Pouch-type battery cell with easy-to-cool structure and manufacturing method thereof

Abstract

The present invention relates to a pouch-type battery cell having an easily cooled structure and a manufacturing method thereof. Specifically, the present invention relates to a pouch-type battery cell including an electrode assembly having a pair of electrode tabs connected to it, and a case for housing the electrode assembly, wherein a pair of electrode leads connected to the pair of electrode tabs of the electrode assembly are fixed to the case, and a manufacturing method thereof.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2021-0120684 dated September 9, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a pouch-type battery cell with an easily cooled structure and a manufacturing method thereof. Specifically, the present invention relates to a pouch-type battery cell with an easily cooled structure in which both sides of the pouch case are made of metal material to increase cooling efficiency, and which can further increase safety by guiding gas to a desired location in the event of an accident, and a manufacturing method thereof. [Background technology]

[0003] With the rapid development of IT (Information Technology) and the proliferation of a wide variety of portable information and communication devices, the 21st century is evolving into a "ubiquitous society" in which high-quality information services are available regardless of time or place.

[0004] Lithium secondary batteries play an important role in the foundation of this ubiquitous society. Specifically, rechargeable lithium secondary batteries are widely used as a power source for wireless mobile devices, as well as for electric vehicles and hybrid electric vehicles, which are being proposed as a solution to air pollution caused by existing gasoline and diesel vehicles that use fossil fuels.

[0005] As described above, as devices to which lithium secondary batteries are applied become more diverse, lithium secondary batteries are being diversified to provide outputs and capacities suitable for the devices to which they are applied, and there is a strong demand for them to be lighter, thinner, shorter, and smaller.

[0006] Meanwhile, secondary batteries can be classified into cylindrical batteries, prismatic batteries, pouch-type battery cells, etc. Among them, pouch-type battery cells are attracting much attention because they can be stacked at a high density, have a high energy density per weight, are inexpensive, and are easily deformable.

[0007] A pouch-type battery cell has a structure in which an electrode assembly consisting of a positive electrode, a negative electrode, and a separator is housed in a battery case made of a laminate sheet together with an electrolyte, and the outer periphery of the battery case is sealed by heat sealing.

[0008] However, heat is inevitably generated during the charging and discharging process of pouch-type battery cells, and in some cases, thermal runaway can occur due to short circuits, thermal shock, insulation breakdown, etc. This can lead to serious accidents such as fires and explosions, so cooling is a very important factor in pouch-type battery cells.

[0009] As shown in Figure 1, the typical exterior shape of such a pouch-type battery cell has a bat ear section (right side of Figure 1) and a folding section (left side of Figure 1) where the terrace section is folded, and cooling through the folding section is not possible due to structural issues.

[0010] Meanwhile, in the case of a pouch-type battery cell, if gas continuously generates inside the battery cell due to overcurrent and overvoltage during charging and discharging, the sealed portion of one side of the battery case opens to release the gas, but this does not affect the electrode assembly through which the current flows, so the current for charging and discharging continues to flow through the electrode assembly. This causes continuous gas generation, which can lead to a rise in the battery temperature, resulting in fire and explosion. Furthermore, the gas explosion can occur in an undesired location, damaging the case. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-1401230 Summary of the Invention [Problem to be solved by the invention]

[0012] In order to solve the above problems, an object of the present invention is to provide a pouch-type battery cell having a structure that allows cooling through both sides of the pouch-type battery cell, and a manufacturing method thereof.

[0013] Another object of the present invention is to provide a pouch-type battery cell having a structure that can vent gas to a desired position or direction in the event of an event, and a method for manufacturing the same. [Means for solving the problem]

[0014] To achieve the above object, a pouch-type battery cell according to the present invention includes an electrode assembly having a pair of electrode tabs connected to one another, and a case for accommodating the electrode assembly, wherein a pair of electrode leads connected to the pair of electrode tabs of the electrode assembly are fixed to the case.

[0015] In the pouch-type battery cell according to the present invention, one side of the electrode lead is located inside the case, and the other side of the electrode lead protrudes to the outside.

[0016] In the pouch-type battery cell according to the present invention, the pair of electrode leads are positioned to face each other.

[0017] In the pouch-type battery cell according to the present invention, the pair of electrode leads are positioned so as to face in the same direction.

[0018] In addition, in the pouch-type battery cell according to the present invention, the case includes a lower case including a front plate, a rear plate, a bottom plate, and a pair of side plates, and an upper case located on top of the lower case.

[0019] In the pouch-type battery cell according to the present invention, the front plate, rear plate, bottom plate and upper case are made of a plastic material, and the pair of side plates are made of a thermally conductive material.

