Battery module with potting resin leakage prevention function and battery pack including the same

Abstract

The present invention relates to a battery module having a function of preventing leakage of a potting resin and a battery pack including the same, and more particularly to a battery module including the same, the battery module including a plurality of battery cells, an upper case for accommodating upper portions of the battery cells, the upper case being composed of a plurality of first side plates and an upper plate connecting upper ends of the first side plates, and a lower case for accommodating lower portions of the battery cells, the upper plate being formed with a plurality of second side plates and a lower plate connecting lower ends of the second side plates, the upper plate being provided with a plurality of through holes,

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2021-0152198 filed on November 8, 2021, and Korean Patent Application No. 2022-0131070 filed on October 13, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module having a function of preventing leakage of potting resin and a battery pack including the same. Specifically, the present invention relates to a battery module having a function of preventing leakage of potting resin, which allows for rapid injection of potting resin without causing it to leak out of the case when the potting resin is injected, and further relates to a battery pack including the same, which can simplify the manufacturing process of the battery module. [Background technology]

[0003] Recently, the demand for secondary batteries that can store electrical energy produced by the development of alternative energy sources due to air pollution caused by the use of fossil fuels and energy depletion has increased. Rechargeable secondary batteries are widely used in various fields, such as mobile devices, electric vehicles, hybrid electric vehicles, and industrial robots.

[0004] Secondary batteries are used as energy sources for various electronic devices that are essential in modern society, and the required capacity is increasing due to the increasing use and complexity of mobile devices and the development of electric vehicles, etc. To meet user demands, small devices are equipped with multiple battery cells, while automobiles and other devices use battery modules that electrically connect multiple battery cells or battery packs that include multiple such battery modules.

[0005] A battery module typically has a structure in which a number of battery cells are housed inside a case that is separated into an upper and lower section, thereby protecting the battery cells from external impacts and preventing moisture penetration or the intrusion of various foreign objects.

[0006] Meanwhile, the importance of safety is increasing due to the risk of fires occurring inside battery cells due to external impacts such as overheating or overcharging of battery cells. Therefore, a technology of potting the battery cells with silicone liquid is being implemented to prevent thermal runaway and heat transfer phenomena that may occur in the event of a chain reaction of fires.

[0007] However, if the viscosity of the potting resin is low, it may leak into the gaps in the module case, causing other problems. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 2021-0067663 Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a battery module having a structure that prevents leakage of potting resin outside the case even when the viscosity of the potting resin is low.

[0010] Another object of the present invention is to provide a battery module that can simplify the manufacturing process of the battery module.

[0011] Another object of the present invention is to provide a battery module having a structure that allows potting resin to be quickly and uniformly distributed to each battery cell when it is poured into the case. [Means for solving the problem]

[0012] To achieve the above object, the battery module according to the present invention includes an upper case (100) for accommodating a plurality of battery cells (B), a plurality of first side plates (110) and an upper plate (120) connecting the upper ends of the first side plates (110), and a lower case (200) for accommodating the lower parts of the battery cells (B), and a plurality of second side plates (210) and a lower plate (220) connecting the lower ends of the second side plates (210), and the upper case (100) is characterized in that the upper plate (120) is provided with a plurality of through holes.

[0013] In addition, in the battery module according to the present invention, the through holes include a first through hole (121) surrounding the upper part of the battery cell (B) and exposing one end of the battery cell (B) to the outside, a second through hole (122) for injecting potting resin, and a third through hole (123) for discharging air inside the upper case (100) and the lower case (200) when filling the resin.

[0014] In addition, in the battery module according to the present invention, the cross-sectional areas of the first through-hole (121), the second through-hole (122), and the third through-hole (123) decrease in this order.

[0015] In addition, in the battery module according to the present invention, the first through-hole (121) includes a first upper through-hole (121a) smaller than the outer diameter of the battery cell (B) and a first lower through-hole (121b) larger than the outer diameter of the battery cell (B), and a first space portion (S1) is provided below the upper plate (120).

[0016] In addition, in the battery module according to the present invention, a first sealing member (111) is provided at the lower end of the first side plate (110) and protrudes by a predetermined length.

[0017] In addition, in the battery module according to the present invention, the first sealing member (111) is integrated with the upper case (100) by double injection molding.

