Laminated battery and battery stack

Abstract

To provide a laminated battery excellent in structural reliability of a laminate sheet even if it is exposed to a high temperature environment.SOLUTION: The laminate type battery of the present disclosure is a laminate type battery. The laminated battery includes an electrode body, a side member, a laminate sheet, and a tab film disposed between the side member and the laminate sheet. The side surface member and the laminate sheet are welded via the tab film. The tab film has an inner excess resin portion protruding from an end of the side member on the electrode body side. The side surface member includes an opposedly facing surface which opposedly faces the side surface of the electrode assembly. An angle formed by the facing surface of the side surface member and a direction in which the laminate sheet extends from a specific portion of the laminate sheet toward the electrode assembly is 100 degrees or more and 150 degrees or less. The specific portion indicates a portion of the laminate sheet that intersects with a virtual surface including the facing surface of the side member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to laminated batteries and battery stacks. [Background technology]

[0002] Laminated batteries are known as thin and lightweight batteries. In laminated batteries, an electrode assembly is housed in an exterior body made of a laminate sheet (hereinafter also referred to as a "laminated exterior body").

[0003] Patent Document 1 discloses a laminated battery. As shown in FIG. 15, the laminated battery 900 disclosed in Patent Document 1 includes an electrode assembly 910, a laminated exterior body 920, and a tab film 930. The electrode assembly 910 has an electrode body portion 911, a flat terminal portion 912, and a tab lead portion 913 that electrically connects the electrode body portion 911 and the terminal portion 912. The tab lead portion 913 is attached to a main surface S912 of the terminal portion 912. The laminated exterior body 920 has a bag-shaped portion 921 that houses the electrode body portion 911 and an edge portion 922 that sandwiches and seals the terminal portion 912. The tab film 930 is made of a thermoplastic resin. The tab film 930 is sandwiched between the terminal portion 912 and the edge portion 922, and has a welding portion 931 that welds the terminal portion 912 to the edge portion 922. The tab film 930 does not protrude from the inner end E912 of the terminal portion 912 toward the electrode body portion 911. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-194949 Summary of the Invention [Problem to be solved by the invention]

[0005] The welded portion 931 normally has an excess resin portion 932 on the electrode body portion 911 side of the welded portion 931 of the tab film 930. The excess resin portion 932 is formed by extruding the molten material of the tab film 930 toward the electrode body portion 911 when the welded portion 931 is formed by thermocompression bonding. The thickness L932 of the excess resin portion 932 (see FIG. 15) is thicker than the thickness T931 of the welded portion 931 (see FIG. 15).

[0006] The laminated battery 900 may be exposed to a high-temperature environment (e.g., approximately 90°C) during use. The excess resin portion 932 is formed on the main surface S912 of the terminal portion 912, which is harder than the laminated exterior body 920. Therefore, when the laminated battery is exposed to a high-temperature environment, the excess resin portion 932 may easily expand in the direction of the arrow in FIG. 15. In addition, the thermal expansion coefficient of the excess resin portion 932 is higher than that of the laminated exterior body 920. Therefore, when the laminated battery is exposed to a high-temperature environment, the volume change of the excess resin portion 932 is larger than the volume change of the laminated exterior body 920. In other words, the laminated exterior body 920 may be subjected to stress due to the volume expansion of the excess resin portion 932. As a result, the laminated exterior body 920 (i.e., the laminate sheet) may be damaged (e.g., torn, bulged, etc.). Therefore, there is a demand for a laminated battery in which the laminate sheet is less likely to break even when exposed to a high-temperature environment (in other words, the laminate sheet has excellent structural reliability).

[0007] The present disclosure has been made in consideration of the above circumstances. An object of one embodiment of the present disclosure is to provide a laminated battery and a battery stack in which the structural reliability of the laminate sheet is excellent even when exposed to a high-temperature environment. [Means for solving the problem]

[0008] The means for solving the above problems include the following embodiments.

[0009] <1> A laminated battery according to a first aspect of the present disclosure is a laminated battery comprising an electrode body, a side member arranged on a side of the electrode body, a laminate sheet covering the electrode body, and a tab film arranged between the side member and the laminate sheet, wherein the side member and the laminate sheet are welded together via the tab film, and the tab film has an inner excess resin portion protruding from the end of the side member on the electrode body side.

[0010] In the first embodiment, the tab film has an inner excess resin portion that protrudes from the end of the side member on the electrode body side. In other words, the laminated battery has a space on the side of the inner excess resin portion opposite the laminate sheet side in the thickness direction of the tab film. This makes the inner excess resin portion more likely to expand in volume on the side opposite the laminate sheet side when the laminated battery is exposed to high temperatures. In other words, the stress that the laminate sheet receives due to the volume expansion of the inner excess resin portion is less severe than in the past. As a result, the laminated battery of the first embodiment has excellent structural reliability of the laminate sheet even when exposed to high-temperature environments.

[0011] <2> In a laminated battery according to a first aspect of the present disclosure, the side surface member has an opposing surface that faces the side surface of the electrode assembly, and in a cross section of the laminated battery taken along a direction perpendicular to the side surface of the electrode assembly, the angle formed between the opposing surface of the side surface member and a direction in which the laminate sheet extends from a specific portion of the laminate sheet toward the electrode assembly is 90 degrees or more, and the specific portion indicates a portion of the laminate sheet that intersects with an imaginary plane that includes the opposing surface of the side surface member. <1> 1. The laminated battery according to claim 1.

[0012] In a second aspect, the angle formed between the opposing surface of the side surface member and the direction in which the laminate sheet extends from a specific portion of the laminate sheet toward the electrode body is 90 degrees or more. As a result, the surface area of ​​the portion of the inner excess resin portion that is not in contact with at least one of the side surface member and the laminate sheet is larger than when the angle is less than 90 degrees. Therefore, when the laminated battery is exposed to high temperatures, the inner excess resin portion is more likely to expand in volume on the side opposite the laminate sheet side of the inner excess resin portion. In other words, the stress that the laminate sheet experiences due to the volumetric expansion of the inner excess resin portion is further alleviated. As a result, the laminated battery of the second aspect has superior structural reliability of the laminate sheet even when exposed to high-temperature environments.

[0013] <3> A laminated battery according to a third aspect of the present disclosure is a battery in which the laminate sheet has a metal layer and a resin layer laminated on a surface of the metal layer facing the electrode body, the side surface member has an opposing surface facing the side surface of the electrode body, the inner excess resin portion has a covering portion covering an end of the opposing surface of the side surface member, and in a cross section of the laminated battery cut along a direction perpendicular to the side surface of the electrode body, the length of the covering portion from the end of the side surface member facing the electrode body in a direction parallel to the opposing surface is ½ or more times the thickness of the resin layer. <1> or <2> 1. The laminated battery according to claim 1.

[0014] In a third aspect, the length of the covering portion from the end of the side surface member on the electrode body side in a direction parallel to the opposing surface is at least half the thickness of the resin layer. This makes it less likely that the opposing surface of the side surface member and the laminate sheet will come into physical contact with each other due to the presence of the covering portion of the inner excess resin portion, compared to when the length of the covering portion is less than half the thickness of the resin layer. In other words, the occurrence of a short circuit is more reliably prevented. Furthermore, the covering portion of the inner excess resin portion is less likely to peel off from the terminal. As a result, the safety and structural reliability of the laminated battery of the third aspect are superior.

[0015] <4> A laminated battery according to a fourth aspect of the present disclosure is a battery in which the laminate sheet has a metal layer and a resin layer laminated on a surface of the metal layer facing the electrode body, the side surface member has an opposing surface facing the side surface of the electrode body, the inner excess resin portion has a covering portion covering an end of the opposing surface, and in a cross section of the laminated battery cut along a direction perpendicular to the side surface of the electrode body, the length of the covering portion from the end of the side surface member facing the electrode body in a direction parallel to the opposing surface is 1 / 5 or more of the length from the end of the side surface member facing the electrode body to the metal layer in a direction parallel to the opposing surface of the side surface. <1> ~ <3> The laminated battery according to any one of the above items.

[0016] In a fourth aspect, the length of the covering portion from the end of the side surface member on the electrode body side in a direction parallel to the opposing surface is at least 1 / 5 of the length from the end of the side surface member on the electrode body side in a direction parallel to the opposing surface to the metal layer (hereinafter also referred to as the "first length"). This makes it less likely that the opposing surface of the side surface member and the laminate sheet will come into physical contact with each other due to the presence of the covering portion of the inner excess resin portion, compared to when the length of the covering portion is less than 1 / 5 of the first length. In other words, the occurrence of a short circuit is more reliably prevented. Furthermore, the covering portion of the inner excess resin portion is less likely to peel off from the terminal. As a result, the safety and structural reliability of the laminated battery of the fourth aspect are superior.

[0017] <5> In a fifth aspect of the present disclosure, there is provided a laminated battery, wherein the end of the side member on the electrode body side is chamfered. <1> ~ <4> The laminated battery according to any one of the above items.

