Manufacturing method of laminated battery, and laminated battery

Abstract

To provide a method for manufacturing a laminated battery that can suppress differences in thickness from occurring depending on the location of a laminate film that is in contact with a side member after welding.SOLUTION: A method for manufacturing a laminated battery that includes 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, and in which the side member is arranged at a position offset to one side with respect to the center of the side in the longitudinal direction of the side, includes a step of welding the laminate film so as to cover the electrode body and a portion of the side member, and the side member has a shape whose thickness continuously increases toward the side to which the side member is offset.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a laminated battery, and 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, thickness differences can 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 method for manufacturing a laminated battery that can suppress differences in thickness between locations of a laminate film in contact with a side member after welding, and a laminated battery in which differences in thickness between locations of a laminate film in contact with a side member are suppressed. [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, The method includes a step of welding the laminate film so as to cover the electrode body and a portion of the side surface member, The method for manufacturing a laminated battery, wherein the side surface member has a shape such that the thickness continuously increases toward the side on which the side surface member is biasedly arranged. <2> 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, The side surface member is disposed at a position offset to one side with respect to the center of the side surface in the longitudinal direction of the side surface, The side surface member has a shape such that the thickness increases continuously toward the side on which the side surface member is biased. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a manufacturing method for a laminated battery that can suppress differences in thickness between locations of a laminate film in contact with a side member after welding, and a laminated battery in which differences in thickness between locations of a laminate film in contact with a side member are suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic perspective view showing a laminated battery manufactured by a manufacturing method for a laminated battery according to an embodiment of the present disclosure, and an electrode body and a side member provided in the laminated battery according to an embodiment of the present disclosure. [Diagram 2] 1 is a schematic side view of a laminated battery manufactured by a manufacturing method for a laminated battery according to an embodiment of the present disclosure, and a laminated battery according to an embodiment of the present disclosure, as viewed from the side; FIG. [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] 3 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 and laminated battery> A manufacturing method for a laminated battery according to an embodiment of the present disclosure relates to a manufacturing method for 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. The side surface member has a shape such that the thickness increases continuously toward the side on which the side surface member is biasedly disposed.

[0012] A laminated battery according to an embodiment of the present disclosure comprises an electrode body, a side member arranged on a side of the electrode body, and a laminate film covering a portion of the electrode body and the side member, and 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. The side surface member has a shape such that the thickness increases continuously toward the side on which the side surface member is biasedly disposed.

[0013] Here, a laminated battery manufactured by the manufacturing method for a laminated battery according to an embodiment of the present disclosure and 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.

[0014] Fig. 1 is a schematic perspective view showing a laminated battery manufactured by a manufacturing method for a laminated battery according to an embodiment of the present disclosure, and an electrode body and a side member included in the laminated battery according to an embodiment of the present disclosure. Fig. 2 is a schematic side view of a laminated battery manufactured by a manufacturing method for a laminated battery according to an embodiment of the present disclosure, and a laminated battery according to an embodiment of the present disclosure, as viewed from a side direction (the direction of the surface on which the side member is arranged, the Z direction in Figs. 1 and 2).

[0015] 1 and 2, a battery (battery cell) 20 which is an example of a laminated battery, has an electrode body 4 and terminals 26 as an example of side surface members which are arranged on each of a pair of side surfaces 4A of the electrode body 4. 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 either side of the terminal 26 in the longitudinal direction (direction of arrow X) of the side surface 4A. 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 Lc of the side 4A in the longitudinal direction (direction of arrow X) 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."

[0016] As shown in FIG. 2, the battery (battery cell) 20 includes a laminate film 28 that covers the electrode body 4 and a part of the terminal 26. The laminate film 28 covers 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, in FIG. 2, the electrode body 4 covered with the laminate film 28 is shown by a dotted line). The laminate film 28 is also arranged with respect to the terminal 26 so as to cover parts of the upper surface 26B, one side surface 26C, lower surface 26D, and other side surface 26E of the terminal 26, more specifically, the areas on the electrode body 4 side of these four surfaces. Therefore, the entire surface of the outer side surface 26A of the terminal 26 and the areas of the upper surface 26B, one side surface 26C, lower surface 26D, and other side surface 26E opposite the electrode body 4 are not covered by the laminate film 28 and are exposed.

