Battery pack and manufacturing method thereof

Discussed is a battery pack having a simplified structure and a method for manufacturing the same. The battery pack includes: an upper case and a lower case; a battery module stack in which battery modules are stacked between the upper case and the lower case; a longitudinal square tube mounted on the battery module stack; a vertical square tube mounted on the battery module stack; and a horizontal square tube mounted on the battery module stack.

CROSS-CITATION WITH RELATED APPLICATION(S)

This application claims the benefit of Korean Patent Application No. 10-2019-0127009 filed on Oct. 14, 2019 with the Korean Intellectual Property Office, the disclosures of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a battery pack and a method for manufacturing the same, and more particularly, to a battery pack having a simplified structure and a method for manufacturing the same.

BACKGROUND ART

A secondary battery has attracted much attention as an energy source in various products such as a mobile device and an electric vehicle. The secondary battery is a potent energy resource that can replace the use of existing products using fossil fuels, and is in the spotlight as an environment-friendly energy source because it does not generate by-products due to energy use.

Recently, along with a continuous rise of the necessity for a large-capacity secondary battery structure, including the utilization of the secondary battery as an energy storage source, there is a growing demand for a battery pack of a multi-module structure which is an assembly of battery modules in which a plurality of secondary batteries are connected in series/parallel.

Meanwhile, when a plurality of battery cells are connected in series/parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell, and to configure a battery pack by using at least one of the battery modules and adding other components.

Such a battery pack includes an upper case and lower case, a battery module stack in which battery modules are stacked between the upper case and the lower case, and a plurality of tubes for fixing the battery modules of the battery module stack.

In conventional indirect water-cooled battery modules, a cooling plate (heat sink) through which liquid refrigerant flows was attached to the lower part of the battery module, and it was usually mounted on the pack tray as only one layer. This is because the battery pack is generally placed low and wide on the floor under the seat space of a passenger car.

Recently, electric drive development has been carried out not only for passenger cars but also for commercial vehicles such as trucks. In the case of a truck like this,

There is a demand to locate the driving battery in the location where the existing fuel tank was placed (specifically, the space under the cargo compartment on the left and right sides behind the front axle). The battery pack mounted on a commercial vehicle in this way has no choice but to have a rectangular shape with a high height unlike a passenger car. In order to arrange a plurality of battery modules, there is no choice but to arrange the battery modules in multiple layers. At the same time, the position of the battery pack is placed at the outermost part of the vehicle, so that high crush safety is required in consideration of a collision accident.

DETAILED DESCRIPTION OF THE INVENTION

Technical Problem

It is an object of the present disclosure to provide a battery pack excellent in compression stability and having a simplified battery module fixing structure, and a method for manufacturing the same.

The problem to be solved by the present disclosure is not limited to the above-mentioned problems, and other problems not mentioned should be clearly understood by those skilled in the art from the following description.

Technical Solution

In order to achieve the above objects, a battery pack according to one embodiment of the present disclosure comprises: an upper case and lower case; a battery module stack in which battery modules are stacked between the upper case and the lower case; a longitudinal square tube formed in the left and right directions of the stacked battery modules and mounted on the battery module stack; a vertical square tube formed in the vertical direction of the stacked battery modules and mounted on the battery module stack; and a horizontal square tube formed in the front and rear directions of the stacked battery modules and mounted on the battery module stack, wherein the longitudinal square tube is formed of a plurality of tubes, and the plurality of longitudinal square tubes are stacked and arranged in the vertical direction between the stacked battery modules so as to be coupled with all of the battery modules formed in the left and right directions at an uppermost part and a lowermost part, wherein the vertical square tubes is formed of a plurality of tubes, and the plurality of vertical square tubes are coupled to all the parts of the longitudinal square tubes respectively located on a plurality of axes of the stacked vertical square tubes among the stacked longitudinal square tubes in the four-direction outer periphery of the battery module stack, and wherein the horizontal square tubes is formed of a plurality of tubes, and the plurality of horizontal square tubes are coupled to all the parts of each of the vertical square tubes respectively located on a plurality of axes of the plurality of vertical square tubes, from the outside of the plurality of vertical square tubes.

In order to achieve the above objects, a method for manufacturing a battery pack according to one embodiment of the present disclosure includes: the steps of: stacking and arranging a plurality of longitudinal square tubes mounted on the battery module stack in a vertical direction between the stacked battery modules so as to be coupled integrally with the battery modules formed in the left and right directions at the uppermost part and the lowermost part; coupling a plurality of vertical square tubes with all of the longitudinal square tubes respectively located on a plurality of longitudinal axes of the stacked longitudinal square tubes in the four-direction outer periphery of the battery module stack; and in the outside of the plurality of vertical square tubes, coupling a plurality of horizontal square tubes with all of the parts of the vertical pipes respectively located on a plurality of axes in the front and rear directions among the plurality of vertical square tubes.

The plurality of longitudinal square tubes may include: a plurality of first longitudinal square tubes formed at both ends of the lowermost parts of the stacked battery modules;

at least one second longitudinal square tube formed between the plurality of first longitudinal square tubes at the lowermost parts of the stacked battery modules; a plurality of third longitudinal square tubes formed at both ends of a plurality of longitudinal square tubes formed between the uppermost part of the stacked battery modules and the stacked battery modules; and at least one fourth longitudinal square tube formed between the plurality of third longitudinal square tubes excluding the plurality of third longitudinal square tubes formed on the uppermost part of the stacked battery modules.

The battery pack may include a heat sink formed between the battery modules and the plurality of longitudinal square tubes, and a heat sink insulator that is arranged between the heat sink and a battery module located below the heat sink so that the heat sink is into close contact with the battery module.

The plurality of first longitudinal square tubes and the plurality of third longitudinal square tubes may be coupled to the heat sink.

Connecting parts are formed on both sides of the plurality of first longitudinal square tubes and the plurality of third longitudinal square tubes, and the plurality of first longitudinal square tubes or the plurality of third longitudinal square tubes may be coupled to the heat sink via the connecting part.

The at least one second longitudinal square tube and the at least one fourth longitudinal square tube may have a cut-out part formed therein, and the heat sink is inserted into the cut-out part.

