Cooling device and cooling system

Abstract

To provide a small cooling device and cooling system for batteries installed in railway vehicles. [Solution] The cooling device according to this embodiment is provided at the lower part of the railway vehicle facing the running surface of the railway vehicle and comprises a housing for housing a storage battery, a cooling plate that cools the storage battery by exchanging heat between a refrigerant circulating inside and the storage battery, and a refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate.

Description

Technical Field

[0001] The present embodiment relates to a cooling device and a cooling system.

Background Art

[0002] Attempts have been made to mount storage batteries on railway vehicles and run the vehicles using electric power from the storage batteries. The temperature of the storage battery rises during charge and discharge, and continued use in a high-temperature state accelerates deterioration of the storage battery. To prevent this, a device for cooling the storage battery is required. In many cases, water-cooled refrigerant circuits that dissipate heat using cooling water, chiller-type refrigerant circuits having two circulation systems of water and refrigerant, and the like are employed in storage battery cooling devices.

[0003] However, in the case of a water-cooled refrigerant circuit, a large heat exchanger is required to compensate for low cooling efficiency. Further, in the case of a chiller-type refrigerant circuit, since there are two circulation systems of water and refrigerant, the configuration inevitably becomes large. As a result, cooling devices employing these refrigerant circuits are difficult to mount on railway vehicles.

Prior Art Literature

Patent Literature

[0004]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] An object of the present embodiment is to provide a compact cooling device and a compact cooling system for a storage battery mounted on a railway vehicle.

Means for Solving the Problem

[0006] To solve the above problems, the cooling device according to this embodiment is provided at the lower part of the railway vehicle facing the running surface of the railway vehicle and comprises a housing for housing a storage battery, a cooling plate that cools the storage battery by exchanging heat between a refrigerant circulating inside and the storage battery, and a refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate.

[0007] The cooling system according to this embodiment comprises a storage battery mounted on a railway vehicle, a housing provided at the lower part of the railway vehicle facing the running surface of the railway vehicle and housing the storage battery, a cooling plate that cools the storage battery by exchanging heat between a refrigerant circulating inside and the storage battery, and a refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the configuration of the storage battery and housing according to the embodiment. [Figure 2] This is an exploded perspective view showing the detailed configuration of the storage compartment. [Figure 3] This is a perspective view showing the detailed configuration of the storage compartment. [Figure 4] This is a perspective view showing the detailed configuration of the storage compartment. [Figure 5] These are a plan view, a front view, and a side view showing the detailed configuration of a direct-cooling refrigerant circuit according to an embodiment. [Figure 6] This is a schematic diagram showing how the battery, housing, and refrigerant circuit according to the embodiment are installed in the lower part of a railway vehicle. [Figure 7] This is a schematic diagram showing how the battery, housing, and refrigerant circuit according to the embodiment are installed in the lower part of a railway vehicle. [Figure 8] This is a schematic diagram showing the configuration of a cooling device having a water-cooled refrigerant circuit according to Comparative Example 1. [Figure 9] These are a plan view, a front view, and a side view showing the detailed configuration of the water-cooled refrigerant circuit according to Comparative Example 1. [Figure 10] This is a schematic diagram showing how the battery and cooling system according to Comparative Example 1 are installed in the underside of a railway vehicle. [Figure 11] This is a schematic diagram showing the configuration of a cooling device having a chiller-type refrigerant circuit according to Comparative Example 2. [Figure 12] These are a plan view, a front view, and a side view showing the detailed configuration of the chiller-type refrigerant circuit according to Comparative Example 2. [Figure 13] This is a schematic diagram showing how the storage battery and cooling device according to Comparative Example 2 are installed in the underside of a railway vehicle. [Figure 14] This is a simulation result comparing the cooling performance of each refrigerant circuit. [Modes for carrying out the invention]

[0009] This embodiment will be described below with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numeral, and detailed descriptions are omitted as appropriate.

