Battery pack for relieving internal pressure during thermal runaway

Abstract

A battery pack for removing internal pressure during thermal runaway according to one embodiment of the present invention includes one or more battery modules; and a case for accommodating the battery modules, the case including a vent hole for discharging gas from inside; and a vent tape attached to the case to cover the vent hole.

Description

Technical Field

[0001] The present invention relates to a battery pack, and more particularly, to a battery pack capable of effectively removing internal pressure during thermal runaway.

Background Art

[0002] Unlike non-rechargeable primary batteries, secondary batteries are rechargeable and are applied not only to portable devices but also to electric vehicles (EVs), hybrid electric vehicles (HEVs), etc. driven by an electric drive source.

[0003] Currently widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, etc. The operating voltage of such a unit battery cell, that is, a unit battery cell, is about 2.5V to 4.6V. Therefore, when a higher output voltage is required, a battery pack is configured by connecting a large number of battery cells in series. Also, depending on the charge and discharge capacity required for the battery pack, a large number of battery cells may be connected in parallel to form a battery pack. Therefore, the number of battery cells included in the above battery pack can be variously set according to the required output voltage or charge and discharge capacity.

[0004] When configuring a battery pack by connecting a large number of battery cells in series and parallel, after forming at least one battery cell, preferably a battery module composed of a large number of battery cells, at least one of such battery modules is used, and other components are added to configure a battery pack. Here, a battery module means a component in which a large number of battery cells are connected in series or parallel, and a battery pack means a component in which a large number of battery modules are connected in series or parallel to increase the capacity and output, etc.

[0005] Typically, in vehicle battery packs, multiple battery modules or battery module assemblies are arranged on the same plane to maintain structural stability.

[0006] Furthermore, in such battery packs, if overcharging occurs, a high amount of energy flows instantaneously, and the positive electrode material becomes chemically activated significantly due to overcharging or a short circuit. This can cause a rapid reaction with the electrolyte, generating a large amount of gas. As a result, the internal pressure and temperature of the battery pack can rise rapidly, potentially leading to an explosion.

[0007] Conventionally, as shown in Figure 1, when the battery pack 10 experiences thermal runaway, gas leaks out through the rubber seal gasket provided between the upper housing 1 and the lower housing 2. In such cases, the gas is not quickly expelled, which can cause deformation of the outer housing and damage to the seal, potentially leading to flames escaping from the battery pack. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a battery pack that can quickly remove internal pressure in the event of thermal runaway. [Means for solving the problem]

[0009] A battery pack for removing internal pressure during thermal runaway according to one embodiment of the present invention comprises one or more battery modules; and a case housing the battery modules; wherein the case includes vent holes for discharging gas from the inside; and vent tape attached to the case so as to cover the vent holes.

[0010] The case further includes a lower housing and an upper housing coupled to the upper side of the lower housing.

[0011] Preferably, the vent holes are located in the upper housing.

[0012] Furthermore, multiple vent holes will be provided.

[0013] Furthermore, the vent tape mentioned above includes a perforated line.

[0014] Furthermore, the above-mentioned cutting lines are positioned outside the vent holes.

[0015] Furthermore, the above-mentioned cutting lines are formed to surround the above-mentioned vent holes.

[0016] Furthermore, the above-mentioned cutting line may be circular in shape.

[0017] Furthermore, the above-mentioned cutting line may be in the shape of an arc.

[0018] A battery pack for removing internal pressure during thermal runaway according to another embodiment of the present invention comprises one or more battery modules; and a case housing the battery modules; wherein the case includes vent holes for discharging gas from the inside; gas discharge tubes communicating with the vent holes and extending from the case to the outside; and vent tape covering the ends of the gas discharge tubes.

[0019] The system further includes an extension portion positioned at the end of the gas discharge tube and extending outward from the end of the gas discharge tube.

[0020] Furthermore, the vent tape is attached to the expanded portion.

