Laminated battery

Abstract

The present disclosure provides a laminated battery capable of mitigating the influence caused by a change in pressure inside a laminated film and / or a change in volume of an electrode laminate accompanying charging and discharging of the battery. A laminated battery (1) according to the present disclosure includes an electrode laminate (10), a collector terminal (20) disposed on a side surface portion of the electrode laminate (10), a collector portion (30) electrically connecting an end portion of the electrode laminate and an end portion of the collector terminal, and a laminated film (40) sealing the electrode laminate (10) together with the collector terminal (20). A laminated film (40) in a laminated battery (1) of the present disclosure has a bent portion (41) in a region (R) between an end portion of an electrode laminate and an end portion of a collector terminal.

Description

Technical Field

[0001] The present disclosure relates to laminated batteries. Background Art

[0002] A laminated battery in which an electrode stack is sealed with a laminate film is known. In a laminated battery, the pressure inside the laminate film may abnormally increase due to, for example, vaporization of components constituting the electrode stack.

[0003] In contrast, Patent Document 1 discloses a laminated battery in which, when the internal pressure of an exterior body (laminate film) rises to a predetermined value, the exterior body is stably ruptured to release the internal pressure.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-145145

[0007] Even when the pressure inside the laminate film increases abnormally, it is preferred that the seal portion of the laminate film does not break if the pressure is within an allowable range.

[0008] Furthermore, in laminated batteries, depending on the type of electrode active material used, the volume of the electrode stack may change as the battery charges and discharges. Because the interior of the laminate film is sealed, the pressure within the laminate film may change due to this volume change in the electrode stack. Specifically, the pressure within the laminate film may increase due to expansion of the electrode stack, while the pressure within the laminate film may decrease due to contraction.

[0009] The inventors of this application have discovered that the increase in pressure within the laminate film associated with the expansion of the electrode stack can cause cracking in the laminate film's sealed portion, and that the expansion of the electrode stack itself can damage the laminate film. Furthermore, the inventors of this application have discovered that the decrease in pressure within the laminate film associated with the contraction of the electrode stack can generate tensile stress within the laminate film, potentially causing cracking in the laminate film's sealed portion. Summary of the Invention

[0010] Problems to be solved by the invention

[0011] An object of the present disclosure is to provide a laminated battery capable of alleviating the effects of changes in pressure inside a laminate film and / or changes in volume of an electrode stack accompanying charge and discharge of the battery.

[0012] Means for solving problems

[0013] The inventors of the present application have discovered that the above-mentioned problems can be solved by the following means.

[0014] Method 1

[0015] A laminated battery comprising an electrode stack, a current collecting terminal arranged on a side surface of the electrode stack, a current collecting portion electrically connecting an end portion of the electrode stack to an end portion of the current collecting terminal, and a laminate film sealing the electrode stack together with the current collecting terminal, wherein:

[0016] The laminate film has a bent portion in a region between an end portion of the electrode stack and an end portion of the current collector terminal.

[0017] Method 2

[0018] The laminate battery according to aspect 1, wherein the bent portion has a convex portion that bulges toward the inner side or the outer side of the laminate film.

[0019] Method 3

[0020] The laminate battery according to aspect 1 or 2, wherein a ratio of the height of the bent portion to the thickness of the thinner one of the electrode stack and the current collector terminal is 0.1 or more.

[0021] Method 4

[0022] The laminate battery according to any one of aspects 1 to 3, wherein a distance L from an end of the electrode stack to an end of the current collector terminal is 1 mm or more and 100 mm or less.

[0023] Method 5

[0024] A laminate battery according to any one of methods 1 to 4, wherein a ratio L / T1 of a distance L from an end portion of the electrode stack to an end portion of the collector terminal to a thickness T1 of the electrode stack is greater than or equal to 0.01 and less than or equal to 100, and a ratio L / T2 of a distance L from an end portion of the electrode stack to an end portion of the collector terminal to a thickness T2 of the collector terminal is greater than or equal to 0.001 and less than or equal to 100.

[0025] Effects of the Invention

[0026] According to the present disclosure, it is possible to provide a laminate battery capable of alleviating the effects of changes in pressure inside a laminate film and / or changes in volume of an electrode stack accompanying charge and discharge of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic plan view showing an example of a laminated battery of the present disclosure.

[0028] Figure 2This is a schematic cross-sectional view showing an example of the laminated battery of the present disclosure, with the region R enlarged.

[0029] Figure 3 This is a schematic cross-sectional view showing an example of the laminated battery of the present disclosure, with the region R enlarged.

[0030] Figure 4 This is a schematic cross-sectional view showing an example of the laminated battery of the present disclosure, with the region R enlarged.

