Battery

Abstract

To provide a battery in which damage to a laminate film by a current collector tab is suppressed.SOLUTION: In a battery including an electrode body, a plurality of current collector tabs extending from a side surface portion of the electrode body, a current collector terminal connected to the plurality of current collector tabs, and a laminate film for accommodating the electrode body and the plurality of current collector tabs, the current collector tab has a root portion that is an end portion on the electrode body side, a connection portion for connecting to the current collector terminal, and an intermediate portion connecting the root portion and the connection portion. The plurality of current collector tabs have a laminated connection portion in which the connection portions thereof are laminated in a thickness direction. The current collector terminal at least has a first surface, a second surface facing the first surface, and a third surface which connects the first surface and the second surface, and faces the side surface portion of the electrode body. A seal portion of the laminate film is disposed on each of the first surface and the second surface, and the main surface of the laminated connection portion is disposed on the third surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a battery.

Background Art

[0002] A battery such as a lithium ion secondary battery generally includes 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 by an exterior body. The electricity generated in the electrode body is led out from the inside of the exterior body to the outside by a current collecting terminal. For example, Patent Document 1 discloses a stacked or stacked / folded type electrode assembly having a positive electrode / separator / negative electrode structure. Further, FIG. 2 of Patent Document 1 discloses that a plurality of tabs (for example, positive electrode tab 40) are joined in a concentrated form and connected on the main surface of a lead (for example, positive electrode lead 60). Furthermore, Patent Document 1 discloses using a laminate sheet (laminate film) as the exterior body. Similarly, Patent Documents 2 to 4 also disclose using a laminate film as the exterior body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] As shown in FIG. 3 described later, the laminated connection portion W of the current collector tab 20 may be disposed on the main surface (the first surface S1 or the second surface S2) of the current collector terminal 30. In this case, the laminated connection portion W may interfere with the laminate film 40, which may cause damage to the laminate film 40.

[0005] The present disclosure has been made in view of the above circumstances, and the main object thereof is to provide a battery that suppresses damage to the laminate film caused by the current collector tab.

Means for Solving the Problems

[0006] [1] A battery including an electrode body, a plurality of current collector tabs extending from a side surface portion of the electrode body, a current collector terminal connected to the plurality of current collector tabs, and a laminate film housing the electrode body and the plurality of current collector tabs, wherein the current collector tab has a root portion that is an end portion on the electrode body side, a connection portion for connecting to the current collector terminal, and an intermediate portion connecting the root portion and the connection portion, the plurality of current collector tabs each have a laminated connection portion in which the respective connection portions are laminated in the thickness direction, the current collector terminal has at least a first surface, a second surface facing the first surface, and a third surface connecting the first surface and the second surface and facing the side surface portion of the electrode body, seal portions of the laminate film are respectively disposed on the first surface and the second surface, and a main surface of the laminated connection portion is disposed on the third surface.

[0007] [2] In a cross-sectional view of the electrode body in the stacking direction, when the length of the current collector terminal in the normal direction of the third surface is L1 and the length of the third surface in a direction orthogonal to the normal direction is L2, the battery according to [1], wherein L1 and L2 satisfy L1 > L2.

[0008] [3] In a cross-sectional view of the electrode body in the stacking direction, the battery according to [1] or [2], wherein the intermediate portion has a curved structure in which a part of the intermediate portion faces each other.

Advantages of the Invention

[0009] The battery in the present disclosure can achieve the effect of providing a battery that suppresses damage to the laminate film by the current collecting tab.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the battery in the present disclosure will be described in detail with reference to the drawings. Each of the drawings shown below is schematically illustrated, and the size and shape of each part are appropriately exaggerated for easy understanding. Also, the hatching of each part may be omitted as appropriate.

[0012] FIG. 1 is a schematic cross-sectional view illustrating the battery in the present disclosure, and FIG. 2 is an enlarged view obtained by enlarging a part of FIG. 1. The battery 100 shown in FIG. 1 includes an electrode body 10, a plurality of current collecting tabs 20 extending from a side surface portion SS 10 of the electrode body 10, a current collecting terminal 30 connected to the plurality of current collecting tabs 20, and a laminate film 40 that houses the electrode body 10 and the plurality of current collecting tabs 20.

