Solid-state battery, method for manufacturing same, and battery module

Abstract

The invention relates to a solid-state battery, a method of manufacturing the same, and a battery module. A solid-state battery of the present disclosure has an electrode laminate. 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. The electrode laminate has a main body region and a tapered region formed at an end portion. An insulating member is disposed from at least a part of one inclined surface in the tapered region to at least a part of the other inclined surface via an end surface of the electrode laminate. The length of the insulating member in the lamination direction of the electrode laminate is smaller than the thickness of the body region.

Description

Technical Field

[0001] The present disclosure relates to a solid battery, a method for manufacturing the same, and a battery module. Background Art

[0002] In the automotive industry, growing awareness of environmental issues has led to the development of battery-electric vehicles and hybrid electric vehicles, resulting in an increasing demand for high-voltage secondary batteries. Meanwhile, in the field of portable electronic devices, the widespread adoption and growth of these devices has also led to a demand for high-capacity secondary batteries that are compact, lightweight, and capable of long-term continuous operation.

[0003] As a high-voltage and high-capacity battery, for example, a battery including an electrode stack having a negative electrode collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode collector layer in this order is known.

[0004] In such a battery, for example, when the current collector layer of one electrode extends from the electrode stack, it may sometimes come into contact with the current collector layer and / or active material layer of the other electrode and cause a short circuit. In addition, the portion of the current collector layer extending from the electrode stack is also called a collector lug. When the area of the current collector layer of one electrode is formed to be larger than the area of the current collector layer of the other electrode, this short circuit is particularly likely to occur. Therefore, technology to prevent such short circuits is being developed.

[0005] For example, Japanese Patent Application Laid-Open No. 2018-049696 discloses a method for manufacturing a stacked all-solid-state battery. This method involves preparing a first stack comprising a solid electrolyte layer, a first active material layer (electrode active material layer), a first current collector layer, a first active material layer, and a solid electrolyte layer stacked in this order. The first current collector layer has a first collector tab extending laterally of the stacked all-solid-state battery. An insulating coating liquid is applied to the ends of the first stack to form an insulating portion (insulating member). The first stack with the insulating portion, a second active material layer, and a second current collector layer are stacked. This results in a battery structure (electrode stack) comprising a plurality of second stacks. The second stack comprises, in this order, a second current collector layer having a second collector tab, a second active material layer, a solid electrolyte layer, a first active material layer, a first current collector layer having a first collector tab, a first active material layer, a solid electrolyte layer, and a second active material layer. The second current collector layer has a second collector tab extending laterally of the stacked all-solid-state battery. A plurality of second current collector tabs extending from the plurality of second current collectors in the battery structure are joined. Summary of the Invention

[0006] For example, an insulating member is applied to the end face of a preliminary stack composed of layers other than the second current collector layer in the electrode stack. Moreover, in the case of manufacturing the electrode stack by laminating the second current collector layer on the preliminary stack, it is desirable to apply an insulating member to the end face of the preliminary stack. In this way, the insulating member is sometimes applied to a portion of the main surface adjacent to the end face of the preliminary stack. The inventors of the present application have found that, in this case, the thickness of the portion of the battery where the insulating member is formed on the main surface of the preliminary stack is sometimes thicker than the thickness of other portions. The inventors of the present application have found that, as a result, the volume efficiency of the battery in the stacking direction of the electrode stack is sometimes reduced.

[0007] The inventors of the present application have found that in this case, the second current collector layer and the insulating member may interfere with each other, resulting in a decrease in insulation reliability of the insulating member, such as separation of the insulating member from the electrode stack.

[0008] An object of the present disclosure is to provide a solid battery having high volume 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 including such a solid battery.

[0009] The inventors of the present application have discovered that the above-mentioned problems can be solved by the following means.

[0010] Method 1

[0011] A solid battery having an electrode stack, wherein:

[0012] The electrode stack comprises 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.

[0013] The electrode stack has a main body region and a tapered region formed at an end portion.

[0014] An insulating member is arranged from at least a portion of one inclined surface in the tapered region via an end surface of the electrode stack to at least a portion of the other inclined surface, and

[0015] The length of the insulating member in the stacking direction of the electrode stack is smaller than the thickness of the main body region.

[0016] Method 2

[0017] In the solid state battery according to embodiment 1,

[0018] The tapered region of the electrode stack is formed by cutting at least a portion of a region formed by the second electrode active material layer being smaller than the first electrode active material layer in the plane direction in the electrode stack in the stacking direction.

[0019] Method 3

[0020] A battery module, wherein:

[0021] The battery module includes the solid state battery according to embodiment 1 or 2.

