Title of the invention: Battery module with improved cooling efficiency and battery pack including the same
Technical field
[One]
The present invention relates to a battery module with improved cooling efficiency and a battery pack including the same, and more specifically, a battery module having a simplified manufacturing process while showing improved cooling efficiency using a cooling fin and a thermally conductive resin layer, and including the same It relates to a battery pack.
[2]
This application is an application for claiming priority for Korean Patent Application No. 10-2018-0087424 filed on July 26, 2018, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
Background
[3]
Currently commercialized secondary batteries include nickel cadmium batteries, nickel hydride batteries, nickel zinc batteries, and lithium secondary batteries, among which lithium secondary batteries have little memory effect compared to nickel-based secondary batteries, so charging and discharging are free. The self-discharge rate is very low and the energy density is high.
[4]
These lithium secondary batteries mainly use lithium-based oxides and carbon materials as a positive electrode active material and a negative electrode active material, respectively. A lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate to which the positive electrode active material and the negative electrode active material are applied, respectively, are disposed with a separator therebetween, and a case for sealing the electrode assembly together with an electrolyte solution, that is, a battery case.
[5]
In general, lithium secondary batteries may be classified into can-type secondary batteries in which an electrode assembly is embedded in a metal can, and pouch-type secondary batteries in which an electrode assembly is embedded in a pouch of an aluminum laminate sheet, depending on the shape of the exterior material.
[6]
In recent years, secondary batteries are widely used not only in small devices such as portable electronic devices, but also in mid- to large-sized devices such as automobiles and power storage devices. When used in such a medium-sized device, a large number of secondary batteries are electrically connected to increase capacity and output. In particular, pouch-type cells are widely used in such medium-sized devices due to the advantage of easy stacking.
[7]
However, the pouch-type cell is generally packaged with a battery case made of a laminate sheet of aluminum and polymer resin, so that mechanical rigidity is not large. Therefore, when configuring a battery module including a plurality of pouch-type cells, a frame is often used to protect the secondary battery from external impacts, prevent its flow, and facilitate stacking.
[8]
The frame may be replaced with various other terms such as a cartridge, and it is usually configured in the form of a square plate with an empty central portion, and at this time, the four side portions are configured to surround the outer periphery of the pouch-type cell. In addition, such a frame is used in a form in which a plurality of the battery modules are stacked, and the pouch-type cell may be located in an internal empty space generated when the frame is stacked.
[9]
Meanwhile, referring to FIG. 1, a conventional battery module structure is shown. In such a conventional battery module structure, when a plurality of pouch-type cells 1 are stacked using a plurality of frames 2, a plate-shaped Cooling efficiency is improved by applying the cooling fins (3).
[10]
The secondary battery may be used in a high temperature environment such as summer, and heat may also be generated by the secondary battery itself. In this case, when a plurality of secondary batteries are stacked on top of each other, the temperature of the secondary battery may be further increased. If the temperature is higher than an appropriate temperature, the performance of the secondary battery may deteriorate, and in severe cases, there is a risk of explosion or ignition. Therefore, when configuring the battery module, the cooling fin 3 is applied to contact the surface of the pouch-type cell 1, and the cooling fin 3 is brought into contact with the cooling plate 4 located under the battery module. A configuration that prevents an overall temperature rise is widely used.
[11]
However, in the case of configuring a battery module by interposing each of the pouch-type cells 1 facing the cooling fins 3, which are typically made of a metal material, the pouch-type cells 1 and the cooling fins 3 are stacked. / There is a problem in that the process of fixing takes a lot of time and thus productivity is lowered, and it is difficult to obtain a sufficient cooling effect with only the cooling fins 3.
[12]
Accordingly, there is an urgent need to develop a battery module structure that solves the problem of fairness and has an additional cooling path in addition to a cooling path composed of a pouch-type cell-cooling fin.
Detailed description of the invention
Technical challenge
[13]
The present invention, as invented in consideration of the above-described problems, simplifies the process of combining cooling fins and pouch-type cells and combining pouch-type cells in a module case, and also, cooling efficiency by varying the cooling path of the battery module. Its purpose is to improve.
[14]
However, the technical problem to be solved by the present invention is not limited to the above-described problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.
Means of solving the task
[15]
A battery module according to an embodiment of the present invention for solving the above-described problems includes: a module body including a cell assembly stack formed by stacking a plurality of cell assemblies and a module case accommodating the cell assembly stack; And a pair of heat sinks disposed above and below the module body to dissipate heat transferred from the module case, wherein the cell assembly includes: at least one battery cell; A cartridge accommodating the battery cell; And a pair of thermally conductive resin layers filling an empty space formed between the upper end of the battery cell and the cartridge and between the lower end of the battery cell and the cartridge.
