Laminate, electrode structure, battery, flight, method for producing laminate, and method for producing electrode structure

Abstract

Provided is a laminate provided with a plurality of laminated sheet materials. Each of the plurality of sheet materials has: a support layer containing a resin material; and a first metal layer and a second metal layer formed on both surfaces 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 included in the plurality of sheet materials are integrated. The resin material may be a thermoplastic resin material. The ratio of the volume of the resin contained in an integrated region, which is a region where the plurality of first metal layers and the plurality of second metal layers are integrated, to the volume of the metal contained in the integrated region may be 5-50%. The ratio of the volume of voids contained in an integrated region, which is a region where the plurality of first metal layers and the plurality of second metal layers are integrated, to the volume of metal contained in the integrated region may be 10% or more.

Description

Technical Field

[0001] The present invention relates to a laminate, an electrode structure, a battery, a flying object, a method for producing a laminate, and a method for producing an electrode structure. Background Art

[0002] Patent document 1 discloses a welding method for welding a semi-insulator having a chemically synthesized film to a metal conductor. Patent document 2 discloses a welding method for welding a first metal material and a second metal material of an electronic component in which a first metal material and a second metal material are overlapped on both sides of a resin insulating plate. Patent document 3 discloses a collector having conductive layers formed on both sides of a support layer, and a conductive material is filled in a through hole that penetrates the support layer and the conductive layer.

[0003] Prior art literature

[0004] Patent Literature

[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 of the invention

[0008] In a first aspect of the present invention, a laminate is provided. The laminate, for example, comprises a plurality of laminated sheet materials. In the laminate, for example, each of the plurality of sheet materials has a supporting layer containing a thermoplastic resin material. Each of the plurality of sheet materials has, for example, a first metal layer and a second metal layer formed on both sides of the supporting layer. In the laminate, for example, in a part 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 integrated. The resin material may also be a thermoplastic resin material.

[0009] In any of the above-mentioned laminates, the ratio of the volume of the resin contained in the region where the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., the integrated region, to the volume of the metal contained in the integrated region is 5 to 50%. In any of the above-mentioned laminates, the plurality of sheet materials may include a first sheet material disposed at the outermost side of one side of the plurality of sheet materials. It is also possible that any of the above-mentioned laminates further includes a first supporting member for supporting the conductivity of the first sheet material. In any of the above-mentioned laminates, the main component of the first supporting member may be different from the main component of the plurality of first metal layers and the main component of the plurality of second metal layers. In any of the above-mentioned laminates, the ratio of the volume of the resin material to the total value of the volume of the same type of metal as the main component of the plurality of first metal layers and the same type of metal as the main component of the plurality of second metal layers in the integrated region is 5 to 50%.

[0010] In any of the above-mentioned laminates, the ratio of the volume of voids contained in the region where the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., the integrated region, to the volume of metal contained in the integrated region may be 10% or less. In any of the above-mentioned laminates, the plurality of sheet materials may include: a first sheet material disposed at the outermost side of one side of the plurality of sheet materials; and a second sheet material disposed at the outermost side of the other side of the plurality of sheet materials. Any of the above-mentioned laminates may include: a conductive first support member supporting the first sheet material; and a conductive or non-conductive second support member supporting the second sheet material.

[0011] In any of the above-mentioned laminates, each of the plurality of sheet materials may have an area in which a plurality of through holes penetrating each sheet material are formed near the area where the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., the integrated area. Any of the above-mentioned laminates may also include a conductive layer disposed on the inner wall of at least a portion of the plurality of through holes. In any of the above-mentioned laminates, the conductive layer may have three or more layers with different main components. In any of the above-mentioned laminates, a thermoplastic resin material may be disposed inside at least a portion of the plurality of through holes. In any of the above-mentioned laminates, the equivalent circle diameter of the plurality of through holes may be 15 μm to 150 μm. In any of the above-mentioned laminates, the interval between two adjacent through holes among the plurality of through holes may be 30 μm to 250 μm.

[0012] According to any of the above-mentioned laminates, for example, in each of the plurality of sheet materials, (a) the ratio of the volume of the thermoplastic resin material contained in the region where the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., the integrated region, to the volume of the metal contained in the integrated region, i.e., the first ratio, is smaller than (b) the ratio of the volume of the thermoplastic resin material contained in the third sheet material contained in the plurality of sheet materials at a position more than 5 mm away from the end of the integrated region to the volume of the metal, i.e., the second ratio. In any of the above-mentioned laminates, the third sheet material may be the sheet material having the largest second ratio among the plurality of sheet materials. In any of the above-mentioned laminates, the value of the first ratio may be 0.1 to 0.7 times the value of the second ratio.

[0013] In a second embodiment of the present invention, an electrode structure is provided. The electrode structure, for example, comprises a first electrode and a second electrode. The electrode structure, for example, comprises a third electrode and a fourth electrode. The electrode structure, for example, comprises a first separator, a second separator and a third separator. In the electrode structure, for example, the first electrode, the first separator, the third electrode, the second separator, the second electrode, the third separator and the fourth electrode are stacked in sequence. In the electrode structure, the first electrode and the second electrode each have, for example, a current collector. In the electrode structure, the first electrode and the second electrode each have, for example, an active material layer disposed on at least one side of the current collector. In the electrode structure, the current collector, for example, comprises a supporting layer comprising a thermoplastic resin material. In the electrode structure, the current collector, for example, comprises a first metal layer and a second metal layer formed on both sides of the supporting layer. Alternatively, the resin material may comprise a thermoplastic resin material. According to the electrode structure described above, for example, near the ends of the first electrode and the second electrode, 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.

[0014] In any of the above-mentioned electrode structures, (a) the ratio of the volume of the thermoplastic resin material contained in the region where the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., the first ratio, to the volume of the metal contained in the integrated region, is smaller than (b) the ratio of the volume of the thermoplastic resin material at a position of the collector contained in the first electrode or the second electrode that is more than 5 mm away from the end of the integrated region, i.e., the second ratio, i.e., the ratio of the collector of the first electrode or the collector of the second electrode that has the larger ratio.

[0015] In a third aspect of the present invention, a battery is provided. The battery described above includes, for example, any of the electrode structures according to the second aspect described above. The battery described above includes, for example, a case that houses the electrode structure.

[0016] In a fourth aspect of the present invention, a flying object is provided. The flying object, for example, includes any battery according to the second aspect. The flying object, for example, includes a propulsion generating device that generates propulsion using electrical energy stored in the battery.

[0017] In a fifth aspect of the present invention, a method for producing a laminate is provided. The above method, for example, has a preparation stage, in which a welding object is prepared, and the welding object has a supporting layer containing a thermoplastic resin material and a first metal layer and a second metal layer formed on both sides of the supporting layer. The above method, for example, has a stacking stage of stacking a plurality of welding objects. The above method, for example, has a softening stage, in which energy is applied to a softening area arranged in a portion of the plurality of welding objects to soften the resin material in the softening area. The above method, for example, has a pressing stage, in which a welding area arranged in at least a portion of the softening area is pressed. The above method, for example, has a welding stage, in which a current and / or voltage is applied to the pressed welding area to weld the first metal layer and the second metal layer of the plurality of welding objects. In the above method, the first metal layer and the second metal layer of each of the plurality of welding objects are, for example, electrically connected. In the above method, at least a portion of the softening area of ​​each of the plurality of welding objects is, for example, formed with a plurality of through holes penetrating the supporting layer, the first metal layer and the second metal layer.

[0018] In any of the above methods, a conductive member electrically connecting the first metal layer and the second metal layer may be provided on the inner wall of at least a portion of the plurality of through holes. In any of the above methods, the conductive member may include a plurality of layers. In any of the above methods, the plurality of layers may be made of materials different from each other. In any of the above methods, a plurality of through holes penetrating the support layer, the first metal layer, and the second metal layer may be formed in the welding regions of the plurality of welding objects. In any of the above methods, a plurality of through holes penetrating the first metal layer and the second metal layer may be formed in the softening regions of the plurality of welding objects adjacent to the welding regions.

[0019] In any of the above methods, the pressing stage may include the following stage: applying pressure to the stacked plurality of welding objects so that the softened resin material flows into at least a portion of the through-holes. In any of the above methods, the pressing stage may include the following stage: bringing the first metal layer and the second metal layer of each of the plurality of welding objects close to a distance that allows welding. In any of the above methods, a conductive member that electrically connects the first metal layer and the second metal layer is disposed on the inner wall of at least a portion of the plurality of through-holes. In any of the above methods, the stage of applying pressure to the plurality of welding objects may include the following stage: applying pressure to the stacked plurality of welding objects so that the softened resin material breaks the conductive member disposed on the inner wall of at least a portion of the through-holes and flows into at least a portion of the through-holes.

[0020] In any of the above methods, the welding stage may include a stage of applying a current and / or a voltage to the welding area while further pressing the welding area pressed in the pressing stage. Any of the above methods may also include a supporting stage in which a plurality of softened areas or welding areas of welding objects are sandwiched using a conductive first supporting member and a conductive or non-conductive second supporting member. The supporting stage may also be performed before the softening stage or the pressing stage.

[0021] In the sixth aspect of the present invention, a method for producing an electrode structure is provided. The above method, for example, has a stage of preparing a first electrode and a second electrode. The above method, for example, has a stage of preparing a third electrode and a fourth electrode. The above method, for example, has a stage of preparing a first separator, a second separator, and a third separator. The above method, for example, has a stage of stacking the first electrode, the first separator, the third electrode, the second separator, the second electrode, the third separator, and the fourth electrode in sequence. The above method, for example, has a stage of welding a portion of the first electrode and the second electrode. In the above method, the first electrode and the second electrode each, for example, have a current collector. In the above method, the first electrode and the second electrode each, for example, have an active material layer disposed on at least one side of the current collector. In the above method, the current collector, for example, has a supporting layer containing a thermoplastic resin material. In the above method, the current collector, for example, has a first metal layer and a second metal layer formed on both sides of the supporting layer. In the above method, the first metal layer and the second metal layer are, for example, electrically connected. In the above method, a plurality of through holes penetrating the supporting layer, the first metal layer, and the second metal layer are formed in at least a portion of the softened region disposed in a portion of the current collector.

[0022] In the above method, the stage of welding a part of the first electrode and the second electrode includes, for example, a stage of stacking the collector of the first electrode and the collector of the second electrode. The stage of welding a part of the first electrode and the second electrode includes, for example, a softening stage, in which energy is applied to the softened area of ​​the collector to soften the resin material of the softened area. The stage of welding a part of the first electrode and the second electrode includes, for example, a pressing stage, in which at least a part of the welding area arranged in the softened area is pressed. The stage of welding a part of the first electrode and the second electrode includes, for example, a welding stage, in which a current and / or voltage is applied to the pressed welding area to weld the first metal layer and the second metal layer of the respective collectors of the first electrode and the second electrode.

[0023] In addition, the above summary of the invention does not list all the required features of the present invention. In addition, sub-combinations of these feature groups may also constitute inventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 An example of the system configuration of the flying object 100 is schematically shown.

[0025] Figure 2 An example of a battery cell 112 is schematically shown.

[0026] Figure 3 Another example of the battery cell 112 is schematically shown.

[0027] Figure 4 An example of the current collector 400 is schematically shown.

[0028] Figure 5 An example of the current collector 500 is schematically shown.

[0029] Figure 6 An example of the current collector 600 is schematically shown.

[0030] Figure 7 An example of a stacked structure 760 is schematically shown.

[0031] Figure 8 An example of the electrical connection relationship between electrodes of the stacked structure 760 is schematically shown.

[0032] Fig. 9 An example of a method for manufacturing the battery cell 112 is schematically shown.

[0033] Fig.10 An example of a method for producing the positive electrode 220 is schematically shown.

[0034] Fig.11 An example of a welding process using welding device 1120 is shown.

[0035] Fig.12 An example of a plurality of through holes 620 provided in the current collector 1102 is shown.

[0036] Fig.13 An example of a plurality of through holes 620 provided in the current collector 1102 is shown.

[0037] Fig.14 An example of a process for producing the stacked structure 760 is shown.

[0038] Fig.15 An example of a cross section of the integrated region of the positive electrode connecting portion 820 is schematically shown.

[0039] Fig.16 An example of a SEM image of a cross section of the integration region of Example 1 is shown. DETAILED DESCRIPTION

[0040] According to one embodiment (sometimes referred to as the present embodiment) illustrated in this specification, a laminate is produced by welding a portion of a plurality of stacked welding objects. Each of the plurality of welding objects includes: a support layer containing a resin material; and a first metal layer and a second metal layer formed on both sides of the support layer. The welding object may also be a sheet-like material (sometimes referred to as a sheet material). The welding object may also be a collector for an electrode of a battery.

[0041] The first metal layer and the second metal layer of each of the plurality of welding targets are electrically connected. Thus, the first metal layer and the second metal layer can be welded by, for example, resistance welding.

[0042] The type of the resin material is not particularly limited, but any thermoplastic resin material can be used as the resin material. The support layer may be substantially composed of a thermoplastic resin material, or the support layer may be a thermoplastic resin material.

[0043] By using a thermoplastic resin material as the main component of the support layer, for example, the safety of the battery when the laminate is used as an electrode of the battery is improved. More specifically, in the case of thermal runaway of the battery described above, the thermoplastic resin material is melted by the heat. As a result, thermal runaway can be suppressed.

[0044] In addition, the thermoplastic resin material softens as the temperature of the resin material rises, and the fluidity increases. Therefore, in the welding process of multiple welding objects, if pressure is applied to the heated welding objects, the resin material arranged between the first metal layer and the second metal layer is easy to move, and the first metal layer and the second metal layer are close to or in contact. In this state, by applying energy to the first metal layer and the second metal layer, the first metal layer and the second metal layer are integrated.

[0045] When welding the first metal layer and the second metal layer, if pressure is applied to the first metal layer and the second metal layer so that the first metal layer and the second metal layer are close to or in contact, the support layer disposed between the first metal layer and the second metal layer is pressed out around the welding part. As a result, the volume around the welding part expands, impairing the smoothness. As the number of stacked welding objects increases, the influence of the above-mentioned volume expansion also increases.

[0046] In contrast, according to an example of the present embodiment, the support layer includes a thermoplastic resin material, and a plurality of through holes penetrating the support layer, the first metal layer, and the second metal layer are formed in a portion of each of the plurality of welding objects. In addition, at least a portion of the region where the through holes are formed is welded. Thus, volume expansion around the welding portion is suppressed.

[0047] According to an example of the present embodiment, a plurality of welding objects are welded by the following process. First, energy is applied to a softened region disposed in a portion of the plurality of welding objects. As described above, the support layer of the welding object of the present embodiment mainly includes, for example, a thermoplastic resin material. 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.

[0048] Next, the welding area disposed in at least a part of the softened area of ​​the welding object is pressed. Thus, pressure is applied to the resin material of the supporting layer disposed between the first metal layer and the second metal layer. The resin material present inside the welding area softens and has appropriate fluidity. Therefore, if an appropriate amount of pressure is applied to the resin material of the supporting layer, the resin material moves inside the welding object.

[0049] As described above, a plurality of through holes penetrating the support layer, the first metal layer, and the second metal layer are formed in the welding region of the welding object of the present embodiment. Therefore, compared with the case where no through holes are formed in the welding region, the amount of the resin material causing the above-mentioned volume expansion is small. In addition, according to the present embodiment, the resin material existing in the welding region flows into the inside of the through holes existing in the periphery of the welding region. In addition, a part of the resin material existing in the welding region flows into the inside of the through holes formed by the first metal layer and the second metal layer existing in the welding region.

[0050] If the welding area of ​​the welding object is pressed and the first metal layer and the second metal layer are close to or in contact, a current and / or a voltage is applied to the welding area of ​​the welding object. Thus, the first metal layer and the second metal layer of each of the plurality of welding objects are welded. In addition, the first metal layer and the second metal layer of the adjacent welding objects are welded.

[0051] As described above, according to this embodiment, the amount of resin material pushed out from the welding area during welding is small. In addition, the resin material pushed out during welding flows into the inside of the through hole. Therefore, according to this embodiment, the above-mentioned volume expansion is significantly suppressed compared to the case where the through hole is not formed in the welding area.

[0052] As described above, the above-mentioned welding object is, for example, a collector for an electrode of a battery, and the method for producing the above-mentioned stacked body or the method for welding a plurality of stacked welding objects can be applied to the production of an electrode structure arranged inside the shell of a battery (particularly, a secondary battery). According to the present embodiment, a through hole is formed in a portion of the collector, and therefore, the apparent density of the collector becomes smaller. In addition, the density of the resin material may be smaller than the density of the metal material constituting the first metal layer and the second metal layer. Therefore, according to the present embodiment, the energy density per unit mass of the battery core [Wh / kg-battery core] and / or the capacity per unit mass of the active material [mAh / g-active material] can be increased compared to existing battery cores.

[0053] For example, in the past, aluminum foil, copper foil, etc. having a thickness of about 8 to 20 μm were used as current collectors. Therefore, in existing batteries, the mass of the current collectors of the positive and negative electrodes is 20 to 25% relative to the mass of the battery core. In contrast, according to the present embodiment, a portion of the current collector is formed of a material (typically, air or a resin material) having a lower density than that of the aluminum foil or copper foil. As a result, a battery core having excellent energy density per unit mass and / or capacity per unit mass of active material 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. In addition, the battery having the battery core according to the present embodiment is particularly suitable for use in flying objects because of its high energy density per unit mass.

[0054] As described above, according to this embodiment, for example, it is possible to realize a rechargeable battery that can improve the amount of energy per unit weight of the rechargeable battery, is lighter and can store more electricity. The rechargeable battery can be brought to the disaster site, for example, and can be used to supply energy to disaster victims. Therefore, the laminate, electrode structure, and battery involved in this embodiment and their manufacturing methods can contribute to the realization of Goal 7 "Sustainable energy for all" or Goal 13 "Specific measures for climate change" of the Sustainable Development Goals (SDGs).

[0055] Hereinafter, the present invention will be described by way of the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0056] In this specification, when a numerical range is expressed as "A to B", this expression means A or more and B or less. In addition, "substituted or unsubstituted" means "substituted by any substituent or not substituted by a substituent". There is no particular limitation on the type of the above-mentioned substituent unless otherwise mentioned in the specification. There is no particular limitation on the number of the above-mentioned substituent unless otherwise mentioned in the specification.

[0057] (Overview of Flying Object 100)

[0058] Figure 1 An example of a system configuration of the flying object 100 is schematically shown. In the present embodiment, the flying object 100 includes a battery 110, a power control circuit 120, one or more motors 130, one or more propellers 140, one or more sensors 150, and a control device 160. In the present embodiment, the battery 110 includes one or more battery cells 112.

[0059] In this embodiment, the flying object 100 flies using the electric energy stored in the storage battery 110. Examples of the flying object 100 include an airplane, an airship, a balloon, a hot air balloon, a helicopter, and a drone.

[0060] In this embodiment, the battery 110 receives electric energy from an external charging device (not shown) via the power control circuit 120 and stores the electric energy in one or more battery cells 112. The battery 110 supplies the electric energy stored in the one or more battery cells 112 to the motor 130 via the power control circuit 120.

[0061] In the present embodiment, the battery cell 112 stores electric energy (sometimes referred to as charging the battery cell 112 ). Also, the battery cell 112 releases the stored electric energy (sometimes referred to as discharging the battery cell 112 ). The battery cell 112 may be a secondary battery.

[0062] The battery cell 112 may also be an all-solid battery. The battery cell 112 may also be an all-solid secondary battery. An all-solid secondary battery is a secondary battery that does not substantially contain the above-mentioned electrolyte solution or gel electrolyte, and includes, for example, a pair of electrodes and a solid electrolyte layer disposed between the pair of electrodes.

[0063] The secondary battery substantially does not contain an electrolyte or a gel electrolyte. It refers not only to the case where the secondary battery does not contain an electrolyte or a gel electrolyte, but also to the case where the secondary battery contains a small amount of electrolyte or a gel electrolyte. This is because, even if the constituent materials of the secondary battery are dissolved in the solvent contained in the electrolyte or the gel electrolyte, if the amount of the solvent contained in the secondary battery is small, the influence of the constituent materials of the secondary battery dissolved in the solvent on the battery performance can be ignored.

[0064] In one embodiment, the battery cell 112 does not include at least one of: (i) an electrolyte solution including a supporting electrolyte salt and a solvent and (ii) a gel electrolyte including a supporting electrolyte salt, an organic polymer compound and an organic solvent. In other embodiments, the ratio of the mass [kg] of the electrolyte solution and the gel electrolyte to the mass [kg] of the organic compound used as an active material is less than 5%.