[0031] Figure 5 It is a schematic cross-sectional view for explaining the function of the laminated battery of the present disclosure.

[0032] Figure 6 It is a laminated battery of the prior art. Figure 5 Corresponding schematic cross-sectional view.

[0033] Description of Reference Numerals

[0034] 1 Laminated battery

[0035] 10 Electrode stack

[0036] 20 collector terminal

[0037] 30 current collecting part

[0038] 40 Laminated Film

[0039] 41 Bend DETAILED DESCRIPTION

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

[0041] Laminated Battery

[0042] like Figure 1 As shown in the example, the laminated battery 1 (also referred to as a pouch-shaped battery) of the present disclosure includes an electrode stack 10, a current collecting terminal 20 disposed on a side surface of the electrode stack 10, a current collecting portion 30 electrically connecting an end portion of the electrode stack to an end portion of the current collecting terminal, and a laminate film 40 that seals the electrode stack 10 together with the current collecting terminal 20. Figures 2 to 4 As illustrated, the laminate film 40 in the laminate battery 1 of the present disclosure has a bent portion 41 in a region R between an end portion of the electrode stack and an end portion of the current collecting terminal.

[0043] The inventors of the present application believe that one of the reasons why laminated batteries cannot mitigate the effects of changes in pressure inside the laminate film and / or changes in volume of the electrode stack accompanying battery charge and discharge is that Figure 6 As shown in (a), the laminate film does not have any excess length in the region between the end of the electrode stack and the end of the collector terminal, that is, in the region that is not in contact with either the electrode stack or the collector terminal. Figure 6 As exemplified in (b) of FIG. 1 , for example, when the pressure inside the laminated film increases, the sealing portion (at the Figure 6 The sealing portion between the laminate film and the collector terminal in (b) may crack.

[0044] In view of this, the inventors of the present application have discovered that by forming a curved portion 41 in the region R between the end of the electrode stack and the end of the current collector terminal in the laminate film 40, the effects of changes in pressure inside the laminate film and / or changes in volume of the electrode stack accompanying battery charge and discharge can be mitigated. The reason for this is believed to be that, for example, Figure 5 As shown in (a), the laminate film 40 has a surplus length in the region R, thereby having a bent portion 41, so that even if a pressure rise occurs inside the laminate film, as shown in FIG. Figure 5 As shown in (b), the laminate film 40 deforms so that the space formed by the curved portion 41 is flattened, and the volume of the space inside the laminate film increases. This is believed to mitigate the effects of changes in pressure inside the laminate film and / or changes in the volume of the electrode stack accompanying battery charging and discharging.

[0045] In the present disclosure, damage to the laminate film includes, for example, damage caused by increased pressure applied from the electrode stack to the laminate film at the edges and corners where the electrode stack and the laminate film are in contact due to expansion of the electrode stack.

[0046] The laminated battery 1 of the present disclosure includes an electrode stack 10, a current collector terminal 20 disposed on a side surface of the electrode stack 10, a current collector portion 30 electrically connecting an end of the electrode stack to an end of the current collector terminal, and a laminate film 40 that seals the electrode stack 10 together with the current collector terminal 20. It should be noted that, in the present disclosure, the end of the electrode stack refers to the end of the electrode stack facing the current collector terminal. The end of the current collector terminal refers to the end of the current collector terminal facing the electrode stack.

[0047] The laminate film 40 in the laminate battery 1 of the present disclosure has a bent portion 41 in a region R between an end portion of the electrode stack and an end portion of the current collecting terminal.

[0048] The shape of the curved portion 41 is not particularly limited. Figure 2 and3 As illustrated, the bent portion 41 may have a convex portion that protrudes toward the interior of the laminate film 40. This structure can suppress an increase in the thickness of the laminated battery 1 of the present disclosure. Therefore, when a plurality of laminated batteries 1 are stacked and restrained to form a battery module, the bent portion 41 can be prevented from hindering the pressure equalization of the laminated batteries 1.

[0049] It should be noted that Figure 2 This is a schematic cross-sectional view showing an example of the shape of the bent portion 41 when the thickness of the electrode stack 10 is the same as the thickness of the current collector terminal 20 . Figure 3 This is a schematic cross-sectional view showing an example of the shape of the bent portion 41 when the thickness of the current collector terminal 20 is thinner than the thickness of the electrode stack 10 .

[0050] There is no particular limitation on the method for forming the curved portion 41 having a convex portion protruding toward the inner side of the laminate film 40. For example, a method of pre-curving the laminate film 40 and a method of curving the laminate film 40 while sealing the electrode stack 10 with the laminate film 40 while reducing pressure are mentioned.

[0051] like Figure 4 As shown, the curved portion 41 may have a convex portion protruding toward the outside of the laminate film 40. This structure can easily alleviate the effects of pressure drop inside the laminate film and / or shrinkage of the electrode stack accompanying battery discharge.

