KR20220118787A - Frame for battery module of electric vehicle having an excellent impact-resistance - Google Patents

Abstract

The present invention relates to an electric vehicle battery module frame with improved impact resistance. Specifically, the present invention relates to an electric vehicle battery module frame that can stably support and protect an electric vehicle battery module due to improved impact resistance and excellent dimensional precision and strength, can improve battery performance by stably maintaining the temperature of the electric vehicle battery module through excellent heat dissipation effect, is advantageous for weight reduction, and can reduce manufacturing costs.

Description

Frame for battery module of electric vehicle having an excellent impact-resistance

The present invention relates to an electric vehicle battery module frame with improved impact resistance. Specifically, the present invention can stably support and protect an electric vehicle battery module due to improved impact resistance and excellent dimensional precision and strength, and maintains the temperature of the electric vehicle battery module stably through excellent heat dissipation effect to improve battery performance. It relates to an electric vehicle battery module frame that can be improved, advantageous for weight reduction, and reducing manufacturing cost.

In an electric vehicle, the stability and performance of the battery are the most important factors that determine the marketability of an electric vehicle, such as the driving range. In particular, the performance of the battery is greatly affected by the ambient temperature, and in general, proper performance can be realized only when the battery is maintained at a temperature of 0 to 40°C.

However, the battery generates heat during charging or discharging (operation), which may increase the ambient temperature and deteriorate battery performance. In addition, since it is necessary to protect the battery from the surrounding shock such as an accident or the vibration of the electric vehicle itself, a frame for stably supporting and protecting the battery by mounting the battery is used.

The conventional battery module frame may be made in the form of a metal box capable of accommodating a plurality of battery cells constituting the battery module, and such a metal frame may stably protect the battery cells from external impact with high mechanical strength. It can be protected from the battery, and the heat emitted from the battery cells can be quickly dissipated out of the battery module due to its high thermal conductivity.

In general, in order for an electric vehicle to travel the same mileage as an internal combustion engine vehicle, a battery of about 360 to 400 kg is required, where the weight of the battery module frame is about 10 to 20%. Therefore, if the weight of the battery module frame can be reduced, more battery cells can be mounted, which can lead to an increase in the mileage.

Therefore, the conventional metal battery module frame is changing from a conventional iron material having a specific gravity of 7.8 g/cm3 to an aluminum material having a specific gravity of 2.7 g/cm3 to a lightweight metal in order to reduce the weight, but the aluminum material generally requires molding processing. It is difficult to produce low productivity, and since it is manufactured through an extrusion process, there is a problem in that the processing cost is increased due to additional processes such as separate chamfering, that is, inclined or rounded the edge of a member having each cross-section.

In particular, the electric vehicle battery module frame must form a precisely standardized space for accommodating a predetermined number of battery cells in order to stably protect the battery module from the impact caused by the vibration of the electric vehicle, the separation distance between the battery cells and the battery pack It is necessary to ensure very precise dimensional stability such as a position in which it is placed, for example, a tolerance of ±0.3 mm, but a battery module frame made of a metal material, which is difficult to form and process in the prior art, has a problem in that it is difficult to sufficiently secure such dimensional accuracy.

Recently, there is a trend to reduce the weight by applying a plastic material lighter than an aluminum material, but in general, the strength and thermal conductivity of plastic is much smaller than that of a metal material, so it has a problem of lowering impact resistance and heat dissipation properties. Alternatively, additives capable of partially improving heat dissipation performance are filled and used, but these materials are expensive and have insufficient impact resistance and heat dissipation performance compared to conventional metal materials.

Therefore, it is possible to stably support and protect an electric vehicle battery module due to its improved impact resistance and excellent dimensional accuracy and strength, and to improve battery performance by stably maintaining the temperature of the electric vehicle battery module through excellent heat dissipation effect. However, there is an urgent need for an electric vehicle battery module frame that is advantageous for weight reduction and can reduce manufacturing costs.

An object of the present invention is to provide an electric vehicle battery module frame capable of stably supporting and protecting an electric vehicle battery module by having excellent impact resistance and excellent dimensional accuracy and strength.

Another object of the present invention is to provide an electric vehicle battery module frame capable of improving battery performance by stably maintaining the temperature of an electric vehicle battery module through an excellent heat dissipation effect.

Furthermore, an object of the present invention is to provide an electric vehicle battery module frame that is advantageous in weight reduction and can reduce manufacturing costs.