The heat sink insulator includes a first heat sink insulator formed in the center; and second and third heat sink insulators formed on both sides, the second longitudinal square tubes are formed of two or more tubes, the first heat sink insulator is formed between the plurality of second longitudinal square tubes and between the plurality of fourth longitudinal square tubes, and the second and third heat sink insulators are formed between the first longitudinal square tubes at both ends and the second longitudinal square tubes closest to each other, and between the third vertical square tube at both ends and the fourth longitudinal square tubes closest to each other.

The battery pack further includes a cooling water pipe for supplying cooling water to the heat sink, wherein the cooling water pipe is formed on one surface of the battery module stack.

A tongs part is formed on one side of the heat sink insulator, and the cooling water pipe may be fixed through the tongs part.

A support portion supporting the battery module stack and coupled to the lower case may be formed in the plurality of first longitudinal square tubes and the at least one second longitudinal square tube.

The plurality of vertical square tubes may include a plurality of first vertical square tubes which are coupled to one of the plurality of first longitudinal square tube, and the plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes; and a plurality of second vertical square tubes which are coupled to one of the plurality of second longitudinal square tubes, and one of the plurality of fourth longitudinal square tubes and the third longitudinal square tubes located on the same vertical axis as one of the plurality of second longitudinal square tubes.

A plurality of longitudinal square tube connecting parts are formed on one side of the first vertical square tube, and the plurality of longitudinal square tube connecting parts may be coupled to a first longitudinal square tube connecting part formed on one of the plurality of first longitudinal square tubes, and a first longitudinal square tube connecting part formed on the plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes.

A plurality of longitudinal square tube connecting parts are formed on one side of the second vertical square tube, and the plurality of v longitudinal square tube connecting parts may be coupled to a second longitudinal square tube connecting part formed on one of the plurality of second longitudinal square tubes, a second longitudinal square tube connecting part formed on the plurality of fourth longitudinal square tubes located on the same vertical axis as one of the plurality of fourth longitudinal square tubes, and a second longitudinal square tube connecting parts formed on one of the plurality of third longitudinal square tubes.

The plurality of vertical square tubes include a plurality of second longitudinal square tubes that are coupled to one of the plurality of first longitudinal square tubes, and a plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes, a plurality of longitudinal square tube connecting parts are formed on one side of the second longitudinal square tube, the plurality of longitudinal square tube connecting parts are coupled to a second longitudinal square tube connecting part formed on one of the plurality of first longitudinal square tubes, and a second longitudinal square tube connecting parts formed on the plurality of third longitudinal square tubes located on the same vertical axis as one of the plurality of first longitudinal square tubes.

The plurality of horizontal square tubes may be coupled to the plurality of second longitudinal square tubes located coaxially in the front and rear directions.

A plurality of vertical square tube connecting parts may be formed in the plurality of horizontal square tubes, and the plurality of vertical square tube connecting parts may be coupled to the horizontal square tube connecting part is formed in the plurality of second vertical square tubes.

The battery pack may further include a plurality of brackets fixing the battery module stack to the lower case.

The method may further include the steps of: fixing the battery module stack to the lower case via a bracket and coupling the upper case to the lower case, after the step of combining the plurality of horizontal square tubes.

Advantageous Effects

The battery pack and its manufacturing method according to an embodiment of the present disclosure improve the compression stability of the battery modules and at the same time, provide weight reduction and price competitiveness, by fixing the stacked battery modules using most simplified square tubes.

DETAILED DESCRIPTION OF THE EMBODIMENTS

It should be appreciated that the exemplary embodiments, which will be described below, are illustratively described to help understand the present disclosure, and the present disclosure may be variously modified to be carried out differently from the exemplary embodiments described herein. However, in the description of the present disclosure, the specific descriptions and illustrations of publicly known functions or constituent elements will be omitted when it is determined that the specific descriptions and illustrations may unnecessarily obscure the subject matter of the present disclosure. In addition, to help understand the present disclosure, the accompanying drawings are not illustrated based on actual scales, but parts of the constituent elements may be exaggerated in size.

As used herein, terms such as first, second, and the like may be used to describe various components, and the terms are used only to discriminate one component from another component.

Further, the terms used herein are used only to describe exemplary embodiments, and are not intended to limit the present disclosure. A singular expression includes a plural expression unless they have definitely opposite meanings in the context. It should be understood that the terms “comprise”, “include”, and “have” as used herein are intended to designate the presence of stated features, numbers, steps, operation, constitutional elements, or combinations thereof, but it should be understood that they do not preclude a possibility of existence or addition of one or more other features, numbers, steps, operation, constitutional elements, or combinations thereof.

The order of the figures corresponding to the content of the invention described later shows the process for assembling the battery pack according to an embodiment of the present disclosure in order. Further, the arrangement directions of the components forming the present disclosure described later will be described in the directions corresponding to the front and rear directions, the left and right directions, and the up and down directions shown inFIG.15which is a representative figure. The reference of the directions is in accordance with the arrangement direction of the battery modules of the present disclosure.

Hereinafter, referring mainly toFIGS.1to8, the longitudinal square tube and the peripheral configuration connected to the longitudinal square tube according to an embodiment of the present disclosure will be described.FIG.1is a perspective view illustrating first and second longitudinal square tubes and a heat sink insulator according to an embodiment of the present disclosure.FIG.2is a perspective view illustrating the assembled configuration ofFIG.1and a heat sink and battery modules according to an embodiment of the present disclosure.FIG.3is a perspective view illustrating a state in which a plurality of battery modules are stacked together with a plurality of longitudinal square tubes according to an embodiment of the present disclosure.FIG.4is a top view (a), a perspective view (b), and a side view (c) of a first longitudinal square tube according to an embodiment of the present disclosure.FIG.5is a top view (a), a perspective view (b), and a side view (c) of a second longitudinal square tube according to an embodiment of the present disclosure.FIG.6is a top view (a), a perspective view (b), and a side view (c) of a third longitudinal square tube according to an embodiment of the present disclosure.FIG.7is a top view (a), a perspective view (b), and a side view (c) of a fourth longitudinal square tube according to an embodiment of the present disclosure.FIG.8is a view illustrating a state in which each longitudinal square tube is coupled to the battery module stack according to an embodiment of the present disclosure.

First, referring toFIG.8, the overall arrangement of a plurality of longitudinal square tubes will be described.

A plurality of longitudinal square tubes300are formed in the front and rear directions of the stacked battery modules210and are mounted on the battery module stack200, and stacked and arranged vertically between the stacked battery modules210so as to be coupled with both the battery modules210formed in the left and right directions of the uppermost part and the lowermost part.

