Processing device, and method for producing press material for anode material

Abstract

To provide a processing device for identifying a manufacturing condition of an anode material which reduces characteristic fluctuation of a lithium ion battery.SOLUTION: A processing device comprises a memory, which stores a program instruction, and a processor. The program instruction causes the processor, when the program instruction is executed by the processor: to obtain a plurality of candidate values including a target value of a specific surface area of an anode material or a vicinity value in the vicinity of the target value using a first relation which gives the specific surface area of an anode plate by a specific surface area expression comprising a term including a post-press anode material thickness and a pre-press anode material thickness and a primary term of the specific surface area of an anode active material within a first range of the post-press anode material thickness; to identify a single specific value which gives any one of the target value and the vicinity value from the candidate values; and to identify a press condition corresponding to the specific value from a second relation between an anode press condition, which achieves a thickness of the anode material, and the post-press anode thickness. The vicinity value and the target value are settled within a second range narrower than the first range and the range of the specific surface area which is identified by the specific surface area expression.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to processing equipment and methods for making press stock for negative electrode materials. [Background technology]

[0002] Patent Document 1 discloses providing a negative electrode that has low resistance, excellent charge / discharge cycle characteristics under high load, and excellent high-temperature storage durability.

[0003] Patent Document 2 discloses providing an electrode material (composite) that has good ductility and enables the surface area of ​​an electrode active material layer in the coating film stage before drying to be easily increased by press molding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-91793 A [Patent Document 2] JP 2022-115019 A Summary of the Invention [Problem to be solved by the invention]

[0005] The battery life and resistance to lithium deposition of a lithium-ion battery are related to the specific surface area of ​​the negative electrode plate, which is in turn related to the specific surface area of ​​the negative electrode active material and is further related to the negative electrode pressing conditions.

[0006] Patent Documents 1 and 2 do not disclose guidelines for specifying the pressing conditions for producing the negative electrode plate.

[0007] However, since the specific surface area of ​​the negative electrode plate affects the battery life and resistance to lithium deposition of a lithium ion battery, it is possible to specify a specific surface area of ​​the negative electrode plate that provides desired characteristics in these characteristics. On the other hand, the relationship between the specific surface area of ​​the negative electrode plate and the pressing conditions of the negative electrode plate is not clear.

[0008] The present invention aims to provide a processing device configured to specify manufacturing conditions for a negative electrode material that reduces the characteristic fluctuation of lithium ion batteries, and a method for producing a pressed material for a negative electrode material that reduces the characteristic fluctuation of lithium ion batteries. [Means for solving the problem]

[0009] A first aspect of the present invention is a processing device for identifying pressing conditions for a negative electrode material of a lithium ion battery, the processing device comprising at least one memory for storing computer program code, and at least one processor coupled to the memory, the computer program code, when executed by the processor, causing the processor to determine a target value or a previous value of the specific surface area of ​​the negative electrode material using a first relationship that provides a specific surface area of ​​the negative electrode material according to a specific surface area equation that includes at least a term including a thickness of the negative electrode material after pressing and a thickness of the negative electrode material before pressing, and a term including a specific surface area of ​​the negative electrode active material. The method is configured to: obtain a plurality of candidate values ​​including at least one of specific surface area neighboring values ​​near the target specific surface area value in a first range of the negative electrode material post-thickness; identify a single specific value that gives either the target specific surface area value or the specific surface area neighboring value from the candidate values; and identify press conditions corresponding to the specific value from a second relationship between the post-negative electrode material thickness and the negative electrode press conditions that achieve the post-negative electrode material thickness, wherein the specific surface area neighboring value and the target specific surface area value are in a second range narrower than the first range and the range of the specific surface area identified by the specific surface area formula.

[0010] A second aspect of the present invention is a method for producing a pressed material for a negative electrode material of a lithium ion battery, the method comprising: obtaining a plurality of candidate values ​​including a target value of the specific surface area of ​​the negative electrode material or a specific surface area neighboring value near the target value of the specific surface area using a first relationship that gives a specific surface area of ​​the negative electrode material by a specific surface area equation that includes at least a term including a post-press negative electrode material thickness and a term including a specific surface area of ​​a negative electrode active material; identifying a single specific value that gives either the target value of the specific surface area or the specific surface area neighboring value from the candidate values; identifying press conditions corresponding to the specific value from a second relationship between the post-press negative electrode material thickness and negative electrode press conditions that achieve the thickness of the negative electrode material; and pressing the pre-press negative electrode material using the identified press conditions to produce a pressed negative electrode material, the specific surface area neighboring value and the target value of the specific surface area being in a second range narrower than the range of values ​​of the specific surface area identified by the first range. Effect of the Invention