In order to solve the above problems, the present invention,

An electric vehicle battery module frame, comprising: an upper housing having an open lower surface and having an empty space in which a battery module can be mounted; and a lower plate coupled to the open lower surface of the upper housing, the upper housing comprising: made of a plastic material, the lower plate is made of a metal material or a thermally conductive plastic material, and one or more ribs protruding from the surface are provided on at least one surface of the plastic material surface of the upper housing, The rib provides an electric vehicle battery module frame in which an elastic modulus ratio (E _o) defined by Equation 1 below satisfies 1 to 50.

[Equation 1]

E _o =E _R /E _P

In Equation 1 above,

E _R is the modulus of elasticity of the rib (0.2% offset),

E _P is the elastic modulus (0.2% offset) of the upper housing 110 .

Here, the total volume of the rib (rib) provides an electric vehicle battery module frame, characterized in that 5 to 90% based on the total volume of the upper housing.

In addition, a plurality of ribs are provided, and a distance between two adjacent ribs is 1/100 or more and less than 1/2 of the length of the surface of the upper housing provided with the ribs, providing an electric vehicle battery module frame do.

On the other hand, at least one surface of the surface made of the plastic material of the upper housing provides an electric vehicle battery module frame, characterized in that it has an embossed structure locally protruding outward or an intaglio structure locally depressed inward.

Here, the distance (B) between both ends of the position protruding outward in the embossed structure and the distance (B) between both ends of the position recessed inward in the engraved structure is the embossed structure or the intaglio structure provided with It provides an electric vehicle battery module frame, characterized in that it is 1/1000 or more and less than 1/2 of the total length of a surface made of a plastic material.

In addition, the protrusion angle (θ) of the embossed structure and the recessed angle (θ) of the intaglio structure are 5 to 90°, it provides an electric vehicle battery module frame.

And, it provides an electric vehicle battery module frame, characterized in that the reinforcing material is embedded in one or more of the surfaces made of the plastic material of the upper housing or the ribs provided on the surface made of the plastic material.

Here, the thickness of the reinforcing material is 200 μm or more, and the elastic modulus ratio (Eo) of the reinforcing material according to Equation 2 below is 1.1 to 50, and provides an electric vehicle battery module frame.

[Equation 2]

E _o =E _S /E _P

In Equation 2 above,

E _S is the elastic modulus (0.2% offset) of the reinforcement,

E _P is the modulus of elasticity (0.2% offset) of the upper housing.

On the other hand, it provides an electric vehicle battery module frame, characterized in that the upper housing and the lower plate is coupled by insert injection molding or structural adhesive.

In addition, the surface where the lower plate is coupled to the upper housing is at least partially curved or a notch or hole is formed, and the length when the curved surface is flattened is 10% or more compared to the length between the both ends before blooming It provides a large, electric vehicle battery module frame.

It provides an electric vehicle battery module frame, characterized in that a primer layer composed of any one of an epoxy-based, an acrylic-based or a urethane-based primer layer is applied to the bonding surface of the lower plate and the upper lower jig to increase adhesion.

Here, the surface on which the lower plate is coupled to the upper housing has a surface roughness (Ra) of 6 or more, a surface roughness (Rmax) of 25 or more, and a surface roughness (Rz) of 25 or more. to provide.

In addition, the upper housing has a tensile strength of 30 to 500 MPa according to the standard ASTM D638, a flexural strength of 50 to 400 MPa according to the standard ASTM D790, and a burning time according to the standard UL-94 V test of 60 seconds or less, The thermal deformation temperature according to the standard ASTM D648 is 50 to 300 ° C, the Izod impact strength according to the standard ASTM D256 is 1 kJ / m 2 or more, and the shrinkage according to the standard ASTM D955 is 0.03 to 3%, characterized in that , provides an electric vehicle battery module frame.

In addition, the plastic material forming the upper housing is made of polyamide (PA), modified polyphenylene oxide (mPPO), polybutyl terephthalate (PBT), polyethyl terephthalate (PET), and polycarbonate (PC). It provides an electric vehicle battery module frame comprising one or more engineering plastics selected from the group and one or more reinforcing additives selected from the group consisting of glass fibers, carbon fibers, aramid fibers, carbon nanotubes and graphene.

Here, the content of the reinforcing additive provides an electric vehicle battery module frame, characterized in that 5 to 100 parts by weight based on 100 parts by weight of the engineering plastic.

On the other hand, it provides an electric vehicle battery module frame, characterized in that the cooling plate is formed a refrigerant flow path through the lower portion of the lower plate is disposed.

Here, the ratio of the plane cross-sectional area of the refrigerant passage to the total planar cross-sectional area measured in the cross-section in which the plane cross-sectional area of the refrigerant passage is maximized among the cross-sections of the cooling plate is 50% or more.

