Laminate type battery

Abstract

To provide a laminate type battery that can improve the structural efficiency of a battery.SOLUTION: A laminate type battery includes a battery element, and a laminate film that covers and encapsulates the battery element. The laminate film includes a fused portion where the ends are made to overlap each other and the inner surfaces are fused, the laminate film having a fused portion side surface where the fused portion is formed, an opposite side surface facing the fused portion side surface, and a pair of main surfaces that are perpendicular to the fused portion side surface and the opposite side surface and have larger areas than the fused portion side surface and the opposite side surface, and the laminate film has an uneven shape on at least one of the fused portion side surface and the opposite side surface.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 have been studied in the past, in which battery elements such as electrodes are covered and encapsulated with a laminate film, and the ends of the laminate film are overlapped and fused together at their inner surfaces.

[0003] For example, Patent Document 1 discloses a sheet material battery in which both electrodes of a power generating element for a battery are pulled out to the outside, the power generating element for a battery is sandwiched from above and below between internal components of uneven plate material, the whole is wrapped in a sheet material, and the edges of the sheet material are hermetically joined and sealed by heat welding or the like, the uneven plate material being a one-sided uneven plate that has uneven portions on the side opposite to the side that sandwiches the power generating element for the battery, and the sheet material also has unevenness that corresponds to the unevenness of the uneven plate material, and these uneven portions are combined to form convex portions and concave portions on the upper and lower side surfaces of the sheet material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-49054 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when forming a fused portion in which the ends of the laminate film are overlapped and the inner surfaces are fused, a method is adopted in which, in order to improve sealing performance, a battery element covered with the laminate film is placed in a reduced pressure space, and the overlapped ends of the laminate film are heat-fused in a reduced pressure state to form the fused portion. However, when the laminated battery after the fused portion is formed is removed from the reduced pressure space and released from the reduced pressure state, deflection occurs on the side and opposite side of the fused portion of the laminate film, which can reduce the structural efficiency of the battery.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and has an object to provide a laminate-type battery that can improve the structural efficiency of the battery. [Means for solving the problem]

[0007] Means for solving the above problems include the following aspects. <1> A battery element; a laminate film that covers and encapsulates the battery element; The laminate film has a fused portion where the ends are overlapped and fused to each other on the inner surface, The laminate film has a fusion portion side surface on which the fusion portion is formed, an opposite side surface facing the fusion portion side surface, and a pair of main surfaces perpendicular to the fusion portion side surface and the opposite side surface and larger in area than the fusion portion side surface and the opposite side surface, The laminate film has an uneven shape on at least one of the fused portion side surface and the opposite side surface. <2> The laminate film has the uneven shape on the opposite side. <1> 2. The laminated battery according to claim 1 . <3> The laminate film has an uneven shape in which recesses and protrusions are repeated from one of the main surface side to the other main surface side on at least one of the fusion portion side surface and the opposite side surface. <1> or <2> 2. The laminated battery according to claim 1 . <4> The laminate film has the uneven shape on the entire surface of at least one of the fusion portion side surface and the opposite side surface. <1> ~ <3> 13. The laminated battery according to claim 12 . Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a laminate-type battery that can improve the structural efficiency of the battery. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a laminated battery according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a schematic cross-sectional view illustrating a conventional laminated battery. [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] <Laminated battery> A laminated battery according to an embodiment of the present disclosure includes a battery element and a laminate film that covers and encapsulates the battery element. The laminate film has a fusion part where the ends are overlapped and the inner surfaces are fused together. The laminate film has a fusion part side where the fusion part is formed, an opposite side opposite to the fusion part side, and a pair of main surfaces that are orthogonal to the fusion part side and the opposite side and have a larger area than the fusion part side and the opposite side. The laminate film has an uneven shape on at least one of the fusion part side and the opposite side.

[0011] Hereinafter, one embodiment of a laminate type battery according to an embodiment of the present disclosure will be described with reference to the drawings. The drawings shown below are schematic diagrams, and the size and shape of each part are appropriately exaggerated to make them easier to understand.

[0012] 1 is a schematic cross-sectional view illustrating a laminated battery according to an embodiment of the present disclosure, in which the upper Fig. 1(a) shows the laminated battery before it is released from the reduced pressure state when forming the fused part in the laminate film, and the lower Fig. 1(b) shows the laminated battery after it is released from the reduced pressure state when forming the fused part in the laminate film.

[0013] The laminated battery 20 shown in FIG. 1(a) has an electrode body 5 as an example of a battery element formed in a substantially rectangular plate shape, and a laminate film 28 that covers and encloses the electrode body 5. The laminated film 28 has a fusion part 28A in which the ends are overlapped and the inner surface is fused, and the inside of the laminated film 28 is sealed by the fusion part 28A. The laminated film 28 has four surfaces: a fusion part side surface 20A arranged on the side where the fusion part 28A is formed, an opposite side surface 20B facing the fusion part side surface 20A, and a pair of main surfaces 20C and 20D that are perpendicular to the fusion part side surface 20A and the opposite side surface 20B and have a larger area than the fusion part side surface 20A and the opposite side surface 20B. The main surfaces 20C and 20D are surfaces that are in the stacking direction when a battery stack is formed by stacking a plurality of laminated batteries 20. The laminate film 28 has an uneven shape 20X on the opposite side 20B.

