Method for manufacturing electrode plate for non-aqueous secondary battery and method for manufacturing non-aqueous secondary battery

Abstract

To provide a method of manufacturing an electrode plate for a nonaqueous secondary battery and a method of manufacturing a nonaqueous secondary battery, which are capable of improving the characteristics of a nonaqueous secondary battery.SOLUTION: A method of manufacturing an electrode plate for a nonaqueous secondary battery includes: a specific surface area acquisition step of acquiring the specific surface area of a negative electrode plate with respect to a type of an additive and an added amount of the additive; a reaction area acquisition step of acquiring the reaction area of the electrode plate for a nonaqueous secondary battery with respect to the specific surface area of the negative electrode plate when the type of the additive and the added amount of the additive change; and a target specific surface area acquisition step of acquiring the target specific surface area of the negative electrode plate with respect to the reaction area of the electrode plate for a nonaqueous secondary battery.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an electrode plate for a non-aqueous secondary battery and a method for manufacturing a non-aqueous secondary battery, and more particularly to a method for manufacturing an electrode plate for a non-aqueous secondary battery and a method for manufacturing a non-aqueous secondary battery that can improve the characteristics of the non-aqueous secondary battery. [Background technology]

[0002] Conventionally, non-aqueous secondary batteries include an electrode assembly having a negative electrode plate, a positive electrode plate, and a separator. Such an electrode assembly is housed in a battery case, with the negative electrode plate, the positive electrode plate, and the separator stacked in a stacking direction, together with a non-aqueous electrolyte. Each electrode plate has an electrode mixture layer formed on an electrode substrate, and the electrode mixture layer contains at least an active material and an additive, such as a binder. When manufactured as an electrode plate, the specific surface area of ​​the electrode plate affects the characteristics of the non-aqueous secondary battery, such as the capacity of the non-aqueous secondary battery.

[0003] As a method for manufacturing such a nonaqueous secondary battery, for example, Patent Document 1 discloses a configuration in which the specific surface area of ​​the negative electrode plate is controlled by adjusting the pressing pressure applied to the negative electrode plate in a pressing process. In this way, the characteristics of the nonaqueous secondary battery can be controlled by controlling the specific surface area of ​​the negative electrode plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-116604 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the invention described in Patent Document 1, it is desired to improve the characteristics of non-aqueous secondary batteries by increasing the manufacturing precision of electrode plates for non-aqueous secondary batteries based on the specific surface area of ​​the electrode plates. [Means for solving the problem]

[0006] Various aspects of a method for manufacturing an electrode plate for a non-aqueous secondary battery that solves the above problems will be described. [Aspect 1] A method for manufacturing an electrode plate for a non-aqueous secondary battery, comprising an electrode base material and an electrode mixture layer containing at least an active material and an additive, the method comprising: an additive amount obtaining step for obtaining an additive amount; a specific surface area obtaining step for obtaining a specific surface area of ​​the electrode plate for the type of additive and the additive amount; a reaction area obtaining step for obtaining a reaction area of ​​the electrode plate for the specific surface area of ​​the electrode plate for the non-aqueous secondary battery when the type of additive and the additive amount are changed; and a target specific surface area obtaining step for obtaining a target specific surface area of ​​the electrode plate for the reaction area of ​​the electrode plate for the non-aqueous secondary battery.

[0007] According to the above configuration, it is possible to obtain a target specific surface area of ​​the electrode plate for a non-aqueous secondary battery according to the type and amount of additive. This allows the reaction area of ​​the electrode plate for a non-aqueous secondary battery to be adjusted to a suitable reaction area in design even when at least one of the type and amount of additive changes. Therefore, by improving the manufacturing precision of the electrode plate for a non-aqueous secondary battery, it is possible to suppress a decrease in capacity of the non-aqueous secondary battery and improve the characteristics of the non-aqueous secondary battery.

[0008] [Aspect 2] In the method for manufacturing a non-aqueous secondary battery electrode plate according to [Aspect 1], the addition amount obtaining step obtains an addition amount of a first additive and an addition amount of a second additive as the addition amounts of the additives; the specific surface area obtaining step obtains a specific surface area of ​​the non-aqueous secondary battery electrode plate for the addition amount of the first additive and a specific surface area of ​​the non-aqueous secondary battery electrode plate for the addition amount of the second additive; the reaction area obtaining step obtains a reaction area of ​​the non-aqueous secondary battery electrode plate for its specific surface area based on the addition amount of the first additive and a reaction area of ​​the non-aqueous secondary battery electrode plate for its specific surface area based on the addition amount of the second additive; and the target specific surface area obtaining step obtains a target specific surface area of ​​the non-aqueous secondary battery electrode plate for the reaction area of ​​the non-aqueous secondary battery electrode plate based on the addition amount of the first additive and the reaction area of ​​the non-aqueous secondary battery electrode plate for its specific surface area based on the addition amount of the second additive.

[0009] According to the above configuration, even when a first additive and a second additive are added as additives, a target specific surface area of ​​the electrode plate for a non-aqueous secondary battery can be obtained based on the reaction area of ​​the electrode plate for a non-aqueous secondary battery relative to the amount of the first additive added and the reaction area of ​​the electrode plate for a non-aqueous secondary battery relative to the amount of the second additive added. This allows the reaction area of ​​the electrode plate for a non-aqueous secondary battery to be adjusted to a suitable reaction area for the design, even when the combination of additives added changes. Therefore, by improving the manufacturing accuracy of the electrode plate for a non-aqueous secondary battery based on the specific surface area of ​​the electrode plate for a non-aqueous secondary battery, it is possible to suppress a decrease in capacity of the non-aqueous secondary battery and improve the characteristics of the non-aqueous secondary battery.

[0010] [Aspect 3] In the method for manufacturing an electrode plate for a non-aqueous secondary battery according to [Aspect 1] or [Aspect 2], the additive includes at least one of a binder and a thickener.

