Solid-state battery, manufacturing method of the same, and battery module

Abstract

To provide a solid-state battery having high volume efficiency in a lamination direction of an electrode lamination body and high reliability of an insulation by an insulating member, a manufacturing method of the same, and a battery module including the solid-state battery.SOLUTION: A solid-state battery 10 has an electrode lamination body 110. The electrode lamination body 110 includes a first current collector layer 111, a first electrode active material layer 112, a solid electrolyte layer 113, a second electrode active material layer 114, and a second current collector layer 115 in this order. The electrode lamination body has a body region 110a, and a tapered region 110b formed at an end. An insulating member 120 is disposed from at least a part of one inclined surface of the tapered region to at least a part of the other inclined surface via an end surface of the electrode lamination body. A length L of the insulating member in a lamination direction of the electrode lamination body is smaller than a thickness T of the main body region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a solid-state battery, a manufacturing method thereof, and a battery module. [Background technology]

[0002] In the automotive industry, growing environmental awareness has led to the development of electric vehicles, hybrid vehicles, etc., and this has led to a growing demand for high-voltage secondary batteries. Meanwhile, in the field of portable electronic devices, the widespread adoption and development of these devices has led to a demand for small, lightweight, high-capacity secondary batteries capable of long periods of continuous operation.

[0003] Known high-voltage, high-capacity batteries include, for example, batteries that include an electrode stack having, in this order, 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.

[0004] In such batteries, for example, if the current collector layer of one electrode extends beyond the electrode stack, it may come into contact with the current collector layer and / or active material layer of the other electrode, resulting in a short circuit. The portion of the current collector layer extending beyond the electrode stack is also called a current collector tab. This short circuit is particularly likely to occur when the area of the current collector layer of one electrode is larger than the area of the current collector layer of the other electrode. Therefore, technologies to prevent such short circuits have been developed.

[0005] For example, Patent Document 1 discloses a method for manufacturing a stacked all-solid-state battery, which includes preparing a first stacked body in which a solid electrolyte layer, a first active material layer (electrode active material layer), a first current collector layer having a first current collector tab extending to the side of the stacked all-solid-state battery, a first active material layer, and a solid electrolyte layer are stacked in this order; applying an insulating coating liquid to an end of the first stacked body to form an insulating part (insulating member); and assembling the first stacked body with the insulating part formed thereon, a second active material layer, and a second current collector tab extending to the side of the stacked all-solid-state battery. and a second current collector layer having a second current collecting tab, to prepare a battery structure (electrode laminate) having a plurality of second laminates, each of which is formed by laminating a second current collector layer having a second current collecting tab, a second active material layer, a solid electrolyte layer, a first active material layer, a first current collector layer having a first current collecting tab, a first active material layer, a solid electrolyte layer, and a second active material layer in this order; and joining a plurality of second current collecting tabs extending from the plurality of second current collectors in the battery structure. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-049696 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, when an electrode laminate is manufactured by applying an insulating member to an end surface of a pre-laminate composed of layers other than the second current collector layer of the electrode laminate and then laminating the second current collector layer on the pre-laminate, applying the insulating member to the end surface of the pre-laminate may result in the insulating member being applied to a part of the main surface adjacent to the end surface of the pre-laminate. The present inventors have found that in such a case, the thickness of the portion of the battery where the insulating member is formed on the main surface of the pre-laminate may be thicker than the thickness of the other portions, and as a result, the volumetric efficiency of the battery in the stacking direction of the electrode laminate may decrease.

[0008] The present inventors have also discovered that in such cases, the second current collector layer and the insulating member may interfere with each other, resulting in reduced reliability of insulation provided by the insulating member, such as the insulating member peeling off from the electrode stack.

