Battery module

Abstract

This battery module is provided with: a plurality of battery cells having a laminated film that contains a metal layer and a heat-sealing layer, that accommodates an electrode body, and that has the heat-sealing layer at the peripheral edge thereof joined; a case that accommodates the battery cells in a state in which the battery cells are stacked in the thickness direction; and a heat conduction material which is provided on the inner wall of the case so as to be in contact with the metal layer exposed from the peripheral portion, and which dissipates heat from the battery cells.

Description

Technical Field

[0001] The present invention relates to a battery module. Background Art

[0002] A battery module (battery module) is conventionally known, which is constructed so that heat dissipation of a single battery cell (battery unit) is promoted by heat conduction through at least a portion of a sealed portion of a single battery cell casing (casing) where no electrode terminals are arranged (for example, refer to Japanese Patent Application No. 2011-504286). Summary of the invention

[0003] However, if the thermally conductive member is a dedicated member separate from the members constituting the battery cell, the heat conduction path for releasing the heat inside the battery cell to the outside becomes discontinuous inside the battery cell, and heat dissipation from the inside of the battery cell to the outside may become insufficient.

[0004] Therefore, an object of the present invention is to obtain a battery module capable of sufficiently ensuring heat dissipation from the inside of a battery cell to the outside.

[0005] In order to achieve the above-mentioned object, a battery module according to a first aspect of the present invention comprises:

[0006] A plurality of battery cells having a laminate film, the laminate film being composed of a metal layer and a heat seal layer, accommodating an electrode body and having the heat seal layer bonded at the peripheral edge;

[0007] a housing for accommodating the battery cells in a stacked state in a thickness direction; and

[0008] A heat conductive material is provided on the inner wall of the case so as to be in contact with the metal layer exposed from the peripheral portion, and dissipates heat from the battery cell.

[0009] According to the invention of the first scheme, a plurality of battery cells have a laminated film configured to include a metal layer and a heat-sealing layer. The laminated film accommodates the electrode body, and the heat-sealing layer at the peripheral portion thereof is joined. A plurality of battery cells are accommodated in a shell in a stacked state in the thickness direction, and a heat-conductive material in contact with the metal layer exposed from each peripheral portion is provided on the inner wall of the shell. Thus, the heat from the battery cell is dissipated. That is, the heat dissipation from the inside to the outside of the battery cell is fully ensured by the heat-conductive material in direct contact with the metal layer of the laminated film.

[0010] Furthermore, a battery module according to a second aspect of the present invention is the battery module according to the first aspect,

[0011] A plurality of recesses capable of accommodating the peripheral portion and the heat conductive material are formed on the inner wall of the housing.

[0012] The metal layer exposed from the peripheral portion is in contact with the heat conductive material inside the recess.

[0013] According to the invention of the second scheme, a plurality of recesses capable of accommodating the peripheral portion and the heat conductive material are formed on the inner wall of the housing. Furthermore, the metal layer exposed from the peripheral portion contacts the heat conductive material inside each recess. Therefore, each battery cell is fixed and the posture of each battery cell is stabilized.

[0014] Furthermore, a battery module according to a third aspect of the present invention is the battery module according to the second aspect,

[0015] The peripheral edge portions of two adjacent battery cells are accommodated in each of the recessed portions.

[0016] According to the third aspect of the invention, each recess houses the peripheral portions of two adjacent battery cells, so that the volume efficiency of each battery cell relative to the case is improved compared to a configuration in which the peripheral portions of each battery cell are housed one by one in each recess.

[0017] Furthermore, a battery module according to a fourth aspect of the present invention is the battery module according to the second or third aspect,

[0018] The front end surfaces of the peripheral edge portion accommodated in the recessed portion are configured to be located on the same plane.

[0019] According to the invention of the fourth embodiment, the top end surfaces of the peripheral portions contained in the recess are located on the same plane. That is, the lengths of the peripheral portions contained in the recess are consistent in each battery cell. Therefore, the volume efficiency of each battery cell relative to the housing is improved, and the posture of each battery cell is further stabilized.

[0020] Furthermore, a battery module according to a fifth aspect of the present invention is the battery module according to any one of the first to fourth aspects,

[0021] In the battery cell accommodated in the case, the thickness of the metal layer is formed to be thicker on the central portion side in the stacking direction than on the both end portions side in the stacking direction.

