Stacked body, electrode structure, battery, and flying object

Abstract

A laminate having a plurality of sheet materials stacked is provided. In the laminate, each of the plurality of sheet materials has a support layer including a thermoplastic resin material, and a first metal layer and a second metal layer formed on both surfaces of the support layer. In a part of the plurality of sheet materials, a plurality of the first metal layers and a plurality of the second metal layers included in the plurality of sheet materials are integrated, and each of the plurality of the first metal layers and the plurality of the second metal layers includes a concave-convex region in which each metal layer has a corrugated shape or a shape in which wrinkles are gathered.

Description

TECHNICAL FIELD

[0001] The present application relates to a laminate, an electrode structure, a battery, and a flying object. BACKGROUND

[0002] Patent Documents 1 and 2 disclose a welding method of a material containing a resin and a metal. Patent Document 3 discloses a current collector provided with a conductive material in a through-hole.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2004-130331

[0006] Patent Document 2: Japanese Patent Application Publication No. 2006-305591

[0007] Patent Document 3: Japanese Patent Application Publication No. 2019-186204 SUMMARY

[0008] In a first aspect of the present application, a laminate is provided. The above-described laminate, for example, has a plurality of sheet materials laminated. In the above-described laminate, each of the plurality of sheet materials, for example, has a support layer containing a thermoplastic resin material. Each of the plurality of sheet materials, for example, has a first metal layer and a second metal layer formed on both faces of the support layer. According to the above-described laminate, for example, in a part of the plurality of sheet materials, a plurality of first metal layers and a plurality of second metal layers contained in the plurality of sheet materials are integrated. In the above-described laminate, each of the plurality of first metal layers and the plurality of second metal layers, for example, contains a concave-convex region in which each metal layer has a corrugated shape or a shape in which wrinkles are gathered.

[0009] It can also be that the above-described laminate does not have the plurality of first metal layers and the plurality of second metal layers integrated in the concave-convex region. In the above-described laminate, it can also be that each metal layer contains a plurality of peak portions and at least one valley portion arranged and provided along an in-plane direction of each metal layer. In the above-described laminate, it can also be that the concave-convex region is provided adjacent to an integrated region in which the plurality of first metal layers and the plurality of second metal layers are integrated.

[0010] In any of the above-described laminates, it can also be that the proportion of the volume of the resin contained in the region in which the plurality of first metal layers and the plurality of second metal layers are integrated, that is, the integrated region, with respect to the volume of the metal contained in the integrated region is 5 to 50%. In the above-described laminate, it can also be that the proportion of the volume of the void contained in the region in which the plurality of first metal layers and the plurality of second metal layers are integrated, that is, the integrated region, with respect to the volume of the metal contained in the integrated region is 10% or less.

[0011] In any of the above laminates, the plurality of sheet materials can include a first sheet material disposed at an outermost side of one side of the plurality of sheet materials, and a second sheet material disposed at an outermost side of the other side of the plurality of sheet materials. The above laminate can further include a first support member supporting the first sheet material, and a second support member supporting the second sheet material. In the above laminate, the first support member and the second support member can include a metal. In a portion of the plurality of sheet materials, the first support member, the second support member, the plurality of first metal layers, and the plurality of second metal layers can be integrated.

[0012] In any of the above laminates, each of the plurality of sheet materials can have a region in which a plurality of through-holes are formed in each sheet material, in the vicinity of a region in which the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., an integrated region. The above laminate can further include a conductive member electrically connecting the first metal layer and the second metal layer disposed in each of the plurality of sheet materials.

[0013] Any of the above laminates can have an integrated region in which the plurality of first metal layers and the plurality of second metal layers are integrated by welding.

[0014] Any of the above laminates can have a smooth region in which a difference between a maximum value and a minimum value of measured values of thickness at three points in the interior is less than or equal to 5% of an average value of the measured values of thickness at the three points.

[0015] In any of the above laminates, the concave-convex region can be formed in an adjacent region disposed between the integrated region and the smooth region.

[0016] In any of the above laminates, a maximum value of thickness of the adjacent region can be greater than the average value of the measured values of thickness at the three points in the smooth region. In any of the above laminates, the maximum value of thickness of the adjacent region can be 1.0 to 1.5 times the average value of the measured values of thickness at the three points in the smooth region. In any of the above laminates, the maximum value of thickness of the adjacent region can be 1.1 to 1.3 times the average value of the measured values of thickness at the three points in the smooth region.

[0017] In any of the above laminated bodies, the plurality of sheet materials can each have a region with a plurality of through-holes formed therein in the vicinity of the integrated region. The proportion of the volume of the resin contained in the integrated region to the volume of the metal contained in the integrated region can be 5 to 50%. The proportion of the volume of the resin contained in the integrated region to the volume of the metal contained in the integrated region can be 5 to 30%. The proportion of the volume of the resin contained in the integrated region to the volume of the metal contained in the integrated region can be 5 to 20%.

[0018] In any of the above laminated bodies, the shape of the concave-convex region in a plane substantially perpendicular to the stacking direction of the plurality of sheet materials is a substantially concentric circle or a substantially concentric polygonal shape.

[0019] In any of the above laminated bodies, the number of peaks provided in the concave-convex region can be two or more. In any of the above laminated bodies, the number of peaks provided in the concave-convex region can be three or more. In any of the above laminated bodies, the number of peaks provided in the concave-convex region can be six or more. In any of the above laminated bodies, the number of peaks provided in the concave-convex region can be ten or more.

[0020] In a second aspect of the application, an electrode structure is provided. The electrode structure includes, for example, a first electrode and a second electrode. The electrode structure includes, for example, a third electrode. The electrode structure includes, for example, a first separator and a second separator. In the electrode structure, for example, the first electrode, the first separator, the third electrode, the second separator, and the second electrode are stacked in this order. In the electrode structure, each of the first electrode and the second electrode includes, for example, a current collector and an active material layer provided on at least one face of the current collector. In the electrode structure, the current collector includes, for example, a support layer including a thermoplastic resin material and first and second metal layers formed on both faces of the support layer. According to the electrode structure, for example, the first and second metal layers of the first electrode and the first and second metal layers of the second electrode are integrated in the vicinity of the end portions of the first and second electrodes. In the electrode structure, each of the first and second metal layers of the first electrode and the first and second metal layers of the second electrode includes, for example, a concave-convex region in which each metal layer has a corrugated shape or a shape in which wrinkles are gathered.

[0021] The electrode structure can further include a fourth electrode and a third separator. In the electrode structure, the first electrode, the first separator, the third electrode, the second separator, the second electrode, the third separator, and the fourth electrode can be sequentially stacked. In the electrode structure, the first electrode, the second electrode, the third electrode, and the fourth electrode can each include a current collector and an active material layer. In the vicinity of the end portion of the third electrode and the fourth electrode, the first metal layer and the second metal layer of the third electrode and the first metal layer and the second metal layer of the fourth electrode can be integrated. The first metal layer and the second metal layer of the third electrode and the first metal layer and the second metal layer of the fourth electrode can each include a concave-convex region in which each metal layer has a corrugated shape or a shape in which wrinkles are gathered.

[0022] In a third aspect of the application, a battery is provided. The battery includes any of the electrode structures of the second aspect. The battery can include a housing that houses the electrode structure.

[0023] In a fourth aspect of the application, a flying object is provided. The flying object includes any of the batteries of the third aspect. The flying object can include a propulsion force generating device that generates a propulsion force using electric power stored in the battery.

[0024] The summary of the application is not intended to list all features required by the application. In addition, sub-combinations of these feature groups can also be applications. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 An example of a system configuration of a flying object 100 is schematically shown.

[0026] Figure 2 An example of a battery cell 112 is schematically shown.

[0027] Figure 3 Another example of a battery cell 112 is schematically shown.

[0028] Figure 4 An example of a current collector 400 is schematically shown.

[0029] Figure 5 An example of a current collector 500 is schematically shown.

[0030] Figure 6 An example of a current collector 600 is schematically shown.

[0031] Figure 7 An example of a stacked structure 760 is schematically shown.

[0032] Figure 8An example of the electrode connection relationship of the stacked structure 760 is schematically shown.

[0033] Figure 9 An example of the manufacturing method of the battery core 112 is schematically shown.

[0034] Figure 10 An example of the manufacturing method of the positive electrode 220 is schematically shown.

[0035] Figure 11 An example of the welding process using the welding device 1120 is shown.

[0036] Figure 12 An example of the plurality of through holes 620 provided in the current collector 1102 is shown.

[0037] Figure 13 An example of the plurality of through holes 620 provided in the current collector 1102 is shown.

[0038] Figure 14 An example of the process of manufacturing the stacked structure 760 is shown.

[0039] Figure 15 An example of the plan view of the positive electrode connection portion 820 is schematically shown.

[0040] Figure 16 An example of the cross section of the positive electrode connection portion 820 is schematically shown.

[0041] Figure 17 An example of the cross section of the positive electrode connection portion 820 is schematically shown.

[0042] Figure 18 An example of the positive electrode current collector 222 including the concave-convex region 1600 is schematically shown.

[0043] Figure 19 An example of the concave-convex region 1900 is schematically shown.

[0044] Figure 20 Another example of the cross section of the positive electrode connection portion 820 is schematically shown.

[0045] Figure 21 Still another example of the cross section of the positive electrode connection portion 820 is schematically shown.

[0046] Figure 22 An example of the observation result of the X-ray CT of the welding portion and its periphery of Example 1 is shown.

[0047] Figure 23 An example of the observation result of the X-ray CT of the observation region 2200 is shown.

[0048] Figure 24An example of an observation result of X-ray CT that shows the observation region 2300 is shown.

[0049] Figure 25 An example of an SEM image of a cross section of a welded portion and its periphery of Comparative Example 1 is shown. DETAILED DESCRIPTION

[0050] According to an embodiment exemplified in the present specification (sometimes referred to as the present embodiment.), a laminate is produced by welding a part of a plurality of welding objects that are laminated. The plurality of welding objects each have: a support layer including a resin material; and a first metal layer and a second metal layer formed on both faces of the support layer. The welding object can be a sheet-shaped material (sometimes referred to as a sheet material.). The welding object can be a current collector for an electrode of a battery.

[0051] The first metal layer and the second metal layer of each of the plurality of welding objects are electrically connected. Thereby, the first metal layer and the second metal layer can be welded, for example, by resistance welding.

[0052] The kind of the resin material is not particularly limited, but as the resin material, any thermoplastic resin material can be used. The support layer can be substantially composed of a thermoplastic resin material, and the support layer can be a thermoplastic resin material.

[0053] The use of a thermoplastic resin material as a main component of the support layer thereby improves, for example, the safety of a battery in a case where the laminate is used as an electrode of the battery. More specifically, in a case where the above-described battery is in thermal runaway, the thermoplastic resin material is fused by the heat. As a result thereof, the thermal runaway can be suppressed.

[0054] Further, a thermoplastic resin material softens and the flowability thereof increases as the temperature of the resin material rises. Thereby, in a welding process of the plurality of welding objects, if pressure is applied to the welding objects that are heated, the resin material disposed between the first metal layer and the second metal layer easily moves, and the first metal layer and the second metal layer approach or contact each other. In this state, the first metal layer and the second metal layer are integrated by applying energy to the first metal layer and the second metal layer.

[0055] According to an example of the present embodiment, the plurality of welding objects are welded by the following process. First, energy is applied to a softened region that is disposed in a part of the plurality of welding objects. As described above, the support layer of the welding object of the present embodiment contains, for example, a thermoplastic resin material as a main component. If appropriate energy is applied to the softened region of the welding object, the temperature of the thermoplastic resin material contained in the support layer rises, and the resin material softens.

[0056] Next, the welding region provided to at least a part of the softened region of the welding object is pressed. Thereby, the resin material provided to the support layer between the first metal layer and the second metal layer is pressed. The resin material present inside the welding region is softened and has moderate fluidity. Therefore, if the resin material of the support layer is pressed with a proper size of pressure, the resin material moves inside the welding object.

[0057] In the case where the first metal layer and the second metal layer are welded, if the first metal layer and the second metal layer are pressed to be close to or contact with each other, the resin material provided between the first metal layer and the second metal layer is pressed out to the periphery of the welding site. The inventors of the present application have found that, depending on the thickness of the first metal layer and the second metal layer, the volume of the resin material pressed out to the periphery of the welding site, the viscosity or the ease of movement of the resin material, and the like, sometimes the first metal layer and the second metal layer provided to the periphery of the welding site are broken by the resin material when the resin material provided to the welding site is pressed out to the periphery of the welding site.

[0058] Further, the inventors of the present application have found that, in the case where the above-mentioned breakage of the metal layer occurs, the measured value of the resistance between the plurality of sheet materials integrated deviates more than a predetermined threshold value. For example, consider the case where a part of a sheet material A, a sheet material B, and a sheet material C are integrated by welding. As described above, each sheet material includes a support layer including a resin material, and a first metal layer and a second metal layer formed on both surfaces of the support layer. The sheet material A, the sheet material B, and the sheet material C are laminated so that the second metal layer of the sheet material A contacts the first metal layer of the sheet material B, and the second metal layer of the sheet material B contacts the first metal layer of the sheet material C. Further, a part of the laminated sheet materials are welded by the above-mentioned process.

[0059] In this case, the first metal layer and the second metal layer contained in the sheet material A, the sheet material B, and the sheet material C are integrated at the welding site, and all the metal layers are electrically connected. Therefore, it is considered that the deviation of the resistance between the plurality of metal layers is sufficiently small.

[0060] However, the inventors of the present application found that the measured value of the resistance between an arbitrary point on the first metal layer of the sheet material A and an arbitrary point on the second metal layer of the sheet material A or an arbitrary point on the first metal layer of the sheet material B, the resistance between an arbitrary point on the first metal layer of the sheet material A and an arbitrary point on the second metal layer of the sheet material B or an arbitrary point on the first metal layer of the sheet material C, the resistance between an arbitrary point on the first metal layer of the sheet material A and an arbitrary point on the second metal layer of the sheet material C, the resistance between an arbitrary point on the first metal layer of the sheet material B and an arbitrary point on the second metal layer of the sheet material B or an arbitrary point on the first metal layer of the sheet material C, the resistance between an arbitrary point on the first metal layer of the sheet material B and an arbitrary point on the second metal layer of the sheet material C, and the resistance between an arbitrary point on the first metal layer of the sheet material C and an arbitrary point on the second metal layer of the sheet material C sometimes deviated. The reason for this is not completely clear, but it is presumed that the conductive path around the welded portion becomes complicated as a result of the fracture of at least a part of the first metal layer and the second metal layer provided around the welded portion.

[0061] In addition, the inventors of the present application found that the above deviation is small when the first metal layer and the second metal layer have a corrugated shape or a shape in which wrinkles are gathered (sometimes referred to as a concave-convex region) formed around the welded portion, as compared to when more than half of the first metal layer and the second metal layer contained in the laminate around the welded portion are fractured. The reason why the above deviation is small when the first metal layer and the second metal layer have a concave-convex region formed therearound is not completely clear, but it is presumed that the fracture of the first metal layer and the second metal layer is suppressed by the movement or deformation of the first metal layer and the second metal layer when the resin material provided around the welded portion is pressed out to the vicinity of the welded portion.

[0062] By obtaining the laminate in which the above deviation is small, the deviation of the electrode reaction in each layer of the above laminate-type battery is also suppressed, for example, when the plurality of metal layers constituting the above laminate are used as a part of the current collector constituting the above laminate-type battery. As a result of this, the life characteristics of the laminate-type battery are improved.

[0063] Further, the inventors of the present application found that, for example, in a case where the above-mentioned support layer contains a thermoplastic resin having a lower melting point than that of the polyimide as a main component, the above-mentioned concave-convex region can be formed. As the main component of the support layer, a component having a content of more than 50% by mass in the support layer, a component having a content of 51% by mass or more in the support layer, and the like are exemplified. Further, the inventors of the present application found that, in a case where one or more through-holes penetrating the support layer, the first metal layer, and the second metal layer are formed at and / or in the vicinity of the welding site of the welding object before welding, the above-mentioned concave-convex region can be formed.

[0064] As described above, the above-mentioned welding object is, for example, a current collector for an electrode of a battery, and the method of producing the above-mentioned laminate or the method of welding a plurality of laminated welding objects can be applied to the production of an electrode structure provided inside a case of a battery (particularly, a secondary battery). Further, according to the present embodiment, a part of the current collector is formed by a substance (typically, air or a resin material) having a smaller density than that of an aluminum foil or a copper foil.

[0065] As a result, a battery core having an excellent energy density per unit mass and / or capacity of an active material per unit mass can be provided. For example, according to the present embodiment, a battery core having an energy density per unit mass of 350 [Wh / kg - battery core] or more can be provided. Further, a battery provided with the battery core according to the present embodiment is particularly suitable for use in a flying object because of the large energy density per unit mass.

[0066] As described above, according to the present embodiment, a rechargeable battery, for example, which can improve the amount of energy per unit weight, which is lighter and can store more electric power, can be realized. The rechargeable battery can be taken to a disaster site, for example, and can be used for energy supply to disaster victims and the like. Therefore, the laminate, the electrode structure, and the battery according to the present embodiment and the methods of producing the same can contribute to the achievement of the goal 7 "Sustainable Energy for All" or the goal 13 "Tangible Measures against Climate Change" of the Sustainable Development Goals (SDGs) and the like.

[0067] Hereinafter, the present application will be described through embodiments of the application, but the following embodiments are not intended to limit the application covered by the claims. Further, the combination of features described in the embodiments is not necessarily all required for the solution of the application.

[0068] In the present specification, in the case where a numerical range is expressed as "A to B", the expression means A or more and B or less. In addition, "substituted or unsubstituted" means "substituted with an arbitrary substituent or not substituted with a substituent". The kind of the above-mentioned substituent is not particularly limited unless mentioned in the specification. In addition, the number of the above-mentioned substituent is not particularly limited unless mentioned in the specification.

[0069] (Summary of the flying object 100)

[0070] Figure 1 An example of the system configuration of the flying object 100 is schematically shown. In the present embodiment, the flying object 100 is provided with a storage battery 110, a power control circuit 120, one or a plurality of electric motors 130, one or a plurality of propellers 140, one or a plurality of sensors 150, and a control device 160. In the present embodiment, the storage battery 110 has one or a plurality of storage battery cores 112.

[0071] In the present embodiment, the flying object 100 flies using electric energy accumulated in the storage battery 110. As the flying object 100, an airplane, an airship or a balloon, a hot air balloon, a helicopter, a drone, or the like can be exemplified.

[0072] In the present embodiment, the storage battery 110 receives electric energy from an external charging device (not shown) via the power control circuit 120, and accumulates the electric energy in one or a plurality of the storage battery cores 112. In addition, the storage battery 110 supplies the electric energy accumulated in one or a plurality of the storage battery cores 112 to the electric motor 130 via the power control circuit 120.

[0073] In the present embodiment, the storage battery core 112 accumulates electric energy (sometimes referred to as charging of the storage battery core 112). In addition, the storage battery core 112 releases the accumulated electric energy (sometimes referred to as discharging of the storage battery core 112). The storage battery core 112 can also be a secondary battery.

[0074] The storage battery core 112 can also be an all-solid battery. The storage battery core 112 can also be an all-solid secondary battery. The all-solid secondary battery is a secondary battery which substantially does not contain the above-mentioned electrolytic solution or gel electrolyte, and for example, is provided with a pair of electrodes and a solid electrolyte layer disposed between the pair of electrodes.

[0075] The fact that the secondary battery substantially does not contain the electrolytic solution or the gel electrolyte means not only a case where the secondary battery does not contain the electrolytic solution or the gel electrolyte, but also a case where the secondary battery contains a small amount of the electrolytic solution or the gel electrolyte. This is because, even in a case where a constituent material of the secondary battery is dissolved in a solvent contained in the electrolytic solution or the gel electrolyte, if the amount of the solvent contained in the secondary battery is small, the influence of the dissolution of the constituent material of the secondary battery in the solvent on the performance of the battery can be ignored.

[0076] In one embodiment, the battery core 112 does not include at least one of (i) an electrolytic solution containing a supporting electrolytic salt and a solvent and (ii) a gel electrolyte containing a supporting electrolytic salt, an organic high-molecular compound, and an organic solvent. In other embodiments, the ratio of the mass [kg] of the electrolytic solution and the gel electrolyte to the mass [kg] of the organic compound used as the active material is less than 5%.

[0077] As the carrier ion of the secondary battery, lithium, sodium, potassium, magnesium, calcium, and the like are exemplified. As the secondary battery, a sodium-ion secondary battery, a lithium-ion secondary battery, a lithium metal secondary battery, a lithium-air secondary battery, a lithium-sulfur secondary battery, a magnesium-ion secondary battery, and the like are exemplified.

