkable effects:

[0022] A hot pressing device for lithium battery electrode plates with uniform heat conduction of the present utility model uses a spirit level to display the horizontal state of the hot pressing plate in real time. When the hot pressing plate is not horizontal, it can timely remind the staff, allowing the staff to adjust in time, reducing the impact on the battery cell electrode plates. At the same time, the elastic thermal conductive silicone is used to heat the electrode plates. When there is a thinning area on the electrode plate, the thermal conductive silicone can still be in close contact with the electrode plate, so that the thinning area of the electrode plate can also be fully hot pressed. The device of the present utility model has rapid temperature transfer, uniform hot pressing, high flatness, sufficient hot pressing in the thinning area, high consistency of the battery cell thickness, and effectively avoids the problem of lithium deposition in the thinning area of lithium-ion batteries. Brief description of the drawings

[0023] Figure 1 It is a schematic diagram of the overall structure of the hot pressing device of the present utility model;

[0024] Figure 2 It is a top view of the structure of the lower hot pressing plate in the hot pressing device of the present utility model.

[0025] Explanation of the reference numerals in the schematic diagram:

[0026] 1. Lower hot pressing plate; 11. Base; 12. Lower pressing plate; 13. Thermometer; 14. Lower heat conductive silica gel; 15. Lower tab shaping block; 16. Groove; 17. Spirit level; 171. First level line; 172. Second level line; 18. Mounting hole;

[0027] 2. Upper hot pressing plate; 21. Upper pressing plate; 22. Protrusion; 23. Upper heat conductive silica gel; 24. Upper tab shaping block; 25. Pressure sensor; 26. Fixed block; 27. Connecting rod;

[0028] 3. Guide structure; 31. Screw; 32. Limiting member. Detailed implementation manner

[0029] In order to make the above - mentioned objects, features and advantages of the utility model more obvious and understandable, the following detailed description of the specific implementation manner of the utility model will be given with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the utility model. However, the utility model can be implemented in many other ways different from those described here. Those skilled in the art can make similar improvements without departing from the connotation of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed below.

[0030] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0032] In the present utility model, unless otherwise clearly defined and limited, terms such as "installation", "connection", "linkage", "fixation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication between two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] In the present utility model, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on the top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under the bottom of" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower horizontal height than the second feature.

[0034] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0035] Embodiment

[0036] Combined Figure 1 and Figure 2 With reference to and, a hot pressing device for lithium battery electrode sheets with uniform heat conduction according to this embodiment includes a lower hot pressing plate 1 and an upper hot pressing plate 2. Among them, the lower hot pressing plate 1 and the upper hot pressing plate 2 are connected by a guiding structure 3, and the upper hot pressing plate 2 can reciprocate along the guiding structure 3. In this embodiment, the lower hot pressing plate 1 includes a base 11, and a groove 16 is formed on the base 11. The groove 16 is disposed at the middle position of the lower hot pressing plate 1, and the size of the groove 16 is the same as the size of the battery electrode sheet to be hot pressed. On the upper hot pressing plate 2, a convex block 22 is provided. The position of the convex block 22 corresponds to the position of the groove 16, and the size of the convex block 22 is the same as the size of the groove 16. When the upper hot pressing plate 2 moves downward to contact the lower hot pressing plate 1, the convex block 22 just presses into the groove 16, and hot pressing is performed on the battery electrode sheet disposed in the groove 16.

