Contact type battery cell preheating furnace

Abstract

The invention provides a contact type battery cell preheating furnace which comprises a furnace body, a plurality of layers of conveying structures used for enabling battery cells to horizontally and linearly flow are arranged in the furnace body, all the layers of conveying structures are arranged up and down, and any layer of conveying structure comprises a first conveying section, a second conveying section and a third conveying section which are sequentially arranged in the horizontal and linear flow direction of the battery cells. The first conveying section is a feeding section and conveys battery cells to the second conveying section, the third conveying section is a discharging section, the second conveying section is used for conveying the battery cells to the third conveying section, and the battery cells are conveyed to the discharging section when the battery cells move from the starting end of the second conveying section to the tail end of the second conveying section one by one. The second conveying section is configured to be capable of heating the upper surface and the lower surface of the battery cell and presetting the thickness of the battery cell, and when the conveying structure conveys the battery cell, the first conveying section, the second conveying section and the third conveying section move synchronously and are the same in conveying speed. According to the invention, the space utilization rate of equipment can be improved, energy is saved, the preheating temperature uniformity is improved, and the battery cell is pre-shaped before the hot pressing process.

Description

Technical Field

[0001] The present invention generally relates to the field of lithium battery technology. More specifically, the present invention relates to a contact-type battery cell preheating furnace. Background Art

[0002] The production process of lithium batteries is relatively complicated. After the bare cells are wound or stacked and before hot pressing and shaping, the lithium battery cells often need to be preheated. The main reason for preheating the cells during lithium battery production is to improve the processing performance and safety of the cells. Preheating the cells before hot pressing can avoid deformation of the cells during hot pressing, and the shaping consistency of the cells is good. Preheating before hot pressing can also make the hot pressing of the cells easier to control for rapid shaping, greatly shortening the shaping process time. When preheating the cells in the prior art, hot air circulation or contact tunnel furnaces are generally used to preheat the cells.

[0003] The traditional view is that the preheating furnace with hot air circulation is more energy-efficient, but the preheating furnace with wind circulation also has obvious problems such as poor temperature uniformity and impurity pollution. For example, the preheating furnace with wind circulation has a blind spot in the flow of hot air, resulting in poor temperature uniformity of the battery cell. For another example, the wind circulation method requires environmental control and wind filtering. First, it will increase the resistance of wind flow, reduce wind speed and thus affect the heating effect. It is necessary to provide a higher initial wind speed to offset the wind resistance factor, but this also increases energy consumption. Second, it increases the replacement cost of the wind filtration structure. Due to the need for environmental control, a filtration structure must be set, but the replacement of the filtration structure itself and the filtration components also brings a higher cost burden. For another example, when the wind is strong, the preheating furnace with wind circulation is easy to blow up the pole ear carried by the battery cell, causing the pole ear to bend, which has a greater impact on the subsequent battery cell shaping process and pole ear welding process. Because the wind circulation preheating furnace needs to provide sufficient space for the flow of hot air, it has a large structure and occupies more space, and the number of batteries that can be preheated in a limited space is reduced. The air circulation method itself has a slow heating speed and requires a longer preheating time to achieve temperature rise, and the energy consumption is not lower than the contact preheating method.

[0004] In the existing contact preheating furnace, the direction of taking and unloading is perpendicular to the movement direction of the battery cells on the conveyor chain plate, and the taking and unloading stations are arranged on both sides of the battery cell conveyor chain plate. The taking and unloading space is large and it cannot be used as a heating area, resulting in a large waste of space; in addition, the material handling on both sides along the battery cell conveying direction to achieve the loading or unloading action also occupies a large site space, and the site space required to complete the overall process of preheating and loading and unloading is relatively high.

[0005] In view of this, there is an urgent need to provide a battery cell preheating furnace to solve the above problems. Summary of the invention

[0006] In order to at least solve one or more technical problems in the above-mentioned background technology, the present invention proposes a contact type battery cell preheating furnace. To this end, the present invention provides the following technical solutions.