[0022] Method 4

[0023] A method for manufacturing a solid battery is the method for manufacturing a solid battery according to embodiment 1, wherein:

[0024] The manufacturing method of the solid battery includes the following steps:

[0025] (a) stacking 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 stack having the tapered region at an end portion;

[0026] (b) applying the insulating member 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 from at least a portion of one inclined surface in the tapered region via the end surface of the preliminary stack to at least a portion of the other inclined surface; and

[0027] (c) After applying the insulating member, the second current collector layer is stacked on the preliminary stack to form the electrode stack.

[0028] Method 5

[0029] In the method for manufacturing a solid battery according to embodiment 4,

[0030] The step (a) further includes cutting at least a portion of a region formed by the second electrode active material layer being smaller than the first electrode active material layer in a planar direction of the electrode stack to form the tapered region.

[0031] According to the present disclosure, it is possible to provide a solid battery having high volume 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 including the solid battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0033] Figure 1 is a schematic plan view showing an example of a solid state battery disclosed herein;

[0034] Figure 2 is a schematic cross-sectional view showing an example of an arrangement of insulating members in the solid battery of the present disclosure;

[0035] Figure 3A is a schematic diagram showing an example of the method of the present disclosure for manufacturing a solid state battery;

[0036] Figure 3B is a schematic diagram showing an example of the method of the present disclosure for manufacturing a solid state battery;

[0037] Figure 3C is a schematic diagram showing an example of the method of the present disclosure for manufacturing a solid state battery;

[0038] Figure 3D is a schematic diagram showing an example of the method of the present disclosure for manufacturing a solid state battery;

[0039] Figure 4 This is a schematic perspective view showing an example of the battery module of the present disclosure. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the present disclosure is not limited to the following embodiments and can be implemented with various modifications within the scope of the present disclosure. Furthermore, the dimensional relationships in the accompanying drawings do not reflect actual dimensional relationships.

[0041] solid-state batteries

[0042] like Figure 1 As shown, the solid battery 10 of the present disclosure has an electrode stack 110. Figure 2 As shown, the electrode stack 110 has 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 has a main region 110a and a tapered region 110b formed at the end. An insulating member 120 is arranged from at least a portion of one inclined surface in the tapered region through the end face of the electrode stack to at least a portion of the other inclined surface. The length L of the insulating member in the stacking direction of the electrode stack is less than the thickness T of the main region. In addition, Figure 2 This is a schematic cross-sectional view showing an enlarged portion of the insulating member 120 of the solid battery 10 of the present disclosure.

[0043] The inventors of the present application have found that by making the length of the insulating member in the stacking direction of the electrode stack smaller than the thickness of the main body area, the volume efficiency of the battery in the stacking direction of the electrode stack is improved. The inventors of the present application have found that, especially in the case of stacking multiple electrode stacks, the insulating members can also be made not to interfere with each other. In addition, the inventors of the present application have found that by configuring the insulating member from at least a portion of one inclined surface in the tapered shape area of the electrode stack via the end face of the electrode stack to at least a portion of the other inclined surface, the insulating member is difficult to fall off. The inventors of the present application have found that, as a result, the reliability of the insulation based on the insulating member is improved.

[0044] In the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as its electrolyte. Thus, a solid-state battery may also use a combination of a solid electrolyte and a liquid electrolyte as its electrolyte. Furthermore, the solid-state battery of the present disclosure may also be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as its electrolyte.

[0045] In the present disclosure, a "preliminary 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 having a second current collector layer laminated on the preliminary laminate.

[0046] like Figure 2 As shown, in the solid battery 10 of the present disclosure, an insulating member 120 is configured from at least a portion of one slope in the conical shape region 110b via the end face of the electrode stack 110 to at least a portion of the other slope. The insulating member 120 can be configured in a manner that covers the first collector layer 111, and in particular, can be configured in a manner that covers the first collector layer 111 and the first electrode active material layer 112. By adopting such a structure, it is easy to prevent the second collector layer 115 from short-circuiting with the first collector layer 111 and / or the first electrode active material layer 112. The insulating member 120 can also be configured to extend from a first portion of one slope via the end face of the electrode stack 110 to a second portion of the other slope. The first portion is a portion formed by the second electrode active material layer 114. The second portion is a portion formed by the second electrode active material layer 114. In particular, as Figure 2 As shown, the insulating member 120 may also be configured to straddle the second electrode active material layer 114 .

[0047] The tapered region of the electrode stack may be formed by cutting at least a portion of the region formed by the second electrode active material layer being smaller than the first electrode active material layer in the planar direction of the electrode stack. By adopting this structure, the volumetric efficiency of the battery in the planar direction of the electrode stack can be improved.

[0048] For example, in lithium-ion secondary batteries, the positive electrode active material layer is sometimes made smaller than the negative electrode active material layer to prevent dendrites from precipitating into 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 can be the negative electrode current collector layer, and the first electrode active material layer can be the negative electrode active material layer. The second electrode active material layer can be the positive electrode active material layer, and the second current collector layer can be the positive electrode current collector layer.

