Battery pack

Abstract

To obtain a battery pack capable of improving cooling efficiency.SOLUTION: A battery pack 20 includes a plurality of battery cells each having a positive electrode terminal and a negative electrode terminal, a battery case 22 accommodating the plurality of battery cells, and a bus bar including a lid portion 24 made of an insulator and provided to the battery case 22, a main body portion embedded in the lid portion 24, and a connection terminal provided at an end portion of the main body portion, exposed from an inner surface of the lid portion 24 facing the plurality of battery cells, and electrically connected to the positive electrode terminals and the negative electrode terminals of the plurality of battery cells. The outer surface of the lid portion 24 is in contact with the cooler 18.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] A battery pack including a pack case having a pack tray that supports the lower part of a battery module and a pack cover that covers the battery module and is in contact with the upper end surface of the battery module, and a heat sink attached to the upper part of the pack cover has been known for some time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-126533 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in this battery pack, the heat sink contacts a pack cover that is separate from the bus bar, so the distance between the heat sink and the bus bar and battery module is large, reducing the cooling efficiency for the bus bar and battery module.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a battery pack that can improve cooling efficiency. [Means for solving the problem]

[0006] In order to achieve the above object, a battery pack of a first aspect according to the present invention comprises: a plurality of battery cells or a plurality of battery modules each having a positive electrode terminal and a negative electrode terminal; a battery case accommodating the plurality of battery cells or the plurality of battery modules; a lid portion made of an insulator and provided for the battery case; a main body portion embedded in the lid portion; and a bus bar provided at an end of the main body portion, exposed from an inner surface of the lid portion facing the plurality of battery cells or the plurality of battery modules, and having connection terminals electrically connected to the positive electrode terminals and negative electrode terminals of the plurality of battery cells or the plurality of battery modules, and the outer surface of the lid portion is in contact with a cooler.

[0007] According to the first aspect of the invention, a battery case houses multiple battery cells or multiple battery modules, each having a positive electrode terminal and a negative electrode terminal, and a lid made of an insulator is provided for the battery case. Furthermore, a bus bar body is embedded in the lid, and connection terminals provided at the ends of the bus bar body are exposed from the inner surface of the lid facing the multiple battery cells or multiple battery modules, and are electrically connected to the positive and negative electrode terminals of the multiple battery cells or multiple battery modules. The outer surface of the lid is in contact with a cooler.

[0008] That is, according to the present invention, the bus bar is embedded in the lid of the battery case, which allows for efficient heat exchange with the cooler, thereby improving the cooling efficiency of the battery pack compared to a configuration in which the lid of the battery case and the bus bar are separate.

[0009] A second aspect of the battery pack according to the present invention is the battery pack of the first aspect, wherein the connection terminals of the bus bar are electrically connected to the positive electrode terminal and the negative electrode terminal via joining tabs, respectively, and are formed to a size that does not protrude from the joining tabs.

[0010] According to the second aspect of the invention, the bus bar connection terminals are electrically connected to the positive and negative electrode terminals of the battery cells or battery modules via the joining tabs, respectively, and are sized so that they do not protrude from the joining tabs. This ensures better insulation between the electrode terminals of the battery cells or battery modules than when the bus bar connection terminals protrude from the joining tabs.

[0011] Furthermore, a third aspect of the battery pack according to the present invention is the battery pack of the first or second aspect, wherein the main body of the bus bar embedded in the lid is spaced from the outer surface and the side surface of the lid by at least twice the thickness of the main body.

[0012] According to the third aspect of the invention, the body of the bus bar embedded in the lid is spaced from the outer surface and side surface of the lid by at least twice the thickness of the body, thereby ensuring better insulation between electrode terminals in multiple battery cells or multiple battery modules compared to when the body of the bus bar embedded in the lid is only spaced from the outer surface and side surface of the lid by approximately the same amount as the thickness of the body.

[0013] Furthermore, a fourth aspect of the battery pack according to the present invention is a battery pack according to any one of the first to third aspects, in which a thermally conductive member that contacts the plurality of battery cells or the plurality of battery modules is provided on the inner surface of the lid portion other than at a location where the connection terminals are exposed.

[0014] According to the fourth aspect of the invention, a heat-conducting member that contacts the battery cells or battery modules is provided on the inner surface of the lid, other than at a location where the connection terminals are exposed. This improves heat dissipation in the battery cells or battery modules compared to when the heat-conducting member that contacts the battery cells or battery modules is not provided on the inner surface of the lid.