[0011] According to the above aspects, there are provided a processing device configured to specify manufacturing conditions for a negative electrode material that reduces characteristic fluctuations of lithium ion batteries, and a method for producing a pressed material for a negative electrode material that reduces characteristic fluctuations of lithium ion batteries. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating a processing apparatus according to the present embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a relationship in which values ​​in a first range are mapped to respective candidate values ​​in a mapping range according to a first relationship. [Diagram 3] FIG. 3 is a diagram showing an exemplary second relationship for converting a specific value determined by the first relationship into a press condition. [Figure 4] FIG. 4 is a diagram showing a module configuration of the processing apparatus according to the present embodiment. [Diagram 5] FIG. 5 is a block diagram showing the configuration of a processing device according to this embodiment. [Figure 6] FIG. 6 is a diagram showing the main steps of the manufacturing method according to this embodiment. [Figure 7] FIG. 7 is a graph showing the relationship between the specific surface area of ​​the negative electrode material obtained in the production method and the number of negative electrode materials produced. [Figure 8] FIG. 8 is a diagram showing the correlation between the rate of change in negative electrode density and a group of variables other than the rate of change in negative electrode density in the specific surface area of ​​the negative electrode material of the first relationship according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, each embodiment for carrying out the present invention will be described with reference to the drawings. In the following description, the same or similar parts are designated by the same or similar reference numerals, and duplicated description will be omitted.

[0014] FIG. 1 is a diagram illustrating a processing apparatus according to the present embodiment.

[0015] The processing device 11 is configured to identify pressing conditions for anode materials of lithium ion batteries. The processing device 11 includes a processing section 13 and a storage section 15. The processing section 13 includes at least one memory 17 and at least one processor 19. The memory 17 is configured to store computer program code 21. The processing section 13 and the storage section 15 are bidirectionally coupled by a communication line 10b to allow mutual transfer of data.

[0016] The processing device 11 is associated with at least the following processes. These processes may include a material preparation process, a kneading process, a coating process, a press condition specification process, a pressing process, and downstream processes. Specifically, the processing device 11 may receive traceability or tracking information in the production of products from these processes and store the received information. The stored information is provided upon request. The traceability or tracking information may include process information (information 28a, 28b, 28c, 28d, 28e, 28f for each of the above six processes), such as the conditions of the processes performed in each process, the characteristics before the processes, and the characteristics after the processes. The processing device 11 may include a program module configured to perform the processes described subsequently.

[0017] The processing device 11 can be communicatively connected to a manufacturing line 30. The manufacturing line 30 includes several manufacturing sections 23. An exemplary manufacturing section 23 can include a material section 25a, a kneading section 25b, a coating section 25c, a condition specifying section 25d, a press section 25e, and a downstream process section 25f. The material section 25a is configured to perform a material preparation process. The kneading section 25b is configured to perform a kneading process. The coating section 25c is configured to perform a coating process. The condition specifying section 25d is configured to perform a press condition specifying process. The press section 25e is configured to perform a press process. The downstream process section 25f is configured to perform a process subsequent to the press process.

[0018] The material section 25a, the kneading section 25b, the coating section 25c, the condition specification section 25d, the pressing section 25e, and the downstream process section 25f can be bidirectionally coupled to a storage section 15, such as a database, via a communication line 10c. The storage section 15 can receive information on the production information of the negative electrode material (e.g., material information of the negative electrode material, production conditions for kneading, production conditions for coating, thickness of the negative electrode material before pressing, thickness of the negative electrode material after pressing, pressing conditions, specific surface area of ​​the negative electrode active material, tap density, blackness, history related to the specific surface area of ​​the negative electrode material) or can transmit the production information upon request.

[0019] 2 shows a relationship in which values ​​in a first range RNG1 are mapped to candidate values ​​in a mapping range by a first relation 31 according to this embodiment. The first range RNG1 includes, for example, 10 values ​​(a0 to a9). The values ​​(a0 to a9) in the first range RNG1 are mapped to each of the 10 candidate values ​​(b0 to b9) in a mapping range RNG3 by conversion using the first relation 31.

[0020] 1 and 2, the computer program code 21, when executed by the processor 19, is configured to cause the processor 19 to perform, for example, the following process 1, process 2 and process 3. Process 1: Using a first relationship 31 expressed by a specific surface area equation including at least a first term of the specific surface area of ​​the negative electrode active material and a term of the post-press thickness of the negative electrode material, obtain a target value TG (not shown) of the specific surface area of ​​the negative electrode material (specific surface area of ​​the negative electrode material after pressing) or a nearby value NB (not shown) near this target value TG within a first range RNG1 of the post-press thickness of the negative electrode material. Process 2: Identifying a single specific value from the candidate values ​​that provides either the target value TG or the neighborhood value NB. Step 3: Identifying the pressing conditions corresponding to the specific values ​​from the second relationship 33 between the negative electrode pressing conditions for achieving the thickness of the negative electrode material and the post-negative electrode material thickness.

[0021] The processing device 11 can associate a target value TG that provides a good balance between high resistance to lithium precipitation and a capacity retention rate of a battery with the post-press thickness of the negative electrode material. Using this association, it is possible to identify negative electrode press conditions that provide a negative electrode material thickness (a negative electrode material thickness after pressing) that can provide a specific surface area of ​​the negative electrode material (specific surface area of ​​the negative electrode material after pressing) that conforms to the target value TG and the vicinity value NB, based on the relationship between the post-press thickness of the negative electrode material and the negative electrode press conditions.

[0022] Moreover, the computer program code 21, when executed by the processor 19, is configured to cause the processor 19 to perform, for example, the following process 4. Process 4: Receiving a target value TG.

