Manufacturing method of laminate type battery

Abstract

To provide a manufacturing method of a laminate type battery, capable of reducing a difference in thickness generated depending on a place of a lamination film after deposition in contact with a side surface member.SOLUTION: A manufacturing method of a laminate type battery comprising an electrode body, a side surface member, and a laminate film covering the electrode body and the side surface member, the side surface member being arranged at a position inclined to a center of a side surface in a longer direction of the side surface, includes a deposition step of depositing the laminate film so as to cover part of the electrode body and the side surface member. When a region on the side where the side surface member is eccentrically arranged is an uneven side region A and the other region is a non-uneven side region B in the side surface member, with a center of the side surface member in the longer direction of the side surface as a boundary, a mean thickness a in contact with the uneven side region A of the side surface member is thicker than a mean thickness b of the region in contact with the non-uneven side region B of the side surface member in the laminate film used for the fusion step.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a laminated battery. [Background technology]

[0002] 2. Description of the Related Art Conventionally, laminate type batteries have been used which include an electrode body, a side member such as a terminal, and a laminate film which covers the electrode body and a portion of the side member.

[0003] For example, Patent Document 1 discloses a battery in which a terminal on one side surface is disposed offset to one side with respect to the center of the side surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-283611 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, laminated type batteries have been used that include an electrode body, a side member such as a terminal, and a laminate film that covers a part of the electrode body and the side member. In this laminated type battery, the side member may be disposed at a position offset to one side with respect to the center of the side in the longitudinal direction of the side. However, when a laminate film is welded to an electrode body in which the side member is biased toward one side of the side surface, differences in thickness may occur in different locations of the laminate film in the area in contact with the side member.

[0006] The present disclosure has been made in consideration of the above-described situation, and aims to provide a manufacturing method for a laminated battery that can reduce thickness differences that occur at different locations in a laminate film that is in contact with a side member after welding. [Means for solving the problem]

[0007] Means for solving the above problems include the following aspects. <1> An electrode body; A side member disposed on a side surface of the electrode body; a laminate film covering the electrode body and a portion of the side surface member, A method for manufacturing a laminated battery, wherein the side surface member is disposed at a position offset to one side with respect to a center of the side surface in a longitudinal direction of the side surface, a welding step of welding the laminate film so as to cover the electrode body and a portion of the side surface member, In the side surface member, when a region on the side where the side surface member is biased is defined as a biased-distribution side region A and the other region is defined as a non-biased-distribution side region B, the center of the side surface member in the longitudinal direction of the side surface is defined as a boundary, the laminate film used in the welding step has an average thickness a of a region that contacts the uneven distribution side region A of the side member which is thicker than an average thickness b of a region that contacts the non-uneven distribution side region B of the side member. <2> The thickness of the laminate film used in the welding step in a region in contact with the side surface member is continuously increased toward the side where the side surface member is biasedly disposed in the longitudinal direction of the side surface. <1> A method for producing the laminated battery according to claim 1. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a manufacturing method for a laminated battery that can reduce differences in thickness that occur depending on the location of a laminate film that is in contact with a side member after welding. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic perspective view showing an electrode body and a side member before a welding step is performed in a manufacturing method for a laminated battery according to an embodiment of the present disclosure. [Diagram 2]FIG. 2 is a schematic side view, viewed from the side, showing a state before welding is performed in a welding step in a manufacturing method for a laminated battery according to an embodiment of the present disclosure. [Diagram 3] FIG. 2 is a schematic plan view showing a main part of the vehicle. [Figure 4] FIG. 2 is a schematic perspective view of a battery module. [Diagram 5] FIG. 2 is a plan view of the battery module with the top cover removed. [Figure 6] 2 is a schematic diagram of a battery cell accommodated in a battery module as viewed from the thickness direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment that is an example of the present disclosure will be described below. These descriptions are for illustrating the embodiment and are not intended to limit the scope of the invention. In addition, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the process achieves its intended effect.

[0011] <Laminated battery manufacturing method> A manufacturing method for a laminated battery according to an embodiment of the present disclosure manufactures a laminated battery comprising an electrode body, a side member arranged on a side of the electrode body, and a laminate film covering the electrode body and a portion of the side member, wherein the side member is arranged in a position offset to one side with respect to the center of the side in the longitudinal direction of the side. This manufacturing method includes a step of welding a laminate film so as to cover the electrode body and a portion of the side member. In the side member, when the center of the side member in the longitudinal direction of the side is taken as the boundary, the region on the side where the side member is biased is taken as biased side region A, and the other region is taken as non-biased side region B, the laminate film used in the welding process has an average thickness a of the region adjacent to biased side region A of the side member that is thicker than the average thickness b of the region adjacent to non-biased side region B of the side member.