[0049] Hereinafter, elements constituting the battery of the present disclosure will be described.

[0050] Electrode stack

[0051] The solid battery 10 of the present disclosure includes an electrode stack 110. The electrode stack functions as a power generation element of the battery.

[0052] The electrode stack comprises, in 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. Preferably, the electrode stack comprises, in order, a first electrode active material layer, a solid electrolyte layer, a second electrode active material layer, and a second current collector layer on both sides of the first current collector layer. That is, the electrode stack may comprise, in order, 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.

[0053] The electrode stack has a main body region and a tapered region formed at an end portion. Here, the main body region refers to a main portion having a substantially uniform thickness and not having a tapered shape.

[0054] The shape of the surface direction of the electrode stack is not particularly limited, and for example, it can have a top portion, a bottom portion facing the top portion, and four side portions connecting the top portion and the bottom portion. The shape of the top portion is not particularly limited, and for example, a quadrilateral such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram can be mentioned. In addition, the shape of the top portion can also be a polygon other than a quadrilateral, or a shape with a curve such as a circle. The shape of the bottom portion can be the same as that of the top portion. The shape of the side portion is not particularly limited, and for example, a quadrilateral such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram can be mentioned.

[0055] The size of the electrode stack is not particularly limited and can be appropriately designed according to, for example, desired battery characteristics and the like.

[0056] In the electrode stack, 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 stack may include, 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. The materials of each layer are not particularly limited, and commonly used materials can be used as the materials constituting each layer. The thickness of each layer is not particularly limited.

[0057] Insulation components

[0058] The shape of the insulating member 120 is not particularly limited.

[0059] The size of the insulating member 120 is not particularly limited and can be appropriately designed in consideration of the volumetric efficiency of the battery and the like.

[0060] Insulating member 120 may include a thermoplastic resin or may be a thermoplastic resin. Thermoplastic resins are not particularly limited and may be either non-reactive or reactive. Non-reactive thermoplastic resins are not particularly limited and include, for example, ethylene vinyl acetate (EVA), synthetic rubber, olefin, polyamide, or polyester resins such as polyethylene terephthalate (PET). Reactive resins are not particularly limited and include, for example, polyurethane resins.

[0061] 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 thermosetting resins and photocurable resins. Examples of these resins include acrylic or epoxy resins.

[0062] By using these resins as the insulating member 120 , it is easy to arrange the insulating member 120 on the end surface of the electrode stack 110 .

[0063] The insulating member 120 may be an insulating tape, and may be a double-sided tape.

[0064] By using an insulating tape as the insulating member 120 , the space occupied by the insulating member 120 is reduced, and thus the volume efficiency of the battery in the plane direction of the electrode stack can be further improved.

[0065] Laminated film

[0066] The solid-state battery 10 of the present disclosure may include a laminate film 130. The laminate film may house an electrode stack. Specifically, the laminate film may be wound around the electrode stack to house the electrode stack. Alternatively, the laminate film may be composed of a first film and a second film. In this case, the first and second films may sandwich the electrode stack from above and below in the stacking direction of the electrode stack to house the electrode stack.

[0067] The laminate film may include 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.

[0068] The layers comprising the laminate film and the thickness of the laminate film are not particularly limited. The thickness of the sealant resin layer is, for example, 40 μm to 100 μm. The thickness of the metal layer is, for example, 30 μm to 60 μm. The thickness of the protective resin layer is, for example, 20 μm to 60 μm. The thickness of the laminate film is, for example, 80 μm to 250 μm.

[0069] collector terminal

[0070] The solid 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 stack. The material of the current collecting terminal is not particularly limited as long as it has a current collecting function, and examples thereof include copper, aluminum, and the like. Figure 1 As shown, the current collecting terminals may be arranged on a pair of opposing side surfaces of the electrode stack.

[0071] The shape, size, etc. of the current collecting terminal are not particularly limited.

[0072] In the case of a battery of the present disclosure having a current collector terminal, the laminate film can accommodate the electrode stack and the current collector terminal together. Specifically, the laminate film can be wound around the electrode stack and the current collector terminal to accommodate the electrode stack and the current collector terminal together. Alternatively, the laminate film can be composed of a first film and a second film. In this case, the first film and the second film can be used to sandwich the electrode stack and the current collector terminal from above and below in the stacking direction of the electrode stack, thereby accommodating the electrode stack and the current collector terminal together.

[0073] The battery may be a lithium-ion secondary battery. Examples of battery applications include power sources for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline vehicles, diesel vehicles, and the like. It is particularly preferred to use the battery as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or battery electric vehicles (BEVs). Furthermore, the battery disclosed herein may be used as a power source for mobile vehicles other than vehicles (e.g., railways, ships, and aircraft), or as a power source for electrical products such as information processing devices.

