Laminated battery and manufacturing method for laminated battery

Abstract

To provide a laminated battery that achieves both improvement of structural efficiency and suppression of cutting of a current collecting foil, and a manufacturing method for such a laminated battery.SOLUTION: In a laminated battery 10 of the present disclosure, a current collecting terminal 120 has one slit part 120a in a part of a surface facing an electrode laminated body 110; all of a plurality of current collecting foils 111 are collected to form a current collecting foil portion 111a; and the electrode laminated body is electrically connected to the current collecting terminal via the plurality of current collecting foils by inserting and bonding the current collecting foil portion to the slit part. A method of the present disclosure for manufacturing the laminated battery includes steps of: inserting the current collecting foil portion into the slit part of the current collecting terminal; disposing a resistance welding electrode 20 on both sides of the current collecting terminal so as to sandwich the slit part; applying electricity to the resistance welding electrode while pressing the current collecting terminal with the resistance welding electrode to resistance-weld the current collecting foil in the slit part; and housing the electrode laminated body with the current collecting terminal and an exterior body 130.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a stacked battery and a method for manufacturing the stacked battery. [Background technology]

[0002] 2. Description of the Related Art A laminated battery is known that includes an electrode stack, current collecting terminals, and an exterior housing that houses the electrode stack together with the current collecting terminals.

[0003] For example, Patent Document 1 discloses a secondary battery in which a current collector (current collector foil) is joined to the surface of the lid terminal (current collector terminal) facing the power generating element (electrode laminate) in the above-described stacked battery, thereby electrically connecting the current collector terminal and the lid terminal. In this case, Patent Document 1 particularly discloses that structural efficiency can be improved by electrically connecting multiple current collectors to the lid terminal in a curved state.

[0004] Patent Document 1 also discloses a secondary battery having at least one current collector, the inner surface of the lid terminal having at least one slit portion, and the current collector being disposed in the slit portion, thereby electrically connecting the current collector and the lid terminal. In this case, Patent Document 1 discloses that, particularly from the viewpoint of improving structural efficiency, the fewer the number of current collectors disposed in one slit portion, the better, and that a configuration in which one current collector is disposed in one slit portion is optimal.

[0005] Furthermore, Patent Document 1 discloses that by integrating each component with a resin provided in the exterior part (exterior body), it is possible to prevent the current collector from being cut by movement of the power generating element due to an external impact. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-084066 Summary of the Invention [Problem to be solved by the invention]

[0007] When joining the current collector foil and the current collector terminal, it is desirable to be able to improve structural efficiency while also preventing breakage of the current collector foil.

[0008] An object of the present disclosure is to provide a stacked battery that achieves both improved structural efficiency and suppressed breakage of current collecting foils, and a method for manufacturing such a stacked battery. [Means for solving the problem]

[0009] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> an electrode stack; current collecting terminals, and an exterior housing that houses the electrode stack together with the current collecting terminal; A stacked battery having: A plurality of current collecting foils extend from the end faces of the electrode stack, the current collecting terminal has one slit portion on a part of the surface facing the electrode stack, and all of the plurality of current collecting foils are collected to form a foil collecting portion, and the foil collecting portion is inserted into and joined to the slit portion, thereby electrically connecting the electrode stack to the current collecting terminal via the plurality of current collecting foils. Stacked battery. <Aspect 2> 2. The stacked battery according to claim 1, wherein the depth of the slit portion is 30% or more of the thickness of the current collector terminal. <Aspect 3> A method for producing the stacked battery according to aspect 1 or 2, comprising the steps of: providing the electrode stack and the current collecting terminal; inserting the foil collecting portion into the slit portion of the current collecting terminal; Resistance welding electrodes are disposed on both sides of the current collecting terminal so as to sandwich the slit portion. pressing the current collecting terminal with the resistance welding electrode while passing current through the resistance welding electrode to resistance-weld the current collecting foil within the slit portion; and The electrode stack is housed in the collector terminal and the exterior body. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a stacked battery that achieves both improved structural efficiency and suppressed breakage of the current collecting foil, and a method for manufacturing such a stacked battery. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of a stacked battery according to the present disclosure. [Figure 2] FIG. 2 is a schematic diagram illustrating the method for manufacturing a stacked battery according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure. Furthermore, the dimensional relationships in the drawings do not reflect the actual dimensional relationships.

