JP7078757B2 - Battery pack - Google Patents

Description

The present disclosure relates to battery packs.

Inventions relating to battery modules for vehicles have been conventionally known (see Patent Document 1 below). An object of the invention described in Patent Document 1 is to dissipate heat in the entire shield case and in the junction box when the junction box is housed in the shield case containing the battery pack. In order to solve this problem, Patent Document 1 discloses a battery module having the following configuration (see the same document, claim 1, paragraph 0009, etc.).

In the conventional battery module, a junction box is housed inside a metal shield case that houses a battery pack, and a resin case of the junction box is mounted on the bottom wall of the shield case. Further, a fan is attached to the wall of the shield case, and an exhaust port for discharging the air circulating inside the shield case is provided. In addition, a vent is provided in the case of the junction box so that a part of the air flowing into the shield case is circulated in the case of the junction box.

Further, in the conventional battery module, the relay is arranged so as to be exposed on the upper surface of the case of the junction box (see the same document, claim 2, paragraph 0010, etc.). With such a configuration, it is possible to simultaneously cool the inside of the junction box housed in the shield case with the air that cools the inside of the shield case, and the heat of the junction box case is conducted to the metal shield case. Heat dissipation can be achieved (see the same document, paragraph 0011, etc.).

In the above-mentioned conventional battery module, the junction box is mounted by exposing the relay on the surface of a case made of a resin molded product. More specifically, the case has a lower case having front, rear, left and right side walls with a lower opening, and a relay consisting of an upper case locked to the upper part of the lower case is mounted on the upper surface of the upper case (the same document, No. 1). See paragraph 0015, FIGS. 1, 2, etc.).

Alternatively, in the conventional battery module, the high voltage relay is directly fixed on a metal plate laid on the bottom wall of the shield case of the battery module. With this configuration, the heat generated in the high voltage relay can be directly conducted to the bottom wall of the shield case via the metal plate and radiated (see the same document, paragraphs 0021 and 0022, FIG. 3 and the like).

Japanese Unexamined Patent Publication No. 2013-090484

In the above-mentioned conventional battery module, when the relay is arranged on the upper surface of the upper case made of a resin molded product as described above, the amount of heat conducted and dissipated to the bottom wall of the shield case via the upper case and the lower case is Very few. Therefore, it is necessary to provide a fan and an exhaust port on the wall of the shield case, provide a ventilation port on the case of the junction box, and air-cool the relay. Such a battery module has a complicated configuration and is difficult to miniaturize.

On the other hand, in the configuration in which the high-voltage relay is directly fixed on the metal plate laid on the bottom wall of the shield case of the battery module, the metal plate conducts the heat generated in the high-voltage relay to the bottom wall of the shield case and dissipates the heat. However, since the heat conduction path of this metal plate connects the high-voltage relay and the bottom wall of the shield case at the shortest distance, the heat generated in the high-voltage relay causes the bottom wall of the shield case to become locally hot. There is a risk of becoming.

The present disclosure provides a battery pack capable of dissipating heat generated in a relay to a housing by heat conduction and suppressing the temperature of the housing from becoming locally high.

One aspect of the present disclosure is a battery pack comprising a housing, a plurality of battery cells housed in the housing, and relays connected to the plurality of battery cells, which are generated in the relay. A battery pack comprising a heat-dissipating member that conducts heat and dissipates heat, wherein the heat-dissipating member forms a heat-conducting path longer than the shortest distance between the relay and the housing.

According to the above aspect of the present disclosure, the heat dissipation member can form a heat conduction path between the relay and the housing, which is longer than the shortest distance between the relay and the housing. Therefore, the present invention provides a battery pack capable of radiating the heat generated in the relay to the housing by heat conduction through the heat conduction path and suppressing the temperature of the housing locally becoming high. be able to.

The perspective view of the battery pack which concerns on embodiment of this disclosure. FIG. 3 is a perspective view showing a state in which the cover of the battery pack housing shown in FIG. 1 is removed. An exploded perspective view of a battery module housed in a battery pack housing shown in FIG. 1. FIG. 3 is a perspective view of an electrical component holder housed in a battery pack housing shown in FIG. 1. The perspective view which shows the positional relationship between the heat radiation member of the battery pack shown in FIG. 2 and a relay. An enlarged cross-sectional view taken along the VI-VI line shown in FIG. The perspective view which concerns on the modification 1 of the battery pack shown in FIG. The perspective view which concerns on the modification 2 of the battery pack shown in FIG. Enlarged sectional view taken along line IX-IX in FIG. The perspective view which concerns on the modification 3 of the battery pack shown in FIG. The perspective view which concerns on the modification 4 of the battery pack shown in FIG.