[0065] Examples of carrier ions of secondary batteries include lithium, sodium, potassium, magnesium, and calcium. Examples of secondary batteries include sodium ion secondary batteries, lithium ion secondary batteries, lithium metal secondary batteries, lithium air secondary batteries, lithium sulfur secondary batteries, and magnesium ion secondary batteries.

[0066] For example, as an active material for a secondary battery mounted on a vehicle, a material that can store a large amount of charge per unit volume is often selected. On the other hand, in this embodiment, the battery cell 112 is mounted on the flying object 100. Therefore, the active material used for the battery cell 112 is preferably a material that can store a large amount of charge per unit mass.

[0067] The mass energy density of the battery cell 112 is preferably 350 [Wh / kg-battery cell] or more, more preferably 400 [Wh / kg-battery cell] or more, more preferably 500 [Wh / kg-battery cell] or more, more preferably 600 [Wh / kg-battery cell] or more, and further preferably 700 [Wh / g-battery cell] or more. Thus, a battery cell particularly suitable for use as a power source for flying objects is obtained.

[0068] The volume energy density of the battery cell 112 may also be 300 [Wh / m 3 -Battery cell] and above and 1200[Wh / m 3 -battery cell] or less, or 400[Wh / m 3 -Battery cell] and above and 1000[Wh / m 3 -battery cell] or less. When the battery cell 112 is carried on the flying object 100 as part of the power source of the flying object 100, the volume energy density of the battery cell 112 may be 600 [Wh / m 3 -battery cell] or less, it can also be 800[Wh / m 3 -battery cell] or below.

[0069] The battery cell 112 may have a mass energy density within the above numerical range and a volume energy density within the above numerical range. Thus, the battery cell that is difficult to use as a power source for a vehicle can be used as a power source for an aircraft. The details of the battery cell 112 will be described later.

[0070] In this embodiment, the power control circuit 120 controls the input and output of power from the battery 110. The power control circuit 120 may control the input and output of power from the battery 110 based on a command from the control device 160. The power control circuit 120 includes, for example, a plurality of switching elements that operate based on a control signal from the control device 160.

[0071] In this embodiment, the motor 130 receives electric energy from the battery 110 via the power control circuit 120. The motor 130 rotates the propeller 140 using the electric energy received from the battery 110. Thus, the motor 130 can generate propulsion force for the flying object 100 using the electric energy stored in the battery core 112.

[0072] In the present embodiment, the sensor 150 measures various physical quantities related to the position and posture of the flying object 100. Examples of sensors for measuring various physical quantities related to the position and posture of the flying object 100 include a GPS signal receiver, an acceleration sensor, an angular acceleration sensor, a gyro sensor, etc. The sensor 150 may also measure various physical quantities related to the state of the battery 110. Examples of sensors for measuring various physical quantities related to the state of the battery 110 include a temperature sensor, a current sensor, a voltage sensor, etc.

[0073] In this embodiment, the control device 160 controls the flying object 100. The control device 160 may also control the input and output of the power of the battery 110 by controlling the power control circuit 120. For example, the control device 160 controls the output current, output voltage, input current, input voltage, etc. of the battery 110. Thus, the control device 160 can control the position and posture of the flying object 100. The control device 160 may also control the power control circuit 120 based on the output from the sensor 150, thereby controlling the position and posture of the flying object 100.

[0074] The battery 110 is an example of a secondary battery. The battery cell 112 is also an example of a secondary battery. The motor 130 is also an example of a propulsion force generating device. The secondary battery is also an example of a battery.

[0075] (Overview of the battery cell 112)

[0076] Figure 2 An example of the battery cell 112 is schematically shown. In this embodiment, the battery cell 112 is a coin-type all-solid secondary battery as an example to describe the details of the battery cell 112. However, it should be noted that the battery cell 112 is not limited to a coin-type all-solid secondary battery.

[0077] (Battery Cell)

[0078] 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 collector 222 and a positive electrode active material layer 224. In the present embodiment, the negative electrode 240 includes a negative electrode collector 242 and a negative electrode active material layer 244.

[0079] In this embodiment, the battery cell 112 includes a structure 260 having a positive electrode 220, a separator 230, and a negative electrode 240. Figure 2As shown, the positive electrode 220 , the separator 230 , and the negative electrode 240 are stacked in this order, and the separator 230 is disposed between the positive electrode 220 and the negative electrode 240 .

[0080] In this embodiment, the details of the battery cell 112 are described by taking as an example a case where the battery cell 112 does not substantially contain an electrolyte solution or a gel electrolyte. In addition, in this embodiment, the details of the battery cell 112 are described by taking as an example a case where the positive electrode current collector 222 has (i) a conductive layer containing a conductive material and (ii) a supporting layer supporting the conductive layer.

[0081] In the present embodiment, by assembling the positive electrode case 212 and the negative electrode case 214, 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 accommodated 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 the repulsive force of the metal spring 218.

[0082] The positive electrode case 212 and the negative electrode case 214 are made of a conductive material having a disk-shaped thin plate shape, for example. In this embodiment, the sealant 216 seals the gap formed between the positive electrode case 212 and the negative electrode case 214. The sealant 216 contains an insulating material. The sealant 216 insulates the positive electrode case 212 and the negative electrode case 214.

[0083] (positive electrode)

[0084] In the present embodiment, the positive electrode collector 222 holds the positive electrode active material layer 224. In the present embodiment, the positive electrode collector 222 has a resistance of 0.01mΩ to 1Ω. Thus, before and after pressure is applied to the conductive layer of the positive electrode collector 222 (the details of the conductive layer will be described later) in the manufacture of the positive electrode collector 222, the change in voltage measured by applying current to the conductive layer under specific measurement conditions is suppressed to less than 100mV, for example. The positive electrode collector 222 may have a resistance of 0.01mΩ to 333mΩ, or may have a resistance of 0.01mΩ to 100mΩ.

[0085] The density of the positive electrode current collector 222 is adjusted to, for example, 1.1 to 2.0 g / cm 3 Thus, for example, the main component of the active material contained in the positive electrode active material layer 224 is anthraquinone (density: 1.3 g / cm 3 ), anthracene (density: 1.25g / cm 3 ) and / or naphthalene (density: 1.14 g / cm 3), the mass of the positive electrode 220 including the positive electrode collector 222 and the positive electrode active material layer 224 is very light, and the mass energy density of the battery cell 112 becomes large.

[0086] In this embodiment, at least a portion of the positive electrode current collector 222 is formed of a material having a lower density than metal. At least a portion of the positive electrode current collector 222 may also be formed of a material having a lower density than aluminum. For example, at least a portion of the positive electrode current collector 222 is formed of a resin. Thus, the battery core 112 can be made lighter.

[0087] In particular, when using a separator 230 whose main component is a solid electrolyte, the mass of the separator 230 becomes relatively large depending on the type of the solid electrolyte. Even in such a case, since at least a portion of the positive electrode current collector 222 is formed of a resin, an increase in the overall mass of the battery cell 112 is suppressed. As a result, the capacity per unit mass of the battery cell 112 and the energy density of the battery cell 112 are improved.

[0088] For example, the positive electrode current collector 222 includes: a conductive layer containing a conductive material; and a support layer supporting the conductive layer. The conductive layer and the support layer will be described in detail later.

[0089] Examples of the shape of the positive electrode current collector 222 include a foil shape (sometimes referred to as a plate shape, a film shape, a sheet shape, etc.), a mesh shape, a porous plate shape, etc. 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 may be 6 to 20 μm, or 4 to 10 μm.

[0090] 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 may be 1 to 100 μm or 5 to 50 μm per single surface of the positive electrode current collector 222.

[0091] The positive electrode active material layer 224 includes, for example, a positive electrode active material and a binding material (sometimes referred to as a binder). The positive electrode active material layer 224 may also include at least one of a conductive material and an ion conductive material. The positive electrode active material layer 224 may also include a positive electrode active material and an ion conductive material. Thus, the ion conductive path and / or the electron conductive path formed inside the positive electrode active material layer 224 may be prevented from being cut off.

[0092] In one embodiment, the positive electrode active material layer 224 is formed by applying a slurry containing a material constituting the positive electrode active material layer 224 and a solvent on at least one side of the positive electrode collector 222 and drying the slurry. As the above-mentioned solvent, various solvent substances or mixtures thereof are exemplified. The type of the above-mentioned solvent substance is not particularly limited, but as the above-mentioned solvent substance, N-methylpyrrolidone (NMP), water, etc. are exemplified.

[0093] In other embodiments, the positive electrode active material layer 224 is formed by mixing materials constituting the positive electrode active material layer 224, molding the mixture into a sheet, and pressing the sheet-shaped mixture onto at least one side of the positive electrode collector 222. When an organic compound is used as the positive electrode active material, the positive electrode collector 222 and the positive electrode active material layer 224 are pressed together in a manner that does not apply excessive pressure to the positive electrode active material layer 224 in the above-mentioned pressing step.

[0094] 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 above-mentioned coating gap can also be set to 200 μm or more. Thereby, the ion conduction path and / or the electron conduction path in the positive electrode active material layer 224 are prevented from being cut off.

[0095] When an organic compound is used as the positive electrode active material, the ratio of the volume of the organic compound that functions as the positive electrode active material to the volume of the positive electrode active material layer 224 (sometimes referred to as the active material volume ratio) may also be 60% or more. The ratio of the volume of the organic compound that functions as the positive electrode active material to the volume of the positive electrode active material layer 224 is preferably 60 to 80%, and more preferably 65 to 75%.

[0096] If the positive electrode active material layer 224 is pressed by high pressure, the volume of the organic compound that functions as the positive electrode active material relative to the volume of the positive electrode active material layer 224 exceeds 80%. If the above ratio exceeds 80%, the ion conduction path becomes thinner, or the ion conduction path is cut off. As a result, the capacity of the positive electrode active material layer 224 becomes smaller. The above high pressure may also refer to 50MPa or more, 100MPa or more, or 500MPa or more.

[0097] On the other hand, if the volume ratio of the organic compound functioning as the positive electrode active material to the volume of the positive electrode active material layer 224 is less than 60%, the conductivity of the carrier ions becomes good, but the density of the positive electrode active material becomes small, or the mass of the positive electrode active material contained in the positive electrode active material layer 224 becomes small. As a result, the capacity of the positive electrode active material layer 224 becomes small.

[0098] The ratio of the volume of the organic compound that functions as the positive electrode active material to the volume of the positive electrode active material layer 224 is determined, for example, based on the observation results using a three-dimensional SEM (Scanning Electron Microscopy). For example, according to the "Numerical Evaluation of the Volume of Active Materials Based on Three-Dimensional SEM (C0316)" (https: / / www.mst.or.jp / casestudy / tabid / 1318 / pdid / 87 / Default.aspx) proposed by the General Foundation for Materials Science and Technology Promotion, by repeatedly observing with SEM and obtaining dozens of continuous images, information such as the existence ratio and average volume of each substance in a constant volume can be obtained.

[0099] The volume ratio of the active material in the positive electrode active material layer 224 is determined, for example, by the magnitude of the pressure applied to the positive electrode active material layer 224 during the manufacturing process of the battery cell 112. If the pressure applied to the positive electrode active material layer 224 during the manufacturing process of the battery cell 112 increases, the volume ratio of the active material in the positive electrode active material layer 224 increases. The relationship between the magnitude of the pressure applied to the positive electrode active material layer 224 and the degree of increase in the volume ratio of the active material in the positive electrode active material layer 224 varies, for example, depending on the type of organic active material.

[0100] Therefore, for example, when an organic compound is used as the positive electrode active material, the maximum value of the pressure applied to the positive electrode active material layer 224 during the manufacturing process of the battery cell 112 is adjusted or managed so that the volume ratio of the active material in the positive electrode active material layer 224 contained in the manufactured battery cell 112 is 80% or less. This prevents the occurrence of a phenomenon in which the actual capacity of the positive electrode and / or the battery is significantly reduced compared to the theoretical capacity of the positive electrode and / or the battery.

[0101] In addition, the smaller the Young's modulus of the positive electrode active material layer 224, the greater the increase in the volume ratio of the active material when a high pressure is applied to the positive electrode active material layer 224. Therefore, when the positive electrode active material is an organic compound, the Young's modulus of the positive electrode active material layer 224 can also be adjusted to the same degree as the Young's modulus of the separator 230. For example, when the separator 230 is mainly composed of a polymer solid electrolyte and the positive electrode active material is an organic compound, the material and / or manufacturing conditions of the positive electrode active material layer 224 are determined in such a way that the ratio of the Young's modulus of the polymer solid electrolyte to the Young's modulus of the positive electrode active material is 0.7 to 1.3.

[0102] The Young's modulus is measured, for example, by a bending test specified in JIS K 7171. In the bending test, the deformation rate is set to about 1% / min.

[0103] The Young's modulus of the positive electrode active material layer 224 is not particularly limited. For example, when the pressure applied to the positive electrode active material layer 224 during the manufacturing process of the battery cell 112 is relatively small, the material of the positive electrode active material layer 224 can be arbitrarily determined without considering the Young's modulus of the positive electrode active material layer 224 .

[0104] In addition, according to the present embodiment, in the fixing process of the positive electrode collector 222 and the positive electrode active material layer 224, the pressure applied to the positive electrode collector 222 and the positive electrode active material layer 224 is also set or adjusted as described above. Thus, even if the conductive layer contained in the positive electrode collector 222 is thin, the breakage of the conductive layer is suppressed. As a result, the increase in the resistance of the positive electrode collector 222 is suppressed. According to the present embodiment, not only the reduction in capacity associated with the reduction in the ion conduction path and / or the conductive path of the positive electrode active material layer 224 can be suppressed, but also the reduction in capacity associated with the increase in the resistance of the positive electrode collector 222 can be suppressed.

[0105] As described above, according to the present embodiment, the pressure in the fixing process is set or adjusted so that the volume ratio of the organic compound functioning as the positive electrode active material to the volume of the positive electrode active material layer 224 is 60 to 80%. In this case, the volume ratio of the voids to the volume of the positive electrode active material layer 224 (sometimes referred to as void ratio, porosity, etc.) is 25 to 40%.

[0106] (Positive electrode active material)

[0107] As the positive electrode active material contained in the positive electrode active material layer 224, various materials that can absorb and release carrier ions of the battery core 112 are used. In this embodiment, the positive electrode active material is mainly composed of a single or multiple types of organic compounds. The positive electrode active material may also contain an inorganic compound. For example, more than 80% by mass of the positive electrode active material contained in the positive electrode active material layer 224 is composed of an organic compound.

[0108] As described above, the positive electrode 220 includes the positive electrode current collector 222 and the positive electrode active material layer 224. The mass of the positive electrode active material layer 224 may be 80% or more of the total mass of the positive electrode 220. The mass of the positive electrode active material may be 80% or more of the total mass of the positive electrode active material layer 224. The mass of the organic compound used as the positive electrode active material may be 80% or more of the total mass of the positive electrode active material.

[0109] Examples of the inorganic compound used as the positive electrode active material (sometimes referred to as inorganic positive electrode active material) include metal oxides, metal silicates, metal phosphates, metal borates, etc. Examples of the above-mentioned metals include transition metals such as V, Mn, Ni, and Co.

[0110] As the organic compound used as the positive electrode active material (sometimes referred to as the organic positive electrode active material), various redox active compounds are used as the organic positive electrode active material. As the organic positive electrode active material, conjugated polymers, disulfides, quinones, localized free radicals, non-localized free radicals, etc. are exemplified.

[0111] The organic positive electrode active material may also be at least one compound selected from the group consisting of aromatic hydrocarbons, aromatic heterocyclic compounds, olefins substituted with one or more cyano groups, disulfides and derivatives thereof, and compounds containing structures or structural units derived therefrom. In the case where the organic positive electrode active material is a compound containing the above-mentioned structural unit, its degree of polymerization may also be less than 100. The above-mentioned derivatives may also be compounds in which one or more hydrogens are substituted by keto groups, OH groups, OM groups (M is a metal. As M, examples include carrier metals, alkali metals, alkaline earth metals, etc. of the battery), nitro groups, etc.

[0112] The organic positive electrode active material may also be a compound containing a structure in which at least two oxygen atoms are bonded to a benzene ring, a compound containing a structure in which at least two carbon atoms of a benzene ring are substituted by nitrogen atoms, a compound containing a structure in which at least two cyano groups are bonded to a double bond of carbon, a compound containing a disulfide bond and its derivatives, and at least one compound selected from a group consisting of compounds containing structures or structural units derived therefrom. In the case where the organic positive electrode active material is a compound containing the above-mentioned structural units, its degree of polymerization may also be less than 100. The above-mentioned derivatives may also be compounds in which one or more hydrogens are replaced by keto groups, OH groups, OM groups (M is a metal. As M, carrier metals, alkali metals, alkaline earth metals, etc. of the battery are exemplified), nitro groups, etc.

[0113] The compound containing a structure derived from a specific compound may also be a compound containing a group or structure formed by removing at least one hydrogen contained in the specific compound. The compound containing a structure derived from a specific compound may be a monomer of the compound, or may be a dimer or a polymer. For example, as a compound containing a structure derived from benzoquinones, which is an example of a derivative of an aromatic hydrocarbon, derivatives of polycyclic aromatic hydrocarbons such as naphthoquinones, anthraquinones, and phenanthrenequinones are exemplified.

[0114] For example, 1,4-naphthoquinones, 5,8-dihydroxy-1,4-naphthoquinones, and 9,10-anthraquinone include structures derived from benzoquinones. 5,8-dihydroxy-1,4-naphthoquinones (sometimes referred to as naphthoxy) are also examples of compounds including structures derived from 1,4-naphthoquinones. In addition, 9,10-anthraquinone is also an example of a compound including a structure derived from 1,4-naphthoquinones.

[0115] Similarly, the compound containing the structural unit derived from the specific compound exemplifies a polymer or oligomer containing the specific compound, or a group or structure formed by removing at least one hydrogen contained in the specific compound as a repeating unit. As described above, the compound containing the structural unit derived from the specific compound is preferably an oligomer having a polymerization degree of less than 100. Thus, a battery with a large mass energy density can be produced.

[0116] The organic positive electrode active material may also be a compound such that when the volume ratio of the active material in the positive electrode active material layer 224 exceeds 80%, the capacity of the positive electrode active material layer 224 is less than 50% of the theoretical capacity of the positive electrode active material layer 224. The organic positive electrode active material may also be a compound such that when the volume ratio of the active material in the positive electrode active material layer 224 exceeds 80%, the capacity of the positive electrode active material layer 224 is less than 50% of the theoretical capacity of the positive electrode active material layer 224, and when the volume ratio of the active material in the positive electrode active material layer 224 is 65 to 75%, the capacity of the positive electrode active material layer 224 is more than 50% (more preferably more than 70%) of the theoretical capacity of the positive electrode active material layer 224. As described above, according to the present embodiment, when such an organic compound is used as a positive electrode active material of a battery, a high-capacity battery can also be produced.

[0117] As such an organic compound, an organic molecule having a relatively small molecular weight and having multiple electron donating and accepting capabilities is exemplified. When the above-mentioned organic molecule is a low molecular weight compound, the molecular weight of the organic molecule is, for example, 500 or less. The molecular weight of the above-mentioned organic molecule may also be 200 or less. When the above-mentioned organic molecule is a polymer or an oligomer, the molecular weight of the organic molecule is, for example, 5000 or less. The molecular weight of the above-mentioned organic molecule may also be 3000 or less.

[0118] The organic positive electrode active material may also be at least one compound selected from the group consisting of an organic compound having a solubility of 0.01 to 40 [mmol / l-EC] in ethylene carbonate (EC) at 0.1013 MPa and 25°C and an organic compound having a solubility of 0.01 to 40 [mmol / l-DEC] in diethyl carbonate (DEC) at 0.1013 MPa and 25°C. The upper limit of the numerical range associated with the above solubility is preferably 10 [mmol / l-solvent]. As described above, according to this embodiment, when such an organic compound is used as a positive electrode active material of a battery, a battery with a relatively long life can also be produced.

[0119] As such an organic compound, an organic molecule having a relatively small molecular weight and having multiple electron donating and accepting capabilities is exemplified. When the above-mentioned organic molecule is a low molecular weight compound, the molecular weight of the organic molecule is, for example, 500 or less. The molecular weight of the above-mentioned organic molecule may also be 200 or less. When the above-mentioned organic molecule is a polymer or an oligomer, the molecular weight of the organic molecule is, for example, 5000 or less. The molecular weight of the above-mentioned organic molecule may also be 3000 or less.

