Lithium slurry production device and viscosity control method thereof

Abstract

The application discloses the technical field of lithium battery slurry and discloses a lithium battery slurry production device and a viscosity control method thereof. The production device comprises an extrusion cavity, a plurality of screw assemblies are arranged in the extrusion cavity, the screw assemblies are used for mixing lithium battery slurry, the extrusion cavity comprises a material adding area, a first kneading area, a second kneading area and a discharging area in sequence, and the areas are respectively provided with an adding port; a viscosity detector is installed at the discharging port of the extrusion cavity, the viscosity detector is used for detecting the viscosity of the slurry; a liquid inlet device is in communication with the adding port; a driving assembly is connected with the extrusion cavity, and the driving assembly is used for driving the screw assemblies. The lithium battery slurry production device receives the viscosity detector signal through an external controller to obtain real-time viscosity information of the slurry, controls the liquid inlet device to add a corresponding amount of diluent into the extrusion cavity according to the viscosity information, thereby real-time regulating and controlling the viscosity of the slurry in the extrusion cavity, and ensuring the stability of product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery slurry, in particular to a lithium battery slurry production device and a viscosity control method thereof. BACKGROUND

[0002] In the production process of lithium battery cells, the front-end process will adopt the uniform slurry method to stir and mix the powder material and the liquid solvent, and then deliver it to the next coating process for the production of cell pole pieces. At present, most of the uniform slurry processes adopt the traditional process of batch stirring equipment, which has the disadvantages of backward production efficiency, limitation by factory space, and difficulty in uniformly dispersing high solid content electrode slurry, etc., which has become the main bottleneck restricting the progress of lithium battery cell production process.

[0003] At present, the mixing of lithium battery slurry adopts a double screw extruder scheme, which can achieve better uniformity and higher yield compared with other mixing methods. However, due to the relatively long structure of the double screw extruder, the slurry needs to pass through a long distance to achieve the required uniformity effect, and the outlet and inlet are relatively long. Therefore, it is difficult for the above-mentioned slurry to obtain its parameters in real time, especially the uncontrollable viscosity of the slurry. At present, the common way is to first carry out trial production, test the appropriate viscosity, and then carry out batch production.

[0004] However, the raw materials of the slurry are not constant in nature, so it is difficult to avoid the production of slurry that does not meet the requirements during batch production. SUMMARY

[0005] The present application provides a lithium battery slurry production device and a viscosity control method thereof, which solves the problem of difficult control of the viscosity of the slurry in the prior art, realizes the continuous production of lithium battery slurry while controlling the viscosity of the slurry, and ensures the stability of product quality.

[0006] The present application provides a lithium battery slurry production device, which comprises:

[0007] An extrusion cavity is provided with a plurality of screw assemblies, the screw assemblies are used to mix lithium battery slurry, and the extrusion cavity comprises a material adding area, a first kneading area, a second kneading area and a discharging area in sequence, and the first kneading area, the second kneading area and the discharging area are respectively provided with an adding port;

[0008] A viscosity detector is installed at the discharging port of the extrusion cavity, and the viscosity detector is used to detect the viscosity of the slurry;

[0009] A liquid inlet device is provided, and the liquid outlet of the liquid inlet device is communicated with the adding port;

[0010] A driving assembly is connected with the extrusion cavity, and is used to drive the screw assembly.

[0011] In the above embodiment, the material adding area is used to add the solid material mixed with the slurry. Therefore, at the material adding area, the slurry is also in a completely separated state. When gradually running to the first kneading area, a certain amount of diluent is added. The diluent at this position can be used for preliminary kneading of the material, that is, the material at this position has been partially kneaded. When the material gradually runs to the second kneading area, a certain amount of diluent is continuously added. The diluent at this position will make the material be kneaded for the second time. The slurry at this position will become a slurry state. After passing through the second kneading area, the slurry enters the discharging area and is discharged.

[0012] The above embodiment has the beneficial effect that the lithium battery slurry production device obtains real-time viscosity information of the slurry by receiving a signal of a viscosity detector through an external controller, and controls the liquid inlet device to add a corresponding amount of diluent into the extrusion cavity according to the viscosity information, so as to realize real-time regulation and control of the viscosity of the slurry in the extrusion cavity, and ensure the stability of product quality.