The electric vehicle battery module frame according to the present invention is made of a specific plastic material and has improved impact resistance and improved dimensional accuracy and It has excellent strength to stably support and protect the electric vehicle battery module, and it has an excellent effect of improving the battery performance by stably maintaining the temperature of the electric vehicle battery module through excellent heat dissipation effect.

In addition, the electric vehicle battery module frame according to the present invention exhibits an excellent effect in that it is advantageous to light weight and the manufacturing cost can be reduced through a specific plastic material.

1 schematically shows an exploded perspective view of an embodiment of an electric vehicle battery module frame according to the present invention.
FIG. 2 schematically illustrates a perspective view of the electric vehicle battery module frame shown in FIG. 1 .
FIG. 3 schematically illustrates an embodiment in which a cooling plate is disposed under the frame of the electric vehicle battery module shown in FIG. 2 .

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art. Like reference numbers refer to like elements throughout.

1 schematically illustrates an exploded perspective view of an embodiment of an electric vehicle battery module frame according to the present invention, and FIG. 2 schematically illustrates a perspective view of the electric vehicle battery module frame illustrated in FIG. 1 .

As shown in FIGS. 1 and 2 , the electric vehicle battery module frame 100 according to the present invention has an open lower surface and an empty space in which a battery module including a plurality of battery cells can be mounted. It may include a 'C'-shaped upper housing 110 having an open front and back so that the battery module can be inserted, and a lower plate 120 coupled to the open lower surface of the upper housing 110 . .

The upper housing 110 may be made of a plastic material. Since the upper housing 110 is made of a plastic material, unlike a conventional metal frame, injection molding is possible, so dimensional accuracy is greatly improved, and thus, through a closer adhesion between the inner wall of the upper housing 110 and the battery module By minimizing the empty space between them, it is possible to more stably support and protect the battery module even when the electric vehicle vibrates, and it is possible to prevent the heat dissipation effect from being deteriorated by the empty space.

Specifically, the plastic material is polyamide (PA6, PA66), modified polyphenylene oxide (mPPO), polybutyl terephthalate (PBT), polyethyl terephthalate (PET), engineering plastics such as polycarbonate (PC) , Preferably, a reinforcing additive such as glass fiber, carbon fiber, aramid fiber, carbon nanotube, graphene, etc., preferably glass fiber, may be added to the engineering plastic of polyamide (PA).

Here, the content of the reinforcing additive may be 5 to 150 parts by weight, preferably 20 to 120 parts by weight, based on 100 parts by weight of the engineering plastic. When the content of the reinforcing additive is less than 5 parts by weight, the desired mechanical properties such as tensile strength and flexural strength of the upper housing 110 cannot be satisfied, whereas when it exceeds 150 parts by weight, to manufacture the upper housing 110 During injection for injection, productivity is reduced due to severe abrasion of screws and molds of the injection machine, the weight of the upper housing 110 is increased due to the increase in specific gravity of the plastic material, and some mechanical properties such as impact strength are lowered. can

The plastic material has excellent mechanical strength for protecting the battery module from external impact, for example, the tensile strength measured under a load of 20 kN at a rate of 5 mm/min according to the standard ASTM D638 of 30 to 500 MPa, preferably is 50 to 400 MPa, more preferably 70 to 300 MPa, and the flexural strength measured by a 3-point flexural test under a load of 20 kN at a speed of 5 mm/min according to standard ASTM D790 is 50 to 500 MPa, preferably preferably 80 to 400 MPa, more preferably 130 to 350 MPa.

Here, if the tensile strength of the plastic material is less than 30 MPa, the minimum mechanical properties for protecting the battery module from external impact may not be satisfied, whereas if it exceeds 500 MPa, injection processability is lowered by an excessive amount of additives, and Manufacturing costs may increase unnecessarily.

In addition, if the flexural strength of the plastic material is less than 50 MPa, it may be difficult to withstand mechanical stress due to thermal expansion of the battery module, whereas if it exceeds 500 MPa, injection processability is reduced due to excessive additives and manufacturing cost is increased unnecessarily. can

On the other hand, the plastic material has excellent flame retardancy that can withstand fire, for example, a flame of 20 mm in length according to the standard UL-94 V test for 10 seconds, and then the combustion time is 60 seconds or less, preferably the combustion time This is 30 seconds or less, and more preferably, the combustion time after secondary flame contact for an additional 10 seconds may be 90 seconds or less, preferably the combustion time may be 60 seconds or less, and a high heat deflection temperature that can withstand the heat emitted from the battery module , For example, the thermal deformation temperature, which is the temperature when the specimen sags 0.254 mm while heating the oil at a rate of 120 ° C / hr after preheating for 5 minutes by immersing the specimen in oil according to the standard ASTM D648, is 50 to 300 ° C., preferably Preferably it may be 80 to 270 ℃, more preferably 100 to 250 ℃.

