JP2020071952A - Battery pack - Google Patents

Abstract

To restrain increase of steam and occurrence of condensation in a pack case, in a battery pack where cooling air is circulated in the pack case.SOLUTION: A battery pack includes a battery module, a pack case receiving a battery module, a service plug for blocking an electric circuit including the battery module, an air fan circulating the cooling air in the pack case, a service plug cover attached removably to the pack case so as to cover the opening of the pack case for exposing the service plug to the outside and the service plug, a breath film provided in the service plug cover, and a gaseous flow regulation part for regulating inflow of the gas in the service plug cover into the pack case.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a battery pack including a battery module and a pack case that houses the battery module.

  BACKGROUND ART Conventionally, one including a battery module including a plurality of battery cells, an electric device connected to the battery module, and a pack case accommodating the battery module and the electric device inside is known (for example, see Patent Document 1). ). In this battery pack, a live part dense area where battery modules are arranged is formed on one side in the lateral direction inside the pack case, and a high temperature area where electric devices are arranged is formed on the other side. There is. Further, the pack case is formed with a breathing hole that communicates with a high temperature area, and the breathing hole is covered with a breathing film having a property of allowing water vapor and dry air to pass therethrough while preventing water droplets from passing therethrough. As a result, when the temperature of the air in the high temperature area rises due to the energization of the electric equipment, the temperature of the air in the high temperature area increases due to the pressure difference caused by the temperature difference between the high temperature area and the outside of the pack case. Is discharged to the outside of the pack case via the. As a result, air containing water vapor is also discharged to the outside of the pack case through the breathing membrane, so that dew condensation water can enter the battery module without using a blower that circulates cooling air inside the pack case. Can be suppressed.

JP, 2018-041614, A

  However, when the blower that circulates the cooling air inside the pack case is omitted as in the battery pack described in Patent Document 1, the output of the battery module may be limited and the battery module may be deteriorated. is there. On the other hand, in a battery pack including a blower, the cooling air can be circulated in the pack case to cool the battery module, but the temperature inside the pack case is made uniform throughout, so there is a difference in temperature inside the pack case. However, even if the structure described in Patent Document 1 which is based on the assumption that the above is formed, it is difficult to reduce the water vapor in the pack case and suppress the occurrence of dew condensation.

  Therefore, the present disclosure mainly aims to suppress an increase in water vapor and generation of dew condensation in a pack case in a battery pack in which cooling air is circulated in the pack case.

  A battery pack of the present disclosure includes a battery module, a pack case that houses the battery module, a service plug for shutting off an electric circuit including the battery module, and a blower that circulates cooling air in the pack case. A battery pack including a service plug cover detachably attached to the pack case so as to cover the opening of the pack case exposing the service plug to the outside and the service plug, and the service plug cover. It includes a breathing membrane and a gas flow restricting portion that restricts the gas in the service plug cover from flowing into the pack case.

  In the battery pack of the present disclosure, when the pressure inside the pack case is lower than the outside pressure, even if the air containing water vapor flows into the service plug cover from the outside through the breathing membrane, it flows into the service plug cover. It is possible to regulate the inflow of the air containing the vapor into the pack case by the gas flow regulating unit. Even when the humidity inside the service plug cover is lower than the outside humidity, air containing water vapor flows into the service plug cover from the outside through the breathing membrane, but the gas inside the service plug cover is inside the pack case. By restricting the inflow into the service plug cover by the gas flow restricting unit, the humidity in the service plug cover can be quickly increased, and further inflow of air containing water vapor into the service plug cover can be suppressed. As a result, in the battery pack in which the temperature difference is less likely to be formed in the pack case by circulating the cooling air in the pack case by the blower, the increase of water vapor in the pack case and the occurrence of dew condensation are favorably suppressed. Is possible. Further, in the battery pack of the present disclosure, the air circulating in the pack case can be restricted from flowing into the service plug cover by the gas flow restricting unit, so that the loss of the blower can be reduced and the efficiency can be improved. It will be possible. In addition, in the battery pack of the present disclosure, when the service plug cover is removed from the pack case for attaching / detaching the service plug, foreign matter is prevented from entering the pack case through the opening by the gas flow restricting portion. It can also be regulated.

  Further, the opening may be formed in an upper portion of the pack case, the service plug cover may be attached to the pack case so as to project upward from an upper surface of the pack case, and the breathing membrane may be provided. May be provided on the upper part of the service plug cover, and a gas passage may be formed between the ceiling surface of the pack case and the battery module to pass through the battery module and return to the blower. Good.