A plurality of longitudinal square tubes300for fixing the plurality of battery modules210of the battery module stack200may include a plurality of first longitudinal square tubes310formed at both (or opposite) ends of the lowermost parts of the stacked battery modules210, at least one second longitudinal square tube320formed between the plurality of first longitudinal square tubes310at the lowermost part of the stacked battery modules210, a plurality of third longitudinal square tubes330formed at the uppermost part of the stacked battery modules210and both ends of the plurality of longitudinal square tubes300formed between the stacked battery modules, and at least one fourth longitudinal square tube340formed between the plurality of third longitudinal square tubes330excluding the plurality of third longitudinal tubes330formed at the uppermost part of the stacked battery modules.

According to an embodiment of the present disclosure, the second longitudinal square tubes320can be arranged as two second longitudinal square tubes320maintaining the same distance as the first longitudinal square tubes310at both ends, between the first longitudinal square tubes310located at the lower part of both ends of the battery module stack200.

Also, according to an embodiment of the present disclosure, the fourth longitudinal square tubes340may be arranged as two fourth longitudinal square tubes340maintaining the same distance as the third longitudinal square tubes330at both ends, between the two third longitudinal square tubes330located on the same plane among the plurality of third longitudinal square tubes330formed at both ends of the battery module stack200. Further, the fourth longitudinal square tubes340may be stacked and arranged two by two in the vertical direction between the third longitudinal square tubes330so as to correspond to the vertically stacked positions of the plurality of third longitudinal square tubes330located at both ends of the lower part of each of the stacked battery modules210.

According to an embodiment of the present disclosure, the battery modules210are stacked and arranged in four stages in the vertical direction. The third longitudinal square tubes330at both ends of each of the four-stage battery module210layers, and two fourth longitudinal square tubes340arranged so as to maintain a constant distance with the third longitudinal square tubes330between the third longitudinal square tubes330, may be stacked and arranged in four stages.

Hereinafter, referring mainly toFIGS.1and2, the arrangement of the heat sink600and the heat sink insulator610according to an embodiment of the present disclosure will be described.

Referring toFIGS.1and2, the battery module210according to an embodiment of the present disclosure may have a structure in which a plurality of battery modules210are coupled in a horizontal direction. According to an embodiment of the present disclosure, the two battery modules210may be coupled in a direction perpendicular to the lengthwise direction of the battery module210. As described above, the two battery modules210may be stacked and disposed in the vertical direction to form the battery module stack200.

Referring toFIG.2, a heat sink600may be arranged at the lower part of the battery modules210according to an embodiment of the present disclosure. In addition, a first longitudinal square tube310for fixing the heat sink insulator610and the heat sink insulator610may be disposed at the lower part of the heat sink600.

The heat sink600may be formed between the battery modules210and the plurality of longitudinal square tubes300. The battery module according to the present disclosure is an indirect water cooling module, and may cool heat generated from the battery module via a heat sink600located under the battery module. Therefore, the heat sink600may be disposed in close contact with the lower part of the battery modules210.

Connecting parts601may be formed at both ends of the heat sink600. As shown inFIG.2, the connecting part601may be coupled with the connecting part311formed in the first longitudinal square tube310. According to an embodiment of the present disclosure, the connecting parts601may be formed two by two at both ends of the heat sink600, and the connecting part311formed in the first longitudinal square tubes310is also formed in two on both sides. The connecting part601of the heat sink600and the connection part311of the first longitudinal square tube310may be coupled to each other. At this time, in order to suppress the flow in the plane of the heat sink600, the connecting part311of the first longitudinal square tube310and the connecting part601of the heat sink600may be fastened and fixed with bolts and nuts.

According to an embodiment of the present disclosure, two battery modules210are stacked and arranged in the vertical direction, and the heat sink600may be arranged at the lower part of the two battery modules210formed on each layer. Therefore, the heat sinks600are disposed at the lower part of the battery modules210stacked in the vertical direction so as to be in close contact with each other, thereby cooling heat generated from all the battery modules210.

The configuration of the heat sink600formed at the lower part of the battery modules210shown inFIG.2and the first longitudinal square tube310may be equally applied to the structure of the battery module210that is stacked and arranged upward as shown inFIG.3. However, in the structure stacked upwards, a third longitudinal square tube330may be formed at a position of the first longitudinal square tube310as shown inFIG.3.

Therefore, in addition to the heat sink600formed under the battery modules210formed at the lowermost part, the connection parts601as shown inFIG.2are formed even at both ends of the heat sinks600formed at the lower part of each of the battery modules210stacked upward, wherein the connecting part601may be coupled to the connecting part331formed in the third longitudinal square tube330shown inFIG.6. According to an embodiment of the present disclosure, the connecting part601of the heat sinks600formed above the bottom battery modules210is also formed in the same structure as the heat sink600formed below the bottom battery module210. The connecting parts331formed on the third longitudinal square tubes330are also formed in two on both sides, so that the connecting parts601of the heat sink600and the connecting parts331of the third longitudinal square tubes330can be coupled with each other for each layer. Similarly, in order to suppress the flow in the plane of the heat sink600, the connecting parts331of the third longitudinal square tube330and the connecting part601of the heat sink600may be fastened and fixed with bolts and nuts.

The second longitudinal square tube320may be arranged below the central part of the heat sink600. Referring toFIG.5, a cut-out part323is formed in the central part of the second longitudinal square tube320, and the central part of the heat sink600may be inserted into the cut-out part323and fixed by the second longitudinal square tube320.

The configurations of the heat sink600and the second longitudinal square tube320shown inFIG.2may be similarly applied to the structure of the battery module210that is stacked on the upper side as shown inFIG.3. However, in the structure stacked on the upper side, a fourth longitudinal square tube340may be formed at a position of the second longitudinal square tube320as shown inFIG.3.

The heat sink insulator610may be arranged between the heat sink600and the battery modules210located below the heat sink600, so that the heat sink600may be in close contact with the battery module610. The heat sink insulator610may be formed of plastic having excellent electrical insulation and thermal insulation performance.

The plurality of square tubes according to an embodiment of the present disclosure is required to have a certain thickness for assembling bolts and nuts. In order to minimize the stacking height of the battery modules, the thickness of the heat sink may be thinner than that of the plurality of square tubes in the process of forming the heat sink to be thinner.

