KR20140142770A - Middle or Large-sized Battery Pack Having Efficient Cooling Structure - Google Patents

Abstract

The present invention provides a middle/large-sized battery pack having an efficient cooling structure, which includes a module assembly provided with a plurality of battery modules which a plurality of battery cells or unit modules as a unit cell are embedded therein and are attached closely to each other, are arranged; a cooling plate attached closely to an outer surface of a thermal pad installed on top and bottom surfaces of the module assembly in order to radiate heat of the module assembly through heat conduction; a module assembly cover installed on a periphery surface of the cooling plate between the battery modules in order to prevent gas generated from an inside of the module assembly and coolant existing at an outside of the module assembly from being mixed with each other; a package cover surrounding the periphery surface of the module assembly in state that the cooling plate is exposed and having one side provided with an outlet for exhausting gas; and a gas exhausting member installed on the module assembly to collect the gas generated from the inside of the battery module to exhaust the gas through the outlet.

Description

[MEANS FOR SOLVING PROBLEMS] A middle- or large-sized battery pack having an efficient cooling structure (Medium or Large-sized Battery Pack Having Efficient Cooling Structure)

The present invention relates to a middle- or large-sized battery pack having an efficient cooling structure, and more particularly to a module assembly in which a plurality of battery modules having a structure in which a plurality of battery cells or unit modules are built as unit cells are arranged in close contact with each other A thermal pad mounted on an upper surface or a lower surface of the module assembly for dissipating heat of the module assembly due to heat conduction and a cooling plate closely attached to an outer surface of the heat dissipation pad; A module assembly cover mounted on the outer circumferential surface of the cooling plate between the battery modules in order to prevent the generated gas from interfering with the refrigerant present outside the module assembly and an outer surface of the module assembly with the cooling plate exposed As a wrapping structure, a packer having a discharge port for discharging gas on one side And to a middle- or large-sized battery pack characterized in that includes a gas vent to be mounted on the module assembly so that by collecting the gas issuing from the interior of the battery module discharged to the discharge port.

The rechargeable battery is also attracting attention as a power source for electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are proposed as solutions for the air pollution of conventional gasoline vehicles and diesel vehicles using fossil fuels. [0003] In the middle- or large-sized devices such as automobiles, a middle- or large-sized battery module in which a plurality of battery cells are electrically connected is used due to the necessity of a high output large capacity.

Since the middle- or large-sized battery module is preferably manufactured in a small size and weight, a prismatic battery, a pouch-shaped battery, and the like, which can be charged with a high degree of integration and have a small weight to capacity ratio, are mainly used as the battery cells of the middle- or large-sized battery modules. Particularly, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a great deal of attention due to its advantages such as a small weight and a low manufacturing cost.

However, a large amount of heat is generated in the secondary battery during the charging / discharging process. If the heat of the battery cell generated during the charging / discharging process can not be efficiently removed, heat accumulation occurs, resulting in deterioration of the battery cell. Moreover, overheating of the battery cell may be very serious from the viewpoint of safety. Therefore, a cooling system that achieves the optimum operating condition of the battery pack and improves the safety is indispensably required for the battery pack having a high output and a large capacity.

This cooling system mainly adopts a method of forcibly circulating the refrigerant to the inside of the battery pack to remove heat from the battery cell, that is, a contact type cooling method of the refrigerant on the surface of the battery cell or the unit module constituting the battery pack. As a refrigerant, a gas such as air is mainly used, and the whole is made of a contact-type air-cooling system.

In general, a unidirectional flap as shown in Fig. 1 is used in a contact type air-cooled type battery pack. Referring to FIG. 1, the conventional unidirectional flap 10 is a structure for preventing backflow of refrigerant by using a rubber material. When gas is discharged from a battery cell, Direction) is prevented.

However, in the conventional structure, when a short circuit occurs in the battery cell due to external environment or malfunction, the decomposition reaction of the electrolytic solution occurs at the positive electrode interface, thereby generating a large amount of gas. As a result, The case is ruptured and discharged to the outside of the battery cell. In general, such an internal gas contains poisonous components harmful to the human body such as carbon monoxide. When the gas discharged from the battery cell and the refrigerant flowing in the battery pack are mixed, the cooling efficiency deteriorates and a safety problem arises. For example, in the case of a vehicle, internal gas generated in the battery cell may flow into the passenger compartment during the circulation of the refrigerant, resulting in damage to the human body.