[0012] Here, a method for manufacturing a laminated battery according to an embodiment of the present disclosure will be described with reference to the drawings. The drawings shown below are schematic diagrams, and the size and shape of each part are appropriately exaggerated to make them easier to understand.

[0013] Fig. 1 is a schematic perspective view showing an electrode body and a side member before a welding step is performed in a manufacturing method for a laminated battery according to an embodiment of the present disclosure. Fig. 2 is a schematic side view seen from a side direction (the direction of the surface on which the side member is arranged, the Z direction in Fig. 2) showing a state before welding is performed in a welding step in a manufacturing method for a laminated battery according to an embodiment of the present disclosure.

[0014] 1, in the manufacturing method of a laminated battery according to an embodiment of the present disclosure, the electrode body 4 used in the welding step (i.e., before the welding step is performed) has terminals 26 as an example of a side surface member arranged on each of a pair of side surfaces 4A. Note that on the side surface 4A of the electrode body 4, there are two regions 41A and 42A in which the terminal 26 is not arranged, on both sides of the terminal 26 in the longitudinal direction of the side surface 4A (the direction of the arrow X). The terminal 26 is disposed in a position offset to one side (offset to the right in Figs. 1 and 2) with respect to the center Lc1 of the side 4A in the longitudinal direction (arrow X direction) of the side 4A of the electrode body 4. Therefore, on the side 4A of the electrode body 4, a region 42A where the terminal 26 is not disposed on the side where the terminal 26 is offset has a larger area than the other side, and a region 41A on the other side has a smaller area. In the following description, of the two regions on the side surface of the electrode body where no side surface member is arranged, the region with a larger area is referred to as the "wide region" and the region with a smaller area is referred to as the "narrow region."

[0015] In the welding step in the manufacturing method of the laminated battery according to the embodiment of the present disclosure, as shown in FIG. 2, the laminate film 28 is arranged so as to cover the electrode body 4 and a part of the terminal 26. Note that FIG. 2 shows a state before welding in the welding step. The laminate film 28 is arranged so as to cover the entire surface of the electrode body 4, and the entire area of ​​the side surface 4A of the electrode body 4 where the terminal 26 is not provided is covered with the laminate film 28 (therefore, the electrode body 4 covered with the laminate film 28 is shown by a dotted line in FIG. 2). In addition, the laminate film 28 is arranged so as to cover a part of each of the upper surface 26B, one side surface 26C, the lower surface 26D, and the other side surface 26E of the terminal 26, more specifically, the area on the electrode body 4 side on these four surfaces. Therefore, the entire outer surface 26A of the terminal 26, as well as the upper surface 26B, one side surface 26C, the lower surface 26D, and the area of ​​the other side surface 26E opposite the electrode body 4 are not covered by the laminate film 28 and are exposed.

[0016] The laminate film 28 used in the welding process (i.e., before the welding process) has different thicknesses depending on the location. Here, with respect to the terminals 26, the center Lc2 of the terminals 26 in the longitudinal direction (arrow X direction) of the side surface 4A is used as the boundary, and the region on the side where the terminals 26 are unevenly arranged (i.e., the narrow region 42A side) is the uneven distribution side region A, and the region on the opposite side to the side where the terminals 26 are unevenly arranged (i.e., the wide region 41A side) is the non-uneven distribution side region B. In this case, the laminate film 28 used in the welding process has an average thickness a of the region in contact with the uneven distribution side region A of the terminals 26 that is thicker than the average thickness b of the region in contact with the non-uneven distribution side region B of the terminals 26.

[0017] In this disclosure, the average thickness a of the region of the laminate film that contacts the uneven-distribution side region A of the side member means the average thickness of the laminate film in the region that contacts the uneven-distribution side region A on two faces parallel to the longitudinal direction of the side of the electrode body (two faces, upper surface 26B and lower surface 26D of terminal 26 in FIG. 1) out of the four faces with which the laminate film contacts on the side member (four faces in FIG. 1: upper surface 26B, one side surface 26C, lower surface 26D, and the other side surface 26E). The average thickness b of the region of the laminate film that contacts the non-uniform distribution side region B of the side member means the average thickness of the laminate film in the region that contacts the non-uniform distribution side region B on two of the four surfaces of the side member that are parallel to the longitudinal direction of the side of the electrode body with which the laminate film contacts.