[0010] (Embodiment) Figure 1 is a schematic diagram showing the configuration of the cooling device for the battery 1 according to this embodiment. The cooling device includes a housing section 2 (2A, 2B, 2C) that houses the battery 1. The housing section 2 has side members 2A and 2B that fix the sides of the battery 1, and a base member 2C that supports the bottom surface of the battery 1. The base member 2C functions as a cooling plate and cools the battery 1 by exchanging heat between the battery 1 and the refrigerant. In other words, in this embodiment, the base member that supports the bottom surface of the battery 1 and the cooling plate that cools the battery 1 are common to each other. The cooling plate includes a heat exchange pipe that circulates liquefied refrigerant in its internal space. The heat exchange pipe is connected to the inner surface of the plate body (housing) in a heat exchange manner. As the refrigerant circulates within the heat exchange pipe, the cooling plate is forcibly cooled by the heat of vaporization of the refrigerant. The heat exchange pipe is made of copper or aluminum, etc.

[0011] Further, the cooling device includes a compressor 4 that compresses a refrigerant, a condenser 5 that causes the refrigerant to exchange heat with outside air to condense the refrigerant, and an expansion valve 6 that expands the refrigerant. A direct refrigerant cooling type refrigerant circuit is formed by the compressor 4, the condenser 5, and the expansion valve 6. A refrigerant circuit may be defined as one that further includes a heat exchange pipe in the refrigerant circuit. The refrigerant circuit circulates the refrigerant by repeatedly cooling the refrigerant, supplying the cooled refrigerant to a cooling plate (more specifically, a heat exchange pipe inside the cooling plate), receiving the refrigerant output from the heat exchange pipe (more specifically, the heat exchange pipe inside the cooling plate), and cooling the received refrigerant. As will be described later, the direct refrigerant cooling type refrigerant circuit is more compact and has higher cooling performance than water-cooled type or chiller type refrigerant circuits.

[0012] Figure 2 is an exploded perspective view showing the detailed configuration of the housing portion 2. Figures 3 and 4 are perspective views showing the detailed configuration of the housing portion 2. In these figures, the X-axis, Y-axis, and Z-axis indicate directions in a three-dimensional space, and gravity acts in the -Y direction. Note that Figures 3 and 4 show a state where the storage battery 1 is exposed by cutting a part of the protective case 3.

[0013] As shown in Figure 2, a total of 25 rectangular parallelepiped storage batteries 1, five in the X direction and five in the Y direction, are housed in the housing portion 2. These storage batteries 1 are connected in any pattern, and the connection form is not limited to a specific one. As an example, they are connected in series in the Z-axis direction to form a plurality of strings, and these strings are connected in parallel to an external control circuit (not shown). The housing portion 2 includes side members 2A and 2B that support (fix) the side surfaces of the storage batteries 1, and a base member 2C that supports the bottom surfaces of the storage batteries 1. As a material of the base member 2C, a hard metal having high thermal conductivity and capable of withstanding the weight of the storage batteries 1, for example, iron or stainless steel, can be used. The same applies to the side members 2A and 2B.

[0014] As shown in Figures 2 to 4, the battery 1 is covered with a resin protective case 3 that protects the battery 1 from impact and dirt. Optionally, a thermal conductive material (not shown) may be provided between the battery 1 and the base member 2C. The thermal conductive material can increase the heat exchange rate between the battery 1 and the base member 2C. Multiple ribs 2D are formed on the lower surface of the base member 2C. The ribs 2D improve the strength of the base member 2C. Furthermore, as will be described later, when the housing 2 is installed under a railway vehicle facing the running surface of the railway vehicle, the ribs 2D can improve the cooling efficiency of the battery 1 and provide protection from flying debris.

