Lithium battery diaphragm baking device

Abstract

The utility model discloses a lithium battery diaphragm baking device, and relates to the technical field of lithium battery diaphragm production, and the lithium battery diaphragm baking device comprises an unwinding assembly used for unwinding a diaphragm material; the coating mechanism is used for coating a coating on the surface of one side of the membrane material; the winding assembly is arranged opposite to the coating mechanism and is used for winding the film material; and the laser heating assembly is arranged between the unwinding assembly and the coating mechanism and is used for heating the membrane material. According to the technical scheme provided by the utility model, the membrane material can be heated more uniformly, the membrane material is heated uniformly and has better physicochemical property and consistency under the condition that other process conditions are not changed, the difference of various physicochemical properties caused by non-uniform heating of a surface membrane surface and an inner layer is reduced, and the charge-discharge performance and the energy density of a battery product are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery separator production, in particular to a baking device for lithium battery separators. Background Art

[0002] The membrane material is an indispensable and important part of the battery. In recent years, due to the large-scale application of lithium-ion batteries, especially power batteries, higher requirements have been put forward for the energy density, cycle performance, charge and discharge current density, and safety performance of the battery; the improvement of the membrane material performance plays a crucial role in the improvement of the comprehensive performance of the battery.

[0003] At present, the dry single-direction stretching process is adopted to produce lithium battery separators in China. The key processes include heat treatment - cold drawing - hot drawing - shaping. Each key step requires temperature treatment of the separator. The existing dry single-direction stretching technology heats the separator through the oil temperature inside the roller or the air flow circulation in the oven. During the stretching process, the oil temperature heating inside the roller can only make the surface of the composite separator uniformly heated, while the inner layer of the separator is unevenly heated. When heating in the oven, the uneven heating of the film surface will be caused due to the difference in the oven temperature consistency. Under the condition that other stretching process conditions remain unchanged, both methods will cause differences in various physical and chemical properties due to the uneven heating of the surface film and the inner layer, affecting the charge and discharge performance and energy density of the battery products. Summary of the Utility Model

[0004] The main purpose of the utility model is to propose a baking device for lithium battery separators, aiming to make the membrane material more evenly heated.

[0005] To achieve the above purpose, the baking device for lithium battery separators proposed by the utility model includes:

[0006] A transmission mechanism, which is arranged to drive the movement of the membrane material;

[0007] A laser heating component, the position of which corresponds to that of the transmission mechanism, and the laser heating component is used to heat the membrane material transmitted by the transmission mechanism.

[0008] In an embodiment, the baking device for lithium battery separators further includes a chassis, the chassis is arranged above the transmission mechanism, the chassis has an opening, the opening is opposite to the transmission mechanism, the number of the laser heating components is multiple groups, and multiple groups of the laser heating components are installed in the chassis at intervals.

[0009] In an embodiment, the laser heating component includes:

[0010] A heat treatment heating component, a cold drawing heating component, a hot drawing heating component, and a shaping heating component that are sequentially arranged along the first direction;

[0011] The heat treatment heating component, the cold drawing heating component, the hot drawing heating component, and the shaping heating component are used to heat the film material at corresponding positions.

[0012] In one embodiment, the chassis further includes: a first baffle, a second baffle, and a third baffle;

[0013] The first baffle is arranged between the heat treatment heating component and the cold drawing heating component;

[0014] The second baffle is arranged between the cold drawing heating component and the hot drawing heating component;

[0015] The third baffle is arranged between the hot drawing heating component and the shaping heating component.

[0016] In one embodiment, the lithium battery separator baking device further includes: an exhaust component, the exhaust component includes an exhaust fan and an exhaust pipe, a cross beam is arranged in the chassis, the exhaust fan is connected to the cross beam, an exhaust port is arranged in the chassis, one end of the exhaust pipe is connected to the exhaust fan, and the other end of the exhaust pipe is connected to the exhaust port.

[0017] In one embodiment, the laser heating component is arranged on either one side or opposite sides of the film material.