[0007] The present invention discloses a contact-type battery cell preheating furnace, comprising a furnace body, wherein the furnace body is provided with multiple layers of conveying structures for making the battery cells flow horizontally and linearly, the conveying structures of each layer are arranged up and down and the orthographic projections of each layer of the conveying structures in the vertical direction overlap, and any layer of the conveying structure comprises a first conveying section, a second conveying section, and a third conveying section which are arranged in sequence along the direction of the horizontal and linear flow of the battery cells, the first conveying section is a loading section and is used to convey the battery cells to the second conveying section, the third conveying section is a unloading section, and the second conveying section is used to convey the battery cells to the third conveying section. During the period when the battery cells move one by one from the starting end of the second conveying section to the end end of the second conveying section, the second conveying section is configured to be able to heat the upper surface and the lower surface of the battery cells and to be able to pre-adjust the thickness of the battery cells. When the conveying structure conveys the battery cells, the first conveying section, the second conveying section, and the third conveying section move synchronously and have the same conveying speed.

[0008] Preferably, the first conveying section, the second conveying section and the third conveying section all have a belt conveying structure, and the adjacent pulleys of the first conveying section and the second conveying section, and the adjacent pulleys of the second conveying section and the third conveying section are connected by a first synchronous belt and a second synchronous belt, respectively.

[0009] Preferably, the second conveying section of any layer of the conveying structure includes a third synchronous belt and a fourth synchronous belt located at the left and right ends thereof, and an annular belt located between the third synchronous belt and the fourth synchronous belt, and the annular belt, the third synchronous belt and the fourth synchronous belt move synchronously and at the same speed, and the upper surface of the upper layer of the annular belt is used to receive the battery cells transported from the first conveying section and transport them to the third conveying section, and the lower surface of the upper layer of the annular belt is provided with a first heating plate, and the first heating plate is fixed relative to the furnace body, and the material of the annular belt is Teflon.

[0010] Preferably, both ends of the endless belt are fixedly connected to U-shaped edges, and the two U-shaped edges are respectively used to be fixedly connected to the third synchronous belt and the fourth synchronous belt located at the left and right ends of the second conveying section.

[0011] Preferably, in the second conveying section of any layer of the conveying structure, the upper surface of the upper layer of the annular belt has a second heating plate that can be raised and lowered, and the projection area of ​​the second heating plate in the vertical direction does not exceed the area where the projection of the annular belt in the vertical direction is located; when the conveying structure stops conveying the battery cells, the second heating plate descends and fits with the upper surface of the battery cells and then clamps and squeezes the battery cells together with the first heating plate; before the conveying structure starts conveying the battery cells, the second heating plate rises and moves away from the upper surface of the battery cells so that the annular belt can convey the battery cells in the direction of the third conveying section when it moves.

[0012] Preferably, the left and right ends of the second heating plate are fixedly connected to guide posts, and the guide posts can move up and down in a vertical direction and can stay at a first preset position. When the guide posts stay at the first preset position, the second heating plate does not contact the upper surface of the battery cell located therebelow; after the guide posts move downward in the vertical direction from the first preset position, the second heating plate can contact the upper surface of the battery cell located below the second heating plate.

[0013] Preferably, a guide support is fixedly arranged on the furnace body, the guide column and the guide support form a sliding pair connection, a roller is provided at the bottom of the guide column, and also includes an inclined wedge that can perform linear reciprocating motion in the horizontal direction, the inclined wedge is used to contact the roller and generate a force on the roller to make the roller move up and down in the vertical direction.

[0014] Preferably, the inclined wedge has a first step and a second step, wherein the upper surfaces of the first step and the second step are both horizontal planes, and there is a transition slope between the first step and the second step, and when the roller is located at the first step, the guide column stays at the first preset position; when the second heating plate contacts the upper surface of the battery cell below the second heating plate, the roller moves along the transition slope to directly above the second step and does not contact the second step, and at this time, the distance between the lowest point of all rollers and the upper surface of the second step below them is in the range of 2~5mm.