[0022] According to the invention of the fifth scheme, regarding the thickness of the metal layer of each battery cell housed in the housing, the center side of each battery cell in the stacking direction is thicker than the two end sides in the stacking direction. Here, it is known that in a stacked body formed by stacking a plurality of battery cells, the temperature is more likely to rise closer to the center side in the stacking direction, and it is known that the thicker the metal layer, the higher the thermal conductivity of the metal layer. Therefore, the heat dissipation from the inside to the outside of each battery cell is efficiently ensured in the stacking direction.

[0023] As described above, according to the present invention, it is possible to sufficiently ensure heat dissipation from the inside of the battery cell to the outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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 symbols represent like elements.

[0025] Figure 1 is a schematic plan view showing a battery electric vehicle equipped with a battery module according to the present embodiment;

[0026] Figure 2 is a schematic perspective view showing the structure of a battery module according to the present embodiment;

[0027] Figure 3 is a schematic plan view showing the structure of the battery module according to the present embodiment with the upper cover removed;

[0028] Figure 4 is a schematic front view showing the structure of a battery cell accommodated in a battery module according to the present embodiment as viewed from the thickness direction;

[0029] Figure 5A is a schematic cross-sectional view showing the internal structure of the battery module according to the first embodiment as viewed from the vehicle width direction;

[0030] Figure 5B is a schematic cross-sectional view showing the internal structure of a battery module according to a modification of the first embodiment as viewed from the vehicle width direction;

[0031] Figure 6 This is a schematic cross-sectional view showing the internal structure of a battery module according to the second embodiment as viewed from the vehicle width direction. DETAILED DESCRIPTION

[0032] Hereinafter, the embodiments of the present invention will be described in detail based on the accompanying drawings. In addition, for the convenience of description, the arrow UP appropriately shown in each figure is set as the vehicle upper direction, the arrow FR is set as the vehicle front direction, and the arrow LH is set as the vehicle left direction. Therefore, in the following description, when the up-down, front-back, and left-right directions are recorded without special description, the up-down direction of the vehicle upper-down direction, the front-back direction of the vehicle front-back direction, and the left-right direction of the vehicle left-right direction (vehicle width direction) are indicated. In addition, the left-right direction is synonymous with the vehicle width direction.

[0033] In addition, the size of the components in each figure is conceptual, and the relative relationship between the sizes of the components is not limited thereto. In addition, in the present embodiment, the numerical range represented by "-" means a range including the numerical values ​​recorded before and after "-" as the minimum value and the maximum value, respectively. In addition, in the numerical range recorded in stages in the present embodiment, the upper limit value or lower limit value recorded in a certain numerical range can also be replaced by the upper limit value or lower limit value of the numerical range recorded in other stages.

[0034] like Figure 1 As shown, the vehicle 100 involved in the present embodiment is, as an example, a battery electric vehicle (BEV) equipped with a battery pack 10 under the floor. In the vehicle 100, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are arranged on the front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are arranged on the rear side of the battery pack 10.

[0035] Therefore, 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. Furthermore, by supplying power to motor 108 via inverter 112, the rear wheels rotate and vehicle 100 travels.

[0036] A charging port 116 is provided at the right side of the rear portion of the vehicle 100 . Therefore, by connecting a charging plug of an external charging device (not shown) to the charging port 116 , electric power is stored in the battery pack 10 via the charger 114 .

[0037] In addition, the illustrated vehicle 100 is a rear-wheel drive vehicle with the motor 108 mounted at the rear, but the vehicle is not limited thereto, and may be a front-wheel drive vehicle with the motor 108 mounted at the front. In addition, a vehicle may be provided with a pair of motors 108 mounted at the front and rear, or a vehicle may be provided with a hub motor at each wheel. In other words, the arrangement and structure of the components constituting the vehicle 100 are not limited to the above-described configuration.

[0038] 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, on the right side of the vehicle 100, five battery modules 11 are arranged with the thickness direction facing the front-rear direction, and on the left side of the vehicle 100, five battery modules 11 are arranged with the thickness direction facing the front-rear direction. In addition, each battery module 11 is electrically connected.