As the thickness of the heat sink becomes thinner than the thickness of the square tube in this way, there may be a gap between the battery modules and the heat sink. Thus, to reduce the gap between the bottom of the battery module and the heat sink, the heat sink insulator610is arranged at the lower part of the heat sink600, so that the heat sink600can be in close contact with the battery modules210.

According to an embodiment of the present disclosure, the thickness of the heat sink600is 10 mm including a thermal pad, the thickness of the heat sink insulator610is 15 mm, and the thickness of the square tube is 25 mm. Through this, it can be seen that the space in which the thickness of the square tube is formed can be filled through the heat sink600and the heat sink insulator610.

The heat sink insulator610may include a first heat sink insulator611formed in the center and second and third heat sink insulators612and613formed on both sides. The first heat sink insulator611may be formed between the plurality of second longitudinal square tubes320, and the second and third heat sink insulators612and613may be formed between the plurality of second longitudinal square tubes320and the first longitudinal square tubes310at both ends.

According to an embodiment of the present disclosure, as shown inFIG.2, the first heat sink insulator611may be formed between the two second longitudinal square tubes320, and the second and third heat sink insulators612and613may be formed between a first longitudinal square tube310formed at both ends of the battery module stack200and a second longitudinal square tube320closest to each of the first longitudinal square tube310.

The configuration of the heat sink insulator610formed at the lower part of the heat sink600and the first and second longitudinal square tubes310and320as shown inFIG.2may be similarly applied to the structure of the battery module210that is stacked and disposed on the upper side. However, in the structure stacked on the upper side, a third longitudinal square tube330may be formed at a position of the first longitudinal square tube310, and a fourth longitudinal square tube340may be formed at a position of the second longitudinal square tube320.

More specifically, as shown inFIG.3, the first heat sink insulator611may be formed between the two fourth longitudinal square tubes340, and the second and third heat sink insulators612and613may be formed between the third longitudinal square tubes330formed at both ends of the battery module stack200, and the fourth longitudinal square tube340closest to each of the third longitudinal square tubes330.

A tongs part610ais formed at one end of the heat sink insulator610to fix a cooling water pipe described later. The arrangement structure of the heat sink insulator610, the heat sink600, and the first and third longitudinal square tubes310and330can also be confirmed by the cross section shown inFIG.20.

Hereinafter, the structure of the first to fourth longitudinal square tubes according to an embodiment of the present disclosure will be described with reference mainly toFIGS.4to7.

Referring toFIG.4, the first longitudinal square tube310may include a connecting part311coupling with the connecting part601of the heat sink600, first vertical square tube connecting parts312and313connected to the first vertical square tube410, second vertical square tube connecting parts314and315connected to the second vertical square tube420, and a support part316that supports the entire battery module stack200and at the same time, couples with the longitudinal square tube connecting part122of the lower case120shown inFIG.22.

According to another embodiment of the present disclosure, the first longitudinal square tube310may include the1-1vertical square tube connecting parts317and318together with the first vertical square tube connecting parts312and313. Through this, as shown inFIG.12, the first vertical angle pipe410may be respectively coupled to the first vertical square tube connecting parts312and313as shown inFIG.12, and the first vertical square tube410may be coupled with the1-1vertical square tube connecting parts317and318as shown inFIG.18.

The connecting part311may be formed in grooves formed on both sides of the first longitudinal square tube310, respectively. The groove is a space formed by removing two adjacent two surfaces of the square tube, and the connecting part311is formed on one of the two unremoved surfaces of the groove and may be coupled to the connecting part601of the heat sink600inserted into the groove. The connecting pars311formed on both sides may be formed in parallel.

The first vertical square tube connecting parts312and313and the1-1vertical square tube connecting parts317and318may be formed on the remaining surface of the groove on which the connecting part311is not formed. The first vertical square tube connecting parts312and313and the1-1vertical square tube connecting parts317and318may be formed in parallel, respectively. The first vertical square tube connecting part312may be formed outside the1-1vertical square tube connecting part317, and the first vertical square tube connecting part313may also be formed outside the1-1vertical square tube connecting part318.

The second vertical square tube connecting parts314and315may be formed at both ends of one surface of the first longitudinal square tube310and coupled to the second vertical square tube420, respectively.

Both ends of the first longitudinal square tube310may be formed to be cut in the oblique direction. The oblique direction formed at one end of the first longitudinal square tube310and the oblique direction formed at the other end may be symmetrically formed. One surface of both ends of the first longitudinal square tube310may form a support part316which is protruded perpendicularly to the lengthwise direction of the first longitudinal square tube310.

Referring toFIG.5, the second longitudinal square tube320may include second vertical square tube connecting parts321and322connected to the second vertical square tube420, a cut-out part323into which the heat sink600is inserted, and a support portion324that supports the entire battery module stack200and at the same time couples with the longitudinal square tube connecting part122of the lower case120shown inFIG.22.

The second vertical square tube connecting parts321and322are formed on both ends of one side of the second longitudinal square tube320, and may be coupled with the second vertical square tube420as shown inFIG.12. The cut-out part323is formed in the center of the second longitudinal square tube320, and a part of the plate-shaped heat sink600may be inserted into the cut-off space.

Both ends of the second longitudinal square tube320may be formed to be cut in the oblique direction. The oblique direction formed at one end of the second longitudinal square tube320and the oblique direction formed at the other end may be formed symmetrically to each other. One surface of both ends of the second longitudinal square tube320may form a support portion324which is protruded perpendicular to the lengthwise direction of the second longitudinal square tube320.

Referring toFIG.6, the third longitudinal square tube330may include a connecting part331coupled with the connecting part601of the heat sink600, first vertical square tube connecting parts332and333connected to the first longitudinal square tube410, and second vertical square tube connecting parts334and335connected to the second vertical square tube420.

According to another embodiment of the present disclosure, the third longitudinal square tube330may include the1-1vertical square tube connecting parts336and337together with the first vertical square tube connecting parts332and333. Through this, the first vertical square tube410may be coupled to the first vertical square tube connecting parts332and333, respectively, as shown inFIG.12, and the first vertical square tube410may be coupled to the1-1vertical square tube connecting parts336and337as shown inFIG.18.