Hereinafter, embodiments of the battery pack according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a perspective view of the battery pack 100 according to the present embodiment. FIG. 2 is a perspective view showing a state in which the cover 12 of the housing 10 of the battery pack 100 shown in FIG. 1 is removed. FIG. 3 is an exploded perspective view of the battery module 20 housed in the housing 10 of the battery pack 100 shown in FIG. FIG. 4 is a perspective view of the electrical component holder 30 housed in the housing 10 of the battery pack 100 shown in FIG. The battery pack 100 shown in FIG. 2 is in a state in which not only the cover 12 but also accessories including the electrical component holder 30 shown in FIG. 4 are removed.

Although the details will be described later, the battery pack 100 of the present embodiment has the following main features. The battery pack 100 includes a housing 10, a plurality of battery cells 1 housed in the housing 10, and a relay 32 connected to the plurality of battery cells 1. Further, the battery pack 100 includes a heat radiating member 40 that conducts heat generated in the relay 32 and dissipates heat. The heat radiating member 40 forms a heat conduction path Pt longer than the shortest distance Ds between the relay 32 and the housing 10 (see FIG. 6).

Hereinafter, the configuration of each part of the battery pack 100 of the present embodiment will be described in detail. The battery pack 100 of the present embodiment includes, for example, a housing 10, a battery module 20, an electrical component holder 30, and a heat radiating member 40.

The housing 10 has, for example, a substantially rectangular parallelepiped shape, and is a box shape having a vertical dimension larger than a horizontal dimension and a height dimension. In the following, a battery is used using an orthogonal coordinate system consisting of an X-axis parallel to the horizontal direction of the housing 10, a Y-axis parallel to the vertical direction of the housing 10, and a Z-axis parallel to the height direction of the housing 10. Each part of the pack 100 may be described.

The housing 10 has, for example, a rectangular box-shaped main body portion 11 having an open upper portion and a lid-shaped cover 12 that closes an opening at the upper portion of the main body portion 11. The material of the main body 11 is, for example, a metal material such as an electrozinc-plated steel plate, and the material of the cover 12 is a resin material such as polybutylene terephthalate (PBT).

The main body 11 shown in FIG. 2 accommodates the battery module 20 on one side (−X direction side) in the lateral direction, and accommodates the electrical component holder 30 shown in FIG. 4 in the space on the other side (+ X direction side) in the lateral direction. Then, the heat radiating member 40 is housed between the battery module 20 and the electrical component holder 30.

In the cover 12 shown in FIG. 1, for example, recesses are formed at the corners of both ends in the vertical direction (Y direction) at the ends on one side (+ X direction side) in the horizontal direction, and openings are formed in the recesses. .. The battery pack 100 exposes a pair of high-voltage terminals 101, which are external terminals, to the opening of the cover 12. The battery pack 100 is supplied with electric power from an external device via the high voltage terminal 101, and supplies electric power to the external device via the high voltage terminal 101.

Further, the cover 12 has, for example, a recess in the vertical direction inside (-Y direction side) of the corner portion on one side in the horizontal direction (+ X direction side) and one side in the vertical direction (+ Y direction side) in which the high voltage terminal 101 is arranged. An opening is formed in this recess to expose the signal connector 102. The battery pack 100 exposes the signal connector 102 to the opening of the cover 12. The battery pack 100 is connected to, for example, an electronic control unit mounted on a vehicle via a signal connector 102. The signal connector 102 is, for example, a connector for a control signal of the battery pack 100, and inputs / outputs information and receives electric power.

As shown in FIG. 2, for example, the battery module 20 is housed on one side in the lateral direction (-X direction side) inside the housing 10, and is fixed to the housing 10 by a fastening member such as a bolt. As shown in FIG. 3, for example, the battery module 20 holds a plurality of flat square battery cells 1 and each battery cell 1 from both sides in the thickness direction (Z direction) to thicken the plurality of battery cells 1. It is provided with a plurality of cell holders 22 to be laminated in the longitudinal direction (Z direction).

Further, the battery module 20 includes a bus bar 21 (see FIG. 2) for connecting a plurality of battery cells 1 and a pair of end plates 23 arranged at both ends of the plurality of battery cells 1 in the stacking direction via a cell holder 22. A plurality of connecting portions 24 for connecting the pair of end plates 23 are provided. Further, the battery module 20 includes a bus bar case 25 (see FIG. 2) arranged to face the battery lid 1d along the thickness direction (Z direction) of the plurality of battery cells 1.

The plurality of battery cells 1 have a substantially rectangular parallelepiped flat rectangular shape, are laminated in the thickness direction (Z direction), and are housed in the housing 10. The battery cell 1 is, for example, a square lithium ion secondary battery. The battery cell 1 includes a flat square battery can 1c, a battery lid 1d that closes an opening of the battery can 1c, an electrode group and an electrolytic solution housed in the battery can 1c (not shown), and an electrode group thereof. It includes a pair of external terminals 1g that are connected and attached to the battery lid 1d.

