Battery module and battery pack including same

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked; a module frame that houses the battery cell stack; and a rupture sheet formed between the battery cell stack and the module frame, the rupture sheet including a shape memory alloy (SMA).

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0020768 dated February 17, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module having improved stability and a battery pack including the same. [Background technology]

[0003] As technological development and demand for mobile devices increases, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting much attention not only for mobile devices such as mobile phones, digital cameras, notebooks, and wearable devices, but also as an energy source for power devices such as electric bicycles, electric cars, and hybrid electric cars.

[0004] Small mobile devices use one, two, three, or four battery cells per device, whereas medium to large devices such as automobiles require high output and large capacity. Therefore, medium to large battery modules, which electrically connect multiple battery cells, are used.

[0005] Since it is preferable that medium- to large-sized battery modules are manufactured with small size and weight, prismatic batteries, pouch-shaped batteries, etc., which can be stacked with high integration and have a small weight relative to their capacity, are mainly used as battery cells for medium- to large-sized battery modules. Such battery modules have a structure in which a number of cell assemblies, each including a plurality of unit battery cells, are connected in series to obtain high output. The battery cells include positive and negative electrode current collectors, separators, active materials, electrolytes, etc., and can be repeatedly charged and discharged through electrochemical reactions between the components.

[0006] Meanwhile, in recent years, as the need for large-capacity structures has increased, including the use of batteries as energy storage sources, there has been an increasing demand for multiple battery modules in which multiple secondary batteries are connected in series and / or parallel, and for multi-module battery packs in which the battery modules are assembled.

[0007] In addition, when configuring a battery pack by connecting multiple battery cells in series / parallel, a common method is to first configure a battery module consisting of at least one battery cell, and then use this at least one battery module to add other components to configure the battery pack.

[0008] FIG 1 is a view showing a burst sheet included in a conventional battery module. FIG 2 is a view showing an enlarged view of part A in FIG 1. FIG 3 is a view showing an enlarged view of part B in FIG 2. Referring to FIGS. 1 to 3, a burst sheet 10 of a conventional battery module may include a plurality of venting portions 11, and the venting portions 11 may include a rupture portion 15. In addition, the rupture portion 15 may be formed in a notch shape as shown in FIG 3.

[0009] More specifically, the rupture sheet 10 may have a venting portion 11 formed as shown in Fig. 2, and the rupture portion 15 may be formed in a state where it is connected to the rupture sheet 10 without being cut. In this case, when venting of gas inside the battery cell occurs, the gas is discharged to the outside, and the pressure increases to cut the notch shape along the cutting line CC' in Fig. 3. Therefore, when the rupture portion 15 ruptures, the venting portion 11 of the rupture sheet 10 forms a venting hole, and the gas inside the battery cell is vented to the outside.

[0010] However, the burstable sheet 10 of the conventional battery module must be formed with a very thin thickness because the notch shape must be cut along the cutting line CC' in Fig. 3 when venting gas inside the battery cell. In addition, even if gas venting is not occurring inside the battery cell, the conventional burstable sheet 10 is likely to be damaged and the burstable portion 15 may be cut off due to external vibration and impact during use of a general battery module. In this case, even if venting does not occur inside the battery cell, the internal structure of the battery module may be exposed to the outside due to the formation of the vent hole, which may reduce stability.

[0011] Therefore, there is a need for a new structure that can improve the stability of the battery module by rupturing sheet 10 only when gas in the battery cell is vented, thereby venting the gas inside the battery cell, and not rupturing sheet 10 when the battery module is in normal use. Summary of the Invention [Problem to be solved by the invention]

[0012] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a battery module capable of forming a vent hole only when venting gas inside the battery module, and a battery pack including the same.

[0013] However, the problems that the present invention is intended to solve are not limited to those mentioned above, and problems not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0014] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked; a module frame that houses the battery cell stack; and a rupture sheet formed between the battery cell stack and the module frame, the rupture sheet including a shape memory alloy (SMA).

