Cooling device for battery stack

Abstract

To remove dust or abnormalities remaining near the entrance of a flow passage 5 between cells in a cooling device 1 which circulates cooling air from an entrance port 3 to flow passages 5 among cells separately of a battery stack formed by laminating a plurality of battery cells 2.SOLUTION: A cooling device for a battery stack includes: an inlet port side switching valve 8 for selectively closing one of a connection flow passage and a discharge port before branch from an inlet port to an inter-cell flow passage 5 so that cooling air is flown from the inlet port 3 for causing cooling air to enter a battery stack through the inter-cell flow passage to an exit port 4 when a battery stack is being used and cooling air is passed through a bypass flow passage 7 connecting from the inlet port to the exit port by avoiding the inter-cell flow passage, is circulated through the inter-cell flow passage 5 from the exit port 4 side to the inflow port 3 side, and is discharged from a discharge port 6 when the battery stack is not being used; and an exit port side switch valve 9 for selectively closing one of the exit end and the exit port of the bypass flow passage connecting to the exit port.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling device for a battery stack consisting of a plurality of stacked battery cells, and more specifically to a structure for removing dust and foreign matter from within a flow path in an air-cooled battery stack cooling device. [Background technology]

[0002] A structure for cooling battery cells is provided in a large-capacity battery stack or battery module used in electric vehicles, etc. For example, Patent Document 1 proposes a configuration in which a battery pack in which multiple battery modules are stacked has refrigerant passages between the battery modules through which a refrigerant flows, and an intake chamber and an exhaust chamber on the upstream and downstream sides of the refrigerant passages, through which the refrigerant flows, to suppress variations in battery temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2007-299638 Summary of the Invention [Problem to be solved by the invention]

[0004] As one of the structures or devices for cooling a battery stack formed by stacking a plurality of battery cells, as disclosed in Patent Document 1, typically, as illustrated in FIG. 2, a configuration is adopted in which a plurality of battery cells 2 in a battery module 1 are stacked in their thickness direction, and the cooling air I flowing in from an inlet 3 branches into flow paths 5 (inter-cell flow paths) formed between the cells 2, absorbs heat from each cell 2 while passing through each inter-cell flow path 5, and is then collected at an outlet 4 and discharged (o). In this configuration, the area of ​​each flow path is narrow in the vicinity of the inlet 5a where the inlet 3 branches into the inter-cell flow paths 5, so that the pressure loss of the circulating cooling air increases and the flow rate decreases, and as a result, dust and foreign matter arriving with the cooling air tends to be left behind in the vicinity of the inlet 5a and adhere to and accumulate on the wall surface of the flow path. If dust and foreign matter remain in the vicinity of the inlet 5a in this way, the cooling performance of the battery cells will decrease.

[0005] In view of the above circumstances, a primary object of the present invention is to provide a configuration for removing dust and foreign matter that may accumulate near the inlets of the flow paths between each cell in a cooling device for a battery stack made up of multiple stacked battery cells, in which cooling air is branched from an inlet to flow paths formed between each cell. [Means for solving the problem]

[0006] According to the present invention, the above problem is solved by a cooling device for a battery stack formed by stacking a plurality of battery cells, an inlet for introducing cooling air into the battery stack; an inter-cell flow passage through which the cooling air flows, the inter-cell flow passage being formed so as to branch from the inlet and extend between each of the battery cells; an outlet through which the cooling air from the inter-cell flow passages is joined and discharged; and a bypass flow path that is connected from the inlet to the outlet by bypassing the inter-cell flow path; an exhaust port that exhausts the cooling air to the outside between the inlet and the inlet of the inter-cell flow path; an inlet side switching valve that selectively closes one of a connection flow path before branching from the inlet to the inter-cell flow path and the outlet; an outlet side switching valve that selectively closes one of an outlet end of the bypass flow path connected to the outlet and the outlet; a switching valve control means for controlling the states of the inlet side switching valve and the outlet side switching valve; having This is achieved by a device configured such that, during use of the battery stack, the switching valve control means causes the inlet side switching valve to close the exhaust outlet and the outlet side switching valve to close the outlet end of the bypass flow path, so that the cooling air flows from the inlet directly to each of the inter-cell flow paths and flows out from the outlet, and when use of the battery stack is stopped, the switching valve closes the inlet side switching valve and closes the outlet, so that the cooling air passes from the inlet to the bypass flow path, and then flows through each of the inter-cell flow paths from the outlet side to the inlet side, and flows out from the exhaust.