Accordingly, there is a high need for a battery pack that can prevent the gas generated from the unit cells from flowing into the passenger compartment in the circulation process of the refrigerant, or intermingling the refrigerant flowing along the refrigerant passage with the gas.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments. As described later, the module assembly cover is sealed in a unit of a battery module so as to isolate the battery modules from each other, A battery pack having a structure in which the gas is prevented from flowing back into the room such as a vehicle has been developed.

Accordingly, it is an object of the present invention to provide a battery pack having a structure in which a gas generated in a battery module is guided in a desired direction and vented so that gas can be prevented from flowing back into a room such as a vehicle will be.

It is still another object of the present invention to provide a middle- or large-sized battery pack having improved lifetime and safety by basically blocking the gas generated from the battery module and the coolant flowing along the coolant channel from being mixed with each other.

According to an aspect of the present invention, there is provided a battery pack comprising:

A module assembly in which a plurality of battery modules each having a structure in which a plurality of battery cells or unit modules are built as unit cells are arranged in close contact with each other;

A thermal pad mounted on an upper surface or a lower surface of the module assembly for heat dissipation of the module assembly by heat conduction; and a cooling plate closely attached to an outer surface of the heat dissipation pad;

A module assembly cover mounted on an outer circumferential surface of the cooling plate between the battery modules to prevent mixing of gas generated inside the module assembly and refrigerant present outside the module assembly;

A cover for covering the outer surface of the module assembly in a state that the cooling plate is exposed, and having a discharge port for discharging gas on one side thereof; And

A gas discharging member mounted on the module assembly for collecting gas discharged from the inside of the battery module and discharging the discharged gas to the discharging port;

As shown in FIG.

Accordingly, the middle- or large-sized battery pack according to the present invention can discharge the gas generated in the battery cells in a desired direction while being separated from the refrigerant flow path by mounting the gas discharging structure and the refrigerant flow path structure having a specific structure, It is possible to prevent the gas generated inside the battery cell from flowing back to the room such as the vehicle, thereby securing the safety of the driver.

The battery cell is not particularly limited as long as it is a rechargeable secondary battery. Preferably, the battery cell is a nickel-hydrogen secondary battery or a lithium secondary battery mediated by lithium ions. In one example, The battery cells may have a thin thickness and a relatively wide width and a length so as to minimize the total size of the battery cells when the battery cells are stacked.

The 'nickel-hydrogen secondary battery' is a secondary battery using nickel as a positive electrode, a hydrogen storage alloy as a negative electrode, and an aqueous alkali solution as an electrolyte. The nickel-hydrogen secondary battery has a higher energy density per unit volume than a nickel-cadmium battery, And can withstand overdischarge and overcharging. Since the capacity per unit volume is large, it may be preferable as an energy source of an electric vehicle or a hybrid electric vehicle.

In addition, the "lithium secondary battery" is, for example, as a cathode active material of a metal oxide and a negative electrode active material such as LiCoO _2, and using a carbon material or the like, placing a porous polymer separator between the anode and cathode, LiPF _6, etc. Aqueous electrolyte solution containing a lithium salt. During charging, the lithium ions of the positive electrode active material are released and inserted into the carbon layer of the negative electrode. In discharging, lithium ions in the carbon layer are released and inserted into the positive electrode active material. In the non-aqueous electrolyte, It can be a desirable energy source for various electronic products, electric vehicles or hybrid vehicles because it plays a role of moving medium, has high energy density and operating voltage, and has excellent preservation and lifetime characteristics.

In one specific example, the battery cell may have a structure in which an electrode assembly is embedded in a case of a laminate sheet including a metal layer and a resin layer, and then the outer circumferential surface is sealed by heat sealing. Specifically, the electrode assembly may be embedded in the pouch-shaped case of the aluminum laminate sheet. The battery cell having such a structure may also be referred to as a "pouch-shaped battery cell".

Such a battery cell can be constituted by a unit structure in which two or more units are surrounded by a high-strength cover member made of a synthetic resin or a metal material. The high-strength cover member protects a battery cell having low mechanical rigidity, It is possible to prevent the sealing portion of the battery cell from being separated by suppressing the repeated expansion and contraction of the battery. Accordingly, it becomes possible to manufacture a middle- or large-sized battery module with superior safety.

Therefore, the unit module includes two or more battery cells having electrode terminals connected in series and having a stacked structure, and a pair of battery cells, which are mutually coupled to surround the outer surfaces of the battery cells, And a high strength cell cover. A specific example of such a battery module is Korean Patent Application No. 2006-0045444 of the present applicant, which application is incorporated herein by reference.

In one specific example, the battery module may have a structure including a pair of upper and lower cases surrounding the outer surface in a state in which the upper surface or the lower surface where the heat radiation pad is exposed is exposed.