[0120] As described above, the easier it is for the organic active material of the battery cell 112 to dissolve in the solvent of the electrolyte or gel electrolyte, the greater the effect of the battery cell 112 not substantially containing the electrolyte or gel electrolyte. Ethylene carbonate (EC) and diethyl carbonate (DEC) are aprotic organic solvents widely used as solvents for electrolytes or gel electrolytes. Therefore, in the case where the positive electrode active material layer 224 contains an organic compound having the solubility described above, the effect of the battery cell 112 not substantially containing the electrolyte or gel electrolyte can be increased.

[0121] As a specific example of an organic positive electrode active material, at least one compound selected from a group consisting of compounds and derivatives thereof represented by the following chemical formulas, and compounds containing structures or structural units derived therefrom is exemplified. As described above, a compound containing a structure derived from a specific compound may also be a compound containing a group or structure formed by removing at least one hydrogen contained in the specific compound. Similarly, a compound containing a structural unit derived from a specific compound is exemplified: a polymer or oligomer containing the specific compound, or a group or structure formed by removing at least one hydrogen contained in the specific compound as a repeating unit.

[0122] [Chemical formula 1]

[0123]

[0124] The above derivatives may also be compounds in which one or more hydrogen atoms are replaced by deuterium, hydroxyl, OM group (M is a metal. Examples of M include carrier metals of batteries, alkali metals, alkaline earth metals, etc.), halogens, various organic groups, etc. The molecular weight of at least one compound selected from the above group is, for example, 500 or less. The molecular weight of at least one compound selected from the above group may also be 200 or less. The compound containing the above structural unit is preferably an oligomer having a degree of polymerization of 100 or less.

[0125] In the above chemical formula, R and R' independently represent hydrogen, deuterium, hydroxyl, OM group (M is a metal. As M, examples include carrier metals of batteries, alkali metals, alkaline earth metals, etc.), nitro, amino, sulfonic group or organic group. As the above organic group, various monovalent groups are exemplified. As the above organic group, alkyl, alkenyl, keto, carboxyl, carbonyl, aryl, cyano, groups containing heterocyclic rings, etc. are exemplified. It is also possible that R and R' independently represent one selected from hydrogen, deuterium, hydroxyl, OM group (M is a metal. As M, examples include carrier metals of batteries, alkali metals, alkaline earth metals, etc.), keto, cyano, carbonyl and groups containing heterocyclic rings.

[0126] The above-mentioned organic group may be a monovalent group having a structure derived from a compound represented by each of the following chemical formulas or a derivative thereof.

[0127] [Chemical formula 2]

[0128]

[0129] The monovalent group having a structure derived from the compound represented by the above chemical formula may also be a group formed by removing one of the hydrogen atoms bonded to the aromatic ring in each of the above chemical formulas. The derivative of the compound represented by the above chemical formula may also be a compound in which one or more hydrogen atoms in the above chemical formula are replaced by deutrium, halogen, hydroxyl, OM group (M is a metal. Examples of M include carrier metals of batteries, alkali metals, alkaline earth metals, etc.), nitro, amino, sulfonic group, organic group, etc. The monovalent group having a structure derived from the above derivative may also be a group formed by removing one of the hydrogen atoms bonded to the aromatic ring of the derivative.

[0130] For example, when the separator 230 is mainly composed of a solid electrolyte layer containing polyethylene oxide (PEO), poly (3,4-ethylenedioxythiophene) (PEDOT) and at least one compound selected from their derivatives, the positive electrode active material layer 224 contains at least one compound selected from the group consisting of compounds represented by the above chemical formulas and their derivatives, and compounds containing structures or structural units derived from them as an organic positive electrode active material. Thus, the reduction in the capacity of the above-mentioned organic positive electrode active material is suppressed.

[0131] The compounds and their derivatives respectively represented by the above chemical formulas have small molecular weights and multiple electron donation and acceptance capabilities. Therefore, by using them as active materials of the battery cell 112, the energy density and / or capacity of the battery cell 112 is improved. In particular, according to the present embodiment, the battery cell 112 does not substantially contain an electrolyte or a gel electrolyte. In addition, the positive electrode active material layer 224 has a porosity of more than 20%. As a result, the energy density and / or capacity of the battery cell 112 is further improved.

[0132] Examples of the compound containing a structure derived from p-benzoquinone in the above chemical formula include 5,8-dihydroxy-1,4-naphthoquinone (sometimes referred to as naphthylene), naphthylene dimer, etc. Similarly, examples of the compound containing a structure derived from hydroquinone include naphthylene, naphthylene dimer, etc. By using these compounds as positive electrode active materials, a battery with high energy density can be produced.

[0133] The compound containing a structure derived from p-benzoquinones may also be 2,4-dihydroxy-p-benzoquinones. In addition, as the compound containing a structure derived from o-benzoquinones in the above chemical formula, 4-nitro-1,2-benzoquinones and the like are exemplified. By using these compounds as positive electrode active materials, batteries with high energy density can be produced.

[0134] (Material other than positive electrode active material)

[0135] The binder contained in the positive electrode active material layer 224 binds the materials constituting the positive electrode active material layer 224 to maintain the electrode shape of the positive electrode 220. As the binder, for example, various polymer materials are used. Examples of the above-mentioned polymer materials include carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylic acid, polyethylene oxide (PEO), poly (3,4-ethylenedioxythiophene) (PEDOT) and their derivatives.

[0136] The binder may be a material that dissolves in a solvent whose solubility of the organic positive electrode active material is greater than a predetermined value. The solubility of the binder in the above-mentioned solvent may be greater than or equal to the solubility of the organic positive electrode active material in the above-mentioned solvent. Thus, for example, when the constituent materials of the battery cell 112 are reused, the disassembly process of the battery cell 112 becomes easier.

[0137] The conductive material contained in the positive electrode active material layer 224 improves the conductivity of the positive electrode active material layer 224. As a result, the resistance of the positive electrode 220 becomes smaller. The conductive material is not particularly limited as long as it is a material with electronic conductivity. Examples of the conductive material include carbon-based materials, metal-based materials, and conductive polymer materials. These conductive materials can also be used alone, or two or more conductive additives can be combined.

[0138] Examples of carbon-based materials include graphite, carbon black (e.g., acetylene black, Ketjen black, etc.), coke, amorphous carbon, carbon fiber, carbon nanotube, graphene, etc. Examples of metal-based materials include aluminum, gold, silver, copper, iron, platinum, chromium, tin, indium, titanium, nickel, etc. Examples of conductive polymer materials include polyphenylene derivatives, etc.

[0139] The conductive material may be a material that dissolves in a solvent whose solubility in the organic positive electrode active material is greater than a predetermined value. The solubility of the conductive material in the above-mentioned solvent may be greater than or equal to the solubility of the organic positive electrode active material in the above-mentioned solvent. Thus, for example, when the constituent materials of the battery cell 112 are reused, the decomposition process of the battery cell 112 becomes easy.

[0140] The conductive material contained in the positive electrode active material layer 224 improves 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, sulfide-based solid electrolytes, oxide-based solid electrolytes, polymer solid electrolytes, etc. are exemplified. As the conductive material, a polymer solid electrolyte can also be used. As the polymer solid electrolyte, at least one compound selected from polyethylene oxide (PEO), poly (3,4-ethylenedioxythiophene) (PEDOT) and their derivatives is exemplified.

[0141] As described later, in the present embodiment, the separator 230 includes a polymer solid electrolyte. The type of the polymer solid electrolyte used as the conductive material and the type of the polymer solid electrolyte included in the separator 230 may be the same or different.

[0142] The conductive material may be a material that dissolves in a solvent whose solubility of the organic positive electrode active material is greater than a predetermined value. The solubility of the conductive material in the above-mentioned solvent may be greater than or equal to the solubility of the organic positive electrode active material in the above-mentioned solvent. Thus, for example, when the constituent materials of the battery cell 112 are reused, the disassembly process of the battery cell 112 becomes easy.

[0143] (Diaphragm)

[0144] In this embodiment, the separator 230 is disposed between the positive electrode 220 and the negative electrode 240 to separate the positive electrode 220 and the negative electrode 240. The separator 230 ensures the conductivity of carrier ions 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.

[0145] In the present embodiment, the separator 230 includes a layered (sometimes referred to as a plate, sheet, or flake) solid electrolyte (sometimes referred to as a solid electrolyte layer). Thus, the solid electrolyte layer functions as a separator of the battery cell 112 .

[0146] In one embodiment, a solid electrolyte layer is used as the diaphragm 230. The solid electrolyte layer may also be composed of a single solid electrolyte layer or a plurality of solid electrolyte layers. In other embodiments, a laminate of one or more solid electrolyte layers and other layers containing materials other than the solid electrolyte is used as the diaphragm 230. The other layers may also have ion conductivity. As other layers, a composite material having a resin having a plurality of through holes and an ion conductive material filled in the through holes is exemplified.

[0147] Thus, a secondary battery that does not contain an electrolyte or a gel electrolyte can be produced. As a result, even if the positive electrode active material layer 224 and / or the negative electrode active material layer 244 contains an organic active material as the main active material, the reduction in battery life caused by the organic active material dissolving in the solvent of the electrolyte or the gel electrolyte can be suppressed.

[0148] In addition, the separator 230 is not limited to the above-mentioned embodiment. For example, a porous material in which a solid electrolyte is arranged inside the pores is used as the separator 230. Alternatively, the separator 230 may be made by solidifying the electrolyte arranged inside the supporting material or the retaining material after immersing an appropriate supporting material or retaining material in a gel electrolyte or an electrolyte solution and allowing the gel electrolyte or the electrolyte solution to penetrate into the supporting material or the retaining material. For example, the electrolyte arranged inside the supporting material or the retaining material is solidified by drying the supporting material or the retaining material containing the gel electrolyte or the electrolyte solution.

[0149] As the solvent of the electrolyte or gel electrolyte, ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), butylene carbonate (BC), fluoroethylene carbonate (FEC), γ-butyrolactone, cyclopentane, acetonitrile, 1,2-dimethoxymethane, 1,3-dimethoxypropane, diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and mixtures thereof are exemplified. In particular, ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) are widely used as solvents of the electrolyte or gel electrolyte.

[0150] (Solid electrolyte layer)

[0151] In the present embodiment, the separator 230 includes a solid electrolyte layer containing a polymer solid electrolyte as a main constituent material. The solid electrolyte layer contains, for example, 80% by mass or more of a true polymer solid electrolyte. When the separator 230 contains a polymer 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 high-pressure pressing process.

[0152] As a result, for example, even when the positive electrode active material layer 224 and / or the negative electrode active material layer 244 contains an organic active material, a positive electrode active material layer 224 and / or a negative electrode active material layer 244 having a porosity of 20% or more can be obtained. As described above, when the porosity of the positive electrode active material layer 224 and / or the negative electrode active material layer 244 is 20% or more, a battery cell 112 having a large ratio of the capacity of the positive electrode active material layer 224 and / or the negative electrode active material layer 244 to the theoretical capacity can be obtained. The ratio of the capacity of the positive electrode active material layer 224 and / or the negative electrode active material layer 244 to the theoretical capacity is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.

[0153] The solid electrolyte layer is prepared 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 above-mentioned solvent, various solvents or mixtures thereof are exemplified. The type of the above-mentioned solvent is not particularly limited, but as the above-mentioned solvent, N-methylpyrrolidone (NMP), water, methanol, etc. are exemplified.

[0154] As the polymer solid electrolyte constituting the solid electrolyte layer, for example, a -4 [S / cm] or higher. Alternatively, when an organic compound is used as the positive electrode active material and / or the negative electrode active material of the battery cell 112, at least one of the type, composition and molecular weight of the polymer material is determined in such a way that the ratio of the Young's modulus of the polymer material to the Young's modulus of the organic compound is 0.7 to 1.3.

[0155] This further suppresses the reduction in the porosity of the active material during the manufacturing process or use of the battery cell 112. In addition, when the solid electrolyte layer is mainly composed of a polymer solid electrolyte, the pressure inside the battery cell 112 during use of the battery cell 112 is usually about 0.1 to 0.2 [MPa]. On the other hand, when the solid electrolyte layer is mainly composed of an inorganic solid electrolyte, the pressure inside the battery cell during use of the battery cell is usually pressurized to about 500 [MPa].

[0156] As the polymer solid electrolyte constituting the solid electrolyte layer, at least one compound selected from polyethylene oxide (PEO), poly (3,4-ethylenedioxythiophene) (PEDOT) and their derivatives is exemplified. The solid electrolyte layer may be substantially composed of a single polymer solid electrolyte or may contain two or more polymer solid electrolytes.

[0157] (negative electrode)

[0158] In the present embodiment, the negative electrode current collector 242 holds the negative electrode active material layer 244. Examples of the material of the negative electrode current collector 242 include copper, aluminum, stainless steel, nickel, titanium, and alloys thereof.

[0159] The negative electrode current collector 242 may also include a conductive resin. The negative electrode current collector 242 may also be a conductive resin. In one embodiment, the conductive resin includes a conductive polymer. In other embodiments, the conductive resin may also be a polymer containing a conductive filler.

[0160] The negative electrode current collector 242 may also have the same structure as the positive electrode current collector 222. For example, the negative electrode current collector 242 includes a conductive layer containing a conductive material and a support layer supporting the conductive layer. The support layer is formed of a material with a lower density than metal. The support layer may also be formed of a material with a lower density than aluminum. For example, the support layer is formed of resin. In this way, the battery core 112 can be made lighter.

[0161] When a carrier metal is used as the negative electrode active material, the carrier metal may also serve as a current collector. For example, when the carrier metal of the battery cell 112 is lithium and the negative electrode active material is lithium metal, lithium metal is used as a current collector. In this case, the battery cell 112 may not include the negative electrode current collector 242.

[0162] Examples of the shape of the negative electrode current collector 242 include a foil shape (sometimes referred to as a plate shape, a film shape, etc.), a mesh shape, a porous plate shape, etc. The thickness of the negative electrode current collector 242 is not particularly limited, but may be 1 to 200 μm. The thickness of the negative electrode current collector 242 may also be 4 to 20 μm, or 6 to 10 μm.

[0163] In the present embodiment, the negative electrode active material layer 244 is formed on at least one surface of the negative electrode current collector 242. The thickness of the negative electrode active material layer 244 may be 0 to 200 μm or 1 to 100 μm per single surface of the negative electrode current collector 242.

[0164] The negative electrode active material layer 244 includes, for example, a negative electrode active material and a binding material (sometimes referred to as a binder). The negative electrode active material layer 244 may further include at least one of a conductive material and an ion conductive material. The negative electrode active material layer 244 may also include a negative electrode active material and an ion conductive material. Thus, the ion conductive path and / or the electron conductive path formed inside the negative electrode active material layer 244 may be prevented from being cut off.

[0165] In one embodiment, the negative electrode active material layer 244 is prepared by applying a slurry containing a material constituting the negative electrode active material layer 244 and an organic solvent on at least one side of the negative electrode current collector 242 and drying the slurry. As the above-mentioned solvent, various solvent substances or mixtures thereof are exemplified. The type of the above-mentioned solvent substance is not particularly limited, but as the above-mentioned solvent substance, N-methylpyrrolidone (NMP), water, etc. are exemplified.

[0166] In other embodiments, the negative electrode active material layer 244 is formed by mixing materials constituting the negative electrode active material layer 244, molding the mixture into a sheet, and pressing the sheet-shaped mixture onto at least one surface of the negative electrode collector 242. When an organic compound is used as the negative electrode active material, the negative electrode collector 242 and the negative electrode active material layer 244 are pressed together in a manner that does not apply excessive pressure to the negative electrode active material layer 244 in the above-mentioned pressing step.

[0167] For example, when the precursor material of the negative electrode active material layer 244 is coated on the negative electrode current collector 242 using a coater, the pressure applied to the precursor material of the negative electrode active material layer 244 is adjusted. For example, the coating gap of the coater is set to 180 μm or more. The above coating gap can also be set to 200 μm or more. Thus, the ion conduction path and / or the electron conduction path in the negative electrode active material layer 244 are prevented from being cut off.

[0168] When an organic compound is used as the negative electrode active material, the ratio of the volume of the organic compound that functions as the negative electrode active material to the volume of the negative electrode active material layer 244 (sometimes referred to as the active material volume ratio) may be 60% or more. The ratio of the volume of the organic compound that functions as the negative electrode active material to the volume of the negative electrode active material layer 244 is preferably 60 to 80%, and more preferably 65 to 75%.

[0169] If the negative electrode active material layer 244 is pressed by high pressure, the volume of the organic compound that functions as the negative electrode active material relative to the volume of the negative electrode active material layer 244 exceeds 80%. If the above ratio exceeds 80%, the ion conduction path becomes thinner, or the ion conduction path is cut off. As a result, the capacity of the negative electrode active material layer 244 becomes smaller. The above high pressure may also refer to 50 MPa or more, 100 MPa or more, or 500 MPa or more.

[0170] On the other hand, if the volume ratio of the organic compound functioning as the negative electrode active material to the volume of the negative electrode active material layer 244 is less than 60%, the conductivity of the carrier ions becomes good, but the density of the negative electrode active material becomes small, or the mass of the positive electrode active material contained in the negative electrode active material layer 244 becomes small. As a result, the capacity of the negative electrode active material layer 244 becomes small.

[0171] The volume ratio of the active material in the negative electrode active material layer 244 is derived by the same process as that of the positive electrode active material layer 224. For example, the volume ratio of the active material in the negative electrode active material layer 244 is determined based on observation results using three-dimensional SEM (Scanning Electron Microscopy).

[0172] The volume ratio of the active material in the negative electrode active material layer 244 is determined, for example, by the magnitude of the pressure applied to the negative electrode active material layer 244 during the manufacturing process of the battery cell 112. If the pressure applied to the negative electrode active material layer 244 during the manufacturing process of the battery cell 112 increases, the volume ratio of the active material in the negative electrode active material layer 244 increases. The relationship between the magnitude of the pressure applied to the negative electrode active material layer 244 and the degree of increase in the volume ratio of the active material in the negative electrode active material layer 244 varies, for example, depending on the type of organic active material.

[0173] Therefore, for example, when an organic compound is used as the negative electrode active material, the maximum value of the pressure applied to the negative electrode active material layer 244 during the manufacturing process of the battery cell 112 is adjusted or managed so that the volume ratio of the active material in the negative electrode active material layer 244 contained in the manufactured battery cell 112 is 80% or less. This prevents the occurrence of a phenomenon in which the actual capacity of the negative electrode and / or the battery is significantly reduced compared to the theoretical capacity of the negative electrode and / or the battery.

[0174] In addition, the smaller the Young's modulus of the negative electrode active material layer 244, the greater the increase in the volume ratio of the active material when a high voltage is applied to the negative electrode active material layer 244. Therefore, when the negative electrode active material is an organic compound, the Young's modulus of the negative electrode active material layer 244 can also be adjusted to the same degree as the Young's modulus of the separator 230. For example, when the separator 230 is mainly composed of a polymer solid electrolyte and the negative electrode active material is an organic compound, the material and / or manufacturing conditions of the negative electrode active material layer 244 are determined in such a way that the ratio of the Young's modulus of the polymer solid electrolyte to the Young's modulus of the negative electrode active material is 0.7 to 1.3.

[0175] The Young's modulus is measured, for example, by a bending test specified in JIS K 7171. In the bending test, the deformation rate is set to about 1% / min.

[0176] The Young's modulus of the negative electrode active material layer 244 is not particularly limited. For example, when the pressure applied to the negative electrode active material layer 244 during the manufacturing process of the battery cell 112 is relatively small, the material of the negative electrode active material layer 244 can be arbitrarily determined without considering the Young's modulus of the negative electrode active material layer 244 .

[0177] As described later, a foil of a carrier metal such as lithium metal may be used as the negative electrode active material layer. In this case, the material of the negative electrode active material layer can be determined without considering the Young's modulus of the negative electrode active material layer.

[0178] (Negative electrode active material)

[0179] As the negative electrode active material contained in the negative electrode active material layer 244, various materials that can absorb and release the carrier ions of the battery core 112 are used. The negative electrode active material can also be an inorganic compound or an organic compound. These negative electrode active materials can also be used alone, or two or more negative electrode active materials can be combined. For example, a metal foil that can release the carrier ions of the battery core 112 is used as the negative electrode active material layer 244. As a result, the mass energy density of the battery core 112 is improved.

[0180] In the case where the negative electrode current collector 242 has a conductive layer containing a conductive material and a supporting layer supporting the conductive layer in the same manner as the positive electrode current collector 222, according to one embodiment, a metal (for example, Li metal) capable of releasing carrier ions of the battery core 112 is used as the negative electrode active material. In this case, almost the entirety of the negative electrode active material contained in the negative electrode active material layer 244 is composed of the metal. In other embodiments, the negative electrode active material may also be mainly composed of a single or multiple types of organic compounds. The negative electrode active material may also contain an inorganic compound. For example, more than 80% by mass of the negative electrode active material contained in the negative electrode active material layer 244 is composed of an organic compound.

