Laminate type battery

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 laminate-type battery. [Background technology]

[0002] 2. Description of the Related Art Laminated batteries in which an electrode assembly having a positive electrode, a negative electrode, and a separator is covered and sealed with a laminate film have been studied.

[0003] For example, Patent Document 1 discloses a laminated secondary battery in which electrode terminals are connected to a battery element in which positive electrode layers and negative electrode layers are alternately stacked via a separator, the electrode terminals are exposed to the outside, and the battery element is vacuum-packed in a laminate film, in which the separator, positive electrode layer, and negative electrode layer have similar shapes, the areas of the separator, positive electrode layer, and negative electrode layer are gradually reduced 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 documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-111219 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, there has been a demand for miniaturization of the battery itself due to the need to miniaturize products that incorporate the battery, etc. Therefore, even in a battery in which the electrode body is covered with a laminate film, it is desirable to minimize the volume of the space, etc., that is generated by the presence of the laminate film, and to reduce the overall size after the battery is enclosed in the laminate film.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and has an object to provide a laminate-type battery having a small external width. [Means for solving the problem]

[0007] Means for solving the above problems include the following aspects. <1> The electrode assembly includes a laminate film that covers and encapsulates the electrode assembly. The laminate film has a film body that covers four sides of the rectangular parallelepiped electrode body, and two cover members that cover the remaining two side surfaces of the electrode body, A laminated battery, wherein the cover member has a concave shape consisting of one bottom surface and four wall surfaces, the outer surface or the inner surface of the concave shape of the bottom surface faces the side surface of the electrode body, and the outer surface of the concave shape of the wall surfaces is fused to the film body. <2> The cover member has an outer surface of the concave shape at the bottom surface facing a side surface of the electrode body. <1> 2. The laminated battery according to claim 1 . <3> a fusion portion at which an outer surface of the concave shape in the wall surface of the cover member and the film main body are fused to each other is folded toward the inside of the concave shape; <2> 2. The laminated battery according to claim 1 . <4> At a fusion portion where an outer surface of the concave shape in the wall surface of the lid member and the film main body are fused to each other, the film main body further wraps around to an inner surface of the concave shape in the wall surface of the lid member to cover the wall surface. <2> or <3> 2. The laminated battery according to claim 1 . Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a laminate-type battery having a small external width. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2A is a schematic perspective view showing a laminate film in a laminate battery according to an embodiment of the present disclosure, and FIG. 2B is a schematic perspective view showing a laminate film in a laminate battery according to another embodiment of the present disclosure. [Diagram 2]FIG. 2A is a schematic side view showing a modified example of a laminated battery according to an embodiment of the present disclosure, and FIG. 2B is a schematic cross-sectional view showing a modified example of 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] 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] Hereinafter, an embodiment that is an example of the present disclosure will be described. These descriptions and examples are merely illustrative of the embodiment, and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0011] <Laminated battery> A laminate type battery according to an embodiment of the present disclosure has an electrode assembly and a laminate film that covers and encapsulates the electrode assembly. The laminate film has a film body that covers the four faces of a rectangular parallelepiped electrode body, and two cover members that respectively cover the remaining two side faces of the electrode body. The cover member has a concave shape consisting of a bottom surface and four wall surfaces, with the outer surface or inner surface of the concave shape of the bottom surface facing the side surface of the electrode body, and the outer surfaces of the walls being fused to the film body.

[0012] There is a demand for batteries to be miniaturized in order to reduce the size of the products in which the batteries are mounted, etc. Therefore, even in batteries in which the electrode body is covered with a laminate film, there is a demand to reduce the volume of the space, etc., that is, there is a demand for miniaturization of the entire battery, including the laminate film. In a conventional laminated battery, for example, the electrode body is covered with only one laminate film. In this case, one laminate film is wrapped around the four sides of the electrode body to cover them, and the ends of the laminate film are fused together. Then, the remaining two side surfaces of the electrode body are fused in a shape in which the excess laminate film on the side surfaces is woven in, thereby encapsulating the electrode body.

[0013] In contrast, the laminated battery according to the embodiment of the present disclosure has a structure in which the four faces of the electrode body are covered by the film body, and the remaining two side faces (a pair of side faces) of the electrode body are covered by two lid members separate from the film body. Therefore, it is not necessary to weave the surplus laminated film on the side faces of the electrode body and fuse it, and the length of the laminated battery as a whole in the width direction (the direction in which the two side faces of the electrode body face each other) can be shortened. As a result, the size of the laminated battery can be reduced, the volumetric efficiency can be improved, and the energy density can be increased.