[0018] Thus, in the manufacturing method of a laminated battery according to an embodiment of the present disclosure, in the laminate film used in the welding step, the average thickness a of the region in contact with the uneven-distribution-side region A of the side member is greater than the average thickness b of the region in contact with the non-uneven-distribution-side region B of the side member. With this configuration, it is possible to reduce thickness differences that occur depending on the location of the laminate film in contact with the side member after welding.

[0019] Conventionally, laminated batteries have been used that include an electrode body, a side member such as a terminal, and a laminate film that covers part of the electrode body and the side member. In this laminated battery, the side member may be positioned to one side with respect to the center of the side in the longitudinal direction of the side (the X direction in Figs. 1 and 2) due to the arrangement of the battery in a battery module.

[0020] Here, in manufacturing a laminated battery, when sealing the electrode body and a part of the side surface member with a laminate film, a process of welding the laminate film to cover the electrode body and a part of the side surface member is carried out. For example, at the location where the laminate film contacts the side surface member, a heated welding member is pressed against the side surface member through the laminate film to melt the inner surface of the laminate film (the side contacting the side surface member), thereby welding the laminate film to the side surface member.

[0021] However, when the laminate film is welded to an electrode body in which the side surface member is biased to one side on the side surface, the laminate film in the region in contact with the side surface member may have a difference in thickness depending on the location. Specifically, in the laminate film in the region in contact with the side surface member, the thickness of the laminate film is thin in the biased side region A (i.e., the narrow region side (region 42A side in Figs. 1 and 2)), while the thickness of the laminate film is thick in the non-biased side region B (i.e., the wide region side (region 41A side in Figs. 1 and 2)). The reason for this is presumed to be as follows. The heat applied to the laminate film when welding the laminate film to the side member is also absorbed by the side member and the electrode body, so not all of the applied heat contributes to melting the inner surface of the laminate film. In an electrode body in which the side member is arranged biased to one side on the side of the electrode body, it is considered that a difference occurs in the amount of heat absorbed by the electrode body between one side and the other side of the side member in the longitudinal direction of the side (X direction in Figures 1 and 2). In other words, it is considered that, on the side of the electrode body, the amount of heat absorbed by the electrode body when welding the laminate film is greater in the side member closer to the wide area (i.e., non-biased side area B), and less in the side member closer to the narrow area (i.e., biased side area A). This is presumably because the volume of the electrode body that contributes to heat absorption on the wide area side (i.e., the volume of the electrode body that exists in the vicinity of the non-uniform side area B of the side member) is larger than the volume of the electrode body that contributes to heat absorption on the narrow area side (i.e., the volume of the electrode body that exists in the vicinity of the uneven side area A of the side member). In addition, in the laminate film in contact with the non-uniform side area B of the side member, the amount of heat absorbed by the electrode body is large, so the amount of heat that contributes to melting the inner surface of the laminate film is small, and the amount of melting is reduced, resulting in a thicker laminate film after welding. On the other hand, in the laminate film in contact with the uneven side area A of the side member, the amount of heat absorbed by the electrode body is small, so the amount of heat that contributes to melting the inner surface of the laminate film is large, and the amount of melting is increased, resulting in a thinner laminate film after welding. It is presumed that the above mechanism causes differences in thickness depending on the location in the laminate film after welding in the area in contact with the side member.

[0022] Therefore, in the manufacturing method of the laminated battery according to the embodiment of the present disclosure, the average thickness a of the region of the laminate film used in the welding step that contacts the uneven distribution side region A of the side member is made thicker than the average thickness b of the region of the laminate film that contacts the non-uneven distribution side region B of the side member. That is, in the region of the laminate film that contacts the side member, the thickness of the region (i.e., uneven distribution side region A) on the narrow region side (right side in Figs. 1 and 2) corresponding to the side that will become thicker after welding is adjusted to be thin in advance, and the thickness of the region (i.e., non-uneven distribution side region B) on the wide region side (left side in Figs. 1 and 2) corresponding to the side that will become thinner after welding is adjusted to be thick in advance. In this way, by adjusting the thickness of the region of the laminate film that contacts the side member in advance, it is possible to offset the difference in thickness in the laminate film after welding that occurs due to the difference in the amount of heat absorbed by the electrode body. As a result, it is possible to reduce the difference in thickness that occurs depending on the location in the laminate film after welding that contacts the side member.

[0023] In addition, in the manufacturing method of the laminated battery according to the embodiment of the present disclosure, it is preferable that the thickness of the laminate film used in the welding process in the region in contact with the side member continuously increases toward the side where the side member is biasedly arranged in the longitudinal direction of the side surface.