[0015] In addition, a fifth aspect of the battery pack according to the present invention is a battery pack according to any one of the first to fourth aspects, wherein the lid portion is composed of a lid portion main body having an inner surface facing the plurality of battery cells or the plurality of battery modules, and an exterior portion formed of a high-strength material stronger than the lid portion main body and covering the surfaces of the lid portion main body except for the inner surface.

[0016] According to the fifth aspect of the invention, the lid is composed of a lid main body having an inner surface facing the plurality of battery cells or the plurality of battery modules, and an exterior part made of a high-strength material that is stronger than the lid main body and that covers the surfaces of the lid main body except for the inner surface, thereby improving the rigidity of the lid and suppressing or preventing warping of the lid.

[0017] In addition, a battery pack according to a sixth aspect of the present invention includes: a plurality of battery cells or a plurality of battery modules each having a positive electrode terminal and a negative electrode terminal; a battery case accommodating the plurality of battery cells or the plurality of battery modules; and a bus bar made of an insulator, the bus bar having a lid portion provided for the battery case; a main body portion embedded in the lid portion; and a connection terminal provided at an end of the main body portion and embedded in the lid portion, the connection terminal being at least partially exposed through a hole formed in the lid portion, wherein the positive and negative electrode terminals of the plurality of battery cells or the plurality of battery modules are inserted into the hole and electrically connected to the connection terminal, and the outer surface of the lid portion is in contact with a cooler.

[0018] According to a sixth aspect of the invention, a battery case houses multiple battery cells or multiple battery modules, each having a positive electrode terminal and a negative electrode terminal, and a lid made of an insulator is provided for the battery case. Furthermore, busbar bodies are embedded in the lid, and connection terminals provided at the ends of the busbar bodies are also embedded in the lid, with at least a portion of the connection terminals exposed through holes formed in the lid. The positive and negative electrode terminals of the multiple battery cells or multiple battery modules are inserted through the holes and electrically connected to the connection terminals, and the outer surface of the lid is in contact with a cooler.

[0019] That is, according to the present invention, the bus bar is embedded in the lid of the battery case, which allows for efficient heat exchange with the cooler, thereby improving the cooling efficiency of the battery pack compared to a configuration in which the lid of the battery case and the bus bar are separate.

[0020] A battery pack according to a seventh aspect of the present invention is the battery pack according to any one of the first to sixth aspects, wherein the outer surface of the lid is in contact with the cooler over the entire surface.

[0021] According to the seventh aspect of the invention, the outer surface of the lid is in contact with the cooler over the entire surface, thereby improving the cooling efficiency of the battery pack compared to when only a portion of the outer surface of the lid is in contact with the cooler. [Effects of the Invention]

[0022] As described above, according to the present invention, the cooling efficiency for the battery pack can be improved. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic front view showing a battery pack installation structure according to a first embodiment. [Figure 2] 1 is a schematic front view showing the internal structure of a battery pack according to a first embodiment. [Figure 3] 3 is a schematic bottom view showing the inner surface of the lid of the battery pack according to the first embodiment. FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along the line XX in FIG. 3. [Figure 5] 1 is a schematic perspective view showing a battery cell of a battery pack according to a first embodiment. [Figure 6] FIG. 1 is a schematic bottom view showing the internal structure of a battery pack according to a first embodiment; [Figure 7] FIG. 10 is a schematic bottom view showing the inner surface of the lid of the battery pack according to the second embodiment. [Figure 8] FIG. 10 is a schematic front view showing the internal structure of a battery pack according to a third embodiment. [Figure 9] FIG. 10 is a schematic front view showing the internal structure of a battery pack according to a fourth embodiment. [Figure 10] FIG. 10 is a schematic front view showing the internal structure of a battery pack according to a fifth embodiment. [Figure 11] FIG. 13 is a schematic plan view showing the internal structure of a battery pack according to a sixth embodiment. [Figure 12] 12(A) is a schematic bottom view showing the internal structure of a battery pack according to a seventh embodiment, and FIG. 12(B) is a schematic cross-sectional view taken along line YY in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. For convenience of explanation, the arrow UP shown in each drawing indicates the upward direction of the vehicle, the arrow FR indicates the forward direction of the vehicle, and the arrow RH indicates the rightward direction of the vehicle. Furthermore, in the following description, unless otherwise specified, when up / down, front / rear, and left / right directions are mentioned, they refer to up / down, front / rear, left / right of the vehicle. Furthermore, the left / right direction is synonymous with the vehicle width direction.