[0078] For example, as the active material for the secondary battery mounted on a vehicle, a material capable of storing a large amount of electric charge per unit volume is often selected. On the other hand, in the present embodiment, the battery core 112 is mounted on the flying object 100. Therefore, the active material for the battery core 112 is preferably a material capable of storing a large amount of electric charge per unit mass.

[0079] The mass energy density of the battery core 112 is preferably 350 [Wh / kg-battery core] or more, more preferably 400 [Wh / kg-battery core] or more, more preferably 500 [Wh / kg-battery core] or more, more preferably 600 [Wh / kg-battery core] or more, and further preferably 700 [Wh / kg-battery core] or more. Thereby, a battery core particularly suitable for the use as a power source of a flying object is obtained.

[0080] The volume energy density of the battery core 112 can also be 300 [Wh / m 3 -battery core] or more and 1200 [Wh / m 3 -battery core] or less, 400 [Wh / m 3 -battery core] or more and 1000 [Wh / m 3 -battery core] or less. In the case where the battery core 112 is mounted on the flying object 100 as a part of the power source of the flying object 100, the volume energy density of the battery core 112 can also be 600 [Wh / m 3 -battery core] or less, 800 [Wh / m 3 -battery core] or less.

[0081] The battery core 112 can have a mass energy density within the above numerical range and a volume energy density within the above numerical range. Thereby, a battery core difficult to be used as a power source of a vehicle can be utilized as a power source of a flying object. Details of the battery core 112 will be described later.

[0082] In the present embodiment, the electric power control circuit 120 controls input and output of electric power of the battery 110. The electric power control circuit 120 can also control input and output of electric power of the battery 110 based on a command from the control device 160. The electric power control circuit 120 includes, for example, a plurality of switching elements that act based on a control signal from the control device 160.

[0083] In the present embodiment, the electric motor 130 receives electric power from the battery 110 via the electric power control circuit 120. The electric motor 130 rotates the propeller 140 using the electric power received from the battery 110. Thereby, the electric motor 130 can generate a propulsive force of the flying object 100 using the electric power accumulated in the battery cell 112.

[0084] In the present embodiment, the sensor 150 measures various physical quantities related to the position and posture of the flying object 100. As the sensor for measuring various physical quantities related to the position and posture of the flying object 100, a GPS signal receiver, an acceleration sensor, an angular acceleration sensor, a gyro sensor, and the like are exemplified. The sensor 150 can also measure various physical quantities related to the state of the battery 110. As the sensor for measuring various physical quantities related to the state of the battery 110, a temperature sensor, a current sensor, a voltage sensor, and the like are exemplified.

[0085] In the present embodiment, the control device 160 controls the flying object 100. The control device 160 can also control input and output of electric power of the battery 110 by controlling the electric power control circuit 120. For example, the control device 160 controls an output current, an output voltage, an input current, an input voltage, and the like of the battery 110. Thereby, the control device 160 can control the position and posture of the flying object 100. The control device 160 can also control the position and posture of the flying object 100 based on an output from the sensor 150 by controlling the electric power control circuit 120.

[0086] The battery 110 is an example of a secondary battery. The battery cell 112 can also be an example of a secondary battery. The electric motor 130 can also be an example of a propulsive force generating device. The secondary battery can also be an example of a battery.

[0087] (Outline of the battery cell 112)

[0088] Figure 2 An example of the battery cell 112 is schematically shown. In the present embodiment, details of the battery cell 112 are described taking the case where the battery cell 112 is a coin-type all-solid secondary battery as an example. However, it should be noted that the battery cell 112 is not limited to a coin-type all-solid secondary battery.

[0089] (Battery cell)

[0090] In the present embodiment, the battery cell 112 includes a positive electrode case 212, a negative electrode case 214, a sealant 216, and a metal spring 218. In addition, the battery cell 112 includes a positive electrode 220, a separator 230, and a negative electrode 240. In the present embodiment, the positive electrode 220 includes a positive electrode current collector 222 and a positive electrode active material layer 224. In the present embodiment, the negative electrode 240 includes a negative electrode current collector 242 and a negative electrode active material layer 244.

[0091] In the present embodiment, the battery cell 112 includes a structure 260 including the positive electrode 220, the separator 230, and the negative electrode 240. As shown in FIG. 2, the positive electrode 220, the separator 230, and the negative electrode 240 are sequentially stacked, and the separator 230 is disposed between the positive electrode 220 and the negative electrode 240. Figure 2

[0092] In the present embodiment, details of the battery cell 112 are described, taking the case where the battery cell 112 does not substantially include an electrolytic solution or a gel electrolyte as an example. In addition, in the present embodiment, details of the battery cell 112 are described, taking the case where the positive electrode current collector 222 includes (i) a conductive layer including a conductive material and (ii) a support layer supporting the conductive layer as an example.

[0093] In the present embodiment, the positive electrode case 212 and the negative electrode case 214 are assembled, and a space is formed inside the positive electrode case 212 and the negative electrode case 214. The metal spring 218, the positive electrode 220, the separator 230, and the negative electrode 240 are housed inside the space formed by the positive electrode case 212 and the negative electrode case 214. The positive electrode 220, the separator 230, and the negative electrode 240 are fixed inside the positive electrode case 212 and the negative electrode case 214 by repulsive force of the metal spring 218.

[0094] The positive electrode case 212 and the negative electrode case 214 are formed of, for example, a conductive material having a thin plate shape like a disc. In the present embodiment, the sealant 216 seals a gap formed between the positive electrode case 212 and the negative electrode case 214. The sealant 216 includes an insulating material. The sealant 216 insulates the positive electrode case 212 and the negative electrode case 214.

[0095] (Positive electrode)

[0096] ​In this embodiment, the positive electrode current collector 222 holds the positive electrode active material layer 224. In this embodiment, the positive electrode current collector 222 has an electric resistance of 0.01 mΩ to 1 Ω. Thus, for example, a variation in voltage measured by applying a current to a conductive layer (details of the conductive layer will be described later) of the positive electrode current collector 222 before and after applying pressure to the conductive layer in the manufacture of the positive electrode current collector 222 is suppressed to less than 100 mV under specific measurement conditions. The positive electrode current collector 222 can have an electric resistance of 0.01 mΩ to 333 mΩ, or an electric resistance of 0.01 mΩ to 100 mΩ.

[0097] The density of the positive electrode current collector 222 is adjusted to 1.1 to 2.0 g / cm 3 Thus, for example, in the case where the main component of the active material contained in the positive electrode active material layer 224 is anthracene (density: 1.3 g / cm 3 ), anthracene (density: 1.25 g / cm 3 ), and / or naphthalene (density: 1.14 g / cm 3 ), the mass of the positive electrode 220 having the positive electrode current collector 222 and the positive electrode active material layer 224 is very light, and the mass energy density of the battery core 112 is increased.

[0098] In this embodiment, at least a part of the positive electrode current collector 222 is formed of a material having a smaller density than metal. At least a part of the positive electrode current collector 222 can be formed of a material having a smaller density than aluminum. For example, at least a part of the positive electrode current collector 222 is formed of a resin. Thus, the battery core 112 can be made light.

[0099] In particular, in the case where the separator 230 using a solid electrolyte as a main component is used, the mass of the separator 230 becomes relatively large depending on the kind of the solid electrolyte. Even in such a case, since at least a part of the positive electrode current collector 222 is formed of a resin, the increase in the mass of the entire battery core 112 is suppressed. As a result, the capacity per unit mass of the battery core 112 and the energy density of the battery core 112 are increased.

[0100] For example, the positive electrode current collector 222 includes a conductive layer containing a conductive material, and a support layer supporting the conductive layer. Details of the conductive layer and the support layer will be described later.

[0101] As the shape of the positive electrode current collector 222, a foil shape (sometimes referred to as a plate shape, a film shape, a sheet shape, or the like), a mesh shape, a porous plate shape, or the like is exemplified. The mesh shape and the porous plate shape can also be examples of the foil shape. The thickness of the positive electrode current collector 222 is not particularly limited, but is preferably 1 to 200 μm. The thickness of the positive electrode current collector 222 can be 6 to 20 μm, or 4 to 10 μm.

[0102] In this embodiment, the positive electrode active material layer 224 is formed on at least one surface of the positive electrode current collector 222. The thickness of the positive electrode active material layer 224 can be 1 to 100 μm, or 5 to 50 μm for each single surface of the positive electrode current collector 222.

[0103] The positive electrode active material layer 224 contains, for example, a positive electrode active material and a binder material. The positive electrode active material layer 224 can also contain at least one of an electrically conductive material and an ionically conductive material. The positive electrode active material layer 224 can also contain a positive electrode active material and an ionically conductive material. Thereby, the ionically conductive path and / or the electronically conductive path formed inside the positive electrode active material layer 224 can be inhibited from being cut off.

[0104] In one embodiment, the positive electrode active material layer 224 is formed by applying a slurry containing materials that constitute the positive electrode active material layer 224 and a solvent on at least one surface of the positive electrode current collector 222 and drying the slurry. As the solvent, various solvent materials or mixtures thereof are exemplified. The kind of the solvent material is not particularly limited, but as the solvent material, N-methylpyrrolidone (NMP), water, or the like is exemplified.

[0105] In another embodiment, the positive electrode active material layer 224 is formed by mixing materials that constitute the positive electrode active material layer 224 and molding the mixture in a sheet shape and pressure-bonding the sheet-shaped mixture to at least one surface of the positive electrode current collector 222. In the case where an organic compound is used as the positive electrode active material, the positive electrode current collector 222 and the positive electrode active material layer 224 can be pressure-bonded in a manner that excessive pressure is not applied to the positive electrode active material layer 224 in the above-described pressure-bonding process.

[0106] For example, when a coating machine is used to coat the precursor material of the positive electrode active material layer 224 on the positive electrode current collector 222, the pressure applied to the precursor material of the positive electrode active material layer 224 is adjusted. For example, the coating gap of the coating machine is set to 180 μm or more. The coating gap can also be set to 200 μm or more. Thereby, the ionically conductive path and / or the electronically conductive path in the positive electrode active material layer 224 can be inhibited from being cut off.

[0107] (Positive electrode active material)

[0108] As the positive electrode active material contained in the positive electrode active material layer 224, for example, various materials capable of occluding and releasing the carrier ions of the battery core 112 are used. The positive electrode active material can be an inorganic compound or an organic compound. The above-described positive electrode active material can be used alone or two or more kinds of positive electrode active materials can be combined.

[0109] As described above, the positive electrode 220 has the positive electrode current collector 222 and the positive electrode active material layer 224. The mass of the positive electrode active material layer 224 can also be 80% or more of the total mass of the positive electrode 220. The mass of the positive electrode active material can also be 80% or more of the total mass of the positive electrode active material layer 224.

[0110] As an inorganic compound used as the positive electrode active material (sometimes referred to as an inorganic positive electrode active material), a metal oxide, a metal silicate, a metal phosphate, a metal borate, or the like is exemplified. As the metal, a transition metal such as V, Mn, Ni, Co, or the like is exemplified.

[0111] As an organic compound used as the positive electrode active material (sometimes referred to as an organic positive electrode active material), various compounds having redox activity are used as the organic positive electrode active material. As the organic positive electrode active material, a conjugated polymer, a disulfide, a quinone, a localized radical, a non-localized radical, or the like is exemplified.

[0112] The organic positive electrode active material can also be an organic compound having a relatively small molecular weight and having a multiple electron donating and accepting ability. In the case where the above-described organic compound is a low molecular compound, the molecular weight of the organic compound is, for example, 500 or less. In the case where the above-described organic compound is a polymer or an oligomer, the molecular weight of the organic compound is, for example, 5000 or less.

[0113] (Materials other than the positive electrode active material)

[0114] The binding material contained in the positive electrode active material layer 224 binds the materials that constitute the positive electrode active material layer 224, and maintains the electrode shape of the positive electrode 220. As the binding material, various polymer materials are used, for example. As the above-described polymer material, carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylic acid, polyethylene oxide (PEO), poly(3,4-ethylenedioxythiophene) (PEDOT), and derivatives thereof, or the like is exemplified.

[0115] In the case where the organic positive electrode active material is used as the positive electrode active material, the binding material can also be a material that dissolves in a solvent having a solubility greater than a predetermined value with respect to the organic positive electrode active material. The solubility of the binding material in the above-described solvent can also be greater than or equal to the solubility of the organic positive electrode active material in the above-described solvent. Thereby, for example, in the case where the constituent materials of the battery core 112 are reused, the decomposition process of the battery core 112 becomes easy.

[0116] The conductive material contained in the positive electrode active material layer 224 increases the conductivity of the positive electrode active material layer 224. Thus, the resistance of the positive electrode 220 decreases. The conductive material is not particularly limited as long as it is a material having electron conductivity. As the conductive material, a carbon-based material, a metal-based material, a conductive polymer material, or the like is exemplified. These conductive materials can be used alone or in combination of two or more.

[0117] As the carbon-based material, graphite, carbon black (for example, acetylene black, ketjen black, or the like), coke, amorphous carbon, carbon fiber, carbon nanotube, graphene, or the like is exemplified. As the metal-based material, aluminum, gold, silver, copper, iron, platinum, chromium, tin, indium, titanium, nickel, or the like is exemplified. As the conductive polymer material, a polyphenylene derivative, or the like is exemplified.

[0118] In a case where the organic positive electrode active material is used as the positive electrode active material, the conductive material can be a material that is dissolved in a solvent having a solubility greater than a predetermined value with respect to the organic positive electrode active material. The solubility of the conductive material in the above-described solvent can be greater than or equal to the solubility of the organic positive electrode active material in the above-described solvent. Thus, for example, in a case where the constituent material of the battery core 112 is reused, the decomposition process of the battery core 112 becomes easy.

[0119] The conductive material contained in the positive electrode active material layer 224 increases the conductivity of the carrier ions in the positive electrode active material layer 224. As the conductive material, various solid electrolytes are used, for example. As the solid electrolyte, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer solid electrolyte, or the like is exemplified. As the conductive material, a polymer solid electrolyte can also be used. As the polymer solid electrolyte, at least one compound selected from the group consisting of polyethylene oxide (PEO), poly(3,4-ethylenedioxythiophene) (PEDOT), and derivatives thereof is exemplified.

[0120] As described later, in the present embodiment, the separator 230 contains a polymer solid electrolyte. The kind of the polymer solid electrolyte used as the conductive material can be the same as or different from the kind of the polymer solid electrolyte contained in the separator 230.

[0121] In a case where the organic positive electrode active material is used as the positive electrode active material, the conductive material can be a material that is dissolved in a solvent having a solubility greater than a predetermined value with respect to the organic positive electrode active material. The solubility of the conductive material in the above-described solvent can be greater than or equal to the solubility of the organic positive electrode active material in the above-described solvent. Thus, for example, in a case where the constituent material of the battery core 112 is reused, the decomposition process of the battery core 112 becomes easy.

[0122] (Seperator)

[0123] In the present embodiment, the separator 230 is provided between the positive electrode 220 and the negative electrode 240 to separate the positive electrode 220 and the negative electrode 240. Further, the separator 230 ensures the ion conductivity between the positive electrode 220 and the negative electrode 240. The thickness of the separator 230 is not particularly limited, but is preferably 10 to 50 μm.

[0124] In the present embodiment, the separator 230 has a layered (sometimes referred to as a plate-shaped, sheet-shaped, flake-shaped, or the like) solid electrolyte (sometimes referred to as a solid electrolyte layer). Thereby, the solid electrolyte layer functions as a separator of the battery cell 112.

[0125] In one embodiment, as the separator 230, a solid electrolyte layer is used. The solid electrolyte layer can be composed of a single solid electrolyte layer, or can be composed of a plurality of solid electrolyte layers. In other embodiments, as the separator 230, a laminate of one or more solid electrolyte layers and another layer containing a material other than a solid electrolyte is used. The other layer can also have ion conductivity. As the other layer, a composite material having a resin in which a plurality of through-holes are formed and an ion-conductive material filled inside the through-holes is exemplified.

[0126] Thereby, a secondary battery not containing an electrolytic solution or a gel electrolyte can be produced. As a result thereof, even in a case where the positive electrode active material layer 224 and / or the negative electrode active material layer 244 contains an organic active material as a main active material, reduction in the battery life due to dissolution of the organic active material in a solvent of an electrolytic solution or a gel electrolyte can be suppressed.

[0127] In addition, the separator 230 is not limited to the above-described embodiments. For example, a porous material in which a solid electrolyte is provided inside the pores is used as the separator 230. It can also be that the separator 230 is produced by impregnating a suitable support material or a holding material with a gel electrolyte or an electrolytic solution, and impregnating the gel electrolyte or the electrolytic solution inside the support material or the holding material, and then solidifying the electrolyte provided inside the support material or the holding material. For example, the electrolyte provided inside the support material or the holding material is solidified by drying the support material or the holding material containing the gel electrolyte or the electrolytic solution.

[0128] As the solvent of the electrolytic solution or the gel electrolyte, ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), butylene carbonate (BC), fluoroethylene carbonate (FEC), γ-butyrolactone, sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, and a mixture thereof are exemplified. In particular, ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethylmethyl carbonate (EMC) are widely used as the solvent of the electrolytic solution or the gel electrolyte.

[0129] (Solid electrolyte layer)

[0130] In the present embodiment, the separator 230 has a solid electrolyte layer containing a high-molecular solid electrolyte as a main constituent material. The solid electrolyte layer contains, for example, 80% by mass or more of a true high-molecular solid electrolyte. In the case where the separator 230 contains a high-molecular solid electrolyte as a main constituent material, the separator 230 can be joined to the positive electrode 220 and / or the negative electrode 240 without a pressing process under high pressure.

[0131] The solid electrolyte layer is produced by, for example, applying a slurry containing a material constituting the solid electrolyte layer and a solvent on a smooth support plate and drying the slurry. As the solvent, various solvents or a mixture thereof are exemplified. The kind of the solvent is not particularly limited, but N-methylpyrrolidone (NMP), water, methanol, or the like is exemplified as the solvent.

[0132] As the high-molecular solid electrolyte constituting the solid electrolyte layer, at least one compound selected from the group consisting of polyethylene oxide (PEO), poly(3,4-ethylenedioxythiophene) (PEDOT), and a derivative thereof is exemplified. The solid electrolyte layer can be substantially composed of a single high-molecular solid electrolyte, or can contain two or more high-molecular solid electrolytes.

[0133] (Negative electrode)

[0134] In the present embodiment, the negative electrode current collector 242 holds the negative electrode active material layer 244. As the material of the negative electrode current collector 242, copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof, or the like is exemplified.

[0135] The negative electrode current collector 242 can contain a conductive resin. The negative electrode current collector 242 can be a conductive resin. In one embodiment, the conductive resin contains a conductive polymer. In another embodiment, the conductive resin can be a polymer containing a conductive filler.

[0136] The negative current collector 242 can also have the same configuration as the positive current collector 222. For example, the negative current collector 242 includes a conductive layer including a conductive material and a support layer supporting the conductive layer. The support layer is formed of a material having a smaller density than metal. The support layer can also be formed of a material having a smaller density than aluminum. For example, the support layer is formed of a resin. Thus, the battery cell 112 can be made lightweight.

[0137] In a case where a carrier metal is used as the negative active material, the carrier metal can function as a current collector. For example, in a case where the carrier metal of the battery cell 112 is lithium and the negative active material is lithium metal, the lithium metal is used as a current collector. In this case, the battery cell 112 can not include the negative current collector 242.

[0138] As the shape of the negative current collector 242, a foil shape (sometimes referred to as a plate shape, a film shape, or the like), a mesh shape, a porous plate shape, or the like is exemplified. The mesh shape and the porous plate shape can also be examples of the foil shape. The thickness of the negative current collector 242 is not particularly limited, but can be 1 to 200 μm. The thickness of the negative current collector 242 can also be 4 to 20 μm, or 6 to 10 μm.

[0139] In the present embodiment, the negative active material layer 244 is formed on at least one surface of the negative current collector 242. The thickness of the negative active material layer 244 can also be 0 to 200 μm, or 1 to 100 μm per each single surface of the negative current collector 242.

[0140] The negative active material layer 244 includes, for example, a negative active material and a binder material (sometimes referred to as a binding agent). The negative active material layer 244 can further include at least one of a conductive material and an ion-conductive material. The negative active material layer 244 can include a negative active material and an ion-conductive material. Thus, the ion-conductive path and / or the electron-conductive path formed inside the negative active material layer 244 can be inhibited from being cut off.

[0141] In one embodiment, the negative active material layer 244 is produced by applying a slurry including a material constituting the negative active material layer 244 and an organic solvent on at least one surface of the negative current collector 242 and drying the slurry. As the solvent, various solvent materials or mixtures thereof are exemplified. The kind of the solvent material is not particularly limited, but as the solvent material, N-methylpyrrolidone (NMP), water, or the like is exemplified.