[0013] 《Stacked battery》 As illustrated in Fig. 1, a laminated battery 10 of the present disclosure includes an electrode stack 110, a current collecting terminal 120, and an exterior body 130 that houses the electrode stack together with the current collecting terminal. In the laminated battery of the present disclosure, multiple current collecting foils 111 extend from an end face of the electrode stack. In the laminated battery of the present disclosure, the current collecting terminal has a single slit portion 120a in a portion of the surface facing the electrode stack, and all of the multiple current collecting foils are collected to form a foil collecting portion 111a. The foil collecting portion is inserted into and joined to the slit portion, thereby electrically connecting the electrode stack to the current collecting terminal via the multiple current collecting foils.

[0014] The present inventors have found that, as illustrated in Fig. 1, the current collector foil 111 as the foil collecting portion 111a is joined within the slit portion 120a of the current collector terminal 120, thereby shortening the distance between the electrode stack 110 and the current collector terminal 120 and thereby improving the structural efficiency of the battery. Furthermore, the present inventors have found that, as illustrated in Fig. 1, by collecting all of the multiple current collector foils 111, cutting of the current collector foils 111 can be suppressed.

[0015] The laminated battery of the present disclosure may be, for example, a lithium-ion secondary battery. Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. It is particularly preferred that the battery be used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery of the present disclosure may also be used as a power source for mobile objects other than vehicles (for example, trains, ships, and aircraft), or as a power source for electrical appliances such as information processing devices.

[0016] The elements that make up the stacked battery 10 of the present disclosure will be described below.

[0017] <Electrode laminate> 1, a laminated battery 10 of the present disclosure has an electrode stack 110. The electrode stack functions as the power generating element of the battery.

[0018] In the electrode stack 110, a plurality of current collecting foils 111 extend from the end face of the electrode stack 110. All of the plurality of current collecting foils are gathered together to form a foil collecting portion 111a.

[0019] The electrode stack has a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer in this order. The electrode stack may be formed by stacking multiple stacked battery units 100, each having a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer in this order. In this case, the multiple current collector foils 111 forming the foil collecting portion 111a may be positive electrode current collector layers or negative electrode current collector layers. The positive electrode current collector layer may be shared between the stacked battery units.

[0020] There is no particular limitation on the number of current collector foils 111 extending from the end face of the electrode stack 110. The fewer this number, the smaller the space required to collect multiple current collector foils 111, and therefore the more efficient the battery structure. The greater this number, the stronger the current collector foils 111 become, and so breakage of the current collector foils 111 can be effectively prevented.

[0021] The length, thickness, etc. of the current collecting foil 111 extending from the end face of the electrode laminate 110 are not particularly limited, and can be set appropriately taking into consideration, for example, the structural efficiency of the battery, the strength of the current collecting foil, and the ease of inserting and joining the foil collecting portion 111a into the slit portion 120a.

[0022] The thickness, shape, size, etc. of the electrode stack 110 are not particularly limited and can be set appropriately according to the intended use of the stacked battery, etc.

[0023] The number of stacked battery units 100 is not particularly limited and can be set appropriately according to the application of the stacked battery, etc.

[0024] Hereinafter, each of the components that can constitute the electrode stack according to the present disclosure will be described.

[0025] To facilitate understanding of the present disclosure, the components of an electrode stack of a lithium-ion secondary battery, which is a solid-state battery, will be described as an example. However, the stacked battery of the present disclosure is not limited to a lithium-ion secondary battery. In the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as an electrolyte. Therefore, a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as the electrolyte. Furthermore, the solid-state battery of the present disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as the electrolyte.

[0026] (Positive electrode current collector layer) The conductive material used for the positive electrode current collector layer is not particularly limited, and may be, for example, SUS, aluminum, copper, nickel, iron, titanium, carbon, or the like.

[0027] The shape of the positive electrode current collector layer is not particularly limited, and examples thereof include foil, plate, mesh, etc. Among these, the foil shape is preferred.

[0028] The positive electrode current collector layer may extend from an end face of the electrode stack, and the extending portion may collect the plurality of positive electrode current collector layers. In particular, all of the plurality of positive electrode current collector layers may be collected to form a foil collecting portion.