[0018] In addition, in the battery module according to the present invention, the lower plate (220) is provided with a fourth through-hole (221) that surrounds the lower portion of the battery cell (B) and exposes the other end of the battery cell (B) to the outside, and a second space portion (S2) is provided at the upper portion of the lower plate (220).

[0019] In addition, the battery module according to the present invention is characterized in that a second sealing member (222) is provided on a partial area of ​​the inner surface of the fourth through hole (221).

[0020] In the battery module according to the present invention, the second sealing member (222) is in close contact with the lower outer circumferential surface of the battery cell (B).

[0021] In addition, in the battery module according to the present invention, the second sealing member (222) is integrated with the lower case (200) by double injection molding.

[0022] In the battery module according to the present invention, the second sealing member (222) is recessed into the inner surface of the fourth through hole (221).

[0023] In the battery module according to the present invention, the second side plate (210) is provided at its upper end with a recess (211) in which the first sealing member (111) is seated.

[0024] In addition, in the battery module according to the present invention, a first sealing member protruding a predetermined length is provided at the upper end of the second side plate (210), and a groove portion in which the first sealing member is seated is provided at the lower end of the first side plate (110).

[0025] The present invention is also characterized by a battery pack including the above-mentioned battery module.

[0026] The present invention is also characterized by a device equipped with the above-mentioned battery pack. [Effects of the Invention]

[0027] As described above, the battery module having a potting resin leakage prevention function and the battery pack including the same according to the present invention have the advantage that a second sealing member is provided on the inner surface of the fourth through hole of the lower case, thereby preventing the injected resin from flowing to the bottom of the case even if the viscosity of the resin is low.

[0028] In addition, the battery module having a potting resin leakage prevention function and the battery pack including the same according to the present invention have a first sealing member and a recessed groove portion at the portion where the lower case and the upper case are joined, which has the advantage of preventing leakage of the injected resin to the side of the case even if the viscosity of the resin is low.

[0029] In addition, the battery module having a potting resin leakage prevention function and the battery pack including the same according to the present invention have an advantage that the potting resin can easily flow into the case because the upper case has a through-hole for air exhaustion.

[0030] Furthermore, according to the battery module having a potting resin leakage prevention function and the battery pack including the same according to the present invention, the first sealing member and the second sealing member are integrated by double injection molding, which has the advantage of contributing to simplifying the manufacturing process of the battery module. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view of a battery module according to a preferred embodiment of the present invention; [Figure 2] 1 is a plan view of a battery module according to a preferred embodiment of the present invention; [Figure 3] 1 is a bottom perspective view of a battery module according to a preferred embodiment of the present invention; [Figure 4] FIG. 2 is a perspective view taken along the line AA in FIG. [Figure 5] FIG. 5 is a perspective view of the battery cell shown in FIG. 4 with no battery cells attached. [Figure 6] 2 is a perspective view illustrating an internal structure of an upper case of a battery module according to a preferred embodiment of the present invention; FIG. [Figure 7] 1 is a perspective view showing a state in which battery cells of a battery module are housed in a lower case according to a preferred embodiment of the present invention; [Figure 8] 2 is a perspective view illustrating an internal structure of a lower case of a battery module according to a preferred embodiment of the present invention; FIG. 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] Furthermore, throughout the specification, the meanings of "upper" and "lower" can be understood as the concepts of "lower" and "upper" or "one side" and "other side" depending on the installation direction.

[0035] Hereinafter, a battery module having a function of preventing leakage of potting resin according to the present invention and a battery pack including the same will be described with reference to the accompanying drawings.

[0036] FIG. 1 is a perspective view of a battery module according to a preferred embodiment of the present invention, FIG. 2 is a plan view of a battery module according to a preferred embodiment of the present invention, and FIG. 3 is a bottom perspective view of a battery module according to a preferred embodiment of the present invention.

[0037] The battery module according to the present invention will be described with reference to FIGS. 1 to 3. The battery module includes a plurality of battery cells B and a case for housing the battery cells B, the case having a substantially hexahedral outer shape.

[0038] Here, the battery cells B may be cylindrical battery cells. Although the drawing shows four battery cells B, this is merely an example and the number of battery cells B may be increased or decreased.