The battery can 1c is a flat bottomed square cylindrical container having an opening at one end, and the bottom portion is covered with an insulating film 1f. The insulating film 1f is a resin film having electrical insulating properties, and for example, electrically insulates between the housing 10 and the battery cell 1. The battery lid 1d is, for example, a substantially rectangular plate-shaped member, and the battery can 1c is sealed by being joined to the opening of the battery can 1c by laser welding over the entire circumference.

The battery can 1c and the battery lid 1d form a battery container that houses and seals the electrode group and the electrolytic solution. The battery lid 1d has, for example, a safety valve 1v that cleaves and releases the gas inside the battery cell 1 when the internal pressure of the battery cell 1 rises above a predetermined pressure. The electrode group is, for example, a wound electrode group in which a long strip-shaped positive electrode and a long strip-shaped negative electrode are wound so as to face each other via a separator which is a long strip-shaped insulating member.

The positive electrode constituting the electrode group is connected to the external terminal 1g of the positive electrode, for example, via the current collector plate of the positive electrode. The negative electrodes constituting the electrode group are connected to the external terminal 1g of the negative electrode, for example, via the current collector plate of the negative electrode. The electrolytic solution is contained in the battery can 1c by being injected into the battery can 1c from, for example, a liquid injection port provided in the battery lid 1d, and is impregnated into the electrode group. In the battery cell 1, the battery can 1c is sealed by the battery lid 1d by joining the injection plug 1k to the injection port of the battery lid 1d by, for example, laser welding after injecting the electrolytic solution.

The two battery cells 1 adjacent to each other in the stacking direction (Z direction), which is the thickness direction of the battery cells 1, are alternately inverted by 180 [°] so that the external terminals 1g having different polarities are adjacent to each other in the stacking direction. Has been done. Then, by connecting the external terminals 1g having different polarities of the adjacent battery cells 1 sequentially in the stacking direction by the bus bar 21 (see FIG. 2), the plurality of stacked battery cells 1 are connected in series. be able to.

The bus bar 21 is, for example, a plate-shaped member made of a conductive metal such as aluminum or copper, which is bonded to the external terminal 1g of the battery cell 1 by laser welding or ultrasonic bonding, and is external to the adjacent battery cell 1. It is electrically connected between the terminals 1g. As shown in FIG. 3, for example, the battery module 20 has two rows of battery rows composed of a plurality of flat square battery cells 1 stacked in the height direction (Z direction) of the battery pack 100. The two rows of batteries in which the battery cells 1 are laminated in the thickness direction (Z direction) are arranged in the width direction (Y direction) of the battery cells 1.

The cell holder 22 is configured to hold the battery cells 1 from both sides in the thickness direction (Z direction) and stack the plurality of battery cells 1 in the thickness direction. The cell holder 22 is made of an engineering plastic having electrical insulation such as polybutylene terephthalate (PBT), is interposed between the battery cell 1 and the battery cell 1, and is interposed between the battery cell 1 and the battery cell 1. It functions as an insulating separator or a spacer that provides a space between the battery cell 1 and the battery cell 1.

The pair of end plates 23 are plate-shaped members arranged on both sides of the plurality of battery cells 1 in the stacking direction, and sandwich the plurality of battery cells 1 from both sides in the stacking direction via the cell holder 22. The pair of end plates 23 are fixed to the plurality of connecting portions 24 by fastening members such as bolts in a state where a compressive force is applied in the stacking direction of the plurality of battery cells 1, for example. Although the details will be described later, these plurality of connecting portions 24 form, for example, a second path Pt2 (see FIG. 5) which is a part of the heat conduction path Pt for conducting the heat generated in the relay 32 to the housing 10. ..

The connecting portion 24 is, for example, a plate-shaped or block-shaped metal member, and is arranged so as to face both side surfaces of the plurality of battery cells 1 facing the width direction (Y direction). More specifically, the battery module 20 is located between a pair of connecting portions 24 as side plates arranged so as to sandwich two rows of battery rows from both sides in the width direction of the battery cells 1 and between the two rows of battery rows. It has a connecting portion 24 as an arranged center plate.

Each connecting portion 24 has, for example, a convex portion protruding in the height direction (+ X direction) of the battery cell 1. This convex portion is fixed to the heat radiating member 40 shown in FIG. 2 via a fastening member such as a bolt. As a result, the heat radiating member 40 and the connecting portion 24 are in contact with each other, and are electrically conductively connected between them. Further, the connecting portion 24, which is a pair of side plates facing the side walls 10c at both ends in the vertical direction of the housing 10, is fixed to the housing 10 via a fastening member such as a bolt. As a result, the connecting portion 24 and the housing 10 are brought into contact with each other, and are thermally conductively connected between them.