[0018] In the fifth aspect, the end of the end portion on the electrode body side is chamfered. As a result, the surface area of ​​the portion of the inner excess resin portion that is not in contact with at least one of the side member and the laminate sheet is larger than when the end portion on the electrode body side is not chamfered. As a result, when the laminated battery is exposed to high temperatures, the inner excess resin portion is more likely to expand in volume on the side opposite the laminate sheet side of the inner excess resin portion. In other words, the stress that the laminate sheet experiences due to the volume expansion of the inner excess resin portion is further alleviated. As a result, the laminated battery of the fifth aspect has superior structural reliability of the laminate sheet even when exposed to high-temperature environments.

[0019] <6> In a sixth aspect of the present disclosure, there is provided a laminated battery, wherein the tab film further has an outer excess resin portion protruding from an end of the side member opposite to the electrode body side. <1> ~ <5> The laminated battery according to any one of the above items.

[0020] In a sixth aspect, the tab film further includes the outer excess resin portion. Thus, when laminated batteries are stacked, the presence of the outer excess resin portion makes it difficult for one side surface member of an adjacent laminated battery to physically come into contact with the other side surface member or laminate sheet of the adjacent laminated battery. In other words, the occurrence of a short circuit is more reliably prevented than when the tab film does not include the outer excess resin portion. As a result, the safety and structural reliability of the laminated battery of the sixth aspect are superior.

[0021] <7> In a seventh aspect of the present disclosure, there is provided a laminated battery, wherein the inner excess resin portion protrudes from the entire periphery of the end of the side member on the electrode body side. <1> ~ <6> The laminated battery according to any one of the above items.

[0022] In a seventh aspect, the inner excess resin portion protrudes from the entire circumference of the end of the side surface member on the electrode body side. This makes the inner excess resin portion more likely to expand in volume on the side opposite the laminate sheet when the laminated battery is exposed to high temperatures than when the inner excess resin portion does not protrude from the entire circumference of the end of the side surface member on the electrode body side. In other words, the stress that the laminate sheet experiences due to the volumetric expansion of the inner excess resin portion is more mitigated. As a result, the laminated battery of the seventh aspect has superior structural reliability of the laminate sheet, even when exposed to high-temperature environments.

[0023] <8> In a laminated battery according to an eighth aspect of the present disclosure, the electrode body includes at least one unit electrode body, and the unit electrode body is formed by stacking a positive electrode current collector, a positive electrode layer, an electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order. <1> ~ <7> The laminated battery according to any one of the above items.

[0024] In the eighth aspect, the unit electrode body is formed by laminating a positive electrode current collector, a positive electrode layer, an electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order, resulting in a laminated battery of the eighth aspect having a higher energy density.

[0025] <9> A ninth aspect of the present disclosure provides a laminated battery, wherein the side surface member is a terminal, the terminal has an opposing surface facing the side surface of the electrode body, and the opposing surface is electrically connected to the electrode body. <1> ~ <8> The laminated battery according to any one of the above items.

[0026] Conventionally, flat terminals have been used as terminals. In flat terminals, the side surface of the terminal facing the main surface is the surface facing the electrode body of the terminal. The area of ​​the side surface of the terminal is small. Therefore, the electrode body is electrically connected to the main surface of the terminal. In a ninth aspect, the terminal has an opposing surface that faces the side surface of the electrode body, and the opposing surface is electrically connected to the electrode body. As a result, it is not necessary to ensure a sufficient length in the direction perpendicular to the opposing surface of the terminal (in other words, the length of the main surface in the direction perpendicular to the opposing surface of a conventional flat terminal) to electrically connect the terminal and the electrode body. In other words, in the ninth aspect, the length in the direction perpendicular to the opposing surface of the terminal can be made shorter than conventional. As a result, the structural efficiency of the laminated battery of the ninth aspect is superior.

[0027] <10> A laminated battery according to a tenth aspect of the present disclosure includes a pair of the terminals facing each other via the electrode body, <9> 1. The laminated battery according to claim 1.

[0028] <11> The battery stack of an eleventh aspect of the present disclosure includes a plurality of the electrode bodies stacked in a direction parallel to the side surfaces of the electrode bodies. <10> and a plurality of inter-battery connection terminals electrically connected to the terminals and connecting a plurality of the laminated batteries in series.

[0029] <12> A battery stack according to a twelfth aspect of the present disclosure includes the plurality of laminated batteries including a first battery and a second battery adjacent to the first battery, the plurality of inter-battery connection terminals including a first inter-battery connection terminal electrically connecting the first battery and the second battery, the first inter-battery connection terminal having a first terminal component electrically connected to one of the pair of terminals included in the first battery and a second terminal component electrically connected to one of the pair of terminals included in the second battery, and the first terminal component and the second terminal component are electrically connected. <11> 2. The battery stack according to claim 1, wherein the

[0030] In the twelfth aspect, the first inter-battery connection terminal has a first terminal component and a second terminal component, and the first terminal component and the second terminal component are electrically connected to each other. This makes the productivity of the battery stack of the twelfth aspect superior to that of a first inter-battery connection terminal not having the first terminal component and the second terminal component.

[0031] <13> A thirteenth aspect of the present disclosure relates to a method for manufacturing a laminated battery comprising an electrode body, a side member arranged on a side of the electrode body, a laminate sheet covering the electrode body, and a tab film arranged between the side member and the laminate sheet, and includes a step of welding the side member and the laminate sheet together with a heat bar via the tab film to form an inner excess resin portion protruding from the end of the side member on the electrode body side.

[0032] According to the method for producing a laminated battery of the thirteenth aspect, a laminated battery can be obtained in which the structural reliability of the laminate sheet is excellent even when exposed to a high-temperature environment.

[0033] <14> A fourteenth aspect of the present disclosure provides a method for manufacturing a laminated battery, wherein the heat bar has a flat portion that faces the side member via the laminate sheet and a tab film when the side member and the laminate sheet are welded together, and an inclined portion that is continuous with the flat portion and is inclined toward the opposite side of the side member from the flat portion, and the inclined portion includes a portion that does not face the side member via the laminate sheet and the tab film when the side member and the laminate sheet are welded together. <13> This is a method for producing the laminated battery described in 1.

[0034] If the heat bar has the flat portion but not the inclined portion, the non-contact specific portion of the laminate sheet is likely to warp when welding the side member and the laminate sheet due to the difference between the linear thermal expansion coefficient of the tab film and the linear thermal expansion coefficient of the metal layer included in the laminate sheet. The "non-contact specific portion of the laminate sheet" refers to a portion of the laminate sheet that does not come into contact with the heat bar and is adjacent to the portion of the laminate sheet that comes into contact with the heat bar. If the non-contact specific portion of the laminate sheet warps, it becomes difficult to form an inner excess resin portion having a covering portion that covers the end of the opposing surface facing the electrode body of the side member. In a fourteenth aspect, the heat bar has the flat portion and the inclined portion, and the inclined portion includes a portion that does not face the side member via the laminate sheet and tab film when the side member and the laminate sheet are welded together. This prevents warping of the non-contact specific portion of the laminate sheet when the side member and the laminate sheet are welded together by the inclined portion of the heat bar. This facilitates the formation of an inner excess resin portion having a covering portion that covers the end of the opposing surface of the side member that faces the electrode body. As a result, the laminate battery manufacturing method of the fourteenth aspect of the present disclosure provides a laminate battery with superior safety and structural reliability. [Effects of the Invention]

[0035] According to the present disclosure, a laminated battery and a battery stack are provided in which the structural reliability of the laminate sheet is excellent even when exposed to a high-temperature environment. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a perspective view showing the appearance of a laminated battery according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of the laminated battery of FIG. 1 taken along line C2-C2. [Figure 3] 3 is a partially enlarged cross-sectional view of the laminated battery of FIG. 1 taken along line C2-C2. [Figure 4] 4 is a partially enlarged cross-sectional view of the laminated battery of FIG. 1 taken along the line C4-C4. [Figure 5] FIG. 5 is a schematic cross-sectional view showing an example of a unit electrode body according to the first embodiment of the present disclosure. [Figure 6] FIG. 6 is a graph showing the welding strength of the end portion versus the ratio (L4 / L5) of the thickness L5 of the resin layer to the length L4 of the covering portion. [Figure 7] FIG. 7 is a graph showing the welding strength of the end portion versus the ratio (L4 / L6) of the length L6 of the resin layer to the length L4 of the covering portion. [Figure 8] FIG. 8 is a perspective view showing the appearance of the battery stack according to the first embodiment of the present disclosure. [Figure 9A] FIG. 9A is a diagram for explaining a method for manufacturing a laminated battery according to the first embodiment of the present disclosure. [Figure 9B] FIG. 9B is a diagram for explaining the method for manufacturing the laminated battery according to the first embodiment of the present disclosure. [Figure 9C] FIG. 9C is a view for explaining the method for manufacturing the laminated battery according to the first embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram for explaining the method for manufacturing the laminated battery according to the first embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram for explaining the method for manufacturing the laminated battery according to the first embodiment of the present disclosure. [Figure 12] FIG. 12 is a cross-sectional view of a laminated battery according to a second embodiment of the present disclosure. [Figure 13] FIG. 13 is a cross-sectional view of a laminated battery according to a third embodiment of the present disclosure. [Figure 14] FIG. 14 is a perspective view showing the appearance of a battery stack according to a fourth embodiment of the present disclosure. [Figure 15] FIG. 15 is a cross-sectional view of a conventional laminated battery. DETAILED DESCRIPTION OF THE INVENTION

[0037] In the present disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0038] Hereinafter, embodiments of a laminated battery, a battery stack, and a method for manufacturing a laminated battery according to the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0039] (1) First embodiment As shown in FIG. 1, a laminated battery 1A according to a first embodiment of the present disclosure includes a tab film 10A, a pair of terminals 20A that are an example of side members, a laminate sheet 30, and an electrode assembly 40. One of the pair of terminals 20A is a positive electrode terminal. The other of the pair of terminals 20A is a negative electrode terminal. The electrode assembly 40 is a rectangular parallelepiped.

