Electric vehicles

Abstract

An electric vehicle according to the present invention comprises: an electric motor that generates a driving force for travel; a battery; and an inverter that converts DC power generated by the battery to AC power and supplies the AC power to the electric motor. The electric vehicle further comprises: a battery case; a cooling jacket provided on at least on of the electric motor and the inverter; and a pump. The battery case is provided with: an accommodation space in which the battery is accommodated; a liquid-tight space separated from the accommodation space; and a refrigerant entrance and refrigerant exit that communicate with the liquid-tight space. The battery case has an air-cooled section that demarcates the liquid-tight space and is exposed to traveling wind. The pump causes the refrigerant to flow within a refrigerant flow path, passing from the liquid-tight space through the refrigerant exit, the cooling jacket, and the refrigerant entrance in that order, and returning to the liquid-tight space.

Description

Related Applications

[0001] This application claims priority to Japanese Patent Application No. 2021-125523 filed on July 30, 2021, the entire contents of which are incorporated herein by reference. [Technical field]

[0002] The present invention relates to an electric vehicle. [Background technology]

[0003] The saddle-type electric vehicle described in Patent Document 1 includes a frame, a front fork supported by a front end of the frame, a front wheel supported by the front fork, a rear unit supported by a rear lower part of the frame, and a rear wheel supported by the rear unit. The saddle-type electric vehicle includes an electric drive motor supported by the frame and driving the rear wheel, a seat provided on the rear upper part of the frame, and a battery disposed below the seat and supplying power to the drive motor. The battery is housed in a battery case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-66289 Summary of the Invention [Problem to be solved by the invention]

[0005] Electric vehicles are required to have an increased driving range, and to achieve this, it is necessary to increase the capacity of the battery. Accordingly, the battery case may become a large component that occupies a large proportion of the entire electric vehicle. On the other hand, electric components such as an electric motor and an inverter, which are essential in an electric vehicle other than the battery, must be operated at or below their operating limit temperature, so a cooling structure for the electric components other than the battery may be required depending on the amount of heat generated by the electric components. Depending on layout constraints in an electric vehicle, it may be difficult to design the cooling structure to be arranged in addition to a large battery case. Even if this is possible, it is not necessarily possible to arrange a large radiator as the cooling structure in a position advantageous for cooling.

[0006] An embodiment of the present invention provides an electric vehicle in which a new cooling structure can be constructed for electric components other than the battery. [Means for solving the problem]

[0007] One embodiment of the present invention provides an electric vehicle including an electric motor that generates a driving force for running the electric vehicle, a battery, and an inverter that converts DC power generated by the battery into AC power and supplies the AC power to the electric motor. The electric vehicle further includes a battery case, a cooling jacket provided on at least one of the electric motor and the inverter, and a pump. The battery case is provided with an accommodation space that accommodates the battery, a liquid-tight space isolated from the accommodation space, and a refrigerant inlet and a refrigerant outlet that communicate with the liquid-tight space. The battery case has an air-cooling section that partitions the liquid-tight space and is exposed to a running wind. The pump causes a refrigerant to flow in a refrigerant flow path that passes from the liquid-tight space through the refrigerant outlet, the cooling jacket, and the refrigerant inlet in this order and returns to the liquid-tight space.

[0008] According to this configuration, the electric motor and the inverter are electrical components other than the battery. When the pump is operated, the refrigerant returns from the liquid-tight space provided in the battery case to the liquid-tight space by passing through the refrigerant outlet, the cooling jacket, and the refrigerant inlet in this order. The liquid-tight space is partitioned by an air-cooling section exposed to the running wind in the battery case. Therefore, the refrigerant is cooled by the air-cooling section when passing through the liquid-tight space, and reaches the cooling jacket in a relatively low temperature state after flowing out from the refrigerant outlet. As a result, the electrical components provided with the cooling jacket are cooled by heat exchange with the refrigerant. The refrigerant that has passed through the cooling jacket becomes relatively hot due to heat exchange with the electrical components, but flows into the liquid-tight space from the refrigerant inlet and is cooled again by the air-cooling section. Therefore, the temperature of the refrigerant flowing into the liquid-tight space from the refrigerant inlet is higher than the temperature of the refrigerant flowing out from the refrigerant outlet.

[0009] In this way, the cooling jacket, the battery case, the pump, and the refrigerant flow path constitute a cooling structure for the electrical components other than the battery. Therefore, by utilizing the battery case, a new cooling structure for the electrical components can be constructed.

[0010] In one embodiment of the present invention, the battery case includes an inner case that covers at least a part of an outer surface of the battery, and an outer case that is provided with the air-cooling unit and covers at least a part of the outer surface of the inner case. In this case, the liquid-tight space is defined between the inner case and the outer case. With this configuration, the battery case has a double structure, and the space between the inner case and the outer case can be effectively used as a liquid-tight space.

[0011] In this case, the outer surface of the inner case may include a plurality of surfaces exposed to the liquid-tight space.

[0012] In one embodiment of the present invention, the air-cooling portion may be provided on a lower surface of the outer case.