[0181] Examples of inorganic compounds used as negative electrode active materials (sometimes referred to as inorganic negative electrode active materials) include (i) carrier metals and alloys containing them, (ii) tin, silicon and alloys containing them, (iii) silicon oxide, and (iv) titanium oxide. For example, when the battery cell 112 is a lithium secondary battery, metallic lithium, lithium titanium oxide (LTO), etc. are used as negative electrode active materials. When a material that does not contain a carrier metal is used as a negative electrode active material, the material may be pre-doped with a carrier metal.

[0182] As an organic compound used as a negative electrode active material (sometimes referred to as an organic negative electrode active material), it may also be at least one compound selected from the group consisting of aromatic heterocyclic compounds and their derivatives, and compounds containing structures or structural units derived therefrom. In the case where the organic negative electrode active material is a compound containing the above-mentioned structural units, its degree of polymerization may also be less than 100. The above-mentioned derivatives may also be compounds in which one or more hydrogens are replaced by keto groups, OH groups, OM groups (M is a metal. As M, examples include carrier metals of batteries, alkali metals, alkaline earth metals, etc.), nitro groups, etc.

[0183] As described above, the negative electrode active material layer 244 may also include a foil-shaped carrier metal. For example, the negative electrode active material layer 244 includes a lithium metal foil. Thus, the carrier metal is supplied to the battery core 112. The thickness of the metal foil may also be 1 to 200 μm, 10 to 100 μm, or 20 to 50 μm. The thickness and / or mass of the metal foil may also be determined according to the content of the positive electrode active material in the positive electrode active material layer 224.

[0184] (Materials other than negative electrode active material)

[0185] The binder contained in the negative electrode active material layer 244 binds the materials constituting the negative electrode active material layer 244 to maintain the electrode shape of the negative electrode 240. As the binder, for example, various polymer materials are used. Examples of the above-mentioned polymer materials include carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylic acid, polyethylene oxide (PEO), poly (3,4-ethylenedioxythiophene) (PEDOT) and their derivatives.

[0186] The binder may be a material that dissolves in a solvent whose solubility in the organic negative electrode active material is greater than a predetermined value. The solubility of the binder in the above-mentioned solvent may be greater than or equal to the solubility of the organic negative electrode active material in the above-mentioned solvent. Thus, for example, when the constituent materials of the battery cell 112 are reused, the decomposition process of the battery cell 112 becomes easier.

[0187] The conductive material contained in the negative electrode active material layer 244 improves the conductivity of the negative electrode active material layer 244. As a result, the resistance of the negative electrode 240 becomes small. The conductive material is not particularly limited as long as it has electronic conductivity. Examples of the conductive material include carbon-based materials, metal-based materials, and conductive polymer materials. These conductive materials can also be used alone, or two or more conductive additives can be combined.

[0188] Examples of carbon-based materials include graphite, carbon black (e.g., acetylene black, Ketjen black, etc.), coke, amorphous carbon, carbon fiber, carbon nanotube, graphene, etc. Examples of metal-based materials include aluminum, gold, silver, copper, iron, platinum, chromium, tin, indium, titanium, nickel, etc. Examples of conductive polymer materials include polyphenylene derivatives, etc.

[0189] The conductive material may be a material that dissolves in a solvent whose solubility in the organic negative electrode active material is greater than a predetermined value. The solubility of the binder in the above-mentioned solvent may be greater than or equal to the solubility of the organic negative electrode active material in the above-mentioned solvent. Thus, for example, when the constituent materials of the battery cell 112 are reused, the decomposition process of the battery cell 112 becomes easier.

[0190] The conductive material contained in the negative electrode active material layer 244 improves the conductivity of the carrier ions in the negative electrode active material layer 244. As the conductive material, for example, various solid electrolytes are used. As the solid electrolyte, sulfide-based solid electrolytes, oxide-based solid electrolytes, polymer solid electrolytes, etc. are exemplified. As the conductive material, a polymer solid electrolyte can also be used. As the polymer solid electrolyte, at least one compound selected from polyethylene oxide (PEO), poly (3,4-ethylenedioxythiophene) (PEDOT) and their derivatives is exemplified.

[0191] As described above, in the present embodiment, the separator 230 includes a polymer solid electrolyte. The type of the polymer solid electrolyte used as the conductive material and the type of the polymer solid electrolyte included in the separator 230 may be the same or different.

[0192] The conductive material may be a material that dissolves in a solvent whose solubility of the organic negative electrode active material is greater than a predetermined value. The solubility of the conductive material in the above-mentioned solvent may be greater than or equal to the solubility of the organic negative electrode active material in the above-mentioned solvent. Thus, for example, when the constituent materials of the battery cell 112 are reused, the decomposition process of the battery cell 112 becomes easy.

[0193] The positive electrode case 212 may be an example of a case. The negative electrode case 214 may be an example of a case. The positive electrode 220 may be an example of an electrode. The positive electrode current collector 222 may be an example of a current collector. The positive electrode active material layer 224 may be an example of an active material layer. The negative electrode 240 may be an example of an electrode. The negative electrode current collector 242 may be an example of a current collector. The negative electrode active material layer 244 may be an example of an active material layer. The organic active material may be an example of an organic compound. The organic positive electrode active material may be an example of an organic compound. The organic negative electrode active material may be an example of an organic compound.

[0194] (An example of another embodiment)

[0195] In the present embodiment, the details of the battery core 112 are described by taking the case where the battery core 112 is a coin-type secondary battery as an example. However, the type and structure of the battery core 112 are not limited to the present embodiment. In other embodiments, the battery core 112 may also be a cylindrical battery having a wound electrode body in which a positive electrode, a separator, and a negative electrode are wound in a spiral shape. In yet another embodiment, the battery core 112 may also be a laminated battery in which a stacked electrode body in which positive electrodes and negative electrodes are alternately stacked with a separator is sealed by lamination. In yet another embodiment, the structure 260 may also have a plurality of stacked positive electrodes 220, and in a portion of the stacked positive electrodes 220, the positive electrode collectors 222 of the stacked positive electrodes 220 are integrated. In this case, the structure 260 may also be an example of a stacked body or an electrode structure. In another embodiment, the structure 260 may include a plurality of stacked negative electrodes 240, and the negative electrode current collectors 242 of the stacked negative electrodes 240 may be integrated in a portion of the stacked negative electrodes 240. In this case, the structure 260 may also be an example of a stacked body or an electrode structure.

[0196] In this embodiment, the details of the battery cell 112 are described by taking the case where the negative electrode 240 has a negative electrode collector 242 and a negative electrode active material layer 244 as an example. However, the negative electrode of the battery cell 112 is not limited to this embodiment. In other embodiments, a foil-shaped carrier metal functions as the negative electrode collector 242 and the negative electrode active material layer 244. For example, when the battery cell 112 is a lithium metal secondary battery, metallic lithium can be used as the negative electrode.

[0197] In this embodiment, the details of the battery cell 112 are described by taking as an example a case where the positive electrode current collector 222 has (i) a conductive layer containing a conductive material and (ii) a supporting layer supporting the conductive layer, the positive electrode active material layer 224 mainly contains an organic compound as an active material, and the negative electrode 240 has an arbitrary structure. However, the negative electrode of the battery cell 112 is not limited to this embodiment.

[0198] In other embodiments, the negative electrode current collector 242 may include (i) a conductive layer including a conductive material and (ii) a supporting layer supporting the conductive layer, the negative electrode active material layer 244 may mainly include an organic compound as an active material, and the positive electrode 220 may have any structure. In still another embodiment, the positive electrode current collector 222 and the negative electrode current collector 242 may include (i) a conductive layer including a conductive material and (ii) a supporting layer supporting the conductive layer, and the positive electrode active material layer 224 and the negative electrode active material layer 244 may mainly include an organic compound as an active material.

[0199] Figure 3 Another example of the battery cell 112 is schematically shown. Figure 3 The battery core 112 described above contains a liquid or gel electrolyte 350 in addition to the metal spring 218, the positive electrode 220, the separator 230 and the negative electrode 240 in the space formed by the positive electrode shell 212 and the negative electrode shell 214; and the separator 230 can be made of a material other than a solid electrolyte. Figure 2 The battery cell 112 shown is different. Figure 3 The battery cell 112 described above may have the following features in addition to the above differences: Figure 2 The battery cell 112 described above has the same structure.

[0200] As the liquid or gel electrolyte 350 , a known electrolytic solution or gel electrolyte can be used. As the separator 230 , a known separator can be used.

[0201] use Figure 4 , Figure 5 as well as Figure 6 , details of the positive electrode current collector 222 will be described. As described above, the negative electrode current collector 242 may also have the same structure as the positive electrode current collector 222. Figure 4 A cross-sectional view of a current collector 400 as an example of the positive electrode current collector 222 is schematically shown. Figure 5 An example of a cross-sectional view of a current collector 500 as an example of the positive electrode current collector 222 is schematically shown. Figure 6 An example of a cross-sectional view of a current collector 600 as an example of the positive electrode current collector 222 is schematically shown.

[0202] like Figure 4 As shown, the current collector 400 includes a support layer 420, a conductive layer 442, and a conductive layer 444. In this embodiment, the support layer 420 has a first plane 422, a second plane 424, and a side surface 426. In this 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.

[0203] In this embodiment, the supporting layer 420 supports the conductive layer 442 and the conductive layer 444. Thus, damage to the conductive layer 442 and the conductive layer 444 is suppressed. The density of the supporting layer 420 is lower than that of the conductive layer 442 or the conductive layer 444. For example, the supporting layer 420 is made of a material having a lower density than that of the conductive layer 442 or the conductive layer 444. The supporting layer 420 may also be a sheet-shaped resin material.

[0204] The resin material may be a thermoplastic resin or a thermosetting resin. The support layer 420 may be composed of a single type of resin material or may contain multiple types of resin materials. As described above, when a portion of the stacked multiple collectors 400 is welded, the resin material preferably mainly contains a thermoplastic resin or is substantially composed of a thermoplastic resin. Thus, for example, by heating the support layer before welding, the fluidity of the support layer is improved. In addition, in the case where the support layer 420 mainly contains a thermoplastic resin or the support layer 420 is substantially composed of a thermoplastic resin, compared with the case where the support layer 420 mainly contains a thermosetting resin or the support layer 420 is substantially composed of a thermosetting resin, the multiple collectors 400 are firmly welded. Thus, a laminate having excellent strength at the weld position and low resistance at the weld position can be produced.

[0205] The conductivity of the support layer 420 is not particularly limited, but the conductivity of the support layer 420 may be smaller than the conductivity 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 may be greater than the thickness of the conductive layer 442 or the conductive layer 444. If the thickness of the support layer 420 increases, the mass of the support layer 420 also increases. Therefore, when the support layer 420 is a sheet-shaped resin material, the thickness of the support layer 420 may also be 10 μm or less, preferably 7 μm or less, and more preferably 5 μm or less.

[0206] In this embodiment, the conductive layer 442 and the conductive layer 444 include a conductive material. The conductive material may have a resistivity of 8.0×10 -8 [Ω·m] or more. The conductive material may also be a metal. Examples of the above-mentioned metals include aluminum, stainless steel, nickel, or alloys thereof. Examples of stainless steel include SUS-430, SUS-304, etc. The conductive material may also be aluminum.

[0207] The thickness of the conductive layer 442 and / or the conductive layer 444 (shown in the figure as the length in the up-down direction) may also be 0.05 μm to 7 μm. The thickness of the conductive layer 442 and / or the conductive layer 444 may 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 may 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 more 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. Therefore, by providing the collector 400 with a conductive layer 442 and / or a conductive layer 444 having a thickness of less than 5 μm, the energy density per unit mass of the battery cell [Wh / kg-battery cell] is improved compared to the case where commercially available aluminum foil is used as the conductive layer 442 and / or the conductive layer 444.

[0208] At least one of the conductive layer 442 and / or the conductive layer 444 may also be a layered or foil-shaped aluminum having the above-mentioned thickness. The layered or foil-shaped aluminum may also be disposed on the surface of the support layer 420 by pasting, or may be formed on the surface of the support layer 420 by a vapor deposition method, a deposition method, or the like.

[0209] When 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 core 112 is improved. When 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 core 112 is further improved. When 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 core 112 is greatly improved. Generally, 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 damaged. However, the conductive layer 442 and the conductive layer 444 involved in this embodiment are supported by the support layer 420. Therefore, even when the thickness of the conductive layer 442 and / or the conductive layer 444 is about 0.05 to 0.1 μm, the damage of the conductive layer 442 and / or the conductive layer 444 can be suppressed.

[0210] In the case where the support layer 420 is a resin material, the resistance of the conductive layer 442 and the conductive layer 444 to fracture in the above-mentioned fixing process is the same as the resistance of the collector 400 to fracture in the above-mentioned fixing process. The degree of resistance of the collector 400 to fracture is determined, for example, by a tensile test of a sample cut out in a rectangular shape from the collector 400 in a state including the support layer 420, the conductive layer 442, and the conductive layer 444. In addition, when a part of the conductive layer 442 and the conductive layer 444 is broken in the fixing process, the resistance of the conductive layer 442 and the conductive layer 444 may be increased compared to before the fixing process is performed.

[0211] The size and shape of the sample are disclosed, for example, in "Testing Machine Academia" (Keyence Co., Ltd., [online] https: / / www.keyence.co.jp / ss / products / recorder / testing-machine / material / tension.jsp (April 6, 2022)), having an overall rectangular shape of 20 mm in width and 100 mm in length, and a tapered area of ​​40 mm in length in the center. The tapered area has a narrow width area of ​​10 mm in width and 20 mm in length in the center. The end of one side of the tapered area and the end of one side of the narrow width area are connected, and the end of the other side of the tapered area and the end of the other side of the narrow width area are connected.

[0212] The tensile test is performed, for example, according to IPC-TM-650 or in accordance with IPC-TM-650. Specifically, the tensile strength of the sample is measured by installing a fixing fixture at both ends of the sample and pulling the sample up and down. The tensile speed is set to, for example, 2 inches / min (50.8 mm / min). The tensile strength under the above conditions is sometimes expressed, for example, as Ts(50). The numerical value in the above brackets represents the tensile speed.

[0213] The tensile strength Ts(50) of the above-mentioned sample may be 360 ​​MPa or more. The tensile strength Ts(50) may be 450 MPa or more.

[0214] like Figure 5 As shown in FIG. 1 , the current collector 500 is related to the support layer 420 in that a plurality of through holes 522 are formed. Figure 4 The current collector 400 described above is different. The current collector 500 may have the same structure as the current collector 400 except for the above-mentioned difference.

[0215] When a simple metal foil is used as a current collector, if a through hole is to be formed in the current collector, the metal foil will bend, and it is sometimes difficult to form a through hole. Therefore, in particular, when an active material layer is formed on both sides of the metal foil, it is difficult to form a through hole in the current collector. In contrast, according to this embodiment, the conductive layer is supported by a supporting layer such as a resin sheet, so even if a through hole is formed in the current collector, the current collector is less likely to bend.

[0216] According to the present embodiment, a portion of the plurality of through holes 522 is filled with a conductive material 546 . The conductive material 546 electrically connects the conductive layer 442 and the conductive layer 444 .

[0217] The equivalent circle diameter (sometimes referred to as equivalent circle diameter) of each of the plurality of through holes 522 may be 15 μm to 150 μm. The interval between two adjacent through holes 522 may be 30 μm to 250 μm.

[0218] If the equivalent circular diameter of the through hole 522 is smaller than 15 μm, when a conductive layer (sometimes referred to as an internal conductive layer) for electrically connecting the conductive layer 442 and the conductive layer 444 is formed on the inner wall surface of the through hole 522, the thickness of the conductive layer formed on the inner wall surface becomes smaller, and the resistance of the conductive layer becomes larger. On the other hand, if the equivalent circular diameter of the through hole 522 is larger than 150 μm, when a conductive layer for electrically connecting the conductive layer 442 and the conductive layer 444 is formed on the inner wall surface of the through hole 522, the total amount of the conductive layer becomes smaller, and the resistance of the conductive layer 442 and the conductive layer 444 becomes larger. In addition, if the equivalent circular diameter of the through hole 522 is larger than 150 μm, there is a possibility that the strength of the collector 500 is insufficient.

[0219] The equivalent circular diameter (sometimes referred to as the equivalent circular diameter) of each of the plurality of through holes 522 may also be 15 μm to 150 μm, 15 μm to 50 μm, or 15 to 35 μm. The equivalent circular diameter of the through hole 522 not filled with the conductive material 546 may also be 15 μm to 50 μm, or 15 to 35 μm. The equivalent circular diameter of the through hole 522 filled with the conductive material 546 is not particularly limited. Thus, the breakage of the conductive layer 442 and the conductive layer 444 can be suppressed, and the metering of the collector 500 can be achieved.

[0220] The ratio of the total area of ​​the plurality of through holes 522 in one side of the current collector 500 to the area of ​​the outer shape of one side of the current collector 500 may also be 30% or more. The ratio of the total area of ​​the through holes 522 in one side of the current collector 500 that are not filled with the conductive material 546 to the area of ​​the outer shape of one side of the current collector 500 may also be 30% or more. Thus, the breakage of the conductive layer 442 and the conductive layer 444 can be suppressed, and the metering of the current collector 500 can be achieved.

[0221] like Figure 6 As shown in FIG. 1 , the current collector 600 is related to the support layer 420, the conductive layer 442, and the conductive layer 444 in that a plurality of through holes 620 are formed therein. Figure 5 The current collector 500 described above is different. The current collector 500 may have the same structure as the current collector 500 except for the above-mentioned difference.

[0222] In the present embodiment, a conductive layer 642 is formed on the surface of the inner wall portion 622 of at least a portion of the plurality of through holes 620. The conductive layer 642 may electrically connect the conductive layer 442 and the conductive layer 444.

[0223] In this embodiment, the conductive layer 642 includes a conductive material. The conductive material may also be a metal. Examples of the above-mentioned metal include aluminum, stainless steel, nickel, or alloys thereof. Examples of stainless steel include SUS-430, SUS-304, etc. The conductive material may also be aluminum.

[0224] The conductive layer 642 may also include multiple layers with different main components. The conductive layer 642 may also include three or more layers with different main components. The conductive layer 642 may include, for example, an auxiliary layer, a target layer, and a protective layer. For example, a first layer with nickel as the main component is formed on the surface of the inner wall portion 622 of the through hole 620, a second layer with copper as the main component is formed on the first layer, and a chrome-plated film is formed on the second layer. The thickness of the first layer may also be about 0.1 μm, the thickness of the second layer may also be about 1 μm, and the thickness of the chrome-plated film may also be about 0.3 μm.

[0225] The collector 400 may be an example of a sheet material. The collector 400 may be an example of a first sheet material, a second sheet material, or a third sheet material. The support layer 420 may be an example of a support layer. The conductive layer 442 may be an example of one of the first metal layer and the second metal layer. The conductive layer 444 may be an example of the other of the first metal layer and the second metal layer.

[0226] The current collector 500 may be an example of a sheet material. The current collector 500 may be an example of a first sheet material, a second sheet material, or a third sheet material.

[0227] The current collector 600 may be an example of a sheet material. The current collector 600 may be an example of a first sheet material, a second sheet material, or a third sheet material. The inner wall portion 622 may be an example of an inner wall of a through hole. The conductive layer 642 may be an example of a conductive layer disposed on the inner wall of the through hole. The conductive layer 642 may be an example of an internal conductive layer.

[0228] (An example of another embodiment)

[0229] In this embodiment, the details of the current collectors 400, 500, and 600 are described by taking as an example the case where the supporting layer 420 mainly contains a thermoplastic resin or is substantially composed of a thermosetting resin when a part of the stacked multiple current collectors are welded. However, the current collectors 400, 500, and 600 are not limited to this embodiment.

[0230] In other embodiments, when the conductive layer 442 and the conductive layer 444 disposed on both sides of the support layer 420 are electrically connected, the support layer 420 may also mainly contain a thermosetting resin, or may be substantially composed of a thermosetting resin. In particular, according to the collector 500, a conductive material 546 is filled inside at least a portion of the plurality of through holes 522. Similarly, according to the collector 600, a conductive layer 642 is formed inside at least a portion of the plurality of through holes 620. Therefore, even if a single collector conductive layer 442 and a conductive layer 444 are not close to or in contact, a portion of the stacked multiple collectors can be integrated by welding. In addition, the support layer is heated before welding, so that the fluidity of the support layer is reduced. Thus, the support layer is suppressed from being pressed out around the welding portion, and as a result, the volume expansion around the welding portion can be suppressed.