The bus bar case 25 is arranged so as to engage with, for example, a protrusion-shaped engaging portion provided on the cell holder 22 and cover an end surface provided with external terminals 1g of a plurality of battery cells 1. The bus bar case 25 is, for example, a rectangular frame-shaped member made of engineering plastic such as PBT similar to the cell holder 22, and has a plurality of openings for exposing the external terminal 1 g of the battery cell 1. Further, the bus bar case 25 is insulated from each other by a partition wall, for example, between the bus bars 21 adjacent to each other.

As shown in FIG. 4, the electrical component holder 30 holds, for example, a control board 31, a relay 32, a fuse 33, a shunt resistor 34, and a pair of connection terminals 35. The control board 31 is fixed to, for example, the surface of the electrical component holder 30 facing the battery module 20 with bolts. The shunt resistor 34 is fixed to the control board 31 by a screw, for example, and is arranged in the current path between the connection terminal 35 of the negative electrode and the high voltage terminal 101 of the negative electrode.

The control board 31 is connected to, for example, each bus bar 21 connecting the battery cells 1 adjacent to each other in the stacking direction via a voltage detection line. The control board 31 includes, for example, a control circuit that measures and monitors the voltage of each battery cell 1 and controls and monitors the entire battery pack 100. The relay 32 and the fuse 33 are fixed to the electrical component holder 30 by, for example, a screw, and are arranged in the current path between the connection terminal 35 of the positive electrode and the high voltage terminal 101 of the positive electrode.

The relay 32 cuts off and connects, for example, the current path between one of the high voltage terminals 101 and the end bus bar of the battery module 20. In the present embodiment, the relay 32 is, for example, a mechanical relay, which is composed of a coil and a switch, and can be switched on and off by turning on or off the current flowing through the coil. .. By turning on the switch of the relay 32, the current path between the high voltage terminal 101 and the battery module 20 is connected, and by turning off the switch of the relay 32, the electric path is cut off.

The relay 32 has a case 32a for accommodating electronic components including coils and switches. The case 32a is, for example, a rectangular box-shaped container having a substantially rectangular parallelepiped shape. The case 32a can be made of an electrically insulating resin material such as PBT. The shortest distance Ds (see FIG. 6) between the relay 32 and the housing 10 described later is, for example, the shortest distance Ds between the case 32a of the relay 32 and the housing 10.

Of the pair of connection terminals 35 shown in FIG. 4, the positive electrode connection terminal 35 arranged on the left side (+ Y direction) is an external terminal 1g of the positive electrode of the battery cell 1 at one end of a plurality of battery cells 1 connected in series. Is connected via the end bus bar. Of the pair of connection terminals 35, the negative electrode connection terminal 35 arranged on the right side (-Y direction) is connected to the external terminal 1g of the negative electrode of the battery cell 1 at the other end of the plurality of battery cells 1 connected in series. Connected via an end bus bar.

That is, in the battery pack 100 shown in FIG. 1, the high voltage terminal 101 on the right side (+ Y direction) is, for example, an external terminal of a positive electrode connected to the positive electrode side of a plurality of battery cells 1. Further, the high voltage terminal 101 on the left side (-Y direction) is, for example, an external terminal of a negative electrode connected to the negative electrode side of a plurality of battery cells 1.

The heat radiating member 40 is a member for conducting heat generated in the relay 32 to dissipate heat. As the material of the heat radiating member 40, for example, a metal such as stainless steel, an aluminum alloy, a copper alloy, a carbon steel, or an alloy steel, or a non-metal such as a high thermal conductive ceramic or a high thermal conductive resin material can be used. The surface of the heat radiating member 40 may have irregularities except for the portion in contact with the relay 32.

From the viewpoint of efficiently conducting heat generated in the relay 32 to dissipate heat, the thermal conductivity of the material of the heat radiating member 40 is preferably higher than the thermal conductivity of the material of the case 32a of the relay 32. Further, from the viewpoint of increasing the heat capacity of the heat radiating member 40 and promoting heat dissipation of the relay 32, the volume of the heat radiating member 40 is preferably larger than the volume of the relay 32.

The shape of the heat radiating member 40 is not particularly limited as long as it can efficiently conduct heat generated in the relay 32 and dissipate heat. It can be in the shape of a columnar or elongated plate extending in the Y direction). The heat radiating member 40 has, for example, a relay 32 arranged and has a heat transfer surface 40a along the vertical direction (Y direction) and the height direction (Z direction) of the housing 10. The heat radiating member 40 extends from one end to the other end of the battery module 20 including the plurality of battery cells 1, and the surface opposite to the heat transfer surface 40a faces the plurality of battery cells 1.