[0025] First Embodiment First, a first embodiment will be described. As shown in Fig. 1, a vehicle 10 such as an electric vehicle is provided with a substantially flat floor 12, and a substantially flat cooler 18 is disposed below the floor 12. A battery pack 20 according to the first embodiment is disposed below the cooler 18 mounted on the vehicle 10.

[0026] More specifically, a pair of left and right side members 14 having a generally hat-shaped configuration in front view are provided on the underside of the floor 12 on the outer side in the vehicle width direction of the cooler 18. That is, a flange portion 14A that protrudes outward and inward in the vehicle width direction is integrally formed on the upper end of each side member 14, and the flange portion 14A is attached to the underside of the floor 12 by welding or the like.

[0027] A plurality of through holes (not shown) for inserting bolts are formed in a row in the front-to-rear direction in the center of the vehicle width direction at the lower end portion 14B of each side member 14, and a plurality of weld nuts 15 are provided coaxially with each through hole on the upper surface of the lower end portion 14B. The vehicle 10 is also provided with a support base 16 that supports the battery pack 20 from below.

[0028] The support base 16 has a flat plate portion 16A of a predetermined thickness on which the battery pack 20 is placed, and protruding portions 16B of a predetermined thickness integrally formed on both outer ends of the flat plate portion 16A in the vehicle width direction. The protruding portions 16B protrude upward in a generally inverted "L" shape when viewed from the front, and a plurality of through holes (not shown) for inserting bolts are formed in the center of the protruding portion 16B in the vehicle width direction, lined up in the front-rear direction.

[0029] Furthermore, lower ends of support members 16C are attached to the lower portions of the left and right side surfaces of flat plate portion 16A facing outward in the vehicle width direction, and upper ends of support members 16C are attached to the outer ends in the vehicle width direction of the lower surfaces of overhanging portions 16B. In other words, the outer ends in the vehicle width direction of overhanging portions 16B are configured to be supported by flat plate portion 16A via support members 16C.

[0030] The battery pack 20 has a battery case 22, which will be described later, and flange portions 22A (shown only in FIG. 1) that protrude outward in the vehicle width direction are integrally formed on left and right side walls 22S of the battery case 22 that face outward in the vehicle width direction. Each flange portion 22A is formed at a height position such that, when the battery case 22 (battery pack 20) ​​is placed on the flat plate portion 16A, its lower surface overlaps from above with the upper surface of the protruding portion 16B. Each flange portion 22A has a plurality of through holes (not shown) for inserting bolts formed in a row in the front-rear direction.

[0031] Therefore, when the battery pack 20 (battery case 22) is placed on the flat plate portion 16A, the support base 16 supports each flange portion 22A with each protrusion portion 16B, and is configured to be attached to the left and right side members 14 by contacting the upper surface of each flange portion 22A with the lower surface of the lower end portion 14B of each side member 14, and inserting multiple bolts 17 from the lower side of each protrusion portion 16B into each through hole and screwing them into each weld nut 15.

[0032] As a result, the upper surface (outer surface) of the lid portion 24 of the battery pack 20, which will be described later, is configured to come into full contact with the cooler 18 from below with a predetermined pressure. Of the surfaces of the lid portion 24, the surface facing the battery cells 30 housed in the battery case 22 is the inner surface, and the surface facing the opposite side to the inner surface is the outer surface, and the upper surface is not always the outer surface.

[0033] 2, the battery pack 20 has a housing-like battery case 22 having side walls (including left and right side walls 22S) of a predetermined height integrally provided on the peripheral edges of a rectangular, flat bottom wall whose longitudinal direction is the vehicle width direction and which is open at the top, and a rectangular, flat lid 24 that closes the upper opening of the battery case 22. Note that "closing" the lid 24 here includes both a case where the opening of the battery case 22 is completely closed and a case where only a portion of the opening of the battery case 22 is closed.

[0034] The battery case 22 is made of an insulating material (a resin material that can be easily molded into one piece: for example, an engineering plastic such as polyamide), and houses multiple battery cells 30 (six are shown in Figure 2 for simplicity) each having a positive electrode terminal 30A and a negative electrode terminal 30B.

[0035] The multiple battery cells 30 are arranged side by side with the longitudinal direction of the battery case 22 (vehicle width direction) as the thickness direction, and are restrained by restraining jigs 32. The restraining jigs 32 are arranged on both longitudinal end sides of the battery case 22 and comprise flat restraining plates 32A that are placed on the battery cells 30 on those end sides, and a pair of front and rear restraining bands 32B that extend in the longitudinal direction of the battery case 22 and integrally connect the upper and lower parts of the restraining plates 32A together, respectively.

