KR101371396B1 - Unit Module of Novel Structure and Battery Module Comprising the Same - Google Patents

Abstract

According to the present invention, two or more plate-shaped battery cells are enclosed by an exterior member in an electrically connected state, and an interface member between the battery cells has a heating member that raises the temperature of the battery cell by heat generation upon application of current. It provides a unit module installed.

Description

Unit module of novel structure and battery module including same {Unit Module of Novel Structure and Battery Module Comprising the Same}

The present invention relates to a unit module of a novel structure, and more particularly, two or more plate-shaped battery cells are surrounded by an outer member in an electrically connected state, the application of current to the interface between the battery cells The present invention relates to a unit module having a structure in which a heat generating member for raising a temperature of a battery cell by heat generation is mounted.

Due to the development of technology and demand for mobile devices, the demand for secondary batteries is also rapidly increasing. Among them, lithium secondary batteries, which have high energy density, high operating voltage and excellent storage and life characteristics, It is widely used as an energy source.

The secondary battery is roughly classified into a cylindrical battery, a prismatic battery and a pouch-shaped battery according to the structural characteristics of the outside and the inside. Among them, the secondary battery can be stacked with a high degree of integration, and prismatic batteries and pouch- .

In addition, the secondary battery is attracting attention as an energy source for electric vehicles, hybrid electric vehicles, and the like, which is proposed as a solution for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels. Therefore, the type of applications using the secondary battery is very diversified due to the advantages of the secondary battery, and it is expected that the secondary battery will be applied to many fields and products from now on.

As the application fields and products of the secondary battery are diversified, the type of the battery is also diversified to provide an appropriate output and capacity. In addition, there is a strong demand for miniaturization and weight reduction of cells applied to the field and products.

For example, small mobile devices such as mobile phones, PDAs, digital cameras, notebook computers, and the like are used with one or two or four small light battery cells per device according to the miniaturization tendency of the products. On the other hand, medium and large devices such as electric vehicles and hybrid electric vehicles, due to the need for high output capacity, a battery module (or sometimes referred to as a "battery pack") electrically connecting a plurality of battery cells or unit modules is used. Since the size and weight of the battery module are directly related to the accommodation space and the output of the medium and large devices, manufacturers are trying to manufacture a battery module that is as small and lightweight as possible.

On the other hand, the battery module has a problem that does not fully exhibit the performance of the battery module due to the increase in the internal resistance of the battery cell at low temperatures, such as cold.

Specifically, in the case of an air-cooled battery module, a method of cooling the battery module by inhaling air in the vehicle is mainly used. When the outside temperature is low, the temperature inside the vehicle is also low. There is a limit to ascension.

Therefore, there is a high need for a technology that can fundamentally solve these problems.

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.

Specifically, an object of the present invention, when the heating element is mounted on the interface between the battery cells wrapped in the outer member, a unit that can produce a desired torque value in a short time the motor in a low temperature conditions such as cold To provide a module.

Still another object of the present invention is to provide an exterior member that can effectively increase the weight and size while effectively reinforcing the low mechanical rigidity of the battery cell and can be easily coupled without a separate fastening member.

Therefore, the unit module according to the present invention is surrounded by an outer member in a state in which two or more plate-shaped battery cells are electrically connected, and the interface between the battery cells, when the current is applied to heat the battery cells It is comprised by the structure with which the heat generating member which raises temperature is attached.

That is, the unit module of the present invention has a structure in which the heat generating member is mounted at the interface between the battery cells, and when the outside air is low temperature, the current is applied to the heat generating member to increase the temperature of the battery cell to improve the performance of the battery cell. You can restore normal operation in a short time.

In addition, the unit module of the structure can increase the temperature of the battery cell by the heat generating member itself without introducing air inside the vehicle to the battery cells through the air conditioner of the vehicle, thereby reducing the load applied to the vehicle by using the air conditioner. You can.

Further, by mounting the heat generating member between the battery cells it is possible to prevent the increase in the volume of the entire unit module to configure a unit module of a compact structure.

In the present invention, the plate-shaped battery cell is not particularly limited as long as it is a secondary battery capable of charging and discharging. For example, a lithium secondary battery, a nickel-hydrogen (Ni-MH) secondary battery, a nickel-cadmium (Ni-Cd) secondary battery And the like, and among these, a lithium secondary battery that provides a high output to weight may be preferably used.

