Battery

Abstract

To provide a battery in which entry of moisture can be suppressed.SOLUTION: A battery includes an electrode body, a current collecting terminal disposed on a side surface part of the electrode body, and a laminate film covering the electrode body and the current collecting terminal. The electrode body includes a current collecting tab. The current collecting tab and the current collecting terminal are in electric connection. The laminate film includes a metal layer, and an internal resin layer existing on the current collecting terminal side relative to the metal layer. The current collecting terminal includes a base part and a porous part existing on the laminate film side relative to the base part. Between the base part and the metal layer, a resin layer including the internal resin layer is disposed. The porous part and the resin layer are in contact with each other. The inside of the porous part is filled with at least a part of the resin layer. The object can be achieved by the provision of such a battery.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Batteries such as lithium ion secondary batteries usually include an electrode body having a positive electrode current collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector. The electrode body is sealed in an internal space surrounded by an exterior material, for example. Patent Document 1 discloses a laminated battery including an electrode body, a laminate exterior material, and a tab film, and discloses that the tab film is disposed between the terminal portion of the electrode body and the edge portion of the laminate exterior material. Patent Document 2 discloses a sealed battery in which a rough surface (e.g., an alumite layer) having a plurality of recesses is formed on at least one of the surfaces of an internal terminal and an external terminal, which are stacked with a plating layer interposed therebetween, and a part of the plating layer penetrates into the recesses. Patent Document 3 discloses a nonaqueous electrolyte secondary battery in which a resin terminal holder and a current collector terminal are fixed by thermal caulking, and discloses that the surface of the current collector terminal on the terminal holder side is anodized. Patent Document 4 discloses a bipolar battery having current collectors arranged on both ends of a power generating element along the stacking direction of the bipolar electrodes, and discloses that the outer surfaces of the current collectors are anodized. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-194949 A [Patent Document 2] JP 2020-140887 A [Patent Document 3] JP 2014-154397 A [Patent Document 4] JP 2011-060456 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, Patent Document 1 discloses that a tab film is disposed between the terminal portion (current collector terminal) of the electrode body and the edge portion of the laminate exterior material (laminate film). By providing the tab film, the adhesion between the current collector terminal and the laminate film is improved. On the other hand, moisture easily penetrates into the internal region sealed by the laminate film through the resin layer of the tab film, etc.

[0005] The present disclosure has been made in consideration of the above-mentioned circumstances, and has a primary object to provide a battery capable of suppressing the intrusion of moisture. [Means for solving the problem]

[0006] [1] A battery comprising an electrode body, a current collecting terminal arranged on a side portion of the electrode body, and a laminate film covering the electrode body and the current collecting terminal, wherein the electrode body has a current collecting tab, and the current collecting tab and the current collecting terminal are electrically connected, the laminate film has a metal layer and an inner resin layer located on the current collecting terminal side of the metal layer, the current collecting terminal has a base and a porous portion located on the laminate film side of the base, a resin layer including the inner resin layer is arranged between the base and the metal layer, the porous portion and the resin layer are in contact, and at least a portion of the resin layer is filled inside the porous portion.

[0007] [2] The battery according to [1], wherein the current collecting terminal contains aluminum, and the porous portion is an anodized aluminum portion.

[0008] [3] The battery according to [1] or [2], wherein the electrode body contains a solid electrolyte.

[0009] [4] The battery according to [3], wherein the solid electrolyte is a sulfide solid electrolyte. Effect of the Invention

[0010] The battery according to the present disclosure has an advantage that it is possible to suppress the intrusion of moisture. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a battery according to the present disclosure. [Diagram 2] FIG. 2 is an enlarged view of an area A in FIG. [Diagram 3] FIG. 1 is an explanatory diagram illustrating a problem in the present disclosure. [Figure 4] 1A and 1B are a schematic plan view and a schematic cross-sectional view illustrating an electrode body in the present disclosure. [Diagram 5] FIG. 2 is a schematic cross-sectional view illustrating a portion of a current collecting terminal according to the present disclosure. [Figure 6] FIG. 2 is a schematic perspective view illustrating a current collecting terminal according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Each of the drawings shown below is a schematic illustration, and the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, in this specification, when expressing an aspect in which another member is arranged relative to a certain member, the term "above" or "below" is used, unless otherwise specified, it includes both a case in which another member is arranged directly above or below a certain member so as to be in contact with the certain member, and a case in which another member is arranged above or below a certain member via another member.

