Laminate battery

Abstract

To provide a laminate battery capable of alleviating an influence of a change in pressure inside a laminate film and / or a change in volume of an electrode lamination body in accordance with charging and discharging of a battery.SOLUTION: A laminated battery 1 includes: an electrode lamination body 10; a current collecting terminal 20 disposed on a side surface part of the electrode lamination body 10; a current collecting part 30 that electrically connects an end part of the electrode lamination body and an end part of the current collecting terminal; and a laminate film 40 that seals the electrode lamination body 10 together with the current collecting terminal 20. The laminate film 40 in the laminated battery 1 has a bent part 41 in a region R between the end part of the electrode lamination body and the end part of the current collecting part terminal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a laminate battery. [Background technology]

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

[0003] In this regard, Patent Document 1 discloses a laminated battery that stably ruptures the exterior body (laminate film) to release the internal pressure when the internal pressure of the exterior body rises to a predetermined value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-145145 Summary of the Invention [Problem to be solved by the invention]

[0005] Even if the pressure inside the laminate film rises abnormally, it is desirable that the sealed portion of the laminate film not be torn as long as the pressure is within an allowable range.

[0006] In laminate batteries, depending on the type of electrode active material used, the volume of the electrode laminate may change as the battery is charged and discharged. Because the inside of the laminate film is sealed, such volume change of the electrode laminate may cause a change in the pressure inside the laminate film. That is, expansion of the electrode laminate may increase the pressure inside the laminate film, and contraction of the electrode laminate may decrease the pressure inside the laminate film.

[0007] The present inventors have found that an increase in pressure inside the laminate film due to expansion of the electrode laminate may cause the sealing portion of the laminate film to rupture, and that the expansion of the electrode laminate itself may cause damage to the laminate film.The present inventors have also found that a decrease in pressure inside the laminate film due to contraction of the electrode laminate may cause tensile stress in the laminate film, which may result in the sealing portion of the laminate film to rupture.

[0008] An object of the present disclosure is to provide a laminate battery that can mitigate the effects of changes in pressure inside the laminate film and / or changes in the volume of the electrode laminate that accompany charging and discharging of the battery. [Means for solving the problem]

[0009] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> an electrode stack; a current collecting terminal disposed on a side surface of the electrode stack; a current collecting portion electrically connecting an end of the electrode stack and an end of the current collecting terminal; and a laminate film that seals the electrode stack together with the current collecting terminals; A laminated battery having The laminated battery, wherein the laminated film has a bent portion in a region between an end of the electrode stack and an end of the current collecting terminal. <Aspect 2> 2. The laminate battery according to claim 1, wherein the bent portion has a convex portion that is convex toward the inside or outside of the laminate film. <Aspect 3> 3. The laminate battery according to claim 1, wherein the ratio of the height of the bent portion to the thickness of the thinner of the electrode laminate and the current collector terminal is 0.1 or more. <Aspect 4> 4. The laminate battery according to any one of aspects 1 to 3, wherein a distance L from an end of the electrode laminate to an end of the current collector terminal is 1 mm or more and 100 mm or less. <Aspect 5> A laminate battery according to any one of aspects 1 to 4, wherein a ratio L / T1 of a distance L from an end of the electrode laminate to an end of the current collector terminal to a thickness T1 of the electrode laminate is 0.01 or more and 100 or less, and a ratio L / T2 of a distance L from the end of the electrode laminate to a thickness T2 of the current collector terminal is 0.001 or more and 100 or less. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a laminate battery that can mitigate the effects of changes in pressure inside the laminate film and / or changes in the volume of the electrode laminate that accompany charging and discharging of the battery. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic plan view showing an example of a laminate battery according to the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of a laminate battery of the present disclosure with an area R enlarged. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an example of a laminate battery of the present disclosure with an area R enlarged. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an example of a laminate battery of the present disclosure with region R enlarged. [Figure 5] FIG. 5 is a schematic cross-sectional view illustrating the function of the laminate battery of the present disclosure. [Figure 6] FIG. 6 is a schematic cross-sectional view corresponding to FIG. 5 of a laminate battery according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure. Furthermore, the dimensional relationships in the drawings do not reflect the actual dimensional relationships.

