JP7212564B2 - automotive battery - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle battery, and more particularly to a vehicle battery having bus bars connecting a plurality of battery cells.

A vehicle battery has a large number of plate-shaped battery cells inside. Patent Literature 1 describes this type of vehicle-mounted battery.

Specifically, in the battery module described in Patent Document 1, external terminals of a plurality of unit cells are electrically connected to each other by busbars. It also has a heat transfer cover that is in direct contact with the busbar and covers the busbar. Furthermore, the heat transfer cover is a thermally conductive member having insulating properties, and is in direct contact with the battery container of the single battery cell. As a result, the heat generated in the electrode group during charging and discharging is efficiently transferred to the surface of the battery container, so that the unit cells can be effectively cooled and the size of the battery module can be reduced. Here, the busbar in Patent Document 1 corresponds to the busbar of the present invention.

JP 2013-80625 A

However, in the battery module according to the background art described above, there is a problem that measures against moisture are not necessarily sufficient depending on the temperature and humidity conditions of the atmosphere surrounding the battery module.

Specifically, when the external atmosphere surrounding the battery module is in a humid state and there is a large temperature difference between the busbars of the battery module and the external atmosphere, the moisture contained in the external atmosphere may spread on the surfaces of the busbars. Condensation. If this dew condensation water flows into the battery cell side, there is a risk of causing a short circuit or failure of the battery cell.

In addition, the busbars generate heat during charging and discharging of the battery modules. In particular, since the joint portion where the bus bar is joined to another member by bolts or the like is an interface of different materials with high electrical resistance, a large amount of heat is generated when a large current flows through the joint portion. Therefore, in order to further improve the performance and life of the battery cells, it is desirable to have a configuration that can further improve the heat dissipation of the busbars.

The present invention has been made in view of such problems, and an object of the present invention is to further improve heat dissipation during charging and discharging of a battery module, and to prevent electric leakage and short circuit due to dew condensation water. The purpose is to provide an in-vehicle battery that ensures safety in a vehicle.

The battery for vehicle use of the present invention comprises a plurality of battery cells having external connection terminals, an end plate disposed on the end side in the direction in which the battery cells are aligned and made of a good heat conductor, a bus bar electrically connected to the external connection terminal and having the other end arranged above the end plate; a heat transfer plate through which the A gap between the holder and the holder is covered with the sheet.

Further, the vehicle-mounted battery of the present invention is characterized by having a wall-shaped portion formed on the outer peripheral portion of the holder.

Further, in the vehicle-mounted battery of the present invention, a groove is formed in the upper surface of the holder so as to surround the busbar.

Further, in the vehicle battery of the present invention, a difference in height is formed in the groove.

Further, in the vehicle battery of the present invention, the bottom surface of the groove is an inclined surface.

Further, in the vehicle battery of the present invention, the end plate is formed with a fin structure.

Further, in the vehicle-mounted battery of the present invention, the upper surface of the end plate is inclined downward toward the outside.

The battery for vehicle use of the present invention comprises a plurality of battery cells having external connection terminals, an end plate disposed on the end side in the direction in which the battery cells are aligned and made of a good heat conductor, a bus bar electrically connected to the external connection terminal and having the other end arranged above the end plate; a heat transfer plate through which the A gap between the holder and the holder is covered with the sheet. Thus, according to the automotive battery of the present invention, the heat transfer plate is interposed between the end plate and the bus bar, so that the heat generated from the bus bar can be actively conducted to the end plate, and the bus bar It can prevent overheating. Furthermore, since the holder is placed around the heat transfer plate and the gap between the heat transfer plate and the holder is covered with a sheet, even if dew condensation occurs on the surface of the bus bar, the dew condensation water passes through the upper surface of the sheet. to the holder. Therefore, it is possible to prevent inadvertent conduction between the busbar and the end plate due to dew condensation water.