[0020] In the pouch-type battery cell according to the present invention, the thermally conductive material includes at least one of aluminum, magnesium, zinc, and copper.

[0021] In addition, in the pouch-type battery cell according to the present invention, the plastic material includes at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride.

[0022] In the pouch-type battery cell according to the present invention, the case may be provided with a notch so that the inside of the case may be broken when the pressure or temperature exceeds a predetermined value.

[0023] The present invention may also be a battery module in which a number of pouch-type battery cells according to the present invention are arranged, and a cooling device is positioned in close contact with each of the pair of side plates.

[0024] In addition, a method for manufacturing a pouch-type battery cell according to the present invention is characterized by including a first step of preparing an electrode assembly and a lower case, a second step of housing the electrode assembly in the lower case, and a third step of sealing the lower case housing the electrode assembly with an upper case.

[0025] In addition, in the method for manufacturing a pouch-type battery cell according to the present invention, the lower case includes a front plate, a rear plate, a bottom plate, and a pair of side plates, the upper case is located on top of the lower case, and in the first step, one side of the electrode lead is located inside the lower case and the other side of the electrode lead is injection molded so as to protrude outside the lower case.

[0026] In the method for manufacturing a pouch-type battery cell according to the present invention, the second step may further include the step of welding an electrode lead located inside the lower case to an electrode tab of the electrode assembly.

[0027] In the method for manufacturing a pouch-type battery cell according to the present invention, the upper case is made of a plastic material, and in the third step, the lower case and the upper case are fixed together by plastic welding. [Effects of the Invention]

[0028] As described above, the pouch-type battery cell having an easy-to-cool structure and the manufacturing method thereof according to the present invention have the advantages of not requiring thermally conductive resin because the sides of the case are flat, and having both sides made of metal, resulting in excellent heat dissipation.

[0029] Furthermore, according to the pouch-type battery cell and manufacturing method thereof of the present invention, the outer shape of the case is hexahedral, which minimizes unnecessary space when stacking multiple battery cells, thereby increasing energy density.

[0030] Furthermore, according to the pouch-type battery cell and manufacturing method of the present invention, by providing a notch in the case, gas can be discharged to a desired location in the event of an accident, which has the advantage of reducing the risk of secondary accidents. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a cross-sectional view of a pouch-type battery cell according to the prior art. [Figure 2] 1 is a perspective view of a pouch-type battery cell according to a first preferred embodiment of the present invention; [Figure 3] 1 is an exploded perspective view of a pouch-type battery cell according to a first preferred embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a lower case according to a first preferred embodiment of the present invention, viewed from above. [Figure 5]FIG. 10 is a perspective view of a pouch-type battery cell according to a second preferred embodiment of the present invention. [Figure 6] FIG. 10 is an exploded perspective view of a pouch-type battery cell according to a second preferred embodiment of the present invention. [Figure 7] 1 is a diagram showing an example of a battery module including battery cells according to a first preferred embodiment of the present invention. [Figure 8] 2 is another exemplary view of a battery module including battery cells according to the first preferred embodiment of the present invention; FIG. [Figure 9] 3 is a flowchart illustrating a method for manufacturing a battery cell according to a first preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person skilled in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0033] Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

[0034] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pouch-type battery cell having an easy-to-cool structure and a method for manufacturing the same according to the present invention will now be described with reference to the accompanying drawings.

[0035] First, the pouch-type battery cell will be described.

[0036] FIG. 2 is a perspective view of a pouch-type battery cell according to a first preferred embodiment of the present invention, FIG. 3 is an exploded perspective view of the pouch-type battery cell according to the first preferred embodiment of the present invention, and FIG. 4 is a cross-sectional view of the lower case of the first preferred embodiment of the present invention as viewed from above.

[0037] Referring to FIGS. 2 to 4, a first preferred embodiment of the present invention will be described. A pouch-type battery cell 100 includes a lower case 110, an upper case 120, and an electrode assembly .

[0038] The lower case 110 has a rectangular parallelepiped shape consisting of a rectangular front plate 111, a rear plate 112, a pair of side plates 113, and a bottom plate 114, and has a space inside to accommodate the electrode assembly.

[0039] A first electrode lead 111' and a second electrode lead 112' are arranged to face each other on the front plate 111 and the rear plate 112 of the lower case 110. Specifically, the front plate 111 is provided with a first electrode lead 111' connected to one electrode tab 132 constituting the electrode assembly 130, and the rear plate 112 is also provided with a second electrode lead 112' connected to the remaining electrode tab 132.

[0040] Here, it is preferable that the front plate 111, rear plate 112, and bottom plate 114 are made of a plastic material, and the side plate 113 is made of a heat-conductive material.

