Secondary battery laminate, secondary battery, and method for producing the same

Abstract

The present invention provides a laminate for secondary batteries that can suppress curling of separators. The manufacturing method of the laminate for secondary batteries of the present invention includes process (A) and process (B), wherein the process (A) is a process for preparing the following laminate, which is a laminate having a negative electrode material and a separator raw material bonded to both sides of the negative electrode material, or a laminate formed by bonding the negative electrode material, the first separator raw material, the positive electrode, and the second separator raw material in sequence; the process (B) is a process for cutting the laminate, and process (A) includes a process (a1) of coating an adhesive material on the bonding surface of the negative electrode material and the separator raw material, in which the adhesive material is coated in a manner that the first coating part and the second coating part are alternately located in the length direction, wherein the first coating part has an area coated with the adhesive material with a unit area mass M1, and the second coating part has an area coated with the adhesive material with a unit area mass M2 (≥M1+0.02g / m 2 ) in an area coated with an adhesive material, in step (B), the laminate is cut within the range where the second coating portion is located, and the positive electrode is arranged at a position opposite to the first coating portion.

Description

Technical Field

[0001] The present invention relates to a laminate for a secondary battery, a method for producing the laminate for a secondary battery, a secondary battery, and a method for producing the secondary battery. Background Art

[0002] Secondary batteries, such as lithium-ion batteries, are compact and lightweight, have high energy density, and are capable of repeated charge and discharge, making them used in a wide range of applications. Secondary batteries typically consist of components such as a positive electrode, a negative electrode, and a separator that separates the positive and negative electrodes to prevent short circuits.

[0003] Known secondary battery structures include a stacked type, in which a positive electrode, a separator, and a negative electrode are alternately stacked, and a wound type, in which elongated positive electrodes, separators, and negative electrodes are stacked and rolled into concentric circles. In recent years, stacked secondary batteries have attracted significant attention due to their superior energy density, safety, quality, and durability.

[0004] Moreover, when manufacturing secondary batteries, what has been done is, for example, laminating a long strip of electrode raw material with a long strip of spacer raw material, cutting it into a desired length and making a secondary battery laminate. Here, in the manufacture of the secondary battery laminate, the bonding of battery components such as the bonding of electrode raw material and spacer raw material is carried out by, for example, manufacturing a battery component with an adhesive material on the surface and laminating the battery component with other battery components. Moreover, the battery component with an adhesive material on the surface can be made by the following steps: dispersing and / or dissolving a polymer (binder) having adhesive properties in a solvent to form a secondary battery slurry, applying the secondary battery slurry to the surface of the battery component, and then drying (for example, see patent document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-27945. Summary of the Invention

[0008] Problems to be solved by the invention

[0009] Here, in the secondary battery laminate used for stacked type secondary batteries, it is required that the size of the separator and the negative electrode is larger than that of the positive electrode from the viewpoint of safety. Therefore, as a method for manufacturing the secondary battery laminate used for stacked type secondary batteries, for example, the following methods (1) to (4) can be considered (see Figure 4 ).

[0010] (1) After laminating long separator materials (first separator material 10A and second separator material 30A) on both sides of a long negative electrode material 20A, a previously cut positive electrode 40 is laminated on the surface of the first separator material 10A opposite to the negative electrode material 20A, and finally, a cutting machine 70 is used to cut the laminated body of the positive electrode 40, the first separator material 10A, the negative electrode material 20A, and the second separator material 30A (see Figure 4 (a)).

[0011] (2) A method in which a long separator material (a first separator material 10A and a second separator material 30A) is laminated to both sides of a long negative electrode material 20A, the laminate is cut using a cutting machine 70, and finally the pre-cut positive electrode 40 is laminated to the surface of the first separator 10 opposite to the negative electrode 20 side (see Figure 4 (b)).

[0012] (3) A method in which a long negative electrode raw material 20A, a long first separator raw material 10A, a pre-cut positive electrode 40, and a long second separator raw material 30A are sequentially laminated and then the laminated body of the second separator raw material 30A, the first separator raw material 10A, and the negative electrode raw material 20A is cut using a cutting machine 70 (see Figure 4 (c)).

[0013] (4) A method in which a long first separator raw material 10A and a long second separator raw material 30A are laminated with the previously cut negative electrode 20 interposed therebetween, the previously cut positive electrode 40 is laminated to the surface of the first separator raw material 10A opposite to the negative electrode 20, and finally the first separator raw material 10A and the second separator raw material 30A of the laminated body are cut using a cutting machine 70 (see Figure 4 (d)).

[0014] However, in the conventional method for producing a laminate for a secondary battery, when the separator material and the like are bonded together and then cut, the separator may peel off from the negative electrode at the cut portion and curl up.

[0015] Therefore, an object of the present invention is to provide a laminate for a secondary battery in which curling of a separator can be suppressed, and a secondary battery using the laminate for a secondary battery.

[0016] Solutions for solving problems

[0017] The present inventors conducted intensive research to achieve the above-mentioned object and found that curling of the separator during cutting can be suppressed by providing a predetermined distribution of the amount of the adhesive within the bonding surface between the negative electrode and the separator, thereby completing the present invention.

[0018] That is, the object of the present invention is to advantageously solve the above-mentioned problems. The secondary battery stack of the present invention is characterized in that it comprises: a negative electrode, a first separator attached to one surface of the negative electrode, a positive electrode attached to the surface of the first separator opposite to the negative electrode, and a second separator attached to the other surface of the negative electrode or the surface of the positive electrode opposite to the first separator. The size of the positive electrode when viewed from above is smaller than the size of the negative electrode, the first separator and the second separator when viewed from above. The negative electrode has a first edge and a second edge opposite to each other in a direction perpendicular to the stacking direction when viewed from above. When viewed from the stacking direction, the positive electrode is located between the first edge and the second edge. Between the second edges, the bonding surface of the negative electrode and the separator bonded to the negative electrode includes a projected portion where the positive electrode is projected when the positive electrode is projected in the stacking direction, and a non-projected portion where the positive electrode is not projected, the non-projected portion includes a first non-projected portion located closer to the first edge than the projected portion, and a second non-projected portion located closer to the second edge than the projected portion, the projected portion, the first non-projected portion, and the second non-projected portion each include a coated area coated with an adhesive material, and the unit area mass of the coated areas of the first non-projected portion and the second non-projected portion is greater than the unit area mass of the coated area of ​​the projected portion by 0.02 g / m 2 Thus, the unit area mass of the coating area of ​​the first non-projection part and the second non-projection part is greater than the unit area mass of the coating area of ​​the projection part by 0.02 g / m 2 The above-described laminate for a secondary battery can suppress the separator from peeling off from the negative electrode and curling up during production.

[0019] In the secondary battery stack of the present invention, the adhesive is preferably not applied to the edge portion extending along the first edge and the edge portion extending along the second edge in the non-projected portion. A secondary battery stack that is not applied to the edge portion extending along the first edge and the edge portion extending along the second edge can suppress adhesion of the adhesive to a cutting tool used during manufacturing and can be manufactured efficiently.

[0020] In addition, the secondary battery stack of the present invention is preferably not coated with an adhesive material in the non-projected portion, in a range of 1000 μm from the first edge, and in a range of 1000 μm from the second edge. The secondary battery stack not coated with an adhesive material in a range of 1000 μm from the first edge and in a range of 1000 μm from the second edge can suppress adhesion of the adhesive material to the cutting tool used during manufacturing and can be manufactured efficiently.

[0021] Furthermore, the secondary battery laminate of the present invention preferably has a mass per unit area of ​​the coated region of the projected portion of 0.01 g / m 2 Above and 3.00g / m 2 If the unit area mass of the coating area of ​​the projection part is 0.01g / m 2 Above and 3.00g / m 2 If the amount is less than 10%, it is possible to suppress an increase in the internal resistance of a secondary battery using the secondary battery laminate while ensuring sufficient adhesive strength.

[0022] Furthermore, the present invention aims to advantageously solve the above-mentioned problems. The secondary battery of the present invention is characterized by comprising any of the aforementioned secondary battery stacks. When the aforementioned secondary battery stacks are used, the secondary battery can exhibit excellent battery performance.

[0023] Furthermore, the purpose of the present invention is to advantageously solve the above-mentioned problems. The method for manufacturing a stack for a secondary battery of the present invention is characterized in that it is a method for manufacturing a stack for a secondary battery, wherein the stack for a secondary battery comprises: a negative electrode, a first separator attached to a surface of one side of the negative electrode, a positive electrode attached to a surface of the first separator opposite to the negative electrode, and a second separator attached to the other surface of the negative electrode or the surface of the positive electrode opposite to the first separator. The size of the positive electrode when viewed from above is smaller than the size of the negative electrode, the first separator, and the second separator when viewed from above. The method for manufacturing the stack for a secondary battery comprises the following steps: a step (A) of preparing a laminate and a step (B) of cutting the laminate, wherein the laminate has a negative electrode material composed of a long strip of negative electrode raw material or a negative electrode. , a long first separator raw material attached to one side surface of the above-mentioned negative electrode material, and a long second separator raw material attached to the other side surface of the above-mentioned negative electrode material, or the above-mentioned laminated body is formed by laminating the negative electrode material composed of a long negative electrode raw material, the long first separator raw material, the positive electrode and the long second separator raw material in sequence, the above-mentioned step (A) includes a step (a1) of coating the bonding material on the bonding surface of the above-mentioned negative electrode material and the separator raw material attached to the above-mentioned negative electrode material, in the above-mentioned step (a1), the above-mentioned bonding material is coated in a manner that the first coating part and the second coating part are alternately located in the longitudinal direction of the above-mentioned laminated body, the above-mentioned first coating part has an area coated with the bonding material with a unit area mass M1, and the above-mentioned second coating part has a bonding material with a mass per unit area greater than 0.02 g / m 2The above unit area mass M2 is applied to the area of ​​the adhesive material. In the above step (B), the above laminate is cut within the range where the above second coating portion is located. In the obtained secondary battery laminate, the above positive electrode is arranged at a position opposite to the above first coating portion. In this way, if the unit area mass M2 of the coating area of ​​the second coating portion is greater than the unit area mass M1 of the coating area of ​​the first coating portion located at a position opposite to the positive electrode by 0.02 g / m 2 As described above, by cutting the laminated body within the region where the second coating portion is located, the separator can be prevented from peeling off from the negative electrode and curling up at the cut portion.

