JP2020006811A - Battery case - Google Patents

Abstract

To provide a battery case capable of inhibiting temperature rise of a refrigerant which flows in a refrigerant passage provided at a member, in which a battery is installed, and cools the battery.SOLUTION: A battery case includes: a side wall part 12a extending along a rocker in a vehicle body fore and aft direction; and a bottom part 13 on which a battery is placed. The bottom part has: an upper plate 131 on which the battery is placed and which has a refrigerant passage in which a refrigerant flows; a lower plate 133 disposed at the road surface side; and a heat insulation core material 132 sandwiched between the upper plate and the lower plate. The side wall part is connected to the bottom part while forming a gap with an end surface of the upper plate.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a battery case.

  2. Description of the Related Art Conventionally, there has been known a floor structure of a vehicle body in which a secondary battery for powering the vehicle is stored under the floor of the vehicle body (for example, see Patent Document 1).

JP-A-2004-9986

  By the way, secondary batteries and the like (hereinafter, simply referred to as "batteries") generate heat when used and require cooling. Therefore, the batteries are placed on a plate-shaped metal member and a refrigerant is flowed directly below the batteries. A structure provided with a coolant channel is under study. However, when a battery is installed under the floor of a vehicle body, heat from the outside such as road surface heat and heat of the outside air is transmitted to a metal member on which the battery is installed via a reinforcing member of the vehicle body such as a rocker or a reinforcement, and the refrigerant flow is reduced. There is a concern that the temperature of the refrigerant flowing through the path may be increased. When the temperature of the refrigerant increases, the cooling effect of the battery may decrease.

  Therefore, it is an object of the battery case disclosed in the present specification to suppress a rise in the temperature of a coolant that flows through a coolant passage provided in a member where a battery is installed and cools the battery.

  The battery case disclosed in the present specification is a battery case including a side wall portion extending in a front-rear direction of a vehicle body along a rocker, and a bottom portion on which a battery is mounted. An upper plate having a refrigerant flow path through which the refrigerant flows, a lower plate disposed on the road surface side, and a heat insulating core material sandwiched between the upper plate and the lower plate, the side wall portion includes: It is connected to the bottom part with a gap provided between it and the end face of the upper plate.

  ADVANTAGE OF THE INVENTION According to the battery case disclosed by this specification, it can flow through the refrigerant | coolant flow path provided in the member in which a battery is installed, and can suppress the temperature rise of the refrigerant | coolant which cools a battery.

FIG. 1 is an explanatory diagram schematically showing a vehicle equipped with the battery case of the first embodiment. FIG. 2 is an explanatory diagram illustrating a positional relationship between the battery case and the rocker according to the first embodiment. FIG. 3 is a perspective view showing a part of the battery case and the rocker of the first embodiment. FIG. 4 is an explanatory diagram schematically showing an overlapping state of each member at a joint portion between the first reinforcement and the lower panel of the battery case of the first embodiment. FIG. 5 is an explanatory diagram showing a cross section at a position corresponding to the line AA in FIG. 3 and enlarging and illustrating a joining portion between the first reinforcement and the lower panel. FIG. 6 is an explanatory diagram showing an enlarged view of the periphery of a gap provided between the side wall of the battery case and the end surface of the upper plate according to the first embodiment. FIG. 7 is a graph showing an example of the relationship between the amount of external heat input to the battery case and the battery temperature. FIG. 8 is a graph showing an example of the relationship between the input amount to the battery case and the reaction force of the lower panel. FIG. 9 is an explanatory diagram showing, in an enlarged manner, a joint portion between the first reinforcement and the lower panel in the comparative example. FIG. 10 is a perspective view showing a part of the battery case and the rocker of the second embodiment. FIG. 11 is a perspective view showing a part of the battery case and the rocker of the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, dimensions, ratios, and the like of each part may not be illustrated so as to completely match actual ones. In some drawings, details are omitted.

