JP4134359B2 - Battery cooling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery (storage battery) cooling device, and is suitable for cooling a battery mounted on a vehicle such as an electric vehicle or a hybrid vehicle.
[0002]
[Prior art]
A battery mounted on a vehicle such as an electric vehicle or a hybrid vehicle serves as a power source for an electric motor for driving the vehicle, and therefore needs to be increased in voltage and capacity. By the way, in such an in-vehicle battery, heat is generated due to a chemical reaction or Joule loss in each battery during charging and discharging, and the temperature of the battery is increased, which adversely affects the performance and life of the battery.
[0003]
Thus, various types of cooling devices for cooling the battery have been proposed. For example, in Japanese Patent Laid-Open No. 5-344606, a battery is housed in a sealed case into which a low-pressure refrigerant flows in a refrigeration cycle for vehicle air conditioning, and the battery is cooled by absorbing the latent heat of evaporation of the low-pressure refrigerant from the battery. Things have been proposed.
[0004]
[Problems to be solved by the invention]
By the way, in-vehicle batteries, specifically, nickel-metal hydride batteries, generate hydrogen gas due to the high temperature of the batteries, and the internal pressure of the battery gradually increases. Therefore, the battery is provided with a relief valve as a safety valve. Therefore, when the battery internal pressure reaches a predetermined value and the relief valve is opened, hydrogen gas inside the battery is released into the sealed case.
[0005]
Here, hydrogen gas has a very low boiling point compared to the refrigerant in the refrigeration cycle, and hydrogen gas acts as a non-condensable gas in the refrigeration cycle, so that hydrogen gas is released into the sealed case, and the hydrogen gas in the cycle When the amount of hydrogen gas is accumulated and the amount of hydrogen gas increases, the cooling effect of the battery and the original cooling effect of the cycle are deteriorated.
[0006]
Also, since hydrogen gas is a flammable gas, if the refrigeration cycle is opened during maintenance and inspection of the battery or refrigeration cycle, the hydrogen gas accumulated up to now will be released to the outside of the cycle at a dangerous time. is there.
The present invention has been made in view of the above points, and it is an object of the present invention to eliminate problems caused by the release of hydrogen gas generated in a battery into a refrigerant system path sealed from the outside.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following technical means. That is, the invention according to claim 1 includes a sealed case (10) that houses a nickel metal hydride battery (13), and a radiator (22, 31) that communicates with the inside of the sealed case (10). Refrigerant is filled in a refrigerant system path including a closed circuit including the sealed case (10) and the radiators (22, 31) , and the refrigerant absorbs heat from the battery (13) inside the sealed case (10). The battery (13) is cooled by evaporating, and the evaporated gas refrigerant dissipates heat in the radiator (22, 31) and condenses, and the condensed liquid refrigerant flows into the sealed case. Further, the adsorbing member (21) that selectively adsorbs hydrogen gas generated from the battery (13) is provided in a gas region where the gas refrigerant flows or the gas refrigerant collects in the refrigerant system. Yes.
[0008]
According to this, when taking away the latent heat of vaporization of the refrigerant from the battery (13) and cooling the battery (13), the refrigerant is directly applied to almost the entire surface of the battery (13) in the internal space of the sealed case (10). Because it is in contact with, the cooling effect is great.
Moreover, since the hydrogen gas can be selectively adsorbed by the adsorbing member (21) provided in the gas region of the refrigerant system path, the accumulation of hydrogen gas, which is a non-condensable gas, in the refrigerant system path is prevented. It is possible to prevent the battery cooling effect from being lowered by gas. In addition, it is possible to eliminate the danger that hydrogen gas accumulated in the refrigerant system passage is released at a time during maintenance and inspection.