[0074] Method for manufacturing solid-state batteries

[0075] like Figures 3A to 3D As shown, the method of the present disclosure for manufacturing the solid state battery 10 includes the following steps.

[0076] (a) The first current collector layer 111 , the first electrode active material layer 112 , the solid electrolyte layer 113 , and the second electrode active material layer 114 are sequentially stacked to form a preliminary stack 100 having a tapered region 110 b at an end portion.

[0077] (b) The insulating member 120 is applied such that its length L in the stacking direction of the electrode stack is smaller than the thickness T of the main body region 110 a from at least a portion of one inclined surface in the tapered region via the end surface of the preliminary stack to at least a portion of the other inclined surface.

[0078] (c) After applying the insulating member, the second current collector layer is stacked on the preliminary stack to form an electrode stack.

[0079] According to the method disclosed herein, a solid battery having high volume efficiency of the battery in the stacking direction of the electrode stack and high reliability of insulation by the insulating member can be manufactured.

[0080] like Figure 3A As shown, the method disclosed herein includes: (a) sequentially stacking a first current collector layer, a first electrode active material layer, a solid electrolyte layer, and a second electrode active material layer to form a preliminary stack having a tapered region at its end.

[0081] There are no particular limitations on the method for stacking the layers. For example, a method of stacking the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer by powder compaction can be used. Another method is to apply composite material slurries that can form the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer to a substrate, dry them, and then stack them.

[0082] The method for forming the preliminary laminate having the tapered region is not particularly limited, and one example is a method in which the first current collector layer, the first electrode active material layer, the solid electrolyte layer, and the second electrode active material layer are stacked in such a manner that the layers decrease in size in the plane direction.

[0083] like Figure 3B As shown, the method disclosed herein may further include, in step (a), cutting at least a portion of the region formed by 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 a tapered region. Forming the tapered region in this manner can improve the volumetric efficiency of the battery in the planar direction of the electrode stack.

[0084] like Figure 3C As shown, the method of the present disclosure includes: (b) applying an insulating member from at least a portion of one inclined surface in the tapered shape region via an end surface of the preliminary stack to at least a portion of the other inclined surface in such a manner 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.

[0085] There are no particular limitations on the method for applying the insulating member. For example, if the insulating member is a thermoplastic resin, a method may be to apply or impregnate the desired portion with molten thermoplastic resin, followed by curing. For example, if the insulating member is a curable resin, a method may be to apply or impregnate the desired portion with curable resin, followed by curing. For example, if the insulating member is an insulating tape, a method may be to affix the insulating tape to the desired portion.

[0086] like Figure 3D As shown, the method of the present disclosure includes: (c) after applying the insulating member, laminating a second current collector layer on the preliminary laminate to form an electrode laminate.

[0087] The method for forming the electrode stack by laminating the second current collector layer on the preliminary stack is not particularly limited. For example, when the second current collector layer is a metal foil, a method of placing the metal foil on the second electrode active material layer in the preliminary stack and applying pressure can be used.

[0088] battery module

[0089] like Figure 4 As shown, the battery module 1 of the present disclosure includes the solid battery 10 of the present disclosure. For the solid battery of the present disclosure, reference can be made to the above description related to the solid battery of the present disclosure.

[0090] 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 less than the thickness of the main body region of the electrode stack. Therefore, for example, in a battery module of the present disclosure including 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 more significant.

[0091] The number of the 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. Figure 4 , although a mode in which the number of solid batteries is two is illustrated, the number of solid batteries in the battery module of the present disclosure is not limited thereto.

Claims

1. A solid battery comprising an electrode stack, wherein: The electrode stack comprises 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 portion. An insulating member is arranged from at least a portion of one inclined surface in the tapered region via an end surface of the electrode stack to at least a portion of the other inclined surface, 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.

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

3. A battery module, wherein: The battery module includes the solid state battery according to claim 1 or 2.

4. A method for manufacturing a solid battery, the method for manufacturing a solid battery according to claim 1, wherein: The manufacturing method of the solid battery includes the following steps: (a) stacking 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 stack having the tapered region at an end portion; (b) applying the insulating member from at least a portion of one inclined surface in the tapered region via the end surface of the preliminary stack to at least a portion of the other inclined surface such that the length of the insulating member in the stacking direction of the electrode stack is less than the thickness of the main region; as well as (c) After applying the insulating member, the second current collector layer is stacked on the preliminary stack to form the electrode stack.

5. The method for manufacturing a solid battery according to claim 4, wherein: The step (a) further includes cutting at least a portion of a region formed by the second electrode active material layer being smaller than the first electrode active material layer in the planar direction of the electrode stack to form the tapered region.

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