[0040] In the first embodiment, one side of the longitudinal direction of the main surface of the electrode body 40 is defined as the positive X-axis direction (hereinafter also referred to as the "front side"), and the opposite side is defined as the negative X-axis direction (hereinafter also referred to as the "rear side"). One side of the lateral direction of the main surface of the electrode body 40 is defined as the positive Y-axis direction (hereinafter also referred to as the "right side"), and the opposite side is defined as the negative Y-axis direction (hereinafter also referred to as the "left side"). One side of the thickness direction of the electrode body 40 is defined as the positive Z-axis direction (hereinafter also referred to as the "upper side"), and the opposite side is defined as the negative Z-axis direction (hereinafter also referred to as the "lower side"). The X-axis, Y-axis, and Z-axis are perpendicular to each other. Note that these directions do not limit the orientation of the laminated battery 1A of the present disclosure during use.

[0041] As shown in FIG. 2, the pair of terminals 20A are arranged opposite each other with the electrode body 40 interposed therebetween. Specifically, one of the pair of terminals 20A is arranged on the front surface SA40 of the electrode body 40. The other of the pair of terminals 20A is arranged on the rear surface SB40 of the electrode body 40. Each of the pair of terminals 20A is electrically connected to the electrode body 40. A laminate sheet 30 covers the electrode body 40. A tab film 10A is arranged between the terminal 20A and the laminate sheet 30. Each of the pair of terminals 20A and the laminate sheet 30 are welded via the tab film 10A. The electrode body 40 is sealed by the pair of terminals 20A and the laminate sheet 30.

[0042] In the first embodiment, the laminated battery 1A is a laminated lithium secondary battery using a solid electrolyte. Applications of the laminated battery 1A include, for example, a power source for an in-vehicle device, a power source for an information processing device (for example, a personal computer, a smartphone, etc.), a power source for storing electricity, etc.

[0043] (1.1) Terminal The terminal 20A is a rectangular parallelepiped object with its longitudinal direction in the left-right direction (Y-axis direction) and its lateral direction in the front-rear direction (X-axis direction).

[0044] One of the pair of terminals 20A has an opposing surface SA20 that faces the front surface SA40 of the electrode body 40. The other of the pair of terminals 20A has an opposing surface SA20 that faces the rear surface SB40 of the electrode body 40. The opposing surface SA20 of each of the pair of terminals 20A is electrically connected to the electrode body 40. The length L1 (see FIG. 2) of the opposing surface SA20 of each of the pair of terminals 20A in the up-down direction (Z-axis direction) is longer than that of conventional terminals. The length L1 is, for example, 0.1 cm or more. The length L2 (see FIG. 2) of each of the pair of terminals 20A in the front-to-back direction (X-axis direction) is shorter than that of conventional terminals. The length L2 is, for example, 2.0 cm or less. The terminal 20A may be made of a metal (for example, stainless steel (SUS)).

[0045] (1.2) Tab Film The tab film 10A has a function of electrically insulating the laminate sheet 30 from the terminal 20A, and a function of joining the laminate sheet 30 to the terminal 20A.

[0046] The tab film 10A is disposed over the entire surface of all side surfaces SB20 of the pair of terminals 20A facing the opposing surfaces SA20.

[0047] The tab film 10A is made of a first thermoplastic resin composition. The first thermoplastic resin composition includes a first thermoplastic resin. Examples of the first thermoplastic resin include olefin-based resins (e.g., polypropylene, polyethylene, etc.), polyvinyl chloride, polyvinylidene chloride, polystyrene-based resins, acrylonitrile-styrene copolymer (AS) resins, acrylonitrile-butadiene-styrene copolymer (ABS) resins, polyester-based resins, poly(meth)acrylic resins, polyvinyl alcohol, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyether-based resins, polyacetal-based resins, fluorine-based resins, polysulfone-based resins, polyphenylene sulfide resins, and polyketone-based resins. Among these, the first thermoplastic resin preferably includes acid-modified polypropylene to improve adhesion to the terminal 20A. The first thermoplastic resin composition may include a compounding agent, if necessary. Examples of the compounding agents include heat stabilizers, antioxidants, pigments, weathering agents, flame retardants, plasticizers, dispersants, lubricants, release agents, and antistatic agents.

[0048] The shape of the tab film 10A will be described in detail later with reference to FIGS.

[0049] (1.3) Laminate sheet The laminate sheet 30 covers the electrode body 40 and seals the electrode body 40 together with the pair of terminals 20A. One laminate sheet 30 is used. The single laminate sheet 30 is folded to function as a laminate exterior material.

[0050] The laminate sheet 30 has a metal layer 31 and a resin layer 32. The resin layer 32 is laminated on a surface SA31 of the metal layer 31 on the electrode body 40 side. The metal layer 31 blocks the passage of gas (for example, moisture, air, etc.) between the outside and the inside of the laminated battery 1 A. The material of the metal layer 31 is a metal (for example, aluminum, etc.). The resin layer 32 electrically insulates the pair of terminals 20A and the electrode assembly 40 from the metal layer 31. The resin layer 32 is made of a second thermoplastic resin composition. The second thermoplastic resin composition includes a second thermoplastic resin. The second thermoplastic resin is not particularly limited, and examples include those similar to those exemplified as the first thermoplastic resin. In particular, the second thermoplastic resin preferably includes a resin compatible with the first thermoplastic resin. This allows the tab film 10A and the resin layer 32 to be welded together. "Compatible" means that the first thermoplastic resin and the second thermoplastic resin are mixed without separating in an atmosphere in which they melt. The resin compatible with the first thermoplastic resin is appropriately selected depending on the type of first thermoplastic resin. When the first thermoplastic resin includes acid-modified polypropylene, the second thermoplastic resin preferably includes unmodified polypropylene. Acid-modified polypropylene has excellent metal adhesion, while unmodified polypropylene has poor metal adhesion. Therefore, when the first thermoplastic resin contains acid-modified polypropylene and the second thermoplastic resin contains unmodified polypropylene, the tab film 10A and the resin layer 32 are welded together, while welding between the resin layer 32 and the electrode body 40 is prevented. The second thermoplastic resin composition may contain additives as needed. The additives are the same as those exemplified as the additives for the first thermoplastic resin composition.

[0051] (1.4) Electrode body The electrode assembly 40 functions as a power generating element of the laminated battery 1A.

[0052] The electrode assembly 40 has a plurality of unit electrode bodies 41 and a pair of current collecting tabs 42. One of the pair of current collecting tabs 42 is a positive electrode current collecting tab and is electrically connected to a positive electrode terminal. The other of the pair of current collecting tabs 42 is a negative electrode current collecting tab and is electrically connected to a negative electrode terminal. Each of the pair of current collecting tabs 42 is electrically connected to a plurality of unit electrode bodies 41.

[0053] The plurality of unit electrode bodies 41 are rectangular parallelepiped objects. In the first embodiment, the length L3 (see FIG. 2) of the plurality of unit electrode bodies 41 in the vertical direction (Z-axis direction) is longer than the length L1 (see FIG. 2) of each opposing surface SA20 of the pair of terminals 20A in the vertical direction (Z-axis direction).

[0054] The battery structure of the electrode assembly 40 will be described in detail below with reference to FIG.

