Method for manufacturing laminated batteries, and laminated batteries

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 Art

[0002] Conventionally, a laminated battery including an electrode body, side members such as terminals, and a laminated film covering a part of the electrode body and the side members has been used.

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventionally, a laminated battery including an electrode body, side members such as terminals, and a laminated film covering a part of the electrode body and the side members has been used. And in this laminated battery, the side member may be disposed at a position offset to one side with respect to the center in the longitudinal direction of the side surface. However, when the laminated film is welded to the electrode body in which the side member is disposed offset to one side on the side surface, a difference in thickness may occur in the laminated film in the region contacting the side member depending on the location.

[0006] This disclosure has been made in view of the above circumstances, and aims to provide a method for manufacturing a laminated battery that can suppress differences in thickness depending on the location in the laminated film that is in contact with the side members after welding, and a laminated battery in which differences in thickness depending on the location in the laminated film that is in contact with the side members are suppressed. [Means for solving the problem]

[0007] The means for solving the above problems include the following embodiments. <1> Electrode body and A side member arranged on the side of the electrode body, The device comprises a laminate film that covers the electrode body and a part of the side member, A method for manufacturing a laminated battery, wherein the side member is positioned in the longitudinal direction of the side at a location offset to one side with respect to the center of the side, The process includes a step of welding the laminate film so as to cover the electrode body and a portion of the side member, A method for manufacturing a laminated battery, wherein the side member has a shape in which the thickness increases continuously toward the side where the side member is positioned unevenly. <2> Electrode body and A side member arranged on the side of the electrode body, The device comprises a laminate film covering the electrode body and a portion of the side member, The side member is positioned in a location that is offset to one side with respect to the center of the side in the longitudinal direction of the side, The aforementioned side members have a shape in which the thickness increases continuously toward the side where the side members are positioned unevenly, in a laminated battery. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a method for manufacturing a laminated battery that can suppress differences in thickness depending on the location in the laminated film that is in contact with the side members after welding, and a laminated battery in which differences in thickness depending on the location in the laminated film that is in contact with the side members are suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing a laminated battery manufactured by the manufacturing method of a laminated battery according to an embodiment of this disclosure, and an electrode body and side members provided in the laminated battery according to an embodiment of this disclosure. [Figure 2] This is a schematic side view of a laminated battery manufactured by the manufacturing method of a laminated battery according to the embodiment of this disclosure, and a laminated battery according to the embodiment of this disclosure, viewed from the side. [Figure 3] This is a schematic plan view showing the main parts of the vehicle. [Figure 4] This is a schematic perspective view of the battery module. [Figure 5] This is a plan view of the battery module with the top cover removed. [Figure 6] This is a schematic diagram showing a battery cell housed in a battery module, viewed from the thickness direction. [Modes for carrying out the invention]

[0010] An example of an embodiment of this disclosure will be described. These descriptions are illustrative of embodiments and do not limit the scope of the invention. Furthermore, the term "process" includes not only independent processes, but also any process that cannot be clearly distinguished from other processes, as long as its intended function is achieved.

[0011] <Manufacturing method for laminated batteries and laminated batteries> The manufacturing method of a laminated battery according to an embodiment of the present disclosure includes an electrode body, a side member disposed on the side surface of the electrode body, and a laminate film covering the electrode body and a part of the side member, and relates to a manufacturing method of a laminated battery in which the side 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. This manufacturing method has a step of welding a laminate film so as to cover the electrode body and a part of the side member. The side member has a shape in which the thickness continuously increases toward the side where the side member is disposed offset.

[0012] A laminated battery according to an embodiment of the present disclosure includes an electrode body, a side member disposed on the side surface of the electrode body, and a laminate film covering the electrode body and a part of the side member, and the side 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 member has a shape in which the thickness continuously increases toward the side where the side member is disposed offset.

[0013] Here, the laminated battery manufactured by the manufacturing method of the laminated battery according to the embodiment of the present disclosure and the laminated battery according to the embodiment of the present disclosure will be described with reference to the drawings. Each of the drawings shown below is schematically illustrated, and the size and shape of each part are exaggerated as appropriate for easy understanding.