[0014] Next, a laminated battery according to an embodiment of the present disclosure will be described in detail with reference to the drawings and specific examples. It should be noted that the drawings shown below are schematic diagrams, and the size and shape of each part are appropriately exaggerated to facilitate 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 easily understand the configuration of the laminate film, which is a feature of the present disclosure, the electrode body is omitted and only the laminate film (film body and lid member) that covers and encapsulates the electrode body is shown.

[0016] Laminate film 28A shown in Fig. 1(A) has a film main body 280 and two lid members 282. As shown by dotted lines in Fig. 1(A), the two lid members 282 are fitted into the inside of film main body 280. Then, laminate film 28A composed of film main body 280 and two lid members 282 covers and encapsulates an electrode body (not shown).

[0017] The film body 280 is composed of a single film. The film body 280 is wrapped around the electrode body so as to cover the four faces of the electrode body, and ends of the film body 280 are fused together to form a fused body part 280A. When the electrode body is covered only by the film body 280, two side faces (a pair of side faces) of the electrode body are exposed.

[0018] 1(A) shows a configuration in which the film body 280 is made of only one film, but the film body 280 may be made of two or more films. For example, one side end of two films may be fused together and the other ends may be fused together to form a film body having two fused body parts, and this film body may be provided so as to cover the four surfaces of the electrode body.

[0019] Each of the two lid members 282 has a concave shape composed of one bottom surface 282A and four wall surfaces 282B, 282C, 282D, and 282E. The lid member 282 is fitted inside the film main body 280 so that the outer surface of the concave shape of 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 side surfaces of the electrode body that are not covered by the film main body 280 are covered by the bottom surface 282A of the lid member 282 (more specifically, the outer surface of the concave shape of the bottom surface 282A).

[0020] In addition, the concave outer surfaces of the four wall surfaces 282B, 282C, 282D, and 282E of the lid member 282 fitted inside the film main body 280 are all in contact with the film main body 280. The concave outer surfaces of the four wall surfaces 282B, 282C, 282D, and 282E and the film main body 280 in contact with each surface are fused to form a lid fusion portion. As a result, the electrode body is enclosed inside the laminate film 28A.

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

[0022] Modification of the first aspect (part 1) It is preferable that the fused portion where the outer side surface of the concave shape of the wall surface of the lid member and the film main body are fused is folded towards the inside of the concave shape of the lid member.

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

[0024] In the laminate film 28A-1 shown in Fig. 2(A), the outer surfaces of the four walls 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 the lid fusion parts 286B, 286C, 286D, and 286E. The lid fusion parts 286B, 286C, 286D, and 286E are folded toward the inside of the concave shape of the lid member 282, respectively. In the embodiment shown in Fig. 2(A), the lid fusion parts 286C and 286E are first folded toward the inside of the concave shape of the lid member 282, and then the lid fusion parts 286B and 286D are folded toward the inside of the concave shape of the lid member 282 so as to cover a part of the lid fusion parts 286C and 286E from the outside.

[0025] 2(A) shows a state in which the lid fusion parts 286C and 286E are folded inward first, and then the lid fusion parts 286B and 286D are folded inward, but the manner in which the lid fusion parts are folded is not limited to this. For example, contrary to FIG. 2(A), the lid fusion parts 286B and 286D may be folded inward in the concave shape of the lid member 282, and then the lid fusion parts 286C and 286E may be folded inward in the concave shape of the lid member 282 so as to cover a part of the lid fusion parts 286B and 286D from the outside.

[0026] By configuring the fusion portion where the concave outer side surface of the wall surface of the lid member and the film main body are fused to each other in the concave shape of the lid member, the length of the laminated battery as a whole in the width direction (the direction in which the two side surfaces of the electrode body face each other, the Z direction in FIG. 2(A)) can be further shortened. As a result, the size of the laminated battery can be reduced, the volumetric efficiency can be improved, and the energy density can be increased.

[0027] Modification of the first aspect (part 2) It is preferable that at the fusion portion where the film main body and the outer surface of the concave shape of the wall surface of the lid member are fused together, the film main body further extends around to cover the inner surface of the concave shape of the wall surface of the lid member.