[0013] In one embodiment of the present invention, a battery liquid-tight space for cooling battery cells is provided inside the battery. The inner case includes a first inner case that covers at least a portion of an outer surface of the battery in the accommodation space, and a second inner case that covers at least a portion of the first inner case to define the liquid-tight space between the first inner case and the outer case. The electric vehicle further includes a battery radiator, and a battery pump that causes refrigerant to flow in a battery refrigerant flow path that passes from the battery liquid-tight space through the battery radiator and returns to the battery liquid-tight space.

[0014] According to this configuration, when the battery pump is operated, the refrigerant for cooling the battery cells returns from the battery liquid-tight space provided inside the battery to the battery liquid-tight space through the battery radiator. Therefore, the refrigerant is cooled when passing through the battery radiator, and returns to the battery liquid-tight space at a relatively low temperature to cool the battery cells in the battery. In this way, the battery cells can be cooled by a cooling structure separate from the cooling structure for electrical components other than the battery.

[0015] In one embodiment of the present invention, a battery liquid-tight space is defined between the inner case and the battery. The electric vehicle further includes a battery radiator and a battery pump that causes refrigerant to flow in a battery refrigerant flow path that runs from the battery liquid-tight space through the battery radiator and returns to the battery liquid-tight space.

[0016] According to this configuration, when the battery pump is operated, the coolant for cooling the battery passes from the liquid-tight space for the battery between the inner case and the battery through the radiator for the battery and returns to the liquid-tight space for the battery. Therefore, the coolant is cooled when passing through the radiator for the battery, and returns to the liquid-tight space for the battery at a relatively low temperature to cool the battery. In this way, the battery can be cooled by a cooling structure separate from the cooling structure for the electrical components other than the battery.

[0017] In one embodiment of the present invention, a radiator is not attached to the coolant flow path. With this configuration, a radiator is omitted in the cooling structure for electrical components other than the battery, so that the number of components in the cooling structure can be reduced.

[0018] In one embodiment of the present invention, the electric vehicle further includes a radiator that cools the refrigerant flowing in the refrigerant flow path from the refrigerant outlet to the cooling jacket.

[0019] According to this configuration, the cooling structure for the electrical components other than the battery includes a radiator. Therefore, the refrigerant is cooled by the air-cooling portion of the battery case when passing through the liquid-tight space, and then further cooled by the radiator before passing through the cooling jacket. This allows the electrical components provided with the cooling jacket to be effectively cooled by the refrigerant. In addition, since the air-cooling portion of the battery case has the function of cooling the refrigerant, a small radiator is sufficient.

[0020] In one embodiment of the present invention, the radiator is disposed forward of the battery case, whereby the radiator can be disposed in a position where it is easily exposed to wind while the vehicle is running, thereby improving the efficiency with which the radiator cools the refrigerant.

[0021] In one embodiment of the present invention, a radiator is not installed. According to this configuration, the electric vehicle does not require a radiator at all, so that the number of parts can be reduced.

[0022] In one embodiment of the present invention, the cooling jacket includes a motor cooling jacket provided on the electric motor and an inverter cooling jacket provided on the inverter. The inverter cooling jacket is located upstream from the refrigerant inlet more than the motor cooling jacket in the flow direction of the refrigerant flowing through the refrigerant flow path. In other words, the refrigerant outlet, the inverter cooling jacket, the motor cooling jacket, and the refrigerant inlet are arranged in this order in the refrigerant flow path in the flow direction of the refrigerant. This allows the refrigerant flowing out from the refrigerant outlet to pass through the inverter cooling jacket and then through the motor cooling jacket.

[0023] Generally, the operating temperature of an inverter is lower than the operating temperature of an electric motor, so even if a refrigerant is passed through the inverter cooling jacket to cool the inverter first, the temperature of the refrigerant after passing through the inverter cooling jacket is lower than the operating temperature of the electric motor, and so the refrigerant can also be used to cool the electric motor by passing through the motor cooling jacket.

[0024] In one embodiment of the present invention, the air-cooling section may include a heat sink.

[0025] In one embodiment of the present invention, the air-cooling unit may be detachable from the battery case.

[0026] In one embodiment of the present invention, the electric vehicle is a saddle-ride type electric vehicle including front and rear wheels. According to this configuration, since the battery case can be used as a cooling structure for electric components other than the battery, the cooling structure can be adopted even in a saddle-ride type electric vehicle with relatively large layout restrictions. In a saddle-ride type electric vehicle, the battery case can be actively exposed to the outside of the saddle-ride type electric vehicle, so that the air-cooled part of the battery case can be efficiently exposed to the running wind. Furthermore, in a saddle-ride type electric vehicle adopting the cooling structure, a radiator can be omitted. Even if a radiator is provided, a small radiator is sufficient. This allows the saddle-ride type electric vehicle to be made smaller. By omitting or reducing the size of the radiator, a large-capacity battery can be mounted, so that the cruising distance of the saddle-ride type electric vehicle can be increased.

[0027] In one embodiment of the present invention, the battery case is disposed forward of the electric motor and the inverter in the region between the front wheels and the rear wheels. With this configuration, the air-cooled portion of the battery case can be efficiently exposed to the running wind. In this case, the electric motor may be disposed rearward of the inverter.