Here, when the thermal deformation temperature of the plastic material is less than 50°C, deformation such as distortion of the upper housing 110 may occur due to heat generated in the battery module, whereas when it exceeds 300°C, the melting point is too high for compounding and Injection processability may be greatly reduced and manufacturing cost may increase unnecessarily.

In addition, the plastic material has excellent low-temperature impact properties that can be used even in a low-temperature environment, for example, Izod, which is measured when the specimen is cut by striking with a hammer after leaving it for at least 30 minutes in a chamber at -30°C according to standard ASTM D256 (Izod) the impact strength may be 1 kJ/m 2 or more, preferably 3 kJ/m 2 or more, more preferably 5 kJ/m 2 or more.

Here, when the Izod impact strength of the plastic material is less than 1 kJ/m2, the battery module cannot be properly protected, such as the battery module being damaged by a crash accident in a low-temperature environment such as winter. On the other hand, the higher the low-temperature impact strength, the better, but it is preferable to maintain an appropriate level in trade-off with tensile strength, flexural strength, flame retardancy, and the like.

In addition, the plastic material has a shrinkage rate showing excellent dimensional accuracy, for example, the shrinkage rate measured by injection into a mold at a temperature of 23±2° C. and a humidity of 50±5% according to the standard ASTM D955 and separating after 24±0.5 hours is 0.03 to 3%, preferably 0.05 to 2%, more preferably 0.1 to 1%, and when the shrinkage ratio is less than 0.03%, properties such as injection productivity are deteriorated due to an excessive amount of additive, whereas when it is more than 3% It is difficult to satisfy the dimensional accuracy of ±0.3 mm.

The upper housing 110 may be formed in a U-shape with the front and rear sides open so that the battery module can be inserted, but the front and back surfaces are made of the same plastic material as the upper housing 110 . can cover

The upper housing 110 may be combined with a lower plate 120 made of a material different from that of the upper housing 110 , and the upper housing 110 and the lower plate 120 are formed by insert injection molding or a structural adhesive. can be combined.

That is, in the case of insert injection molding, the lower plate 120 is prepared in advance and inserted into the injection mold, and then the plastic material of the upper housing 110 is melted/injected into the mold and injected into a box-shaped structure. can make In this case, in order to increase the adhesive force between different materials, the bonding area may be increased by forming irregularities or the like on the bonding surface or by roughening the surface roughness of the bonding surface.

In the case of using a structural adhesive, the lower plate 120 and the upper housing 110 may be manufactured and adhered with a structural adhesive to form a box-shaped structure. At this time, an epoxy-based, acrylic-based or urethane-based primer may be applied to the adhesive surface in order to increase adhesion.

The lower plate 120 may be made of a metal material having high thermal conductivity, such as aluminum, copper, iron, etc., but polyamide (PA), modified polyphenylene oxide (mPPO), polybutyl terephthalate (PBT), polyethyl Engineering plastics such as terephthalate (PET), polycarbonate (PC), preferably polyamide (PA), carbon fibers, carbon nanotubes, graphene, aluminum nitride, boron nitride ), may be made of a thermally conductive plastic material filled with a thermally conductive additive including a metal powder such as silicon carbide or aluminum.

The thermal conductivity of the lower plate 120 is 0.5 to 1,000 W/m·K, preferably 1 to 600 W when made of a metal material or a plastic material in order to secure the heat dissipation characteristics of the battery module frame. /m·K, more preferably 2 to 300 W/m·K may be made of a material.

When the thermal conductivity of the material forming the lower plate 120 is less than 0.5 W/m·K, the heat dissipation property is insufficient and degradation of the battery module may be induced, whereas when it exceeds 1,000 W/m·K, excessive The addition of the thermally conductive additive may cause a problem in that processability is lowered and manufacturing cost is unnecessarily increased.

Specifically, when the lower plate 120 is formed of a plastic material, the content of the thermal conductive additive may be 5 to 150 parts by weight, preferably 20 to 120 parts by weight, based on 100 parts by weight of the engineering plastic. Here, when the content of the thermal conductivity additive is less than 5 parts by weight, it is difficult to implement thermal conductivity of 0.5 W/m·K or more, and when it is more than 150 parts by weight, the specific gravity of the plastic material exceeds 2 g/cm 3 , so the battery module frame weight reduction may be insufficient.