[0015] Preferably, it also includes an air expansion component for applying a downward force to the second heating plate, and when the air expansion component expands, it applies a downward force to the second heating plate, so that the second heating plate and the first heating plate can clamp and squeeze the battery cell together, and when the air expansion component expands, the roller gradually moves downward until it contacts the upper surface of the second step, and the air expansion component stops expanding.

[0016] Preferably, the inflatable component comprises an air bag, the air bag is fixedly connected to the furnace body, and when the air bag is inflated, it contacts the second heating plate and exerts a downward force on it.

[0017] The technical solution provided by this application may have the following beneficial effects: 1. The loading and unloading directions of the existing preheating furnace are perpendicular to the conveying direction of the battery cells or the process flow direction of the battery cells. The process flow efficiency of the battery cells is low, and the two sides of the battery cell conveying direction occupy a large space for loading and unloading, which will inevitably cause a waste of space. The present invention connects the loading and unloading positions with the previous and next processes respectively, and the battery cells flow naturally according to the production process. The conveying direction of the battery cells during loading and unloading is consistent with the process flow direction of the battery cells, and the loading and unloading can be cyclic, with a flow mode, and higher production efficiency; the present invention also eliminates the space on both sides of the battery cell conveying chain plate in the existing preheating tunnel furnace, effectively improving the space utilization rate of the limited site.

[0018] Second, because the loading and unloading directions of the existing preheating furnace are perpendicular to the conveying direction of the battery cell, the existing preheating furnace has a large number of claw avoidance positions on the heating plate, which reduces the contact area between the battery cell and the heating plate during heating, resulting in poor heating effect and temperature uniformity, and more energy waste. However, the present invention does not need to set any avoidance positions on the first heating plate or the second heating plate when placing and taking the battery cell in the loading and unloading sections. The structure and heating area of ​​the first heating plate and the second heating plate cannot be affected by the claw avoidance positions. Therefore, the temperature uniformity of the preheating of the battery cell is better. Compared with the structure of the existing preheating furnace with a large number of avoidance positions on the heating plate, the present invention is also more energy-saving.

[0019] 3. In the existing contact preheating furnace, the battery cell is placed on the upper surface of the heating plate in a horizontal state. Due to the uneven surface of the battery cell and / or the heating plate, it is highly likely that the battery cell and the heating plate cannot be completely in contact after being attached, and thus it is impossible to heat the surface of the battery cell more comprehensively, which ultimately leads to poor preheating temperature uniformity of the battery cell, so that the preheating time has to be extended to improve the temperature uniformity. However, the present invention effectively improves the temperature uniformity of the preheating of the battery cell by clamping and squeezing the flat double sides of the battery cell so that the first heating plate and the second heating plate can fully contact the double sides of the battery cell to achieve comprehensive heating, and the preheating purpose can be achieved within a predetermined time, saving energy and improving the preheating efficiency. In addition, during the preheating process, in order to heat the upper surface of the battery cell, the first heating plate and the second heating plate are used to clamp the battery cell and squeeze the battery cell together. At the same time, the action of clamping and squeezing the double sides of the battery cell also realizes the pre-adjustment of the thickness of the battery cell, improves the consistency level of the thickness of the battery cell, achieves the effect of pre-shaping, and makes the subsequent hot pressing process easier to control.

[0020] Fourth, based on the above effects, that is, the present invention has the effect of making the preheating temperature uniformity of the battery cell better. Further, from the perspective of the effect of good preheating temperature uniformity on the processing performance of the battery cell, firstly, good temperature uniformity after preheating can make the battery cell material reach an appropriate temperature, reduce the thermal stress during welding, and thus ensure the firmness and conductivity of the welding joint; secondly, good preheating temperature uniformity can reduce the temperature change of the battery cell during welding, avoid thermal stress caused by rapid temperature changes, and reduce battery cell deformation; furthermore, good preheating temperature uniformity can also make the temperature distribution of the battery cell more uniform during the hot pressing process, reduce the difference in temperature inside the battery cell, and thus improve the stability of the battery cell during processing. From the perspective of the effect of good preheating temperature uniformity on the safety of the battery cell, uniform temperature after preheating can avoid the degradation of battery cell performance or safety hazards caused by temperature fluctuations due to different temperatures at different locations, thereby improving the safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 Schematic diagram showing the internal structure of a furnace body according to an embodiment of the present invention; Figure 2 It is shown Figure 1 A local enlarged view at point A; Figure 3 is a schematic diagram showing the relative positions of the first heating plate, the second heating plate and the annular belt; Figure 4 It is shown Figure 3 A local enlarged view at point B; Explanation of the accompanying drawings: 11, first conveying section; 12, second conveying section; 13, third conveying section; 21, first synchronous belt; 22, second synchronous belt; 31, third synchronous belt; 32, fourth synchronous belt; 33, endless belt; 34, first heating plate; 51, second heating plate; 61, guide column; 71, guide support; 72, roller; 73, inclined wedge; 731, first step; 732, second step; 733, transition slope. DETAILED DESCRIPTION