[0028] The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0029] [Figure 1] 1 is a left side view of an electric vehicle according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a left side view of a main portion of the electric vehicle. [Diagram 3] 1 is a schematic diagram for explaining a cooling structure according to a first embodiment of the present invention in an electric vehicle. [Figure 4] FIG. 6 is a schematic diagram for explaining a cooling structure according to a second embodiment. [Diagram 5] FIG. 11 is a schematic diagram for explaining a cooling structure according to a third embodiment. [Figure 6] FIG. 13 is a schematic cross-sectional view of a battery case in a cooling structure according to a fourth embodiment. [Figure 7] FIG. 13 is a schematic cross-sectional view of a battery case in a cooling structure according to a fifth embodiment. [Figure 8] FIG. 13 is a schematic cross-sectional view of a battery case in a cooling structure according to a sixth embodiment. [Figure 9] FIG. 13 is a schematic cross-sectional view of a battery case in a cooling structure according to a seventh embodiment. [Figure 10] FIG. 13 is a schematic diagram for explaining a cooling structure according to an eighth embodiment. [Figure 11] FIG. 13 is a schematic diagram for explaining a cooling structure according to a ninth embodiment. [Figure 12] FIG. 23 is a schematic diagram for explaining a cooling structure according to a tenth embodiment. [Figure 13] FIG. 23 is a schematic diagram for explaining a cooling structure according to an eleventh embodiment. [Figure 14] FIG. 23 is a schematic cross-sectional view of a battery case in a cooling structure according to an eleventh embodiment. [Figure 15] FIG. 23 is a schematic diagram for explaining a cooling structure according to a twelfth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] An electric vehicle 1 according to one embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, the front-rear direction, left-right direction, and up-down direction are directions defined based on the viewpoint of a rider operating the electric vehicle 1. The left-right direction is the vehicle width direction of the electric vehicle 1. The description will be based on a state in which the electric vehicle 1 is placed on a horizontal plane.

[0031] Fig. 1 is a left side view of an electric vehicle 1. One example of the electric vehicle 1 is a saddle-ride type electric vehicle including a front wheel 2 and a rear wheel 3, more specifically an electric two-wheeler, but the number of each of the front wheel 2 and the rear wheel 3 may be one or more, and each of the front wheel 2 and the rear wheel 3 may include an endless track such as a crawler instead of a tire. The electric vehicle 1 may be an electric vehicle other than a saddle-ride type electric vehicle. Examples of the form of an electric vehicle other than a saddle-ride type electric vehicle include a form in which multiple seats are arranged side by side in the left-right direction.

[0032] The electric vehicle 1 includes a front fork 4 that rotatably supports the front wheel 2, a handlebar 5 attached to an upper end of the front fork 4, a swing arm 6 that rotatably supports the rear wheel 3, and a frame 7 that supports the front fork 4 and the swing arm 6. The front fork 4 is rotatable in the left-right direction, and the swing arm 6 is swingable in the up-down direction. A front fender 8 that covers an upper part of the front wheel 2 is provided on the front fork 4. A rear fender 9 that covers an upper part of the rear wheel 3 is supported by the frame 7.

[0033] The electric vehicle 1 includes a stand 10 attached to the frame 7, a rear shock 11 connecting the swing arm 6 and the frame 7, a cowling 12 covering almost the entire frame 7, and a seat 13 supported by the frame 7 behind the handlebars 5. The cowling 12 may be a single component or an assembly of multiple components. A gap (not shown) is formed between the frame 7 and the cowling 12 into which wind can enter when the electric vehicle 1 is traveling.

[0034] A headlight 14 is exposed at the front of the cowling 12. A windscreen 15 that covers the handlebars 5 from the front is provided at the front of the cowling 12. A brake light 16 is exposed at the rear of the cowling 12. A rider sits on the seat 13 and operates the handlebars 5 to steer the electric vehicle 1. A tandem step 17 and a grab bar 18 for two-seater use may be provided at the rear of the cowling 12.

[0035] 2 is a left side view of essential parts of the electric vehicle 1 with the swing arm 6, front fender 8, rear fender 9, stand 10, rear shock 11, cowling 12, seat 13, etc. omitted. The frame 7 has a pair of left and right down tubes 7A, an upper tube 7B disposed above the down tubes 7A and extending in the front-to-rear direction, a front support portion 7C rising upward from the front end of the upper tube 7B and supporting the front fork 4, and a seat rail 7D extending rearward from the rear end of the upper tube 7B.

[0036] The down tubes 7A are disposed between the front wheel 2 and the rear wheel 3 and extend in the front-to-rear direction. A front end 7AA of each down tube 7A curves and extends upward substantially vertically and is connected to a front end of the upper tube 7B. A rear end 7AB of each down tube 7A curves upward and extends diagonally rearward and is connected to the rear end of the upper tube 7B. A bracket 7AC protruding rearward is provided on the rear end 7AB of at least one of the down tubes 7A.

[0037] The electric vehicle 1 includes an electric motor 20 fixed to a bracket 7AC of a down tube 7A, a battery unit 21 disposed between a pair of left and right down tubes 7A, and an inverter 22 fixed to a rear end portion 7AB of at least one of the down tubes 7A. The cowling 12 may have a protective cover 12A that covers the bracket 7AC and the electric motor 20 from the sides (see FIG. 1).