[0021] Furthermore, the vent tape may include a cut line, and the cut line may be positioned outside the inner circumferential surface of the gas discharge tube in the expanded portion.

[0022] Also, the cut-off line may be provided so as to surround the inner circumference of the gas discharge tube.

Advantages of the Invention

[0023] According to the battery pack of the present invention, an effect of quickly removing the internal pressure can be obtained during thermal runaway.

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram showing a conventional battery pack. [Figure 2] It is a diagram showing a battery pack according to the first embodiment of the present invention. [Figure 3] It is a detailed diagram showing part A in FIG. 2. [Figure 4] It is a diagram showing a cross-section of one side of the battery pack in FIG. 2. [Figure 5] It is a diagram showing an enlarged view of a vent tape in a battery pack for removing internal pressure during thermal runaway according to the second embodiment of the present invention. [Figure 6] It is a diagram showing an enlarged view of a vent tape in a battery pack for removing internal pressure during thermal runaway according to the third embodiment of the present invention. [Figure 7] It is a diagram showing an enlarged view of a vent tape in a battery pack for removing internal pressure during thermal runaway according to the third embodiment of the present invention. [Figure 8] It is a diagram showing that internal gas is discharged through a vent hole in FIG. 6. [Figure 9] It is a diagram showing that internal gas is discharged through a vent hole in FIG. 7. [Figure 10] It is a diagram showing a battery pack according to the fourth embodiment of the present invention. [Figure 11] It is a diagram showing a battery pack according to the fourth embodiment of the present invention.

Modes for Carrying Out the Invention

[0025] The advantages and features of the present invention, as well as methods for achieving them, will become apparent from the embodiments detailed with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be realized in various different forms, although these embodiments are provided for the complete disclosure of the present invention and to fully inform those skilled in the art of the invention of its scope, and the present invention should be defined by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known element structures, and well-known techniques are not specifically described to avoid ambiguity of the present invention. Throughout this specification, the same reference numerals refer to the same components.

[0026] In the drawings, thicknesses are enlarged to clearly represent multiple layers and regions. Similar parts are denoted by the same reference numerals throughout this specification. When a layer, membrane, region, plate, or other part is said to be "on top" of another part, this includes not only when it is "directly above" the other part, but also when there is another part in between. In contrast, when a part is said to be "directly above" another part, it means there is no other part in between. Similarly, when a layer, membrane, region, plate, or other part is said to be "below" another part, this includes not only when it is "directly below" the other part, but also when there is another part in between. In contrast, when a part is said to be "directly below" another part, it means there is no other part in between.

[0027] A battery pack for removing internal pressure during thermal runaway, according to a preferred embodiment of the present invention, will be described in detail below with reference to the attached drawings.

[0028] Figure 2 shows a battery pack according to one embodiment of the present invention, Figure 3 is a detailed view of portion A in Figure 2, and Figure 4 shows a cross-section of one side of the battery pack in Figure 2.

[0029] A battery pack 1000 for removing internal pressure during thermal runaway according to one embodiment of the present invention includes one or more battery modules 500 and a case 50 housing the battery modules 500, the case 50 including an upper housing 100 and a lower housing 200.

[0030] The battery module 500 housed in the battery pack 1000 comprises a plurality of battery cells (not shown), each of which may be, for example, a pouch-type battery cell. For example, the battery module 500 comprises a plurality of battery cells stacked on top of each other, and each battery cell has electrode leads at both its front and rear ends, with a positive electrode lead provided at the front end and a negative electrode lead at the rear end. The plurality of battery cells in the battery module 500 may be stacked so as to be electrically connected to each other. The battery cells are not limited to pouch-type battery cells, but may also be battery cells of other forms, such as prismatic battery cells, and multiple battery cells may be housed within the case of the battery module 500.

[0031] The above case 50 is for housing multiple battery modules 500 and includes an upper housing 100 and a lower housing 200, and further includes a gasket 400 between the upper and lower housings 100 and 200.