[0055] (1.5) Tab Film Shape As shown in Figures 3 and 4, the tab film 10A has an inner excess resin portion 11, a thermocompression-bonded portion 12, and a non-thermocompression-bonded portion 13. The inner excess resin portion 11 protrudes from the entire periphery of the end EA20 of the terminal 20A on the electrode body 40 side. The inner excess resin portion 11 is not sandwiched between the terminal 20A and the laminate sheet 30. The thermocompression-bonded portion 12 and the non-thermocompression-bonded portion 13 are sandwiched between the terminal 20A and the laminate sheet 30. The thermocompression-bonded portion 12 is located between the inner excess resin portion 11 and the non-thermocompression-bonded portion 13. The inner excess resin portion 11, the thermocompression-bonded portion 12, and the non-thermocompression-bonded portion 13 are integral.

[0056] (1.5.1) Excess resin inside The inner excess resin portion 11 protrudes from the end EA20 of the terminal 20A on the electrode body 40 side toward the electrode body 40. The inner excess resin portion 11 is formed, for example, by extruding a molten material of the tab film 10A from the end EA20 on the electrode body 40 side of the terminal 20A when the thermocompression-bonded portion 12 is formed by thermocompression bonding. The inner excess resin portion 11 may be welded to the laminate sheet 30 (specifically, the resin layer 32).

[0057] 3, in a cross section of laminate battery 1A taken along the front-rear direction (X-axis direction) perpendicular to the front surface SA40 of electrode assembly 40, a first angle θA is 90 degrees or greater. The first angle θA indicates the angle between the facing surface SA20 of terminal 20A and the direction DA30 in which laminate sheet 30 extends from a specific portion RA30 of laminate sheet 30 toward the electrode assembly 40 (e.g., the negative direction of the X-axis). The specific portion RA30 indicates the portion of laminate sheet 30 that intersects with an imaginary plane S that includes the facing surface SA20 of terminal 20A. The first angle θA is preferably 90 degrees to 150 degrees, and more preferably 100 degrees to 135 degrees.

[0058] 3, the inner excess resin portion 11 has a covering portion R11 that covers the end R20A of the opposing surface SA20 of the terminal 20A. In a cross section of the laminated battery 1A cut along the front-rear direction (X-axis direction) perpendicular to the front surface SA40 of the electrode body 40, the length L4 (see FIG. 3) of the covering portion R11 from the end EA20 on the electrode body 40 side in the up-down direction (Z-axis direction) parallel to the opposing surface SA20 of the terminal 20A is at least half the thickness L5 (see FIG. 2) of the resin layer 32. The length L4 of the covering portion R11 is preferably 1 / 2 or more times the thickness L5 of the resin layer 32, and more preferably 3 / 4 or more times.

[0059] As shown in Figure 3, in a cross section of the laminated battery 1A cut along the front-to-back direction (X-axis direction) perpendicular to the front surface SA40 of the electrode body 40, the length L4 (see Figure 3) of the covering portion R11 from the end EA20 on the electrode body 40 side in the front-to-back direction (X-axis direction) parallel to the opposing surface SA20 of the terminal 20A is at least 1 / 5 times the length L6 (see Figure 3) from the end EA20 on the electrode body 40 side to the metal layer 31 in the up-down direction (Z-axis direction) parallel to the opposing surface SA20 of the terminal 20A. The length L4 of the covering portion R11 is preferably 1 / 5 or more, more preferably 2 / 5 or more, of the length L6.

[0060] 4, in a cross section of laminate battery 1A taken along the left-right direction (Y-axis direction) perpendicular to the front surface SA40 of electrode assembly 40, second angle θB is 90 degrees or greater. The second angle θB indicates the angle between the facing surface SA20 of terminal 20A and the direction DB30 in which laminate sheet 30 extends from specific portion RA30 of laminate sheet 30 toward the electrode assembly 40 (e.g., the negative direction of the X-axis). Specific portion RA30 indicates the portion of laminate sheet 30 that intersects with imaginary plane S that includes facing surface SA20 of terminal 20A. The second angle θB is preferably 90 degrees to 150 degrees, and more preferably 100 degrees to 135 degrees.

[0061] As shown in Figure 4, in a cross section of the laminated battery 1A cut along the left-right direction (Y-axis direction) perpendicular to the front surface SA40 of the electrode body 40, the length L7 (see Figure 4) of the covering portion R11 from the end EA20 on the electrode body 40 side in the left-right direction (Y-axis direction) parallel to the opposing surface SA20 of the terminal 20A is at least half the thickness L5 (see Figure 2) of the resin layer 32. The length L7 of the covering portion R11 is preferably at least 1 / 2 times, and more preferably at least 3 / 4 times, the thickness L5 of the resin layer 32. The length L7 of the covering portion R11 may be the same as or different from the length L4 of the covering portion R11 (see FIG. 3).

[0062] As shown in Figure 4, in a cross section of the laminated battery 1A cut along the left-right direction (Y-axis direction) perpendicular to the front surface SA40 of the electrode body 40, the length L7 (see Figure 4) of the covering portion R11 from the end EA20 on the electrode body 40 side in the left-right direction (Y-axis direction) parallel to the opposing surface SA20 of the terminal 20A is at least 1 / 5 times the length L8 (see Figure 4) from the end EA20 on the electrode body 40 side to the metal layer 31 in the left-right direction (Y-axis direction) parallel to the opposing surface SA20 of the terminal 20A. The length L7 of the covering portion R11 is preferably 1 / 5 or more, more preferably 2 / 5 or more, of the length L8. The length L8 may be the same as or different from the length L6 (see FIG. 3).

[0063] (1.5.2) Thermocompression section The thermocompression-bonded portion 12 is a portion that is directly thermocompression-bonded via the laminate sheet 30 using a heating tool (for example, a heat bar). The thermocompression-bonded portion 12 is welded to the terminal 20A and the laminate sheet 30 (specifically, the resin layer 32). The length L9 (see FIGS. 3 and 4) of the thermocompression-bonded portion 12 in the front-rear direction (X-axis direction) is preferably 15 mm or less, and more preferably 3 mm to 10 mm. In the first embodiment, the position of the end of the thermocompression-bonded portion 12 in the negative X-axis direction is the same as the position of the end EA20 of the terminal 20A on the electrode body 40 side in the front-rear direction (X-axis direction).

[0064] (1.5.3) Non-thermocompression bonded part The non-thermocompression-bonded portion 13 is a portion that is not directly thermocompression-bonded via the laminate sheet 30 by a heating tool (e.g., a heat bar). The portion of the non-thermocompression-bonded portion 13 that is sandwiched between the terminal 20A and the laminate sheet 30 is welded to the terminal 20A and the laminate sheet 30 (specifically, the resin layer 32). The portion of the non-thermocompression-bonded portion 13 that is not sandwiched between the terminal 20A and the laminate sheet 30 is welded to the terminal 20A.

[0065] (1.6)Battery structure The unit electrode body 41 includes a so-called all-solid-state battery (the content of electrolytic solution as electrolyte is less than 5 mass % with respect to the total amount of electrolyte) that uses an inorganic solid electrolyte as the electrolyte. The structure of the electrode unit 41 may be a structure in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are stacked in this order along the vertical direction (Z-axis direction), for example, as shown in FIG. 5. The solid electrolyte layer B in FIG. 5 may have a two-layer structure. FIG. 5 is a schematic cross-sectional view showing an example of the electrode unit 41. The electrode unit 41 shown in FIG. 5 includes a negative electrode including a negative electrode current collector 410 and a negative electrode layer A, a solid electrolyte layer B, and a positive electrode including a positive electrode current collector 411 and a positive electrode layer C. The negative electrode layer A includes a negative electrode active material 412, a conductive additive 413, a binder 414, and a solid electrolyte 415. The positive electrode layer C includes a positive electrode active material 416, a conductive additive 417, a binder 418, and a solid electrolyte 419.

[0066] The plurality of unit electrode bodies 41 may be connected in series or in parallel.

[0067] The plurality of unit electrode bodies 41 may be configured by sealing the stacking end faces (side faces) of the stacking structure of the positive electrode layer / solid electrolyte layer / negative electrode layer with resin.

[0068] (1.6.1) Solid electrolyte layer The unit electrode body 41 includes a solid electrolyte layer. The solid electrolyte layer preferably includes one selected from the group consisting of a sulfide solid electrolyte, an oxide solid electrolyte, and a halide solid electrolyte.

[0069] The sulfide solid electrolyte preferably contains sulfur (S) as the main anion element, and further preferably contains, for example, Li and / or A. The A element is at least one selected from the group consisting of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In. The sulfide solid electrolyte may further contain at least one of O and a halogen element. Examples of the halogen element (X) include F, Cl, Br, and I. The composition of the sulfide solid electrolyte is not particularly limited, and examples include xLiS·(100-x)P2S5 (70≦x≦80), yLiI·zLiBr·(100-yz)(xLiS·(1-x)P2S5) (0.7≦x≦0.8, 0≦y≦30, 0≦z≦30). The sulfide solid electrolyte may have a composition represented by the following general formula (1): Formula (1): Li 4-x Ge 1-x P x S4(0 <x<1) In formula (1), at least a portion of the Ge may be substituted with at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. At least a portion of the P may be substituted with at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. At least a portion of the Li may be substituted with at least one selected from the group consisting of Na, K, Mg, Ca, and Zn. At least a portion of the S may be substituted with a halogen. The halogen is at least one of F, Cl, Br, and I.

