WO2021225204A1

WO2021225204A1 - Housing for electric vehicle battery pack

Info

Publication number: WO2021225204A1
Application number: PCT/KR2020/006343
Authority: WO
Inventors: 송대천; 남상현; 강국진
Original assignee: 에너테크인터내셔널 주식회사
Priority date: 2020-05-07
Filing date: 2020-05-14
Publication date: 2021-11-11
Also published as: KR102281771B1

Abstract

Disclosed is a housing for an electric vehicle battery pack, the housing comprising: a case main body having wall surfaces that are formed through sheet metal working; a cover for covering an opened portion of the case main body; plate-type brackets for installing modules, the plate-type brackets being coupled to side surfaces of battery modules with certain distances from the wall surfaces of the case main body; and a beam-type frame installed on the bottom of a case to reinforce the bottom of the case main body. The plate-type brackets each include at least one of: a bent portion bent from a plate surface to maintain and fix distances from the wall surfaces of the case main body; and a support portion coupled to the beam-type frame so as to support the battery module. Thus, a certain distance is provided by the bent portion between the battery module and the wall surfaces of the case main body, and at least a part of the battery module has a distance from the bottom through the coupling between the beam-type frame and the support portion.

Description

Housing for electric vehicle battery pack

The present invention relates to a battery for an electric vehicle, and an electric vehicle having a structure that can more easily combine battery modules to form an overall battery pack, can effectively respond to shock and vibration by itself, and secure mechanical strength It relates to a housing for a battery pack.

Due to the strengthening of international environmental regulations on automobile exhaust gas, the possibility of depletion of oil, and the continued high oil price, the global automobile market is turning from internal combustion engine vehicles to electric vehicles. In particular, pure electric vehicles (EVs) are emerging as an effective global greenhouse gas reduction means and a powerful alternative for a sustainable environment. Meanwhile, sales of electric vehicles (EVs) and hybrid vehicles (HEVs) are increasing significantly as consumers' preference for low-cost fuel vehicles increases due to the burden of rising fuel costs. As a result, advanced countries are strongly promoting electric vehicle supply policies.

Therefore, the capacity and efficiency of the battery, which are key components for operating an electric vehicle, are the most important factors for an electric vehicle, and the drivable distance according to the performance is a big issue. this is rising

Conventional vehicle electric vehicle batteries mainly used lead-acid batteries, but since lead-acid batteries are used as power sources for vehicles, the amount of electricity that can be accumulated compared to weight and volume, i.e., charge capacity, is low, so lithium, which can increase the charge capacity compared to weight, is a lithium battery for electric vehicles. This series of batteries is mainly used.

A battery is basically a device made to make chemical energy compatible with electrical energy, and the use of a secondary battery capable of charging and discharging together is a basic premise due to the characteristics of a vehicle.

A lithium ion battery used in an electric vehicle forms a module in which a plurality of battery cell units are closely coupled to each other in order to secure a stable capacity, and a plurality of modules are combined to form a battery pack having a sufficient capacity. In an electric vehicle battery including this module type, the overall weight is increased, so a case or housing is used to stably accommodate it and mechanically protect it, and a fairly high level of rigidity of the housing is required.

In addition, since an electric vehicle battery is exposed to vibration and shock according to the vehicle driving environment such as road surface conditions, a rigid design for the housing is required to respond to such vibration and shock, and sufficient rigidity against vibration and shock cannot be secured. In this case, deformation problems such as bending of the housing itself may occur, and defects in the fixing state of parts inside the housing, damage, and battery function problems may occur due to such deformation.

In addition, in the worst case due to an impact or accident while driving, the battery housing may be damaged, resulting in damage to the battery cell itself or other internal components, and short circuits in the power connection. In this case, the battery stores a lot of energy in a small space and Because it is an electrical and chemical object that has such energy, a problem in which the vehicle itself and its occupants are exposed to danger may occur due to a fire or explosion caused by a sudden burst of energy.

In order to solve the problems associated with the conventional electric vehicle battery housing, various techniques for selecting a housing material, a housing structure, and a manufacturing method have been proposed.

Existing battery packs for electric vehicles include a lithium-ion battery module that supplies power to the vehicle, a heating and cooling system for temperature management of the battery module, wiring to transmit electricity from the battery, and various electric devices and BMS necessary for battery control. An external case in the form of a container so that it can be contained, a bracket for fixing the battery module, a bracket for fixing the heating and cooling system, a bracket for fixing wiring, a bracket for fixing an electric device necessary for battery control, a bracket for fixing the BMS, at least the external case It comprises a cover configured to cover a part from the outside, a cover covering an electric device, and the like, a cover covering the low current fuse, and the like.