[0024] Here, in the method for producing the secondary battery laminate of the present invention, it is preferable to apply the adhesive material using an inkjet method. If the inkjet method is used, the adhesive material can be easily applied to a desired area while changing the basis weight.

[0025] Furthermore, in the method for producing a secondary battery laminate of the present invention, it is preferred that the portion of the laminate extending along the cut position in step (B) above is not coated with an adhesive. If the portion extending along the cut position is not coated with an adhesive, adhesion of the adhesive to the cutting tool when the laminate is cut can be suppressed, thereby efficiently producing the secondary battery laminate.

[0026] Furthermore, in the method for producing a secondary battery laminate of the present invention, the laminate is preferably not coated with adhesive material in an area extending from the cut position in step (B) to 1000 μm on either side in the longitudinal direction. If no adhesive material is applied in an area extending from the cut position to 1000 μm on either side in the longitudinal direction, adhesion of the adhesive material to the cutting tool when the laminate is cut can be suppressed, allowing for efficient production of the secondary battery laminate.

[0027] Furthermore, in the method for producing a secondary battery laminate of the present invention, it is preferable that the mass per unit area M1 is 0.01 g / m 2 Above and 3.00g / m 2 If the mass per unit area is 0.01g / m 2 Above and 3.00g / m 2 If the amount is less than 10%, it is possible to suppress an increase in the internal resistance of a secondary battery using the secondary battery laminate while ensuring sufficient adhesive strength.

[0028] Furthermore, the present invention aims to advantageously address the aforementioned issues. The method for manufacturing a secondary battery of the present invention is characterized by comprising the following steps: manufacturing a plurality of secondary battery stacks using the aforementioned method for manufacturing a secondary battery stack; stacking the resulting secondary battery stacks to form a stack; and housing the stack in a battery container. Thus, using the secondary battery stacks manufactured using the aforementioned method for manufacturing a secondary battery stack enables the manufacture of a secondary battery that exhibits excellent battery performance.

[0029] Effects of the Invention

[0030] According to the present invention, a laminate for a secondary battery in which curling of a separator can be suppressed can be obtained.

[0031] Furthermore, according to the present invention, a secondary battery capable of exhibiting excellent battery performance can be obtained using the laminate for a secondary battery in which curling of the separator is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 (a) is a front view showing the structure of an example of a laminate for a secondary battery, Figure 1 (b) is an explanation Figure 1 (a) is a plan view showing the positional relationship between the negative electrode and the positive electrode of the secondary battery stack.

[0033] Figure 2 This is a front view showing the structure of an example of a stacked body obtained by stacking stacked bodies for secondary batteries.

[0034] Figure 3 It is a front view showing the structure of another example of the laminate for secondary batteries.

[0035] Figure 4 (a) to (d) are explanatory diagrams showing an example of a process for producing a laminate for a secondary battery.

[0036] Figure 5 It is a plan view showing an example of the bonding surface of the bonded body to which the adhesive material is applied.

[0037] Figure 6 (a) and Figure 6 (b) is a plan view showing another example of the bonding surface of the bonded body to which the adhesive material is applied.

[0038] Figure 7 (a) to (c) are plan views showing examples of the bonding surface of the negative electrode and the separator to which the adhesive material is applied.

[0039] Figure 8 It is an explanatory diagram showing the production process of the laminate for secondary batteries in Examples and Comparative Examples. DETAILED DESCRIPTION

[0040] Hereinafter, the secondary battery laminate and the method for producing the secondary battery laminate of the present invention will be described with reference to the accompanying drawings. In addition, for easier understanding, the dimensions of some components are shown exaggerated or reduced in each drawing.

[0041] The method for producing the secondary battery stack of the present invention can be used to produce the secondary battery stack of the present invention. Furthermore, the secondary battery of the present invention is characterized by using the secondary battery stack of the present invention and can be produced using, for example, the method for producing the secondary battery of the present invention.

[0042] Furthermore, the secondary battery stack obtained by using the secondary battery stack of the present invention and the method for producing the secondary battery stack of the present invention has, for example, Figure 1 The structure shown, or Figure 3 The structure shown in FIG. Moreover, the secondary battery stack can be, for example, Figure 2 The stacked bodies 200 are stacked as shown and used in laminated secondary batteries and the like.

[0043] Here, in Figure 1 The secondary battery stack 100 shown in the front view in (a) comprises: a negative electrode 20, and a laminated body ( Figure 1 The first separator 10 (upper side in the figure) is attached to the surface of the first separator 10, and the side opposite to the negative electrode 20 ( Figure 1 The positive electrode 40 is provided on the surface (upper side in the figure), and the second separator 30 is attached to the other side surface of the negative electrode 20. In addition, in this example, the first separator 10, the negative electrode 20, the second separator 30, and the positive electrode 40 are rectangular when viewed from above. Moreover, the negative electrode 20 has a structure in which negative electrode composite material layers 22 and 23 containing negative electrode active materials are formed on both sides of the negative electrode current collector 21, and the positive electrode 40 has a structure in which positive electrode composite material layers 42 and 43 containing positive electrode active materials are formed on both sides of the positive electrode current collector 41. In addition, the size of the positive electrode 40 when viewed from above is smaller than the size of the negative electrode 20, the first separator 10, and the second separator 30, as shown in FIG. Figure 1 As shown in the positional relationship between the negative electrode 20 and the positive electrode 40 in the plan view of FIG. 2 (b), the positive electrode 40 is located in the direction perpendicular to the stacking direction of the negative electrode 20 ( Figure 1 (b) between the first edge 24 and the second edge 25 that are opposite to each other in the left-right direction) and between the first edge 24 and the second edge 25 that are perpendicular to each other. Figure 1 (b) between the third edge 26 and the fourth edge 27 extending in the left-right direction.

[0044] In addition, Figure 3The secondary battery stack 100A shown in the front view has the second separator 30 attached to the side of the positive electrode 40 opposite to the first separator 10 side ( Figure 3 Instead of being attached to the other side surface of the negative electrode 20, it has the same Figure 1 The secondary battery stack 100 shown has the same structure.

[0045] In addition, the secondary battery laminated body obtained by using the secondary battery laminated body of the present invention and the method for producing the secondary battery laminated body of the present invention is not limited to Figure 1 and Figure 3 For example, the dimensions of the first separator 10 and the second separator 30 in the secondary battery stack in a plan view may be larger than the dimensions of the negative electrode 20. Using a secondary battery stack in which the first separator 10 and the second separator 30 are larger than the negative electrode 20 can further increase the safety margin for preventing short circuits when electrode misalignment occurs in the secondary battery.

[0046] Hereinafter, the method for producing a laminate for a secondary battery, the method for producing a secondary battery, the laminate for a secondary battery, and the secondary battery of the present invention will be described in order.

[0047] (Method for producing a laminate for a secondary battery)

[0048] The method for manufacturing a laminate for a secondary battery of the present invention includes a step (A) of preparing a laminate and a step (B) of cutting the laminate. When the laminate prepared by step (A) does not have a positive electrode, it optionally also includes a step (C) of laminating a positive electrode to a cut body obtained by cutting the laminate in step (B).

[0049] <Process (A)>

[0050] Here, examples of the bonded body produced in step (A) include the following (I) and (II).

[0051] (I) A negative electrode material comprising a long strip of negative electrode raw material or a negative electrode, a long strip of a first separator raw material adhered to the surface of one side of the negative electrode material, and a long strip of a second separator raw material adhered to the surface of the other side of the negative electrode material; optionally, a positive electrode adhered to the surface of the first separator raw material on the side opposite to the negative electrode material (hereinafter referred to as "the bonded body (I)").

[0052] (II) A laminated body formed by laminating a negative electrode material composed of a long negative electrode material, a long first separator material, a positive electrode, and a long second separator material in this order (hereinafter referred to as "laminated body (II)")

[0053] Furthermore, in the method for producing a laminate for a secondary battery of the present invention, when a laminate (I) is prepared in step (A), a laminate such as Figure 1 The secondary battery laminate shown includes a negative electrode, a first separator attached to one surface of the negative electrode, a positive electrode attached to the surface of the first separator opposite to the negative electrode, and a second separator attached to the other surface of the negative electrode.

[0054] When the laminate (I) does not have a positive electrode, the laminate for a secondary battery is usually produced by carrying out step (C) after step (B) in the method for producing the laminate for a secondary battery of the present invention.

[0055] In the method for producing a laminate for a secondary battery of the present invention, when a laminate (II) is prepared in step (A), a laminate such as Figure 3 The secondary battery stack shown has a negative electrode, a first separator attached to one surface of the negative electrode, a positive electrode attached to the surface of the first separator opposite to the negative electrode, and a second separator attached to the surface of the positive electrode opposite to the first separator.

[0056] The preparation of the bonded body in step (A) is generally performed by applying an adhesive to the bonding surfaces of the components to be bonded together, and bonding the components constituting the bonded body together via the adhesive. Specifically, step (A) includes step (a1) of applying the adhesive to the bonding surfaces of the negative electrode material and the separator material bonded to the negative electrode material, and step (a2) of applying the adhesive to the bonding surfaces of the separator material and the positive electrode.

[0057] In addition, the "separator material bonded to the negative electrode material" refers to the first separator material and the second separator material when the bonded body to be prepared is bonded body (I), and refers to the first separator material when the bonded body to be prepared is bonded body (II). Furthermore, the member to which the adhesive material is applied may be only one of the members or both of the members bonded to each other.

[0058] Specifically, in step (A), for example, Figure 4 The conjugate (I) is prepared as shown in (a), (b) or (d).

[0059] In step (A), for example, Figure 4 (c) Prepare the composite body (II).

[0060] Here, in Figure 4In (a), a long first separator material 10A fed from a first separator material roll is bonded to one side of a negative electrode material formed from a long negative electrode material 20A fed from a negative electrode material roll via an adhesive supplied from a coating machine 51, and a long second separator material 30A fed from a second separator material roll is bonded to the other side of a negative electrode material formed from the negative electrode material 20A via an adhesive supplied from a coating machine 52. Bonding can be performed using, for example, press rollers 61 and 62. Then, a positive electrode 40 is bonded to the surface of the first separator material 10A opposite to the negative electrode material 20A side via an adhesive supplied from a coating machine 53 at a predetermined spacing, thereby obtaining a bonded body (I) having a positive electrode.

