JP6477366B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack mounted on an electric vehicle.

  Conventionally, battery packs mounted on electric vehicles such as hybrid vehicles and electric vehicles are known. The battery pack is a pack in which one or more battery stacks are accommodated in a battery case. The battery stack is configured by alternately stacking a plurality of battery cells, which are secondary batteries, and resin frames.

JP 2014-238987 A

  In recent years, it has been proposed to install such a battery pack in a vehicle interior, for example, below a seat. With such a configuration, while the space of the vehicle can be effectively used, moisture spilled into the vehicle interior or foreign matter in the vehicle interior may enter the battery case and come into contact with the battery cell. As described above, when moisture or foreign matter comes into contact with the battery cell in the battery case, the battery cell may be damaged. Of course, these problems can be solved by making the gap between the battery cases as small as possible. However, the battery case is usually composed of a plurality of members instead of a single member. For this reason, gaps are apt to be generated around the joints between the members.

  Patent Document 1 discloses a technique for preventing foreign matter from entering a bus bar case. That is, the plurality of battery cells constituting the battery stack are electrically connected in series by the plurality of bus bars. The plurality of bus bars are accommodated in a bus bar case (bus bar case) and further covered with a bus bar cover. In Patent Document 1, in order to prevent the entry of foreign matter into the bus bar case, a locking claw that is bent in the direction of the accommodating space of the bus bar is provided at the front end of the bus bar case, and the locking claw is locked to the cover. It is disclosed that a locking hole is provided. According to such a technique, entry of foreign matter into the bus bar case is effectively prevented. However, the technique of Patent Document 1 is a technique related to a bus bar case to the last, and is difficult to apply to a battery case.

  Therefore, an object of the present invention is to provide a battery pack that can more reliably prevent contact of foreign matter and water with battery cells in a battery case.

The battery pack of the present invention is a battery pack mounted on an electric vehicle, and includes at least one battery stack in which a plurality of battery cells and a resin frame are alternately stacked, and a battery case that houses the at least one battery stack. The battery case includes: a lower case on which the one or more battery stacks are placed; an upper cover that is attached to the lower case and covers an upper side and a front side of the one or more battery stacks; A bracket that crosses a path connecting the gap between the front end face of the upper cover and the front end face of the lower case, and the plurality of battery cells, and prevents foreign matter from entering through the gap, and The front end surface of the lower case has a non-reinforcing portion where no reinforcing member is arranged and a reinforcing portion where the reinforcing member overlaps in the thickness direction arranged in the left-right direction. It is provided at a position overlapping with the joint of a strong portion and the reinforcing portion, characterized in that.

  According to the present invention, by providing the bracket that crosses the path connecting the gap between the front end face of the upper cover and the front end face of the lower case and the plurality of battery cells, entry of foreign matter from the gap is inhibited. Is done. As a result, it is possible to more reliably prevent foreign matter and water from contacting the battery cells in the battery case.

It is a schematic exploded perspective view which shows the structure of the battery pack of this invention. It is a perspective view which shows the state which laminated | stacked the battery cell and the resin frame. It is a schematic sectional drawing of the battery pack in the horizontal direction approximate center position. It is a schematic sectional drawing of the battery pack in a transition part. It is a figure which shows the mode of the test | inspection using the probe for a proximity test. It is a figure which shows an example of another battery pack.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing a schematic configuration of a battery pack 10 according to an embodiment of the present invention. The battery pack 10 is mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle, and outputs electric power necessary for driving the vehicle. Such a battery pack 10 may be installed anywhere in the vehicle, but the battery pack 10 of the present embodiment has a configuration that is particularly suitable for installation in a vehicle interior, for example, in the lower part of a seat. ing. Hereinafter, the battery pack 10 installed so that the stacking direction of the battery cells is the vehicle left-right direction and the two battery stacks 30 are disposed in the vehicle front-rear direction will be described as an example.