  Further, the gas flow restricting portion may be arranged in the pack case so as to face the peripheral edge of the opening via a gap. As a result, it is possible to allow the gas inside the service plug cover to flow into the pack case while allowing the communication between the inside and the outside of the pack case through the breathing membrane and adjusting the pressure inside the pack case. It becomes possible to regulate.

  The service plug is a housing and a grip that is detachably attached to the housing. The service plug shuts off the electric circuit when detached from the housing, and the service plug when attached to the housing. A grip for releasing the interruption of the electric circuit by the plug may be included, and the gas flow restricting portion may be integrated with the housing. This makes it possible to reduce the number of parts of the battery pack.

It is a schematic block diagram which illustrates the vehicle carrying the battery pack of this indication. It is a schematic block diagram which shows the battery pack of this indication. It is a fragmentary sectional view showing the internal structure of the battery pack of this indication. It is a sectional view showing an important section of a battery pack of this indication.

  Next, modes for carrying out the invention of the present disclosure will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a vehicle 1 equipped with a battery pack 10 of the present disclosure. In addition to the battery pack 10, the vehicle 1 shown in the figure is connected to the battery pack 10 via a power control device (not shown) including an inverter and the like, and is a motor capable of outputting driving power and regenerative braking force. An electric vehicle or a hybrid vehicle including a generator (three-phase AC motor) MG. In the present embodiment, the battery pack 10 is fixed under the floor of the vehicle 1 near the rear seat, that is, below the floor panel 2 of the vehicle body (monocoque).

  As shown in FIG. 2, the battery pack 10 includes, for example, a plurality of battery modules (battery stacks) 11 connected in series and a pack case 12 that houses the plurality of battery modules 11. Each battery module 11 includes a plurality of battery cells (not shown) connected in series or in parallel. Each battery cell is, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery. The pack case 12 also includes a lower case 13 and an upper case 14 formed of metal or resin. The lower case 13 and the upper case 14 are liquid-tightly coupled via a seal member (not shown). In the present embodiment, the plurality of battery modules 11 are arranged in the pack case 12 so as to extend in the width direction (vehicle width direction) of the pack case 12.

  Further, as shown in FIG. 3, the battery pack 10 includes two electric blowers (blowers) 15 arranged on the vehicle front side (left side in FIGS. 2 and 3) in the pack case 12, and the inside of the pack case 12. And a pair of main ducts 16 arranged in the. The pair of main ducts 16 are connected to the blower ports of the corresponding blowers 15 and extend inside the pack case 12 along the side walls of the pack case 12. A cooler (heat exchange) 17 is arranged in each main duct 16 so as to be close to the blower port of the blower 15. Each cooler 17 shares a refrigerant with, for example, an air conditioner that performs air conditioning in the vehicle interior of the vehicle 1, and can cool the air (cooling air) sent from the corresponding blower 15. The supply of the refrigerant to each blower 15 and each cooler 17 is controlled by a controller (not shown) according to the temperature of the battery module 11 and the like.

  A sub-duct 18 for supplying cooling air from the blower 15 to each battery cell of each battery module 11 is connected to each main duct 16. In the present embodiment, one of the pair of main ducts 16 (the upper main duct 16 in FIG. 3) is connected with the sub-duct 18 corresponding to the odd-numbered battery module 11 counted from the front side (the left side in the drawing). The other side (the lower main duct 16 in FIG. 3) is connected to the sub-duct 18 corresponding to the even numbered battery module 11 counted from the front side. Further, an air passage 19 for returning the cooling air passing through each battery module 11 to each blower 15 is formed between the ceiling surface of the pack case 12, that is, the ceiling case 14 and the plurality of battery modules 11. That is, the cooling air that has passed through each battery module 11 flows into the air passage 19 through the gap between the adjacent battery modules 11 and is sucked by each blower 15. As a result, by operating each blower 15, it becomes possible to circulate the cooling air inside the pack case 12.

  In addition, the battery pack 10 mainly includes an electric device (not shown) arranged on the front side in the pack case 12 and forming an electric circuit together with the plurality of battery modules 11, and a service plug 20 incorporated in the electric circuit. The electric devices arranged in the pack case 12 include a system main relay, a limiting resistor, and the like connected to the plurality of battery modules 11 via the bus bar module 110 (see FIG. 4). The service plug 20 is used for manually disconnecting an electric circuit including a plurality of battery modules 11 when inspecting and maintaining the vehicle 1.

