Cooling system

Abstract

To provide a cooling system capable of highly maintaining insulation properties of insulation coolant while suppressing circulation energy loss.SOLUTION: A cooling system has a circulation path which allows non-aqueous insulation coolant to circulate, and a coolant storage part which is provided for the circulation path, and stores the insulation coolant, where the specific gravity of the insulation coolant is smaller than water, the coolant storage part has a moisture removing part inside thereof, and the moisture removing part is fixed to the coolant storage part such that at least a part of its top face directly contact the insulation coolant.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to cooling systems. [Background technology]

[0002] In a cooling system that circulates a coolant to cool electrical components such as a battery, the coolant used is required to have high insulating properties. If moisture gets into the coolant, the moisture may cause problems such as short-circuiting between terminals of the electrical components or corroding the components. In order to prevent an increase in the conductivity of the coolant, for example, Patent Document 1 discloses a technique for installing a filter for removing moisture in the circulation path of a cooling system that uses a non-aqueous insulating coolant.

[0003] Patent Document 2 discloses a cooling device in which a moisture removal filter is arranged to block the coolant discharge part of a coolant storage tank provided in the coolant circulation path. Patent Document 3 discloses a liquid cooling device for electric and electronic components provided with a moisture capture material capable of capturing moisture in the refrigerant by reacting with water. Patent Document 4 discloses a water remover in which granular water-absorbing polymer is enclosed in a wire net with a mesh structure, and Patent Document 5 discloses a method of removing water dispersed in an oil phase using powder of water-absorbing resin enclosed in a resin net bag. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-158432 A [Patent Document 2] JP 2001-050624 A [Patent Document 3] Japanese Patent Application Publication No. 02-216855 [Patent Document 4] Patent Publication No. 2022-097321 [Patent Document 5] JP 2017-104817 A Summary of the Invention [Problem to be solved by the invention]

[0005] If the moisture removal unit is installed in such a way that it blocks the circulation path of the coolant, the flow resistance increases, the flow rate of the coolant decreases, and the cooling performance decreases significantly, so it is necessary to increase the output of the pressure pump to ensure the flow rate. Also, in non-aqueous coolants such as oil, moisture often aggregates and exists as large water droplets, so if a water-absorbing resin is enclosed in the mesh, the water droplets may not be able to pass through the mesh and reach the water-absorbing resin.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide a cooling system that can maintain high insulating properties of an insulating coolant while suppressing circulating energy loss. [Means for solving the problem]

[0007] [1] A cooling system having a circulation path for circulating a non-aqueous insulating cooling liquid, and a cooling liquid storage section provided in the circulation path for storing the insulating cooling liquid, wherein the specific gravity of the insulating cooling liquid is lower than that of water, and the cooling liquid storage section has a moisture removal section therein, and the moisture removal section is fixed to the cooling liquid storage section so that at least a portion of its upper surface is in direct contact with the insulating cooling liquid.

[0008] [2] The cooling system according to [1], wherein at least a portion of the moisture removal section is fixed to a bottom surface of the cooling liquid storage section.

[0009] [3] The cooling system according to [1] or [2], wherein the moisture removal section contains porous zeolite or a water-absorbent resin as a moisture absorbent.

[0010] [4] The cooling system according to [3], wherein the water-absorbing resin is at least one selected from the group consisting of a partially neutralized crosslinked product of polyacrylic acid, a neutralized product of a starch-acrylic acid graft polymer, a hydrolyzate of a starch-acrylonitrile graft polymer, a saponified product of a vinyl acetate-acrylic acid ester copolymer, a crosslinked product of an isobutylene-maleic anhydride copolymer, a hydrolyzate of an acrylonitrile copolymer or an acrylamide copolymer or a crosslinked product thereof, a crosslinked product of an acrylate-acrylamide copolymer, a crosslinked product of a polyvinyl alcohol, a crosslinked product of a modified polyethylene oxide, a crosslinked product of an acrylamide-2-methylpropanesulfonate copolymer, a crosslinked product of a (meth)acryloylalkanesulfonate copolymer, a crosslinked carboxymethylcellulose salt, and a crosslinked polymer of a cationic monomer.

[0011] [5] The cooling system according to [3] or [4], wherein the water-absorbing resin is a partially neutralized crosslinked product of polyacrylic acid or a neutralized product of a starch-acrylic acid graft polymer. Effect of the Invention

[0012] The cooling system according to the present disclosure has an advantage of being able to maintain high insulating properties of the insulating coolant while suppressing circulation energy loss. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic configuration diagram illustrating an example of a cooling system according to the present disclosure. [Diagram 2] 2 is a schematic cross-sectional view showing an example of a coolant reservoir in the present disclosure. FIG. [Diagram 3] 2 is a schematic cross-sectional view illustrating an example of a coolant reservoir in the present disclosure. FIG. [Figure 4] 11 is a schematic cross-sectional view showing another example of a coolant reservoir in the present disclosure. FIG. [Diagram 5] 1 is a schematic cross-sectional view showing an example of a coolant reservoir in which a conventional moisture remover is disposed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The cooling system according to the present disclosure will now be described in detail.

