JP6516577B2 - Battery pack cooling system - Google Patents

Description

  The present invention relates to a battery pack cooling device, and more particularly to a battery pack cooling device mounted on a vehicle.

  BACKGROUND In recent years, a hybrid vehicle (HEV) that can effectively improve a fuel consumption rate (fuel consumption) of a vehicle by using an engine and an electric motor in combination has been widely put to practical use. In addition, electric vehicles (EVs) that use only an electric motor as a power source and do not discharge exhaust gas have also been put to practical use.

  Such hybrid vehicles and electric vehicles are equipped with a high voltage battery for supplying power to the electric motor (or storing the regenerated power). Here, since the battery generally has a reduced life (and the durability is also deteriorated) when the temperature becomes high, it is necessary to suppress the charge / discharge output in order to suppress the heat generation of the battery. Therefore, conventionally, for example, a battery cooling device is used that sends air to a battery pack to cool the battery, thereby suppressing a temperature rise due to heat generation of the battery and preventing a decrease in performance or life. (See, for example, Patent Document 1).

  Here, in Patent Document 1, a battery of a vehicle drive source is disposed as a battery assembly including a plurality of units, and these are sucked by an air exhaust fan disposed in an exhaust duct connected to the exhaust side to cool them. A cooling structure of a battery pack is disclosed. In this battery assembly cooling structure, an exhaust collecting chamber is formed immediately after each exhaust port of each battery pack in the exhaust duct, and one exhaust fan is installed downstream of the exhaust collecting chamber. Therefore, according to the cooling structure of the battery assembly, the air flow can be evenly drawn from a plurality of battery assemblies even with only one fan by the intake operation of the fan and the mixing operation of the exhaust air after cooling by the exhaust collecting chamber. Each battery pack can be effectively cooled.

Unexamined-Japanese-Patent No. 2001-102099

  However, for example, when the layout of the duct is limited due to the mounting requirements of the vehicle and the shape of the duct becomes complicated, the flow rate of the cooling air flowing to the plurality of battery cells may vary, that is, There may be places where it is difficult for the cooling air to flow. In such a case, the temperature of the battery cell may vary, that is, among the plurality of battery cells, a battery cell having a relatively high temperature may be generated. As a result, as described above, the charge / discharge performance of the battery cell having a high temperature may be deteriorated, and the life may be shortened (the durability is also deteriorated).

  The present invention has been made to solve the above problems, and a battery pack cooling device capable of reducing temperature variations of battery cells in a plurality of stacks (battery modules) constituting the battery pack. Intended to be provided.

  The battery pack cooling device according to the present invention is a battery pack cooling device configured by including a plurality of stacks including a plurality of battery cells, and includes a cooling fan for sending a cooling air, and a cooling air sent from the cooling fan. Among the air intake ducts for delivering each of the plurality of stacks, and the battery cells contained in the plurality of stacks constituting the battery pack, the cooling air discharged through the stack where there is no battery cell having a relatively high temperature And an exhaust duct for discharging the exhaust gas of the stack in which a battery cell having a relatively high temperature is present in the vicinity of the exhaust point of the battery cell.

  According to the battery pack cooling device according to the present invention, among the battery cells included in the plurality of stacks (battery modules) constituting the battery pack, the battery cells having a relatively high temperature do not pass through and are discharged The exhaust gas is discharged to the vicinity of the exhaust point (exhaust outlet) of the battery cell in the stack where the battery cell having a relatively high temperature is present. Therefore, the exhaust outlet vicinity of the said battery cell becomes negative pressure, the volume (flow volume) of the cooling air which flows through a battery cell increases, and cooling of a battery cell is accelerated | stimulated. As a result, it is possible to reduce temperature variations (that is, to cool uniformly) of battery cells in a plurality of stacks constituting the battery pack. Further, in this case, even if the position of the battery cell having a relatively high temperature is changed, the position of the exhaust port (discharge port) of the exhaust duct is changed without changing the shape or layout of the cooling fan or the intake duct. Since it can respond only by changing, it is excellent in cost and layout.