[0009] The present disclosure aims to provide a solid-state battery having high volumetric efficiency in the stacking direction of an electrode stack and high reliability of insulation by an insulating member, a method for manufacturing the same, and a battery module having such a solid-state battery. [Means for solving the problem]

[0010] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> A solid-state battery having an electrode stack, the electrode laminate has, in this order, a first current collector layer, a first electrode active material layer, a solid electrolyte layer, a second electrode active material layer, and a second current collector layer; the electrode stack has a main body region and a tapered region formed at an end thereof; an insulating member is disposed from at least a portion of one of the slopes of the tapered region, via an end face of the electrode stack, to at least a portion of the other slope; and The length of the insulating member in the stacking direction of the electrode stack is smaller than the thickness of the main body region. solid state battery. <Aspect 2> 2. The solid-state battery of claim 1, wherein the tapered region of the electrode stack is a region formed by cutting at least a portion of a region formed due to the second electrode active material layer being smaller in a planar direction than the first electrode active material layer in the stacking direction of the electrode stack. <Aspect 3> A battery module comprising the solid-state battery according to embodiment 1 or 2. <Aspect 4> A method for producing a solid-state battery according to embodiment 1, comprising the steps of: (a) laminating the first current collector layer, the first electrode active material layer, the solid electrolyte layer, and the second electrode active material layer in this order to form a preliminary laminate having the tapered region at an end thereof; (b) applying the insulating member from at least a part of one slope of the tapered region, via the end face of the preliminary laminate, to at least a part of the other slope, such that the length of the insulating member in the stacking direction of the electrode laminate is smaller than the thickness of the main body region; (c) laminating the second current collector layer onto the pre-laminate after applying the insulating member to form the electrode laminate. <Aspect 5> The method of aspect 4, further comprising: cutting, in the step (a), at least a portion of a region formed due to the second electrode active material layer being smaller in the planar direction than the first electrode active material layer, in the stacking direction of the electrode stack, to form the tapered region. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a solid-state battery having high volumetric efficiency in the stacking direction of the electrode stack and high reliability of insulation by the insulating member, a method for manufacturing the same, and a battery module having such a solid-state battery. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic plan view showing an example of a solid state battery according to the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of an arrangement of insulating members in the solid state battery of the present disclosure. [Figure 3] FIG. 3 is a schematic diagram illustrating an example of a method of the present disclosure for producing a solid-state battery. [Figure 4] FIG. 4 is a schematic perspective view showing an example of a battery module according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] 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.

[0014] 《Solid-state battery》 As illustrated in FIG. 1 , a solid-state battery 10 according to the present disclosure includes an electrode stack 110. As illustrated in FIG. 2 , the electrode stack 110 includes a first current collector layer 111, a first electrode active material layer 112, a solid electrolyte layer 113, a second electrode active material layer 114, and a second current collector layer 115, in this order. The electrode stack includes a main body region 110a and a tapered region 110b formed at an end. An insulating member 120 is disposed from at least a portion of one slope of the tapered region, through the end face of the electrode stack, to at least a portion of the other slope. The length L of the insulating member in the stacking direction of the electrode stack is smaller than the thickness T of the main body region. FIG. 2 is a schematic cross-sectional view of an enlarged view of the insulating member 120 of the solid-state battery 10 according to the present disclosure.

[0015] The present inventors have discovered that by making the length of the insulating member in the stacking direction of the electrode stack shorter than the thickness of the main body region, the volumetric efficiency of the battery in the stacking direction of the electrode stack can be increased, and that, particularly when multiple electrode stacks are stacked, the insulating members can be prevented from interfering with each other. Furthermore, they have discovered that by arranging the insulating member from at least a portion of one slope of the tapered region of the electrode stack, via the end face of the electrode stack, to at least a portion of the other slope, the insulating member is less likely to fall off, and as a result, the reliability of insulation provided by the insulating member is increased.

[0016] In the context of the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as the electrolyte, and therefore a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as the electrolyte. Alternatively, 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.

[0017] In the present disclosure, a "pre-laminate" refers to a laminate having a first current collector layer, a first electrode active material layer, a solid electrolyte layer, and a second electrode active material layer in this order. An "electrode laminate" refers to a laminate in which a second current collector layer is laminated on a pre-laminate.