In addition, a conductive device for grounding is applied to the housing including the case and the cover to form the exterior. In addition, the bracket for fixing the battery module is heavier than other parts due to the characteristics of the module in which a large number of lithium-ion cells are combined.

Sheet metal parts use a thin steel plate due to the characteristics of the manufacturing method, and it is difficult to guarantee its own mechanical strength, so the required strength is satisfied by bending or additional welding the part that needs reinforcement. In addition, the assembly method is mainly used in the form of screw and nut fastening, and the selection of parts for strengthening the fastening force is applied.

Looking more closely at the battery case or housing, in general, a battery pack for an electric vehicle includes a battery housing and a battery cell accommodated in the battery housing. The battery housing for an electric vehicle is made by having a mount device for mounting and replacing the battery, and serves to protect the battery cell accommodated therein from the outside. In addition, sealing between the case and the cover constituting the housing is important for waterproof protection according to the external environment.

In order to solve this problem in the conventional battery housing for electric vehicles, it is composed to ensure the rigidity of the housing by press molding or die casting using a metal material of sufficient thickness, and to improve mechanical strength by adding internal members. method was used.

The method of using a steel material in the prior art has an advantageous aspect in assembling property because the material itself has excellent mechanical strength and does not pose a big problem even in the application of the welding method. However, since the material belongs to heavy metal, it is difficult to satisfy the requirements for weight reduction as a vehicle battery housing.

Another method is to use an aluminum material. In this method, the battery housing is usually made in the form of sheet metal processing, and at this time, welding in some sections is unavoidably required, and there is a problem in that the welding cost increases accordingly. In order to solve this problem, there is a technique suitable for mass production using a press mold or a die casting mold, but this also has a problem in that there is a problem of initial investment cost and there is a limitation in design flexibility.

In addition, the aluminum material itself is easier to lighten compared to the steel material, but the mechanical strength is lowered, so it is necessary to make an alloy and use it, and it is necessary to increase the mechanical thickness. High-strength plastic materials have been developed to satisfy both light weight and mechanical strength, but the high cost of the material itself and the initial mold investment cost must be considered.

That is, a housing structure with sufficient mechanical rigidity and stability typically requires a lot of rigid material to increase the weight or increase the effort and difficulty for its processing. There are issues that are difficult to protect and maintain, and these issues are generally trade-offs.

An object of the present invention is to alleviate the existing problems of a housing for an electric vehicle battery pack, and an object of the present invention is to provide a housing for an electric vehicle battery pack having a simple and light structure while having sufficient mechanical rigidity and stability.

The present invention provides a battery module including a plurality of lithium ion cells from accidents such as vibration and shock occurring in the driving environment of electric vehicles and hybrid vehicles, and mechanical rigidity of a housing for a battery pack containing control parts for power supply, etc. and to minimize deformation of the housing, such as impact, to provide user safety and to maintain stable battery power supply.

A housing for an electric vehicle battery pack of the present invention for achieving the above object,

A case body having a wall made of sheet metal processing to accommodate the battery module, a cover covering the open part of the case body, a plate-type bracket for installing modules coupled to at least two places on the side of the battery module to maintain a predetermined distance from the wall of the case body, the case body and a prosthetic frame installed on the bottom of the case to reinforce the bottom of the

The plate-shaped bracket is provided with at least one of a bent part bent from the plate surface for maintaining and fixing a distance from the case body wall, and a support part for supporting the battery module through combination with the shape-bearing frame, through the bent part, the battery module and the case It has a predetermined distance from the wall surface of the body, and at least a portion of the battery module has a gap between it and the floor through the combination of the prosthetic frame and the support part.

In the present invention, the shape retaining frame may be formed integrally by bending the bottom of the case body, or may be formed by coupling a separate U-shaped or U-shaped frame to the floor.

In the present invention, the prosthetic frame may be installed long in the width direction in the case.

In the present invention, the housing may be further provided with a frame formed over the entire length in the longitudinal direction. .

In the present invention, the case body made of sheet metal processing may be made of a steel sheet including a stainless steel material, and may be mainly formed through a sheet metal and welding process of such a steel sheet.

According to the present invention, the space between the module and the case can be secured by using a bracket for installing the module in the case, thereby providing a cushioning action in consideration of the vibration and impact in the vehicle driving environment, the possibility of an accident, etc. By improving the mechanical strength, it is possible to increase the safety and stability of the battery pack and to exclude deterioration of battery performance.