Further, the vehicle-mounted battery of the present invention is characterized by having a wall-shaped portion formed on the outer peripheral portion of the holder. Thus, according to the vehicle-mounted battery of the present invention, the wall-like portion is provided on the outer peripheral portion of the holder, so that the wall-like portion can prevent the condensed water from flowing out to the outside.

Further, in the vehicle-mounted battery of the present invention, a groove is formed in the upper surface of the holder so as to surround the busbar. Thus, according to the vehicle battery of the present invention, the condensed water can be stored in the groove of the holder and prevented from flowing out to the outside.

Further, in the vehicle battery of the present invention, a difference in height is formed in the groove. Thus, according to the vehicle-mounted battery of the present invention, by forming a difference in height in the bottom of the groove, it is possible to prevent the condensed water stored in the groove from flowing to the battery side.

Further, in the vehicle battery of the present invention, the bottom surface of the groove is an inclined surface. Thus, according to the vehicle-mounted battery of the present invention, by making the bottom surface of the groove an inclined surface, it is possible to prevent the condensed water stored in the groove from flowing to the battery side.

Further, in the vehicle battery of the present invention, the end plate is formed with a fin structure. As a result, according to the vehicle-mounted battery of the present invention, the fin structure of the end plate can promote heat dissipation from the end plate.

Further, in the vehicle-mounted battery of the present invention, the upper surface of the end plate is inclined downward toward the outside. As a result, according to the vehicle battery of the present invention, since the upper surface of the end plate is a slanted surface, the slanted surface is used to guide the condensed water outward, allowing the condensed water to enter the battery cell side. can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the vehicle provided with the vehicle battery which concerns on embodiment of this invention, (A) is a perspective view, (B) is a top view. 1 is a perspective view showing an in-vehicle battery according to an embodiment of the present invention; FIG. 1 is an exploded perspective view showing an in-vehicle battery according to an embodiment of the present invention; FIG. 1 is a diagram showing an automotive battery according to an embodiment of the present invention, where (A) is a front view, and (B) is an enlarged cross section taken along line AA of the automotive battery shown in (A). It is a diagram. FIG. 4 is an enlarged cross-sectional view showing a vehicle-mounted battery according to another embodiment of the present invention; FIG. 4 is an enlarged cross-sectional view showing a vehicle-mounted battery according to another embodiment of the present invention; FIG. 4 is an enlarged cross-sectional view showing a vehicle-mounted battery according to another embodiment of the present invention; FIG. 4 is an enlarged cross-sectional view showing a vehicle-mounted battery according to another embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, vehicle-mounted batteries according to embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the front, back, and rear refer to the directions in which the battery cells 11 are stacked in the vehicle battery 10 . The left-right direction is the left-right direction when vehicle-mounted battery 10 is viewed from the front.

FIG. 1A is a perspective view illustrating a vehicle 30 equipped with an in-vehicle battery 10. FIG. FIG. 1(B) is a plan view illustrating an arrangement state of the vehicle-mounted battery 10. FIG.

As shown in FIG. 1A, a vehicle 30 such as an automobile or a train is equipped with an on-vehicle battery 10 (see FIG. 1B) for supplying electric power to a motor and various electrical components. When the vehicle 30 is an automobile, EV (Electrical Vehicle) vehicles, HEV (Hybrid Electrical Vehicle) vehicles, PHEV (Plug-in Hybrid Electrical Vehicle) vehicles, and the like have become popular in recent years. These vehicles 30 are also equipped with a plurality of in-vehicle batteries 10 having a high power storage function.

A vehicle 30 includes a vehicle body 31, a plurality of vehicle batteries 10 arranged in a battery arrangement area 32 defined in the vicinity of a bottom surface 33 of the vehicle 30, and a drive motor driven by electric power supplied from the vehicle battery 10. (not shown) and tires (not shown) that are rotated by the drive force of the drive motor.