[0039] like Figure 2As shown, the battery module 11 is formed into a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. In addition, the housing 30 as the outer shell of the battery module 11 is formed of an aluminum alloy. For example, the housing 30 of the battery module 11 is formed by joining aluminum die castings at both ends of an aluminum alloy extrusion by laser welding or the like.

[0040] 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 21 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.

[0041] 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 front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the up-down direction of, for example, 80 mm to 110 mm.

[0042] like Figure 3 As shown, a plurality of battery cells 20 are housed in the battery module 11 so as to be arranged with the thickness direction facing the front-rear direction. In this embodiment, as an example, 24 battery cells 20 are arranged with the thickness direction facing the front-rear direction and bonded to each other.

[0043] A flexible printed circuit (FPC) 21 is disposed above the battery cell 20 and in the center in the front-rear direction. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the length direction, and thermistors 23 are provided at both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cell 20, but is pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0044] In addition, one or more buffers (not shown) are accommodated inside the battery module 11. The buffer is, for example, 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 in the longitudinal direction and the central part in the longitudinal direction of the battery module 11.

[0045] like Figure 4 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 formed by laminating electrodes (negative and positive electrodes) and separators disposed between the electrodes, and is sealed by a laminate film 22 as an outer body.

[0046] As the electrode, for example, an electrode having a layer containing an electrode active material formed on one or both sides of a current collector is used. As the separator, for example, a microporous film made of a resin such as polyethylene is used. The laminate film 22 is a laminate having a metal layer containing a metal such as aluminum and a heat seal layer.

[0047] In this embodiment, as an example, the electrode body receiving portion is formed by folding the embossed (embossed) sheet-shaped laminate film 22 and bonding the heat-sealed layers at its peripheral edges together. In addition, the laminate film 22 can be formed into a single-cup embossed structure with one embossed portion and a double-cup embossed structure with two embossed portions. Figure 4 , a single cup embossing structure with a drawing depth of about 8 mm to 10 mm is shown.

[0048] in addition, Figure 4 The lower ends of the peripheral portions of the battery cell 20 at both ends in the longitudinal direction are bent, as shown in FIG. Figure 5A , Figure 5B As shown, the peripheral edge portion 24 at the lower end of the battery cell 20 is also bent forward or backward. In addition, the metal layer is exposed from the lower end surface (top end surface) 24A of the peripheral edge portion 24 at the lower end.

[0049] In addition, terminals (tabs) 26 are provided at both ends of the battery cell 20 in the longitudinal direction. In the present embodiment, as an example, each terminal 26 is provided at the substantially central portion of the battery cell 20 in the vertical direction, but each terminal 26 is not limited to this position, and may also be provided at a position offset upward or downward from the substantially central portion in the vertical direction. In addition, each terminal 26 is joined to a bus bar (not shown) by laser welding or the like.

[0050] The length CW1 of the battery unit 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 containing the electrode body 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.

[0051] 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.

[0052] Next, the internal structure of the battery module 11 having the above configuration will be described in more detail.

[0053] First Embodiment

[0054] First, the first embodiment will be described. Figure 5A As shown, at least the bottom wall 32 of the housing 30 of the battery module 11 is a double-layer structure having an outer wall 34 and an inner wall 36 formed to a predetermined thickness. In addition, a potting material 16 as a heat conductive material is filled to a predetermined height on the upper surface of the inner wall 36.

[0055] That is, the plurality of battery cells 20 are housed in the housing 30 in a state where the peripheral edge portions 24 at the lower end portions thereof are folded toward the front side or the rear side. The potting material 16 is filled at least to a height such that the entire folded peripheral edge portion 24 is immersed. Therefore, the metal layer exposed from the peripheral edge portion 24 of each battery cell 20 is in contact with the potting material 16. Thus, the heat inside each battery cell 20 is dissipated from the metal layer to the outside via the potting material 16.

[0056] also, Figure 5A Each terminal 26 of the four battery cells 20 shown (see Figure 4 ) For example, from the front side, the front side of the paper becomes the negative electrode, the positive electrode, the negative electrode, and the positive electrode. That is, from the front side, the back side of the paper becomes the positive electrode, the negative electrode, the positive electrode, and the negative electrode.