According to the present invention, by increasing the stability of the assembly structure of the battery, it is possible to reduce the occurrence of abnormal battery functions and safety risk factors, thereby improving the safety of the battery itself and the vehicle and passengers.

According to the present invention, it is possible to increase the space and weight efficiency of the battery pack while securing mechanical strength at a relatively low cost, it is possible to easily secure a space for wiring, etc., and in the case of air cooling, it is possible to secure a space for air circulation. can

1 is an exploded perspective view of a housing for a battery pack according to the present invention;

2 is a plan view, a front view, a bottom view of the housing for the battery pack shown in FIG. 1 viewed from the top, front and bottom;

3 is an exploded perspective view showing the battery module and the left bracket, the right bracket, and the rear bracket coupled to the side thereof in an exploded state;

4 is a plan view showing the configuration of the bottom surface of the housing for the battery pack shown in FIG. 1;

5 is a perspective rear view of the battery housing shown in FIG. 1 and a partially enlarged view of a part thereof;

6 is a plan view showing the module left/right bracket 61 and the module center bracket 62 together to which the case and the upper bracket of the housing for the battery pack shown in FIG. 1 are assembled;

7 is a perspective perspective view showing brackets installed inside the housing case for the battery pack shown in FIG. 1;

8 is a rear view showing the grounding portions of each of the three types of covers of the housing for the battery pack;

9 is a rear view showing the grounding part of the bracket for fixing the BMS circuit;

10 is a conceptual diagram illustrating a limit switch operation of a low current fuse cover.

Hereinafter, the present invention will be described in more detail through specific examples with reference to the drawings.

1 is an exploded perspective view of a housing for an electric vehicle battery pack constituting an embodiment of the present invention as viewed from the front upper right side.

Referring to FIG. 1, when viewed as a whole, the housing constitutes a space in the form of a rectangular parallelepiped, a body in which two high voltage battery modules are accommodated, a smaller rectangular space in front of it, and a small space forming a trapezoid when viewed from the front above. It is made by having a case 100 having a BMS installation part forming a cover and covering the open part of the case.

For convenience, the left and right directions of the front view can be considered as the longitudinal direction of the battery pack, the front-back direction as the width direction of the battery pack, and the vertical direction as the thickness direction of the battery pack.

Such a case may be formed by preparing an iron plate, cutting and bending in the form of a developed view, and welding a part of the sheet metal. At this time, the hole at each position including the bolt hole may be formed through drilling or punching.

Examples of the covers include a battery cover 101 that covers a portion in which the battery module is accommodated, a BMS cover 102 that covers the BMS and electronic components from the front wall side, and a fuse cover 103 that covers a low current fuse. The cover may be coupled by a method such as aligning the coupling hole installed in the flange or wall of the case with the coupling hole formed in the cover through a gasket or the like, and tightening coupling means such as a bolt or nut.

In addition, when viewed from the front of the battery pack, the housing is a plate-shaped bracket assembled and coupled to the left, right, and rear of the two battery modules constituting the battery pack. The right bracket 10, the left bracket 11, and the rear bracket 12 have

In the upper front of the plate body of the left bracket 11 of the battery module, there is a bent part 10c that protrudes forward from the plate body and is bent to the left, and the upper front and rear of the plate body has a bent part that protrudes upward and is bent to the right, and the battery At the upper front of the plate body of the right bracket 12 of the module, there is a bent part that protrudes forward from the plate body and is bent to the right, and the upper front and rear of the plate body has a bent part that projects upward and is bent to the left.

The rear bracket 12 has a bent portion protruding to the left and bent backward and a bent portion protruding to the right and bent rearward on the upper portions of both ends of the rear bracket 12 .

Bolt holes or fastening holes are installed in these bent portions, so that bolting can be achieved with a case, cover, or other bracket of the housing.

Below the left side of the left side bracket and below the right side of the right side bracket, there is a supporting bracket forming a separate supporting part installed by welding or the like lengthwise in the width direction. There are three fastening holes arranged in a , and one fastening hole through which the bolt can pass from the front to the rear.

The bent portions protruding upward from the upper side of the plate body of the left and right brackets and bent to the right and left are coupled to the

upper brackets

104 and 105 that are additionally installed to fix the battery module to the pack upper cover or the case wall.

In the BMS installation part of the case 100, a horizontal plate-type BMS plate 106 configured to integrate electric devices, etc., and a vertical plate-type BMS bracket 107 for mounting a BMS circuit are provided as a part of the housing. do.