[16]
The cartridge has a rectangular parallelepiped shape with both sides open, and the battery cell may contact the inner side of the cartridge.
[17]
The cartridge has a rectangular parallelepiped shape with both sides open, and an insulating sheet may be interposed between the battery cell and the inner surface of the cartridge.
[18]
The top and bottom of the battery cell may contact the thermally conductive resin layer.
[19]
The cartridge may include an injection port for injecting a resin for forming the thermally conductive resin layer and a discharge port for discharging the injected resin on the upper and lower surfaces thereof.
[20]
The injection port may be formed at a central portion of the lower surface of the cartridge, and the discharge port may be formed at both ends of the lower surface of the cartridge in the longitudinal direction.
[21]
The injection port may be formed at a center portion of the upper surface of the cartridge, and the discharge port may be formed at both ends of the upper surface of the cartridge in the longitudinal direction.
[22]
The battery module may further include a pair of thermal interface material layers (TIM) interposed between the module body and the heat sink.
[23]
Meanwhile, a battery pack according to an embodiment of the present invention includes at least one battery module according to an embodiment of the present invention.
Effects of the Invention
[24]
According to an aspect of the present invention, a process of combining the cooling fin and the battery module is simplified, so that productivity may be improved.
[25]
According to another aspect of the present invention, in addition to the heat dissipation path using the cooling fins, cooling efficiency may be improved by securing an additional cooling path capable of discharging heat simply and efficiently.
Brief description of the drawing
[26]
The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of ​​the present invention together with the detailed description of the present invention to be described later. It is limited only to and should not be interpreted.
[27]
1 is a view showing a structure of a conventional battery module to which a cooling fin is applied.
[28]
2 is a perspective view showing a battery module according to an embodiment of the present invention.
[29]
3 is a perspective view illustrating a cell assembly stack applied to a battery module according to an embodiment of the present invention.
[30]
4 is a perspective view illustrating a cell assembly applied to a battery module according to an embodiment of the present invention.
[31]
5 is a perspective view showing a battery cell constituting the cell assembly shown in FIG. 4.
[32]
6 is a perspective view showing a cartridge constituting the cell assembly shown in FIG. 4.
[33]
7 is a view showing the lower surface of the cartridge shown in FIG.
[34]
8 is a view showing a form in which the battery cell and the cartridge shown in FIGS. 5 and 6 are combined.
[35]
9 is a view showing a process of completing a cell assembly by injecting a thermally conductive resin into the assembly of the battery cell and the cartridge shown in FIG. 8.
[36]
10 is a schematic diagram showing a path in which cooling is performed in a battery module according to an embodiment of the present invention.
Mode for carrying out the invention
[37]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of ​​the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention, and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations.
[38]
[39]
First, an overall structure of a battery module according to an embodiment of the present invention will be schematically described with reference to FIGS. 2 and 3.
[40]
2 is a perspective view showing a battery module according to an embodiment of the present invention, and FIG. 3 is a perspective view showing a cell assembly stack applied to the battery module according to an embodiment of the present invention.
[41]
Referring to FIG. 2, a battery module according to an embodiment of the present invention may include a module body 100 and a heat sink 200 disposed above and below the module body 100, and the module body ( A thermal interface material layer (TIM) 300 disposed between the 100 and the heat sink 200 may be further included.
[42]
The module main body 100 is obtained by accommodating a cell assembly stack 120 having a form in which a plurality of cell assemblies 121 are stacked in a module case 110 (see FIG. 10 ). The plurality of cell assemblies 121 are stacked so that the widest surfaces of the cell assembly 121 face each other and contact each other.
[43]
The heat sink 200 is disposed above and below the module body 100 to directly/indirectly contact the upper and lower surfaces of the module case 110 to discharge heat to the outside. That is, heat generated from the module body 100, more specifically, heat generated from the battery cell 10 to be described later, and conducted to the module case 110, is discharged to the outside.
[44]
The heat sink 200 may have a space capable of accommodating a liquid cooling fluid (eg, water) therein to improve the efficiency of such heat dissipation, and in this case, the cooling fluid flows into the internal space. In addition, a pipe 210 capable of flowing the introduced cooling fluid to the outside may be provided.
[45]
The heat sink 200 may be made of a metal material having excellent thermal conductivity, such as copper or a copper alloy.