[0013] Fig. 1 is a schematic cross-sectional view illustrating a battery according to the present disclosure. The battery 100 shown in Fig. 1 includes an electrode body 10, a current collecting terminal 20 disposed on a side surface of the electrode body 10, and a laminate film 30 that covers the electrode body 10 and the current collecting terminal 20. The electrode body 10 has a current collecting tab T, and the current collecting tab T and the current collecting terminal 20 are electrically connected.

[0014] Fig. 2 is an enlarged view of region A in Fig. 1. As shown in Fig. 2, the laminate film 30 has a metal layer 31 and an inner resin layer 32 located closer to the current collecting terminal 20 than the metal layer 31. On the other hand, the current collecting terminal 20 has a base 21 and a porous portion 22 located closer to the laminate film 30 than the base 21. A resin layer X including the inner resin layer 32 is disposed between the base 21 and the metal layer 31. The porous portion 22 and the resin layer X are in contact with each other, and at least a portion of the resin layer X is filled inside the porous portion 22.

[0015] According to the present disclosure, at least a part of the resin layer is filled inside the porous portion, thereby forming a battery capable of suppressing the intrusion of moisture. As described above, Patent Document 1 discloses that a tab film is disposed between the terminal portion (current collector terminal) of the electrode body and the edge portion of the laminate exterior material (laminate film). By providing the tab film, the adhesion between the current collector terminal and the laminate film is improved. On the other hand, moisture easily invades the internal region sealed by the laminate film through the resin layer such as the tab film.

[0016] 3(a), for example, when the laminate film 30 and the current collecting terminal 20 are welded via a tab film 40, the adhesion between the laminate film 30 and the current collecting terminal 20 is improved. Furthermore, since the metal layer 31 in the laminate film 30 is usually not permeable to moisture, moisture will not penetrate into the interior of the laminate film 30 from the outside, unless damage such as cracks occurs in the metal layer 31.

[0017] On the other hand, the inner resin layer 32 and the tab film 40 in the laminate film 30 have higher moisture permeability than the metal layer 31. T Orthogonal direction D X In the direction D, moisture intrusion occurs. X The moisture intrusion is in the direction D XThe larger the cross-sectional area, the easier it is for moisture to penetrate. In response to this, as shown in FIG. 2, a porous portion 22 is provided in the current collecting terminal 20, and the inside of the porous portion 22 is filled with a resin layer X, so that the moisture permeation in the direction D X Therefore, the cross-sectional area of ​​the resin layer X (the inner resin layer 32) in the battery can be prevented from entering moisture.

[0018] As shown in FIG. 3(b), when the current collecting terminal 20 and the inner resin layer 32 are in contact with each other, the direction D X In this case, the cross-sectional area of ​​the resin layer X (inner resin layer 32) is smaller than when a tab film is used. On the other hand, the adhesion between the current collecting terminal and the laminate film is lower than when a tab film is used. In response to this, as shown in Fig. 2, a porous portion 22 is provided in the current collecting terminal 20, and the inside of the porous portion 22 is filled with the resin layer X, thereby generating an anchor effect and increasing the adhesion between the current collecting terminal 20 and the laminate film 30.

[0019] 1. Battery configuration The battery according to the present disclosure includes at least an electrode body, a current collecting terminal, and a laminate film.

[0020] (1) Electrode body The electrode body in the present disclosure functions as a power generating element of a battery. For example, as shown in Fig. 4, the electrode body 10 has a positive electrode active material layer 1, a negative electrode active material layer 2, an electrolyte layer 3 disposed between the positive electrode active material layer 1 and the negative electrode active material layer 2, a positive electrode current collector 4 that collects current from the positive electrode active material layer 1, and a negative electrode current collector 5 that collects current from the negative electrode active material layer 2. The electrode body 10 shown in Fig. 4 has the positive electrode current collector 4, the positive electrode active material layer 1, the electrolyte layer 3, the negative electrode active material layer 2, and the negative electrode current collector 5 arranged in a thickness direction D T In this order:

[0021] 4, the electrode body 10 may have a top surface portion TS, a bottom surface portion BS facing the top surface portion TS, and four side surface portions SS (a first side surface portion SS1, a second side surface portion SS2, a third side surface portion SS3, and a fourth side surface portion SS4) connecting the top surface portion TS and the bottom surface portion BS. The top surface portion and the bottom surface portion each correspond to a main surface of the electrode body, and the normal direction of the main surface can be defined as the thickness direction.

[0022] The shape of the top surface is not particularly limited, but examples thereof include quadrilaterals such as squares, rectangles, rhombus, trapezoids, and parallelograms. The shape of the top surface may be a polygon other than a quadrilateral, or may be a shape having a curve such as a circle. The shape of the bottom surface is the same as that of the top surface. The shape of the side surface is not particularly limited, but examples thereof include quadrilaterals such as squares, rectangles, rhombus, trapezoids, and parallelograms.