[0061] In addition Figure 4 In (a), an adhesive material is supplied from a coating machine 54 to the surface of the second separator raw material 30A on the side opposite to the negative electrode raw material 20A, so that the secondary battery stacks can be well bonded to each other when the stacks are overlapped to produce a stack, wherein the stack is obtained by cutting the laminate between the positive electrodes 40 adjacent in the length direction.

[0062] In addition Figure 4 In (b), a long first separator material 10A fed from a first separator material roll is bonded to one surface of the negative electrode material formed from a long negative electrode material 20A fed from a negative electrode material roll via an adhesive supplied from a coating machine 51, and a long second separator material 30A fed from a second separator material roll is bonded to the other surface of the negative electrode material formed from the negative electrode material 20A via an adhesive supplied from a coating machine 52, thereby obtaining a bonded body (I) without a positive electrode. For example, bonding rollers 61 and 62 can be used for bonding.

[0063] In addition Figure 4 In (b), after the laminate is cut, the positive electrode 40 is bonded to the obtained cut body via the adhesive material supplied from the coating machine 53 (step (C)). Figure 4 In (b), the adhesive is supplied from the coating machine 54 to the surface of the cut body opposite to the positive electrode 40 side, so that the secondary battery stacks obtained by laminating the cut bodies with the positive electrodes can be well bonded to each other when the stack is stacked to produce a stack.

[0064] Then in Figure 4In (c), a long first separator material 10A fed from a first separator material roll is bonded to the surface of the negative electrode material side of the long negative electrode material 20A fed from the negative electrode material roll via an adhesive supplied from a coating machine 51. Furthermore, a positive electrode 40 is bonded to the surface of the first separator material 10A opposite to the negative electrode material 20A side via an adhesive supplied from a coating machine 52. Furthermore, a long second separator material 30A fed from a second separator material roll is bonded to the surfaces of the first separator material 10A and the positive electrode 40 opposite to the negative electrode material 20A side via an adhesive supplied from a coating machine 53, thereby obtaining a bonded body (II). For example, bonding rollers 61 and 62 can be used for bonding.

[0065] In addition Figure 4 In (c), the adhesive material is supplied from the coating machine 54 to the surface of the negative electrode material 20A opposite to the first separator material 10A side, so that the secondary battery stacks obtained by cutting the laminated bodies are stacked to make a stacked body, so that the secondary battery stacks can be well bonded to each other.

[0066] Then in Figure 4 In (d), the negative electrode material formed of the negative electrode 20 is bonded to one surface of the long second separator raw material 30A fed from the second separator raw material roll at a predetermined spacing via the adhesive material supplied from the coating machine 52, and the long first separator raw material 10A fed from the first separator raw material is bonded to one surface of the negative electrode material formed of the negative electrode 20 and the second separator raw material 30A via the adhesive material supplied from the coating machine 51, thereby obtaining a bonded body (I) without a positive electrode. Here, bonding can be performed using, for example, pressure bonding rollers 61 and 62.

[0067] In addition, Figure 4 In (d), after the laminate is cut, the positive electrode 40 is bonded to the obtained cut body via the adhesive material supplied from the coating machine 53 (step (C)). Figure 4 In (d), the adhesive material is supplied from the coating machine 54 to the surface of the second separator material 30A opposite to the negative electrode 20 side, so that the secondary battery stacks obtained by laminating the cut bodies to the positive electrodes can be well bonded to each other when the stack is stacked to produce a stack.

[0068] In addition, the method for preparing the bonded body in step (A) is not limited to the above examples. Figure 4 In (a), (c) and (d), the adhesive material may be supplied from the coating machine 54 to the cut body obtained after the laminate is cut. Figure 4In (d), the positive electrode 40 may be bonded to the surface of the first separator material 10A opposite to the negative electrode 20 side at a predetermined arrangement pitch via an adhesive supplied from the coater 53 to obtain a bonded body (I) having a positive electrode.

[0069] [Anode materials and cathode]

[0070] Here, as an electrode (negative electrode or positive electrode), it is not particularly limited, and it is possible to use, for example, an electrode obtained by cutting a long strip of electrode raw material (negative electrode raw material or positive electrode raw material). Moreover, as an electrode raw material (negative electrode raw material or positive electrode raw material), it is possible to use the following electrode raw materials: an electrode composite material layer (negative electrode composite material layer or positive electrode composite material layer) is formed on one or both sides of a long strip of current collector to obtain an electrode substrate, an electrode raw material formed by the electrode substrate; or an electrode raw material obtained by further forming a porous membrane layer on the electrode composite material layer of the electrode substrate.

[0071] In addition, as current collector, electrode composite material layer and porous film layer, there is no particular limitation, and any current collector, electrode composite material layer and porous film layer that can be used in the field of secondary batteries, such as the current collector, electrode composite material layer and porous film layer described in Japanese Patent Application Laid-Open No. 2013-145763, can be used. Here, porous film layer refers to a layer comprising non-conductive particles described in Japanese Patent Application Laid-Open No. 2013-145763.

[0072] [Spacer materials]

[0073] The separator material is not particularly limited, and for example, a separator material formed of a long separator substrate or a separator material obtained by forming a porous membrane layer on one or both surfaces of a long separator substrate can be used.

[0074] The separator substrate and the porous membrane layer are not particularly limited, and any separator substrate and porous membrane layer that can be used in the field of secondary batteries, such as those described in Japanese Patent Application Laid-Open Nos. 2012-204303 and 2013-145763, can be used.

[0075] [Adhesive material]

[0076] Furthermore, as long as the adhesive material does not hinder the battery reaction, there is no particular limitation, and any adhesive material that can be used in the field of secondary batteries can be used. Among them, as the adhesive material, an adhesive material formed of a polymer is preferably used. Furthermore, the polymer constituting the adhesive material may be only one type, or may be two or more types.

[0077] There are no particular limitations on the polymers that can be used as adhesives, and examples include: fluorine-based polymers such as polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) copolymers; conjugated diene polymers such as styrene-butadiene copolymers (SBR) and acrylonitrile-butadiene copolymers (NBR); hydrogenated products of conjugated diene polymers; polymers containing (meth) alkyl acrylate monomer units (acrylic polymers); polyvinyl alcohol polymers such as polyvinyl alcohol (PVA), and the like.

[0078] In the present invention, "(meth)acrylic acid" means acrylic acid and / or methacrylic acid.

[0079] Furthermore, the shape of the adhesive material formed of a polymer is not particularly limited, and may be granular, non-granular, or a combination of granular and non-granular forms.

[0080] In addition, when the adhesive material formed by the polymer is granular, the granular adhesive material can be a particle of a single phase structure formed by a single polymer, or a particle of a heterogeneous structure formed by physically or chemically combining two or more different polymers. Here, as a specific example of a heterogeneous structure, there can be cited: a core-shell structure formed by a polymer different from the center (core) and the outer shell (shell) in a spherical particle; a side-by-side structure in which two or more polymers are placed side by side, etc. In addition, in the "core-shell structure" of the present invention, in addition to the structure in which the shell completely covers the outer surface of the core, a structure in which the shell partially covers the outer surface of the core is also included. Moreover, in the present invention, even if it appears that the outer surface of the core is completely covered by the shell, as long as a hole connecting the inside and outside of the shell is formed, the shell is a shell that partially covers the outer surface of the core.

[0081] The adhesive material may be supplied to the bonding surface in any state, such as a solid state, a molten state, a state dissolved in a solvent, or a state dispersed in a solvent. The adhesive material is preferably supplied in a state dissolved in a solvent or dispersed in a solvent, and more preferably supplied in a state dispersed in a solvent.

[0082] Furthermore, when the adhesive material is supplied to the bonding surface in a dissolved or dispersed state in a solvent, that is, when an adhesive composition comprising the adhesive material and a solvent is supplied to the bonding surface, the solvent in the adhesive composition is not particularly limited, and examples thereof include water, organic solvents, and mixtures thereof. Furthermore, the organic solvent is not particularly limited, and examples thereof include: alicyclic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, γ-butyrolactone, and ε-caprolactone; nitriles such as acetonitrile and propionitrile; ethers such as tetrahydrofuran and ethylene glycol diethyl ether; and alcohols such as methanol, ethanol, isopropyl alcohol, ethylene glycol, and ethylene glycol monomethyl ether.

[0083] Among the above, from the viewpoint of efficiently producing a laminate for a secondary battery, water and alcohol are preferred as the solvent, and water is more preferred.

[0084] The adhesive material can be applied using a coating machine using a known coating method such as an inkjet method, a spray method, a dispenser method, a gravure coating method, or a screen printing method. Among them, the adhesive material is preferably applied using an inkjet method because the amount and range of the applied adhesive material can be easily adjusted.

[0085] Moreover, the adhesive material can be applied to the entire surface of the bonding surface, or it can be applied only to a part of the bonding surface. Here, in the case where the adhesive material is applied only to a part of the bonding surface, the adhesive material can be applied to any top-view shape such as strips, dots, or grids without any particular limitation. Among them, from the viewpoint of improving the liquid injection of the electrolyte when the secondary battery is manufactured using the secondary battery laminate, it is preferred that the adhesive material is applied in a dotted shape. Moreover, the dotted adhesive material can be evenly configured (applied) on the entire surface of the bonding surface, or it can be arranged (applied) into a prescribed pattern such as strips, dots, or grids. In addition, when the tiny dotted adhesive material is arranged into a prescribed pattern, from the viewpoint of easily applying and arranging the adhesive material, the adhesive material is preferably applied by an inkjet method.

[0086] The cross-sectional shape of the adhesive is not particularly limited and can be convex, concave-convex, or concave, with concave-convex being preferred. The cross-sectional shape of the adhesive can be changed, for example, by adjusting the drying conditions when applying the adhesive.

[0087] [Step (a1)]

[0088] Then, in the step (a1) of applying the adhesive material to the bonding surface of the negative electrode material and the separator raw material bonded to the negative electrode material, the adhesive material needs to be applied in a manner that the first coating portion and the second coating portion are alternately located in the longitudinal direction of the bonded body, the first coating portion having an area coated with the adhesive material at a unit area mass M1, and the second coating portion having an area coated with the adhesive material at a mass per unit area greater than 0.02 g / m 2 The above mass per unit area M2 is the area coated with the adhesive material.