(1st Embodiment)
Referring to FIG. 1, a battery case 12 of the first embodiment houses a battery 10 and is mounted on a vehicle 100. The vehicle 100 is an electric vehicle, and the battery 10 housed in the battery case 12 is mainly used as a power source for running the vehicle 100. The vehicle 100 may be a so-called hybrid vehicle. Vehicle 100 may be a fuel cell vehicle. When the vehicle 100 is a fuel cell vehicle, the battery 10 housed in the battery case 12 is a fuel cell.

  The vehicle 100 includes a vehicle body 101, front wheels 102, rear wheels 103, a motor generator (hereinafter, referred to as “MG (Motor Generator)”) 104, and a power control unit (hereinafter, referred to as “PCU (Power Control Unit)”). 105 is provided. The front wheel 102 is mounted in a front wheel arch 101a provided in front of the vehicle body 101. The rear wheel 103 is mounted in a rear wheel arch 101b provided behind the vehicle body 101. The vehicle 100 runs using the electric power stored in the battery 10.

  MG 104 is, for example, a three-phase AC rotating electric machine. The output torque of MG 104 is transmitted to front wheels 102 or rear wheels 103 serving as driving wheels via a power transmission gear formed by a speed reducer or the like. MG 104 can also generate electric power by the rotational force of the drive wheels during the regenerative braking operation of vehicle 100.

  PCU 105 includes an invert and a convert, not shown. When the battery 10 is discharged, the converter boosts the voltage supplied from the battery 10 and supplies the boosted voltage to the inverter. The inverter drives the MG 104 by converting the DC current supplied from the converter into an AC current. On the other hand, when charging battery 10, the inverter converts the AC current generated by MG 104 into a DC current and supplies the DC current to the converter. The converter steps down the voltage supplied from the inverter and supplies it to the battery 10.

  The vehicle body 101 includes a rocker 106 extending between the front wheel arch 101a and the rear wheel arch 101b in the front-rear direction of the vehicle body 101. The lockers 106 are provided on both left and right sides of the vehicle body 101, respectively. Here, referring to FIG. 2, the battery case 12 is disposed between the left and right rockers 106. The battery case 12 is attached to a chassis (not shown) of the vehicle body 101.

  Referring to FIGS. 2 to 5, the battery case 12 includes a first reinforcement 12a, a second reinforcement 12b, and a lower panel 13. FIG. 2 shows a state in which the battery case 12 with the upper cover removed is viewed from above. The first reinforcement 12a extends in the front-rear direction of the vehicle body 101 along the rocker 106. The first reinforcement 12a corresponds to a side wall. The second reinforcement 12b extends in the left-right direction of the vehicle body 101, intersects with the first reinforcement 12a, and is joined to the first reinforcement 12a. The inside of the battery case 12 is divided into a plurality of regions by a combination of the first reinforcement 12a and the second reinforcement 12b. In the present embodiment, four regions are formed along the front-rear direction of the vehicle body 101. The joining between the first reinforcement 12a and the second reinforcement 12b can be mechanical joining such as rivet joining, screw joining, caulking joining, or metallurgical joining such as welding or welding. Further, bonding using an adhesive can also be performed.

  The lower panel 13 corresponds to the bottom of the battery case 12. The lower panel 13 includes an upper plate 131, a heat insulating core material (hereinafter, simply referred to as “core material”) 132, and a lower plate 133. The lower panel 13 has a sandwich structure in which a core material 132 is sandwiched between an upper plate 131 and a lower plate 133. The upper plate 131, the core material 132, and the lower plate 133 will be described later in detail.