The lithium secondary battery is classified into a cylindrical battery, a square battery, a pouch-type battery, and the like according to its shape. Among them, the battery cell of the present invention may be preferably applied to a plate-shaped battery cell in which a sealing portion formed by heat fusion is formed at an end portion of an outer circumferential surface thereof. have. In one preferred embodiment, the plate-shaped battery cell of the present invention may have a structure in which an electrode assembly having a positive electrode / separator / negative electrode structure is embedded in a battery case of a laminate sheet including a resin layer and a metal layer, A light weight pouch-type battery in which an electrode assembly is embedded in a battery case of a laminate sheet including an inner resin layer for a battery, a barrier metal layer, and an outer resin layer having excellent durability.

In the pouch-type battery, the battery case may be formed in various structures. For example, the battery case may be formed as a member of two units to seal the upper and lower contact portions after storing the electrode assembly in the upper and / or lower inner surfaces. It may be a structure. A pouch-type battery having such a structure is disclosed in PCT International Application No. PCT / KR2004 / 003312 to the applicant, which is incorporated by reference in the context of the present invention.

The electrode assembly is composed of an anode and a cathode so as to be capable of charging and discharging. For example, a structure in which an anode and a cathode are stacked with a separator interposed therebetween may be a jelly-roll type, a stack type, or a stack- Lt; / RTI > The positive electrode and the negative electrode of the electrode assembly may have a form in which electrode tabs thereof protrude directly to the outside of the battery, or the electrode tabs may be connected to separate leads and protrude out of the battery.

In one preferred example, the heat generating member may be partially or entirely interposed between the battery cells. That is, part or all of the heat generating member is interposed in close contact with the battery cells, thereby directly transferring heat generated from the heat generating member to the battery cells.

If the size of the heat generating member is too large, the weight or volume of the unit module increases, and if it is too small, the heat generating effect is relatively reduced, which is not preferable. Therefore, the size of the heat generating member is preferably made of an appropriate size that can effectively absorb and discharge the heat of the battery cells. For example, in a structure in which at least a portion of the heat generating member is interposed between the stacked battery cells, the width of the heat generating member is 50 to 100% based on the width of the battery cell, thereby increasing the size of the unit module. It is possible to carry out the desired fever without causing it.

In another preferred embodiment, the heat generating member is made of a PTC (Positive Temperature Coefficient) heater (heater), to stop the heat generated when the temperature of the heat generating member exceeds a predetermined value to prevent the battery cell ignition or explosion in advance can do.

In another preferred embodiment, the heat generating member has a structure comprising a heat generating plate of PTC material and a power terminal formed at one end of the heat generating plate for applying electricity to the heat generating plate, it is drawn through the power terminal Electrical energy is converted into thermal energy by the heating plate.

In one specific example, the power supply terminal may have a structure in which one end is connected to the heating plate and the other end is connected to an external power source, and is mounted in the electrically insulating terminal housing.

The heat generating plate is not particularly limited as long as the heat generating shape is easy, but for example, the heat generating plate has a structure in which the power terminal protrudes from one edge of the rectangular plate, so as not to increase the volume of the entire unit module.

The power terminal is not particularly limited as long as it is a structure capable of supplying electricity to the heating plate, but may be formed, for example, of a plug type.

The heat generating member may have a structure in which electricity is supplied from the electric power supply for the vehicle to increase the temperature of the battery cell. For example, the electric power supply for the vehicle may be a lead acid battery. In some cases, some or all of the electricity supplied from the battery cell may be configured to be applied to the heat generating member, and the supply from the battery cell may be configured to apply the electricity supplied from the electric power source for the electric field to the heat generating member together. have.

Meanwhile, the battery cells may have a structure in which electrode terminals are formed at upper and lower ends, and electrode terminals are interconnected in series.

In the above structure, the connection parts of the electrode terminals are bent to form a battery cell in a stacked structure, and the entire outer surface of the battery cell stack except for the electrode terminal part is surrounded by a pair of exterior members which are mutually coupled to each other, thereby The member prevents the sealing part of the battery cell from being separated by suppressing repeated expansion and contraction during charging and discharging while protecting the battery cell having low mechanical rigidity.