[0070] The oxide solid electrolyte preferably contains oxygen (O) as the main anion element, and may contain, for example, Li, Q element (Q represents at least one of Nb, B, Al, Si, P, Ti, Zr, Mo, W, and S), and O. Examples of the oxide solid electrolyte include garnet-type solid electrolytes, perovskite-type solid electrolytes, Nasicon-type solid electrolytes, Li-PO-based solid electrolytes, and Li-BO-based solid electrolytes. Examples of the garnet-type solid electrolyte include Li7La3Zr2O 12 , Li 7-x La3(Zr 2-x Nb x )O 12 (0≦x≦2), Li5La3Nb2O 12 Examples of perovskite-type solid electrolytes include (Li,La)TiO3, (Li,La)NbO3, (Li,Sr)(Ta,Zr)O3, etc. Examples of Nasicon-type solid electrolytes include Li(Al,Ti)(PO4)3, Li(Al,Ga)(PO4)3, etc. Examples of Li-PO-based solid electrolytes include Li3PO4 and LIPON (a compound in which part of the O in Li3PO4 is substituted with N), and examples of Li-BO-based solid electrolytes include Li3BO3 and a compound in which part of the O in Li3BO3 is substituted with C, etc.

[0071] As the halide solid electrolyte, a solid electrolyte containing Li, M, and X (M represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br) is suitable. 6-3zY z X6 (where X represents Cl or Br, and 0 < z < 2), Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≤ 1.5) is preferred. Li 6-3z Y z Among X6, Li3YX6 (where X represents Cl or Br) is more preferred in terms of excellent lithium ion conductivity, and further Li3YCl6 is preferred. Also, Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≤ 1.5) is preferably included together with a solid electrolyte such as a sulfide solid electrolyte from the viewpoint of suppressing, for example, oxidative decomposition of the sulfide solid electrolyte.

[0072] The solid electrolyte layer may have a single-layer structure or a multi-layer structure of two or more layers.

[0073] The solid electrolyte layer may contain a binder or may not contain a binder. Examples of the binder that can be included in the solid electrolyte layer include, for example, vinyl halide resins, rubbers, polyolefin resins, etc. Examples of the vinyl halide resin include polyvinylidene fluoride (PVdF), a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP), etc. Examples of the polyolefin resin include butadiene rubber (BR), acrylate butadiene rubber (ABR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber (isobutylene-isoprene rubber), etc. Examples of the polyolefin resin include polyethylene, polypropylene, etc. The binder (C) may be a diene-based rubber containing a double bond in the main chain, for example, a butadiene-based rubber in which butadiene occupies 30 mol% or more of the whole.

[0074] (1.6.2) Positive electrode layer The unit electrode body 41 includes a positive electrode layer. The positive electrode layer contains a positive electrode active material. The positive electrode layer may contain at least one of a positive electrode solid electrolyte, a conductive additive, and a binder, as necessary.

[0075] The positive electrode active material preferably contains a lithium composite oxide. The lithium composite oxide may contain at least one element selected from the group consisting of F, Cl, N, S, Br, and I. The lithium composite oxide may have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immm, and P63-mmc (also referred to as P63mc or P6 / mmc). The lithium composite oxide may have an O2-type structure in which the transition metal, oxygen, and lithium are primarily arranged.

[0076] Examples of lithium composite oxides having a crystal structure belonging to R-3m include Li x Me y O α X β (Me represents at least one selected from the group consisting of Mn, Co, Ni, Fe, Al, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, W, B, Si, and P, and X represents at least one selected from the group consisting of F, Cl, N, S, Br, and I, and satisfy the conditions 0.5≦x≦1.5, 0.5≦y≦1.0, 1≦α<2, and 0<β≦1.)

[0077] Examples of lithium composite oxides having a crystal structure belonging to Immm include Li x1 M 1 A 1 2(1.5≦x1≦2.3, M 1 contains at least one selected from the group consisting of Ni, Co, Mn, Cu and Fe, and A 1 contains at least oxygen, and A 1 The ratio of oxygen in the oxide is 85 atomic % or more. x1 M 1A 1-x2 M 1B x2O 2-y A 2 y (0 ≦ x2 ≦ 0.5, 0 ≦ y ≦ 0.3, and at least one of x2 and y is not zero, and M 1A represents at least one selected from the group consisting of Ni, Co, Mn, Cu, and Fe, and M 1B represents at least one selected from the group consisting of Al, Mg, Sc, Ti, Cr, V, Zn, Ga, Zr, Mo, Nb, Ta, and W, and A2 represents at least one selected from the group consisting of F, Cl, Br, S, and P.) The composite oxide represented by this is mentioned.

[0078] As the lithium composite oxide having a crystal structure belonging to P63 - mmc, for example, M1 x M2 y O2 (M1 represents an alkali metal (at least one of Na and K is preferable), M2 represents a transition metal (at least one selected from the group consisting of Mn, Ni, Co, and Fe is preferable), and x + y satisfies 0 < x + y ≦ 2.) The composite oxide represented by this is mentioned.

[0079] As the lithium composite oxide having an O2 - type structure, for example, Li x [Li α (Mn a Co b M c ) 1-α O2 (0.5 < x < 1.1, 0.1 < α < 0.33, 0.17 < a < 0.93, 0.03 < b < 0.50, 0.04 < c < 0.33, and M represents at least one selected from the group consisting of Ni, Mg, Ti, Fe, Sn, Zr, Nb, Mo, W, and Bi.) The composite oxide represented by this is mentioned, and specific examples include Li 0.744 [Li 0.145 Mn 0.625 Co 0.115 Ni 0.115 O2 etc. are mentioned.

[0080] The positive electrode solid electrolyte preferably includes one selected from the group consisting of a sulfide solid electrolyte, an oxide solid electrolyte, and a halide solid electrolyte. Examples of the sulfide solid electrolyte include the same as those exemplified as the sulfide solid electrolyte contained in the solid electrolyte. Examples of the oxide solid electrolyte include the same as those exemplified as the oxide solid electrolyte contained in the solid electrolyte. Examples of the halide solid electrolyte include the same as those exemplified as the halide solid electrolyte contained in the solid electrolyte.

[0081] Examples of conductive additives include carbon materials, metal materials, and conductive polymer materials. Examples of carbon materials include carbon black (e.g., acetylene black, furnace black, ketjen black, etc.), fibrous carbon (e.g., vapor-grown carbon fiber, carbon nanotube, carbon nanofiber, etc.), graphite, and carbon fluoride. Examples of metallic materials include metal powder (e.g., aluminum powder, etc.), conductive whiskers (e.g., zinc oxide, potassium titanate, etc.), and conductive metal oxides (e.g., titanium oxide, etc.). Examples of conductive polymer materials include polyaniline, polypyrrole, and polythiophene. One type of conductive additive may be used alone, or two or more types may be mixed and used.

[0082] Examples of the binder include the same binders as those exemplified as the binder contained in the solid electrolyte layer.

[0083] (1.6.3) Positive electrode current collector The unit electrode body 41 includes a positive electrode current collector. The positive electrode current collector collects current from the positive electrode layer. The positive electrode current collector is disposed on the opposite side of the positive electrode layer from the solid electrolyte layer. The positive electrode current collector may be made of, for example, stainless steel, aluminum, copper, nickel, iron, titanium, or carbon, and is preferably an aluminum alloy foil or aluminum foil. The aluminum alloy foil or aluminum foil may be manufactured using powder. The positive electrode current collector may be, for example, in the form of a foil or a mesh. The positive electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface thereof.

[0084] (1.6.4) Negative electrode layer The unit electrode body 41 includes a negative electrode layer. The negative electrode layer contains a negative electrode active material. The negative electrode layer may contain at least one of a negative electrode solid electrolyte, a conductive additive, and a binder, as necessary. Examples of negative electrode active materials include Li-based active materials such as metallic lithium, carbon-based active materials such as graphite, oxide-based active materials such as lithium titanate, and Si-based active materials such as elemental Si. Examples of the conductive additive, negative electrode solid electrolyte, and binder used in the negative electrode layer include the same conductive additive, negative electrode solid electrolyte, and binder (C) as those exemplified in the positive electrode layer and the solid electrolyte and binder (C) contained in the solid electrolyte layer.

[0085] (1.6.5) Negative electrode current collector The unit electrode body 41 includes a negative electrode current collector. The negative electrode current collector collects current from the negative electrode layer. The negative electrode current collector is disposed on the opposite side of the negative electrode layer from the solid electrolyte layer. The negative electrode current collector may be made of, for example, stainless steel, aluminum, copper, nickel, iron, titanium, or carbon, with copper being preferred. The negative electrode current collector may be in the form of, for example, a foil or mesh. The negative electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface thereof.