  As shown in FIG. 4, the service plug 20 includes a service plug housing 21 made of resin and a service plug grip 22 detachably attached to the service plug housing 21. The electric circuit including the plurality of battery modules 11 is shut off when the service plug grip 22 is removed from the service plug housing 21, and when the service plug grip 22 is attached to the service plug housing 21, the electric power generated by the service plug 20 is changed. The circuit interruption is released. As shown in FIG. 4, a narrow and long central bracket 23 is fixed to the pack case 12 so as to extend in the front-rear direction of the pack case 12, and the service plug housing 21 includes a plurality of battery modules. The housing 11 is fixed to the central bracket 23 via the housing bracket 24 so as to be located above and near the central portion in the front-rear direction of 11.

  An opening 14H for exposing the service plug 20 to the outside is formed in the upper portion of the pack case 12, that is, the upper case 14, and the service plug grip 22 and a part of the service plug housing 21 have the opening 14H. Through the outside. Further, the service plug housing 21 of the service plug 20 is integrally formed with a flange-shaped (collar-shaped) gas flow restricting portion 210 so as to face the periphery of the opening 14H in the pack case 12 with a gap. There is. In the present embodiment, the outer periphery of the gas flow restricting portion 210 is located outside the peripheral portion of the opening 14H when viewed from above (upper side in FIG. 4).

  To the upper case 14 of the pack case 12, a service plug cover 25, which is made of resin or metal and has a cylindrical shape with a bottom, is detachably attached so as to cover the opening 14H and the service plug 20. The service plug cover 25 is attached to the upper case 14 so as to project upward from the upper surface of the upper case 14, and a seal member 26 is arranged between the upper case 14 and the service plug cover 25. A breathing plug 30 holding a breathing membrane 300 is attached to the service plug cover 25. The breathing plug 30 is attached to the upper part of the service plug cover 25 so that the breathing membrane 300 can come into contact with the air inside and outside the service plug cover 25. The breathing film 300 is, for example, a moisture-permeable waterproof sheet such as a non-woven fabric made of polytetrafluoroethylene, and has a property of allowing a drier and water vapor to pass therethrough while preventing water droplets from passing through. Further, the breathing film 300 allows the movement of water vapor from the direction of high humidity to the direction of low humidity when an absolute humidity difference occurs between the inside and outside of the service plug cover 25.

  As shown in FIG. 4, when the battery pack 10 is fixed below the floor panel 2 of the vehicle 1, the service plug cover 25 attached to the pack case 12 covers the opening 2H formed in the floor panel 2. It projects to the vehicle compartment side of the vehicle 1 via the. Further, on the floor panel 2, a vehicle interior cover 3 formed in a bottomed cylindrical shape with a metal or a resin so as to cover the opening 2H and the service plug cover 25 including the breathing plug 30 is attached and detached via a seal member. Can be freely attached. Accordingly, by removing the vehicle interior cover 3 and the service plug cover 25 in order, the service plug grip 22 of the battery pack 10 can be attached to and detached from the service plug housing 21. As a result, the accessibility of the service plug 20 from the vehicle interior side of the vehicle 1 can be favorably ensured.

  In the battery pack 10 configured as described above, the temperature rise of each battery module 11 is suppressed by operating each blower 15 and each cooler 17, thereby suppressing the output limitation and deterioration of each battery module 11. It becomes possible to do. Further, the outside of the service plug cover 25 and the inside of the pack case 12 include the breathing membrane 300 of the breathing plug 30, the inside of the service plug cover 25, the opening 14H of the upper case 14, and the upper case 14 and the gas flow restricting portion 210. Can be communicated through the gap between and. As a result, the pressure inside the pack case 12 can be adjusted by the circulation of air through the breathing membrane 300.

  Further, in the battery pack 10, when the pressure inside the pack case 12 is lower than the outside pressure, even if the air containing water vapor flows into the service plug cover 25 from the outside through the breathing membrane 300, the service plug cover It is possible to regulate the inflow of air containing water vapor that has flown into the inside of the pack case 12 into the pack case 12 by the gas flow regulating portion 210 integrated with the service plug housing 21 of the service plug 20. Further, even when the humidity inside the service plug cover 25 is lower than the outside humidity, air containing water vapor flows into the service plug cover 25 from the outside through the breathing membrane 300, but the gas inside the service plug cover 25 By controlling the gas flow into the pack case 12 by the gas flow restricting portion 210, the humidity in the service plug cover 25 is quickly increased and the air containing water vapor further flows into the service plug cover 25. Can be suppressed.