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

[0015] The battery (battery cell) 20, an example of a laminated battery shown in Figures 1 and 2, has an electrode body 4 and terminals 26, which are an example of side members, arranged on a pair of side surfaces 4A of the electrode body 4. On the side surface 4A of the electrode body 4, there are two regions 41A and 42A on either side of the terminal 26 in the longitudinal direction of the side surface 4A (arrow X direction), where the terminal 26 is not located. Terminal 26 is positioned on the side surface 4A of the electrode body 4 in a position that is offset to one side (offset to the right in Figures 1 and 2) relative to the center Lc of the side surface 4A in the longitudinal direction (arrow X direction). Therefore, on the side surface 4A of the electrode body 4, the area 42A where terminal 26 is not located on the side where terminal 26 is offset is larger in area than the other side, and the area 41A on the other side is smaller in area. In the following, of the two regions on the side of the electrode body where no side members are placed, the region with the larger area will be referred to as the "wide region," and the region with the smaller area will be referred to as the "narrow region."

[0016] As shown in Figure 2, the battery (battery cell) 20 is equipped with a laminate film 28 that covers the electrode body 4 and a portion of the terminal 26. The laminate film 28 covers the entire surface of the electrode body 4, and all areas on the side surface 4A of the electrode body 4 where the terminal 26 is not provided are covered by the laminate film 28 (therefore, in Figure 2, the electrode body 4 covered by the laminate film 28 is shown with a dotted line). In addition, the laminate film 28 is positioned to cover 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 areas on the electrode body 4 side of these four surfaces. Consequently, the entire outer surface 26A of the terminal 26, and the areas on the upper surface 26B, one side surface 26C, the lower surface 26D, and the other side surface 26E that are opposite to the electrode body 4 are not covered by the laminate film 28 and are exposed.

[0017] Furthermore, the terminal 26 has a shape in which its thickness continuously increases toward the side where the terminal 26 is positioned unevenly. In other words, of the two regions 41A and 42A on the side surface 4A of the electrode body 4 where the terminal 26 is not positioned, the thickness of the terminal 26 continuously increases toward the smaller region (narrow region) 42A.

[0018] Conventionally, laminated batteries have been used, which comprise an electrode body, side members such as terminals, and a laminate film that covers part of the electrode body and side members. In these laminated batteries, depending on the arrangement of the batteries within the battery module, the side members may be positioned off-center to one side in the longitudinal direction of the side (the X direction in Figures 1 and 2).

[0019] In the manufacturing of laminate-type batteries, when sealing the electrode body and a portion of the side member with a laminate film, a process is carried out to weld the laminate film so as to cover the electrode body and a portion of the side member. For example, at the point where the laminate film contacts the side member, a heated welding member is pressed against the side member through the laminate film, melting the inner surface of the laminate film (the side in contact with the side member) and welding the laminate film to the side member.