[46]
Meanwhile, as described above, the battery module according to an embodiment of the present invention may further include a TIM layer 300 interposed between the module body 100 and the heat sink 200. The TIM layer 300 transfers heat from the module body 100 to the heat sink 200 by preventing an empty space in which no contact is made between the upper and lower surfaces of the module body 100 and the heat sink 200. This can be done more efficiently.
[47]
The TIM layer 300 is made of a thermal interface material (TIM), and such a TIM includes, for example, aluminum oxide (Al 2 O 3 ), boron nitride (BN), zinc oxide (ZnO), etc. Thermal greese comprising material(s) having thermal conductivity and low electrical conductivity may be used.
[48]
When the module body 100 and the heat sink 200 directly contact each other without the TIM layer 300 interposed, the heat transfer path may be shorter compared to the case where the TIM layer 300 is interposed. . However, due to empty spaces that may occur at the bonding interface between the surface of the module case 110 made of a metal material or a plastic material and the surface of the heat sink 200 made of a metal material, there is a problem that the practical thermal conductivity is further reduced. Can occur.
[49]
Accordingly, the TIM layer 300 may be interposed between the module body 100 and the heat sink 200 in order to completely fill the empty space with the TIM to improve substantial thermal conductivity.
[50]
[51]
Next, a specific structure of the cell assembly 121 constituting the battery module according to an embodiment of the present invention will be described with reference to FIGS. 4 to 8.
[52]
FIG. 4 is a perspective view illustrating a cell assembly applied to a battery module according to an exemplary embodiment of the present invention, and FIG. 5 is a perspective view illustrating a battery cell constituting the cell assembly illustrated in FIG. 4. 6 is a perspective view showing a cartridge constituting the cell assembly shown in FIG. 4. In addition, FIG. 7 is a view showing the lower surface of the cartridge shown in FIG. 6, and FIG. 8 is a view showing a form in which the battery cell and the cartridge shown in FIGS. 5 and 6 are combined. In addition, FIG. 9 is a view showing a process of completing a cell assembly by injecting a thermally conductive resin into the assembly of the battery cell and the cartridge shown in FIG. 8.
[53]
First, referring to FIG. 4, each of a plurality of cell assemblies 121 constituting a battery module according to an embodiment of the present invention includes at least one battery cell 10 and a cartridge accommodating the battery cell 10 ( 20) and a thermally conductive resin layer 30 filling the empty space between the battery cell 10 and the cartridge 20.
[54]
Referring to FIG. 5, the battery cell 10 is a pouch-type battery cell, an electrode assembly (not shown), a pouch case 11, a pair of electrode leads 14, and an inner surface of the pouch case 11 And a pair of sealant 15 interposed between the electrode lead 14 and the electrode lead 14.
[55]
Although not shown in the drawings, the electrode assembly has a form in which a separator is interposed between a positive electrode plate and a negative electrode plate that are alternately repeatedly stacked, and it is preferable that separators are respectively positioned for insulation at the outermost sides of both sides.
[56]
The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer coated on at least one surface thereof, and is formed to protrude a positive electrode uncoated region region, which is not coated with a positive electrode active material, at one end of the positive electrode uncoated region region. It functions as a positive electrode tab connected to (14).
[57]
Similarly, the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer coated on at least one surface thereof, and is formed to protrude an uncoated region on which the negative active material layer is not coated at one end, and the uncoated region is an electrode lead. It functions as a negative electrode tab connected to (14).
[58]
In addition, the separator is interposed between the positive electrode plate and the negative electrode plate to prevent direct contact between electrode plates having different polarities, but may be made of a porous material in order to allow the movement of ions by using an electrolyte as a medium between the positive plate and the negative plate. have.
[59]
The pouch case 11 may be formed of an upper case covering an upper portion of the electrode assembly and a lower case covering the lower portion, and each of the upper case and the lower case corresponds to a first resin layer/intermediate layer corresponding to the innermost layer. It may be made of a multilayer pouch film composed of a metal layer/a second resin layer corresponding to the outermost layer.
[60]
The first resin layer forming the innermost surface of the pouch film may be made of a resin having heat-sealing properties so that when heat is applied while the upper and lower cases are in contact with each other. As such a first resin layer, non-stretched polypropylene, polypropylene, or a mixture thereof may be used. As the metal layer, a metal having excellent thermal conductivity, such as aluminum (Al), may be used. In addition, as the second resin layer constituting the outermost layer, polyethylene terephthalate, nylon, or a mixture thereof may be used.