[0007] In the above configuration, the "battery cell" may be any type of battery cell normally used in this field, and the "battery stack" may be configured in a normal manner. The "cooling air" may typically be air blown from a blower. The inlet, inter-cell flow paths, outlet, bypass flow paths, and exhaust port may be made of materials normally used in this field that allow the cooling air to flow. The inlet-side switching valve and the outlet-side switching valve may each be any type of valve device in which a valve body is operated by an actuator or the like to a position that selectively closes one flow path and opens the other flow path under the control of a switching valve control means. The switching valve control means may be a computer device and may be realized by operation according to a program.

[0008] In the above-mentioned configuration of the present invention, a bypass flow path, an inlet-side switching valve, an outlet-side switching valve, an exhaust port, and a switching valve control means are provided in the configuration of the battery stack cooling device as illustrated in Fig. 2. During use of the battery stack, which requires cooling of the battery stack, cooling air is taken in from the inlet, flows directly into the inter-cell flow paths, and flows out from the outlet port, as in the case of Fig. 2. Meanwhile, when the battery stack is not in use, the cooling air taken in from the inlet passes through the bypass flow path, passes through the inter-cell flow paths from the outlet side to the inlet side, i.e., in the opposite direction to when the battery stack is in use, and flows out from the exhaust port provided near the inlet. According to this configuration, by passing the cooling air through the inter-cell flow paths in the opposite direction to normal, dust and foreign matter remaining near the inlets of the inter-cell flow paths is pushed toward the exhaust port, and thus dust and foreign matter remaining near the inlets of the flow paths between the cells is removed.

[0009] In the device of the present invention, when the battery stack is stopped from being used, the process of passing the cooling air through the inter-cell flow passages in a direction opposite to the normal direction may be performed for a predetermined time period that is arbitrarily set immediately after the battery stack is stopped from being used. At that time, the output of the blower that blows the cooling air may be maximized, thereby removing as much dust and foreign matter as possible that has accumulated near the inlets of the flow passages between the cells. Effect of the Invention

[0010] Thus, according to the battery stack cooling device of the present invention, when the battery stack is not in use, the cooling air flows in the inter-cell flow paths in the opposite direction to when the battery stack is in use, so that dust and foreign matter that accumulates near the inlets of the inter-cell flow paths branching off from the inlet while the battery stack is in use is swept away by the reverse flowing cooling air and removed from near the inlets of the inter-cell flow paths. With this configuration, dust and foreign matter are removed from near the inlets of the inter-cell flow paths every time the battery stack is stopped, so that it is possible to avoid a reduction in the cooling effect due to the accumulation of dust and foreign matter near the inlets of the inter-cell flow paths, and it is expected that performance deterioration of the battery cells will be avoided. The device of the present invention may be applied to the structure of a battery stack in an electric vehicle or other machinery or equipment.

[0011] Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention. [Brief description of the drawings]

[0012] [Figure 1] 1(A) and (B) are schematic diagrams illustrating the configuration of the device for explaining the operation of the present embodiment, in which (A) shows the state in which the battery stack is in use (during cooling), and (B) shows the state in which dust and the like is removed near the inlet of the inter-cell flow path when the battery stack is not in use. [Diagram 2] FIG. 2 is a schematic diagram of a conventional battery stack cooling device. [Explanation of symbols]

[0013] Reference Signs List 1: Battery stack cooling device, 2: Battery cell, 3: Inlet, 4: Outlet, 5: Inter-cell flow path, 7: Coolant circulation path, 6: Outlet, 7: Bypass flow path, 7a: Bypass flow path inlet end, 7b: Bypass flow path outlet end, 8: Inlet side switching valve, 9: Outlet side switching valve, 10: Switching valve control device BEST MODE FOR CARRYING OUT THEINVENTION

[0014] The present invention will now be described in detail with reference to some preferred embodiments thereof with reference to the accompanying drawings, in which like reference numerals indicate like parts.