[0089] -First coating section-

[0090] Here, the first coating portion is the portion corresponding to the position of the positive electrode in the secondary battery laminate produced using the laminate. That is, in the secondary battery laminate produced according to the method for producing a secondary battery laminate of the present invention, the portion (projected portion) where the positive electrode is projected when the positive electrode is projected in the stacking direction is the first coating portion. Furthermore, the first coating portion has an area (coated area) coated with an adhesive material at a mass per unit area M1.

[0091] In addition, the coating area of ​​the first coating portion may be the entire first coating portion or a portion of the first coating portion.

[0092] Furthermore, the mass per unit area M1 of the coating region of the first coating portion is preferably 0.01 g / m 2 Above and 3.00g / m 2 Below, more preferably 0.01g / m 2 Above and 0.20g / m 2 Below, more preferably 0.01g / m 2 Above 0.05g / m 2 If the mass per unit area M1 is above the lower limit, the negative electrode material and the separator material can be well bonded. If the mass per unit area M1 is below the upper limit, the internal resistance of the secondary battery can be suppressed and the electrolyte injection property can be improved.

[0093] Furthermore, when the adhesive material is applied in a dotted pattern, the average thickness of the dots formed in the coated area of ​​the first coating portion is preferably 0.2 μm to 3.0 μm. If the average thickness of the dots is above this lower limit, good adhesion between the negative electrode material and the separator material can be achieved. Furthermore, if the average thickness of the dots is below this upper limit, an increase in the internal resistance of the secondary battery can be suppressed.

[0094] Furthermore, when the adhesive material is applied in a dotted shape, the arrangement spacing of the dots formed in the coating area of ​​the first coating portion (the distance between the centers of the dots when viewed from above) is preferably 100 μm or more and 1000 μm or less, more preferably 200 μm or more and 700 μm or less. If the arrangement spacing of the dots is above the above lower limit, the internal resistance of the secondary battery can be suppressed and the injection property of the electrolyte can be improved. If the arrangement spacing of the dots is below the above upper limit, the negative electrode material and the separator raw material can be well bonded.

[0095] -Second coating section-

[0096] The second coating portion is located between adjacent first coating portions in the length direction of the laminate. Furthermore, the laminate is typically cut within the range of the second coating portion. Furthermore, the second coating portion includes an area (coating area) coated with adhesive material at a mass per unit area M2.

[0097] In addition, the coating area of ​​the second coating portion may be the entire second coating portion or a portion of the second coating portion.

[0098] Furthermore, the mass per unit area M2 of the coating area of ​​the second coating portion needs to be greater than the mass per unit area M1 of the coating area of ​​the first coating portion by 0.02 g / m 2 The difference (M2-M1) between the mass per unit area M2 and the mass per unit area M1 is preferably 0.10 g / m 2 More than 0.20 g / m 2 Above, preferably 0.50g / m 2 Below, more preferably 0.25g / m 2 If the difference between the mass per unit area M2 and the mass per unit area M1 (M2-M1) is not less than 0.02 g / m 2 If the difference (M2 - M1) between the mass per unit area M2 and the mass per unit area M1 is within the above range, curling of the separator during cutting can be sufficiently suppressed, thereby suppressing an increase in the internal resistance of the secondary battery.

[0099] Furthermore, when the adhesive material is applied in dot form, the average thickness of the dots formed in the coating region of the second coating portion is preferably 0.2 μm or greater, and more preferably 0.5 μm or less. If the average thickness of the dots is at least the lower limit, curling of the separator during cutting can be sufficiently suppressed.

[0100] Furthermore, when the adhesive material is applied in a dotted pattern, the spacing of the dots formed in the coating area of ​​the second coating portion (the distance between the centers of the dots when viewed from above) is preferably from 100 μm to 500 μm, more preferably from 100 μm to 200 μm. If the dot spacing is below the upper limit, curling of the separator during cutting can be sufficiently suppressed.

[0101] Furthermore, the shapes and ranges of the coating regions of the first coating portion and the second coating portion are not particularly limited and can be, for example, Figure 5 and Figure 6 Shape and range shown.

[0102] Here, Figure 5 The bonding surface 80 shown is in the shape of a long rectangle, and the first coating portion 81 and the second coating portion 82 are in the length direction ( Figure 5 The left and right directions in the image are set alternately.

[0103] Furthermore, the coating area 81A of the first coating portion 81 is provided in the entire first coating portion (the portion where the entire positive electrode is projected when the positive electrode is projected in the stacking direction). Figure 5 Although the adhesive material is not applied to the portions on both sides of the first coating portion 81 in the up-down direction (in the vertical direction), any amount of adhesive material may be applied to these portions.

[0104] The coating region 82A of the second coating section 82 is provided over the entire second coating section (the entire widthwise region of the bonding surface 80 between the first coating sections 81 ) including the cutting position 83 in the step (B) described later.

[0105] If the coating region 82A is provided over the entire second coating portion 82 in this manner, curling of the separator during cutting can be sufficiently suppressed.

[0106] also, Figure 6 The bonding surface 80 shown in (a) has the same characteristics as the bonding surface 80 except that the range of the coating area 82A of the second coating portion 82 is different. Figure 5 The bonding surfaces shown are of the same morphology.

[0107] Here, Figure 6 The coating area 82A of the second coating portion 82 of the bonding surface 80 shown in (a) is provided on both sides of the bonding surface 80 in the longitudinal direction sandwiching the cutting position 83, and covers the entire width direction of the bonding surface 80. Figure 6 In the second coating portion 82 of the bonding surface 80 shown in (a), the adhesive material is not applied to a portion 82B extending along the cut position.

[0108] If the adhesive material is not applied to the portion 82B extending along the cutting position in this manner, it is possible to prevent the adhesive material from adhering to the cutting tool used for cutting and shortening the life of the cutting tool.

[0109] In addition, from the perspective of suppressing the adhesion of the adhesive material to the cutting tool and fully suppressing the curling of the spacer during cutting, the range where the adhesive material is not applied is preferably within the range from the cutting position 83 to 1000 μm on both sides in the longitudinal direction, and more preferably within the range from the cutting position 83 to 200 μm on both sides in the longitudinal direction.

[0110] and then, Figure 6 The bonding surface 80 shown in (b) has the same characteristics as the bonding surface 80 except that the range of the coating area 82A in the width direction of the bonding surface 80 is different. Figure 6 (a) shows the same bonding surface.

[0111] Here, Figure 6 The coating area 82A of the second coating portion 82 of the bonding surface 80 shown in (b) is provided at both ends of the bonding surface 80 in the width direction on both sides of the bonding surface 80 in the length direction sandwiching the cutting position 83. Figure 6 In the second coating portion 82 of the bonding surface 80 shown in (b), the adhesive material is not applied to the portion 82B extending along the cut position, and only the coating areas 82A are provided at the four corners of the second coating portion 82 .

[0112] If the adhesive material is not applied to the portion 82B extending along the cutting position in this manner, it is possible to prevent the adhesive material from adhering to the cutting tool used for cutting and shortening the life of the cutting tool.

[0113] In addition, from the perspective of suppressing the adhesion of the adhesive material to the cutting tool and fully suppressing the curling of the spacer during cutting, the range where the adhesive material is not applied is preferably within the range from the cutting position 83 to 1000 μm on both sides in the longitudinal direction, and more preferably within the range from the cutting position 83 to 200 μm on both sides in the longitudinal direction.

[0114] In the above, from the viewpoint of suppressing the adhesion of the adhesive material to the cutting tool and sufficiently suppressing the curling of the spacer during cutting, the shapes and ranges of the coating areas of the first coating portion and the second coating portion are preferably as follows: Figure 6 (a) or Figure 6 (b) The shape and range shown.

[0115] [Step (a2)]

[0116] In the step (a2) which can be optionally performed, an adhesive material is applied to the bonding surface of the separator material and the positive electrode.

[0117] Specifically, in the case of preparing a laminate having a positive electrode in step (A) (for example, see Figure 4 (a) and Figure 4 (c)), and in the case where a laminated body (laminated body without a positive electrode) is prepared in step (A) with an adhesive material applied in advance to the position where the positive electrode is laminated after cutting (for example, see Figure 4 (d) In step (a2), an adhesive is applied to the bonding surface of the separator material and the positive electrode.

[0118] That is, for example, Figure 4 In (a), the adhesive material is applied from the coating machine 53 to the bonding surface of the first separator material 10A and the positive electrode 40. Figure 4 In (c), the adhesive material is applied from the coating machine 52 and the coating machine 53 to the bonding surface of the first separator material 10A and the positive electrode 40 and the bonding surface of the second separator material 30A and the positive electrode 40. Figure 4 In (d), the surface of the first separator material 10A to be bonded to the positive electrode 40 after being cut is coated by the coating machine 53. Figure 4 (d) The upper side is coated with adhesive material.

[0119] Here, in process (a2), the shape and range of the coating area when the adhesive material is coated on the bonding surface of the separator raw material and the positive electrode can be any shape and range as long as the positive electrode and the separator raw material can be bonded. From the viewpoint of suppressing the adhesion of the adhesive material to the cutting tool used during cutting and shortening the life of the cutting tool, it is preferred that the adhesive material is not coated on the portion extending along the cutting position cut in process (B), more preferably, the adhesive material is not coated on the range from the cutting position to 1000 μm on both sides in the longitudinal direction, and further preferably, the adhesive material is not coated on the range from the cutting position to 200 μm on both sides in the longitudinal direction.

[0120] That is, the laminate prepared in process (A) is preferably not coated with adhesive material along the portion extending from the cut position cut in process (B), more preferably not coated with adhesive material from the cut position to a range of 1000 μm on both sides in the longitudinal direction, and further preferably not coated with adhesive material from the cut position to a range of 200 μm on both sides in the longitudinal direction.

[0121] Furthermore, from the perspective of facilitating the setting of the coating range of the coating machine, the shape and range of the coating area when applying the adhesive to the bonding surface of the separator material and the positive electrode is preferably the same as the shape and range of the coating area when applying the adhesive to the bonding surface of the negative electrode material and the separator material in step (a1). In other words, the shape and range of the coating area in step (a1) is preferably the same as the shape and range of the coating area in step (a2) when projected in the lamination direction, and furthermore, the weight per unit area of ​​the corresponding coating area is preferably the same in steps (a1) and (a2).