[0086] (1.7) Action and Effect As described with reference to Figures 1 to 5, the laminated battery 1A includes an electrode assembly 40, a pair of terminals 20A, a laminate sheet 30, and a tab film 10A. The pair of terminals 20A and the laminate sheet 30 are welded via the tab film 10A. The tab film 10A has an inner excess resin portion 11 that protrudes from an end EA20 of the terminal 20A on the electrode assembly 40 side. The laminated battery 1A has a space on the side of the inner surplus resin portion 11 opposite the laminate sheet 30 in the thickness direction (Z-axis direction or Y-axis direction) of the tab film 10A. This makes it easier for the inner surplus resin portion 11 to expand in volume on the side opposite the laminate sheet 30 (i.e., the direction of the arrow in Figures 3 and 4) when the laminated battery 1A is exposed to high temperatures. In other words, the stress that the laminate sheet 30 receives due to the volume expansion of the inner surplus resin portion 11 is less severe than in the past. As a result, the laminated battery 1A has excellent structural reliability of the laminate sheet 30 even when exposed to high-temperature environments.

[0087] As described with reference to FIGS. 1 to 5, in the laminated battery 1A, the first angle θA and the second angle θB are each equal to or greater than 90 degrees. As a result, the surface area of ​​the portion of the inner surplus resin portion 11 that is not in contact with at least one of the terminal 20A and the laminate sheet 30 is larger than when the first angle θA and the second angle θB are each less than 90 degrees. This makes the inner surplus resin portion 11 more likely to expand in volume on the side opposite the laminate sheet 30 when the laminate battery 1A is exposed to high temperatures. This means that the stress on the laminate sheet 30 due to the volumetric expansion of the inner surplus resin portion 11 is more mitigated. As a result, the laminate battery 1A has superior structural reliability of the laminate sheet 30 even when exposed to high-temperature environments.

[0088] 1 to 5, in the laminated battery 1A, the length L4 (see FIG. 3) of the covering portion R11 from the end EA20 on the electrode assembly 40 side in the vertical direction (Z-axis direction) parallel to the opposing surface SA20 of the terminal 20A is at least half the thickness L5 (see FIG. 2) of the resin layer 32. The length L7 (see FIG. 4) of the covering portion R11 from the end EA20 on the electrode assembly 40 side is at least half the thickness L5 (see FIG. 2) of the resin layer 32. As a result, the covering portion R11 makes it difficult for the facing surface SA20 of the terminal 20A and the laminate sheet 30 to come into physical contact with each other. This means that short circuits are more reliably prevented. Furthermore, the covering portion of the inner excess resin portion is less likely to peel off from the terminal. As a result, the safety and structural reliability of the laminated battery 1A are improved.

[0089] Hereinafter, the relationship between the length L4 (see FIG. 3) of the covering portion R11 of the inner excess resin portion 11 and the thickness L5 (see FIG. 2) of the resin layer 32 of the laminate sheet 30 will be described with reference to FIG. 6 shows measurement data of the welding strength of the end portion (including end EA20) of terminal 20A versus the ratio (L4 / L5) when tab film 10A contains acid-modified polypropylene and resin layer 32 of laminate sheet 30 contains unmodified polypropylene. Length L4 (see FIG. 3) and length L7 (see FIG. 4) are the same. As shown in Fig. 6, the welding strength of the end portion depends on the ratio (L4 / L5). It was found that when the ratio (L4 / L5) is 0.5 or more, the welding strength of the end portion is significantly improved compared to when the ratio (L4 / L5) is less than 0.5. As a result, it was experimentally found that when the length L4 (see Fig. 3) of the covering portion R11 of the inner excess resin portion 11 is half or more the thickness L5 (see Fig. 2) of the resin layer 32, the covering portion R11 of the inner excess resin portion 11 is less likely to peel off from the terminal 20A.

[0090] The measurement method for the measurement data shown in Figure 6 was to measure the strength when the terminal was fixed and the laminate was pulled up in a direction perpendicular to the terminal seal surface.

[0091] 1 to 5, in the laminated battery 1A, the length L4 (see FIG. 3) of the covering portion R11 is at least 1 / 5 of the length L6 (see FIG. 3) from the end EA20 on the electrode assembly 40 side to the metal layer 31. The length L7 (see FIG. 4) of the covering portion R11 is at least 1 / 5 of the length L8 (see FIG. 4) from the end EA20 on the electrode assembly 40 side to the metal layer 31. As a result, the covering portion R11 makes it difficult for the facing surface SA20 of the terminal 20A and the laminate sheet 30 to come into physical contact with each other. In other words, the occurrence of a short circuit is more reliably prevented. Furthermore, the covering portion of the inner excess resin portion is less likely to peel off from the terminal. As a result, the safety and structural reliability of the laminated battery 1A are improved.

[0092] Hereinafter, with reference to FIG. 7, the relationship between the length L4 (see FIG. 3) of the covering portion R11 of the inner excess resin portion 11 and the length L6 (see FIG. 3) from the end EA20 on the electrode body 40 side to the metal layer 31 will be described. 7 shows measurement data of the welding strength of the end portion (including end EA20) of terminal 20A versus the ratio (L4 / L6) when tab film 10A contains acid-modified polypropylene and resin layer 32 of laminate sheet 30 contains unmodified polypropylene. Length L6 (see FIG. 3) and length L8 (see FIG. 4) are the same. As shown in Fig. 7, the welding strength of the end portion depends on the ratio (L4 / L6). It was found that when the ratio (L4 / L6) is 0.2 or more, the welding strength of the end portion is significantly improved compared to when the ratio (L4 / L6) is less than 0.2. As a result, it was experimentally found that when the length L4 (see Fig. 3) of the covering portion R11 of the inner excess resin portion 11 is 1 / 5 or more of the length L6 (see Fig. 3) from the end EA20 on the electrode body 40 side to the metal layer 31, the covering portion R11 of the inner excess resin portion 11 is less likely to peel off from the terminal 20A. The method for measuring the measurement data shown in FIG. 7 is the same as the method for measuring the measurement data shown in FIG.

[0093] As described with reference to FIGS. 1 to 5, in the laminated battery 1A, the inner excess resin portion 11 protrudes from the entire periphery of the end EA20 of the terminal 20A on the electrode body 40 side. As a result, when the laminated battery 1A is exposed to high temperatures, the inner surplus resin portion 11 is more likely to expand in volume on the side opposite the laminate sheet 30 than if the inner surplus resin portion 11 did not protrude from the entire circumference of the end EA20 of the terminal 20A on the electrode body 40 side. In other words, the stress that the laminate sheet receives due to the volume expansion of the inner surplus resin portion 11 is alleviated. As a result, the laminated battery 1A has superior structural reliability of the laminate sheet even when exposed to high-temperature environments.

[0094] 1 to 5, in the laminated battery 1A, the electrode assembly 40 includes a plurality of unit electrode bodies. Each unit electrode body is formed by laminating a positive electrode current collector, a positive electrode layer, an electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order. This allows the laminated battery 1A to have a higher energy density.

[0095] As described with reference to FIGS. 1 to 5, in the laminated battery 1A, the opposing surface SA20 of the terminal 20A is electrically connected to the electrode assembly 40. This eliminates the need to ensure a sufficient length L10 (see FIGS. 3 and 4) in the front-rear direction (X-axis direction) perpendicular to the opposing surface SA20 of the terminal 20A to electrically connect the terminal 20A and the electrode body 40. In other words, the length L10 in the front-rear direction (X-axis direction) of the terminal 20A can be made shorter than before. As a result, the structural efficiency of the laminated battery 1A is improved.

[0096] (2) Battery stack As shown in Fig. 8, the battery stack 2A according to the first embodiment of the present disclosure includes multiple laminated batteries 1A and multiple inter-battery connection terminals 50A. The multiple laminated batteries 1A are stacked in a vertical direction (Z-axis direction) parallel to the front surface SA40 of the electrode assembly 40. The multiple inter-battery connection terminals 50A are electrically connected to terminals 20A, connecting the multiple laminated batteries 1A in series.

[0097] The inter-battery connection terminal 50A is a component (bus bar) for electrically connecting the multiple laminated batteries 1A in series. The inter-battery connection terminal 50A is a single plate-like member. The terminal 20A of the laminated battery 1A has an outer surface SC20 on the opposite side of the facing surface SA20 in the front-to-rear direction (X-axis direction). The inter-battery connection terminal 50A is attached to the outer surface SC20 of the terminal 20A. The method for attaching the inter-battery connection terminal 50A is not particularly limited, and examples include methods using fastening parts and welding. Fastening parts include bolts, nuts, screws, rivets, or pins. Welding includes metal welding and brazing. The material of the inter-battery connection terminal 50A is metal (for example, stainless steel).