[0023] The exemplary first relationship 31 can be expressed, for example, by the following equation: Specific surface area of ​​negative electrode material = (specific surface area of ​​negative electrode active material) +f1 (thickness of negative electrode material before pressing, thickness of negative electrode material after pressing) +c0 The symbol "f1" represents a function including (thickness of the negative electrode material before pressing) and (thickness of the negative electrode material after pressing) as independent variables. "c0" denotes a constant term that is added when necessary.

[0024] Specifically, when (specific surface area of ​​negative active material), (target value of specific surface area of ​​negative material), and a first range RNG1 (plurality of values ​​within the first range) of the post-negative material thickness (sheet thickness after pressing) are given, candidate values ​​(b0 to b9) of the post-negative material thickness after pressing are obtained based on a first relationship 31, as shown in FIG. 2. The number of candidate values ​​is the same as the number of values ​​within the first range RNG1. The first relationship 31 can be derived by statistically processing values ​​measured in an experiment.

[0025] A single specific value that reduces the difference between the candidate values ​​(b0 to b9) and the target value TG is selected from the candidate values ​​(b0 to b9) in the mapping range RNG3. This specific value can be a value equal to the target value TG or a neighborhood value NB close to the target value TG. A second range RNG2 (not shown) specified by the target value TG and the neighborhood value NB is smaller than the mapping range RNG3. When this specific value is a value equal to the target value TG, the range of the second range RNG2 mathematically includes only a single point.

[0026] In this way, a single specific value is identified from the candidate values. The specific value can be equal to the target value TG or one of the neighboring values ​​NB. Specifically, the neighboring value NB can be identified such that the difference between the specific value and the target value TG is smaller than the maximum value of the difference between the elements in the mapping range RNG3 and the target value TG. One of the neighboring values ​​NB can be, for example, the value closest to the target value TG among the candidate values, and this value can be selected as the specific value.

[0027] The neighborhood value NB and the target value TG are in a second range RNG2 that is narrower than the mapping range RNG3, i.e., the range of specific surface areas, specified by the specific surface area equation of the first relationship 31 and the first range RNG1. Exemplary specific values ​​are selected to minimize the above difference.

[0028] A single specific value, in other words, a post-pressing thickness of the anode material to be achieved, is converted into a pressing condition based on the second relationship 33. The second relationship 33 is specified in association with tracking information of a process prior to the pressing process. Using this pressing condition, anode material (anode plate) is manufactured. The manufactured post-pressing anode material can have a value close to the post-pressing anode material thickness given in the second relationship 33. The second relationship 33 can be derived by statistically processing values ​​measured in an experiment.

[0029] FIG. 3 is a diagram showing an exemplary second relation 33 that converts a specific value specified by the first relation 31 into a press condition. In FIG. 3, the expected specific values ​​are shown as values ​​in a fourth range RNG4 (c0 to c9), and the press conditions are shown as values ​​in a fifth range RNG5 (d0 to d9). The exemplary second relation 33 is expressed in the form of a table, but is not limited thereto. The second relation 33 provides a single corresponding press condition when a specific value is given.

[0030] As previously explained, the target value TG is set to provide a good balance between resistance to lithium precipitation and capacity retention of the battery in the lithium ion battery to be manufactured. A negative electrode material having a thickness associated with the negative electrode material thickness after pressing can be fabricated to achieve the target value TG and a specific surface area therearound or nearby in the lithium ion battery.

[0031] The exemplary first relationship 31 can be expressed, for example, by the following equation:

[0032] A useful first relationship 31 can be provided by replacing function f1 (thickness of negative electrode material before pressing, thickness of negative electrode material after pressing) with (rate of change in density before and after pressing of negative electrode). Specifically, the first relationship 31 can be expressed by, for example, the following equation. Specific surface area of ​​negative electrode material = (specific surface area of ​​negative electrode active material) + (Density change rate before and after pressing the negative electrode) + c0 The specific surface area of ​​the negative active material can be provided by, for example, a manufacturer of the negative active material. Alternatively, a manufacturer of the negative plate may measure the specific surface area of ​​the negative active material on the production line 30. The specific surface area of ​​the negative electrode material is measured for the negative electrode plate after pressing.

[0033] In addition, (the rate of change in density before and after pressing the negative electrode) is replaced with the material thickness ratio between the thickness of the negative electrode material after pressing and the thickness of the negative electrode material before pressing.

[0034] The computer program code 21, when executed by the processor 19, is configured to cause the processor 19 to perform, for example, the following process 5: Step 5: Obtaining the thickness of the negative electrode material before pressing.

[0035] Furthermore, another exemplary first relationship 31 can be expressed, for example, by the following equation: Specific surface area of ​​negative electrode material = (specific surface area of ​​negative electrode active material) + (Density change rate before and after pressing the negative electrode) + c1 × (Tap density) + c0 The tap density can be provided by, for example, the manufacturer of the negative active material obtained. Alternatively, the manufacturer of the negative plate may measure the tap density of the negative active material on the production line 30.

[0036] Furthermore, another exemplary first relationship 31 can be expressed, for example, by the following equation: Specific surface area of ​​negative electrode material = (specific surface area of ​​negative electrode active material) + (Density change rate before and after pressing the negative electrode) + c2 × (blackness) + c0 The blackness can be measured, for example, during the kneading process (described later). The measurement of the blackness provides information about the peeling of the active material coating after the powder is made into a paste.