FIG. 5 is a perspective view showing a positional relationship between a relay 32 held in the electrical component holder 30 shown in FIG. 4 and a heat radiating member 40 that transfers heat generated in the relay 32 and dissipates heat. FIG. 6 is an enlarged cross-sectional view taken along the line VI-VI shown in FIG. In FIGS. 5 and 6, the cover 12 of the housing 10, the plurality of battery cells 1 of the battery module 20, the bus bar 21, the cell holder 22, the bus bar case 25, the electrical component holder 30, and the electrical component holder 30 The illustration of parts other than the held relay 32 is omitted.

The heat radiating member 40 is a member that conducts heat generated in the relay 32 to radiate heat. The relay 32 is arranged, for example, on the heat transfer surface 40a of the heat radiation member 40 which is substantially parallel in the vertical direction (Y direction) and the height direction (Z direction) of the housing 10. The heat transfer surface 40a may be in direct contact with the case 32a of the relay 32, or may be indirectly in contact with the case 32a of the relay 32 via a heat dissipation adhesive, thermal paste, heat dissipation sheet, heat conduction sheet, or the like. You may. In this way, the heat transfer surface 40a is in direct or indirect contact with the relay 32, so that heat can be dissipated from the relay 32 to the heat transfer surface 40a by heat conduction.

As shown in FIG. 6, the heat radiating member 40 forms a heat conduction path Pt longer than the shortest distance Ds between the relay 32 and the housing 10. More specifically, in the example shown in FIG. 6, the shortest distance Ds between the relay 32 and the housing 10 is the surface of the case 32a of the relay 32 opposite to the heat transfer surface 40a of the heat dissipation member 40 and the housing. The distance between the inner surface of the side wall 10c of the body 10 and the inner surface.

Further, in the example shown in FIG. 6, the bottom surface 40b of the heat radiating member 40 is in contact with the bottom wall 10b of the housing 10. In this case, the heat conduction path Pt passes through the inside of the heat radiation member 40 and passes through the surface 32b of the relay 32 facing the heat transfer surface 40a of the heat radiation member 40, that is, the surface 32b of the case 32a and the bottom wall 10b of the housing 10. It contains a myriad of connecting routes.

The shortest heat conduction path Pt among the innumerable paths passes from the lower end of the surface 32b of the relay 32, passes through the heat transfer surface 40a of the heat radiation member 40, and reaches the bottom wall 10b of the housing 10 along the heat transfer surface 40a. It is a path facing the bottom wall 10b of the housing 10 through the bottom surface 40b of the heat radiating member 40. This shortest heat conduction path Pt is longer than the shortest distance Ds between the relay 32 and the housing 10.

Further, in the example shown in FIG. 6, the distance D between the bottom surface 32c of the relay 32 facing the bottom wall 10b of the housing 10 and the bottom wall 10b of the housing 10 is between the relay 32 and the housing 10. Is assumed to be the shortest distance. Also in this case, the shortest heat conduction path Pt is longer than the distance D between the bottom surface 32c of the relay 32 and the bottom wall 10b of the housing 10. This is because the heat transfer surface 40a of the heat radiation member 40 is substantially parallel to the height direction (Z direction) of the housing 10, and the shortest heat conduction path Pt is directed from the surface 32b of the relay 32 to the heat transfer surface 40a. This is because it includes a path in the lateral direction (X direction) of the housing 10.

Further, in the examples shown in FIGS. 5 and 6, at least a part of the bottom surface 40b of the heat radiating member 40 and the bottom wall 10b of the housing 10 are in direct contact with each other, but the heat radiating adhesive, the heat radiating grease, and the heat radiating sheet are in direct contact with each other. , Or may be indirectly contacted via a heat conductive sheet or the like.

Further, in the height direction (Z direction) of the housing 10, the heat radiating member 40 may have a gap G (see FIG. 9) with the bottom wall 10b of the housing 10. In this case, both ends of the heat radiating member 40 can be fixed to the side walls 10c on both sides of the housing 10 in the vertical direction (Y direction) of the housing 10. As a result, the heat radiating member 40 extending in the vertical direction (Y direction) of the housing 10 forms a heat conduction path Pt longer than the shortest distance Ds between the relay 32 and the housing 10.

Further, in the examples shown in FIGS. 5 and 6, in the battery pack 100, the heat radiating member 40 has a protrusion 41 as a fixing member for fixing the heat radiating member 40 to the housing 10. The protrusion 41 has, for example, a bolt hole through which a bolt is inserted, and is fastened to the bottom wall 10b of the housing 10 by bolts and nuts to fix the heat radiating member 40 to the bottom wall 10b of the housing 10.

