Patent Application
20240283053
The present invention relates to a battery cooling system, and specifically, relates to a battery cooling system that cools a battery including a plurality of battery packs by a jacket with a branch channel that branches from a main channel and returns to the main channel directly connected to pressure feeding means, such as a pump and a fan, that pressure feeds a cooling medium.
Recently, demand for batteries in power application typified by electric vehicles and power tools is increasing, and in a battery in which battery packs including a plurality of cells are integrated, the heat generation amount of the battery tends to become large due to the large conducting current in the case of the power application. Since use of the battery at high temperature accelerates deterioration, it is necessary to reduce the output from the battery or decrease the charging speed for protecting the battery.
However, since a plurality of battery packs are series-connected, the output or the charging speed needs to be reduced in the whole battery. Therefore, it is necessary to surely cool each of the battery packs by any cooling system to make temperatures of the individual battery packs uniform.
That is, since the battery pack is temperature dependent, and the battery temperature significantly affects the battery life, in the case of a battery of battery packs including a plurality of cells, it is important to attempt making battery temperatures of the respective cells uniform. For cooling the battery and making temperatures uniform, a method in which a flow passage of a cooling medium is provided in a battery pack, and it is driven by an electric pump or an electric fan to flow the cooling medium has been generally used.
For example, Patent Document 1 discloses a battery cooling device for an electric vehicle including a battery (13) for driving the electric vehicle, a cooling member (14) internally including cooling medium flow passages (14a, 14b), a cooling medium supply piping (15) that supplies the cooling medium to the cooling member (14), and a cooling medium discharge piping (16) that discharges the cooling medium from the cooling member (14) (see claim 1 in claims, paragraphs to in Description,
The battery cooling device includes a cooling medium jacket (14) that is integrally formed with a battery case (12) and internally includes the cooling medium flow passages (14a, 14b). The cooling medium supplied from the cooling medium supply piping (15) branches from the cooling medium inlet (20) of the pair of cooling medium jackets (14) positioned at the frontmost position toward the cooling medium supply passages (14a) on the left and right sides, flows outward in the vehicle width direction, makes a U-turn in the communication chambers (23), flows inward in the vehicle width direction in the cooling medium discharge passages (14b) on the left and right sides, is combined in the cooling medium outlet (21), and is returned to the cooling medium discharge piping (16) (see paragraph of Description of Patent Document 1).
In the battery cooling device of Patent Document 1, since the internal diameter d1 of the cooling medium inlets (20) and the cooling medium outlets (21) of the three pairs of cooling medium jackets (14) on the upstream side is set to be small, and the internal diameter d2 of the cooling medium inlets (20) and the cooling medium outlets (21) of the three pairs of cooling medium jackets (14) on the downstream side is set to be large, it is possible by making the amount of cooling medium supplied to the six pairs of cooling medium jackets (14) uniform to evenly cool all of the battery modules (13) (see paragraph of Description of Patent Document 1).
However, in the method of making the flow rate of the cooling medium uniform by the water flow resistance due to the internal diameter, the orifice, or the like, of the cooling medium passage, actually, there is a problem that the flow rate of cooling water flowing into the respective jackets varies due to variation in passage area, bends, and the like. Moreover, actually, there is a problem that variation occurs in temperatures of the respective battery packs because of variation in heat generation amount due to the product error of the battery pack, and it is impossible to make the temperatures of all of the battery packs uniform only by making the water flow resistances uniform.
Patent Document 2 discloses a cooling system that includes a plurality of coolers (30, 31, 32, 33) including heat exchanging units (300, 310, 320, 330) configured to cool batteries by heat exchange between a cooling medium flowing inside and the batteries (20), and a cooling medium supply passage (W20) that supplies the cooling medium to the plurality of coolers (see claim 1 in claims, paragraphs to in Description,
The cooling medium supply passage of the cooling system disclosed in Patent Document 2 is provided with a main flow channel (W21) through which the cooling medium flows and a plurality of branch flow channels (W22a, W22b, W22c, W22d) that branch from the main flow channel (W21) and distribute the cooling medium to the plurality of coolers (30, 31, 32, 33), respectively. With the coolers (30, 31, 32, 33) provided at the plurality of branch flow channels (W22a, W22b, W22c, W22d), respectively, the cooling medium is supplied to the plurality of coolers (30, 31, 32, 33) in parallel.