[0036] Lid 24 is made of an insulator (preferably the same resin material as battery case 22 to match thermal expansion characteristics), and is embedded without gaps and without exposing main body 26A of bus bar 26 to the outside, as shown in Figures 2 to 4. Bus bar 26 is made of metal, and is preferably made of copper, which has good conductivity, from the perspective of improving cooling performance.

[0037] Connection terminals 26B are integrally provided at both ends of the main body 26A of the bus bar 26, and the lower surfaces of the connection terminals 26B are exposed from the inner surface of the lid 24 that faces the multiple battery cells 30 in the vertical direction. Note that in Figure 2 and Figures 8 to 11 described below, each connection terminal 26B is shown simply as a flat plate.

[0038] 3, the main body 26A of each bus bar 26 is embedded at an angle (inclined at a predetermined angle) relative to the front-to-rear direction in bottom view (plan view). As shown in Fig. 6, the connection terminal 26B of each bus bar 26 is in contact with and electrically connected to the positive electrode terminal 30A of one adjacent battery cell 30 and the negative electrode terminal 30A of the other adjacent battery cell 30, respectively. A thermostat 28, which will be described later, is not shown in Fig. 6.

[0039] Furthermore, a total positive junction box 36 and a total negative junction box 38 are electrically connected to the most upstream and most downstream ends of the current path formed by the multiple bus bars 26 via flexible power cables 37. The total positive junction box 36 and the total negative junction box 38 are also disposed inside the battery case 22 (see Figures 2 and 6).

[0040] 2, a detector (battery ECU) 40 is provided outside the battery pack 20 to detect the voltage and temperature of the connection terminals 26B of each bus bar 26. That is, a thermostat 28 is arranged in contact with each connection terminal 26B to accurately measure the temperature of the bus bar 26 (see FIG. 3), and each connection terminal 26B and the thermostat 28 are electrically connected to the detector 40 by a detection wire 27. The detection wire 27 and the thermostat 28 are also embedded in the lid 24, and only a portion of the detection wire 27 for connection to the detector 40 is drawn out from the side wall of the lid 24.

[0041] 4, main body 26A of bus bar 26 embedded in lid portion 24 is embedded at a distance of at least twice the thickness (plate thickness D) of main body 26A from the top surface (outer surface) and side surface of lid portion 24. That is, distance W1 from the top surface of lid portion 24 to the top surface of main body 26A and distance W2 from the side surface of lid portion 24 to the side surface of main body 26A are set to at least twice the thickness (plate thickness D) of main body 26A.

[0042] 5 and 6, connection terminal 26B of bus bar 26 is electrically connected to positive electrode terminal 30A and negative electrode terminal 30B via joining tabs 34. Joining tabs 34 are also made of metal, and are preferably made of copper, which has good electrical conductivity, from the viewpoint of improving cooling performance.

[0043] Each joining tab 34 is formed in the shape of a rectangular flat plate with the longitudinal direction in the front-to-rear direction in a plan view, and is larger than the positive electrode terminal 30A and the negative electrode terminal 30B. In other words, each positive electrode terminal 30A and each negative electrode terminal 30B is formed in a size that does not protrude from each joining tab 34.

[0044] In order to ensure insulation between the positive electrode terminals 30A and negative electrode terminals 30B of adjacent battery cells 30, and between the positive electrode terminal 30A and negative electrode terminal 30B of the battery cell 30 itself, it is preferable that the joining tabs 34 be spaced apart by 5 mm or more (when no insulating member is provided between them).

[0045] Next, the operation of the battery pack 20 according to the first embodiment configured as above will be described.

[0046] As described above, a plurality of battery cells 30 each having a positive electrode terminal 30A and a negative electrode terminal 30B are housed in a housing-shaped battery case 22 made of an insulator (resin material), and the opening of the battery case 22 is closed by a lid 24 made of an insulator (resin material).

[0047] Furthermore, the main body 26A of the bus bar 26 is embedded in the lid portion 24, and the connection terminals 26B provided at both ends of the main body 26A of the bus bar 26 are exposed from the inner surface of the lid portion 24 facing the multiple battery cells 30, and are electrically connected to the positive electrode terminals 30A and negative electrode terminals 30B of the multiple adjacent battery cells 30.