[0018] In one embodiment, the laser heating component includes a laser source and a laser homogenizer, the laser source is arranged on the chassis, the laser homogenizer is connected to the laser source, and the laser emitted by the laser source is homogenized by the laser homogenizer and then irradiates on the film material to uniformly heat the film material.

[0019] In one embodiment, the laser source is a multi-mode laser source.

[0020] In one embodiment, the transmission mechanism includes:

[0021] A unwind component, the unwind component is used to unwind the film material;

[0022] A rewind component, which is arranged opposite to the unwind component and is used to rewind the film material;

[0023] A stretching component, the stretching component is arranged between the unwind component and the rewind component and is used to perform multi-stage stretching on the film material.

[0024] In one embodiment, the unwind component includes:

[0025] An unwind roller, the unwind roller is used to unwind the film material;

[0026] A pressure roller, the pressure roller abuts against the film material and is used to apply pressure to the unwound film material;

[0027] The driving roller is disposed opposite to the unwinding assembly and is used to drive the film material to move in the direction from the driving roller to the winding assembly.

[0028] Through the adoption of the laser heating assembly to heat the film material, the technical solution of the present utility model can make the film material be heated more evenly. Under the condition that other process conditions remain unchanged, the film material is evenly heated, has better physical and chemical properties and consistency, reduces the differences in various physical and chemical properties caused by uneven heating of the surface film and the inner layer, and improves the charge and discharge performance and energy density of the battery product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0030] Figure 1 It is a schematic structural diagram of an embodiment of the lithium battery separator baking device provided by the present utility model.

[0031] Figure 2 It is a schematic structural diagram of another embodiment of the lithium battery separator baking device provided by the present utility model.

[0032] Explanation of the reference numerals in the drawings:

[0033] 1. Transmission mechanism; 11. Unwinding assembly; 111. Unwinding roller; 112. Pressure roller; 113. Driving roller; 12. Winding assembly; 13. Tensile assembly; 131. First heat treatment roller; 132. Second heat treatment roller; 133. First cold drawing roller; 134. Second cold drawing roller; 135. First hot drawing roller; 136. Second hot drawing roller; 137. First shaping roller; 138. Second shaping roller; 2. Film material; 3. Laser heating assembly; 31. Laser source; 32. Laser homogenizer; 301. Heat treatment heating assembly; 302. Cold drawing heating assembly; 303. Hot drawing heating assembly; 304. Shaping heating assembly; 4. Chassis; 41. First baffle; 42. Second baffle; 43. Third baffle; 44. Cross beam; 5. Exhaust assembly; 51. Exhaust fan; a. Heat treatment section; b. Cold drawing section; c. Hot drawing section; d. Shaping section; e. Preheating section.

[0034] The realization of the purpose, functional features and advantages of the present utility model will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative work belong to the scope of protection of the present utility model.

[0036] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0037] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0038] Currently, the key processes in the production of lithium battery separators by the dry process unidirectional stretching process are heat treatment - cold drawing - hot drawing - shaping. Each key step requires temperature treatment of the separator. The existing dry process unidirectional stretching technology heats the separator through the oil temperature inside the roller or the air flow circulation in the oven. During the stretching process, heating the oil temperature inside the roller can only make the surface layer of the composite separator heat evenly, while the inner layer of the separator is unevenly heated. When heating in the oven, the film surface is unevenly heated due to the difference in oven temperature consistency.

[0039] In order to make the film material 2 heat more evenly, the present utility model proposes a lithium battery separator baking device.

[0040] Please refer to Figure 1 and Figure 2 , in an embodiment of the present utility model, the lithium battery separator baking device includes a transmission mechanism 1 and a laser heating component 3. The transmission mechanism 1 is arranged to drive the movement of the film material 2. The position of the laser heating component 3 corresponds to that of the transmission mechanism 1, and the laser heating component 3 is used to heat the film material 2 driven by the transmission mechanism 1.