[0037] Furthermore, another exemplary first relationship 31 can be expressed, for example, by the following equation: Specific surface area of ​​negative electrode material = (specific surface area of ​​negative electrode active material) + (Density change rate before and after pressing the negative electrode) + c1 × (tap density) +c2×(blackness)+c0

[0038] These exemplary first relationships 31 can be generated by a regression analysis between the specific surface area of ​​the negative electrode material and the specific surface area, negative electrode material thickness ratio, tap density, and blackness of the negative electrode active material.

[0039] The computer program code 21, when executed by the processor 19, is arranged to cause, for example, the following process 6 to occur: Step 6: Conduct a regression analysis to obtain a first relationship 31 of any one of the above. Tracking information from a running manufacturing line 30 can be used as data for the regression analysis.

[0040] In the exemplary processing device 11, obtaining candidate values ​​in the first range RNG1 of post-negative electrode material thickness can be achieved by at least one of calculating the first relationship 31 by the processor 19 and searching a table representing the first relationship 31 by the processor 19.

[0041] Moreover, the computer program code 21, when executed by the processor 19, is configured to cause the processor 19 to perform, for example, the following process 7: Process 7: Configured to create a table showing the first relationship 31. The specific surface area table can be created, for example, by calculation using the specific surface area formula of the negative electrode material.

[0042] As already described, the second relationship 33 can be determined by experiment, and specifically, can be expressed in the form of a table, an approximate formula, etc. The approximate formula can be determined, for example, by performing a regression analysis using multiple values ​​of the negative electrode material thickness after pressing and multiple values ​​of the negative electrode material thickness before pressing.

[0043] 4 is a diagram showing a module configuration of a processing device according to this embodiment. The processing device 11 can include modules 221, 222, 223, 224, 225, 226, and 227. The modules 221, 222, 223, 224, 225, 226, and 227 are configured to perform processes 1, 2, 3, 4, 5, 6, and 7, respectively.

[0044] FIG. 5 is a block diagram showing the configuration of the processing device according to the present embodiment. An exemplary computer 20 for the processing device 11 may include a central processing unit (CPU) 41, a memory 42, an input / output port 43, and a network port 44, and may include an input device 45 and a display 46, if necessary. The memory 42 is communicatively coupled to the central processing unit 41. The input / output port 43 is communicatively coupled to the central processing unit 41, and receives data from an external sensor and transmits the received data. The network port 44 is communicatively coupled to the central processing unit 41 and is connected to an (external) network. The input device 45 is communicatively coupled to the central processing unit 41. The display 46 is communicatively coupled to the central processing unit 41 and the memory 42. Program instructions that cause the processing device 11 to perform a desired operation are stored in the memory 42 or are provided from a network via the network port 44. The program instructions are executed by the central processing unit 41 to cause the processing device 11 to perform a desired operation.

[0045] 6 is a diagram showing the main steps of the manufacturing method according to the present embodiment. The manufacturing method 100 may include the following main steps: A method for manufacturing a pressed material for a negative electrode of a lithium ion battery will be described.

[0046] Material preparation process S101 A negative electrode current collector 63 is prepared. Also, materials 61 for the negative electrode paste are prepared, specifically, a negative electrode active material containing graphite, a binder, a thickener, and a solvent. Tracking information for these materials, such as lot numbers, amounts used, and the date and time of use, are recorded.

[0047] As an exemplary negative electrode active material, an amorphous coated graphite powder in which natural graphite powder is coated with amorphous carbon, or natural graphite powder is prepared. As an exemplary binder, for example, styrene butadiene rubber (SBR) is prepared. As an exemplary thickener, for example, carboxymethyl cellulose (CMC) is prepared. As an exemplary solvent, for example, pure water is prepared. As an exemplary negative electrode current collector 63, for example, a metal foil containing copper, nickel, or an alloy thereof is prepared. The metal foil can be a rolled metal thin film.

[0048] During the preparation of the materials, tracking information such as provided or measured tap density values ​​and specific surface areas of the negative electrode active materials can be recorded.

[0049] Kneading process S102 The negative electrode paste 65 is prepared by kneading the negative electrode active material in the solvent. In preparing the negative electrode paste 65, a material 67 is prepared that includes a binder, a thickener, and a solvent in addition to the negative electrode active material. Each of the negative electrode active material, the binder, the thickener, and the solvent is weighed. These values ​​are recorded as tracking information of the materials used to prepare the negative electrode paste 65. The mixture of the binder, the thickener, and the solvent in addition to the negative electrode active material is kneaded to obtain the negative electrode paste 65.

[0050] During the preparation of the paste by kneading, tracking information such as the blackness of the negative electrode active material is recorded. This value is recorded as tracking information. The blackness can be measured optically.

[0051] Coating process S103 A negative electrode active material layer 71 is formed on the negative electrode current collector 63 to produce a negative electrode sheet 69. Specifically, the negative electrode active material layer 71 is formed by applying a negative electrode paste 65 (negative electrode mixture) containing a negative electrode active material to the negative electrode current collector 63. The negative electrode paste 65 can be applied to one or both sides of the negative electrode current collector 63. The applied negative electrode paste is dried on the negative electrode current collector 63 to produce a negative electrode sheet 69 (negative electrode material). The application can be performed using a coater.