[0041] More specifically, the front plate 111, rear plate 112, and bottom plate 114 are not particularly limited as long as they are made of plastic material, but are preferably made of one or more of polypropylene, polyethylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride, and polypropylene, which has the best moisture-blocking effect, is more preferred.

[0042] The side plates 113 are preferably made of one or more conductive materials selected from the group consisting of aluminum, magnesium, zinc, and copper, and more preferably aluminum.

[0043] As described above, the sides of the conventional pouch case are not flat and require the application of a separate heat-conductive resin. In particular, the side where the sealing portion is bent cannot be cooled.

[0044] However, the present invention has flat sides, so it does not require thermally conductive resin, and its structure allows heat to be dissipated through both sides, resulting in excellent heat dissipation.Furthermore, the hexahedral shape of the case minimizes unnecessary space when stacking multiple battery cells, and also increases energy density.

[0045] Meanwhile, the first electrode lead 111' and the second electrode lead 112' located on the front plate 111 and the rear plate 112, respectively, are located inside the case so that one side is electrically connected to the electrode tab 132, and the other side protrudes to the outside so as to be connected to a bus bar, etc.

[0046] The notch 111″ of the front plate 111 is configured to induce preferential rupture when an event occurs, for example, when excessive gas is generated and the pressure or temperature rises above a certain value. Gas can be discharged to a desired location through the notch 111″, thereby reducing the risk of secondary accidents when an event occurs.

[0047] Although the drawings show a single notch 111" formed on the front plate 111, this is merely an example and the notch may be formed on the rear plate 112, and the position and number of notches may be changed as desired.

[0048] Next, the upper case 120 is disposed and fixed to the upper end of the lower case 110, i.e., along the edge of the lower case 110, and also has a rectangular flat plate shape. The upper case 120 is preferably made of the same material as the front plate 111 and rear plate 112 of the lower case 110, because plastic welding is advantageous for this purpose.

[0049] Next, we will explain the electrode assembly 130 housed in the lower case 110. The electrode assembly 130 includes a laminate 131 in which a separator is interposed between a positive electrode and a negative electrode, and an electrode tab 132 that protrudes outward by a predetermined length.

[0050] Specifically, the electrode assembly 130 may be, but is not limited to, a jelly-roll type electrode assembly in which long sheet-like positive and negative electrodes are interposed between a separator and then wound up, a stack type electrode assembly composed of unit cells in which rectangular positive and negative electrodes are stacked with a separator interposed between them, a stack folding type electrode assembly in which unit cells are wound up with a long separator film, or a lamination stack type electrode assembly in which unit cells are stacked with a separator interposed between them and attached to each other, etc. Since the above-mentioned electrode assemblies correspond to commonly known configurations, further detailed description will be omitted.

[0051] Next, a second preferred embodiment of the present invention will be described with reference to FIGS.

[0052] FIG. 5 is a perspective view of a pouch-type battery cell according to a second preferred embodiment of the present invention, and FIG. 6 is an exploded perspective view of the pouch-type battery cell according to the second preferred embodiment of the present invention.

[0053] The lower case 110 according to the second embodiment of the present invention comprises a front plate 111, a rear plate 112, a bottom plate 114, and a pair of side plates 113. In particular, a pair of electrode leads 111' is provided only on the front plate 111. Accordingly, a pair of electrode tabs 132 of the electrode assembly 130 are also arranged in one direction.

[0054] Here, the materials of the front plate 111, rear plate 112, bottom plate 114, upper case 120, and pair of side plates 113 are the same as those in the first embodiment, so a detailed description will be omitted.

[0055] Next, a battery module including battery cells according to a first preferred embodiment of the present invention will be described.

[0056] FIG. 7 is a view showing an example of a battery module including battery cells according to a first preferred embodiment of the present invention, and FIG. 8 is a view showing another example of a battery module including battery cells according to the first preferred embodiment of the present invention.

[0057] 7, a number of battery cells 100 are arranged vertically in a row, and the cooling devices 200 may be arranged on the upper and lower parts of the battery cells 100 so as to be in close contact with the side plates of the battery cells 100.

[0058] 8, a number of battery cells 100 are arranged in a horizontal direction. Here, the cooling devices 200 may be arranged on both sides of the battery cells 100 so as to be in close contact with the side plates of the battery cells 100.

[0059] It is apparent that the cooling device 200 can be any known cooling device such as a heat sink, a cooling plate, or a cooling duct.

[0060] Next, a description will be given of a method for manufacturing a battery cell according to the first embodiment. Figure 9 is a flowchart for explaining the method for manufacturing a battery cell according to the first preferred embodiment of the present invention.