Then, also in the cooling system disclosed in Patent Document 2, similarly to the battery cooling device of Patent Document 1, when a portion branched from the main flow channel (W21) into the branch flow channels (W22a, W22b, W22c, W22d) at the cooling medium supply passage is assumed as a branching portion (Pb), orifices (301, 311, 321, 331) are provided at portions from the branching portion (Pb) to the heat exchanging units (300, 310, 320, 330) to make the flow rates of the cooling medium uniform by the water flow resistance.
However, in the cooling system disclosed in Patent Document 2, similarly to the battery cooling device of Patent Document 1, the problem that the flow rate of cooling water flowing into the respective jackets varies due to variation in passage area, bends, and the like, and the problem that variation occurs in temperatures of the respective battery packs because of variation in heat generation amount due to the product error of the battery pack have not been solved.
Patent Document 3 discloses a cooling system including a common channel through which a cooling medium flows, a plurality of branch channels that are coupled to the common channel and each supply the cooling medium to one or more cooling targets, and at least one EHD flow rate adjusting device that adjusts amounts of the cooling medium flowing into the respective branch channels (see claim 1 in claims, paragraphs to in Description,
However, the cooling system disclosed in Patent Document 3 is one in which the flow rate of the cooling medium is adjusted with the EHD flow rate adjusting device, and there is a problem that a complicated control is necessary, and the system is unsuitable for a mechanism, such as an electric vehicle, in which vibration possibly causes a malfunction leading to a serious accident because of lack of durability and reliability.
Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a battery cooling system configured to distribute a cooling medium at an appropriate flow rate by increasing and decreasing a flow resistance of the cooling medium corresponding to a heat generation amount of each of battery packs with a mechanism that is low-price, simple, and highly durable and reliable with little malfunction.
A battery cooling system according to a first invention is a battery cooling system for cooling a battery including a plurality of battery packs by a jacket. The jacket includes a branch channel that branches from a main channel and returns to the main channel. The main channel is directly coupled to pressure feeding means that pressure feeds a cooling medium. The battery cooling system includes a temperature control valve provided at the branch channel through which the cooling medium flows out from the channel of the jacket to an outside and returns to the main channel. The self-powered temperature control valve adjusts a degree of opening of a valve corresponding to a temperature of the cooling medium nearby.
In a battery cooling system according to a second invention, which is in the first invention, the temperature control valve is a wax-type thermostat.
In a battery cooling system according to a third invention, which is in the first invention, the temperature control valve is a bellows-type thermostat.
In a battery cooling system according to a fourth invention, which is in the first invention, the temperature control valve is an SMA-type thermostat.
In a battery cooling system according to a fifth invention, which is in any of the first invention to the fourth invention, the temperature control valve is provided with a leak hole.
In a battery cooling system according to a sixth invention, which is in the fifth invention, the leak hole is a leak groove formed at a part of a valve seat or a valve element.
In a battery cooling system according to a seventh invention, which is in any of the first invention to the sixth invention, a pressure relief structure is provided.
According to the first invention to the seventh invention, the flow resistance of the cooling medium can be increased and decreased corresponding to the heat generation amounts of the respective battery packs, and the cooling medium can be distributed at the appropriate flow rate, thus allowing uniformly controlling the battery temperatures of the respective cells. Therefore, the life of the battery pack and the battery can be prolonged and the durability can be improved.
According to the first invention to the seventh invention, since the above-described operational advantage is achieved with the temperature control valve that has been proven for long years as cooling means for internal combustion engines of an automobile and the like in which vibration possibly causes a malfunction leading to a serious accident, one that is low-price, simple, and highly durable and reliable with little malfunction is provided.