[0122] In addition, when preparing an adhesive body (II) having a portion where the separator raw materials are bonded to each other between the cutting position and the edge of the positive electrode 40 when viewed in the length direction of the bonded body, peeling between the separators can also be suppressed when the shape and range of the coating area of ​​process (a2) are made the same as the shape and range of the coating area of ​​process (a1).

[0123] In step (A), for example, Figure 4 As shown in (a), (c) and (d), it is also possible to apply a layer of adhesive to one side of the surface of the laminate (at Figure 4 (a) and (d) are the surfaces of the second separator material 30A on the side opposite to the negative electrode material (negative electrode material 20A, negative electrode 20). Figure 4 (c) The adhesive is applied to the surface of the negative electrode material 20A opposite to the first separator material 10A, thereby enabling the secondary battery stacks to be well bonded to each other when the stacks are stacked to form a stack. In this case, the shape and range of the coating area when the adhesive is applied to the surface of one side of the stack can be any shape and range as long as the secondary battery stacks can be bonded to each other. From the perspective of preventing the adhesive from adhering to the cutting tool used during cutting and shortening the life of the cutting tool, it is preferred that the adhesive is not applied to the portion extending along the cut position cut in step (B). It is more preferred that the adhesive is not applied to the area from the cut position to 1000 μm on both sides in the longitudinal direction. It is even more preferred that the adhesive is not applied to the area from the cut position to 200 μm on both sides in the longitudinal direction.

[0124] That is, the bonded body prepared in step (A) is preferably not coated with adhesive material along the portion extending from the cut position cut in step (B), more preferably not coated with adhesive material from the cut position to 1000 μm on both sides in the longitudinal direction, and further preferably not coated with adhesive material from the cut position to 200 μm on both sides in the longitudinal direction.

[0125] Furthermore, from the perspective of facilitating the setting of the coating range of the coating machine, the shape and range of the coating area when applying the adhesive material to the surface of one side of the laminated body are preferably the same as the shape and range of the coating area when applying the adhesive material to the bonding surface of the negative electrode material and the separator raw material in step (a1). In other words, the shape and range of the coating area in step (a1) are preferably identical to the shape and range of the coating area on the surface of one side of the laminated body when projected in the lamination direction, and the mass per unit area of ​​the corresponding coating area is preferably the same as that in step (a1).

[0126] <Process (B)>

[0127] In step (B), the cutter 70 is used to cut the laminate at the cutting position 83. When the laminate having the positive electrode is cut in step (B), the obtained cut body is a laminate for a secondary battery.

[0128] Here, as the cutter 70 , any cutter that can be used in the field of secondary battery production, such as a cutter that cuts the laminated body by sandwiching it from both sides in the thickness direction of the laminated body with a cutting blade, can be used.

[0129] Furthermore, in the step (B) performed after the step (A), as described above, the separator can be prevented from curling away from the negative electrode and the laminate can be cut satisfactorily.

[0130] In addition, cut Figure 5 The bonding surface 80 shown in FIG. Figure 7 As shown in (a), cut Figure 6 The bonding surface of the negative electrode and the separator obtained by bonding the surface 80 shown in (a) is as follows Figure 7 (b) shows, cut off Figure 6 The bonding surface of the negative electrode and the separator obtained by bonding the surface 80 shown in (b) is as follows Figure 7 (c) shown.

[0131] <Process (C)>

[0132] In the arbitrarily implemented step (C), when the laminated body without the positive electrode is cut in the step (B), the positive electrode is bonded to the cut body obtained by cutting the laminated body in the step (B) to obtain a laminate for a secondary battery.

[0133] When an adhesive is applied to the cut body after step (B) for laminating the positive electrode in step (C) and / or for good adhesion of the secondary battery stacks, the shape and range of the coated area can be arbitrary.

[0134] (Method for Manufacturing Secondary Battery)

[0135] The method for producing a secondary battery of the present invention includes the steps of producing a plurality of secondary battery stacks using the method for producing a secondary battery stack of the present invention, and assembling a secondary battery using the secondary battery stacks and an electrolyte solution (assembling step).

[0136] Furthermore, in the method for producing a secondary battery of the present invention, since the laminate for a secondary battery produced by the above-mentioned method is used, a secondary battery capable of exhibiting excellent battery performance can be obtained.

[0137] <Assembly Process>

[0138] Here, as the electrolyte, an organic electrolyte in which a supporting electrolyte is dissolved in an organic solvent can generally be used. For example, when the secondary battery is a lithium ion secondary battery, a lithium salt can be used as the supporting electrolyte. As lithium salts, for example, LiPF6, LiAsF6, LiBF4, LiSbF6, LiAlCl4, LiClO4, CF3SO3Li, C4F9SO3Li, CF3COOLi, (CF3CO)2NLi, (CF3SO2)2NLi, (C2F5SO2)NLi, etc. can be mentioned. Among them, because they are easily soluble in solvents and show a high degree of dissociation, LiPF6, LiClO4, CF3SO3Li are preferred, and LiPF6 is particularly preferred. In addition, the electrolyte can be used alone or in combination of two or more in any ratio. Generally, because the higher the degree of dissociation of the supporting electrolyte used, the higher the conductivity of the lithium ions, the higher the tendency, so the conductivity of the lithium ions can be adjusted according to the type of supporting electrolyte.

[0139] Furthermore, as an organic solvent used in the electrolyte, there is no particular limitation as long as it is an organic solvent that can dissolve the supporting electrolyte. For example, carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), ethyl methyl carbonate (EMC), and vinylene carbonate (VC) can be preferably used; esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as cyclopentane and dimethyl sulfoxide. In addition, a mixture of these solvents can also be used. Among them, carbonates are preferably used because of their high dielectric constant and wide stable potential range. Generally, since the lower the viscosity of the solvent used, the higher the conductivity of lithium ions, the conductivity of lithium ions can be adjusted according to the type of solvent.

[0140] In addition, the concentration of the electrolyte in the electrolytic solution can be adjusted appropriately. In addition, known additives can also be added to the electrolytic solution.

[0141] Moreover, the secondary battery can be assembled by the following steps: the secondary battery laminate manufactured according to the manufacturing method of the secondary battery laminate of the present invention is overlapped to obtain an overlapped body, and the overlapped body is further laminated with additional battery components (electrodes and / or spacers, etc.) as needed, and the obtained overlapped body is placed in a battery container, and an electrolyte is injected into the battery container and sealed. In addition, in order to prevent the internal pressure of the secondary battery from rising, overcharging and discharging, etc., anti-overcurrent elements such as fuses, PTC elements, metal mesh, guide plates, etc. can also be provided as needed. In addition, the shape of the secondary battery can be any shape such as coin type, button type, sheet type, cylindrical type, square type, flat type, etc.

[0142] (Laminate for secondary battery)

[0143] The secondary battery laminate of the present invention is manufactured using, for example, the above-mentioned method for manufacturing the secondary battery laminate of the present invention, such as Figure 1 or Figure 3 As shown, it has a negative electrode 20, a first separator 10 attached to one side surface of the negative electrode, a positive electrode 40 attached to the surface of the first separator 10 on the side opposite to the negative electrode 20, and a second separator 30 attached to the other side surface of the negative electrode 20 or the surface of the positive electrode 40 on the side opposite to the first separator 10.

[0144] In addition, the secondary battery laminate 100, 100A is as follows Figure 2 As shown, the dimensions of the positive electrode 40 when viewed from above are smaller than the dimensions of the negative electrode 20, the first separator 10, and the second separator 30 when viewed from above. Specifically, the negative electrode 20 of the secondary battery stack 100, 100A has a first edge 24 and a second edge 25 that face each other in a direction perpendicular to the stacking direction when viewed from above. When viewed from the stacking direction, the positive electrode 40 is located between the first edge 24 and the second edge 25. Furthermore, the first edge 24 and the second edge 25 generally correspond to the cutting positions when the long strip of negative electrode material is cut to form the negative electrode 20.

[0145] Furthermore, the bonding surface between the negative electrode 20 and the separator bonded to the negative electrode 20 is, for example, Figure 7As shown, there is a projection portion 81' on which the positive electrode 40 is projected when the positive electrode 40 is projected in the stacking direction, and a non-projection portion on which the positive electrode 40 is not projected. In addition, the non-projection portion has a first non-projection portion 82' located closer to the first edge 24 than the projection portion 81', and a second non-projection portion 82' located closer to the second edge 25 than the projection portion 81'. Furthermore, the projection portion 81', the first non-projection portion 82', and the second non-projection portion 82' respectively have a coating area coated with an adhesive material, and the unit area mass M2 of the coating area of ​​the first non-projection portion 82' and the second non-projection portion 82' is greater than the unit area mass M1 of the coating area of ​​the projection portion 81' by 0.02 g / m 2 above.

[0146] <Projection Department>

[0147] Here, the projected portion 81' is a portion where the positive electrode 40 is projected in the stacking direction of the secondary battery stack 100 or 100A. The projected portion 81' includes a region (coated region 81A) coated with an adhesive material having a mass per unit area M1.

[0148] In addition, the coating area 81A of the projection portion 81 ′ may be the entire projection portion or a portion of the projection portion 81 ′.

[0149] Furthermore, the mass per unit area M1 of the coating area of ​​the projection portion 81 ′ is preferably 0.01 g / m 2 Above and 3.00g / m 2 Below, more preferably 0.01g / m 2 Above and 0.20g / m 2 Below, more preferably 0.01g / m 2 Above and 0.05g / m 2 If the mass per unit area M1 is above the lower limit, the negative electrode material and the separator can be well bonded. If the mass per unit area M1 is below the upper limit, the internal resistance of the secondary battery can be suppressed and the electrolyte injection property can be improved.

[0150] Furthermore, when the adhesive material is applied in a dot-like pattern, the average thickness of the dots formed in the applied area of ​​the projected portion 81' is preferably 0.2 μm or greater and 3.0 μm or less. If the average thickness of the dots is above the lower limit, good adhesion between the negative electrode and the separator is achieved. If the average thickness of the dots is below the upper limit, an increase in the internal resistance of the secondary battery can be suppressed.

[0151] Furthermore, when the adhesive material is applied in a dotted pattern, the spacing between the dots formed in the applied area of ​​the projection portion 81' (the distance between the centers of the dots when viewed from above) is preferably 100 μm to 1000 μm, and more preferably 200 μm to 700 μm. If the dot spacing is above the lower limit, the internal resistance of the secondary battery can be suppressed and the electrolyte injection efficiency can be improved. Furthermore, if the dot spacing is below the upper limit, good adhesion between the negative electrode and the separator can be achieved.