[0009]
According to the second aspect of the present invention, a sealed case (10) that houses a nickel metal hydride battery (13), a radiator (22) that communicates with the inside of the sealed case (10 ), and a sealed case (10 ) And the radiator (22), the gas side communication pipe (20) constituting the flow path of the gas refrigerant, the sealed case (10), and the radiator (22) are communicated, and the liquid refrigerant A liquid side communication pipe (23) constituting a flow path, and in a refrigerant system path including a sealed case (10) , a radiator (22) , a gas side communication pipe (20), and a liquid side communication pipe (23). The refrigerant is filled, and the radiator (22) is disposed above the liquid refrigerant inside the sealed case (10), and absorbs heat from the battery (13) inside the sealed case (10). the refrigerant evaporates, the gas side the evaporated gas refrigerant at natural convection Rises a through pipe (20) flows into the radiator (22), gas refrigerant is cooled in the radiator (22) condensed, lower the liquid side communication pipe The condensed liquid refrigerant in the self-weight (23) and it is adapted to reflux the battery (13) near the inside the sealed casing (10), further, the adsorption member (21) of the gas side communication pipe which selectively adsorb hydrogen gas generated from the battery (13) (20) is provided.
[0010]
According to this, the battery (13) can be satisfactorily cooled by the thermosyphon cooling device. Further, hydrogen gas can be adsorbed by the adsorbing member (21) as in the first aspect.
According to a third aspect of the present invention, the inside of the sealed case (10) containing the nickel metal hydride battery (13) is connected to a passage through which the low-pressure side refrigerant of the refrigeration cycle flows, and the low-pressure side refrigerant is connected to the battery ( 13) which absorbs heat and evaporates, and further includes a gas region in which the gas refrigerant in the sealed case (10) collects , and either in the gas region in which the gas refrigerant flows in the refrigeration cycle or in which the gas refrigerant collects. And an adsorption member (21) for selectively adsorbing hydrogen gas generated from the battery (13).
[0011]
According to this, the temperature difference between the battery (13) and the refrigerant can be increased by using the low-temperature refrigerant of the air-conditioning refrigeration cycle, and the cooling performance can be remarkably improved. Hydrogen gas can be adsorbed by the adsorbing member (21) as in the first and second aspects.
The adsorbing member (21) can be constituted by using an adsorbent (21a) made of zeolite or a hydrogen storage alloy as described in claim 4.
[0012]
Moreover, the heat radiator (22) of the invention described in claim 2 can be constituted by an air-cooled heat exchanger that exchanges heat with air to cool and condense the gas refrigerant as in claim 5. According to this, the gas refrigerant can be cooled well by the air cooling method by forced air blowing,
Further, the invention according to claim 6 includes a sealed case (10) for housing the nickel metal hydride battery (13), and a radiator (22, 31) communicating with the inside of the sealed case (10), Refrigerant is filled in a refrigerant system path including a closed circuit including the sealed case (10) and the radiators (22, 31) , and the refrigerant absorbs heat from the battery (13) inside the sealed case (10). The battery (13) is cooled by evaporating, and the evaporated gas refrigerant dissipates heat in the radiator (22, 31) and condenses, and the condensed liquid refrigerant flows into the sealed case. Furthermore, a permeation member (26) that selectively permeates hydrogen gas generated from the battery (13) is provided in a gas region in the refrigerant system where gas refrigerant flows or gas refrigerant collects , and transmits hydrogen gas. Refrigerant through member (26) It is characterized by releasing to the outside of the road.
[0013]
According to this, the latent heat of vaporization of the refrigerant is taken from the battery (13), and the battery (13) can be cooled well, and the hydrogen gas generated from the battery (13) is released out of the refrigerant system path through the permeable member (26). Therefore, hydrogen gas does not accumulate in the refrigerant system path, and problems such as a decrease in cooling effect due to accumulation of hydrogen gas in the refrigerant system path can be reliably prevented.
[0014]
Further, if the heating means (26c) for heating the permeable member (26) is provided as in the seventh aspect of the invention, the amount of hydrogen gas permeated by the permeable member (26) can be increased. Therefore, even if the generation amount of hydrogen gas increases under the severe use conditions of the battery (13), hydrogen gas can be permeated accordingly.
The transmissive member (26) can be configured using a tubular body (26b) made of palladium as described in claim 8.
[0015]
In addition, the code | symbol in the parenthesis attached | subjected to each said means shows the correspondence with the specific means of embodiment description later mentioned.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a first embodiment. A sealed case 10 includes a case body 11 and an upper lid 12 that airtightly closes an upper opening end of the case body 11. Here, the case main body 11 and the upper lid 12 are formed of an appropriate metal or resin, and the overall shape thereof is a vertically long cylinder or polygonal shape in the vertical direction.
