Hot pressing mechanism and battery cell winding equipment

Abstract

The utility model relates to the technical field of battery cell production, and provides a hot pressing mechanism and battery cell winding equipment. Wherein the hot-pressing mechanism comprises a first hot-pressing roller and a roller set, the roller set comprises at least two second hot-pressing rollers which are arranged at intervals in the circumferential direction of the first hot-pressing roller, the second hot-pressing rollers and the first hot-pressing roller are arranged at intervals so as to form an extrusion gap for a laminated material belt to pass through, and the second hot-pressing rollers and the first hot-pressing roller are both used for heating the laminated material belt; and the stacked material belt is jointly extruded. According to the hot-pressing mechanism, the stacked material belt can be continuously hot-pressed for at least two times, and the compaction degree of the stacked material belt can be improved. Besides, all the second hot-pressing rollers are arranged at intervals along the circumferential direction of the first hot-pressing roller, so that the laminated material belt is hot-pressed in a bent form in the hot-pressing mechanism, the whole laminated material belt is uniformly stressed, and the risks of wrinkling and breaking when the laminated material belt is used for forming the battery cell are further reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of battery core production, in particular to a hot pressing mechanism and battery core winding equipment. Background Art

[0002] When producing wound batteries, a hot pressing mechanism is required to hot press the stacked positive electrode sheets, separators and negative electrode sheets to press them together, and then a winding mechanism is used to wind the pressed materials to form the battery cells. In the prior art, the hot pressing mechanism includes two hot pressing rollers arranged opposite to each other, and the two hot pressing rollers are arranged at intervals for the stacked materials to pass through. Under the pressure of the two hot pressing rollers, the stacked materials are pressed together. However, the pressing quality of the existing hot pressing mechanism is low, and there is still a certain gap between the various materials after pressing, resulting in loose contact between the positive electrode sheet and the negative electrode sheet. In this way, not only will the detection rate of the battery cell hipot test be reduced, but also the cycle performance of the battery using these batteries will be reduced. Utility Model Content

[0003] The utility model aims to provide a hot pressing mechanism and a battery core winding device, aiming to solve the technical problem of low pressing quality of the existing hot pressing mechanism.

[0004] In the first aspect, the present application provides a hot pressing mechanism, which includes a first hot pressing roller and a roller group, the roller group includes at least two second hot pressing rollers arranged at intervals along the circumference of the first hot pressing roller, each second hot pressing roller is arranged at intervals from the first hot pressing roller to form an extrusion gap for a stacked material strip to pass through, wherein each second hot pressing roller and the first hot pressing roller are used to heat the stacked material strip and jointly extrude the stacked material strip.

[0005] The beneficial effect of the hot pressing mechanism provided by the utility model is that after the laminated material strip enters the extrusion gap between the first hot pressing roller and the second hot pressing roller, it is pressed together by the two under high temperature. The existing hot pressing mechanism has only two hot pressing rollers arranged opposite to each other. Compared with them, firstly, the hot pressing mechanism has at least two second hot pressing rollers, that is, the hot pressing mechanism can continuously hot press the laminated material strip at least twice, which is beneficial to improve the compaction degree of the laminated material strip. Secondly, since all the second hot pressing rollers are arranged at intervals along the circumference of the first hot pressing roller, the laminated material strip is hot pressed in a curved form in the hot pressing mechanism, so that the overall force of the laminated material strip is uniform, thereby reducing the risk of wrinkling and breaking when the laminated material strip is formed into a battery cell. In this way, the pressing quality of the laminated material strip by the hot pressing mechanism is greatly improved, which is beneficial to improve the detection rate of the subsequently formed battery cells in the hipot test, and improve the cycle performance of the battery using these batteries.

[0006] Optionally, an inlet and an outlet are respectively formed between the first hot pressing roller and two second hot pressing rollers located at the head and tail ends of the roller group, and the stacked material strip passes through the inlet and the outlet in sequence, and the extrusion gap gradually decreases along the traveling path of the stacked material strip.

[0007] Optionally, along the traveling path, the temperature of each second hot-pressing roller gradually increases.

[0008] Optionally, the temperature difference between two adjacent second hot-pressing rollers is 1-5°C.

[0009] Optionally, the temperature of the first hot pressing roller is T, and the temperature of the first second hot pressing roller on the travel path is t1, satisfying the relationship: T-t1=P, wherein P is 2 to 10, and the unit is ℃.

[0010] Optionally, the temperature of the last second hot-pressing roller on the traveling path is equal to the temperature of the first hot-pressing roller.

[0011] Optionally, the diameter of the second heat-pressing roller is smaller than the diameter of the first heat-pressing roller.