[0038] An example of the electric motor 20 is a three-phase AC motor. The electric motor 20 has an output shaft 20A extending in the left-right direction. A sprocket 23 is fixed to the rear wheel 3. The output shaft 20A and the sprocket 23 are connected by a chain 24. When the electric motor 20 is operated to generate driving force, the output shaft 20A rotates and the driving force of the electric motor 20 is transmitted to the sprocket 23 by the chain 24, thereby rotating the rear wheel 3. This causes the electric vehicle 1 to run. A pulley may be used instead of the sprocket 23, and a belt may be used instead of the chain 24.

[0039] The battery unit 21 is disposed in an area X between the front wheels 2 and the rear wheels 3. The battery unit 21 includes a box-shaped battery case 30 that forms an outer shell thereof, and a battery 31 disposed within the battery case 30.

[0040] The battery case 30 is long in the front-rear direction, occupies most of the area X, and is disposed between a pair of down tubes 7A and fixed to each down tube 7A. The battery case 30 is formed of a material with a large heat capacity, such as aluminum. The battery case 30 is exposed to the wind flowing through the gap between the frame 7 and the cowling 12. The cowling 12 may be provided with an inlet or guide (not shown) for guiding the wind to the battery case 30. The lower part of the battery case 30 may be exposed to the ground without being covered by the cowling 12.

[0041] The battery 31 is composed of one or more battery cells 31A and a box-shaped package 31B that houses the battery cells 31A (see Figs. 13 and 14 described later). The outer surface of the package 31B is the outer surface 31C of the battery 31 (see Fig. 3 described later). One example of the battery 31 is a lithium ion battery.

[0042] The inverter 22 converts DC power generated by the battery 31 into AC power and supplies it to the electric motor 20. This causes the electric motor 20 to operate. The inverter 22 may be provided in a motor control unit (MCU) that controls the electric motor 20. In the area X between the front wheels 2 and the rear wheels 3, the electric motor 20 is disposed rearward of the inverter 22. The electric motor 20 and the inverter 22 are electrical components other than the battery 31, and tend to heat up and cool down more easily than the battery 31. Meanwhile, the electric motor 20 and the inverter 22 have a higher operating temperature than the battery 31, and the electric motor 20 has a higher operating temperature than the inverter 22. The operating temperature here refers to the normal temperature of each component in an operating state, and is a temperature equal to or lower than the maximum allowable temperature of each component in its operating state.

[0043] The electric vehicle 1 includes a cooling structure 32 for cooling at least one of the electric motor 20 and the inverter 22. Various embodiments of the cooling structure 32 will be described below. Fig. 3 is a schematic diagram for explaining the cooling structure 32 according to a first embodiment.

[0044] Common to the first embodiment and all subsequent embodiments, the cooling structure 32 includes a battery case 30 and a hollow cooling jacket 33 provided on at least one of the electric motor 20 and the inverter 22. The battery case 30 is disposed forward of the electric motor 20 and the inverter 22 in the region X between the front wheels 2 and the rear wheels 3 (see FIG. 2).

[0045] The battery case 30 is provided with an accommodation space 30A that accommodates the battery 31, a liquid-tight space 30B that is isolated from the accommodation space 30A, and a refrigerant inlet 30C and a refrigerant outlet 30D that communicate with the liquid-tight space 30B. The battery case 30 has an air-cooling section 30E that partitions the liquid-tight space 30B and is exposed to the running wind. The air-cooling section 30E includes a heat sink formed of one or more fins 30F. The electric motor 20 and the inverter 22 are electrically connected by three electric wires 34 corresponding to AC power. The inverter 22 and the battery 31 are electrically connected by two electric wires 35 corresponding to DC power.

[0046] Common to all the embodiments, the cooling structure 32 further includes a refrigerant flow path 36, a tank 37 connected to the refrigerant flow path 36, and a pump 38 that causes a refrigerant such as a cooling liquid stored in the tank 37 to flow in the refrigerant flow path 36. The refrigerant flow path 36 is a flow path for flowing the refrigerant, and the liquid-tight space 30B of the battery case 30, the internal space of the cooling jacket 33, and the internal space of the pump 38 are parts of the refrigerant flow path 36. The cooling structure 32 also includes a pipe 39 that constitutes the remaining part of the refrigerant flow path 36. The tank 37 is provided to adjust the pressure of the refrigerant flowing through the refrigerant flow path 36. The tank 37 may be interposed in the middle of the refrigerant flow path 36 (see FIG. 3, etc.), or may be disposed independently of the refrigerant flow path 36 and connected to the refrigerant flow path 36 via a pipe 44 (see FIG. 11, etc.). When the tank 37 is interposed in the middle of the refrigerant flow path 36, the internal space of the tank 37 constitutes a part of the refrigerant flow path 36.

[0047] The pump 38 may be a mechanical pump operated by the driving force of the electric motor 20, or may be an electric pump operated by the electric power from the battery 31. When the pump 38 is operated, the refrigerant circulates in the refrigerant flow passage 36 so that the refrigerant leaves the liquid-tight space 30B through the refrigerant outlet 30D, passes through the pump 38, the cooling jacket 33, and the refrigerant inlet 30C in this order, and returns to the liquid-tight space 30B (see the refrigerant flow direction Y1). As a result, the refrigerant cooled by the air-cooling section 30E while passing through the liquid-tight space 30B flows out of the air-cooling section 30E and reaches the cooling jacket 33 in a relatively low temperature state. Therefore, at least one of the electric motor 20 and the inverter 22, which are electric components provided with the cooling jacket 33, is cooled by heat exchange with the refrigerant. The refrigerant that passes through the cooling jacket 33 becomes relatively hot due to heat exchange with the electric components, but when it returns to the liquid-tight space 30B from the refrigerant inlet 30C, it is cooled again by the air-cooling section 30E. Therefore, the temperature T1 of the coolant flowing from the coolant inlet 30C into the liquid-tight space 30B is higher than the temperature T2 of the coolant flowing out from the coolant outlet 30D.