The battery cells or the respective unit modules in the unit module are connected in series and / or parallel manner, and in one preferred embodiment, the battery cells are arranged in series in the longitudinal direction such that their electrode terminals are continuously adjacent to each other. After combining the electrode terminals in, it is possible to manufacture a plurality of unit modules by folding the battery cells in two or more units so as to overlap and wrapped by the exterior member in a predetermined unit.

In the above structure, the outer member has an inner surface structure corresponding to the outer surface shape of the battery cell stack, and in particular, it consists of a structure that is coupled in an assembly fastening method that does not require a separate fastening member.

In one preferred embodiment, one side lower end of the exterior member is formed with a slot corresponding to the terminal housing so that the terminal housing can be inserted in order to fix the position of the heating member, the heating member is in the correct position by the external force It is possible to prevent the departure.

The coupling of the electrode terminals can be realized in various ways such as welding, soldering, mechanical fastening, etc., and can be achieved preferably by welding.

On the other hand, in the secondary battery, if excessive heat is generated during charging and discharging and the heat generated in this way is not effectively discharged to the outside, serious problems may occur in terms of battery life and safety. Of course, in such a high heat generating state, no electricity should be applied to the heat generating member.

Considering this point as a whole, it is preferable that the exterior member is made of a high thermal conductive metal plate so that heat generated from the unit cell therein can be more easily discharged to the outside.

In one preferred embodiment, the exterior member of the present invention has a structure in which a plurality of linear protrusions spaced apart from each other in the width direction (lateral direction) are formed on its outer surface, so that the unit member is stacked Refrigerant (for example, air) can flow in the width direction, so that the cooling efficiency can be further improved.

In addition, the upper protrusion and the lower protrusion of the linear protrusions are preferably formed with mutually opposite shapes, respectively, and the shape of the protrusions has a shape corresponding to each other and adjacent unit modules when stacked between the module modules There is an effect of preventing the stacking position from being reversed or shifted.

In some cases, the plurality of protrusions of the protrusions may be configured such that both ends thereof are smaller than the width of the cell cover, such that the refrigerant flows in the longitudinal direction of the exterior member.

In another preferred embodiment, a step size of a predetermined size may be formed at the side edge of the exterior member to facilitate fixing of the module when the frame member is coupled with the frame member. Preferably, a step of a predetermined size may be formed on side surfaces adjacent to the top and bottom to facilitate fixing of the module, and in some cases, the step may be formed on sides of the left and right ends of the exterior member. More preferably, a step is formed in both the upper and lower ends and the left and right ends of the exterior member, thereby making it possible to more securely fix the module.

The present invention also provides a battery module manufactured by combining the unit module according to a desired output and capacity.

The present invention also provides a vehicle including the battery module and having a limited mounting space and exposed to frequent vibration and strong impact.

In this case, the vehicle may be an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

Electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles using the battery module as a power source is known in the art, so a detailed description thereof will be omitted.

As described above, the unit module according to the present invention is a heating member for promoting the heat generation of the battery is mounted at the interface between the battery cells, so that the motor to give a desired torque value in a short time under extreme temperature conditions Can be.

In addition, the unit module according to the present invention can minimize the increase in weight and size while complementing the low rigidity of the battery cell by the outer member, and in a simple assembly method without using a plurality of members for mechanical fastening and electrical connection By lowering the overall manufacturing cost and reducing the risk of short-circuit or breakage during operation or operation, it is possible to easily manufacture a battery module having a desired output and capacity by using the unit module as a unit.

1 is an exploded view of a unit module according to one embodiment of the present invention;
2 is a perspective view of the heat generating member of FIG. 1;
3 is an enlarged schematic view of a portion where the heat generating member of FIG. 1 is coupled to a battery cell and an exterior member;
4 is a perspective view of a unit module stack according to another embodiment of the present invention;
5 is a partially enlarged view showing a coupling structure of the exterior member;
6 is a perspective view of a battery module according to another embodiment of the present invention;
7 is a graph illustrating a change in temperature of a unit module without a heating member;
8 is a graph illustrating a temperature change of a unit module equipped with a heating member.

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.

1 is an exploded view schematically showing a unit module according to an embodiment of the present invention, and FIG. 2 is a perspective view of the heat generating member of FIG. 1.