[0015] Figure 5 is a plan view, front view, and side view showing the detailed configuration of the direct-cooling refrigerant circuit according to this embodiment. Figure 6 is a schematic diagram showing the battery 1, housing 2, and refrigerant circuit according to this embodiment installed in the lower part of a railway vehicle 10. In these figures, the X, Y, and Z axes indicate directions in three-dimensional space, and gravity acts in the -Y direction. As shown in Figure 5, the compressor 4 of the direct-cooling refrigerant circuit is relatively small and can be installed horizontally with its longitudinal direction horizontal. The total dimensions of the direct-cooling refrigerant circuit according to this embodiment are sufficiently smaller than those of Comparative Examples 1 and 2, which will be described later. Note that the expansion valve 6 is sufficiently smaller than the compressor 4 and condenser 5 and is therefore not shown.

[0016] As shown in FIG. 6, in the case of a direct refrigerant cooling device, all components can be installed in the space between the bogies 11 at the lower part of the railway vehicle 10 without occupying space in the passenger compartment of the railway vehicle 10. Alternatively, the storage battery 1, the housing portion 2 and the refrigerant circuit may all be installed as an integrated unit 13. This allows the integrated unit to be removed for maintenance and inspection during maintenance work, facilitating maintenance, management and replacement. A refrigerant circuit for vehicle interior air conditioning may be provided on the upper portion 12 of the railway vehicle 10. In this case, only the storage battery 1, the housing portion 2 and the cooling plate 3 are installed at the lower part of the railway vehicle 10, and the compressor 4, the condenser 5 and the expansion valve 6 may be shared with the refrigerant circuit for vehicle interior air conditioning installed on the upper portion 12 of the vehicle. That is, although piping routing is required, the compressor 4, the condenser 5 and the expansion valve 6 are not installed at the lower part of the railway vehicle 10, and the refrigerant circuit for vehicle interior air conditioning installed on the upper portion 12 of the railway vehicle 10 is connected to the heat exchange pipe in the cooling plate at the lower part of the vehicle.

[0017] Furthermore, as described above, a plurality of ribs 2D are formed on the lower surface of the base member 2C. Therefore, most flying stones generated as the railway vehicle 10 travels rebound off the ribs 2D without directly striking the base member 2C. This enables the housing portion 2 and the storage battery 1 housed therein to be protected from flying stones. Optionally, as shown in FIG. 7, the refrigerant circuit may be protected from flying stones by providing a protection member 14 made of iron, stainless steel or the like at the lower part of the refrigerant circuit.

[0018] Furthermore, since the housing portion 2 is installed at the lower part of the railway vehicle 10, the base member 2C is exposed to outside air when the vehicle travels, and the plurality of ribs 2D on the lower part of the base member 2C increase the contact area between the base member 2C and the outside air. This promotes heat transfer via ventilation, thereby improving the cooling efficiency of the storage battery 1.

[0019] (Comparative Example 1) Figure 8 is a schematic diagram showing the configuration of a cooling device (water-cooled cooling device) having a water-cooled refrigerant circuit according to Comparative Example 1. Figure 9 is a plan view, front view, and side view showing the detailed configuration of the water-cooled cooling device according to Comparative Example 1. Figure 10 is a schematic diagram showing the storage battery 1, housing, and refrigerant circuit according to Comparative Example 1 installed in the lower part of a railway vehicle 10. In these figures, the X, Y, and Z axes indicate directions in three-dimensional space, and gravity acts in the -Y direction.

[0020] Referring to Figure 8, the water-cooled refrigerant circuit includes a pump 212 that pressurizes water as a refrigerant, a heat exchange pipe in a cooling plate 213 that cools the battery 1 by exchanging heat between the battery 1 and water, a water storage tank 214 that stores water, and a heat exchanger 215 that exchanges heat between water and outside air. Referring to Figure 9, the water-cooled refrigerant circuit has a water storage tank 214 and a large heat exchanger 215 that are not present in the direct refrigerant cooling type of this embodiment. The total dimensions of the water-cooled refrigerant circuit according to Comparative Example 1 are approximately 50 percent larger than those of the direct refrigerant cooling type refrigerant circuit according to this embodiment.