[0142] In other embodiments, the negative electrode active material layer 244 is formed by mixing materials that constitute the negative electrode active material layer 244 and molding the mixture in a sheet shape, and pressure-bonding the sheet-shaped mixture to at least one face of the negative electrode current collector 242. Also, in a case where an organic compound is used as the negative electrode active material, the negative electrode current collector 242 and the negative electrode active material layer 244 are pressure-bonded in a manner that does not apply excessive pressure to the negative electrode active material layer 244 in the above-described pressure-bonding process.

[0143] For example, when a coating machine is used to coat the precursor material of the negative electrode active material layer 244 on the negative electrode current collector 242, the pressure applied to the precursor material of the negative electrode active material layer 244 is adjusted. For example, the coating gap of the coating machine is set to 180 μm or more. The above-described coating gap can also be set to 200 μm or more. Thereby, the ion conduction path and / or the electron conduction path in the negative electrode active material layer 244 are suppressed from being cut off.

[0144] (Negative electrode active material)

[0145] As the negative electrode active material contained in the negative electrode active material layer 244, for example, various substances capable of occluding and releasing the carrier ions of the battery core 112 are used. The negative electrode active material can be an inorganic compound or an organic compound. These negative electrode active materials can be used alone or two or more kinds of negative electrode active materials can be combined. For example, a metal foil capable of releasing the carrier ions of the battery core 112 is used as the negative electrode active material layer 244. Thereby, the mass energy density of the battery core 112 is increased.

[0146] In one embodiment, the negative electrode current collector 242 is provided with a conductive layer containing a conductive material and a support layer that supports the conductive layer, similarly to the positive electrode current collector 222. In this case, the mass of the negative electrode active material layer 244 can also be 80% or more of the total mass of the negative electrode 240. The mass of the negative electrode active material can also be 80% or more of the total mass of the negative electrode active material layer 244. In other embodiments, a metal (for example, Li metal) capable of releasing the carrier ions of the battery core 112 is used as the negative electrode active material. In this case, almost the entire negative electrode active material contained in the negative electrode active material layer 244 is constituted by the metal. Further, in a case where the negative electrode active material layer 244 is a foil-shaped metal as described above, the negative electrode 240 can also not be provided with the negative electrode current collector 242.

[0147] As the inorganic compound used as the negative electrode active material (sometimes referred to as an inorganic negative electrode active material), (i) a carrier metal and an alloy containing the same, (ii) tin, silicon, and an alloy containing the same, (iii) silicon oxide, (iv) titanium oxide, and the like are exemplified. For example, in the case where the battery cell 112 is a lithium secondary battery, as the negative electrode active material, metallic lithium, lithium-titanium oxide (LTO), or the like is used. In the case where a material not containing a carrier metal is used as the negative electrode active material, the material can also be pre-doped with a carrier metal.

[0148] As the organic compound used as the negative electrode active material (sometimes referred to as an organic negative electrode active material), various compounds having redox activity are used as the organic positive electrode active material. As the organic positive electrode active material, a conjugated polymer, a disulfide, a quinone, a localized radical, a non-localized radical, and the like are exemplified.

[0149] The organic positive electrode active material can also be an organic compound having a relatively small molecular weight and having a multi-electron donating and accepting ability. In the case where the above-described organic compound is a low molecular compound, the molecular weight of the organic compound is, for example, 500 or less. In the case where the above-described organic compound is a polymer or an oligomer, the molecular weight of the organic compound is, for example, 5000 or less.

[0150] As described above, the negative electrode active material layer 244 can also contain a carrier metal in the form of a foil. For example, the negative electrode active material layer 244 contains a lithium metal foil. Thereby, the battery cell 112 is supplied with a carrier metal. The thickness of the metal foil can also be 1 to 200 μm, can also be 10 to 100 μm, and can also be 20 to 50 μm. The thickness and / or the mass of the metal foil can also be determined in accordance with the content of the positive electrode active material in the positive electrode active material layer 224.

[0151] (Materials other than the negative electrode active material)

[0152] The binder material contained in the negative electrode active material layer 244 binds the materials constituting the negative electrode active material layer 244, and maintains the electrode shape of the negative electrode 240. As the binder material, various polymer materials are used, for example. As the above-described polymer material, carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylic acid, polyethylene oxide (PEO), poly(3,4-ethylenedioxythiophene) (PEDOT), and derivatives thereof, and the like are exemplified.

[0153] In the case where the organic negative electrode active material is used as the negative electrode active material, the binder material can also be a material that is dissolved in a solvent having a solubility greater than a predetermined value with respect to the organic negative electrode active material. The solubility of the binder material in the above-described solvent can also be greater than or equal to the solubility of the organic negative electrode active material in the above-described solvent. Thus, for example, in the case where the constituent material of the battery core 112 is reused, the decomposition process of the battery core 112 becomes easier.

[0154] The electrically conductive material contained in the negative electrode active material layer 244 increases the electrical conductivity of the negative electrode active material layer 244. Thus, the resistance of the negative electrode 240 becomes small. The electrically conductive material is not particularly limited as long as it is a material having electron conductivity. As the electrically conductive material, a carbon-based material, a metal-based material, an electrically conductive polymer material, or the like is exemplified. These electrically conductive materials can be used alone or in combination of two or more.

[0155] As the carbon-based material, graphite, carbon black (for example, acetylene black, ketjen black, or the like), coke, amorphous carbon, carbon fiber, carbon nanotube, graphene, or the like is exemplified. As the metal-based material, aluminum, gold, silver, copper, iron, platinum, chromium, tin, indium, titanium, nickel, or the like is exemplified. As the electrically conductive polymer material, a polyphenylene derivative, or the like is exemplified.

[0156] In the case where the organic negative electrode active material is used as the negative electrode active material, the electrically conductive material can also be a material that is dissolved in a solvent having a solubility greater than a predetermined value with respect to the organic negative electrode active material. The solubility of the binder material in the above-described solvent can also be greater than or equal to the solubility of the organic negative electrode active material in the above-described solvent. Thus, for example, in the case where the constituent material of the battery core 112 is reused, the decomposition process of the battery core 112 becomes easier.

[0157] The conductive material contained in the negative electrode active material layer 244 increases the conductivity of the carrier ions in the negative electrode active material layer 244. As the conductive material, various solid electrolytes are used, for example. As the solid electrolyte, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer solid electrolyte, or the like is exemplified. As the conductive material, a polymer solid electrolyte can also be used. As the polymer solid electrolyte, at least one compound selected from the group consisting of polyethylene oxide (PEO), poly(3,4-ethylenedioxythiophene) (PEDOT), and derivatives thereof is exemplified.

[0158] As described above, in the present embodiment, the separator 230 contains a polymer solid electrolyte. The kind of the polymer solid electrolyte used as the conductive material can be the same as or different from the kind of the polymer solid electrolyte contained in the separator 230.

[0159] In the case where the organic negative electrode active material is used as the negative electrode active material, the conductive material can also be a material that is dissolved in a solvent having a solubility greater than a predetermined value with respect to the organic negative electrode active material. The solubility of the conductive material in the above-described solvent can also be greater than or equal to the solubility of the organic negative electrode active material in the above-described solvent. Thus, for example, in the case where the constituent material of the battery cell 112 is reused, the decomposition process of the battery cell 112 becomes easier.

[0160] The positive electrode case 212 can be an example of a case. The negative electrode case 214 can be an example of a case. The positive electrode 220 can be an example of an electrode. The positive electrode current collector 222 can be an example of a current collector. The positive electrode active material layer 224 can be an example of an active material layer. The negative electrode 240 can be an example of an electrode. The negative electrode current collector 242 can be an example of a current collector. The negative electrode active material layer 244 can be an example of an active material layer. The organic active material can be an example of an organic compound. The organic positive electrode active material can be an example of an organic compound. The organic negative electrode active material can be an example of an organic compound.

[0161] (Example of Other Embodiment)

[0162] In the present embodiment, details of the battery cell 112 are described taking the case where the battery cell 112 is a coin-type secondary battery as an example. However, the kind, structure, and the like of the battery cell 112 are not limited to the present embodiment. In other embodiments, the battery cell 112 can also be a cylindrical battery having a jelly-roll electrode body in which a positive electrode, a separator, and a negative electrode are wound in a spiral shape. In yet other embodiments, the battery cell 112 can also be a laminate-type battery in which a laminate electrode body in which a positive electrode and a negative electrode are alternately stacked with a separator interposed therebetween is sealed by lamination. In still other embodiments, the structure body 260 can have a plurality of positive electrodes 220 stacked, and the positive electrode current collectors 222 of the respective positive electrodes 220 can be integrated in some of the stacked positive electrodes 220. The structure body 260 can also have a plurality of negative electrodes 240 stacked, and the negative electrode current collectors 242 of the respective negative electrodes 240 can be integrated in some of the stacked negative electrodes 240. In this case, the structure body 260 can also be an example of a laminate or an electrode structure.

[0163] In the present embodiment, details of the battery cell 112 are described taking the case where the negative electrode 240 has the negative electrode current collector 242 and the negative electrode active material layer 244 as an example. However, the negative electrode of the battery cell 112 is not limited to the present embodiment. In other embodiments, a foil-shaped carrier metal functions as the negative electrode current collector 242 and the negative electrode active material layer 244. For example, in the case where the battery cell 112 is a lithium metal secondary battery, metallic lithium can be used as the negative electrode.

[0164] Figure 3 Another example of the battery cell 112 is schematically shown. Differences Figure 3 The battery cell 112 described above differs in that the electrolyte 350 is a liquid or gel, and in that the separator 230 can be made of a material other than a solid electrolyte. Figure 2 The battery cell 112 described above differs in that the electrolyte 350 is a liquid or gel, and in that the separator 230 can be made of a material other than a solid electrolyte. Figure 3 The battery cell 112 described above differs in that the electrolyte 350 is a liquid or gel, and in that the separator 230 can be made of a material other than a solid electrolyte. Figure 2 The battery cell 112 described above differs in that the electrolyte 350 is a liquid or gel, and in that the separator 230 can be made of a material other than a solid electrolyte.

[0165] As the electrolyte 350, a known electrolytic solution or gel electrolyte can be used. As the separator 230, a known separator can be used.

[0166] The details of the positive electrode current collector 222 are described using Figure 4 , Figure 5 and Figure 6 The details of the positive electrode current collector 222 are described using Figure 4 A cross-sectional view of a current collector 400 that is an example of the positive electrode current collector 222 is schematically shown. Figure 5 A cross-sectional view of a current collector 500 that is an example of the positive electrode current collector 222 is schematically shown. Figure 6 A cross-sectional view of a current collector 600 that is an example of the positive electrode current collector 222 is schematically shown.

[0167] As shown in FIG. 4, the current collector 400 includes a support layer 420, a conductive layer 442, and a conductive layer 444. In the present embodiment, the support layer 420 has a first plane 422, a second plane 424, and a side surface 426. In the present embodiment, the conductive layer 442 is disposed on the first plane 422 of the support layer 420. The conductive layer 444 is disposed on the second plane 424 of the support layer 420. Figure 4 In the present embodiment, the support layer 420 supports the conductive layer 442 and the conductive layer 444. Thereby, the breakage of the conductive layer 442 and the conductive layer 444 is suppressed. The density of the support layer 420 is lower than the density of the conductive layer 442 or the conductive layer 444. For example, the support layer 420 is made of a material having a density lower than the density of the conductive layer 442 or the conductive layer 444. The support layer 420 can also be a sheet-shaped resin material.

[0168]

[0169] ​The resin material can be a thermoplastic resin or a thermosetting resin. The support layer 420 can be composed of a single kind of resin material or can include a plurality of kinds of resin materials. As described above, in the case where a part of the plurality of current collectors 400 that are laminated is welded, the resin material preferably mainly includes a thermoplastic resin or is substantially composed of a thermoplastic resin. Thereby, for example, by heating the support layer before welding, the flowability of the support layer is improved. Further, in the case where the support layer 420 mainly includes a thermoplastic resin or the case where the support layer 420 is substantially composed of a thermoplastic resin, compared with the case where the support layer 420 mainly includes a thermosetting resin or the case where the support layer 420 is substantially composed of a thermosetting resin, the plurality of current collectors 400 are firmly welded. Thereby, a laminate in which the strength of the welded portion position is excellent and the resistance of the welded portion position is small can be produced.

[0170] The thermoplastic resin can also be a resin having at least one property selected from the group consisting of (i) a property that the thermal conductivity at 20°C is 0.6 W / mK or less, (ii) a property that the specific heat at 20°C is 2500 J / kg°C or less, (iii) a property that the thermal shrinkage at 20°C is 1% or less, (iv) a property that the melting point is 300°C or less, and (v) a property that the density at 20°C is 1.9 g / cm 3 The thermoplastic resin can also be a resin having at least one property selected from the group consisting of (i) a property that the thermal conductivity at 20°C is 0.6 W / mK or less, (ii) a property that the specific heat at 20°C is 2500 J / kg°C or less, (iii) a property that the thermal shrinkage at 20°C is 1% or less, (iv) a property that the melting point is 300°C or less, and (v) a property that the density at 20°C is 1.9 g / cm

[0171] As the thermoplastic resin, polyethylene (PE), polyethylene terephthalate (PET), polyacrylonitrile (PAN), polypropylene (PP), polyphenylene sulfide (PPS), or the like is exemplified. As the polyethylene, high-density polyethylene, low-density polyethylene, or the like is exemplified. As the polypropylene, biaxially stretched polypropylene (OPP), non-stretched polypropylene (CCP), or the like is exemplified.

[0172] The support layer 420 can also be substantially composed of one or more kinds of resin materials selected from the group consisting of PET, PP, and PE. Thereby, compared with the case where the support layer 420 is substantially composed of polyimide (sometimes referred to as PI), in welding a part of the plurality of current collectors 400 that are laminated, it is easy to form the above-described concave-convex region in the conductive layer 442 and the conductive layer 444. As a result thereof, the breakage of the conductive layer 442 and / or the conductive layer 444 at the time of welding is suppressed.

[0173] The electric conductivity of the support layer 420 is not particularly limited, but the electric conductivity of the support layer 420 can also be lower than that of the conductive layer 442 or the conductive layer 444. The thickness of the support layer 420 is not particularly limited, but the thickness of the support layer 420 can also be greater than that of the conductive layer 442 or the conductive layer 444. If the thickness of the support layer 420 is increased, the mass of the support layer 420 is also increased. Therefore, in the case where the support layer 420 is a sheet-shaped resin material, the thickness of the resin material can also be 10 μm or less, preferably 7 μm or less, and further preferably 5 μm or less.

[0174] The thickness of the above-described resin material is preferably 1 μm or more and 10 μm or less at 20°C. The thickness of the above-described resin material can also be 1 μm or more and 7 μm or less at 20°C, and can also be 1 μm or more and 5 μm or less at 20°C.

[0175] In the present embodiment, the conductive layer 442 and the conductive layer 444 contain an electrically conductive material. The electrically conductive material can also be a material having an electric resistivity of 8.0 x 10 -8 [Ω·m] or more. The electrically conductive material can also be a metal. As the above-described metal, aluminum, stainless steel, nickel, or alloys thereof, or the like is exemplified. As the stainless steel, SUS-430, SUS-304, or the like is exemplified. The electrically conductive material can also be aluminum.

[0176] The thickness of the conductive layer 442 and / or the conductive layer 444 (in the drawing, shown as the length in the up-and-down direction.) can also be 0.05 μm to 7 μm. The thickness of the conductive layer 442 and / or the conductive layer 444 can also be 0.05 μm to 5 μm, 0.1 μm to 3 μm, 0.1 μm to 2 μm, or 0.5 μm to 1 μm. The thickness of the conductive layer 442 and / or the conductive layer 444 can also be 0.05 μm to 4 μm, 0.05 μm to 3 μm, 0.05 μm to 2 μm, or 0.05 μm to 1 μm. The thickness of the conductive layer 442 and / or the conductive layer 444 is preferably 0.1 μm to 5 μm, and further preferably 0.1 μm to 1 μm. Even if the commercially available aluminum foil is a relatively thin aluminum foil, it has a thickness of 6 to 10 μm, and therefore, by providing the current collector 400 with the conductive layer 442 and / or the conductive layer 444 having a thickness of 5 μm or less, the energy density per unit mass of the battery core [Wh / kg-battery core] is increased compared to the case where a commercially available aluminum foil is used as the conductive layer 442 and / or the conductive layer 444.

[0177] At least one of the conductive layer 442 and / or the conductive layer 444 can also be a layered or foiled aluminum having the above-described thickness. The layered or foiled aluminum can also be provided on the surface of the support layer 420 by adhesion, or can be formed on the surface of the support layer 420 by a vapor deposition method, a build-up method, or the like.

[0178] In a case where the thickness of the conductive layer 442 and / or the conductive layer 444 is 7 μm or less, the mass energy density of the battery cell 112 is increased. In a case where the thickness of the conductive layer 442 and / or the conductive layer 444 is 5 μm or less, the mass energy density of the battery cell 112 is further increased. In a case where the thickness of the conductive layer 442 and / or the conductive layer 444 is 1 μm or less, the mass energy density of the battery cell 112 is greatly increased. In general, if the thickness of the conductive layer is 0.1 μm or less or less than 0.1 μm, the thickness of the conductive layer 442 and / or the conductive layer 444 is easily broken. However, the conductive layer 442 and the conductive layer 444 according to the present embodiment are supported by the support layer 420. Therefore, even in a case where the thickness of the conductive layer 442 and / or the conductive layer 444 is about 0.05 to 0.1 μm, the breakage of the conductive layer 442 and / or the conductive layer 444 can be suppressed.

[0179] As shown in FIG. 5, the current collector 500 is different from the current collector 400 described in relation to the fact that a plurality of through holes 522 are formed in the support layer 420. Figure 5 The current collector 500 can have the same configuration as the current collector 400 except for the above-described difference. Figure 4 In a case where a simple metal foil is used as the current collector, if a through hole is to be formed in the current collector, the metal foil is bent, and it is sometimes difficult to form the through hole. Therefore, in particular, in a case where active material layers are formed on both surfaces of the metal foil, it is difficult to form a through hole in the current collector. In contrast to this, according to the present embodiment, the conductive layer is supported by the support layer such as a resin sheet, and therefore, even if a through hole is formed in the current collector, the current collector is less likely to be bent.

[0180] According to the present embodiment, a conductive material 546 is filled in a part of the plurality of through holes 522. The conductive material 546 electrically connects the conductive layer 442 and the conductive layer 444.

[0181] The equivalent circle diameter (sometimes referred to as the equivalent circle diameter) of each of the plurality of through holes 522 can be 15 μm to 150 μm. The interval between two adjacent through holes 522 can be 30 μm to 250 μm.

[0182] The equivalent circle diameter (sometimes referred to as the equivalent circle diameter) of each of the plurality of through holes 522 can be 15 μm to 150 μm. The interval between two adjacent through holes 522 can be 30 μm to 250 μm.

[0183] If the equivalent diameter of the through-hole 522 is smaller than 15 μm, forming an internal conductive layer (sometimes called an inner conductive layer) with sufficient thickness may become difficult, or the time and effort required to form such a layer may increase, when a conductive layer (sometimes called an inner conductive layer) for electrically connecting the conductive layers 442 and 444 is formed on the inner wall surface of the through-hole 522. If the thickness of the inner conductive layer is insufficient, its resistance may increase. On the other hand, if the equivalent diameter of the through-hole 522 is larger than 150 μm, the area of ​​the support layer 420 supporting the conductive layers 442 and 444 becomes smaller. As a result, the total amount of conductive layers 442 and 444 contained in the current collector 500 becomes smaller, and the resistance of the conductive layers 442 and 444 may increase. Furthermore, if the equivalent diameter of the through-hole 522 is larger than 150 μm, the strength of the current collector 500 may be insufficient.

[0184] The equivalent circular diameter (sometimes called equivalent circle diameter) of each of the multiple through holes 522 can be 15μm to 150μm, 15μm to 50μm, or 15 to 35μm. The equivalent circular diameter of the through holes 522 that are not filled with conductive material 546 can also be 15μm to 50μm or 15 to 35μm. The equivalent circular diameter of the through holes 522 that are filled with conductive material 546 is not particularly limited. As a result, the breakage of conductive layer 442 and conductive layer 444 can be suppressed, and the current collector 500 can be made lighter.

[0185] The sum of the areas of the plurality of through holes 522 in one side of the current collector 500 can also be 30% or more of the area of ​​the outer surface of one side of the current collector 500. The sum of the areas of the through holes 522 in one side of the current collector 500 that are not filled with conductive material 546 can also be 30% or more of the area of ​​the outer surface of one side of the current collector 500. Therefore, breakage of the conductive layer 442 and the conductive layer 444 can be suppressed, and the current collector 500 can be made lighter.