Referring to these drawings, the unit module 201 is surrounded by a pair of exterior members 210 and 220 in a state in which two plate-shaped battery cells 230 and 240 are electrically connected, and the heat generating member 250. Is mounted at an interface between the battery cells 230 and 240, thereby raising the temperature of the battery cells 230 and 240 by heat generation when an electric current is applied. That is, the heating member 250 receives electricity from a lead-acid battery (not shown), which is a power source for a vehicle, and converts it into thermal energy, thereby forming battery cells 230 and 240 positioned on the upper and lower surfaces of the heating member 250. Raise the temperature.

The plate-shaped battery cells 230 and 240 have an electrode assembly having a positive electrode / separation membrane / cathode structure built into a battery case of a laminate sheet including a resin layer and a metal layer, and the width w of the heat generating member 250 is a battery cell ( It is about 95% of the width (W) of the 230).

The heating member 250, which is a PTC heater, is composed of a heating plate 252 and a power supply terminal 254 made of PTC material, and the power supply terminal 254 is a heating plate 252 for applying electricity to the heating plate 252. It is formed at one end of the side.

The power supply terminal 254 is mounted in the electrically insulating terminal housing 256 in a structure in which one end thereof is connected to the heat generating plate 252 and the other end thereof is connected to an external power source (not shown).

The heat generating plate 252 is a rectangular plate, and the power terminal 254 formed of a plug type is configured to protrude from one edge of the rectangular plate.

The battery cells 230 and 240 have electrode terminals 232 and 234 formed at the top and bottom thereof, respectively, and the electrode terminals 232 and 234 are interconnected in series by welding.

In addition, the unit module 201 is bent the connecting portion of the electrode terminals 232, 234 battery cells 230, 240 is a laminated structure, except for the electrode terminal portion of the battery cells 230, 240 The entire outer surface of the stacked battery cell stack is surrounded by a pair of exterior members 210 and 220 coupled to each other.

The exterior members 210 and 220, which are metal plates, have an inner surface structure corresponding to the outer surface shape of the battery cell stack, and are coupled to each other in an assembled fastening manner.

In addition, five linear protrusions 211a, 211b, 211c, 211d, and 211e spaced apart from each other in the width direction are formed on the outer surface of the exterior member 210.

3 is a schematic diagram showing an enlarged portion of the heat generating member of FIG. 1 coupled to the battery cell and the exterior member.

Referring to FIG. 3 together with FIG. 1, the lower side of one side of the exterior member 210 has a size corresponding to the terminal housing 256 so that the terminal housing 256 can be inserted to fix the position of the heating member 250. Slot 216 is formed.

In addition, the stepped portions 217 and 218 of a predetermined size are formed on the side surfaces adjacent to the top and bottom of the exterior member and the side surfaces adjacent to the left and right ends of the exterior member, so that the frame member (not shown) and the unit module 201 are formed. To facilitate fastening.

4 is a perspective view schematically showing a unit module stack according to another embodiment of the present invention, FIG. 5 is a partially enlarged view schematically showing a coupling structure of an exterior member, and FIG. A perspective view of a battery module according to another embodiment of the present invention is schematically shown.

Referring to these drawings, the unit module stack 200 is zigzag after connecting the four unit modules (201, 202, 203, 204) made in a structure that wraps the battery cells in the outer member 210 in series It consists of a laminated structure.

The exterior member 210 includes a pair of covers 211 and 212, and coupling portions 230 are formed at both ends thereof.

The engaging portion 230 may include fastening protrusions 222a formed at both ends of the cover 212 so as to be engaged by an elastic coupling when the covers 211 and 212 are pressed to face each other. 222b and fastening units that are combinations of fastening grooves 221a and 221b formed in the cover 211 in a shape corresponding to the fastening protrusions 222a and 222b. Six fastening units are formed at equal intervals in the longitudinal direction at both ends of the exterior member 210, and may be a quadrangular A or a circular B in plan view. Therefore, a strong mechanical coupling is possible without having to go through a separate coupling member or processing process for assembling the exterior member 210, and such a simple coupling method is particularly preferable for application to a mass production process.