[0011] [Aspect 4] A method for producing an electrode plate for a non-aqueous secondary battery, any one of [Aspect 1] to [Aspect 3], including a pressing step of pressing the electrode mixture layer on the electrode base material, wherein the target specific surface area acquisition step acquires a target specific surface area of ​​the electrode plate for a non-aqueous secondary battery in the pressing step according to a reaction area of ​​the electrode plate for a non-aqueous secondary battery, and the pressing step presses the electrode mixture layer on the electrode base material based on the target specific surface area of ​​the electrode plate for a non-aqueous secondary battery.

[0012] According to the above configuration, the specific surface area of ​​the non-aqueous secondary battery electrode plate can be adjusted to a target specific surface area in the pressing step, thereby adjusting the reaction area of ​​the non-aqueous secondary battery electrode plate. Furthermore, the reaction area of ​​the non-aqueous secondary battery electrode plate after completion of the pressing step is the reaction area of ​​the non-aqueous secondary battery electrode plate after production of the non-aqueous secondary battery electrode plate, and the reaction area of ​​the non-aqueous secondary battery electrode plate after production can be adjusted in the pressing step.

[0013] Various aspects of the method for manufacturing a nonaqueous secondary battery that solves the above problems will be described. [Aspect 5] A method for manufacturing a nonaqueous secondary battery including an electrode plate having an electrode base material and an electrode mixture layer containing at least an active material and an additive, the method comprising: an additive amount acquisition step for acquiring an additive amount; a specific surface area acquisition step for acquiring the specific surface area of ​​the electrode plate relative to the type of additive and the additive amount; a reaction area acquisition step for acquiring a reaction area of ​​the electrode plate relative to the specific surface area of ​​the electrode plate when the type of additive and the additive amount are changed; and a target specific surface area acquisition step for acquiring a target specific surface area of ​​the electrode plate relative to the reaction area of ​​the electrode plate. [Effects of the Invention]

[0014] According to the present invention, the characteristics of a nonaqueous secondary battery can be improved. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view of a lithium ion secondary battery according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a laminate of electrode bodies of a lithium ion secondary battery. [Figure 3] 1 is a flowchart showing a manufacturing process of an electrode plate for a lithium ion secondary battery. [Figure 4] FIG. 2 is a schematic diagram showing the relationship between the amount of a negative electrode additive and the specific surface area of ​​a negative electrode plate. [Figure 5] FIG. 2 is a schematic diagram showing the relationship between the amount of a negative electrode additive and the specific surface area of ​​a negative electrode plate. [Figure 6] 1 is a schematic diagram showing the relationship between the specific surface area of ​​a negative electrode plate and the reaction area of ​​the negative electrode plate, and the relationship between the specific surface area of ​​a negative electrode plate and the reaction area of ​​the negative electrode plate due to pressing in a pressing process. FIG. [Figure 7] 1 is a schematic diagram showing the relationship between the specific surface area of ​​a negative electrode plate and the reaction area of ​​the negative electrode plate, and the relationship between the specific surface area of ​​a negative electrode plate and the reaction area of ​​the negative electrode plate due to pressing in a pressing process. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] [First embodiment] Hereinafter, an embodiment of a method for manufacturing an electrode plate for a nonaqueous secondary battery and a method for manufacturing a nonaqueous secondary battery will be described.

[0017] <Lithium-ion secondary battery 10> As an example of a nonaqueous secondary battery, the structure of a lithium ion secondary battery will be described. As shown in FIG. 1, the lithium ion secondary battery 10 is configured as a cell battery. The lithium ion secondary battery 10 includes a battery case 11. The battery case 11 includes a lid 12. The battery case 11 includes an opening (not shown) on the upper side. The lid 12 seals the opening. The battery case 11 is made of a metal such as an aluminum alloy. The lid 12 includes a negative electrode external terminal 13 and a positive electrode external terminal 14 used for charging and discharging power. The negative electrode external terminal 13 and the positive electrode external terminal 14 may have any shape.

[0018] The lithium ion secondary battery 10 includes an electrode assembly 15. The lithium ion secondary battery 10 includes a negative electrode current collector 16 and a positive electrode current collector 17. The negative electrode current collector 16 connects the negative electrode of the electrode assembly 15 to a negative electrode external terminal 13. The positive electrode current collector 17 connects the positive electrode of the electrode assembly 15 to a positive electrode external terminal 14. The electrode assembly 15 is housed inside a battery case 11.

[0019] The lithium ion secondary battery 10 includes a non-aqueous electrolyte 18. The non-aqueous electrolyte 18 is injected into the battery case 11 through a filling hole (not shown). The lithium ion secondary battery 10 is configured as a sealed battery container by attaching a lid 12 to the opening of the battery case 11. In this manner, the battery case 11 accommodates the electrode assembly 15 and the non-aqueous electrolyte 18.

[0020] <Nonaqueous electrolyte 18> The nonaqueous electrolyte 18 is a composition in which a supporting salt is contained in a nonaqueous solvent. In this embodiment, ethylene carbonate (EC) can be used as the nonaqueous solvent. The nonaqueous solvent may be one or more materials selected from the group consisting of propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), etc.

[0021] The supporting electrolyte may be LiPF, LiBF, LiClO, LiAsF, LiCF, SO, LiC, F, SO, LiN(CF, SO), LiC(CF, SO), LiI, or the like. Alternatively, one or more lithium compounds (lithium salts) selected from these may be used. Thus, the nonaqueous electrolyte 18 contains a lithium compound.

[0022] <Electrode body 15> As shown in FIG. 2, the electrode assembly 15 includes a negative electrode plate 20, a positive electrode plate 30, and a separator 40. The longitudinal direction of the electrode assembly 15 is referred to as the "lengthwise direction Z." The thickness direction of the electrode assembly 15 is referred to as the "thickness direction D." The direction intersecting the lengthwise direction Z and the thickness direction D of the electrode assembly 15 is referred to as the "widthwise direction W." One direction of the widthwise directions W is referred to as the "first widthwise direction W1," and the other direction of the widthwise directions W is referred to as the "second widthwise direction W2." In other words, the second widthwise direction W2 is the opposite direction to the first widthwise direction W1.