  In the battery pack cooling device according to the present invention, the exhaust duct collects the exhaust gas discharged through the stack where there is no battery cell having a relatively high temperature, and there is a battery cell having a relatively high temperature. It is preferable to discharge it centrally to the exhaust point of the battery cell in the stack.

  In this case, the exhaust point of the battery cells in the stack where the relatively high temperature battery cells are present is collected (exhaust points of the battery cells (exhaust points (exhausts)). Exit) It is expelled concentratedly in the vicinity. Therefore, the air volume (flow rate) discharged to the vicinity of the exhaust point of the battery cell having a relatively high temperature can be increased, and the negative pressure near the exhaust point can be further strengthened. Thus, the volume of the cooling air flowing through the battery cell can be increased, and the cooling of the battery cell can be further promoted.

  In the battery pack cooling apparatus according to the present invention, a plurality of stacks are arranged in upper and lower two stages, and an exhaust duct constitutes a stack arranged in the lower stage, the exhaust discharged through the stack arranged in the upper stage Among the battery cells, it is preferable to discharge the battery cell near the exhaust point of the battery cell whose temperature is relatively high.

  In this case, a plurality of stacks are arranged in upper and lower two stages, and the exhaust gas passing through the stack arranged in the upper stage is relatively high in temperature among battery cells constituting the stack arranged in the lower stage. It is discharged near the exhaust point of the battery cell. Therefore, even when a battery cell having a relatively high temperature is present in the stack disposed in the lower stage, negative pressure can be applied near the exhaust point of the battery cell, and the cooling air flowing through the battery cell Air volume can be increased to promote cooling of the battery cell.

  In the battery pack cooling device according to the present invention, the exhaust port of the exhaust duct is preferably provided at substantially the same height as the upper surface of the battery cell constituting the stack disposed in the lower stage.

  In this case, the exhaust port of the exhaust duct is provided at substantially the same height as the upper surface of the battery cell constituting the stack disposed in the lower stage. Therefore, it is possible to discharge the exhaust gas in the vicinity of the exhaust point of the battery cell having a relatively high temperature while preventing the exhaust gas discharged from the exhaust duct from being diffused. Therefore, negative pressure can be applied to the vicinity of the exhaust point of the battery cell having a relatively high temperature more effectively, and the volume of the cooling air flowing through the battery cell can be increased. As a result, it is possible to further accelerate the cooling of the battery cell.

  According to the present invention, in a battery pack cooling apparatus configured to have a plurality of stacks (battery modules) including a plurality of battery cells, temperature variations of battery cells in the plurality of stacks constituting the battery pack are reduced. It becomes possible.

It is a figure which shows the structure (planar arrangement | positioning of the stack | stuck of an upper stage and the stack | stuck of a lower stage) of the cooling device of the battery pack which concerns on embodiment. It is a sectional view showing arrangement of a stack (battery module) when a battery pack concerning an embodiment is seen from the side direction of vehicles. It is a perspective view which shows the shape of an exhaust duct. It is a figure which shows the flow of the cooling air which flows through the 3rd stack when there is an exhaust duct, and the flow of the cooling air when there is no exhaust duct (comparative example). It is a figure which shows air volume distribution of the cooling air for every battery cell which comprises the 3rd stack in the case where there is an exhaust duct and there is no exhaust duct (comparative example). It is a figure which shows the temperature distribution for every battery cell which comprises a 3rd stack in the case where there is an exhaust duct and there is no exhaust duct (comparative example), respectively.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals are used for the same or corresponding parts. Further, in the respective drawings, the same elements are denoted by the same reference numerals, and duplicate explanations will be omitted.

  First, the configuration of the battery pack cooling device according to the embodiment will be described with reference to FIGS. 1 to 3. Here, FIG. 1 is a diagram showing a configuration of the cooling device of the battery pack 1 (planar arrangement of the stacks 104 and 105 in the upper stage and the stacks 101 to 103 in the lower stage). FIG. 2 is a cross-sectional view showing the arrangement of stacks (battery modules) 101 to 105 when battery pack 1 is viewed from the side direction (vehicle width direction) of the vehicle. FIG. 3 is a perspective view showing the shape of the exhaust duct 40 (a perspective view as viewed from the rear side of the vehicle).

