Laminated batteries

Abstract

To provide a laminate type battery with a small external width.SOLUTION: A laminate type battery includes an electrode body and a laminate film that covers and encapsulates the electrode body, the laminate film includes a film main body covering four faces of the rectangular parallelepiped electrode body and two lid members respectively covering the remaining two side faces of the electrode body, the lid member has a concave shape consisting of a bottom face and four wall faces, the outer surface or inner surface of the concave shape of the bottom face faces the side faces of the electrode body, and the outer surfaces of the concave shapes of the walls is fused to the film main body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a laminated battery.

Background Art

[0002] Conventionally, laminated batteries in which an electrode body including a positive electrode, a negative electrode, and a separator is covered and enclosed by a laminate film have been studied.

[0003] For example, Patent Document 1 discloses a laminated secondary battery obtained by connecting an electrode terminal to a battery element in which positive electrode layers and negative electrode layers are alternately stacked with separators interposed therebetween, exposing the electrode terminal to the outside, and vacuum-packaging the battery element with a laminate film, wherein the separator, the positive electrode layers, and the negative electrode layers have similar shapes to each other, the areas of the separator, the positive electrode layers, and the negative electrode layers are gradually decreased in the stacking direction while maintaining the similar shapes, and the cross-sectional shape of the battery element in the stacking direction is trapezoidal.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0005] Conventionally, for reasons such as size reduction of products on which a battery is mounted, size reduction of the battery itself has been required. Therefore, even in a battery in which the electrode body is covered with a laminate film, it is desired to minimize the volume of space and the like generated due to the presence of the laminate film, and to reduce the overall size of the battery after being enclosed in the laminate film.

[0006] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a laminated battery having a small outer width. [Means for solving the problem]

[0007] The means for solving the above problems include the following embodiments. <1> It comprises an electrode body and a laminate film that covers and seals the electrode body, The laminate film comprises a film body that covers four sides of the rectangular electrode body, and two cover members that each cover the remaining two sides of the electrode body. A laminate-type battery, wherein the lid member has a concave shape composed of one bottom surface and four wall surfaces, the outer surface or inner surface of the concave shape on the bottom surface is opposite to the side surface of the electrode body, and the outer surface of the concave shape on the wall surface is fused to the film body. <2> The lid member is such that the concave outer surface on the bottom surface is opposite the side surface of the electrode body. <1> Laminated battery as described above. <3> The fused portion where the concave outer surface of the wall surface of the lid member and the film body are fused is folded inward toward the concave shape. <2> Laminated battery as described above. <4> In the fused portion where the concave outer surface of the wall surface of the lid member and the film body are fused together, the film body further wraps around to the concave inner surface of the wall surface of the lid member and covers the wall surface. <2> or <3> Laminated battery as described above. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a laminated battery with a small width in its external dimensions. [Brief explanation of the drawing]

[0009] [Figure 1] (A) is a schematic perspective view showing a laminate film in a laminate battery according to an embodiment of the present disclosure, and (B) is a schematic perspective view showing a laminate film in a laminate battery according to another embodiment of the present disclosure. [Figure 2](A) is a schematic side view showing a modified example of a laminated battery according to the embodiment of the present disclosure, and (B) is a schematic cross-sectional view showing a modified example of a laminated battery according to the embodiment of the present disclosure. [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] The following describes an example of an embodiment of this disclosure. These descriptions and examples are illustrative and do not limit the scope of the invention. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0011] <Laminated battery> The laminated battery according to the embodiment of this disclosure comprises an electrode body and a laminate film that covers and seals the electrode body. The laminate film comprises a film body that covers four sides of the rectangular electrode body, and two cover members that each cover the remaining two sides of the electrode body. The lid member has a concave shape consisting of one bottom surface and four wall surfaces, with the outer or inner concave surface of the bottom surface facing the side surface of the electrode body, and the outer surface of the wall surfaces being fused to the film body.