[0023] 4, the electrode body 10 has a positive electrode current collector tab 4t for connection to a positive electrode current collector terminal (not shown) and a negative electrode current collector tab 5t for connection to a negative electrode current collector terminal (not shown). The positive electrode current collector tab 4t extends from a first side surface portion SS1 facing the positive electrode current collector terminal (not shown) in the thickness direction D T The negative electrode current collector tab 5t extends in a direction intersecting with the thickness direction D from the third side surface portion SS3 that faces the negative electrode current collector terminal (not shown). T The slits extend in a direction intersecting the slits.

[0024] (2) Laminate film and current collecting terminal The laminate film in the present disclosure is a member that covers the electrode body and the current collecting terminal. As shown in Fig. 2, the laminate film 30 has a metal layer 31 and an inner resin layer 32 located closer to the current collecting terminal 20 than the metal layer 31. Although not shown, the laminate film may have an outer resin layer on the opposite side of the inner resin layer with respect to the metal layer.

[0025] The current collector terminals in the present disclosure are disposed on the side surfaces of the electrode body. The battery in the present disclosure preferably includes two current collector terminals for one electrode body. For example, as shown in FIG. 1, a pair of current collector terminals 20 (positive electrode current collector terminal 20A and negative electrode current collector terminal 20B) may be disposed to face each other with respect to the electrode body 10. Also, in FIG. 1, the pair of current collector terminals 20 are disposed to face each other in the longitudinal direction of the electrode body 10.

[0026] As shown in FIG. 2, the current collecting terminal 20 has a base 21 and a porous portion 22 located closer to the laminate film 30 than the base 21. The porous portion 22 is a portion having a large number of pores. The large number of pores may be connected three-dimensionally. The average pore size of the pores is, for example, 1 nm or more and 1000 nm or less. It may be 5 nm or more and 500 nm or less. It may be 10 nm or more and 100 nm or less. The average pore size of the pores is determined, for example, by a mercury intrusion porosimeter. It is preferable that the base 21 and the porous portion 22 are formed continuously.

[0027] An example of a method for forming the porous portion is anodizing. Anodizing is a process that utilizes electrochemical oxidation at an anode. An example of anodizing is anodizing. Anodizing is a process that utilizes electrochemical oxidation to form an oxide film (anodic oxide film) on the surface of aluminum. It is preferable that the current collecting terminal in the present disclosure contains aluminum, and the porous portion is an anodized portion. The anodized portion contains aluminum oxide.

[0028] As shown in FIG. 5, a resin layer X including an inner resin layer 32 is disposed between the base 21 of the current collecting terminal 20 and the metal layer 31 of the laminate film 30. As shown in FIG. 5, the resin layer X may be only the inner resin layer 32. The inner resin layer 32 may be a single layer or may be a plurality of layers. Although not shown, another resin layer Y may be disposed between the inner resin layer and the base 21. Even when the resin layer Y is disposed, a battery capable of suppressing the intrusion of moisture can be obtained by using the current collecting terminal having a porous portion, compared to the case where the current collecting terminal does not have a porous portion.

[0029] As shown in FIG. 5, the porous portion 22 and the resin layer X are in contact with each other, and at least a part of the resin layer X is filled in the porous portion 22. A part of the resin layer X may be filled in the porous portion 22, or the entire resin layer X may be filled in the porous portion 22. Here, the thickness of the resin layer X present between the metal layer 31 and the current collecting terminal 20 is T1, and the thickness of the resin layer X filled in the porous portion 22 is T2. T1 may be 0 or may be greater than 0. In the latter case, T1 may be, for example, 10 μm or more, or 20 μm or more. On the other hand, T1 may be, for example, 100 μm or less, 80 μm or less, or 60 μm or less. T2 is usually greater than 0, and may be 50 nm or more, or may be 100 nm or more. On the other hand, T2 may be, for example, 1 μm or less, or 300 nm or less. Also, T1 may be greater than T2. 5, the resin layer X may be filled in a portion of the porous portion 22 on the metal layer 31 side. On the other hand, although not particularly shown, the resin layer X may be filled in the entire porous portion.

[0030] As shown in Fig. 6, the current collecting terminal 20 may have a first surface S1 facing the electrode body and a plurality of surfaces (a second surface S2 to a fifth surface S5) constituting the outer edge of the first surface S1. Furthermore, the current collecting terminal 20 shown in Fig. 6 has a sixth surface S6 facing the first surface S1. The current collecting terminal 20 shown in Fig. 6 has the second surface S2 and the fourth surface S4 as main surfaces.