[0098] (3) Manufacturing method of laminated battery The method for manufacturing a laminated battery according to the first embodiment of the present disclosure is a method for manufacturing a laminated battery 1A. The method for manufacturing a laminated battery according to the first embodiment includes a preparation step, a covering step, a fixing step, and a welding step. The preparation step, covering step, fixing step, and welding step are performed in this order.

[0099] (3.1) Preparation process In the preparation step, a structure 60 and one laminate sheet 30 are prepared. The structure 60 includes an electrode assembly 40 and a pair of terminals 20A electrically connected to the electrode assembly 40. The method for preparing each of the structure 60 and the laminate sheet 30 may be a known method.

[0100] (3.2) Coating process 9A, in the covering step, the laminate sheet 30 is folded to cover the electrode assembly 40 included in the structure 60 with one laminate sheet 30. The method for covering the electrode assembly 40 with the laminate sheet 30 is not particularly limited, and may be, for example, a method in which a fold F30 that matches the shape of the electrode assembly 40 is formed in the laminate sheet 30 by a known method, and the laminate sheet 30 is folded along the fold F30.

[0101] (3.3) Fixing process 9B, in the fixing step, a region RA60 where the ends of the folded laminate sheet 30 overlap is thermocompression-bonded to fix the shape of the laminate sheet 30 in a state where it covers the electrode body 40. The method for thermocompression-bonding the region RA60 may be any known method, such as a method using a heat bar.

[0102] (3.4) Welding process In the welding process, as shown in FIG. 9C, the terminal 20A and the laminate sheet 30 are welded together with a heat bar 70 via the tab film 10A to form an inner excess resin portion 11 protruding from the end EA20 of the terminal 20A on the electrode body 40 side.

[0103] Specifically, a total of four heat bars 70 are simultaneously pressed against the entire periphery of each of both end portions RB60 in the front-to-rear direction (X-axis direction) of the laminate sheet 30 of the structure 60 from each of four directions: the top (positive Z-axis direction), bottom (negative Z-axis direction), left side (negative Y-axis direction), and right side (positive Y-axis direction). This causes the terminal 20A and the laminate sheet 30 to be welded together via the tab film 10A by the heat bars 70, forming an inner excess resin portion 11. Each of both end portions RB60 in the front-to-rear direction (X-axis direction) of the laminate sheet 30 of the structure 60 corresponds to the thermocompression-bonded portion 12 of the tab film 10A.

[0104] (3.4.1) Heat Bar In the first embodiment, the heat bar 70 has a flat portion 71 and an inclined portion 72, as shown in FIG. 10 . The flat portion 71 faces the terminal 20A via the laminate sheet 30 and the tab film 10A when the terminal 20A and the laminate sheet 30 are welded together. The inclined portion 72 is continuous with the flat portion 71 and is inclined toward the side opposite the terminal 20A (positive direction of the Z axis) relative to the flat portion 71. The inclined portion 72 includes a portion 720 that does not face the terminal 20A via the laminate sheet 30 and the tab film 10A when the terminal 20A and the laminate sheet 30 are welded together. The angle θC (see FIG. 10 ) of the inclined surface of the inclined portion 72 relative to the surface of the flat portion 71 that contacts the laminate sheet 30 is appropriately selected depending on the size of the laminated battery 1A, and is preferably 10 to 45 degrees.

[0105] (3.5) Action and Effect As described with reference to Figures 9A to 10, the manufacturing method of the laminated battery of the first embodiment includes a welding process in which the terminal 20A and the laminate sheet 30 are welded together with a heat bar 70 via a tab film 10A to form an inner excess resin portion 11 protruding from the end EA20 of the terminal 20A on the electrode body 40 side. This makes it possible to obtain a laminated battery 1A in which the structural reliability of the laminate sheet is excellent even when exposed to a high-temperature environment.

[0106] As described with reference to FIGS. 9A to 10, in the method for manufacturing a laminated battery according to the first embodiment, the heat bar 70 has a flat portion 71 and an inclined portion 72. As shown in FIG. If the heat bar 70 has a flat portion 71 but does not have an inclined portion 72, when welding the terminal 20A to the laminate sheet 30, the non-contact portion RB30 of the laminate sheet 30 is likely to warp upward (in the positive direction of the Z axis) as shown in Fig. 11 due to the difference in the linear thermal expansion coefficient between the tab film 10A and the metal layer 31 included in the laminate sheet 30. If the non-contact portion RB30 of the laminate sheet 30 warps upward, it is difficult to form the inner excess resin portion 11 having the covering portion R11 (see Figs. 3 and 4) that covers the end portion R20A of the opposing surface SA20 of the terminal 20A. On the other hand, in the first embodiment, when the terminal 20A and the laminate sheet 30 are welded together, warping of the non-contact specific portion RB30 (see FIG. 11) of the laminate sheet 30 is suppressed by the inclined portion 72 of the heat bar 70. This makes it easier to form an inner excess resin portion 11 having a covering portion R11 that covers the end portion R20A of the opposing surface SA20 of the terminal 20A. The manufacturing method for the laminate battery of the first embodiment produces a laminate battery 1A with superior safety and structural reliability.

[0107] (4) Second embodiment The laminated battery 1B of the second embodiment of the present disclosure is similar to the laminated battery 1A of the first embodiment, except that the ends of the terminals on the electrode body 40 side are chamfered. The laminated battery 1B includes a tab film 10A, a pair of terminals 20B, a laminated sheet 30, and an electrode assembly 40.

[0108] As shown in Fig. 12, terminal 20B has a chamfered end EA20 on the electrode body 40 side. In other words, terminal 20B has a chamfered surface SD20 that is continuous with opposing surface SA20. The angle θD (see Fig. 12) formed between an imaginary plane S that includes opposing surface SA20 of terminal 20A and chamfered surface SD20 is preferably 30 to 60 degrees.

[0109] As described with reference to FIG. 12, in the laminated battery 1B, the end EA20 of the terminal 20B on the electrode assembly 40 side is chamfered. As a result, the surface area of ​​the portion of the inner excess resin portion 11 that is not in contact with at least one of the terminal 20B and the laminate sheet 30 is larger than when the end EA20 of the terminal 20B on the electrode body 40 side is not chamfered. This further reduces the stress that the laminate sheet 30 experiences due to the volumetric expansion of the inner excess resin portion 11 when the laminate battery 1B is exposed to high temperatures. As a result, the laminate battery 1B has superior structural reliability of the laminate sheet 30 even when exposed to high-temperature environments.

[0110] (5) Third embodiment A laminated battery 1C of the third embodiment of the present disclosure is similar to the laminated battery 1A of the first embodiment, except that the tab film has an outer excess resin portion. The laminated battery 1C includes a tab film 10B, a pair of terminals 20A, a laminated sheet 30, and an electrode assembly 40.

[0111] As shown in Fig. 13, the tab film 10B has an inner excess resin portion 11, a thermocompression-bonded portion 12, a non-thermocompression-bonded portion 13, and an outer excess resin portion 14. The outer excess resin portion 14 protrudes from the entire periphery of the end EB20 of the terminal 20A on the electrode body 40 side. The inner excess resin portion 11 is not sandwiched between the terminal 20A and the laminate sheet 30. The inner excess resin portion 11, the thermocompression-bonded portion 12, the non-thermocompression-bonded portion 13, and the end EB20 opposite the electrode body 40 side are integral.

[0112] The outer excess resin portion 14 protrudes from the end EB20 of the terminal 20A opposite to the electrode body 40. The outer excess resin portion 14 is formed, for example, when the thermocompression-bonded portion 12 is formed by thermocompression bonding, by extruding the molten material of the tab film 10A toward the end EB20 of the terminal 20A opposite to the electrode body 40.

[0113] As described with reference to FIG. 13, in the laminated battery 1C, the tab film 10B further has an outer excess resin portion 14. As a result, when laminated batteries 1C are stacked, the presence of the outer excess resin portion 14 makes it difficult for one terminal 20A of an adjacent laminated battery 1C to come into physical contact with the other terminal 20A of the adjacent laminated battery 1C or the laminate sheet 30. In other words, the occurrence of a short circuit is more reliably prevented than when the tab film 10B does not have the outer excess resin portion 14. As a result, the safety and structural reliability of the laminated battery 1C are superior.

[0114] (6) Fourth embodiment A battery stack 2B according to the fourth embodiment of the present disclosure is similar to the battery stack 2A according to the first embodiment, except that the shape of the inter-battery connection terminals is different. As shown in Figure 14, the battery stack 2B includes multiple laminated batteries 1A and multiple inter-battery connection terminals 50B. The multiple inter-battery connection terminals 50B are electrically connected to terminals 20A, connecting the multiple laminated batteries 1A in series.