[0048] The top surface (outer surface) of the lid portion 24 is in contact with the cooler 18 mounted on the vehicle 10 at a predetermined pressure. Therefore, compared to a configuration in which the lid portion 24 of the battery case 22 and the bus bar 26 are separate, the heat path from the cooler 18 to the battery cells 30 can be shortened, and as a result of this reduced thermal resistance, each battery cell 30 can be cooled more effectively. In other words, the cooling efficiency of the battery pack 20 can be improved.

[0049] Furthermore, compared to a configuration in which the lid portion 24 of the battery case 22 and the bus bar 26 are separate bodies, the surface area of ​​the bus bar 26 that comes into contact with the lid portion 24 of the battery case 22 can be increased. This makes it easier for the bus bar 26 to exchange heat with the cooler 18 than in the past, and allows the bus bar 26 and each battery cell 30 to be cooled more effectively. In other words, the cooling efficiency of the battery pack 20 can be improved.

[0050] In particular, the upper surface of the lid portion 24 is configured to be in contact with the cooler 18 over its entire surface at a predetermined pressure, and therefore, compared to a configuration in which only a portion of the upper surface of the lid portion 24 is in contact with the cooler 18, the lid portion 24 and each bus bar 26 embedded in the lid portion 24 can be cooled directly and effectively, and the cooling efficiency of the battery pack 20 can be more effectively improved.

[0051] Note that, because battery case 22 and lid portion 24 are made of resin, it is possible to reduce the weight of battery pack 20. Furthermore, as described above, because the entire top surface of lid portion 24 contacts cooler 18 with a predetermined pressure (cooler 18 can be used as a reinforcing member), warping of lid portion 24 can be suppressed or prevented even though lid portion 24 is made of resin, and even if lid portion 24 is formed thin to further reduce the weight, it is possible to suppress or prevent insufficient strength and sealing performance.

[0052] Furthermore, because the battery pack 20 is configured to contact the cooler 18 from below, it is possible to improve the ease of attaching and detaching the battery pack 20 to and from the vehicle 10. In other words, since it is not necessary to detach the cooler 18 when attaching or detaching the battery pack 20, it is possible to reduce the time and amount of work required for the attachment and detachment.

[0053] Furthermore, because the bus bar 26, the detection wire 27, and the thermostat 28 are embedded in the lid portion 24 and integrated with the lid portion 24, the number of parts can be reduced compared to when the bus bar 26, the detection wire 27, and the thermostat 28 are separate from the lid portion 24. In other words, there is no need to provide a connector or the like for connecting the detection wire 27 inside the battery case 22. This also eliminates the need for space for wiring the detection wire 27, allowing for space savings inside the battery case 22.

[0054] Furthermore, although not shown, if the entire bus bars are exposed from the inner surface of the lid portion 24, it is necessary to leave a wide gap between the battery cells 30 to ensure their insulation. However, in the multiple bus bars 26 according to the first embodiment, the main body 26A, excluding the connection terminals 26B, of each bus bar is embedded in the lid portion 24, ensuring their insulation, and therefore there is no need to leave a wide gap between the battery cells 30 (the battery cells 30 can be arranged close to each other). This makes it possible to reduce the size of the battery pack 20 at least in the left-right direction.

[0055] Furthermore, the connection terminals 26B of the busbar 26 are electrically connected to the positive electrode terminals 30A and negative electrode terminals 30B of adjacent battery cells 30 via the joining tabs 34, respectively, but are formed to a size that does not protrude from the joining tabs 34. Therefore, compared to when the connection terminals 26B of the busbar 26 protrude from the joining tabs 34, it is possible to ensure good insulation between the positive electrode terminals 30A and negative electrode terminals 30B of adjacent battery cells 30, and between the positive electrode terminals 30A and negative electrode terminals 30B of the battery cells 30 themselves.

[0056] Furthermore, the main body 26A of the bus bar 26 embedded in the lid portion 24 is spaced from the top surface and side surfaces of the lid portion 24 by at least twice the thickness of the main body 26A. Therefore, compared to when the main body 26A of the bus bar 26 embedded in the lid portion 24 is spaced from the top surface and side surfaces of the lid portion 24 only approximately the same as the thickness of the main body 26A, it is possible to ensure good insulation between the positive electrode terminals 30A and between the negative electrode terminals 30B of adjacent battery cells 30, and between the positive electrode terminal 30A and negative electrode terminal 30B of the battery cell 30 itself.