[0029] (Cathode active material layer) The positive electrode active material layer contains at least a positive electrode active material, and preferably further contains a solid electrolyte described below. In addition, depending on the intended use and purpose, it may contain additives used in positive electrode active material layers of solid-state batteries, such as a conductive additive or a binder.

[0030] The material of the positive electrode active material is not particularly limited. For example, the positive electrode active material may be lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), Li 1.5 Co 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3O2, Li 1+x Mn 2-x-y M y It may be a different element-substituted Li-Mn spinel having a composition represented by O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn), or the like.

[0031] The conductive additive is not particularly limited, and may be, for example, a carbon material such as VGCF (Vapor Grown Carbon Fiber) or carbon nanofiber, or a metal material.

[0032] The binder is not particularly limited, and may be, for example, polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), butadiene rubber (BR), styrene butadiene rubber (SBR), or a combination thereof.

[0033] (solid electrolyte layer) The solid electrolyte layer includes at least a solid electrolyte. The solid electrolyte is not particularly limited, and any material that can be used as a solid electrolyte for a solid-state battery can be used. For example, the solid electrolyte may be a sulfide solid electrolyte, an oxide solid electrolyte, a polymer electrolyte, or the like.

[0034] Examples of sulfide solid electrolytes include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, and argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include Li2S-P2S5-based (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2(Li 13 GeP3S 16 , Li 10 GeP2S 12 ), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl xetc.; or combinations thereof, but are not limited to these.

[0035] An example of an oxide solid electrolyte is Li7La3Zr2O 12、 Li 7-x La3Zr 1-x Nb x O 12、 Li 7-3x La3Zr2Al x O 12 , Li 3x La 2 / 3-x TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+x Al x Ge 2-x (PO4)3, Li3PO4, Li 3+x PO 4-x N x (LiPON), etc., but are not limited to these.

[0036] Polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and the like, and copolymers thereof.

[0037] The solid electrolyte may be glass or crystallized glass (glass ceramic). The solid electrolyte layer may contain, in addition to the solid electrolyte described above, a conductive additive, a binder, and the like, as needed. For the conductive additive and the binder, see the above description of the positive electrode active material layer.

[0038] (Negative electrode active material layer) The negative electrode active material layer contains at least a negative electrode active material, and preferably further contains the above-mentioned solid electrolyte. In addition, depending on the intended use and purpose, it may contain additives used in negative electrode active material layers of solid-state batteries, such as a conductive additive and a binder.

[0039] The material of the negative electrode active material is not particularly limited, but is preferably capable of absorbing and releasing metal ions such as lithium ions. For example, the negative electrode active material may be, but is not limited to, an oxide-based negative electrode active material, an alloy-based negative electrode active material, a carbon material, or the like.

[0040] The oxide-based negative electrode active material is not particularly limited, and examples thereof include lithium titanate (LTO) particles.

[0041] The alloy-based negative electrode active material is not particularly limited, and examples thereof include Si alloy-based negative electrode active materials and Sn alloy-based negative electrode active materials. Examples of Si alloy-based negative electrode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, and solid solutions thereof. The Si alloy-based negative electrode active material can also contain elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti, etc. The Sn alloy-based negative electrode active material can also contain tin, tin oxide, tin nitride, or solid solutions thereof. The Sn alloy-based negative electrode active material can also contain elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si, etc.

[0042] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, graphite, and the like.

[0043] For the solid electrolyte used in the negative electrode active material layer, the above description regarding the solid electrolyte layer can be referred to, and for the conductive additive and binder, the above description regarding the positive electrode active material layer can be referred to.

[0044] (negative electrode current collector layer) The conductive material used for the negative electrode current collector layer is not particularly limited, and may be, for example, SUS, aluminum, copper, nickel, iron, titanium, carbon, or the like, but is not limited to these.

[0045] The shape of the negative electrode current collector layer is not particularly limited, and examples thereof include foil, plate, mesh, etc. Among these, foil is preferred.

[0046] The negative electrode current collector layer may extend from an end face of the electrode stack, and the extending portion may collect the plurality of negative electrode current collector layers. In particular, all of the plurality of negative electrode current collector layers may be collected to form a foil collecting portion.