Referring to FIG. 2 , as shown, the in-outlet pipe of the cooling plate should be exposed on the outer front surface of the housing, and a through hole 201 to which a rubber bushing is applied is formed so as not to be affected by vibration. In addition, depending on the battery usage environment, pressure may be generated inside the housing. For waterproof protection, airtightness must be maintained. Therefore, vent holes 202 for venting air when internal pressure is generated may be disposed in two places on the front of the housing. is configured to

3 shows a form in which a plate-shaped left bracket, a right bracket, and a rear bracket as shown in FIG. 1 are coupled to two battery modules.

Here too, the support bracket having three fastening holes 10a through which bolts pass in the vertical direction on the left side of the left side bracket and the right side of the right side bracket coupled to the battery module, and one fastening hole 10b in the horizontal direction are welded. It can be seen that they are combined.

The support bracket can be screwed to the prosthetic frame installed on the bottom surface of the case, shown in FIG. 4 .

Looking more closely, a plurality of circular-shaped emboss 404 convexly protrude upwards from the bottom of the case in the area where the battery module is accommodated, so that direct friction with the bottom surface of the module can be avoided and suppressed. In addition, in the battery module storage space inside the housing, the

shape retaining frames

400 , 401 , 402 for fixing the battery module are welded to the center and left and right sides of the bottom of the case. A hexagonal rivet-type nut 403 for strengthening bolt fastening force is assembled to these prosthetic frames.

The shape retaining frame may be installed by long welding a rectangular pipe-shaped structure in the case width direction, wherein a plurality of them are installed side by side. Instead of the shape retaining frame, it is also possible to install the reinforcing part by bending the section to form a U-shape when processing the corresponding part of the iron plate constituting the bottom of the case.

Therefore, in the state where the left bracket, the right bracket, and the rear bracket are combined with the battery module, the battery module is stored inside the case, respectively, and the retaining frame (400, 401, 402) to have the effect of fixing the lower end of the battery module to the case.

It is possible to have a similar effect when installing the BMS plate by placing the prosthetic frame 709 on the floor in the BMS installation part of the case.

Looking through the configuration as described above, the battery module having a considerable own weight can maintain a certain distance from the case wall through the bent portions of the right bracket, left bracket, and rear bracket attached to the side thereof, It can be fixed to the cover or case wall.

In addition, since the bent part is usually made by processing a sheet metal, it is light and may have the advantage that the plate body acts as a buffer like a spring in some cases against vibration and shock applied to the battery pack.

However, since this fixing is to fix the battery module in the inner space of the housing as if it were hanging, considering the weight of the battery module itself and the load that the bent part can withstand, it is not suitable for stable fixation, or the number of bent parts increases for stable fixation. Assembly and maintenance can be difficult. In this situation, the prosthetic frame installed on the bottom of the case holds the battery module together with the support (support bracket) that is coupled to the left and right brackets as if supporting it from below, so it can improve stability when fixing a heavy battery module. .

In addition, the mechanical strength of such a bracket can serve to prevent deformation of the case itself in addition to the role of supporting the battery module by reinforcing the case itself, which is made of sheet metal, like a skeleton.

Referring to FIG. 5 , at the front in which the battery module is accommodated in the case, the upper three fastening parts 502 assembled like a water cooling plate and the lower three fastening parts 501 assembled like the case are horizontally arranged in the longitudinal direction. It forms a structure in which the water cooling plate and the battery module are closely attached to each other and fixed by fastening them to the corresponding positions with fastening bolts.

Referring to FIG. 6 , at the upper left/right side of the battery module, left/right module left/right brackets 601 fixed to the housing side wall or cover are installed on the left/right side for additional strength reinforcement. The space between the two battery modules is reinforced to compensate for vibration and shock by installing a module central bracket 602 that is connected for additional reinforcement. These brackets can be assembled with the

top brackets

104 and 105 mentioned in FIG. .

Referring to FIG. 7 , there is a space in the front of the housing to accommodate the cooling plate. To prevent the cooling plate from being deformed by vibration and shock, the long cooling

plate reinforcement brackets

701 and 702 bent in an L shape are installed in the longitudinal direction. The cooling plate is stably fixed to the case by welding it to the upper and lower sides of the front of the case so that it can be accommodated.

In the position where the wiring harness inside the housing and the high voltage cable or bus bar pass, a tie part is used for easy wiring fixation. At each suitable position, a plurality of separate wiring mount brackets 703 are welded or a bent shape is created to create a mount hole. was applied. With this shape, the vibration effect of the wiring part can be excluded. In addition, in the wiring path of the inner rear part of the housing, a long angle bracket 704 bent in a V shape and having a plurality of perforated shapes was welded in the longitudinal direction to reinforce the lateral strength.