  The battery pack 1 is mounted on, for example, a hybrid vehicle (HEV) or an electric vehicle (EV), and supplies power to the electric motor (or stores the regenerated power). The battery pack 1 is mounted, for example, under a luggage compartment provided behind a rear seat or under the floor of a vehicle. The battery pack 1 is configured to include a plurality of (generally five in the present embodiment) stacks (battery modules) 101 to 105 having a substantially prismatic shape.

  In each of the five stacks 101 to 105, the stacking direction (the details will be described later) of the plurality of battery cells 111 (1) to 115 (n) constituting each of the stacks 101 to 105 matches the vehicle width direction. Are arranged parallel to one another. In addition, the five stacks 101 to 105 are divided into upper and lower two stages. More specifically, in the lower part, the third stack 103, the second stack 102, and the first stack 101 are arranged in parallel from the vehicle front side to the vehicle rear side. At the upper stage, the fifth stack 105 and the fourth stack 104 are arranged in parallel from the vehicle front side to the vehicle rear side.

  Each of the stacks (battery modules) 101 to 105 is configured by alternately stacking a plurality of battery cells 111 (1) to 115 (n) and a separator.

  Each of the battery cells 111 (1) to 115 (n) is, for example, a substantially rectangular prismatic battery covered with a prismatic outer can. Here, lithium ion batteries are suitably used as the battery cells 111 (1) to 115 (n). However, instead of the lithium ion battery, for example, a chargeable / dischargeable secondary battery such as a nickel hydrogen battery can be used.

  Here, in the present embodiment, the cooling air is flowed into the battery pack 1 in which the first to fifth stacks 101 to 105 are stored by the two cooling fans (the first cooling fan 21 and the second cooling fan 22). Thus, the air-cooling type cooling method of cooling the first to fifth stacks 101 to 105 (battery cells 111 (1) to 115 (n)) is adopted.

  FIG. 1 shows the flow of cooling air for cooling the first to fifth stacks 101 to 105 (battery cells 111 (1) to 115 (n)). The inlets of the first cooling fan 21 and the second cooling fan 22 are installed, for example, on the left and right (both sides) of the rear seat. Air (cooling air) taken in from the vehicle interior by the first cooling fan 21 and the second cooling fan 22 is sent to the stacks 101 to 105 through the two intake ducts (the first intake duct 31 and the second intake duct 32). The battery cells 111 (1) to 115 (n) are cooled by flowing through the slits between the battery cells constituting each of the stacks 101 to 105.

  More specifically, as shown in FIG. 1, the first intake fan 31 is connected to the first cooling fan 21. The first intake duct 31 is branched into three intake ducts 311, 312, and 312, and sends cooling air to each of the first stack 101, the second stack 102, and the third stack 103 disposed at the lower stage. On the other hand, the second cooling duct 22 is connected to the second cooling fan 22. The second air intake duct 32 branches into two air intake ducts 321 and 322, and sends cooling air to the fourth stack 104 and the fifth stack 105 disposed in the upper stage, respectively.

  The cooling air sent to the stacks 101 to 105 flows through the slits between the battery cells constituting the stacks 101 to 105 as described above, and is discharged rearward (toward the vehicle). At that time, the exhaust gas that has passed through each of the first to fourth stacks 101 to 104 is discharged rearward as it is. On the other hand, the exhaust gas having passed through the fifth stack 105 is collected by the exhaust duct 40 attached to the rear of the fifth stack 105, and the battery cells 113 (n-2) to 113 (n) located at the right end of the third stack 103. It is discharged near the exhaust point of).

  Here, the exhaust duct 40 is a stack in which battery cells having a relatively high temperature do not exist among the battery cells 111 (1) to 115 (n) included in the five stacks 101 to 105 constituting the battery pack 1 The exhaust gas passing through is collected to be concentrated and discharged near the exhaust point of the battery cell in the stack where the battery cell having a relatively high temperature is present.