[0057] In the first embodiment, adjacent battery cells 30 are connected to each other by the bus bar 26, but the battery cells 30 do not necessarily have to be adjacent to each other, and for example, every other battery cell 30 may be connected to each other. In either case, the layout restrictions imposed by the bus bar 26 can be alleviated compared to a configuration in which the lid portion 24 of the battery case 22 and the bus bar 26 are separate bodies.

[0058] Second Embodiment Next, a second embodiment will be described. Note that the same reference numerals are used to designate parts equivalent to those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0059] As shown in FIG. 7, the second embodiment differs from the first embodiment only in that a thermally conductive sheet 42 is provided as a thermally conductive member that contacts the upper surfaces of the positive electrode terminals 30A and negative electrode terminals 30B of the multiple battery cells 30 on the inner surface of the lid portion 24, other than at the locations where the connection terminals 26B are exposed.

[0060] The thermally conductive sheet 42 is a resin sheet having insulating and heat-dissipating properties, such as silicone resin or acrylic resin, and is formed in a generally rectangular flat plate shape large enough, when viewed from the bottom, to completely cover the main body 26A of each bus bar 26. By providing such a thermally conductive sheet 42 on the inner surface of the lid 24, the heat dissipation of each battery cell 30 can be improved compared to when the thermally conductive sheet 42 is not provided.

[0061] The thermally conductive sheet 42 may be provided so as to straddle the upper surfaces of the battery cells 30 arranged in the thickness direction, rather than on the inner surface of the lid portion 24. However, it is easier to assemble the battery pack 20 if the thermally conductive sheet 42 is provided on the inner surface of the lid portion 24. The thermal conductivity of the battery pack 20 according to the first and second embodiments is 0.4 to 398 [W / m K].

[0062] <Third embodiment> Next, a third embodiment will be described. Note that the same reference numerals are used to designate parts equivalent to those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0063] 8, the third embodiment differs from the first embodiment only in that a plurality of battery modules 44 are used instead of a plurality of battery cells 30. One battery module 44 is configured by electrically connecting a plurality of battery cells 30, and the illustrated battery module 44 is configured by electrically connecting two battery cells 30 via a bus bar 25.

[0064] 8 accommodates three battery modules 44 in the battery case 22, and the positive electrode terminal (not shown) and the negative electrode terminal (not shown) of each battery module 44 are electrically connected to the connection terminals 26B exposed from the inner surface of the lid portion 24 of each bus bar 26. In this way, even in the case of a battery pack 20 in which a plurality of battery modules 44 are accommodated in the battery case 22 instead of a plurality of battery cells 30, it is possible to achieve the same effects as those of the first embodiment.

[0065] <Fourth embodiment> Next, a fourth embodiment will be described. Note that the same reference numerals are used to designate parts equivalent to those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0066] As shown in Figure 9, the fourth embodiment differs from the first embodiment in that the lid portion 24 is composed of a lid portion main body 24A having an inner surface facing the multiple battery cells 30, and an exterior portion 24B that is molded from a resin material (e.g., polybutylene terephthalate) that is stronger than the resin material (e.g., polyamide) that molds the lid portion main body 24A, and covers all surfaces of the lid portion main body 24A except for the inner surface.

[0067] The bus bar 26, the detection wire 27, and the thermostat 28 are embedded in the lid body 24A, and a part of the detection wire 27 is drawn out through a hole 24C formed in the side wall of the exterior part 24B and electrically connected to the detector 40. The upper surface (outer surface) of the exterior part 24B is in full contact with the cooler 18 at a predetermined pressure.

[0068] In this way, when exterior part 24B of lid part 24 is made of a high-strength resin material that is stronger than lid part main body 24A, the rigidity of lid part 24 can be improved, and warping of lid part 24 can be more effectively suppressed or prevented. Therefore, even if the thickness of lid part 24 is reduced, insufficient strength and insufficient sealing performance of lid part 24 can be more effectively suppressed or prevented.

[0069] Instead of a high-strength resin material, exterior part 24B of lid part 24 may be made of a heat-resistant resin material that has higher heat resistance than lid main body 24A. Moreover, instead of a high-strength resin material, exterior part 24B of lid part 24 may be made of a metal or the like that has higher thermal conductivity than a resin layer formed therefrom.

[0070] Fifth Embodiment Next, a fifth embodiment will be described. Note that the same reference numerals are used to designate parts equivalent to those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0071] 10 , the fifth embodiment differs from the first embodiment in that the entire bus bar 26 is embedded in the lid portion 24 and in the shape of the electrode terminals of each battery cell 30. That is, in the fifth embodiment, not only the main body 26A of the bus bar 26 but also the connection terminal 26B is embedded in the lid portion 24. At least a portion of the connection terminal 26B is exposed to the inner surface of the lid portion 24 by a hole 24D of a predetermined depth formed in the lid portion 24.