[0023] The electrode body 15 is formed by stacking a negative electrode plate 20, a positive electrode plate 30, and a separator 40 in the thickness direction D. The separator 40 is provided between the negative electrode plate 20 and the positive electrode plate 30. Specifically, the electrode body 15 is formed by stacking the separator 40, the positive electrode plate 30, the separator 40, and the negative electrode plate 20 in this order.

[0024] The electrode assembly 15 is formed by stacking a negative electrode plate 20, a positive electrode plate 30, and a separator 40 in a thickness direction D and then winding them in a length direction Z. The electrode assembly 15 has a flat shape in the thickness direction D at the center in the length direction Z.

[0025] In this way, the thickness direction D in which the negative electrode plate 20, the positive electrode plate 30, and the separator 40 are stacked can also be referred to as the stacking direction. In addition, the length direction Z in which the negative electrode plate 20, the positive electrode plate 30, and the separator 40 are wound can also be referred to as the winding direction. The electrode body 15 has a flat shape in the thickness direction D.

[0026] <Negative electrode plate 20> The negative electrode plate 20 functions as an example of a negative electrode of the lithium-ion secondary battery 10. The negative electrode plate 20 includes a negative electrode substrate 21 and a negative electrode composite layer 22. The negative electrode substrate 21 is an electrode substrate of the negative electrode. The negative electrode composite layer 22 is an electrode composite layer of the negative electrode, and is provided on both sides of the negative electrode substrate 21.

[0027] The negative electrode substrate 21 has a negative electrode connecting portion 23. The negative electrode connecting portion 23 is a region where the negative electrode composite layer 22 is not provided on either side of the negative electrode substrate 21. The negative electrode connecting portion 23 is provided at an end portion in the first width direction W1 of the electrode body 15. The negative electrode connecting portion 23 is exposed from the positive electrode plate 30 and the separator 40 in the first width direction W1.

[0028] In this embodiment, negative electrode substrate 21 is made of Cu foil. Negative electrode substrate 21 serves as a base for the aggregate of negative electrode composite layer 22. Negative electrode substrate 21 functions as a current collecting member that collects electricity from negative electrode composite layer 22.

[0029] Negative electrode mixture layer 22 has a negative electrode active material and a negative electrode additive. Negative electrode plate 20 is produced, for example, by kneading the negative electrode active material and the negative electrode additive, applying the kneaded negative electrode mixture paste to negative electrode substrate 21, and drying the paste.

[0030] In this embodiment, the negative electrode active material is an active material of the negative electrode, and is a material capable of absorbing and releasing lithium ions. As the negative electrode active material, for example, a powdered carbon material made of graphite or the like can be used.

[0031] The negative electrode additive is an additive for the negative electrode and includes a negative electrode solvent, a negative electrode binder, and a negative electrode thickener. The negative electrode solvent may be, for example, water. The negative electrode solvent may evaporate during the manufacture of the lithium-ion secondary battery 10 and may not remain in the negative electrode mixture layer 22 after manufacture. The negative electrode binder may be, for example, styrene butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), or the like. The negative electrode thickener may be, for example, carboxymethyl cellulose (CMC), or the like. The negative electrode additive may further include, for example, a negative electrode conductive material.

[0032] <Positive electrode plate 30> The positive electrode plate 30 functions as an example of a positive electrode of the lithium-ion secondary battery 10. The positive electrode plate 30 includes a positive electrode substrate 31 and a positive electrode composite layer 32. The positive electrode substrate 31 is an electrode substrate of the positive electrode. The positive electrode composite layer 32 is an electrode composite layer of the positive electrode, and is provided on both sides of the positive electrode substrate 31.

[0033] The positive electrode substrate 31 includes a positive electrode connection portion 33. The positive electrode connection portion 33 is a region where the positive electrode composite layer 32 is not provided on either side of the positive electrode substrate 31. The positive electrode connection portion 33 is provided at an end portion of the electrode body 15 in the second width direction W2. The positive electrode connection portion 33 is exposed from the negative electrode plate 20 and the separator 40 in the second width direction W2.

[0034] In this embodiment, positive electrode substrate 31 is made of Al foil or Al alloy foil. Positive electrode substrate 31 serves as a base for the aggregate of positive electrode mixture layer 32. Positive electrode substrate 31 functions as a current collecting member that collects electricity from positive electrode mixture layer 32.

[0035] Positive electrode mixture layer 32 has a positive electrode active material and a positive electrode additive. Positive electrode plate 30 is produced, for example, by kneading the positive electrode active material and the positive electrode additive, applying the kneaded positive electrode mixture paste to positive electrode substrate 31, and drying the paste.

[0036] The positive electrode active material is an active material of the positive electrode, and is a material capable of absorbing and releasing lithium. Examples of the positive electrode active material that can be used include lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), and lithium nickel oxide (LiNiO2). Also, a material in which LiCoO2, LiMn2O4, and LiNiO2 are mixed in any ratio may be used.

[0037] The positive electrode additive is an additive for the positive electrode and includes a positive electrode solvent, a positive electrode conductive material, and a positive electrode binder. For example, an NMP (N-methyl-2-pyrrolidone) solution can be used as the positive electrode solvent. The positive electrode solvent may evaporate during the manufacture of the lithium-ion secondary battery 10 and may not remain in the positive electrode mixture layer 32 after manufacture. For example, carbon black such as acetylene black (AB) or ketjen black, graphite, etc. can be used as the positive electrode conductive material. For example, the same material as the negative electrode binder can be used as the positive electrode binder. The positive electrode additive may further include, for example, a positive electrode thickener, etc.

[0038] <Separator 40> The separator 40 is disposed between the negative electrode plate 20 and the positive electrode plate 30. The separator 40 holds the non-aqueous electrolyte 18. The separator 40 is a nonwoven fabric made of a porous resin such as polypropylene. The separator 40 may be a porous polymer membrane such as a porous polyethylene membrane, a porous polyolefin membrane, or a porous polyvinyl chloride membrane, or a lithium ion or ion conductive polymer electrolyte membrane, either singly or in combination. When the electrode assembly 15 is immersed in the non-aqueous electrolyte 18, the non-aqueous electrolyte 18 permeates the separator 40 from the edges toward the center.