[0041] In this embodiment, the laser heating assembly 3 generates laser, and the laser irradiates the film material 2 located on the transmission mechanism 1 to heat the film material 2. By allowing the laser generated by the laser heating assembly 3 to uniformly irradiate the film material 2, the film material 2 can be heated more uniformly under the condition that other process conditions remain unchanged, enabling the prepared separator to have better physical and chemical properties and consistency, reducing the differences in various physical and chemical properties caused by uneven heating of the surface film and the inner layer, and improving the charge and discharge performance and energy density of the battery product.

[0042] In this embodiment, laser heating can control the heating intensity and range by adjusting parameters such as the power, irradiation time, and scanning speed of the laser beam. This adjustability enables precise control of laser heating according to specific requirements, thereby achieving a more uniform heating effect on the film material 2. Moreover, the response speed of laser heating is very fast, and heat energy can be provided on a time scale of milliseconds or microseconds. This allows the laser to achieve rapid heating and cooling processes, thereby reducing the conduction or convection process of heat energy within the object and facilitating a more uniform heating effect.

[0043] In an embodiment of the present utility model, the lithium battery separator baking device further includes a chassis 4. The chassis 4 is disposed above the transmission mechanism 1. The chassis 4 has an opening opposite to the transmission mechanism 1. The number of laser heating assemblies 3 is multiple groups, and the multiple groups of laser heating assemblies 3 are installed at intervals within the chassis 4.

[0044] In this embodiment, using multiple groups of laser heating assemblies 3 to heat and bake the film material 2 can be more uniform. It can be understood that by using multiple groups of laser heating assemblies 3, it is also possible to adjust multiple different laser heating assemblies 3 to have different heating temperatures, which is applicable to the processes of heat treatment - cold drawing - hot drawing - shaping in the dry process unidirectional stretching process.

[0045] In an embodiment, the laser heating assembly 3 includes a heat treatment heating assembly 301, a cold drawing heating assembly 302, a hot drawing heating assembly 303, and a shaping heating assembly 304 arranged in sequence along the first direction.

[0046] The heat treatment heating assembly 301, the cold drawing heating assembly 302, the hot drawing heating assembly 303, and the shaping heating assembly 304 are used to heat the corresponding parts of the film material 2.

[0047] In an embodiment, the transmission mechanism 1 includes a film unwinding assembly 11, a film winding assembly 12, and a stretching assembly 13. The film unwinding assembly 11 is used to unwind the film material 2. The film winding assembly 12 is disposed opposite to the film unwinding assembly 11 and is used to wind the film material 2. The stretching assembly 13 is disposed between the film unwinding assembly 11 and the film winding assembly 12 and is used to perform multi-stage stretching on the film material 2.

[0048] Specifically, in order to be applicable to the dry unidirectional stretching process, in some embodiments, the stretching assembly 13 includes a first heat treatment roller 131, a second heat treatment roller 132, a first cold drawing roller 133, a second cold drawing roller 134, a first hot drawing roller 135, a second hot drawing roller 136, a first shaping roller 137, and a second shaping roller 138 that are sequentially arranged with intervals therebetween.

[0049] Wherein, a heat treatment section a is formed between the first heat treatment roller 131 and the second heat treatment roller 132. A cold drawing section b is formed between the first cold drawing roller 133 and the second cold drawing roller 134. A hot drawing section c is formed between the first hot drawing roller 135 and the second hot drawing roller 136. A shaping section d is formed between the first shaping roller 137 and the second shaping roller 138. By controlling the speed ratios among the first heat treatment roller 131, the second heat treatment roller 132, the first cold drawing roller 133, the second cold drawing roller 134, the first hot drawing roller 135, the second hot drawing roller 136, the first shaping roller 137, and the second shaping roller 138, stretching of the film material in different processes can be achieved.

[0050] It can be understood that in some embodiments, the number of heat treatment rollers, cold drawing rollers, etc. is not limited to two, and can also be set to multiple. Increasing the number of rollers can achieve multi-point stretching and make the pore uniformity of the film material better.