[0014] In the laminated battery according to the embodiment of the present disclosure, the laminate film has an uneven shape on the opposite side, thereby making it possible to improve the structural efficiency of the battery.

[0015] Here, a method for forming a fused portion in a laminate film in a conventional laminate battery will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view illustrating a conventional laminate battery, in which Fig. 2(a) on the upper side shows the laminate battery before it is released from the reduced pressure state when the fused portion is formed in the laminate film, and Fig. 2(b) on the lower side shows the laminate battery after it is released from the reduced pressure state when the fused portion is formed in the laminate film. The laminated battery 200 shown in FIG. 2(a) has an electrode body 5 formed in a substantially rectangular plate shape and a laminate film 228 that covers and encapsulates the electrode body 5. The laminate film 228 has a fusion part 228A in which the ends are overlapped and the inner surface is fused. The laminate film 28 has four surfaces: a fusion part side surface 200A arranged on the side where the fusion part 228A is formed, an opposite side surface 200B facing the fusion part side surface 200A, and a pair of main surfaces 200C and 200D that are perpendicular to the fusion part side surface 200A and the opposite side surface 200B and have a larger area than the fusion part side surface 200A and the opposite side surface 200B. The laminate film 228 does not have an uneven shape on either the fusion part side surface 200A or the opposite side surface 200B.

[0016] In this laminated battery 200, when forming the fusion part 228A in the laminate film 228, first, the electrode body 5 is covered with the laminate film 228, and the ends of the laminate film 228 are overlapped. Next, the electrode body 5 and the laminate film 228 are placed in a reduced pressure space, and the overlapped ends of the laminate film 228 are heat-sealed in a reduced pressure state to form the fusion part 228A. Since the electrode body 5 generally has dimensional differences for each individual electrode body 5, the laminate film 228 is usually designed to have a size with a margin relative to the size of the electrode body 5. Therefore, by performing heat fusion on the laminate film 228 in a state in which it is placed in a reduced pressure space as described above, the sealing property between the laminate film 228 and the electrode body 5 can be improved. However, when the laminated battery 200 after the fusion portion 228A is formed is taken out of the reduced pressure space and released from the reduced pressure state, a pressure difference occurs between the inside and outside of the laminated film 228, and the laminated film 228 may bend 200X on the opposite side 200B. When the bending 200X occurs, the opposite side 200B of the laminated film 228 becomes curved as shown in FIG. 2, and as a result, the position of the end of the opposite side 200B may expand from position a to position b. When a conventional laminated battery 200 is used, it is assumed in advance that the bending 200X occurs on the opposite side 200B of the laminated film 228 and the laminated film 228 becomes curved, and the wall 210 of the battery case that houses the laminated battery 200 is designed to be located outside position b shown in FIG. 2. That is, the structural efficiency may be reduced by the occurrence of the warp 200X on the opposite side 200B of the laminate film 228, which results in a curved surface. Note that the warp in the laminate film 228 may occur not only on the opposite side 200B, but also on the fused portion side 200A.

[0017] In contrast, in the laminated battery according to the embodiment of the present disclosure, the laminate film has an uneven shape on at least one of the fused portion side and the opposite side. Therefore, even if the laminated battery after the fused portion is formed is taken out of the reduced pressure space and released from the reduced pressure state, and a pressure difference occurs between the inside and outside of the laminate film, the laminate film on the opposite side and the fused portion side is prevented from bending. In other words, the bending that would otherwise occur is absorbed by the uneven shape, making it less likely to bend. Therefore, for example, as shown in Fig. 1, the position of the end of the opposite side surface 20B after the reduced pressure state is released can be restricted to an extent that it spreads from position c to position d, compared to the conventional laminated battery shown in Fig. 2. As a result, for example, the position of the wall 210 of the battery case that houses the laminated battery 20 can be shifted in the direction of arrow S, compared to the case in which the conventional laminated battery shown in Fig. 2 is housed, and the structural efficiency of the battery can be improved.

[0018] In this way, according to the laminate type battery according to the embodiment of the present disclosure, the structural efficiency of the battery can be improved.

[0019] In FIG. 1, the laminate film 28 has an uneven shape 20X on the opposite side 20B (the surface facing the fused part side 20A), but the laminated type battery according to the embodiment of the present disclosure is not limited to this. That is, the fused part side 20A in FIG. 1 may have an uneven shape, or both the fused part side 20A and the opposite side 20B may have uneven shapes. The laminate film may also sag on the fused part side, but by having an uneven shape on the fused part side 20A, the occurrence of sagging on the fused part side is suppressed. However, in the laminated battery according to the embodiment of the present disclosure, it is preferable that at least the opposite side of the laminate film has an uneven shape from the viewpoint of making it easier to increase the structural efficiency of the battery.