The surface to which the lower plate 120 is coupled to the upper housing 110 is at least partially curved, which is not flat, or a state in which a notch or hole is formed is suitable, for example, the curved surface is flattened. The length in the case of blooming may be 10% or more, preferably 20% or more, more preferably 30% or more compared to the length between both ends before blooming. This is to maximize the contact area where the lower plate 120 and the upper housing 110 are coupled so that they can be more firmly adhered and coupled.

Specifically, the surface roughness (Ra) representing the centerline surface roughness of the joint surface of the protrusion of the lower plate 120 is 6 or more, preferably 25 or more, and the surface roughness (Rmax) representing the maximum height of the concave-convex structure is 25S or more , preferably 100S or more, the 10-point average roughness (Rz) may be 25Z or more, preferably 100Z or more.

Meanwhile, as shown in FIG. 2A , one or more ribs 111 protruding from the surface may be provided on the upper surface, the lower surface, or both of one or more of the plastic surfaces of the upper housing 110 . and the cross-sectional shape of the rib 111 may be a polygonal structure such as a triangle, a square, a pentagon, or a hexagon, or a circular structure such as a circle, an ellipse, or a semicircle, and the rib 111 is provided with the rib 111 It may be formed to extend in the longitudinal direction of the surface.

Here, the total volume of the ribs 111 may be 5 to 90%, preferably 10 to 70%, based on the total volume of all plastic surfaces forming the upper housing 110 . If the total volume of the ribs 111 is less than 5%, the impact resistance of the upper housing 110 may be insufficient, whereas if it exceeds 90%, there may be a problem in that the manufacturing cost of the battery module frame is unnecessarily increased. .

In addition, when a plurality of ribs 111 are provided, a distance between two adjacent ribs 111 is 1/100 or more and less than 1/2 of the length of the surface of the upper housing 110 provided with the ribs 111 . , preferably 1/50 or more and 1/3 or less. When the distance between the two adjacent ribs 111 exceeds the standard, sufficient impact resistance cannot be implemented, whereas when the distance is less than the standard, the manufacturing cost of the battery module frame is unnecessarily increased according to an increase in material cost may occur.

In particular, the rib 111 may be made of a plastic material that is the same as the plastic material forming the upper housing 110 or has a resin added to the plastic material and a different type and content of the reinforcing additive, whereby the following Equation 1 The elastic modulus ratio (E _o) defined as may be 1 to 50, preferably 1 to 30.

[Equation 1]

E _o =E _R /E _P

In Equation 1 above,

E _R is the modulus of elasticity (0.2% offset) of the rib 111,

E _P is the elastic modulus (0.2% offset) of the upper housing 110 .

If the elastic modulus ratio (E _o ) of the rib 111 is less than 1, the impact resistance of the battery module frame may be insufficient, whereas if it exceeds 50, the manufacturing cost of the battery module frame according to the increase in the material cost of the rib 111 This may increase unnecessarily.

On the other hand, at least one plastic surface forming the upper housing 110 or a reinforcing material such as a metal mesh, a metal plate, a metal wire, and a plastic having high impact properties in the inside of the rib 111 provided on the plastic surface may be further embedded. Here, the metal in the metal mesh, metal plate, or metal wire may include iron, stainless steel, aluminum, copper, or the like.

In addition, the plastic having the high impact properties is polyamide (PA), polycarbonate (PC), polyethylene ethylene ketone (PEEK), polyethylene terephthalate (PET) / polybutylene terephthalate (PBT), modified polyphenylene A fiber-reinforced plastic material including reinforcing fibers such as glass fibers, carbon fibers, basalt fibers, and aramid fibers in a resin such as oxide (mPPO) and polyphenylene sulfide may be included.

In addition, the thickness of the reinforcing material is suitable for 200 μm or more, and when the thickness of the reinforcing material is less than 200 μm, it is difficult to secure sufficient impact resistance, and the upper housing 110 is bent or deformed by the pressure of the plastic material during injection molding. may not be suitable.

On the other hand, the elastic modulus ratio (Eo) according to Equation 2 below of the reinforcing material may be 1.1 to 50, preferably 1.5 to 30.

[Equation 2]

E _o =E _S /E _P

In Equation 2 above,

E _S is the modulus of elasticity of the reinforcement (0.2% offset),

E _P is the elastic modulus (0.2% offset) of the upper housing 110 .

If the elastic modulus ratio (E _o ) of the reinforcing material is less than 1.1, the impact resistance of the battery module frame may be insufficient, whereas if it exceeds 50, the manufacturing cost of the battery module frame may increase unnecessarily due to an increase in material cost.