As shown in FIG. 1B, a plurality of onboard batteries 10 are arranged in a matrix in a battery arrangement area 32 of a vehicle 30 . The in-vehicle battery 10 has, for example, a rectangular parallelepiped shape, and its longitudinal direction is arranged along the front-rear direction of the vehicle 30 . A plurality of vehicle-mounted batteries 10 are efficiently arranged in the battery arrangement area 32, and a large number of vehicle-mounted batteries 10 are mounted, so that the continuous running distance of the vehicle 30 can be extended.

Specifically, in the battery arrangement area 32 of the vehicle 30, two vehicle-mounted batteries 10 are arranged in the front row. On the other hand, from the second row to the fourth row, four vehicle-mounted batteries 10 are arranged in each row. The vehicle batteries 10 are electrically connected to each other via a connection bus bar 28 which will be described later.

FIG. 2 is a perspective view of the vehicle-mounted battery 10 viewed from the upper front side. The vehicle battery 10 has a plurality of battery cells 11 arranged in the front-rear direction. Vehicle-mounted battery 10 as a whole has a substantially rectangular parallelepiped shape elongated in the front-rear direction.

The battery cell 11 is, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery, and each battery cell 11 has a substantially plate shape.

The bus bar 13 is connecting means for electrically connecting the battery cells 11 to each other. The bus bar 13 is a plate-like metal member made of metal such as aluminum or copper and bent into a predetermined shape. The rear portion of the busbar 13 is electrically connected to the connection terminal of each battery cell 11 via the cell busbar 22 . Although two cell bus bars 22 are shown here, the cell bus bars 22 are provided corresponding to all the battery cells 11 . A front portion of the bus bar 13 is arranged on the upper surface of the end plate 12 .

Stud bolt 21 is a member that penetrates the front portion of bus bar 13 . Vehicle-mounted battery 10 is electrically connected to another vehicle-mounted battery 10 (not shown) via stud bolt 21 .

The end plates 12 are plate-like members arranged at both ends of the vehicle battery 10 in the front-rear direction. Specifically, the end plates 12 are arranged on the front side of the battery cell 11 arranged in the foremost position and on the rear side of the battery cell 11 arranged in the rearmost position. Here, the end plate 12 arranged behind the battery cell 11 is not illustrated. By arranging the end plates 12 at both ends in the front-rear direction, it is possible to suppress changes in the dimensions of the vehicle battery 10 in the front-rear direction due to expansion of the battery cells 11 due to temperature changes. As a material of the end plate 12, a good heat conductor having a rigidity capable of suppressing expansion deformation of the battery cell 11 and capable of conducting heat from the bus bar 13 well can be adopted. As a specific material for the end plate 12, for example, a metal such as aluminum can be used.

A fin structure 20 is formed on the upper front portion of the end plate 12 . The fin structure 20 is formed from a plurality of rib-like portions projecting forward from the front surface of the fin structure 20 . By forming the fin structure 20, the surface area of the upper front portion of the end plate 12 can be increased to facilitate heat exchange between the end plate 12 and the outside atmosphere. Although not shown here, the fin structure 20 is also formed on the upper outer surface portion of the end plate 12 arranged at the rear end of the vehicle battery 10 .

The holder 16 is a substantially frame-shaped member arranged on the upper surface of the end plate 12 . As a material for the holder 16, a resin or the like having insulating properties can be used.

FIG. 3 is an exploded perspective view showing the vehicle battery 10. As shown in FIG. Referring to this figure, a heat transfer plate 14, a holder 16, a sheet 15 and a bus bar 13 are arranged on the upper surface of the end plate 12 from below.

The heat transfer plate 14 is a plate-shaped member made of a good heat conductor, and has its lower surface in contact with the upper surface of the end plate 12 and its upper surface in contact with the lower surface of the bus bar 13 via the sheet 15 . As specific materials for the heat transfer plate 14, metals, synthetic resins such as acryl, rubber, gel-like substances, and the like can be used. The upper surface of the heat transfer plate 14 is arranged substantially flush with the upper surface of the inner edge of the holder 16 .