[0013] On the basis of the above embodiment, the present application can be further improved, specifically as follows:

[0014] In one of the embodiments of the present application, the extrusion cavity is provided with a first screw assembly and a second screw assembly. A gearbox is connected between the driving assembly and the extrusion cavity. The gearbox is connected with the first screw assembly and the second screw assembly through a shaft coupling. The first screw assembly and the second screw assembly are used to mix the lithium battery slurry.

[0015] In one of the embodiments of the present application, the extrusion cavity is sequentially connected by eleven housings. The material cavity area is arranged at the first housing. The first kneading area is arranged at the second to fourth housings. The second kneading area is arranged at the fifth to ninth housings. The discharging area is arranged at the tenth to eleventh housings. The adding port of the discharging area is arranged at the tenth housing.

[0016] In one of the embodiments of the present application, the extrusion cavity is provided with a discharging device at the end. The discharging device is provided with a discharging cavity. The viscosity detector is a probe type viscosity detector and includes a probe. The probe is arranged in the discharging cavity. In this way, when the slurry reaches the discharging device, the probe can detect the viscosity of the slurry in real time. The detection principle of the viscosity is to convert the vibration value and the set value of the relative slurry into the viscosity value.

[0017] In one of the embodiments of the present application, the discharge cavity is tapered, the larger end of the discharge cavity is in communication with the extrusion cavity, and the smaller end serves as the outlet end. In this way, the slurry can obtain further extrusion pressure during discharge, and the slurry can fill the discharge cavity through the taper of the discharge cavity, so that the probe is always in the slurry and can complete real-time detection of the slurry.

[0018] The present application also provides a viscosity control method for the above lithium battery slurry production device, comprising the following steps:

[0019] S1: introducing material into the extrusion cavity and adding a set amount of diluent, and stirring and mixing;

[0020] S2: obtaining a current viscosity value μ1 by the viscosity detector;

[0021] S3: comparing the current viscosity value μ1 with an expected viscosity value μ0, if | μ1- μ0| is greater than a set value a, then obtaining a diluent addition amount MC according to the current viscosity value μ1, and adding diluent according to the diluent addition amount MC;

[0022] S4: returning to step S2 after a set time delay.

[0023] In one of the embodiments of the present application, in step S3, the diluent addition amount MC is calculated as follows:

[0024] μ1=Kγ n-1 ;

[0025]

[0026] wherein μ1 is the current viscosity obtained by the viscosity detector, γ is the shear rate, K is the rheological coefficient, n is the rheological index, k0 is the fitting coefficient, α, β, θ are the regression coefficients, SME is the mechanical energy during production of the extrusion cavity, MC is the diluent addition amount, T is the temperature of the extruder barrel, SME0, MC0, T0 are the critical values of the mechanical energy, the diluent addition amount, and the barrel temperature, respectively.

[0027] In one of the embodiments of the present application, in step S1, the diluent is added from the addition ports of the first kneading zone, the second kneading zone, and the discharge zone, respectively.

[0028] In one of the embodiments of the present application, the diluent addition amount of the first kneading zone is less than the diluent addition amount of the second kneading zone, and the diluent addition amount of the second kneading zone is less than the diluent addition amount of the discharge zone.

[0029] In one of the embodiments of the present application, in step S3, when adjusting the amount of diluent added, only the amount added in the discharge area is adjusted. That is, the amount of diluent added in the first kneading area and the second kneading area is the original amount, and the amount of diluent added in the discharge area is adjusted according to the viscosity of the current slurry. The reason is as follows: if the amount of diluent added in the first kneading area and the second kneading area is adjusted in real time, the effect of the addition is relatively uncontrollable, and at the same time, it will affect other characteristics of the slurry, such as production temperature, uniformity, etc.; while adjusting the amount of diluent added in the discharge area can achieve better control and will not affect other characteristics of the slurry.