[0051] The heat treatment heating assembly 301, the cold drawing heating assembly 302, the hot drawing heating assembly 303, and the shaping heating assembly 304 are respectively arranged corresponding to the heat treatment section a, the cold drawing section b, the hot drawing section c, and the shaping section d. By adjusting the powers of the heat treatment heating assembly 301, the cold drawing heating assembly 302, the hot drawing heating assembly 303, and the shaping heating assembly 304, the heating temperature of the film material 2 in the heat treatment section a, the cold drawing section b, the hot drawing section c, and the shaping section d can be adjusted, so as to adapt to the process requirements of the baking temperature in the heat treatment - cold drawing - hot drawing - shaping process of the dry unidirectional stretching process.

[0052] In one embodiment, the heat treatment heating assembly 301 uniformly heats the film material 2 located in the heat treatment section a to 140 - 148 °C.

[0053] In one embodiment, the cold drawing heating assembly 302 uniformly heats the film material 2 located in the cold drawing section b to 48 °C - 120 °C.

[0054] In one embodiment, the hot drawing heating assembly 303 uniformly heats the film material 2 located in the hot drawing section c to 140 °C - 160 °C.

[0055] In one embodiment, the shaping heating assembly 304 uniformly heats the film material 2 located in the shaping section d to 70 °C - 155 °C.

[0056] In one embodiment, the chassis 4 further includes a first baffle 41, a second baffle 42, and a third baffle 43.

[0057] The first baffle 41 is disposed between the heat treatment heating component 301 and the cold drawing heating component 302. The first baffle 41 is used to separate the heat treatment section a and the cold drawing section b, preventing air circulation between the heat treatment section a and the cold drawing section b and generating temperature interference.

[0058] The second baffle 42 is disposed between the cold drawing heating component 302 and the hot drawing heating component 303. The second baffle 42 is used to separate the cold drawing section b and the hot drawing section c, preventing air circulation between the cold drawing section b and the hot drawing section c and generating temperature interference.

[0059] The third baffle 43 is disposed between the hot drawing heating component 303 and the shaping heating component 304. The third baffle 43 is used to separate the hot drawing section c and the shaping section d, preventing air circulation between the hot drawing section c and the shaping section d and generating temperature interference.

[0060] During the manufacturing process, if dust adheres to the film surface of the film material 2, it will cause minor defects in the film material 2 during the stretching process, resulting in the film surface of the film material 2 cracking in subsequent processes. To solve this problem, in one embodiment, the lithium battery separator baking device further includes an exhaust component 5. The exhaust component 5 includes an exhaust fan 51 and an exhaust pipe. A cross beam 44 is provided in the chassis 4. The exhaust fan 51 is connected to the cross beam 44. An exhaust port is provided in the chassis 4. One end of the exhaust pipe is connected to the exhaust fan 51, and the other end of the exhaust pipe is connected to the exhaust port.

[0061] In this embodiment, the air in the chassis 4 is exhausted through the exhaust fan 51 and the exhaust pipe, reducing the amount of dust settling on the film surface of the film material 2, preventing dust from adhering to the film surface of the film material 2, causing minor defects in the film material 2 during the stretching process, and resulting in the film surface of the film material 2 cracking in subsequent processes.

[0062] In one embodiment, the laser heating component 3 is disposed on either one or opposite sides of the film material 2.

[0063] In this embodiment, Figure 1 Taking the orientation in

[0064] In one embodiment, the laser heating assembly 3 includes a laser source 31 and a laser homogenizer 32. A laser homogenizer is an optical element used to homogenize the intensity distribution of a laser beam. Its main function is to convert the input high-speckle laser beam into a uniform output with an approximate Gaussian or flat-top beam intensity distribution. The laser source 31 is disposed on the chassis 4, the laser homogenizer 32 is connected to the laser source 31, and the laser emitted by the laser source 31 is homogenized by the laser homogenizer 32 and then irradiates on the film material 2 to uniformly heat the film material 2.