  In the example of the present embodiment, as shown in FIGS. 1 and 3, the exhaust duct 40 is attached to the exhaust side of the fifth stack 105 disposed in the upper stage, and is discharged through the fifth stack 105. The exhaust gas is discharged to the vicinity of the exhaust point of the battery cells 113 (n-2) to 113 (n) at the right end of the third stack 103 disposed in the lower stage.

  Here, as shown in FIG. 2, the exhaust port of the exhaust duct 40 is provided at substantially the same height as the upper surface of the lower third stack 103 (battery cells 113 (1) to 113 (n)). . That is, the open end face of the exhaust port of the exhaust duct 40 and the upper surface of the third stack 103 (battery cells 113 (1) to 113 (n)) are arranged in parallel and substantially in the same plane. The exhaust port of the exhaust duct 40 is preferably formed in a tapered shape so that the flow passage area is smaller as it is closer to the tip.

  With the configuration as described above, the battery having a relatively high temperature among the battery cells 111 (1) to 115 (n) included in the plurality of stacks (battery modules) 101 to 105 configuring the battery pack 1 A battery cell (in the present embodiment, battery cells 113 (n−2) to It is discharged near the exhaust point of the said battery cell 113 (n-2)-113 (n) of the stack | stuck (this embodiment 3rd stack 103) which 113 (n) exists. Therefore, the exhaust outlets of the battery cells 113 (n-2) to 113 (n) become negative pressure, and the volume (flow rate) of the cooling air flowing through the battery cells 113 (n-2) to 113 (n) increases. Thus, cooling of the battery cells 113 (n-2) to 113 (n) is promoted.

  Here, the flow of the cooling air flowing through the third stack 103 (in the present embodiment) when there is the exhaust duct 40 in FIG. 4 (the lower part of FIG. 4), and the third when the exhaust duct 40 is not The flow of the cooling air which flows through the stack 103 (upper part in FIG. 4) is shown. In the case where there is no exhaust duct 40 (comparative example), as shown in the upper part of FIG. 4, in the third stack 103, cooling is performed to the three battery cells 113 (n-2) to 113 (n) It was difficult for the wind to flow, and the temperatures of these battery cells 113 (n-2) to 113 (n) were higher than the temperatures of the other battery cells 113 (1) to 113 (n-3).

  On the other hand, when the exhaust duct 40 is provided (this embodiment), as shown in the lower part of FIG. 4, the battery cells 113 (n−2) to 113 (n) constituting the third stack 103 The exhaust air from the fifth stack 105 is collected and discharged near the exhaust point (see the area of the ellipse in FIG. 4), whereby the battery cells 113 (n-2) to 113 (n) forming the third stack are discharged. Negative pressure is generated near the exhaust point of the air, which makes it easy for the cooling air to flow.

  Therefore, in order to confirm the suppression effect on the variation of the cooling air volume and the temperature variation by the exhaust duct 40, the difference of the variation of the cooling air volume due to the presence or absence of the exhaust duct 40 and the difference of the temperature variation were confirmed. The results are shown in FIG. 5 and FIG. Here, FIG. 5 shows battery cells 113 (1) to 113 (n) that constitute the third stack 103 when there is the exhaust duct 40 (this embodiment) and when there is no exhaust duct 40 (comparative example). It is a figure which shows air volume distribution of the cooling air for every. Further, FIG. 6 shows each of the battery cells 113 (1) to 113 (n) constituting the third stack 103 when there is the exhaust duct 40 (this embodiment) and when there is no exhaust duct 40 (comparative example). It is a figure which shows the temperature distribution of.

  As shown in FIG. 5, when the exhaust duct 40 is not provided, the cooling air volumes of the battery cells 113 (n-2) to 113 (n) constituting the third stack 103 are different from those of the other battery cells 113 (1) to 113 ( Although the amount of cooling air is smaller than n-3), the amount of cooling air of these battery cells 113 (n-2) to 113 (n) can be reduced to the other battery cells 113 (1) to 113 (n) by attaching the exhaust duct 40. It becomes substantially the same as the cooling air volume of (n-3), and the air volume distribution is improved. That is, the cooling air flows uniformly to the battery cells 113 (1) to 113 (n).