Especially, according to the fifth invention, since the leak hole is configured to always flow the cooling medium by a constant amount, and the temperature of the cooling medium is always measured, the temperatures of the individual battery packs can be always monitored.
Especially, according to the sixth invention, even when the leak hole is clogged with a foreign matter, by opening the valve, the foreign matter can be flowed out by the cooling medium and removed.
Especially, according to the seventh invention, since the pressure relief structure is provided, even in a temperature range before opening the valve of the thermostat, the output of the pump that pressure feeds the cooling medium can be increased as necessary to flow the cooling medium.
The following describes a battery cooling system according to the embodiment of the present invention in detail with reference to the drawings.
With reference to
As illustrated in
A water jacket 2 according to the embodiment is, as illustrated in
The water jacket 2 includes a rectangular main body portion formed of a metal plate, and a supply channel and a discharge channel configured to supply the cooling water inside the main body portion. That is, as illustrated in
Then, as illustrated in
However, the temperature control valve according to the present invention is not limited to the wax-type thermostat, and may be a bellows-type thermostat in which an ether is sealed in a stretchable bellows and the ether is expanded and contracted by heat to open and close a valve. The temperature control valve according to the present invention may be a thermostat of another type, for example, an SMA-type thermostat configured to open and close a valve by a shape memory alloy. Basically, the temperature control valve according to the present invention only needs to be a temperature control valve configured to adjust a degree of opening of a valve corresponding to a temperature of a cooling medium nearby.
Next, with reference to
As illustrated in
The wax pellet 6 includes a housing 60 in which a paraffin wax is sealed, and a piston rod 61 configured to freely come in and out with respect to the housing 60. The temperature control valve 5 has a mechanism in which the wax is expanded to cause the piston rod 61 to project and push up a valve element 7 attached to the piston rod 61, thereby opening the valve. It is needless to say that the wax sealed in the wax pellet 6 is not limited to the paraffin wax, and only needs to be a material that is relatively large in volume change and has a predetermined thermal expansion characteristic, for example, a micro wax.
The valve element 7 includes a doughnut-shaped valve body 70 formed of a stainless steel plate as a substrate body, and the valve body 70 has a peripheral portion covered with a sealing material 71 formed of EPDM (ethylene-propylene-diene rubber). As illustrated in
A stainless steel coil spring 8 is interposed between the valve element 7 and the mounting frame 51, and the valve element 7 is biased in a direction of the wax pellet 6 side.
As illustrated in
Accordingly, the valve element 7 fitted to the piston rod 61 is pushed up, the opening amount of the valve increases, and the flow rate of the cooling water increases, thus allowing effectively cooling only the battery pack 3 having the high heat generation amount by the water jacket 2.
As illustrated in
Moreover, with the temperature control valve 5 having the pressure relief structure in which the valve (valve element 7) opens to release the pressure when the pressure applied to the valve element 7 becomes a predetermined value or more, even in a temperature range before opening the valve of the thermostat, the output of the pump that pressure feeds the cooling medium can be increased as necessary to flow the cooling medium.
While the case where the fitting portion of the valve element 7 comes off from the piston rod 61 is described as the pressure relief structure of the temperature control valve 5, another pressure relief structure that the pressure is released when a pressure of certain degree or more is applied to the valve element 7, for example, the valve element 7 is deformed by the pressure and pressed to be opened, may be employed.
According to the battery cooling system 1 described above, by opening and closing the temperature control valve 5, the flow resistance of the cooling medium can be increased and decreased corresponding to the beat generation amounts of the respective battery packs 3, and the cooling medium can be distributed at the appropriate flow rate, thus allowing uniformly controlling the battery temperatures of the respective cells. Therefore, the life of the battery pack 3 and the battery can be prolonged and the durability can be improved.
According to the battery cooling system 1, since the above-described operational advantage is achieved with the temperature control valve that has been proven for long years as cooling means for internal combustion engines of an automobile and the like in which vibration possibly causes a malfunction leading to a serious accident, one that is low-price, simple, and highly durable and reliable with little malfunction can be provided.