[0186] like Figure 6 As shown, the current collector 600 is related to the fact that it has a plurality of through holes 620 that penetrate the support layer 420, the conductive layer 442, and the conductive layer 444. Figure 5 The current collector 500 described is different. Aside from the differences mentioned above, the current collector 500 can have the same configuration as the current collector 500. For example, the through-hole 620 has the same structure as the through-hole 522, except that it penetrates the conductive layer 442 and the conductive layer 444.

[0187] In this embodiment, the electrically conductive layer 642 is formed on the surface of the inner wall portion 622 of at least a part of the plurality of through holes 620. The electrically conductive layer 642 can also electrically connect the electrically conductive layer 442 and the electrically conductive layer 444.

[0188] In this embodiment, the electrically conductive layer 642 contains an electrically conductive material. The electrically conductive material can also be a metal. As the metal, aluminum, stainless steel, nickel, or an alloy thereof, or the like is exemplified. As the stainless steel, SUS-430, SUS-304, or the like is exemplified. The electrically conductive material can also be aluminum.

[0189] The electrically conductive layer 642 can also have a plurality of layers having different main components. The electrically conductive layer 642 can also have three or more layers having different main components. The electrically conductive layer 642, for example, has an auxiliary layer, a target layer, and a protective layer. For example, a first layer having nickel as a main component is formed on the surface of the inner wall portion 622 of the through hole 620, a second layer having copper as a main component is formed on the first layer, and a chromium plating film is formed on the second layer. The thickness of the first layer can be about 0.1 μm, the thickness of the second layer can be about 1 μm, and the thickness of the chromium plating film can be about 0.3 μm.

[0190] The current collector 400 can be an example of the sheet material. The current collector 400 can be an example of the first sheet material or the second sheet material. The support layer 420 can be an example of the support layer. The electrically conductive layer 442 can be an example of one of the first metal layer and the second metal layer. The electrically conductive layer 444 can be an example of the other of the first metal layer and the second metal layer.

[0191] The current collector 500 can be an example of the sheet material. The current collector 500 can be an example of the first sheet material or the second sheet material. The electrically conductive material 546 can also be an example of the electrically conductive member.

[0192] The current collector 600 can be an example of the sheet material. The current collector 600 can be an example of the first sheet material or the second sheet material. The inner wall portion 622 can be an example of the inner wall of the through hole. The electrically conductive layer 642 can be an example of the electrically conductive member.

[0193] (Example of Other Embodiment)

[0194] In this embodiment, details of the current collector 400, the current collector 500, and the current collector 600 are described, taking the case where the support layer 420 contains or is substantially composed of a thermoplastic resin in a case where a part of the plurality of current collectors are welded. However, the current collector 400, the current collector 500, and the current collector 600 are not limited to this embodiment.

[0195] In other embodiments, the support layer 420 can also mainly contain a thermosetting resin or can substantially consist of a thermosetting resin, in a case where the conductive layers 442 and 444 provided on both sides of the support layer 420 are electrically connected. In particular, according to the current collector 500, the inside of at least a portion of the plurality of through holes 522 is filled with the conductive material 546. Similarly, according to the current collector 600, the inside of at least a portion of the plurality of through holes 620 is formed with the conductive layer 642. Thus, even if the conductive layers 442 and 444 of a single current collector do not come close to or contact each other, a portion of the plurality of current collectors that are laminated can be integrated by welding. In addition, the support layer is heated before welding, and thus the flowability of the support layer is reduced. Thus, the support layer is inhibited from being pressed out around the welding site, and as a result, the volume expansion around the welding site is inhibited.

[0196] In the present embodiment, the support layer 420 is associated with Figure 4 and details of the current collector 400 are described, taking a case where no through hole is formed in the support layer 420 as an example. In addition, the support layer 420 is associated with Figure 5 and Figure 6 and details of the current collector 500 and the current collector 600 are described, taking a case where the equivalent circle diameter of the through hole 522 or the through hole 620 is 15 μm to 150 μm as an example. However, the current collector 400, the current collector 500, and the current collector 600 are not limited to the present embodiment.

[0197] In other embodiments, the current collector 400, the current collector 500, and / or the current collector 600 can be formed with a through hole having an equivalent circle diameter of 30 μm to 5 mm and passing through the current collector. The through hole having an equivalent circle diameter of 30 μm to 5 mm is provided, for example, at or near the center of gravity of the welding site (sometimes referred to as the approximate center). Thus, the volume of the resin material pressed out from the welding site is reduced. As a result, the breakage of the conductive layers 442 and 444 is further inhibited. The inner wall of the above-mentioned through hole can be formed with a conductive layer that electrically connects the conductive layers 442 and 444. Thus, the welding of the plurality of sheet materials can be facilitated.

[0198] In other embodiments of the current collector 500, the through hole having an equivalent circle diameter of 30 μm to 5 mm can be formed instead of or together with the through hole 522. The equivalent circle diameter of the above-mentioned through hole can be larger than the equivalent circle diameter of the through hole 522. In other embodiments of the current collector 600, the through hole having an equivalent circle diameter of 30 μm to 5 mm can be formed instead of or together with the through hole 620. The equivalent circle diameter of the above-mentioned through hole can be larger than the equivalent circle diameter of the through hole 620.

[0199] In this embodiment, the details of the current collector 500 and current collector 600 are described using the example of conductive layer 442 and conductive layer 444 being electrically connected by conductive material 546 or conductive layer 642 disposed inside the through hole formed in the support layer 420. However, the current collector 400, current collector 500, and current collector 600 are not limited to this embodiment. In other embodiments, the conductive layer 442 and conductive layer 444 may be electrically connected by conductive members disposed on at least a portion of the side surface of the support layer 420.

[0200] use Figure 7 as well as Figure 8 Details of the stacked structure 760, another example of an electrode structure, are explained below. Figure 7 An example of a cross-section of the stacked structure 760 is shown schematically. Figure 8 An example of the electrical connection relationship of the electrodes of the stacked structure 760 is shown schematically.

[0201] In association Figure 2 In the described embodiment, the case where a positive electrode 220, a separator 230, and a negative electrode 240 are sequentially stacked in structure 260 is used as an example to illustrate the details of a structure (sometimes called an electrode structure) that constitutes part of a battery. However, the electrode structure is not limited to structure 260. The stacked structure 760 differs from structure 260 in that it has multiple positive electrodes 220, multiple separators 230, and multiple negative electrodes 240. Apart from the differences mentioned above, the stacked structure 760 may have the same configuration as structure 260.

[0202] like Figure 7 As shown, in this embodiment, the laminated structure 760 includes: one or more positive electrodes 220, one or more negative electrodes 240, and one or more separators 230 disposed between each of the one or more positive electrodes 220 and each of the one or more negative electrodes 240. Figure 7 As shown, the stacked structure 760 includes a plurality of positive electrodes 220, a plurality of negative electrodes 240, and a plurality of diaphragms 230 disposed between each of the plurality of positive electrodes 220 and each of the plurality of negative electrodes 240.

[0203] Apart from the outermost positive electrode 220 disposed on the laminated structure 760, each of the plurality of positive electrodes 220 has a positive electrode active material layer 224 disposed on both sides of the positive electrode current collector 222. The outermost positive electrode 220 disposed on the laminated structure 760 has a positive electrode active material layer 224 disposed on one side of the positive electrode current collector 222.

[0204] The plurality of negative electrodes 240 each have a negative electrode active material layer 244 disposed on both faces of the negative electrode current collector 242, except for the negative electrode 240 disposed at the outermost side of the stacked structure 760. The negative electrode 240 disposed at the outermost side of the stacked structure 760 has a negative electrode active material layer 244 disposed on one face of the negative electrode current collector 242.

[0205] In the present embodiment, the positive electrode active material layer 224 is disposed on a portion of the positive electrode current collector 222. For example, in the vicinity of at least one end portion of the positive electrode current collector 222, the positive electrode active material layer 224 is not formed on at least one face of the positive electrode current collector 222. The plurality of positive electrodes 220 are stacked, for example, in such a manner that the end portions of the side on which the positive electrode active material layer 224 is not formed are directed in substantially the same direction.

[0206] In the present embodiment, the negative electrode active material layer 244 is disposed on a portion of the negative electrode current collector 242. For example, in the vicinity of at least one end portion of the negative electrode current collector 242, the negative electrode active material layer 244 is not formed on at least one face of the negative electrode current collector 242. The plurality of negative electrodes 240 are stacked, for example, in such a manner that the end portions of the side on which the negative electrode active material layer 244 is not formed are directed in substantially the same direction.

[0207] As shown in FIG. 8, the stacked structure 760 includes a plurality of positive electrodes 220 and a plurality of negative electrodes 240. The plurality of positive electrodes 220 are stacked in the direction of the thickness of the stacked structure 760. The plurality of negative electrodes 240 are stacked in the direction of the thickness of the stacked structure 760. Figure 8 As shown in FIG. 8, the stacked structure 760 includes a plurality of positive electrodes 220 and a plurality of negative electrodes 240. The plurality of positive electrodes 220 are stacked in the direction of the thickness of the stacked structure 760. The plurality of negative electrodes 240 are stacked in the direction of the thickness of the stacked structure 760.

[0208] In the present embodiment, the lead wire 822 and the sub-lead wire 824 sandwich and support the end portion of the positive electrode current collector 222 of each of the plurality of positive electrodes 220 and / or the vicinity of the end portion. As described above, the positive electrode active material layer 224 is not formed in the vicinity of at least one end portion of each of the plurality of positive electrodes 220. The lead wire 822 and the sub-lead wire 824 are disposed so as to sandwich the plurality of positive electrode current collectors 222 that are stacked. Note that in other embodiments, the sub-lead wire 824 can not be used.

[0209] In the positive electrode connecting portion 820, the plurality of positive electrodes 220 can also be physically joined by welding. For example, the plurality of positive electrode current collectors 222 that are stacked are physically joined by welding, and the end portions of the plurality of positive electrode current collectors 222 and / or the vicinity of the end portions are integrated. Thus, the plurality of positive electrodes 220 are physically joined. In the end portions of the plurality of positive electrode current collectors 222 and / or the vicinity of the end portions, the plurality of positive electrode current collectors 222 can also be integrated with the lead wire 822 and / or the sub-lead wire 824. For example, in the case where the lead wire 822 and the sub-lead wire 824 contain metal, in the above-described welding process, the plurality of conductive layers 442 and the plurality of conductive layers 444 contained in each of the plurality of positive electrode current collectors 222 are integrated with the lead wire 822 and the sub-lead wire 824. As the welding method, ultrasonic welding, resistance welding, laser welding, and the like are exemplified.

[0210] In the present embodiment, details of the stacked structure 760 are described taking as an example a case where the plurality of positive electrode current collectors 222 of the plurality of positive electrodes 220 are physically joined by welding the regions (sometimes referred to as welding regions) in the vicinity of the end portions of the positive electrode current collectors 222 of the plurality of positive electrodes 220. Note that in other embodiments, the welding regions can also be provided to include the end portions of the positive electrode current collectors 222 of the plurality of positive electrodes 220.

[0211] For example, as described in relation to Figure 4 , Figure 5 or Figure 6 , each of the plurality of positive electrode current collectors 222 has the support layer 420 and the conductive layer 442 and the conductive layer 444 formed on both faces of the support layer 420. The conductive layer 442 and the conductive layer 444 are electrically connected, for example, by the conductive material 546 and / or the conductive layer 642. The composition or material of the support layer 420 can be the same or different between each of the plurality of positive electrode current collectors 222. The composition or material of the support layer 420 of one positive electrode current collector 222 can be the same as or different from the composition or material of the support layer 420 of another positive electrode current collector 222.

[0212] In the present embodiment, the welding region is provided, for example, at least a part of the region in the vicinity of the end portions of the plurality of positive electrode current collectors 222 and sandwiched by the lead wire 822 and the sub-lead wire 824. The planar size of the sub-lead wire 824 can also be larger than the planar size of the welding region. The planar size of the lead wire 822 can also be larger than the planar size of the sub-lead wire 824.

[0213] The lead wire 822 is composed of, for example, a plate-shaped conductive material. The lead wire 822 can contain metal or can be substantially composed of metal. The thickness of the lead wire 822 can be 1 to 300 μm, preferably 5 to 200 μm, and further preferably 10 to 50 μm.

[0214] The material of the sub lead 824 is not particularly limited. The sub lead 824 can include metal and can substantially consist of metal. The sub lead 824 consists of, for example, at least any one selected from the group consisting of aluminum, nickel, stainless steel, copper, and alloys thereof. The sub lead 824 can also consist of a resin material such as polypropylene, polyimide, or the like. The thickness of the sub lead 824 can also be 1 to 300 μm, preferably 5 to 200 μm, and further preferably 10 to 50 μm.

[0215] Similarly, the stacked structure 760 is provided with a negative electrode connecting portion 840 that electrically connects the plurality of negative electrodes 240. According to the present embodiment, the negative electrode connecting portion 840 has a lead 842 that sandwiches and supports a portion of the plurality of negative electrodes 240 and a sub lead 844. Thereby, the strength of the joint portions of the plurality of negative electrodes 240 is increased.

[0216] In the present embodiment, the lead 842 and the sub lead 844 sandwich and support the end portions of the negative electrode current collectors 242 of the plurality of negative electrodes 240 and / or the vicinity of the end portions. As described above, the negative electrode active material layer 244 is not formed in the vicinity of the end portion of at least one of the plurality of negative electrodes 240. The lead 842 and the sub lead 844 are provided so as to sandwich the plurality of negative electrode current collectors 242 that are stacked. Note that, in other embodiments, the sub lead 844 can not be used.

[0217] In the negative electrode connecting portion 840, the plurality of negative electrodes 240 can be physically joined by welding. For example, the plurality of negative electrode current collectors 242 that are stacked are physically joined by welding, and thereby the end portions of the plurality of negative electrode current collectors 242 and / or the vicinity of the end portions are integrated. Thereby, the plurality of negative electrodes 240 are physically joined. It can also be that, in the end portions of the plurality of negative electrode current collectors 242 and / or the vicinity of the end portions, the plurality of negative electrode current collectors 242 are integrated with the lead 842 and / or the sub lead 844. For example, in the case where the lead 842 and the sub lead 844 include metal, in the above-described welding process, the plurality of conductive layers 442 and the plurality of conductive layers 444 included in each of the plurality of negative electrode current collectors 242 are integrated with the lead 842 and the sub lead 844. As the welding method, ultrasonic welding, resistance welding, laser welding, or the like is exemplified.

[0218] According to the present embodiment, details of the stacked structure 760 are described taking as an example a case where the plurality of negative electrode current collectors 242 of the plurality of negative electrodes 240 are physically joined by welding of regions (sometimes referred to as welding regions.) in the vicinity of the end portions of the negative electrode current collectors 242 of the plurality of negative electrodes 240. Note that, in other embodiments, the welding regions can be provided so as to include the end portions of the negative electrode current collectors 242 of the plurality of negative electrodes 240.

[0219] For example, as described above, the plurality of negative electrodes 240 are electrically connected by the negative electrode connecting portion 840. The negative electrode connecting portion 840 is provided with the lead 842 and the sub lead 844. The lead 842 and the sub lead 844 are provided so as to sandwich the plurality of negative electrodes 240. The plurality of negative electrodes 240 are physically joined by welding of the end portions of the negative electrode current collectors 242 of the plurality of negative electrodes 240 and / or the vicinity of the end portions. The plurality of negative electrodes 240 are electrically connected by the lead 842 and the sub lead 844. Figure 4 ,Figure 5 or Figure 6 As described above, each of the plurality of negative current collectors 242 has the support layer 420 and the conductive layer 442 and the conductive layer 444 formed on both surfaces of the support layer 420. The conductive layer 442 and the conductive layer 444 are electrically connected, for example, by the conductive material 546 and / or the conductive layer 642. The composition or material of the support layer 420 can be the same or different between each of the plurality of negative current collectors 242. The composition or material of the support layer 420 of one negative current collector 242 can be the same or different from the composition or material of the support layer 420 of another negative current collector 242.

[0220] In the present embodiment, the welding region is, for example, at least a part of a region in the vicinity of the end portion of each of the plurality of negative current collectors 242 and sandwiched by the lead 842 and the sub-lead 844. The planar size of the sub-lead 844 can be larger than the planar size of the welding region. The planar size of the lead 842 can be larger than the planar size of the sub-lead 844.

[0221] The lead 842 is composed of, for example, a plate-shaped conductive material. The lead 842 can contain metal or can be substantially composed of metal. The thickness of the lead 842 can be 1 to 300 μm, preferably 5 to 200 μm, and further preferably 10 to 50 μm.

[0222] The material of the sub-lead 844 is not particularly limited. The sub-lead 844 can contain metal or can be substantially composed of metal. The sub-lead 844 is composed of, for example, at least one selected from the group consisting of aluminum, nickel, stainless steel, copper, and alloys thereof. The sub-lead 844 can be composed of a resin material such as polypropylene or polyimide. The thickness of the sub-lead 844 can be 1 to 300 μm, preferably 5 to 200 μm, and further preferably 10 to 50 μm.

[0223] The lead 822 can be an example of one of the first support member and the second support member. The sub-lead 824 can be an example of the other of the first support member and the second support member. The lead 842 can be an example of one of the first support member and the second support member. The sub-lead 844 can be an example of the other of the first support member and the second support member. The laminated structure 760 can be an example of the electrode structure. The plurality of positive current collectors 222 included in the laminated structure 760 can be an example of a plurality of sheet materials laminated. The plurality of negative current collectors 242 included in the laminated structure 760 can be an example of a plurality of sheet materials laminated.

[0224] The positive current collector 222 that contacts the lead 822 among the plurality of positive current collectors 222 stacked in the positive terminal connection portion 820 can be an example of either the first sheet material or the second sheet material. The positive current collector 222 that contacts the sub-lead 824 among the plurality of positive current collectors 222 stacked in the positive terminal connection portion 820 can be an example of either the first sheet material or the second sheet material.

[0225] The negative current collector 242 that contacts the lead 842 among the plurality of negative current collectors 242 stacked in the negative terminal connection portion 840 can be an example of either the first sheet material or the second sheet material. The negative current collector 242 that contacts the sub-lead 844 among the plurality of negative current collectors 242 stacked in the negative terminal connection portion 840 can be an example of either the first sheet material or the second sheet material.

[0226] Alternatively, the plurality of positive electrodes 220 in the stacked structure 760 may be an example of a first electrode and a second electrode, and the plurality of negative electrodes 240 in the stacked structure 760 may be an example of a third electrode and a fourth electrode. Alternatively, the plurality of positive electrodes 220 in the stacked structure 760 may be an example of a third electrode and a fourth electrode, and the plurality of negative electrodes 240 in the stacked structure 760 may be an example of a first electrode and a second electrode. Alternatively, the plurality of diaphragms 230 in the stacked structure 760 may each be an example of a first diaphragm, a second diaphragm, or a third diaphragm.

[0227] (An example of another implementation)

[0228] In this embodiment, the details of the laminated structure 760 are described using the case where the laminated structure 760 includes a positive electrode connection portion 820 and a negative electrode connection portion 840 as an example. However, the laminated structure 760 is not limited to this embodiment. In other embodiments, the laminated structure 760 may also include at least one of the positive electrode connection portion 820 and the negative electrode connection portion 840.

[0229] In this embodiment, the details of the positive electrode connection portion 820 are described using the case where multiple positive current collectors 222 in the positive electrode connection portion 820 are supported by leads 822 and sub-leads 824 as an example. However, the positive electrode connection portion 820 is not limited to this embodiment. In other embodiments, the positive electrode connection portion 820 may not have sub-leads 824. In this case, the multiple positive current collectors 222 are supported by leads 822.

[0230] In the present embodiment, details of the negative electrode connecting portion 840 are described taking as an example a case in which the plurality of negative electrode current collectors 242 in the negative electrode connecting portion 840 are supported by the lead wire 842 and the sub lead wire 844. However, the negative electrode connecting portion 840 is not limited to the present embodiment. In other embodiments, the negative electrode connecting portion 840 can not have the sub lead wire 844. In this case, the plurality of negative electrode current collectors 242 are supported by the lead wire 842.

[0231] Figure 9 An example of a manufacturing method of the battery core 112 is schematically shown. In the present embodiment, a method of producing the battery core 112 provided with the laminated structure 760 is described. According to the present embodiment, first, in step 912 (sometimes, the step is omitted as S.), a plurality of positive electrodes 220 and a plurality of negative electrodes 240 are prepared. Details of the method of preparing the positive electrode 220 or the negative electrode 240 will be described later. Further, in S914, a plurality of separators 230 are prepared. Next, in S920, the positive electrode 220, the separator 230, and the negative electrode 240 are sequentially laminated. Thereby, the laminated structure 760 is produced.

