Laminated battery

Abstract

The present disclosure relates to a laminated battery having a small width in an outer shape. The laminated battery includes an electrode body and a laminated film covering and enclosing the electrode body, the laminated film includes a film main body covering four surfaces of the rectangular parallelepiped electrode body and two cover members covering the remaining two side surfaces of the electrode body, and the cover members have a concave shape formed by one bottom surface and four wall surfaces. An outer side surface or an inner side surface of the concave shape at the bottom surface opposes a side surface of the electrode body, and the outer side surface of the concave shape at the wall surface is welded to the film body.

Description

Technical Field

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

[0002] Conventionally, a laminated battery has been studied in which an electrode body including a positive electrode, a negative electrode, and a separator is covered and sealed with a laminate film.

[0003] For example, Japanese Patent Publication No. 2004-111219 discloses a laminated secondary battery, which is constructed by connecting electrode terminals to battery elements in which positive electrode layers and negative electrode layers are alternately stacked via a separator, exposing the electrode terminals to the outside and vacuum-packing the battery elements with a laminate film, wherein the separator, the positive electrode layer, and the negative electrode layer have similar shapes to each other, and the areas of the separator, the positive electrode layer, and the negative electrode layer gradually decrease in the stacking direction while maintaining similar shapes, and the cross-sectional shape of the battery element in the stacking direction is set to a trapezoidal shape.

[0004] In addition, the battery itself has been required to be miniaturized for reasons such as miniaturization of products equipped with the battery. Therefore, in a battery in which the electrode body is covered with a laminate film, it is also desired to reduce the volume of the space generated by the laminate film as much as possible and reduce the overall size after the laminate film is enclosed. Summary of the invention

[0005] The present disclosure has been made in view of the above-mentioned actual situation, and an object of the present disclosure is to provide a laminated battery having a small width in its outer shape.

[0006] Means for solving the above-mentioned problems include the following aspects.

[0007] <1> A laminated battery, comprising an electrode body and a laminated film covering and sealing the electrode body, wherein the laminated film comprises a film main body covering four sides of the rectangular parallelepiped electrode body and two cover members covering the remaining two side faces of the electrode body, respectively.

[0008] The cover member has a concave shape consisting of a bottom surface and four wall surfaces, the outer side surface or the inner side surface of the concave shape at the bottom surface faces the side surface of the electrode body, and the outer side surface of the concave shape at the wall surface is welded to the membrane body.

[0009] <2> according to <1> In the laminated battery described above, an outer side surface of the concave shape at the bottom surface of the cover member faces a side surface of the electrode body.

[0010] <3> according to <2> In the laminated battery described above, a welded portion where an outer side surface of the concave shape and the film body are welded to the wall surface of the cover member is folded toward an inner side of the concave shape.

[0011] <4> according to <2> or <3> In the described laminated battery, in the welded portion where the outer side surface of the concave shape at the wall surface of the cover member is welded to the film body, the film body further wraps around and covers the wall surface in a manner that reaches the inner side surface of the concave shape at the wall surface of the cover member.

[0012] According to the present disclosure, it is possible to provide a laminated battery having a small width in its outer shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like parts, and in which:

[0014] Figure 1A It is a schematic perspective view showing a laminate film in a laminate type battery according to an embodiment of the present disclosure.

[0015] Figure 1B This is a schematic perspective view showing a laminate film in a laminate type battery according to another embodiment of the present disclosure.

[0016] Figure 2A It is a schematic side view showing a modified example of the laminated battery according to the embodiment of the present disclosure.

[0017] Figure 2B It is a schematic cross-sectional view showing a modified example of the laminated battery according to the embodiment of the present disclosure.

[0018] Figure 3 It is a schematic plan view showing the main parts of a vehicle.

[0019] Figure 4 This is a schematic perspective view of a battery module.

[0020] Figure 5 This is a plan view of the battery module with the upper cover removed.

[0021] Figure 6 This is a schematic diagram of battery cells housed in a battery module as viewed from the thickness direction. DETAILED DESCRIPTION

[0022] Hereinafter, an embodiment as an example of the present disclosure will be described. These descriptions and examples illustrate the embodiment and do not limit the scope of the invention.

[0023] In the numerical range recorded in this specification, the upper limit or lower limit recorded in a numerical range can also be replaced by the upper limit or lower limit of other numerical ranges recorded in stages. In addition, in the numerical range recorded in this specification, the upper limit or lower limit of this numerical range can also be replaced by the value shown in the embodiment.