  The battery pack 10 is a pack in which parts such as the battery stack 30 are accommodated in a battery case 12. The parts accommodated in the battery case 12 include a plurality of battery stacks 30, a bus bar module for electrically connecting a plurality of battery cells, a duct communicating with the inside and outside of the battery case 12, and a large number of wires. A wiring protector for holding the battery stack, a fastener for fastening the battery stack 30 to the battery case 12, and fastening the battery case 12 to the vehicle body. In FIG. 1, only the battery stack 30 is illustrated as a component housed in the battery case 12 in order to facilitate understanding of the invention.

  In the present embodiment, two battery stacks 30 are arranged in parallel. In FIG. 1, the arrangement direction of the two battery stacks 30 is the front-rear direction of the vehicle body (the lower left direction in FIG. 1 is the front direction), and the longitudinal direction of the battery stack 30 is the left-right direction of the vehicle body (the upper left direction in FIG. Way). Each battery stack 30 is configured by alternately stacking a plurality of battery cells and a resin frame. FIG. 2 is a perspective view showing a state in which the battery cell 32 and the resin frame 40 are stacked.

  The battery cell 32 is a chargeable / dischargeable secondary battery, such as a nickel metal hydride battery or a lithium ion battery. The battery cell 32 has a substantially rectangular parallelepiped battery case 34, and a pair of cell terminals 36 protrude from the upper end surface of the battery case 34. Each cell terminal 36 is connected to a bus bar (not shown) that is a metal plate, and a plurality of battery cells 32 are electrically connected in series via the bus bar. Further, a gas discharge port 38 for discharging gas generated in the battery case 34 is also formed between the pair of cell terminals 36 on the upper end surface of the battery case 34. The gas discharge port 38 is configured, for example, by closing an opening formed in the upper end surface of the battery case 34 with a metal thin film.

  The resin frame 40 is a member made of an insulating resin. The resin frame 40 includes a frame main body 42 disposed between the battery cells 32, side walls 44 connected to both ends in the width direction of the frame main body 42, and a connecting portion 46 protruding from the upper end surface and the lower end surface of the frame main body 42. And. A plurality of grooves (not shown) are formed on the surface of the frame body 42, and these grooves serve as cooling air flow paths. One end of the cooling air flow path is connected to the lower end of the frame main body 42, and the other end is connected to the width direction end of the frame main body 42, and the cooling air flowing from the lower end of the frame main body 42 follows the cooling air flow path. And then flows out of the stack body from both ends in the width direction. The cooling air takes heat from the battery cells 32 in the process of flowing along the cooling air flow path.

  Two pairs of connecting portions 46 are provided on the upper end surface and the lower end surface of the frame main body 42, one pair each. The pair of connecting portions 46 are arranged at intervals in the width direction. Each connecting portion 46 protrudes in the thickness direction of the resin frame 40, and is set to have a thickness so as to be in contact with the connecting portion 46 of the adjacent resin frame 40 as shown in FIG. A through-hole penetrating in the thickness direction is formed in the connecting portion 46, and a restraining band that restrains the plurality of battery cells 32 and the resin frame 40 is inserted through the through-hole.

  Further, the height of the connecting portion 46 is a height at which the connecting portion 46 can contact the top surface or the bottom surface of the battery case 12. Therefore, when the battery stack 30 is accommodated in the battery case 12, the upper side of the battery stack 30 is surrounded by the pair of connecting portions 46, the top surface of the battery case 12, and the top surface of the battery case 34, and extends in the stacking direction. A passage is formed. This passage becomes a smoke exhaust passage through which gas (smoke exhaust) discharged from the battery case 34 passes. Similarly, a path extending in the stacking direction is formed below the battery stack 30 by being surrounded by the pair of connecting portions 46, the bottom surface of the battery case 12, and the bottom surface of the battery case 34. This passage becomes a cooling air passage through which the cooling air for cooling the battery cell 32 passes.

  Next, the configuration of the battery case 12 will be described with reference to FIG. 1 again. The battery case 12 is a box-shaped member that is open at both left and right ends. Ducts that communicate with the inside and outside of the battery case 12, wiring passages, and the like are disposed at the opening portions at the left and right ends. The battery case 12 includes a lower case 14 and an upper cover 16 that is detachably attached to the lower case 14.