[0057] Furthermore, the peripheral edge portions 24 of the four battery cells 20 are bent in order, for example, from the front side to the front side, the rear side, the front side, and the rear side. In addition, although not shown in the figure, in the plurality of battery cells 20 accommodated in the housing 30, the thickness of the metal layer constituting the laminate film 22 is formed thicker on the central portion side in the stacking direction than on the both end portions in the stacking direction.

[0058] Next, the operation of the battery module 11 according to the first embodiment having the above-described configuration will be described.

[0059] like Figure 5A As shown, a plurality of battery cells 20 are accommodated in a case 30 in a stacked state in the thickness direction. The metal layer is exposed from the peripheral edge portion 24 of the plurality of battery cells 20. The potting material 16 is filled into the case 30 and provided at a predetermined height on the upper surface of the inner wall 36 in the bottom wall 32. The metal layer is in contact with the potting material 16.

[0060] Therefore, the metal layer constituting the laminate film 22 can function as a heat dissipation material to the potting material 16, and the heat from the inside of each battery cell 20 can be efficiently dissipated. In other words, the potting material 16 directly in contact with the metal layer can fully ensure the heat dissipation from the inside of each battery cell 20 to the outside (the cooling efficiency can be improved).

[0061] In addition, regarding the thickness of the metal layer of each battery cell 20 housed in the housing 30, the central part side in the stacking direction of each battery cell 20 is thicker than the two end parts in the stacking direction. Here, it is known that in a stacked body formed by stacking a plurality of battery cells 20, the temperature is more likely to rise closer to the central part side in the stacking direction, and it is known that the thicker the metal layer, the higher the thermal conductivity of the metal layer. Therefore, the heat dissipation on the central part side in the stacking direction where the temperature is likely to rise can be improved, and the heat dissipation from the inside to the outside of each battery cell 20 housed in the housing 30 can be efficiently (balancedly) ensured in the stacking direction.

[0062] Modifications

[0063] In addition, the method of bending the peripheral edge portion 24 of each battery cell 20 is not limited to Figure 5A The bending method shown can also be Figure 5B The bending method shown. That is, Figure 5B Each terminal 26 of the four battery cells 20 shown (see Figure 4 ) From the front side, the front side of the paper is the negative electrode, the negative electrode, the positive electrode, and the positive electrode. The terminals 26 are the positive electrode, the positive electrode, the negative electrode, and the negative electrode from the front side.

[0064] Furthermore, the peripheral edge portions 24 of the four battery cells 20 are bent toward the rear side, the front side, the rear side, and the front side in order from the front side. Therefore, in this case, even if the metal layers exposed from the peripheral edge portions 24 of the battery cells 20 face each other in the front-to-back direction (stacking direction), the metal layers have the same potential. Therefore, even if the metal layers are supposed to come into contact with each other, the risk caused by this can be reduced.

[0065] Second Embodiment

[0066] Next, a second embodiment will be described. Note that the same reference numerals are given to the same components as those of the first embodiment, and detailed descriptions thereof will be appropriately omitted.

[0067] like Figure 6As shown, in the second embodiment, a concave portion 38 (groove portion) having a rectangular shape in a plan view extending in the longitudinal direction (vehicle width direction) is formed on the inner wall 36 of the bottom wall 32 of the housing 30. The peripheral edge portion 24 of each battery cell 20 accommodated in the housing 30 is not bent but inserted into the interior of the concave portion 38. These are the only points that are different between the first embodiment and the second embodiment.

[0068] In addition, the recessed portion 38 shown in the figure is composed of a through hole 36A having a rectangular shape in a plan view formed in the inner wall 36 and the upper surface of the outer wall 34, but the present invention is not limited thereto, and the recessed portion 38 may be formed in a configuration formed at a predetermined depth on the upper surface of the inner wall 36. In addition, the inside of the recessed portion 38 is inevitably filled with the potting material 16. Therefore, the metal layer exposed from each peripheral portion 24 is in contact with the potting material 16 inside each recessed portion 38.

[0069] In addition, each of the peripheral edge portions 24 of two adjacent battery cells 20 is accommodated in each recess 38. And, the lower end surface 24A (see Figure 4 That is, in the process of manufacturing the battery cells 20, the top ends of the peripheral portions 24 of the battery cells 20 are collectively cut off, so that the lengths (heights) of the peripheral portions 24 accommodated in the recesses 38 are consistent.