[0020] However, when a laminate film was welded to an electrode body in which the side members were positioned unevenly on one side, differences in thickness sometimes occurred in the laminate film in the area in contact with the side members. Specifically, in the area of ​​the laminate film in contact with the side members, the thickness of the laminate film was thinner in the area closer to the side where the side members were positioned unevenly (i.e., the narrow area on the side of the electrode body (area 42A in Figures 1 and 2)). On the other hand, in the area of ​​the laminate film in contact with the side members, the thickness of the laminate film was thicker in the area closer to the opposite side from the side where the side members were positioned unevenly (i.e., the wide area on the side of the electrode body (area 41A in Figures 1 and 2)). The reason is presumably as follows: This section describes the case where the side member is positioned 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). When the laminate film is welded to the side member, the heat applied to the laminate film is also absorbed by the side member and the electrode body, so not all of the applied heat contributes to the melting of the inner surface of the laminate film. Furthermore, in an electrode body where the side member is positioned biased to one side on the side of the electrode body, it is thought that there is a difference in the amount of heat absorbed by the electrode body between one side of the side member and the other side in the longitudinal direction of the side (the X direction in Figures 1 and 2). In other words, on the side of the electrode body, it is thought that the amount of heat absorbed by the electrode body when welding the laminate film will be greater on the side member closer to a wider area, and less on the side member closer to a narrower area. This is presumed to be because the volume of electrodes contributing to heat absorption on the wider region (i.e., the volume of electrodes near the side member on the wider region) is larger than the volume of electrodes contributing to heat absorption on the narrower region (i.e., the volume of electrodes near the side member on the narrower region). Consequently, in the laminate film in contact with the side member on the wider region (left side in Figures 1 and 2), the amount of heat absorbed by the electrodes is large, resulting in less heat contributing to the melting of the inner surface of the laminate film. This reduces the amount of melting, resulting in a thicker laminate film after welding. On the other hand, in the laminate film in contact with the side member on the narrower region (right side in Figures 1 and 2), the amount of heat absorbed by the electrodes is small, resulting in more heat contributing to the melting of the inner surface of the laminate film. This increases the amount of melting, resulting in a thinner laminate film after welding. Based on the above mechanism, it is presumed that differences in thickness occur in the laminate film after welding in the region in contact with the side member.

[0021] Therefore, in the manufacturing method of a laminated battery and the laminated battery according to the embodiment of this disclosure, the shape of the side members is such that the thickness increases continuously toward the side where the side members are arranged unevenly (i.e., from the wide area side toward the narrow area side (right side in Figures 1 and 2)). This reduces the volume of the side member itself on the wide area side (left side in Figures 1 and 2) and also reduces the contact surface area between the side member and the electrode body, while increasing the volume of the side member itself on the narrow area side (left side in Figures 1 and 2) and also increases the contact surface area between the side member and the electrode body. As a result, the amount of heat absorbed by the side member and the electrode body can be reduced in the laminate film in contact with the side member on the wide area side. Furthermore, the amount of heat absorbed by the side member and the electrode body can be increased in the laminate film in contact with the side member on the narrow area side. As a result, the amount of heat contributing to the melting of the inner surface of the laminate film during welding can be homogenized in the laminate film in contact with the wide-area side member and the laminate film in contact with the narrow-area side member. Furthermore, differences in thickness can be suppressed in the laminate film after welding in the area in contact with the side member.

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

[0023] (Overall configuration of vehicle 100) Figure 3 is a schematic plan view showing the main parts of a vehicle 100 to which the battery pack 10 according to the embodiment is applied. As shown in Figure 3, the vehicle 100 is a battery electric vehicle (BEV) with the battery pack 10 mounted under the floor. In each figure, the arrows UP, FR, and LH indicate the upper side in the vertical direction of the vehicle, the front side in the longitudinal direction of the vehicle, and the left side in the width direction of the vehicle, respectively. When describing the directions of front, rear, left, right, up, and down, unless otherwise specified, they refer to the front and rear in the longitudinal direction of the vehicle, the left and right in the width direction of the vehicle, and the up and down in the vertical direction of the vehicle.

[0024] In this embodiment, the vehicle 100, as an example, has a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 positioned in front of the battery pack 10. The motor 108, gearbox 110, inverter 112, and charger 114 are positioned behind the battery pack 10.

[0025] The DC current output from the battery pack 10 is voltage-adjusted by the DC / DC converter 102 and then supplied to the electric compressor 104, PTC heater 106, inverter 112, etc. Power is also supplied to the motor 108 via the inverter 112, causing the rear wheels to rotate and the vehicle 100 to move.

[0026] A charging port 116 is provided on the right side of the rear of the vehicle 100. By connecting a charging plug from an external charging device (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 the components constituting the vehicle 100 are not limited to the configuration described above. For example, it may be applied to a hybrid vehicle (HV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine. In this embodiment, the motor 108 is mounted at the rear of the vehicle and it is a rear-wheel drive vehicle, but it is not limited to this, and it may be a front-wheel drive vehicle with the motor 108 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, it may be a vehicle equipped with in-wheel motors for each wheel.