[0012] Batteries are required to be miniaturized themselves due to reasons such as the miniaturization of products equipped with batteries. Therefore, even for batteries in which an electrode assembly is covered with a laminate film, it is required to reduce the volume of spaces and the like generated by covering with the laminate film, that is, miniaturization of the entire battery including the laminate film is desired. Conventional laminated batteries have a configuration in which the electrode assembly is covered with, for example, only one laminate film. In this case, one laminate film is wound so as to cover four surfaces of the electrode assembly, ends of the laminate film are fused to each other, and then the remaining two side surfaces of the electrode assembly are fused by folding the excess laminate film on the side surface side to encapsulate the electrode assembly.

[0013] In contrast, the laminated battery according to the embodiment of the present disclosure is configured such that four surfaces of the electrode assembly are covered by a film body, and the remaining two side surfaces (a pair of side surfaces) of the electrode assembly are respectively covered by two lid members separate from the film body. Therefore, there is no need to fold the excess laminate film on the side surface of the electrode assembly into a shape for fusion bonding, and the length of the entire laminated battery in the width direction (the direction in which the two side surfaces of the electrode assembly face each other) can be reduced. As a result, the size of the laminated battery can be reduced, volumetric efficiency is improved, and energy density can be increased.

[0014] Next, the laminated battery according to the embodiment of the present disclosure will be described in detail with specific examples with reference to the drawings. Each of the following drawings is a schematic diagram, and the size and shape of each part are appropriately exaggerated for easy understanding.

[0015] (First aspect) FIG. 1(A) is a schematic perspective view showing a laminate film in a laminated battery according to an embodiment of the present disclosure. In FIG. 1(A), in order to facilitate understanding of the configuration of the laminate film which is a feature of the present disclosure, the electrode body is omitted, and only the laminate film (the film main body and the lid member) that covers and encloses the electrode body is shown.

[0016] The laminate film 28A shown in FIG. 1(A) includes a film main body 280 and two lid members 282. As indicated by the dotted line in FIG. 1(A), the two lid members 282 are fitted so as to enter the inner side of the film main body 280. An electrode body (not shown) is covered and enclosed by the laminate film 28A constituted by the film main body 280 and the two lid members 282.

[0017] The film main body 280 is constituted of one sheet of film. The film main body 280 is wound around the electrode body so as to cover four surfaces of the electrode body, and further, ends of the film main body 280 are fused to each other to form a main body fused portion 280A. In a state where the electrode body is covered only by the film main body 280, two side surfaces (a pair of side surfaces) of the electrode body are exposed.

[0018] Although FIG. 1(A) shows a configuration in which the film main body 280 consists of only one sheet of film, the film main body 280 may be constituted of two or more sheets of film. For example, one side ends of two sheets of film may be fused to each other, and the other ends thereof may be fused to each other, to obtain a film main body having two main body fused portions, and the film main body may be configured to be provided so as to cover four surfaces of the electrode body.

[0019] Each of the two lid members 282 has a concave shape consisting of one bottom surface 282A and four wall surfaces 282B, 282C, 282D, and 282E. The lid members 282 are fitted inside the film body 280 such that the outer surface of the concave shape on the bottom surface 282A faces the side of the electrode body (i.e., faces the internal space side of the laminate film 28A). As a result, the remaining two sides of the electrode body that are not covered by the film body 280 are covered by the bottom surface 282A of the lid member 282 (more specifically, the outer surface of the concave shape on the bottom surface 282A).

[0020] Furthermore, the lid member 282 fitted inside the film body 280 has four concave outer surfaces 282B, 282C, 282D, and 282E that are in contact with the film body 280. The concave outer surfaces of the four walls 282B, 282C, 282D, and 282E and the film body 280 in contact with each surface are fused together to form a lid fusion portion. As a result, the electrode body is sealed inside the laminate film 28A.

[0021] In a laminated battery having this configuration, the electrode body is enclosed by the laminate film 28A shown in Figure 1(A), and the overall length of the laminated battery in the width direction (the direction in which the two sides of the electrode body face each other, the Z direction in Figure 1(A)) can be shortened. As a result, the size of the laminated battery can be reduced, volumetric efficiency can be improved, and energy density can be increased.

[0022] • Modification of the first embodiment (Part 1) It is preferable that the fused portion, where the concave outer surface of the lid member's wall and the film body are fused, is folded inward toward the concave shape of the lid member.