[0021] As shown in Figure 10, in the case of a water-cooled refrigerant circuit, the water storage tank 214 and the large heat exchanger 215 encroach on the space inside the passenger car of the railway vehicle 10. Furthermore, it is difficult to install all the components that make up the cooling system in the space between the bogies 11 at the bottom of the railway vehicle 10. Part of the bogie 11 on the right is missing, which indicates that not all the components can fit in the space between the bogies 11. Therefore, it is not possible to install the battery 1, housing 2, and refrigerant circuit as an integrated unit, and some components of the refrigerant circuit must be installed inside the passenger compartment or on top of the vehicle. As a result, piping needs to be routed, and maintenance is difficult as it requires disconnecting the water lines and refrigerant lines.

[0022] (Comparative Example 2) Figure 11 is a schematic diagram showing the configuration of a cooling device (chiller-type cooling device) having a chiller-type refrigerant circuit according to Comparative Example 2. Figure 12 is a plan view, front view, and side view showing the detailed configuration of the chiller-type cooling device according to Comparative Example 2. Figure 13 is a schematic diagram showing the storage battery 1, housing, and refrigerant circuit according to Comparative Example 2 installed in the lower part of a railway vehicle 10. In these figures, the X, Y, and Z axes indicate directions in three-dimensional space, and gravity acts in the -Y direction.

[0023] As shown in Figure 11, the chiller-type refrigerant circuit has two circulation systems: one for water and one for refrigerant. The water circulation system includes a pump 312 for pressurizing water, a heat exchange pipe in a cooling plate 313 that cools the battery 1 by exchanging heat between the battery 1 and water, a water storage tank 314 for storing water, and a heat exchanger 315 for exchanging heat between water and refrigerant. The refrigerant circulation system includes a compressor 304 for compressing the refrigerant, a condenser 305 for condensing the refrigerant by exchanging heat with outside air, an expansion valve 306 for expanding the refrigerant, and a heat exchanger 315 for exchanging heat between the refrigerant and water.

[0024] As shown in Figure 12, the chiller-type refrigerant circuit has a pump 312, a water storage tank 314, and a heat exchanger 315, which are not present in the direct-cooling refrigerant circuit of this embodiment. The total dimensions of the chiller-type refrigerant circuit according to Comparative Example 2 are approximately 30 percent larger than those of the direct-cooling refrigerant circuit according to this embodiment.

[0025] As shown in Figure 13, in the case of a water-cooled refrigerant circuit, the water storage tank 314 encroaches on the interior space of the passenger car 10. Furthermore, it is difficult to install all the components that make up the cooling system in the space between the bogies 11 at the bottom of the railway vehicle 10. Part of the bogie 11 on the right is missing, which indicates that not all the components can fit in the space between the bogies 11. Therefore, it is not possible to install the battery 1, housing 2, and refrigerant circuit as an integrated unit, and some components of the refrigerant circuit must be installed inside the passenger compartment or on top of the vehicle. As a result, piping needs to be routed, and maintenance requires disconnecting the water lines and refrigerant lines, resulting in poor maintainability.

[0026] (Comparative Example 3) Patent Document 1 (Japanese Patent Publication No. 2009-238389) describes a configuration in which a storage battery is cooled by circulating a refrigerant inside a cooling plate made of aluminum. However, because a soft metal like aluminum cannot withstand the weight of the storage battery, the cooling plate flexes, creating a gap between the storage battery and the cooling plate. As a result, the cooling efficiency of the storage battery decreases. To avoid this, Patent Document 1 provides a separate high-strength member that supports both the storage battery and the cooling plate. This has the problem of increasing the size of the device.