[0018] As illustrated in FIG. 2 , in the solid-state battery 10 of the present disclosure, an insulating member 120 is disposed from at least a portion of one slope of the tapered region 110b, across the end face of the electrode laminate 110, and over at least a portion of the other slope. The insulating member 120 may be disposed so as to cover the first current collector layer 111, and in particular, may be disposed so as to cover the first current collector layer 111 and the first electrode active material layer 112. This configuration makes it easier to prevent a short circuit between the second current collector layer 115 and the first current collector layer 111 and / or the first electrode active material layer 112. The insulating member 120 may be disposed from a portion of one slope formed by the second electrode active material layer 114, across the end face of the electrode laminate 110, and over to a portion of the other slope formed by the second electrode active material layer 114. In particular, as illustrated in FIG. 2, the insulating member 120 may be disposed so as to overlap the second electrode active material layer 114 .

[0019] The tapered region of the electrode stack may be formed by cutting at least a portion of a region formed due to the second electrode active material layer being smaller in the planar direction than the first electrode active material layer in the planar direction of the electrode stack. This configuration can increase the volumetric efficiency of the battery in the planar direction of the electrode stack.

[0020] For example, in a lithium-ion secondary battery, the positive electrode active material layer may be made smaller than the negative electrode active material layer to prevent dendrite deposition in the negative electrode active material layer. Therefore, when the positive electrode active material layer is made smaller than the negative electrode active material layer, the first current collector layer may be a negative electrode current collector layer, the first electrode active material layer may be a negative electrode active material layer, the second electrode active material layer may be a positive electrode active material layer, and the second current collector layer may be a positive electrode current collector layer.

[0021] The elements that make up the battery of the present disclosure will be described below.

[0022] <Electrode laminate> The solid state battery 10 of the present disclosure has an electrode stack 110. The electrode stack functions as the power generating element of the battery.

[0023] The electrode laminate has a first current collector layer, a first electrode active material layer, a solid electrolyte layer, a second electrode active material layer, and a second current collector layer, in this order. Preferably, the electrode laminate has a first electrode active material layer, a solid electrolyte layer, a second electrode active material layer, and a second current collector layer, in this order, on both sides of the first current collector layer. That is, the electrode laminate may have a second current collector layer, a second electrode active material layer, a solid electrolyte layer, a first electrode active material layer, a first current collector layer, a first electrode active material layer, a solid electrolyte layer, a second electrode active material layer, and a second current collector layer, in this order.

[0024] The electrode stack has a body region and tapered regions formed at the edges, where body region refers to the major portion of the electrode stack that has a substantially uniform thickness and is not tapered.

[0025] The shape of the electrode laminate in the surface direction is not particularly limited, and may include, for example, a top surface, a bottom surface opposite the top surface, and four side surfaces connecting the top surface and the bottom surface. The shape of the top surface is not particularly limited, and examples thereof include quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms. The shape of the top surface may also be polygonal other than a quadrilateral, or may be a curved shape such as a circle. The shape of the bottom surface may be the same as the shape of the top surface. The shape of the side surface is not particularly limited, and examples thereof include quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms.

[0026] The size of the electrode laminate is not particularly limited, and can be appropriately designed depending on, for example, the desired battery characteristics.

[0027] In the electrode laminate, the first current collector layer may be a negative electrode current collector layer, the first electrode active material layer may be a negative electrode active material layer, the second electrode active material layer may be a positive electrode active material layer, and the second current collector layer may be a positive electrode current collector layer. That is, the electrode laminate may have 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 material of each layer is not particularly limited, and materials commonly used as materials for constituting each layer can be used. The thickness of each layer is not particularly limited.

[0028] <Insulating materials> The shape of the insulating member 120 is not particularly limited.

[0029] The size of the insulating member 120 is not particularly limited, but can be appropriately designed taking into consideration the volumetric efficiency of the battery and the like.

[0030] The insulating member 120 may contain a thermoplastic resin or may be a thermoplastic resin. There are no particular limitations on the thermoplastic resin, and it may be a non-reactive or reactive type. There are no particular limitations on the non-reactive thermoplastic resin, and examples thereof include ethylene vinyl acetate (EVA)-based, synthetic rubber-based, olefin-based, polyamide-based, and polyester-based resins such as polyethylene terephthalate (PET). There are no particular limitations on the reactive resin, and examples thereof include urethane-based resins.