The connecting parts331may be formed in grooves formed on both sides of the third longitudinal square tube330, respectively. The groove is a space formed by removing two adjacent surfaces on both sides of the square tube, and the connecting part331is formed on one of the two unremoved surfaces of the groove, and may be coupled to the connecting part601of the heat sink600inserted into the groove. Further, as shown inFIG.20, it may be coupled with the BMS700and BDU800located at the uppermost part of the battery module stack200. The connecting parts311formed on both sides may be formed in parallel.

The first vertical squire tube connecting parts332and333and the1-1vertical square tube connecting parts336and337may be formed on the remaining surface of the groove on which the connecting part331is not formed. The first vertical square tube connecting parts332and333and the1-1vertical square tube connecting parts336and337may be formed in parallel, respectively. The first vertical square tube connecting part332may be formed outside the1-1vertical square connecting part336, and the first vertical square tube connecting part333may also be formed outside the second vertical square tube connecting part337.

The second vertical square tube connecting portions334and335are formed on both ends of one surface of the third longitudinal square tube330and may be coupled to the second vertical square tube420, respectively.

Both ends of the third longitudinal square tube330may be formed to be cut in an oblique direction. The oblique direction formed at one end of the third vertical square tube330and the oblique direction formed at the other end may be formed symmetrically to each other.

Referring toFIG.7, the fourth longitudinal square tube340may include second vertical square tube connecting parts341and342connected to the second vertical longitudinal square tube420, and a cut-out part343into which the heat sink600is inserted.

The second vertical square tube connecting parts341and342are formed on both ends of one surface of the fourth longitudinal square tube340, and may be coupled with the second vertical square tube420as shown inFIG.12. The cut-out part343is formed in the center of the fourth longitudinal square tube340, and a part of the plate-shaped heat sink600may be inserted in the cut-out space.

Both ends of the fourth longitudinal square tube340may be formed to be cut in the oblique direction. The oblique direction formed at one end of the fourth longitudinal square tube340and the oblique direction formed at the other end may be formed symmetrically with each other.

Hereinafter, the structure and arrangement of the vertical square tube according to an embodiment of the present disclosure will be described with reference toFIGS.9to12.

FIG.9is a view illustrating the configuration ofFIG.8and a plurality of vertical square tubes according to an embodiment of the present disclosure.FIG.10is a top view (a), a perspective view (b), and a side view (c) of a first vertical angle tube according to an embodiment of the present disclosure.FIG.11is a top view (a), a perspective view (b), and a side view (c) of a second vertical angle tube according to an embodiment of the present disclosure.FIG.12is a view illustrating a state in which a plurality of vertical square tubes are coupled to the battery module stack ofFIG.9.

First, the configuration and arrangement of the vertical square tube according to an embodiment of the present disclosure will be described with reference mainly toFIGS.9and12.

Referring toFIGS.9and12, a plurality of vertical square tube400according to an embodiment of the present disclosure are formed in the vertical direction of the stacked battery modules210, and are mounted on the battery module stack200, and coupled with all parts of the stacked longitudinal square tubes300located on a plurality of axes in the vertical direction among the stacked longitudinal square tubes300, in the four-direction outer periphery of the battery module stack200.

The battery module stack200and the plurality of longitudinal square tube400for fixing the plurality of longitudinal square tubes300formed on the battery module stack200may include a plurality of first vertical square tubes that are all coupled to one of the first longitudinal square tubes310and a plurality of third longitudinal square tubes330located on the same vertical axis as one of the plurality of first longitudinal square tubes310, and a plurality of second vertical square tubes, all of which are all coupled with one of the second vertical pipes320, and a plurality of second vertical square tubes420, all of which are coupled with the plurality of fourth longitudinal square tubes340located on the same vertical axis as one of the plurality of second longitudinal square tubes320.

The first vertical square tube410may be integrally coupled with one of the plurality of first longitudinal square tubes310and the plurality of third longitudinal square tubes330located on the same vertical axis as one of the plurality of first longitudinal square tubes310.

The first vertical square tube410has a plurality of longitudinal square tube connecting parts formed on one side, and the plurality of longitudinal square tube connecting parts may be coupled with first vertical square tube connecting parts312and313formed on one of the plurality of first longitudinal square tubes310, and first vertical square tube connecting parts332and333formed on a plurality of third longitudinal square tubes330located on the same vertical axis as one of the plurality of first longitudinal square tube.

According to an embodiment of the present disclosure, as illustrated inFIGS.9and12, the first vertical square tubes410may be formed in the front and rear directions of the battery modules210, respectively. In more detail, the first vertical square tube410may be formed two by two on front and rear sides of the battery modules210.

According to an embodiment of the present disclosure, one of the first vertical square tubes410on one side can be integrally coupled with the first vertical square tube connecting part312formed on the first longitudinal square tube310at the lower part on one side, and four first vertical square tube connecting parts332formed on the third longitudinal square tubes330at the upper part on one side. At this time, the first vertical square tube connecting part312and the four first vertical square tube connecting parts332are located on the same axis in the vertical direction, so that the first vertical square tube410formed in a straight shape is integrally coupled with each connecting part.

In addition, according to an embodiment of the present disclosure, one of the first vertical square tube410at the lower part on one side may be integrally coupled with a first vertical square tube connecting part313formed on the first longitudinal square tube310at the upper part on one side, and four first vertical square tube connecting parts333formed on the third longitudinal square tubes330on one side. At this time, the first vertical square tube connecting part313and the four first vertical square tube connecting parts333are located on the same axis in the vertical direction, so that the first vertical square tube410formed in a straight shape can be integrally coupled with the respective connecting parts.

In addition, according to another embodiment of the present disclosure, as shown inFIG.18, one of the first vertical square tubes410at the lower part on one side may be integrally coupled with the1-1vertical square tube connecting part317formed on the first longitudinal square tube310at the upper part on one side, and four first vertical square tube connecting parts336formed on the third longitudinal square tubes330on one side. At this time, the first vertical square tube connecting part317and the four first vertical square tube connecting parts336are located on the same axis in the vertical direction, so that the first vertical square tube410formed in a straight shape can be integrally coupled with the respective connecting parts.

Further, according to another embodiment of the present disclosure, as shown inFIG.18, one of the first vertical square tubes410at the lower end on one side may be integrally coupled with the1-1vertical square tube connecting part318formed in the first longitudinal square tube310at the upper end on one side and the third longitudinal square tube330on one side, and the four first vertical square tube connecting parts337. At this time, the first vertical square tube connecting part318and the four first vertical square tube connecting parts337are located on the same axis in the vertical direction, and the first vertical square tubes410formed in a straight shape may be integrally coupled with the respective connecting parts.

