Battery cell and battery module

Abstract

The utility model provides a battery unit and a battery module, which can optimize the configuration of a laminated film for sealing an electrode body and realize the miniaturization of a packaging body. The battery cell is configured by laminating a plurality of electrode bodies constituting a positive electrode and a negative electrode with a film portion formed of a laminated film therebetween, joining the outer peripheral portions of the plurality of laminated film portions to each other, and integrally sealing the plurality of electrode bodies.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of battery unit and battery module. BACKGROUND

[0002] In the following patent document 1, it is described that a battery pack is configured by electrically connecting a plurality of battery units which are stacked with each other. In the battery pack described in patent document 1, each battery unit is configured by sealing a positive electrode and an electrode body (a battery element) constituting a negative electrode with an outer packaging film. That is, in a state where a plurality of battery units are stacked, insulation between electrode bodies is ensured by the outer packaging film.

[0003] Patent document 1: Japanese Patent No. 5197001

[0004] However, from the viewpoint of ensuring insulation between electrode bodies, it is sufficient to dispose one outer packaging film between electrode bodies. However, as described in patent document 1, when a single electrode body is individually externally packaged, two outer packaging films are disposed between electrode bodies adjacent in the stacking direction in a state where a plurality of battery units are stacked. Thus, when a plurality of battery units are combined into a battery pack (a battery module), the excess outer packaging film increases the thickness of the module, resulting in a large size of the package. SUMMARY

[0005] The utility model takes the above fact into consideration, and aims to provide a battery unit and a battery module that can optimize the disposition of a stacking film that seals electrode bodies and achieve a small size of a package.

[0006] The battery unit of the first aspect is configured by stacking a plurality of electrode bodies constituting a positive electrode and a negative electrode with a film portion formed by a stacking film, joining outer peripheral portions of the plurality of stacked film portions to each other, and sealing the plurality of electrode bodies integrally.

[0007] In the battery unit of the first aspect, the plurality of electrode bodies constituting a positive electrode and a negative electrode are stacked with a film portion formed by a stacking film, and thus one film portion is disposed between electrode bodies adjacent in the stacking direction. In addition, the battery unit is configured by joining outer peripheral portions of the plurality of stacked film portions to each other and sealing the plurality of electrode bodies integrally. Thus, since electrode bodies adjacent in the stacking direction are divided by one film portion, the number of stacking films disposed between electrode bodies can be reduced. As a result, the disposition of the stacking film that seals electrode bodies is optimized, and a small size of a package can be achieved.

[0008] The battery unit of the second aspect is configured by alternately stacking a plurality of embossed film portions constituted by embossed surfaces that form accommodation portions of the electrode bodies and planar film portions having a planar shape in the battery unit of the first aspect.

[0009] In the battery cell of the second aspect, the plurality of film portions are formed by alternately stacking embossed film portions formed of embossed surfaces of the housing portions of the electrode bodies and planar film portions having a planar shape. Thus, the housing of the battery cell can be in a stacked state similar to that of a battery cell having a single-cup embossed structure, and can be combined with other battery cells having a single-cup embossed structure. As a result, the versatility of the battery cell can be improved.

[0010] The battery cell of the third aspect is the battery cell of the first or second aspect, wherein the plurality of film portions are formed by one stacked film folded in a corrugated shape.

[0011] In the battery cell of the third aspect, the plurality of film portions are formed by one stacked film folded in a corrugated shape. Thus, it is not necessary to pre-cut each film portion into a film shape, and the occurrence of defects such as positional displacement or slackening during pre-cutting can be reduced. As a result, the yield of the stacked film can be improved, and the productivity of the battery cell can be improved.

[0012] The battery cell of the fourth aspect is the battery cell of the third aspect, wherein the electrode body is connected to an electrode lead protruding in the first width direction at at least one end portion in the first width direction, and the plurality of film portions are provided with the folded-back position of the corrugated folding at one and the other of a second width direction orthogonal to the first width direction.