[0031] The insulating member 120 may contain a curable resin or may be a curable resin. The curable resin is not particularly limited, and examples thereof include a thermosetting resin and a photocurable resin. Examples of such resins include acrylic and epoxy resins.

[0032] By using such a resin as the insulating member 120, it is easy to arrange the insulating member 120 on the end face of the electrode stack 110.

[0033] The insulating member 120 may be an insulating tape, which may be a double-sided tape.

[0034] By using an insulating tape as the insulating member 120, the space occupied by the insulating member 120 is reduced, and therefore the volumetric efficiency of the battery in the surface direction of the electrode stack can be further improved.

[0035] <Laminating film> The solid state battery 10 of the present disclosure may have a laminate film 130. The laminate film may house an electrode stack. Specifically, the laminate film may house the electrode stack by rolling it up. The laminate film may also be composed of first and second films, and in this case, the electrode stack may be housed by being sandwiched between the first and second films from above and below in the stacking direction of the electrode stack.

[0036] 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 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.

[0037] 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.

[0038] <Collector terminal> The solid state battery 10 of the present disclosure may further include a current collecting terminal 140. The current collecting terminal may be electrically connected to the current collecting portion of the electrode laminate. The material of the current collecting terminal is not particularly limited as long as it has a current collecting function, and examples include copper and aluminum. As illustrated in FIG. 1, the current collecting terminals may be disposed on a pair of opposing side surfaces of the electrode laminate.

[0039] The shape and size of the current collecting terminal are not particularly limited.

[0040] When the battery of the present disclosure has a current collecting terminal, the laminate film may house the electrode laminate together with the current collecting terminal. Specifically, the laminate film may house the electrode laminate together with the current collecting terminal by winding the electrode laminate and the current collecting terminal. The laminate film may also be composed of first and second films. In this case, the first and second films may sandwich the electrode laminate and the current collecting terminal from above and below in the stacking direction of the electrode laminate, housing the electrode laminate together with the current collecting terminal.

[0041] The battery may be a lithium-ion secondary battery. Examples of uses for the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered automobiles, and diesel-powered automobiles. In particular, the battery is preferably 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.

[0042] <<Solid-state battery manufacturing method>> As illustrated in FIG. 3 , the method of the present disclosure for manufacturing the solid-state battery 10 includes the following steps: (a) stacking a first current collector layer 111, a first electrode active material layer 112, a solid electrolyte layer 113, and a second electrode active material layer 114 in this order to form a pre-laminate 100 having a tapered region 110 b at an end thereof; (b) applying an insulating member from at least a part of one slope of the tapered region, through the end face of the pre-laminate, to at least a part of the other slope thereof, such that the length L of the insulating member 120 in the stacking direction of the electrode laminate is smaller than the thickness T of the main body region 110 b; and (c) after applying the insulating member, stacking a second current collector layer on the pre-laminate to form an electrode laminate.

[0043] According to the method of the present disclosure, a solid-state battery can be manufactured that has high volumetric efficiency in the stacking direction of the electrode stack and high reliability of insulation by the insulating member.

[0044] As illustrated in FIG. 3( a), the method of the present disclosure includes (a) stacking a first current collector layer, a first electrode active material layer, a solid electrolyte layer, and a second electrode active material layer in this order to form a pre-laminate having tapered regions at its ends.

[0045] The method for laminating each layer is not particularly limited, and examples thereof include a method for laminating the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer by powder compaction, and a method for applying a composite slurry capable of forming each of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer to a substrate, drying the composite slurry, and laminating the layers.

[0046] The method for forming the preliminary laminate having a tapered region is not particularly limited, but examples thereof include a method of laminating the first current collector layer, the first electrode active material layer, the solid electrolyte layer, and the second electrode active material layer so that the layers decrease in size in the plane direction in this order.

[0047] 3(b), the method of the present disclosure may further include cutting, in the stacking direction of the electrode stack, at least a portion of the region formed due to the second electrode active material layer being smaller in the planar direction than the first electrode active material layer in step (a) to form a tapered region. Forming the tapered region in this manner can increase the volumetric efficiency of the battery in the planar direction of the electrode stack.