[0024] <Laminated battery>

[0025] A laminated battery according to an embodiment of the present disclosure includes an electrode body and a laminate film that covers and seals the electrode body.

[0026] The laminate film includes a film main body covering four surfaces of a rectangular parallelepiped electrode body and two cover members covering the remaining two side surfaces of the electrode body, respectively.

[0027] The cover member has a concave shape consisting of a bottom surface and four wall surfaces, the outer side surface or the inner side surface of the concave shape at the bottom surface faces the side surface of the electrode body, and the outer surface of the wall surface is welded to the membrane body.

[0028] For the battery, the battery itself is also required to be miniaturized for reasons such as miniaturization of products equipped with the battery. Therefore, even in a battery in which the electrode body is covered with a laminate film, it is required to reduce the volume of the space generated by covering with the laminate film, that is, the overall miniaturization including the laminate film is desired.

[0029] In addition, in conventional laminated batteries, for example, the electrode body is covered with only one laminate film. In this case, one laminate film is wound so as to cover four surfaces of the electrode body, and after the ends of the laminate film are welded to each other, the remaining two side surfaces of the electrode body are further formed into a shape in which the remaining laminate film is woven into the side surfaces and welded, thereby sealing the electrode body.

[0030] In contrast, the laminated battery of the embodiment of the present disclosure is configured to cover four surfaces of the electrode body with a membrane body, and to cover the remaining two side surfaces (a pair of side surfaces) of the electrode body with two cover members different from the membrane body. Therefore, it is not necessary to weave the remaining laminated film into the side surface of the electrode body and weld it, and 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 are opposite to each other) can be shortened. As a result, the size of the laminated battery can be reduced, the volume efficiency can be improved, and the energy density can be increased.

[0031] Next, a laminated battery according to an embodiment of the present disclosure will be described in detail with reference to specific examples using the drawings.

[0032] In addition, each figure shown below is a schematic diagram, and the size and shape of each part are exaggerated appropriately for easy understanding.

[0033] (First method)

[0034] Figure 1A 1 is a schematic perspective view showing a laminate film in a laminate type battery according to an embodiment of the present disclosure. Figure 1AIn order to facilitate understanding of the structure 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 cover member) covering and sealing the electrode body is shown.

[0035] Figure 1A The laminated film 28A shown has a film body 280 and two cover members 282. Figure 1A As shown by the middle dotted line, two cover members 282 are inserted into the inner side of the membrane main body 280. Then, the electrode body (not shown) is covered and sealed by the laminated film 28A composed of the membrane main body 280 and the two cover members 282.

[0036] The membrane body 280 is composed of a single membrane. The membrane body 280 is wound around the electrode body so as to cover the four surfaces of the electrode body, and the ends of the membrane body 280 are welded to each other to form a body welded portion 280A. When the electrode body is covered only by the membrane body 280, two side surfaces (a pair of side surfaces) of the electrode body are exposed.

[0037] In addition, Figure 1A , the membrane body 280 is shown as a structure consisting of only one membrane, but the membrane body 280 may be composed of two or more membranes. For example, the membrane body having two main body welded parts may be formed by welding one side ends of two membranes to each other and welding the other ends to each other, and the membrane body is provided in a manner covering the four surfaces of the electrode body.

[0038] Both cover members 282 have a concave shape consisting of a bottom surface 282A and four wall surfaces 282B, 282C, 282D, and 282E. In addition, the cover member 282 is embedded inside the film body 280 in such a manner that the outer side surface of the concave shape at the bottom surface 282A faces the side surface of the electrode body (i.e., faces the inner space side of the laminate film 28A). Thus, the remaining two side surfaces of the electrode body that are not covered by the film body 280 are respectively covered by the bottom surface 282A of the cover member 282 (more specifically, the outer side surface of the concave shape at the bottom surface 282A).

[0039] In addition, in the cover member 282 embedded in the inner side of the film body 280, the outer side surfaces of the concave shapes at the four walls 282B, 282C, 282D and 282E are all in contact with the film body 280. The outer side surfaces of the concave shapes at the four walls 282B, 282C, 282D and 282E and the film body 280 in contact with each surface are welded to form a cover welded portion. Thus, the electrode body is sealed inside the laminate film 28A.

[0040] In using the structure Figure 1A In the laminated battery in which the laminate film 28A shown is enclosed in the electrode body, the width direction (the direction in which the two side surfaces of the electrode body face each other, Figure 1A As a result, the size of the laminated battery can be reduced, the volume efficiency is improved, and the energy density can be increased.