[0070] in addition, Figure 6 Each terminal 26 of the four battery cells 20 shown (see Figure 4 )and Figure 5A As shown in FIG. 1 , the front side of the paper is the negative electrode, the positive electrode, the negative electrode, and the positive electrode. The terminals 26 are the positive electrode, the negative electrode, the positive electrode, and the negative electrode in the paper from the front side. The terminals 26 are not limited to this, and can also be connected to Figure 5B Same as shown.

[0071] Next, the operation of the battery module 11 according to the second embodiment having the above-described configuration will be described. The operation common to the first embodiment will be appropriately omitted.

[0072] like Figure 6 As shown, a plurality of recesses 38 capable of accommodating the peripheral edge 24 of each battery cell 20 and the potting material 16 are formed on the inner wall 36 of the bottom wall 32 of the housing 30. The metal layer exposed from the peripheral edge 24 of each battery cell 20 is in contact with the potting material 16 inside the recess 38. Therefore, the heat dissipation from the inside of each battery cell 20 to the outside can be fully ensured, and the position of each battery cell 20 accommodated in the housing 30 can be fixed, and the posture of each battery cell 20 can be stabilized.

[0073] Furthermore, each of the peripheral edge portions 24 of two adjacent battery cells 20 is accommodated in each recess 38. Therefore, compared with a configuration in which the peripheral edge portion 24 of each battery cell 20 is accommodated in each recess 38, the volume efficiency of each battery cell 20 relative to the housing 30 can be improved. The size of the battery module 11 can be made compact.

[0074] In addition, the lower end faces 24A of the peripheral portions 24 housed in the recesses 38 are located on the same plane, and the lengths (heights) of the peripheral portions 24 housed in the recesses 38 are consistent in the battery cells 20. Therefore, the volume efficiency of each battery cell 20 relative to the housing 30 can be improved, and the posture of each battery cell 20 can be further stabilized.

[0075] As mentioned above, the battery module 11 according to the present embodiment has been described based on the drawings, but the battery module 11 according to the present embodiment is not limited to the illustrated configuration, and can be appropriately modified in design without departing from the gist of the present invention.

[0076] For example, the metal layer at the peripheral portion 28 of the laminate film 22 is not limited to being exposed from the end surface 28A thereof, and may be exposed from other locations in the peripheral portion 28. In addition, the housing 30 may not be a double-layer structure. In this case, in the second embodiment, for example, the thickness of the outer wall 34 in the bottom wall 32 is formed thick, and a recess 38 of a predetermined depth is formed on the upper surface of the outer wall 34.

[0077] In addition, the type and size of the electrode body are not particularly limited, and are selected according to the scale and purpose of the battery cell 20. In addition, the number of electrodes and separators contained in the electrode body is not particularly limited, and is selected according to the scale and purpose of the battery cell 20. In addition, the vehicle 100 is not limited to a battery electric vehicle. As the vehicle 100, for example, it can also be a hybrid electric vehicle (HV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine.

Claims

1. A battery module comprising: A plurality of battery cells having a laminate film, the laminate film being composed of a metal layer and a heat seal layer, accommodating an electrode body and having the heat seal layer bonded at the peripheral edge; a housing for accommodating the battery cells in a stacked state in a thickness direction; and A heat conductive material is provided on the inner wall of the case so as to be in contact with the metal layer exposed from the peripheral portion, and dissipates heat from the battery cell.

2. The battery module according to claim 1, A plurality of recesses capable of accommodating the peripheral portion and the heat conductive material are formed on the inner wall of the housing. The metal layer exposed from the peripheral portion is in contact with the heat conductive material inside the recess.

3. The battery module according to claim 2, The peripheral edge portions of two adjacent battery cells are accommodated in each of the recessed portions.

4. The battery module according to claim 3, The front end surfaces of the peripheral edge portion accommodated in the recessed portion are configured to be located on the same plane.

5. The battery module according to any one of claims 1 to 4, In the battery cell accommodated in the case, the thickness of the metal layer is formed to be thicker on the central portion side in the stacking direction than on the both end portions side in the stacking direction.

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