[0052] During coating, the thickness T1 of the negative electrode sheet 69 including the dried negative electrode active material layer 71 is measured. This thickness is recorded as tracking information.

[0053] Step S104 of specifying press conditions The thickness for the pressing condition of the negative electrode sheet 69 is obtained from the exemplary specific formula shown below. This thickness can be used as the target value for the pressed negative electrode sheet 69 (pressed negative electrode material).

[0054] An exemplary specification is given as a linear sum as follows: Specific surface area of ​​negative electrode material = (specific surface area of ​​negative electrode active material) +3.261 x (density change rate before and after pressing the negative electrode) -1.594×(tap density) -0.0992×(blackness) -1.6917

[0055] The coefficients in this formula, specifically, "3.261", "-1.594", "-0.0992", and "-1.6917", are exemplary values ​​and are identified for each type of negative electrode to be fabricated by the methods already described (e.g., regression analysis).

[0056] The density change rate before and after pressing the negative electrode material can be interpreted as, for example, (thickness T1 of the negative electrode material (composite material) before pressing) / (thickness T3 of the negative electrode material (composite material) after pressing). The specific surface area of ​​the negative electrode material is the target value TG already explained. The search range for the thickness of the negative electrode material after pressing the negative electrode is given as a plurality of values ​​within the first range RNG1. A value (thickness of the negative electrode material after pressing the negative electrode) that reduces the difference between the target value TG and a plurality of candidate values ​​from the plurality of values ​​within the first range RNG1 is selected as the specific value (T0) in the first range RNG1. The specific value (T0) is an input value used for the second relationship 33.

[0057] Specifically, the target thickness for the pressed negative electrode sheet (pressed negative electrode material) is derived as follows: A first range RNG1 (search range) for searching the target thickness for the pressed negative electrode sheet is retrieved from the memory 17 of the processing device 11. In addition, tracking information recorded for each type of negative electrode, such as tap density, blackness, negative electrode material thickness T1 before pressing including the dried negative electrode active material layer 71, and specific surface area of ​​the negative electrode material (target value TG) are retrieved from the storage section 15 or memory 17 of the processing device 11. The retrieved values ​​and the search range value are applied to a specific equation representing the first relationship 31, and multiple candidate values ​​(specific surface area of ​​the negative electrode material) are provided within the search range as multiple target thicknesses for the pressed negative electrode sheet (pressed negative electrode material).

[0058] From these candidate values, a single specific value (T0) that gives a value equal to the specific surface area of ​​the negative electrode material (target value TG) or a value close to the target value TG (neighborhood value NB) is identified. Specifically, the specific value (T0) is provided as a value within a first range RNG1 that gives the candidate value the target value TG or the neighboring value NB. The specific value (T0) may be, for example, equal to the target value of the specific surface area of ​​the negative electrode material, or may be a neighboring value of the specific surface area that is closest to the target value. The single specific value (T0) may be identified using, for example, a grid search, Bayesian optimization, or a genetic algorithm, but is not limited thereto.

[0059] This specific value (T0) is converted, based on the second relationship 33, into a negative electrode pressing condition (PRS) for pressing the pre-press negative electrode material (thickness T1) including the dried negative electrode active material layer 71 to produce a negative electrode sheet 75 (pressed negative electrode material).

[0060] Press process S105 The negative electrode sheet 69 is pressed using the resulting press conditions (PRS) to produce a pressed negative electrode sheet 75 (pressed negative electrode material). An exemplary resulting press condition can be a press gap of rollers 77. A measurement of the thickness of the pressed negative electrode sheet 75 can be a thickness T3, which can be at or near a specific value (T0).

[0061] According to the method 100 for producing a negative electrode of a lithium ion battery and the processing device 11, a target value TG that provides a good balance between high resistance to lithium precipitation and a capacity retention rate of a battery can be associated with the post-press thickness of the negative electrode material. Using this association, it is possible to specify the negative electrode pressing conditions (PRS) that provide a negative electrode material thickness (a negative electrode material thickness after pressing) that can provide a specific surface area of ​​the negative electrode material according to the target value (specific value (T0)) of the thickness of the negative electrode material after pressing, based on the relationship between the negative electrode pressing conditions (PRS) and the target value.

[0062] FIG. 7 is a diagram showing the relationship between the specific surface area of ​​the negative electrode material obtained in the manufacturing method and the number of negative electrode materials produced. The horizontal axis shows the specific surface area of ​​the negative electrode material, and the vertical axis shows the ratio of the number of negative electrode materials produced. In FIG. 7, distribution 81d shows the ratio of the number of negative electrode materials produced using the first relationship 31 and the second relationship 33 according to the present embodiment to the specific surface area of ​​the negative electrode material. Distribution 83d shows the number of negative electrode materials produced without using the first relationship 31 and the second relationship 33 according to the present embodiment to the specific surface area of ​​the negative electrode material. The width of distribution 81d is smaller than the width of distribution 83d.