[0015] Device configuration 1(A) and (B), in a battery stack to which this embodiment is applied, similarly to the case of Fig. 2, a cooling device 1 is provided in a configuration in which a plurality of battery cells 2 are stacked in their thickness direction, with an inlet 3 for taking in cooling air, a plurality of inter-cell flow paths 5 branching from the inlet 3 and formed between the cells 2, and an outlet 4 where the inter-cell flow paths 5 join and through which the cooling air flows out. The cooling air sent to the inlet 3 may be generated by a blower (not shown). In this embodiment, further structures for removing dust and foreign matter remaining near the inlet 5a of the inter-cell flow passage 5 include a bypass flow passage 7 that circulates cooling air from the inlet 3 to just before the outlet 4, bypassing the inter-cell flow passage 5, an exhaust outlet 6 that discharges cooling air between the inlet 3 and the inter-cell flow passage 5, an inlet-side switching valve 8 that selectively closes one of the connecting flow passage 3a before branching from the inlet 3 to the inter-cell flow passage 5 and the exhaust outlet 6, an outlet-side switching valve 9 that selectively closes one of the outlet 4 and the outlet end 7b of the bypass flow passage 7, and a switching valve control device 10 that controls the states of the switching valves 8, 9.

[0016] In this configuration, as can be seen from the figure, the bypass flow passage 7 is formed so that its inlet end 7a opens just before the connecting flow passage 3a before branching from the inlet 3 to the inter-cell flow passage 5, and its outlet end 7b opens between the inter-cell flow passage 5 and the outlet 4, bypassing the inter-cell flow passage 5. The exhaust port 6 is formed so that cooling air can flow out between the connecting flow passage 3a and the inter-cell flow passage 5. Note that, as shown in the figure, it is preferable that the installation positions of the exhaust port 6 and the outlet end 7b are set to be shifted from the position of the inter-cell flow passage 5 so as not to overlap in the extension direction of the inter-cell flow passage 5 (if the exhaust port 6 and the outlet end 7b overlap with any of the inter-cell flow passages 5 in the extension direction of the inter-cell flow passage 5, only that inter-cell flow passage 5 will have a low pressure loss, which may cause a decrease in the flow rate of the other inter-cell flow passages 5). As described above, the inlet-side switching valve 8 is a switching valve that selectively closes one of the connection flow path 3a and the discharge port 6, and is provided so that the valve body is displaced by an actuator (not shown) to close one of the connection flow path 3a and the discharge port 6 and open the other. As described above, the outlet-side switching valve 9 is a switching valve that selectively closes one of the outlet 4 and the outlet end 7b of the bypass flow path 7, and is provided so that the valve body is displaced by an actuator (not shown) to close one of the outlet 4 and the outlet end 7b of the bypass flow path 7 and open the other. The switching valve control device 10 may be realized by a computer device that operates according to a program, and in this embodiment, may be configured to send control commands to the actuators of the inlet-side switching valve 8 and the outlet-side switching valve 9 in a manner described later, by referring to information on the operating state of the battery obtained from a control device (not shown) that controls the operation of the battery.