[0015] The module frame may have a plurality of holes formed therein, and portions of the rupture sheet corresponding to the positions of the holes may include the shape memory alloy.

[0016] The burst sheet includes a plurality of burst layers; and between The burst induction member may be formed of the shape memory alloy.

[0017] The rupture inducing member may be formed at a portion of the rupture sheet corresponding to a position of a hole of the module frame.

[0018] When gas is vented from the battery module, the rupture inducing member expands, and the rupture layer is deformed as the rupture inducing member expands, forming a vent hole on the rupture sheet.

[0019] The rupture inducing member may expand as the shape memory alloy expands.

[0020] The venting hole may be formed in a plurality of holes.

[0021] The plurality of venting holes may be formed in portions of the rupturable sheet corresponding to the positions of the holes, and the plurality of venting holes formed in the portions of the rupturable sheet corresponding to the positions of the holes may form a venting portion.

[0022] The rupture inducing member may include a member that expands when a temperature of 100 degrees or more is applied to the rupture inducing member.

[0023] The burst sheet may be formed between an upper portion of the battery cell stack and the module frame.

[0024] A battery pack according to yet another embodiment of the present invention includes the battery module. Effect of the Invention

[0025] In a battery module according to one embodiment of the present invention, no venting holes are formed during normal operation of the battery module, but venting holes are formed on the burst sheet only in the case of gas venting inside the battery module, thereby improving the stability of the battery module.

[0026] In addition, since no vent holes are formed during normal use of the battery module, the possibility of exposure and damage to the inside of the battery module is minimized, and deterioration of the performance of the battery module can be minimized.

[0027] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Brief description of the drawings]

[0028] [Figure 1] 1 is a diagram showing a burst sheet included in a conventional battery module. [Diagram 2] 2 is an enlarged view of part A in FIG. 1. [Diagram 3] 3 is an enlarged view of part B in FIG. 2. [Figure 4] 1 is an exploded perspective view of a battery module according to an embodiment of the present invention; [Diagram 5] 5 is a diagram showing a state in which the components of FIG. 4 are combined. [Figure 6]4 is a view showing one of a plurality of venting portions formed in a burstable sheet included in a battery module according to the present invention; [Figure 7] This is an enlarged view of part D in FIG. 6, showing the state of the rupturable sheet before it ruptures. [Figure 8] 8 is a diagram showing the state in which the rupture sheet of FIG. 7 ruptures due to gas venting inside a battery cell. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to exemplary embodiments thereof, so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

[0030] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used to refer to the same or similar components throughout the specification.

[0031] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are enlarged to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0032] In addition, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the direction against gravity.

[0033] Additionally, throughout the specification, when a part "comprises" a certain element, this means that it can further include other elements, not excluding other elements, unless specifically stated to the contrary.

[0034] Also, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0035] The terms "first" and "second" used in this application may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another.

[0036] The battery module of the present invention will be described below with reference to FIGS.

[0037] Fig. 4 is an exploded perspective view of a battery module according to an embodiment of the present invention, and Fig. 5 is a view showing a state in which the components of Fig. 4 are combined.

[0038] 4 and 5, the battery module 100 of this embodiment includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, a module frame 200 that houses the battery cell stack 120, and a rupture sheet (500) formed between the battery cell stack 120 and the module frame 200.

[0039] First, the battery cell 110 is preferably a pouch-type battery cell and is formed in a rectangular sheet-type structure. For example, the battery cell 110 has a structure in which two electrode leads 111 and 112 face each other and protrude from one end and the other end of the cell body, respectively. That is, the battery cell 110 includes electrode leads 111 and 112 protruding in directions opposite each other. More specifically, the electrode leads 111 and 112 are connected to an electrode assembly (not shown) and protrude from the electrode assembly (not shown) to the outside of the battery cell 110.