[0013] In the battery cell of the fourth aspect, the electrode body is connected to an electrode lead protruding in the first width direction at at least one end portion in the first width direction. In addition, the plurality of film portions are provided with the folded-back position of the corrugated folding at one and the other of a second width direction orthogonal to the first width direction. Thus, in the battery cell, the folded-back position of the corrugated folding is provided at the other edge orthogonal to the leading edge of the electrode lead in the peripheral portion of the battery cell. As a result, the electrode lead does not interfere with the folded-back position of the stacked film, and thus the sealing process of the electrode body becomes easy, and the productivity of the battery cell is improved.

[0014] The battery module of the fifth aspect is a battery module in which a plurality of the battery cells of the first or second aspect are stacked with each other and housed in a module housing, and the plurality of battery cells are electrically connected to each other.

[0015] In the battery module of the fifth aspect, since the electrode bodies adjacent to each other are divided by one film portion, the arrangement of the stacked film sealing the electrode bodies can be optimized, and the package of each battery cell can be downsized. As a result, the volume of the state in which a plurality of battery cells are stacked in the module housing can be reduced, and the package of the battery module can be downsized.

[0016] As described above, in the battery cell and the battery module of the present application, the arrangement of the stacked film sealing the electrode bodies can be optimized, and the package can be downsized. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 This is a top view schematic diagram showing the main parts of a vehicle that uses the battery pack described in the embodiment.

[0018] Figure 2 This is a perspective view of the battery module involved in the implementation method.

[0019] Figure 3 The battery module involved in the implementation method is shown in a top view with the top cover of the module housing removed.

[0020] Figure 4 This is a schematic diagram showing the battery cells housed in the battery module from the thickness direction.

[0021] Figure 5A To be along Figure 4 The image shows a partially enlarged cross-sectional view of the battery cell, indicating that the AA line has been cut off.

[0022] Figure 5B To be along Figure 4 The image shows a partially enlarged cross-sectional view of the battery cell, indicating that the BB line is cut off.

[0023] Figure 6 This diagram illustrates the unfolded state of a stacked membrane comprising multiple membrane sections. Detailed Implementation

[0024] The following is for reference Figures 1-6 One embodiment of this utility model will be described.

[0025] Figure 1 This is a top view schematic diagram showing the main parts of a vehicle 100 that utilizes the battery pack 10 described in the embodiment. Figure 1 As shown, vehicle 100 is an electric vehicle (BEV) with a battery pack 10 mounted under the floor. Additionally, the arrows UP, FR, and LH in each figure represent the upper side in the vertical direction, the front side in the longitudinal direction, and the left side in the width direction, respectively. When using the directions front-back, left-right, up-down, or forward, unless otherwise specified, they represent the front-back direction, the left-right direction, and the up-down direction, respectively.

[0026] In the vehicle 100 of this embodiment, as an example, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are arranged on the side of the battery pack 10 closer to the front of the vehicle. In addition, a motor 108, a gearbox 110, an inverter 112, and a charger 114 are arranged on the side of the battery pack 10 closer to the rear of the vehicle.

[0027] The DC current output from the battery pack 10 is regulated by the DC / DC converter 102 and then supplied to the electric compressor 104, PTC heater 106, inverter 112, etc. In addition, by supplying power to the motor 108 via the inverter 112, the rear wheels rotate, thus driving the vehicle 100.

[0028] A charging port 116 is provided on the right side of the rear of the vehicle 100. By connecting the charging port 116 to the charging plug of an external charging device (not shown), the battery pack 10 can be charged via the on-board charger 114.

[0029] Furthermore, the configuration and structure of the components constituting the vehicle 100 are not limited to the above-described configuration. For example, it can also be applied to hybrid vehicles (HV) or plug-in hybrid electric vehicles (PHEV). In this embodiment, the vehicle is a rear-wheel drive vehicle with the motor 108 mounted at the rear of the vehicle; however, it is not limited to this. It could also be a front-wheel drive vehicle with the motor 108 mounted at the front of the vehicle, or a pair of motors 108 could be mounted at both the front and rear of the vehicle. Additionally, it could be a vehicle with an in-wheel motor at each wheel.