[0012] Optionally, the diameter of the first hot-pressing roller is 100-200 mm, and the diameter of the second hot-pressing roller is 30-100 mm.

[0013] Optionally, all the second heat-pressing rollers are arranged at equal intervals along the circumference of the first heat-pressing roller.

[0014] Optionally, the number of the second hot-pressing rollers is not greater than six.

[0015] In the second aspect, the present application provides a battery cell winding device, including an unwinding mechanism, a winding mechanism and the above-mentioned hot pressing mechanism, the unwinding mechanism is used to output the stacked material tape, the stacked material tape passes through the hot pressing mechanism and the winding mechanism in sequence, and the winding mechanism is used to wind the stacked material tape to form a wound battery cell.

[0016] The beneficial effect of the battery cell winding device provided by the utility model is that the battery cell winding device can improve the detection rate of the battery cell hipot test because it adopts the above-mentioned hot pressing mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A schematic diagram of the structure of a battery cell winding device provided in an embodiment of the utility model;

[0019] Figure 2 A schematic diagram of the structure of a hot pressing mechanism provided in an embodiment of the utility model;

[0020] Figure 3 A schematic structural diagram of a hot pressing mechanism (with the laminated material strip omitted) provided in an embodiment of the utility model.

[0021] Among them, the reference numerals in the figure are:

[0022] 100, hot pressing mechanism; 10, roller group; 20, first hot pressing roller;

[0023] 30. Stacked material belt; 40. Inlet; 50. Outlet;

[0024] 11. Second hot pressing roller; 200. Unwinding mechanism; 210. Positive electrode sheet unwinding assembly;

[0025] 220. Negative electrode sheet unwinding assembly; 230. Diaphragm unwinding assembly; 300. Winding mechanism. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, not all references are to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0028] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0030] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Please refer to Figures 1 to 3 Now, the hot pressing mechanism 100 and the battery cell winding device in the embodiment of the utility model are described.

[0032] Please refer to Figure 2 and Figure 3 The hot pressing mechanism 100 provided in the present application includes a first hot pressing roller 20 and a roller group 10, the roller group 10 includes at least two second hot pressing rollers 11 arranged at intervals along the circumference of the first hot pressing roller 20, each second hot pressing roller 11 is arranged at intervals from the first hot pressing roller 20 to form an extrusion gap for the stacked material strip 30 to pass through, wherein each second hot pressing roller 11 and the first hot pressing roller 20 are used to heat the stacked material strip 30 and jointly extrude the stacked material strip 30.

[0033] It can be understood that the hot pressing mechanism 100 is suitable for battery cell winding equipment, and the laminated material strip 30 mentioned in the present application is a positive electrode sheet material strip, a negative electrode sheet material strip and a separator material strip stacked together. Specifically in the present embodiment, the laminated material strip 30 includes a negative electrode sheet material strip, a separator material strip, a positive electrode sheet material strip and a separator material strip arranged in sequence along the stacking direction. Of course, the structure of the above-mentioned laminated material strip 30 is merely exemplary and should not be regarded as a limitation to the present application.

[0034] After the laminated material strip 30 enters the extrusion gap between the first hot pressing roller 20 and the second hot pressing roller 11, it is pressed together by the two under high temperature. The existing hot pressing mechanism has only two hot pressing rollers arranged opposite to each other. In comparison, firstly, the hot pressing mechanism 100 has at least two second hot pressing rollers 11, that is, the hot pressing mechanism 100 can continuously hot press the laminated material strip 30 at least twice, which is conducive to improving the compaction degree of the laminated material strip 30, that is, improving the tightness between the positive electrode sheet, the negative electrode sheet and the diaphragm. Secondly, since all the second hot pressing rollers 11 are arranged at intervals along the circumference of the first hot pressing roller 20, the laminated material strip 30 is hot pressed in a bent form in the hot pressing mechanism 100, so that the positive electrode sheet, the negative electrode sheet and the diaphragm are evenly stressed, thereby reducing the risk of diaphragm wrinkling and diaphragm and electrode sheet breaking due to excessive tension when the laminated material strip 30 is formed into a battery cell. In this way, the pressing quality of the hot pressing mechanism 100 on the laminated material strip 30 is greatly improved, which is conducive to improving the detection rate of the subsequently formed battery cells in the hipot test and improving the cycle performance of the battery using these battery cells. Among them, the battery cell hipot test can be understood as the battery cell insulation withstand voltage test.

[0035] In another embodiment of the present application, please refer to Figure 3 A feed inlet 40 and a discharge outlet 50 are formed between the first hot pressing roller 20 and the two second hot pressing rollers 11 located at the head and tail ends of the roller group 10, respectively, and the laminated material belt 30 sequentially passes through the feed inlet 40 and the discharge outlet 50. Along the traveling path of the laminated material belt 30, the extrusion gap gradually decreases.