[0232] Next, in S932, the plurality of positive electrodes 220 of the laminated structure 760 are electrically connected. Further, in S934, the plurality of negative electrodes 240 of the laminated structure 760 are electrically connected. Thereafter, in S940, the laminated structure 760 is housed inside the positive electrode case 212 and the negative electrode case 214, and the battery core 112 is assembled.

[0233] It can also be that the plurality of positive electrodes 220 prepared in S912 are an example of the first electrode and the second electrode, and the plurality of negative electrodes 240 prepared in S912 are an example of the third electrode and the fourth electrode. It can also be that the plurality of positive electrodes 220 prepared in S912 are an example of the third electrode and the fourth electrode, and the plurality of negative electrodes 240 prepared in S912 are an example of the first electrode and the second electrode. It can also be that the plurality of separators 230 prepared in S914 are each an example of the first separator, the second separator, or the third separator. The laminated structure 760 can also be an example of an electrode structure in which the first electrode, the first separator, the third electrode, the second separator, the second electrode, the third separator, and the fourth negative electrode are sequentially laminated.

[0234] Figure 10 An example of a manufacturing method of the positive electrode 220 is schematically shown. According to the present embodiment, first, in S1010, the positive electrode current collector 222 is prepared. Next, in S1022, the positive electrode slurry containing the positive electrode active material and the solvent is adjusted. Next, in S1024, the positive electrode slurry is applied to the surface of the positive electrode current collector 222. Further, the positive electrode slurry is dried. Thereby, the positive electrode active material layer 224 is formed on the surface of the positive electrode current collector 222.

[0235] Next, in S1030, the positive electrode active material layer 224 and the positive electrode current collector 222 are fixedly joined. More specifically, the positive electrode active material layer 224 and the positive electrode current collector 222 are fixedly joined by applying pressure to the laminated positive electrode active material layer 224 and the positive electrode current collector 222.

[0236] In one embodiment, the pressure in the fixing process can be set or adjusted so that (i) the rate of change of the resistance (specific resistance) of the current collector before and after the pressure is applied to the active material layer and the current collector is within 50% or (ii) the absolute value of the difference between the resistances (specific resistances) of the current collector before and after the pressure is applied to the active material layer and the current collector is 1 [Ω] or less. The pressure in the fixing process can be set or adjusted so that the absolute value of the above difference is less than 1 [Ω]. The pressure in the fixing process is preferably set or adjusted so that the absolute value of the above difference is 500 m[Ω] or less, and further preferably set or adjusted so that the absolute value of the above difference is 100 m[Ω] or less. Thus, the breakage of the conductive layer of the current collector is suppressed. The resistance of the current collector described above can be measured, for example, by a 4-terminal 4-probe method using a low resistivity meter (Lorestar-GX MCP-T700 manufactured by DKK-TOA Corporation).

[0237] In other embodiments, the pressure in the fixing process is set or adjusted so that the value obtained by subtracting (ii) the value of a first voltage measured by applying a current to the conductive layer of the current collector before the pressure is applied from (i) the value of a second voltage measured by applying a current to the conductive layer of the current collector after the pressure is applied is less than 100 mV. Thus, the breakage of the conductive layer of the current collector is suppressed. The first voltage and the second voltage described above are measured, for example, by a low resistivity meter having a voltage value measurement function and an output function. The first voltage and the second voltage described above can be measured, for example, by a 4-terminal 4-probe method using a low resistivity meter (Lorestar-GX MCP-T700 manufactured by DKK-TOA Corporation).

[0238] (Process of physically combining a plurality of electrodes)

[0239] Using Figure 11 , Figure 12 , Figure 13 and Figure 14 , an example of a process of physically combining a plurality of electrodes will be described. For example, as related to Figure 8 and Figure 9As explained, according to one embodiment of the laminated structure 760, in the positive electrode connection portion 820, a plurality of positive electrodes 220 are physically joined by welding. For example, the positive current collectors 222 of each of the plurality of positive electrodes 220 are physically joined by welding. According to one embodiment of the laminated structure 760, in the negative electrode connection portion 840, a plurality of negative electrodes 240 are physically joined by welding. For example, the negative current collectors 242 of each of the plurality of negative electrodes 240 are physically joined by welding.

[0240] In this embodiment, to facilitate understanding of the process of physically joining multiple electrodes, the process of joining a portion of two positive electrodes 220 by welding using a welding apparatus 1120 is used as an example to illustrate the details of the process. Furthermore, the number of electrodes joined by welding is not limited to two. In other embodiments, three or more electrodes may be joined by welding.

[0241] Furthermore, in this embodiment, to facilitate understanding of the process of physically combining multiple electrodes, the details of the process of physically combining multiple electrodes will be explained using the case where one positive electrode 220 has a current collector 1102 and a positive electrode active material layer 224 disposed on at least one side of the current collector 1102, and the other positive electrode 220 has a current collector 1104 and a positive electrode active material layer 224 disposed on at least one side of the current collector 1104 as an example. In this embodiment, the details of the process of physically combining multiple electrodes will be explained using the case where no positive electrode active material layer 224 is formed near the ends of the current collector 1102 and the current collector 1104 as an example.

[0242] Figure 11 An example of the system configuration of the welding apparatus 1120 is shown together with an example of the end and / or vicinity of the current collector 1102 and the current collector 1104. Figure 11 This illustrates an example of a welding process using welding apparatus 1120. More specifically, using... Figure 11 This describes an example of the process by which the welding apparatus 1120 welds a portion of the vicinity of the ends of the current collectors 1102 and 1104 while pressing the ends and vicinity of those ends to create a positive electrode connection portion 820.

[0243] (Welding object)

[0244] In this embodiment, the current collectors 1102 and 1104, which are the objects of the welding process, have associated... Figure 6 The current collector 600 described has the same configuration. (As related) Figure 6As explained above, the current collector 600 has the support layer 420 and the conductive layer 442 and the conductive layer 444 formed on both surfaces of the support layer 420. The plurality of through holes 620 are formed in the current collector 600 so as to penetrate the support layer 420, the conductive layer 442, and the conductive layer 444. The shape of the through holes 620 is not particularly limited. The conductive layer 642 electrically connecting the conductive layer 442 and the conductive layer 444 is formed on the surface of the inner wall portion 622 of at least a part of the plurality of through holes 620.

[0245] In the present embodiment, the support layer 420 of the current collector 1102 and the current collector 1104 contains a thermoplastic resin material (sometimes referred to as a thermoplastic resin). In the present embodiment, the support layer 420 of the current collector 1102 and the current collector 1104 can also be a resin layer substantially composed of a thermoplastic resin material. The support layer 420 of the current collector 1102 and the current collector 1104 can also be an insulating layer substantially composed of a thermoplastic resin material.

[0246] According to the present embodiment, if energy is applied to the support layer 420 of the current collector 1102 and the current collector 1104, the temperature of the support layer 420 rises, and the resin material contained in the support layer 420 softens. If pressure is applied to the current collector 1102 and the current collector 1104 in a state in which the resin material contained in the support layer 420 is softened, the resin material can move inside the support layer 420. The above-mentioned energy is not particularly limited as long as it can raise the temperature of the support layer 420 and / or the resin material contained in the support layer 420. The above-mentioned energy can also be thermal energy.

[0247] The thermoplastic resin material can also be a resin material having a thermal shrinkage rate of 1% or less at 25°C. As the thermoplastic resin material, PE, PET, PAN, PP, PPS, and the like are exemplified.

[0248] The thickness of the support layer 420 of the current collector 1102 and the current collector 1104 can also be 0.5 μm to 20 μm. The above-mentioned thickness of the support layer 420 is preferably 1 μm to 10 μm, and further preferably 2 μm to 8 μm.

[0249] In the present embodiment, the conductive layer 442 and the conductive layer 444 of each of the current collector 1102 and the current collector 1104 contain a metal material. The conductive layer 442 and the conductive layer 444 of each of the current collector 1102 and the current collector 1104 can also be a metal layer substantially composed of a metal material. The metal layer substantially composed of a metal material contains, for example, unavoidable impurities. The metal material contained in the conductive layer 442 and the conductive layer 444 can be a single substance of a metal, or can be an alloy.

[0250] The thickness of the conductive layer 442 and conductive layer 444 of current collector 1102 and current collector 1104 can also be 0.1 μm to 10 μm. The thickness of the conductive layer 442 and conductive layer 444 is preferably 0.1 μm to 5 μm, and more preferably 0.1 μm to 1 μm.

[0251] In this embodiment, the conductive layers 442 and 444 of current collectors 1102 and 1104 are electrically connected. Thus, the welding current applied to the conductive layer 442 of current collector 1102 by the welding apparatus 1120 flows through the conductive layers 442 and 444 of current collector 1102 and 1104.

[0252] The conductive layers 442 and 444 can also be electrically connected in any manner. In one embodiment, a conductive member for electrically connecting the conductive layers 442 and 444 is disposed on the side 426 of the support layer 420. In other embodiments, a conductive member for electrically connecting the conductive layers 442 and 444 is disposed inside the support layer 420.

[0253] In this embodiment, a plurality of through holes 620 are formed in a portion of the current collector 1102, penetrating the support layer 420, conductive layer 442, and conductive layer 444 of the current collector 1102. At least a portion of the plurality of through holes 620 is disposed in the aforementioned welding area. Figure 11 In this context, it is represented as Rw. Therefore, compared to the case where no through holes, grooves, or recesses are formed in the welding area of ​​the support layer 420, the amount of resin material present in the welding area of ​​the support layer 420 is reduced. As a result, the amount of resin material pushed away with the welding of the conductive layers 442 and 444 is reduced, suppressing the volume expansion around the welding area associated with welding.

[0254] According to this embodiment, through holes 620 are also formed in conductive layers 442 and 444. As a result, a portion of the resin material pushed away during the welding of conductive layers 442 and 444 can flow into the interior of the through holes 620 disposed in conductive layers 442 and 444. Consequently, volume expansion around the weld area associated with welding is suppressed. Furthermore, in this case, resin material remains in the weld area after welding.

[0255] At least a part of the plurality of through holes 620 can also be provided in a region adjacent to the soldering region (sometimes referred to as an adjacent region). As described above, with the soldering of the conductive layer 442 and the conductive layer 444, a part of the resin material present in the soldering region before the soldering is pushed away and moves toward the adjacent region. According to the present embodiment, the through hole 620 is formed in the adjacent region, and thus the resin material pushed away with the soldering of the conductive layer 442 and the conductive layer 444 can flow into the inside of the through hole 620 provided in the adjacent region. As a result thereof, the volume expansion of the periphery of the soldering region accompanying the soldering is suppressed.

[0256] At least a part of the plurality of through holes 620 can also be provided in the soldering region and a region adjacent to the soldering region. Thereby, the volume expansion of the periphery of the soldering region accompanying the soldering is further suppressed. Details of the through hole 620 will be described later.

[0257] In the present embodiment, the surface of the inner wall portion 622 of at least a part of the plurality of through holes 620 is provided with a conductive layer 642 that electrically connects the conductive layer 442 and the conductive layer 444. The material that constitutes the conductive layer 642 is only required to be a substance having conductivity, and the kind and structure thereof are not particularly limited. The conductive layer 642 can also contain a metal material. The conductive layer 642 can also be a metal layer substantially composed of a metal material. The metal layer substantially composed of a metal material contains, for example, an unavoidable impurity.

[0258] The metal material contained in the conductive layer 642 can be a single substance of a metal, or can be an alloy. The metal material contained in the conductive layer 642 can be the same as or different from the metal material contained in at least one of the conductive layer 442 and the conductive layer 444. As the metal material, copper, nickel, aluminum, stainless steel, and alloys thereof, and the like are exemplified. As the stainless steel, SUS304, SUS430, and the like are exemplified.

[0259] The conductive layer 642 can also contain a plurality of layers. The plurality of layers can each be composed of a mutually different material. For example, the conductive layer 642 can have a layer for electrically connecting the conductive layer 442 and the conductive layer 444 (sometimes referred to as a target layer) and an auxiliary layer provided between the inner wall portion 622 of the through hole 620 and the target layer. The auxiliary layer is formed in order to assist the conductivity of the target layer or to improve the adhesion of the through hole 620 and the target layer. A protective layer for protecting the target layer can also be formed on the surface of the target layer. As the protective layer, a chromium plating film, a zinc plating film, and the like are exemplified.

[0260] The conductive layer 642 can also have an auxiliary layer, a target layer, and a protective layer. For example, a first layer having nickel as a main component is formed on the surface of the inner wall portion 622 of the through-hole 620, a second layer having copper as a main component is formed on the first layer, and a chromium plating film is formed on the second layer. The thickness of the first layer can be about 0.1 μm, the thickness of the second layer can be about 1 μm, and the thickness of the chromium plating film can be about 0.3 μm.

[0261] As described above, the thickness of the conductive layer 642 of the current collector 1102 and the current collector 1104 can be greater than 0 μm and 5 μm or less. The thickness of the conductive layer 642 described above is preferably 0.1 μm to 3 μm, and further preferably 0.1 μm to 1 μm.

[0262] The conductive layer 642 is formed by a known method. For example, the conductive layer 642 is formed by electroless plating, evaporation, or sputtering. The conductive layer 642 can also be formed by various secondary growth methods, or can be formed by adhering a metal foil to the surface of the inner wall portion 622 of the through-hole 620.

[0263] Similarly, a plurality of through-holes 620 that pass through the support layer 420, the conductive layer 442, and the conductive layer 444 of the current collector 1104 are formed in a portion of the current collector 1104. The surface of the inner wall portion 622 of at least a portion of the plurality of through-holes 620 is provided with a conductive layer 642 that electrically connects the conductive layer 442 and the conductive layer 444. The conductive layer 642 of the current collector 1104 can have the same features as those described in relation to the conductive layer 642 of the current collector 1102.

[0264] (Support member)

[0265] As described above, the conductive layer 442 and the conductive layer 444 according to the present embodiment are formed of a metal thin film, and thus have relatively low strength. Therefore, according to the present embodiment, the lead 822 and the sub-lead 824 described in relation to the current collector 1102 and the current collector 1104 are used to support the current collector 1102 and the current collector 1104. Figure 8 The lead 822 and the sub-lead 824 described in relation to the current collector 1102 and the current collector 1104 are provided to sandwich the current collector 1102 and the current collector 1104 that are stacked. Thus, the breakage of the metal thin film during soldering is suppressed.

[0266] As described above, a conductive member is used as the lead 822. The lead 822 can include metal, or can be substantially composed of metal. On the other hand, a conductive or non-conductive member is used as the sub-lead 824. The sub-lead 824 can include metal, or can be substantially composed of metal.

[0267] Alternatively, the through-holes of the lead 822 and the sub-lead 824 and the laminated collector 1102 and the collector 1104 can be formed before the collectors 1102 and 1104 are welded. Further, a conductive layer that electrically connects the lead 822, the sub-lead 824, the conductive layers 442 and 444 of the collector 1102, and the conductive layers 442 and 444 of the collector 1104 can be formed on the inner wall of the through-holes. The equivalent circle diameter of the through-holes can be 30 μm to 5 mm. The equivalent circle diameter of the through-holes can be larger than the equivalent circle diameter of the through-holes 620 formed in the collectors 1102 and 1104.

[0268] (Welding device)

[0269] In the present embodiment, the welding device 1120 includes a pair of welding heads 1130, a heating power supply 1140, a welding power supply 1150, and a controller 1160. In the present embodiment, the welding device 1120 includes a pair of heating power supplies 1140 that supply electric power to the respective welding heads 1130. In the present embodiment, the welding head 1130 includes a position adjustment section 1132, a heating section 1134, and a welding section 1136.

[0270] In the present embodiment, the welding head 1130 applies energy to the welding object. For example, the welding head 1130 heats the welding object. The welding head 1130 presses the welding object. Thus, the welding head 1130 can apply pressure to the welding object.

[0271] In the present embodiment, the position adjustment section 1132 adjusts the position of the welding head 1130. For example, the position adjustment section 1132 moves the welding head 1130 to the welding region of the welding object. For example, the position adjustment section 1132 presses the welding head 1130 against the welding region of the welding object. Thus, the welding head 1130 presses the welding region of the welding object. As a result, pressure is applied to the welding region of the welding object.

[0272] In the present embodiment, the heating section 1134 applies energy to the softened region of the welding object. Thus, the softened region of the welding object is heated. In the present embodiment, the welding section 1136 applies current and / or voltage to the welding region of the welding object. Thus, the welding region of the welding object is welded.

[0273] In the present embodiment, the heating power supply 1140 supplies electric power to the heating section 1134. In the present embodiment, the welding power supply 1150 supplies electric power to the position adjustment section 1132 and the welding section 1136. In the present embodiment, the controller 1160 controls the operation of the respective sections of the welding device 1120.

[0274] (Welding process)

[0275] Next, an example of a process of welding the current collector 1102 and a part of the current collector 1104 using the welding device 1120 will be described. According to the present embodiment, first, the current collector 1102 and the current collector 1104 to be welded are prepared. In one embodiment, the current collector 1102 and the current collector 1104 having the above-described structure are produced. In another embodiment, the current collector 1102 and the current collector 1104 having the above-described structure are purchased.

[0276] Next, a laminate in which the current collector 1102 and the current collector 1104 are welded so that a part of the current collector 1102 and the current collector 1104 are combined is produced. More specifically, first, the current collector 1102 and the current collector 1104 are laminated. For example, the current collector 1102 and the current collector 1104 are laminated in such a manner that the second plane 424 side of the current collector 1102 and the first plane 422 side of the current collector 1104 are in contact with each other.

[0277] In one embodiment, the plurality of through holes 620 of the current collector 1102 and the plurality of through holes 620 of the current collector 1104 are aligned. In another embodiment, the alignment of the plurality of through holes 620 of the current collector 1102 and the plurality of through holes 620 of the current collector 1104 is not performed.

[0278] Next, the current collector 1102 and the current collector 1104 are reinforced using the lead wire 822 and the sub-lead wire 824. For example, the current collector 1102 and the current collector 1104 and the lead wire 822 and the sub-lead wire 824 are disposed in the working position of the welding device 1120 in such a manner that the lead wire 822 and the sub-lead wire 824 sandwich the welding region of the current collector 1102 and the current collector 1104 or the region around the welding region.

[0279] Next, the welding region of the current collector 1102 and the current collector 1104 is determined. Further, a region including the welding region of the laminated current collector 1102 and the current collector 1104 is determined and the region becomes a region to be subjected to a heat treatment (for example, the softening region indicated as Rs). Figure 11 In one embodiment, the softening region indicated as Rs is determined.

[0280] For example, the user of the welding device 1120 operates the welding device 1120 to input the positions of the welding region and the softening region to the welding device 1120. The controller 1160 of the welding device 1120 controls the position adjustment section 1132 to move the welding head 1130 to an arbitrary position of the softening region of the current collector 1102 and the current collector 1104 (for example, the welding region). The controller 1160 of the welding device 1120 controls the position adjustment section 1132 to bring the welding head 1130 into contact with the softening region of the current collector 1102 and the current collector 1104.

[0281] Next, an area including the soldered region of the laminated current collector 1102 and the current collector 1104 (sometimes referred to as a softened region) is subjected to energy to soften the resin material of the softened region. For example, the controller 1160 of the soldering device 1120 controls the power source for heating 1140 to supply electric power from the power source for heating 1140 to the heating portion 1134. As a result, the heating portion 1134 raises the temperature of the soldering tip 1130. As a result thereof, the softened region of the current collector 1102 and the current collector 1104 is subjected to heat energy from the soldering tip 1130.

[0282] As described above, in the present embodiment, the support layer 420 of the current collector 1102 and the current collector 1104 contains a thermoplastic resin. If the softened region of the current collector 1102 and the current collector 1104 is subjected to heat energy, the thermoplastic resin provided to the softened region is softened.

[0283] Next, the soldered region of at least a portion of the softened region is pressed. For example, the controller 1160 of the soldering device 1120 controls the position adjustment portion 1132 to press the soldering tip 1130 against the soldered region.

[0284] For example, the controller 1160 controls the position adjustment portion 1132 to bring the conductive layer 442 and the conductive layer 444 of each of the current collector 1102 and the current collector 1104 to a distance at which soldering is possible. At this time, pressure is also applied to the thermoplastic resin provided between the conductive layer 442 and the conductive layer 444. According to the present embodiment, the thermoplastic resin is softened and has moderate fluidity. Therefore, if appropriate pressure is applied to the thermoplastic resin, the thermoplastic resin moves toward the inside of the through-hole 620 formed in the conductive layer 442 and the conductive layer 444 of the soldered region and / or the outside of the soldered region.