[0030] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0031] 1. The lithium battery slurry production device receives the viscosity detector signal through the external controller to obtain the real-time viscosity information of the slurry, and controls the liquid inlet device to add a corresponding amount of diluent into the extrusion cavity according to the viscosity information, so as to real-time control the viscosity of the slurry in the extrusion cavity, and ensure the stability of the product quality;

[0032] 2. The lithium battery slurry production device is provided with a discharge device, and the discharge cavity in the discharge device is conical, so that the slurry can obtain further extrusion force during discharging, and the slurry can fill the discharge cavity through the neck of the discharge cavity, so that the probe is always in the slurry and can complete the detection of the slurry in real time;

[0033] 3. In the viscosity control method of the lithium battery slurry production device, when adjusting the amount of diluent added, the amount added in the discharge area is adjusted, which can achieve better control and will not affect other characteristics of the slurry. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual proportion.

[0035] Figure 1 It is a perspective structural schematic view of a lithium battery slurry production device in the embodiment;

[0036] Figure 2 It is a sectional view of the connection structure of the gearbox, the shaft coupling and the extrusion cavity in the embodiment;

[0037] Figure 3 It is a structural schematic view of the extrusion cavity in the embodiment;

[0038] Figure 4 It is a sectional view of the discharge device in the embodiment;

[0039] Figure 5 Fig. 1 is a schematic view of a front structure of a discharging device in an embodiment;

[0040] Figure 6 Fig. 2 is a flow chart of a viscosity control method of a lithium slurry production device in an embodiment.

[0041] Wherein, 1. driving assembly, 2. gearbox, 3. coupling, 4. extrusion cavity, 41. first screw assembly, 42. second screw assembly, 43. housing, 44. material cavity area, 45. first kneading area, 46. second kneading area, 47. discharging area, 48. adding port, 5. discharging device, 51. discharging cavity, 6. viscosity detector, 61. probe. DETAILED DESCRIPTION

[0042] The present application will be further illustrated in conjunction with the specific embodiments. It should be understood that these embodiments are only used to explain the present application and not used to limit the scope of the present application. After reading the present application, those skilled in the art can make various modifications to the present application, and all these modifications fall within the scope of the present application defined by the appended claims.

[0043] It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0044] In the description of the present application, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. Unless otherwise explicitly specified and limited, the terms "set", "install", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In the description of the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0046] This application provides a lithium battery slurry production apparatus and its viscosity control method, which solves the problem of difficult viscosity control of slurry in the prior art, and realizes the regulation of slurry viscosity while continuously producing lithium battery slurry, thus ensuring the stability of product quality.

[0047] The technical solution in this application is to solve the above problems, and the overall approach is as follows:

[0048] Example 1:

[0049] like Figures 1-5 As shown, a lithium battery slurry production apparatus includes: a drive assembly 1, a gearbox 2, a coupling 3, an extrusion chamber 4, a discharge device 5, a viscosity meter 6, and a liquid inlet device (not shown in the figure).

[0050] The extrusion chamber 4 is provided with a first screw assembly 41 and a second screw assembly 42. The drive assembly 1 is generally a drive motor, which is connected to the first screw assembly 41 and the second screw assembly 42 through a gearbox 2 and a coupling 3. The first screw assembly 41 and the second screw assembly 42 are used to mix lithium battery slurry. The extrusion chamber is composed of eleven shells 43 connected in sequence. The first shell 43 is the material chamber area 44, the second to fourth shells 43 are the first kneading area 45, the fifth to ninth shells 43 are the second kneading area 46, and the tenth to eleventh shells 43 are the discharge area 47. The first kneading area 45, the second kneading area 46 and the discharge area 47 are respectively provided with an addition port 48. The addition port 48 of the discharge area 47 is located at the tenth shell 43.

[0051] The discharge device 5 is located at the end of the extrusion chamber 4, and a discharge cavity 51 is opened inside the discharge device 5. The viscosity meter 6 is configured as a probe 61 type viscosity meter and includes a probe 61. The probe 61 is set in the discharge cavity 51. The viscosity meter 6 is used to detect the viscosity of the slurry. The liquid outlet of the liquid inlet device is connected to the corresponding addition port 48. The liquid inlet device can be a control pump connected to the diluent storage tank or a liquid addition regulating valve, as long as it can realize the controlled quantitative addition function.

[0052] Furthermore, the discharge chamber 51 is configured as a cone shape, with the larger end of the discharge chamber 51 connected to the extrusion chamber and the smaller end serving as the outlet end.

[0053] Furthermore, the production unit also includes an external controller, which receives information from the viscosity meter 6 and controls the amount of diluent added through each inlet 48 via each liquid inlet device.

