JP5302760B2 - Battery cooling structure - Google Patents

Description

The present invention relates to a cooling structure for a battery (particularly an assembled battery). In particular, the present invention relates to an air-cooled battery cooling structure for cooling a battery with cooling air.

In an electric vehicle, a hybrid vehicle, and the like, an assembled battery in which secondary batteries are assembled as a power source is used. In the process of charging or discharging, if the battery overheats or the temperature difference between the batteries increases, the performance of the battery may deteriorate or the battery may be damaged. Usually, these assembled batteries are stored in the battery case. Then, cooling air is sent into the battery case to cool the assembled battery.

In cooling, it is necessary to equalize the temperature of a plurality of batteries constituting the assembled battery as much as possible and cool the batteries efficiently. For this reason, various battery cooling structures have been proposed.
For example, Patent Document 1 discloses a cooling structure in which a plurality of air guide plates are provided on the cooling air inlet side of the battery case so that the cooling air passing between the air guide plates is directed between the battery modules. Has been. Patent Document 2 discloses a battery cooling structure in which a cooling air flow changing member that changes the flow of cooling air in a direction away from the assembled battery is provided at a cooling air introduction port that supplies cooling air to the battery case. Yes.

JP 2004-71349 A JP 2007-250515 A

However, these conventional battery cooling structures attempt to optimize the air flow around the assembled battery so that the battery is uniformly cooled. However, the cooling air flow realized is a steady flow. It is. Therefore, once the structure of the battery cooling structure is determined, the steady flow field is determined accordingly, so even if there is a place where the flow is stagnant or where the flow is strong, there is no design change. As a result, the flow field cannot be changed or improved any further, and as a result, the battery becomes hot in a place where the flow is stagnant, and the battery becomes cold in a place where the flow is strong. There was a limit.

Accordingly, an object of the present invention is to provide a battery cooling structure capable of cooling so that the temperatures of the batteries constituting the assembled battery become more uniform.

As a result of intensive studies, the inventors of the present invention have provided a flow control plate having a specific structure on the cooling air inlet side of the battery case. It was found that time-series fluctuations occurred and the temperature of the battery constituting the assembled battery could be made more uniform, and the present invention was completed.

The present invention stores an assembled battery consisting of a plurality of battery modules in a battery case, introduces cooling air into the battery case from a cooling air inlet provided in the battery case, cools the battery module with cooling air, A battery cooling structure for discharging cooling air to the outside of the battery case from a cooling air outlet port provided in the battery case, and in the region upstream of the assembled battery inside the battery case, the inside of the battery case is located downstream and upstream The flow control plate is provided with a plurality of slits substantially in parallel so that the cooling air flow downstream of the flow control plate is an unsteady flow. The battery cooling structure is characterized in that the distance between the flow control plate and the most upstream battery module is L, the slit pitch is W, and W <L <6W .

In the present invention, the battery module is cylindrical, and it is preferable that the distance between the flow control plate and the most upstream battery module is L, and the diameter of the battery module is DB, and 0.5DB <L <3DB. (Claim 2). Further, a battery module is rod-like or plate-like or block-like, it is preferable that the slit is provided so that the longitudinal direction substantially parallel to the battery module (claim 3).

According to the present invention, the flow of the cooling air in the battery case becomes a flow that flows in a non-stationary meandering and deflecting manner in the downstream region of the flow control plate provided with the slit. The stagnation region and the region where the cooling air is too strong are suppressed from appearing constantly, and the effect that the temperature of the battery constituting the assembled battery can be made more effective can be obtained. In particular , the distance between the flow control plate and the most upstream battery module is L, the diameter of the cylindrical battery module is DB, and 0.5DB <L <3DB, or the longitudinal direction of the battery module and the slit direction are approximately If they are parallel, the battery temperature can be made more uniform.

It is sectional drawing which shows the battery cooling structure of embodiment of this invention. It is a figure which shows the slit shape of the flow control board in this invention. It is a figure which shows the simulation result of the cooling air flow in embodiment of this invention. It is a figure which shows the simulation result of the cooling wind flow in another time in embodiment of this invention. It is a figure which shows the simulation result of the cooling wind flow in another time in embodiment of this invention. It is a figure which shows the simulation result of the cooling wind flow in another time in embodiment of this invention. It is a figure which shows the simulation result of the cooling air flow in the prior art example without a flow control board. It is sectional drawing which shows the main dimensions in the battery cooling structure of embodiment of this invention. It is a figure which shows the slit shape of another embodiment of the flow control board in this invention. It is sectional drawing which shows the shape of another embodiment of the flow control board in this invention. It is sectional drawing which shows the shape of another embodiment of the flow control board in this invention.