[0063] FIG. 8 shows the correlation between the negative electrode density change rate and the sum of a group of variables other than the negative electrode density change rate in the specific surface area of ​​the negative electrode material of the first relationship 31 according to this embodiment. The horizontal axis shows the sum of a group of variables other than the negative electrode density change rate, and the vertical axis shows the negative electrode density change rate. Distribution 81c shows the correlation in the negative electrode material manufactured using the first relationship 31 and the second relationship 33 according to this embodiment. Distribution 83c shows the correlation in the negative electrode material manufactured without using the first relationship 31 and the second relationship 33 according to this embodiment. Referring to FIG. 8, when the negative electrode density change rate (relative value) is greater than zero, the main distribution of distribution 81c is in the range of the sum of the other group of variables less than zero. Also, when the negative electrode density change rate (relative value) is less than zero, the main distribution of distribution 81c is in the range of the sum of the other group of variables greater than zero. When the negative electrode density change rate (relative value) is near zero, the main distribution of distribution 81c is near zero in the sum of the other group of variables. Distribution 83c is distributed around the vicinity of zero for the negative electrode density change rate (relative value) and the vicinity of zero for the sum of the other group of variables.

[0064] Derivation of specific formula In a manufacturing line for negative electrodes for lithium ion batteries, a certain type of negative electrode is manufactured while monitoring several parameters, exemplary parameters in this embodiment, such as the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the thickness of the negative electrode material before the negative electrode is pressed, and the thickness of the negative electrode material after the negative electrode is pressed. A lithium ion battery is manufactured using the manufactured negative electrode. Exemplary parameters can further include at least one of tap density and blackness. The characteristics of each manufactured lithium ion battery, specifically, the resistance to lithium precipitation (lithium precipitation resistance characteristic) and the capacity retention rate characteristic (battery life characteristic) of the lithium ion battery are measured. Based on these measured values, the specific surface area of ​​the negative electrode material after pressing that can achieve both the resistance to lithium precipitation and the capacity retention rate to the possible extent is specified. This specific surface area is stored as tracking information of the specific surface area target value for each negative electrode material for lithium ion batteries.

[0065] The relationship between the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the thickness of the negative electrode material before the negative electrode press, and the thickness of the negative electrode material after the negative electrode press can be derived by regression analysis. Also, the relationship between the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the thickness of the negative electrode material before the negative electrode press, the thickness of the negative electrode material after the negative electrode press, and the tap density can be derived by regression analysis. Furthermore, the relationship between the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the thickness of the negative electrode material before the negative electrode press, the thickness of the negative electrode material after the negative electrode press, the tap density, and the blackness can be derived by regression analysis. Furthermore, the relationship between the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the thickness of the negative electrode material before the negative electrode press, the thickness of the negative electrode material after the negative electrode press, the tap density, and the blackness can be derived by regression analysis.

[0066] As the regression analysis, for example, multiple regression analysis can be used.

[0067] The capacity retention rate and resistance to Li deposition of lithium-ion batteries vary depending on the specific surface area of ​​the negative electrode material. The specific surface area of ​​the negative electrode material also varies depending on the specific surface area of ​​the negative electrode active material. Furthermore, the specific surface area of ​​the negative electrode material also varies depending on the negative electrode pressing conditions.

[0068] However, according to the present embodiment, the negative electrode pressing conditions are guided toward the target value of the specific surface area of ​​the negative electrode material via the density change rate before and after the negative electrode pressing, which allows the negative electrode material to be produced with a specific surface area close to the target value and with a small variation in the specific surface area of ​​the negative electrode material produced.

[0069] In addition, according to the present embodiment, the negative electrode pressing conditions are guided toward a target value of the specific surface area of ​​the negative electrode material via the specific surface area of ​​the negative electrode active material, the density change rate before and after the negative electrode pressing, and the tap density. By using these negative electrode pressing conditions, the variation in the specific surface area of ​​the negative electrode material can be reduced.

[0070] Furthermore, according to the present embodiment, the negative electrode pressing conditions are guided toward the target value of the specific surface area of ​​the negative electrode material via the specific surface area of ​​the negative electrode active material, the density change rate before and after the negative electrode pressing, and the blackness. By using these negative electrode pressing conditions, the variation in the specific surface area of ​​the negative electrode material can be reduced.

[0071] The formula relates the traceability information from the upstream and downstream processes in the manufacture of the anode material to the specific surface area of ​​the pressed anode material. The formula shown is an example, and other formulas relating the specific surface area of ​​the anode material to the traceability information from the upstream processes can be derived based on the disclosure of the present embodiment.

[0072] In manufacturing the negative electrode material, a target specific surface area of ​​the pressed negative electrode material is specified that provides a good balance between the product life of the lithium ion battery and the resistance to lithium precipitation. A first relationship 31 relates the target value of the specific surface area of ​​the negative electrode plate to the thickness of the pressed negative electrode material. A second relationship 33 then relates the thickness of the pressed negative electrode material to the pressing conditions. These make it possible to control the specific surface area of ​​the pressed negative electrode material. That is, as shown in FIG. 7, in manufacturing the negative electrode material, the variation in the characteristics related to the product life of the lithium ion battery and the resistance to lithium precipitation can be reduced.

[0073] According to this embodiment, a processing device 11 is provided that is configured to identify manufacturing conditions for a negative electrode material that reduces the characteristic variation of a lithium ion battery, and a method 100 is provided for producing a press material for a negative electrode material that reduces the characteristic variation of a lithium ion battery.

[0074] The present embodiment has various aspects as described below.