[0054] Example 2:

[0055] like Figure 6 As shown, a viscosity control method for the above-mentioned lithium battery slurry production apparatus includes the following steps:

[0056] S1: material is added into the extrusion cavity and a certain amount of diluent is added, and stirring and mixing are carried out.

[0057] The material is added through the material adding area, and after the addition is completed, the first kneading area and the second kneading area add corresponding diluent, and the first screw assembly and the second screw assembly operate to realize stirring and mixing of the slurry.

[0058] S2: the current viscosity value μ1 is obtained by the viscosity detector.

[0059] The current viscosity value is measured by using the crack type online viscosity meter for the material in the discharge cavity.

[0060] S3: compare the current viscosity value μ1 with the expected viscosity value μ0, if |μ1-μ0| is greater than the set value a, then according to the current viscosity value μ1, the diluent addition amount MC is obtained and added into the extrusion cavity.

[0061] If |μ1-μ0| is less than the set value a, then directly enter step S4.

[0062] In step S3, the diluent addition amount MC is calculated as follows: the rheological curve Eq1, Eq2 is measured by using the crack type online viscosity meter;

[0063] μ1=Kγ n-1 Eq1

[0064]

[0065] In Eq1, Eq2, μ1 is the current viscosity obtained by the viscosity detector, γ is the shear rate, K is the rheological coefficient, n is the rheological index (related to the formula, and is known under the condition of determining the formula), wherein K is related to the mechanical energy SME, the barrel temperature T and the diluent solvent addition amount MC; n is related to the formula of the material, wherein the shear rate is a known value; k0 is a fitting coefficient, α, β, θ are regression coefficients, SME is the mechanical energy when the extrusion cavity is produced, T is the temperature of the extrusion cavity barrel, SME0, MC0, T0 are respectively the critical values of the mechanical energy, the diluent addition amount and the barrel temperature, wherein the regression coefficient is known, the mechanical energy value is known, and the temperature is known, so as to calculate the diluent addition amount MC.

[0066] S4: after a certain time delay, return to step S2.

[0067] After a period of time, the adjusted material reaches the discharge cavity, and the current viscosity value is obtained again to adjust the addition amount of the diluent, until the viscosity of the slurry meets the expected viscosity requirement and the viscosity of the slurry is monitored regularly.

[0068] Further, in step S1, the diluent is added from the first kneading zone, the second kneading zone and the discharge zone respectively, and the addition amount of the first kneading zone is less than that of the second kneading zone, and the addition amount of the second kneading zone is less than that of the discharge zone. The sum of the addition amounts of the first kneading zone, the second kneading zone and the discharge zone is equal to the addition amount MC of the diluent.

[0069] Further, in step S3, when adjusting the addition amount of the diluent, the addition amount of the discharge zone is adjusted first. That is, the diluent is added at the original set amount at the first kneading zone and the second kneading zone, and the diluent is added at the discharge zone according to the viscosity of the current slurry.

[0070] Embodiment 3:

[0071] The following is an example of a formula for producing a ternary lithium battery cell slurry.

[0072] Step one: according to the rheological properties of the above formula, a control program is designed for the online viscosity control method for adjusting the discharge viscosity state.

[0073] Step two: the discharge viscosity of the slurry is measured in real time by the online viscosity detection device, and the viscosity signal is fed back to the control program. Under the condition that the mechanical energy and the cavity temperature remain unchanged (stable production), the addition amount of the diluent is adjusted online according to the expected viscosity state (related to the process, used to adjust the discharge viscosity), and the error between the online detection viscosity and the expected viscosity is compared.

[0074] As shown in Table 1, the expected slurry product viscosity is 7000cp, the shear rate and viscosity relationship comparison results and the viscosity error comparison results measured by the online viscometer.

[0075] Table 1 Shear rate and viscosity relationship comparison, viscosity error comparison

[0076]

[0077] If the error is too large, it means that the device parameter setting is wrong or the online viscometer measurement is inaccurate, which needs to be checked before production.