  The lower case 14 further includes a case main body 18 and a plurality of reinforcing members 20 attached to the case main body 18. The case body 18 is a sheet metal member formed by bending a metal plate or the like. The case main body 18 includes a main body bottom plate 18b on which a plurality of battery stacks 30 and the like are placed, a main body rear wall 18r standing from the rear end of the main body bottom plate 18b, and a main body front wall 18f standing from the front end of the main body bottom plate 18b. It is equipped with. The main body rear wall 18r has substantially the same height as the battery stack 30, and a fastening portion that is fastened to the upper cover 16 is provided at the tip thereof.

  The main body front wall 18 f is a wall that is sufficiently lower than the battery stack 30. The reason why the main body front wall 18f is lowered is to ensure workability at the time of assembling the battery stack 30 and the like. That is, when assembling the battery stack 30 or the like, the worker accesses the battery case 12 from the front side of the battery case 12. At this time, if the front wall 18f of the main body is excessively high, the line of sight is blocked or the movement of the hands and arms is disturbed. Therefore, in the present embodiment, the main body front wall 18f is lowered to facilitate access from the front side to the inside of the case. However, as will be described later, in order to prevent foreign matter and water from entering the battery case 12, the main body front wall 18f must overlap with a cover front wall 16f described later in the height direction. Therefore, the main body front wall 18f has a height that can overlap with the cover front wall 16f in the height direction, which will be described in detail later.

  The reinforcing member 20 is a member that is attached to the outside of the case body 18 and partially reinforces the case body 18. In the present embodiment, reinforcing members 20 are provided near the left and right ends of the case body 18. In the vicinity of both left and right ends, a fastening portion for attaching the battery stack 30 to the battery case 12, a fastening portion for attaching the battery case 12 to the vehicle body, and the like are located. Since the fastening portion is often subjected to a larger load than other portions, in this embodiment, the reinforcing member 20 is provided to reinforce the case main body 18.

  The reinforcing member 20 is a sheet metal member formed by bending a metal plate thicker than the case body 18. The reinforcing member 20 disposed on the front side has a substantially L-shaped cross section including a reinforcing bottom plate 20b disposed so as to overlap with the main body bottom plate 18b, and a reinforcing front wall 20f standing from the front end of the reinforcing bottom plate 20b. Yes. As shown in FIG. 1, the reinforcing front wall 20f is located on the front side of the main body front wall 18f. That is, in the place where the reinforcing member 20 is disposed, the front surface of the reinforcing front wall 20f is the front end face of the lower case 14, and in other places, the front face of the main body front wall 18f is the front end face of the lower case 14. Become. From another viewpoint, it can be said that the front end face of the lower case 14 protrudes forward in the vicinity of both left and right ends.

  The reinforcing front wall 20f basically has the same height as the main body front wall 18f, but is sufficiently lower than the main body front wall 18f at the left and right inner ends (portion 21 in FIG. 1). It has become. The reason for this configuration is to avoid interference with the upper cover 16, which will be described in detail later.

  The upper cover 16 is also a sheet metal member formed by bending a metal plate, and includes a top plate 16t that covers the upper side of the battery stack 30 and a cover front wall 16f that hangs down from the front end of the top plate 16t. It is L-shaped. The assembly work of the battery stack 30 and the like is performed with the upper cover 16 removed. The upper cover 16 is attached to the lower case 14 after the assembly work is completed.

  The cover front wall 16f is a wall that covers the front surface of the battery case 12 in cooperation with the main body front wall 18f and the reinforcing front wall 20f and prevents entry of foreign matter and water into the case. In particular, when the conductive member comes into contact with the battery cell 32, there is a possibility that the battery pack 10 may be electrically and mechanically damaged. For this reason, the cover front wall 16f cooperates with the main body front wall 18f and the reinforcing front wall 20f to prevent the conductive foreign matter from contacting the battery cell 32. The cover front wall 16f hangs down to the vicinity of the lower end of the battery case 12. When the upper cover 16 is attached to the lower case 14, the cover front wall 16f, as a rule, overlaps with the main body front wall 18f or the reinforcing front wall 20f in the height direction.