The second vertical square tube420can be coupled with one of the a plurality of fourth longitudinal square tubes340and the third longitudinal square tube330located on the same vertical axis as one of the plurality of second vertical longitudinal square tube320and one of the plurality of second longitudinal square tube320.

The second vertical square tube420has a plurality of longitudinal square tube connecting parts formed on one side, and the plurality of longitudinal square tube connecting parts can be coupled with the second vertical square tube connecting parts321322formed on one of the plurality of second longitudinal square tubes320, the second vertical square tube connecting parts341and342formed on a plurality of fourth longitudinal square tubes340located on the same vertical axis as one of the plurality of fourth longitudinal square tubes, and the second vertical square tube connecting part is334and335formed on one of the plurality of third longitudinal square tubes330.

According to an embodiment of the present disclosure, as shown inFIGS.9and12, the second vertical square tubes420may be formed in the left and right directions of the battery modules210, respectively. In more detail, the second vertical square tubes420may be formed four by four on the left and right sides of the battery modules210, respectively.

According to an embodiment of the present disclosure, one of the second vertical square tubes420on one side may be integrally coupled with the second vertical square tube connecting part321formed on the second longitudinal square tube320at the lowermost part on one side, the three second vertical square tube connecting parts341formed on the fourth longitudinal square tubes340in the center of one side, and the second vertical square tube connecting parts334formed on the third longitudinal square tube330on the uppermost part on one side. At this time, the second vertical square tube connecting part321, the three second vertical square tube connecting part341and the second vertical square tube connecting part334are located on the same axis in the vertical direction, so that the second vertical square tubes420formed in a straight shape may be integrally coupled with the respective connecting parts.

According to an embodiment of the present disclosure, one of the second vertical square tubes420on one side can be integrally coupled with the second vertical square tube connecting part322formed on the second longitudinal square tube320at the lowermost part on one side, the second vertical square tube connecting parts342formed on the fourth vertical square tubes340in the center of one side, and the second vertical square tube connecting parts335formed on the third longitudinal square tube330at the uppermost part on one side. At this time, the second vertical square tube connecting part322, the three second vertical square tube connecting parts342, and the second vertical square tube connecting parts335are located on the same axis in the vertical direction, so that a second vertical square tube420formed in a straight shape can be integrally coupled with the respective connecting parts.

According to an embodiment of the present disclosure, one of the second vertical square tubes420on one side can be integrally coupled with the second vertical square tube connecting part314formed on the first vertical angle pipe310at the lower part on one side and the four second vertical square tube connecting parts334formed on the third longitudinal square tubes330at the upper part on one side. At this time, the second vertical square tube connecting part314and the four second vertical square tube connecting parts334are located on the same axis in the vertical direction, sot that the second vertical square tubes420formed in a straight shape may be integrally coupled with the respective connecting parts.

According to an embodiment of the present disclosure, one of the second vertical square tubes420on one side can be integrally coupled with the second vertical square tube connecting part315formed on the first vertical longitudinal square tube310at the lower part on one side and the four second vertical square tube connecting parts335formed on the third longitudinal square tubes330at the upper part on one side. At this time, the second vertical square tube connecting part315and the four second vertical square tube connecting parts335are located on the same axis in the vertical direction, so that the second vertical square tubes420formed in a straight shape may be integrally coupled with the respective connecting parts.

Hereinafter, the vertical square tube400according to an embodiment of the present disclosure will be described with reference mainly toFIGS.10and11.

Referring toFIG.10, the first vertical square tube410may include a longitudinal square tube connecting part411connected to a longitudinal square tube300. According to an embodiment of the present disclosure, the battery modules210are stacked in five stages, and the longitudinal square tube connecting part411is also formed in five stages at regular intervals, so that it can be coupled with each of the first or third longitudinal square tubes310and330disposed at the position corresponding to each position.

More specifically, the longitudinal square tube connecting part411aformed at one end may be coupled with the first vertical square tube connecting parts312and313formed in the first longitudinal square tube310or the1-1vertical square tube connecting parts317and318. Further, the longitudinal square tube connecting part (411b) excluding the longitudinal square tube connection part411aformed at one end can be coupled with the first vertical square tube connecting parts332and333formed on the third longitudinal square tube330or the1-1vertical square tube connecting parts336and337.

Referring toFIG.11, the second vertical square tube420may include a longitudinal square tube connecting part421connected to a longitudinal square tube300, a horizontal square tube connecting part422connected to a horizontal square tube described later, and a bracket connecting part423for coupling with a bracket that connects the lower case and the battery module stack200, which will be described later.

According to an embodiment of the present disclosure concerning the longitudinal square tube connecting part421, the battery modules210are stacked in five stages. The longitudinal square tube connecting part421is also formed in five at regular intervals, and can be integrally coupled with the connecting parts formed in the second, fourth, or third longitudinal square tubes320,340, and330arranged at the position corresponding to each position.

More specifically, the longitudinal square tube connecting part421aformed at one end may be coupled to the second longitudinal square tube connecting parts321and322formed on the longitudinal square tube320. Further, the longitudinal square tube connecting part421bformed at the other end may be coupled to the second vertical square tube connecting parts334and335formed on the third longitudinal square tube330. In addition, the longitudinal square tube connecting part421cformed in the center may be coupled to the second vertical square tube connecting parts341and342formed in the fourth longitudinal square tube340.

Hereinafter, the structure and arrangement of the horizontal square tube according to an embodiment of the present disclosure will be described with reference mainly toFIGS.13to15.

FIG.13is a view illustrating the configuration ofFIG.12and horizontal square tubes according to an embodiment of the present disclosure.FIG.14is a top view (a), a perspective view (b), and a side view (c) of horizontal square tubes according to an embodiment of the present disclosure.FIG.15is a view illustrating a state in which a plurality of horizontal square tubes are coupled to the battery module stack ofFIG.12.

Referring toFIGS.13to15, the horizontal square tubes500according to an embodiment of the present disclosure are formed in the front and rear directions of the stacked battery modules, and mounted on the battery module stack200, and coupled with all the part of each of the vertical square tubes400located on a plurality of axes in the front and rear directions among the plurality of vertical square tubes400, in the outside of each of the plurality of vertical square tubes400.

