Battery

Abstract

To provide a battery having good joining between a tab and a collector terminal.SOLUTION: In a present disclosure, provided is a battery including a power generation element. The power generation element includes: a first active material layer; a second active material layer; an electrolyte layer disposed between the first active material layer and the second active material layer; a first collector collecting current for the first active material layer; and a second collector collecting current for the second active material layer. The first collector has a first tab. The battery includes a first collector terminal electrically connected to the first tab. In a plan view in a thickness direction of the power generation element, the first collector terminal has a base and a projection projecting from the base to a side of the first tab. The first tab has a slit extending from an edge T1 on a side of the first collector terminal to a side of the first active material layer. The slit and the projection are in contact with each other, and the first tab has a buckling including the slit.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A battery such as a lithium ion secondary battery usually has a positive electrode collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode collector. The positive electrode collector usually has a positive electrode tab, which is electrically connected to a positive electrode collector terminal. On the other hand, the negative electrode collector usually has a negative electrode tab, which is electrically connected to a negative electrode collector terminal. Patent Document 1 discloses a joining method for joining a laminated structure in which a plurality of metal foils and a plurality of insulating films are laminated, to a metal plate installed at an end of the laminated structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-129328 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the thickness of the tab is thin and therefore prone to unintended deformation, which may cause poor bonding between the tab and the current collecting terminal.

[0005] The present disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide a battery in which the tab and the current collecting terminal are well joined. [Means for solving the problem]

[0006] The present disclosure provides a battery including a power generating element, the power generating element including a first active material layer, a second active material layer, an electrolyte layer disposed between the first active material layer and the second active material layer, a first current collector that collects current from the first active material layer, and a second current collector that collects current from the second active material layer, the first current collector having a first tab, the battery including a first current collecting terminal electrically connected to the first tab, when viewed in a plane in the thickness direction of the power generating element, the first current collecting terminal having a base and a protruding portion that protrudes from the base toward the first tab, the first tab having a slit extending from an end T1 on the first current collecting terminal side toward the first active material layer side, the slit and the protruding portion being in contact, and the first tab having a buckling portion including the slit.

[0007] According to the present disclosure, by providing a slit in the tab and further providing a buckling portion including the slit, a battery can be obtained in which the tab and the current collecting terminal are well joined.

[0008] In the above disclosure, when viewed in a plan view in the thickness direction of the power generating element, the end T S The end T of the first active material layer F It may be located further outwards.

[0009] In the above disclosure, the first current collecting terminal may have a plurality of the protrusions.

[0010] In the above disclosure, the first tab may have a plurality of the slits for one of the protruding portions.

[0011] In the above disclosure, the power generating element may be a sheet type. Effect of the Invention

[0012] The battery of the present disclosure has the advantage that the tab and the current collecting terminal are well joined. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic perspective view illustrating a battery according to the present disclosure. [Diagram 2] 2 is a cross-sectional view taken along the line AA in FIG. [Diagram 3] 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 2 is a schematic plan view illustrating a first tab and a first current collecting terminal in the present disclosure. [Diagram 5] 3A and 3B are a schematic plan view and a schematic cross-sectional view illustrating a first tab in the present disclosure. [Figure 6] FIG. 2 is a schematic plan view illustrating a first tab in the present disclosure. [Figure 7] 3 is a schematic cross-sectional view illustrating a protrusion according to the present disclosure. FIG. [Figure 8] FIG. 2 is a schematic perspective view illustrating a first current collecting terminal in the present disclosure. [Figure 9] 1 is a schematic perspective view illustrating a method for manufacturing a battery according to the present disclosure. [Figure 10] 1 is a schematic perspective view illustrating a method for manufacturing a battery according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The battery of the present disclosure will be described in detail below 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" simply refers to 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, unless otherwise specified.

[0015] Fig. 1 is a schematic perspective view illustrating a battery according to the present disclosure. Fig. 2 is an AA cross-sectional view in Fig. 1, specifically a cross-sectional view of the z-axis cross-section of the power generating element observed in the +x direction. Fig. 3 is a BB cross-sectional view in Fig. 1, specifically a cross-sectional view of the x-axis cross-section of the first current collecting terminal observed in the -z direction.