[0022] Embodiments will now be described with reference to the accompanying drawings. It should be understood that for simplicity and clarity of explanation, reference numerals may be repeated in the accompanying drawings to indicate corresponding or similar elements where deemed appropriate. In addition, the present invention sets forth many specific details in order to provide a thorough understanding of the embodiments described herein. However, it will be appreciated by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other cases, well-known methods, processes, and components are not described in detail to avoid obscuring the embodiments described herein. Moreover, the description should not be construed as limiting the scope of the embodiments described herein.

[0023] According to one embodiment of the present invention, a contact type battery cell preheating furnace is provided. Figures 1 to 4 As shown, it includes a furnace body, and the furnace body has multiple layers of conveying structures for making the battery cells flow horizontally and linearly. The conveying structures of each layer are arranged up and down and the orthographic projections of each layer of the conveying structures in the vertical direction overlap. Any layer of the conveying structure includes a first conveying section 11, a second conveying section 12, and a third conveying section 13 which are arranged in sequence along the horizontal and linear flow direction of the battery cells. The first conveying section 11 is a loading section and is used to convey the battery cells to the second conveying section 12. The third conveying section 13 is a unloading section. The second conveying section 12 is used to convey the battery cells to the third conveying section 13. During the movement of the battery cells one by one from the starting end of the second conveying section 12 to the end of the second conveying section 12, the second conveying section 12 is configured to be able to heat the upper and lower surfaces of the battery cells and to pre-adjust the thickness of the battery cells. When the conveying structure conveys the battery cells, the first conveying section 11, the second conveying section 12, and the third conveying section 13 move synchronously and have the same conveying speed.

[0024] In one embodiment, the first conveying section 11, the second conveying section 12, and the third conveying section 13 can be synchronized and move at the same conveying speed in the following manner. Specifically, the first conveying section 11, the second conveying section 12, and the third conveying section 13 can all use a belt conveying structure, and the pulleys adjacent to the first conveying section 11 and the second conveying section 12, and the pulleys adjacent to the second conveying section 12 and the third conveying section 13 are respectively connected by the first synchronous belt 21 and the second synchronous belt 22. The pulleys connected by the first synchronous belt 21 and the second synchronous belt 22 can be arranged at the ends of the rotating shaft after the rotating shaft coaxially arranged with the pulleys is extended in the axial direction.

[0025] The second conveying section 12 mentioned above is configured to heat the lower surface of the battery cell, which can be achieved by the following technical means. Specifically, the second conveying section 12 of any layer of the conveying structure includes a third synchronous belt 31 and a fourth synchronous belt 32 located at the left and right ends thereof, and an annular belt 33 located between the third synchronous belt 31 and the fourth synchronous belt 32. The annular belt 33, the third synchronous belt 31 and the fourth synchronous belt 32 move synchronously and at the same speed. The upper surface of the upper layer of the annular belt 33 is used to receive the battery cell transported from the first conveying section 11 and transport it to the third conveying section 13. The lower surface of the upper layer of the annular belt 33 is provided with a first heating plate 34, which is fixedly arranged relative to the furnace body, and the material of the annular belt 33 is Teflon. The first heating plate 34 can be fixed by using a profile as its horizontally arranged cross brace, and the two ends of the profile are respectively fixedly connected to the furnace body, thereby fixing the first heating plate 34.