The plurality of horizontal square tubes500may be coupled with a plurality of second vertical square tubes420located on the same axis in the front and rear directions. A plurality of vertical square tube connecting parts501are formed in the horizontal square tube500. The plurality of vertical square connecting parts501may be coupled to the horizontal square tube connecting parts422formed on the plurality of second vertical square tubes400.

According to an embodiment of the present disclosure, the horizontal square tube500may be disposed one by one at each of the left and right sides of the battery module. Each of the horizontal square tubes500may be integrally coupled with the connecting parts422located at the uppermost part of the horizontal square tube connecting parts422formed in each of the second vertical square tubes420.

Referring toFIGS.14and17, the vertical square tube connecting part501may be formed two by two in the center and one by one at both ends. Therefore, the two vertical square tube connecting parts501adisposed in the center are coupled with the two connecting parts422located at the uppermost part of the two second vertical square tubes420located in the center of the battery module stack200, and the two vertical square tube connecting parts501bdisposed at both ends may be coupled to the two connecting parts422located at the uppermost part of the second vertical square tubes420located at both ends of the battery module stack200.

As shown inFIG.15, in the water-cooled battery module structure according to the present disclosure, the cooling water pipe900may be formed on one surface of the battery module stack200so as to supply cooling water to the heat sink600. The cooling water pipe900may be fixed to one surface of the battery module stack200through the tongs610aformed on one side of the heat sink insulator610.

Hereinafter, the overall configurations and effects of each of the aforementioned square tubes will be described with reference to the figures according to the present disclosure.

The coupling between the above-described vertical square tube300, the vertical square tube400, and the horizontal square tube500is made through a connecting part formed in each of the tubes. According to an embodiment of the present disclosure, the coupling of the respective connecting parts may be achieved through bolt-nut fastening. At the time of mutual fastening, each tube needs hole drilling, nut welding, back cutting-out for access to welding tools, bracket welding attachment, etc. Thereby, the final shape type can be classified.

In the respective square tubes, the first to fourth longitudinal square tubes310,320,330and340are arranged in the left and right directions based on the battery module, the first and second vertical square tubes410and420are arranged vertically in the front-back and up-down directions based on the battery module, the horizontal square tubes500are arranged in the front and rear directions based on the battery module, so that a horizontal-vertical-height lattice structure is formed on the outer periphery of the battery modules210around the battery modules210, thereby constraining six degrees of freedom of the battery modules210.

The longitudinal square tube300, the vertical square tube400and the horizontal square tube500according to an embodiment of the present disclosure are mechanically fixed and pressure-resistant rigid structures of the battery modules210. As shown in the figures of the respective square tubes, steel square tube with a square cross section can be used. The square tube has dimensions of 20 to 40 mm in width and 20 to 40 mm in length, which may be a value considering the bolt-nut assembly surface used when assembling the vehicle parts of the battery pack.

The square tube may have a thickness of 1.0 mm to 3.0 mm. The cross-sections of the square tubes shown inFIGS.4to7,10,11, and14may be formed to have a width of 40 mm, a length of 25 mm, and a thickness of 2 mm. As described above, although there are some modifications of the connecting part, the cut-out part, the support part, etc. in the square tubes, the cross-sectional outer size of each of the seven types of square tubes is the same, and thus, the cross-section of respective square tubes is simplified as much as possible, so that price competitiveness of parts can be secured.

According to the present disclosure, in a single section, the fixed structure design of the battery module stack200is completed with only total seven types of square tubes of the first longitudinal square tube310, the second longitudinal square tube320, the third longitudinal square tube330, the fourth longitudinal square tube340, the first vertical square tube410, the second vertical square tube420and the horizontal square tub500, and brackets130, so that the components are simple and price competitiveness can be secured.

Further, as the square tubes are disposed more outside than the outside of the battery modules, the square tubes coupled to each other at the time of crimping the battery module stack200receives a load first, so that a force transmitted to the battery modules due to the high stiffness of the square tubes is lowered, thereby improving crimping stability.

In addition, compared to a structure in which modules stacked in multiple layers are fixed by bonding between press plate structures, the weight specific stiffness of the square tubes according to an embodiment of the present disclosure is excellent, and a relatively lightweight battery pack can be manufactured.

Hereinafter, a battery module stack in which BMS and BDU are combined according to an embodiment of the present disclosure will be described with reference toFIGS.16to20.

FIG.16is a view illustrating a state in which BMS and BDU are coupled to a battery module stack according to an embodiment of the present disclosure.FIG.17is a front view ofFIG.16.FIG.18is a rear view ofFIG.16.FIG.19is a top view ofFIG.16.FIG.20is a cross-sectional view illustrating a portion A-A′ ofFIG.19.

Referring toFIGS.16to20, a BMS700and a BDU800may be coupled to the top of the battery module stack200of the present disclosure.

The BMS700refers to a battery management system (BMS), and serves to manage the temperature or voltage of battery modules. The BDU800refers to a battery disconnect unit, and serves to control electrical connection of battery modules.

Referring toFIG.16, the BMS700and the BDU800may be arranged side by side on the upper part of the battery module stack200. Referring toFIG.17, the BMS700and the BDU800may be arranged between the third longitudinal square tubes330disposed at the uppermost part of the battery module stack200.

According to an embodiment of the present disclosure, the BMS700and the BDU800may be coupled with the third longitudinal square tubes330disposed at the uppermost part of the battery module stack200. More specifically, as shown inFIG.19, the four connecting parts701formed on the side of the BMS700, and the four connecting parts801formed on the side surfaces of the BDU800are coupled with the connecting parts331formed in the third longitudinal square tubes330, respectively, so that the BMS700and the BDU800may be coupled to the battery module stack200.

According to an embodiment of the present disclosure, the connecting parts701of the BMS700and the connecting parts331of the third longitudinal square tube330may be coupled with a bolt702. The connecting part801of the BDU800and the connecting part331of the third longitudinal square tube330may be similarly coupled with a bolt802. However, the combination method is not limited thereto, and the BMS700and the BDU800may be fixed to the battery module stack200through various coupling methods.

Hereinafter, the case mounting structure of a bracket and a module stack including a battery according to an embodiment of the present disclosure will be described with reference toFIGS.21to23.

FIG.21is a view illustrating a battery module stack, upper and lower cases, and brackets according to an embodiment of the present disclosure.FIG.22is a view illustrating a lower case according to an embodiment of the present disclosure.FIG.23is a view illustrating a state in which the upper and lower cases are assembled according to an embodiment of the present disclosure.