[0016] The battery 100 shown in FIG. 1 includes a plurality of power generating elements 10. As shown in FIG. 2, the power generating element 10 includes a first active material layer 1, a second active material layer 2, an electrolyte layer 3 disposed between the first active material layer 1 and the second active material layer 2, a first current collector 4 that collects current from the first active material layer 1, and a second current collector 5 that collects current from the second active material layer 2. The four power generating elements 10 shown in FIG. 2 are connected in parallel with each other. Also, as shown in FIG. 1, the first current collector 4 has a first tab 4t.

[0017] The battery 100 shown in FIG. 1 includes a first current collecting terminal 20a electrically connected to a first tab 4t. For convenience, FIG. 1 shows a state before the first tab 4t and the first current collecting terminal 20a are electrically connected. As shown in FIG. 3, the first current collecting terminal 20a has a base portion 21 and a protruding portion 22 protruding from the base portion 21 toward the first tab (not shown). As shown in FIG. 4(a), the first tab 4t has a slit S extending from an end portion T1 on the first current collecting terminal 20a side to the first active material layer 1 side. As shown in FIG. 4(b), the slit S and the protruding portion 22 are in contact with each other, and the first tab 4t has a buckling portion B including the slit S.

[0018] FIG. 5(a) is a schematic plan view illustrating a first tab in the present disclosure, showing the first tab before it is electrically connected to the first current collecting terminal. FIG. 5(b) is a cross-sectional view taken along line AA in FIG. 5(a). Meanwhile, FIG. 5(c) is a schematic plan view illustrating a first tab in the present disclosure, showing the first tab after it is electrically connected to the first current collecting terminal. FIG. 5(d) is a cross-sectional view taken along line AA in FIG. 5(c). The first tab 4t shown in FIGS. 5(a) and (b) has two slits S, and the side s1 located between the two slits S comes into contact with a protruding portion (not shown) and moves toward the first active material layer 1. As a result, as shown in FIGS. 5(c) and (d), a part of the first tab 4t is moved in the thickness direction D. T The plate buckles so that it deforms out of plane, and a buckling portion B having a slit S is formed.

[0019] According to the present disclosure, a battery is obtained in which the tab and the current collecting terminal are well bonded by providing a slit in the tab and further providing a buckling portion including the slit. As described above, the tab is generally thin and therefore prone to unintended deformation. When unintended deformation occurs, there is a possibility that the tab and the current collecting terminal may be poorly bonded. For example, when unintended deformation occurs at the base of the tab, the deformed tab may come into contact with a member of a different polarity, causing a short circuit. In particular, when the current collecting terminal and the tab are bonded by pressing a current collecting terminal having a protruding portion against the tab, the current collecting terminal and the tab can be firmly bonded, but the protruding portion makes it easy for the tab to deform. In response to this, in the present disclosure, a slit is provided in the tab. As a result, when the current collecting terminal having a protruding portion is pressed against the tab, a buckling portion including the slit is formed. In this way, by providing a slit in the tab and actively providing a portion where buckling occurs, it is possible to control the deformation of the tab. As a result, a battery is obtained in which the tab and the current collecting terminal are well bonded.

[0020] 1. Power generation elements The power generating element in the present disclosure has a first active material layer, a second active material layer, an electrolyte layer disposed between the first active material layer and the second active material layer, a first current collector that collects current from the first active material layer, and a second current collector that collects current from the second active material layer.

[0021] In the present disclosure, when the first active material layer is a positive electrode active material layer, the first current collector is a positive electrode current collector, the second active material layer is a negative electrode active material layer, and the second current collector is a negative electrode current collector. Conversely, when the first active material layer is a negative electrode active material layer, the first current collector is a negative electrode current collector, the second active material layer is a positive electrode active material layer, and the second current collector is a positive electrode current collector.

[0022] (1) First current collector The first current collector in the present disclosure is electrically connected to the first active material layer and collects current from the first active material layer. The first current collector is disposed, for example, on the surface of the first active material layer opposite the electrolyte layer. As shown in FIG. 4(a), the first current collector 4 has a first tab 4t. The first tab 4t is disposed in a region that does not overlap with the first active material layer 1 in the thickness direction (z-axis direction) of the power generating element 10. For example, when the first active material layer 1 is formed by a coating method, the first tab 4t is an uncoated portion where the first active material layer is not formed.

[0023] As shown in FIG. 4(a), the first tab 4t is located at the end T F The extending direction D1 is the thickness direction D of the power generating element 10. T The extension direction D1 in FIG. 4(a) intersects with the thickness direction D T The direction D1 of the first tab 4t and the thickness direction D of the power generating element 10 are perpendicular to each other. T The angle (acute angle side) with respect to the surface is, for example, 60° or more and 90° or less, and may be, for example, 75° or more and 90° or less, or may be, for example, 80° or more and 90° or less.