[0072] On the other hand, the positive electrode terminal 30A and the negative electrode terminal 30B of each battery cell 30 are not provided with joining tabs 34, and each positive electrode terminal 30A and each negative electrode terminal 30B protrudes upward by a predetermined height. The positive electrode terminal 30A and each negative electrode terminal 30B of each battery cell 30 are inserted into the respective hole portions 24D and electrically connected to the respective connection terminals 26B. The fifth embodiment configured in this manner can also achieve the same effects as the first embodiment.

[0073] Furthermore, because the positive electrode terminals 30A and negative electrode terminals 30B of each battery cell 30 are inserted through the holes 24D, it is possible to improve the connectivity between the positive electrode terminals 30A and negative electrode terminals 30B and the bus bar 26, and it is also possible to improve the cooling performance of the positive electrode terminals 30A and negative electrode terminals 30B. Furthermore, the presence of the holes 24D in the lid 24 makes it possible to easily position the battery cells 30 when manufacturing the battery pack 20.

[0074] Sixth Embodiment Next, a sixth embodiment will be described. Note that the same reference numerals are used to designate parts equivalent to those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0075] 11, the sixth embodiment differs from the first embodiment in that the cooler 18 is disposed on either the left or right side in the vehicle width direction (on the right side in the illustrated example) with the surface that comes into contact with the outer surface of the lid portion 24 facing inward in the vehicle width direction. That is, in the sixth embodiment, the battery pack 20 is disposed horizontally with its lid portion 24 facing outward in the vehicle width direction (to the right side in the illustrated example).

[0076] The sixth embodiment having such a configuration can also achieve the same effects as the first embodiment. That is, since the bus bar 26 is still embedded in the lid portion 24 of the battery case 22, the outer surface of the lid portion 24 can be brought into direct contact with the cooler 18. Therefore, the cooling efficiency of the battery pack 20 can be improved compared to a configuration in which the lid portion 24 of the battery case 22 and the bus bar 26 are separate bodies.

[0077] Seventh Embodiment Finally, a seventh embodiment will be described. Note that the same reference numerals are used to designate parts equivalent to those in the first embodiment, and detailed descriptions (including common functions) will be omitted as appropriate.

[0078] As shown in FIG. 12(A), this seventh embodiment differs from the first embodiment in that a plurality of battery cells 50 (three are shown in the figure for simplicity) are arranged inside the battery case 22, each having a positive electrode terminal 50A and a negative electrode terminal 50B located at the center in the front-to-rear direction inside the battery case 22, and that a bus bar 46 that electrically connects the positive electrode terminals 50A and a bus bar 48 that electrically connects the negative electrode terminals 50B are each embedded independently (and have insulating properties) in the lid portion 24.

[0079] 12(B), bus bar 46 electrically connecting each positive electrode terminal 50A to each other has its main body 46A embedded in lid portion 24 without any gaps and without being exposed to the outside, and its connection terminal 46B exposed from the inner surface of lid portion 24. Similarly, bus bar 48 electrically connecting each negative electrode terminal 50B to each other has its main body 48A embedded in lid portion 24 without any gaps and without being exposed to the outside, at a position separated from bus bar 46, and its connection terminal 48B exposed from the inner surface of lid portion 24.

[0080] In the seventh embodiment, the battery cells 50 are arranged in a concentrated arrangement on one side in the front-rear direction inside the battery case 22, and therefore the bus bars 46 and 48 are respectively configured to be concentrated and embedded on the other side in the front-rear direction in the lid portion 24. In other words, the bus bars 46, 48 are embedded in approximately half of the area in the front-rear direction of the lid portion 24. Because the bus bars 46, 48 are configured to be embedded in the lid portion 24 in this way, it is possible to flexibly accommodate conductive circuits even with complex bus bar shapes.

[0081] The seventh embodiment having such a configuration can also achieve the same effects as the first embodiment. That is, because the bus bars 46, 48 are embedded in the lid portion 24 of the battery case 22, heat exchange with the cooler 18 can be performed efficiently. Therefore, the cooling efficiency of the battery pack 20 can be improved compared to a configuration in which the lid portion 24 of the battery case 22 and the bus bar 46 are separate bodies.