[0017]
A battery 13 serving as an in-vehicle power source is accommodated in the sealed case 10. Output wirings 14 and 15 are electrically connected to the positive and negative terminals 13a and 13b of the battery 13, respectively.
Sealing terminals 16 and 17 are hermetically sealed in the upper lid 12 in a hermetic seal structure, and the output wirings 14 and 15 can be electrically connected to external electrical wiring of the sealing case 10 through the sealing terminals 16 and 17. It has become. Therefore, the power of the battery 13 can be taken out from the sealed terminals 16 and 17.
[0018]
The battery 14 is a rechargeable secondary battery (storage battery), specifically a nickel metal hydride battery. In this nickel metal hydride battery, when the battery temperature becomes high (for example, 45 ° C. or higher), the hydrogen gas generated inside the battery cannot be absorbed inside the battery, and the internal pressure increases. Therefore, a relief valve 18 that opens when the battery internal pressure rises to a predetermined value is provided at the top of the battery 13. The relief valve 18 is configured such that when the battery internal pressure rises to a predetermined value, the valve body (not shown) is displaced against the spring force of the spring means (not shown) to open the inside of the battery 13 to the outside. It is.
[0019]
Incidentally, an opening 19 is opened at the center of the upper lid 12, and the gas side communication pipe 20 is connected to the opening 19 so as to rise upward. An adsorption member 21 described later is disposed in the middle of the gas side communication pipe 20. The gas side communication pipe 20 is connected to one end side of the radiator 22, and the other end side of the radiator 22 is opened near the bottom of the case body 11 of the sealed case 10 via the liquid side communication pipe 23. 24.
[0020]
Therefore, the inside of the sealed case 10 and the radiator 22 constitute a refrigerant system path composed of one closed circuit communicated via the gas side communication pipe 20 and the liquid side communication pipe 23. Is filled with a refrigerant as a working fluid of the thermosyphon cooling device and enclosed. As this refrigerant, a nonflammable low boiling point refrigerant such as florinate is used. In the inside of the sealed case 10, A indicates the liquid level of the refrigerant. In order to improve the circulation of the refrigerant between the sealed case 10 and the radiator 22, the radiator 22 is located above the refrigerant liquid level A. It is arranged on the upper side.
[0021]
Both the communication pipes 20 and 23 can be formed of a metal such as aluminum or a resin, and the radiator 22 has a tube 22a made of a metal such as aluminum having excellent heat conductivity and corrosion resistance. A plate-like fin member 22b is provided for promoting the transfer of heat between the refrigerant inside the tube 22a and the cooling air. The fin member 22b is also made of a metal such as aluminum.
[0022]
The radiator 22 of the present example is configured as an air cooling system that performs heat exchange with air (outside air) blown by the blower 25. The blower 25 includes a drive motor 25a and a blower fan 25b that is rotationally driven by the motor 25a.
The adsorbing member 21 includes an adsorbent 21a that selectively adsorbs hydrogen gas generated from the battery 13 in a case 21b. Here, the adsorbent 21a is made of, for example, granular zeolite.
[0023]
Next, the operation of the above configuration will be described. When the temperature of the battery 13 rises due to a chemical reaction of the battery 13 or Joule loss at the time of discharging, the liquid refrigerant filled in the internal space of the sealed case 10 is quickly discharged from the battery 13. It absorbs heat to boil and gasifies.
Therefore, the battery 13 can be cooled by taking the latent heat of vaporization of the refrigerant from the battery 13. Moreover, since the refrigerant is in direct contact with almost the entire surface of the battery 13 in the internal space of the sealed case 10, the cooling effect is great. Then, the refrigerant gasified in the internal space of the sealed case 10 moves up the gas side communication pipe 20 by natural convection due to a decrease in density, passes through the case 21 b of the adsorption member 21, and flows into the radiator 22. In the radiator 22, the gas refrigerant is cooled and condensed by exchanging heat with the air (outside air) blown by the blower 25. The condensed liquid refrigerant descends the liquid side communication pipe 23 by its own weight due to the increase in density and returns to the internal space of the sealed case 10 to be used for cooling the battery 13 again.