[0041] ·Modification of the first aspect (Part 1)

[0042] Preferably, a welded portion where an outer side surface of the concave shape on the wall surface of the cover member and the film body are welded is folded toward an inner side of the concave shape of the cover member.

[0043] Figure 2A 1 is a schematic side view showing a modified example of a laminated battery according to an embodiment of the present disclosure. Figure 2A From the width direction (the direction in which the two sides of the electrode body face each other, Figure 2A Side view of the laminated battery observed in the Z direction).

[0044] exist Figure 2A In the laminated film 28A-1 shown, the outer side surfaces of the four walls 282B, 282C, 282D and 282E in the cover member 282 embedded in the inner side of the film body 280 are welded to the film body 280 to form cover welded parts 286B, 286C, 286D and 286E. And, the cover welded parts 286B, 286C, 286D and 286E are folded toward the inner side of the concave shape of the cover member 282. Figure 2A In the illustrated embodiment, first, the cover welding portions 286C and 286E are folded toward the inside of the concave shape of the cover member 282, and then the cover welding portions 286B and 286D are folded toward the inside of the concave shape of the cover member 282 in a manner that covers a portion of the cover welding portions 286C and 286E from the outside.

[0045] In addition, Figure 2A 286C and 286E are first folded inward, and then the cover welding parts 286B and 286D are folded inward, but the cover welding part folding method is not limited to this. Figure 2A Instead, the following method is used: first, the cover welding parts 286B and 286D are folded toward the inner side of the concave shape of the cover member 282, and then the cover welding parts 286C and 286E are folded toward the inner side of the concave shape of the cover member 282 in a manner that covers a part of the cover welding parts 286B and 286D from the outside.

[0046] By folding the welded portion where the outer side surface of the concave shape of the wall surface of the cover member and the membrane body are welded toward the inner side of the concave shape of the cover member, the width direction (the direction in which the two side surfaces of the electrode body face each other, the width of the laminated battery as a whole) can be further shortened. Figure 2AAs a result, the size of the laminated battery can be reduced, the volume efficiency is improved, and the energy density can be increased.

[0047] ·Modification of the first aspect (Part 2)

[0048] Preferably, in the welded portion where the outer side surface of the concave shape on the wall surface of the cover member and the film body are welded, the film body further wraps around the inner side surface of the concave shape on the wall surface of the cover member to cover the wall surface.

[0049] Figure 2B : is a schematic cross-sectional view showing a modified example of a laminated battery according to an embodiment of the present disclosure. Figure 2B is from the direction perpendicular to the width direction ( Figure 2B Cross-sectional view of the laminated battery observed in the Y direction).

[0050] exist Figure 2B In the battery 20 shown in the figure, in the laminated film 28A-2, four wall surfaces (in Figure 2B Only the outer side surfaces of the two wall surfaces 282B and 282D are depicted and welded to the membrane body 280 to form the cover welding parts 288B and 288D. Figure 2B Only the cover welded portion 288B welded to the wall 282B and the cover welded portion 288D welded to the wall 282D are depicted, but there are also cover welded portions welded to the wall 282C and the cover welded portions welded to the wall 282E. Figure 2B The membrane body 280 is wound around the four walls of the cover member 282 (in the four cover welding parts (cover welding parts 288B and 288D shown in FIG. 1 ), the cover welding part welded to the wall surface 282C, and the cover welding part welded to the wall surface 282E). Figure 2B Only the inner side surfaces of the concave shape at two wall surfaces 282B and 282D are depicted, forming the main body wrapping portion 280C. That is, the four wall surfaces of the cover member 282 are covered by the main body wrapping portion 280C of the membrane body 280 to the inner side surface.

[0051] In addition, Figure 2B 2 shows a method in which the main body wrapping portion 280C of the membrane main body 280 covers a part of the inner side surface of the four wall surfaces of the cover member 282, but the method in which the membrane main body wraps around and covers the four wall surfaces of the cover member is not limited to this. For example, the membrane main body may cover the entire inner side surface of the four wall surfaces of the cover member, and the membrane main body may cover the inner side surface of the bottom surface of the cover member.

[0052] In addition, in the welding portion where the outer side surface of the concave shape on the wall surface of the cover member is welded to the membrane body, the membrane body further wraps around the inner side surface of the concave shape on the wall surface of the cover member and covers the wall surface, the welding portion may be further folded toward the inner side of the concave shape of the cover member.