[0231] use Figure 7 as well as Figure 8 The details of a stacked structure 760 as another example of an electrode structure will be described. Figure 7 An example of a cross section of the stacked structure 760 is schematically shown. Figure 8 An example of the electrical connection relationship between electrodes of the stacked structure 760 is schematically shown.

[0232] In association Figure 2 In the embodiment described, the structure 260 in which the positive electrode 220, the separator 230, and the negative electrode 240 are stacked in sequence is used as an example to describe the details of the structure (sometimes referred to as the electrode structure) that constitutes a part of the battery. However, the electrode structure is not limited to the structure 260. The stacked structure 760 is different from the structure 260 in that it has a plurality of positive electrodes 220, a plurality of separators 230, and a plurality of negative electrodes 240. The stacked structure 760 may have the same configuration as the structure 260 except for the above-mentioned differences.

[0233] like Figure 7 As shown in FIG. 1 , in this embodiment, the stacked 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 7As shown, the stacked structure 760 includes a plurality of positive electrodes 220 , a plurality of negative electrodes 240 , and a plurality of separators 230 disposed between each of the plurality of positive electrodes 220 and each of the plurality of negative electrodes 240 .

[0234] Each of the plurality of positive electrodes 220 except the outermost positive electrode 220 disposed on the stacked structure 760 has a positive electrode active material layer 224 disposed on both sides of a positive electrode collector 222. The outermost positive electrode 220 disposed on the stacked structure 760 has a positive electrode active material layer 224 disposed on one side of the positive electrode collector 222.

[0235] Each of the plurality of negative electrodes 240 except the outermost negative electrode 240 disposed on the stacked structure 760 has a negative electrode active material layer 244 disposed on both sides of a negative electrode collector 242. The outermost negative electrode 240 disposed on the stacked structure 760 has a negative electrode active material layer 244 disposed on one side of the negative electrode collector 242.

[0236] In the present embodiment, the positive electrode active material layer 224 is disposed on a portion of the positive electrode collector 222. For example, near at least one end of the positive electrode collector 222, the positive electrode active material layer 224 is not formed on at least one side of the positive electrode collector 222. The plurality of positive electrodes 220 are stacked, for example, so that the ends of the side where the positive electrode active material layer 224 is not formed are oriented in substantially the same direction.

[0237] 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, near at least one end of the negative electrode current collector 242, the negative electrode active material layer 244 is not formed on at least one surface of the negative electrode current collector 242. The plurality of negative electrodes 240 are stacked, for example, so that the ends of the side where the negative electrode active material layer 244 is not formed are oriented in substantially the same direction.

[0238] like Figure 8 As shown, the stacked structure 760 includes a positive electrode connector 820 that electrically connects the plurality of positive electrodes 220. According to this embodiment, the positive electrode connector 820 includes a lead 822 and a sub-lead 824 that sandwich and support a portion of the plurality of positive electrodes 220. This improves the strength of the connection portion of the plurality of positive electrodes 220.

[0239] In this embodiment, the lead 822 and the sub-lead 824 sandwich and support the end and / or the vicinity of the end of each of the plurality of positive electrodes 220. As described above, the positive electrode active material layer 224 is not formed near at least one end of each of the plurality of positive electrodes 220. The lead 822 and the sub-lead 824 are arranged to sandwich the stacked plurality of positive electrode collectors 222. In addition, in other embodiments, the sub-lead 824 may not be used.

[0240] In the positive electrode connection portion 820, the plurality of positive electrodes 220 may also be physically combined by welding. For example, the stacked plurality of positive electrode collectors 222 are physically combined by welding, so that the ends and / or the vicinity of the ends of the plurality of positive electrode collectors 222 are integrated. Thus, the plurality of positive electrodes 220 are physically combined. At the ends and / or the vicinity of the ends of the plurality of positive electrode collectors 222, the plurality of positive electrode collectors 222 and the leads 822 and / or the sub-leads 824 may also be integrated. As welding methods, ultrasonic welding, resistance welding, laser welding, etc. are exemplified.

[0241] In this embodiment, the details of the stacked structure 760 are described by taking as an example the case where the positive electrode collectors 222 of each of the plurality of positive electrodes 220 are physically joined by welding the regions (sometimes referred to as welding regions) located near the ends of the positive electrode collectors 222 of each of the plurality of positive electrodes 220. In other embodiments, the welding regions may be arranged to include the ends of the positive electrode collectors 222 of each of the plurality of positive electrodes 220.

[0242] For example, if the association Figure 4 , Figure 5 or Figure 6 As described above, each of the plurality of positive electrode current collectors 222 includes a support layer 420 and a conductive layer 442 and a conductive layer 444 formed on both sides of the support layer 420. The conductive layer 442 and the conductive layer 444 are electrically connected, for example, by a conductive material 546 and / or a conductive layer 642. The composition or material of the support layer 420 may 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 may be the same or different from the composition or material of the support layer 420 of another positive electrode current collector 222.

[0243] In the present embodiment, the welding region is, for example, disposed near the ends of the plurality of positive electrode current collectors 222 and at least a portion of the region sandwiched by the lead 822 and the sub-lead 824. The sub-lead 824 may have a larger plane size than the welding region. The lead 822 may have a larger plane size than the sub-lead 824.

[0244] The lead wire 822 is made of, for example, a plate-shaped conductive material. The lead wire 822 may have a thickness of 10 to 300 μm, preferably 30 to 200 μm, and more preferably 50 to 100 μm.

[0245] The material of the sub-lead 824 is not particularly limited. The sub-lead 824 is made of, for example, aluminum, nickel, stainless steel, and alloys thereof. The sub-lead 824 may also be made of a resin material such as polypropylene or polyimide. The thickness of the sub-lead 824 may also be 10 to 300 μm, preferably 30 to 200 μm, and more preferably 50 to 100 μm.

[0246] Similarly, the stacked structure 760 includes a negative electrode connector 840 that electrically connects the plurality of negative electrodes 240. According to the present embodiment, the negative electrode connector 840 includes a lead 842 and a sub-lead 844 that sandwich and support a portion of the plurality of positive electrodes 220. This improves the strength of the connection portion of the plurality of negative electrodes 240.

[0247] In this embodiment, the lead 842 and the sub-lead 844 sandwich and support the end and / or the vicinity of the end of each of the plurality of negative electrodes 240. As described above, the negative electrode active material layer 244 is not formed near at least one end of each of the plurality of negative electrodes 240. The lead 842 and the sub-lead 844 are arranged to sandwich the stacked plurality of negative electrode collectors 242. In other embodiments, the sub-lead 844 may not be used.

[0248] In the negative electrode connection portion 840, the plurality of negative electrodes 240 may also be physically combined by welding. For example, the stacked plurality of negative electrode collectors 242 are physically combined by welding, so that the ends and / or the vicinity of the ends of the plurality of negative electrode collectors 242 become one. Thus, the plurality of negative electrodes 240 are physically combined. Alternatively, the plurality of negative electrode collectors 242 may be integrated with the lead 842 and / or the sub-lead 844 at the ends and / or the vicinity of the ends of the plurality of negative electrode collectors 242. As welding methods, ultrasonic welding, resistance welding, laser welding, etc. are exemplified.

[0249] According to the present embodiment, the details of the stacked structure 760 are described by taking as an example the case where the negative electrode collectors 242 of each of the plurality of negative electrodes 240 are physically joined by welding the regions (sometimes referred to as welding regions) located near the ends of the negative electrode collectors 242 of each of the plurality of negative electrodes 240. In other embodiments, the welding regions may be arranged to include the ends of the negative electrode collectors 242 of each of the plurality of negative electrodes 240.

[0250] For example, if the association Figure 4 , Figure 5 or Figure 6As described above, each of the plurality of negative electrode current collectors 242 includes a support layer 420 and a conductive layer 442 and a conductive layer 444 formed on both sides of the support layer 420. The conductive layer 442 and the conductive layer 444 are electrically connected, for example, by a conductive material 546 and / or a conductive layer 642. The composition or material of the support layer 420 may be the same or different between each of the plurality of negative electrode current collectors 242. The composition or material of the support layer 420 of one negative electrode current collector 242 may be the same or different from the composition or material of the support layer 420 of another negative electrode current collector 242.

[0251] In the present embodiment, the welding region is, for example, disposed near the ends of the plurality of negative electrode current collectors 242 and at least a portion of the region sandwiched by the lead 842 and the sub-lead 844. The sub-lead 844 may have a larger plane size than the welding region. The lead 842 may have a larger plane size than the sub-lead 844.

[0252] The lead wire 842 is made of, for example, a plate-shaped conductive material and may have a thickness of 10 to 300 μm, preferably 30 to 200 μm, and more preferably 50 to 100 μm.

[0253] The material of the sub-lead 844 is not particularly limited. The sub-lead 844 is made of, for example, aluminum, nickel, stainless steel, and alloys thereof. The sub-lead 844 may also be made of a resin material such as polypropylene or polyimide. The thickness of the sub-lead 844 may also be 10 to 300 μm, preferably 30 to 200 μm, and more preferably 50 to 100 μm.

[0254] The lead 822 and the sub-lead 824 may be an example of a positive electrode support portion. The lead 842 and the sub-lead 844 may be an example of a negative electrode support portion.

[0255] The lead 822 may be an example of a first supporting member. The sub-lead 824 may be an example of a second supporting member. The lead 842 may be an example of a first supporting member. The sub-lead 844 may be an example of a second supporting member. The stacked structure 760 may be an example of an electrode structure. The plurality of positive electrode current collectors 222 included in the stacked structure 760 may be an example of a plurality of stacked sheet materials. The plurality of negative electrode current collectors 242 included in the stacked structure 760 may be an example of a plurality of stacked sheet materials.

[0256] The positive current collector 222 in contact with the lead 822 among the plurality of positive current collectors 222 stacked in the positive electrode connection portion 820 may be an example of the first sheet material or the third sheet material. The positive current collector 222 in contact with the sub-lead 824 among the plurality of positive current collectors 222 stacked in the positive electrode connection portion 820 may be an example of the second sheet material or the third sheet material. The negative current collector 242 in contact with the lead 842 among the plurality of negative current collectors 242 stacked in the negative electrode connection portion 840 may be an example of the first sheet material or the third sheet material. The negative current collector 242 in contact with the sub-lead 844 among the plurality of negative current collectors 242 stacked in the negative electrode connection portion 840 may be an example of the second sheet material or the third sheet material.

[0257] Alternatively, the plurality of positive electrodes 220 included in the stacked structure 760 may be an example of the first electrode and the second electrode, and the plurality of negative electrodes 240 included in the stacked structure 760 may be an example of the third electrode and the fourth electrode. Alternatively, the plurality of positive electrodes 220 included in the stacked structure 760 may be an example of the third electrode and the fourth electrode, and the plurality of negative electrodes 240 included in the stacked structure 760 may be an example of the first electrode and the second electrode. Alternatively, the plurality of separators 230 included in the stacked structure 760 may be an example of the first separator, the second separator, and the third separator.

[0258] (An example of another embodiment)

[0259] In this embodiment, the stacked structure 760 is described in detail by taking the case where the stacked structure 760 includes the positive electrode connection portion 820 and the negative electrode connection portion 840 as an example. However, the stacked structure 760 is not limited to this embodiment. In other embodiments, the stacked structure 760 may also include at least one of the positive electrode connection portion 820 and the negative electrode connection portion 840.

[0260] In this embodiment, the details of the positive electrode connection part 820 are described by taking the case where the plurality of positive electrode current collectors 222 are supported by the lead 822 and the sub-lead 824 in the positive electrode connection part 820 as an example. However, the positive electrode connection part 820 is not limited to this embodiment. In other embodiments, the positive electrode connection part 820 may not include the sub-lead 824. In this case, the plurality of positive electrode current collectors 222 are supported by the lead 822.

[0261] In this embodiment, the details of the negative electrode connection part 840 are described by taking the case where the plurality of negative electrode current collectors 242 are supported by the lead 842 and the sub-lead 844 in the negative electrode connection part 840 as an example. However, the negative electrode connection part 840 is not limited to this embodiment. In other embodiments, the negative electrode connection part 840 may not include the sub-lead 844. In this case, the plurality of negative electrode current collectors 242 are supported by the lead 842.

[0262] Fig. 9 An example of a method for manufacturing a battery cell 112 is schematically shown. In the present embodiment, a method for producing a battery cell 112 having a stacked structure 760 is described. According to the present embodiment, first, in step 912 (sometimes the step is abbreviated as S.), a plurality of positive electrodes 220 and a plurality of negative electrodes 240 are prepared. The details of the method for preparing the positive electrode 220 or the negative electrode 240 will be described later. In addition, 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 stacked in sequence. Thus, a stacked structure 760 is produced.

[0263] Next, in S932, the plurality of positive electrodes 220 of the stacked structure 760 are electrically connected. Furthermore, in S934, the plurality of negative electrodes 240 of the stacked structure 760 are electrically connected. Thereafter, in S940, the stacked structure 760 is housed inside the positive electrode case 212 and the negative electrode case 214, and the battery cell 112 is assembled.

[0264] Alternatively, the plurality of positive electrodes 220 prepared in S912 may be an example of the first electrode and the second electrode, and the plurality of negative electrodes 240 prepared in S912 may be an example of the third electrode and the fourth electrode. Alternatively, the plurality of positive electrodes 220 prepared in S912 may be an example of the third electrode and the fourth electrode, and the plurality of negative electrodes 240 prepared in S912 may be an example of the first electrode and the second electrode. Alternatively, the plurality of separators 230 prepared in S914 may be an example of the first separator, the second separator, and the third separator. The stacked structure 760 may 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 stacked in sequence.

[0265] Fig.10 An example of a method for manufacturing the positive electrode 220 is schematically shown. According to the present embodiment, first, in S1010, a positive electrode collector 222 is prepared. Next, in S1022, a positive electrode slurry containing a positive electrode active material and a solvent is adjusted. Next, in S1024, the positive electrode slurry is applied to the surface of the positive electrode collector 222. In addition, the positive electrode slurry is dried. Thus, a positive electrode active material layer 224 is formed on the surface of the positive electrode collector 222.

[0266] Next, in S1030, the positive electrode active material layer 224 and the positive electrode collector 222 are fixedly bonded. More specifically, pressure is applied to the stacked positive electrode active material layer 224 and the positive electrode collector 222 to thereby fix the positive electrode active material layer 224 and the positive electrode collector 222.

[0267] In one embodiment, the pressure in the fixing process can also be set or adjusted so that (i) the rate of change of the resistance (resistance) of the collector before and after the pressure is applied to the active material layer and the collector is within 50% or (ii) the absolute value of the difference in the resistance (resistance) of the collector before and after the pressure is applied to the active material layer and the collector is 1 [Ω] or less. The pressure in the fixing process can also 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 less than 500m [Ω], and is further preferably set or adjusted so that the absolute value of the above difference is less than 100m [Ω]. Thereby, the fracture of the conductive layer of the collector is suppressed. The resistance of the above-mentioned collector can be measured, for example, by a 4-terminal 4-probe method using a low resistivity meter (manufactured by Nitto Seiko Analytech Co., Ltd., Lorestar-GX MCP-T700).

[0268] In other embodiments, the pressure in the fixing process is set or adjusted so that the value obtained by subtracting the value of the first voltage measured by applying current to the conductive layer of the collector before the pressure is applied from the value of the second voltage measured by applying current (i) to the conductive layer of the collector after the pressure is applied is less than 100mV. Thus, the fracture of the conductive layer of the collector is suppressed. The above-mentioned first voltage and second voltage are measured, for example, by a low resistivity meter having a voltage value measurement function and an output function. The above-mentioned first voltage and second voltage can be measured, for example, by a 4-terminal 4-probe method using a low resistivity meter (manufactured by Nitto Seiko Analytech Co., Ltd., Lorestar-GX MCP-T700).

[0269] In other embodiments, the pressure in the fixing step is set or adjusted so that the porosity of the active material layer after the pressure is applied becomes 20 to 40%, thereby suppressing the breakage of the conductive layer of the current collector.

[0270] For example, when a roller press is used to apply pressure to the positive electrode active material layer 224 and the positive electrode current collector 222, the roller press is controlled so that the linear pressure applied to the positive electrode active material layer 224 and the positive electrode current collector 222 becomes 1.0kgf / cm to 200kgf / cm. The roller press may also be controlled so that the linear pressure becomes 2kgf / cm to 150kgf / cm, or the roller press may be controlled so that the linear pressure becomes 10kgf / cm to 100kgf / cm. Thus, the positive electrode current collector 222 having the above-mentioned characteristics is produced.

[0271] (The process of physically combining multiple electrodes)

[0272] use Fig.11 , Fig.12, Fig.13 as well as Fig.14 , an example of a process of physically combining multiple electrodes is described. For example, as shown in FIG. Figure 8 as well as Fig. 9 As described above, according to one embodiment of the stacked structure 760, in the positive electrode connection portion 820, the plurality of positive electrodes 220 are physically connected by welding. For example, the positive electrode collectors 222 of the plurality of positive electrodes 220 are physically connected by welding. According to one embodiment of the stacked structure 760, in the negative electrode connection portion 840, the plurality of negative electrodes 240 are physically connected by welding. For example, the negative electrode collectors 242 of the plurality of negative electrodes 240 are physically connected by welding.

[0273] In this embodiment, in order to facilitate understanding of the process of physically combining multiple electrodes, the details of the process of physically combining multiple electrodes are described by taking the case where a welding device 1120 is used to combine parts of two positive electrodes 220 by welding as an example. In addition, the number of electrodes combined by welding is not limited to 2. In other embodiments, three or more electrodes may be combined by welding.

[0274] In addition, in this embodiment, in order to facilitate understanding of the process of physically combining a plurality of electrodes, details of the process of physically combining a plurality of electrodes are described by taking as an example a case where one positive electrode 220 includes 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 includes a current collector 1104 and a positive electrode active material layer 224 disposed on at least one side of the current collector 1104. In this embodiment, details of the process of physically combining a plurality of electrodes are described by taking as an example a case where the positive electrode active material layer 224 is not formed near the ends of the current collector 1102 and the current collector 1104.

[0275] Fig.11 An example of the system configuration of the welding device 1120 is shown together with an example of the end portions and / or the vicinity thereof of the current collector 1102 and the current collector 1104. Fig.11 , an example of a welding process using the welding device 1120 is described. More specifically, using Fig.11 An example of a process in which welding device 1120 welds a portion of the vicinity of the end portions of current collector 1102 and current collector 1104 while pressing the end portions and the vicinity of the end portions to produce positive electrode connecting portion 820 will be described.

[0276] (Welding object)

[0277] In this embodiment, the current collector 1102 and the current collector 1104 to be welded have a Figure 6 The collector 600 described above has the same structure. Figure 6 As described above, the current collector 600 includes the support layer 420 and the conductive layer 442 and the conductive layer 444 formed on both sides of the support layer 420. The current collector 600 is formed with a plurality of through holes 620 penetrating the support layer 420, the conductive layer 442, and the conductive layer 444. The shape of the through hole 620 is not particularly limited. The conductive layer 642 that electrically connects the conductive layer 442 and the conductive layer 444 is formed on the surface of the inner wall portion 622 of at least a portion of the plurality of through holes 620.

[0278] In this embodiment, the current collector 1102 and the supporting layer 420 of the current collector 1104 include a thermoplastic resin material (sometimes referred to as a thermoplastic resin). In this embodiment, the current collector 1102 and the supporting layer 420 of the current collector 1104 may also be a resin layer substantially composed of a thermoplastic resin material. The current collector 1102 and the supporting layer 420 of the current collector 1104 may also be an insulating layer substantially composed of a thermoplastic resin material.

[0279] 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 while the resin material contained in the support layer 420 is softened, the resin material can move inside the support layer 420. The type of the energy is not particularly limited as long as it can increase the temperature of the support layer 420 and / or the resin material contained in the support layer 420. The energy may also be thermal energy.

[0280] The thermoplastic resin material may be a resin material having a heat shrinkage rate of 1% or less at 25° C. Examples of the thermoplastic resin material include PE, PET, PAN, PP, and PPS.

[0281] The thickness of the supporting layer 420 of the current collector 1102 and the current collector 1104 may be 0.5 μm to 20 μm. The thickness of the supporting layer 420 is preferably 1 μm to 10 μm, and more preferably 2 μm to 8 μm.

[0282] In this embodiment, the conductive layers 442 and 444 of the current collector 1102 and the current collector 1104 respectively include a metal material. The conductive layers 442 and 444 of the current collector 1102 and the current collector 1104 respectively may also be metal layers substantially composed of metal materials. The metal layer substantially composed of metal materials may contain unavoidable impurities, for example. The metal material contained in the conductive layers 442 and 444 may be a single substance of a metal or an alloy.