[0013] As shown in FIG. 2, the current collecting tab 20 has a root portion X which is an end portion on the electrode body 10 side, a connection portion Y for connecting to the current collecting terminal 30, and an intermediate portion Z connecting the root portion X and the connection portion Y. Further, the plurality of current collecting tabs 20 each have a laminated connection portion W in which the respective connection portions Y are laminated in the thickness direction (y-axis direction in FIG. 2). The current collecting terminal 30 has at least a first surface S1, a second surface S2 facing the first surface S1, and a third surface S3 connecting the first surface S1 and the second surface S2 and facing the side surface SS 10 of the electrode body 10. Further, as shown in FIG. 1, seal portions SE of the laminate film 40 are respectively disposed on the first surface S1 and the second surface S2 of the current collecting terminal 30. Further, the main surface of the laminated connection portion W is disposed on the third surface S3 of the current collecting terminal 30.

[0014] According to the present disclosure, since the main surface of the laminated connection portion is disposed on the third surface (the surface facing the side surface of the electrode body) of the current collecting terminal, a battery is obtained in which damage to the laminate film due to the current collecting tab is suppressed. For example, as shown in FIG. 3, the laminated connection portion W of the current collecting tab 20 may be disposed on the main surface (the first surface S1 or the second surface S2) of the current collecting terminal 30. In this case, since the laminated connection portion W interferes with the laminate film 40, there is a possibility that the laminate film 40 is damaged. As shown in FIG. 3, when the laminated connection portion W is disposed on the second surface S2 of the current collecting terminal 30, a bulge occurs in a part of the laminate film 40 (the portion where the laminated connection portion W is disposed). For example, when thermal shock stress is applied to the battery 100, stress concentrates on the bulged portion, and there is a possibility that the laminate film 40 is damaged. On the other hand, in the present disclosure, since the main surface of the laminated connection portion is disposed on the third surface (the surface facing the side surface of the electrode body) of the current collecting terminal, no bulge of the laminate film due to the laminated connection portion occurs. As a result, even when thermal shock stress is applied to the battery, it is possible to suppress damage to the laminate film.

[0015] 1. Configuration of the battery The battery in the present disclosure includes an electrode body, a plurality of current collecting tabs extending from a side surface portion of the electrode body, a current collecting terminal connected to the plurality of current collecting tabs, and a laminate film that houses the electrode body and the plurality of current collecting tabs.

[0016] (1) Electrode body The electrode body in the present disclosure generally includes a power generation unit 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 in this order in the thickness direction. The shape of the electrode body is not particularly limited, but for example, it preferably has a top surface portion, a bottom surface portion facing the top surface portion, and four side surface portions connecting the top surface portion and the bottom surface portion. The shape of the top surface portion is not particularly limited, and examples include quadrilaterals such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram. Also, the shape of the top surface portion may be a polygon other than a quadrilateral, or a shape having a curve such as a circle. Also, the shape of the bottom surface portion is the same as that of the top surface portion. The shape of the side surface portion is not particularly limited, and examples include quadrilaterals such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram.

[0017] (2) A plurality of current collecting tabs The plurality of current collecting tabs in the present disclosure are arranged so as to extend from a side surface portion of the electrode body. The "side surface portion of the electrode body" refers to a portion that constitutes the electrode body and whose normal direction intersects the stacking direction of the electrode body. For example, in FIG. 1, the normal direction (y-axis direction) of the side surface portion SS 10 of the electrode body is orthogonal to the stacking direction (x-axis direction) of the electrode body 10. Also, the "stacking direction of the electrode body" refers to the thickness direction of each layer constituting the electrode body.