The holder 16 is a substantially frame-shaped member made of resin, and a wall-shaped portion 17 is formed on the periphery thereof. A groove 18 shown in FIG. 4B is formed by recessing the inside of the upper surface of the holder 16 . A rectangular opening 26 is formed in the center of the holder 16 when the holder 16 is viewed from above. The heat transfer plate 14 is accommodated in the opening 26 (see FIG. 3).

The sheet 15 is a thin rectangular resin sheet made of resin such as PP (polypropylene), and is arranged on the upper surfaces of the holder 16 and the heat transfer plate 14 and contacts the lower surface of the bus bar 13 . The sheet 15 has a substantially rectangular shape that is larger than the opening 26 of the holder 16 . That is, the seat 15 is formed slightly larger than the opening 26 of the holder 16 in the front-rear direction and the left-right direction. With the sheet 15 having such a configuration, the boundary between the heat transfer plate 14 and the holder 16 can be covered with the sheet 15 . Further, an adhesive layer is formed on the lower surface of the sheet 15 for adhering to the upper surfaces of the holder 16 and the heat transfer plate 14 .

The bus bar 13 is, as described above, connecting means for connecting the battery cells 11 shown in FIG. A front portion of the bus bar 13 extends in the left-right direction along the upper surface of the end plate 12 . As will be described later, the front portion of bus bar 13 is thermally coupled to end plate 12 via sheet 15 and heat transfer plate 14, so that even if bus bar 13 becomes hot during charge/discharge, the heat is Since the heat is emitted outside the plate 12, the bus bar 13 is prevented from overheating.

4(A) is a front view showing the vehicle battery 10, and FIG. 4(B) is an enlarged cross-sectional view of the vehicle battery 10 taken along the line AA shown in FIG. 4(A).

Referring to FIG. 4A, a stud bolt 21 is inserted into a through-hole penetrating substantially the central portion of bus bar 13 . The stud bolt 21 also penetrates a connection bus bar 28 placed on the upper surface of the bus bar 13 . The connection bus bar 28 is connection means for connecting the vehicle batteries 10 to each other. Stud bolt 21 is screwed into nut 27 . With such a configuration, the bus bar 13 and the connection bus bar 28 are fastened and electrically connected. By connecting the connection bus bar 28 via the stud bolt 21 at the central portion of the bus bar 13, the connection distance of the connection bus bar 28 can be shortened.

A bind bar 23 is arranged outside the end plate 12 in the left-right direction. The bind bar 23 is a plate-like member for sandwiching and bundling the stacked battery cells 11 between the end plates 12 . The end plate 12 and the bind bar 23 are fastened with fixing bolts 24 . Furthermore, a module fixing bracket 25 is fixed to the lower portion of the end plate 12 for fixing the vehicle battery 10 to a battery pack housing (not shown).

Referring to FIG. 4B, groove 18 is formed by recessing the inner portion of the upper surface of holder 16 . When the holder 16 is viewed from above, the groove 18 is formed in a frame shape. A wall-like portion 17 is formed by projecting the outermost peripheral portion of the holder 16 upward in a wall-like shape. Note that the nut 27 and the connection bus bar 28 shown in FIG. 4A are not shown here.

Sheet 15 is arranged between heat transfer plate 14 and bus bar 13 . In addition, the lower surface of the sheet 15 covers not only the upper surface of the heat transfer plate 14 but also the upper surface of the holder 16 inside the groove 18 . Moreover, the sheet 15 is made of a flexible material such as a resin having excellent waterproofness. Therefore, the sheet 15 is deformed following the shape of the upper surfaces of the heat transfer plate 14 and the holder 16 . Furthermore, the lower surface of the sheet 15 is adhered to the upper surface of the heat transfer plate 14 and the upper surface of the holder 16 via an adhesive or the like.