[0024]
By the way, in the battery 13, in the case of overcharge or the like, the generated gas (hydrogen gas) inside the battery cannot be absorbed and the internal pressure of the battery rises. Therefore, the relief valve 18 is opened and the hydrogen is discharged to the outside of the battery 13. Gas may leak out.
However, according to the present embodiment, the adsorption member 21 is disposed in the middle of the gas side communication pipe 20, and the adsorbent 21a provided in the adsorption member 21 has a molecular sieving function like zeolite. A molecule such as fluorinate having a large molecular diameter does not adsorb, and a molecule having a small molecular diameter such as hydrogen gas can be selectively captured. As a result, it is possible to prevent hydrogen gas from accumulating in the refrigerant system path, so that even if the inside of the sealed case 10 is opened at the time of maintenance and inspection due to electrode deterioration of the battery 13, a large amount of hydrogen gas or the like is generated at once. It is not released into the atmosphere.
[0025]
In addition, hydrogen gas has a very low boiling point compared to Fluorinert, which is a refrigerant of a thermosyphon type cooling device, and hydrogen gas acts as a non-condensable gas in the refrigerant system path of the thermosyphon type cooling device. When the hydrogen gas is released into the refrigerant gas 10 and the amount of the hydrogen gas in the refrigerant system increases, the cooling effect of the battery is reduced. However, according to the present embodiment, the adsorbing member 21 absorbs the hydrogen gas. Such problems can be avoided, and the cooling effect of the battery can be maintained well over a long period of time.
[0026]
On the other hand, by using a low boiling point refrigerant such as florinate as the refrigerant of the thermosyphon cooling device, the internal pressure (working fluid pressure) of the sealed case 10 is lowered, and the low strength design of the sealed case 10 is realized. The cost of the sealed case 10 can be reduced. Specifically, the working pressure of florinate is 35 to 70 kPa (about 1/2 of atmospheric pressure), and the boiling point is about 56 ° C.
[0027]
In addition, since low boiling point refrigerants such as florinate are nonflammable, the risk of ignition against leakage of gas generated in the battery 13 can be avoided, and safety can be improved.
(Second Embodiment)
FIG. 2 shows a second embodiment, in which a permeation member 26 that selectively permeates hydrogen gas generated from the battery 13 is installed instead of the adsorption member 21 in the first embodiment.
[0028]
That is, the permeation member 26 uses palladium that is excellent in hydrogen permeability, and a case 26 a communicating with the inside of the pipe 20 is installed on the upper side of the gas side communication pipe 20. A tubular body 26b is disposed so as to penetrate the inside. The tubular body 26b is made of palladium, and both ends thereof are open to the atmosphere outside the case 26a.
[0029]
According to the second embodiment, the hydrogen gas mixed in the refrigerant path flows into the case 26a located at the uppermost part of the refrigerant path. Since palladium constituting the tubular body 26b is excellent in hydrogen permeability, it does not permeate the refrigerant, such as fluorinate, but selectively permeates only hydrogen gas. Can be discharged.
[0030]
(Third embodiment)
FIG. 3 shows a third embodiment, which implements the second embodiment more effectively. Paying attention to the fact that palladium has the property of improving hydrogen permeability when heated to a high temperature, an electric heater 26c as a heating means is additionally installed in the permeable member 26.
[0031]
According to the third embodiment, the permeation amount of hydrogen gas can be increased by energizing the electric heater 26c and heating the tubular body 26b made of palladium to a high temperature. Therefore, even when the amount of generated hydrogen gas is large as in the severe usage environment of the battery 13, the amount of hydrogen gas permeating through the tubular body 26b made of palladium is increased, and hydrogen remains in the refrigerant system path. Can be prevented.
[0032]
In addition, you may use the hot water pipe etc. which warm water circulates as a heating means instead of the electric heater 26c.