[0052] There is no particular limitation on the method for forming the curved portion 41 having a convex portion protruding toward the outside of the laminate film 40. For example, there are methods of pre-curving the laminate film 40, and methods of bending the electrode stack 10 by pressing the collector terminal 20 toward the electrode stack 10 after sealing the electrode stack 10 with the laminate film 40 and the collector terminal 20.

[0053] When the bent portion 41 has a convex portion that protrudes toward the inside or outside of the laminate film 40, the convex portion of the bent portion 41 can be formed so as to be located near the middle of the distance L between the end of the electrode stack and the end of the current collector terminal. With this structure, even if there are changes in the pressure within the laminate film and / or changes in the volume of the electrode stack associated with battery charging and discharging, interference between the electrode stack and the current collector terminal and the laminate film can be easily prevented.

[0054] The laminate film 40 may have the curved portion 41 on either the upper or lower side in the thickness direction of the electrode stack 10, or may have the curved portion 41 on both the upper and lower sides in the thickness direction of the electrode stack 10. It should be noted that the upper curved portion is sometimes referred to as 41a, and the lower curved portion is sometimes referred to as 41b.

[0055] The ratio of the height H (mm) of the bent portion to the thickness (mm) of the thinner one of the electrode stack 10 and the collector terminal 20 can be 0.1 or more. For example, when the thickness T2 of the collector terminal is thinner than the thickness T1 of the electrode stack, the above ratio is represented by H / T2. The ratio can be 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, or 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, or 0.4 or less. If the ratio is large, even when the pressure inside the laminate film changes and / or the volume change of the electrode stack accompanying the charge and discharge of the battery is large, their effects can be effectively mitigated. If the ratio is small, the damage of the collector portion 30 caused by the contact between the laminate film and the collector portion will not be excessively suppressed, and the bent portion 41 can be formed more simply.

[0056] It should be noted that the height H of the bent portion refers to the shortest distance from an imaginary straight line connecting the lower side of the end portion constituting the electrode stack and the lower side of the end portion constituting the current collecting terminal at the shortest distance in the laminate film to the top of the convex portion of the lower bent portion 41b (see Figure 2 (b)), or the shortest distance from an imaginary straight line connecting the upper side of the end portion of the electrode stack and the upper side of the end portion of the collector terminal at the shortest distance to the vertex of the convex portion of the upper curved portion 41a.

[0057] When the bent portion 41a and the bent portion 41b are provided on both the upper and lower sides of the electrode stack 10 in the thickness direction and the thickness T1 of the electrode stack is equal to the thickness T2 of the collector terminal, as shown in FIG. Figure 2 As illustrated, the height of the bent portion 41 a may be equal to the height of the bent portion 41 b .

[0058] When the electrode stack 10 has the bent portion 41a and the bent portion 41b on both the upper and lower sides in the thickness direction and the positions of the electrode stack and the current collecting terminal are Figure 3 In the illustrated relationship, where the thickness of the electrode stack T1 > the thickness of the current collector terminal T2 , the height of the bent portion 41a can be less than the height of the bent portion 41b To achieve this structure, the bent portion 41b can be formed on the electrode stack 10 side, and the bent portion 41a can be formed on the current collector terminal 20 side.

[0059] The distance L from the end of the electrode stack to the end of the collector terminal can be greater than 1 mm and less than 100 mm. The distance L can be greater than 2 mm, greater than 5 mm, or greater than 10 mm, and can be less than 50 mm, less than 25 mm, or less than 10 mm. If the distance L is within the above range, the curved portion 41 is easily formed, and as a result, the effects of the present disclosure such as the effects of changes in pressure within the laminate film and / or changes in the volume of the electrode stack accompanying the charging and discharging of the battery are easily mitigated.

[0060] The ratio L / T1 of the distance L from the end of the electrode stack to the end of the current collector terminal relative to the thickness T1 of the electrode stack can be 0.01 or greater and 100 or less, and the ratio L / T2 of the distance L from the end of the electrode stack to the end of the current collector terminal relative to the thickness T2 of the current collector terminal can be 0.001 or greater and 100 or less. The ratio L / T1 can be 0.1 or greater, 0.5 or greater, or 1 or less, 50 or less, 25 or less, 10 or less, 5 or less, or 1 or less. The ratio L / T2 can be 0.01 or greater, 0.05 or greater, or 0.1 or greater, or 10 or less, 5 or less, 1 or less, 0.5 or less, or 0.1 or less. If these ratios are within the above ranges, the curved portion 41 is easily formed, and as a result, the effects of the present disclosure such as mitigating the effects of changes in pressure within the laminate film and / or changes in the volume of the electrode stack associated with battery charging and discharging are easily achieved.