[0039] <Manufacturing Process of Lithium-ion Secondary Battery 10> Here, the manufacturing process of the lithium ion secondary battery 10 of this embodiment will be described. In this embodiment, a source process is performed. As will be described in detail later, the source process is a process for producing the battery elements of the lithium-ion secondary battery 10. Specifically, the source process is a process for producing the negative electrode plate 20 and the positive electrode plate 30 that constitute the battery elements of the lithium-ion secondary battery 10.

[0040] After the source process is completed, the assembly process is carried out. In the assembly process, the lithium-ion secondary battery 10 is assembled. In the assembly process, the electrode body 15 is first manufactured. Specifically, the positive electrode plate 30 and the negative electrode plate 20 are first stacked with the separator 40 interposed therebetween, then wound and pressed flat. Thereafter, the negative electrode connection portion 23 is pressure-welded, and the positive electrode connection portion 33 is pressure-welded. Through the above procedure, the electrode body 15 is manufactured.

[0041] Next, the electrode assembly 15 is housed in the battery case 11. At this time, the positive electrode connection portion 33 is electrically connected to the positive electrode external terminal 14 via the positive electrode current collector 17. The negative electrode connection portion 23 is electrically connected to the negative electrode external terminal 13 via the negative electrode current collector 16. The opening of the battery case 11 is closed with the lid 12. Then, the nonaqueous electrolyte 18 is poured into the battery case 11. After the pouring of the nonaqueous electrolyte 18 into the battery case 11 is completed, the battery case 11 is sealed. Through the above procedure, the lithium-ion secondary battery 10 is assembled.

[0042] <Source process> Here, the source process of this embodiment will be described with reference to Fig. 3. Hereinafter, the process of producing the negative electrode plate 20 will be described, and the process of producing the positive electrode plate 30 will not be described because it is the same process.

[0043] As shown in Fig. 3, a target specific surface area calculation step is performed in step S10. The target specific surface area calculation step is a step of calculating a target specific surface area of ​​the negative electrode plate 20 based on the composition of the negative electrode additive. The target specific surface area of ​​the negative electrode plate 20 is a specific surface area that is targeted for the negative electrode plate 20 after manufacture so that the reaction area of ​​the negative electrode plate 20 after manufacture is a suitable area in terms of design. In more detail, the target specific surface area calculation step includes an additive amount acquisition step, a specific surface area acquisition step, a reaction area acquisition step, and a target specific surface area acquisition step.

[0044] The composition of the negative electrode additive includes the type of negative electrode additive added to the negative electrode active material and the amount of the negative electrode additive added to the negative electrode active material. The types of negative electrode additive include, for example, a negative electrode binder and a negative electrode thickener. In this embodiment, the negative electrode binder corresponds to an example of an additive and a first additive, and the negative electrode thickener corresponds to an example of an additive and a second additive.

[0045] In the target specific surface area calculation process, first, in step S11, an addition amount acquisition process is performed. The addition amount acquisition process is a process of acquiring the addition amount of the negative electrode additive by measuring the addition amount of the negative electrode additive to be added to the negative electrode active material. In this way, the addition amount acquisition process is a process of acquiring the composition of the negative electrode additive to be added to the negative electrode active material.

[0046] The addition amount obtaining step also includes a step of obtaining the amount of each type of anode additive added to the anode active material. Specifically, the addition amount obtaining step includes a step of measuring the amount of anode binder added to the anode active material to obtain the amount of anode binder as the amount of anode additive added. The addition amount obtaining step includes a step of measuring the amount of anode thickener added to the anode active material to obtain the amount of anode thickener as the amount of anode additive added.

[0047] After the addition amount obtaining step is completed, a specific surface area obtaining step is performed in step S12. As will be described in detail later, the specific surface area obtaining step is a step of obtaining the specific surface area of ​​the negative electrode plate 20 in accordance with the composition of the negative electrode additive added to the negative electrode active material. In other words, the specific surface area obtaining step is a step of obtaining the specific surface area of ​​the negative electrode plate 20 in accordance with the type of negative electrode additive added to the negative electrode active material and the amount of negative electrode additive added. The specific surface area of ​​the negative electrode plate 20 obtained in the specific surface area obtaining step is a specific surface area predicted in accordance with the composition of the negative electrode additive added to the negative electrode active material.

[0048] After the specific surface area acquisition step is completed, a reaction area acquisition step is performed in step S13. As will be described in detail later, the reaction area acquisition step is a step of acquiring the reaction area of ​​the negative electrode plate 20 according to the type of negative electrode active material and the specific surface area of ​​the negative electrode plate 20 acquired in the specific surface area acquisition step. In other words, the reaction area acquisition step is a step of acquiring the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20 when the amount of negative electrode additive added is changed. The reaction area of ​​the negative electrode plate 20 acquired in the reaction area acquisition step is a reaction area predicted according to the composition of the negative electrode additive added to the negative electrode active material.

[0049] After the reaction area acquisition process is completed, a target specific surface area acquisition process is performed in step S14. As will be described in detail later, the target specific surface area acquisition process is a process for acquiring a target specific surface area of ​​the negative electrode plate 20 so that the reaction area of ​​the negative electrode plate 20 becomes the reference reaction area. In other words, the target specific surface area acquisition process acquires a target specific surface area of ​​the negative electrode plate 20 relative to the reaction area of ​​the negative electrode plate 20. The target specific surface area of ​​the negative electrode plate 20 is the specific surface area targeted for the manufactured negative electrode plate 20, and is the specific surface area predicted depending on the composition of the negative electrode additive added to the negative electrode active material. The reference reaction area of ​​the negative electrode plate 20 corresponds to the design median of the reaction area and corresponds to the design-preferred reaction area for the manufactured negative electrode plate 20. In this way, the target specific surface area of ​​the negative electrode plate 20 is the specific surface area for making the reaction area of ​​the manufactured negative electrode plate 20 the design-preferred reaction area.