As shown in FIGS. 2B and 2C , one or more plastic surfaces of the upper housing 110 may be formed of the embossed structure 112 of FIG. 2B or the embossed structure 113 of FIG. 2C . That is, at least one plastic surface of the upper housing 110 has a structure 112 that protrudes outward locally as shown in FIG. 2B , or a structure that is locally depressed inward as shown in FIG. 2C . (113) can have.

At least one plastic surface of the upper housing 110 through the embossed structure 112 or the engraved structure 113 buffers external shock, and the shock is transmitted to the battery cell mounted inside the upper housing 110 can be prevented or minimized.

The embossed structure 112 is the distance (B) between both ends of the protruding position to the outside, and the intaglio structure 113 is the distance (B) between both ends of the protruding position to the inside is the embossed structure ( 112) or 1/1000 or more and less than 1/2 of the total length of the plastic surface provided with the intaglio structure 113, preferably 1/500 or more and 1/3 or less. In addition, the protruding angle θ of the embossed structure 112 and the recessed angle θ of the intaglio structure 113 may be 5 to 90°, preferably 10 to 45°.

Here, when the distance (B) or the angle (θ) is less than the standard, the impact resistance of the battery module frame may be insufficient, whereas when the distance (B) or the angle (θ) is more than the standard, the upper housing ( 110), there is a problem in that the manufacturing cost of the battery module frame is unnecessarily increased as the material cost increases.

Regarding the heat dissipation characteristics of the battery module frame according to the present invention, the thermal conductivity ratio (K _o ) defined by Equation 3 below may be 3 to 1,000, preferably 5 to 600.

[Equation 3]

K _o =K _R /K _L

In Equation 3 above,

K _R is the thermal conductivity of the lower plate 120,

K _L is the thermal conductivity of the upper housing 110 .

Here, when the thermal conductivity ratio (K _o ) is less than 3, the heat dissipation characteristics of the battery module frame may be insufficient, whereas if it exceeds 1,000, the manufacturing cost of the battery module frame may be excessively increased.

FIG. 3 schematically illustrates an embodiment in which a cooling plate is disposed under the frame of the electric vehicle battery module shown in FIG. 2 . As shown in FIG. 3 , a cooling plate 300 having a refrigerant flow path 310 through which a refrigerant such as cooling water may flow may be additionally disposed below the lower plate 120 .

The cooling plate 300 has a refrigerant passage 310 through which a refrigerant such as cooling water can flow therein, and may be made of a metal material such as aluminum. The lower plate 120 is made of a material having a higher thermal conductivity than the upper housing 110, so that most of the heat energy from the battery module is quickly absorbed and transferred to the cooling plate 300, thereby dissipating heat. have.

Specifically, the ratio of the plane cross-sectional area of the refrigerant passage 310 to the total cross-sectional area of the refrigerant passage 310 measured in the cross-section at which the plane cross-sectional area of the refrigerant passage 310 is maximized among the cross-sections of the cooling plate 300 is about 50% or more, preferably may be about 70% or more, and accordingly, the heat dissipation ratio, that is, the ratio of the heating value of the cooling plate 300 to the total heating value of the battery module frame may be 70% or more, preferably 80% or more, and the cross-sectional ratio is 50 % or when the heat dissipation ratio is less than 70%, the rapid heat energy absorption of the lower plate 300 and thus heat dissipation characteristics may be insufficient.

[Example]

1. Impact resistance evaluation by ribs

The battery module frames of Examples 1 to 4 and Comparative Examples 2 and 3 including an upper housing made of a plastic material and a lower plate made of an aluminum material and provided with a rib having the configuration shown in Table 1 below and made of only aluminum When an impact of 5J was applied to the battery module frame of Comparative Example 1, the degree of deformation of the battery module frame was analyzed using a simulation program Ls-Dyna.

division Elastic modulus ratio (Eo) Volume ratio (%) length ratio Maximum deformation (mm) Economics Example 1 5 20 0.25 7.03 0.68 Example 2 10 20 0.25 6.5 0.76 Example 3 30 30 0.25 6.02 0.92 Example 4 30 80 0.25 5.34 1.18 Comparative Example 1 - - 6.1 One Comparative Example 2 0.8 50 0.25 7.44 0.84 Comparative Example 3 10 20 0.5 7.3 0.73

- Volume ratio = total volume of ribs/total volume of all plastic faces*100

- Length ratio = distance between adjacent ribs/length of plastic face with ribs

- Economical: Manufacturing cost based on the manufacturing cost of Comparative Example 1

As shown in Table 1, the battery module frames of Examples 1 to 4, in which the elastic modulus ratio (Eo), volume ratio (%), and length ratio of the ribs were appropriately adjusted, are excellent in both impact resistance and economy in a well-balanced manner. Confirmed. On the other hand, the battery module frame of Comparative Example 1 in which the ribs are not provided has insufficient impact resistance compared to the manufacturing cost, and the batteries of Comparative Example 2 and Comparative Example 3 in which the ribs are provided but the elastic modulus ratio (Eo) is below the standard and the length ratio exceeds the standard It was confirmed that the module frame had significantly lowered impact resistance. The battery module frame of Comparative Example 1 is made of only aluminum material, and thus has good impact resistance and manufacturing cost, but has a problem in applying it to an electric vehicle because of its heavy weight.