[0015] FIG. 1 is a schematic diagram showing an example of a cooling system according to the present disclosure. The cooling system 100 shown in FIG. 1 includes a circulation path 1 for circulating a non-aqueous insulating coolant, and a coolant reservoir 2 provided in the circulation path 1 for storing the insulating coolant. The flow of the insulating coolant in the circulation path 1 can be formed by using a pump 10 or the like. The cooling system 100 according to the present disclosure can be mounted on a vehicle, for example, and can be used to cool heat-generating devices such as an inverter 11, an oil cooler 12, and a battery 13 provided in series in the circulation path 1. A radiator 14 is provided in the circulation path 1 to perform heat exchange with outside air, thereby cooling the insulating coolant that has been heated by cooling the heat-generating devices.

[0016] 2 is a schematic cross-sectional view showing an example of a coolant storage unit in the present disclosure. The moisture removal unit 4 is fixed to the coolant storage unit 2 so that at least a part of its upper surface is in direct contact with the insulating cooling liquid 3. Since the specific gravity of the insulating cooling liquid 3 used in the present disclosure is smaller than that of water, moisture mixed into the insulating cooling liquid 3 sinks in the coolant storage unit 2, coagulates, and becomes droplets 21, which are absorbed by the moisture removal unit 4 (moisture absorber 5) and removed from the insulating cooling liquid 3.

[0017] In the cooling system of the present disclosure, the moisture removal part is fixed to the cooling liquid reservoir so that at least a part of the upper surface of the moisture removal part is in direct contact with the insulating cooling liquid, so that the moisture in the insulating cooling liquid can be efficiently removed without stagnation of the flow of the insulating cooling liquid in the circulation path, thereby suppressing the circulation energy loss and maintaining high insulating properties of the insulating cooling liquid.

[0018] If the moisture removal unit is installed in such a way that it blocks the circulation path of the cooling liquid or the inlet and outlet of the cooling liquid storage unit so that all the cooling liquid passes through the moisture removal unit, the flow resistance increases, the flow rate of the cooling liquid decreases, and the cooling performance decreases significantly. Therefore, it is necessary to increase the output of the pressure pump to ensure the flow rate. On the other hand, as described above, in the present disclosure, since an insulating cooling liquid with a specific gravity smaller than that of water is used, the moisture mixed in the insulating cooling liquid sinks in the cooling liquid storage unit and gathers at the bottom of the cooling liquid storage unit. Therefore, by absorbing the moisture by arranging the moisture removal unit at the place where the water droplets gather in the cooling liquid storage unit, it is possible to remove the moisture from the insulating cooling liquid without increasing the output of the pressure pump.

[0019] In addition, in a non-aqueous cooling liquid such as oil, if a moisture absorber is enclosed in a mesh-structured bag or the like, large aggregated water droplets may not be able to pass through the mesh and may not be able to reach the water-absorbing resin. On the other hand, in the present disclosure, the moisture removal part is fixed to the cooling liquid storage part so that at least a part of its upper surface is in direct contact with the insulating cooling liquid, so that the moisture removal part can smoothly and quickly absorb water droplets without being hindered by a structure such as a mesh bag interposed between the moisture absorber of the moisture removal part and the insulating cooling liquid.

[0020] The cooling system according to the present disclosure includes a circulation path for circulating an insulating cooling liquid, and a cooling liquid reservoir for storing the insulating cooling liquid. Each component of the cooling system according to the present disclosure will be described below.

[0021] 1. Insulating coolant The insulating coolant used in the present disclosure is not particularly limited as long as it is a non-aqueous insulating liquid with a specific gravity smaller than that of water. For example, mineral oils containing hydrocarbon compounds such as aromatic hydrocarbons, paraffinic hydrocarbons, and naphthenic (cycloalkane) hydrocarbons can be used.

[0022] 2. Circulation route The circulation path in the cooling system of the present disclosure is a path for circulating the insulating cooling liquid. The circulation path is not particularly limited as long as it has piping for circulating the insulating cooling liquid between the cooled body and the cooling liquid reservoir, and general piping similar to piping for circulating lubricating oil or the like can be used.