[0050] After the target specific surface area calculation step is completed, a blending step is performed in step S15. The blending step includes blending a negative electrode active material and a negative electrode additive, which are raw materials for negative electrode composite layer 22. This produces a negative electrode composite paste. Then, a kneading step is performed in step S16. The kneading step includes kneading the negative electrode composite paste.

[0051] After the kneading step is completed, a coating step is performed in step S17. In the coating step, the negative electrode composite paste is applied to both surfaces of the negative electrode substrate 21 so as to form negative electrode connecting portions 23 at both ends in the width direction W. Then, in step S18, a drying step is performed. In the drying step, the negative electrode composite paste applied to the negative electrode substrate 21 is dried to form negative electrode composite layer 22.

[0052] After the drying step is completed, a pressing step is performed in step S19. In the pressing step, negative electrode composite layer 22 formed on both surfaces of negative electrode substrate 21 is pressed to increase the adhesive strength of negative electrode composite layer 22 to negative electrode substrate 21 and adjust the thickness of negative electrode composite layer 22. In other words, the pressing step is a step of pressing negative electrode composite layer 22 on negative electrode substrate 21. As will be described in detail later, the pressing step is a step of pressing negative electrode composite layer 22 based on the target specific surface area of ​​negative electrode plate 20 acquired in the target specific surface area acquisition step.

[0053] After the pressing step is completed, a cutting step is carried out in step S20. In the cutting step, the negative electrode plate 20 is cut at the center in the width direction W. Through the above steps, two negative electrode plates 20 are produced at once.

[0054] <Specific surface area acquisition process> Here, a specific example of the specific surface area acquisition step will be described in detail. In the specific surface area acquisition step, the specific surface area of ​​the negative electrode plate 20 relative to the composition of the negative electrode additive added to the negative electrode active material is acquired based on the correlation line shown in Fig. 4.

[0055] 4, in the graph 50, the vertical axis represents the specific surface area of ​​the negative electrode plate 20, and the horizontal axis represents the amount of the negative electrode additive added. The specific surface area of ​​the negative electrode plate 20 is calculated in advance from the measurement results according to the composition of the negative electrode additive.

[0056] Graph 50 shows a first correlation line 51. First correlation line 51 is a line showing the correlation between the amount of negative electrode binder added to the negative electrode active material and the specific surface area of ​​negative electrode plate 20. First correlation line 51 is a line showing that the amount of negative electrode binder added to the negative electrode active material is inversely proportional to the specific surface area of ​​negative electrode plate 20. First correlation line 51 is a line showing that when the amount of negative electrode binder added to the negative electrode active material is a reference amount A10, the specific surface area of ​​negative electrode plate 20 becomes a reference specific surface area B0. Reference specific surface area B0 corresponds to the design median value of the specific surface area of ​​negative electrode plate 20. Reference amount A10 corresponds to the design median value of the amount of negative electrode binder added.

[0057] The graph 50 shows a second correlation line 52. The second correlation line 52 is a line that shows the correlation between the amount of negative electrode thickener added to the negative electrode active material and the specific surface area of ​​the negative electrode plate 20. The second correlation line 52 is a line that shows the inverse proportionality between the amount of negative electrode thickener added to the negative electrode active material and the specific surface area of ​​the negative electrode plate 20. The second correlation line 52 is a line that shows the specific surface area of ​​the negative electrode plate 20 as a reference specific surface area B0 when the amount of negative electrode thickener added to the negative electrode active material is a reference amount A20. The reference amount A20 corresponds to the design median value of the amount of negative electrode thickener added.

[0058] As described above, the relationship between the amount of the negative electrode additive and the specific surface area of ​​the negative electrode plate 20 varies depending on the type of negative electrode additive. In other words, the specific surface area of ​​the negative electrode plate 20 varies depending on the type and amount of the negative electrode additive, and it can also be said that the specific surface area of ​​the negative electrode plate 20 varies depending on the composition of the negative electrode additive. Specifically, the smaller the amount of negative electrode binder added to the negative electrode active material, the larger the specific surface area of ​​the negative electrode plate 20. Furthermore, the smaller the amount of negative electrode thickener added to the negative electrode active material, the larger the specific surface area of ​​the negative electrode plate 20.

[0059] 5, when the amount of added negative electrode binder acquired in the addition amount acquisition step is the amount indicated by reference symbol A11, the specific surface area of ​​the negative electrode plate 20 for the amount of added negative electrode binder is acquired based on the first correlation line 51 in the specific surface area acquisition step. In this case, the amount indicated by reference symbol A11 is less than the reference amount A10. The specific surface area of ​​the negative electrode plate 20 increases by a difference ΔB1 from the reference specific surface area B0, as indicated by reference symbol 53 of the first correlation line 51.

[0060] Furthermore, if the amount of negative electrode thickener added acquired in the addition amount acquisition step is the amount indicated by reference symbol A21, the specific surface area of ​​the negative electrode plate 20 for the amount of negative electrode thickener added is acquired in the specific surface area acquisition step based on the second correlation line 52. In this case, the amount indicated by reference symbol A21 is less than the reference amount A20. The specific surface area of ​​the negative electrode plate 20 increases by a difference ΔB2 from the reference specific surface area B0, as indicated by reference symbol 54 of the second correlation line 52.

[0061] <Reaction area acquisition process> Next, a specific example of the reaction area acquisition step will be described in detail. In the reaction area acquisition step, the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20 acquired in the specific surface area acquisition step is acquired based on the correlation line as shown in Fig. 6.