[61]
The pouch case 11 extends in the circumferential direction of the accommodating portion 12 and the accommodating portion 12 accommodating an electrode assembly (not shown), and is thermally fused with the electrode lead 14 drawn out to the pouch case. It includes a sealing portion 13 for sealing (12).
[62]
The electrode lead 14 is divided into a positive electrode lead connected to the positive electrode tab and a negative electrode lead connected to the negative electrode tab, and each of the positive electrode lead and the negative electrode lead is drawn out of the pouch case 11. In the drawings of the present invention, only a case in which the pair of electrode leads 14 are drawn out in different directions is illustrated, but this is exemplary, and the pair of electrode leads 14 may be drawn out in the same direction.
[63]
Meanwhile, the electrode lead 14 of the battery cell 10 is not shown in the drawings other than FIG. 5, which is for convenience of drawing, and as described above, the battery cell 10 applied to the present invention. In ), the pair of electrode leads 14 may have a shape drawn out to one or both sides of the battery cell 10.
[64]
[65]
Next, referring to FIGS. 6 to 9, the cartridge 20 applied to the present invention has a rectangular frame shape with both sides open and hollow so as to accommodate the battery cell 10, and at least one When the battery cell 10 is accommodated, the outer surface of the battery cell 10 or the cell stack formed by stacking the battery cells 10 may contact the inner surface of the cartridge 20. In addition, the cartridge 20 is preferably made of a metal material such as aluminum having excellent thermal conductivity in order to function as a cooling fin for dissipating heat generated from the battery cell 10, and such a metal material cartridge 20 An insulating sheet may be interposed between the outer surface of the cell stack and the inner surface of the cartridge 20 in order to reinforce insulation between the battery cell 10 and the battery cell 10.
[66]
In order to allow the cell stack to be inserted into the accommodation space inside the cartridge 20, the accommodation space inside the cartridge 20 has a shape and size corresponding to the battery cell 10 or the cell stack.
[67]
However, as shown in FIG. 9, since the thermally conductive resin layer 30 must be formed inside the cartridge 20, the upper and lower ends of the battery cell 10 It means) and a certain space (S) is formed between the inner surface of the cartridge (20).
[68]
Referring to FIG. 7, the cartridge 20 includes an injection port 20a and a discharge port 20b formed on upper and lower surfaces. The injection hole 20a is formed through the center of the upper and lower surfaces of the cartridge 20 in the longitudinal direction and functions as an injection passage for the resin paste for forming the thermally conductive resin layer 30.
[69]
In addition, in the discharge port 20b, the upper and lower surfaces of the cartridge 20 are formed through both ends in the longitudinal direction so that the thermally conductive resin paste injected through the injection port 20a is applied to the battery cell 10 or the cell stack and the cartridge ( 20) It is possible to know whether all of the empty spaces S formed between are filled. That is, when the injection of the thermally conductive resin paste is started through the injection hole 20a located at the center of the lower surface of the cartridge 20, the thermally conductive resin paste is filled in a direction from the longitudinal center of the cartridge 20 toward both ends. And, when the thermally conductive resin paste is discharged to the outside through the discharge ports 20b located at both ends of the cartridge 20 in the longitudinal direction, the operator can see that the empty space S is all filled with the thermally conductive resin paste. So that the filling operation can be stopped.
[70]
The thermally conductive resin layer 30 is a layer made of a material (eg, graphite) in which an additive that imparts thermal conductivity to a resin such as epoxy is added, and a thermally conductive paste is applied between the battery cell 10 and the cartridge 20. It is obtained by filling the empty space (S).
[71]
The thermally conductive resin layer 30 fills the empty space S in the cartridge 20 to fix the battery cell 10 in the cartridge 20, and the lower portion of the battery cell 10 and the cartridge 20 An empty space is not generated between the inner surfaces so that heat can be well transferred from the battery cell 10 to the cartridge 20. As such, the thermally conductive resin layer 30 may add a polymeric binder component in the process of manufacturing the thermally conductive resin paste in consideration of the purpose of fixing.
[72]
On the other hand, in the battery module according to the present invention, a plurality of cell assemblies 121 are stacked, so that coupling between the battery cells 10 and the cartridge 20 is made through the filling of resin for each cell assembly 121. By doing so, the density distribution of the resin constituting the thermally conductive resin layer 30 can be uniformly formed as a whole.