[0152] <Non-projection area>

[0153] The non-projection portion is a portion surrounded by the outer peripheral edge of the negative electrode 20 and the outer peripheral edge of the projection portion 81', and includes a first non-projection portion 82' located closer to the first edge 24 than the projection portion 81', and a second non-projection portion 82" located closer to the second edge 25 than the projection portion 81'.

[0154] -First non-projected portion-

[0155] The first non-projection portion 82' is located between the projection portion 81' and the first edge 24. The first non-projection portion 82' has a region (coated region 82A) coated with the adhesive material at a mass per unit area M2.

[0156] In addition, the coating area 82A of the first non-projection portion 82 ′ may be the entire first non-projection portion 82 ′ or a portion of the first non-projection portion 82 ′.

[0157] -Second non-projected portion-

[0158] The second non-projection portion 82 ″ is located between the projection portion 81 ′ and the second edge 25 . The second non-projection portion 82 ″ includes a region (coated region 82A) coated with the adhesive material at a mass per unit area M2 .

[0159] In addition, the coating area 82A of the second non-projection portion 82 ″ may be the entire second non-projection portion 82 ″ or a portion of the second non-projection portion 82 ″.

[0160] Furthermore, the mass per unit area M2 of the coating area 82A of the first non-projection portion 82' and the second non-projection portion 82" needs to be greater than the mass per unit area M1 of the coating area 81A of the projection portion 81' by 0.02 g / m 2 The difference (M2-M1) between the mass per unit area M2 and the mass per unit area M1 is preferably 0.10 g / m 2 More than 0.20 g / m 2 , preferably 0.50g / m 2 Below, more preferably 0.25g / m2 If the difference between the mass per unit area M2 and the mass per unit area M1 (M2-M1) is not less than 0.02 g / m 2 If the difference (M2 - M1) between the mass per unit area M2 and the mass per unit area M1 is within the above range, the curling of the separator can be sufficiently suppressed, and the internal resistance of the secondary battery can be suppressed.

[0161] Furthermore, when the adhesive material is applied in a dotted form, the average thickness of the dots formed in the coating region 82A of the first non-projection portion 82' and the second non-projection portion 82" is preferably 0.2 μm or more, more preferably 0.5 μm or more. If the average thickness of the dots is greater than or equal to the above lower limit, curling of the spacer can be sufficiently suppressed.

[0162] Furthermore, when the adhesive material is applied in a dotted form, the arrangement spacing of the dots formed in the coating area 82A of the first non-projection portion 82' and the second non-projection portion 82" (the distance between the centers of the dots when viewed from above) is preferably greater than 100 μm and less than 500 μm, and more preferably greater than 100 μm and less than 200 μm. If the arrangement spacing of the dots is below the above-mentioned upper limit value, curling of the spacer can be sufficiently suppressed.

[0163] Furthermore, the shape and range of the coating area 82A of the first non-projection portion 82' and the second non-projection portion 82" are not particularly limited and can be, for example, Figure 7 The shapes and ranges shown in (a) to (c).

[0164] Here, Figure 7 The bonding surface 80A shown in (a) is rectangular, and the coating area 81A of the projection portion 81' is set to the entire projection portion (the portion where the entire positive electrode is projected when the positive electrode is projected in the stacking direction). In addition, in the example shown in the figure, although the coating area 81A of the bonding surface 80A is set to the entire projection portion Figure 7 Although the adhesive material is not applied to both side portions of the vertical projection portion 81 ′ in (a), any amount of adhesive material may be applied to these portions.

[0165] Furthermore, the coating area 82A of the first non-projection portion 82 ′ and the second non-projection portion 82 ″ is provided to the entire first non-projection portion and the entire second non-projection portion.

[0166] also, Figure 7 The laminating surface 80A shown in (b) has the same characteristics as the laminating surface 80A except that the range of the coating area 82A of the first non-projection portion 82' and the second non-projection portion 82" is different. Figure 7 (a) shows the same bonding surface.

[0167] Here, in Figure 7 In the first non-projected portion 82 ′ and the second non-projected portion 82 ″ of the bonding surface 80A shown in (b), the adhesive material is not applied to the portion 82B extending along the first edge 24 and the portion 82B extending along the second edge 25 .

[0168] If the adhesive is not applied to the portion 82B extending along the first edge 24 and the second edge 25 in this manner, it is possible to prevent the adhesive from adhering to the cutting tool used for cutting and shortening the life of the cutting tool.

[0169] In addition, from the perspective of suppressing the adhesion of the adhesive material to the cutting tool and fully suppressing the curling of the spacer during cutting, the range of uncoated adhesive material is preferably within the range of 1000 μm from the first edge 24 and the second edge 25, respectively, and more preferably within the range of 200 μm from the first edge 24 and the second edge 25, respectively.

[0170] and then, Figure 7 The bonding surface 80A shown in (c) has the following features: Figure 7 (c) has the same characteristics as the coating area 82A except that the range of the coating area 82A in the vertical direction is different. Figure 7 (b) shows the same shape of the bonding surface.

[0171] Here, Figure 7 The coating areas 82A of the first non-projection portion 82' and the second non-projection portion 82" of the bonding surface 80A shown in (c) are provided at both ends of the bonding surface 80A in the vertical direction. Figure 7 In the first non-projection portion 82' and the second non-projection portion 82" of the bonding surface 80A shown in (c), the portion 82B extending along the first edge 24 and the portion 82B extending along the second edge 25 are not coated with adhesive material, and only the coating area 82A is provided at the upper and lower ends of the first non-projection portion 82' and the second non-projection portion 82".

[0172] If the adhesive is not applied to the portion 82B extending along the first edge 24 and the second edge 25 in this manner, it is possible to prevent the adhesive from adhering to the cutting tool used for cutting and shortening the life of the cutting tool.

[0173] In addition, from the perspective of suppressing the adhesion of the adhesive material to the cutting tool and fully suppressing the curling of the spacer during cutting, the range where the adhesive material is not applied is preferably from the first edge 24 and the second edge 25 to a distance of 1000 μm, and more preferably from the first edge 24 and the second edge 25 to a distance of 200 μm.

[0174] In the above, from the viewpoint of suppressing the adhesion of the adhesive material to the cutting tool and sufficiently suppressing the curling of the spacer during cutting, the shape and range of the coating area are preferably as follows: Figure 7 (b) or Figure 7 (c) The shape and range shown.

[0175] (Secondary Battery)

[0176] The secondary battery of the present invention can be produced using, for example, the method for producing a secondary battery of the present invention, and includes the aforementioned laminate for a secondary battery.

[0177] Specifically, the secondary battery of the present invention has a stacking body obtained by overlapping the secondary battery laminate, additional battery components (electrodes and / or spacers, etc.) provided as needed, an electrolyte, and a battery container for accommodating them. In addition, as the electrolyte, the same electrolyte as the method for manufacturing the secondary battery of the present invention can be used. Moreover, in the secondary battery, in order to prevent the internal pressure of the secondary battery from rising, overcharging and discharging, etc., anti-overcurrent elements such as fuses, PTC elements, metal mesh, guide plates, etc. can also be provided as needed. In addition, the shape of the secondary battery can be any shape such as a coin type, a button type, a sheet type, a cylindrical type, a square type, a flat type, etc.

[0178] Example

[0179] Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not limited to these Examples. In addition, unless otherwise specified, in the following description, "%" and "parts" indicating amounts are based on mass.

[0180] Furthermore, unless otherwise specified, in a polymer produced by copolymerizing a plurality of monomers, the proportion of monomer units formed by polymerizing a certain monomer in the polymer is generally consistent with the ratio (feed ratio) of the certain monomer in all monomers used to polymerize the polymer.

[0181] Moreover, in the embodiments and comparative examples, the shape, average thickness and arrangement spacing of the adhesive material, the unit area mass of the coating area, the dry adhesion of the electrode and the separator, the life of the cutting tool, the curling rate of the separator, and the electrolyte injection properties, output characteristics and cycle characteristics of the secondary battery were measured and evaluated according to the following methods.

[0182] <Adhesive Material Shape, Average Thickness, and Arrangement Spacing>

[0183] The shape of the adhesive material was observed using a laser microscope (manufactured by KEYENCE CORPORATION, VR-3100), and the shape of the adhesive material was observed based on the 2 The average thickness and the number of arrangement spacing of the adhesive materials present in the area are calculated.

[0184] <Weight per unit area of ​​coating area>

[0185] In the range where the adhesive composition was supplied, the difference in weight per unit area before and after supplying the adhesive composition was measured to determine the mass per unit area.

[0186] <Dry Adhesion Strength between Electrode and Separator>

[0187] Under the same conditions as in Examples and Comparative Examples, a negative electrode with an adhesive formed on one side and a separator were bonded together to produce a laminate (i.e., a laminate of one negative electrode and one separator bonded together via an adhesive) as a test piece.

[0188] With the negative electrode current collector side of the test piece facing downward, apply cellophane tape to the negative electrode current collector side. Use cellophane tape as specified in JIS Z1522. The cellophane tape is pre-fixed to a horizontal test bench. Then, stretch one end of the separator vertically upward at a rate of 50 mm / min, and measure the stress during peeling.

[0189] This measurement was performed a total of 6 times, and the average stress value was calculated as the peel strength. The adhesion between the negative electrode and the separator was evaluated according to the following criteria: A greater peel strength indicates a higher adhesion.

[0190] A: Peel strength is 3N / m or more

[0191] B: Peel strength is 1 N / m or more and less than 3 N / m

[0192] C: Peel strength less than 1N / m

[0193] <Cutting tool life>

[0194] The number of cuts immediately after polishing the cutting tool is set to 0. As the number of cuts increases, adhesive material adheres to the blade, stretching the workpiece (bonded body). The number of cuts (shots) at which the percentage of workpieces that cannot be cut within the desired size range of ±1 mm exceeds 1% is calculated as the tool life. A higher number of shots indicates less adhesive adhesion to the blade, and thus a longer tool life.

[0195] A: The number of shots is more than 1 million

[0196] B: The number of shots is more than 500,000 and less than 1 million

[0197] C: The number of shots is less than 500,000

[0198] <Spacer Curl Ratio>

[0199] Disassemble 100 of the prepared stacks (a stack of five secondary battery stacks). For the resulting 500 secondary battery stacks, count the number of separators with edge curling of 2 mm or more. Calculate the separator curling rate (= (number of separators with edge curling / 1000) × 100%) and evaluate according to the following criteria. A lower separator curling rate indicates more suppressed separator curling.