[0023] Figure 2(A) is a schematic side view showing a modified example of a laminated battery according to the embodiment of this disclosure. Figure 2(A) is a side view of the laminated battery viewed from the width direction (the direction in which the two sides of the electrode body face each other, the Z direction in Figure 2(A)).

[0024] In the laminate film 28A-1 shown in Figure 2(A), the outer surfaces of the four wall surfaces 282B, 282C, 282D, and 282E of the lid member 282 fitted inside the film body 280 are fused to the film body 280 to form lid fused portions 286B, 286C, 286D, and 286E. These lid fused portions 286B, 286C, 286D, and 286E are then folded inward into the concave shape of the lid member 282. In the embodiment shown in Figure 2(A), the lid fused portions 286C and 286E are folded inward into the concave shape of the lid member 282 first, and then the lid fused portions 286B and 286D are folded inward into the concave shape of the lid member 282 so as to cover a part of the lid fused portions 286C and 286E from the outside.

[0025] Figure 2(A) shows a configuration in which the lid fusion portions 286C and 286E are folded inward first, followed by the lid fusion portions 286B and 286D being folded inward. However, the configuration in which the lid fusion portions are folded is not limited to this. For example, conversely to Figure 2(A), the lid fusion portions 286B and 286D may be folded inward first towards the concave shape of the lid member 282, followed by the lid fusion portions 286C and 286E being folded inward towards the concave shape of the lid member 282, covering a portion of the lid fusion portions 286B and 286D from the outside.

[0026] By integrating the fused portion, where the concave outer surface of the lid member's wall is fused to the film body, with the fused portion being folded inward towards the concave shape of the lid member, the overall length of the laminated battery in the width direction (the direction in which the two sides of the electrode body face each other, the Z direction in Figure 2(A)) can be further reduced. As a result, the size of the laminated battery can be reduced, improving volumetric efficiency and increasing energy density.

[0027] • Modification of the first embodiment (part 2) In the fused portion where the concave outer surface of the lid member's wall and the film body are fused together, it is preferable that the film body further wraps around to the concave inner surface of the lid member's wall, covering the wall surface.

[0028] Figure 2(B) is a schematic cross-sectional view showing a modified example of a laminated battery according to the embodiment of this disclosure. Figure 2(B) is a cross-sectional view of the laminated battery from a direction perpendicular to the width direction (the Y direction in Figure 2(B)).

[0029] In Figure 2(B), the battery 20 is formed by fusing the outer surfaces of the four walls (only two walls, 282B and 282D, are shown in Figure 2(B)) of the lid member 282 fitted inside the film body 280 with the film body 280, thereby forming lid fusion sections 288B and 288D. Although Figure 2(B) only shows the lid fusion section 288B where wall 282B is fused, and the lid fusion section 288D where wall 282D is fused, there are also lid fusion sections where wall 282C is fused, and lid fusion sections where wall 282E is fused. Then, in the lid fusion sections (the four lid fusion sections shown in Figure 2(B) – lid fusion sections 288B and 288D, the lid fusion section where the wall surface 282C is fused, and the lid fusion section where the wall surface 282E is fused) – the film body 280 wraps around to the concave inner surfaces of the four walls of the lid member 282 (only two walls, 282B and 282D, are shown in Figure 2(B)), forming the body wrap-around section 280C. In other words, the body wrap-around section 280C of the film body 280 covers each of the four walls of the lid member 282 up to their inner surfaces.

[0030] Figure 2(B) shows a configuration in which the wrap-around portion 280C of the film body 280 covers a portion of the inner surface of the four walls of the lid member 282. However, the configuration in which the film body wraps around and covers the four walls of the lid member is not limited to this. For example, the film body may cover the entire inner surface of the four walls of the lid member, or it may even cover the inner surface of the bottom of the lid member.

[0031] Furthermore, in a fused portion where the concave outer surface of the lid member's wall and the film body are fused together, if the film body wraps around to the concave inner surface of the lid member's wall and covers the wall, the fused portion may be further folded inward toward the concave part of the lid member.