[0039] Meanwhile, the cylindrical battery cell B includes an electrode assembly, an insulating member, a positive electrode lead wire, a cap assembly, and a battery can containing these. The electrode assembly may be a jelly-roll type electrode assembly in which a separator is interposed between long sheet-like positive and negative electrodes 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 then attached to each other.

[0040] Generally, a positive electrode lead attached to the upper end of the electrode assembly is electrically connected to the cap assembly, and a negative electrode lead attached to the lower end of the electrode assembly is connected to the bottom of the battery can. Meanwhile, an insulating member may be located on the upper part of the electrode assembly, and this insulating member serves to insulate the electrode assembly from the cap assembly.

[0041] The cap assembly is located on top of the insulating member, is electrically connected to the positive electrode lead wire attached to the upper end of the electrode assembly, and is coupled to the upper open end of the battery can, thereby sealing the electrode assembly housed inside the battery can.

[0042] Specifically, the cap assembly may include a current interrupting member, a current interrupting gasket, a safety vent, and a top cap stacked in order from the bottom up, and a crimping gasket and a welding holder may be positioned on the outer edges of the safety vent and the top cap.

[0043] The case may be composed of an upper case 100, the upper and lower parts of which can be separated from each other, and a lower case 200 located below the upper case 100. Specifically, the upper case 100 is for accommodating a portion of the upper part of the battery cell B, and is composed of a number of first side plates 110 and an upper plate 120 connecting the upper ends of the first side plates 110.

[0044] The upper plate 120 is provided with a number of through holes, more specifically, a first through hole 121, a second through hole 122, and a third through hole 123. The first through hole 121 surrounds and supports a portion of the upper part of the battery cell B, and allows one end, i.e., the top cap of the battery cell B, to be exposed to the outside. Therefore, it is preferable that the number of first through holes 121 is the same as the number of battery cells B to be accommodated.

[0045] The second through-holes 122 are through-holes for injecting potting resin to fix the battery cells B inside the upper case 100 and the lower case 200. A plurality of second through-holes 122 may be formed depending on the number of battery cells B to be accommodated and the size of the battery module. However, if there is only one second through-hole 122, it is preferable that it be located in the center of the upper case 100 so that the potting resin can move to the outer surface of each battery cell B in as short a time as possible.

[0046] The third through-hole 123 is for guiding the discharge of internal air when filling a potting resin.

[0047] Here, the potting resin is used to coat the periphery of the battery cell to control thermal runaway and heat transfer phenomena that may occur in the event of a chain reaction of fires among the battery cells, and to fix the case and the battery cell B together. For example, the potting resin may be silicon mixed with a phase change material (PCM).

[0048] Meanwhile, the cross-sectional areas of the first through hole 121, the second through hole 122, and the third through hole 123 decrease in this order. That is, it is preferable that the first through hole 121 is the largest and the third through hole 123 is the smallest.

[0049] The lower case 200, which is located below the upper case 100 and fixed to the upper case 100, is for accommodating a portion of the lower part of the battery cell B. Specifically, the lower case 200 may be composed of a plurality of second side plates 210 and a lower plate 220 that connects the lower ends of the second side plates 210 and has a plurality of fourth through holes 221 formed therein.

[0050] Here, the fourth through-holes 221 are located on the opposite side of the top cap of the battery cell B, that is, at the location where the bottom of the battery cell B is exposed, and therefore, it is preferable that the number of fourth through-holes 221 is the same as the number of battery cells B to be accommodated.

[0051] Fig. 4 is a perspective view cut along line AA in Fig. 1, Fig. 5 is a perspective view of Fig. 4 in a state where no battery cells are installed, Fig. 6 is a perspective view illustrating the internal structure of an upper case of a battery module according to a preferred embodiment of the present invention, Fig. 7 is a perspective view showing a state in which battery cells of a battery module according to a preferred embodiment of the present invention are housed in a lower case, and Fig. 8 is a perspective view illustrating the internal structure of a lower case of a battery module according to a preferred embodiment of the present invention.

[0052] The upper case and the lower case will be described in more detail with reference to these FIGS.