[0040] A plurality of such battery cells 110 are configured, and the plurality of battery cells 110 are stacked so as to be electrically connected to each other to form a battery cell stack 120. In particular, as shown in Fig. 4, the plurality of battery cells 110 are stacked along a direction parallel to the y-axis. This allows the electrode leads 111, 112 to protrude in the x-axis direction and the -x-axis direction, respectively.

[0041] Meanwhile, the module frame 200 has an open top, front and rear, and includes a U-shaped frame 300 that covers the bottom and both sides of the battery cell stack 120, and an upper plate 400 that covers the top of the battery cell stack 120. In this case, the U-shaped frame 300 may include a bottom 300a that supports the bottom of the battery cell stack 120, and side portions that extend upward from both cut portions of the bottom 300a.

[0042] However, the module frame 200 is not limited to this and may be replaced with a frame of another shape, such as an L-shaped frame or a monoframe that surrounds the battery cell stack 120 except for the front and rear sides.

[0043] The module frame 200 can provide physical protection to the battery cell stack 120 received within the module frame 200 .

[0044] The top plate 400 may cover the open upper side of the module frame 200 .

[0045] The end plates 150 can cover the front and rear surfaces of the battery cell stack 120 that are exposed by the module frame 200. The end plates 150 can be joined to the front and rear end corners of the upper plate 400 and the front and rear end corners of the module frame 200 by welding.

[0046] The end plates 150 and the front and rear surfaces of the battery cell stack 120 In between,A bus bar frame 130 may be formed. The bus bar frame 130 may cover a portion of the battery cell stack 120 exposed from the module frame 200. In addition, a plurality of bus bars 160 attached to the bus bar frame 130 may be formed to protrude from the battery cells 110 and connected to the electrode leads 111, 112 attached to the bus bar frame 130. In this case, slots through which the electrode leads 111, 112 pass may be formed in the bus bar 160. Therefore, the electrode leads 111, 112 passing through the slots of the bus bar 160 may come into contact with the bus bar 160.

[0047] Furthermore, the battery module 100 further includes a thermally conductive resin layer 310 located between the underside of the battery cell stack 120 and the bottom of the module frame 200, i.e., the bottom 300a of the U-shaped frame 300, and the thermally conductive resin layer 310 can transfer heat generated in the battery cells 110 to the bottom of the battery module 100 and serve to fix the battery cell stack 120.

[0048] As described above, the burstable sheet 10 of the conventional battery module must be formed with a very thin thickness because the notch shape must be cut along the cutting line CC' in Fig. 3 when venting gas inside the battery cell. Furthermore, even if gas venting is not occurring inside the battery cell, the conventional burstable sheet 10 is likely to be damaged and the burstable portion 15 may be cut off due to external vibration and impact during use of a general battery module. In this case, the venting hole may be formed even when venting is not occurring inside the battery cell, exposing the internal structure of the battery module to the outside, thereby reducing stability.

[0049] Therefore, there is a need for a new structure that can improve the stability of the battery module by having the burstable sheet 10 burst only when the gas in the battery cell is vented, thereby venting the gas inside the battery cell, and not bursting the burstable sheet 10 during normal battery module use.

[0050] The burstable sheet 500 of the battery module 100 according to this embodiment will be described in more detail below.

[0051] Fig. 6 is an enlarged view of one of a plurality of vents formed in a burstable sheet included in a battery module of the present invention. Fig. 7 is an enlarged view of part D in Fig. 6, showing the state of the burstable sheet before it bursts. Fig. 8 is a view showing the state of the burstable sheet of Fig. 7 after it has burst.

[0052] 6 to 8, the rupture sheet 500 of the battery module 100 according to this embodiment is formed between the battery cell stack 120 and the module frame 200. More specifically, the rupture sheet 500 is formed between an upper portion of the battery cell stack 120 and an upper portion of the module frame 200. In addition, the rupture sheet 500 included in the battery module 100 according to this embodiment includes a shape memory alloy (SMA).