[0017] The terminal 26 has a shape in which the thickness increases continuously toward the side where the terminal 26 is biasedly arranged. That is, of the two regions 41A and 42A in the side surface 4A of the electrode body 4 where the terminal 26 is not arranged, the thickness of the terminal 26 increases continuously from the region 41A having a larger area (wide region) toward the region 42A having a smaller area (narrow region).

[0018] 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.

[0019] 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.

[0020] However, when a laminate film is welded to an electrode body in which a side surface member is arranged 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, the thickness of the laminate film in the region in contact with the side surface member is thin in the region close to the side where the side surface member is arranged biased (i.e., the narrow area side of the side surface of the electrode body (area 42A side in Figures 1 and 2)). On the other hand, the thickness of the laminate film in the region in contact with the side surface member is thick in the region close to the opposite side to the side where the side surface member is arranged biased (i.e., the wide area side of the side surface of the electrode body (area 41A side in Figures 1 and 2)). The reason for this is presumed to be as follows. Here, a case will be described in which the side member is arranged biased to one side on the side of the electrode body, and the shape of the side member is a rectangular parallelepiped (i.e., the thickness does not change toward one side, but is constant). Since 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, not all of the applied heat contributes to melting the inner surface of the laminate film. In addition, 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 the amount of heat absorbed by the electrode body is greater in the side member closer to the wide area when welding the laminate film on the side of the electrode body, and the amount of heat absorbed by the electrode body is smaller in the side member closer to the narrow area. 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 side member on the wide area side) 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 side member on the narrow area side). In addition, in the laminate film that contacts the side member on the wide area side (left side in Figs. 1 and 2), 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 that contacts the side member on the narrow area side (right side in Figs. 1 and 2), 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 that contacts the side member.

[0021] Therefore, in the laminated battery manufacturing method and laminated battery according to the embodiment of the present disclosure, the shape of the side member is such that the thickness is continuously increased toward the side where the side member is biased (i.e., from the wide area side toward the narrow area side (the right side in Figs. 1 and 2)). This reduces the volume of the side member itself on the wide area side (the left side in Figs. 1 and 2) and reduces the area of ​​the contact surface between the side member and the electrode body, while increasing the volume of the side member itself on the narrow area side (the left side in Figs. 1 and 2) and increases the area of ​​the contact surface between the side member and the electrode body. Therefore, in the laminated film in contact with the side member on the wide area side, the amount of heat absorbed by the side member and the electrode body can be reduced. In addition, in the laminated film in contact with the side member on the narrow area side, the amount of heat absorbed by the side member and the electrode body can be increased. As a result, the amount of heat contributing to melting the inner surface of the laminate film during welding can be homogenized in the laminate film in contact with the side member on the wide area side and the laminate film in contact with the side member on the narrow area side, and the thickness difference depending on the location in the laminate film after welding in the area in contact with the side member can be suppressed.

[0022] Next, a laminated battery manufactured by the manufacturing method for a laminated battery according to an embodiment of the present disclosure, and a battery module, a battery pack, and a vehicle having a laminated battery according to an embodiment of the present disclosure will be described with reference to the drawings.

[0023] (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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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]

[0040] 4 electrode body, 10 battery pack, 11 battery module, 12 voltage terminal, 14 connector, 20 battery cell (battery), 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, The method includes a step of welding the laminate film so as to cover the electrode body and a portion of the side surface member, The method for manufacturing a laminated battery, wherein the side surface member has a shape such that the thickness increases continuously toward the side on which the side surface member is biasedly disposed.

2. 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, The side surface member is disposed at a position offset to one side with respect to the center of the side surface in the longitudinal direction of the side surface, The side surface member has a shape such that the thickness increases continuously toward the side on which the side surface member is biased.

Images