[0013] Laminated battery As illustrated in Fig. 1, a laminate battery 1 (also called a pouch battery) of the present disclosure has an electrode laminate 10, a current collecting terminal 20 disposed on a side surface of the electrode laminate 10, a current collecting portion 30 electrically connecting an end of the electrode laminate to an end of the current collecting terminal, and a laminate film 40 sealing the electrode laminate 10 together with the current collecting terminal 20. Furthermore, as illustrated in Figs. 2 to 4, the laminate film 40 in the laminate battery 1 of the present disclosure has a bent portion 41 in a region R between the end of the electrode laminate and the end of the current collecting terminal.

[0014] The present inventors believe that one of the reasons why a laminate battery cannot mitigate the effects of pressure changes inside the laminate film and / or volume changes of the electrode laminate accompanying charge and discharge of the battery is that the laminate film does not have excess length in the region between the end of the electrode laminate and the end of the current collector terminal, i.e., the region that is not in contact with either the electrode laminate or the current collector terminal, as illustrated in Figure 6(a). In this case, as illustrated in Figure 6(b), for example, if the pressure inside the laminate film increases, the sealed portion of the laminate film (the sealed portion between the laminate film and the current collector terminal in Figure 6(b)) may rupture.

[0015] In this regard, the present inventors have discovered that forming a bent portion 41 in a region R between the end of the electrode stack and the end of the current collecting terminal in a laminate film 40 can mitigate the effects of pressure changes within the laminate film and / or volume changes in the electrode stack associated with battery charging and discharging. The reason for this is believed to be that, as illustrated in FIG. 5(a), the laminate film 40 has excess length in region R, resulting in the presence of a bent portion 41. Therefore, even if an increase in pressure occurs within the laminate film, the laminate film 40 deforms so that the space formed by the bent portion 41 collapses, as illustrated in FIG. 5(b), increasing the volume of the space within the laminate film. This is believed to mitigate the effects of pressure changes within the laminate film and / or volume changes in the electrode stack associated with battery charging and discharging.

[0016] In the present disclosure, damage to the laminate film may include, for example, damage caused by the electrode laminate expanding, which increases the pressure applied to the laminate film by the electrode laminate at the edges and corners where the electrode laminate and the laminate film are in contact.

[0017] The laminate battery 1 of the present disclosure includes an electrode laminate 10, a current collecting terminal 20 disposed on a side surface of the electrode laminate 10, a current collecting portion 30 electrically connecting an end of the electrode laminate to an end of the current collecting terminal, and a laminate film 40 sealing the electrode laminate 10 together with the current collecting terminal 20. In the present disclosure, the end of the electrode laminate refers to the end of the electrode laminate that faces the current collecting terminal. The end of the current collecting terminal refers to the end of the current collecting terminal that faces the electrode laminate.

[0018] The laminate film 40 in the laminate battery 1 of the present disclosure has a bent portion 41 in a region R between the end of the electrode laminate and the end of the current collector terminal.

[0019] The shape of the bent portion 41 is not particularly limited. As illustrated in Figures 2 and 3, the bent portion 41 may have a convex portion that is convex toward the inside of the laminate film 40. This configuration can prevent the laminate battery 1 of the present disclosure from increasing in thickness, and therefore, when multiple laminate batteries 1 are stacked and restrained to form a battery module, the bent portion 41 can prevent the laminate battery 1 from interfering with pressure equalization.

[0020] 2 is a schematic cross-sectional view showing an example of the shape of the bent portion 41 when the thickness of the electrode laminate 10 is the same as that of the current collector terminal 20. FIG. 3 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 smaller than that of the electrode laminate 10.

[0021] There are no particular limitations on the method for forming the bent portion 41 having a convex portion that is convex toward the inside of the laminate film 40. Examples include a method in which the laminate film 40 is processed to have a bent shape in advance, and a method in which when sealing the electrode stack 10 with the laminate film 40, the laminate film 40 is bent while sealing under reduced pressure.