On the upper surface of the end plate 12, the heat transfer plate 14 is surrounded by the holder 16, and there is a slight gap between the heat transfer plate 14 and the holder 16. As shown in FIG. The sheet 15 closes this gap from above. Therefore, the condensed water formed on the surface of the bus bar 13 during use is guided along the upper surface of the sheet 15 to the groove 18 of the holder 16 . The condensed water accumulates in the grooves 18 of the holder 16 and then evaporates. Therefore, it is possible to prevent the condensed water from entering between the heat transfer plate 14 and the holder 16 .

According to the vehicle-mounted battery 10 of the present embodiment, overheating of the busbar 13 and its peripheral members can be prevented. Specifically, when the vehicle battery 10 is charged and discharged, a large amount of current passes through the busbar 13, so that the busbar 13 and its peripheral portion where the interface between the different materials exists heats up. In this embodiment, the busbars 13 are thermally coupled to the end plates 12 via the heat transfer plates 14 . Moreover, since the end plate 12 is a plate-like member arranged at the end of the vehicle battery 10, it has a sufficient surface area. Therefore, the heat generated by energizing the bus bar 13 is conducted to the end plate 12 via the heat transfer plate 14 and then released to the outside atmosphere. Therefore, the bus bar 13 is prevented from being heated during charging and discharging, and furthermore, performance deterioration and life deterioration due to overheating of the battery cell 11 are prevented.

Further, referring to FIG. 4A, the entire lower surface of the portion of bus bar 13 extending along the left-right direction is in contact with the upper surface of heat transfer plate 14 . With this configuration, the contact area between the busbars 13 and the end plates 12 via the heat transfer plates 14 can be increased, and the heat dissipation of the busbars 13 can be improved.

Furthermore, in this embodiment, the holder 16 is arranged above the end plate 12 so as to surround the heat transfer plate 14 , and the gap between the heat transfer plate 14 and the holder 16 is covered with the sheet 15 . With such a configuration, the condensed water adhering to the surface of the bus bar 13 runs along the upper surface of the sheet 15 and accumulates in the groove 18 of the holder 16 . Therefore, since dew condensation water does not enter the gap between the heat transfer plate 14 and the holder 16, it is possible to prevent the heat transfer plate 14 and the end plate 12 from being inadvertently electrically connected.

Another form of vehicle battery 10 will be described with reference to FIG. 5 and subsequent drawings.

FIG. 5 is an enlarged cross-sectional view showing vehicle battery 10 according to another embodiment. Here, the wall-like portion 17 of the holder 16 is formed higher than the vehicle-mounted battery 10 shown in FIG. 4 and the like. Specifically, the upper ends of the wall-like portions 17 are arranged above the upper ends of the battery cells 11 . By doing so, a large amount of condensed water can be stored inside the holder 16, and the effect of preventing the condensed water from entering the battery cell 11 side can be remarkably achieved.

FIG. 6 is an enlarged cross-sectional view of vehicle battery 10 according to still another embodiment. In the following description, the grooves 18 arranged forward are referred to as grooves 181 , and the grooves 18 arranged rearward are referred to as grooves 182 . Also, the groove 181 has a bottom surface 191 and the groove 182 has a bottom surface 192 .

Here, a height difference is formed between the bottom surface 191 and the bottom surface 192 . Specifically, the bottom surface 191 of the groove 181 arranged in front is arranged below the bottom surface 192 of the groove 182 arranged in the rear. A height difference L1 between the bottom surface 191 and the bottom surface 192 is, for example, 1 mm.

With such a configuration, the condensed water generated on the surface of the bus bar 13 flows toward the holder 16 . Specifically, the condensed water that has flowed into groove 181 from bus bar 13 stays in groove 181 . Further, since the bottom surface 191 is lower than the bottom surface 192 , the condensed water that has flowed into the grooves 182 from the busbar 13 moves to the grooves 181 . This allows the condensed water to flow away from the battery cell 11 and prevent the condensed water from contacting the battery cell 11 .