[0018] As shown in Fig. 2, the current collecting tab 20 has a root portion X which is the end portion on the electrode body 10 side, a connection portion Y for connecting to the current collecting terminal 30, and an intermediate portion Z connecting the root portion X and the connection portion Y. The root portion X is the end portion (boundary portion) on the electrode body 10 side in the current collecting tab 20. The connection portion Y is a portion for connecting to the current collecting terminal 30 and is a portion constituting the laminated connection portion W described later. The intermediate portion Z is a portion connecting the root portion X and the connection portion Y. In the present disclosure, each of the plurality of current collecting tabs has a laminated connection portion in which the respective connection portions are laminated in the thickness direction. In Fig. 2, the respective connection portions Y in the plurality of current collecting tabs 20 are laminated in the thickness direction of the current collecting tab 20, whereby the laminated connection portion W is formed. In the laminated connection portion W, the respective connection portions Y are joined to each other (fixed to each other).

[0019] As shown in Fig. 2, in a cross-sectional view of the electrode body 10 in the stacking direction, it is preferable that the intermediate portion Z has a curved structure (region indicated by a broken line) in which a part of the intermediate portion Z faces each other. In Fig. 2, among the plurality of current collecting tabs 20, the intermediate portion Z of the current collecting tab 20 located on the rightmost side does not have the above-mentioned curved structure because a part of the intermediate portion Z does not face each other, but the intermediate portions Z of the other plurality of current collecting tabs 20 all have a curved structure. Thus, it is preferable that at least one of the intermediate portions Z of the plurality of current collecting tabs 20 has a curved structure. In the curved structure, a part of the opposing intermediate portions Z may be arranged so as to be in direct contact with each other, or may be arranged with a space provided therebetween. Also, as shown in Fig. 2, it is preferable that the intermediate portions Z in the plurality of current collecting tabs 20 are curved in a U shape.

[0020] As shown in Fig. 4, in a cross-sectional view of the electrode body 10 in the stacking direction, the intermediate portion Z does not necessarily have a curved structure in which a part of the intermediate portion Z faces each other. As shown in Fig. 4, the root portion X and the connection portion Y may be connected by a straight intermediate portion Z.

[0021] (3) Current collecting terminal The current collector terminal in the present disclosure has at least a first surface, a second surface facing the first surface, and a third surface connecting the first surface and the second surface and facing the side surface portion of the electrode body. The current collector terminal may have a fourth surface connecting the first surface and the second surface and facing the third surface.

[0022] The first surface and the second surface generally correspond to the main surfaces of the current collector terminal, and their areas are each larger than the area of the third surface. Also, the third surface of the current collector terminal and the side surface portion of the electrode body are arranged to face each other. The distance between the third surface of the current collector terminal and the side surface portion of the electrode body is, for example, 20 mm or less, and may be 15 mm or less.

[0023] As shown in FIG. 1, seal portions SE of the laminate film 40 are respectively arranged on the first surface S1 and the second surface S2 of the current collector terminal 30. The seal portion SE is a portion that imparts sealing performance when the laminate film 40 is fused. In FIG. 1, the current collector terminal 30 is arranged between two opposing seal portions SE. Also, although not particularly shown, the seal portion may be formed by direct contact of the laminate films with each other, or the seal portion may be formed by arranging the laminate films via a resin layer. Also, the third surface of the current collector terminal is generally located closer to the electrode body side than the seal portion.

[0024] As shown in FIGS. 1 and 2, it is preferable that the main surface of the laminated connection portion W is arranged on the third surface S3 of the current collector terminal 30. The "main surface of the laminated connection portion W" refers to the surface that constitutes the laminated connection portion W and whose normal direction coincides with the thickness direction of the connection portion Y. The main surface of the laminated connection portion W may be arranged in direct contact with the third surface S3, or may be arranged via another member (for example, a conductive layer). The third surface S3 of the current collector terminal 30 and the laminated connection portion W are generally joined (fixed to each other). On the other hand, in the present disclosure, generally, the current collector tabs 20 are not arranged on the first surface S1 and the second surface S2 of the current collector terminal 30.

[0025] As shown in Fig. 1, in a cross-sectional view of the electrode body 10 in the stacking direction, the length of the current collecting terminal 30 in the normal direction of the third surface S3 is defined as L1, and the length of the third surface S3 in the direction orthogonal to the normal direction is defined as L2. Although not particularly shown, the length of the current collecting terminal 30 in the depth direction in Fig. 1 is defined as L3. Further, as shown in Fig. 1, the length of the electrode body 10 in the stacking direction (x-axis direction) of the electrode body 10 is defined as L4.