2. Impact resistance evaluation by reinforcing materials

Simulation program Ls- to simulate the degree of deformation of the battery module frame when an impact of 5J is applied to the battery module frame including the upper housing made of plastic material and the lower plate made of aluminum material with the reinforcement of the configuration shown in Table 2 below. It was analyzed using Dyna.

division Elastic modulus ratio (Eo) Thickness (mm) type Maximum deformation (mm) Example 5 3 0.5 Woven Fiber Reinforced Plastics (PA/GF) 7.0 Example 6 3 One Woven Fiber Reinforced Plastics (PA/GF) 6.6 Example 7 5 One Fiber Reinforced Plastics (PA/CF) 6.2 Example 8 13 One steel plate 6.7 Example 9 15 2 steel plate 6.5 Comparative Example 4 15 0.15 steel plate 8.3

As shown in Table 2, the battery module frames of Examples 5 to 9, in which the type of reinforcing material, the elastic modulus ratio (Eo) and the thickness were appropriately adjusted, were confirmed to have excellent impact resistance, while the thickness of the reinforcing material was less than the standard. It was confirmed that the battery module frame of Comparative Example 4 had significantly lowered impact resistance.

3. Impact resistance evaluation by embossed structure

Simulation program Ls for the degree of deformation of the battery module frame when an impact of 5J is applied to the battery module frame including the upper housing made of plastic material and the lower plate made of aluminum material with the embossed structure shown in Table 3 below. -Analyzed using Dyna.

division Protrusion angle (θ) length ratio Maximum deformation (mm) Example 10 20 1/20 6.8 Example 11 20 1/50 6.3 Example 12 30 1/20 6.4 Example 13 50 1/50 6.03 Example 14 8 1/20 9.3 Comparative Example 5 30 1/2 11.3

- Length ratio = length of protrusion (B) / length of plastic side

As shown in Table 3, the battery module frames of Examples 10 to 14, in which the protrusion angle and length ratio of the embossed structure were appropriately adjusted, were confirmed to have excellent impact resistance, while the length ratio of the embossed structure was less than the standard of Comparative Example 5 It was confirmed that the battery module frame had significantly lowered impact resistance.

4. Evaluation of heat dissipation characteristics according to lower plate thermal conductivity

The battery module frame of Examples 15 to 18 and Comparative Example 2 including the upper housing made of a plastic material and the lower plate of the configuration shown in Table 4 below and the battery module frame of Comparative Example 1 made of only aluminum, the battery cells inside When mounting and applying power to the battery cells, the heat dissipation characteristics of the lower plate were evaluated.

division Thermal conductivity ratio (K _o ) lower plate
Temperature (℃) Upper housing temperature (°C) Bottom heat dissipation ratio (%) Example 15 3 38.4 39.4 76.5 Example 16 5 38.2 38.9 77.2 Example 17 20 37.9 38.3 78.1 Example 18 500 36.8 37.3 79.2 Comparative Example 1 36.5 37.1 79.5 Comparative Example 2 One 38.7 41.4 73.5

As shown in Table 4, it was confirmed that the battery module frames of Examples 15 to 18, in which the thermal conductivity ratio of the lower plate was appropriately adjusted, realized sufficient heat dissipation characteristics. However, in the battery module frame of Comparative Example 2 in which the thermal conductivity ratio of the lower plate was less than the standard, it was confirmed that the lower plate did not implement sufficient heat dissipation characteristics. On the other hand, the battery module frame of Comparative Example 1 made of only an aluminum material has excellent heat dissipation characteristics, but is not suitable for use in an electric vehicle because of its heavy weight.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all of them should be considered to be included in the technical scope of the present invention.