[0200] A: Spacer curling rate is less than 0.1%

[0201] B: The spacer curl rate is 0.1% or more and less than 1%

[0202] C: Spacer curling rate is 1% or more

[0203] <Electrolyte injection properties>

[0204] The prepared overlapping body is wrapped with aluminum packaging material as the outer packaging of the battery, and the electrolyte (solvent: ethylene carbonate / diethyl carbonate / ethylene carbonate = 68.5 / 30 / 1.5 (volume ratio), electrolyte: LiPF6 with a concentration of 1M) is injected while changing the injection time in a way that no air remains.

[0205] The shortest injection time without electrolyte overflow was determined and evaluated according to the following criteria: The shorter the shortest injection time, the better the electrolyte injection performance.

[0206] A: The shortest injection time is less than 100 seconds

[0207] B: The shortest injection time is more than 100 seconds and less than 300 seconds

[0208] C: The shortest injection time is more than 300 seconds and less than 500 seconds

[0209] D: The shortest injection time is more than 500 seconds

[0210] <Output Characteristics>

[0211] The prepared lithium-ion secondary battery is charged to 4.3V by constant current constant voltage (CCCV) at a temperature of 25°C to prepare a battery cell. The prepared battery cell is discharged to 3.0V by a constant current method of 0.2C and 1C at a temperature of -10°C to determine the capacitance. Then, the discharge capacity retention rate expressed as the capacitance ratio (= (capacity at 1C / capacity at 0.2C) × 100 (%)) is determined. These measurements are performed on 5 battery cells of the lithium-ion secondary battery, and the average value of the discharge capacity retention rate is used as the output characteristic, and evaluated according to the following standards. The larger the value, the better the low-temperature output characteristic.

[0212] A: The average discharge capacity retention rate is above 80%

[0213] B: The average discharge capacity retention rate is 70% or more and less than 80%

[0214] C: The average discharge capacity retention rate is 60% or more and less than 70%

[0215] D: The average value of discharge capacity retention rate is less than 60%

[0216] <Cycling Characteristics>

[0217] The produced lithium ion secondary battery was charged to 4.4V by a constant current method of 0.5C at a temperature of 45°C, and then discharged to 3.0V, and the charge and discharge operation was repeated for 200 cycles. Then, the charge and discharge capacity maintenance rate represented by the ratio of the capacitance at the end of 200 cycles to the capacitance at the end of 5 cycles (= (capacity at the end of 200 cycles / capacitance at the end of 5 cycles) × 100 (%)) was calculated. These measurements were performed on 5 battery cells of the lithium ion secondary battery, and the average value of the obtained charge and discharge capacity maintenance rate was used as the cycle characteristics, and evaluated according to the following standards. The larger the value, the better the cycle characteristics.

[0218] A: The average charge and discharge capacity retention rate is above 95%

[0219] B: The average charge and discharge capacity retention rate is 90% or more and less than 95%

[0220] C: The average value of the charge and discharge capacity retention rate is less than 90%

[0221] (Example 1)

[0222] <Preparation of adhesive materials>

[0223] [Preparation of granular polymer having a core-shell structure]

[0224] First, to form the core, 88 parts of styrene as an aromatic vinyl monomer, 6 parts of n-butyl acrylate as a (meth)acrylate monomer, 5 parts of methacrylic acid as an acidic monomer, 1 part of ethylene glycol dimethacrylate as a crosslinking monomer, 1 part of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water, and 0.5 parts of potassium persulfate as a polymerization initiator were added to a 5 MPa pressure-resistant container equipped with a stirrer. After thorough stirring, the mixture was heated to 60°C to initiate polymerization. When the polymerization conversion reached 96%, 80.7 parts of n-butyl acrylate and 1 part of methacrylic acid as (meth)acrylate monomers, 18 parts of styrene as an aromatic vinyl monomer, and 0.3 parts of allyl methacrylate as a crosslinking monomer were added successively to form the shell. The mixture was then heated to 70°C and polymerization continued. The reaction was then terminated by cooling when the polymerization conversion reached 96%, producing an aqueous dispersion containing particulate polymer.

[0225] [Preparation of other bonding materials]

[0226] 70 parts of ion-exchanged water, 0.15 parts of sodium lauryl sulfate (manufactured by Kao Chemicals, product name "EMAL 2F") as an emulsifier, and 0.5 parts of ammonium persulfate were respectively supplied to a reactor equipped with a stirrer, the gas phase was replaced with nitrogen, and the temperature was raised to 60°C.

[0227] Separately, in a separate container, 50 parts of ion-exchanged water, 0.5 parts of sodium dodecylbenzenesulfonate as an emulsifier, and 94 parts of n-butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 1 part of N-methylol acrylamide, and 1 part of allyl glycidyl ether as polymerizable monomers were mixed to obtain a monomer mixture. This monomer mixture was continuously added to the above-mentioned reactor over a period of 4 hours to allow polymerization to proceed. During the addition, the reaction was carried out at 60°C. After the addition was completed, the mixture was further stirred at 70°C for 3 hours to terminate the reaction, thereby producing an aqueous dispersion containing an acrylic polymer (another binder).

[0228] <Preparation of Adhesive Composition>

[0229] In a stirring container, 87 parts of an aqueous dispersion of a particulate polymer and 13 parts of an aqueous dispersion of an acrylic polymer were mixed. To the resulting mixture was added 87 parts of propylene glycol as a polyol compound, and further ion-exchanged water was added to obtain an adhesive composition having a solids concentration of 15%.

[0230] <Production of negative electrode raw materials>

[0231] In a 5 MPa pressure-resistant container equipped with a stirrer, 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid, 63.5 parts of styrene, 0.4 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water, and 0.5 parts of potassium persulfate as a polymerization initiator were added. After thorough stirring, the mixture was heated to 50°C to initiate polymerization. When the polymerization conversion rate reached 96%, the mixture was cooled to terminate the reaction, yielding a mixture containing the binder material (SBR) for the negative electrode composite material layer. A 5% aqueous sodium hydroxide solution was added to the mixture containing the binder material for the negative electrode composite material layer, and after adjusting the pH to 8, unreacted monomers were removed by heating and reduced-pressure distillation. The mixture was then cooled to below 30°C to yield an aqueous dispersion containing the desired binder material for the negative electrode composite material layer.

[0232] Next, 100 parts of artificial graphite (volume average particle size: 15.6 μm) as a negative electrode active material, 1 part of a 2% aqueous solution of carboxymethyl cellulose sodium salt (manufactured by Nippon Paper Industries, Ltd., product name "MAC350HC") as a viscosity modifier, and ion exchange water were mixed, and after adjusting the solid content concentration to 68%, the mixture was further mixed at 25°C for 60 minutes. Furthermore, after adjusting the solid content concentration to 62% with ion exchange water, the mixture was further mixed at 25°C for 15 minutes. To the obtained mixed solution, 1.5 parts of the above-mentioned aqueous dispersion containing the binder for the negative electrode composite material layer and ion exchange water were added, and the final solid content concentration was adjusted to 52%, and the mixture was mixed for another 10 minutes. The mixture was degassed under reduced pressure to obtain a slurry composition for a secondary battery negative electrode with good fluidity.

[0233] The obtained secondary battery negative electrode slurry composition was applied to both sides of a 20 μm thick copper foil as a current collector using a notch wheel coater in a manner such that the film thickness after drying was about 150 μm, and the film was dried. The drying was carried out by conveying the copper foil at a speed of 0.5 m / min for 2 minutes in an oven at 60°C. Then, a heat treatment was performed at 120°C for 2 minutes to obtain a negative electrode raw material before pressing. The negative electrode raw material before pressing was rolled by roller pressing to obtain a negative electrode raw material after pressing with a thickness of 80 μm for the negative electrode composite material layer.

[0234] <Production of positive electrode raw materials>

[0235] 100 parts of LiCoO2 with a volume average particle size of 12 μm as a positive electrode active material, 2 parts of acetylene black (manufactured by Denka Company Limited, product name "HS-100") as a conductive material, 2 parts of polyvinylidene fluoride (manufactured by KUREHA CORPORATION, product name "#7208") as a binder, and N-methylpyrrolidone as a solvent were mixed to a total solids concentration of 70%. These were mixed using a planetary mixer to obtain a slurry composition for a secondary battery positive electrode.

[0236] The resulting secondary battery positive electrode slurry composition was applied to both sides of a 20 μm thick aluminum foil serving as a current collector using a notched wheel coater to a dry film thickness of approximately 150 μm. The resulting film was then dried. The aluminum foil was conveyed in an oven at 60°C at a speed of 0.5 m / min for 2 minutes. The resulting positive electrode material was then heated at 120°C for 2 minutes.

[0237] Then, the obtained positive electrode raw material was rolled using a roll press to obtain a pressed positive electrode raw material having a positive electrode composite material layer.

[0238] <Preparation of spacer materials>

[0239] A spacer raw material made of polypropylene (PP) (product name "Celgard 2500") was prepared.

[0240] <Manufacturing of Laminated Body for Secondary Battery>

[0241] Using the prepared adhesive composition, negative electrode raw material, positive electrode raw material and separator raw material, such as Figure 8 The secondary battery stack is prepared as shown. Figure 8 In the figure, reference numeral 91 denotes a conveying roller, and reference numeral 92 denotes a heating roller.

[0242] Specifically, while the negative electrode material 20A was fed from a negative electrode material roll at a speed of 10 m / min, an adhesive composition was supplied from the inkjet head of an inkjet coater 52 (manufactured by Konica, KM1024 (shear-mode type)) onto one surface of the negative electrode material 20A. Then, the second separator material 30A and the negative electrode material 20A, fed from a separator material roll, were bonded together using press rollers 61 and 62. Furthermore, an adhesive composition was supplied from the inkjet head of an inkjet coater 51 (manufactured by Konica, KM1024 (shear-mode type)) onto the other surface of the negative electrode material 20A. Then, a stack of the first separator material 10A, the negative electrode material 20A, and the second separator material 30A, fed from the separator material roll, was bonded together using press rollers 61 and 62. Furthermore, an adhesive composition is supplied from the inkjet head of an inkjet coating machine 53 (manufactured by KONICA, KM1024 (shear mode type)) to the surface of the first separator raw material 10A opposite to the negative electrode raw material 20A side, and after the previously cut positive electrode 40 is placed, the laminate of the first separator raw material 10A, the negative electrode raw material 20A, and the second separator raw material 30A and the positive electrode 40 are bonded using pressure rollers 61 and 62. Then, an adhesive composition is supplied from the inkjet head of an inkjet coating machine 54 (manufactured by KONICA, KM1024 (shear mode type)) to the top of the positive electrode 40, and then cut using a cutting machine 70 to obtain a secondary battery laminate in which the second separator, the negative electrode, the first separator, and the positive electrode are stacked in this order. The life of the cutting tool was then evaluated. The results are shown in Table 1.