[0048] As illustrated in FIG. 3(c), the method of the present disclosure includes (b) applying an insulating member from at least a portion of one slope of the tapered region, through the end face of the pre-laminate, to at least a portion of the other slope, such that the length of the insulating member in the stacking direction of the electrode stack is smaller than the thickness of the main body region.

[0049] The method for applying the insulating member is not particularly limited. For example, when the insulating member is a thermoplastic resin, a method of applying or immersing a molten thermoplastic resin to a desired portion and then solidifying the resin can be used. For example, when the insulating member is a curable resin, a method of applying or immersing a curable resin to a desired portion and then hardening the resin can be used. For example, when the insulating member is an insulating tape, a method of attaching the insulating tape to a desired portion can be used.

[0050] As illustrated in FIG. 3(d), the method of the present disclosure includes (c) laminating a second current collector layer to the pre-laminate after applying the insulating member to form an electrode stack.

[0051] The method for laminating the second current collector layer on the preliminary laminate to form the electrode laminate is not particularly limited. For example, when the second current collector layer is a metal foil, a method may be used in which the metal foil is placed on the second electrode active material layer of the preliminary laminate and pressed.

[0052] Battery module 4, the battery module 1 of the present disclosure includes the solid-state battery 10 of the present disclosure. For the solid-state battery of the present disclosure, reference can be made to the above description regarding the solid-state battery of the present disclosure.

[0053] As described above, in the solid-state battery of the present disclosure, the length of the insulating member in the stacking direction of the electrode stack is smaller than the thickness of the main body region of the electrode stack. Therefore, for example, in a battery module of the present disclosure having a plurality of solid-state batteries of the present disclosure, the effect of improving the volumetric efficiency of the battery in the stacking direction of the electrode stack becomes even more pronounced.

[0054] The number of solid-state batteries of the present disclosure in the battery module of the present disclosure is not particularly limited and may be at least one. In the battery module of the present disclosure, all batteries may be solid-state batteries of the present disclosure. Note that, although FIG. 4 illustrates an embodiment in which the number of solid-state batteries is two, the number of solid-state batteries in the battery module of the present disclosure is not limited to this. [Explanation of symbols]

[0055] 1 Battery Module 10 solid state battery 100 Pre-laminate 110 Electrode laminate 110a Main body area 110b Tapered region 111 First current collector layer 112 First electrode active material layer 113 Solid electrolyte layer 114 Second electrode active material layer 115 Second current collector layer 120 Insulating material 130 Laminating Film 140 Current collector terminal

Claims

1. A solid-state battery having an electrode stack, the electrode stack has a first current collector layer, a first electrode active material layer, a solid electrolyte layer, a second electrode active material layer, and a second current collector layer in this order; the electrode stack has a main body region and a tapered region formed at an end thereof; an insulating member is disposed from at least a portion of one of the slopes of the tapered region, via an end face of the electrode stack, to at least a portion of the other slope; and The length of the insulating member in the stacking direction of the electrode stack is smaller than the thickness of the main body region. solid state battery.

2. 2. The solid-state battery according to claim 1, wherein the tapered region of the electrode stack is a region formed by cutting at least a part of a region formed due to the second electrode active material layer being smaller in a planar direction than the first electrode active material layer in the stacking direction of the electrode stack.

3. A battery module comprising the solid-state battery according to claim 1 or 2.

4. A method for producing the solid state battery according to claim 1, comprising the steps of: (a) laminating the first current collector layer, the first electrode active material layer, the solid electrolyte layer, and the second electrode active material layer in this order to form a preliminary laminate having the tapered region at an end thereof; (b) applying the insulating member from at least a part of one slope of the tapered region, via the end face of the preliminary laminate, to at least a part of the other slope, such that the length of the insulating member in the stacking direction of the electrode laminate is smaller than the thickness of the main body region; (c) laminating the second current collector layer to the pre-laminate after applying the insulating member to form the electrode stack.

5. 5. The method according to claim 4, further comprising: cutting, in the step (a), at least a part of a region formed due to the second electrode active material layer being smaller in the planar direction than the first electrode active material layer, in the stacking direction of the electrode stack, to form the tapered region.

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