[0026] The third synchronous belt 31, the fourth synchronous belt 32, and the endless belt 33 mentioned above move synchronously and at the same speed, which can be achieved by the following technical means. Specifically, the two ends of the endless belt 33 are fixedly connected to the U-shaped edges, and the two U-shaped edges are respectively used to be fixedly connected to the third synchronous belt 31 and the fourth synchronous belt 32 located at the left and right ends of the second conveying section 12. It can be understood that the movement of the endless belt 33 mainly depends on the movement of the third synchronous belt 31 and the fourth synchronous belt 32.

[0027] The second conveying section 12 mentioned above is configured to heat the upper surface of the battery cell, which is mainly achieved by the following technical means. Specifically, the upper surface of the upper layer of the annular belt 33 of the second conveying section 12 of any layer of the conveying structure has a second heating plate 51 that can be raised and lowered, and the projection area of ​​the second heating plate 51 in the vertical direction does not exceed the projection area of ​​the annular belt 33 in the vertical direction; when the conveying structure stops conveying the battery cell, the second heating plate 51 descends and fits with the upper surface of the battery cell and then clamps and squeezes the battery cell together with the first heating plate 34; before the conveying structure starts conveying the battery cell, the second heating plate 51 rises and moves away from the upper surface of the battery cell, so that when the annular belt 33 moves to the direction where the third conveying section 13 is located, the battery cell is not hindered by the second heating plate 51 fitting the battery cell.

[0028] The second heating plate 51 mentioned above can be raised and lowered in the vertical direction, which can be achieved by the following technical means. For example, guide posts 61 can be fixedly connected to the left and right ends of the second heating plate 51, and the guide posts 61 can move up and down in the vertical direction and can stay at the first preset position, that is, the vertical lifting movement of the second heating plate 51 is achieved by the movement of the guide posts 61 in the vertical direction.

[0029] In addition, when the guide column 61 stays at the first preset position, the second heating plate 51 does not contact the upper surface of the battery cell located below it; after the guide column 61 moves downward in the vertical direction from the first preset position, the second heating plate 51 can contact the upper surface of the battery cell located below the second heating plate 51.

[0030] The guide column 61 can move up and down in the vertical direction by the following means. Specifically, a guide support 71 can be fixedly arranged on the furnace body, wherein the guide column 61 and the guide support 71 form a sliding pair connection, and the bottom of the guide column 61 is provided with a roller 72, and also includes an inclined wedge 73 that can perform linear reciprocating motion in the horizontal direction, and the inclined wedge 73 is used to contact the roller 72 and generate a force on the roller 72 to make the roller 72 move up and down in the vertical direction, thereby realizing the lifting and lowering movement of the guide column 61.

[0031] The wedge 73 performs linear reciprocating motion in the horizontal direction, which can be specifically achieved by using a cylinder control.

[0032] The guide column 61 can stay at the first preset position by providing a horizontal step on the inclined wedge 73. Specifically, the inclined wedge 73 has a first step 731 and a second step 732, wherein the upper surfaces of the first step 731 and the second step 732 are both horizontal planes, and there is a transition slope 733 between the first step 731 and the second step 732. When the roller 72 is located at the first step 731, the guide column 61 stays at the first preset position. It is easy to understand that if the bottom roller 72 of the guide column 61 is located at the first step 731 by using the inclined wedge 73, if the guide column 61 is defined as being located at the first preset position at this time, then the position of the second heating plate 51 at this time is the highest position it can reach.

[0033] The second conveying section 12 mentioned above is configured to also be able to pre-adjust the thickness of the battery cell, which can be achieved through the following technical means.

[0034] When the second heating plate 51 contacts the upper surface of the battery cell below the second heating plate 51 , the roller 72 moves along the transition slope 733 to just above the second step 732 and does not contact the second step 732 , and at this time, the distance between the lowest point of all rollers 72 and the upper surface of the second step 732 below them is in the range of 2 to 5 mm.