The configurations of the upper case and the lower case are not particularly limited, and may be configured in various shapes and sizes corresponding to the shape of the battery module and the size of the space mounted on the vehicle.

In this structure, the heat-radiating pad may preferably be formed in a number corresponding to the unit cells.

Therefore, the heat-radiating pad is directly in contact with the battery cell electrode terminal of the unit cell, so that the heat generated in the battery cell can be effectively transmitted.

Meanwhile, the cooling plate may be configured to be cooled by air, and preferably, the cooling plate may be formed of a plate-shaped metal plate.

In the case of a secondary battery, heat is generated in the charging / discharging process, and effectively discharging generated heat to the outside serves as an important factor for extending the life of the battery.

Therefore, the cooling plate may be made of a highly heat-conductive metal plate so that heat generated in the battery cells inside can be more easily discharged to the outside.

In one specific example, at least one of the opposite ends of the cooling plate may be a vertically curved structure, but is not limited to this structure, and preferably the cooling plate has at least one of the two sides of the battery module And the side end portion may extend vertically so as to surround one side surface.

And the first sealing member may be interposed at the interface between the cooling plate and the module assembly cover.

In this structure, it is preferable that the first sealing member is interposed in the unit of the battery module so as to isolate the battery modules, but it is not particularly limited as long as the structure can maintain the isolated state of the battery modules.

The second sealing member may include a supporting bar extending in a stacking direction of the module assembly, and a second sealing member extending from the first sealing member toward the second sealing member, And a sealing member sealed on the upper and lower surfaces of the supporting bar.

Therefore, the sealing member and the supporting bar secure the space for the refrigerant to flow, and the isolated state of the battery modules can be maintained.

In one specific example, the outlet of the pack cover may be additionally formed at one side of the lower surface.

On the other hand, a refrigerant inlet port and a refrigerant outlet port may be formed on the upper surface of the pack cover in opposite directions so that the refrigerant can flow from one side of the module assembly to the opposite side in a space between the pack cover and the cooling plate. The refrigerant inlet port and the refrigerant outlet port may protrude upward.

The refrigerant inlet and the refrigerant outlet may be formed in the pack cover so as to extend in a direction parallel to the unit cell stacking direction, but the present invention is not limited thereto.

The discharge member may be constructed, for example, of a hollow pipe structure.

The present invention also provides a battery pack in which at least two battery modules are mounted in a pack case, and a device using the battery module or the battery pack as a power source.

The battery pack or device according to the present invention can be manufactured by combining battery modules according to a desired output and capacity. Considering the mounting efficiency and structural stability as described above, the battery pack or device according to the present invention has a limited mounting space, A hybrid electric vehicle, or a plug-in hybrid electric vehicle or a power storage device, but the scope of application is not limited thereto.

The structure and manufacturing method of such a device are also well known in the art, so a detailed description thereof will be omitted herein.

As described above, the middle- or large-sized battery pack according to the present invention can prevent the gas from flowing back to the room such as a vehicle by constituting a structure in which gas generated in the battery module is guided in a desired direction and vented.

Further, it is possible to prevent the gas generated in the battery module and the refrigerant flowing along the refrigerant channel from being mixed with each other, thereby improving the life and safety of the battery pack.

Further, since cooling members such as a separate heat sink for improving the cooling efficiency of the battery module are not required, it is possible to reduce the cost as well as the volume of the battery pack.

1 is a perspective view of a conventional unidirectional flap;
2 is a perspective view of a pouch-shaped battery cell;
3 is a perspective view of a cell cover to which the battery cell of FIG. 2 is to be mounted for the construction of a unit module;
4 is an exploded perspective view of a battery module according to one embodiment of the present invention;
5 is a perspective view of a battery module according to the present invention;
6 is a vertical cross-sectional view taken along line AA 'of FIG. 3;
Figure 7 is a perspective view of a module assembly according to one embodiment of the present invention;
8 is a perspective view of the battery pack according to the present invention;
9 is a vertical sectional view of BB 'of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 2 is a perspective view of a pouch-type battery cell. FIG. 3 is a perspective view of a cell cover to which two battery cells of FIG. 2 are to be mounted for the configuration of a unit module.

Referring to these drawings, the pouch-shaped battery cell 50 has a structure in which two electrode leads 51 and 52 protrude from the upper end and the lower end of the battery main body 53, respectively. The outer case 54 is composed of two upper and lower units and has two side surfaces 55 and upper and lower ends 56, which are in mutual contact with each other, with an electrode assembly (not shown) mounted on a receiving portion formed on the inner surface thereof. And 57 are attached to the battery cell 50 to form the battery cell 50.