[0053] As described above, the upper case 100 includes the first through hole 121, the second through hole 122, and the third through hole 123, as well as the first sealing member 111 and the first space S1.

[0054] Here, the first through-hole 121 preferably comprises a first upper through-hole 121a and a first lower through-hole 121b, which will be described later.

[0055] The first space S1 is located below the upper plate 120 of the upper case 100, more specifically below the first lower through-hole 121b, and a resin is filled into the first space S1 to fix a portion of the battery cell B.

[0056] Of course, the potting resin that flows into the first space portion S1 can move to the second space portion S2 described below, and can also fill the gap between the upper outer surface of the battery cell B and the inner surface of the first lower through-hole 121b, and the gap between the lower outer surface of the battery cell B and the inner surface of the fourth upper through-hole 221a.

[0057] The first sealing member 111 may be provided along the lower end of the first side plate 110 of the upper case 100. Specifically, when viewed from the upper case 100, the first sealing member 111 protrudes downward by a predetermined length, and the material thereof is not particularly limited as long as it can function as a sealing member, such as silicone or rubber.

[0058] The first sealing member 111 is seated in a groove 211 of the lower case 200 (described later) and tightly adheres to the groove 211, thereby preventing the potting resin injected when fixing the battery cell B from leaking out.

[0059] Here, it is possible to manufacture the upper case 100 and the first sealing member 111 separately and then attach the first sealing member 111 to the upper case 100, but it is advantageous to manufacture the upper case 100 and the first sealing member 111 simultaneously by double injection molding in terms of bonding strength and process simplification.

[0060] 4 and 5, the first through-hole 121 preferably includes a first upper through-hole 121a that is smaller than the outer diameter of the battery cell B, and a first lower through-hole 121b that is located below the first upper through-hole 121a and is equal to or larger than the outer diameter of the battery cell B. This is because the top cap of the battery cell B can be exposed to the outside and electrically connected to a bus bar (not shown), and the battery cell B can be reliably prevented from jumping out of the upper case 100 through the first through-hole 121.

[0061] Next, the lower case 200 will be described in detail. A number of fourth through holes 221 each having an outer diameter equal to or larger than that of the battery cell B are formed in the lower plate 220 of the lower case 200, and second sealing members 222 are formed on a partial area of ​​the inner surface of the fourth through holes 221. This will be described in detail later.

[0062] Meanwhile, a second space S2 filled with potting resin is provided on the upper part of the lower plate 220 of the lower case 200. The second space S2 is filled with the potting resin that flows down through the first space S1, thereby fixing a portion of the battery cell B.

[0063] The second sealing member 222 is recessed into the inner surface of the fourth through hole 221, thereby coming into close contact with a portion of the lower outer peripheral surface of the battery cell B. In particular, the fourth through hole 221 may be composed of a fourth upper through hole 221a and a fourth lower through hole 221b located below the fourth upper through hole 221a. Here, the second sealing member 222 may be located in a portion or the entire area of ​​the fourth lower through hole 221b.

[0064] Potting resin is commonly used to secure battery cells housed in a case. However, if the viscosity of the resin injected is low, it can flow downward through the gap between the battery cell and the support wall, resulting in frequent leakage to the outside of the case.

[0065] However, in the present invention, since the second sealing member 222 is provided on the inner surface of the fourth through hole 221, leakage of the injected potting resin through the fourth through hole 221 can be fundamentally prevented.

[0066] Here, the second sealing member 222 may form a smooth single plane without protruding from the inner surface of the fourth through hole 221, but it is more preferable that the second sealing member 222 protrudes slightly from the inner surface.

[0067] That is, by fixing a portion of the lower outer peripheral surface of the battery cell B with the second sealing member 222, it is possible to prevent the potting resin from flowing downward, and it is advantageous to fill the second sealing member 222 with potting resin to fix the outer surface of the battery cell B and the inner surface of the fourth through hole 221.

[0068] Although it is possible to manufacture the lower case 200 and the second sealing member 222 separately and then attach the second sealing member 222 to the lower case 200, it is advantageous to manufacture the lower case 200 and the second sealing member 222 simultaneously by double injection molding in terms of bonding strength and process simplification.