FIG. 7 is an enlarged cross-sectional view of vehicle battery 10 according to yet another embodiment. Here, the bottom surface 191 and the bottom surface 192 present an inclined surface that slopes downward toward the front. The angle θ1 at which the bottom surface 191 and the bottom surface 192 are inclined from the horizontal plane is, for example, about 2 degrees. Also, the bottom surface 191 and the bottom surface 192 are arranged on the same plane.

With such a configuration, the condensed water generated on the surface of the bus bar 13 flows forward inside the holder 16 . Specifically, the condensed water that has flowed into groove 181 from bus bar 13 stays in groove 181 . Further, since the bottom surfaces 191 and 192 are inclined surfaces, the condensed water flowing into the grooves 182 from the busbar 13 moves to the grooves 181 . This allows the condensed water to flow away from the battery cell 11 and prevent the condensed water from contacting the battery cell 11 .

FIG. 8 is an enlarged cross-sectional view of vehicle battery 10 according to yet another embodiment. Here, the upper surface of the end plate 12 presents an inclined surface that slopes downward toward the front. Further, the bottom surface 191 and the bottom surface 192 of the holder 16 are also inclined downward toward the front. The angle θ2 at which the top surface, bottom surface 191 and bottom surface 192 of the end plate 12 are inclined from the horizontal plane is, for example, about 5 degrees.

With such a configuration, the condensed water generated on the surface of the bus bar 13 flows forward inside the holder 16 . Specifically, the condensed water that has flowed into groove 181 from bus bar 13 stays in groove 181 . Further, since the bottom surfaces 191 and 192 are inclined surfaces, the condensed water flowing into the grooves 182 from the busbar 13 moves to the grooves 181 . This allows the condensed water to flow away from the battery cell 11 and prevent the condensed water from contacting the battery cell 11 .

Although the embodiments of the present invention have been described above, the present invention is not limited to these, and modifications can be made without departing from the gist of the present invention. In addition, each form described above can be combined with each other.

10 Vehicle battery 11 Battery cell 12 End plate 13 Bus bar 14 Heat transfer plate 15 Sheet 16 Holder 17 Wall-like parts 18, 181, 182 Grooves 191, 192 Bottom surface 20 Fin structure 21 Stud bolt 22 Cell bus bar 23 Bind bar 24 Fixing bolt 25 Module Fixed bracket 26 Opening 27 Nut 28 Connection bus bar 30 Vehicle 31 Vehicle body 32 Battery placement area 33 Bottom

Claims (7)

a plurality of battery cells having external connection terminals;
an end plate made of a good heat conductor disposed on the end side in the direction in which the battery cells are aligned;
a bus bar having one end electrically connected to the external connection terminal and the other end arranged above the end plate;
a heat transfer plate disposed between the end plates and the busbars for passing heat conducted from the busbars to the end plates;
a sheet disposed between the busbar and the heat transfer plate;
a holder that is a frame-shaped member that surrounds the heat transfer plate;
An in-vehicle battery, wherein a gap between the heat transfer plate and the holder is covered with the sheet. 2. The vehicle-mounted battery according to claim 1, further comprising a wall-shaped portion formed on an outer peripheral portion of said holder. 3. The vehicle-mounted battery according to claim 1, wherein a groove is formed in the upper surface of the holder so as to surround the bus bar. 4. The vehicle-mounted battery according to claim 3, wherein a height difference is formed in the groove. 4. The vehicle-mounted battery according to claim 3, wherein the bottom surface of the groove is an inclined surface. 6. The vehicle-mounted battery according to claim 1, wherein the end plate is formed with a fin structure. 7. The vehicle battery according to any one of claims 1 to 6, wherein the upper surface of the end plate is inclined downward toward the outside.

Images