  On the lower panel 13, a battery module that forms the battery 10 for each area partitioned by the first reinforcement 12a and the second reinforcement 12b is mounted. The battery 10 of the present embodiment includes battery modules 10a to 10h, and two battery modules are arranged in each area. Each of the battery modules 10a to 10h includes an assembled battery and its accessories. The assembled battery is configured by stacking a plurality of battery cells (hereinafter, simply referred to as “cells”) 11 via a spacer. The cells 11 forming the assembled battery are arranged one by one with their directions inverted, and the positive terminal of one cell 11 and another adjacent negative terminal are electrically connected by a bus bar (not shown). Thus, the plurality of cells 11 are electrically connected in series. The connection mode of the cells 11 in the assembled battery is arbitrary, and for example, the plurality of cells 11 may be electrically connected in parallel. Although the cell 11 in the present embodiment is a lithium ion battery, for example, another type of secondary battery such as a nickel-metal hydride battery may be employed. The number of areas divided by the combination of the first reinforcement 12a and the second reinforcement 12b and the number of battery modules are not limited to these, and may be appropriately determined according to the size of the vehicle 100 and the like. , Can be set.

  The battery case 12 includes a front cover 31 on the front side of the second reinforcement 12b disposed on the most front side. Further, the battery case 12 includes a back cover 32 on the rear side of the second reinforcement 12b disposed on the rearmost side. The front cover 31 and the back cover 32 are respectively joined to the second reinforcement 12b by welding. The front cover 31 and the back cover 32 may be joined to the second reinforcement 12b by mechanical joining such as rivet joining.

  In a region covered by the front cover 31, a refrigerant inlet 31a is provided. A refrigerant supply device (not shown) is connected to the refrigerant introduction port 31a, and the refrigerant flows from the refrigerant supply device to the refrigerant flow path 131a provided in the lower panel 13 through the refrigerant introduction port 31a. The refrigerant channel 131a will be described later. In the present embodiment, cooling water is employed as the refrigerant, but air (cold air) may be employed. The back cover 32 is provided with a duct 32a that communicates with the coolant channel 131a. The duct 32a is an outlet for the refrigerant.

  Next, the upper plate 131, the core member 132, and the lower plate 133 included in the lower panel 13 will be described in detail. Note that FIG. 3 shows only one of a plurality of regions partitioned by the first reinforcement 12a and the second reinforcement 12b, and the battery modules 10a and 10b arranged in that region. Only a part is drawn. FIG. 5 is an explanatory view showing a cross section at a position corresponding to the line AA in FIG. 3 and showing a joining portion between the first reinforcement 12a and the lower panel 13 in an enlarged manner. The battery modules 10a and 10b and the second reinforcement 12b are omitted.

  The upper plate 131 is located on the uppermost side of the lower panel 13 having a sandwich structure. The upper plate 131 is a metal plate-shaped member, and has a refrigerant passage 131a through which a refrigerant flows. The battery 10 is placed on the upper side of the upper plate 131. The upper plate 131 is desirably formed of a material having high thermal conductivity, and aluminum, copper, or the like can be used. The upper plate 131 of the present embodiment is an aluminum alloy plate. In order to disperse heat in the upper plate 131 and enhance the cooling effect, it is preferable to use a material having a thermal conductivity of 50 W / m · k or more.

  The core member 132 is made of a foamed resin. Examples of the foamed resin include resins having high heat insulating properties, such as foamed polyurethane, foamed polystyrene, foamed polyolefin, and foamed epoxy. Since the foamed resin is light, the weight of the lower panel 13 and thus the battery case 12 can be reduced by including the foamed resin in the core material 132. In addition, the foamed resin can have a heat insulating effect, and heat input from the outside is easily suppressed by the core material 132. Here, referring to FIG. 3, the battery case 12 mainly receives heat intrusion through the rocker 106 as indicated by an arrow H1 and heat from the road surface side as indicated by an arrow H2 in the figure. Intrusion is expected. Among these heat intrusions, the core material 132 can effectively suppress heat intrusion from the road surface side indicated by the arrow H2.

  The lower plate 133 is located on the lowermost side of the lower panel 13 having a sandwich structure. The lower plate 133 is a metal plate-shaped member. The lower plate 133 is desirably formed of a material having high rigidity. In the present embodiment, an iron steel plate is used. In order to increase the rigidity of the lower plate 133 with a thin plate, it is preferable to use a material having a Young's modulus of 100 GPa or more.