[0024] As shown in FIG. 4(a), when viewed in plan in the thickness direction (z-axis direction) of the power generating element 10, the first tab 4t has a slit S extending from an end T1 on the first current collecting terminal side to the first active material layer 1 side. The shape of the slit S in plan view may be linear or curved. In addition, the end of the slit S on the first active material layer 1 side is referred to as end T S From end T1 to end T SThe length to L S Let us assume that L S is, for example, 0.1 mm or more, and may be 1 mm or more. S is, for example, 30 mm or less, and may be 5 mm or less.

[0025] As shown in FIG. 4(a), the end T S is the end T F It is preferable that the end T S and end T F It is preferable that there is an area where the slit S does not exist between the end T and the first tab. This is because deformation of the base of the first tab can be suppressed. S From end T F The length (shortest length) to L SF Let us assume that L SF is, for example, 0.1 mm or more, and may be 1 mm or more. SF is, for example, 30 mm or less, and may be 5 mm or less.

[0026] Also, as shown in FIG. 4(b), the slits S and the protrusion 22 are usually in contact with each other. The first tab 4t shown in FIG. 4(b) has two slits S for one protrusion 22. In this manner, the first tab 4t may have a plurality of slits S for one protrusion 22. By forming a plurality of slits S for one protrusion 22, the buckling portion is formed stably. On the other hand, as shown in FIG. 6(a), the first tab 4t may have only one slit S for one protrusion 22. In this case, there is an advantage that the manufacturing process can be simplified.

[0027] As shown in FIG. 6(a), the extension direction of the slit S is D S The extension direction D S The angle (acute angle side) between the extension direction D1 (extension direction of the first tab 4t) and the end T1 is, for example, 0° or more and 45° or less, and may be 0° or more and 30° or less. Also, as shown in FIG. 6(b), the first tab 4t has multiple slits S for one protrusion 22, and the distance between adjacent slits S is from end T1 to end T S4(a), the first tab 4t has a plurality of slits S for one protrusion 22, and the distance between adjacent slits S is preferably from end T1 to end T S The term "same" means that the length from the end T1 to the end T S This means that the difference between the maximum and minimum distances between adjacent slits S is 1 mm or less.

[0028] The first current collector in the present disclosure is a positive electrode current collector or a negative electrode current collector. Examples of the material of the positive electrode current collector include metals such as aluminum, SUS, and nickel. Examples of the material of the negative electrode current collector include metals such as copper, SUS, and nickel. Examples of the shape of the first current collector include a foil shape and a mesh shape. The thickness of the first current collector is, for example, 200 μm or less, and may be 20 μm or less. On the other hand, the thickness of the first current collector is, for example, 5 μm or more.

[0029] (2) Second current collector The second current collector in the present disclosure is electrically connected to the second active material layer and collects current from the second active material layer. The second current collector is disposed, for example, on the surface of the second active material layer opposite the electrolyte layer. As shown in FIG. 1, the second current collector 5 may have a second tab 5t. The second tab is usually disposed in a region that does not overlap with the second active material layer in the thickness direction of the power generating element.

[0030] As shown in FIG. 1, the second tab 5t may have a slit extending from the end T2 on the second current collector terminal 20b side to the second active material layer (not shown). A preferred embodiment of the second tab is similar to the preferred embodiment of the first tab described above, and therefore will not be described here. As shown in FIG. 1, the second tab 5t and the first tab 4t may be disposed on opposing sides of the power generating element 10. Such a structure is called a double tab structure. On the other hand, although not particularly shown, the second tab and the first tab may be disposed on the same side of the power generating element. Such a structure is called a single tab structure.

[0031] (3) First active material layer, second active material layer, and electrolyte layer The first active material layer in the present disclosure is a positive electrode active material layer or a negative electrode active material layer, and the second active material layer in the present disclosure has a polarity opposite to that of the first active material layer.

[0032] 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.

[0033] 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. The liquid electrolyte (electrolytic solution) contains, for example, a supporting salt such as LiPF6 and a solvent such as a carbonate-based solvent. Examples of the binder include a rubber-based binder and a fluoride-based binder.

[0034] 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.

[0035] 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.