An embodiment of a battery cooling structure of the present invention will be described with reference to the drawings, taking as an example a battery case that houses an assembled battery for a hybrid vehicle. FIG. 1 is a cross-sectional view of the embodiment of the battery cooling structure of the present invention along the flow direction of cooling air. In FIG. 1, only the inner peripheral surface of the battery case is shown.

In the internal space of the box-shaped battery case 1, rod-shaped battery modules 2 and 2 are arranged in parallel at a predetermined interval. The battery modules 2 and 2 are electrically connected in series or in parallel to form an assembled battery. In the present embodiment, the battery constituting the battery module is a nickel metal hydride battery, and the battery module 2 in which the batteries are connected in series has a cylindrical bar shape.

In FIG. 1, battery modules 2 and 2 are arranged in the depth direction of the drawing, and 14 battery modules are arranged in a 2 × 7 array. Each of the battery modules 2 and 2 has a predetermined interval (gap) between the inner surface of the battery case 1 and the adjacent battery module, and is accommodated inside the box-shaped battery case so that cooling air flows through the gap. Is supported.

The battery case 1 is a hollow box-shaped member formed of metal or synthetic resin. The battery case 1 is provided with a cooling air inlet 11 and a cooling air outlet 12 to cool the internal space of the battery case 1. Constructs a wind passage. The battery case 1 is used for cooling the assembled battery by connecting the cooling air inlet 11 and the cooling air outlet 12 with peripheral members such as a duct and a blower fan to form a series of cooling air passages.

In the present embodiment, a blower fan (not shown) is provided downstream of the cooling air outlet 12 and is connected to the upstream side of the cooling air inlet 11 on the left side of the drawing (not shown). Then, the cooling air flows into the battery case 1, cools the battery while passing through the gap between the battery modules 2 and 2, and the cooling air flows out from the cooling air outlet to the right side of the figure.

In the present invention, the flow control plate 13 is provided inside the battery case 1 so as to partition the internal space of the battery case between the cooling air inlet side and the cooling air outlet side, and to block the flow of the cooling air. . The flow control plate 13 is integrally attached to the battery case 1 at a position upstream of the battery modules 2 and 2 (assembled battery).

The flow control plate 13 has a plurality of (eight in this embodiment) slits (opening holes) 132 along the length direction of the battery module (in the depth direction of the drawing in FIG. 1) and substantially parallel to the battery module. It is provided to become. Between adjacent slits 132 and slits 132, block portions 131 and 131 that block the flow of cooling air are provided alternately with the slits 132 and 132. The internal space of the battery case 1 is configured such that the upstream side and the downstream side communicate with each other through the slits 132 and 132, and the assembled battery (battery modules 2 and 2) provided on the downstream side blows out from the slits. Cooled by cooling air.

FIG. 2 is a cross-sectional view of the flow control plate 13 viewed from the direction of the arrow in FIG. 1, and the slits 132 and 132 provided in the flow control plate 13 are along the length direction of the battery modules 2 and 2. The battery module 2 is provided over the entire length. When the inside of the battery case is partitioned into a plurality of cooling air passages by plate-like partition members provided along the flow direction of the cooling air, the slits 132 and 132 are respectively partitioned cooling air passages. Preferably, the battery module is provided over the entire width in the length direction of the battery module.

Main specific dimensions of the battery case 1 and the flow control plate 13 in the present embodiment are as follows. The height (vertical direction in FIG. 1) of the battery case 1 is 84 mm, and the length (horizontal direction in FIG. 1) is 330 mm. The cooling air inlet 11 has a height of 82 mm, which is substantially equal to the height of the battery case 1, and the cooling air outlet 12 has a height of 42 mm, a height that slightly restricts the flow from the height of the battery case 1. Has been. The diameter of the battery module 2 is 28 mm.

The flow control plate has a thickness of 2 mm, the width of the slit 132 (vertical direction in FIG. 1) is 3 mm, the width of the block 131 (vertical direction in FIG. 1) is 7 mm, and therefore the slit interval (pitch) is 10 mm. It has become. The flow control plate 13 is provided at a position spaced downstream from the portion where the cooling air introduction port 11 opens toward the battery case internal space, and the upstream side from the battery modules 2 and 2 located at the uppermost stream. At a position 50 mm away.