  The upper plate 131 and the core material 132 and the core material 132 and the lower plate 133 are respectively joined by adhesiveness of a foamed resin forming the core material 132. More specifically, the foamed resin filled between the upper plate 131 and the lower plate 133 arranged opposite to each other is foamed and its adhesiveness is exerted, so that the upper plate 131 and the core material 132, and the core material 132 and the lower The plates 133 are joined together.

  Here, the joining of the lower panel 13 and the first reinforcement 12a will be described mainly with reference to FIGS. The battery case 12 includes a first reinforcement 12a extending in the front-rear direction on the left side. The rocker 106 is located further to the left of the first reinforcement 12a. In the lower panel 13, the position of the end face 131 b of the upper plate 131, the position of the side edge 132 a of the core material 132, and the position of the side edge 133 a of the lower plate 133 on the left side are different. Specifically, the end face 131b of the upper plate 131 is located closest to the center of the battery case 12 (rightmost in the drawing), and the side edge 133a of the lower plate 133 is located outermost (leftmost in the drawing). I have.

  The first reinforcement 12a joined to the lower panel 13 is provided with a flange-shaped portion 12a2 protruding toward the center when focusing on the cross section shown in FIG. The end surface 12a21 of the flange portion 12a2 faces the end surface 131b of the upper plate 131, and a gap C1 is provided between the end surface 12a21 of the flange portion 12a2 and the end surface 131b of the upper plate 131. That is, the upper plate 131 is arranged so as not to contact the first reinforcement 12a. Thereby, heat transfer from the first reinforcement 12a to the upper plate 131 is suppressed. The upper plate 131 is provided with a coolant channel 131a, and the upper plate 131 is provided with the battery modules 10a to 10h forming the battery 10. , In particular, through the rocker 106 and the first reinforcement 12a as shown by the arrow H1 can be effectively suppressed.

  The first reinforcement 12a includes a cut portion 12a3 provided below the flange portion 12a2. The side edge 132a of the core material 132 enters the cut 12a3. The first reinforcement 12a and the side edge 132a of the core member 132 are joined by an adhesive. Since the side edge 132a of the core member 132 is held in the notch 12a3 so that the two overlap each other, a high bonding strength between the lower panel 13 and the first reinforcement 12a can be obtained.

  The side edge portion 133a of the lower plate 133 extends outside the side edge portion 132a of the core member 132, and the first reinforcement 12a is joined to a portion extending outside the side edge portion 132a of the core member 132. In addition, a rocker 106 is attached. The first reinforcement 12a has a portion outside the notch 12a3 in contact with the lower plate 133, and this portion is joined to the lower plate 133 by an adhesive. The side edge portion 133a of the lower plate 133 extends further outward than the outer side surface 12a4 of the first reinforcement 12a, and the rocker 106 is attached to this portion by the rivet 40. An adhesive may be applied between the locker 106 and the lower plate 133. Note that bolts and nuts may be used instead of the rivets 40.

  The first reinforcement 12a and the rocker 106 are arranged side by side. At this time, a gap C2 is provided between the side surface 12a4 of the first reinforcement 12a and the rocker 106. Thus, heat transfer from the rocker 106 to the first reinforcement 12a and, consequently, heat transfer to the upper plate 131 are suppressed.

  Referring to FIG. 6, the upper plate 131 includes a flange-shaped connection portion 131c extending toward the first reinforcement 12a. The connection portion 131c straddles the gap C1 and overlaps the flange portion 12a2 of the first reinforcement 12a, and is joined to the flange portion 12a2 by the screw 14. Thereby, the joining strength between the lower panel 13 and the first reinforcement 12a is improved.

  The battery case 12 has the same configuration on the right side. Further, the first reinforcement 12a has a hollow portion 12a1 therein for weight reduction.