[0032] The lower housing 200 can accommodate multiple battery modules 500, and the upper housing 100 is connected to the upper side of the lower housing 200, forming an internal space inside the case 50 in which the battery modules 500 are housed.

[0033] The gasket 400, positioned between the upper housing 100 and the lower housing 200, is provided for sealing between the upper housing 100 and the lower housing 200, and is positioned over the entire joint between the upper and lower housings 100 and 200, forming a closed loop shape on a plane. The gasket material may be rubber or other materials.

[0034] In this invention, vent holes 110 are formed in the case 50. The vent holes 110 are for releasing gas generated inside the battery pack 1000 during thermal runaway, and Figures 2 and 3 show an example in which vent holes 110 are formed in the upper housing 100.

[0035] In battery packs, if overcharging occurs, a high amount of energy flows instantaneously, and the positive electrode material becomes chemically activated significantly due to overcharging or a short circuit. This can cause a rapid reaction with the electrolyte, generating a large amount of gas. As a result, the internal pressure and temperature of the battery pack can rise sharply, potentially leading to the battery pack exploding.

[0036] In this invention, when the battery pack 1000 experiences thermal runaway, the gas generated inside is discharged through the vent hole 110, thereby preventing deformation of the external housing and damage to the seal due to increased internal pressure. Figures 2 and 3 show an example in which the vent hole 110 is formed in the upper housing 100, but the vent hole 110 may also be formed in the lower housing 200.

[0037] Two or more vent holes 110 may be provided in the case 50, as shown in the figure.

[0038] Furthermore, a vent tape 300 is attached to the top of the vent hole 110. The vent tape 300 is attached to the case 50 or upper housing 100 so as to cover the vent hole 110, and the vent tape 300 has a larger surface area than the vent hole 110 and is attached to the case 50 or upper housing 100 by adhesive applied to its back surface.

[0039] Normally, the vent tape 300 seals the inside of the case 50 from the outside and prevents foreign matter from entering. However, in the event of thermal runaway of the battery pack, when a certain pressure is generated due to the rise in internal pressure of the battery pack 1000, the vent tape 300 loses its adhesive strength. As a result, the vent tape 300 separates from the case 50 or the upper housing 100, and internal gas is discharged through the vent hole 110.

[0040] Conventionally, when a battery pack overheats, gas leaks through the gasket between the upper and lower housings, preventing the gas from being quickly expelled and causing deformation of the outer housing and damage to the seals. However, in the present invention, when a battery pack overheats, if the internal pressure rises due to the gas generated inside the battery pack 1000 and exceeds a certain pressure, the vent tape 300 separates from the case 50 or the upper housing 100, and the internal gas is expelled through the vent hole 110, quickly removing the internal pressure. As a result, the internal pressure is removed in the initial stages of overheating, preventing flames from being generated outside the battery pack.

[0041] Next, a battery pack for removing internal pressure during thermal runaway according to a second embodiment of the present invention will be described. Figure 5 is a magnified view of the vent tape in the battery pack for removing internal pressure during thermal runaway according to a second embodiment of the present invention.

[0042] The difference between the second embodiment and the first embodiment is that the vent tape 300 has a perforated line 310 formed on it.

[0043] In this embodiment, the cutting line 310 is circular in shape and is formed on the vent tape 300 to surround the vent hole 110 from the outside. The diameter of the cutting line may be the same as the diameter of the vent hole 110, or it may be larger.

[0044] Specifically, the cutting line 310 includes a plurality of cut holes 311 spaced apart from each other, as shown in the figure, and each cut hole 311 is arc-shaped, forming part of a circle. Therefore, the cut holes 311 come together to form a single circular shape.