[0065] In one embodiment, since a single-mode laser beam is more concentrated in focus, although it can provide extremely high energy density, it may be difficult to achieve ideal uniformity in large-area heating or applications requiring uniform heating. To achieve uniform heating, the laser source 31 is preferably a multi-mode laser source. Because the multi-mode laser source contains multiple modes in its beam, these modes form a relatively complex interference pattern in space, resulting in a relatively more dispersed distribution of energy in the processing area. For thin-film heating, this energy dispersion characteristic helps to achieve a wider heating area and higher heating uniformity, which is important for applications that require precise temperature control during the heating process and avoid material damage caused by local overheating. Moreover, due to the larger spot size of the multi-mode laser, it can act on a larger area in the same time, thus improving the heating efficiency.

[0066] In one embodiment, the unwinding assembly 11 includes an unwinding roller 111, a pressing roller 112, and a driving roller 113.

[0067] The unwinding roller 111 is used to unwind the film material 2. The pressing roller 112 abuts against the film material 2 and is used to apply pressure to the unwound film material 2. By applying appropriate pressure to the film material 2 through the pressing roller 112, the air in the film material 2, especially in a multi-layer composite film, can be discharged, avoiding wrinkles on the film surface caused by gas. The driving roller 113 is disposed opposite to the unwinding assembly 11 and is used to drive the film material 2 to move in the direction from the driving roller 113 to the winding assembly 12.

[0068] In one embodiment, the stretching assembly 13 further includes a preheating section e. A preheating section e is formed between the driving roller 113 and the first heat treatment roller 131, and a laser heating assembly 3 is correspondingly disposed on one side of the preheating section e to heat it. The laser heating assembly 3 uniformly heats the film material 2 located in the preheating section e to 40°C.

[0069] In one embodiment, the distance between the laser heating assembly 3 and the film material 2 is 50 cm - 100 cm.

[0070] Example 1

[0071] The cast polyolefin film uses a polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm.

[0072] (1) Heat treatment

[0073] A polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm is set on an unwinding assembly 111 with a speed of 2 m / min and a first heat treatment roller 131. The laser source 31 evenly heats the film material 2 located in the preheating section e to 40°C. The first heat treatment roller 131 has a speed of 2 m / min, the stretching ratio in preheating is 1, and the preheating temperature in the preheating section e is 40°C; the laser source 31 evenly heats the film material 2 located in the preheating section e to 140°C. The second heat treatment roller 132 has a speed of 2 m / min, the stretching ratio in heat treatment is 1, and the heat treatment temperature is 140°C.

[0074] (2) Cold drawing

[0075] The polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm is set on a first cold drawing roller 133 with a speed of 2 m / min and a second cold drawing roller 134 with a speed of 2.4 m / min. The cold drawing ratio is 1.2, and the laser irradiation temperature is set to 80°C and irradiated on the film surface to make the cold drawing temperature 80°C.

[0076] (3) Hot drawing

[0077] The polypropylene film material 2 after cold drawing is set on a first hot drawing roller 135 with a speed of 2.4 m / min and a second hot drawing roller 136 with a speed of 5.19 m / min. Heat drawing is formed by using the speed difference, the heat drawing ratio is 2.1, and the laser irradiation temperature is set to 130°C and irradiated on the film surface to make the heat drawing temperature 130°C.

[0078] (4) Shaping

[0079] The polypropylene film material 2 after heat drawing is set on a first shaping roller 137 and a second shaping roller 138 with a traveling speed of 4.1 m / min. Shaping drawing is formed by using the speed difference, the shaping ratio is 0.8, and the laser irradiation temperature is set to 135°C and irradiated on the film surface to make the shaping temperature 135°C.

[0080] Comparative Example 1

[0081] In the device of this comparative example, there is no laser heating component, and the processing temperature is controlled by the roller temperature. The cast polyolefin film selects the polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm.