[0061] The thickness T1 of the electrode stack may be 1 mm or more, 2 mm or more, 5 mm or more, or 10 mm or more, and may be 100 mm or less, 50 mm or less, 25 mm or less, or 10 mm or less.

[0062] The ratio T2 / T1 of the thickness T2 of the collector terminal to the thickness T1 of the electrode stack can be greater than 0.1, greater than 0.3, greater than 0.5, greater than 0.6, greater than 0.7 or greater than 0.8, and can be less than 1, less than 0.9, less than 0.8, less than 0.7, less than 0.6 or less than 0.5.

[0063] The laminated battery disclosed herein has been described above in terms of a laminate film having a curved portion in the stacking direction of the electrode stack. However, the location of the curved portion is not particularly limited. For example, the laminate film may have a curved portion in the plane direction of the electrode stack.

[0064] Hereinafter, the elements constituting the laminated battery of the present disclosure will be described.

[0065] <Electrode stack>

[0066] The electrode stack 10 functions as a power generation element of the laminated battery 1. The shape of the electrode stack 10 is not particularly limited, and for example, it may have a top portion, a bottom portion facing the top portion, and four side portions connecting the top portion and the bottom portion. The shape of the top portion is not particularly limited, and for example, quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms can be listed. In addition, the shape of the top portion can be a polygon other than a quadrilateral, or a shape having a curve such as a circle. In addition, the shape of the bottom portion is the same as that of the top portion. The shape of the side portions is not particularly limited, and for example, quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms can be listed.

[0067] The electrode stack 10 may include a negative electrode current collector, a negative electrode active material layer, an electrolyte layer, a positive electrode active material layer, and a positive electrode current collector in this order.

[0068] 〈Current collector terminal〉

[0069] The current collector terminal 20 is disposed on a side surface of the electrode stack 10. The current collector terminal 20 can be disposed on a pair of opposing side surfaces of the electrode stack 10. In this case, the laminated battery 1 has two regions R between the ends of the electrode stack and the ends of the current collector terminal of the laminate film 40. In this embodiment, the laminate film 40 may have a bent portion 41 in one of the two regions R, or in both regions.

[0070] The material of the current collector terminal 20 is not particularly limited as long as it has a current collecting function, and for example, it may be the same metal material as that of the positive electrode current collector and the negative electrode current collector.

[0071] 〈Current Collection Section〉

[0072] The current collecting portion 30 electrically connects the end of the electrode stack to the end of the current collecting terminal. The current collecting portion 30 may be formed by bundling the portion of the positive electrode current collector of the electrode stack 10 on which other layers are not stacked, or by bundling the portion of the negative electrode current collector of the electrode stack 10 on which other layers are not stacked.

[0073] Laminated film

[0074] The laminate film 40 seals the electrode stack 10 together with the current collecting terminal 20. The laminate film may include a sealing resin layer, a metal layer, and a protective resin layer in this order along the thickness direction.

[0075] Examples of materials for the sealing resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective resin layer include polyethylene terephthalate (PET) and nylon.

[0076] The thickness of the sealing resin layer is, for example, 40 μm to 100 μm. The thickness of the metal layer is, for example, 30 μm to 60 μm. The thickness of the protective resin layer is, for example, 20 μm to 60 μm. The thickness of the laminate film is, for example, 80 μm to 250 μm.

Claims

1. A laminate battery comprising an electrode stack, a current collecting terminal disposed on a side surface of the electrode stack, a current collecting portion electrically connecting an end portion of the electrode stack to an end portion of the current collecting terminal, and a laminate film that seals the electrode stack together with the current collecting terminal, wherein: The laminate film has a bent portion in a region between an end portion of the electrode stack and an end portion of the current collector terminal.

2. The laminated battery according to claim 1, wherein The bent portion has a convex portion that bulges toward the inner side or the outer side of the laminate film.

3. The laminated battery according to claim 1, wherein The ratio of the height of the bent portion to the thickness of the thinner one of the electrode stack and the current collector terminal is 0.1 or more.

4. The laminate battery according to any one of claims 1 to 3, wherein A distance L from an end portion of the electrode stack to an end portion of the current collector terminal is not less than 1 mm and not more than 100 mm.

5. The laminate battery according to any one of claims 1 to 3, wherein A ratio L / T1 of a distance L from an end portion of the electrode stack to an end portion of the collector terminal to a thickness T1 of the electrode stack is greater than 0.01 and less than 100, and a ratio L / T2 of a distance L from an end portion of the electrode stack to an end portion of the collector terminal to a thickness T2 of the collector terminal is greater than 0.001 and less than 100.

Images