[0031] 6, when the current collecting terminal 20 has the second surface S2 to the fifth surface S5, it is preferable that the above-mentioned porous portion is formed on at least one of the second surface S2 to the fifth surface S5. The second surface S2 and the fourth surface S4 are each formed such that their normal directions are parallel to the thickness direction D. T The "parallel" means that the angle (acute angle side) between the two directions is 10° or less. The porous portion may be formed only on the second surface S2 and the fourth surface S4. The third surface S3 and the fifth surface S5 each have a normal direction that is parallel to the thickness direction D. T The porous portion may be formed only on the third surface S3 and the fifth surface S5. The third surface S3 and the fifth surface S5 shown in FIG. 6 are perpendicular to the thickness direction D. T The length in the thickness direction D is short (the thickness of the current collecting terminal 20 is small). T The length at may be greater. In addition, the current collecting terminal 20 may have a porous portion formed over the entire surface.

[0032] The current collecting terminal in the present disclosure has a joining region for joining to the current collecting tab. It is preferable that no porous portion is formed in the joining region. For example, when the porous portion is a metal oxide, it is preferable that no porous portion is formed in the joining region from the viewpoint of reducing resistance. For example, when a joining region is formed on the second surface S2 shown in FIG. 6, the porous portion may not be formed in the joining region, and a porous portion may be formed on the outside of the joining region (the side opposite to the electrode body). In this way, the porous portion may be formed in a pattern on one surface. Also, for example, when a joining region is formed on the first surface S1 shown in FIG. 6, the porous portion may not be formed in the joining region, and a porous portion may be formed on at least one of the multiple surfaces (the second surface S2 to the fifth surface S5) constituting the outer edge of the first surface S1. In this case, the porous portion may not be formed at all on the first surface S1.

[0033] 2. Battery components The battery according to the present disclosure comprises an electrode body, a current collecting terminal, and a laminate film.

[0034] (1) Electrode body 4, the electrode body in the present disclosure includes an electrode body 10 having a positive electrode active material layer 1, a negative electrode active material layer 2, an electrolyte layer 3 disposed between the positive electrode active material layer 1 and the negative electrode active material layer 2, a positive electrode current collector 4 that collects current from the positive electrode active material layer 1, and a negative electrode current collector 5 that collects current from the negative electrode active material layer 2. The electrode body 10 may or may not have a bipolar electrode.

[0035] The positive electrode active material layer contains at least a positive electrode active material. The positive electrode active material layer may further contain at least one of a conductive material, an electrolyte, and a binder. Examples of the positive electrode active material include oxide active materials. Examples of the oxide active material include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Examples of the positive electrode active material include rock salt layer type active materials such as O2, spinel type active materials such as LiMn2O4, and olivine type active materials such as LiFePO4. Sulfur (S) may also be used as the positive electrode active material. The positive electrode active material may be, for example, in the form of particles.

[0036] Examples of the conductive material include carbon materials. The electrolyte may be a solid electrolyte or a liquid electrolyte. The solid electrolyte may be an organic solid electrolyte such as a gel electrolyte, or an inorganic solid electrolyte such as an oxide solid electrolyte or a sulfide solid electrolyte. In particular, since the performance of a sulfide solid electrolyte is significantly reduced by moisture, an electrode body containing a sulfide solid electrolyte is required to prevent moisture from entering. In addition, the liquid electrolyte (electrolytic solution) contains, for example, a supporting salt such as LiPF6 and a solvent such as a carbonate-based solvent. In addition, examples of the binder include a rubber-based binder and a fluoride-based binder.

[0037] The negative electrode active material layer contains at least a negative electrode active material. The negative electrode active material layer may further contain at least one of a conductive material, an electrolyte, and a binder. Examples of the negative electrode active material include metal active materials such as Li and Si, carbon active materials such as graphite, Li4Ti5O 12 The oxide active material may be in the form of, for example, particles or foil. The conductive material, electrolyte and binder are the same as those described above.

[0038] The electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer, and contains at least an electrolyte. The electrolyte may be a solid electrolyte or a liquid electrolyte. The electrolyte is the same as that described above. The electrolyte layer may have a separator.

[0039] The positive electrode current collector collects the current from the positive electrode active material layer. Examples of the material for the positive electrode current collector include metals such as aluminum, aluminum alloy, stainless steel, and nickel. Examples of the shape of the positive electrode current collector include a foil shape and a mesh shape. The positive electrode current collector has a positive electrode current collector tab for connecting to a positive electrode current collector terminal. As shown in FIG. 4, the positive electrode current collector tab 4t may be formed continuously from the positive electrode current collector 4. The electrode body 10 is arranged in the thickness direction D T When viewed from the side, the positive electrode current collector tab 4t is disposed at a position not overlapping with the positive electrode active material layer 1.