[0078] Step three: the control program will calculate the opening of the liquid addition regulating valve according to the expected viscosity, and then control the addition amount of the dilution solvent. According to the expected viscosity of 7000cp, the control program calculates the addition amount of the dilution solvent according to the specific formula rheological curve shown in Eq1 and Eq2 to control the opening of the regulating valve. The calculation process is as follows:

[0079] In the case of shear rate of 3001 / s, mechanical energy of 28KWh / T and barrel temperature of 302K, the expected viscosity is 7000cp. Through formula Eq3:

[0080]

[0081] It was calculated that the dilution solvent addition amount needed to be adjusted to 0.24, or 24% of the total capacity. The results after adjustment are shown in Table 2.

[0082] Table 2 Dilution solvent addition amount versus corresponding discharge viscosity error

[0083]

[0084] As can be seen, the adjusted slurry measured viscosity is closer to the expected viscosity.

[0085] Although the embodiments of the present application have been shown and described above, it should be understood by those having ordinary skill in the art that such embodiments are exemplary only and are not to be taken as limiting the present application, and that variations, modifications, substitutions and alterations can be made to the embodiments without departing from the spirit of the present application.

Claims

1. A lithium plasma slurry production apparatus, characterized by, The device comprises: an extrusion cavity in which a plurality of screw assemblies for mixing lithium battery paste are arranged, the extrusion cavity sequentially comprises a material adding area, a first kneading area, a second kneading area and a discharging area, the first kneading area, the second kneading area and the discharging area are respectively provided with an adding port, the extrusion cavity is provided with a discharging device at the end, the discharging device is provided with a discharging cavity, the discharging cavity is tapered, the larger end of the discharging cavity is communicated with the extrusion cavity, and the smaller end is used as an outlet end; a viscosity detector which is a probe type viscosity detector and comprises a probe, the viscosity detector is installed on the discharging port of the extrusion cavity, the probe is arranged in the discharging cavity, and the viscosity detector is used to detect the viscosity of the paste; a liquid inlet device, the liquid outlet of the liquid inlet device is communicated with the adding port, and the liquid inlet device is used to add diluent to the first kneading area, the second kneading area and the discharging area respectively, when the adding amount of the diluent is adjusted, the diluent in the first kneading area and the second kneading area is added in a set amount, and the diluent in the discharging area is added according to the viscosity of the current paste; a driving assembly connected with the extrusion cavity, and used to drive the screw assemblies.

2. The lithium plasma slurry production apparatus according to claim 1, characterized by: The extrusion cavity is provided with a first screw assembly and a second screw assembly, a gearbox is connected between the driving assembly and the extrusion cavity, the gearbox is connected with the first screw assembly and the second screw assembly through a shaft coupling, and the first screw assembly and the second screw assembly are used to mix the lithium battery paste.

3. The lithium plasma slurry production apparatus according to claim 1, characterized by: The extrusion cavity is sequentially connected by eleven housings, the material cavity area is arranged at the first housing, the first kneading area is arranged at the second to fourth housings, the second kneading area is arranged at the fifth to ninth housings, and the discharging area is arranged at the tenth to eleventh housings.

4. A viscosity control method of the lithium battery paste production device according to any one of claims 1-3, comprising the following steps: S1: the material is introduced into the extrusion cavity, and a set amount of diluent is added, and stirring and mixing are performed; S2: the current viscosity value μ1 is obtained by the viscosity detector; S3: the current viscosity value μ1 is compared with the expected viscosity value μ0, if | μ1- μ0| is greater than a set value a, the adding amount MC of the diluent is obtained according to the current viscosity value μ1, and the diluent is added according to the adding amount MC of the diluent; S4: after a set time delay, the step S2 is returned.

5. The viscosity control method of claim 4, wherein: In the step S3, the adding amount MC of the diluent is calculated as follows: ； ； wherein μ1 is the current viscosity obtained by the viscosity detector, is the shear rate, is the rheological coefficient, and n is the rheological index, is the fitting coefficient, , , is the regression coefficient, is the mechanical energy during production of the extrusion cavity, MC is the diluent addition amount, is the temperature of the extruder barrel, , , are the critical values of the mechanical energy, the diluent addition amount, and the barrel temperature, respectively.

6. The viscosity control method of claim 4, wherein: In the step S1, the diluent is added from the adding ports of the first kneading area, the second kneading area and the discharging area respectively.

7. The viscosity control method of claim 6, wherein: The adding amount of the diluent in the first kneading area is less than that in the second kneading area, and the adding amount of the diluent in the second kneading area is less than that in the discharging area.

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