110: upper housing 120: lower plate
200: battery module 300: cooling plate
310: refrigerant flow path

Claims (16)

An electric vehicle battery module frame comprising:
An upper housing having an open lower surface and an empty space in which a battery module can be mounted, and a lower plate coupled to the open lower surface of the upper housing,
The upper housing is made of a plastic material,
The lower plate is made of a metal material or a thermally conductive plastic material,
One or more ribs protruding from the surface are provided on one or more surfaces of the surfaces made of a plastic material of the upper housing,
The rib (rib) has an elastic modulus ratio (E _o) defined by Equation 1 below satisfies 1 to 50, an electric vehicle battery module frame.
[Equation 1]
E _o =E _R /E _P
In Equation 1 above,
E _R is the modulus of elasticity of the rib (0.2% offset),
E _P is the elastic modulus (0.2% offset) of the upper housing 110 . According to claim 1,
The electric vehicle battery module frame, characterized in that the total volume of the ribs is 5 to 90% based on the total volume of the upper housing. 3. The method of claim 2,
The electric vehicle battery module frame, characterized in that the plurality of ribs are provided, and the distance between the two adjacent ribs is 1/100 or more and less than 1/2 of the length of the surface of the upper housing provided with the ribs. 4. The method according to any one of claims 1 to 3,
At least one surface of the surface made of the plastic material of the upper housing has an embossed structure locally protruding outward or an intaglio structure locally depressed inward, The electric vehicle battery module frame. 5. The method of claim 4,
The distance (B) between both ends of the outwardly protruding position in the embossed structure and the distance (B) between the both ends of the inwardly recessed position in the engraved structure are the embossed structure or the plastic material provided with the intaglio structure. Electric vehicle battery module frame, characterized in that less than 1/2 of 1/1000 or more of the total length of the surface made of. 6. The method of claim 5,
An electric vehicle battery module frame, characterized in that the protrusion angle (θ) of the embossed structure and the recessed angle (θ) of the intaglio structure are 5 to 90°. 4. The method according to any one of claims 1 to 3,
An electric vehicle battery module frame, characterized in that a reinforcing material is embedded in one or more surfaces of the upper housing made of a plastic material or a rib provided on a surface made of the plastic material. 8. The method of claim 7,
The thickness of the reinforcing material is 200 μm or more,
An electric vehicle battery module frame, characterized in that the elastic modulus ratio (Eo) according to Equation 2 below of the reinforcement material is 1.1 to 50.
[Equation 2]
E _o =E _S /E _P
In Equation 2 above,
E _S is the elastic modulus (0.2% offset) of the reinforcement,
E _P is the modulus of elasticity (0.2% offset) of the upper housing. 4. The method according to any one of claims 1 to 3,
The electric vehicle battery module frame, characterized in that the upper housing and the lower plate are bonded by insert injection molding or a structural adhesive and a primer. 4. The method according to any one of claims 1 to 3,
The surface where the lower plate is coupled to the upper housing is at least partially curved or a notch or hole is formed, and the length when the curved surface is flattened is 10% or more greater than the length between the two ends before blooming Characterized in the electric vehicle battery module frame. 11. The method of claim 10,
The surface where the lower plate is coupled to the upper housing has a surface roughness (Ra) of 6 or more, a surface roughness (Rmax) of 25 or more, and a surface roughness (Rz) of 25 or more. 4. The method according to any one of claims 1 to 3,
The upper housing has a tensile strength of 30 to 500 MPa according to the standard ASTM D638, a flexural strength of 50 to 400 MPa according to the standard ASTM D790, and a burning time according to the standard UL-94 V test of 60 seconds or less, and the standard ASTM Electric vehicle, characterized in that the thermal deformation temperature according to D648 is 50 to 300 ° C, the Izod impact strength according to the standard ASTM D256 is 1 kJ / m 2 or more, and the shrinkage according to the standard ASTM D955 is 0.03 to 3% battery module frame. 4. The method according to any one of claims 1 to 3,
The plastic material forming the upper housing is selected from the group consisting of polyamide (PA), modified polyphenylene oxide (mPPO), polybutyl terephthalate (PBT), polyethyl terephthalate (PET) and polycarbonate (PC). An electric vehicle battery module frame comprising one or more selected engineering plastics and one or more reinforcing additives selected from the group consisting of glass fibers, carbon fibers, aramid fibers, carbon nanotubes and graphene. 14. The method of claim 13,
An electric vehicle battery module frame, characterized in that the content of the reinforcing additive is 5 to 100 parts by weight based on 100 parts by weight of the engineering plastic. 4. The method according to any one of claims 1 to 3,
An electric vehicle battery module frame, characterized in that a cooling plate having a refrigerant flow path through which the refrigerant flows is disposed under the lower plate. 16. The method of claim 15,
The electric vehicle battery module frame, characterized in that the ratio of the plane cross-sectional area of the refrigerant passage to the total planar cross-sectional area measured in the cross-section in which the plane cross-sectional area of the refrigerant passage is maximized among the cross-sections of the cooling plate is 50% or more.

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