[0053] Holes 210 are formed in the module frame 200, and a plurality of holes 210 may be formed on the module frame 200. In this case, the holes 210 may be formed on the upper portion of the module frame 200, i.e., on the upper plate 400. That is, a plurality of holes 210 may be formed in the module frame 200, and the holes 210 may be formed to penetrate the upper portion of the module frame 200. Therefore, gas inside the battery module can be smoothly discharged to the outside through the holes 210 formed in the module frame 200.

[0054] Also, a venting portion 501 may be formed in a portion of the rupturable sheet 500 corresponding to the position of the hole 210. In this case, the venting portion 501 may be formed by forming a plurality of venting holes 550 in a portion of the rupturable sheet 500 corresponding to the shape of the hole 210 of the module frame 200, as described below. Thus, the venting portion 501 may be formed in a portion of the rupturable sheet 500 corresponding to the position of the edge of the hole 210. Thus, the venting portion 501 formed by a plurality of venting holes 550 is formed on the rupturable sheet 500, and a plurality of venting portions 501 are also formed on the rupturable sheet, so that a number of venting paths can be formed. Also, the venting paths allow gas to be rapidly discharged during gas generation and venting within the battery module.

[0055] At this time, the venting portion 501 of the rupture sheet 500 may include the shape memory alloy. That is, among the parts of the rupture sheet 500, the part of the rupture sheet 500 corresponding to the position of the hole 210, i.e., the venting portion 501, may include the shape memory alloy.

[0056] Meanwhile, the burst sheet 500 may include a plurality of burst layers 510, 520 including a first burst layer 510 and a second burst layer 520, and a burst induction member 530 formed between the plurality of burst layers 510, 520. The plurality of burst layers 510, 520 may include a greater number of burst layers, for example, a first burst layer 510 and a second burst layer 520, as will be described with reference to FIG. 7. In this case, the burst sheet 500 may include a venting portion 501, which is a portion of the burst sheet 500 corresponding to the hole 210 of the module frame 200, among the regions of the burst sheet 500, including the plurality of burst layers 510, 520 and the burst induction member 530. Therefore, the burst induction member 530 may be formed in a portion of the burst sheet 500 corresponding to the position of the hole 210 of the module frame 200.

[0057] The rupture inducing member 530 formed between the first rupture layer 510 and the second rupture layer 520 may be formed to contact the first rupture layer 510 and the second rupture layer 520, respectively. Therefore, the first rupture layer 510 and the second rupture layer 520 can also deform, rupture, and / or cut due to the change in shape of the rupture inducing member 530.

[0058] In addition, the first rupture layer 510 and the second rupture layer 520 can be formed of a plate-like sheet, but are not limited thereto.

[0059] At this time, the rupture inducing member 530 may include the shape memory alloy. More specifically, the rupture inducing member 530 may include the shape memory alloy or be made of the shape memory alloy, and expand as the shape memory alloy expands. That is, when heat of a certain temperature or more is applied to the rupture sheet 500, the rupture inducing member 530 expands to induce rupture and cutting of the rupture sheet 500. This is based on the characteristic that the shape memory alloy exists in a different shape at low temperatures, but remembers the shape at high temperatures, and returns to the high temperature shape when heat is applied.

[0060] 7 and 8, heat above a predetermined temperature may be generated during gas venting inside the battery cell 110 and the battery module 100. More specifically, heat having a temperature of at least 100° C. may also be generated during gas venting. Thus, the heat is transferred to the rupture inducing member 530 when the gas is vented.

[0061] The rupture inducing member 530 may include a member that expands when a temperature of at least 100 degrees is applied. Thus, the rupture inducing member 530 may expand during gas venting of the battery cell and the battery module. At this time, the rupture inducing member 530 that expands due to the heat transferred during the gas venting may be referred to as a first rupture inducing member 530a, and the rupture inducing member 530 that has not yet expanded may be referred to as a second rupture inducing member 530b.