The battery module 300 has a structure in which the unit module stack 200 is mounted on the upper and lower assembled cases 311 and 312 in an upright position to the side, and an input / output terminal 320 is disposed on the front surface of the upper case 311. ) Is formed. A protective member 330 is formed on the front surface of the lower case 312, and a bus bar (not shown) for electrical connection with the input / output terminal 320 is formed therein.

Meanwhile, linear protrusions 211a, 211b, 211c, 211d, and 211e are spaced apart from each other in the width direction on the outer surface of the exterior member 210, and both ends of the cover 211 have a length in the width direction. Linear protrusions 211a and 211e shorter than 211 are formed at diagonal positions with each other.

FIG. 7 is a graph showing a temperature change of a unit module without a heating member in the structure of FIG. 1, and FIG. 8 is a graph showing a temperature change of a unit module with a heating member.

Specifically, the graph of Figure 7 shows the temperature change of the surface of the battery cell through the self-discharge of the battery cells and the graph of Figure 8 shows the temperature change of the surface of the battery cells using the temperature rise of the heating member with the self-discharge of the battery cells have.

Referring to these drawings, it can be seen that the temperature increase effect of the unit module (FIG. 8) equipped with the heating member at the same time is about 25% better than the unit module (FIG. 7) without the heating member mounted.

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 (21)

Two or more plate-shaped battery cells are wrapped by an exterior member in an electrically connected state, and an interface member between the battery cells is provided with a heating member for raising the temperature of the battery cell by heat generation upon application of current. ;
The heat generating member includes a heat generating plate of PTC material and a power terminal formed at one end of the heat generating plate to apply electricity to the heat generating plate;
The power supply terminal is mounted in an electrically insulating terminal housing in a structure in which one end is connected to the heat generating plate and the other end is connected to an external power source;
A lower end of one side of the exterior member is formed with a slot corresponding to the terminal housing so that the terminal housing can be inserted to fix the position of the heating member;
Engaging portions are formed at both ends of the exterior member, and when the exterior members are pressed in contact with each other to face each other, the engaging protrusions having a circular or polygonal shape are formed so as to be engaged by elastic coupling. Unit module, characterized in that the fastening groove of the shape corresponding to the fastening projection is formed. The unit module according to claim 1, wherein the plate-shaped battery cell has a structure in which an electrode assembly having a cathode / separator / cathode structure is built in a battery case of a laminate sheet including a resin layer and a metal layer. The unit module of claim 1, wherein the width of the heat generating member is 50 to 100% based on the width of the battery cell. The unit module of claim 1, wherein the heat generating member is a PTC (Positive Temperature Coefficient) heater. delete delete The unit module of claim 1, wherein the heat generating plate is a rectangular plate, and a power terminal protrudes from one edge of the rectangular plate. The unit module of claim 1, wherein the power supply terminal is formed in a plug type. The unit module of claim 1, wherein the heat generating member is supplied with electricity from an electric power source for a vehicle. The unit module of claim 1, wherein each of the battery cells has electrode terminals formed at an upper end and a lower end thereof, and electrode terminals are connected to each other in series. The method of claim 10, wherein the connecting portion of the electrode terminal is bent to form a laminated structure, the entire surface of the battery cell laminate except for the electrode terminal portion is surrounded by a pair of outer member which is mutually coupled to each other. Unit module. The unit module of claim 11, wherein the exterior member has an inner surface structure corresponding to the outer surface shape of the battery cell stack and is coupled in an assembly fastening manner. delete The unit module of claim 10, wherein the electrode terminals are coupled by welding. The unit module of claim 11, wherein the exterior member is made of a metal plate. The unit module of claim 11, wherein a plurality of linear protrusions are formed on an outer surface of the exterior member and spaced apart from each other in a width direction (lateral direction). 12. The unit module according to claim 11, wherein a step of a predetermined size is formed on side surfaces adjacent to the top and bottom of the exterior member to facilitate fixing of the module. 12. The unit module according to claim 11, wherein a step of a predetermined size is formed on side surfaces adjacent to left and right ends of the exterior member to facilitate fixing of the module. A battery module, characterized in that the unit module is manufactured by combining according to the required output and capacity according to claim 1. A vehicle comprising the battery module according to claim 19 as a power source. 21. The vehicle of claim 20, wherein the vehicle is an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

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