[0048] In this way, the cooling jacket 33, the battery case 30, the pump 38, and the refrigerant flow path 36 constitute a cooling structure 32 for at least one of the electric motor 20 and the inverter 22, which are electrical components other than the battery 31. Therefore, by utilizing the battery case 30, a new cooling structure 32 for the electrical component can be constructed.

[0049] In particular, even if the electric vehicle 1 is a saddle-ride type electric vehicle with relatively large layout constraints, the cooling structure 32 can be adopted. In the case of a saddle-ride type electric vehicle, the battery case 30 can be disposed so as to be actively exposed to the outside of the saddle-ride type electric vehicle, so that the air-cooling section 30E of the battery case 30 can be efficiently exposed to the traveling wind. And, since the battery case 30 is disposed forward of the electric motor 20 and the inverter 22, the air-cooling section 30E can be more efficiently exposed to the traveling wind. Also, in the case of a saddle-ride type electric vehicle employing the cooling structure 32, a radiator can be omitted. Even if a radiator is provided, the radiator can be small. This allows the saddle-ride type electric vehicle to be made smaller. By omitting or reducing the size of the radiator, a large-capacity battery 31 can be mounted, so that the cruising distance of the saddle-ride type electric vehicle can be increased.

[0050] In the first embodiment, it is assumed that the output of the electric motor 20 is relatively low. In this case, the heat generation amounts of the electric motor 20 and the inverter 22 are relatively small. In the cooling structure 32 according to the first embodiment, the cooling jacket 33 is provided only on the electric motor 20. Hereinafter, the cooling jacket 33 provided on the electric motor 20 is referred to as a motor cooling jacket 33A, and the cooling jacket 33 provided on the inverter 22 is referred to as an inverter cooling jacket 33B (see FIG. 5 described later). In the first embodiment, the inverter 22, which is not provided with the cooling jacket 33, is cooled by the surrounding air.

[0051] In the first embodiment, the electric vehicle 1 is not provided with a radiator. That is, the electric vehicle 1 does not include any radiator, so that the number of parts can be reduced. The battery case 30 includes an inner case 40 that covers at least a part of the outer surface 31C of the battery 31, and an outer case 41 that is provided with an air-cooling section 30E and covers at least a part of the outer surface 40A of the inner case 40. An air-insulating layer A is formed between the outer surface 31C of the battery 31 and the inner case 40. The liquid-tight space 30B is partitioned between the inner case 40 and the outer case 41. According to this configuration, the battery case 30 has a double structure, and the space between the inner case 40 and the outer case 41 can be effectively used as the liquid-tight space 30B. The outer surface 40A of the inner case 40 includes a plurality of surfaces exposed to the liquid-tight space 30B.

[0052] In FIG. 3, as an example, the inner case 40 is in a box shape that is one size larger than the battery 31, and covers all of the outer surfaces 31C of the battery 31. The internal space of the inner case 40 is the storage space 30A that stores the battery 31 in the battery case 30. The storage space 30A and the liquid-tight space 30B are isolated from each other by the inner case 40 therebetween. The outer case 41 is in a box shape that is one size larger than the inner case 40, and covers all of the outer surfaces 40A of the inner case 40. Of the outer surfaces 40A, at least the upper surface 40AA, the lower surface 40AB, and the side surface 40AC are exposed to the liquid-tight space 30B.

[0053] The air-cooling section 30E of the battery case 30 is provided on the underside 41AA, which is a part of the outer surface 41A of the outer case 41. In this case, if the air-cooling section 30E is exposed downward from the cowling 12 (see FIG. 1), the air-cooling section 30E is likely to be exposed to the running wind flowing along the ground, and therefore the refrigerant passing through the liquid-tight space 30B can be effectively cooled by the air-cooling section 30E.

[0054] FIG. 4 is a schematic diagram for explaining a cooling structure 32 according to the second embodiment. Hereinafter, the same parts as those described in the first embodiment are given the same numbers, and detailed explanations of those parts are omitted. In the battery case 30 of the second embodiment, the inner case 40 is omitted, and the liquid-tight space 30B is formed in the wall of the outer case 41. Hatching in FIG. 4 shows a cross section of the outer case 41. In FIG. 4, as an example, the liquid-tight space 30B passes through the thickness of the bottom wall 41B of the outer case 41, and the liquid-tight space 30B is formed only in the bottom wall 41B. The accommodation space 30A and the liquid-tight space 30B are isolated from each other by a portion 41BA of the bottom wall 41B above the liquid-tight space 30B. The bottom surface of the bottom wall 41B is the bottom surface 41AA of the outer case 41.