  Here, the relationship between the amount of heat input (W) from the outside of the battery case 12 and the temperature (° C.) of the battery 10 will be described with reference to FIG. Referring to FIG. 7, it can be seen that the higher the heat input (W) from the outside, the higher the battery temperature (° C.). In the battery case 12 of the present embodiment, a gap C1 is provided between an end surface 131b of an upper plate 131 having a coolant channel 131a and a first reinforcement 12a extending in the front-rear direction of the vehicle body 101 along the rocker 106. I have. Therefore, heat transfer from the first reinforcement 12a to the upper plate 131 is suppressed. Further, since the lower panel 13 includes the resin core material 132, heat transfer from the road surface side to the upper plate 131 is suppressed. As a result, it is possible to suppress a rise in the temperature of the refrigerant flowing in the refrigerant flow passage 131a provided in the upper plate 131, and thus to suppress a rise in the temperature of the battery 10.

  As described above, the battery case 12 of the present embodiment can suppress an increase in the temperature of the refrigerant and an increase in the temperature of the battery 10, so that the flow rate of the refrigerant can be reduced. Therefore, the size of the pump for flowing the refrigerant can be reduced, and as a result, the weight and cost of the vehicle 100 can be reduced.

  Further, in the battery case 12 of the present embodiment, the side edge 132a of the core member 132 is gripped by the notch 12a3 provided in the first reinforcement 12a, and both are overlapped. In addition, the upper plate 131 and the first reinforcement 12a are joined via the connection portion 131c to improve the joint strength between them. Here, FIG. 8 shows an example of the relationship between the input amount (mm) to the battery case 12 and the reaction force (N) of the lower panel regarding the battery case 12 of the present embodiment and the battery case of the comparative example. ing. The input is made at a location that is easily deformed in the battery case 12 in consideration of the arrangement of the first reinforcement 12a and the second reinforcement 12b, for example, a position indicated by P in FIG. Here, the input amount (mm) is, for example, a displacement amount when the lower part of the vehicle 100 collides with a protrusion on the road and the battery case is pushed up.

  In the comparative example shown in FIG. 9, the lower panel 53 having a sandwich structure including the upper plate 531, the core member 532, and the lower plate 533 is joined to the first reinforcement 52a. At the joint, the upper plate 531 of the lower panel 53 overlaps the flange 52a2 of the first reinforcement 52a, and the end face 52a21 of the flange 52a2 and the side edge 532a of the core member 532 abut each other. In the comparative example, the strength of the joint between the lower panel 53 and the first reinforcement 52a is ensured by the upper plate 531 that is a metal member overlapping the flange 52a2 of the first reinforcement 52a.

  On the other hand, in the battery case 12 of the present embodiment, since the gap C1 is formed between the upper plate 131, which is a metal member that is easy to secure the strength, and the first reinforcement 12a, the joining by the upper plate 131 is performed. It is difficult to secure strength. Therefore, in the battery case 12 of the present embodiment, the core member 132 straddles the gap C1 and is caught in the cut portion 12a3 of the first reinforcement 12a, so that the first reinforcement 12a and the core member 132 overlap each other. To ensure the strength. In the present embodiment, the joining strength is also improved by the connecting portion 131c. Thereby, as shown in FIG. 8, in the present embodiment, it is possible to secure a strength equal to or higher than that of the comparative example.

  In the comparative example, since the upper plate 531 and the first reinforcement 52 are in contact with each other, heat is transferred to the upper plate 531 through the first reinforcement 52, and the refrigerant flow path 531a provided in the upper plate 531 is provided. The refrigerant flowing through is heated. For this reason, the cooling capacity of the battery may be reduced.

(2nd Embodiment)
Next, a second embodiment will be described with reference to FIG. Note that the same reference numerals in the drawings denote the same components as in the first embodiment, and a detailed description thereof will be omitted.

  The second embodiment includes a first reinforcement 22a instead of the first reinforcement 12a of the first embodiment. In the second embodiment, a lower panel 23 is provided instead of the lower panel 13 of the first embodiment.