[0053] By configuring the membrane body to wrap around the concave inner side surface at the wall surface of the cover member and cover the wall surface in the weld portion where the concave outer side surface at the wall surface of the cover member is welded to the membrane body, the range of the weld portion between the cover member and the membrane body is widened, and the intrusion of the external atmosphere (more specifically, moisture in the atmosphere) into the internal space covered by the laminated film (i.e., the space enclosed in the electrode body) can be further suppressed.

[0054] (Second method)

[0055] Figure 1B 1 is a schematic perspective view showing a laminate film in a laminated battery according to another embodiment of the present disclosure. Figure 1B In order to facilitate understanding of the structure 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 cover member) covering and sealing the electrode body is shown.

[0056] Figure 1B The laminated film 28B shown has a film body 280 and two cover members 284. Figure 1B As shown by the middle dotted line, two cover members 284 are inserted so as to enter the inner side of the membrane body 280. Then, the electrode body (not shown) is covered and sealed by the laminated film 28B composed of the membrane body 280 and the two cover members 284.

[0057] The membrane body 280 has Figure 1A The same structures as shown are omitted here.

[0058] Both cover members 284 have a concave shape consisting of a bottom surface 284A and four wall surfaces 284B, 284C, 284D and 284E. In addition, the cover member 284 is embedded in the inner side of the film body 280 in such a manner that the inner side surface of the concave shape at the bottom surface 284A faces the side surface of the electrode body (i.e., faces the inner space side of the laminate film 28B). Thus, the remaining two side surfaces of the electrode body that are not covered by the film body 280 are respectively covered by the bottom surface 284A of the cover member 284 (more specifically, the inner side surface of the concave shape at the bottom surface 284A).

[0059] In addition, in the cover member 284 embedded in the inner side of the film body 280, the outer side surfaces of the concave shapes at the four walls 284B, 284C, 284D and 284E are all in contact with the film body 280. The outer side surfaces of the concave shapes at the four walls 284B, 284C, 284D and 284E and the film body 280 in contact with each surface are welded to form a cover welded portion. Thus, the electrode body is sealed inside the laminate film 28B.

[0060] In using the structure Figure 1B In the laminated battery in which the laminate film 28B is enclosed in the electrode body, the width direction (the direction in which the two side surfaces of the electrode body face each other, Figure 1B As a result, the size of the laminated battery can be reduced, the volume efficiency is improved, and the energy density can be increased.

[0061] Next, a battery module, a battery pack, and a vehicle including the unit stack according to the first and second embodiments of the present disclosure will be described using the drawings.

[0062] (Overall Structure of Vehicle 100)

[0063] Figure 3 1 is a schematic plan view showing the main parts of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. Figure 3 As shown, the vehicle 100 is an electric vehicle (BEV) equipped with a battery pack 10 under the floor. In addition, the arrow UP, arrow FR, and arrow LH in each figure respectively indicate the upper side in the vehicle vertical direction, the front side in the vehicle front-rear direction, and the left side in the vehicle width direction. When the front-rear, left-right, up-down directions are used for description, unless otherwise specified, they indicate the front-rear direction in the vehicle front-rear direction, the left-right direction in the vehicle width direction, and the up-down direction in the vehicle vertical direction.

[0064] As an example, the vehicle 100 of the present embodiment is provided with a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 at a position closer to the front side of the vehicle than the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are provided at a position closer to the rear side of the vehicle than the battery pack 10.

[0065] The DC current output from battery pack 10 is regulated in voltage by DC / DC converter 102 and then supplied to electric compressor 104, PTC heater 106, inverter 112, etc. In addition, by supplying power to motor 108 via inverter 112, rear wheels rotate and vehicle 100 travels.

[0066] A charging port 116 is provided on the right side of the rear portion of the vehicle 100 . By connecting a charging plug of an external charging device (not shown) to the charging port 116 , electric power can be stored in the battery pack 10 via the charger 114 .

[0067] In addition, the configuration and structure of each component constituting the vehicle 100 are not limited to the above-mentioned structure. The present disclosure can also be applied to a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine, for example. In addition, in the present embodiment, a rear-wheel drive vehicle is provided in which the motor 108 is mounted at the rear of the vehicle, but it is not limited to this. It can also be provided as a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 can be mounted at the front and rear of the vehicle. Moreover, it can also be a vehicle in which each wheel has an in-wheel motor.