[0032] In the fused portion where the concave outer surface of the lid member's wall and the film body are fused, the film body wraps around to the concave inner surface of the lid member's wall, covering the wall. This expands the area of ​​the fused portion between the lid member and the film body, thereby suppressing and reducing the intrusion of external air (more specifically, moisture in the air) into the internal space covered by the laminate film (i.e., the space in which the electrode body is sealed).

[0033] (Second aspect) Figure 1(B) is a schematic perspective view showing a laminate film in a laminate-type battery according to another embodiment of the present disclosure. In Figure 1(B), in order to make the structure of the laminate film, which is a feature of the present disclosure, easier to understand, the electrode bodies are omitted, and only the laminate film (film body and lid member) that covers and seals the electrode bodies is shown.

[0034] The laminate film 28B shown in Figure 1(B) has a film body 280 and two lid members 284. The two lid members 284 are fitted inside the film body 280, as shown by the dotted lines in Figure 1(B). The electrode body (not shown) is then covered and sealed by the laminate film 28B, which is composed of the film body 280 and the two lid members 284.

[0035] The film body 280 has the same configuration as shown in Figure 1(A), and therefore its explanation is omitted here.

[0036] Both lid members 284 have a concave shape consisting of one bottom surface 284A and four wall surfaces 284B, 284C, 284D, and 284E. The lid members 284 are fitted inside the film body 280 such that the inner surface of the concave shape on the bottom surface 284A faces the side of the electrode body (i.e., faces the internal space side of the laminate film 28B). As a result, the remaining two sides of the electrode body that are not covered by the film body 280 are covered by the bottom surface 284A of the lid member 284 (more specifically, the inner surface of the concave shape on the bottom surface 284A).

[0037] Furthermore, the lid member 284 fitted inside the film body 280 has four concave outer surfaces 284B, 284C, 284D, and 284E that are in contact with the film body 280. The concave outer surfaces of the four walls 284B, 284C, 284D, and 284E are fused with the film body 280 that is in contact with each surface, forming a lid fusion portion. As a result, the electrode body is sealed inside the laminate film 28B.

[0038] In a laminated battery having this configuration, the electrode body is enclosed by the laminate film 28B shown in Figure 1(B), and the overall length of the laminated battery in the width direction (the direction in which the two sides of the electrode body face each other, the Z direction in Figure 1(B)) can be shortened. As a result, the size of the laminated battery can be reduced, volumetric efficiency can be improved, and energy density can be increased.

[0039] Next, a battery module, a battery pack, and a vehicle having cell stacks according to the first and second embodiments of this disclosure will be described with reference to the figures.

[0040] (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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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]

[0057] 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, 28A, 28B Laminate film, 30 Fixing tape, 100 Vehicle, 102 Converter, 104 Electric compressor, 106 Heater, 108 Motor, 110 Gearbox, 112 Inverter, 114 Charger, 116 Charging port, 280 Film body, 282, 284 Cover members

Claims

1. It comprises an electrode body and a laminate film that covers and seals the electrode body, The laminate film comprises a film body that covers four sides of the rectangular electrode body, and two cover members that each cover the remaining two sides of the electrode body. The lid member has a concave shape composed of one bottom surface and four wall surfaces, the outer surface of the concave shape on the bottom surface is opposite to the side surface of the electrode body, and the outer surface of the concave shape on the wall surfaces is fused to the film body. The film body is bent inward toward the concave shape on the wall surface of the lid member, and at least the end of the concave shape of the lid member is covered by the film body. Laminated batteries.

2. It comprises an electrode body and a laminate film that covers and seals the electrode body, The laminate film comprises a film body that covers four sides of the rectangular electrode body, and two cover members that each cover the remaining two sides of the electrode body. The lid member has a concave shape composed of one bottom surface and four wall surfaces, the outer surface of the concave shape on the bottom surface is opposite to the side surface of the electrode body, and the outer surface of the concave shape on the wall surfaces is fused to the film body. The film body wraps around to the inner surface of the concave shape of the four wall surfaces and covers the four wall surfaces. Laminated batteries.

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