  The first reinforcement 22a is common to the first reinforcement 12a of the first embodiment in that the first reinforcement 22a includes a hollow portion 22a1 and a flange portion 22a2, but is not provided with a cut portion. It is different from one reinforcement 12a. Further, the lower panel 23 is common to the lower panel 13 of the first embodiment in that the lower panel 23 has a sandwich structure including an upper plate 231, a heat insulating core material (hereinafter, simply referred to as a “core material”) 232, and a lower plate 233. The position of the side edge portion 232a of the core member 232 is different. Specifically, due to the fact that the first reinforcement 22a does not have a cut portion, the side edge portion 232a is brought into contact with the end face 22a21 of the flange 22a2 of the first reinforcement 22a. I have.

  Further, unlike the first embodiment, the second embodiment does not include a configuration corresponding to the connection portion 131c.

  On the other hand, the side edge portion 233a of the lower plate 233 extends to the lower side of the rocker 106 and is joined to the rocker 106 by the rivets 40 in common with the first embodiment. Further, the point that the upper plate 231 is provided with the refrigerant flow path 231a and the gap C1 is provided between the end face 231b and the end face 22a21 of the flange 22a2 provided in the first reinforcement 22a is the same as in the first embodiment. . Therefore, in the second embodiment, similarly to the first embodiment, heat transfer from the first reinforcement 22a to the upper plate 231 is suppressed. As a result, the temperature rise of the battery can be suppressed.

  In the second embodiment, unlike the first embodiment, the first reinforcement 22a does not have a cut portion, and the core member 232 does not have a structure in which the first reinforcement 22a is held by the first reinforcement 22a. Therefore, it is difficult to secure the strength. In addition, it is difficult to secure the strength even in a point that it does not have a configuration corresponding to the connection portion 131c in the first embodiment. Therefore, the thickness of the core material 232 may be increased to secure a desired strength.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. Note that the same reference numerals in the drawings denote the same components as in the second embodiment, and a detailed description thereof will be omitted.

  The third embodiment includes a reinforcing member 50 that straddles the gap C1 and connects the first reinforcement 22a and the lower panel 23. Thereby, the strength of the connecting portion between the first reinforcement 22a and the lower panel 23 can be improved. The reinforcing member 50 may be mounted using bolts or rivets, but in the present embodiment, an adhesive is used to suppress heat transfer. In this embodiment, the reinforcing member 50 is provided on the basis of the second embodiment. However, the reinforcing member 50 may be provided on the basis of the first embodiment.

  The above embodiment is merely an example for carrying out the present invention, and the present invention is not limited to these. Various modifications of these examples are within the scope of the present invention, and the present invention is further described. It is obvious from the above description that various other embodiments are possible within the scope.

DESCRIPTION OF SYMBOLS 10 Battery 10a-10h Battery module 11 Battery cell 12 Battery case 12a, 22a 1st reinforcement (side wall part)
12a1, 22a1 Cavity 12a2, 22a2 Flange 12a21, 22a21 End 12a3 Cut 12a4 Side 12b Second reinforcement 13, 23 Lower panel (bottom)
131, 231 Upper plate 131a, 231a Refrigerant flow path 131b, 231b End face 131c Connection part 132, 232 Insulating core material 132a, 232a Side edge 133, 233 Lower plate 133a, 233a Side edge 50 Reinforcement member 100 Vehicle 101 Vehicle 101a Front side Wheel arch 101b Rear wheel arch 106 Rocker C1, C2 Clearance

Claims (1)

A battery case including a side wall portion extending in the front-rear direction of the vehicle body along the rocker, and a bottom portion on which the battery is mounted,
The bottom portion, on which the battery is mounted, an upper plate having a refrigerant flow path through which a refrigerant flows, a lower plate disposed on the road surface side, and a heat insulating core material sandwiched between the upper plate and the lower plate, Has,
The battery case, wherein the side wall portion is joined to the bottom portion with a gap provided between the side wall portion and an end surface of the upper plate.

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