The heat radiating member 40 may have a gap G in contact with the bottom wall 10b of the housing 10 at the protrusion 41 and between the heat radiating member 40 and the housing 10 at other portions. In this case, the heat conduction path Pt is formed by the first path Pt1 formed by the heat dissipation member 40 and conducting the heat generated in the relay 32 to the protrusion 41 which is a fixing member, and the protrusion 41 which is a fixing member. It has a second path Pt2 that conducts heat of the heat radiating member 40 to the housing 10.

Further, in the examples shown in FIGS. 5 and 6, the battery pack 100 includes a connecting portion 24 of the battery module 20 as a fixing member for fixing the heat radiating member 40 to the housing 10. As shown in FIG. 3, the pair of connecting portions 24 on both sides of the housing 10 in the vertical direction (Y direction) have screw holes on the surface of the housing 10 facing the side wall 10c, and the housing 10 is provided with bolts. It is fastened to the side wall 10c. Further, the connecting portion 24 has a screw hole on the tip surface of the convex portion protruding toward the heat radiating member 40.

Therefore, the connecting portion 24 is fixed to the side wall 10c of the housing 10, and the heat radiating member 40 is attached to the housing 10 by fastening a bolt inserted into the bolt hole of the heat radiating member 40 to the screw hole at the tip of the convex portion. It is a fixing member to be fixed. In this case, the heat conduction path Pt is formed by the first path Pt1 formed by the heat radiating member 40 and conducting the heat generated in the relay 32 to the connecting portion 24 which is a fixing member, and the connecting portion 24 which is a fixing member. It has a second path Pt2 for conducting heat of the heat radiating member 40 to the housing 10.

Hereinafter, the operation of the battery pack 100 of the present embodiment will be described.

The battery pack 100 of the present embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, a signal connector 102 is connected to a vehicle-side controller, and information is exchanged and power is supplied via the signal connector 102. The battery pack 100 stores the electric power supplied to the high voltage terminals 101 and 101 in the battery cell 1, and supplies the electric power stored in the battery cell 1 to the outside via the high voltage terminals 101 and 101. At this time, the switch of the relay 32 is turned on, and a high voltage current flows through the relay 32, so that heat is generated in the relay 32.

Here, as described above, the battery pack 100 of the present embodiment includes a housing 10, a plurality of battery cells 1 housed in the housing 10, and a relay 32 connected to the plurality of battery cells 1. , Is equipped. Further, the battery pack 100 includes a heat radiating member 40 that conducts heat generated in the relay 32 and dissipates heat. The heat radiating member 40 forms a heat conduction path Pt longer than the shortest distance Ds between the relay 32 and the housing 10.

With this configuration, the heat generated in the relay 32 can be radiated to the housing 10 by heat conduction through the heat radiating member 40. Further, the heat radiating member 40 forms a heat conduction path Pt longer than the shortest distance Ds between the relay 32 and the housing 10, so that the heat conduction path Pt is between the relay 32 and the housing 10 as in the conventional case. It is possible to suppress the temperature of the housing 10 from becoming locally high as compared with the case where the housing 10 is formed at the shortest distance Ds.

Further, in the battery pack 100 of the present embodiment, the housing 10 has a box shape in which the dimensions in the vertical direction (Y direction) are larger than the dimensions in the horizontal direction (X direction) and the height direction (Z direction). The heat radiating member 40 has a relay 32 arranged and has a heat transfer surface 40a along the vertical direction (Y direction) and the height direction (Z direction).

With this configuration, the shortest heat conduction path Pt from the relay 32 to the housing 10 includes a lateral (X direction) path of the housing 10 from the surface 32b of the relay 32 to the heat transfer surface 40a. As a result, when the distance D between the bottom surface 32c of the relay 32 facing the bottom wall 10b of the housing 10 and the bottom wall 10b of the housing 10 is the shortest distance between the relay 32 and the housing 10. However, the heat conduction path Pt can be made longer than the shortest distance. As a result, it is possible to suppress the temperature of the housing 10 from becoming locally high as compared with the case where the heat conduction path Pt is formed at the shortest distance Ds between the relay 32 and the housing 10 as in the conventional case. Can be done.

Further, in the battery pack 100 of the present embodiment, the heat radiating member 40 extends from one end to the other end of the plurality of battery cells 1. With this configuration, when a strong force acts in the vertical direction (Y direction) of the housing 10, that is, in the extending direction of the heat radiating member 40 due to an unexpected situation such as a vehicle collision, the heat radiating member 40 causes a plurality of battery cells. 1 can be protected. That is, the heat radiating member 40 extending from one end to the other end of the plurality of battery cells 1 can suppress the deformation of the housing 10 and suppress the damage of the plurality of battery cells 1. The relay 32 may be arranged on the surface of the heat radiating member 40 facing the plurality of battery cells 1. As a result, the heat radiating member 40 can prevent the relay 32 from being subjected to an external force to protect the relay 32.