[0030] Here, the battery pack 10 includes a plurality of battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, the right side of the vehicle 100 has 5 battery modules 11 arranged in the front-rear direction, and the left side of the vehicle 100 has 5 battery modules 11 arranged in the front-rear direction. In addition, the individual battery modules 11 are electrically connected.

[0031] Figure 2 This is a three-dimensional schematic diagram of battery module 11. Figure 2 As shown, the battery module 11 has a module housing 16 that forms the outer casing. The module housing 16 is formed into a generally rectangular parallelepiped shape with the vehicle width direction as its length direction. Furthermore, the module housing 16 is formed of aluminum alloy. For example, the module housing 16 is formed by joining aluminum die-castings at both ends of extruded aluminum alloy material using laser welding or the like.

[0032] A pair of voltage terminals 12 and connectors 14 are respectively provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, described later, is connected to the connector 14. In addition, busbars (not shown) are soldered to both ends of the battery module 11 in the vehicle width direction.

[0033] The length MW of the battery module 11 in the vehicle width direction is, for example, 350mm to 600mm, the length ML in the vehicle front-to-rear direction is, for example, 150mm to 250mm, and the height MH in the vehicle vertical direction is, for example, 80mm to 110mm.

[0034] Figure 3 This is a top view showing the battery module 11 with its top cover removed. (See attached image.) Figure 3 As shown, a plurality of battery cells 20 are stacked together inside the module housing 16. Each battery cell 20 is housed in an orientation in which the stacking direction is the thickness direction. In this embodiment, a stacked body is formed by arranging (stacking) 24 battery cells 20 in the front-rear direction of the vehicle and bonding them together.

[0035] In addition, for ease of understanding, in Figures 3-5B In the various figures, the direction indicated by arrow W is defined as the width direction of battery cell 20, the direction indicated by arrow H is defined as the height direction (vertical direction) of battery cell 20, and the direction indicated by arrow D is defined as the thickness direction of battery cell 20. Furthermore, the width direction W is an example of the "first width direction," and the height direction H, which is orthogonal to the width direction W, is an example of the "second width direction."

[0036] The width direction of the outer casing material 22, described later, is consistent with the width direction W of the battery cell 20. The height direction of the outer casing material 22 is consistent with the height direction H of the battery cell 20. The thickness direction of the outer casing material 22 is consistent with the thickness direction D of the battery cell 20.

[0037] A flexible printed circuit (FPC) 21 is disposed on the battery cell 20. The flexible printed circuit 21 is formed into a strip with the width of the vehicle as its length direction, and thermistors 23 are respectively disposed at both ends of the flexible printed circuit 21. Thermistors 23 are not attached to the battery cell 20, but are formed by pressing the top cover of the battery module 11 toward the battery cell 20.

[0038] Additionally, one or more cushioning materials (not shown) are housed inside the module housing 16. For example, the cushioning material is a thin, elastically deformable plate-like component disposed between adjacent battery cells 20 whose thickness direction is the arrangement direction of the battery cells 20. In this embodiment, as an example, cushioning material is disposed at both ends and the central portion of the module housing 16 along its length.

[0039] Figure 4 This is a schematic diagram of the battery cell 20 housed in the battery module 11, viewed from the thickness direction D. Figure 4As shown, the battery cell 20 is formed as a rectangular plate with a length along the width direction W, and has multiple electrode bodies 40 and an outer casing material 22 that integrally seals the multiple electrode bodies 40. The electrode body 40 is formed into a rectangular plate by stacking a positive electrode, a negative electrode, and a separator. The electrode body 40 is connected to electrode leads 26 protruding in the width direction W at one end and the other end in the width direction W. The electrode leads 26 have a first electrode lead 26A connected to the positive electrode of the electrode body 40 in the width direction W and a second electrode lead 26B connected to the negative electrode of the electrode body 40 in the other width direction W.