[0024] 2, the thickness of the region in contact with the terminals 26 increases continuously in the longitudinal direction of the side surface 4A (X direction in FIG. 2) from the wide region 41A side toward the narrow region 42A side (i.e., the side where the terminals 26 are biasedly disposed). Therefore, in the region in contact with the terminals 26 of the laminate film 28, when comparing the thickness 28a of the portion 28A, the thickness 28b of the portion 28B, the thickness 28c of the portion 28C, and the thickness 28d of the portion 28D in order from the side closer to the wide region 41A, the thicknesses increase in the order of "28a<28b<28c<28d".

[0025] In this way, in the laminate film used in the welding process, the thickness in the area in contact with the side member becomes continuously thicker toward the side where the side member is biasedly positioned in the longitudinal direction of the side, so that the thickness difference that occurs at different locations in the laminate film after welding in contact with the side member can be further reduced.

[0026] Here, a configuration will be described in which the thickness of the laminate film in the region in contact with the side member is continuously thickened toward the side where the side member is biased in the longitudinal direction of the side will be described. The "thickness" referred to here means the thickness of the laminate film in the region in contact with the side member on two faces (two faces, the upper face 26B and the lower face 26D of the terminal 26 in FIG. 1) parallel to the longitudinal direction of the side of the electrode body out of the four faces (four faces, the upper face 26B, one side face 26C, the lower face 26D, and the other side face 26E of the terminal 26 in FIG. 1) with which the laminate film is in contact. Therefore, it is sufficient that the thickness of the laminate film in the region in contact with the side member on two faces (the upper face 26B and the lower face 26D in FIG. 1) parallel to the longitudinal direction of the side may be continuously thickened toward the side where the side member is biased (i.e., the narrow region side).

[0027] However, in the manufacturing method of the laminated battery according to the embodiment of the present disclosure, the laminate film used in the welding step does not have to have a thickness in the region in contact with the side surface member that increases continuously toward the side where the side surface member is biased in the longitudinal direction of the side surface. For example, the thickness of the laminate film in the region in contact with the side surface member may increase stepwise toward the side where the side surface member is biased in the longitudinal direction of the side surface (i.e., the thickness gradually increases in a stepped manner).

[0028] (Measurement method) Here, a method for measuring the average thickness a of the region of the laminate film in contact with the uneven distribution side region A of the lateral member and the average thickness b of the region of the laminate film in contact with the non-uneven distribution side region B of the lateral member will be described. As described above, the average thickness a of the laminate film in contact with the uneven distribution side region A of the side member means the average thickness of the laminate film in the region that contacts the uneven distribution side region A on two of the four faces of the side member that are parallel to the longitudinal direction of the side of the electrode body with which the laminate film is in contact. Also, the average thickness b of the laminate film in contact with the non-uneven distribution side region B of the side member means the average thickness of the laminate film in the region that contacts the non-uneven distribution side region B on two of the four faces of the side member that are parallel to the longitudinal direction of the side of the electrode body with which the laminate film is in contact.

[0029] The average thickness a is the arithmetic mean value of the thickness of the laminate film in the region that contacts the uneven distribution side region A on two of the four surfaces of the side member that are parallel to the longitudinal direction of the side of the electrode body, which are in contact with the laminate film, measured at any ten points. On the other hand, the average thickness b is the arithmetic mean value of the thickness of the laminate film in the region that contacts the non-uneven distribution side region B on two of the four surfaces of the side member that are parallel to the longitudinal direction of the side of the electrode body, which are in contact with the laminate film, measured at any ten points.

[0030] Next, a battery module, a battery pack, and a vehicle having a laminated battery manufactured by the manufacturing method for a laminated battery according to an embodiment of the present disclosure will be described with reference to the drawings.

[0031] (Overall configuration of vehicle 100) Fig. 3 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. As shown in Fig. 3, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) in which the battery pack 10 is mounted under the floor. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle vertical direction, the front side in the vehicle longitudinal direction, and the left side in the vehicle width direction, respectively. When describing using the front-rear, left-right, up-down directions, they refer to the front-rear in the vehicle longitudinal direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0032] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are disposed on the vehicle front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are disposed on the vehicle rear side of the battery pack 10.

[0033] The direct current output from the battery pack 10 has its voltage adjusted by a DC / DC converter 102, and is then supplied to an electric compressor 104, a PTC heater 106, an inverter 112, etc. In addition, power is supplied to a motor 108 via the inverter 112, causing the rear wheels to rotate and causing the vehicle 100 to run.