Further, by extending the heat radiating member 40 from one end to the other end of the plurality of battery cells 1, the volume of the heat radiating member 40 can be increased, and the heat capacity of the heat radiating member 40 can be increased. Further, when a gap G is provided between the bottom surface 40b of the heat radiating member 40 and the bottom wall 10b of the housing 10, the length of the heat conduction path Pt in the vertical direction (Y direction) of the housing 10 is increased. Can be done. As a result, it is possible to more reliably suppress the temperature of the housing 10 from becoming locally high.

Further, in the battery pack 100 of the present embodiment, as described above, both ends of the heat radiating member 40 may be fixed to the side walls 10c on both sides of the housing 10 in the vertical direction (Y direction) of the housing 10. In this case, a gap G may be provided between the heat radiating member 40 and the bottom wall 10b of the housing 10 in the height direction (Z direction) of the housing 10.

With this configuration, it is possible to form a path extending in the vertical direction (Y-axis direction) of the housing 10 in a part of the heat conduction path Pt. As a result, for example, even if the shortest distance between the relay 32 and the housing 10 is the height direction (Z-axis direction) of the housing 10, the heat conduction path Pt is between the relay 32 and the housing 10. Can be sufficiently longer than the shortest distance of. Therefore, it is possible to more reliably suppress the temperature of the housing 10 from becoming locally high.

Further, the battery pack 100 of the present embodiment includes fixing members such as a protrusion 41 and a connecting portion 24 for fixing the heat radiating member 40 to the housing. The heat conduction path Pt is a first path Pt1 formed by the heat radiating member 40 to conduct the heat generated in the relay 32 to the fixing member, and the heat conduction path Pt formed by the fixing member to conduct the heat of the heat radiating member 40 to the housing 10. It has a second path Pt2 and the like. With this configuration, it is possible to increase the total heat capacity of the members forming the heat conduction path Pt and more reliably suppress the temperature of the housing 10 from becoming locally high.

Further, the battery pack 100 of the present embodiment has a cell holder 22 that holds each battery cell 1 and stacks a plurality of battery cells 1, and cell holders 22 at both ends of the plurality of battery cells 1 in the stacking direction (Z-axis direction). A pair of end plates 23 arranged via the above and a plurality of connecting portions 24 for connecting the pair of end plates 23 are provided. The fixing member for fixing the heat radiation member 40 to the housing 10 is the connecting portion 24.

With this configuration, the heat radiating member 40 can be fixed to the housing 10 by using the connecting portion 24 of the battery module 20 which is the existing configuration of the battery pack 100. Further, not only the heat radiation member 40 but also the heat conduction path Pt that transfers the heat generated in the relay 32 and dissipates the heat to the housing 10 by using the connecting portion 24 of the battery module 20 which is an existing configuration of the battery pack 100. Can be formed. As a result, it is possible to more reliably suppress the temperature of the housing 10 from becoming locally high without adding extra parts.

Further, in the battery pack 100 of the present embodiment, the volume of the heat radiating member 40 is larger than the volume of the relay 32. With this configuration, the heat capacity of the heat radiating member 40 can be increased, and the heat radiating member 40 can be prevented from becoming hot. Further, the surface area of the heat radiating member 40 can be increased to promote heat dissipation of the heat radiating member 40. Therefore, it is possible to more reliably suppress the temperature of the housing 10 from becoming locally high.

Further, in the battery pack 100 of the present embodiment, the material of the heat radiating member 40 is, for example, metal. With this configuration, for example, the strength of the heat radiating member 40 can be improved as compared with the resin material, and the housing 10 can be reinforced by the heat radiating member 40. Further, since the metal has excellent thermal conductivity, the heat generated in the relay 32 can be efficiently radiated by the metal heat radiating member 40.

As described above, according to the present embodiment, the heat generated in the relay 32 can be dissipated to the housing 10 by heat conduction, and it is possible to suppress the temperature of the housing 10 from becoming locally high. A possible battery pack 100 can be provided.

The battery pack according to the present disclosure is not limited to the configuration of the battery pack 100 described in the above-described embodiment. Hereinafter, some modifications of the above-mentioned battery pack 100 will be described with reference to FIGS. 7 to 11. In each figure, the same components as those of the battery pack 100 described above are designated by the same reference numerals as those of the battery pack 100 described above, and the description thereof will be omitted.