[0075] A first aspect of the present embodiment is a processing device for identifying pressing conditions for a negative electrode material of a lithium ion battery, the processing device comprising at least one memory for storing computer program code, and at least one processor coupled to the memory, the computer program code, when executed by the processor, causing the processor to determine a target value or a target value of the specific surface area of ​​the negative electrode material using a first relationship that gives a specific surface area of ​​the negative electrode material according to a specific surface area equation that includes at least a term including a thickness of the negative electrode material after pressing and a thickness of the negative electrode material before pressing, and a term including a specific surface area of ​​the negative electrode active material. obtain a plurality of candidate values ​​in a first range of the negative electrode material post-thickness including at least one of specific surface area neighboring values ​​near the target specific surface area value; identify a single specific value that gives either the target specific surface area value or the specific surface area neighboring value from the candidate values; and identify press conditions corresponding to the specific value from a second relationship between the negative electrode material post-thickness and the negative electrode press conditions that achieve the post-negative electrode material post-thickness, wherein the specific surface area neighboring value and the target specific surface area value are in a second range narrower than the first range and the range of the specific surface area identified by the specific surface area formula.

[0076] In a second aspect according to the first aspect of this embodiment, the specific surface area formula can further include at least a first order term of tap density.

[0077] In a third aspect according to the first or second aspect of this embodiment, the specific surface area formula may further include at least a first order term of blackness.

[0078] In a fourth aspect according to any one of the first to third aspects according to this embodiment, the specific surface area formula includes a linear sum of a first-order term of a specific surface area of ​​the negative electrode active material, a term of a negative electrode material thickness ratio between the thickness after pressing of the negative electrode material and the thickness of the negative electrode material before pressing, a term of a tap density, and a term of blackness, and the specific surface area formula can be generated by a regression analysis of the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the negative electrode material thickness ratio, the tap density, and the blackness.

[0079] In a fifth aspect according to any one of the first to fourth aspects of this embodiment, obtaining a plurality of candidate values ​​in a first range of the post-negative-electrode-material thickness can be at least one of obtaining a specific surface area by calculating the specific surface area formula by the processor, and searching a table expressing a relationship of the specific surface area formula by the processor.

[0080] A sixth aspect of the present embodiment is a method for producing a pressed material for a negative electrode material of a lithium ion battery, the method comprising: obtaining a plurality of candidate values ​​including a target value of the specific surface area of ​​the negative electrode material or a specific surface area neighboring value near the target value of the specific surface area using a first relationship that gives a specific surface area of ​​the negative electrode material by a specific surface area equation having at least a term including a post-press negative electrode material thickness and a term including a specific surface area of ​​a negative electrode active material; identifying a single specific value that gives either the target value of the specific surface area or the specific surface area neighboring value from the candidate values; identifying press conditions corresponding to the specific value from a second relationship between the post-press negative electrode material thickness and negative electrode press conditions that achieve the thickness of the negative electrode material; and pressing the pre-press negative electrode material using the identified press conditions to produce a pressed negative electrode material, wherein the specific surface area neighboring value and the target value of the specific surface area are in a second range narrower than the range of values ​​of the specific surface area identified by the first range.

[0081] In a seventh aspect according to the sixth aspect of this embodiment, the specific surface area formula includes a linear sum of a term for the specific surface area of ​​the negative electrode active material, a term for a negative electrode material thickness ratio between the thickness of the negative electrode material after pressing and the thickness of the negative electrode material before pressing, a term for tap density, and a term for blackness, and the specific surface area formula can be obtained by regression analysis of the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the negative electrode material thickness ratio, the tap density, and the blackness.

[0082] An eighth aspect according to the sixth aspect or the seventh aspect of this embodiment can further include obtaining a relationship between the negative electrode material thickness before pressing and negative electrode pressing conditions that achieve the negative electrode material post-pressing thickness after pressing.

[0083] In a ninth aspect according to any one of the sixth to eighth aspects according to this embodiment, the specific surface area formula includes a linear sum of a term for the specific surface area of ​​the negative electrode active material, a term for a negative electrode material thickness ratio between the thickness after the negative electrode material and the thickness of the negative electrode material before pressing, a term for a tap density, and a term for a blackness, and the method can further include, in producing a plurality of negative electrode materials, obtaining first data on the specific surface area of ​​each of the negative electrode materials using the specific surface area of ​​the negative electrode active material in each of the negative electrode materials, the thickness after the negative electrode material, the thickness of the negative electrode material before pressing, the tap density, and the blackness, obtaining second data on lithium precipitation resistance characteristics and battery life characteristics of each lithium ion battery produced using the negative electrode materials, and specifying the specific surface area target value based on the first data and the second data.

[0084] A tenth aspect according to any one of the sixth to ninth aspects of the present embodiment can further include preparing a material for a negative electrode paste including a negative electrode current collector and a negative electrode active material, producing a negative electrode paste including the negative electrode active material, and applying the negative electrode paste onto the negative electrode current collector to produce a pre-press negative electrode material.