The material of the housing of the present invention is a metal material and has electrical conductivity, but plating and painting are performed to protect the external environment such as corrosion, and there is a gasket for sealing between the case and the cover, so that the housing case and the cover are electrically insulated. . For grounding and shielding, the outside of the housing must maintain electrical conductivity. For this,

conductive members

705, 706, and 707 for grounding are welded to the housing case to maintain electrical conductivity as a contact.

Referring again to FIG. 2 together with FIG. 8, as shown in FIG. 8, the battery cover, the electronic device cover, and the fuse cover are plated except for painting on the

surfaces

901, 902, and 903 at positions corresponding to the conductive members. to enable electrical conduction upon contact. In addition, a separately processed grounding bolt 204 is welded to the outside of the housing to ensure a grounding connection with the vehicle outside the battery pack.

The assembly of the housing case and the cover for the battery pack is fixed with a fastening bolt, and a hexagonal non-penetrated blind rivet nut 205 is welded to the housing case because proper fastening force and waterproof protection are required.

All electric devices of the battery pack configuration are integrated into one BMS plate 106 to facilitate assembly, and a plurality of prosthetic frames 709 that can accommodate them are welded and applied to the battery housing case.

A separate BMS bracket 107 as shown in Fig. 9 for fixing the BMS circuit is applied with a stainless steel material to guarantee strength and to maintain conductivity by removing the paint on the contact surface area 801 for shielding when fastening with the housing. . A bracket 710 for fixing the paint is also welded to the fixing part of the BMS circuit fixing bracket of the battery case.

As shown in FIG. 2 , the housing for the battery pack is provided with eight non-penetrated nuts ensuring a certain depth on the bottom surface for mounting in an electric vehicle. In order to accommodate a strong fastening force and an appropriate bolt length used in a vehicle, a separately processed blind nut 203 was welded and applied. The blind nut is embedded inside the battery pack so that it does not protrude outside while excluding interference with other parts.

On the other hand, the battery pack integrates the power supply function required for the low power of the vehicle and the related control parts are built-in. This had a problem in that the battery housing had to be disassembled when a replacement cycle occurred. In the housing of this embodiment, as shown in FIG. 10 in order to solve the ease of fuse replacement, the fuse cover 103 is separately disposed around the vehicle connector interface to ensure user convenience. In addition, in order to forcibly cut off the power supply when the fuse cover is opened, a mounting hole 1002 for installing a limit switch is applied to the battery case, and a guide pin 1001 that detects the limit switch is welded to the fuse cover. In the case, the safety of the user can be guaranteed.

In the above, the present invention has been described through limited examples, but these are only illustratively described to help the understanding of the present invention, and the present invention is not limited to these specific examples.

Accordingly, those of ordinary skill in the art to which the present invention pertains will be able to make various changes or application examples based on the present invention, and it is natural that such modifications or application examples belong to the appended claims.

Claims

A case body having a wall made of sheet metal processing to accommodate the battery module;

a cover covering the open portion of the case body;

A plate-type bracket for installing a module coupled to at least two places on the side of the battery module to maintain a predetermined distance from the wall surface of the case body;

and a shape retaining frame installed on the bottom of the case to reinforce the bottom of the case body,

The plate-shaped bracket is provided with at least one of a bent part bent from the plate surface for maintaining and fixing a distance from the case body wall surface and a support part for supporting the battery module through coupling with the shape-retaining frame,

Having a predetermined distance from the wall surface of the battery module and the case body through the bent portion,

A housing for an electric vehicle battery pack, characterized in that at least a portion of the battery module has a gap between it and the floor through the coupling of the prosthetic frame and the support part.
The method of claim 1,

The housing for an electric vehicle battery pack, characterized in that the shape-retaining frame is formed integrally by bending the bottom of the case body, or by coupling the bottom of the case body and a separate U-shaped or U-shaped frame to the bottom.
3. The method according to claim 1 or 2,

The housing for an electric vehicle battery pack, characterized in that a plurality of the prosthetic frames are installed side by side in the width direction of the case body.
3. The method according to claim 1 or 2,

The case body is a housing for an electric vehicle battery pack, characterized in that the steel plate or stainless steel plate is formed by welding and sheet metal.
3. The method according to claim 1 or 2,

The bent part is a housing for an electric vehicle battery pack, characterized in that it is fixed to the side wall or cover of the case body directly or indirectly through another bracket member.