  Therefore, as shown in FIG. 6, when there is no exhaust duct 40, the temperature of the battery cells 113 (n-2) to 113 (n) constituting the third stack 103 is different from that of the other battery cells 113 (1) to 113 (1). Although the temperature is higher than the temperature of (n−3), by attaching the exhaust duct 40, the temperatures of these battery cells 113 (n−2) to 113 (n) become other battery cells 113 (1) to 113 (n). This becomes substantially the same as n-3), and the temperature variation for each of the battery cells 113 (1) to 113 (n) is improved. That is, the temperatures of the battery cells 113 (1) to 113 (n) become uniform, and the maximum temperature is lowered.

  As described above, according to the present embodiment, among the battery cells 111 (1) to 115 (n) included in the plurality of stacks 101 to 105 configuring the battery pack 1, the battery having a relatively high temperature Exhaust gas that has passed through the stack (in the present embodiment, the fifth stack 105) in which no cells are present has battery cells (in the present embodiment, battery cells 113 (n-2) to 113 (n)) having a relatively high temperature. It is discharged to the vicinity of the exhaust point of the battery cells 113 (n-2) to 113 (n) of the stack (in the present embodiment, the third stack 103). Therefore, the exhaust outlets of the battery cells 113 (n-2) to 113 (n) become negative pressure, and the volume (flow rate) of the cooling air flowing through the battery cells 113 (n-2) to 113 (n) increases. The cooling of the battery cells 113 (n-2) to 113 (n) is promoted. As a result, temperature variations of the battery cells 113 (1) to 113 (n) in the third stack (battery module) 103 can be reduced (that is, uniformly cooled). Further, in this case, even if the position of the battery cell having a relatively high temperature is changed, the exhaust port of the exhaust duct 40 (without changing the shapes and layouts of the cooling fans 21 and 22 and the intake ducts 31 and 32) Since it can respond only by changing the position of the discharge port, it is excellent in cost and layout.

  In particular, according to the present embodiment, all the exhaust gas having passed through the fifth stack 105 in which there is no battery cell having a relatively high temperature is collected, and the battery cells 113 (n−2) to 113 having a relatively high temperature are collected. It is concentrated and discharged near the exhaust point (exhaust outlet) of the battery cells 113 (n-2) to 113 (n) of the third stack 103 in which (n) exists. Therefore, the air volume (flow rate) discharged to the vicinity of the exhaust point of the battery cells 113 (n-2) to 113 (n) having a relatively high temperature can be increased, and the negative pressure near the exhaust point can be further strengthened. it can. Therefore, the volume (flow rate) of the cooling air flowing through the battery cells 113 (n-2) to 113 (n) can be increased, and the cooling of the battery cells 113 (n-2) to 113 (n) can be further promoted. Is possible.

  According to the present embodiment, the five stacks 101 to 105 are arranged in upper and lower two stages, and the exhaust passing through the fifth stack 105 arranged in the upper stage constitutes the third stack 103 arranged in the lower stage. Of the battery cells 113 (1) to 113 (n), the battery cells 113 (n-2) to 113 (n) having a relatively high temperature are discharged near the exhaust points. Therefore, negative pressure can be applied near the exhaust points of the battery cells 113 (n-2) to 113 (n) disposed at the lower end, and the battery cells 113 (n-2) to 113 (n) can be It is possible to promote the cooling of the battery cells 113 (n-2) to 113 (n) by increasing the flow rate of the cooling air flowing.

  According to the present embodiment, the exhaust port of the exhaust duct 40 is provided at substantially the same height as the upper surface of the lower third stack 103 (battery cells 113 (1) to 113 (n)). Therefore, while preventing the exhaust gas discharged from the exhaust duct 40 from being diffused, it can be discharged to the vicinity of the exhaust point of the battery cell battery cells 113 (1) to 113 (n) having a relatively high temperature. Therefore, negative pressure can be applied more effectively near the exhaust points of battery cells 113 (n-2) to 113 (n) having a relatively high temperature, and battery cells 113 (n-2) to 113 (n n) It is possible to increase the volume of cooling air flowing. As a result, cooling of the battery cells 113 (n-2) to 113 (n) can be further promoted.