(Fourth embodiment)
FIG. 4 shows a fourth embodiment. In the first to third embodiments described above, the method of cooling the battery 13 with the thermosyphon cooling device has been described. However, the fourth embodiment is a refrigeration cycle for vehicle air conditioning. The battery 13 is configured to be cooled by the cold heat of the low-pressure side refrigerant.
[0033]
In FIG. 4, the compressor 30 compresses and discharges the refrigerant (for example, HFC-134a) of the refrigeration cycle, and the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 30 is cooled by the condenser 31 and condensed. To do. The condensed refrigerant is gas-liquid separated by the liquid receiver 32, and the liquid refrigerant is depressurized by the temperature type expansion valve (decompression unit) 33 to a low-temperature low-pressure gas-liquid two-phase refrigerant. Then, this gas-liquid two-phase refrigerant absorbs heat from the conditioned air blown by an air conditioner blower (not shown) in the evaporator 34, evaporates and gasifies, and the gas refrigerant is sucked into the compressor 30 and again. , Compressed.
[0034]
For such a vehicle air conditioning refrigeration cycle, in the battery cooling device of the fourth embodiment, the battery 13 is housed in a refrigerant passage between the downstream side of the temperature type expansion valve 33 and the upstream side of the evaporator 34. Case 10 is installed. Of the gas-liquid two-phase refrigerant decompressed by the temperature type expansion valve 33, a liquid refrigerant region B in which liquid refrigerant accumulates is formed on the lower side inside the sealed case 10, and the gas inside the sealed case 10 has an air The gas refrigerant of the liquid two-phase refrigerant gathers to form a gas region C.
[0035]
The lower side of the battery 13 is arranged so as to be immersed in the liquid refrigerant region B inside the sealed case 10. In the example shown in FIG. 4, the adsorbing member 21 that adsorbs hydrogen gas is disposed on the inner surface of the upper lid 12 of the sealed case 10, and the adsorbing member 21 is positioned in the gas region C inside the sealed case 10. .
According to the fourth embodiment, the low-temperature and low-pressure gas-liquid two-phase refrigerant decompressed by the temperature type expansion valve 33 in the vehicle air-conditioning refrigeration cycle flows into the sealed case 10, where a part of the low-pressure side liquid refrigerant Absorbs heat from the battery 13 and evaporates. Therefore, the battery 13 can be cooled by the latent heat of vaporization of the refrigerant. Here, as the cooling medium for cooling the battery 13, a low-temperature refrigerant of the air-conditioning refrigeration cycle is used, so a very large temperature difference can be set between the battery 13 and the low-temperature refrigerant, and the cooling capacity of the battery 13 can be increased. It can be improved dramatically.
[0036]
When the vehicle air conditioning refrigeration cycle is configured as a heat pump, during the winter heating, the refrigerant on the refrigeration cycle side absorbs heat inside the sealed case 10 to recover waste heat, thereby heating in the winter. Ability can be increased. Of the refrigerant that has passed through the sealed case 10, the remaining liquid refrigerant evaporates in the air conditioning evaporator 34 to cool the conditioned air.
[0037]
On the other hand, the hydrogen gas generated from the battery 13 in the sealed case 10 is selectively adsorbed by the adsorbing member 21 installed in the gas region C above the sealed case 10.
In addition, in 4th Embodiment, although the adsorption member 21 is installed in the gas area C above the inside of the airtight case 10, if the adsorption member 21 is a gas area, it can exhibit the adsorption action of hydrogen gas anywhere, and adsorption The member 21 can be installed in a gas region outside the sealed case 10, that is, in the suction side portion D of the compressor 30, the discharge side portion E of the compressor 30, the gas region F inside the liquid receiver 32, and the like. In short, the adsorbing member 21 may be installed anywhere within the refrigeration cycle.
[0038]
In each of the above embodiments, zeolite is used as the adsorbent 21a of the adsorbing member 21, but in addition to zeolite, any adsorbent can be used as long as it can adsorb a large amount of hydrogen gas, such as a hydrogen storage alloy. 21a can be used.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an entire system showing a first embodiment of the present invention.
FIG. 2 is a configuration diagram of an entire system showing a second embodiment of the present invention.