[0045] In a second embodiment of the present invention, the case 50 normally isolates the inside from the outside and prevents foreign matter from entering. However, in the event of thermal runaway of the battery pack, when the internal pressure rises due to the gas generated inside the battery pack 1000 and exceeds a certain pressure, part or all of the cut line 310 portion of the vent tape 300 is cut off, separating the vent tape 300 from the case 50 or upper housing 100. The internal gas is then discharged through the vent hole 110 and the separated cut line portion, thereby removing the internal pressure.

[0046] Furthermore, in the second embodiment of the present invention, the exhaust pressure of the exhaust gas can be adjusted by adjusting the width of each cut hole 311 that constitutes the cut line 310, the spacing between the cut holes 311, and so on.

[0047] Specifically, increasing the spacing between the cut holes 311 increases the reference pressure at which exhaust gas is discharged, while decreasing the spacing between the cut holes 311 decreases the reference pressure at which exhaust gas is discharged.

[0048] Furthermore, by increasing the width of the cut-out hole 311, the reference pressure at which exhaust gas is discharged can be lowered, and by decreasing the width of the cut-out hole 311, the reference pressure at which exhaust gas is discharged can be increased.

[0049] The other configurations and effects are the same as in the first embodiment, so a detailed explanation will be omitted.

[0050] Next, a battery pack for removing internal pressure during thermal runaway according to a third embodiment of the present invention will be described. Figures 6 and 7 are enlarged views of the vent tape in the battery pack for removing internal pressure during thermal runaway according to the third embodiment of the present invention, Figure 8 shows that internal gas is discharged through the vent hole in Figure 6, and Figure 9 shows that internal gas is discharged through the vent hole in Figure 7.

[0051] The third embodiment differs from the second embodiment in that the cutting line 310 of the vent tape 300 is arc-shaped.

[0052] In the third embodiment, unlike the second embodiment, the cutting line 310 is not circular but arc-shaped, and Figures 6 and 7 show an example where the cutting line 310 is semicircular.

[0053] Figure 6 shows an example where the cut line 310 is positioned on the lower side of the vent hole 110, and Figure 7 shows an example where the cut line 310 is positioned on the upper side of the vent hole 110.

[0054] In the third embodiment, when the battery pack experiences thermal runaway, if the internal pressure rises due to the gas generated inside the battery pack 1000 and exceeds a certain pressure, the portion of the vent tape 300 with the cut line 310 is cut off. If the cut line 310 is positioned on the lower side of the vent hole 110 as shown in Figure 6, the gas that has passed through the vent hole 110 is discharged downward (see Figure 8). If the cut line 310 is positioned on the upper side of the vent hole as shown in Figure 7, the gas that has passed through the vent hole 110 is discharged upward (see Figure 9).

[0055] Therefore, in the third embodiment of the present invention, the cut line 310 is arc-shaped, and there is an advantage that the direction of exhaust gas discharge can be adjusted by changing the formation position of the cut line 310. Accordingly, the cut line 310 may be located on the left or right side of the vent hole 110, and if there are two vent holes 110 as shown in the figure, the cut line 310 located in the left vent hole 110 may be located on the left (or right) side of the vent hole 110, and the cut line 310 located in the right vent hole 110 may be located on the right (or left) side of the vent hole 110.

[0056] In Figures 6 and 7, the cutting lines are semicircular, but they may also be smaller than a semicircle or larger than a semicircle.

[0057] Next, a battery pack for removing internal pressure during thermal runaway according to a fourth embodiment of the present invention will be described. Figures 10 and 11 show the battery pack according to the fourth embodiment of the present invention.

[0058] The fourth embodiment differs from the embodiments described above in that it is provided with a gas discharge tube 150 that communicates with the vent hole 110, and the vent tape 300 is positioned to cover the end of the gas discharge tube 150.

[0059] Specifically, the gas discharge tube 150 is connected from the case 50 or upper housing 100 to the vent hole 110 and extends outward by a certain length. One end of the gas discharge tube 150 is connected to the vent hole 110, and the other end of the gas discharge tube 150 is positioned to protrude outward by a certain length, with an extension portion 170 provided at the other end.