The exterior member 54 is made of a laminate structure of a resin layer / metal foil layer / resin layer so that heat and pressure are applied to both side surfaces 55 and upper and lower ends 56 and 57 which are in contact with each other, And may be adhered using an adhesive in some cases. Both side surfaces 55 are in direct contact with the same resin layer of the upper and lower sheathing members 54, so that they can be uniformly sealed by melting. On the other hand, since the electrode leads 51 and 52 protrude from the upper end portion 56 and the lower end portion 57, the sealing property is improved in consideration of the thickness of the electrode leads 51 and 52 and the heterogeneity with the material of the outer sheath member 54 The electrode leads 51 and 52 are thermally fused with a film sealing member 58 interposed therebetween.

The cell cover 100 has two built-in pouch-shaped battery cells (not shown) as shown in FIG. 2 and serves to complement the mechanical rigidity of the pouch-type battery cell 100 and facilitates the mounting to the module case do. The battery cells are mounted inside the cell cover 100 in a structure in which one side of the battery cells is bent in a state where they are connected in series and closely contacted with each other.

The cell cover 100 is composed of a pair of members 110 and 120 of a mutual coupling type, and is made of a high strength metal plate. A step 130 is formed on an outer surface adjacent to both ends of the cell cover 100 to facilitate fixing of the module and a step 140 is formed on the upper and lower ends. Further, the upper and lower ends of the cell cover 100 are formed with fixing portions 150 in the width direction, thereby facilitating mounting to the module case (not shown).

FIG. 4 is an exploded perspective view of a battery module according to an embodiment of the present invention, and FIG. 5 is a perspective view of a battery module according to an embodiment of the present invention.

1 to 3, the battery module 200 includes a module case composed of an upper case 240 and a lower case 250, a heat radiation pad 230 coupled to an upper surface of the module case, And a cooling plate (210).

The battery module 200 has a structure in which six unit modules 190 are mounted vertically and two battery cells 50 are built in each unit module so that a total of 12 battery cells 50 ). The electrode terminals are connected in series between the battery cells 50 and between the unit modules 190. The pair of battery cells 50 are bent in a ' ).

The battery module 200 is vertically mounted on a module case composed of an upper case 240 and a lower case 250. One side of the cell cover 100 of each of the unit modules 190 can be observed from the outside .

The upper surface of the unit modules 190 is closely adhered to the opened portions of the cell cover 100 in the longitudinal direction in units of the unit modules 190. The upper surfaces of the heat radiation pads 230 are bent The cooling plate 210 on which the extending portion 220 is formed is closely contacted.

The extended portion 220 of the cooling plate 210 is vertically bent in the downward direction and coupled to one side of the outermost unit module 190 (see FIG. 6) of the battery module 200, ) Is completed.

FIG. 6 is a schematic vertical cross-sectional view taken along line AA 'of FIG. 3, and FIG. 7 is a schematic perspective view of a module assembly according to an embodiment of the present invention. And FIG. 9 is a schematic vertical sectional view of BB 'of FIG. 6.

1 through 5, the battery pack includes a module assembly 500 in which a plurality of battery modules 200 are arranged in the longitudinal direction, a module assembly cover 500 mounted on the upper surface of the module assembly 500, 300 and a pack cover 510 surrounding the outer surface of the module assembly 500.

The pack cover 510 is formed with a discharge port 520 for discharging gas and a coolant inlet port 550 and a coolant outlet port 560 for flowing the coolant. The structure of the pack cover 510 will be described in detail later I will explain.

The module assembly cover 300 has a hollow frame shape and is formed to have a length corresponding to the module assembly 500. A first sealing member 310 is mounted on the lower surface of the module assembly cover 300, The upper surface of the module assembly 500 is isolated in units of the battery modules 200 since the module assembly covers 300 are sealed to each other.

A second sealing member 450 including a supporting bar 410 mounted in the longitudinal direction and a sealing member 420 sealed to the upper and lower surfaces of the supporting bar 410 is mounted on the module assembly cover 300.

The sealing member 420 sealed on the upper surface of the supporting bar 410 is closely attached to the lower surface of the pack cover 510 and the sealing member 420 sealed to the lower surface of the supporting bar 410. [ Is closely attached to the module assembly cover 300 so that heat generated in the battery module 200 is transferred to the battery pack 200 so that the battery module 200 can be discharged to the outside of the battery pack.