[0069] Meanwhile, a groove portion 211 in which the first sealing member 111 is seated is formed at the upper end of the second side plate 210, and these first sealing member 111 and groove portion 211 can reliably ensure airtightness at the joining portion between the upper case 100 and the lower case 200.

[0070] As described above, the present invention has a structure in which potting resin is filled in the first space S1 of the upper case 100 and the second space S2 of the lower case 200, which allows the battery cell B to be securely fixed and also contributes to reducing the weight of the battery module.

[0071] For example, with reference to Figures 1 to 8, it has been described that the first sealing member 111 is provided in the upper case 100 and the groove portion 211 for accommodating the first sealing member 111 is provided in the lower case 200, but it is clear that, conversely, the groove portion can be formed in the upper case 100 and the first sealing member can be provided in the lower case 200.

[0072] The present invention may be a battery module containing the cylindrical battery cells described above. The battery module or a battery pack containing the battery module may be mounted in a device. For example, the device may be an electronic device including a large-capacity battery, such as an electric vehicle, a hybrid vehicle, or a plug-in hybrid electric vehicle.

[0073] Although specific portions of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific techniques are merely preferred embodiments and do not limit the scope of the present invention. It is possible to make various changes and modifications within the scope and technical ideas of the present invention, and it goes without saying that such changes and modifications are also included in the scope of the appended claims. [Explanation of symbols]

[0074] 100 Upper Case 110 1st side plate 111 First sealing member 120 Upper Plate 121 First Through Hole 121a First upper through hole 121b First lower through hole 122 Second Through Hole 123 Third Through Hole 200 Lower Case 210 2nd side plate 211 Concave groove part 220 Lower plate 221 4th Through Hole 221a 4th upper through hole 221b 4th lower through hole 222 Second sealing member B Battery cell S1 1st space S2 2nd space

Claims

1. A plurality of battery cells; an upper case including a plurality of first side plates and an upper plate connecting upper ends of the first side plates, the upper case configured to accommodate upper portions of the battery cells; a lower case configured to accommodate lower portions of the battery cells and including a plurality of second side plates and a lower plate connecting lower ends of the second side plates; Including, The upper plate of the battery module has a plurality of through holes, The through-hole is a first through-hole surrounding an upper portion of the battery cell and exposing one end of the battery cell to the outside; a second through hole for injecting a potting resin; a third through hole for discharging air from inside the upper case and the lower case when the potting resin is filled; a battery module including:

2. 2. The battery module of claim 1, wherein a cross-sectional area of ​​the first through hole, a cross-sectional area of ​​the second through hole, and a cross-sectional area of ​​the third through hole decrease in the order of the first through hole, the second through hole, and the third through hole.

3. The first through hole is a first upper through hole having a diameter smaller than an outer diameter of the battery cell; a first lower through hole having an outer diameter equal to or larger than the outer diameter of the battery cell; The battery module according to claim 1 , wherein a first space is provided below the upper plate.

4. The battery module according to claim 3 , wherein a first sealing member is provided at a lower end of the first side plate, the first sealing member protruding by a predetermined length.

5. The battery module of claim 4 , wherein the first sealing member is integrated with the upper case by double injection molding.

6. the lower plate includes a fourth through-hole surrounding a lower portion of the battery cell and exposing the other end of the battery cell to the outside; The battery module according to claim 1 , wherein a second space is provided above the lower plate.

7. The battery module of claim 6 , wherein a second sealing member is provided on a portion of an inner surface of the fourth through hole.

8. The battery module of claim 7 , wherein the second sealing member is in close contact with a lower outer peripheral surface of the battery cell.

9. The battery module of claim 8 , wherein the second sealing member is integrated with the lower case by double injection molding.

10. The battery module of claim 7 , wherein the second sealing member is recessed into an inner surface of the fourth through hole.

11. The battery module according to claim 4 , wherein an upper end of the second side plate is provided with a recessed groove in which the first sealing member is seated.

12. A first sealing member is provided at an upper end of the second side plate and protrudes by a predetermined length, The battery module according to claim 1 , wherein a lower end of the first side plate is provided with a recessed groove in which the first sealing member is seated.

13. A battery pack comprising a battery module described in any one of claims 1 to 12.

14. A device equipped with the battery pack described in claim 13.

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