[0285] The controller 1160 of the soldering device 1120 can also control the position adjustment portion 1132 to apply pressure to the laminated current collector 1102 and the current collector 1104 in a manner in which the softened resin material flows into the inside of the through-hole 620 provided to at least a portion of the softened region and / or the soldered region. As a result, the volume expansion of the periphery of the soldered region accompanying soldering is significantly suppressed.

[0286] The controller 1160 can also control the position adjustment portion 1132 to apply pressure to the laminated current collector 1102 and the current collector 1104 in a manner in which the softened resin material breaks the conductive layer 642 of the surface of the inner wall portion 622 of the through-hole 620 provided to at least a portion of the softened region and / or the soldered region and flows into the inside of the through-hole 620. As a result, the volume expansion of the periphery of the soldered region accompanying soldering is significantly suppressed.

[0287] Alternatively, the controller 1160 of the welding device 1120 controls the position adjustment section 1132 to apply pressure to the laminated current collector 1102 and the current collector 1104 in a manner in which a portion of the conductive layer 442 and the conductive layer 444 of the current collector 1102 forms a region in which each metal layer has a corrugated shape or a shape in which wrinkles are gathered (sometimes referred to as a concave-convex region). Thus, the breakage of the conductive layer 442 and the conductive layer 444 accompanying welding is suppressed.

[0288] Alternatively, the controller 1160 of the welding device 1120 controls the position adjustment section 1132 to apply pressure to the laminated current collector 1102 and the current collector 1104 in a manner in which a portion of the conductive layer 442 and the conductive layer 444 of the current collector 1104 forms a region in which each metal layer has a corrugated shape or a shape in which wrinkles are gathered (sometimes referred to as a concave-convex region). Thus, the breakage of the conductive layer 442 and the conductive layer 444 accompanying welding is suppressed.

[0289] Next, an electric current and / or a voltage is applied to the pressed welding region. Thus, the conductive layer 442 and the conductive layer 444 of each of the current collector 1102 and the current collector 1104 are welded. Further, for example, the conductive layer 444 of the current collector 1102 and the conductive layer 442 of the current collector 1104 are welded. As a result, a laminate in which a portion of each of the conductive layer 442 and the conductive layer 444 of the current collector 1102 and the current collector 1104 is integrated is produced.

[0290] For example, the controller 1160 of the welding device 1120 controls the welding power source 1150 to supply electric power from the welding power source 1150 to the welding section 1136. Thus, an electric current and / or a voltage is applied to the pressed welding region, and a welding current flows in the conductive layer 442 and the conductive layer 444 of each of the current collector 1102 and the current collector 1104. At this time, the controller 1160 of the welding device 1120 can control the position adjustment section 1132 and the welding power source 1150 to further press the welding region while applying an electric current and / or a voltage to the welding region.

[0291] According to the present embodiment, in each of the current collector 1102 and the current collector 1104, the conductive layer 442 and the conductive layer 444 are electrically connected by the conductive layer 642. Thus, a welding current flows in the conductive layer 442 and the conductive layer 444 of the current collector 1102 and the conductive layer 442 and the conductive layer 444 of the current collector 1104. As a result, in at least a portion of the welding region, the four conductive layers are integrated.

[0292] Thus, a laminate in which the conductive layers 442 and 444 of the current collector 1102 and the conductive layers 442 and 444 of the current collector 1104 are integrated at the vicinity of the end portion of one of the current collectors 1102 and 1104 is produced. The thermoplastic resin can also exist in the region in which the conductive layers 442 and 444 are integrated (sometimes referred to as the integrated region). The voids can also exist in the integrated region. Thus, a laminate in which at least one of the thermoplastic resin and the voids is dispersed in the interior of the metal that is integrated can also be produced.

[0293] In the integrated region, the conductive layers 442 and 444 can also have a shape that is different from that before welding. Likewise, the thermoplastic resin contained in the support layer 420 can also have a shape that is different from that before welding. A portion of the integrated region can also include the conductive layers 442, 444, and / or the support layer 420 that maintain almost the same shape as before welding.

[0294] In the case where the lead wire 822 is composed of metal, a laminate in which the lead wire 822, the conductive layers 442 and 444 of the current collector 1102, and the conductive layers 442 and 444 of the current collector 1104 are integrated can also be produced. In this case, the integrated region indicates a region in which a portion of the lead wire 822, the conductive layers 442 and 444 are integrated. Likewise, in the case where the lead wire 822 and the sub-lead wire 824 are composed of metal, a laminate in which the lead wire 822, the conductive layers 442 and 444 of the current collector 1102, the conductive layers 442 and 444 of the current collector 1104, and the sub-lead wire 824 are integrated can also be produced. In this case, the integrated region indicates a region in which a portion of the lead wire 822, the conductive layers 442 and 444, and the sub-lead wire 824 are integrated.

[0295] As described above, a plurality of through-holes 620 are formed in the welding region of the current collector 1102. Likewise, a plurality of through-holes 620 are formed in the welding region of the current collector 1104. At the time of welding, a portion of the plurality of through-holes 620 is filled with the metal contained in the conductive layers 442, 444, and / or 642. Thus, a portion of the plurality of through-holes 620 disappears, or the volume of the voids of a portion of the plurality of through-holes 620 decreases. Likewise, at the time of welding, a portion of the plurality of through-holes 620 is filled with the thermoplastic resin contained in the support layer 420. Thus, a portion of the plurality of through-holes 620 disappears, or the volume of the voids of a portion of the plurality of through-holes 620 decreases. As a result thereof, depending on the conditions and / or the state at the time of welding, the thermoplastic resin and / or the voids sometimes remain in the integrated region.

[0296] In addition, the integrated region can not contain the thermoplastic resin, and the integrated region can not contain the void. For example, by adjusting the degree of pressing and / or the magnitude of the welding current at the time of welding, a laminate in which the integrated region does not contain the thermoplastic resin and / or the void can be produced.

[0297] (Resin content ratio in the integrated region)

[0298] The ratio of the volume of the resin present in the integrated region to the volume of the metal present in the integrated region (sometimes referred to as the resin content ratio in the integrated region) can also be 0%, and can also be 0.1 to 50%. The resin content ratio described above is preferably 0.1 to 50%, more preferably 1 to 30%, and further preferably 5 to 20%.

[0299] In the case where the lead 822 and / or the sub-lead 824 is produced so as to be composed of metal, and the lead 822 and / or the sub-lead 824, the conductive layers 442 and 444 of the current collector 1102, and the conductive layers 442 and 444 of the current collector 1104 are integrated, the resin content ratio in the integrated region can be derived as the ratio of the volume of the resin present in the integrated region to the volume of the metal originating from the conductive layers 442 and 444 present in the integrated region. The volume of the metal originating from the conductive layers 442, 444, and / or 642 can also be the volume of the same kind of metal as the component (sometimes referred to as the main component) that mainly constitutes the conductive layers 442, 444, and / or 642.

[0300] For example, in the case where the main component of the lead 822 and / or the sub-lead 824, the main component of the conductive layers 442 and 444 of the current collector 1102, and the main component of the conductive layers 442 and 444 of the current collector 1104 are different, the boundary between the metal originating from the lead 822 and / or the sub-lead 824 and the metal originating from the conductive layers 442 and / or 444 is determined by observing a cross section obtained by cutting the integrated region with a plane substantially parallel to the stacking direction (the up-down direction in the integrated region) of the plurality of current collectors integrated. Figure 11 In the case where the main component of the lead 822 and / or the sub-lead 824, the main component of the conductive layers 442, 444, and 642 of the current collector 1102, and the main component of the conductive layers 442, 444, and 642 of the current collector 1104 are different, the same applies.

[0301] For example, in a case where the main component of the lead 822 and / or the sub-lead 824 is the same as or similar to the main component of the conductive layer 442 and / or the conductive layer 444, it is also considered that it is difficult to determine the position of the above-described boundary based on the observation of the cross section of the integrated region. In this case, the position of the above-described boundary can also be inferred based on the position of the boundary between the lead 822 and / or the sub-lead 824 and the conductive layer 442 and / or the conductive layer 444 in the adjacent region where the metal originating from the lead 822 and / or the sub-lead 824 and the metal originating from the conductive layer 442 and / or the conductive layer 444 are not integrated.

[0302] The above-described resin content ratio can also be 5 to 50%. The above-described resin content ratio is preferably 5 to 30%, and more preferably 5 to 20%. According to the present embodiment, the through hole 620 is formed in the softened region and / or the soldered region. Therefore, compared to a case where the through hole 620 is not formed in the softened region and / or the soldered region, the above-described resin content ratio can be larger. Further, a larger resin content ratio can indicate that the through hole 620 is formed in the softened region and / or the soldered region.

[0303] If the resin content exceeds 50%, the soldering is insufficient, and the durability of the soldered portion decreases. Further, if the resin content exceeds 50%, the conductivity between the lead 822 and the sub-lead 824 decreases, and the resistance increases. On the other hand, in a case where the integrated region contains an appropriate amount of resin, the resin can contribute to the strength assurance of the integrated region. Further, in this case, the integrated region contains an adequate amount of the conductive material, and thus, the conductivity of the integrated region is ensured.

[0304] The proportion of the volume of the thermoplastic resin originating from the support layer 420 in the resin present in the integrated region with respect to the volume of the metal originating from the conductive layer 442, the conductive layer 444, and / or the conductive layer 642 in the metal present in the integrated region can also be 5 to 50%. The above-described proportion can also be 10 to 50%, can also be 10 to 40%, and can also be 5 to 30%. As described above, for example, in a case where the main component of the lead 822 and / or the sub-lead 824 is different from the main component of the conductive layer 442 and the conductive layer 444 of the current collector 1102 and the main component of the conductive layer 442 and the conductive layer 444 of the current collector 1104, the volume of the metal originating from the conductive layer 442, the conductive layer 444, and / or the conductive layer 642 in the metal present in the integrated region can be comparatively easily determined based on the observation using a scanning electron microscope.

[0305] As described above, the resin content ratio in the integrated region can be observed by using a scanning electron microscope (SEM) to observe, for example, the cross section of the integrated region in the direction of the stacking of the plurality of current collectors that are integrated (the direction of the thickness of the integrated region) (see FIG. 6B). Figure 11a face that is substantially parallel to the up-and-down direction in the integrated region. The cross section obtained by cutting the integrated region with the substantially parallel face that is substantially parallel to the extending direction of the plurality of current collectors (the left-and-right direction in the integrated region) is determined. The cross section described above (in other words, the observation face for the SEM) can also be a cross section obtained by cutting the integrated region with a face that is substantially parallel to the up-and-down direction in the integrated region. Figure 11 a face that is substantially parallel to the up-and-down direction in the integrated region. The cross section obtained by cutting the integrated region with the substantially parallel face that is substantially parallel to the extending direction of the plurality of current collectors (the left-and-right direction in the integrated region) is determined. The cross section described above (in other words, the observation face for the SEM) can also be a cross section obtained by cutting the integrated region with a face that is substantially parallel to the up-and-down direction in the integrated region. Figure 11 a face that is substantially perpendicular to the left-and-right direction in the integrated region. The cross section obtained by cutting the integrated region with the substantially perpendicular face is determined. Figure 11 a face that is substantially perpendicular to the paper face in the integrated region. The cross section obtained by cutting the integrated region with the substantially perpendicular face is determined.

[0306] The cross section described above can also be a face that passes through the substantially center of the integrated region. The substantially center of the integrated region is determined by observing, for example, the surface of one side (for example, the first plane 422) of the plurality of current collectors that are integrated by visual observation. The surface described above can also be the surface on the side of the first plane 422 of the current collector that is disposed on the uppermost surface, or the surface on the side of the second plane 424 of the current collector that is disposed on the lowermost surface.

[0307] In the stage of cutting the integrated region of the laminate in order to observe the cross section of the laminate using the SEM, the approximate position of the outer edge of the integrated region is determined, for example, by confirming the welding marks by visual observation. In addition, the accurate position of the outer edge of the integrated region is determined, for example, by observing the cross section of the integrated region of the laminate after cutting the integrated region using the SEM.

[0308] According to an embodiment, by appropriately adjusting the magnification of the SEM image in the vicinity of the outer edge of the integrated region, the region in which the plurality of conductive layers are integrated and the region in which the plurality of conductive layers only contact without being integrated can be distinguished by visual observation. Thus, the position of the outer edge (sometimes referred to as the end portion) of the integrated region can be determined.

[0309] According to another embodiment, the position of the outer edge of the integrated region is determined based on the length (sometimes referred to as the thickness) of the laminate in the stacking direction of the plurality of current collectors. For example, the position at which the thickness thereof becomes 1.1 times the average of the thickness in the vicinity of the center of the integrated region is determined as the end portion of the integrated region. The thickness in the vicinity of the center of the integrated region is determined, for example, by averaging the thickness at the positions of three portions in the SEM image in the vicinity of the center of the integrated region. The measurement interval is appropriately set to obtain the above number of measurement values.

[0310] In the case where a plurality of positions exist that have a thickness of 1.1 times the average of the thickness of the integrated region, the end portion of the integrated region can also be the position closest to the center of the integrated region among the plurality of positions. In the case where the plurality of current collectors are welded using a lead and using a sub-lead, the thickness of the integrated region can also be the distance of the lead and the sub-lead.

[0311] The resin content in the integrated region can be derived, for example, as the ratio of the area of ​​thermoplastic resin in the SEM image to the area of ​​metal in the SEM image. Alternatively, the resin content in the integrated region can be derived as the average of the resin content obtained from observations at different SEM positions within a single cross-section. For example, first, five resin content values ​​corresponding to five SEM images are derived. Next, the three values ​​of the five resin content measurements, excluding the maximum and minimum values, are averaged. This determines the resin content in the integrated region. One of the multiple SEM images can also be an image representing the approximate center of the integrated region.

[0312] (Porosity in the integrated area)

[0313] The ratio of the volume of voids in the integrated region to the volume of the metal (sometimes referred to as the porosity in the integrated region) can also be 0 to 10%. The porosity in the integrated region is preferably 0 to 10%, more preferably 0.1 to 8%, and even more preferably 0.1 to 5%. The porosity in the integrated region can also exceed 10%, but if the porosity increases, the strength and conductivity of the integrated region decrease. Therefore, the porosity in the integrated region is preferably 10% or less.

[0314] According to this embodiment, through holes 620 are formed in the softened region and / or the welded region. Therefore, compared with the case where no through holes 620 are formed in the softened region and / or the welded region, the porosity can be increased. Furthermore, a relatively large porosity indicates that through holes 620 are formed in the softened region and / or the welded region.

[0315] The porosity in the integrated region can be observed, for example, by using a scanning electron microscope (SEM) to examine the stacking orientation of multiple current collectors integrated with the substrate (for...). Figure 11 The porosity of the integrated region is determined by the cross-section obtained by cutting the integrated region with a roughly parallel plane in the vertical direction. The porosity of the integrated region is determined, for example, by a process similar to the resin content of the integrated region.

[0316] As described above, the aforementioned laminates constitute a part of the laminated structure 760. (As related...) Figure 8 As explained, the stacked structure 760 has a structure in which the first positive electrode 220, the first separator 230, the first negative electrode 240, the second separator 230, the second positive electrode 220, the third separator 230, and the second negative electrode 240 are stacked sequentially.

[0317] In the present embodiment, the positive electrode connecting portion 820 of the laminate including the current collector 1102 and the current collector 1104 is provided in the vicinity of the end portions of the positive electrode 220 including the current collector 1102 and the positive electrode 220 including the current collector 1104. Thus, according to the present embodiment, the two positive electrodes 220 are integrated in the vicinity of the end portions. Thereby, compared with a case where the tabs are respectively provided for the plurality of current collectors and the tabs of the plurality of current collectors are electrically connected by a wiring, the mass of the battery cell 112 is reduced. As a result thereof, the battery cell 112 having a large mass energy density is obtained.

[0318] In the present embodiment, before the softening treatment or the pressing treatment of the thermoplastic resin described above is performed, the current collector 1102 and the current collector 1104 are reinforced using the lead 822 and the sub-lead 824. Thereby, the breakage of the conductive layer 442 and / or the conductive layer 444 due to the pressure applied at the time of welding is suppressed.

[0319] The current collector 1102 can be an example of the sheet material, the first sheet material, or the second sheet material. The current collector 1104 can be an example of the sheet material, the first sheet material, or the second sheet material.

[0320] An example of the plurality of through holes 620 provided in the current collector 1102 is described using Figure 12 and Figure 13 An example of the plan view of the current collector 1102 is shown in Figure 12 An example of the cross-sectional view of the current collector 1102 is shown in Figure 13 An example of the cross-sectional view of the current collector 1102 is shown in

[0321] As shown in Figure 12 In the present embodiment, the diameter d (for example, the equivalent circle diameter) of each of the plurality of through holes 620 can be 15 μm to 150 μm. In a case where the diameter d is less than 15 μm, the thermoplastic resin does not easily flow into the inside of the through hole 620. Further, the volume of the through hole 620 is small, and thus the volume expansion rate of the welded laminate becomes large. On the other hand, if the diameter d exceeds 150 μm, the strength of the current collector 1102 becomes small, and the current collector 1102 easily breaks at the time of welding.

[0322] In the present embodiment, the pitch P of the two adjacent through holes 620 can also be 30 μm to 250 μm. In the case where the pitch P is less than 30 μm, the strength of the current collector 1102 becomes small, and the current collector 1102 is easily broken at the time of welding. In addition, the resistance of the current collector 1102 becomes large. On the other hand, if the pitch P exceeds 250 μm, the total amount of the thermoplastic resin present in the welding region can also be relatively large. Therefore, the volume expansion rate of the welded laminate can become large. In this regard, by appropriately forming the through holes 620 in the welding region, the total amount of the thermoplastic resin present in the welding region before welding is reduced. As a result thereof, the volume expansion of the adjacent region in conjunction with welding can be suppressed.

[0323] The length TL in the extending direction of the current collector 1102 can also be larger than the length HL of the region (sometimes referred to as a through hole band) in which the plurality of through holes 620 are formed, and TL and HL can also be substantially the same. The length TW in the direction (sometimes referred to as a width direction) substantially perpendicular to the extending direction of the current collector 1102 can also be larger than the length HW in the width direction of the through hole band, and TW and HW can also be substantially the same.

[0324] In the present embodiment, the above-described welding region is provided inside the through hole band. At least a part of the above-described softening region is provided inside the through hole band. For example, the above-described adjacent region is provided inside the through hole band. The above-described softening region can also be provided inside the through hole band.

[0325] The size of the softening region Rs can also be determined based on the size of the welding region Rw. The size of the softening region Rs is determined so that, for example, the ratio of the area Ss of the softening region Rs in the first plane 422 or the second plane 424 of the support layer 420 to the area Sw of the welding region Rw in the first plane 422 or the second plane 424 of the support layer 420 is represented by the following mathematical expression (1). Thereby, the volume of the through holes 620 present inside the softening region Rs is the same as or more than the volume of the thermoplastic resin present inside the welding region Rw.

[0326] (Mathematical expression 1)

[0327] Ss / Sw ≥ (1 - ε w + ε out ) / ε out

[0328] In the mathematical expression 1, ε w represents the void ratio of the plurality of through holes in the welding region Rw. ε ou t represents the void ratio of the plurality of through holes in the region of the softening region Rs other than the welding region Rw. ε w and ε outIt is the porosity at the softening temperature.

[0329] The porosity ε of multiple through holes in the welded area Rw w It can also be above 10% at the softening treatment temperature. The porosity ε at the softening treatment temperature. w Preferably, it is 20% or more, and more preferably 30% or more.

[0330] like Figure 13 As shown, a conductive layer 642 is formed inside the through-hole 620. Therefore, the diameter dv of the space formed inside the through-hole 620 is smaller than the diameter d of the through-hole 620.

[0331] As described above, the thickness Hd of the conductive layer 642 can also be 0 μm to 5 μm. Preferably, the thickness Hd of the conductive layer 642 is 0.1 μm to 3 μm, and more preferably 0.1 μm to 1 μm.

[0332] As described above, the thickness hr of the support layer 420 can also be 0.5 μm to 20 μm. The thickness hr of the support layer 420 is preferably 1 μm to 10 μm, and more preferably 2 μm to 8 μm.

[0333] As described above, the thickness hm of conductive layer 442 and conductive layer 444 can also be 0.1 μm to 10 μm. The thickness hm of conductive layer 442 and conductive layer 444 is preferably 0.1 μm to 5 μm, and more preferably 0.1 μm to 1 μm.