[0062] As shown in FIG. 6, in a graph 60, the vertical axis represents the electric double layer capacity of the negative electrode plate 20, and the horizontal axis represents the specific surface area of ​​the negative electrode plate 20. In the figure, the electric double layer capacity of the negative electrode plate 20 is simply referred to as capacity. The electric double layer capacity of the negative electrode plate 20 is calculated by an electrochemical method. In addition, the electric double layer capacity of the negative electrode plate 20 is approximated to the reaction area of ​​the negative electrode plate 20, and will be hereinafter described as the reaction area of ​​the negative electrode plate 20.

[0063] The graph 60 shows a third correlation line 61. The third correlation line 61 is a line that shows the correlation between the specific surface area of ​​the negative electrode plate 20 obtained from the amount of negative electrode binder added and the reaction area of ​​the negative electrode plate 20. The third correlation line 61 is a line that shows that the specific surface area of ​​the negative electrode plate 20 is proportional to the reaction area of ​​the negative electrode plate 20. The third correlation line 61 is a line that passes through the point where the specific surface area of ​​the negative electrode plate 20 is the reference specific surface area B0 and the reaction area of ​​the negative electrode plate 20 is the reference reaction area C0.

[0064] The graph 60 shows a fourth correlation line 62. The fourth correlation line 62 is a line that shows the correlation between the specific surface area of ​​the negative electrode plate 20 obtained from the amount of negative electrode thickener added and the reaction area of ​​the negative electrode plate 20. The fourth correlation line 62 is a line that shows that the specific surface area of ​​the negative electrode plate 20 is proportional to the reaction area of ​​the negative electrode plate 20. The fourth correlation line 62 is a line that passes through the point where the specific surface area of ​​the negative electrode plate 20 is the reference specific surface area B0 and the reaction area of ​​the negative electrode plate 20 is the reference reaction area C0.

[0065] In this way, the reaction area of ​​the negative electrode plate 20 differs from the specific surface area of ​​the negative electrode plate 20 obtained from the type and amount of the negative electrode additive. As a result, the smaller the amount of the negative electrode binder added, the larger the specific surface area of ​​the negative electrode plate 20, and the larger the reaction area of ​​the negative electrode plate 20. Also, the smaller the amount of the negative electrode thickener added, the larger the specific surface area of ​​the negative electrode plate 20, and the larger the reaction area of ​​the negative electrode plate 20.

[0066] In particular, when the third correlation line 61 and the fourth correlation line 62 are compared, the third correlation line 61 and the fourth correlation line 62 differ in the amount of change in the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20. More specifically, when the third correlation line 61 and the fourth correlation line 62 are compared, the third correlation line 61 has a larger amount of change in the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20 than the fourth correlation line 62. For this reason, the relationship between the specific surface area of ​​the negative electrode plate 20 obtained from the amount of negative electrode additive added and the reaction area of ​​the negative electrode plate 20 differs depending on the type of negative electrode additive added to the negative electrode active material.

[0067] 7, when the specific surface area of ​​the negative electrode plate 20 obtained from the amount of added negative electrode binder increases by a difference ΔB1 from the reference specific surface area B0, the reaction area of ​​the negative electrode plate 20 increases by a difference ΔC1 with respect to the reference reaction area C0 based on the third correlation line 61. In this way, in the reaction area obtaining step, the reaction area of ​​the negative electrode plate 20 with respect to the specific surface area of ​​the negative electrode plate 20 based on the amount of added negative electrode binder is obtained.

[0068] Furthermore, when the specific surface area of ​​the negative electrode plate 20 obtained from the amount of negative electrode thickener added increases by a difference ΔB2 from the reference specific surface area B0, the reaction area of ​​the negative electrode plate 20 increases by a difference ΔC2 based on the fourth correlation line 62A, as indicated by the reference numeral 65. The fourth correlation line 62A has the same slope as the fourth correlation line 62 and is a line that passes through the point indicated by the reference numeral 64. The point indicated by the reference numeral 64 is the point where the specific surface area of ​​the negative electrode plate 20 is the sum of the reference specific surface area B0 and the difference ΔB1, and where the reaction area of ​​the negative electrode plate 20 is the sum of the reference reaction area C0 and the difference ΔC1. In this way, in the reaction area obtaining step, the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20 based on the amount of negative electrode thickener added is obtained.

[0069] As a result, the reaction area of ​​the negative electrode plate 20 obtained from the amount of negative electrode binder added and the amount of negative electrode thickener added increases by the sum of the difference ΔC1 and the difference ΔC2, based on the third correlation line 61 and the fourth correlation line 62, with the reference reaction area C0 as the reference.

[0070] <Target specific surface area acquisition process> Next, a specific example of the target specific surface area acquisition step will be described in detail. In the target specific surface area acquisition step, a target specific surface area of ​​the negative electrode plate 20 relative to the reaction area of ​​the negative electrode plate 20 acquired in the reaction area acquisition step is acquired based on the correlation line shown in Fig. 6.

[0071] As shown in FIG. 6 , graph 60 shows a fifth correlation line 63. Fifth correlation line 63 is a line that shows the correlation between the specific surface area of ​​negative electrode plate 20 and the reaction area of ​​negative electrode plate 20 when negative electrode composite layer 22 is pressed in the pressing process. In other words, fifth correlation line 63 shows the reaction area of ​​negative electrode plate 20 relative to the specific surface area of ​​negative electrode plate 20 adjusted in the pressing process. Fifth correlation line 63 is a line that shows the proportionality between the specific surface area of ​​negative electrode plate 20 and the reaction area of ​​negative electrode plate 20. Furthermore, fifth correlation line 63 is a line that passes through the point where the specific surface area of ​​negative electrode plate 20 is the reference specific surface area B0 and the reaction area of ​​negative electrode plate 20 is the reference reaction area C0.