[0061] A method for manufacturing a battery cell according to the present invention includes a first step of preparing an electrode assembly and a lower case, a second step of housing the electrode assembly in the lower case, and a third step of sealing the lower case housing the electrode assembly with an upper case.

[0062] Specifically, in the first step of preparing the electrode assembly and lower case, the front and rear plates of the lower case are made using a double injection method (insert injection molding) so that the electrode tabs can be integrated, and the metal side plates are made separately. Of course, the lower plate and upper case are also made.

[0063] Here, the front plate, rear plate, and lower plate may be integrally formed, in which case they are folded based on their respective boundary surfaces.

[0064] The front plate, rear plate, bottom plate, and pair of side plates thus prepared are connected to form a space with only the top open, preferably by plastic welding.

[0065] Of course, the method is not limited to the above, and the entire lower case may be made by a known double injection method such as insert injection molding.

[0066] In the second step of housing the electrode assembly in the lower case, the electrode assembly is housed in the space of the lower case, and the electrode leads protruding into the space of the lower case are connected to the electrode tabs of the electrode assembly by known means such as welding.

[0067] Finally, in the third step of sealing the lower case housing the electrode assembly with the upper case, welding, preferably plastic welding, can be used, but is not limited to this.

[0068] Meanwhile, the notch 111'' of the front plate 111 may be formed separately after the front plate 111 is completed, or may be formed integrally with the front plate 111 during double injection.

[0069] Furthermore, since the upper case 120 and the lower case 110 must be tightly sealed, it is recommended to enhance safety and moisture barrier properties by forming a coating layer on the upper and lower sides, including the joint area, after plastic welding using a known coating agent with excellent flame resistance or moisture barrier properties, etc. Of course, in the case of the lower case, it is clear that a coating layer can be formed after insert injection molding.

[0070] Those skilled in the art will appreciate that various applications and modifications within the scope of the present invention will be possible based on the above content. [Explanation of symbols]

[0071] 100 battery cells 110 Lower Case 111 Front Plate 111' First electrode lead 111" notch 112 Rear plate 112' Second electrode lead 113 Side Plate 114 Bottom plate 120 Upper Case 130 Electrode assembly 131 Laminate 132 Electrode tab 200 Cooling device 300 battery modules

Claims

1. an electrode assembly in which a pair of electrode tabs are connected; a case that houses the electrode assembly, A pair of electrode leads connected to a pair of electrode tabs of the electrode assembly are fixed to the case, The case includes a lower case including a front plate, a rear plate, a bottom plate, and a pair of side plates, and an upper case located above the lower case, the front plate, the rear plate, the bottom plate, and the upper case are made of a plastic material, and the pair of side plates are made of a metal material; the lower case and the upper case form a sealed space, A cooling device is positioned in close contact with the pair of side plates, A pouch-type battery cell, wherein the case has a notch so that the inside of the case is broken when the pressure or temperature exceeds a predetermined value.

2. The pouch-type battery cell according to claim 1 , wherein one side of the electrode lead is located inside the case and the other side of the electrode lead protrudes to the outside.

3. The pouch-type battery cell according to claim 2 , wherein the pair of electrode leads are positioned to face each other.

4. The pouch-type battery cell according to claim 2 , wherein the pair of electrode leads are positioned so as to face in the same direction.

5. The pouch-type battery cell according to claim 1 , wherein the metal material includes at least one of aluminum, magnesium, zinc, and copper.

6. 2. The pouch-type battery cell according to claim 1, wherein the plastic material comprises one or more of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride.

7. A battery module comprising a large number of pouch-type battery cells according to any one of claims 1 to 6 arranged therein, and the cooling device being positioned in close contact with each of the pair of side plates.

8. A method for manufacturing the pouch-type battery cell according to any one of claims 1 to 6, a first step of preparing an electrode assembly and a lower case; a second step of housing the electrode assembly in the lower case; a third step of sealing the lower case, in which the electrode assembly is housed, with an upper case; The method for manufacturing a pouch-shaped battery cell, wherein the notch is formed during the first step or after the first step and before the second step.

9. the lower case includes a front plate, a rear plate, a bottom plate, and a pair of side plates, and the upper case is located above the lower case; 9. The method of claim 8, wherein in the first step, one side of the electrode lead is positioned inside the lower case and the other side of the electrode lead is injection molded so as to protrude outside the lower case.

10. 10. The method of claim 9, wherein the second step further comprises welding the electrode lead located inside the lower case to the electrode tab of the electrode assembly.

11. The upper case is made of a plastic material, The method of manufacturing a pouch-type battery cell according to claim 9 , wherein in the third step, the lower case and the upper case are fixed together by plastic welding.

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