[0028] Here, the battery pack 10 is composed of multiple battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the left side of the vehicle 100. Furthermore, each battery module 11 is electrically connected.

[0029] Figure 4 is a schematic perspective view of the battery module 11. As shown in Figure 4, the battery module 11 is formed in a roughly rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is made of aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die-cast parts to both ends of an aluminum alloy extruded 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, busbars (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 longitudinal direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle vertical direction is, for example, 80 mm to 110 mm.

[0032] Figure 5 is a plan view of the battery module 11 with the top cover removed. As shown in Figure 5, multiple battery cells 20 are housed inside the battery module 11 in an arranged state. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to each other.

[0033] A flexible printed circuit board (FPC) 22 is placed on top of the battery cell 20. The flexible printed circuit board 22 is formed in a strip shape with the vehicle width direction as its longitudinal direction, and thermistors 24 are provided at both ends of the flexible printed circuit board 22. The thermistors 24 are not bonded to the battery cell 20, but are pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0034] Furthermore, one or more cushioning materials (not shown) are housed inside the battery module 11. For example, the cushioning material is a thin, elastically deformable plate-like member, and is arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 as the thickness direction. In this embodiment, as an example, cushioning material is arranged at both ends in the longitudinal direction and in the longitudinal center of the battery module 11.

[0035] Figure 6 is a schematic view of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Figure 6, the battery cell 20 is formed in a roughly rectangular plate shape, and an electrode body (not shown) is housed inside. The electrode body is composed of a positive electrode, a negative electrode, and a separator stacked together, and is sealed with a laminate film 28.

[0036] In this embodiment, as an example, the electrode housing is formed by folding and bonding an embossed sheet-like laminate film 28. While both a single-cup embossed structure with one embossed area and a double-cup embossed structure with two embossed areas can be employed, this embodiment uses a single-cup embossed structure with a fold depth of approximately 8mm to 10mm.

[0037] The upper ends of both longitudinal sides of the battery cell 20 are bent, and the corners form the outer shape. In addition, the upper end of the battery cell 20 is bent, and a fixing tape 30 is wrapped around the upper end of the battery cell 20 along its 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 a position offset below the vertical center of the battery cell 20. The terminals 26 are joined to a busbar (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, 530mm~600mm, 600mm~700mm, 700mm~800mm, 800~900mm, and 1000mm or more. The length CW2 of the area where the electrode body is housed is, for example, 500mm~520mm, 600mm~700mm, 700mm~800mm, 800~900mm, and 1000mm or more. The height CH of the battery cell 20 is, for example, 80mm~110mm and 110mm~140mm. The thickness of the battery cell 20 is 5.0mm~7.0mm, 7.0mm~9.0mm, and 9.0mm~11.0mm. The height TH of the terminal 26 is 40mm~50mm, 50mm~60mm, and 60mm~70mm. [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 Laminating film, 30 Fixing tape, 41A, 42A area, 100 Vehicle, 102 Converter, 104 Electric compressor, 106 Heater, 108 Motor, 110 Gearbox, 112 Inverter, 114 Charger, 116 Charging port

Claims

1. Electrode body and A side member arranged on the side of the electrode body, The device comprises a laminate film that covers the electrode body and a part of the side member, A method for manufacturing a laminated battery, wherein the side member is positioned in the longitudinal direction of the side at a location offset to one side with respect to the center of the side, The process includes a step of welding the laminate film so as to cover the electrode body and a portion of the side member, A method for manufacturing a laminated battery, wherein the side member has a shape in which the thickness increases continuously toward the side where the side member is positioned unevenly.

2. Electrode body and A side member arranged on the side of the electrode body, The device comprises a laminate film covering the electrode body and a portion of the side member, The side member is positioned in a location that is offset to one side with respect to the center of the side in the longitudinal direction of the side, The aforementioned side members have a shape in which the thickness increases continuously toward the side where the side members are positioned unevenly, in a laminated battery.

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