[0017] Operation of the device In the operation of the device of this embodiment described above, while the battery stack is in use, for example, while the ignition switch is ON in a vehicle, as shown in FIG. 1(A), the inlet-side switching valve 8 is controlled to close the exhaust outlet 6, and the outlet-side switching valve 9 is controlled to close the outlet end 7b of the bypass flow path 7, so that the cooling air I flowing in from the inlet 3 passes through the connecting flow path 3a (since the outlet end 7b is closed, no cooling air flows in the bypass flow path 7), passes through the inter-cell flow path 5, where it absorbs heat from the cells 2, and then joins together and flows out from the outlet 4 (o). On the other hand, when the use of the battery stack is stopped, specifically, for example, when the ignition switch is turned OFF in a vehicle, as illustrated in Fig. 1(B), the inlet-side switching valve 8 is controlled to close the connecting flow path 3a and open the exhaust port 6, and the outlet-side switching valve 9 is controlled to open the outlet end 7b of the bypass flow path 7 and close the exhaust port 4. This forms a route for cooling air to flow from the inlet 3 through the bypass flow path 7 through the inter-cell flow paths 5 in the opposite direction to when the battery stack is in use, and flow out from the exhaust port 6. Here, cooling air is generated by a blower, and the cooling air is circulated through the inter-cell flow paths 5 in the opposite direction to when the battery stack is in use. As a result, if dust or foreign matter is present near the inlet 5a of the inter-cell flow paths 5 during use of the battery stack, the dust or foreign matter is swept away by the cooling air flowing in the opposite direction through the inter-cell flow paths 5, and flows out from the exhaust port 6. The process of flowing cooling air in the reverse direction through the inter-cell flow passages 5 after the battery stack is stopped may be performed for a period that may be set appropriately. During that period, the blower may be controlled to blow cooling air at its maximum output.

[0018] The states of the inlet side switching valve 8 and the outlet side switching valve 9 may be controlled by the switching valve control device 10 referring to battery operation information and giving control commands to the actuators of the inlet side switching valve 8 and the outlet side switching valve 9, so that the actuators operate to achieve the above states. When the blower is stopped and the process of flowing cooling air in the reverse direction through the inter-cell flow paths 5 is completed, the states of the inlet side switching valve 8 and the outlet side switching valve 9 may be returned to the states when the battery stack was in use.

[0019] Thus, in the configuration of the present embodiment, when the battery stack is not in use, the cooling air flows through the inter-cell flow paths 5 in the opposite direction to when the battery stack is in use, and the reverse flow of cooling air washes away and removes dust and foreign matter that has accumulated near the inlets of the inter-cell flow paths while the battery stack is in use. This makes it possible to avoid a reduction in the cooling effect due to the accumulation or accumulation of dust and foreign matter near the inlets of the inter-cell flow paths, and is expected to prevent performance degradation of the battery cells.

[0020] The above description has been given in relation to the embodiment of the present invention, but it will be apparent to those skilled in the art that many modifications and changes can be easily made thereto, and that the present invention is not limited to the embodiment exemplified above, but can be applied to various devices without departing from the concept of the present invention.

Claims

[Claim 1] A cooling device for a battery stack formed by stacking a plurality of battery cells, an inlet for allowing cooling air to flow into the battery stack; an inter-cell flow passage through which the cooling air flows, the inter-cell flow passage being formed so as to branch from the inlet and extend between each of the battery cells; an outlet through which the cooling air from the inter-cell flow passages is joined and discharged; and a bypass flow path that is connected from the inlet to the outlet by bypassing the inter-cell flow path; an exhaust port that exhausts the cooling air to the outside between the inlet and the inlet of the inter-cell flow path; an inlet side switching valve that selectively closes one of a connection flow path before branching from the inlet to the inter-cell flow path and the outlet; an outlet side switching valve that selectively closes one of an outlet end of the bypass flow path connected to the outlet and the outlet; a switching valve control means for controlling the states of the inlet side switching valve and the outlet side switching valve; having the switching valve control means, during use of the battery stack, causes the inlet side switching valve to close the exhaust outlet and the outlet side switching valve to close the outlet end of the bypass flow path, so that the cooling air flows directly from the inlet to each of the inter-cell flow paths and flows out from the outlets, and, when use of the battery stack is stopped, causes the inlet side switching valve to close the connecting flow path and the outlet side switching valve to close the outlet, so that the cooling air passes from the inlet to the bypass flow path, and then flows through each of the inter-cell flow paths from the outlet side to the inlet side, and flows out from the exhaust outlet.

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