[0035] What is defined above is that when the roller 72 descends from the first preset position along the transition slope 733, when the second heating plate 51 can fit the upper surface of the battery cell, the roller 72 should not contact the second step 732. In this way, when a downward force is applied to the second heating plate 51, the battery cell can be pre-compressed.

[0036] At the same time, since the roller 72 is not in contact with the second step 732, that is, the second heating plate 51 still has space to move downward to pre-extrude the battery cell. Therefore, in order to prevent excessive extrusion of the battery cell, when the roller 72 moves downward and contacts the second step 732, the second step 732 constitutes an obstacle to the continued movement of the roller 72, that is, the second step 732 acts as a limiting structure to limit the movement of the roller 72. Through the extrusion of the battery cell in the above steps, the distance range between the lowest point of the roller 72 and the upper surface of the second step 732 located directly below it is eliminated, thereby ensuring the consistency of the thickness of the battery cell.

[0037] The above-mentioned specific structure of the second heating plate 51 contacting and squeezing the upper surface of the battery cell has been proposed, and also includes a gas expansion component for applying a downward force to the second heating plate 51. When the gas expansion component expands, it applies a downward force to the second heating plate 51, so that the second heating plate 51 and the first heating plate 34 clamp and squeeze the battery cell together. When the gas expansion component expands, the roller 72 gradually moves downward until it contacts the upper surface of the second step 732, and the gas expansion component stops expanding. In this way, the stroke of all rollers 72 is the same, so that the second heating plate 51 can be lowered to the same height, and then the degree of squeezing the battery cell is the same, which further improves the consistency of the thickness of the battery cell.

[0038] The above-mentioned inflatable component includes an airbag, which can be fixedly connected to the furnace body, and when the airbag is expanded, it contacts the second heating plate 51 and generates a downward force on the second heating plate 51 .

[0039] It should be understood that the possible terms "first" or "second" etc. in the claims, specifications and drawings disclosed in the present invention are used to distinguish different objects rather than to describe a specific order. The terms "include" and "comprise" used in the specifications and claims disclosed in the present invention indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0040] It should also be understood that the terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used in the disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in the disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.

[0041] Although the embodiments of the present invention are as described above, the contents are only examples used to facilitate understanding of the present invention, and are not intended to limit the scope and application scenarios of the present invention. Any technician in the technical field of the present invention can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention, but the scope of patent protection of the present invention shall still be based on the scope defined by the attached claims.

Claims

1. A contact type battery cell preheating furnace, comprising a furnace body, characterized in that: The furnace body has multiple layers of conveying structures for allowing the battery cells to flow horizontally and linearly. The conveying structures of each layer are arranged up and down and their orthographic projections in the vertical direction overlap. Any layer of the conveying structures comprises a first conveying section (11), a second conveying section (12) and a third conveying section (13) which are arranged in sequence along the direction of the horizontal linear flow of the battery cells. The first conveying section (11) is a loading section and is used to convey the battery cells to the second conveying section (12). The third conveying section (13) is a unloading section. The second conveying section (12) is used to convey the battery cells to the third conveying section (13). During the period when the battery cells move one by one from the starting end of the second conveying section (12) to the end of the second conveying section (12), the second conveying section (12) is configured to heat the upper surface and the lower surface of the battery cells and to pre-adjust the thickness of the battery cells. When the conveying structure conveys the battery cells, the first conveying section (11), the second conveying section (12) and the third conveying section (13) move synchronously and at the same conveying speed.

2. A contact type battery cell preheating furnace according to claim 1, characterized in that: The first conveying section (11), the second conveying section (12) and the third conveying section (13) all have a belt transmission structure, and the adjacent pulleys of the first conveying section (11) and the second conveying section (12), and the adjacent pulleys of the second conveying section (12) and the third conveying section (13) are respectively connected by a first synchronous belt (21) and a second synchronous belt (22).