[0243] In addition, in the process of supplying the adhesive composition from each of the coating machines 51 to 54, the coating regions of the coating machines 51 and 52 are Figure 6 The shape and range shown in (b) and the mass per unit area of ​​the adhesive material were as shown in Table 1. The coating machines 53 and 54 were operated so that the adhesive composition was supplied only to the portion where the positive electrode was located (the first coating portion). Furthermore, the bonding using the pressure rollers 61 and 62 was performed at a temperature of 70°C and a pressure of 1 MPa.

[0244] <Manufacturing of stacked bodies>

[0245] Five of the prepared secondary battery stacks were stacked and pressed at a temperature of 70° C. and a pressure of 1 MPa for 10 seconds to obtain a stack.

[0246] The results are shown in Table 1.

[0247] <Manufacturing of Secondary Batteries>

[0248] The stacked structure was wrapped in an aluminum outer packaging material, which served as the outer packaging of the battery. An electrolyte solution (solvent: ethylene carbonate / diethyl carbonate / vinylene carbonate = 68.5 / 30 / 1.5 (volume ratio), electrolyte: LiPF6 at a concentration of 1M) was injected. The opening of the aluminum outer packaging material was then sealed by heat sealing at 150°C to produce a stacked lithium-ion secondary battery with a capacity of 800 mAh.

[0249] The electrolyte injection properties, output characteristics, and cycle characteristics of the secondary batteries were evaluated. The results are shown in Table 1.

[0250] (Example 2)

[0251] Each coating area Figure 6 The adhesive composition is supplied from the coating machines 51 and 52 in the shape and range shown in (a). Except for this, the adhesive material, the adhesive composition, the negative electrode raw material, the positive electrode raw material, the separator raw material, the secondary battery stack, the stack and the secondary battery are produced and prepared in the same manner as in Example 1.

[0252] Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0253] (Example 3)

[0254] Each coating area Figure 5 The adhesive composition is supplied from the coating machines 51 and 52 in the shape and range shown. Except for this, the adhesive material, the adhesive composition, the negative electrode raw material, the positive electrode raw material, the separator raw material, the secondary battery stack, the stack and the secondary battery are produced and prepared in the same manner as in Example 1.

[0255] Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0256] (Example 4)

[0257] The adhesive material, adhesive composition, negative electrode raw material, positive electrode raw material, separator raw material, secondary battery stack, stack and secondary battery are prepared in the same manner as in Example 1 except that the unit area mass and arrangement spacing of the adhesive material in the coating area 82A of the second coating portion 82 are changed as shown in Table 1.

[0258] Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0259] (Example 5)

[0260] The adhesive material, adhesive composition, negative electrode raw material, positive electrode raw material, separator raw material, secondary battery stack, stack and secondary battery are prepared in the same manner as in Example 1, except that the unit area mass and arrangement spacing of the adhesive material in the coating area 81A of the first coating portion 81 and the unit area mass of the adhesive material in the coating area 82A of the second coating portion 82 are changed to those shown in Table 1.

[0261] Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0262] (Example 6)

[0263] The average thickness and arrangement spacing of the adhesive material in the coating area 82A of the second coating portion 82 are changed as shown in Table 1. Except for this, the same procedure as in Example 1 is followed to produce and prepare adhesive materials, adhesive compositions, negative electrode raw materials, positive electrode raw materials, separator raw materials, secondary battery stacks, stacks, and secondary batteries.

[0264] Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0265] (Comparative Example 1)

[0266] As the coating machines 51 to 54, gravure coaters were used instead of inkjet coating machines, and the weight per unit area was 0.02 g / m 2 The adhesive, adhesive composition, negative electrode material, positive electrode material, separator material, secondary battery laminate, stacked body, and secondary battery were prepared in the same manner as in Example 1 except that the adhesive was applied to the entire bonding surface.

[0267] Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0268] [Table 1]

[0269]

[0270] Table 1 shows that curling of the separator was suppressed in Examples 1 to 6. On the other hand, curling of the separator occurred in Comparative Example 1 in which the adhesive material was uniformly applied to the entire bonding surface.

[0271] Industrial applicability

[0272] According to the present invention, a laminate for a secondary battery in which curling of a separator can be suppressed can be obtained.

[0273] Furthermore, according to the present invention, a secondary battery capable of exhibiting excellent battery performance can be obtained using the laminate for a secondary battery in which curling of the separator is suppressed.

[0274] Description of Reference Numerals

[0275] 10: First spacer 10A: First spacer material

[0276] 20: Negative electrode 20A: Negative electrode raw materials

[0277] 21: Negative electrode current collector 22, 23: Negative electrode composite material layer

[0278] 24: First edge 25: Second edge

[0279] 26: Third edge 27: Fourth edge

[0280] 30: Second spacer 30A: Second spacer material

[0281] 40: Positive electrode 41: Current collector for positive electrode

[0282] 42, 43: Positive electrode composite material layer 51-54: Coating machine

[0283] 61, 62: Pressing rollers 70: Cutting machine

[0284] 80: Laminating surface 81: First coating portion

[0285] 81': Projection part 81A: Coating area

[0286] 82: Second coating portion 82': First non-projection portion

[0287] 82″: Second non-projection portion 82A: Coating area

[0288] 82B: Section 83: Cut-off location

[0289] 91: Transport roller 92: Heating roller

[0290] 100, 100A: Secondary battery stack 200: Stack

Claims

1. A laminate for a secondary battery, comprising a negative electrode, a first separator, a positive electrode, and a second separator, The first separator is attached to one side surface of the negative electrode, The positive electrode is attached to the surface of the first separator opposite to the negative electrode side. The second separator is attached to the other surface of the negative electrode or the surface of the positive electrode opposite to the first separator. The size of the positive electrode in a plan view is smaller than the sizes of the negative electrode, the first separator, and the second separator in a plan view. The negative electrode has a first edge and a second edge facing each other in a direction perpendicular to the stacking direction in a plan view, When viewed from the stacking direction, the positive electrode is located between the first edge and the second edge, The separator bonded to the negative electrode and the bonded surface of the negative electrode have a projected portion where the positive electrode is projected when the positive electrode is projected in the stacking direction, and a non-projected portion where the positive electrode is not projected. The non-projection portion includes a first non-projection portion located closer to the first edge than the projection portion, and a second non-projection portion located closer to the second edge than the projection portion. The projection portion, the first non-projection portion, and the second non-projection portion each have a coating area coated with an adhesive material. The unit area mass of the adhesive material in the coating area of ​​the first non-projection part and the second non-projection part is 0.02 g / m greater than the unit area mass of the adhesive material in the coating area of ​​the projection part. 2 Above and 0.50g / m 2 the following, The unit area mass of the coating area of ​​the projection part is 0.01 g / m 2 Above and 3.00g / m 2 the following.

2. The secondary battery laminate according to claim 1, wherein In the non-projection portion, no adhesive material is applied to an edge portion extending along the first edge and an edge portion extending along the second edge.

3. The secondary battery laminate according to claim 1 or 2, wherein In the non-projection portion, no adhesive material is applied in a range of 1000 μm from the first edge and in a range of 1000 μm from the second edge. 4 . A secondary battery comprising the laminate for a secondary battery according to claim 1 .

5. A method for producing a laminate for a secondary battery, The secondary battery stack includes a negative electrode, a first separator, a positive electrode, and a second separator, wherein the first separator is attached to one surface of the negative electrode, the positive electrode is attached to the surface of the first separator opposite to the negative electrode, and the second separator is attached to the other surface of the negative electrode or the surface of the positive electrode opposite to the first separator. The size of the positive electrode in a plan view is smaller than the sizes of the negative electrode, the first separator, and the second separator in a plan view. The method for manufacturing a secondary battery stack includes the following steps: Step A, preparing a laminated body, The laminate comprises a negative electrode material consisting of a long negative electrode raw material or a negative electrode, a long first separator raw material adhered to one side surface of the negative electrode material, and a long second separator raw material adhered to the other side surface of the negative electrode material, or The laminate is formed by laminating a negative electrode material composed of a long negative electrode material, a long first separator material, a positive electrode, and a long second separator material in this order. and step B, cutting the bonded body, The step A includes a step a1 of applying an adhesive material to the bonding surface of the negative electrode material and the separator raw material bonded to the negative electrode material. In the step a1, the adhesive material is applied in a manner that a first coating portion and a second coating portion are alternately positioned in the longitudinal direction of the laminate, the first coating portion having an area coated with the adhesive material at a mass per unit area M1, and the second coating portion having a mass per unit area greater than the mass per unit area M1 by 0.02 g / m 2 Above and 0.50g / m 2 The area where the adhesive material is applied has a mass per unit area M2 of 0.01 g / m 2 Above and 3.00g / m 2 the following, In the step B, the laminate is cut within the range where the second coating portion is located. In the obtained laminate for a secondary battery, the positive electrode is arranged at a position facing the first coating portion.

6. The method for producing a laminate for a secondary battery according to claim 5, wherein: The adhesive material is applied using an inkjet method.

7. The method for producing a laminate for a secondary battery according to claim 5 or 6, wherein: The bonded body is not coated with an adhesive material in a portion extending along the cut position cut in the step B.

8. The method for producing a laminate for a secondary battery according to claim 5 or 6, wherein: The bonded body was not coated with an adhesive material in a range extending from the cutting position in the step B to 1000 μm on both sides in the longitudinal direction.

9. A method for manufacturing a secondary battery, comprising the following steps: A step of manufacturing a plurality of secondary battery stacks using the method for manufacturing a secondary battery stack according to any one of claims 5 to 8, a step of stacking the obtained secondary battery stacks to obtain a stacked body, and A step of housing the stacked body in a battery container.

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