[0060] In this embodiment, the expansion portion 170 is flat and is positioned at the other end of the gas discharge tube 150, so as to expand outward from the outer surface of the gas discharge tube 150.

[0061] A communication hole 171 is formed in the center of the expanded portion 170, which communicates with the gas discharge tube 150. The diameter of the communication hole 171 may be the same as or larger than the inner diameter of the gas discharge tube 150.

[0062] A vent tape 300 is attached to this expanded portion 170. The vent tape 300 is provided on the expanded portion 170 so as to cover the end of the gas discharge tube 150 and the communication hole 171.

[0063] In the fourth embodiment, when the battery pack experiences thermal runaway and the internal pressure rises due to gas generated inside the battery pack 1000, the gas is guided through the vent hole 110 to the gas discharge tube 150, and the other end of the gas discharge tube 150 is separated from the vent tape 300 provided on the expansion portion 170, thereby discharging the gas to the outside and removing the internal pressure.

[0064] In this embodiment, the gas discharge tube 150 may be connected to the case 50 or upper housing 100 so as to extend upward, downward, left, or right, and the gas discharge tube 150 may extend in a straight line or have a bent portion that is bent in one direction, or may be formed to bend in one direction.

[0065] Thus, in the fourth embodiment, the internal gas is guided and discharged by a gas discharge tube 150 connected to the vent hole 110, and the direction of gas discharge can be adjusted by adjusting the direction in which the gas discharge tube 150 extends from the case 50 or the upper housing 100.

[0066] Furthermore, in the fourth embodiment, the vent tape 300 may further include the cut lines 310 in the second and third embodiments (see Figure 11).

[0067] In this case, the cut line 310 may be positioned outside the inner circumferential surface of the gas discharge tube 150 in the expanded portion 170, or it may be positioned in the expanded portion 170 so as to surround the inner circumference of the gas discharge tube 150 (the cross-sectional hole or communication hole 171 of the moving passage). Also, the cut line 310 may be circular or arc-shaped, as in the second and third embodiments.

[0068] The other configurations and effects are the same as those of the embodiments described above, so a detailed explanation will be omitted.

[0069] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be implemented in various ways by persons with ordinary skill in the art to which the present invention belongs, without departing from the spirit of the invention. [Industrial applicability]

[0070] According to the present invention, it is possible to provide a battery pack that can quickly remove internal pressure in the event of thermal runaway. [Explanation of Symbols]

[0071] 1 Upper housing 2 Lower housing 10 Battery Packs 50 cases 100 Upper Housing 110 Benthole 150 Gas discharge tube 170 Expansion section 171 Communication hole 200 Lower Housing 300 Vent Tape 310 Cut line 311 Cut holes 400 Gasket 500 Battery Modules 1000 Battery Pack

Claims

1. One or more battery modules; and, A case for housing the aforementioned battery module; The aforementioned case is, Vent holes for releasing gas from the inside; and, A vent tape that is attached to the case so as to cover the vent hole; Includes, The vent holes are provided on the side of the case, The aforementioned vent tape includes a cut line, The aforementioned cutting line is located outside the vent hole, The aforementioned cutting line is arc-shaped and is positioned on the lower or upper side of the vent hole, and is a battery pack for removing internal pressure during thermal runaway.

2. The aforementioned case is, Lower housing; and, An upper housing connected to the upper side of the lower housing; A battery pack for removing internal pressure during thermal runaway, further comprising the battery pack described in claim 1.

3. The vent hole is located in the upper housing and is part of the battery pack for removing internal pressure during thermal runaway as described in claim 2.

4. The battery pack for removing internal pressure during thermal runaway, according to claim 3, wherein a plurality of vent holes are provided.

5. The aforementioned cut line is formed to surround the vent hole, a battery pack for removing internal pressure during thermal runaway as described in claim 1.

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