FIG. 3 is a main part configuration diagram showing a third embodiment of the present invention;
FIG. 4 is a refrigeration cycle diagram showing a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Sealed case, 13 ... Battery, 21 ... Adsorption member, 22 ... Radiator,
26 ... Permeation member, 33 ... Temperature type expansion valve, 34 ... Evaporator.

Claims (8)

A sealed case (10) for housing a nickel metal hydride battery (13) ;
A radiator (22, 31) communicating with the inside of the sealed case (10),
A refrigerant is filled in a refrigerant system path including a closed circuit including the sealed case (10) and the radiator (22, 31) ,
The refrigerant absorbs heat from the battery (13) and evaporates inside the sealed case (10) to cool the battery (13), and the evaporated gas refrigerant is transferred to the radiator (22, 31). Heat is condensed by condensation, and the condensed liquid refrigerant flows into the sealed case .
Further, characterized in that the suction member (21) which selectively adsorb hydrogen gas generated from the battery (13), through which gas refrigerant of the refrigerant pathways, or, with the gas zone in which the gas refrigerant is collected Battery cooling device. A sealed case (10) for housing a nickel metal hydride battery (13);
A radiator (22) communicating with the inside of the sealed case (10) ;
A gas-side communication pipe (20) that communicates the sealed case (10) and the radiator (22) to form a flow path of a gas refrigerant;
A liquid side communication pipe (23) that communicates the sealed case (10) and the radiator (22) to form a liquid refrigerant flow path ;
Refrigerant is filled in a refrigerant system path including the sealed case (10) , the radiator (22) , the gas side communication pipe (20), and the liquid side communication pipe (23) ,
The radiator (22) is disposed above the liquid refrigerant inside the sealed case (10),
Inside the sealed case (10), heat is absorbed from the battery (13) and the refrigerant evaporates, and the evaporated gas refrigerant rises up the gas side communication pipe (20) by natural convection and the radiator ( 22), the gas refrigerant is cooled and condensed by the radiator (22), and the condensed liquid refrigerant descends the liquid side communication pipe (23) by its own weight, and the inside of the sealed case (10). It is designed to recirculate around the battery (13),
Furthermore, the battery cooling device further comprising an adsorption member (21) for selectively adsorbing hydrogen gas generated from the battery (13) in the gas side communication pipe (20) . The inside of the sealed case (10) containing the nickel-metal hydride battery (13) is connected to a passage through which the low-pressure side refrigerant of the refrigeration cycle flows, so that the low-pressure side refrigerant absorbs heat from the battery (13) and evaporates. West,
Further, the battery (13) is generated in any of the refrigeration cycle including the gas region where the gas refrigerant in the sealed case (10) collects , or in the gas region where the gas refrigerant collects. A battery cooling device comprising an adsorption member (21) that selectively adsorbs hydrogen gas.   The battery cooling device according to any one of claims 1 to 3, wherein the adsorbing member (21) includes an adsorbent (21a) made of zeolite or a hydrogen storage alloy.   The battery cooling device according to claim 2, wherein the radiator (22) is an air-cooled heat exchanger that exchanges heat with air to cool and condense the gas refrigerant. A sealed case (10) for housing a nickel metal hydride battery (13) ;
A radiator (22, 31) communicating with the inside of the sealed case (10),
A refrigerant is filled in a refrigerant system path including a closed circuit including the sealed case (10) and the radiator (22, 31) ,
The refrigerant absorbs heat from the battery (13) and evaporates inside the sealed case (10) to cool the battery (13), and the evaporated gas refrigerant is transferred to the radiator (22, 31). Heat is condensed by condensation, and the condensed liquid refrigerant flows into the sealed case .
Furthermore, the battery (13) transmitting member selectively permeable to hydrogen gas generated from the (26), flows the gas refrigerant of the refrigerant system path or, provided the gas tract where the gas refrigerant is collected, the hydrogen gas A battery cooling device for discharging to the outside of the refrigerant system path through the permeable member (26).   The battery cooling device according to claim 6, further comprising heating means (26c) for heating the transmission member (26).   The battery cooling device according to claim 6 or 7, wherein the transmission member (26) has a tubular body (26b) made of palladium.

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