[0082] Heat treatment

[0083] The polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm is wound in a heat treatment oven and annealed at 140°C for 16 hours.

[0084] (1) Cold drawing

[0085] A polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm is set between a first cold drawing roll 133 with a speed of 2 m / min and a temperature of 40°C and a second cold drawing roll 134 with a speed of 2.4 m / min and a temperature of 60°C. Cold drawing is formed using the speed difference, the cold drawing speed ratio is 1.2, the temperature of the film material 2 is controlled by the cold drawing rolls, and the cold drawing temperature is 60°C.

[0086] (2) Hot drawing

[0087] The polypropylene film material 2 after cold drawing is set between a first hot drawing roll 135 with a speed of 2.4 m / min and a temperature of 130°C and a second hot drawing roll 136 with a speed of 5.19 m / min and a temperature of 130°C. Hot drawing is formed using the speed difference, the hot drawing speed ratio is 2.1, the temperature of the film material 2 is controlled by the hot drawing rolls, and the hot drawing temperature is 130°C

[0088] (3) Shaping

[0089] The polypropylene film material 2 after hot drawing is set between a first shaping roll 137 with a traveling speed of 4.1 m / min and a temperature of 135°C and a second shaping roll 138. Shaping drawing is formed using the speed difference, the shaping speed ratio is 0.8, the temperature of the film material 2 is controlled by the shaping rolls, and the shaping temperature is 135°C.

[0090] Comparative Example 2

[0091] In this comparative example device, there is no laser heating component, and the processing temperature is controlled by an oven. The cast polyolefin film selects a polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm.

[0092] (1) Heat treatment

[0093] The polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm is set on a unwind assembly 111 with a speed of 2 m / min and a first heat treatment roll 131. The oven temperature is set at 40°C to bake and heat the film material 2. The speed of the first heat treatment roll 131 is 2 m / min, the preheating drawing speed ratio is 1, and the preheating temperature is 40°C; the oven temperature is set at 140°C to bake and heat the film material 2. The speed of the second heat treatment roll 132 is 2 m / min, the heat treatment drawing speed ratio is 1, and the heat treatment temperature is 140°C.

[0094] (2) Cold drawing

[0095] The polypropylene film material 2 with a width of 1000 mm and a thickness of 15 μm is set between a first cold drawing roll 133 with a speed of 2 m / min and a second cold drawing roll 134 with a speed of 2.4 m / min. The cold drawing speed ratio is 1.2. The oven temperature is set at 80°C to bake and heat the film material 2 to make the cold drawing temperature 80°C.

[0096] (3) Thermal stretching

[0097] Place the polypropylene film material 2 that has completed cold stretching between the first thermal stretching roller 135 with a speed of 2.4 m / min and the second thermal stretching roller 136 with a speed of 5.19 m / min, and form thermal stretching by using the speed difference. The thermal stretching speed ratio is 2.1. Set the oven temperature to 130 °C to bake and heat the film material 2, so that the thermal stretching temperature is 130 °C.

[0098] (4) Shaping

[0099] Place the polypropylene film material 2 that has completed thermal stretching between the first shaping roller 137 with a traveling speed of 4.1 m / min and the second shaping roller 138, and form shaping stretching by using the speed difference. The shaping speed ratio is 0.8. Set the oven temperature to 135 °C to bake and heat the film material 2, and the shaping temperature is 135 °C.

[0100] Table 1

[0101]

[0102] Referring to Table 1, it records the diaphragm preparation process parameters and diaphragm performance parameters of Example 1 and Comparative Examples 1-2. From the above results, it shows that the product treated with laser heating in Example 1 takes into account various physical and chemical characteristics, makes the physical and chemical consistency better, and has a small range. While the products prepared by using steel rollers and oven heating have poor air permeability and thickness consistency, and large thermal shrinkage.