[0040] The outer casing material 22 is composed of a corrugated laminated film that seals the electrode body 40. A first electrode lead 26A and a second electrode lead 26B, which are connected to the electrode body 40, are led out from one end of the outer casing material 22 in the width direction W and the other end.

[0041] As an example, the laminated film has a three-layer structure consisting of an inner layer with heat-sealing properties, an intermediate layer made of metal foil film, and an outer layer that functions as a protective layer.

[0042] Figure 5A It roughly indicates along Figure 4 A partially enlarged cross-sectional view of battery cell 20 with the AA line cut off. Figure 5B It roughly indicates along Figure 4 A partially enlarged cross-sectional view of battery cell 20 with the BB line cut off.

[0043] like Figure 5A and Figure 5B As shown, each battery cell 20 is formed by stacking multiple electrode bodies 40 that constitute the positive and negative electrodes, with a film portion 50 formed by a laminated film in between. In addition, the battery cell 20 is constructed by sealing the multiple electrode bodies 40 integrally by joining the outer peripheries of the multiple laminated film portions 50 together.

[0044] In this embodiment, the plurality of electrode bodies 40 include a first electrode body 40A and a second electrode body 40B. Additionally, the plurality of membrane portions 50 include a first membrane portion 51, a second membrane portion 52, and a third membrane portion 53.

[0045] The first film portion 51 is disposed between the first electrode body 40A and the second electrode body 40B. The first film portion 51 constitutes a planar film portion in a planar shape. The second film portion 52 overlaps the first film portion 51 from the outside of the first electrode body 40A. The second film portion 52 is an embossed film portion constituted by an embossed surface, and has a concave first housing portion 52P recessed in one of the stacking direction (thickness direction D) by embossing. The first electrode body 40A is housed in the first housing portion 52P. The third film portion 53 overlaps the first film portion 51 from the outside of the second electrode body 40B. The third film portion 53 is an embossed film portion constituted by an embossed surface, and has a concave second housing portion 53P recessed in the other of the stacking direction (thickness direction D) by embossing. The second electrode body 40B is housed in the second housing portion 53P.

[0046] In the battery cell 20, the second film portion 52, the first electrode body 40A, the first film portion 51, the second electrode body 40B, and the third film portion 53 are stacked in this order. That is, the plurality of film portions 50 of the exterior material 22 are alternately stacked by embossed film portions constituted by embossed surfaces and planar film portions in a planar shape.

[0047] On the outer peripheral portions of the second film portion 52, the first film portion 51, and the third film portion 53, a seal portion 221 is formed in the entire circumferential range, which joins the outer peripheral portions to each other. Thus, two closed spaces divided by the first film portion 51 are formed inside the exterior material 22. The electrode bodies 40 are individually sealed in the respective closed spaces.

[0048] Figure 6 is a view showing a developed state of one sheet of stacked film constituting the exterior material 22. As shown in Figure 6 the exterior material 22 is a band shape in which the second film portion 52, the first film portion 51, and the third film portion 53 are joined in this order. The boundaries of the respective film portions 50 are folded back along the fold-back lines L1, L2 extending in the width direction. At the boundary between the first film portion 51 and the second film portion 52, the second film portion 52 is folded back to the first film portion 51 side along the fold-back line L1. At the boundary between the first film portion 51 and the third film portion 53, the third film portion 53 is folded back to the first film portion 51 side along the fold-back line L2. Thus, the exterior material 22 is corrugated and folded, the plurality of film portions 50 are formed, and the fold-back positions of the corrugated and folded stacked film are provided on one side and the other side in the height direction.

[0049] In the state in which the exterior material 22 is corrugated and folded, two sides in the width direction W of the four sides of the battery cell 20 constituting the outer peripheral portion are the lead-out sides of the electrode leads 26, and the two sides in the height direction H are the fold-back positions of the corrugated and folded stacked film.