[0027] In contrast, in this embodiment, the base member 2C, which is made of a hard metal such as iron or stainless steel, also functions as a cooling plate. Furthermore, since the refrigerant direct cooling type refrigerant circuit according to this embodiment has higher cooling performance than water-cooled or chiller-type refrigerant circuits, the battery 1 can be sufficiently cooled even if the base member 2C (cooling plate) is made of iron or stainless steel, which has a lower thermal conductivity than aluminum. This makes it possible to miniaturize the device while preventing a gap from forming between the battery 1 and the cooling plate, which would reduce cooling efficiency.

[0028] (Simulation results) Figure 14 shows the simulation results comparing the cooling performance of the direct refrigerant cooling circuit according to this embodiment with the water-cooled refrigerant circuit according to Comparative Example 1 and the chiller-type refrigerant circuit according to Comparative Example 2. In the direct refrigerant cooling (DRC) type, two cases are shown where the material of the base member 2C (cooling plate) is aluminum (Al) and iron (Fe). In the water-cooled (Water) type, the material of the cooling plate is aluminum (Al). In the chiller type (Chiller) type, the material of the cooling plate is aluminum (Al).

[0029] As shown in this figure, the cooling performance of the direct refrigerant cooling system is significantly lower than that of the water-cooled system, with the temperature rise being sufficiently suppressed. Compared to the chiller system, it is still lower, though not as low as the water-cooled system. Furthermore, there is no significant difference in cooling performance between the iron and aluminum materials used for the base component 2C (cooling plate) of the direct refrigerant cooling system.

[0030] As described above, the cooling system for a battery mounted on a railway vehicle according to this embodiment includes a direct refrigerant cooling circuit formed by a compressor 4, a condenser 5, an expansion valve 6, and a heat exchange pipe within a base member 2C that functions as a cooling plate. Compared to water-cooled or chiller-type refrigerant circuits, the direct refrigerant cooling circuit is smaller and all components of the cooling system can be installed in the space between the bogies 11 at the bottom of the railway vehicle 10 without encroaching on the space inside the passenger compartment of the railway vehicle 10. Therefore, the cooling system according to this embodiment is extremely excellent as a cooling system for a battery mounted on a railway vehicle.

[0031] Furthermore, in the cooling device according to this embodiment, the base member 2C that supports the bottom of the battery 1 also functions as a cooling plate for cooling the battery 1. In other words, the base member and the cooling plate are integrated into a single unit. The base member 2C is made of a hard metal such as iron or stainless steel. This makes it possible to miniaturize the device while preventing gaps from forming between the battery 1 and the cooling plate, which would reduce cooling efficiency, compared to a configuration in which the base member and the cooling plate are provided separately.

[0032] Furthermore, in the cooling device according to this embodiment, a plurality of ribs 2D are formed on the lower surface of the base member 2C. This provides effects such as improved strength of the base member 2C, improved cooling efficiency of the storage battery 1, and protection of the device from flying debris.

[0033] Furthermore, by installing only the battery 1, housing 2, and cooling plate 3 in the lower part of the railway vehicle 10, and sharing the compressor 4, condenser 5, and expansion valve 6 with the refrigerant circuit for the in-vehicle air conditioning installed in the upper part of the vehicle, the space in the lower part of the vehicle can be increased, allowing for a larger cooling plate.

[0034] While several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the embodiments. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the embodiments. These embodiments and their variations are included in the scope and spirit of the embodiments, as well as in the claims and their equivalents.