[0283] The thickness of the conductive layer 442 and the conductive layer 444 of the current collector 1102 and the current collector 1104 may be 0.1 μm to 10 μm. The thickness of the conductive layer 442 and the conductive layer 444 is preferably 0.1 μm to 5 μm, and more preferably 0.1 μm to 1 μm.

[0284] In this embodiment, conductive layers 442 and 444 of current collectors 1102 and 1104 are electrically connected. Thus, welding current applied to conductive layer 442 of current collector 1102 by welding device 1120 flows through conductive layers 442 and 444 of current collectors 1102 and 1104, respectively.

[0285] The conductive layer 442 and the conductive layer 444 may be electrically connected in any manner. In one embodiment, a conductive member electrically connecting the conductive layer 442 and the conductive layer 444 is disposed on the side 426 of the support layer 420. In other embodiments, a conductive member electrically connecting the conductive layer 442 and the conductive layer 444 is disposed inside the support layer 420.

[0286] In this embodiment, a plurality of through holes 620 penetrating the support layer 420, the conductive layer 442, and the conductive layer 444 of the current collector 1102 are formed in a portion of the current collector 1102. At least a portion of the plurality of through holes 620 is disposed in the above-mentioned welding region ( Fig.11 , represented by Rw.). As a result, the amount of resin material present in the welding region of the support layer 420 is reduced compared to the case where no through hole, groove or recess is formed in the welding region of the support layer 420. As a result, the amount of resin material pushed away by welding the conductive layer 442 and the conductive layer 444 is reduced, and the volume expansion of the periphery of the welding region accompanying welding is suppressed.

[0287] According to the present embodiment, through holes 620 are also formed in the conductive layers 442 and 444. Thus, the resin material pushed away by welding the conductive layers 442 and 444 can flow into the through holes 620 provided in the conductive layers 442 and 444. As a result, the volume expansion of the periphery of the welding region accompanying welding is suppressed.

[0288] At least a portion of the plurality of through holes 620 may also be disposed in a region adjacent to the welding region (sometimes referred to as an adjacent region). As described above, along with the welding of the conductive layers 442 and 444, a portion of the resin material present in the welding region before welding is pushed away and moves toward the adjacent region. According to the present embodiment, the through holes 620 are formed in the adjacent region, so that the resin material pushed away along with the welding of the conductive layers 442 and 444 can flow into the inside of the through holes 620 disposed in the adjacent region. As a result, the volume expansion of the periphery of the welding region accompanying welding is suppressed.

[0289] At least a portion of the plurality of through holes 620 may be disposed in the welding region and the region adjacent to the welding region. This further suppresses the volume expansion of the periphery of the welding region accompanying welding. The details of the through holes 620 will be described later.

[0290] In this embodiment, a conductive layer 642 that electrically connects the conductive layer 442 and the conductive layer 444 is disposed on the surface of the inner wall portion 622 of at least a portion of the plurality of through holes 620. The material constituting the conductive layer 642 is any material having conductivity, and its type and structure are not particularly limited. The conductive layer 642 may also include a metal material. The conductive layer 642 may also be a metal layer substantially composed of a metal material. The metal layer substantially composed of a metal material may contain, for example, unavoidable impurities.

[0291] The metal material contained in the conductive layer 642 may be a single substance of metal or an alloy. The metal material contained in the conductive layer 642 may 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. Examples of the above-mentioned metal materials include copper, nickel, aluminum, stainless steel, and alloys thereof. Examples of stainless steel include SUS304, SUS430, and the like.

[0292] Conductive layer 642 may also include multiple layers. Each of the multiple layers may also be composed of different materials. For example, conductive layer 642 may also include: a layer (sometimes referred to as a target layer) for electrically connecting conductive layer 442 and conductive layer 444 and an auxiliary layer disposed between inner wall portion 622 of through hole 620 and the target layer. The auxiliary layer is formed to assist the conductivity of the target layer or to improve the adhesion between through hole 620 and the target layer. A protective layer for protecting the target layer may also be formed on the surface of the target layer. Examples of the protective layer include chrome plating, zinc film, etc.

[0293] The conductive layer 642 may also include an auxiliary layer, a target layer, and a protective layer. For example, a first layer mainly composed of nickel is formed on the surface of the inner wall portion 622 of the through hole 620, a second layer mainly composed of copper is formed on the first layer, and a chrome-plated film is formed on the second layer. The thickness of the first layer may be about 0.1 μm, the thickness of the second layer may be about 1 μm, and the thickness of the chrome-plated film may be about 0.3 μm.

[0294] As described above, the thickness of the conductive layer 642 of the current collector 1102 and the current collector 1104 may be 0 μm to 5 μm. The thickness of the conductive layer 642 is preferably 0.1 μm to 3 μm, and more preferably 0.1 μm to 1 μm.

[0295] The conductive layer 642 is formed by a known method. For example, the conductive layer 642 is formed by chemical plating, evaporation, or sputtering. The conductive layer 642 may also be formed by various secondary growth methods, or by attaching a metal foil to the surface of the inner wall portion 622 of the through hole 620.

[0296] Similarly, a plurality of through holes 620 penetrating 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. A conductive layer 642 that electrically connects the conductive layer 442 and the conductive layer 444 is disposed on the surface of the inner wall portion 622 of at least a portion of the plurality of through holes 620. The conductive layer 642 of the current collector 1104 may also have the same features as those described in connection with the conductive layer 642 of the current collector 1102.

[0297] (Supporting member)

[0298] As described above, the conductive layer 442 and the conductive layer 444 involved in this embodiment are formed of a metal thin film, and therefore have relatively low strength. Figure 8 The lead 822 and the sub-lead 824 described above support the current collector 1102 and the current collector 1104. In the present embodiment, the lead 822 and the sub-lead 824 are arranged so as to sandwich the stacked current collector 1102 and the current collector 1104. This prevents the metal thin film from breaking during welding.

[0299] As described above, a conductive member is used as the lead 822. On the other hand, a conductive or non-conductive member is used as the sub-lead 824.

[0300] (Welding equipment)

[0301] In the present embodiment, the welding device 1120 includes a pair of welding heads 1130, a heating power source 1140, a welding power source 1150, and a controller 1160. In the present embodiment, the welding device 1120 includes a pair of heating power sources 1140 that supply power to the pair of welding heads 1130. In the present embodiment, the welding head 1130 includes a position adjustment unit 1132, a heating unit 1134, and a welding unit 1136.

[0302] In this 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.

[0303] In this embodiment, the position adjustment unit 1132 adjusts the position of the welding head 1130. For example, the position adjustment unit 1132 moves the welding head 1130 to the welding area of ​​the welding object. For example, the position adjustment unit 1132 presses the welding head 1130 to the welding area of ​​the welding object. As a result, pressure is applied to the welding area of ​​the welding object.

[0304] In this embodiment, the heating unit 1134 applies energy to the softened area of ​​the welding object, thereby heating the softened area of ​​the welding object. In this embodiment, the welding unit 1136 applies current and / or voltage to the welding area of ​​the welding object, thereby welding the welding area of ​​the welding object.

[0305] In the present embodiment, the heating power source 1140 supplies power to the heating unit 1134. In the present embodiment, the welding power source 1150 supplies power to the position adjustment unit 1132 and the welding unit 1136. In the present embodiment, the controller 1160 controls the operation of each part of the welding device 1120.

[0306] (Welding process)

[0307] Next, an example of a process of welding a part of the current collector 1102 and the current collector 1104 using the welding device 1120 is described. According to this 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-mentioned structure are manufactured. In other embodiments, the current collector 1102 and the current collector 1104 having the above-mentioned structure are purchased.

[0308] Next, a stacked body is prepared in which the current collector 1102 and the current collector 1104 are partially joined by welding. More specifically, first, the current collector 1102 and the current collector 1104 are stacked. For example, the current collector 1102 and the current collector 1104 are stacked in such a manner that the second plane 424 side of the current collector 1102 is in contact with the first plane 422 side of the current collector 1104.

[0309] In one embodiment, the plurality of through holes 620 of the current collector 1102 are aligned with the plurality of through holes 620 of the current collector 1104. In other embodiments, the plurality of through holes 620 of the current collector 1102 are not aligned with the plurality of through holes 620 of the current collector 1104.

[0310] Next, the current collector 1102 and the current collector 1104 are reinforced using the lead 822 and the sub-lead 824. For example, the current collector 1102 and the current collector 1104 and the lead 822 and the sub-lead 824 are set at the working position of the welding device 1120 in such a manner that the lead 822 and the sub-lead 824 sandwich the welding area of ​​the current collector 1102 and the current collector 1104 or the area around it.

[0311] Next, the weld region of the current collector 1102 and the current collector 1104 is determined. In addition, a region including the weld region of the stacked current collector 1102 and the current collector 1104 and to be subjected to heat treatment (for example, Fig.11 In the figure, the softening region is represented by Rs. ).

[0312] For example, the user of the welding device 1120 operates the welding device 1120 and inputs the positions of the welding area and the softening area to the welding device 1120. The controller 1160 of the welding device 1120 controls the position adjustment unit 1132 to move the welding head 1130 to any position (for example, the welding area) of the softening area of ​​the current collector 1102 and the current collector 1104. The controller 1160 of the welding device 1120 controls the position adjustment unit 1132 to bring the welding head 1130 into contact with the softening area of ​​the current collector 1102 and the current collector 1104.

[0313] Next, energy is applied to the region (sometimes referred to as a softened region) including the welded region of the stacked current collector 1102 and the current collector 1104 to soften the resin material in the softened region. For example, the controller 1160 of the welding device 1120 controls the heating power supply 1140 to supply power from the heating power supply 1140 to the heating unit 1134. As a result, the heating unit 1134 raises the temperature of the welding head 1130. As a result, thermal energy is applied from the welding head 1130 to the softened regions of the current collector 1102 and the current collector 1104.

[0314] As described above, in this embodiment, the supporting layer 420 of the current collector 1102 and the current collector 1104 contains a thermoplastic resin. When thermal energy is applied to the softened regions of the current collector 1102 and the current collector 1104, the thermoplastic resin disposed in the softened regions softens.

[0315] Next, the welding region disposed at least in part of the softened region is pressed. For example, the controller 1160 of the welding device 1120 controls the position adjustment unit 1132 to press the welding head 1130 to the welding region.

[0316] For example, the controller 1160 controls the position adjustment unit 1132 to bring the conductive layers 442 and 444 of the current collector 1102 and the current collector 1104 close to a distance that allows welding. At this time, pressure is also applied to the thermoplastic resin disposed between the conductive layers 442 and 444. According to the present embodiment, the thermoplastic resin softens 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 of the conductive layer 442 and the conductive layer 444 formed in the welding area and / or the outside of the welding area.

[0317] The controller 1160 of the welding device 1120 can also control the position adjustment unit 1132 to apply pressure to the stacked collectors 1102 and 1104 in such a manner that the softened resin material flows into the through-holes 620 provided in at least a portion of the softened region and / or the welding region. Thus, the volume expansion of the periphery of the welding region accompanying welding is significantly suppressed.

[0318] The controller 1160 may also control the position adjustment unit 1132 to apply pressure to the stacked collectors 1102 and 1104 in such a manner that the softened resin material breaks the conductive layer 642 on the surface of the inner wall portion 622 of the through hole 620 disposed in at least a portion of the softened region and / or the welding region and flows into the inside of the through hole 620. Thus, the volume expansion of the periphery of the welding region accompanying welding is significantly suppressed.

[0319] Next, a current and / or a voltage is applied to the pressed welding region. Thus, the conductive layers 442 and 444 of the current collector 1102 and the current collector 1104 are welded. In addition, for example, the conductive layer 444 of the current collector 1102 is welded to the conductive layer 442 of the current collector 1104. As a result, a laminated body in which a part of the conductive layer 442 and the conductive layer 444 of the current collector 1102 and the current collector 1104 are integrated is produced.

[0320] For example, the controller 1160 of the welding device 1120 controls the welding power source 1150 to supply power to the welding portion 1136. As a result, a current and / or a voltage is applied to the pressed welding region, and a welding current flows through the conductive layers 442 and 444 of the current collectors 1102 and 1104, respectively. At this time, the controller 1160 of the welding device 1120 may control the position adjustment unit 1132 and the welding power source 1150 to further press the welding region while applying a current and / or a voltage to the welding region.

[0321] 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 via the conductive layer 642. Thus, a welding current flows through 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, the four conductive layers are integrated in at least a portion of the weld region.

[0322] Thus, a laminated body 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 near the end of one side of the current collector 1102 and the current collector 1104 is produced. Thermoplastic resin may also exist in the region (sometimes referred to as the integrated region) in which a portion of the conductive layers 442 and 444 are integrated. Voids may also exist in the integrated region. Thus, a laminated body in which at least one of the thermoplastic resin and the voids is dispersed inside the integrated metal may also be produced.

[0323] In the integrated region, the conductive layer 442 and the conductive layer 444 may have shapes different from those before welding. Similarly, the thermoplastic resin contained in the support layer 420 may have shapes different from those before welding. A portion of the integrated region may include the conductive layer 442, the conductive layer 444 and / or the support layer 420 that maintain substantially the same shapes as before welding.

[0324] In the case where the lead 822 is made of metal, a laminated body may be produced in which the lead 822, the conductive layer 442 and the conductive layer 444 of the collector 1102, and the conductive layer 442 and the conductive layer 444 of the collector 1104 are integrated. In this case, the integrated region means a region in which the lead 822, the conductive layer 442, and a portion of the conductive layer 444 are integrated. Similarly, in the case where the lead 822 and the sub-lead 824 are made of metal, a laminated body may be produced in which the lead 822, the conductive layer 442 and the conductive layer 444 of the collector 1102, the conductive layer 442 and the conductive layer 444 of the collector 1104, and the sub-lead 824 are integrated. In this case, the integrated region means a region in which the lead 822, the conductive layer 442, the conductive layer 444, and a portion of the sub-lead 824 are integrated.

[0325] As described above, a plurality of through holes 620 are formed in the welding region of the current collector 1102. Similarly, a plurality of through holes 620 are formed in the welding region of the current collector 1104. During welding, a portion of the plurality of through holes 620 is filled with the metal contained in the conductive layer 442, the conductive layer 444 and / or the conductive layer 642. As a result, a portion of the plurality of through holes 620 disappears, or the volume of the voids in a portion of the plurality of through holes 620 is reduced. Similarly, during welding, a portion of the plurality of through holes 620 is filled with the thermoplastic resin contained in the supporting layer 420. As a result, a portion of the plurality of through holes 620 disappears, or the volume of the voids in a portion of the plurality of through holes 620 is reduced. As a result, depending on the conditions and / or conditions during welding, thermoplastic resin and / or voids sometimes remain in the integrated region.

[0326] In addition, the integrated region may not contain thermoplastic resin, and the integrated region may not contain voids. For example, by adjusting the degree of pressure during welding and / or the magnitude of the welding current, a laminated body containing no thermoplastic resin and / or voids in the integrated region can be produced.

[0327] (Resin content in integrated area)

[0328] 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 in the integrated region) may be 0%, or 0.1 to 50%. The above-mentioned resin content is preferably 0.1 to 50%, more preferably 1 to 30%, and further preferably 5 to 20%.

[0329] When the lead 822 and / or the sub-lead 824 are made of metal and the lead 822 and / or the sub-lead 824, 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 are integrated, the resin content 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 derived from the conductive layer 442 and the conductive layer 444 present in the integrated region. The volume of the metal derived from the conductive layer 442, the conductive layer 444, and / or the conductive layer 642 may be the volume of the same type of metal as the component (sometimes referred to as the main component) that mainly constitutes the conductive layer 442, the conductive layer 444, and / or the conductive layer 642.

[0330] For example, when the main components of lead 822 and / or sub-lead 824, the main components of conductive layer 442 and conductive layer 444 of collector 1102, and the main components of conductive layer 442 and conductive layer 444 of collector 1104 are different, the boundary between the metal derived from lead 822 and / or sub-lead 824 and the metal derived from conductive layer 442 and / or conductive layer 444 can be observed by using a scanning electron microscope (SEM), for example, by using the stacking direction ( Fig.11 The same also applies when the main components of lead 822 and / or sub-lead 824 are different from the main components of conductive layer 442, conductive layer 444, and conductive layer 642 of collector 1102, and the main components of conductive layer 442, conductive layer 444, and conductive layer 642 of collector 1104 are different.

[0331] For example, in the case where the main component of lead 822 and / or sub-lead 824 is the same as or similar to the main component of conductive layer 442 and / or conductive layer 444, it is also considered difficult to determine the position of the above-mentioned boundary based on observation of the cross section of the integrated region. In this case, the position of the above-mentioned boundary can also be inferred based on the position of the boundary between lead 822 and / or sub-lead 824 and conductive layer 442 and / or conductive layer 444 in the adjacent region where the metal derived from lead 822 and / or sub-lead 824 and the metal derived from conductive layer 442 and / or conductive layer 444 are not integrated.

[0332] The above-mentioned resin content may also be 5 to 50%. The above-mentioned resin content is preferably 5 to 30%, and more preferably 5 to 20%. According to this embodiment, a through hole 620 is formed in the softening region and / or the welding region. Therefore, compared with the case where the through hole 620 is not formed in the softening region and / or the welding region, the above-mentioned resin content may be increased. In addition, a relatively large resin content may indicate that a through hole 620 is formed in the softening region and / or the welding region.

[0333] If the resin content exceeds 50%, welding is insufficient and the durability of the welded portion is reduced. In addition, if the resin content exceeds 50%, the conductivity between the lead 822 and the sub-lead 824 is reduced and the resistance is increased. On the other hand, in the case where the integrated region contains an appropriate amount of resin, the resin can contribute to ensuring the strength of the integrated region. In addition, in this case, the integrated region contains a sufficient amount of conductive material, and therefore, the conductivity of the integrated region is ensured.

[0334] The ratio of the volume of the thermoplastic resin derived from the support layer 420 in the resin present in the integration region to the volume of the metal derived from the conductive layer 442, the conductive layer 444, and / or the conductive layer 642 in the metal present in the integration region may also be 5 to 50%. The above ratio may also be 10 to 50%, 10 to 40%, or 5 to 30%. As described above, for example, when 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 collector 1102 and the main component of the conductive layer 442 and the conductive layer 444 of the collector 1104, the volume of the metal derived from the conductive layer 442, the conductive layer 444, and / or the conductive layer 642 in the metal present in the integration region can be determined relatively easily by observation based on a scanning electron microscope.

[0335] As described above, the resin content in the integrated region is determined by observing, for example, the stacking direction ( Fig.11 The cross section (in other words, the SEM observation surface) can also be determined by using the stacking direction ( Fig.11 ) is substantially parallel to the extending direction of the plurality of current collectors ( Fig.11 ) roughly perpendicular to the left and right direction. Fig.11 A plane that passes through the paper plane approximately perpendicularly. ) A cross section obtained by cutting the integrated region.

[0336] The above-mentioned cross section may also be a plane passing through the approximate center of the integrated region. The approximate center of the integrated region is determined by visually observing the surface of one side (e.g., the first plane 422) of the integrated multiple current collectors. The above-mentioned surface may also be the surface on the first plane 422 side of the current collector disposed on the uppermost surface, or the surface on the second plane 424 side of the current collector disposed on the lowermost surface.

[0337] In the stage of cutting the integrated region of the stacked body in order to observe the cross section of the stacked body using SEM, the approximate position of the outer edge of the integrated region is determined by, for example, visually observing the welding marks. In addition, the exact position of the outer edge of the integrated region is determined by, for example, cutting the integrated region of the stacked body and then observing the cross section using SEM.

[0338] According to one embodiment, by appropriately adjusting the magnification of the SEM image near the outer edge of the integrated region, the region where the plurality of conductive layers are integrated and the region where the plurality of conductive layers are merely in contact but not integrated can be distinguished by visual observation. Thus, the position of the outer edge (sometimes referred to as the end) of the integrated region can be determined.

[0339] According to other embodiments, the position of the outer edge of the integrated region is determined based on the length (sometimes referred to as thickness) of the stack in the stacking direction of the multiple collectors. For example, the position where the thickness near the end of the integrated region becomes 1.1 times the average value of the thickness near the center of the integrated region (for example, Hu described later) is determined as the end of the integrated region. The thickness near the center of the integrated region is determined, for example, by averaging the thickness at the positions of three locations in the SEM image near the center of the integrated region. In the case where multiple collectors are welded using leads and sub-leads, the thickness of the integrated region may also be the distance between the leads and the sub-leads.