[0103] In the process of dry single-direction stretching to produce film materials of the present utility model, the heating method of the film material in the heat treatment - cold stretching - thermal stretching - shaping process is changed from oil temperature heating inside the roller and oven heating to laser heating. Under the condition of a certain total stretching ratio, through laser heating, the film material is heated more evenly on the roller surface, the lamellar crystal arrangement is more regular in the heat treatment stage, the pore size and distribution are more uniform in the thermal stretching and cold stretching processes, and the internal stress of the film material can be better eliminated in the shaping stage, reducing the differences in various physical and chemical properties caused by uneven heating of the surface film and the inner layer, and improving the charge and discharge performance and energy density of the battery product.

[0104] The above is only an exemplary embodiment of the present utility model, and does not limit the patent scope of the present utility model accordingly. Any equivalent structural transformation made under the technical concept of the present utility model by using the content of the specification and drawings of the present utility model, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present utility model.

Claims

1. A lithium battery diaphragm baking device, characterized in that: include: A transmission mechanism, wherein the transmission mechanism is configured to drive the film material to move; A laser heating component, the position of which corresponds to the transmission mechanism, and the laser heating component is used to heat the film material transmitted by the transmission mechanism.

2. The lithium battery diaphragm baking device according to claim 1, characterized in that: The lithium battery diaphragm baking device also includes a chassis, which is arranged above the transmission mechanism. The chassis has an opening, and the opening is opposite to the transmission mechanism. The number of the laser heating components is multiple groups, and the multiple groups of laser heating components are installed in the chassis at intervals.

3. The lithium battery diaphragm baking device according to claim 2, characterized in that: The plurality of groups of laser heating components include: A heat treatment heating component, a cold drawing heating component, a hot drawing heating component and a shaping heating component are sequentially arranged along a first direction; The heat treatment heating component, the cold drawing heating component, the hot drawing heating component and the shaping heating component are used for temperature control of different processes.

4. The lithium battery diaphragm baking device according to claim 3, characterized in that: The chassis further comprises: a first baffle, a second baffle and a third baffle; The first baffle is disposed between the heat treatment heating assembly and the cold drawing heating assembly; The second baffle is disposed between the cold-drawing heating assembly and the hot-drawing heating assembly; The third baffle is arranged between the hot-drawing heating assembly and the shaping heating assembly.

5. The lithium battery diaphragm baking device according to claim 3, characterized in that: The lithium battery diaphragm baking device also includes: an exhaust component, the exhaust component includes an exhaust fan and an exhaust pipe, a crossbeam is provided in the chassis, the exhaust fan is connected to the crossbeam, an exhaust port is provided in the chassis, one end of the exhaust pipe is connected to the exhaust fan, and the other end of the exhaust pipe is connected to the exhaust port.

6. The lithium battery diaphragm baking device according to claim 1, characterized in that: The laser heating component is arranged on any one side or two opposite sides of the film material.

7. The lithium battery diaphragm baking device according to claim 2, characterized in that: The laser heating component includes a laser source and a laser homogenizer. The laser source is arranged on the chassis. The laser homogenizer is connected to the laser source. The laser emitted by the laser source is homogenized by the laser homogenizer and then irradiated on the film material to uniformly heat the film material.

8. The lithium battery diaphragm baking device according to claim 7, characterized in that: The laser source is a multi-mode laser source.

9. The lithium battery diaphragm baking device according to claim 3, characterized in that: The transmission mechanism comprises: An unwinding assembly, the unwinding assembly is used to unwind the film material; A winding assembly, arranged opposite to the unwinding assembly, for winding the film material; A stretching assembly is arranged between the unwinding assembly and the winding assembly, and is used for performing multi-stage stretching on the film material.

10. The lithium battery diaphragm baking device according to claim 9, characterized in that: The unwinding assembly comprises: An unwinding roller, the unwinding roller is used to unwind the film material; A pressure roller, the pressure roller abuts against the film material and is used to apply pressure to the unrolled film material; The transmission roller is arranged opposite to the unwinding assembly and is used to drive the film material to move along the transmission roller to the winding assembly.

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