  As a result, in the battery pack 10 in which a temperature difference is less likely to be formed in the pack case 12 by circulating the cooling air in the pack case 12 by the blower 15, an increase in water vapor in the pack case 12 and the pack case 12 It becomes possible to satisfactorily suppress the generation of dew condensation inside the coolers 17, the main ducts 16, and the like. Further, in the battery pack 10, the air circulating in the pack case 12, that is, the air circulating in the air passage 19 may be regulated by the gas circulation regulating portion 210 from flowing into the service plug cover 25. As a result, it is possible to reduce the intake loss of each blower 15 to improve the efficiency, reduce the power consumption of each blower 15, and to use each blower 15 having a lower blowing capacity. In addition, in the battery pack 10 of the present disclosure, when the service plug cover 25 is detached from the pack case 12 for attaching / detaching the service plug 20, foreign matter is introduced through the opening 14H of the upper case 14 into the pack case 12. It is also possible to regulate the entry into the inside by the gas flow regulating portion 210.

  Further, in the battery pack 10, the gas flow restricting portion 210 is arranged in the pack case 12 so as to face the peripheral edge of the opening 14H of the upper case 14 with a gap. As a result, the gas inside the service plug cover 25 flows into the pack case 12 while allowing communication between the inside and outside of the pack case 12 through the breathing membrane 300 to enable pressure adjustment inside the pack case 12. It becomes possible to properly regulate

  Further, the service plug 20 shuts off the service plug housing 21 and an electric circuit including the plurality of battery modules 11 when the service plug housing 21 is removed from the service plug housing 21, and also when the service plug housing 21 is attached to the service plug 20. And a service plug grip 22 for releasing the interruption of the electric circuit by 20. The gas flow regulation unit 210 is integrated with the service plug housing 21. As a result, the number of parts of the battery pack 10 can be reduced. However, the gas flow restricting portion 210 may be fixed to the service plug housing 21 by being formed separately from the service plug housing 21 with resin or metal.

  As described above, the battery pack 10 of the present disclosure includes a plurality of battery modules 11, a pack case 12 accommodating the plurality of battery modules 11, and a service for disconnecting an electric circuit including the plurality of battery modules 11. The plug case, the blower 15 for circulating the cooling air in the pack case 12, the opening 14H of the pack case 12 (upper case 14) for exposing the service plug 20 to the outside, and the pack case so as to cover the service plug 20. 12, a service plug cover 25 that is detachably attached, a breathing membrane 300 provided on the service plug cover 25, and a gas flow restricting portion 210 that restricts gas inside the service plug cover 25 from flowing into the pack case 12. Including and As a result, in the battery pack 10 in which a temperature difference is less likely to be formed in the pack case 12 by circulating the cooling air in the pack case 12 by the blower 15, the increase in water vapor and the occurrence of dew condensation in the pack case 12 are prevented. It can be suppressed well.

  Further, it is needless to say that the invention of the present disclosure is not limited to the above-described embodiment, and various modifications can be made within the scope of the extension of the present disclosure. Further, the mode for carrying out the invention is merely a specific mode of the invention described in the section of means for solving the problem, and is described in the section for means for solving the problem. It does not limit the elements of the invention.

  INDUSTRIAL APPLICABILITY The invention of the present disclosure can be used in the battery pack manufacturing industry and the like.

  1 vehicle, 2 floor panel, 2H opening, 3 vehicle interior cover, 10 battery pack, 11 battery module, 110 busbar module, 12 pack case, 13 lower case, 14 upper case, 14H opening, 15 blower, 16 main Duct, 17 cooler, 18 sub-duct, 19 air passage, 20 service plug, 21 service plug housing, 210 gas flow control part, 22 service plug grip, 23 center bracket, 24 housing bracket, 25 service plug cover, 26 sealing member, 30 breathing plug, 300 breathing membrane, MG motor generator.

Claims (1)

In a battery pack including a battery module, a pack case accommodating the battery module, a service plug for interrupting an electric circuit including the battery module, and a blower for circulating cooling air in the pack case,
A service plug cover that is detachably attached to the pack case so as to cover the opening of the pack case that exposes the service plug to the outside and the service plug;
A breathing membrane provided on the service plug cover,
A gas flow restricting portion that restricts gas in the service plug cover from flowing into the pack case;
Battery pack.

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