In the above structure, a gas exhaust member 400 in the form of a long pipe is mounted along the outer surface of the side surface of the module assembly 500 so as to easily discharge the gas generated from the battery module 200, A BMS 350 as a control means, and a PRI 360 are sequentially mounted.

On the other hand, the pack cover 500 has a structure in which the outer surface of the module assembly 500 is enclosed while one side of the cooling plate 210 is exposed. A discharge port 520 for guiding the gas to be collected and discharged to the outside is formed, and a discharge port 530 formed in a depressed shape is additionally formed on the lower center portion.

The coolant inlet port 550 and the coolant outlet port 560 are spatially separated from the discharge port 520 through which the gas is discharged so that the coolant is discharged from the module assembly 500 in a space between the pack cover 500 and the cooling plate 210, And protrude in opposite directions on the upper surface of the pack cover 500 so as to flow from one side of the pack cover 500 to the opposite side.

Accordingly, the heat generated in the battery module 200 is transferred to the flow space between the pack covers 510 through the cooling plate 210, and is easily discharged to the outside through the refrigerant outlet 560.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (20)

A module assembly in which a plurality of battery modules each having a structure in which a plurality of battery cells or unit modules are built as unit cells are arranged in close contact with each other;
A thermal pad mounted on an upper surface or a lower surface of the module assembly for heat dissipation of the module assembly by heat conduction; and a cooling plate closely attached to an outer surface of the heat dissipation pad;
A module assembly cover mounted on an outer circumferential surface of the cooling plate between the battery modules to prevent mixing of gas generated inside the module assembly and refrigerant present outside the module assembly;
A cover for covering the outer surface of the module assembly in a state that the cooling plate is exposed, and having a discharge port for discharging gas on one side thereof; And
A gas discharging member mounted on the module assembly for collecting gas discharged from the inside of the battery module and discharging the discharged gas to the discharging port;
The battery pack comprising: The middle- or large-sized battery pack according to claim 1, wherein the battery cell is a nickel-hydrogen secondary battery or a lithium secondary battery. The middle- or large-sized battery pack according to claim 1, wherein the battery cell is a pouch-shaped battery cell in which an electrode assembly is embedded in a battery case of a laminate sheet including a metal layer and a resin layer. The battery module according to claim 1, wherein the unit module comprises two or more battery cells having electrode terminals serially connected to each other and a connecting portion of the electrode terminals bent to form a laminated structure, And a pair of high-strength cell covers which are mutually coupled to surround the outer surfaces of the cells. The middle- or large-sized battery pack according to claim 1, wherein the battery module includes a pair of upper and lower cases surrounding an outer surface of the battery module in a state that an upper surface or a lower surface of the heat dissipation pad is exposed. The middle- or large-sized battery pack according to claim 1, wherein the heat radiating pads are formed in a number corresponding to the unit cells. The middle- or large-sized battery pack according to claim 1, wherein the cooling plate is cooled by air. The middle- or large-sized battery pack according to claim 1, wherein the cooling plate is formed of a plate-shaped metal plate. The middle- or large-sized battery pack according to claim 1, wherein the cooling plate has a side end extending vertically so as to cover at least one side of both sides of the battery module. The middle- or large-sized battery pack according to claim 1, wherein a first sealing member is interposed at an interface between the cooling plate and the module assembly cover. 11. The middle- or large-sized battery pack according to claim 10, wherein the first sealing member is interposed in a unit of a battery module so as to isolate the battery modules from each other. The middle- or large-sized battery pack according to claim 1, wherein a second sealing member is interposed at an interface between the module assembly cover and the pack cover. 13. The module of claim 12, wherein the second sealing member comprises: a supporting bar extending in the longitudinal direction of the module assembly; And
And a sealing member sealing the upper and lower surfaces of the supporting bar. The middle- or large-sized battery pack according to claim 1, wherein the discharge port of the pack cover is additionally formed at one side of the lower surface. The refrigerator according to claim 1, wherein a coolant inlet port and a coolant outlet port are formed on the upper surface of the pack cover in opposite directions so that the coolant can flow from one side of the module assembly to the opposite side in a space between the pack cover and the cooling plate Sized battery pack. The middle- or large-sized battery pack according to claim 15, wherein the coolant inlet port and the coolant outlet port protrude upward. The middle- or large-sized battery pack according to claim 1, wherein the coolant inlet port and the coolant outlet port extend in a direction parallel to the cell stacking direction and are formed in the pack cover. The battery pack according to claim 1, wherein the discharge member is a hollow pipe. A device according to any one of claims 1 to 18 used as a power source. 20. The device of claim 19, wherein the device is an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle or a power storage device.

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