[0340] The resin content in the integrated region is derived as, for example, the ratio of the area of ​​the thermoplastic resin in the SEM image to the area of ​​the metal in the SEM image. The resin content in the integrated region can also be derived as the average value of the resin content obtained by observing multiple SEMs with different observation positions in a single cross section. For example, first, 5 resin contents corresponding to each of the 5 SEM images are derived. Next, 3 measured values ​​excluding the maximum and minimum measured values ​​among the 5 measured values ​​of the resin content are averaged. Thus, the resin content in the integrated region is determined. One of the multiple SEM images can also be an image of the approximate center of the integrated region.

[0341] (Porosity in the integrated area)

[0342] The ratio of the volume of the voids in the integrated region to the volume of the metal (sometimes referred to as the void ratio in the integrated region) may also be 0 to 10%. The void ratio in the integrated region is preferably 0 to 10%, more preferably 0.1 to 8%, and further preferably 0.1 to 5%. The void ratio in the integrated region may also exceed 10%, but if the void ratio becomes larger, the strength and conductivity of the integrated region decrease. Therefore, the void ratio in the integrated region is preferably 10% or less.

[0343] According to the present embodiment, a through hole 620 is formed in the softened region and / or the welded region. Therefore, the above-mentioned void ratio may be increased compared to the case where the through hole 620 is not formed in the softened region and / or the welded region. In addition, a relatively large void ratio may indicate that the through hole 620 is formed in the softened region and / or the welded region.

[0344] The porosity in the integrated region is determined by observing the stacking direction (in the direction of the stacking direction) of the integrated multiple current collectors using, for example, a scanning electron microscope (SEM). Fig.11 The porosity in the integrated region is determined by, for example, the same process as the resin content in the integrated region.

[0345] As described above, the above-mentioned stacked body constitutes a part of the stacked structure 760. Figure 8 As described above, 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 in this order.

[0346] In the present embodiment, the positive electrode connection portion 820 of the stacked body including the current collector 1102 and the current collector 1104 is disposed near the ends of the positive electrode 220 including the current collector 1102 and the positive electrode 220 including the current collector 1104. Therefore, according to the present embodiment, the two positive electrodes 220 are integrated near these ends. As a result, the mass of the battery cell 112 is reduced compared to the case where each of the multiple current collectors is provided with a tab and the tabs of the multiple current collectors are electrically connected by wiring. As a result, a battery cell 112 with a large mass energy density is obtained.

[0347] In this embodiment, before the above-mentioned softening treatment or pressing treatment of the thermoplastic resin is performed, the lead 822 and the sub-lead 824 are used to reinforce the collector 1102 and the collector 1104. This prevents the conductive layer 442 and / or the conductive layer 444 from being broken due to the pressure applied during welding.

[0348] The current collector 1102 may be an example of a welding object, a sheet material, a first sheet material, or a third sheet material. The current collector 1104 may be an example of a welding object, a sheet material, a second sheet material, or a third sheet material. The current collector 1102 and the conductive layer 442 of the current collector 1104 may be an example of a first metal layer. The current collector 1102 and the conductive layer 444 of the current collector 1104 may be an example of a second metal layer. The current collector 1102 and the conductive layer 642 of the current collector 1104 may be an example of a conductive member disposed on the inner wall of the through hole.

[0349] use Fig.12 as well as Fig.13 An example of the plurality of through holes 620 provided in the current collector 1102 will be described. Fig.12 This is an example of a top view of the current collector 1102 . Fig.13 It is an example of a cross-sectional view of the current collector 1102. In addition, the plurality of through holes 620 provided in the current collector 1104 may have the same features as the plurality of through holes 620 provided in the current collector 1102.

[0350] like Fig.12 As shown in the figure, in the present embodiment, the diameter d (e.g., equivalent circle diameter) of each of the plurality of through holes 620 may also be 15 μm to 150 μm. When the diameter d is less than 15 μm, the thermoplastic resin is not easy to flow into the interior of the through hole 620. In addition, the volume of the through hole 620 is small, so the volume expansion coefficient of the welded laminate becomes large. On the other hand, if the diameter d exceeds 150 μm, the strength of the collector 1102 becomes small, and the collector 1102 is easy to break during welding.

[0351] In the present embodiment, the interval (sometimes referred to as pitch) P between two adjacent through holes 620 may also be 30 μm to 250 μm. When the pitch P is less than 30 μm, the strength of the collector 1102 decreases, and the collector 1102 is easily broken during welding. In addition, the resistance of the collector 1102 increases. On the other hand, if the pitch P exceeds 250 μm, the amount of movement of the thermoplastic resin increases, and the volume expansion coefficient of the welded laminate increases.

[0352] The length TL of the current collector 1102 in the extension direction may be greater than the length HL of the region (sometimes referred to as the through hole band) in which the plurality of through holes 620 are formed, and TL and HL may be substantially the same. The length TW in the direction substantially perpendicular to the extension direction of the current collector 1102 (sometimes referred to as the width direction) may be greater than the length HW in the width direction of the through hole band, and TW and HW may be substantially the same.

[0353] In this embodiment, the above-mentioned welding area is arranged inside the through hole band. At least a part of the above-mentioned softening area is arranged inside the through hole band. For example, the above-mentioned adjacent area is arranged inside the through hole band. The above-mentioned softening area can also be arranged inside the through hole band.

[0354] The size of the softened region Rs may also be determined based on the size of the welded region Rw. The size of the softened region Rs is determined, for example, by expressing the ratio of the area Ss of the softened region Rs in the first plane 422 or the second plane 424 of the support layer 420 to the area Sw of the welded region Rw in the first plane 422 or the second plane 424 of the support layer 420 by the following formula (1). Thus, the volume of the through hole 620 existing in the softened region Rs is equal to or greater than the volume of the thermoplastic resin existing in the welded region Rw.

[0355] (Equation 1)

[0356] Ss / Sw≥(1-εw+εout) / εout

[0357] In Formula 1, εw represents the porosity of the plurality of through holes in the weld region Rw. εout represents the porosity of the plurality of through holes in the softening region Rs other than the weld region Rw. εw and εout are porosities at the temperature of the softening process.

[0358] The porosity εw of the plurality of through holes in the weld region Rw may be 10% or more at the softening temperature. The porosity εw at the softening temperature is preferably 20% or more, and more preferably 30% or more.

[0359] like Fig.13 As shown in FIG. 6 , the 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 .

[0360] As described above, the thickness Hd of the conductive layer 642 may be 0 μm to 5 μm. The thickness Hd of the conductive layer 642 is preferably 0.1 μm to 3 μm, and more preferably 0.1 μm to 1 μm.

[0361] As described above, the thickness hr of the support layer 420 may 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.

[0362] As described above, the thickness hm of the conductive layer 442 and the conductive layer 444 may be 0.1 μm to 10 μm. The thickness hm of the conductive layer 442 and the conductive layer 444 is preferably 0.1 μm to 5 μm, and more preferably 0.1 μm to 1 μm.

[0363] Fig.14 An example of a process for producing a stacked structure 760 in which a portion of the positive electrode current collector 222 of each of the plurality of positive electrodes 220 is integrated is shown. Fig.11As described above, according to the present embodiment, first, in S1410, a plurality of positive electrodes 220 are prepared. Next, in S1420, the ends of the positive electrode collectors 222 of the plurality of positive electrodes 220 are stacked. In S1430, the lead 822 and the sub-lead 824 are provided so as to sandwich the ends of the positive electrode collectors 222 on which the lead 822 and the sub-lead 824 are stacked.

[0364] In S1440, energy is applied to the softened region of the stacked positive electrode current collector 222 to soften the thermoplastic resin contained in the support layer 420 of the positive electrode current collector 222. In S1450, the welded region of the stacked positive electrode current collector 222 is pressed to move the softened thermoplastic resin into the through hole 620 of the positive electrode current collector 222. In S1450, a welding current is applied to the welded region of the stacked positive electrode current collector 222 to weld the conductive layer 442 and the conductive layer 444 of the positive electrode current collector 222.

[0365] Fig.15 Schematically showing the association Fig.11 The end of the current collector 1102 and the current collector 1104 in the positive electrode connection part 820 and the cross section of the vicinity of the end are shown. Alternatively, the negative electrode connection part 840 may also have the same structure as the positive electrode connection part 820. Fig.15 As shown, an integrated region, an adjacent region adjacent to the integrated region, and a peripheral region adjacent to the adjacent region are provided near the ends of the current collector 1102 and the current collector 1104 .

[0366] Fig.15 In order to simplify the description, it is depicted that there is a gap between the current collector 1102 and the current collector 1104. However, it should be noted that the current collector 1102 and the current collector 1104 are in contact with each other in reality. Fig.15 In order to simplify the description, the through holes formed in the current collector 1102 and the current collector 1104 are not depicted. Fig.15 In the embodiment described above, for the sake of simplicity, the details of the positive electrode connecting portion 820 are described by taking the case where two current collectors are stacked as an example. However, it should be noted that the number of stacked current collectors is not limited to two.

[0367] According to the association Fig.11In the described embodiment, the welding process is carried out in a state where the ends of the collector 1102 and the collector 1104 and a part near the ends are clamped by the lead 822 and the sub-lead 824. Therefore, the thermoplastic resin extruded from the welding area including the integrated area flows into the adjacent area. As a result, a part of the adjacent area has a raised shape. In the peripheral area, the collector 1102 and the collector 1104 have the same shape as before welding. According to this embodiment, the average value Hp of the thickness of the peripheral area is greater than the average value Hu of the thickness of the integrated area, and is less than the maximum value Hmax of the thickness of the adjacent area. As mentioned above, the average value Hu of the thickness of the integrated area can also be the average value of the thickness of the integrated area near the center of the integrated area.

[0368] The average value of the thickness of the integrated region is determined by averaging the measured values ​​of the three locations. The average value of the thickness of the peripheral region is determined by averaging the measured values ​​of the three locations. Alternatively, the thickness of five locations in each region may be measured, and the average value of the measured values ​​of the three locations excluding the maximum value and the minimum value may be derived as the average value of the thickness of each region. The measurement interval is appropriately set to obtain the above number of measured values.

[0369] In this embodiment, the integrated region has a length of Lu. In the integrated region, for example, at least one of the metal material 1522, the thermoplastic resin material 1524, and the void 1526 exists. The thermoplastic resin material 1524 is disposed inside the metal material 1522. The void 1526 is disposed inside the metal material 1522. More than one resin material 1524 may be disposed inside the metal material 1522, and more than one void 1526 may be disposed. A plurality of resin materials 1524 may be disposed in a dispersed manner inside the metal material 1522, and a plurality of voids 1526 may be disposed in a dispersed manner.

[0370] As described above, in the present embodiment, a plurality of through holes 620 penetrating the current collector 1102 or the current collector 1104 are formed in the welding region between the current collector 1102 and the current collector 1104. The thermoplastic resin material 1524 is derived from, for example, the thermoplastic resin contained in the support layer 420. The voids 1526 are derived from, for example, the through holes 620 formed in the conductive layer 442 and / or the conductive layer 444.

[0371] Metal material 1522, for example, includes the same type of conductive material as the conductive material (e.g., metal) included in conductive layer 442 and / or conductive layer 444. It may also include the same type of conductive material (e.g., metal) as the main component of conductive layer 442 and / or conductive layer 444. Metal material 1522 may also include the same type of conductive material as the conductive material (e.g., metal) included in conductive layer 642. Metal material 1522 may also include the same type of conductive material (e.g., metal) as the main component of conductive layer 642. Metal material 1522 may also include the same type of conductive material as the conductive material (e.g., metal) included in lead 822. Metal material 1522 may also include the same type of conductive material (e.g., metal) as the main component of lead 822.

[0372] In the present embodiment, the adjacent region is, for example, a region whose distance from the end of the integrated region is greater than 0 and less than La. As described above, the welding region is disposed inside the through-hole band of the current collector, and a portion of the thermoplastic resin extruded from the welding region during the welding process flows into the through-hole disposed in the adjacent region. Therefore, in the adjacent region, there may be through-holes, through-holes partially filled with thermoplastic resin, and / or through-holes completely filled with thermoplastic resin.

[0373] In the present embodiment, the peripheral region is, for example, a region at a distance of more than La and less than Lp from the end of the integrated region. The end of the integrated region is, for example, a position where the thickness is 1.1 times the average value Hu of the thickness of the integrated region when the cross section of the positive electrode connecting portion 820 including the integrated region is observed using SEM. When there are multiple positions having a thickness of 1.1 times the average value Hu of the thickness of the integrated region, the end of the integrated region may also be the position closest to the center of the integrated region among the multiple positions.

[0374] As described above, the peripheral region is a region whose shape hardly changes before and after the welding process. In the present embodiment, a portion of the thermoplastic resin present in the integrated region before welding moves to the adjacent region during welding. Therefore, the resin content in the integrated region (a) after welding is less than the resin content in the peripheral region of the collector 1102 or the collector 1104 (b) after welding. The resin content in the integrated region (a) after welding may also be 0.1 to 0.7 times the resin content in the peripheral region (b) after welding.

[0375] As the resin content in the peripheral region, it is preferred to use the resin content at a position more than 5 mm away from the end of the integrated region. In addition, when the resin content in the peripheral region is different between the multiple collectors stacked in the positive electrode connecting portion 820, the resin content in the integrated region after (a) welding can also be compared with the resin content of the collector with the largest resin content in the peripheral region among the multiple collectors stacked (b).

[0376] La may be 1 mm, 5 mm, or 10 mm. Lp is a value larger than La, and may be 1 mm, 5 mm, or 10 mm.

[0377] In the present embodiment, the maximum value Hmax of the thickness of the adjacent region is, for example, 1.5 times or less of the average value Hp of the thickness of the surrounding region. The maximum value Hmax of the thickness of the adjacent region is preferably 1.3 times or less of the average value Hp of the thickness of the surrounding region, and more preferably 1.1 times or less of the average value Hp of the thickness of the surrounding region.

[0378] In other embodiments, the thickness at a position 100 μm away from the end of the integrated region may be less than 1.5 times the thickness at a position 1 mm away from the end of the integrated region. The thickness at a position 100 μm away from the end of the integrated region may be less than 1.3 times the thickness at a position 1 mm away from the end of the integrated region, or less than 1.1 times the thickness at a position 1 mm away from the end of the integrated region.

[0379] According to this embodiment, a part of the thermoplastic resin present in the integrated region before welding moves to the adjacent region during welding. Therefore, before and after the welding process, a part of the adjacent region is more raised than the surrounding region. The height Hr of the raised portion on one side may be less than 25% of Hp, less than 15%, or less than 5%. The ratio of Hr to Hp may also be 0.1 to 20%, preferably 1 to 15%, and more preferably 2 to 10%.

[0380] When the ratio of Hr to Hp is less than 0.1%, the softening of the thermoplastic resin of the support layer 420 is insufficient, and welding may also be insufficient. On the other hand, when the ratio of Hr to Hp exceeds 25%, welding peeling, breakage of the foil, partial cracks in the conductive layer, etc. may be caused due to local expansion of the collector. In addition, as a result, the performance of the battery may be reduced.

[0381] According to the present embodiment, a through hole 620 is formed in the softening region and / or the welding region. Therefore, compared with the case where the through hole 620 is not formed in the softening region and / or the welding region, the ratio of Hr to Hp becomes smaller. As a result, welding peeling, foil breakage, partial cracks in the conductive layer, etc. can be suppressed. In addition, as a result, the performance of the battery can be improved. In addition, a relatively small ratio of Hr to Hp may indicate that a through hole 620 is formed in the softening region and / or the welding region. Similarly, a resin content in the integrated region after (a) welding is less than the resin content in the peripheral region after (b) welding, which may indicate that a through hole 620 is formed in the softening region and / or the welding region.

[0382] The current collector 1102 may be an example of a current collector included in the first electrode or the second electrode. The current collector 1104 may be an example of a current collector included in the first electrode or the second electrode. The stacked multiple current collectors may be an example of multiple sheet materials. The current collector having the highest resin content in the peripheral region among the stacked multiple current collectors may be an example of the third sheet material. The resin content in the integrated region after welding may be an example of the first ratio. The resin content in the peripheral region after welding may be an example of the second ratio.

[0383] Example

[0384] Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to the following Examples.

[0385] (Example 1)

[0386] The current collector to be welded was produced by the following process. In addition, a laminate was produced by partially welding five current collectors.

[0387] (Production of Current Collector)

[0388] First, a polyimide film (Kapton, manufactured by DuPont Toray, thickness 5 μm) was prepared as a supporting layer for the current collector. Next, a nickel layer and a copper layer were formed on both sides of the polyimide film by chemical plating. The nickel layer was formed between the polyimide film and the copper layer. The thickness of the nickel layer was 0.1 μm. The thickness of the copper layer was 1 μm.

[0389] Next, a through hole band having a plurality of through holes was formed in a portion of the polyimide film. The cross-sectional shape of each through hole was circular, and the average diameter of each through hole was 50 μm. In addition, the pitch of the through holes was 100 μm.

[0390] Next, a copper layer was formed on the inner wall of the through hole by chemical plating. The thickness of the copper layer was 1 μm. The average diameter of the space of the through hole after the copper layer was formed was 48 μm.

[0391] Five current collectors were produced by cutting a polyimide film having through-hole bands and a copper layer in the through-holes. The polyimide film was cut so that each current collector had an L-shaped plane shape with a rectangular current collector portion of 37 mm × 32 mm and a square pole ear portion of 10 mm × 10 mm. In each current collector, the polyimide film was cut so that one side of the pole ear portion was connected to one of the long sides of the current collector portion. In each current collector, the polyimide film was cut so that the other side of the pole ear portion and one of the short sides of the current collector portion were arranged on the same straight line. The other side of the pole ear portion is the side connected to the side connected to one of the long sides of the current collector portion.

[0392] As described above, the TL of the pole lug portion of each current collector is 10 mm, and the TW is 10 mm. A through hole band is formed in the pole lug portion of each current collector, and the HL of each current collector is 7 mm, and the HW is 10 mm. The distance from the side of the pole lug portion that is in contact with the current collecting portion to the through hole band is 1 mm. The distance from the side of the pole lug portion that is opposite to the side that is in contact with the current collecting portion to the through hole band is 2 mm.

[0393] (Production of Laminated Body)

[0394] Five current collectors are stacked in such a way that the positions of the through-hole bands of the five current collectors are roughly consistent. The 3.0 mm×5.0 mm area inside the through-hole band of the current collector is set as the welding area. The five stacked current collectors are arranged in the working area of ​​the welding device 1120 in a state where the five stacked current collectors are sandwiched between the Ni-plated Cu lead and the Ni-plated Cu sub-lead. The thickness of the sub-lead is 70 μm, and the area of ​​the sub-lead is 10 mm×30 mm.

[0395] As the welding device 1120, a lithium-ion battery laminated foil welding device manufactured by Nag System Co., Ltd. was used. After the welding head 1130 of the welding device 1120 was brought into contact with the welding area, power was supplied to the heating part 1134 to heat the welding area. Thereafter, power was supplied to the welding part 1136 to weld the welding area. The power supply conditions during heating and welding were current 1.0 to 2.5 kA, voltage 1.5 to 2.5 V, and application time 10 to 70 ms.

[0396] (Example 2)

[0397] The number of layers of the collectors, the thickness of the sub-leads, the diameter of the through holes, the pitch of the through holes, the thickness of each single side of the conductive layer formed on both sides of the support layer, and the thickness of the copper layer formed on the inner surface of the through holes were changed to produce a laminated body by the same process as in Example 1. Details of the production conditions of the laminated body are shown in Table 1.

[0398] (Comparative Example 1)

[0399] Five current collectors were prepared by the same process as in Example 1. Five current collectors were welded by the same process as in Example 1 except that a high-power ultrasonic metal bonding machine manufactured by Seidensha Electronics Industry Co., Ltd. was used and the heating process before the welding process was omitted. The conditions for ultrasonic welding performed by the high-power ultrasonic metal bonding machine were power supply 600kW, bonding frequency 19.15kHz, pressure value 623N, bonding depth 0.1mm, bonding time 0.5-1s, amplitude 80%, soft start 100ms, power 100W, speed 300mm / s, no cooling, and frequency offset 20Hz. In addition, the current value was about 5-19A.

[0400] (Comparative Example 2)

[0401] A laminate was produced by the same process as in Example 1 except that no through-holes were formed in the polyimide film. Table 1 shows the details of the production conditions of the laminate.

[0402] (Comparative Example 3)

[0403] A laminate was produced by the same process as in Example 1 except that no sub-leads were used. Table 1 shows the details of the production conditions of the laminate.

[0404] (Comparative Example 4)

[0405] The thickness of the sub-lead, the diameter of the through-hole, and the pitch of the through-holes were changed, and a laminate was produced by the same process as in Example 1. The details of the production conditions of the laminate are shown in Table 1.