[0035] Furthermore, this embodiment can also be configured as follows. [Item 1] (Cooling device) A housing for a storage battery is provided at the lower part of the railway vehicle, facing the running surface of the railway vehicle, A cooling plate that cools the battery by exchanging heat between the refrigerant circulating inside and the battery, A refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate, A cooling device equipped with a cooling system. [Item 2] The housing portion includes a side member that secures the side of the battery and a base member that supports the bottom surface of the battery. The base member and the cooling plate of the housing are made common. The cooling device described in item 1. [Item 3] The cooling plate is made of iron or stainless steel. A cooling device as described in item 1 or 2. [Item 4] The housing and the cooling plate are installed in the space between the bogies at the bottom of the railway vehicle. A cooling device as described in any one of items 1 to 3. [Item 5] The refrigerant circuit is installed in the space between the bogies at the bottom of the railway vehicle. The cooling device described in item 4. [Item 6] The housing, the cooling plate, and the refrigerant circuit are installed as an integrated unit. The cooling device described in item 5. [Item 7] The aforementioned refrigerant circuit is shared with the refrigerant circuit for the in-car air conditioning system installed on the upper part of the railway vehicle. A cooling device as described in any one of items 1 to 3. [Item 8] A rib is formed on the lower surface of the base member opposite to the battery. The cooling device described in item 2. [Item 9] A protective member is provided at the lower part of the refrigerant circuit facing the running surface of the railway vehicle. The cooling device described in item 5. [Item 10] The aforementioned refrigerant circuit is A compressor for compressing the aforementioned refrigerant, A condenser that condenses the aforementioned refrigerant by exchanging heat with the outside air, Includes an expansion valve for expanding the refrigerant, The compressor is installed with its longitudinal direction horizontal. The cooling device described in item 5. [Item 11] (Cooling System) Batteries installed in railway vehicles, A housing for housing the storage battery is provided at the lower part of the railway vehicle facing the running surface of the railway vehicle, A cooling plate that cools the battery by exchanging heat between the refrigerant circulating inside and the battery, A refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate, Cooling system. [Explanation of symbols]

[0036] 1. Storage battery 2. Storage area 2A Side member 2B Side Member 2C Base component (cooling plate) 3. Protective Case 4. Compressor 5. Condenser 6. Expansion valve 10 Railway vehicles 11 bogies 13 units 14 Protective components 212 pumps 213 Cooling Plate 214 Water storage tank 215 Heat exchanger 304 Compressor 305 Condenser 306 Expansion valve 312 Pump 313 Cooling Plate 314 Water storage tank 315 Heat exchanger

Claims

1. A housing for a storage battery is provided on the lower part of the railway vehicle facing the running surface of the railway vehicle, A cooling plate that cools the battery by exchanging heat between the refrigerant circulating inside and the battery, A refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate, A cooling device equipped with a cooling system.

2. The housing portion includes a side member that secures the side of the battery and a base member that supports the bottom surface of the battery. The base member and the cooling plate of the housing are made common. The cooling device according to claim 1.

3. The cooling plate is made of iron or stainless steel. The cooling device according to claim 1.

4. The housing and the cooling plate are installed in the space between the bogies at the bottom of the railway vehicle. The cooling device according to claim 1.

5. The refrigerant circuit is installed in the space between the bogies at the bottom of the railway vehicle. The cooling device according to claim 4.

6. The housing, the cooling plate, and the refrigerant circuit are installed as an integrated unit. The cooling device according to claim 5.

7. The aforementioned refrigerant circuit is shared with the refrigerant circuit for the in-car air conditioning system installed on the upper part of the railway vehicle. The cooling device according to claim 1.

8. A rib is formed on the lower surface of the base member opposite to the battery. The cooling device according to claim 2.

9. A protective member is provided at the lower part of the refrigerant circuit facing the running surface of the railway vehicle. The cooling device according to claim 5.

10. The aforementioned refrigerant circuit is A compressor for compressing the aforementioned refrigerant, A condenser that condenses the aforementioned refrigerant by exchanging heat with the outside air, Includes an expansion valve for expanding the refrigerant, The compressor is installed with its longitudinal direction horizontal. The cooling device according to claim 5.

11. Batteries installed in railway vehicles, A housing for housing the storage battery is provided at the lower part of the railway vehicle facing the running surface of the railway vehicle, A cooling plate that cools the battery by exchanging heat between the refrigerant circulating inside and the battery, A refrigerant circuit that supplies refrigerant to the cooling plate and cools the refrigerant output from the cooling plate, Cooling system.

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