The battery case having the battery cooling structure can be manufactured by a known manufacturing method. For example, the battery case 1 is formed by injecting a synthetic resin (for example, polypropylene resin) into a case member divided into an open box and a lid. It can be formed by molding. The flow control plate 13 can also be formed by injection molding of synthetic resin (for example, polypropylene resin), and may be integrally formed with the case member of the battery case 1 if possible. Of course, the flow control plate 13 may be formed separately from the case using a metal plate or the like, and attached to a predetermined position when the battery case is assembled.

A battery case in which the battery modules are arranged at predetermined positions in the battery case 1, wiring between the battery modules is established, the lid of the battery case is closed with the flow control plate incorporated, and the assembled battery of the above embodiment is stored And the battery cooling structure is completed.

The operation and effect of the battery cooling structure of the present invention will be described.
In the battery cooling structure of the present invention, since the flow control plate 13 is provided with a plurality of slits 132 and 132 in a substantially parallel manner, the flow downstream of the flow control plate 13 is changed in an unsteady manner. It becomes a place.

In the space on the downstream side of the flow control plate 13, the cooling air is blown out at the slit portion 132, while the flow of the cooling air is blocked at the block portion 131 between the slits, and therefore the boundary between the slit 132 and the block portion 131. In each part, vortex lines are formed along the periphery of the slit 132. These vortex lines grow with the flow of cooling air or flow downstream to disappear.

In the present invention, since a plurality of slits 132 and 132 are provided side by side, these vortex lines generated at the peripheral edge of each slit 132 interfere with each other, and cooling air blown out from each slit 132 and 132 is generated. Move closer to or away from each other. As a result, in the space between the flow control plate 13 and the battery modules 2 and 2, the cooling air blown out from the slits interferes with each other and flows together or flows separately (in FIG. 1). It becomes an unsteady flow field that changes irregularly when it is deflected upward or downward.

The result of visualizing such an unsteady flow field by numerical fluid simulation is shown in FIGS. The flow simulation was performed in a shape corresponding to the above-described embodiment, and the simulation result obtained an unsteady flow solution in which the flow field changes with time. FIGS. 3 to 6 show the flow lines of the flow passing through each slit at a specific time, together with the outer shape of the battery module, and the flow passing through the slits meanders and separates, It shows how it flows between them.

As shown in the simulation results, the cooling air blown out from the eight slits meanders and deflects randomly in the vertical direction, and in some cases, as shown in FIG. The cooling air that flows between the battery module and the battery case, exits from the three slits in the center, flows between the upper and lower battery modules, and the cooling air that exits from the lower three slits As shown in FIG. 4, the cooling air from the upper three slits flows between the upper battery module and the battery case, and there are three central parts. The cooling air from the upper slit flows between the upper and lower battery modules, and the cooling air from the lower two slits flows between the lower battery module and the battery case. To flow in.

At another time, as shown in FIG. 5, the cooling air from the two upper slits flows between the upper battery module and the battery case, and the cooling air from the four central slits is on the upper side. Between the lower battery module and the lower battery module, and the cooling air from the two lower slits flows between the lower battery module and the battery case. As shown, the cooling air from the upper three slits flows between the upper battery module and the battery case, and the cooling air from the two central slits flows between the upper and lower battery modules. The cooling air coming out of the lower three slits flows between the lower battery module and the battery case.

Table 1 shows how the flow field changed over time. In the table, “upper”, “middle”, and “lower” respectively indicate the number of flows from the slit that flows between the upper battery module and the battery case, and from the slit that flows between the upper and lower battery modules. Shows the number of flows and the number of flows from the slit that flows between the lower battery module and the battery case. The vertical column in the table corresponds to the execution cycle of the numerical simulation, and corresponds to the progress of time. Yes. Here, 50 cycles correspond to 0.05 seconds in real time, FIG. 3 corresponds to the 100th cycle, FIG. 4 corresponds to the 450th cycle, FIG. 5 corresponds to the 1000th cycle, and FIG. 6 corresponds to the 1600th cycle. .

As shown in Table 1, the flow passing through each slit flows to the upper side or the lower side of the battery module, and the number of flows from the slits flowing around the battery module increases or decreases. As the local flow of the battery becomes faster or slower, the flow around the battery module changes unsteadily. In addition, when taking a time average of these unsteady flows, the number of flows from the slit flowing between the upper battery module and the battery case is 2.4, and flows between the upper and lower battery modules. The number of flows from the slit is 3.4, and the number of flows from the slit that flows between the lower battery module and the battery case is 2.2. This is how the air volume is distributed.

On the other hand, when the numerical simulation result of the comparative example without the cooling air control plate 13 provided with the slit is shown, a steady solution as shown in FIG. 7 is obtained. The streamline in the figure is a streamline corresponding to the position where there is a slit. In the absence of slits, streamlines did not meander or deflect, and the flow field did not change over time.