[0036] Specifically, the direction in which the axis of the first hot pressing roller 20 points to the axis of the second hot pressing roller 11 is the first direction, and the first hot pressing roller 20 and each of the second hot pressing rollers 11 have a corresponding first direction. In the first direction, the distance between the first hot pressing roller 20 and the corresponding second hot pressing roller 11 is the size of the extrusion gap. It can be understood that the smaller the extrusion gap between the first hot pressing roller 20 and the second hot pressing roller 11, the greater the extrusion force of the two on the laminated material strip 30. By gradually reducing the extrusion gap along the travel path of the laminated material strip 30, the hot pressing mechanism 100 first hot presses the laminated material strip 30 with a smaller extrusion force, and finally hot presses the laminated material strip 30 with a larger extrusion force, which can reduce the risk of the laminated material strip 30 being wrinkled and the pole piece being broken due to excessive extrusion pressure at the feed port 40.

[0037] In some embodiments, illustratively, the thickness of the laminated material strip 30 before entering the hot pressing mechanism 100 is 200 microns, the number of the second hot pressing rollers 11 is two, and the thickness of the laminated material strip 30 changes twice after entering the hot pressing mechanism 100. The first change is that the thickness of the laminated material strip 30 changes from 200 microns to 197 microns, and the second change is that the thickness of the laminated material strip 30 changes from 197 microns to 195 microns. The above is for the convenience of understanding, so the values ​​of the parameters therein should not be regarded as limitations on the present application.

[0038] In another embodiment of the present application, the temperature of each second hot pressing roller 11 gradually increases along the travel path. That is, the hot pressing mechanism 100 first hot presses the laminated material strip 30 at a lower temperature, and finally hot presses the laminated material strip 30 at a higher temperature. Such an arrangement can avoid uneven heating of the laminated material strip 30 due to the excessively high temperature at the feed port 40 and excessively large temperature difference between the laminated material strip 30 before and after feeding, which is beneficial to improving the lamination quality of the hot pressing mechanism 100.

[0039] In another embodiment of the present application, the temperature difference between two adjacent second hot pressing rollers 11 is 1-5°C. For example, the temperature difference between two adjacent second hot pressing rollers 11 can be 1°C, 2°C, 3°C, 4°C, 5°C, etc., which is not limited here. The above temperature difference value range is obtained by the inventor through practice. When the above temperature difference is 1-5°C, the lamination quality of the laminated material strip 30 by the hot pressing mechanism 100 can be guaranteed.

[0040] In another embodiment of the present application, the temperature of the first hot pressing roller 20 is T, and the temperature of the first second hot pressing roller 11 on the travel path is t1, which satisfies the relationship: T-t1=P, wherein P is 2-10, and the unit is °C. For example, P can be 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. The above relationship is also obtained by the inventor through practice, and when the above relationship is satisfied, the lamination quality of the laminated material strip 30 by the hot pressing mechanism 100 can be guaranteed.

[0041] In another embodiment of the present application, the temperature of the last second hot pressing roller 11 on the travel path is equal to the temperature of the first hot pressing roller 20. This arrangement allows the front and back sides of the laminated material strip 30 to be heated evenly at the discharge port 50, which is beneficial to improving the lamination quality of the hot pressing mechanism 100.

[0042] In another embodiment of the present application, the diameter of the second hot pressing roller 11 is smaller than the diameter of the first hot pressing roller 20. This arrangement, on the one hand, can reduce the overall volume of the hot pressing mechanism 100, thereby reducing its occupied area, and on the other hand, more second hot pressing rollers 11 can be arranged around the first hot pressing roller 20, which is beneficial to improving the lamination quality of the hot pressing mechanism 100.

[0043] In another embodiment of the present application, the diameter of the first hot pressing roller 20 is 100-200 mm, and the diameter of the second hot pressing roller 11 is 30-100 mm. For example, the diameter of the first hot pressing roller 20 can be 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, etc., and the diameter of the second hot pressing roller 11 can be 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc. Through the above arrangement, while ensuring the pressing quality of the hot pressing mechanism 100, the overall volume of the hot pressing mechanism 100 can be reduced, which is conducive to saving materials and achieving the purpose of reducing production costs.

[0044] In another embodiment of the present application, all the second hot pressing rollers 11 are arranged at equal intervals along the circumference of the first hot pressing roller 20. Such an arrangement enables the laminated material strip 30 to be hot pressed by the hot pressing mechanism 100 every time it travels the same distance in the hot pressing mechanism 100, which is beneficial to improving the lamination quality of the hot pressing mechanism 100.