  The cover front wall 16f is disposed close to the front end surface of the lower case 14 so that a gap allowing entry of foreign matter cannot be formed between the front wall 16f and the front end surface of the lower case 14. Here, as described above, the front end surface of the lower case 14 protrudes to the front side in the vicinity of both left and right ends, specifically, at the location where the reinforcing member 20 is disposed. Therefore, the cover front wall 16f also bulges out and protrudes to the front side in the vicinity of both left and right ends in accordance with the front end surface of the lower case 14. In this way, by inflating the front cover wall 16f forward along the front end surface of the lower case 14, it is possible to prevent foreign matter from entering while preventing interference between the front cover wall 16f and the reinforcing front wall 20f.

  However, in the joint portion of the cover front wall 16f that is close to the main body front wall 18f and the portion that is close to the reinforcing front wall 20f (portion 17 in FIG. 1, hereinafter referred to as “transition portion 17”), It was difficult to prevent interference with the reinforcing front wall 20f while preventing foreign matter from entering. Therefore, in the transition portion 17, the height of the reinforcing front wall 20 f is reduced so that the reinforcing front wall 20 f and the main body front wall 18 f do not overlap in the height direction. In this case, although interference between the reinforcing front wall 20f and the main body front wall 18f can be prevented, there is a possibility that intrusion of foreign matter cannot be prevented.

  Therefore, in the present embodiment, the bracket 22 for preventing the entry of foreign matter is provided in the transition portion 17 in the inner surface of the main body front wall 18f. Hereinafter, this will be described with reference to FIGS. FIG. 3 is a schematic cross-sectional view of the battery pack 10 at a substantially central position in the left-right direction, that is, at a location where the main body front wall 18 f becomes the front end surface of the lower case 14. FIG. 4 is a schematic cross-sectional view of the battery pack 10 at the transition portion 17. 3 and 4, reference numeral 28 denotes a sealing member that hermetically seals the connecting portion 46 and the battery case 12.

  As shown in FIG. 3, in this case, the cover front wall 16f is positioned immediately in front of the main body front wall 18f, and only a very small gap is opened between the cover front wall 16f and the main body front wall 18f. . The cover front wall 16f extends from the upper end of the main body front wall 18f to the lower side. In other words, the cover front wall 16f and the front end surface of the lower case 14 are overlapped in the height direction. As described above, since the gap between the cover front wall 16f and the main body front wall 18f is small, most foreign matters cannot enter the case.

  Of course, if it is very long like a wire, it may be inserted into the gap between the cover front wall 16f and the main body front wall 18f. However, even if the wire-like object 100 is inserted into the gap from below, the traveling direction is limited almost directly above, so that the wire-like object hardly comes into contact with the battery cell 32.

  On the other hand, in the transition portion 17, as described above, the front-rear direction position of the cover front wall 16f changes between a position close to the main body front wall 18f and a position close to the reinforcing front wall 20f. In the transition portion 17, if the cover front wall 16f and the reinforcing front wall 20f overlap in the height direction, they may interfere with each other. Therefore, in the present embodiment, as shown in FIG. 4, in the transition portion 17 (the portion 21 of the lower case 14), the height of the reinforcing front wall 20f is lower than the lower end of the cover front wall 16f. Thus, the reinforcing front wall 20f and the cover front wall 16f are not overlapped in the height direction. In such a configuration, interference between the reinforcing front wall 20f and the cover front wall 16f can be prevented, while foreign matter enters from the gap between the cover front wall 16f, the main body front wall 18f, and the reinforcing front wall 20f, and the battery There was a risk of contact with the cell 32.

  FIG. 5 is a diagram showing a state of inspection using the proximity inspection probe 102. The proximity inspection probe 102 is for inspecting whether a finger or a hand touches a primary part of the power source, for example, the battery cell 32 or the like, and has a wire-like contact 104 that bends flexibly. doing. As shown in FIG. 5, in the transition portion 17, since a vertical gap is generated between the main body front wall 18 f and the reinforcing front wall 20 f, the contact 104 can be inserted through this gap. And if there is no bracket 22 mentioned later, it turns out that the contact 104 can contact the battery cell 32, without bending the contact 104 depending on an angle. Further, it can be seen that if the contact 104 is bent with the end of the cover front wall 16f as a fulcrum, the contact 104 can reach the vicinity of the upper end of the battery cell 32, that is, the location where the cell terminal 36 and various wires are located. .