[0036] (4) Power generation elements The power generating element in the present disclosure may be of a sheet type or a wound type. In the case of a sheet type, the tab is structurally prone to unintended deformation, but in the present disclosure, a slit is provided in the tab and a buckling portion is further provided, thereby suppressing unintended deformation of the tab. On the other hand, in the case of a wound type, the first tab is wound in a spiral shape, and the rigidity of the first tab is increased by the arc portion of the spiral. In contrast, for example, when the power generating element is a flat wound type (a wound type power generating element flattened by pressing), the first tab is likely to be deformed at the flat portion. In this respect, the flat wound type power generating element exhibits the effects of the present disclosure more than a wound type power generating element in which the first tab is wound in a spiral shape. It is preferable that the battery includes a plurality of power generating elements. In addition, when the battery has a plurality of power generating elements, the plurality of first tabs may be electrically connected to the first current collecting terminal without being joined to each other.

[0037] 2. Current collector terminal The battery according to the present disclosure includes a first current collector terminal electrically connected to the first tab, and a second current collector terminal electrically connected to the second tab. The material of these current collector terminals is not particularly limited, but may be a metal such as SUS.

[0038] As shown in Fig. 4(a), when viewed in a plan view in the thickness direction (z-axis direction) of the power generating element 10, the first current collecting terminal 20a has a base portion 21 and a protruding portion 22 that protrudes from the base portion 21 toward the first tab 4t. As shown in Fig. 4(b), the protruding portion 22 and the first tab 4t are in contact. The base portion 21 and the first tab 4t may or may not be in contact with each other, but the former is preferable because this reduces internal resistance.

[0039] The first current collecting terminal has at least a base and a protruding portion. The planar shape of the base (the outer edge shape when the base is viewed in a planar manner in the thickness direction) is, for example, a rectangle such as a rectangle or a square. Meanwhile, the first current collecting terminal may have only one protruding portion, or may have multiple protruding portions. In the latter case, it is preferable that the multiple protruding portions are regularly arranged at a constant pitch. Also, the protruding portion has a shape that protrudes from the base to the first tab side. Here, FIG. 7 is a schematic cross-sectional view illustrating an example of the first current collecting terminal, similar to FIG. 3. As shown in FIG. 7(a), the height (length from the base 21) of the protruding portion 22 is H, and the width (length in a direction perpendicular to the height H) of the protruding portion 22 is W. H may be, for example, 0.1 mm or more, and may be 1 mm or more. Meanwhile, H may be, for example, 50 mm or less, and may be 30 mm or less. Also, W may be, for example, 1 mm or more, and may be 5 mm or more. On the other hand, W is, for example, 50 mm or less, and may be 10 mm or less.

[0040] As shown in FIG. 7(a), the protrusion 22 may have a flat top surface t. The top surface t contacts a first tab (not shown). The width of the top surface t is, for example, 0.5 times or more, 0.7 times or more, or 0.9 times or more, the above W. On the other hand, the width of the top surface t is, for example, 1 time or less the above W. Also, as shown in FIG. 7(b), the protrusion 22 may have a curved surface.

[0041] The first current collecting terminal may have one or more walls arranged to share the side of the base. Providing the walls increases the rigidity of the first current collecting terminal. Providing the walls also makes it possible to suppress the occurrence of a short circuit, for example, even if an unintended deformation occurs in the tab. For example, the first current collecting terminal 20a shown in FIG. 8(a) has a wall 23 and a wall 24 arranged to share the long side of the base 21. For example, the wall 24 constitutes the top surface of the first current collecting terminal 20a, and the wall 23 constitutes the bottom surface of the first current collecting terminal 20a. Furthermore, the first current collecting terminal 20a shown in FIG. 8(a) has a wall 25 and a wall 26 arranged to share the short side of the base 21. For example, the wall 25 and the wall 26 each constitute a side surface of the first current collecting terminal 20a. On the other hand, as shown in FIG. 8(b), the first current collecting terminal 20a may have only the base 21 and the protruding portion 22. Furthermore, as shown in FIG. 8( c ), the first current collecting terminal 20 a may have a groove 27 corresponding to the protrusion 22 .

[0042] On the other hand, the second current collecting terminal may have a base and a protruding portion protruding from the base toward the second tab, similarly to the first current collecting terminal. Furthermore, the slit in the second tab and the protruding portion in the second current collecting terminal may be in contact with each other, and the second tab may have a buckling portion including the slit. The preferred aspects of the second current collecting terminal are the same as those of the second current collecting terminal tab described above, and therefore will not be described here.