Further, in the above flow simulation, a predetermined heat generation amount was set for each battery module, and a cooling temperature simulation for each battery module was performed. In the cooling temperature simulation, the temperature difference between the most upstream battery module and the most downstream battery module is evaluated, and the cooling air control is performed with the same cooling air volume and specifications (box height, battery diameter, heat generation, etc.). Comparison was made with or without the plate 13. As a result of the cooling temperature simulation, the temperature difference between the battery modules is 7.4 ° C. with the flow control plate (the embodiment of the present invention), and 7.9 ° C. without the flow control plate (comparative example). Met. In the embodiment of the present invention, the temperature difference between the battery modules is uniformed by 0.5 ° C., and it has been confirmed that providing a flow control plate with a slit is effective for homogenizing the temperature.

In this way, the flow of the cooling air that has passed through the slit becomes a non-stationary flow and flows around the battery module. Thus, like the conventional battery cooling structure in which the flow field of the cooling air is stationary, The place where the flow of the cooling air is stagnant or the place where the flow of the cooling air is too strong is not fixed, and the entire assembled battery can be cooled more uniformly.

The cooling air that has passed through the plurality of slits interferes with each other, and the flow downstream of the cooling air control plate 13 is changed unsteadyly to produce the effect of the present invention more effectively. Preferred specifications such as intervals are shown below. Here, the slit width is d, the slit pitch is W, the block width is S, the distance between the flow control plate and the most upstream battery module is L, and the battery module diameter is DB (FIG. 8). .

The slit width d and the block width S are preferably in a relationship of 0.2S <d <4S in order to make the flow unsteady, and more preferably 0.3S <d <2S. If the width S of the block portion becomes too small or too large, the cooling air that has passed through the slits is less likely to interfere, and the flow tends to become unsteady.

The distance L between the flow control plate and the most upstream battery module and the slit pitch W are preferably in a relationship of 0.5 W <L <8 W, and more preferably W <L <6 W. The pitch W of the slit is related to the scale of the flow field where the flow is unsteady. If L is too small relative to W, the flow to the battery module is reduced while the change in the flow unsteady is small. It will collide and the change of the flow field will become small. On the other hand, if L is excessive with respect to W, the unsteady flow caused by the slit will attenuate and become a steady flow before reaching the battery module, and space efficiency of the battery case The above is also not preferable.

Further, the distance L between the flow control plate and the most upstream battery module and the diameter DB of the battery module preferably have a relationship of 0.5DB <L <3DB, and 0.8DB <L <2DB. It is more preferable. If L is too small with respect to DB, even if the cooling air passing through each slit becomes unsteady, it will not pass through the upper side or the lower side of the battery module. In addition to making it difficult to achieve a uniform battery temperature effect, it is not preferable in terms of space efficiency of the battery case if L is excessively larger than DB.

The present invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the present invention will be described below. However, in the following description, portions different from the above-described embodiment will be mainly described, and descriptions of the same portions will be omitted.

First, an example of changing the flow control plate will be described. The slit provided in the flow control plate is preferably open over the entire length of the battery module. However, as shown in FIG. 9, for example, as shown in FIG. The flow control plate 14 may be provided by being divided in the vertical direction. Further, the slits provided substantially in parallel do not need to be completely parallel, and may be provided slightly obliquely in a range where unsteady flow occurs.

Various changes can be made to the cross-sectional structure along the flow direction of the flow control plate (slit). FIGS. 10 and 11 are cross-sectional views along various flow directions of the flow control plate 14. Show. In these figures, the left side of the figure is shown as the upstream side of the cooling air flow.

For example, as shown in FIG. 10 (a), ribs 143 and 143 may protrude in the downstream direction along the downstream edge of the slit 142 provided in the flow control plate 14. By adjusting the length of the rib 143 or the tip shape, the degree of unsteady flow in the downstream region of the flow control plate 14 can be changed. In particular, as shown in FIG. 11 (c), the rib 143 is inclined and provided so that the side surface facing the slit 142 is inclined so that the width of the slit increases toward the downstream side. It is more preferable that the degree of unsteady flow in the downstream region of the flow control plate 14 can be increased.

Further, as shown in FIG. 10 (b) or (c), the peripheral edge of the slit 142 of the flow control plate 14 is formed in an acute-angled shape on the upstream side or downstream side of the flow control plate. However, the degree of unsteady flow in the downstream region of the flow control plate can be changed and adjusted. In particular, as shown in FIG. 10B, when the slit peripheral edge of the flow control plate 14 on the upstream side of the cooling air flow is sharpened, the degree of unsteady flow in the downstream region of the flow control plate 14 can be increased. It is more preferable.