In addition, according to the battery cooling system 1, since the temperature control valve 5 has the pressure relief structure in which the valve (valve element 7) opens to release the pressure when the pressure applied to the valve element 7 becomes a predetermined value or more, even in a temperature range before opening the valve of the thermostat, the output of the pump that pressure feeds the cooling medium can be increased as necessary to flow the cooling medium.
Next, with reference to
The wax pellet 6′ includes, similarly to the wax pellet 6, a housing 60′ in which a paraffin wax is sealed, and a piston rod 61′ configured to freely come in and out with respect to the housing 60′. However, different from the temperature control valve 5, the temperature control valve 5′ has a mechanism in which the expansion of the wax projects the piston rod 61′ to push down the valve element 7′ fitted to the housing 60′, thereby opening the valve. It is needless to say that the wax sealed in the wax pellet 6′ is also not limited to the paraffin wax, and only needs to be a material that is relatively large in volume change and has a predetermined thermal expansion characteristic, for example, a micro wax.
The valve element 7′ includes a doughnut-shaped valve body 70′ formed of a stainless steel plate, and the valve body 70′ is drilled with a leak hole 72′ for flowing the cooling water as a cooling medium by a small amount (predetermined amount) enough to measure the temperature even when the valve is closed. Therefore, according to the battery cooling system 1 including the temperature control valve 5′ of the second embodiment mounted to the discharge branch channel 13, the leak hole 72′ allows the cooling water to always flow through the discharge branch channel 13 by a constant amount even when the valve of the temperature control valve 5′ is closed. Accordingly, according to the battery cooling system 1 including the temperature control valve 5′, the temperatures of the respective battery packs 3 can be always monitored by always measuring the temperature of the cooling water that has passed through the battery pack 3.
The valve element 7′ may be covered with a rubber material, such as EPDM (ethylene-propylene-diene rubber) similarly to the above-described valve element 7.
As illustrated in
Next, with reference to
The valve element 7″ of the temperature control valve 5″ according to the third embodiment includes a doughnut-shaped valve body 70″ formed of a stainless steel plate, and the valve body 70″ is provided with, instead of the leak hole 72′, a leak groove 72″ formed by partially notching a part of the valve body 70′ to flow the cooling water by a predetermined amount even when the valve is closed. Therefore, according to the battery cooling system 1 including the temperature control valve 5″ of the third embodiment mounted to the discharge branch channel 13, the leak groove 72″ allows always monitoring the temperatures of the respective battery packs 3 by flowing the cooling water even when the valve of the temperature control valve 5″ is closed and always measuring the temperature of the cooling water that has passed through the battery pack 3. Moreover, according to the battery cooling system 1 including the temperature control valve 5″, even when the leak groove 72″ is clogged with a foreign matter, by opening the temperature control valve 5″ to open the valve element 7″, the foreign matter can be flowed out by the cooling water and removed from the leak groove 72″.
Needless to say, the valve element 7″ may be covered with a rubber material, such as EPDM (ethylene-propylene-diene rubber) similarly to the above-described valve element 7.
Instead of forming the leak groove 72″ at the valve element 7″, a leak groove may be formed by notching a part of a valve seat side, that is, the cap 51′ or the case 50′ in the illustrated configuration, with which the valve element 7″ is brought in close contact for the closure. This is because also in this case, the cooling water can be flowed even when the valve is closed, and a foreign matter can be flowed out by the cooling water and removed when the valve is opened.
While the battery cooling system 1 according to the embodiments of the present invention and the temperature control valves 5 to 5″ according to the first embodiment to the third embodiment have been described above in detail, the described or illustrated embodiments each merely indicate one embodiment embodied in carrying out the present invention. Accordingly, the technical scope of the present invention should not be interpreted in a limited way through the embodiments. Especially, while the cooling water is described as an example of the cooling medium, obviously, the cooling medium only needs to include a fluid having an appropriate thermal capacity enough to cool the battery pack.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-043228 | Mar 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/048137 | 12/27/2022 | WO |