Referring toFIGS.21to23, the battery module stack200according to an embodiment of the present disclosure may be mounted inside the upper case110and the lower case120to physically and chemically protect the battery modules210from the outside.

The battery module stack200may be coupled to the lower case120via the bracket130shown inFIG.21. The bracket130includes first brackets131formed on the left side of the battery module and second brackets132formed on the right side of the battery module. According to an embodiment of the present disclosure, each of the first and second brackets131and132may be formed of four, and is disposed four by four on the left and right sides of the battery module stack200, so that the battery module stack200can be fixed to the lower case120.

One end of the bracket130may be coupled to the bracket connecting part121formed on the lower case120. According to an embodiment of the present disclosure, a first bracket connecting part121aformed in four is formed on one side of the upper end of the lower case120, and the four first bracket connecting parts121amay be respectively coupled to the four first brackets131. Further, a second bracket connecting part121bformed in four is formed on the other side of the upper end of the lower case120, and the four second bracket connecting parts121bmay be coupled to the four second brackets132, respectively.

The other end of the bracket130may be coupled to the bracket connecting part423of the second vertical square tube420. According to an embodiment of the present disclosure, the four second vertical square tubes420are formed on the left side of the battery module stack200, and the bracket connecting parts423formed on each of the four second vertical square tubes420may be coupled to the other ends of the four first brackets131, respectively. Further, four second vertical square tubes420are formed on the right side of the battery module stack200, and bracket connecting parts423formed on each of the four second vertical square tubes420may be coupled to the other ends of the four second brackets132, respectively.

The longitudinal square tube connecting part122may be formed at the lower part of the lower case120. According to an embodiment of the present disclosure, the support parts316formed at both ends of the first longitudinal square tubes310disposed at both ends of the lowermost part of the battery module stack200can be coupled with the four longitudinal square tube connecting parts122adisposed two by two at each end of the lower case120. Further, the support parts324formed at both ends of the second longitudinal square tubes320disposed in the center of the lowermost part of the battery module stack200can be coupled with the four longitudinal square tube connecting part122barranged two by two at each end of the lower case120.

The bracket connection part423may be formed in the middle of each second vertical square tube, and the bracket130coupled to the bracket connecting part423are located at an intermediate height of the battery module stack200to effectively suppress the flow of the battery module stack200having a high center of gravity.

Hereinafter, a method of manufacturing a battery pack according to an embodiment of the present disclosure will be described with reference toFIGS.8,12, and15.

FIG.8is a view illustrating a state in which longitudinal square tubes are coupled to the battery module stack according to an embodiment of the present disclosure.FIG.12is a view illustrating a state in which a plurality of vertical square tubes are coupled to the battery module stack ofFIG.9.FIG.15is a view illustrating a state in which a plurality of horizontal square tubes are coupled to the battery module stack ofFIG.12.

A method for manufacturing a battery pack according to an embodiment of the present disclosure sequentially performs the steps of: stacking and arranging a plurality of longitudinal square tubes300mounted on the battery module stack200in a vertical direction between the stacked battery modules210so as to be coupled integrally with the battery modules210formed in the left and right directions at the uppermost part and the lowermost part; coupling a plurality of vertical square tubes400with all of the longitudinal square tubes300respectively located on a plurality of longitudinal axes of the stacked longitudinal square tubes300in the four-direction outer periphery of the battery module stack120; and in the outside of the plurality of vertical square tubes, coupling a plurality of horizontal square tubes500with all of the parts of the vertical pipes400respectively located on a plurality of axes in the front and rear directions among the plurality of vertical square tubes400.

A state in which the plurality of longitudinal square tubes300are arranged can be confirmed inFIG.8. As shown inFIG.8, as the battery modules210are stacked upward, a plurality of vertical square tubes300may be stacked and disposed to correspond to each battery module210.

A state in which the plurality of vertical square tubes400are arranged can be confirmed throughFIG.12. As shown inFIG.12, a plurality of longitudinal square tubes400may be arranged to be connected to a plurality of longitudinal square tubes300in the vertical direction to fix the plurality of vertical square tubes400.

A state in which the plurality of horizontal square tubes500are arranged can be confirmed throughFIG.15. As shown inFIG.15, a plurality of horizontal square tubes500are arranged to be connected to a plurality of vertical square tubes400in the front and rear direction, a plurality of longitudinal square tubes300and a plurality of vertical square tubes400can be fixed.

According to an embodiment of the present disclosure, after the step of combining the plurality of horizontal square tubes500, the battery module stack200is attached to the lower case120through the bracket130as shown in FIG. The step of fixing and coupling the upper case110to the lower case120as shown inFIG.23may be further included.

The battery pack can be applied to various devices. Such a device may be applied to a vehicle such as an electric bicycle, an electric vehicle, or a hybrid vehicle, but the present disclosure is not limited thereto, and is applicable to various devices that can use a battery module, which also belongs to the scope of the present disclosure.

Although the invention has been shown and described with reference to the preferred embodiments, the scope of the present disclosure is not limited thereto, and numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of the invention described in the appended claims.

Further, these modified embodiments should not be understood individually from the technical spirit or perspective of the present disclosure.

DESCRIPTION OF REFERENCE NUMERALS

110: upper case120: lower case121: bracket connecting part122: longitudinal square tube connecting part130: bracket131: first bracket132: second bracket210: battery module200: battery module stack300: longitudinal square tube310: first longitudinal square tube311: connecting part312,313: first vertical square tube connecting part314,315: second vertical square tube connecting part317,318:1-1vertical square tube connecting part316: support part320: second longitudinal square tube321,322: second vertical square tube connecting part323: cut-out part324: support part330: third longitudinal square tube331: connecting part332,333: first vertical square tube connecting part334,335: second vertical square tube connecting part336,337:1-1vertical square tube connecting part340: fourth longitudinal square tube341,342: vertical square tube connecting part343: cut-out part400: vertical square tube410: first vertical square tube411: longitudinal square tube connecting part420: second vertical square tube421: longitudinal square tube connecting part422: horizontal square tube connecting part423: bracket connecting part500: horizontal square tube501: vertical square tube connecting part600: heat sink610: heat sink insulator610a: tongs part611: first heat sink insulator612,613: second, third heat sink insulator700: BMS701: connecting part800: BDU801: connecting part900: cooling water pipe