  Further, according to the present embodiment, the exhaust port of the exhaust duct 40 is formed in a tapered shape so that the flow passage area becomes smaller as it is closer to the tip, so the flow velocity of the exhaust discharged from the exhaust duct 40 It can be early. Therefore, the negative pressure in the vicinity of the exhaust point of the battery cell (the battery cell 113 (n-2) to 113 (n) in the third stack 103 in the present embodiment) having a relatively high temperature can be increased. The amount of cooling air flowing through the battery cells can be increased. As a result, it is possible to further accelerate the cooling of the battery cell.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above embodiment, the exhaust duct 40 is provided, and the exhaust of the fifth stack 105 is discharged to the exhaust point of the third stack 103 (the exhaust point of the battery cells 113 (n-2) to 113 (n)). Although the exhaust duct is not limited to this example, the exhaust duct can be optionally provided so as to eliminate the variation (i.e., the variation in temperature) of the cooling air between the battery cells. For example, the exhaust of the fifth stack 105 may be discharged to the exhaust point of the first stack 101 or the second stack 102, or the exhaust of the fourth stack 104 may be discharged to the exhaust points of the first to third stacks 101 to 103. It is good also as composition. Further, the exhaust of the stacks 101, 102, and 103 disposed in the lower stage may be discharged to the exhaust point of the stacks 104, 105 disposed in the upper stage.

  Although the battery pack 1 includes the five stacks (battery modules) 101 to 105 in the above embodiment, the number of stacks (battery modules) is not limited to five. Further, the stacks 101 to 105 may not be divided into two upper and lower stages. Furthermore, the number of exhaust ducts 40 may not be one.

  Although the two cooling fans 21 and 22 are provided in the above embodiment, the number of the cooling fans 21 and 22 may not be two.

  In the installation of the exhaust duct 40, not only the temperature at the time of traveling of the battery cells 111 (1) to 115 (n) but also, for example, the temperature at the time of stopping is taken into consideration. ) And you may decide the place where you discharge the exhaust.

1 Battery pack 101, 102, 103, 104, 105 stack (battery module)
111 (1) to 115 (n) battery cells 21, 22 cooling fans 31, 32, 311, 312, 313, 321, 322 intake ducts 40 exhaust ducts

Claims (4)

A cooling device for a battery pack comprising a plurality of stacks including a plurality of battery cells, the cooling device comprising:
With a cooling fan that sends cooling air,
An intake duct for delivering cooling air sent from the cooling fan to each of the plurality of stacks;
And an exhaust duct that discharges the exhaust of the cooling air discharged through the stack. The exhaust duct does not have the exhaust duct among the battery cells included in the plurality of stacks that configure the battery pack. There is a battery cell with a relatively high temperature when it is assumed that the exhaust duct does not have the exhaust duct and the exhaust of the cooling air discharged through the stack where there is no battery cell with a relatively high temperature under the assumption. A cooling system for a battery pack characterized in that the stack is discharged near the exhaust point of the battery cell.   The exhaust duct collects the exhaust discharged through the stack where the relatively high temperature battery cells are not present, and exhausts the battery cells of the stack where the relatively high temperature battery cells are present. The battery pack cooling device according to claim 1, wherein the battery pack is discharged centrally. The plurality of stacks are arranged in two upper and lower stages,
The exhaust duct discharges the exhaust discharged through the stack disposed in the upper stage to the exhaust point of the battery cell having a relatively high temperature among the battery cells constituting the stack disposed in the lower stage. The battery pack cooling device according to claim 1 or 2, characterized in that   4. The battery pack cooling device according to claim 3, wherein an exhaust port of the exhaust duct is provided at substantially the same height as an upper surface of a battery cell constituting a stack disposed in the lower stage.

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