[0022] 4, the bent portion 41 may have a convex portion that is convex toward the outside of the laminate film 40. This configuration particularly makes it easier to mitigate the effects of a decrease in pressure inside the laminate film and / or shrinkage of the electrode laminate due to discharge of the battery.

[0023] There are no particular limitations on the method for forming the bent portion 41 having a convex portion that is convex toward the outside of the laminate film 40. Examples include a method in which the laminate film 40 is pre-processed to have a bent shape, and a method in which the electrode stack 10 is sealed with the laminate film 40 and the current collecting terminal 20, and then the current collecting terminal 20 is pressed toward the electrode stack 10 to bend it.

[0024] When the bent portion 41 has a convex portion that is convex 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 from the end of the electrode laminate to the end of the current collecting terminal. With this configuration, even if there is a change in pressure inside the laminate film and / or a change in the volume of the electrode laminate due to charging and discharging of the battery, interference between the electrode laminate and the current collecting terminal and the laminate film can be easily prevented.

[0025] The laminate film 40 may have a bent portion 41 on either the upper side or the lower side in the thickness direction of the electrode laminate 10, or may have bent portions 41 on both the upper side and the lower side in the thickness direction of the electrode laminate 10. The upper bent portion may be referred to as 41a, and the lower bent portion may be referred to as 41b.

[0026] The ratio of the height H (mm) of the bent portion to the thickness (mm) of either the electrode laminate 10 or the current collecting terminal 20, whichever is thinner, may be 0.1 or more. For example, when the thickness T2 of the current collecting terminal is thinner than the thickness T1 of the electrode laminate, the ratio is expressed as H / T2. This ratio may be 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, or 0.7 or more, and may be 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. A high ratio can effectively mitigate the effects of changes in pressure inside the laminate film and / or volumetric changes of the electrode laminate associated with battery charging and discharging, even if these changes are significant. A low ratio can more easily form the bent portion 41 without excessive concern about damage to the current collecting portion 30 due to contact between the laminate film and the current collecting portion.

[0027] The height H of the bent portion means the shortest distance from an imaginary straight line connecting the lower side forming the end of the electrode laminate and the lower side forming the end of the current collecting terminal in the laminate film to the apex 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 forming the end of the electrode laminate and the upper side forming the end of the current collecting terminal in the laminate film to the apex of the convex portion of the upper bent portion 41a in the laminate film.

[0028] When the electrode laminate 10 has bent portions 41a and 41b on both the upper and lower sides in the thickness direction and the thickness T1 of the electrode laminate is equal to the thickness T2 of the current collecting terminal, the height of the bent portion 41a may be equal to the height of the bent portion 41b, as illustrated in FIG. 2.

[0029] The electrode laminate 10 has bent portions 41a and 41b on both the upper and lower sides in the thickness direction, and when the positions of the electrode laminate and the current collector terminal are in the relationship illustrated in Fig. 3 and the thickness T1 of the electrode laminate is greater than the thickness T2 of the current collector terminal, the height of the bent portion 41a may be less than the height of the bent portion 41b. To achieve this configuration, the bent portion 41b can be formed on the electrode laminate 10 side, and the bent portion 41a can be formed on the current collector terminal 20 side.

[0030] The distance L from the end of the electrode laminate to the end of the current collecting terminal may be 1 mm or more and 100 mm or less. This distance L may be 2 mm or more, 5 mm or more, or 10 mm or more, and may be 50 mm or less, 25 mm or less, or 10 mm or less. When this distance L is within the above range, bent portion 41 is easily formed, and as a result, the effect of the present disclosure of mitigating the effects of changes in pressure inside the laminate film and / or changes in volume of the electrode laminate due to charging and discharging of the battery is easily achieved.