[0037] In this embodiment, at least one set of spirit levels 17 is arranged on both sides of the groove 16. One set of spirit levels 17 includes two spirit levels 17, and the two spirit levels 17 are centrosymmetric about the center point of the groove 16. Among them, when more than one set of spirit levels 17 is arranged, the connection lines of the spirit levels 17 on the same side of the groove 16 form a first level line 171, and the first level line 171 is parallel to the side of the groove 16. When an even number of sets of spirit levels 17 is arranged, the spirit levels 17 on both sides of the groove 16 are connected in pairs to form a second level line 172, and the second level line 172 is perpendicular to the first level line 171. When an odd number of sets of spirit levels 17 is arranged, the spirit levels 17 on both sides of the groove 16 are connected in pairs to form a second level line 172. One set of spirit levels 17 is located at the midpoint of the long side of the groove 16, and a second level line 172 is correspondingly formed within this set of spirit levels 17. The spirit levels 17 of other sets are connected to the spirit levels 17 of non-this set to form a second level line 172. Specifically in this embodiment, two sets of spirit levels 17 are arranged, that is, a total of four spirit levels 17 are arranged. The four spirit levels 17 are respectively arranged at the positions close to the four corners of the groove 16. The first level line 171 and the second level line 172 formed by the four spirit levels 17 form a rectangle. With such an arrangement, it can be ensured that the spirit levels 17 are arranged circumferentially around the groove 16, and when the groove 16 is uneven, it can be displayed in time, thus timely reminding the staff.

[0038] In this embodiment, a lower heat-conducting silica gel 14 is arranged in the groove 16, and at the same time, an upper heat-conducting silica gel 23 is arranged on the convex block 22. The lower heat-conducting silica gel 14 and the upper heat-conducting silica gel 23 are arranged opposite to each other, and both the lower heat-conducting silica gel 14 and the upper heat-conducting silica gel 23 are elastic materials. In this embodiment, the lower heat-conducting silica gel 14 is filled in the groove 16, and the upper heat-conducting silica gel 23 is coated on the convex block 22. When hot-pressing the pole piece, the lower heat-conducting silica gel 14 contacts the lower side of the battery pole piece; the upper heat-conducting silica gel 23 contacts the upper side of the battery pole piece. Since both the lower heat-conducting silica gel 14 and the upper heat-conducting silica gel 23 are elastic materials, when there is a thinning area on the pole piece, the elastic heat-conducting silica gel is closely attached to the pole piece under the action of elastic force, so as to ensure that the pole piece is evenly heated during hot-pressing and no lithium deposition occurs.

[0039] In this embodiment, a lower tab shaping block 15 is further disposed in the groove 16, and an upper tab shaping block 24 is disposed on the convex block 22. The upper tab shaping block 24 and the lower tab shaping block 15 are disposed opposite to each other. In this embodiment, two lower tab shaping blocks 15 are provided and are respectively disposed on two opposite sides of the groove 16; two upper tab shaping blocks 24 are also provided and are respectively disposed on two opposite sides of the convex block 22. The lower tab shaping block 15 protrudes outward relative to the lower thermal conductive silicone 14; the upper tab shaping block 24 protrudes outward relative to the upper thermal conductive silicone 23. When installing the hot pressing device, the thermal conductive silicone can be coated first and then the tab shaping block can be installed, or the tab shaping block can be installed first and then the thermal conductive silicone can be coated. With such a setting, the tab can be welded thinner than the electrode plate, which is convenient for subsequent packaging.

[0040] In this embodiment, the upper hot pressing plate 2 further includes an upper pressing plate 21. The convex block 22 is disposed on the upper pressing plate 21, and a pressure sensor 25 is disposed between the upper pressing plate 21 and the convex block 22. The pressure sensor 25 is connected to the connecting rod 27, and the connecting rod 27 is connected to the fixing block 26 disposed on the upper pressing plate 21, and the pressure sensor 25 is installed on the upper pressing plate 21. This embodiment can detect the pressure of the hot pressing plate in real time to prevent the hot pressing plate from damaging the battery electrode plate. This embodiment also disposes a thermometer 13 on the side of the groove 16 to detect the temperature of the hot pressing plate and prevent the hot pressing plate from being overheated or overcooled, resulting in over-pressing or under-pressing of the battery electrode plate.

[0041] In this embodiment, the guiding structure 3 includes a plurality of screw rods 31. The screw rods 31 are fixed to the lower hot pressing plate 1 through the mounting holes 18 formed in the base 11; the upper hot pressing plate 2 is sleeved on the screw rods 31 and can move axially along the screw rods 31. A limiting member 32 is disposed on the screw rods 31, and the upper hot pressing plate 2 is located between the limiting member 32 and the lower hot pressing plate 1. With such a setting, the moving distance of the upper hot pressing plate 2 can be limited to prevent the hot pressing plate from moving excessively and falling off.