[0047] <Collector terminal> 1 , the stacked battery 10 of the present disclosure has a current collecting terminal 120. The current collecting terminal 120 houses the electrode stack 110 together with an outer casing 130. The current collecting terminals may be disposed so as to face a pair of end faces of the electrode stack.

[0048] The shape of the current collecting terminal is not particularly limited except that it has a slit portion, which will be described later, but the current collecting terminal may have a peripheral surface adjacent to the surface facing the electrode stack.

[0049] The size, material, etc. of the current collector terminals are not particularly limited and can be appropriately set according to the application of the laminated battery, etc. For example, the material of the current collector terminals may be a metal material, particularly stainless steel or aluminum.

[0050] (Slit part) 1, the current collecting terminal 120 has one slit portion 120a in a part of the surface facing the electrode stack 110. A foil collecting portion 111a is inserted into and joined to this slit portion 120a. This electrically connects the electrode stack 110 to the current collecting terminal 120 via the multiple current collecting foils 111.

[0051] The depth of the slit portion 120a may be 30% or more of the thickness of the current collecting terminal 120. The depth of the slit portion 120a may be 40% or more, 50% or more, or 60% or more of the thickness of the current collecting terminal 120, and may be 100% or less, 90% or less, 80% or less, 70% or less, 60% or less, or 50% or less. When the depth of the slit portion 120a is 100% of the thickness of the current collecting terminal 120, this means that the slit portion 120a penetrates the current collecting terminal 120. Note that, in the present disclosure, the thickness of the current collecting terminal 120 refers to the length in the depth direction of the slit portion 120a, i.e., the direction in which the slit portion 120a extends.

[0052] The slit portion may be formed in the center of the surface facing the electrode stack. By adopting such a configuration, the space required for collecting the current collecting foil can be reduced, thereby improving the structural efficiency of the battery.

[0053] The slits may be formed parallel to the surface direction of the electrode laminate.

[0054] The shape, size, thickness, etc. of the slit portion are not particularly limited, and can be set appropriately taking into consideration the ease of inserting and joining the foil collecting portion into the slit portion, etc.

[0055] <Exterior body> The laminated battery 10 of the present disclosure has an exterior body 130. The exterior body 130 houses the electrode stack 110 together with the current collecting terminals 120. The exterior body may be joined to the peripheral surface of the current collecting terminals, thereby housing the electrode stack together with the current collecting terminals.

[0056] An example of the exterior body is a laminate film. The laminate film may have a sealant resin layer, a metal layer, and a protective resin layer in this order along the thickness direction. Examples of materials for the sealant resin layer include olefin-based resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective resin layer include polyethylene terephthalate (PET) and nylon.

[0057] The thickness of each layer constituting the laminate film and the laminate film itself are not particularly limited. The thickness of the sealant resin layer is, for example, 40 μm or more and 100 μm or less. The thickness of the metal layer is, for example, 30 μm or more and 60 μm or less. The thickness of the protective resin layer is, for example, 20 μm or more and 60 μm or less. The thickness of the laminate film is, for example, 80 μm or more and 250 μm or less.

[0058] <<Laminated Battery Manufacturing Method>> As illustrated in FIG. 2 , the method of the present disclosure for manufacturing a stacked battery 10 includes the following steps: providing an electrode stack 110 and a current collecting terminal 120; inserting a foil collecting portion 111a into a slit portion 120a of the current collecting terminal; arranging resistance welding electrodes 20 on both sides of the current collecting terminal so as to sandwich the slit portion; pressing the current collecting terminal with the resistance welding electrodes while passing current through the resistance welding electrodes to resistance-weld the current collecting foil within the slit portion; and housing the electrode stack in the current collecting terminal and an outer casing 130.

[0059] By manufacturing the stacked battery 10 using this method, it is possible to obtain a stacked battery that achieves both improved structural efficiency and prevention of breakage of the current collecting foil 111.

[0060] Each step in the method of the present disclosure will now be described.

[0061] <Electrode laminate and current collecting terminal providing step> As illustrated in FIG. 2( a ), the method of the present disclosure includes providing an electrode stack 110 and a current collecting terminal 120 .