[0045] In another embodiment of the present application, the number of the second hot-pressing rollers 11 is not more than six. Based on practice, when the number of the second hot-pressing rollers 11 is more than six, the improvement of the pressing quality of the hot-pressing mechanism 100 is not significant. Therefore, in order to reduce production costs while ensuring that the pressing quality of the hot-pressing mechanism 100 meets the requirements, in this embodiment, the number of the second hot-pressing rollers 11 is limited to no more than six.

[0046] In some embodiments, illustratively, the temperature of the first hot-pressing roller 20 is 75° C., the number of the second hot-pressing rollers 11 is six, and along the traveling path of the laminated material belt 30, the temperatures of the six second hot-pressing rollers 11 are 65° C., 67° C., 69° C., 71° C., 73° C., and 75° C., respectively. It can be understood that the values ​​of the above parameters can be adjusted as needed, so they should not be regarded as limiting the present application.

[0047] Please refer to Figure 1 The present application also provides a battery cell winding device, which includes an unwinding mechanism 200, a winding mechanism 300 and the above-mentioned hot pressing mechanism 100. The unwinding mechanism 200 is used to output the stacked material strip 30. The stacked material strip 30 passes through the hot pressing mechanism 100 and the winding mechanism 300 in sequence. The winding mechanism 300 is used to wind the stacked material strip 30 to form a wound battery cell. The unwinding mechanism 200 includes a positive electrode unwinding assembly 210 for outputting a positive electrode sheet, a negative electrode unwinding assembly 220 for outputting a negative electrode sheet, and two diaphragm unwinding assemblies 230 for outputting diaphragms. Since the battery cell winding device adopts the above-mentioned hot pressing mechanism 100, the detection rate of the battery cell hipot test can be improved.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hot pressing mechanism, characterized in that: include: A first hot pressing roller (20); A roller group (10), comprising at least two second hot-pressing rollers (11) arranged at intervals along the circumference of the first hot-pressing roller (20), each of the second hot-pressing rollers (11) being arranged at intervals from the first hot-pressing roller (20) to form an extrusion gap for the laminated material strip (30) to pass through; Wherein, each of the second hot-pressing rollers (11) and the first hot-pressing roller (20) is used to heat the laminated material strip (30) and to jointly extrude the laminated material strip (30).

2. The hot pressing mechanism according to claim 1, characterized in that: An inlet (40) and an outlet (50) are respectively formed between the first hot pressing roller (20) and the two second hot pressing rollers (11) located at the head and tail ends of the roller group (10); the stacked material belt (30) passes through the inlet (40) and the outlet (50) in sequence, and the extrusion gap gradually decreases along the travel path of the stacked material belt (30).

3. The hot pressing mechanism according to claim 2, characterized in that: Along the travel path, the temperature of each of the second hot-pressing rollers (11) gradually increases.

4. The hot pressing mechanism according to claim 3, characterized in that: The temperature difference between two adjacent second hot-pressing rollers (11) is 1-5°C.

5. The hot pressing mechanism according to claim 2, characterized in that: The temperature of the first hot pressing roller (20) is T, and the temperature of the first second hot pressing roller (11) on the travel path is t1, satisfying the relationship: T-t1=P, wherein P is 2 to 10, and the unit is °C.

6. The hot pressing mechanism according to claim 2, characterized in that: The temperature of the last second hot-pressing roller (11) on the travel path is equal to the temperature of the first hot-pressing roller (20).

7. The hot pressing mechanism according to any one of claims 1 to 6, characterized in that: The diameter of the second hot-pressing roller (11) is smaller than the diameter of the first hot-pressing roller (20); And / or, the diameter of the first hot pressing roller (20) is 100 to 200 mm, and the diameter of the second hot pressing roller (11) is 30 to 100 mm.

8. The hot pressing mechanism according to any one of claims 1 to 6, characterized in that: All of the second hot-pressing rollers (11) are arranged at equal intervals along the circumference of the first hot-pressing roller (20).

9. The hot pressing mechanism according to any one of claims 1 to 6, characterized in that: The number of the second hot-pressing rollers (11) is no more than six.

10. A battery cell winding device, characterized in that: It comprises an unwinding mechanism (200), a winding mechanism (300) and a hot pressing mechanism (100) as claimed in any one of claims 1 to 9, wherein the unwinding mechanism (200) is used to output the stacked material strip (30), the stacked material strip (30) passes through the hot pressing mechanism (100) and the winding mechanism (300) in sequence, and the winding mechanism (300) is used to wind the stacked material strip (30) to form a wound battery cell.

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