[0034] A charging port 116 is provided on the right side at the rear of the vehicle 100, and by connecting a charging plug of an external charging facility (not shown) to the charging port 116, power can be stored in the battery pack 10 via the charger 114.

[0035] The arrangement and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle in which the motor 108 is mounted at the rear of the vehicle, but the present invention is not limited to this. The vehicle may be a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, the vehicle may be equipped with an in-wheel motor on each wheel.

[0036] Here, the battery pack 10 is configured to include a plurality of battery modules 11. As an example in this embodiment, ten battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle front-rear direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle front-rear direction. In addition, each battery module 11 is electrically connected.

[0037] Fig. 4 is a schematic perspective view of the battery module 11. As shown in Fig. 4, the battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is formed of an aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die castings to both ends of an aluminum alloy extrusion material by laser welding or the like.

[0038] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 22, which will be described later, is connected to the connector 14. In addition, bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0039] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle up-down direction is, for example, 80 mm to 110 mm.

[0040] Fig. 5 is a plan view of the battery module 11 with the top cover removed. As shown in Fig. 5, a plurality of battery cells 20 are housed in an arranged state inside the battery module 11. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to one another.

[0041] A flexible printed circuit (FPC) 22 is disposed on the battery cells 20. The flexible printed circuit 22 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and a thermistor 24 is provided on each of both ends of the flexible printed circuit 22. The thermistor 24 is not bonded to the battery cells 20, and is configured to be pressed towards the battery cells 20 by the upper lid of the battery module 11.

[0042] One or more cushioning materials (not shown) are housed inside the battery module 11. For example, the cushioning materials are elastically deformable thin plate-like members, and are arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 being the thickness direction. As an example in this embodiment, cushioning materials are arranged at both ends of the battery module 11 in the longitudinal direction and in the central portion in the longitudinal direction.

[0043] Fig. 6 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 6, the battery cell 20 is formed in a substantially rectangular plate shape, and houses an electrode body (not shown) inside. The electrode body is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 28.

[0044] In this embodiment, as an example, the housing portion for the electrode body is formed by folding and pasting an embossed sheet-like laminate film 28. Note that although both a single cup embossed structure in which embossing is performed at one place and a double cup embossed structure in which embossing is performed at two places can be adopted, the present embodiment adopts a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0045] The upper ends of the battery cells 20 at both ends in the longitudinal direction are bent to form corners. The upper end of the battery cells 20 is also bent, and a fixing tape 30 is wound around the upper end of the battery cells 20 along the longitudinal direction.

[0046] Here, terminals (tabs) 26 are provided at both longitudinal ends of the battery cell 20. In this embodiment, as an example, the terminals 26 are provided at positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to a bus bar (not shown) by laser welding or the like.

[0047] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, the length CW2 of the region in which the electrode body is housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm, 110 mm to 140 mm. The thickness of the battery cell 20 is 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, 9.0 mm to 11.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm, 50 mm to 60 mm, 60 mm to 70 mm. [Explanation of symbols]

[0048] 4 electrode body, 10 battery pack, 11 battery module, 12 voltage terminal, 14 connector, 20 battery cell, 22 flexible printed circuit board, 24 thermistor, 26 terminal, 28 laminate film, 30 fixing tape, 41A, 42A area, 100 vehicle, 102 converter, 104 electric compressor, 106 heater, 108 motor, 110 gear box, 112 inverter, 114 charger, 116 charging port

Claims

1. An electrode body; A side member disposed on a side surface of the electrode body; a laminate film covering the electrode body and a portion of the side surface member, A method for manufacturing a laminated battery, wherein the side surface member is disposed at a position offset to one side with respect to a center of the side surface in a longitudinal direction of the side surface, a welding step of welding the laminate film so as to cover the electrode body and a portion of the side surface member, In the side surface member, when a region on the side where the side surface member is biased is defined as a biased-distribution side region A and the other region is defined as a non-biased-distribution side region B, the center of the side surface member in the longitudinal direction of the side surface is defined as a boundary, the laminate film used in the welding step has an average thickness a of a region that contacts the uneven distribution side region A of the side member which is thicker than an average thickness b of a region that contacts the non-uneven distribution side region B of the side member.

2. 2. The method for manufacturing a laminated battery according to claim 1, wherein the thickness of the laminate film used in the welding step in the region in contact with the side member increases continuously toward the side to which the side member is biasedly arranged in the longitudinal direction of the side surface.

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