[0062] The method for providing the electrode laminate is not particularly limited. For example, the electrode laminate can be provided by stacking the layers constituting the electrode laminate in a desired order. The method for stacking the layers is not particularly limited, and examples include a method in which the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer are formed by powder compaction, and then the layers are stacked in a desired order. Another example includes a method in which a composite slurry capable of forming the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer is applied to a substrate, and then dried, and the layers are stacked in a desired order. The substrate of the negative electrode active material layer may be, for example, a negative electrode current collector layer. The substrate of the solid electrolyte layer may be, for example, a peelable metal foil such as aluminum foil. The substrate of the positive electrode active material layer may be, for example, a positive electrode current collector layer.

[0063] The method for providing the current collecting terminal is not particularly limited, and examples thereof include a method in which a slit portion is formed by cutting or the like on one surface of a metal material that can be used as the current collecting terminal.

[0064] <Foil collecting part insertion process> 2(b), the method of the present disclosure includes inserting a foil collecting portion 111a into a slit portion 120a of a current collecting terminal. The method of inserting the foil collecting portion into the slit portion is not particularly limited.

[0065] <Resistance welding electrode placement process> 2(c), the method of the present disclosure includes arranging the resistance welding electrodes 20 on both sides of the current collecting terminal 120 so as to sandwich the slit portion 120a. That is, the resistance welding electrodes 20 are arranged on both sides of the current collecting terminal 120 so that the surfaces of the tips of the resistance welding electrodes 20 are parallel to the direction in which the slit portion 120a extends.

[0066] <Resistance welding process> As illustrated in FIG. 2( c), the method disclosed herein includes pressing the current collecting terminal 120 with the resistance welding electrode 20 while passing current through the resistance welding electrode 20 to resistance-weld the current collecting foil 111 within the slit 120 a. In FIG. 2( c), the upward and downward white arrows indicate the state in which the resistance welding electrode is pressing the current collecting terminal, and the single downward arrow indicates the state in which current is passing through the resistance welding electrode. Joining the current collecting terminal and the current collecting foil by resistance welding effectively prevents the current collecting foil from breaking. The pressure during pressing and the magnitude of the current during current passing can be appropriately set taking into account the depth of the slit 120 a, the materials of the current collecting terminal 120 and the current collecting foil 111, and the like.

[0067] <Electrode Stack Housing Process> As illustrated in FIG. 2(d), the method of the present disclosure includes housing the electrode stack 110 between a current collecting terminal 120 and an exterior body 130. An example of the exterior body 130 is a laminate film. In this case, the laminate film may be formed by winding the electrode stack 110 and the current collecting terminal 120, and housing the electrode stack 110 together with the current collecting terminal 120. The laminate film may also be formed by two films, and in this case, the electrode stack 110 and the current collecting terminal 120 may be sandwiched between the two films from above and below in the stacking direction of the electrode stack 110, and housing the electrode stack 110 together with the current collecting terminal 120. [Explanation of symbols]

[0068] 10. Stacked battery 100 stacked battery unit 110 Electrode laminate 111 Current collecting foil 111a Foil collecting section 120 Current collector terminal 120a slit section 130 Exterior body 20 Resistance welding electrodes

Claims

1. an electrode stack; current collecting terminals, and an exterior housing that houses the electrode stack together with the current collecting terminal; A stacked battery having: A plurality of current collecting foils extend from the end faces of the electrode stack, the current collecting terminal has one slit portion in a part of the surface facing the electrode stack, and all of the plurality of current collecting foils are collected to form a foil collecting portion, and the foil collecting portion is inserted into and joined to the slit portion, whereby the electrode stack is electrically connected to the current collecting terminal via the plurality of current collecting foils. Stacked battery.

2. 2. The stacked battery according to claim 1, wherein the depth of the slit portion is 30% or more of the thickness of the current collector terminal.

3. A method for producing the stacked battery according to claim 1 or 2, comprising the following steps: providing the electrode stack and the current collecting terminal; inserting the foil collecting portion into the slit portion of the current collecting terminal; Resistance welding electrodes are disposed on both sides of the current collecting terminal so as to sandwich the slit portion. pressing the current collecting terminal with the resistance welding electrode while passing current through the resistance welding electrode to resistance-weld the current collecting foil within the slit portion; and The electrode stack is housed in the collector terminal and the exterior body.

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