  As described above, when the wire-like foreign matter comes into contact with the battery cell 32 or the wiring connected to the battery cell 32, the battery pack 10 is electrically and mechanically damaged. In particular, in the present embodiment, as described above, the smoke exhaust passage 50 and the cooling air passage 52 are provided on the upper side and the lower side of the battery stack 30. Therefore, it is not necessary to separately provide a fluid passage on the front side of the battery stack 30. In this case, there is a merit that the front-rear width of the battery pack 10 can be reduced, but there is a demerit that a wire-like object entering from the front side easily reaches the battery cell 32.

  Therefore, in the present embodiment, in order to prevent such a wire-like material from contacting the battery cell 32, a path connecting the gap between the upper cover 16 and the lower case 14 and the battery cell 32 is formed in the transition portion 17. A bracket 22 that crosses and prevents entry of foreign matter is provided. The bracket 22 is a substantially L-shaped member having a base plate 22b fixed to the inner surface of the cover front wall 16f and a protruding plate 22p protruding rearward (battery stack 30 side) from the lower end of the base plate 22b. is there. In the present embodiment, the bracket 22 is connected to a straight line L1 (see FIG. 4) connecting the upper end of the reinforcing front wall 20f and the lower end of the battery cell 32, and a straight line connecting the lower end of the cover front wall 16f and the upper end of the battery cell 32. It is set as the magnitude | size which crosses the area | region enclosed by L2.

  When such a bracket 22 is provided, the wire-like foreign matter that has entered from the gap between the upper cover 16 and the lower case 14 comes into contact with the bracket 22 before reaching the battery cell 32 as shown in FIG. Invasion is inhibited. As a result, the contact of the wire foreign matter to the battery cell 32 is reliably prevented.

  In the present embodiment, the L-shaped bracket 22 is provided on the cover front wall 16f. However, if the gap between the upper cover 16 and the lower case 14 and the path connecting the battery cells 32 can be traversed, You may provide the bracket 22 of another shape in another location. For example, as shown in FIG. 6, a flat bracket 22 extending upward may be attached to the main body front wall 18f. However, it is expected that if there is a flat bracket 22 protruding upward, it will interfere with the work of assembling the battery stack 30 and the like. Therefore, when the flat bracket 22 is used, it is desirable that the flat bracket 22 has a retrofitting configuration that is attached to the main body case after all the assembly operations are completed. In addition, the insulating resin film that covers the entire battery case 34 may be omitted if the bracket 22 that inhibits the entry of foreign matter is provided. Thereby, the further cost reduction of the battery pack 10 is attained.

  10 Battery pack, 12 Battery case, 14 Lower case, 16 Upper cover, 16f Cover front wall, 16t Top plate, 17 Transition part, 18 Case body, 18b Body bottom plate, 18f Body front wall, 18r Body rear wall, 20 Reinforcement Member, 20b Reinforced bottom plate, 22 Bracket, 30 Battery stack, 32 Battery cell, 34 Battery case, 36 Cell terminal, 38 Gas outlet, 40 Resin frame, 42 Frame body, 44 Side wall, 46 Connecting part, 50 Smoke exhaust passage, 52 Cooling air passage, 100 wire-like object, 102 proximity inspection probe, 104 contactor.

Claims (1)

A battery pack mounted on an electric vehicle,
One or more battery stacks in which a plurality of battery cells and resin frames are alternately stacked;
A battery case that houses the one or more battery stacks;
With
The battery case is
A lower case on which the one or more battery stacks are placed;
An upper cover attached to the lower case and covering the top and front of the one or more battery stacks;
A bracket that crosses a path connecting the gap between the front end face of the upper cover and the front end face of the lower case, and the plurality of battery cells, and inhibits foreign matter intrusion from the gap;
With
The front end surface of the lower case has a non-reinforcing portion where no reinforcing member is arranged and a reinforcing portion where the reinforcing member overlaps in the thickness direction, arranged in the left-right direction,
The bracket is provided at a location overlapping with a joint between the non-reinforcing portion and the reinforcing portion.
A battery pack characterized by that.

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