[0072] As shown in FIG. 7 , the target specific surface area of ​​the negative electrode plate 20 is the specific surface area when the reaction area of ​​the negative electrode plate 20 is the reference reaction area C0. Based on the fifth correlation line 63A, the target specific surface area is the specific surface area indicated by the reference symbol B3, as indicated by the reference symbol 66. The fifth correlation line 63A has the same slope as the fifth correlation line 63 and is a line passing through the point indicated by the reference symbol 65. The point indicated by the reference symbol 65 is the point where the specific surface area of ​​the negative electrode plate 20 is the sum of the reference specific surface area B0, the differences ΔB1 and ΔB2, and the reaction area of ​​the negative electrode plate 20 is the sum of the reference reaction area C0, the differences ΔC1 and ΔC2. The target specific surface area of ​​the negative electrode plate 20 corresponds to the specific surface area targeted in the pressing process and is the specific surface area where the reaction area of ​​the manufactured negative electrode plate 20 is the preferred reaction area in terms of design.

[0073] In this way, in the target specific surface area acquisition process, the target specific surface area of ​​the negative electrode plate 20 is acquired relative to the reaction area of ​​the negative electrode plate 20 based on the amount of negative electrode binder added and the reaction area of ​​the negative electrode plate 20 based on the amount of negative electrode thickener added.

[0074] Then, in the pressing step, the negative electrode composite layer 22 is pressed so as to have the target specific surface area of ​​the negative electrode plate 20 acquired in the target specific surface area acquisition process. That is, in the pressing step, the negative electrode composite layer 22 is pressed based on the target specific surface area of ​​the negative electrode plate 20 acquired in the target specific surface area acquisition step. As a result, even if the type and amount of the negative electrode additive change and the relationship between the specific surface area of ​​the negative electrode plate 20 and the reaction area of ​​the negative electrode plate 20 changes, the reaction area of ​​the negative electrode plate 20 can be adjusted to a suitable reference reaction area C0 in terms of design.

[0075] <Actions and Effects of the First Embodiment> The operation and effects of the first embodiment will be described. (1) In a specific surface area acquisition step, the specific surface area of ​​the negative electrode plate 20 relative to the type and amount of negative electrode additive is acquired. In a reaction area acquisition step, the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20 is acquired for each type of negative electrode additive. Then, in a target specific surface area acquisition step, the target specific surface area of ​​the negative electrode plate 20 relative to the reaction area of ​​the negative electrode plate 20 is acquired.

[0076] Conventionally, the reaction area of ​​the negative electrode plate 20 relative to the specific surface area of ​​the negative electrode plate 20 was calculated independently of the composition of the negative electrode additive added to the negative electrode active material, but this resulted in variations in the accuracy of the reaction area of ​​the negative electrode plate 20.

[0077] This was found to be because the relationship between the specific surface area of ​​the negative electrode plate 20 and the reaction area of ​​the negative electrode plate 20 changes depending on the composition of the negative electrode additive added to the negative electrode active material, as shown in graph 60 of Fig. 6. To give a specific example, in the past, as shown in graph 60 of Fig. 7, if the specific surface area of ​​the negative electrode plate 20 was adjusted to a reference specific surface area B0 without depending on the composition of the negative electrode additive added to the negative electrode active material, the reaction area of ​​the negative electrode plate 20 would be smaller than the reference reaction area C0.

[0078] In addition, it was also found that when adjusting the amount of negative electrode additive to be added to the negative electrode active material in the manufacturing process of the negative electrode plate 20, it is not easy to improve the accuracy of adjusting the amount of negative electrode additive, which causes variations in the amount of negative electrode additive to be added.

[0079] Therefore, in this embodiment, by adopting the above configuration, it is possible to obtain a target specific surface area of ​​the negative electrode plate 20 according to the type and amount of the negative electrode additive. As a result, even if at least one of the type and amount of the negative electrode additive changes, it is possible to adjust the reaction area of ​​the negative electrode plate 20 to a suitable reaction area in terms of design. Therefore, by improving the manufacturing precision of the negative electrode plate 20, it is possible to suppress a decrease in capacity of the lithium-ion secondary battery 10 and improve the characteristics of the lithium-ion secondary battery 10.

[0080] (2) Even when a negative electrode binder and a negative electrode thickener are added to the negative electrode active material as negative electrode additives, it is possible to obtain a target specific surface area of ​​the negative electrode plate 20 relative to the reaction area of ​​the negative electrode plate 20 based on the amount of negative electrode binder added and the reaction area of ​​the negative electrode plate 20 based on the amount of negative electrode thickener added. This makes it possible to adjust the reaction area of ​​the negative electrode plate 20 to a suitable reaction area in terms of design, even when the combination of negative electrode additives added to the negative electrode active material changes. Therefore, by improving the manufacturing precision of the negative electrode plate 20 based on the specific surface area of ​​the negative electrode plate 20, it is possible to suppress a decrease in capacity of the lithium-ion secondary battery 10 and improve the characteristics of the lithium-ion secondary battery 10.

[0081] (3) In the target specific surface area acquisition step, a target specific surface area of ​​the negative electrode plate 20 in the pressing step is acquired based on the reaction area of ​​the negative electrode plate 20. Then, in the pressing step, the negative electrode composite layer 22 in the negative electrode substrate 21 is pressed based on the target specific surface area of ​​the negative electrode plate 20. Therefore, in the pressing step, the reaction area of ​​the negative electrode plate 20 can be adjusted by adjusting the specific surface area of ​​the negative electrode plate 20 to be the target specific surface area of ​​the negative electrode plate 20. Furthermore, the reaction area of ​​the negative electrode plate 20 after completion of the pressing step is the reaction area of ​​the negative electrode plate 20 after the negative electrode plate 20 is manufactured, and the reaction area of ​​the negative electrode plate 20 after the negative electrode plate 20 is manufactured can be adjusted in the pressing step.

[0082] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0083] In the present embodiment, for example, the reaction area of ​​the negative electrode plate 20 may be acquired based on the specific surface area of ​​the negative electrode plate 20 itself, rather than the difference in the specific surface area of ​​the negative electrode plate 20. For example, the target specific surface area of ​​the negative electrode plate 20 may be acquired based on the reaction area of ​​the negative electrode plate 20 itself, rather than the difference in the reaction area of ​​the negative electrode plate 20.