[0334] Figure 14 This illustrates an example of the process of fabricating a multi-layered structure 760 in which a portion of each of the multiple positive electrode current collectors 222 is integrated. (As related...) Figure 11 As explained, according to this embodiment, firstly, in S1410, a plurality of positive electrodes 220 are prepared. Next, in S1420, the ends of the positive current collectors 222 of the plurality of positive electrodes 220 are stacked. In S1430, the leads 822 and the sub-leads 824 are arranged such that the ends of the positive current collectors 222 on which the leads 822 and the sub-leads 824 are stacked are sandwiched.

[0335] In S1440, energy is applied to the softened region of the stacked positive current collector 222 to soften the thermoplastic resin contained in the support layer 420 of the positive current collector 222. In S1450, the welding region of the stacked positive current collector 222 is pressed to move the softened thermoplastic resin into the interior of the through hole 620 of the positive current collector 222. In S1450, a welding current is applied to the welding region of the stacked positive current collector 222 to weld the conductive layer 442 and the conductive layer 444 of the positive current collector 222.

[0336] Using Figure 15 , Figure 16 , Figure 17 and Figure 18 , details of the positive electrode connecting portion 820 formed with the above-described concavo-convex region are described. In the present embodiment, in order to easily understand the above-described concavo-convex region, details of the positive electrode connecting portion 820 are described taking the case where the lead 822, the three positive electrode current collectors 222, and the sub-lead 824 are integrated by welding as an example. In the present embodiment, the lead 822 and the sub-lead 824 are disposed so as to sandwich the three positive electrode current collectors 222 that are stacked. In addition, the negative electrode connecting portion 840 can have the same structure as the positive electrode connecting portion 820.

[0337] Figure 15 An example of a plan view schematically showing the positive electrode connecting portion 820 after welding is shown. Figure 15 An example of a surface of the two surfaces of the positive electrode connecting portion 820 on which the sub-lead 824 is disposed is schematically shown. Figure 16 and Figure 17 An example of a cross section of the positive electrode connecting portion 820 after welding is schematically shown. Figure 18 An example of the positive electrode current collector 222 including the concavo-convex region 1600 is schematically shown. In the drawing, the xy plane shows a plane that is substantially perpendicular to the stacking direction (z direction in the drawing) of the positive electrode current collector 222.

[0338] As shown in Figure 15 , in the present embodiment, the lead 822 and the sub-lead 824 are disposed so as to sandwich the three positive electrode current collectors 222 at the vicinity of the end portions of the three positive electrode current collectors 222 that are stacked. The sub-lead 824 is formed with an integrated region 1520.

[0339] As described in association with Figure 11 , in a process for integrating a part of a laminate including the lead 822 and the sub-lead 824 and the three positive electrode current collectors 222 by welding, a welding region including the integrated region 1520 is pressed. The sub-lead 824 has a shape that is recessed from the outer edge of the sub-lead 824 toward the integrated region 1520.

[0340] In a region (sometimes referred to as a smooth region) that is sufficiently apart from the integrated region 1520, the surface of the positive electrode current collector 222 has a sufficiently small flatness. The smooth region can also be a region that is sufficiently apart from the end portions of both the lead 822 and the sub-lead 824 and the surface of the positive electrode current collector 222 has a sufficiently small flatness. For example, the flatness of the positive electrode current collector 222 in the smooth region is substantially equal to a value obtained by taking into account the flatness of the sheet or film serving as the support layer 420 and the manufacturing error of the conductive layer 442 and the conductive layer 444.

[0341] On the other hand, in the adjacent region provided between the integrated region and the flat region, the concave-convex region is formed in the conductive layer 442 and the conductive layer 444 of the positive electrode current collector 222 by the resin material pressed out from the integrated region in the above-described welding process. The above-described concave-convex region is formed outside the above-described integrated region 1520. The concave-convex region is provided, for example, adjacent to the integrated region.

[0342] The flatness of the conductive layer 442 in the concave-convex region is greater than the flatness of the conductive layer 442 in the flat region. The ratio of the flatness of the conductive layer 442 in the flat region to the flatness of the conductive layer 442 in the concave-convex region can be 0.5 to 0.9, or 0.5 to 0.8, or 0.5 to 0.75. The above-described ratio can also be 0.7 to 0.8. Thereby, the peeling of the lead wire 822 from the positive electrode current collector 222 can be suppressed. In addition, the above-described deviation can be suppressed.

[0343] Similarly, the flatness of the conductive layer 444 in the concave-convex region is greater than the flatness of the conductive layer 444 in the flat region. The ratio of the flatness of the conductive layer 444 in the flat region to the flatness of the conductive layer 444 in the concave-convex region can be 0.5 to 0.9, or 0.5 to 0.8, or 0.5 to 0.75. The above-described ratio can also be 0.7 to 0.8. Thereby, the peeling of the lead wire 822 from the positive electrode current collector 222 can be suppressed. In addition, the above-described deviation can be suppressed.

[0344] In the present embodiment, the size of the sub-lead wire 824 is smaller than the size of the lead wire 822. In this case, it can also be that (i) the ratio of the flatness of the conductive layer 442 in the flat region to the flatness of the conductive layer 442 in the concave-convex region is 0.5 to 0.9, and (ii) the ratio of the flatness of the conductive layer 444 in the flat region to the flatness of the conductive layer 444 in the concave-convex region is 0.7 to 0.8.

[0345] In the concave-convex region of the conductive layer 442, the conductive layer 442 has a corrugated shape or a shape in which wrinkles are gathered. In the concave-convex region of the conductive layer 442, the conductive layer 442 includes a plurality of peak portions arranged and provided along the in-plane direction of the conductive layer 442 and at least one valley portion. Thereby, wrinkles are formed on the surface of the conductive layer 442.

[0346] In the face (in the drawing, the xy plane.) that is substantially perpendicular to the stacking direction of the positive electrode current collector 222, the concave-convex region of the conductive layer 442 can extend from the end portion of the integrated region 1520 toward a single direction, or can extend toward a plurality of directions. The shape of the concave-convex region in the face that is substantially perpendicular to the stacking direction of the positive electrode current collector 222 can be substantially rectangular, or can be substantially circular, or can be substantially sector-shaped. The shape of the concave-convex region in the face that is substantially perpendicular to the stacking direction of the positive electrode current collector 222 can be substantially concentric circular, or can be substantially concentric polygonal.

[0347] In one embodiment, it can also be that, in a cross section obtained by cutting the conductive layer 442 with a plane (i.e., a first cut surface) that includes the substantially center 1522 of the integrated region 1520 and is substantially parallel to the stacking direction (in the drawing, the z direction.) of the positive electrode current collector 222, a corrugated shape or a shape in which wrinkles are gathered is formed in a portion of the conductive layer 442. In other embodiments, it can also be that, in both (i) a cross section obtained by cutting the conductive layer 442 with the first cut surface and (ii) a cross section obtained by cutting the conductive layer 442 with a plane (i.e., a second cut surface) that includes the substantially center 1522 of the integrated region 1520 and is substantially parallel to the stacking direction (in the drawing, the z direction.) of the positive electrode current collector 222 and is different from the first cut surface, a corrugated shape or a shape in which wrinkles are gathered is formed in a portion of the conductive layer 442.

[0348] Similarly, in the concave-convex region of the conductive layer 444, the conductive layer 444 has a corrugated shape or a shape in which wrinkles are gathered. In the concave-convex region of the conductive layer 444, the conductive layer 444 includes a plurality of peak portions and at least one valley portion that are arranged and disposed along the in-plane direction of the conductive layer 444. As a result, wrinkles are formed on the surface of the conductive layer 444.

[0349] In the face (in the drawing, the xy plane.) that is substantially perpendicular to the stacking direction of the positive electrode current collector 222, the concave-convex region of the conductive layer 444 can extend from the end portion of the integrated region 1520 toward a single direction, or can extend toward a plurality of directions. The shape of the concave-convex region in the face that is substantially perpendicular to the stacking direction of the positive electrode current collector 222 can be substantially rectangular, or can be substantially circular, or can be substantially sector-shaped. The shape of the concave-convex region in the face that is substantially perpendicular to the stacking direction of the positive electrode current collector 222 can be substantially concentric circular, or can be substantially concentric polygonal.

[0350] In one embodiment, the corrugated shape or the shape in which the folds are gathered can be formed in a portion of the conductive layer 444 in a cross section obtained by cutting the conductive layer 444 with a plane including the substantially center 1522 of the integrated region 1520 and substantially parallel to the stacking direction (z direction in the figure) of the positive electrode current collector 222, that is, a first cross section. In other embodiments, the corrugated shape or the shape in which the folds are gathered can be formed in a portion of the conductive layer 444 in both (i) a cross section obtained by cutting the conductive layer 444 with the first cross section and (ii) a cross section obtained by cutting the conductive layer 444 with a plane including the substantially center 1522 of the integrated region 1520 and substantially parallel to the stacking direction (z direction in the figure) of the positive electrode current collector 222 and different from the first cross section, that is, a second cross section.

[0351] The plurality of conductive layers 442 can include the concave-convex region described above, and the plurality of conductive layers 444 can include the concave-convex region described above. The shape of the concave-convex region formed in each of the plurality of conductive layers 442 can be substantially the same or substantially similar, or can be different. The shape of the concave-convex region formed in each of the plurality of conductive layers 444 can be substantially the same or substantially similar, or can be different.

[0352] It is preferable that the number of conductive layers having the concave-convex region described above be more than 30% of the total number of conductive layers included in the laminate. The number of conductive layers having the concave-convex region described above can be more than 80% of the total number of conductive layers included in the laminate. Thus, the variation in the resistance between the conductive layers described above is significantly suppressed.

[0353] Figure 16 and Figure 17 is schematically shown Figure 15 is schematically shown Figure 15 As shown in

[0354] As shown in Figure 16 and Figure 17 In the present embodiment, the three conductive layers 442 included in the three positive electrode current collectors 222 have the concave-convex region 1600. In addition, the two conductive layers 444 included in the three positive electrode current collectors 222 have the concave-convex region 1600. In the present embodiment, the conductive layer 444 in contact with the lead wire 822 does not have the concave-convex region 1600. As shown in Figure 16 In the present embodiment, the concave-convex region 1600 of each conductive layer is formed in a portion of the adjacent region 1620 of the laminate.

[0355] As described above, the adjacent region 1620 of the laminate is disposed between the integrated region 1520 and the smooth region 1640 of the laminate. Alternatively, the adjacent region 1620 of the laminate may be disposed adjacent to the integrated region 1520 of the laminate. Alternatively, the adjacent region 1620 may include at least a portion of the softened region described above.

[0356] The position of the end of the integrated region 1520 is determined by the method described above. As mentioned above, the smooth region 1640 is a region that is sufficiently separated from the end of the integrated region 1520, and is a region where the surface of the stacked positive current collector 222 has sufficiently small flatness. The smooth region 1640 may also be a region whose shape hardly changes before and after the welding process.

[0357] Whether a specific region belongs to the smooth region 1640 is determined, for example, by the following process. First, the thickness of the stacked positive current collector 222 is measured at three locations (sometimes referred to as measurement positions) located outside the integrated region 1520 and along a straight line passing approximately at the center 1522 of the integrated region 1520. The interval between the above-mentioned three measurement positions (sometimes referred to as the measurement interval) is preferably 0.1 mm or more, but this measurement interval can be appropriately set according to the size of the sample.

[0358] If the absolute value of the difference between the maximum and minimum values ​​of the three measurements is less than 5% of the average value of the three measurements, the specific region can be identified as a smooth region 1640. In this case, the thickness Hs of the stacked positive current collector 222 in the smooth region 1640 can also be the average value of the three measurements mentioned above.

[0359] like Figure 17 As shown, in this embodiment, the maximum thickness Hmax of the stacked positive current collector 222 in the adjacent region 1620 of the laminate is greater than the thickness Hs of the stacked positive current collector 222 in the smooth region 1640. The value of Hmax can be 1.0 to 1.5 times the value of Hs, or it can be 1.1 to 1.3 times the value of Hs. When the value of Hmax is within the above-mentioned range, the excessive pressure applied to the solder joint is suppressed. As a result, the strength of the weld is improved.

[0360] Figure 18 schematically shown Figure 16 and Figure 17 An example of a cross-section of one of the three positive current collectors 222 shown. For example... Figure 18As shown in the drawing, the conductive layer 442 of the positive electrode current collector 222 described above includes the uneven region 1600. In the present embodiment, the uneven region 1600 of the conductive layer 442 includes a plurality of peaks and valleys arranged and disposed along the extension direction of the conductive layer 442 in the aforementioned cross section (x direction in the drawing).

[0361] In the present embodiment, the conductive layer 444 of the positive electrode current collector 222 described above also includes the uneven region 1600. In the present embodiment, the uneven region 1600 of the conductive layer 444 includes a plurality of peaks and valleys arranged and disposed along the extension direction of the conductive layer 444 in the aforementioned cross section (x direction in the drawing).

[0362] In the present embodiment, the maximum value Smax of the length of the adjacent peaks and valleys in the uneven region 1600 is greater than the thickness Hf of the single positive electrode current collector 222 in the smooth region 1640. The value of Smax can be 1.1 to 2 times the value of Hf, or 1.2 to 1.5 times the value of Hf.

[0363] In the present embodiment, the maximum value Fmax of the interval of the adjacent two peaks can be 10 to 200 μm, or 20 to 70 μm. The value of Fmax can be 2 to 20 times the value of Hf, or 3 to 10 times the value of Hf.

[0364] The positive electrode current collector 222 has, for example, a thickness of at least 5 to 7 μm. Therefore, by observing the SEM image, the X-ray CT image, or the like, the uneven region formed in conjunction with the welding can be distinguished from the minute unevenness inevitably formed at the time of manufacturing the conductive layer 442 and / or the conductive layer 444.

[0365] In the present embodiment, the number N of the peaks disposed in the uneven region 1600 can be two or more, or three or more. The number N of the peaks is preferably six or more, or ten or more. The greater the number of the peaks, the more the strength of the welding is improved.

[0366] The conductive layer 442 in which the uneven region is formed can be an example of the first metal layer including the uneven region. The extension direction of the conductive layer 442 can be an example of the in-plane direction of the metal layer. The conductive layer 444 in which the uneven region is formed can be an example of the second metal layer including the uneven region. The extension direction of the conductive layer 444 can be an example of the in-plane direction of the metal layer. The peaks of the uneven region 1600 can be an example of the peak portion. The valleys of the uneven region 1600 can be an example of the valley portion.

[0367] Figure 19 An example of the uneven region 1900 is schematically shown. An example of the cross section of one of the three positive electrode current collectors 222 shown in the drawing is schematically shown. Figure 16 and Figure 17 Another example of the cross section of one of the three positive electrode current collectors 222 shown in the drawing is schematically shown. As shown in the drawing, the conductive layer 442 of the positive electrode current collector 222 described above includes the uneven region 1600. In the present embodiment, the uneven region 1600 of the conductive layer 442 includes a plurality of peaks and valleys arranged and disposed along the extension direction of the conductive layer 442 in the aforementioned cross section (x direction in the drawing).Figure 19 As illustrated, the conductive layer 442 of the positive electrode current collector 222 includes the concave-convex region 1900.

[0368] The concave-convex region 1900 of the conductive layer 442 is different from the concave-convex region 1600 described above in that the concave-convex region 1900 has a region in which a peak is not included between adjacent two valleys. Figure 16 to 18 The concave-convex region 1900 of the conductive layer 442 is different from the concave-convex region 1600 described above in that the concave-convex region 1900 has a region in which a peak is not included between adjacent two valleys. Figure 16 to 18 The concave-convex region 1900 of the conductive layer 442 is different from the concave-convex region 1600 described above in that the concave-convex region 1900 has a region in which a peak is not included between adjacent two valleys.

[0369] The concave-convex region 1900 of the conductive layer 442 is different from the concave-convex region 1600 described above in that the concave-convex region 1900 has a region in which a peak is not included between adjacent two valleys. Figure 16 to 18 The concave-convex region 1900 of the conductive layer 442 is different from the concave-convex region 1600 described above in that the concave-convex region 1900 has a region in which a peak is not included between adjacent two valleys.

[0370] Figure 20 Another example of the cross section of the positive electrode connecting portion 820 is schematically illustrated. The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the positive electrode connecting portion 820 has the composite region 2020 disposed between the integration region 1520 and the adjacent region 1620 or a part of the adjacent region 1620. Figure 20 The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the positive electrode connecting portion 820 has the composite region 2020 disposed between the integration region 1520 and the adjacent region 1620 or a part of the adjacent region 1620. Figure 15 to 19 The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the positive electrode connecting portion 820 has the composite region 2020 disposed between the integration region 1520 and the adjacent region 1620 or a part of the adjacent region 1620. Figure 20 The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the positive electrode connecting portion 820 has the composite region 2020 disposed between the integration region 1520 and the adjacent region 1620 or a part of the adjacent region 1620. Figure 15 to 19 The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the positive electrode connecting portion 820 has the composite region 2020 disposed between the integration region 1520 and the adjacent region 1620 or a part of the adjacent region 1620.

[0371] In the composite region 2020 of the laminate, at least a part of the conductive layer 442 and the conductive layer 444 maintain a foil-like shape and are integrated with the metal of the lead 822 and / or the sub-lead 824. For example, in the composite region 2020 of the laminate, the laminate has a solid 2022 formed by melting and solidifying the metal of the lead 822 and / or the sub-lead 824 in a soldering process between the adjacent conductive layer 442 and the conductive layer 444.

[0372] Figure 21 Still another example of the cross section of the positive electrode connecting portion 820 is schematically illustrated. The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the adjacent region 1620 of the positive electrode connecting portion 820 is covered with the sub-lead 824. Figure 21 The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the adjacent region 1620 of the positive electrode connecting portion 820 is covered with the sub-lead 824. Figure 15 to 20 The positive electrode connecting portion 820 described above is different from the positive electrode connecting portion 820 described above in that the adjacent region 1620 of the positive electrode connecting portion 820 is covered with the sub-lead 824. Figure 21The positive electrode connecting portion 820 described above is the same as the positive electrode connecting portion 820 described above except for the above-described difference. Figure 15 to 20 The positive electrode connecting portion 820 described above is the same as the positive electrode connecting portion 820 described above except for the above-described difference.

[0373] Embodiments

[0374] Hereinafter, embodiments will be shown, and the present application will be specifically described. In addition, the present application is not limited to the following embodiments.

[0375] (Production of the current collector for the negative electrode)

[0376] (Manufacturing Example 1)

[0377] Six current collectors for the negative electrode were produced by the following process. First, as a support layer of the current collector for the negative electrode, a PET film (manufactured by Toray Industries, Inc., Lumirror #19-F60, thickness 6 μm) was prepared. Next, a Ni layer having a thickness of about 0.1 μm was formed on both surfaces of the PET film by electroless plating. Next, a copper layer having a thickness of 0.5 μm was formed on the Ni layer on each surface of the PET film by electroplating.

[0378] Next, a plurality of through holes were formed in a portion of the PET film. Thus, a through hole belt was formed. The cross-sectional shape of each through hole was circular, and the average diameter of each through hole was 30 μm. In addition, the pitch of the through holes was 80 μm.

[0379] Next, a copper layer was formed on the inner wall of the through hole by the same process as the process of producing the copper layer on the surface of the PET film. The thickness of the copper layer was 0.5 μm. The average diameter of the space of the through hole after the formation of the copper layer was 29 μm.

[0380] Thereafter, the PET film on which the through hole belt and the copper layer in the through hole were formed was cut to produce six current collectors. The above-described PET film was cut in such a manner that each current collector had a planar shape of an L letter shape having a rectangular current collecting portion of 38 mm x 50 mm and a rectangular tab portion of 10 mm x 5 mm. In each current collector, the above-described PET film was cut in such a manner that the short side of the tab portion was in contact with one of the short sides of the current collecting portion. In each current collector, the above-described PET film was cut in such a manner that one of the other long sides of the tab portion and one of the long sides of the current collecting portion were disposed on the same straight line.

[0381] The positive electrode connecting portion 820 described above is the same as the positive electrode connecting portion 820 described above except for the above-described difference. Figure 12The PET film was cut in a manner such that a through-hole band formed in the PET film was included in the tab portion, as described above. The TL of the tab portion of each current collector was 10 mm, and the TW was 5 mm, as described above. The through-hole band was formed in the tab portion of each current collector, and the HL of each current collector was 2 mm, and the HW was 5 mm. The distance from the edge of the tab portion, which was in contact with the current collecting portion, to the through-hole band was 6 mm. The distance from the edge of the tab portion, which was on the opposite side of the edge in contact with the current collecting portion, to the through-hole band was 2 mm.

[0382] Thus, six negative electrode current collectors were obtained. Table 1 shows the specifications of the negative electrode.

[0383] (Production Example 2)

[0384] Six negative electrode current collectors were produced by the same process as Production Example 1, except that a single through-hole having a diameter of 500 μm was formed instead of the through-hole band composed of a plurality of through-holes. Table 1 shows the specifications of the negative electrode.