[0031] The ratio L / T1 of the distance L from the end of the electrode laminate to the end of the current collecting terminal to the thickness T1 of the electrode laminate may be 0.01 or more and 100 or less, and the ratio L / T2 of the distance L from the end of the electrode laminate to the thickness T2 of the current collecting terminal may be 0.001 or more and 100 or less. The ratio L / T1 may be 0.1 or more, 0.5 or more, or 1 or more, and may be 50 or less, 25 or less, 10 or less, 5 or less, or 1 or less. The ratio L / T2 may be 0.01 or more, 0.05 or more, or 0.1 or more, and may be 10 or less, 5 or less, 1 or less, 0.5 or less, or 0.1 or less. When these ratios are within the above ranges, the bent portion 41 is easily formed, and as a result, the effect of the present disclosure of mitigating the effects of changes in pressure inside the laminate film and / or changes in volume of the electrode laminate due to charging and discharging of the battery is easily achieved.

[0032] 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.

[0033] The ratio T2 / T1 of the thickness T2 of the current collecting terminal to the thickness T1 of the electrode laminate may be 0.1 or more, 0.3 or more, 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more, and may be 1 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.5 or less.

[0034] Although the laminate battery of the present disclosure has been described above in terms of an embodiment in which the laminate film has a bent portion in the stacking direction of the electrode stack, the position at which the bent portion is formed is not particularly limited. For example, the laminate film may have a bent portion in the surface direction of the electrode stack.

[0035] The elements constituting the laminate battery of the present disclosure will be described below.

[0036] <Electrode laminate> The electrode laminate 10 functions as a power generating element of the laminate battery 1. The shape of the electrode laminate 10 is not particularly limited, and may have, for example, a top surface, a bottom surface opposite the top surface, and four side surfaces connecting the top surface and the bottom surface. The shape of the top surface is not particularly limited, and examples thereof include quadrilaterals such as a square, rectangle, rhombus, trapezoid, and parallelogram. The shape of the top surface may also be a polygon other than a quadrilateral, or may be a curved shape such as a circle. The shape of the bottom surface is the same as that of the top surface. The shape of the side surfaces is not particularly limited, and examples thereof include quadrilaterals such as a square, rectangle, rhombus, trapezoid, and parallelogram.

[0037] The electrode stack 10 may have, in this order, 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.

[0038] <Collector terminal> The current collecting terminal 20 is disposed on a side surface of the electrode laminate 10. The current collecting terminal 20 may be disposed on a pair of opposing side surfaces of the electrode laminate 10. In this case, the laminate battery 1 has two regions R between the end of the electrode laminate of the laminate film 40 and the end of the current collecting terminal. In this embodiment, the laminate film 40 may have a bent portion 41 in one of the two regions R, or may have bent portions 41 in both of them.

[0039] The material of the current collector terminal 20 is not particularly limited as long as it has a current collecting function, and may be, for example, the same metal material as that of the positive electrode current collector and the negative electrode current collector.

[0040] <Current collecting section> The current collecting part 30 electrically connects an end of the electrode laminate to an end of the current collecting terminal. The current collecting part 30 may be a bundle of positive electrode current collectors in the electrode laminate 10 that are not laminated with other layers, or a bundle of negative electrode current collectors in the electrode laminate 10 that are not laminated with other layers.

[0041] <Laminating film> The laminate film 40 seals the electrode stack 10 together with the current collecting terminal 20. The laminate film may have a sealant resin layer, a metal layer, and a protective resin layer in this order along the thickness direction.

[0042] Examples of materials for the sealant resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective resin layer include polyethylene terephthalate (PET) and nylon.

[0043] The thickness of the sealant resin 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 protective 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. [Explanation of symbols]

[0044] 1 Laminated battery 10 Electrode laminate 20 Current collector terminal 30 Current collector 40 Laminating Film 41 Bend

Claims

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

2. The laminate battery according to claim 1 , wherein the bent portion has a convex portion that is convex toward the inside or outside of the laminate film.

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

4. 4. The laminate battery according to claim 1, wherein a distance L from an end of the electrode laminate to an end of the current collector terminal is 1 mm or more and 100 mm or less.

5. 4. The laminate battery according to claim 1, wherein a ratio L / T1 of a distance L from an end of the electrode laminate to an end of the current collector terminal to a thickness T1 of the electrode laminate is 0.01 or more and 100 or less, and a ratio L / T2 of a distance L from an end of the electrode laminate to a thickness T2 of the current collector terminal is 0.001 or more and 100 or less.

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