[0115] The inter-battery connection terminals 50B are components (bus bars) for electrically connecting the multiple laminated batteries 1A in series. The inter-battery connection terminal 50B has a first terminal component 51 and a second terminal component 52. The first terminal component 51 is an L-shaped bent plate-like member. The first terminal component 51 is electrically connected to one of a pair of terminals 20A included in a laminated battery 1A. Hereinafter, a laminated battery 1A electrically connected to the first terminal component 51 will be referred to as a "battery with first terminal component." The second terminal component 52 is an L-shaped bent plate-like member. The second terminal component 52 is electrically connected to one of a pair of terminals 20A included in a laminated battery 1A adjacent to the battery with the first terminal component, among multiple laminated batteries 1A. Hereinafter, a laminated battery 1A electrically connected to the second terminal component 52 will be referred to as a "battery with second terminal component." The first terminal component 51 and the second terminal component 52 are electrically connected. The first terminal component 51 is attached to the outer surface SC20 of the terminal 20A of the battery with the first terminal component. The second terminal component 52 is attached to the outer surface SC20 of the terminal 20A of the battery with the second terminal component. The first terminal component 51 is attached to the second terminal component 52. The method of attaching the first terminal component 51 and the second terminal component 52 is not particularly limited, and may be the same as the method exemplified as the method of attaching the inter-battery connection terminal 50A of the first embodiment.

[0116] As described with reference to Fig. 14, the battery stack 2B includes multiple laminate-type batteries 1A and multiple inter-battery connection terminals 50B, as shown in Fig. 14. The inter-battery connection terminals 50B include a first terminal component 51 and a second terminal component 52. This allows for better productivity of the battery stack 2B than when the inter-battery connection terminal 50B does not have the first terminal part 51 and the second terminal part 52.

[0117] (3) Variations In the first to fourth embodiments, the first angle θA is equal to or greater than 90 degrees, but may be less than 90 degrees. In the first to fourth embodiments, the second angle θB is equal to or greater than 90 degrees, but may be less than 90 degrees.

[0118] In the first to fourth embodiments, the length L4 (see FIG. 3) is at least half the thickness L5 (see FIG. 2), but may be less than half the thickness L5. In the first to fourth embodiments, the length L7 (see FIG. 4) is at least half the thickness L5 (see FIG. 2), but may be less than half the thickness L5 (see FIG. 2).

[0119] In the first to fourth embodiments, the length L4 (see FIG. 3) is 1 / 5 or more of the length L6 (see FIG. 3), but may be less than 1 / 5 of the length L6. In the first to fourth embodiments, the length L7 (see FIG. 4) is 1 / 5 or more of the length L8 (see FIG. 4), but may be less than 1 / 5 of the length L8.

[0120] In the first to fourth embodiments, the inner excess resin portion 11 protrudes from the entire circumference of the end EA20 of the terminal 20A on the electrode body 40 side, but it may also protrude from a portion of the entire circumference of the end EA20 of the terminal 20A on the electrode body 40 side.

[0121] In the first to fourth embodiments, the electrode assembly 40 has a plurality of unit electrode bodies 41, but may have a single unit electrode body 41. In the first to fourth embodiments, the unit electrode body 41 has a solid electrolyte layer, but a non-aqueous electrolyte solution may be used instead of the solid electrolyte layer.

[0122] In the first to fourth embodiments, the side surface members are terminals, but they do not have to be terminals. For example, the side surface members may be metal lids that do not function as terminals. The metal lids may have through holes for electrically connecting the terminals of the laminated battery to inter-battery connection terminals outside the laminated battery.

[0123] In the first to fourth embodiments, the opposing surfaces of the terminals are electrically connected to the electrode body, but the opposing surfaces of the terminals do not have to be electrically connected to the electrode body.

[0124] In the first to fourth embodiments, the pair of terminals face each other across the electrode body, but they do not have to face each other across the electrode body.

[0125] In the method for manufacturing a laminated battery according to the first embodiment, the heat bar has an inclined portion, but it does not have to have an inclined portion.

[0126] In the first to fourth embodiments, the laminated battery is a laminated lithium secondary battery using a solid electrolyte, but it may also be a secondary battery such as a nickel-metal hydride battery.

[0127] In the first to fourth embodiments, the terminals have a rectangular parallelepiped shape, but they do not have to have a rectangular parallelepiped shape.

[0128] In the first to fourth embodiments, the length L3 (see FIG. 2) is longer than the length L1 (see FIG. 2), but it may be the same as or shorter than the length L1.

[0129] In the first embodiment, the battery connection terminal is a single plate-like member, but the shape of the battery connection terminal is not limited as long as it connects multiple laminated batteries 1A in series. In the fourth embodiment, the first and second terminal components are each L-shaped plate-like members, but the shapes of the first and second terminal components are not particularly limited as long as they connect multiple laminated batteries 1A in series and electrically connect the first and second terminal components.

[0130] In the first to fourth embodiments, no non-thermocompression-bonded portion is interposed between the inner excess resin portion 11 and the thermocompression-bonded portion 12 in the front-rear direction (X-axis direction), but a non-thermocompression-bonded portion may be interposed between the inner excess resin portion 11 and the thermocompression-bonded portion 12. In other words, in the first to fourth embodiments, the position of the end of the thermocompression-bonded portion 12 in the negative X-axis direction is the same as the position of the end EA20 of the terminal 20A on the electrode body 40 side in the front-rear direction (X-axis direction), but they may be different. For example, the position of the end of the thermocompression-bonded portion 12 in the negative X-axis direction may be within 1 mm of the position of the end EA20 of the terminal 20A on the electrode body 40 side in the front-rear direction (X-axis direction). [Explanation of symbols]

[0131] 1A, 1B, 1C laminated battery 2A, 2B battery stack 10A, 10B tab film 11 Excess resin inside 20A, 20B terminals 30 Laminate Sheet 40 Electrode body

Claims

1. A laminated battery, An electrode body; a side surface member disposed on a side surface of the electrode body; a laminate sheet covering the electrode body; a tab film disposed between the side member and the laminate sheet; Equipped with the side surface member and the laminate sheet are welded together via the tab film, the tab film has an inner excess resin portion protruding from the end of the side surface member on the electrode body side, the side surface member has an opposing surface facing the side surface of the electrode body, In a cross section of the laminated battery cut along a direction perpendicular to the side surface of the electrode body, the angle formed between the opposing surface of the side surface member and a direction in which the laminate sheet extends from a specific portion of the laminate sheet toward the electrode body is 100 degrees or more and 150 degrees or less, The specific portion of the laminate sheet is a portion that intersects with an imaginary plane that includes the opposing surface of the side member.

2. the laminate sheet has a metal layer and a resin layer laminated on a surface of the metal layer facing the electrode body, the inner excess resin portion has a covering portion that covers an end portion of the opposing surface, 2. The laminated battery according to claim 1, wherein in a cross section of the laminated battery cut along a direction perpendicular to the side surface of the electrode body, the length of the covering portion from the end on the electrode body side in a direction parallel to the opposing surface of the side member is at least half the thickness of the resin layer.

3. the laminate sheet has a metal layer and a resin layer laminated on a surface of the metal layer facing the electrode body, the inner excess resin portion has a covering portion that covers an end portion of the opposing surface, 2. The laminated battery according to claim 1, wherein in a cross section of the laminated battery cut along a direction perpendicular to the side surface of the electrode body, the length of the covering portion from the end of the electrode body side in a direction parallel to the opposing surface of the side member is 1 / 5 or more of the length from the end of the electrode body side in a direction parallel to the opposing surface of the side member to the metal layer.

4. The laminated battery according to claim 1 , wherein the end of the side member facing the electrode body is chamfered.

5. 2. The laminated battery according to claim 1, wherein the tab film further has an outer excess resin portion protruding from an end of the side member opposite to the electrode body side.

6. The laminated battery according to claim 1 , wherein the inner excess resin portion protrudes from the entire periphery of the end of the side member on the electrode body side.

7. the electrode assembly includes at least one unit electrode assembly, 2. The laminated battery according to claim 1, wherein the unit electrode body is formed by laminating a positive electrode current collector, a positive electrode layer, an electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order.

8. the side member is a terminal, the terminal has an opposing surface facing the side surface of the electrode body, 8. The laminated battery according to claim 1, wherein the opposing surface is electrically connected to the electrode body.

9. The laminated battery according to claim 8 , comprising a pair of the terminals facing each other with the electrode body interposed therebetween.

10. a plurality of laminated batteries according to claim 9 stacked in a direction parallel to the side surfaces of the electrode bodies; a plurality of inter-battery connection terminals electrically connected to the terminals and connecting a plurality of the laminated batteries in series.

11. the plurality of laminated batteries include a first battery and a second battery adjacent to the first battery, the plurality of inter-battery connection terminals include a first inter-battery connection terminal that electrically connects the first battery and the second battery, The first inter-battery connection terminal is a first terminal component electrically connected to one of the pair of terminals included in the first battery; a second terminal component electrically connected to one of the pair of terminals included in the second battery; and The battery stack according to claim 10 , wherein the first terminal component and the second terminal component are electrically connected to each other.

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