[0385] (Production Example 3)

[0386] Six negative electrode current collectors were produced by the same process as Production Example 1, except that a polyimide film (manufactured by Du Pont-Teijin, Kapton, thickness 6 μm) was used as the support layer of the negative electrode current collector. Table 1 shows the specifications of the negative electrode.

[0387] (Production Example 4)

[0388] Six negative electrode current collectors were produced by the same process as Production Example 2, except that a polyimide film (manufactured by Du Pont-Teijin, Kapton, thickness 6 μm) was used as the support layer of the negative electrode current collector. Table 1 shows the specifications of the negative electrode.

[0389] (Production Example 5)

[0390] First, a Cu foil (manufactured by AS ONE Corporation, type 3-2349-01, thickness 10 μm) was prepared as the support layer of the negative electrode current collector. Next, the Cu foil was cut by the same process as Production Example 1, and six current collectors were produced. Table 1 shows the specifications of the negative electrode.

[0391] [Table 1]

[0392]

[0393] (Example 1)

[0394] (Production of Lithium Ion Secondary Battery)

[0395] First, as the negative electrode current collector, six current collectors obtained by Production Example 1 were prepared. As the positive electrode current collector, five Al foils (manufactured by MTI Corporation, BCAF-15U180, size 34 mm x 46 mm, thickness 15 μm) were prepared. The planar shape of the Al foils was an L shape having a rectangular current collecting portion of 34 mm x 46 mm and a rectangular tab portion of 10 mm x 5 mm.

[0396] As the negative electrode active material, a 38 mm x 50 mm Li metal foil (manufactured by Hitojyo Metal Co., Ltd., rolled lithium foil, thickness 20 μm) was prepared. As the positive electrode active material, NCM811 (manufactured by Nitobo Chemical Co., Ltd.) was prepared. As the separator, ten SW316F (manufactured by Shenzhen Starry New Material Co., Ltd., thickness 10 μm) were prepared. The planar shape of the separator was a rectangle of 42 mm x 54 mm.

[0397] Next, NCM811, Denka Black (manufactured by Denka Co., Ltd.), and PVDF (manufactured by Wintech Co., Ltd. #1100) were added to N-methylpyrrolidone (manufactured by Mitsubishi Chemical Corporation) to prepare a slurry of the positive electrode active material. The mass ratio of NCM811, Denka Black, and PVDF was 94:3:3. The above slurry was applied to the entire surface of the Al foil. The above slurry was applied to both surfaces of the Al foil. Thereafter, by drying the slurry, a positive electrode in which a positive electrode active material layer was formed on both surfaces of the Al foil was obtained. The thickness of the positive electrode active material layer after drying was 50 μm per surface. Thus, five positive electrodes were obtained. The thickness of each positive electrode was 115 μm.

[0398] Next, the above Li metal foil was attached to both surfaces of the current collector obtained by Production Example 1. Thus, six negative electrodes were obtained.

[0399] Next, an electrolyte (manufactured by KISHIDA Chemical Co., Ltd., LBG-00062) was prepared. In the above electrolyte, the solvent was a mixed solvent of ethylene carbonate and ethyl methyl carbonate, and the volume ratio of ethylene carbonate and ethyl methyl carbonate was 1:3. In the above electrolyte, the concentration of LiPF6 as the electrolyte was 1 mol / L.

[0400] Next, the negative electrode, the separator, the positive electrode, the separator, the negative electrode, the separator, the positive electrode, the separator, the negative electrode, the separator, the positive electrode, the separator, the negative electrode, the separator, the positive electrode, the separator, the negative electrode, the separator, the positive electrode, the separator, and the negative electrode were sequentially stacked to produce a battery structure. In addition, a Cu plate (manufactured by Nets Corporation, thickness: 100 μm) coated with a Ni layer having a thickness of 0.1 μm was cut to produce a lead for the negative electrode. The lead had a rectangular shape with a length of 40 mm and a width of 15 mm. A Cu plate (manufactured by Nets Corporation, thickness: 30 μm) coated with a Ni layer having a thickness of 0.1 μm was cut to produce a sub-lead for the negative electrode. The sub-lead had a square shape with a side length of 15 mm. Also, an Al plate (manufactured by Nets Corporation, thickness: 100 μm) was cut to produce a lead for the positive electrode. The lead had a rectangular shape with a length of 40 mm and a width of 15 mm.

[0401] Next, the tab portions of the five positive electrodes that were stacked were integrated. Specifically, first, after the tab portions of the five positive electrodes were stacked, the lead for the positive electrode was disposed on the uppermost tab portion. Thus, a stack that was to be the object of welding in the welding process on the positive electrode side was produced. As described above, the current collector of the positive electrode was an Al foil, and the lead for the positive electrode was an Al plate.

[0402] As the welding device, a lithium ion battery stack foil welding device (manufactured by Nag System Corporation) having a welding head with a welding nugget diameter of 4 mm was used to weld the five Al foils and the one Al plate. Thus, the tab portions of the five positive electrodes were integrated.

[0403] Next, the tab portions of the six negative electrodes that were stacked were integrated. Specifically, first, after the tab portions of the six negative electrodes were stacked, the six tab portions that were stacked were sandwiched between the lead and the sub-lead for the negative electrode. Thus, a stack that was to be the object of welding in the welding process on the negative electrode side was produced.

[0404] A region of 4 mm x 4 mm on the inner side of the sub-lead was set as a softening region. The position of the softening region was set so that the approximate center of the softening region coincided with the approximate center of the tab portion. A region of 2 mm x 2 mm on the inner side of the sub-lead was set as a welding region. The position of the welding region was set so that the approximate center of the welding region coincided with the approximate center of the softening region.

[0405] The above-described object of welding (i.e., the stack of the sub-lead, the six tab portions, and the lead) was disposed in the work area of the welding device. As the welding device, a lithium ion battery stack foil welding device (manufactured by Nag System Corporation) having a welding head with a welding nugget diameter of 4 mm was used.

[0406] First, the softened region of the sub lead was pressed using the tip of the welding device, and a pressure of 1.8 kN was applied to the softened region of the sub lead. Next, the softened region was heated by supplying power to the heating portion of the welding device. The power supply conditions at the time of heating were a current of 1.5 kA, a voltage of 3 V, and an application time of 10 ms. After stopping the power supply to the heating portion, the welding portion of the welding device was supplied with power, and the welded region was welded. The length of the period from the stop of the power supply to the heating portion to the start of the power supply to the welding portion was set to 1 ms. The power supply conditions at the time of welding were a current of 2.5 kA, a voltage of 3.5 V, and an application time of 20 ms. Thus, the electrode structure was produced.

[0407] Next, a compression test of the welded portion of the negative electrode was performed using a heating platen press (PCH-100-DAH manufactured by LabNect Corporation) having a 80 mm square platen. The compression test was performed at room temperature. A pressure of 506.625 kPa was applied to the entire sub lead. The application time of the pressure was 20 seconds.

[0408] Next, after the electrode structure on which the compression test was completed and the above-described electrolyte solution were put inside an aluminum-made laminated packaging, the laminated packaging was sealed. Thus, a test battery was produced. The specifications of the test battery are shown in Table 2.

[0409] (Example 2)

[0410] Other than that a tensile test of the welded portion of the negative electrode was performed instead of a compression test of the welded portion, the test battery was produced by the same procedure as in Example 1. The specifications of the test battery are shown in Table 2.

[0411] A tensile test was performed using a tensile compression tester (Force Tester MCT-2150W manufactured by A&D Company, Ltd.) by the following procedure. First, the lead was set on one of the sample grips of the tensile compression tester, and the root of the tab portion was set near the other of the sample grips. Next, the lead and the root of the tab portion were pulled by 5 N / mm 2 of the tensile strength, and the tensile test was ended at the time when the displacement produced a 5% deformation from before the test.

[0412] (Example 3)

[0413] Other than that the current collector obtained by Production Example 2 was used as the negative electrode current collector, the test battery was produced by the same procedure as in Example 1. The specifications of the test battery are shown in Table 2.

[0414] (Example 4)

[0415] A test battery was produced by the same procedure as in Example 1, except that the current collector obtained by Production Example 3 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0416] (Comparative Example 1)

[0417] A test battery was produced by the same procedure as in Example 2, except that the current collector obtained by Production Example 3 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0418] (Comparative Example 2)

[0419] A test battery was produced by the same procedure as in Example 2, except that the current collector obtained by Production Example 4 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0420] (Comparative Example 3)

[0421] A test battery was produced by the same procedure as in Example 1, except that the current collector obtained by Production Example 4 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0422] (Comparative Example 4)

[0423] A test battery was produced by the same procedure as in Example 2, except that the current collector obtained by Production Example 4 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0424] (Reference Example 1)

[0425] A test battery was produced by the same procedure as in Example 1, except that the current collector obtained by Production Example 5 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0426] (Reference Example 2)

[0427] A test battery was produced by the same procedure as in Example 2, except that the current collector obtained by Production Example 5 was used as the negative electrode current collector. The specifications of the test battery are shown in Table 2.

[0428] (Reference Example 3)

[0429] A test battery was produced by the same procedure as in Example 1, except that the current collector obtained by Production Example 5 was used as the negative electrode current collector and the compression test was not performed at the welding site. The specifications of the test battery are shown in Table 2. The test battery of Reference Example 3 was used as a reference for the cycle test described later.

[0430] [Table 2]

[0431]

[0432] (Evaluation)

[0433] (Cycle performance)

[0434] The cycle characteristics of each of the test batteries were evaluated under conditions of 4.2 V - 2.4 V using the test batteries produced in each of Examples 1 to 4, Comparative Examples 1 to 4, and Reference Examples 1 to 3. Specifically, the charging capacity, the discharging capacity, and the voltage value at the time of charging and discharging were recorded by repeating charging and discharging under a constant current for 100 cycles. The charging time for each cycle was 10 hours, and the discharging time for each cycle was 2 hours. For the conditions at the time of charging, the temperature was 25°C, the current density was 1.53 mA / cm 2 , and the current value was 24 mA. For the conditions at the time of discharging, the temperature was 25°C, the current density was 7.67 mA / cm 2 , and the current value was 120 mA.

[0435] The results of the cycle test of each of the test batteries are shown in Table 2. In Table 2, represents that the test battery has a performance of 90% or more of the reference value of the capacity retention rate after 100 cycles of the test battery of Reference Example 3. represents that the test battery has a performance of 80% or more and less than 90% of the above-mentioned reference value. represents that the test battery has a performance of 70% or more and less than 80% of the above-mentioned reference value. represents that the test battery has a performance of less than 70% of the above-mentioned reference value.

[0436] (Observation of the welded portion of the negative electrode)

[0437] The welded portion of the negative electrode of the test battery produced in each of Examples 1 to 4, Comparative Examples 1 to 4, and Reference Examples 1 to 3 was observed, and the presence or absence of the above-mentioned concave-convex region was confirmed. The confirmation results are shown in Table 2.

[0438] The presence or absence of the concave-convex portion was confirmed according to the following procedure. First, a sample including the welded region of the negative electrode was cut out from the negative electrode of each of the test batteries. The size of each sample was 50 mm x 50 mm, and the welded region was provided at the approximate center portion of each sample.

[0439] Next, X-CT observations were performed on samples from each embodiment and each comparative example. A BRUKER X-ray microscope (SKYSCAN 1272CMOS EDITION) was used for the X-CT observations. The aforementioned wavy shape was observed in all embodiments. However, the aforementioned wavy shape was not observed in the samples of the comparative examples. Here, SEM observations were performed on the samples of each comparative example. First, the samples of each comparative example were cut using a section polishing machine (manufactured by Nippon Electronics Corporation, product number IB-09020CP). Each sample was cut to a section whose cut surface included approximately the central portion of the welded area. Next, the cut surface was observed using SEM.

[0440] Figure 22 The X-CT observation results of the welding position of the negative electrode produced in Example 2 are shown. Figure 22 This is an X-CT image taken by observing the sample from the lead side, with the depth of the observation plane appropriately adjusted. Specifically, it is an image taken by observing the sample at an angle with the lead side as the front, so that the lead is not visible except for the welded part. Figure 22 The roughly circular area near the center is the welding area. For example... Figure 22 As shown, according to this embodiment, multiple folds that are generally circular or generally polygonal are arranged in a concentric circle or concentric polygonal pattern. For example, in the observation area 2200, multiple folds are formed adjacent to the welding area.

[0441] Figure 23 Show Figure 22 The X-CT observation results of the cross-section of the observation area 2200 are shown. Figure 23 As shown, according to this embodiment, it can be seen that multiple wrinkles or wavy shapes are formed not only inside the observation area 2300 sandwiched by the lead and sub-lead, but also on the outside of the observation area 2300. Specifically, at least three peaks are observed on the outside of the observation area 2300.

[0442] Figure 24 Show Figure 23 The X-CT observation results for the observation area 2300 are shown. Figure 23 As shown, according to this embodiment, multiple folds or wavy shapes are formed inside the observation area 2300 sandwiched between the lead wire and the sub-lead wire.

[0443] Figure 25 The image shows an SEM image of the solder joint location of the negative electrode produced in Comparative Example 1. Figure 25 The cross-section of the adjacent region to the welded area is shown. For example... Figure 25As shown, according to the present comparative example, it was found that the resin material pressed out from the welding region caused the copper layer formed on both surfaces of the negative electrode current collector to be broken.

[0444] The present application has been described above using embodiments, but the technical scope of the present application is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above-described embodiments. The technical scope of the present application can include any of such changes or improvements within the technical scope of the present application, which is defined by the claims.

[0445] Note that the order of execution of each process of the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is not particularly specified as "before," "prior to," and the like, and can be implemented in any order, unless otherwise specified, as long as the output of the preceding process is not used in the subsequent process. With regard to the flow of actions in the claims, the specification, and the drawings, for convenience, "first," "next," and the like are used, but this does not mean that the processes must be implemented in this order.

[0446] Explanation of Reference Signs

[0447] 100: flying object; 110: battery; 112: battery core; 120: power control circuit; 130: motor; 140: propeller; 150: sensor; 160: control device; 212: positive electrode case; 214: negative electrode case; 216: sealant; 218: metal spring; 220: positive electrode; 222: positive electrode current collector; 224: positive electrode active material layer; 230: separator; 240: negative electrode; 242: negative electrode current collector; 244: negative electrode active material layer; 260: structure; 350: electrolyte; 400: current collector; 420: support layer; 422: first plane; 424: second plane; 426: side surface; 442: conductive layer; 444: conductive layer; 500: current collector; 522: through-hole; 546: conductive material; 600: current collector; 620: through-hole; 622: inner wall portion; 642: conductive layer; 760: laminated structure; 820: positive electrode connecting portion; 822: lead wire; 824: sub-lead wire; 840: negative electrode connecting portion; 842: lead wire; 844: sub-lead wire; 1102: current collector; 1104: current collector; 1120: welding device; 1130: welding head; 1132: position adjusting portion; 1134: heating portion; 1136: welding portion; 1140: power source for heating; 1150: power source for welding; 1160: controller; 1520: integrated region; 1522: substantially center; 1540: region; 1600: concavo-convex region; 1620: adjacent region; 1640: smooth region; 1900: concavo-convex region; 2020: complex region; 2022: solid; 2200: observation region; 2300: observation region

Claims

1. A laminated body, comprising multiple sheets of material stacked together. Each of the plurality of sheet materials has: The support layer comprises a thermoplastic resin material; and A first metal layer and a second metal layer are formed on both sides of the support layer. In a portion of the plurality of sheet materials, the plurality of first metal layers and the plurality of second metal layers contained in the plurality of sheet materials are integrally formed. Each of the plurality of first metal layers and the plurality of second metal layers includes uneven regions having a corrugated shape or a wrinkled, aggregated shape. The laminate has: The integrated region is the area where the plurality of first metal layers and the plurality of second metal layers are integrated by welding; and The smooth region is the region that exits from the end of the integrated region. The smooth region is defined as the area within which the absolute difference between the maximum and minimum thickness measurements at three locations is less than 5% of the average thickness measurement at those three locations. The uneven region is formed in an adjacent region disposed between the integrated region and the smooth region.

2. The laminated body according to claim 1, wherein, In the uneven region, each metal layer includes a plurality of peaks and at least one valley arranged along the in-plane direction of each metal layer.

3. The laminated body according to claim 1, wherein, The volume ratio of the resin contained in the integrated region to the volume ratio of the metal contained in the integrated region is 5-50%.

4. The laminated body according to claim 1, wherein, The volume of the voids contained in the integrated region is less than 10% of the volume of the metal contained in the integrated region.

5. The laminated body according to claim 1, wherein, The plurality of sheet materials have: The first sheet material is disposed on the outermost side of one of the plurality of sheets materials; and The second sheet material is disposed on the outermost side of the other side of the plurality of sheets materials. The laminated body also has: The first supporting member supports the first sheet material; as well as The second support member supports the second sheet material. The first support member and the second support member both contain metal. In the portion of the plurality of sheet materials, the first support member, the second support member, the plurality of first metal layers, and the plurality of second metal layers are integrated.

6. The laminate according to claim 1, wherein, Each of the plurality of sheet materials has a region near the integrated region in which a plurality of through holes are formed, penetrating each sheet material.

7. The laminated body according to claim 1, wherein, It also includes a conductive member that electrically connects the first metal layer and the second metal layer disposed on each of the plurality of sheet materials.

8. The laminated body according to claim 1, wherein, The maximum thickness of the adjacent region is 1.1 to 1.3 times the average of the measured thicknesses at the three locations of the smooth region.

9. The laminate according to claim 8, wherein, Each of the plurality of sheet materials has a region near the integrated region in which a plurality of through holes are formed, penetrating each sheet material. The volume ratio of the resin contained in the integrated region to the volume ratio of the metal contained in the integrated region is 5-50%.

10. The laminate according to claim 1, wherein, The shape of the concave and convex regions in the surface perpendicular to the stacking direction of the multiple sheet materials is concentric circles or concentric polygons.

11. The laminate according to claim 1, wherein, The number of peaks disposed in the concave-convex region is 6 or more.

12. An electrode structure comprising: First electrode and second electrode; Third electrode; as well as First diaphragm and second diaphragm, The first electrode, the first diaphragm, the third electrode, the second diaphragm, and the second electrode are stacked sequentially. The first electrode and the second electrode each have: Current collector; as well as An active material layer disposed on at least one side of the current collector, The current collector includes: A support layer comprising thermoplastic resin material; and The first metal layer and the second metal layer are formed on both sides of the support layer. Near the ends of the first electrode and the second electrode, (i) the first electrode and the second electrode are stacked, and (ii) the first metal layer and the second metal layer of the first electrode and the first metal layer and the second metal layer of the second electrode are integrated. The first metal layer and the second metal layer of the first electrode, and the first metal layer and the second metal layer of the second electrode, each include uneven regions with a corrugated shape or a wrinkled aggregate shape. The stacked first electrode and second electrode have: The integrated region is the area where the first metal layer and the second metal layer of the first electrode and the first metal layer and the second metal layer of the second electrode are integrated by welding; and The smooth region is the region that exits from the end of the integrated region. The smooth region is defined as the area within which the absolute difference between the maximum and minimum thickness measurements at three locations is less than 5% of the average thickness measurement at those three locations. The uneven region is formed in an adjacent region disposed between the integrated region and the smooth region.

13. The electrode structure according to claim 12, wherein, It also has: Fourth electrode; as well as The third diaphragm, The first electrode, the first diaphragm, the third electrode, the second diaphragm, the second electrode, the third diaphragm, and the fourth electrode are stacked sequentially. The first electrode, the second electrode, the third electrode, and the fourth electrode each have: The current collector; and The active material layer, Near the ends of the third electrode and the fourth electrode, (i) the third electrode and the fourth electrode are stacked, and (ii) the first metal layer and the second metal layer of the third electrode and the first metal layer and the second metal layer of the fourth electrode are integrated. The first and second metal layers of the third electrode and the first and second metal layers of the fourth electrode each include a second uneven region having a corrugated shape or a wrinkled aggregate shape. The stacked third electrode and the fourth electrode have: The second integrated region is the region where the first metal layer and the second metal layer of the third electrode and the first metal layer and the second metal layer of the fourth electrode are integrated by welding. and The second smooth region is the region that exits from the end of the second integrated region. The second smooth region is the area within which the absolute value of the difference between the maximum and minimum thickness measurements at three locations is less than 5% of the average thickness measurements at those three locations. The second uneven region is formed in a second adjacent region disposed between the second integrated region and the second smooth region.

14. A battery comprising: The electrode structure according to claim 12 or 13; and A housing for accommodating the electrode structure.

15. A flying object possessing: The battery of claim 14; and The propulsion generating device uses the electrical energy stored in the battery to generate propulsion.

Images