[0023] 3. Coolant reservoir The cooling liquid reservoir is provided in the circulation path and stores the insulating cooling liquid. The material, shape, size, etc. of the cooling liquid reservoir are not particularly limited as long as the insulating cooling liquid can be stored therein. For example, the shape of the cooling liquid reservoir may be a rectangular or cylindrical container made of resin or metal, and may be appropriately set depending on the shape of the place where the cooling liquid reservoir is placed and the amount of insulating cooling liquid stored therein.

[0024] The type of the coolant storage section is not particularly limited, and for example, a single-mouth container such as a pressurized reserve tank for a radiator (see FIG. 3(a)) can be used. A two-mouth container as exemplified in FIG. 3(b) may also be used. In the case of a two-mouth container, one mouth may be open to the atmosphere, like an open-to-atmospheric reserve tank, and insulating coolant may flow in / out from the other mouth, or it may be a circulation type in which insulating coolant flows in from one mouth and is discharged from the other mouth.

[0025] A moisture removal unit is fixed inside the cooling liquid storage unit. The position of the moisture removal unit in the cooling liquid storage unit is not particularly limited as long as it is a position that does not hinder the flow of the insulating cooling liquid, and it can be arranged on the bottom surface or side surface of the cooling liquid storage unit so as not to block the inlet and outlet of the insulating cooling liquid. In particular, it is preferable that at least a part of the moisture removal unit is arranged on the bottom surface of the cooling liquid storage unit. This is because it can efficiently absorb water droplets that have sunk to the bottom surface of the cooling liquid storage unit due to the specific gravity difference. In this case, the moisture removal unit may be arranged only on a part of the bottom surface of the cooling liquid storage unit, or may be arranged on the entire bottom surface.

[0026] The moisture removal section can be fixed to the coolant storage section by directly or indirectly fixing the moisture absorber of the moisture removal section to the coolant storage section. For example, when the moisture absorber of the moisture removal section is a pellet-shaped or block-shaped material having a size of 5 mm or more, the moisture removal section 4 consisting only of the moisture absorber 5 can be directly bonded and fixed to the bottom surface of the coolant storage section 2, as shown in FIG. 2. When the size of the moisture absorber pellets or blocks is small, the surface area is large, so high water absorption performance can be exhibited. On the other hand, when the size of the moisture absorber pellets or blocks is large, high adhesion can be exhibited. Therefore, the size of the moisture absorber is preferably small enough to exhibit stable adhesion, and can be appropriately selected and used depending on the characteristics required for the moisture removal section.

[0027] In addition, when the moisture absorber is a powder or particulate substance with a size of less than 5 mm, as exemplified in FIG. 4, the moisture absorber 5 can be dispersed and arranged in a resin piece (resin-embedded portion 6), and the resin-embedded portion 6 containing the moisture absorber 5 can be adhesively fixed to the bottom surface of the coolant storage portion 2, thereby indirectly fixing the moisture absorber 5 to the coolant storage portion 2. When the moisture removal portion has a moisture absorber and a resin-embedded portion, the moisture absorber is arranged so that at least a part of the surface of the moisture absorber is exposed to the surface (upper surface) of the resin-embedded portion. By arranging such a moisture removal portion so as to be immersed in the insulating cooling liquid, the moisture absorber can be brought into direct contact with the insulating cooling liquid.

[0028] The moisture absorbent may be, for example, a porous zeolite such as molecular sieve, or a water-absorbing resin.The water-absorbing resin may be, for example, a crosslinked polyacrylic acid partial neutralization product, a neutralized starch-acrylic acid graft polymer, a hydrolyzate of a starch-acrylonitrile graft polymer, a saponification product of a vinyl acetate-acrylic acid ester copolymer, a crosslinked isobutylene-maleic anhydride copolymer, a hydrolyzate of an acrylonitrile copolymer or an acrylamide copolymer, or a crosslinked product thereof, a crosslinked acrylate-acrylamide copolymer, a crosslinked polyvinyl alcohol, a crosslinked modified polyethylene oxide, a crosslinked acrylamido-2-methylpropanesulfonate copolymer, a crosslinked (meth)acryloylalkanesulfonate copolymer, a crosslinked carboxymethylcellulose salt, or a crosslinked polymer of a cationic monomer, and the like.Among them, a crosslinked polyacrylic acid partial neutralization product and a neutralized starch-acrylic acid graft polymer may be preferably used.

[0029] The resin used in the resin-filled portion is not particularly limited as long as it is resistant to the insulating cooling liquid, and examples of the resin that can be used include thermosetting resins such as epoxy resin, polyfunctional cyanate ester resin, polyfunctional maleimide-cyanate ester resin, polyfunctional maleimide resin, unsaturated polyester resin, and unsaturated group-containing polyphenylene ether resin.