[0043] 3.Battery The battery in the present disclosure may include an exterior body that houses a power generating element. Examples of the exterior body include a laminate-type exterior body and a case-type exterior body. The type of the battery in the present disclosure is not particularly limited, but is typically a lithium-ion secondary battery. The use of the battery in the present disclosure is not particularly limited, but may be, for example, a power source for a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), a gasoline-powered vehicle, or a diesel-powered vehicle. In particular, it is preferably used as a driving power source for a hybrid electric vehicle or an electric vehicle. The battery in the present disclosure may be used as a power source for a moving body other than a vehicle (for example, a train, a ship, or an aircraft), or may be used as a power source for an electrical product such as an information processing device.

[0044] The manufacturing method of the battery in the present disclosure is not particularly limited. FIG. 9 and FIG. 10 are schematic perspective views illustrating the manufacturing method of the battery in the present disclosure. First, as shown in FIG. 9(a), the second active material layer 2 is formed on both sides of the second current collector 5. For example, a method of forming the second active material layer includes a method of applying a slurry containing the material of the second active material layer onto the second current collector and drying it. Next, as shown in FIG. 9(b), a slit S is formed in the second tab 5t. For example, a method of forming the slit S includes cutting with a blade and cutting with a laser. Next, as shown in FIG. 9(c), an electrolyte layer (not shown), a first active material layer (not shown), and a first current collector 4 are arranged on the two second active material layers 2, respectively, to obtain a laminate α. Regarding the slit S in the first tab 4t, the slit S may be formed in advance in the first tab 4t before arranging the first current collector 4, or the slit S may be formed in the first tab 4t after arranging the first current collector 4.

[0045] Then, as shown in FIG. 9(d), the two laminates α are stacked in the thickness direction D T9(e), the first current collecting terminal 20a is pushed into the first tab 4t having the slit S from the side (side of the power generating element) of the laminate β, and then the laminate β and the first current collecting terminal 20a are joined to produce the laminate γ. Examples of a method for joining the laminate β and the first current collecting terminal 20a include a method using welding such as laser welding and electron beam welding, a method using a conductive paste, and a method using solder. Next, as shown in FIG. 10(a), the laminate γ and the second current collecting terminal 20b are joined in the same manner as the first current collecting terminal 20a to produce the laminate δ. Furthermore, the laminate δ is housed in the exterior body 30. Next, as shown in FIG. 10(b), the gap between the first current collecting terminal 20a and the exterior body 30 is sealed, and similarly, the gap between the second current collecting terminal 20b and the exterior body 30 is sealed. Examples of sealing methods include crimping and lamination. In this manner, the battery 100 is obtained.

[0046] 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]

[0047] 1...First active material layer 2...Second active material layer 3...Electrolyte layer 4…First current collector 4t…1st tab 5…Second current collector 5t…Second tab 10…Power generation element 20a…1st current collector terminal 20b…Second current collector terminal 100…Battery

Claims

1. A battery including a power generating element, the power generating element includes a first active material layer, a second active material layer, an electrolyte layer disposed between the first active material layer and the second active material layer, a first current collector that collects current from the first active material layer, and a second current collector that collects current from the second active material layer; the first current collector has a first tab; the battery includes a first current collecting terminal electrically connected to the first tab; When viewed in a plan view in a thickness direction of the power-generating element, the first current collecting terminal has a base portion and a protruding portion that protrudes from the base portion toward the first tab, The first tab is an end T １ a slit extending from the first active material layer side to the second active material layer side, The first tab has a plurality of the slits for one of the protruding portions, the first tab has a buckling portion including the plurality of slits, the buckling portion and the protruding portion are in contact with each other, a battery in which, when viewed in a plan view in a thickness direction of the power-generating element, an end of the buckling portion on the first current collecting terminal side is located closer to the first active material layer than the end T 1 of the first tab.

2. A battery as described in claim 1, wherein when viewed in a plane in the thickness direction of the power generating element and the extension direction of the first tab is D1, the distance between adjacent slits in a direction perpendicular to the extension direction D1 increases along a direction from the end of the buckling portion on the first collector terminal side toward the first active material layer side.

3. A battery as described in claim 1 or claim 2, wherein the base portion of the first collecting terminal and the first tab are in contact.

4. When the extension direction of the first tab is D 1 , The battery according to any one of claims 1 to 3, wherein the first collector terminal has a pair of wall portions arranged to share a long side of the base portion and protruding from the protrusion in the extension direction D1, and a pair of wall portions arranged to share a short side of the base portion and protruding from the protrusion in the extension direction D1.

Images