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

[0029] In the battery 20 shown in Fig. 2(B), in the laminate film 28A-2, the outer surfaces of the four walls (only two walls 282B and 282D are shown in Fig. 2(B)) of the lid member 282 fitted inside the film body 280 are fused to the film body 280 to form lid fusion parts 288B and 288D. Note that, although Fig. 2(B) shows only the lid fusion part 288B to which the wall 282B is fused, and the lid fusion part 288D to which the wall 282D is fused, there are also a lid fusion part to which the wall 282C is fused, and a lid fusion part to which the wall 282E is fused. In the lid fusion portion (four lid fusion portions: lid fusion portions 288B and 288D shown in FIG. 2(B), the lid fusion portion to which wall surface 282C is fused, and the lid fusion portion to which wall surface 282E is fused), the film body 280 wraps around to the inner surfaces of the concave shape of the four walls of the lid member 282 (only two walls 282B and 282D are shown in FIG. 2(B)) to form a body wraparound portion 280C. In other words, the four walls of the lid member 282 are covered up to their inner surfaces by the body wraparound portion 280C of the film body 280.

[0030] 2(B) shows an aspect in which the body wraparound portion 280C of the film body 280 covers part of the inner surfaces of the four walls of the lid member 282, but the aspect 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 surfaces of the four walls of the lid member, and the film body may also cover the inner surface of the bottom surface of the lid member.

[0031] In addition, in the fused portion where the outer surface of the concave shape in the wall of the lid member and the film main body are fused, the film main body may further wrap around to the inner surface of the concave shape in the wall of the lid member to cover the wall, and the fused portion may further be folded toward the inside of the concave shape of the lid member.

[0032] At the fused portion where the concave outer surface of the wall of the lid member is fused to the film main body, the film main body wraps around to the concave inner surface of the wall of the lid member to cover the wall, thereby widening the area of ​​the fused portion between the lid member and the film main body and suppressing or reducing the intrusion of outside atmosphere (more specifically, moisture in the atmosphere) into the internal space covered by the laminate film (i.e., the space that encloses the electrode body).

[0033] (Second aspect) Fig. 1(B) is a schematic perspective view showing a laminate film in a laminated battery according to another embodiment of the present disclosure. In Fig. 1(B), in order to easily understand the configuration of the laminate film, which is a feature of the present disclosure, the electrode body is omitted and only the laminate film (film body and lid member) that covers and encapsulates the electrode body is shown.

[0034] Laminate film 28B shown in Fig. 1(B) has a film main body 280 and two lid members 284. As shown by dotted lines in Fig. 1(B), the two lid members 284 are fitted into the inside of film main body 280. Then, laminate film 28B composed of film main body 280 and two lid members 284 covers and encapsulates an electrode body (not shown).

[0035] The film body 280 has the same configuration as that shown in FIG. 1(A), and therefore a description thereof will be omitted here.

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

[0037] In addition, the concave outer surfaces of the four wall surfaces 284B, 284C, 284D, and 284E of the lid member 284 fitted inside the film main body 280 are all in contact with the film main body 280. The concave outer surfaces of the four wall surfaces 284B, 284C, 284D, and 284E are fused to the film main body 280 in contact with each surface to form a fused lid portion. This causes the electrode body to be enclosed inside the laminate film 28B.

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

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

[0040] (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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[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, bus bars (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 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[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 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.

[0056] 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]

[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 gear box, 112 inverter, 114 charger, 116 charging port, 280 film body, 282, 284 cover member

Claims

1. The electrode assembly includes a laminate film that covers and encapsulates the electrode assembly. The laminate film has a film body that covers four sides of the rectangular parallelepiped electrode body, and two cover members that cover the remaining two side surfaces of the electrode body, A laminated battery, wherein the cover member has a concave shape consisting of one bottom surface and four wall surfaces, the outer surface or the inner surface of the concave shape of the bottom surface faces the side surface of the electrode body, and the outer surface of the concave shape of the wall surfaces is fused to the film body.

2. The laminate type battery according to claim 1 , wherein the concave outer surface of the bottom surface of the lid member faces a side surface of the electrode body.

3. 3. The laminated battery according to claim 2, wherein a fused portion at which an outer side surface of the concave shape in the wall surface of the lid member and the film body are fused is folded toward the inside of the concave shape.

4. 4. The laminated battery according to claim 2, wherein at a fused portion where the outer surface of the concave shape in the wall surface of the lid member and the film body are fused, the film body further extends around to the inner surface of the concave shape in the wall surface of the lid member to cover the wall surface.

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