[0068] Here, the battery pack 10 is configured to include a plurality of battery modules 11. In the present embodiment, as an example, 10 battery modules 11 are provided. Specifically, five battery modules 11 are arranged along the vehicle front-rear direction on the right side of the vehicle 100, and five battery modules 11 are arranged along the vehicle front-rear direction on the left side of the vehicle 100. In addition, each battery module 11 is electrically connected.

[0069] Figure 4 1 is a schematic three-dimensional diagram of the battery module 11. Figure 4 As shown, the battery module 11 is formed into a substantially rectangular parallelepiped shape with the vehicle width direction as the length direction. In addition, the outer shell of the battery module 11 is formed of an aluminum alloy. For example, an aluminum die casting is joined to both ends of an aluminum alloy extrusion by laser welding or the like, thereby forming the outer shell of the battery module 11.

[0070] 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 described later is connected to the connector 14. Bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0071] The battery module 11 has a length MW in the vehicle width direction of, for example, 350 mm to 600 mm, a length ML in the vehicle front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the vehicle vertical direction of, for example, 80 mm to 110 mm.

[0072] Figure 5 FIG. 1 is a plan view of the battery module 11 after the upper cover is removed. Figure 5As shown, a plurality of battery cells 20 are housed in a state where the plurality of battery cells 20 are arranged in the battery module 11. In the present embodiment, as an example, 24 battery cells 20 are arranged in the vehicle front-rear direction and bonded to each other.

[0073] A flexible printed circuit (FPC) 22 is disposed on the battery cell 20. The flexible printed circuit 22 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and thermistors 24 are provided at both ends of the flexible printed circuit 22. The thermistor 24 is not bonded to the battery cell 20, but is configured to be pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0074] In addition, one or more buffers (not shown) are accommodated inside the battery module 11. For example, the buffer is a thin plate-shaped member that can be elastically deformed, 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, buffers are arranged at both ends of the battery module 11 in the longitudinal direction and in the middle of the longitudinal direction.

[0075] Figure 6 2 is a schematic diagram of a battery cell 20 housed in a battery module 11 as viewed from the thickness direction. Figure 6 As shown, the battery cell 20 is formed in a substantially rectangular plate shape, and an electrode body (not shown) is housed therein. The electrode body is composed of a positive electrode, a negative electrode, and a separator stacked together, and is sealed by a laminate film 28 .

[0076] In this embodiment, as an example, the electrode body receiving portion is formed by folding and laminating the embossed sheet-shaped laminate film 28. In addition, two structures, a single cup embossed structure with embossing at one place and a double cup embossed structure with embossing at two places, can be adopted, but in this embodiment, a single cup embossed structure with a drawing depth of about 8 mm to 10 mm is used.

[0077] The upper ends of both ends of the battery cell 20 in the longitudinal direction are bent, and the corners become the outer shape. In addition, the upper end of the battery cell 20 is bent, and the fixing band 30 is wound around the upper end of the battery cell 20 along the longitudinal direction.

[0078] Here, terminals (tabs) 26 are provided at both ends in the longitudinal direction of the battery cell 20. In the present 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 bus bars (not shown) by laser welding or the like.

[0079] 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 mm to 900 mm, or 1000 mm or more, the length CW2 of the region where the electrode body is housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm to 900 mm, or 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. In addition, the thickness of the battery cell 20 is 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, or 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, or 60 mm to 70 mm.

Claims

1. A laminated battery, wherein: The laminated battery comprises an electrode body and a laminate film covering and sealing the electrode body. The laminate film includes a film body covering four sides of the rectangular parallelepiped electrode body and two cover members covering the remaining two side faces of the electrode body, respectively. The cover member has a concave shape consisting of a bottom surface and four wall surfaces, the outer side surface or the inner side surface of the concave shape at the bottom surface faces the side surface of the electrode body, and the outer side surface of the concave shape at the wall surface is welded to the membrane body.

2. The laminated battery according to claim 1, wherein An outer side surface of the concave shape at the bottom surface of the cover member faces a side surface of the electrode body.

3. The laminated battery according to claim 2, wherein: A welded portion where an outer side surface of the concave shape on the wall surface of the cover member and the film body are welded is folded toward an inner side of the concave shape.

4. The laminated battery according to claim 2 or 3, wherein: In the welded portion where the outer side surface of the concave shape at the wall surface of the cover member and the film body are welded, the film body further wraps around and covers the wall surface so as to reach the inner side surface of the concave shape at the wall surface of the cover member.

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