[0040] The negative electrode current collector collects the current from the negative electrode active material layer. Examples of the material for the negative electrode current collector include metals such as copper, stainless steel, and nickel. Examples of the shape of the negative electrode current collector include a foil shape and a mesh shape. The negative electrode current collector has a negative electrode current collector tab for connecting to a negative electrode current collector terminal. As shown in FIG. 4, the negative electrode current collector tab 5t may be formed continuously from the negative electrode current collector 5. The electrode body 10 is arranged in the thickness direction D T When viewed from the side, the negative electrode current collector tab 5t is disposed at a position not overlapping with the negative electrode active material layer 2.

[0041] (2) Current collector terminal The current collecting terminal in the present disclosure is disposed on the side surface of the electrode body. T When viewed from above, the current collecting terminal may be disposed at a position that does not overlap with the electrode body (excluding the current collecting tab). The battery of the present disclosure typically has a positive electrode current collecting terminal and a negative electrode current collecting terminal as current collecting terminals. The current collecting terminal has a current collecting portion at least in part. The current collecting portion and the electrode body are electrically connected via the current collecting tab. The current collecting terminal may be entirely the current collecting portion, or may be partially the current collecting portion. Examples of materials for the current collecting terminal include metals such as aluminum, aluminum alloys, and stainless steel.

[0042] (3) Laminate film The laminate film in the present disclosure has a metal layer and an inner resin layer located on one side of the metal layer. The laminate film may have an outer resin layer located on the side of the metal layer opposite to the inner resin layer. Examples of materials for the metal layer include aluminum, aluminum alloy, and stainless steel. The thickness of the metal layer is, for example, 30 μm or more and 60 μm or less. Examples of materials for the inner resin layer include thermoplastic resins. Examples of thermoplastic resins include olefin-based resins such as polypropylene (PP) and polyethylene (PE). The thickness of the inner resin layer is, for example, 40 μm or more and 100 μm or less. Examples of materials for the outer resin layer include ester-based resins such as polyethylene terephthalate (PET) and amide-based resins such as nylon. The thickness of the outer 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.

[0043] (4)Battery The battery in the present disclosure is typically a lithium ion secondary battery. The battery in the present disclosure is preferably an all-solid-state battery. The all-solid-state battery is a battery that uses a solid electrolyte (particularly an inorganic solid electrolyte) instead of an electrolytic solution. 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 automobiles, and diesel 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 in the present disclosure may also be used as a power source for moving objects other than vehicles (for example, railways, ships, and aircraft), and may also be used as a power source for electrical products such as information processing devices.

[0044] The method for manufacturing a battery in the present disclosure is not particularly limited. For example, an electrode body and a current collector terminal are connected via a current collector tab, the resulting member is covered with a laminate film, and the laminate film is heat-sealed in a reduced pressure environment to obtain a battery. The inner resin layer of the laminate film is heated to weld to other members such as the current collector terminal. In addition, in the region where the inner resin layers of the laminate film are in contact with each other, the inner resin layers are welded to each other by heating.

[0045] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. [Explanation of symbols]

[0046] 1...Cathode active material layer 2...Negative electrode active material layer 3...Electrolyte layer 4...Positive electrode current collector 5...Negative electrode current collector 10...Electrode body 20...Current collector terminal 30...Laminating film 100...battery

Claims

[Claim 1] An electrode body; A current collecting terminal disposed on a side surface of the electrode body; a laminate film covering the electrode body and the current collecting terminal; A battery comprising: The electrode body has a current collecting tab, the current collecting tab and the current collecting terminal are electrically connected; The laminate film has a metal layer and an inner resin layer located on the current collecting terminal side of the metal layer, The current collecting terminal has a base and a porous portion located closer to the laminate film than the base, a resin layer including the inner resin layer is disposed between the base and the metal layer; the porous portion and the resin layer are in contact with each other, A portion of the resin layer is filled inside the porous portion, The current collecting terminal contains aluminum, the porous portion is an anodized aluminum portion, The electrode body contains a sulfide solid electrolyte, When the thickness of the resin layer present between the metal layer and the current collecting terminal is T 1 and the thickness of the resin layer filled in the porous portion is T 2 , The T 1 is 20 μm or more and 60 μm or less, The T 2 is 100 nm or more and 300 nm or less, The resin layer fills a portion of the porous portion on the metal layer side.

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