[0082] The battery pack 20 according to this embodiment has been described above with reference to the drawings. However, the battery pack 20 according to this embodiment is not limited to the one shown in the drawings, and the design can be appropriately modified without departing from the spirit of the present invention. For example, the battery module 44 in the third embodiment may be applied to the other embodiments. Furthermore, the detector 40 may be disposed inside the battery case 22.

[0083] Furthermore, each battery cell 30 in the first to fourth and sixth embodiments may not be provided with a joining tab 34. That is, the positive electrode terminal 30A and the negative electrode terminal 30B of each battery cell 30 may be configured to directly contact and electrically connect to the connection terminal 26B of the bus bar 26, respectively.

[0084] Alternatively, a battery pack may be formed in which a plurality of battery cells (not shown), each having a positive electrode terminal and a negative electrode terminal spaced apart from each other at the front and rear sides, are housed in the battery case 22. In this case, the bus bar 26 may be embedded in the bottom wall of the battery case 22 in the same manner, and the cooler 18 may also be installed so as to contact the lower surface of the bottom wall of the battery case 22 (for example, on the upper surface of the flat plate portion 16A of the support base 16).

[0085] Furthermore, although the battery cell 30 according to this embodiment has the positive electrode terminal 30A and the negative electrode terminal 30B spaced apart from each other on one surface (top surface), this is not limited to this. For example, as shown in Fig. 11, in the case of a horizontally placed battery pack 20, a battery cell (not shown) may have the positive electrode terminal on one surface and the negative electrode terminal on the other surface opposite thereto.

[0086] In this case, the bus bar 26 may be embedded in the wall of the battery case 22 opposite the lid 24 (the wall corresponding to the bottom wall of the battery case 22 in the first embodiment), and the cooler 18 may be additionally installed on the left side of the drawing so as to contact the outer surface of the wall. In this case, the cooler 18 may also be installed so as to contact the upper surface of the lid 24, etc. [Explanation of symbols]

[0087] 10 vehicles 18 Cooler 20 Battery pack 22 Battery case 24 Lid 24A Lid body 24B Exterior part 24D hole 26 Busbar 26A Main body 26B connection terminal 30 battery cells 30A electrode terminal 30B Electrode terminal 34 Joint tab 42 Thermally conductive sheet (thermally conductive material) 44 Battery Module

Claims

1. a plurality of battery cells or a plurality of battery modules each having a positive electrode terminal and a negative electrode terminal; a battery case that houses the plurality of battery cells or the plurality of battery modules; a lid portion made of an insulator and provided for the battery case; a bus bar including: a main body portion embedded in the lid portion; and connection terminals provided at an end of the main body portion, exposed from an inner surface of the lid portion facing the plurality of battery cells or the plurality of battery modules, and electrically connected to positive and negative electrode terminals of the plurality of battery cells or the plurality of battery modules; Equipped with The battery pack has an outer surface of the lid in contact with a cooler.

2. 2. The battery pack according to claim 1, wherein the connection terminals of the bus bar are electrically connected to the positive electrode terminal and the negative electrode terminal via joining tabs, respectively, and are formed to a size such that they do not protrude from the joining tabs.

3. 3. The battery pack according to claim 1, wherein the body portion of the bus bar embedded in the lid is spaced from the outer surface and the side surface of the lid by at least twice the thickness of the body portion.

4. 3. The battery pack according to claim 1, wherein a heat conductive member is provided on the inner surface of the lid portion at a location other than where the connection terminals are exposed, the heat conductive member being in contact with the plurality of battery cells or the plurality of battery modules.

5. The lid portion is a lid body having an inner surface facing the plurality of battery cells or the plurality of battery modules; 3. The battery pack according to claim 1, further comprising an exterior portion formed of a high-strength material stronger than the lid body and covering the lid body except for the inner surface.

6. a plurality of battery cells or a plurality of battery modules each having a positive electrode terminal and a negative electrode terminal; a battery case that houses the plurality of battery cells or the plurality of battery modules; a lid portion made of an insulator and provided for the battery case; a bus bar including a main body embedded in the lid and a connection terminal provided at an end of the main body and embedded in the lid, the connection terminal being at least partially exposed through a hole formed in the lid; Equipped with positive electrode terminals and negative electrode terminals of the plurality of battery cells or the plurality of battery modules are inserted into the hole portions and electrically connected to the connection terminals; The battery pack has an outer surface of the lid in contact with a cooler.

7. 7. The battery pack according to claim 1, wherein the outer surface of the lid is in contact with the cooler over the entire surface.

Images