[0026] It is preferable that L1 and L2 satisfy L1 > L2. The ratio of L1 to L2 (L1 / L2) may be, for example, 2 or more, may be 5 or more, or may be 10 or more. Also, it is preferable that L2 and L3 satisfy L3 > L2. The ratio of L3 to L2 (L3 / L2) may be, for example, 2 or more, may be 5 or more, or may be 10 or more. Further, the ratio of L2 to L4 (L2 / L4) may be, for example, 0.75 or less, may be 0.5 or less, or may be 0.3 or less. On the other hand, L2 / L4 is, for example, 0.1 or more. The length of L2 is, for example, 0.1 mm or more and 10 mm or less, and may be 0.4 mm or more and 5 mm or less.

[0027] 2. Battery members The battery in the present disclosure includes at least an electrode body, a current collecting tab, a current collecting terminal, and a laminate film.

[0028] The electrode body in the present disclosure usually includes a power generation unit 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 in this order in the thickness direction. The electrode body usually has a plurality of power generation units stacked in the thickness direction. For example, the electrode body 10 shown in Fig. 5 has a plurality of power generation units U stacked in the thickness direction (x-axis direction). Each power generation unit U has a positive electrode current collector 4, a positive electrode active material layer 1, an electrolyte layer 3, a negative electrode active material layer 2, and a negative electrode current collector 5 in this order in the thickness direction (x-axis direction). Also, adjacent power generation units U share one negative electrode current collector 5.

[0029] 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 oxides such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2. Examples of the conductive material include carbon materials. The electrolyte may be a solid electrolyte or a liquid electrolyte (electrolyte solution). 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. Examples of the binder include rubber-based binders and fluoride-based binders.

[0030] 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, and oxide active materials such as Li4Ti5O 12 etc. The conductive material, electrolyte, and binder are the same as those described above. Further, 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.

[0031] The positive electrode current collector conducts current collection for the positive electrode active material layer. Examples of the material of the positive electrode current collector include metals such as aluminum, SUS, and nickel. Examples of the shape of the positive electrode current collector include a foil shape. The negative electrode current collector conducts current collection for the negative electrode active material layer. Examples of the material of the negative electrode current collector include metals such as copper, SUS, and nickel. Examples of the shape of the negative electrode current collector include a foil shape.

[0032] The battery in the present disclosure has a positive electrode tab and a negative electrode tab as current collection tabs. As shown in FIG. 5, the positive electrode tab 4t is located on the side surface SS of the electrode body 10 10It extends in a direction intersecting with the stacking direction (x-axis direction) of the electrode body. Further, as shown in FIG. 5, the positive electrode tab 4t may be continuously formed from the positive electrode active material layer 1. When observed from the stacking direction (x-axis direction) of the electrode body, the positive electrode tab 4t is disposed at a position not overlapping with the positive electrode active material layer 1. Also, in FIG. 5, the negative electrode tab 5t extends from a side surface portion of the electrode body 10 in a direction intersecting with the stacking direction (x-axis direction) of the electrode body. Since the details of the negative electrode tab are the same as those of the positive electrode tab, the description here is omitted. As shown in FIG. 5, the positive electrode tab 4t may extend from one side surface portion of the electrode body 10, and the negative electrode tab 5t may extend from the other side surface portion of the electrode body 10 (both tab structure). On the other hand, although not particularly shown, the positive electrode tab 4t and the negative electrode tab 5t may extend from the same side surface portion of the electrode body 10 (single tab structure).

[0033] The current collector terminal in the present disclosure is electrically connected to the current collecting tab in the electrode body. Examples of the shape of the current collector terminal include a plate shape. Examples of the shape of the main surface of the current collector terminal include quadrilaterals such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram. Examples of the material of the current collector terminal include metals such as aluminum and SUS.