[0406] (Comparative Example 5)

[0407] The thickness of the sub-lead, the diameter of the through-hole, and the pitch of the through-holes were changed, and a laminate was produced by the same process as in Example 1. The details of the production conditions of the laminate are shown in Table 1.

[0408] [Table 1]

[0409]

[0410] (evaluate)

[0411] A tensile test of the current collector, a welding confirmation test of the laminate, and a resistance measurement test of the laminate were performed on each of Examples 1 and 2 and Comparative Examples 1 to 5. The results of each test are shown in Table 2.

[0412] The tensile test of the current collector was performed by the same procedure as the tensile test of the sample described in relation to the degree of resistance to fracture of the current collector 400. The case where the tensile strength was 450 MPa or more was marked as ◎, the case where the tensile strength was 360 MPa or more was marked as 0, and the other cases were marked as ×.

[0413] The weld confirmation test of the laminated body was conducted by peeling the leads from the welded laminated body and then measuring the force required to peel the current collectors one by one from the welded laminated body using a spring balance. Specifically, whether welding with sufficient strength was possible was confirmed by the following process.

[0414] First, the lead arranged on one side of the laminate after welding is peeled off. Next, the other side of the laminate is bonded to a flat surface arranged approximately horizontally using an adhesive. As a result, the laminate after welding is firmly fixed to the flat surface. Next, a spring balance is installed at the front end of one end of the current collector arranged at the top among the m (m is an integer greater than 2) current collectors constituting the laminate after welding. By pulling the spring balance in a manner that makes the pulling direction become a substantially vertical direction, the current collector arranged at the top is peeled off from the remaining current collectors. Repeat the above process to peel off the current collectors one by one. When the difference between the measured value of the first current collector and the measured value of the nth (n is an integer greater than 2 and less than m) current collector is 50% or more, it is considered unqualified. When the above difference is less than 50%, it is considered qualified. In Table 2, 0 represents qualified and × represents unqualified.

[0415] The resistance value measurement test is implemented by measuring the resistance value of each of the multiple collectors contained in the stacked body in a state where the leads are installed in the stacked body. First, the sample of the welded stacked body is cut into a size of 10 mm × 40 mm in a manner that includes the entire lug portion of each collector. As shown in Table 1, in each embodiment and each comparative example, the stacked body includes 5 or 15 collectors. Therefore, according to the following process, the resistance value is measured for each collector. The resistance value of each collector contained in the sample is measured using a resistance measuring machine. One of a pair of measuring electrodes is brought into contact with the lead, and one of a pair of measuring electrodes is brought into contact with the conductive layer (metal foil) of the collector to be measured. A voltage is applied to the measuring electrodes to measure the resistance value of each collector.

[0416] Next, statistical processing of the resistance values ​​of each of the multiple current collectors constituting the stack was implemented. Specifically, first, the central value of the resistance values ​​of each of the multiple current collectors was calculated. Next, the resistance values ​​of the current collectors other than the current collector representing the above-mentioned central value (sometimes referred to as other current collectors) were compared with the central value. In the case where the other current collectors mentioned above include a current collector whose difference between the resistance value of the current collector and the above-mentioned central value is greater than 50% of the central value, the result of the measurement test of the stack is deemed to be unqualified. In the case where the other current collectors mentioned above do not include a current collector whose difference between the resistance value of the current collector and the above-mentioned central value is greater than 50% of the central value, the result of the measurement test of the stack is deemed to be qualified. In Table 2, 0 represents qualified and × represents unqualified.

[0417] [Table 2]

[0418] No Tensile test Welding confirmation test Uneven resistance Example 1 ◎ ○ ○ Example 2 ○ ○ ○ Comparative Example 1 ◎ × × Comparative Example 2 ◎ ○ × Comparative Example 3 ◎ × × Comparative Example 4 × × ○ Comparative Example 5 ◎ 〇 ×

[0419] (Cut section of the integrated area)

[0420] Fig.16 An SEM image of the integrated region of the laminate in Example 1 is shown. Fig.16 FIG. 4 shows an SEM image of the laminate near the center of the weld region. Fig.16 As shown, resin and voids exist in the integrated region of the laminate. In the laminate of Example 1, the resin content in the integrated region is about 10%. In the laminate of Example 1, the void ratio in the integrated region is about 3 to 5%.

[0421] The present invention has been described above using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. According to the description of the claims, the method to which such changes or improvements are made is also included in the technical scope of the present invention.

[0422] It should be noted that the execution order of each process such as actions, processes, steps and stages in the devices, systems, programs and methods shown in the claims, specifications and drawings is not specifically specified as "before", "prior to", etc., and can be implemented in any order as long as the output of the previous process is not used in the subsequent process. Regarding the action flow in the claims, specifications and drawings, for convenience, "first," "next," etc. are used to explain, but it does not mean that it must be implemented in this order.

[0423] This application specification discloses, for example, the following matters.

[0424] (Item 1)

[0425] A method for producing an electrode, comprising the following stages:

[0426] The stage of preparing the current collector;

[0427] forming an active material layer containing an organic compound as an active material on at least one side of the current collector; and

[0428] In the step of fixing the active material layer and the current collector,

[0429] The current collector comprises: a conductive layer containing a conductive material and a support layer supporting the conductive layer.

[0430] The electrical conductivity of the supporting layer is lower than that of the conductive layer.

[0431] The density of the supporting layer is lower than that of the conductive layer.

[0432] The step of fixing the active material layer and the current collector includes a step of applying pressure to the stacked active material layer and the current collector, wherein the pressure is set or adjusted so that

[0433] (i) the rate of change in the resistance of the current collector before and after the application of pressure to the active material layer and the current collector is within 50%; or

[0434] (ii) The absolute value of the difference in resistance of the current collector before and after the pressure is applied to the active material layer and the current collector is less than 1 [Ω].

[0435] (Item 2)

[0436] A method for producing an electrode, comprising the following stages:

[0437] The stage of preparing the current collector;

[0438] forming an active material layer containing an organic compound as an active material on at least one side of the current collector; and

[0439] In the step of fixing the active material layer and the current collector,

[0440] The current collector comprises: a conductive layer containing a conductive material and a support layer supporting the conductive layer.

[0441] The electrical conductivity of the supporting layer is lower than that of the conductive layer.

[0442] The density of the supporting layer is lower than that of the conductive layer.

[0443] The stage of fixing the above-mentioned active material layer and the above-mentioned collector includes the stage of applying pressure to the stacked above-mentioned active material layer and the above-mentioned collector, and the above-mentioned pressure is set or adjusted so that the value obtained by subtracting (ii) the value of the first voltage measured by applying current to the above-mentioned conductive layer of the above-mentioned collector before the pressure is applied from the value of the second voltage measured by applying current to the above-mentioned conductive layer of the above-mentioned collector after the pressure is applied is less than 100mV.

[0444] (Item 3)

[0445] A method for producing an electrode, comprising the following stages:

[0446] The stage of preparing the current collector;

[0447] forming an active material layer containing an organic compound as an active material on at least one side of the current collector; and

[0448] In the step of fixing the active material layer and the current collector,

[0449] The current collector comprises: a conductive layer containing a conductive material and a support layer supporting the conductive layer.

[0450] The electrical conductivity of the supporting layer is lower than that of the conductive layer.

[0451] The density of the supporting layer is lower than that of the conductive layer.

[0452] The step of fixing the active material layer and the current collector includes a step of applying pressure to the stacked active material layer and the current collector, and the pressure is set or adjusted so that the porosity of the active material layer after the pressure is applied becomes 25 to 40%.

[0453] (Item 4)

[0454] In the method described in any one of items 1 to 3, the step of applying the pressure includes applying pressure to the stacked active material layer and the current collector using a roller press so that the linear pressure becomes 1.0 kgf / cm to 200 kgf / cm.

[0455] (Item 5)

[0456] In the method according to any one of items 1 to 3, the support layer is a sheet-like resin material.

[0457] (Item 6)

[0458] In the method according to any one of items 1 to 3, the conductive layer includes aluminum in a layer or foil form, and the thickness of the aluminum in a layer or foil form is 0.05 μm to 5 μm.

[0459] (Item 7)

[0460] A method for producing an electrode structure has the following stages:

[0461] The stage of preparing positive and negative electrodes;

[0462] the stage of preparing the diaphragm; and

[0463] In the stage of sequentially stacking the positive electrode, the separator and the negative electrode,

[0464] The step of preparing the positive electrode and the negative electrode includes a step of manufacturing at least one of the positive electrode and the negative electrode by the method described in any one of items 1 to 3.

[0465] (Item 8)

[0466] An electrode is an electrode comprising a collector and an active material layer disposed on at least one side of the collector and containing an organic compound as an active material, wherein the collector comprises: a conductive layer containing a conductive material and a supporting layer supporting the conductive layer, the thickness of the conductive layer is 0.05 μm to 5 μm, the conductivity of the supporting layer is less than the conductivity of the conductive layer, the density of the supporting layer is less than the density of the conductive layer, and the resistance of the collector is 0.01 mΩ to 1 Ω.

[0467] (Item 9)

[0468] In the electrode according to item 8, the porosity of the active material layer is 25 to 40%.

[0469] (Item 10)

[0470] In the electrode according to item 8 or 9, the conductive layer is an aluminum foil, and the support layer is a sheet-like resin material.

[0471] (Item 11)

[0472] In the electrode according to item 8 or 9, the current collector is formed with a plurality of through holes, and each of the plurality of through holes has an equivalent circular diameter of 15 μm to 150 μm.

[0473] (Item 12)

[0474] In the electrode according to item 11, a ratio of a total area of ​​the plurality of through holes in the one surface of the current collector to an outer surface area of ​​the one surface of the current collector is 30% or more.

[0475] (Item 13)

[0476] The electrode according to item 11 further includes an internal conductive layer, which is disposed on inner walls of at least a part of the plurality of through holes and contains a conductive material.

[0477] (Item 14)

[0478] In the laminated body according to Item 13, the internal conductive layer includes three or more layers having different main components.

[0479] (Item 15)

[0480] An electrode structure having

[0481] More than one positive electrode,

[0482] One or more negative electrodes, and

[0483] one or more separators disposed between each of the one or more positive electrodes and each of the one or more negative electrodes,

[0484] At least one of the one or more positive electrodes and the one or more negative electrodes is the electrode according to any one of item 8 or item 9.

[0485] (Item 16)

[0486] In the electrode structure described in item 15, the separator contains a polymer solid electrolyte.

[0487] (Item 17)

[0488] A battery comprising the electrode structure according to item 15 and a case for housing the electrode structure.

[0489] (Item 18)

[0490] The battery according to item 17 further comprises: at least one of a positive electrode connecting portion electrically connected to the one or more positive electrodes and a negative electrode connecting portion electrically connected to the one or more negative electrodes;

[0491] The positive electrode connecting portion includes a positive electrode supporting portion, and the positive electrode supporting portion sandwiches and supports a portion of the one or more positive electrodes.

[0492] The negative electrode connecting portion includes a negative electrode supporting portion that sandwiches and supports a portion of the one or more negative electrodes.

[0493] (Item 19)

[0494] A flying object having:

[0495] The battery described in item 17; and

[0496] The propulsion generating device generates propulsion using the electric energy stored in the battery.

[0497] Description of Reference Numerals

[0498] 100: flying object; 110: storage battery; 112: storage battery core; 120: power control circuit; 130: motor; 140: propeller; 150: sensor; 160: control device; 212: positive electrode shell; 214: negative electrode shell; 216: sealant; 218: metal spring; 220: positive electrode; 222: positive electrode collector; 224: positive electrode active material layer; 230: separator; 240: negative electrode; 242: negative electrode collector; 244: negative electrode active material layer; 260: structure; 350: electrolyte; 400: collector; 420: support layer; 422: first plane; 424: second plane; 426: side surface; 442: conductive layer; 444: conductive layer; 5 00: collector; 522: through hole; 546: conductive material; 600: collector; 620: through hole; 622: inner wall; 642: conductive layer; 760: laminated structure; 820: positive electrode connection; 822: lead; 824: sub-lead; 840: negative electrode connection; 842: lead; 844: sub-lead; 1102: collector; 1104: collector; 1120: welding device; 1130: welding head; 1132: position adjustment part; 1134: heating part; 1136: welding part; 1140: power supply for heating; 1150: power supply for welding; 1160: controller; 1522: metal material; 1524: resin material; 1526: gap.

Claims

1. A laminate, A plurality of stacked sheet materials are provided. Each of the plurality of sheet materials has: a support layer comprising a thermoplastic resin material; and The first metal layer and the second metal layer are formed on both sides of the support layer. In a part of the plurality of sheet materials, the plurality of first metal layers and the plurality of second metal layers included in the plurality of sheet materials are integrated.

2. The laminate according to claim 1, wherein The ratio of the volume of the resin contained in the integrated region, which is a region where the plurality of first metal layers and the plurality of second metal layers are integrated, to the volume of the metal contained in the integrated region is 5 to 50%.

3. The laminate according to claim 2, wherein: The plurality of sheet materials include a first sheet material disposed on the outermost side of one side of the plurality of sheet materials, The laminate further comprises a conductive first supporting member supporting the first sheet material. The main component of the first supporting member is different from the main component of the plurality of first metal layers and the main component of the plurality of second metal layers. In the integrated region, a ratio of the volume of the thermoplastic resin material to the total volume of the metal of the same type as the main component of the plurality of first metal layers and the volume of the metal of the same type as the main component of the plurality of second metal layers is 5 to 50%.

4. The laminate according to claim 1, wherein A ratio of the volume of voids included in a region where the plurality of first metal layers and the plurality of second metal layers are integrated, ie, an integrated region, to the volume of metal included in the integrated region is 10% or less.

5. The laminate according to any one of claims 1 to 4, wherein The plurality of sheet materials have: a first sheet material disposed at the outermost side of one side of the plurality of sheet materials; and a second sheet material disposed on the outermost side of the other side of the plurality of sheet materials, The laminate further comprises: an electrically conductive first support member supporting said first sheet material; and A conductive or non-conductive second support member supports the second sheet material.

6. The laminate according to any one of claims 1 to 5, wherein Each of the plurality of sheet materials has a region in which a plurality of through holes penetrating the respective sheet materials are formed near a region where the plurality of first metal layers and the plurality of second metal layers are integrated, that is, an integrated region.

7. The laminate according to claim 6, wherein: The invention further includes a conductive layer disposed on inner walls of at least a portion of the plurality of through holes.

8. The laminate according to claim 7, wherein: The conductive layer includes three or more layers having different main components.

9. The laminate according to any one of claims 6 to 8, wherein The thermoplastic resin material is disposed inside at least a portion of the plurality of through holes.

10. The laminate according to any one of claims 6 to 9, wherein The equivalent circle diameter of the plurality of through holes is 15 μm to 150 μm, The interval between two adjacent through holes among the plurality of through holes is 30 μm to 250 μm.

11. The laminate according to any one of claims 1 to 10, wherein In each of the plurality of sheet materials, (a) the first ratio is smaller than (b) the second ratio, wherein the first ratio (a) is the ratio of the volume of the thermoplastic resin material contained in the region where the plurality of first metal layers and the plurality of second metal layers are integrated, i.e., the integrated region, to the volume of the metal contained in the integrated region, and the second ratio (b) is the ratio of the volume of the thermoplastic resin material contained in the third sheet material contained in the plurality of sheet materials at a position more than 5 mm away from the end of the integrated region to the volume of the metal, The third sheet material is a sheet material having the largest second ratio among the plurality of sheet materials.

12. The laminate according to claim 11, wherein The value of the first ratio is 0.1 to 0.7 times the value of the second ratio.

13. An electrode structure comprising: A first electrode and a second electrode; a third electrode and a fourth electrode; as well as a first diaphragm, a second diaphragm and a third diaphragm, The first electrode, the first separator, the third electrode, the second separator, the second electrode, the third separator, and the fourth electrode are sequentially stacked. 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 comprises: a support layer comprising a thermoplastic resin material; as well as The first metal layer and the second metal layer are formed on both sides of the support layer. 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 near the ends of the first electrode and the second electrode.

14. The electrode structure according to claim 13, wherein: (a) the first ratio is smaller than (b) the second ratio, wherein the first ratio (a) is the ratio of the volume of the thermoplastic resin material contained in the region where the first metal layer and the second metal layer are integrated, i.e., the integrated region, to the volume of the metal contained in the integrated region, and the second ratio (b) is the ratio of the volume of the thermoplastic resin material contained in the first electrode or the second electrode at a position at least 5 mm away from the end of the integrated region to the volume of the metal, The second ratio is the ratio of the current collector of the first electrode and the current collector of the second electrode, the current collector having the larger ratio.

15. A battery comprising: The electrode structure according to claim 14; and A casing for housing the electrode structure.

16. A flying object having: The battery of claim 15; and The propulsion generating device generates propulsion using the electric energy stored in the battery.

17. A method of producing a laminate, comprising: In a preparation stage, a welding object is prepared, wherein the welding object includes a support layer including a thermoplastic resin material and a first metal layer and a second metal layer formed on both sides of the support layer; A stacking stage, stacking a plurality of the welding objects; In a softening stage, energy is applied to a softening region disposed at a portion of the plurality of welding objects to soften the resin material in the softening region; In a pressing stage, pressing is performed on a welding area disposed at least in part of the softened area; as well as In the welding stage, current and / or voltage are applied to the pressed welding area to weld the first metal layer and the second metal layer of the plurality of welding objects. The first metal layer and the second metal layer of each of the plurality of welding objects are electrically connected, A plurality of through holes penetrating the support layer, the first metal layer, and the second metal layer are formed in at least a portion of the softened region of each of the plurality of welding objects.

18. The method for producing a laminated body according to claim 17, wherein A conductive member that electrically connects the first metal layer and the second metal layer is disposed on an inner wall of at least a portion of the plurality of through holes.

19. The method for producing a laminated body according to claim 18, wherein The conductive member comprises a plurality of layers, The plurality of layers are each composed of a material different from one another.

20. The method for producing a laminated body according to any one of claims 17 to 19, wherein A plurality of through holes penetrating the support layer, the first metal layer, and the second metal layer are formed in the welding region of each of the plurality of welding objects. A plurality of through holes penetrating the first metal layer and the second metal layer are formed in a region of the softened region of each of the plurality of welding objects adjacent to the welding region.

21. The method for producing a laminated body according to any one of claims 17 to 20, wherein The pressing phase includes the following phases: A step of applying pressure to the stacked plurality of welding objects so that the softened resin material flows into the interior of at least a portion of the through-holes; as well as The first metal layer and the second metal layer of each of the plurality of welding objects are brought close to each other to a distance enabling welding.

22. The method for producing a laminate according to claim 21, wherein A conductive member for electrically connecting the first metal layer and the second metal layer is disposed on the inner wall of at least a portion of the plurality of through holes. The stage of applying pressure to the plurality of welding objects includes the following stages: A pressure is applied to the stacked plurality of welding targets so that the softened resin material breaks the conductive member provided on the inner wall of at least a portion of the through-hole and flows into the at least a portion of the through-hole.

23. The method for producing a laminated body according to any one of claims 17 to 22, wherein The welding stage includes a stage of applying a current and / or a voltage to the welding region while further pressing the welding region pressed in the pressing stage.

24. The method for producing a laminated body according to any one of claims 17 to 23, wherein The method further comprises a supporting stage in which the softened regions or the welded regions of the plurality of welding objects are sandwiched by using a conductive first supporting member and a conductive or non-conductive second supporting member. The supporting phase is carried out before the softening phase or the pressing phase.

25. A method for producing an electrode structure, comprising: A stage of preparing a first electrode and a second electrode; A stage of preparing a third electrode and a fourth electrode; A stage of preparing a first diaphragm, a second diaphragm and a third diaphragm; A step of sequentially stacking the first electrode, the first diaphragm, the third electrode, the second diaphragm, the second electrode, the third diaphragm, and the fourth electrode; and In the step of welding the first electrode and a part of the second electrode, The first electrode and the second electrode each include: a current collector; and an active material layer disposed on at least one side of the current collector, The current collector has: a support layer comprising a thermoplastic resin material; and The first metal layer and the second metal layer are formed on both sides of the support layer. The first metal layer and the second metal layer are electrically connected, A plurality of through holes penetrating the support layer, the first metal layer, and the second metal layer are formed in at least a portion of the softened region disposed in a portion of the current collector. The stage of welding the first electrode and a portion of the second electrode comprises: A step of laminating the current collector of the first electrode and the current collector of the second electrode; In a softening stage, energy is applied to the softened region of the current collector to soften the resin material in the softened region; In a pressing stage, pressing is performed on a welding area disposed at least in part of the softened area; and In the welding stage, current and / or voltage are applied to the pressed welding region to weld the first metal layer and the second metal layer of the current collector of the first electrode and the second electrode.

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