Moreover, as shown to Fig.11 (a), you may project the rib 143 toward the downstream direction from the approximate center part of the block part 141 between the slits of the flow control board 14. FIG. Further, as shown in FIG. 11B, a lip portion 144 extending in the direction of blocking the flow is provided from the front end portion of the rib 143 projecting toward the downstream direction at the substantially central portion of the block portion 141. It may be. Providing the lip 144 is more preferable because the degree of unsteady flow in the downstream region of the flow control plate 14 can be increased.

The slit intervals W may be provided at equal intervals (equal pitch), but may be provided at unequal pitches by changing the interval. It is preferable to provide the slits at equal intervals because the non-steady flow is more likely to occur due to the interference effect of the cooling air ejected from the series of slits when the intervals are equal.

The slit of the flow control plate is preferably provided substantially parallel to the rod-shaped battery module, but is not limited to this, and the battery module is not limited to this, as viewed along the direction of the global flow of cooling air. On the other hand, the slits may be provided obliquely or substantially vertically. When the battery module is provided substantially in parallel with the rod-shaped battery module, as described in the above embodiment, the air volume of the cooling air distributed to the upper side and the lower side of the battery module can be actively changed. Therefore, it is particularly effective for making the battery temperature uniform.

Further, in the description of the above embodiment, the form in which the assembled battery is stored in the hollow box-shaped battery case 1 has been described, but the embodiment of the battery case is limited to a hollow box-shaped one that is molded exclusively for the case. The battery case may be configured by combining a plurality of members such as a panel member and a block member. For example, an assembled battery is arranged on a floor panel of a vehicle body, a heat insulating panel or an electrode panel is provided so as to surround the assembled battery, and a battery case having a cooling air passage between the floor panel, the heat insulating panel, and the electrode panel is provided. It can also be configured. As described above, the battery case according to the present invention includes a battery case constituted by using / combining a member arranged around the assembled battery, in addition to the battery case constituted by a dedicated component member.

Examples of the battery constituting the assembled battery include a primary battery, a secondary battery (such as a lithium ion battery, a nickel hydride battery, and a nickel cadmium battery), a double electric capacitor, and the like. In the above embodiment, the battery module has been described as being rod-shaped, particularly cylindrical, but is not limited thereto, and may be prismatic or block-shaped, and arranged along the flow direction. It may be a flat plate. In order to effectively cool these various types of battery modules, it is clear from the above description that the longitudinal direction of the battery modules is preferably substantially parallel to the slits provided in the flow control plate. It is.

The purpose and application for which the assembled battery is used are not limited to those for automobiles. For example, a secondary battery is used for the purpose of leveling generated power in a wind power generator or a solar battery power generator. Can be used for a wide range of purposes.

INDUSTRIAL APPLICABILITY The present invention can be used for cooling large-capacity assembled batteries used in electric vehicles, power generators, and the like, and uniformly cools the batteries constituting the assembled batteries to effectively exhibit the battery performance. It can be used and has high industrial utility value.

DESCRIPTION OF SYMBOLS 1 Battery case 11 Cooling air inlet 12 Cooling air outlet 13 Flow control board 131 Block part 132 Slit 2 Battery module 14 Flow control board 141 Block part 142 Slit 143 Rib 144 Lip part

Claims (3)

An assembled battery consisting of a plurality of battery modules is stored in the battery case, cooling air is introduced into the battery case from the cooling air inlet provided in the battery case, the battery module is cooled by the cooling air, and is provided in the battery case. A battery cooling structure for discharging cooling air out of the battery case from the cooling air outlet,
In the region upstream of the assembled battery inside the battery case, a flow control plate is provided to partition the inside of the battery case into a downstream side and an upstream side,
A plurality of slits are provided in the flow control plate substantially in parallel so that the cooling air flow downstream of the flow control plate becomes an unsteady flow, and the flow control plate is located between the most upstream battery module. A battery cooling structure characterized in that the distance is L, the slit pitch is W, and W <L <6W . The battery module has a cylindrical shape, and the distance between the flow control plate and the uppermost battery module is L, and the diameter of the battery module is DB, and 0.5DB <L <3DB. 2. The battery cooling structure according to 1. 2. The battery cooling structure according to claim 1, wherein the battery module has a rod shape, a flat plate shape, or a block shape, and the slit is provided so as to be substantially parallel to a longitudinal direction of the battery module.

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