3. A contact type battery cell preheating furnace according to claim 1, characterized in that: The second conveying section (12) of any one layer of the conveying structure comprises a third synchronous belt (31) and a fourth synchronous belt (32) located at left and right ends thereof, and an annular belt (33) located between the third synchronous belt (31) and the fourth synchronous belt (32); the annular belt (33), the third synchronous belt (31) and the fourth synchronous belt (32) move synchronously and at the same speed; the upper surface of the upper layer of the annular belt (33) is used to receive the battery cells transported from the first conveying section (11) and transport them to the third conveying section (13); the lower surface of the upper layer of the annular belt (33) is provided with a first heating plate (34); the first heating plate (34) is fixedly arranged relative to the furnace body; and the material of the annular belt (33) is Teflon.

4. A contact type battery cell preheating furnace according to claim 3, characterized in that: The two ends of the endless belt (33) are fixedly connected to U-shaped edges, and the two U-shaped edges are respectively used to be fixedly connected to the third synchronous belt (31) and the fourth synchronous belt (32) located at the left and right ends of the second conveying section (12).

5. The contact type battery cell preheating furnace according to claim 3, characterized in that: The second conveying section (12) of any layer of the conveying structure has an upper surface of the upper layer of the annular belt (33) having a second heating plate (51) that can be raised and lowered, and the projection area of ​​the second heating plate (51) in the vertical direction does not exceed the projection area of ​​the annular belt (33) in the vertical direction; when the conveying structure stops conveying the battery cell, the second heating plate (51) descends and adheres to the upper surface of the battery cell, and then clamps and squeezes the battery cell together with the first heating plate (34); before the conveying structure starts conveying the battery cell, the second heating plate (51) rises and moves away from the upper surface of the battery cell so that the annular belt (33) conveys the battery cell in the direction of the third conveying section (13) when it moves.

6. A contact type battery cell preheating furnace according to claim 5, characterized in that: The left and right ends of the second heating plate (51) are fixedly connected to guide posts (61); the guide posts (61) can move up and down in a vertical direction and can stay at a first preset position; when the guide posts (61) stay at the first preset position, the second heating plate (51) is not in contact with the upper surface of the battery cell located below it; after the guide posts (61) move downward in the vertical direction from the first preset position, the second heating plate (51) can be in contact with the upper surface of the battery cell located below the second heating plate (51).

7. A contact type battery cell preheating furnace according to claim 6, characterized in that: A guide support (71) is fixedly arranged on the furnace body, the guide column (61) and the guide support (71) are connected to form a sliding pair, a roller (72) is arranged at the bottom of the guide column (61), and also includes an inclined wedge (73) capable of linear reciprocating motion in a horizontal direction, the inclined wedge (73) is used to contact the roller (72) and generate a force on the roller (72) so that the roller (72) can move up and down in a vertical direction.

8. The contact type battery cell preheating furnace according to claim 7, characterized in that: The inclined wedge (73) has a first step (731) and a second step (732), wherein the upper surfaces of the first step (731) and the second step (732) are both horizontal surfaces, and a transition inclined surface (733) is provided between the first step (731) and the second step (732); when the roller (72) is located at the first step (731), the guide column (61) stays at the first preset position; when the second heating plate (51) contacts the upper surface of the battery cell located below the second heating plate (51), the roller (72) moves along the transition inclined surface (733) to the position directly above the second step (732) and does not contact the second step (732), and at this time, the distance between the lowest point of all rollers (72) and the upper surface of the second step (732) located below them is in the range of 2 to 5 mm.

9. The contact type battery cell preheating furnace according to claim 8, characterized in that: It also includes an air expansion component for applying a downward force to the second heating plate (51); when the air expansion component expands, it applies a downward force to the second heating plate (51), so that the second heating plate (51) and the first heating plate (34) jointly clamp and squeeze the battery cell; when the air expansion component expands, the roller (72) gradually moves downward until it contacts the upper surface of the second step (732), and the air expansion component stops expanding.

10. A contact type battery cell preheating furnace according to claim 9, characterized in that: The air expansion component comprises an air bag, the air bag is fixedly connected to the furnace body, and when the air bag expands, it contacts the second heating plate (51) and generates a downward force on it.

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