FIG. 7 is a perspective view according to a modification 1 of the battery pack 100 shown in FIG. In this modification, in the plurality of battery cells 1 constituting the battery module 20, as shown in FIG. 3, the battery lid 1d provided with the external terminal 1g is above the height direction (+ Z direction) of the housing 10. It is arranged by rotating it at an angle of 90 degrees so as to face. In this case, the stacking direction of the battery cells 1 is the lateral direction (X direction) of the housing 10. Even with such a configuration, the same effect as that of the battery pack 100 according to the above-described embodiment can be obtained.

FIG. 8 is a perspective view according to a modification 2 of the battery pack 100 shown in FIG. FIG. 9 is an enlarged cross-sectional view taken along the line IX-IX of FIG. The battery pack 100 according to this modification is different from the battery pack 100 according to the above-described embodiment in that the relay 32 is a semiconductor relay. In this modification, the relay 32 is mounted on the substrate 32s, for example, and is in contact with the heat radiating member 40 via the substrate 32s. The substrate 32s may be indirectly in contact with the heat radiating member 40 via the heat radiating adhesive, the heat radiating grease, the heat radiating sheet, or the like.

In this modification, the battery pack 100 includes a plurality of relays 32. In this case, it is preferable that the volume of the heat radiating member 40 is larger than the total volume of the plurality of relays 32. Further, in this modification, the shortest distance Ds between the relay 32 and the housing 10 is the distance between the end face of the relay 32 closest to the housing 10 and the housing 10. Further, in the battery pack 100 of the present modification, a gap G is formed between the bottom surface 40b of the heat radiating member 40 and the bottom wall 10b of the housing 10. Also in this modification, the same effect as that of the battery pack 100 according to the above-described embodiment can be obtained.

10 and 11 are perspective views according to the modified example 3 and the modified example 4 of the battery pack shown in FIG. 5, respectively. In the battery pack 100 according to the modification 3 shown in FIG. 10, the length of the heat radiating member 40 in the vertical direction (Y direction) of the housing 10 is shorter than the length of the battery pack 100 according to the above-described embodiment. With this configuration, not only the same effect as that of the battery pack 100 according to the above-described embodiment can be obtained, but also the weight of the battery pack 100 can be reduced, and a space for accommodating the electrical component holder 30 and accessories can be provided. Can be expanded.

Further, in the battery pack 100 according to the modified example 4 shown in FIG. 11, the heat radiating member 40 is not fixed to the connecting portion 24 of the battery module 20, and the bottom wall 10b of the housing 10 is passed through the flange portion 42 as the fixing member. It is fixed to. With such a configuration, not only the same effect as the battery pack 100 according to the above-described embodiment can be obtained, but also the same effect as the battery pack 100 according to the third modification can be obtained.

Although the embodiment of the battery pack according to the present disclosure has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are made without departing from the gist of the present disclosure. If any, they are included in this disclosure.

1 Battery cell 10 Housing 10b Bottom wall 10c Side wall 22 Cell holder 23 End plate 24 Connecting part (fixing member)
32 Relay 40 Heat transfer member 40a Heat transfer surface 41 Projection (fixing member)
42 Flange part (fixing member)
100 Battery pack Ds Shortest distance G Gap Pt Heat conduction path Pt1 1st path Pt2 2nd path

Claims (6)

A battery pack including a housing, a plurality of battery cells housed in the housing, and a relay connected to the plurality of battery cells.
It is equipped with a heat dissipation member that conducts heat generated in the relay and dissipates it.
The housing has a box shape in which the vertical dimension is larger than the horizontal and height dimensions, and both ends of the heat radiating member are fixed to the side walls on both sides of the housing in the vertical direction. In the vertical direction, there is a gap between the heat dissipation member and the bottom wall of the housing.
The heat dissipation member forms a heat transfer path longer than the shortest distance between the relay and the housing, and has a heat transfer surface along the vertical direction and the height direction in which the relay is arranged. , A battery pack characterized in that it extends from one end to the other end of the plurality of battery cells. A fixing member for fixing the heat radiation member to the housing is provided.
The heat conduction path is a first path formed by the heat radiating member to conduct heat generated in the relay to the fixing member, and a heat conduction path formed by the fixing member to conduct heat of the heat radiating member to the housing. The battery pack according to claim 1, wherein the battery pack has a second path. A cell holder that holds each of the battery cells and stacks a plurality of the battery cells, a pair of end plates arranged at both ends of the plurality of battery cells in the stacking direction via the cell holder, and the pair of end plates. With multiple connecting parts to connect,
The battery pack according to claim 2 , wherein the fixing member is the connecting portion. The battery pack according to claim 1, wherein the volume of the heat radiating member is larger than the volume of the relay. The battery pack according to claim 1, wherein the material of the heat radiating member is metal. The battery pack according to claim 1, wherein the relay is a semiconductor relay.

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