[0030] 4. Cooling system The use of the cooling system of the present disclosure is not particularly limited, and may be used, for example, to cool batteries, inverters, oil coolers, etc. of vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, diesel-powered vehicles, etc. The cooling system of the present disclosure may also be used to cool electrical components of moving objects other than vehicles (for example, trains, ships, and aircraft), machine tools, information processing devices, etc.

[0031] The cooling system may include a pressure pump for generating a circulating flow of the insulating coolant, and a heat exchanger such as a radiator for lowering the temperature of the insulating coolant after cooling the object to be cooled. In addition, the circulation path may include sensors for measuring the temperature, electrical conductivity, water content, etc. of the insulating coolant, an alarm unit for notifying the surroundings when the measured value exceeds a threshold value, and a control unit for controlling these components.

[0032] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. EXAMPLES

[0033] [Example 1] As shown in FIG. 2, a cooling liquid storage section 2 having a moisture removal section 4 in which a moisture absorber 5 made of a water-absorbent resin is adhesively fixed to the bottom surface of the cooling liquid storage section 2 was filled with a non-aqueous insulating cooling liquid 3, water droplets 21 were added, and the storage section 2 was left to stand for a certain period of time.

[0034] [Example 2] As shown in FIG. 4, a moisture removal section 4 having a moisture absorber 5 (water-absorbent resin) exposed on the top surface of a resin-embedded section 6 is fixed to the bottom surface of a cooling liquid storage section 2. The cooling liquid storage section 2 is filled with a non-aqueous insulating cooling liquid 3, water droplets 21 are added, and the cooling liquid storage section 2 is left to stand for a certain period of time.

[0035] [Comparative Example] As shown in FIG. 5, the cooling liquid storage section 2 has a moisture removal section 25 in which a moisture absorber 23, a water-absorbent resin, is sealed in a mesh bag 24 with a mesh size of about 1 mm at the bottom of the cooling liquid storage section 2. The cooling liquid storage section 2 is filled with a non-aqueous insulating cooling liquid 3, water droplets 21 are added, and the cooling liquid storage section 2 is left to stand for a certain period of time.

[0036] [evaluation] In Examples 1 and 2, the water droplets sank due to the difference in specific gravity, reached the upper surface of the moisture removal section, and were absorbed by the moisture absorber, and the moisture in the insulation cooling liquid was removed. On the other hand, in the comparative example, the water droplets reached the upper surface of the moisture removal section as in Examples 1 and 2, but remained on the moisture removal section and were not absorbed by the moisture removal section, and the moisture in the insulation cooling liquid could not be removed. This is presumably because the surface tension was stronger than the force with which the water droplets would sink into the mesh bag under their own weight, and the water droplets could not pass through the mesh structure and reach the surface of the moisture absorber in the mesh bag. [Explanation of symbols]

[0037] 1...Circulation route 2...Coolant reservoir 3…Insulating coolant 4...Moisture removal section 5... Moisture absorbent 100 … Cooling system

Claims

1. a circulation path for circulating a non-aqueous insulating cooling liquid; a cooling liquid reservoir provided in the circulation path and configured to store the insulating cooling liquid, The specific gravity of the insulating cooling liquid is less than that of water, the cooling liquid reservoir has a moisture removal section therein, The water removal portion is secured to the cooling liquid reservoir such that at least a portion of an upper surface of the water removal portion is in direct contact with the insulating cooling liquid.

2. The cooling system according to claim 1 , wherein at least a portion of the water remover is fixed to a bottom surface of the coolant reservoir.

3. 3. The cooling system according to claim 1, wherein the moisture removing section contains porous zeolite or a water-absorbent resin as a moisture absorbent.

4. The cooling system according to claim 3, wherein the water-absorbing resin is at least one selected from the group consisting of a partially neutralized polyacrylic acid crosslinked product, a neutralized product of a starch-acrylic acid graft polymer, a hydrolyzate of a starch-acrylonitrile graft polymer, a saponified product of a vinyl acetate-acrylic acid ester copolymer, an isobutylene-maleic anhydride copolymer crosslinked product, a hydrolyzate of an acrylonitrile copolymer or an acrylamide copolymer or a crosslinked product thereof, an acrylate-acrylamide copolymer crosslinked product, a polyvinyl alcohol crosslinked product, a modified polyethylene oxide crosslinked product, an acrylamide-2-methylpropanesulfonate copolymer crosslinked product, a (meth)acryloylalkanesulfonate copolymer crosslinked product, a crosslinked carboxymethylcellulose salt, and a crosslinked polymer of a cationic monomer.

5. 5. The cooling system according to claim 4, wherein the water-absorbing resin is a partially neutralized crosslinked product of polyacrylic acid or a neutralized product of a starch-acrylic acid graft polymer.

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