[0042] This embodiment can automatically complete the hot pressing work of the lamination process of lithium-ion batteries, greatly reducing the labor burden of personnel. During the hot pressing process, the level bubble 17 is used to more intuitively judge the levelness of the hot pressing plate. At the same time, the rebound force of the thermal conductive silicone layer can effectively solve the gap problem between the electrode plate and the separator in the thinning area. The tab shaping block heats the laminated core tabs, enabling the overall heat of the laminated core to be evenly and quickly transmitted. The laminated core is fully heated through the heat conduction of the metal foil, ensuring the efficiency and final quality of the hot pressing work of the lamination process of lithium-ion batteries.

[0043] The above has schematically described the present utility model and its implementation manners. This description is not restrictive, and only one of the implementation manners of the present utility model is shown in the accompanying drawings. The actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the creation of the present utility model, design similar structural modes and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present utility model.

Claims

1. A lithium battery pole piece hot pressing device with uniform heat conduction, comprising a lower hot pressing plate (1) and an upper hot pressing plate (2), wherein the lower hot pressing plate (1) and the upper hot pressing plate (2) are connected via a guide structure (3), and the upper hot pressing plate (2) can reciprocate along the guide structure (3); characterized in that: A groove (16) is provided on the lower hot pressing plate (1), and at least one group of level bubbles (17) are arranged on both sides of the groove (16). The group of level bubbles (17) includes two level bubbles (17), and the two level bubbles (17) are symmetrical along the center point of the groove (16).

2. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 1, characterized in that: When more than one group of vials (17) are provided, a line connecting the vials (17) located on the same side of the groove (16) forms a first level line (171), and the first level line (171) is parallel to the side of the groove (16).

3. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 2, characterized in that: The level bubbles (17) located on both sides of the groove (16) are connected in pairs to form a second level line (172), and the second level line (172) is perpendicular to the first level line (171).

4. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 1, characterized in that: A bulge (22) is provided on the upper hot pressing plate (2), and the bulge (22) corresponds to the position of the groove (16) and has the same size.

5. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 4, characterized in that: A lower thermally conductive silicone rubber (14) is arranged in the groove (16), and an upper thermally conductive silicone rubber (23) is arranged on the protrusion (22). The lower thermally conductive silicone rubber (14) and the upper thermally conductive silicone rubber (23) are arranged opposite to each other, and both the lower thermally conductive silicone rubber (14) and the upper thermally conductive silicone rubber (23) are made of elastic materials.

6. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 5, characterized in that: A lower pole lug shaping block (15) is arranged on the groove (16), and an upper pole lug shaping block (24) is arranged on the protrusion (22), and the upper pole lug shaping block (24) and the lower pole lug shaping block (15) are arranged opposite to each other.

7. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 6, characterized in that: The lower pole ear shaping block (15) protrudes outward relative to the lower heat-conducting silicone rubber (14); and the upper pole ear shaping block (24) protrudes outward relative to the upper heat-conducting silicone rubber (23).

8. The lithium battery pole piece hot pressing device with uniform heat conduction according to claim 4, characterized in that: The convex block (22) is arranged on the upper pressing plate (21), and a pressure sensor (25) is arranged between the upper pressing plate (21) and the convex block (22).

9. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 8, characterized in that: The guide structure (3) comprises a plurality of screw rods (31), wherein the screw rods (31) are fixed on the lower hot pressing plate (1); the upper hot pressing plate (2) is sleeved on the screw rods (31) and can move axially along the screw rods (31).

10. A lithium battery pole piece hot pressing device with uniform heat conduction according to claim 9, characterized in that: A limiting member (32) is provided on the screw rod (31), and the upper hot pressing plate (2) is located between the limiting member (32) and the lower hot pressing plate (1).

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