[0055] The third embodiment shown in FIG. 5 is a modified example of the first embodiment (see FIG. 3), and in a cooling structure 32 according to the third embodiment, a cooling jacket 33 is provided only for the inverter 22 as an inverter cooling jacket 33B. Therefore, in the third embodiment, the electric motor 20, which is not provided with the cooling jacket 33, is cooled by the surrounding air. If the appropriate operating temperature of the electric motor 20 can be maintained by only such air cooling, the cooling jacket for the electric motor 20 can be omitted, as in this third embodiment. On the other hand, when the operating temperature of the inverter 22 is lower than the temperature of the outside air, for example, and cooling by only the surrounding air is insufficient to cool the inverter 22, the cooling jacket for the inverter 22 is provided. Ket It is preferable to provide 33B.

[0056] FIG. 6 is a schematic cross-sectional view of the battery case 30 in the cooling structure 32 according to the fourth embodiment. The outer case 41 may be a cover-like case that covers only a part of the outer surface 40A of the inner case 40, instead of the box-like case described above. In the fourth embodiment, the cover-like outer case 41 provided with the air-cooling unit 30E is provided so as to cover each of the multiple surfaces on the outer surface 40A of the inner case 40. Specifically, in FIG. 6, the outer case 41 is provided on each of the upper surface 40AA, the lower surface 40AB, and the side surface 40AC on the outer surface 40A of the inner case 40. A liquid-tight space 30B is defined between each of the upper surface 40AA, the lower surface 40AB, and the side surface 40AC and the corresponding outer case 41. These liquid-tight spaces 30B may be connected to the refrigerant inlet 30C after joining together, or may be connected to the refrigerant inlet 30C separately. The same applies to the refrigerant outlet 30D.

[0057] 7, only one cover-like outer case 41 may be provided to cover only one surface of the outer surface 40A of the inner case 40. The outer case 41 shown in FIG. 7 covers the lower surface 40AB of the inner case 40 from below, and a liquid-tight space 30B is defined between the lower surface 40AB and the outer case 41.

[0058] The air-cooling unit 30E may be a separate part from the battery case 30 as in the sixth embodiment shown in FIG. 8. In this case, the air-cooling unit 30E may be detachable from the inner case 40 of the battery case 30 together with the outer case 41. As an example, the outer case 41 is connected to the inner case 40 by a fastening member such as a bolt, and the air-cooling unit 30E can be detached from the inner case 40 by an operator loosening the fastening member. The same applies to the seventh embodiment shown in FIG. 9 in which the outer case 41 covers only a part of the outer surface 40A of the inner case 40 (the lower surface 40AB in FIG. 9). The detachable air-cooling unit 30E has at least a liquid-tight space 30B, but may also have at least one of a refrigerant inlet 30C and a refrigerant outlet 30D.

[0059] In the cooling structure 32 according to the eighth embodiment shown in FIG. 10, the cooling jacket 33 is provided for each of the electric motor 20 and the inverter 22. That is, the cooling jacket 33 includes both the motor cooling jacket 33A and the inverter cooling jacket 33B. In this case, with respect to the flow direction Y1 of the refrigerant flowing through the refrigerant flow passage 36, the inverter cooling jacket 33B is located upstream from the refrigerant inlet 30C more than the motor cooling jacket 33A. That is, in the refrigerant flow passage 36, the refrigerant outlet 30D, the inverter cooling jacket 33B, the motor cooling jacket 33A, and the refrigerant inlet 30C are arranged in this order with respect to the refrigerant flow direction Y1. As a result, the refrigerant flowing out from the refrigerant outlet 30D passes through the inverter cooling jacket 33B and then passes through the motor cooling jacket 33A.

[0060] As described above, the operating temperature of the inverter 22 is lower than the operating temperature of the electric motor 20. Therefore, according to the configuration of the eighth embodiment, even if the refrigerant is caused to flow through the inverter cooling jacket 33B to cool the inverter 22 first, the temperature of the refrigerant after passing through the inverter cooling jacket 33B is lower than the operating temperature of the electric motor 20. Therefore, by subsequently flowing this refrigerant through the motor cooling jacket 33A, it can also be used to cool the electric motor 20.

[0061] The cooling structure 32 according to the ninth embodiment shown in FIG. 11 is a modified example of the eighth embodiment, and further includes a radiator 42 located between the refrigerant outlet 30D and the pump 38 in the refrigerant flow path 36. The radiator 42 cools the refrigerant flowing from the refrigerant outlet 30D to the cooling jacket 33 in the refrigerant flow path 36. According to this configuration, the refrigerant is cooled by the air-cooling section 30E of the battery case 30 when passing through the liquid-tight space 30B, and then further cooled by the radiator 42 before passing through the cooling jacket 33. This allows the electric components (both the electric motor 20 and the inverter 22 in FIG. 11) on which the cooling jacket 33 is provided to be effectively cooled. In addition, since the air-cooling section 30E of the battery case 30 has the function of cooling the refrigerant, the radiator 42 can be small. A tank 37 arranged independently of the refrigerant flow path 36 is connected to the radiator 42 via a pipe 44, and the refrigerant travels between the tank 37 and the radiator 42.

[0062] The radiator 42 is disposed forward of the battery case 30 (see FIG. 2). This allows the radiator 42 to be disposed in a position where it is easily exposed to the wind while the vehicle is running, thereby improving the efficiency with which the radiator 42 cools the refrigerant.