[0084] In the present embodiment, the target specific surface area of ​​the negative electrode plate 20 after the manufacture of the negative electrode plate 20 is acquired. However, this is not limiting, and the target specific surface area of ​​the negative electrode plate 20 may be acquired during the manufacturing process of the negative electrode plate 20, such as during a kneading process or a drying process. That is, the target specific surface area of ​​the negative electrode plate 20 during the manufacture of the negative electrode plate 20 may be acquired. Furthermore, for example, the negative electrode plate 20 may be manufactured based on the target specific surface area of ​​the negative electrode plate 20 during the manufacturing process of the negative electrode plate 20.

[0085] In the present embodiment, for example, the additives may include at least one of a binder and a thickener, or may include additives other than a binder and a thickener. Furthermore, for example, the additive amount to be acquired may be one type or two or more types.

[0086] In this embodiment, for example, the manufacturing method of the negative electrode plate 20 may be applied to the manufacturing method of the positive electrode plate 30, or a combination thereof may be used. In other words, the present invention may be applied to the manufacturing method of an electrode plate for a non-aqueous secondary battery and the manufacturing method of a non-aqueous secondary battery, regardless of whether it is the negative electrode plate 20 or the positive electrode plate 30.

[0087] In the present embodiment, the present invention has been described using the lithium ion secondary battery 10 as an example, but it can also be applied to other secondary batteries. In the present embodiment, a thin-plate lithium-ion secondary battery 10 for vehicle use is illustrated, but the present invention can also be applied to cylindrical batteries. Furthermore, the present invention is not limited to vehicle use, but can also be applied to batteries for ships, aircraft, and even stationary use.

[0088] The phrase "at least any" used herein means one or more of the desired options. As an example, when the number of options is two, the phrase "at least any" used herein means only one option or both options. As another example, when the number of options is three or more, the phrase "at least any" used herein means only one option or any combination of two or more options.

[0089] It goes without saying that those skilled in the art can add, delete, or modify the components of the present invention, and change the order of the components, without departing from the scope of the claims. [Explanation of symbols]

[0090] D: Thickness direction W: Width direction Z: Length direction 10...Lithium-ion secondary battery 11...Battery case 12...lid body 13...Negative external terminal 14...Positive external terminal 15...Electrode body 16...Negative electrode current collector 17...Positive electrode current collector 18...Nonaqueous electrolyte 20...Negative electrode plate 21...Anode substrate 22...Negative electrode composite material layer 23...Negative electrode connection part 30...Positive electrode plate 31...Positive electrode substrate 32...Positive electrode mixture layer 33...Positive electrode connection part 40...Separator

Claims

1. A method for manufacturing an electrode plate for a non-aqueous secondary battery, comprising: an electrode base material; and an electrode mixture layer containing at least an active material and an additive, an addition amount acquisition step of acquiring the addition amount of the additive; a specific surface area acquisition step of acquiring a specific surface area of ​​the electrode plate for a non-aqueous secondary battery for the type and amount of the additive; a reaction area acquisition step of acquiring a reaction area of ​​the electrode plate for a non-aqueous secondary battery relative to a specific surface area of ​​the electrode plate for a non-aqueous secondary battery when the type of the additive and the amount of the additive added are changed; a target specific surface area acquisition step of acquiring a target specific surface area of ​​the non-aqueous secondary battery electrode plate relative to a reaction area of ​​the non-aqueous secondary battery electrode plate, A method for manufacturing an electrode plate for a non-aqueous secondary battery.

2. The method for producing an electrode plate for a non-aqueous secondary battery according to claim 1, the addition amount acquisition step acquires an addition amount of a first additive and an addition amount of a second additive as the addition amounts of the additives; the specific surface area obtaining step includes obtaining a specific surface area of ​​the non-aqueous secondary battery electrode plate relative to the amount of the first additive and a specific surface area of ​​the non-aqueous secondary battery electrode plate relative to the amount of the second additive; the reaction area obtaining step obtains a reaction area of ​​the non-aqueous secondary battery electrode plate relative to a specific surface area of ​​the non-aqueous secondary battery electrode plate based on an added amount of the first additive, and a reaction area of ​​the non-aqueous secondary battery electrode plate relative to a specific surface area of ​​the non-aqueous secondary battery electrode plate based on an added amount of the second additive, the target specific surface area acquisition step acquires a target specific surface area of ​​the non-aqueous secondary battery electrode plate relative to a reaction area of ​​the non-aqueous secondary battery electrode plate based on the addition amount of the first additive and a reaction area of ​​the non-aqueous secondary battery electrode plate based on the addition amount of the second additive; A method for manufacturing an electrode plate for a non-aqueous secondary battery.

3. 3. The method for producing an electrode plate for a non-aqueous secondary battery according to claim 1 or 2, The additive includes at least one of a binder and a thickener. A method for manufacturing an electrode plate for a non-aqueous secondary battery.

4. 3. The method for producing an electrode plate for a non-aqueous secondary battery according to claim 1 or 2, a pressing step of pressing the electrode mixture layer on the electrode base material, the target specific surface area obtaining step obtains a target specific surface area of ​​the non-aqueous secondary battery electrode plate in the pressing step according to a reaction area of ​​the non-aqueous secondary battery electrode plate; the pressing step presses the electrode mixture layer on the electrode base material based on a target specific surface area of ​​the electrode plate for a non-aqueous secondary battery; A method for manufacturing an electrode plate for a non-aqueous secondary battery.

5. A method for manufacturing a nonaqueous secondary battery including an electrode plate having an electrode base material and an electrode mixture layer containing at least an active material and an additive, comprising: an addition amount acquisition step of acquiring the addition amount of the additive; a specific surface area acquisition step of acquiring a specific surface area of ​​the electrode plate with respect to the type and amount of the additive; a reaction area acquisition step of acquiring a reaction area of ​​the electrode plate relative to the specific surface area of ​​the electrode plate when the type of the additive and the amount of the additive added are changed; A target specific surface area acquisition step of acquiring a target specific surface area of ​​the electrode plate with respect to the reaction area of ​​the electrode plate, A method for manufacturing a non-aqueous secondary battery.

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