[0020] 1 shows an embodiment of laminate film 28 having an uneven shape in which recesses and protrusions are repeated from one main surface 20C side to the other main surface 20D side (i.e., from top to bottom in FIG. 1), but the laminate-type battery according to the embodiment of the present disclosure is not limited to this. That is, the laminate-type battery may have an uneven shape in which recesses and protrusions are repeated in a direction perpendicular to the direction from one main surface 20C side to the other main surface 20D side (i.e., the depth direction in FIG. 1). However, from the viewpoint of making it easier to improve the structural efficiency of the battery, it is preferable for the laminated battery according to the embodiment of the present disclosure to have an uneven shape in which recesses and protrusions are repeated from one main surface 20C side to the other main surface 20D side (i.e., from top to bottom in Figure 1).

[0021] In FIG. 1, an embodiment in which the opposite side 20B has the uneven shape 20X over the entire surface thereof is shown, but the laminated battery according to the embodiment of the present disclosure is not limited thereto. That is, the uneven shape may be formed only partially on the opposite side 20B of the laminate film 28. For example, the laminate film 28 may have an uneven shape only on the area on the principal surface 20C side on the opposite side 20B, or may have an uneven shape only on the area on the other principal surface 20D side on the opposite side 20B. Also, the uneven shape may be formed only in the center area (i.e., the area on the principal surface 20C side and the area on the principal surface 20D side are not formed with uneven shapes). Furthermore, the uneven shape may be formed only partially in the direction perpendicular to the direction from one principal surface 20C side to the other principal surface 20D side (i.e., the depth direction in FIG. 1). The same applies to the case where the laminate film has an uneven shape on the side surface of the fusion part, and the uneven shape may be formed only partially on the side surface of the fusion part of the laminate film in the direction from one main surface 20C to the other main surface 20D (i.e., the vertical direction in Fig. 1). Also, the uneven shape may be formed only partially on the side surface of the fusion part of the laminate film in the direction perpendicular to the direction from one main surface 20C to the other main surface 20D (i.e., the depth direction in Fig. 1). However, in the laminated battery according to the embodiment of the present disclosure, it is preferable that the laminate film has an uneven shape over the entire surface of at least one of the fused portion side surface and the opposite side surface, from the viewpoint of making it easier to increase the structural efficiency of the battery.

[0022] In FIG. 1, an embodiment in which an uneven shape having three convex portions and three concave portions is formed on the opposite side surface 20B is shown, but the laminated battery according to the embodiment of the present disclosure is not limited thereto. The uneven shape of the laminate film on at least one of the fusion part side surface and the opposite side surface may have at least one convex portion and one concave portion. From the viewpoint of facilitating the improvement of the structural efficiency of the battery, the uneven shape formed on at least one of the fusion part side surface and the opposite side surface of the laminate film is preferably an uneven shape having three or more convex portions and three or more concave portions, more preferably an uneven shape having five or more convex portions and five or more concave portions, and even more preferably an uneven shape having ten or more convex portions and ten or more concave portions. The upper limit of the number of convex portions and concave portions is not particularly limited, but may be, for example, an uneven shape having 30 or less convex portions and 30 or less concave portions.

[0023] Next, a battery module, a battery pack, and a vehicle having a laminated battery according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the laminated battery according to the embodiment of the present disclosure is used as the battery cell shown in Figs. 5 and 6 below.

[0024] (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.

[0025] 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.

[0026] 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.

[0027] 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 device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the on-board charger 114.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, the length CW2 of the area in which the electrode body is housed is, for example, 500 mm to 520 mm, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm. The thickness of the battery cell 20 is 7.0 mm to 9.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm. [Explanation of symbols]

[0041] 5 electrode body, 20A, 200A fusion part side, 20B, 200B opposite side, 20C, 20D, 200C, 200D main surface, 20X uneven shape, 28A, 228A fusion part, 200X deflection, 210 wall of battery case, 10 battery pack, 11 battery module, 12 voltage terminal, 14 connector, 20, 200 battery cell (laminated battery), 22 flexible printed circuit board, 24 thermistor, 26 terminal, 28, 228 laminate film, 30 fixing tape, 100 vehicle, 102 converter, 104 electric compressor, 106 heater, 108 motor, 110 gear box, 112 inverter, 114 on-board charger, 114 charger, 116 charging port

Claims

1. A battery element; a laminate film that covers and encapsulates the battery element; The laminate film has a fused portion where the ends are overlapped and fused to each other on the inner surface, The laminate film has a fusion portion side surface on which the fusion portion is formed, an opposite side surface facing the fusion portion side surface, and a pair of main surfaces perpendicular to the fusion portion side surface and the opposite side surface and larger in area than the fusion portion side surface and the opposite side surface, The laminate film has an uneven shape on at least one of the fused portion side surface and the opposite side surface.

2. The laminated battery according to claim 1 , wherein the laminate film has the uneven shape on the opposite side.

3. 2. The laminated battery according to claim 1, wherein the laminate film has an uneven shape in which recesses and protrusions are repeated from one of the main surface side to the other main surface side on at least one of the fused portion side and the opposite side.

4. The laminated battery according to claim 1 , wherein the laminate film has the uneven shape over the entire surface of at least one of the fused portion side surface and the opposite side surface.

Images