[0063] The tenth embodiment shown in Fig. 12 is a modification of the ninth embodiment, and assumes a case in which the output of the electric motor 20 is even higher than in the previous embodiments. In this case, the heat generation amounts of both the electric motor 20 and the inverter 22 are relatively large, and the heat generation amount of the battery 31 is also large. Therefore, the electric vehicle 1 according to the tenth embodiment includes a cooling structure 43 for the battery 31 in addition to the above-mentioned cooling structure 32.

[0064] In relation to the cooling structure 43, a battery liquid-tight space 45 is defined between the inner case 40 and the battery 31 in the battery case 30, instead of the above-mentioned air-based insulating layer A (see FIG. 3). The cooling structure 43 further includes a battery refrigerant flow path 46, a battery pressure adjustment tank 47 provided for adjusting the pressure of the refrigerant flowing through the battery refrigerant flow path 46, and a battery pump 48 that causes the refrigerant accumulated in the battery pressure adjustment tank 47 to flow through the battery refrigerant flow path 46.

[0065] As described above, the operating temperature of the battery 31 is lower than the operating temperatures of the electric motor 20 and the inverter 22. More specifically, the upper limit of the operating temperature of the battery 31 is lower than the normal operating temperatures of the electric motor 20 and the inverter 22. Therefore, the temperature of the coolant for cooling the battery 31 used in the cooling structure 43 is lower than the temperature of the coolant for cooling the electric motor 20 and the inverter 22 used in the cooling structure 32. In other words, the battery 31 and the electric motor 20 and the inverter 22 have different requirements for the coolant temperature. Therefore, as in the tenth embodiment, the cooling structure 43, which is the cooling system for the battery 31, may be provided separately from the cooling structure 32, which is the cooling system for the electric motor 20 and the inverter 22.

[0066] The battery coolant flow path 46 is a flow path for flowing the coolant, and the battery liquid-tight space 45 and the internal space of the battery pump 48 are part of the battery coolant flow path 46. The cooling structure 43 also includes a battery radiator 49 interposed between the battery liquid-tight space 45 and the battery pump 48. The internal space of the battery radiator 49 is also part of the battery coolant flow path 46. The cooling structure 43 also includes a pipe 50 constituting the remaining part of the battery coolant flow path 46. In the tenth embodiment, the battery pressure adjustment tank 47 is connected to the battery radiator 49 via a pipe 54, and is thus arranged independently from the battery coolant flow path 46, and the coolant travels between the battery pressure adjustment tank 47 and the battery radiator 49. Alternatively, the battery pressure adjustment tank 47 may be interposed in the middle of the battery coolant flow path 46, and in that case, the internal space of the battery pressure adjustment tank 47 constitutes part of the battery coolant flow path 46.

[0067] The battery pump 48 may be a mechanical pump or an electric pump, as in the case of the pump 38. When the battery pump 48 is operated, the refrigerant circulates in the battery refrigerant flow passage 46 from the battery liquid-tight space 45 through the battery radiator 49 and the battery pump 48 in this order, returning to the battery liquid-tight space 45 (see the refrigerant flow direction Y2). As a result, the refrigerant is cooled when passing through the battery radiator 49, and reaches the battery liquid-tight space 45 in a relatively low temperature state after flowing through the battery pump 48. Therefore, the battery 31 is cooled by the refrigerant that has reached the battery liquid-tight space 45. In this way, the battery 31 can be cooled by the cooling structure 43 that is different from the cooling structure 32 for the electric components other than the battery 31. The refrigerant that has passed through the battery liquid-tight space 45 becomes relatively hot due to heat exchange with the battery 31, but is cooled again when passing through the battery radiator 49. In other words, the temperature T3 of the coolant flowing out of the liquid-tight space 45 for the battery is higher than the temperature T4 of the coolant flowing into the liquid-tight space 45 for the battery.

[0068] The eleventh embodiment shown in Figs. 13 and 14 is a modified example of the tenth embodiment, in which the above-mentioned liquid-tight space 45 for the battery is provided inside the battery 31, specifically between the battery cell 31A and the package 31B. The inner case 40 includes a first inner case 51 that covers at least a part of the outer surface 31C of the battery 31 in the storage space 30A of the battery case 30, and a second inner case 52 that covers at least a part of the first inner case 51. The second inner case 52 defines the above-mentioned liquid-tight space 30B between the outer case 41 and the second inner case 52. The outer case 41 may be a box-like shape that covers the entire second inner case 52 (not shown), or may be a cover-like shape that covers only a part of the outer surface 52A (specifically, the lower surface 52AA) of the second inner case 52, as shown in Figs. 13 and 14.

[0069] According to the configuration of the eleventh embodiment, when the battery pump 48 is operated, the refrigerant for cooling the battery cells 31A returns from the battery liquid-tight space 45 provided inside the battery 31 to the battery liquid-tight space 45 through the battery radiator 49. Therefore, the refrigerant is cooled when passing through the battery radiator 49, and returns to the battery liquid-tight space 45 at a relatively low temperature to cool the battery cells 31A in the battery 31. In this way, the battery cells 31A can be cooled by the cooling structure 43 separate from the cooling structure 32 for the electric components other than the battery 31.