[0085] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention, all of which are included in the technical concept of the present invention. [Explanation of symbols]

[0086] 10b, 10c...communication line, 11...processing device, 13...processing section, 15...storage section, 17...memory, 19...processor, 20...computer, 21...computer program code, 23...manufacturing section, 25a...material section, 25b...mixing section, 25c...coating section, 25d...conditioning section, 25e...press section, 25f...downstream process section, 30...production line, 31... ·First relation, 33···Second relation, 41···Central processing unit, 42···Memory, 43···Input / output port, 44···Network port, 45···Input device, 46···Display, 61···Material, 63···Negative electrode current collector, 65···Negative electrode paste, 67···Material, 69···Negative electrode sheet before pressing, 71···Negative electrode active material layer, 75···Negative electrode sheet after pressing, 77···Roller, 81c, 81d, 83c, 83d···Distribution, 100···Method, 100···Preparation method.

Claims

1. A processing device for determining pressing conditions for a negative electrode material of a lithium ion battery, comprising: at least one memory for storing computer program code; at least one processor coupled to the memory; Equipped with The computer program code, when executed by the processor, causes the processor to: obtaining a plurality of candidate values ​​including at least one of a target value of the specific surface area of ​​the negative electrode material or a specific surface area vicinity value near the target value of the specific surface area, within a first range of the thickness after pressing of the negative electrode material, using a first relationship that gives a specific surface area of ​​the negative electrode material by a specific surface area equation having a term including at least a post-press thickness of the negative electrode material and a term including a specific surface area of ​​the negative electrode active material; Identifying a single specific value that gives either the specific surface area target value or the specific surface area vicinity value from the candidate values; Identifying a pressing condition corresponding to the specific value from a second relationship between the post-negative electrode material thickness and a negative electrode pressing condition that achieves the post-negative electrode material thickness; [0023] The method is configured to: the specific surface area vicinity value and the specific surface area target value are in a second range which is narrower than the first range and the range of the specific surface area specified by the specific surface area formula; Processing unit.

2. The specific surface area formula further includes at least a first-order term of the tap density.

2. The processing device according to claim 1.

3. The specific surface area formula further includes at least a first-order term of blackness; 2. The processing device according to claim 1.

4. The specific surface area formula includes a linear sum of a first-order term of the specific surface area of ​​the negative electrode active material, a term of a negative electrode material thickness ratio between the thickness of the negative electrode material after pressing and the thickness of the negative electrode material before pressing, a term of tap density, and a term of blackness, The specific surface area formula is generated by a regression analysis of the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the negative electrode material thickness ratio, the tap density, and the blackness.

2. The processing device according to claim 1.

5. Obtaining a plurality of candidate values ​​in the first range of the post-negative electrode material thickness is at least one of obtaining a specific surface area by calculating the specific surface area formula by the processor, and searching a table expressing the relationship of the specific surface area formula by the processor.

2. The processing device according to claim 1.

6. A method for making a press material for a negative electrode material of a lithium ion battery, comprising the steps of: obtaining a plurality of candidate values ​​including a target value of the specific surface area of ​​the negative electrode material or a specific surface area vicinity value near the target value of the specific surface area in a first range of the thickness after the negative electrode material using a first relationship that gives a specific surface area of ​​the negative electrode material by a specific surface area equation having a term including at least a post-press thickness of the negative electrode material and a term including a specific surface area of ​​the negative electrode active material; Identifying a single specific value that gives either the specific surface area target value or the specific surface area vicinity value from the candidate values; Identifying a pressing condition corresponding to the specific value from a second relationship between the post-thickness of the negative electrode material and a negative electrode pressing condition that achieves the thickness of the negative electrode material; and Pressing the unpressed negative electrode material using the specified pressing conditions to produce a pressed negative electrode material; Equipped with the specific surface area vicinity value and the specific surface area target value are in a second range narrower than the range of specific surface area values ​​specified by the first range; method.

7. The specific surface area formula includes a term for the specific surface area of ​​the negative electrode active material, a term for a negative electrode material thickness ratio between the thickness of the negative electrode material after pressing and the thickness of the negative electrode material before pressing, a term for tap density, and a term for blackness, The specific surface area formula is obtained by a regression analysis of the specific surface area of ​​the negative electrode material, the specific surface area of ​​the negative electrode active material, the negative electrode material thickness ratio, the tap density, and the blackness.

7. The method of claim 6.

8. 7. The method of claim 6, further comprising obtaining a relationship between the anode material thickness before pressing and anode pressing conditions that achieve the anode material post-pressing thickness.

9. The specific surface area formula includes a term for the specific surface area of ​​the negative electrode active material, a term for a negative electrode material thickness ratio between the thickness of the negative electrode material after pressing and the thickness of the negative electrode material before pressing, a term for tap density, and a term for blackness, The method includes, in producing a plurality of negative electrode materials, obtaining first data regarding the specific surface area of ​​each of the negative electrode materials using a specific surface area of ​​the negative electrode active material in each of the negative electrode materials, the thickness after pressing of the negative electrode material, the thickness of the negative electrode material before pressing, the tap density, and the blackness; Obtaining second data regarding lithium precipitation resistance characteristics and battery life characteristics in each lithium ion battery produced using the negative electrode material; Identifying the specific surface area target value based on the first data and the second data; Further comprising:

7. The method of claim 6.

10. Preparing a material for a negative electrode paste including a negative electrode current collector and a negative electrode active material; Producing a negative electrode paste containing a negative electrode active material; Coating the negative electrode paste on the negative electrode current collector to prepare a negative electrode material before pressing; Further comprising:

10. The method of claim 9.

Images