[0050] On one side in the width direction W of the battery cell 20, two first electrode leads 26A extending from the positive electrode of the two electrode bodies 40 (40A, 40B) protrude in the width direction W. The two first electrode leads 26A are arranged in a state of protruding from the same height and being close to each other. Also, on the other side in the width direction W of the battery cell 20, two second electrode leads 26B extending from the negative electrode of the two electrode bodies 40 (40A, 40B) protrude in the width direction W. The two second electrode leads 26B are arranged in a state of protruding from the same height and being close to each other.

[0051] Thus, on both ends in the width direction W of the battery cell 20, two electrode leads 26 of the same polarity are arranged in a state of being close to each other, and are welded to the bus bars 30 (refer to Figure 4 ) arranged on the side of the battery cell 20.

[0052] The bus bars 30 are formed, for example, in a plate shape in which the width direction W of the battery cell 20 is the plate thickness direction, and extend in the stacking direction (thickness direction D) of the battery cell 20. Inside the module case 16, a plurality of bus bars 30 are arranged on each of the one side and the other side in the width direction W of the battery cell 20. As an example, each electrode lead 26 is inserted into a through-hole 32 (refer to Figure 4 ) which is a groove-shaped through-hole that penetrates the bus bar 30 in the plate thickness direction, and is welded to the surface of the bus bar 30 in a state of being folded back toward the bus bar 30 at the end portion protruding from the through-hole 32. In the present embodiment, the two electrode leads 26 arranged close to each other are overlapped on the surface of the bus bar 30, and are joined by simultaneous welding. By this, the two electrode bodies 40 (40A, 40B) can be electrically connected in series.

[0053] Also, the configuration is not limited to the above, and a configuration in which the positive electrode of the first electrode body 40A and the negative electrode of the second electrode body 40B are opposed to each other, and the two electrode bodies are connected in series can be adopted. Alternatively, the electrode lead 26 extending from the first electrode body 40A and the electrode lead 26 extending from the second electrode body 40B can be arranged at different heights, and each electrode lead 26 can be welded to different positions of the bus bar 30.

[0054] In one example of the present embodiment, the sealed first electrode body 40A and the second electrode body 40B of the battery cell 20 are electrically connected in parallel. Thus, on one side in the width direction W of the battery cell 20, the first electrode body 40A and the two first electrode leads 26A extending from the second electrode body 40B are connected to each other via the bus bar 30. The two first electrode leads 26A are arranged close to each other at the same height position inside the module case 16. Thus, the two first electrode leads 26A can be easily welded to each other on the bus bar 30. Also, on the other side in the width direction of the battery cell 20, the two second electrode leads 26B are similarly connected to each other.

[0055] The vehicle width direction length CW1 of the battery cell 20 is, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm to 900 mm, 1000 mm or more, the length CW2 of the region in which the electrode bodies are housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm 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. In addition, 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 electrode lead (terminal) 26 is 40 mm to 50 mm, 50 mm to 60 mm, 60 mm to 70 mm.

[0056] As described above, in the battery cell 20 of the present embodiment, since the plurality of electrode bodies 40 constituting the positive electrode and the negative electrode are stacked with the film portions 50 formed of the laminated film interposed therebetween, one film portion 50 is arranged between the adjacent electrode bodies 40 in the stacking direction. Thus, the battery cell 20 can join the outer peripheral portions of the plurality of film portions 50 laminated to each other, and seal the plurality of electrode bodies 40 integrally. As a result, since the adjacent electrode bodies 40 are divided by one film portion 50, the arrangement of the laminated film sealing the electrode bodies 40 can be optimized, and the size of the package can be reduced.