[0070] The twelfth embodiment shown in Fig. 15 is a modification of the eleventh embodiment, in which the above-mentioned radiator 42 (see Fig. 13) is omitted in the refrigerant flow path 36 of the cooling structure 32. In other words, no radiator is attached to the refrigerant flow path 36. According to this configuration, a radiator is omitted in the cooling structure 32 for electrical components other than the battery 31, so that the number of components in the cooling structure 32 can be reduced.

[0071] The various features described above may be combined as appropriate.

[0072] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical content of the present invention, and the present invention should not be interpreted as being limited to these examples, and the scope of the present invention is limited only by the appended claims. [Explanation of symbols]

[0073] 1: electric vehicle, 2: front wheel, 3: rear wheel, 20: electric motor, 22: inverter, 30: battery case, 30A: storage space, 30B: liquid-tight space, 30C: refrigerant inlet, 30D: refrigerant outlet, 30E: air-cooled section, 31: battery, 31C: outer surface, 33: cooling jacket, 33A: motor cooling jacket, 33B: inverter cooling jacket, 36: refrigerant flow path, 38: pump, 40: inner case, 40A: outer surface, 40AA: upper surface, 40AB: lower surface, 40AC: side surface, 41: outer case, 41AA: lower surface, 42: radiator, 45: liquid-tight space for battery, 46: cooling for battery Medium Flow path, 48: battery pump, 49: battery radiator, 51: first inner case, 52: second inner case, T1: temperature of refrigerant flowing from refrigerant inlet 30C into liquid-tight space 30D, T2: temperature of refrigerant flowing out from refrigerant outlet 30D, X: area between front wheel 2 and rear wheel 3, Y1: flow direction of refrigerant flowing through refrigerant flow path 36

Claims

1. an electric motor that generates a driving force for propelling an electric vehicle; A battery; an inverter that converts DC power generated by the battery into AC power and supplies the AC power to the electric motor; A battery case including an accommodation space for accommodating the battery, a liquid-tight space isolated from the accommodation space, and a refrigerant inlet and a refrigerant outlet communicating with the liquid-tight space, the battery case having an air-cooling section that partitions the liquid-tight space and is exposed to a running wind; a cooling jacket provided on at least one of the electric motor and the inverter; a pump for causing the coolant to flow in a coolant flow path from the liquid-tight space through the coolant outlet, the cooling jacket, and the coolant inlet in this order and back to the liquid-tight space, a temperature of the refrigerant flowing into the liquid-tight space from the refrigerant inlet is higher than a temperature of the refrigerant flowing out from the refrigerant outlet.

2. the battery case includes an inner case covering at least a portion of an outer surface of the battery, and an outer case in which the air-cooling unit is provided and covering at least a portion of the outer surface of the inner case, The electric vehicle according to claim 1 , wherein the liquid-tight space is defined between the inner case and the outer case.

3. The electric vehicle according to claim 2 , wherein an outer surface of the inner case includes a plurality of surfaces exposed to the liquid-tight space.

4. The electric vehicle according to claim 2 , wherein the air-cooling portion is provided on a lower surface of the outer case.

5. A liquid-tight space for a battery is provided inside the battery for cooling the battery cells, the inner case includes a first inner case that covers at least a portion of an outer surface of the battery within the accommodation space, and a second inner case that covers at least a portion of the first inner case to partition the liquid-tight space between the first inner case and the outer case, A battery radiator; 3. The electric vehicle according to claim 2, further comprising: a battery pump for causing refrigerant to flow in a battery refrigerant flow path that runs from the battery liquid-tight space through the battery radiator and returns to the battery liquid-tight space.

6. A liquid-tight space for a battery is defined between the inner case and the battery, A battery radiator; 3. The electric vehicle according to claim 2, further comprising: a battery pump for causing refrigerant to flow in a battery refrigerant flow path that runs from the battery liquid-tight space through the battery radiator and returns to the battery liquid-tight space.

7. The electric vehicle according to claim 5 , wherein a radiator is not installed in the coolant flow path.

8. The electric vehicle according to claim 1 , further comprising a radiator that cools the coolant flowing in the coolant flow passage from the coolant outlet to the cooling jacket.

9. The electric vehicle according to claim 8 , wherein the radiator is disposed forward of the battery case.

10. The electric vehicle according to claim 1 , wherein a radiator is not installed.

11. the cooling jacket includes a motor cooling jacket provided on the electric motor and an inverter cooling jacket provided on the inverter, 11. The electric vehicle according to claim 1, wherein the inverter cooling jacket is located further upstream from the refrigerant inlet than the motor cooling jacket in a flow direction of the refrigerant flowing through the refrigerant flow path, so that the refrigerant flowing out from the refrigerant outlet passes through the inverter cooling jacket and then passes through the motor cooling jacket.

12. The electric vehicle according to any one of claims 1 to 10, wherein the air-cooling portion includes a heat sink.

13. The electric vehicle according to any one of claims 1 to 10, wherein the air-cooling unit is detachable from the battery case.

14. The electric vehicle according to any one of claims 1 to 10, which is a saddle-ride type electric vehicle including a front wheel and a rear wheel.

15. The electric vehicle according to claim 14, wherein the battery case is disposed forward of the electric motor and the inverter in a region between the front wheels and the rear wheels.

16. The electric vehicle according to claim 15, wherein the electric motor is disposed rearward of the inverter.

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