[0034] The laminate film in the present disclosure has at least a structure in which a heat-sealing layer and a metal layer are laminated. Further, the laminate film may have a heat-sealing layer, a metal layer, and a resin layer in this order along the thickness direction. Examples of the material of the heat-sealing layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of the material of the metal layer include aluminum, aluminum alloy, and stainless steel. Examples of the material of the resin layer include polyethylene terephthalate (PET) and nylon. The thickness of the heat-sealing layer is, for example, 40 μm or more and 100 μm or less. The thickness of the metal layer is, for example, 30 μm or more and 60 μm or less. The thickness of the 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. The laminate film may be embossed for housing the electrode body.

[0035] The battery in the present disclosure is typically a lithium-ion secondary battery. Examples of the applications of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline vehicles, and diesel vehicles. In particular, it is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or battery electric vehicles (BEVs). Further, the battery in the present disclosure may be used as a power source for moving bodies other than vehicles (e.g., railways, ships, and aircraft), and may also be used as a power source for electrical products such as information processing devices.

[0036] 3. Method for manufacturing the battery The method for manufacturing the battery in the present disclosure is not particularly limited as long as it can manufacture the above-described battery. FIG. 6 is a schematic perspective view illustrating the method for manufacturing the battery in the present disclosure. First, as shown in FIG. 6(a), negative electrode active material layers 2 are formed on both surfaces of a negative electrode current collector 5, respectively. Examples of the method for forming the negative electrode active material layer include a method of applying a slurry containing the material of the negative electrode active material layer onto the negative electrode current collector and drying it. Next, as shown in FIG. 6(b), an electrolyte layer (not shown), a positive electrode active material layer (not shown), and a positive electrode current collector 4 are disposed on the two negative electrode active material layers 2, respectively, to obtain a laminate α.

[0037] Thereafter, as shown in FIG. 6(c), a plurality of laminates α are laminated in the lamination direction D L to produce a laminate β. Next, as shown in FIG. 6(d), the tip of the positive electrode tab 4t is joined to produce a laminated connection portion W, and the laminated connection portion W is joined to the third surface S3 of the current collecting terminal 30. Examples of the method for producing the laminated connection portion W include a method using welding such as laser welding and electron beam welding, a method using a conductive paste, and a method using solder. The method of joining the laminated connection portion W and the third surface S3 of the current collecting terminal 30 is the same as the method for producing the laminated connection portion W. Next, as shown in FIG. 6(e), the normal directions of the main surfaces of the first surface S1 and the second surface S2 of the current collecting terminal 30 are in the lamination direction D LRotate the current collector terminal 30 so as to be parallel thereto. Although not particularly shown, the current collector terminal is similarly joined to the negative electrode tab. Thereafter, the obtained member is sealed using a laminate film to obtain a battery.

[0038] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits the same operational effects is included in the technical scope of the present disclosure.

Explanation of Reference Numerals

[0039] 1... positive electrode 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 collection tab 30... current collector terminal 40... laminate film 100... battery

Claims

1. An electrode body, a plurality of current collecting tabs extending from a side surface portion of the electrode body, a current collecting terminal connected to the plurality of current collecting tabs, a laminate film housing the electrode body and the plurality of current collecting tabs, A battery having, The current collecting tab has a root portion that is an end portion on the electrode body side, a connection portion for connecting to the current collecting terminal, and an intermediate portion connecting the root portion and the connection portion. Each of the plurality of current collecting tabs has a laminated connection portion in which the respective connection portions are laminated in the thickness direction. The current collecting terminal has at least a first surface, a second surface facing the first surface, and a third surface connecting the first surface and the second surface and facing the side surface portion of the electrode body. Sealing portions of the laminate film are disposed on the first surface and the second surface, respectively. A main surface of the laminated connection portion is disposed on the third surface. In a cross-sectional view of the electrode body in the stacking direction, the intermediate portion has a curved structure in which a part of the intermediate portion faces each other. When the stacking direction of the electrode body is the x-axis direction, the intermediate portion is connected to the connection portion in a state of extending in the x-axis direction on the connection portion side. A battery.

2. In a cross-sectional view in the stacking direction of the electrode body, let the length of the current collector terminal in the normal direction of the third surface be L １ and let the length of the third surface in the direction orthogonal to the normal direction be L ２ When this is the case, the L １ and the L ２ are such that L １ > L ２ is satisfied. The battery according to claim 1

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