[0057] In addition, in the present embodiment, the plurality of film portions 50 are configured by alternately laminating the embossed film portions constituted by the embossed surfaces forming the housing portions of the electrode bodies 40 and the planar film portions having a flat surface. Thus, the housing of the battery cell 20 can be approximated to the stacked state of the battery cell constituting the single cup embossed structure, and can be combined with other battery cells constituting the single cup embossed structure. As a result, the versatility of the battery cell 20 can be improved.

[0058] In addition, in the present embodiment, the plurality of film portions 50 are constituted by one laminated film folded in a corrugated shape. Thus, it is not necessary to pre-cut each film portion 50 into one film shape, and the defects such as positional displacement or slackening caused at the time of pre-cutting can be reduced. As a result, the yield of the laminated film can be improved, and the productivity of the battery cell 20 can be improved.

[0059] In addition, in the present embodiment, the electrode body 40 is connected to the electrode lead 26 protruding in the width direction W at both end portions in the width direction W. In addition, the plurality of film portions 50 are provided with the return positions of the corrugated folding at one side and the other side in the height direction H orthogonal to the width direction W. Therefore, in the battery cell 20, the return position of the corrugated folding is provided at the other side orthogonal to the leading edge of the electrode lead 26 in the outer peripheral portion of the battery cell 20. As a result, the electrode lead 26 does not interfere with the return position of the laminated film, and thus the sealing process of the electrode body 40 becomes easy, and the productivity of the battery cell 20 is improved.

[0060] In addition, the battery cell 20 according to the present embodiment integrally seals a plurality of electrode bodies 40, and thus substantially integrates a plurality of battery elements each composed of a single cell. In addition, the electrode leads extending from the adjacent electrode bodies 40 can be arranged close to each other, and the connection of the electrode leads to each other can be performed at a short distance. Therefore, the battery cell 20 can be used to miniaturize and integrate a plurality of electrode bodies electrically connected in series or in parallel.

[0061] In the battery module 11 according to the present embodiment, the package of the battery cell 20 can be miniaturized as described above, and thus the volume of the state in which a plurality of battery cells 20 are laminated in the module case can be reduced. As a result, the package of the battery module 11 can be miniaturized.

[0062] The embodiment of the present application has been described above, but the present application is not limited to this. For example, the battery cell 20 according to the above-described embodiment adopts a configuration in which two electrode bodies are integrally sealed, and a configuration in which three or more electrode bodies are integrally sealed can also be adopted.

[0063] In addition, in the above-described embodiment, the return position of the corrugated folding of the laminated film is arranged at one side and the other side in the height direction H of the battery cell 20, but is not limited to this. For example, the return position of the corrugated folding of the laminated film can be arranged at one side and the other side in the width direction W of the battery cell 20. In this case, an opening for the electrode lead 26 to pass through can be formed at the return position of the laminated film.

[0064] In addition, in the above-described embodiment, the plurality of film portions 50 are composed of one laminated film that is corrugated, but are not limited to this. The plurality of film portions 50 can be composed by laminating a plurality of laminated films.

Claims

1. A battery cell, characterized by, The battery is configured by laminating a plurality of electrode bodies that constitute positive and negative electrodes with film portions formed of laminated films, joining outer peripheral portions of the laminated plurality of film portions to each other, and integrally sealing the plurality of electrode bodies.

2. The battery cell of claim 1, wherein, The plurality of film portions are configured by alternately laminating embossed film portions constituted by embossed surfaces that form accommodation portions of the electrode bodies and planar film portions that are planar.

3. The battery cell according to claim 1 or 2, characterized in that The plurality of film portions are constituted by one laminated film that is corrugated and folded.

4. The battery cell of claim 3, wherein, The electrode bodies are connected to electrode leads that protrude in the first width direction at end portions in at least one of the first width directions, The plurality of film portions are provided with the folded-back positions of the corrugated and folded film at one and the other of a second width direction that is orthogonal to the first width direction.

5. A battery module, characterized by, A plurality of the battery cells of claim 1 or 2 are laminated with each other and accommodated in a module case, and the plurality of battery cells are electrically connected to each other.

Images