[73]
A battery in a manner in which the space formed between the battery cell 10 and the module case 110 is filled with resin after the plurality of battery cells 10 are directly accommodated in the module case 110 without being accommodated in the cartridge 20. In the case of manufacturing a module, the density of the resin constituting the thermally conductive resin layer 30 may be formed very unevenly for each location.
[74]
That is, when the number of battery cells 10 accommodated in the module case 110 increases, the thickness of the cell stack formed by collecting the battery cells 10 becomes very thick. In this case, when a resin is injected by forming an injection hole on the upper and/or lower surface of the module case 110, the density of the resin at a position near and far from the injection hole may show a very large difference. This may lead to an uneven product quality. In the case of the battery module according to the present invention, since the resin filling operation is performed within a minimized space, this problem can be solved.
[75]
[76]
Next, with reference to FIG. 10, a heat dissipation path in a battery module according to an embodiment of the present invention will be described.
[77]
10 is a schematic diagram showing a path in which cooling is performed in a battery module according to an embodiment of the present invention.
[78]
Referring to FIG. 10, heat generated in the battery cell 10 moves along an arrow, thereby cooling the battery module.
[79]
That is, the heat generated by the battery cell 10 largely moves along two paths. One path is a path leading to the wide side of the battery cell 10 --> cartridge 20 --> module case 110 --> TIM layer 300 --> heat sink 200 (first path ), and another path is the top and bottom of the battery cell 10 --> thermally conductive resin layer 30 --> module case 110 --> TIM layer 300 --> heat sink 200 It is the path leading to (the second path).
[80]
[81]
As described above, the battery module according to an embodiment of the present invention can realize efficient cooling by dissipating heat from the battery cell 10 through two paths, and furthermore, the thermally conductive resin layer 30 forming the second path is In addition to improving the cooling efficiency, the reliability of the product may be improved by ensuring that the battery cell 10 is well fixed within the cartridge 20.
[82]
In addition, in the battery module according to an embodiment of the present invention, by individually injecting a thermally conductive resin paste for each cell assembly constituting the battery module, the paste forming the thermally conductive resin layer 30 is applied very uniformly. In this way, it is possible to increase the holding force between the battery cell 10 and the cartridge 20 and maximize the thermal conductivity between the lower end of the battery cell 10 and the cartridge 20.
[83]
[84]
Meanwhile, a battery pack may be formed by stacking at least one battery module according to an embodiment of the present invention as described above, and the battery pack implemented in this way is also excellent It is possible to have cooling efficiency and product reliability.
[85]
[86]
Although the present invention in the above has been described by the limited embodiments and drawings, the present invention is not limited thereto, and the technical idea of ​​the present invention and the following will be described by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various modifications and variations are possible within the equal scope of the claims.
Claims
[Claim 1]
A module body including a cell assembly stack formed by stacking a plurality of cell assemblies and a module case accommodating the cell assembly stack; And a pair of heat sinks disposed above and below the module body to dissipate heat transferred from the module case. Including, the cell assembly, at least one battery cell; A cartridge accommodating the battery cell; And a pair of thermally conductive resin layers filling empty spaces formed between the upper end of the battery cell and the cartridge and between the lower end of the battery cell and the cartridge. Battery module comprising a.
[Claim 2]
The battery module according to claim 1, wherein the cartridge has a rectangular parallelepiped shape with both sides open, and the battery cell contacts an inner surface of the cartridge.
[Claim 3]
The battery module of claim 1, wherein the cartridge has a rectangular parallelepiped shape with both sides open, and an insulating sheet is interposed between the battery cell and an inner surface of the cartridge.
[Claim 4]
The battery module of claim 1, wherein the upper and lower ends of the battery cells are in contact with the thermally conductive resin layer.
[Claim 5]
The battery module according to claim 1, wherein the cartridge comprises an injection port for injecting a resin paste for forming the thermally conductive resin layer and a discharge port through which the injected resin is discharged.
[Claim 6]
The battery module of claim 5, wherein the injection hole is formed at a central portion of a lower surface of the cartridge, and the discharge port is formed at both ends of the lower surface of the cartridge in the longitudinal direction.
[Claim 7]
The battery module according to claim 5, wherein the injection hole is formed at a central portion of the upper surface of the cartridge, and the discharge hole is formed at both ends of the upper surface of the cartridge in the longitudinal direction.
[Claim 8]
The battery module of claim 1, wherein the battery module further comprises a pair of TIIM layers interposed between the module body and the heat sink.
[Claim 9]
A battery pack comprising at least one battery module according to any one of claims 1 to 8.