[0062] Referring to FIG. 8, the first rupture inducing member 530a may expand due to the heat and cut a portion of the first rupture layer 510 and the second rupture layer 520. That is, the rupture inducing member 530 may expand and deform and cut the rupture layers 510 and 520. As a result, the deformed and cut first rupture layer 510 and second rupture layer 520 form a vent hole 550 on the rupture sheet 500, and the gas inside the battery module 100 may be discharged to the outside. At this time, referring to FIG. 6 and FIG. 8, the shape of the vent hole 550 is formed when the first rupture layer 510 and the second rupture layer 520 are cut and lifted up. Therefore, the vent hole 550 is formed along a black solid line or a curved shape as shown in FIG. 6, but the shape of the vent hole 550 is not limited thereto.

[0063] In particular, if the heat is also transferred to second rupture inducing member 530b, first rupture layer 510 and second rupture layer 520 may also be cut by second rupture inducing member 530b, and thus venting hole 550 may be formed to have a larger area than the size of venting hole 550 in the case where only first rupture inducing member 530a ruptures.

[0064] In addition, the rupture sheet 500, particularly the venting portion 501 on the rupture sheet 500, may include a plurality of rupture inducing members 530, and therefore the venting holes 550 may be formed in a plurality on the rupture sheet 500 and the venting portion 501.

[0065] Also, the rupture induction member 530 may be formed along the shape of the holes 210 of the module frame 200. That is, the plurality of venting holes 550 are formed along the shape along which the plurality of rupture induction members 530 are formed, and the shape of the venting portion 501 is formed along the shape along which the plurality of venting holes 550 are formed. In other words, the plurality of venting holes 550 are formed in a portion of the rupture sheet 500 corresponding to the positions of the holes 210, and the plurality of venting holes 550 formed in the portion of the rupture sheet 500 corresponding to the positions of the holes 210 may form the venting portion 501.

[0066] Therefore, in the normal operating state of the battery module 100, no venting holes 550 are formed in the rupture sheet 500. However, when gas inside the battery module 100 is vented, the rupture inducing member 530 forms venting holes 550 on the rupture sheet 500, thereby enabling the gas inside the battery module 100 to be effectively discharged to the outside.

[0067] Therefore, the burstable sheet 500 included in the battery module 100 of this embodiment forms the venting holes 550 and the venting portions 501 only when gas is vented in the battery cells 110 and the battery module 100, thereby improving the stability of the battery module and ensuring the performance of the battery module 100.

[0068] A battery pack according to still another embodiment of the present invention will now be described.

[0069] The battery pack according to the present embodiment includes the battery module described above. Furthermore, the battery pack of the present invention may be constructed by packing one or more battery modules according to the present embodiment together with a battery management system (BMS) for managing the temperature and voltage of the battery and a cooling device.

[0070] The battery pack can be applied to various devices, including vehicles such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and can be applied to various devices that can use a battery module, which also fall within the scope of the present invention.

[0071] Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above. Of course, the present invention can be modified in various ways by a person having ordinary skill in the art without departing from the gist of the present invention as claimed in the claims, and such modified embodiments should not be understood separately from the technical ideas and perspectives of the present invention. [Explanation of symbols]

[0072] 100: Battery module 110: Battery cell 120: Battery cell stack 130: Busbar frame 150: End plate 160: Busbar 200:Module frame 300: U-shaped frame 400: Top plate 500: Burstable sheet 501: Venting Department 510: 1st rupture layer 520:Second rupture layer 530: Explosion-inducing material 550: Venting Hole

Claims

1. a battery cell stack in which a plurality of battery cells are stacked; a module frame that houses the battery cell stack; and a rupture sheet formed between the battery cell stack and the module frame, The rupture sheet includes a shape memory alloy (SMA), The module frame has a plurality of holes formed therein, a portion of the rupture sheet corresponding to the location of the hole includes the shape memory alloy; The burstable sheet is A plurality of burst layers; and The bursting layer includes a bursting inducer formed between the bursting layers, The rupture induction member is formed of the shape memory alloy.

2. The battery module of claim 1 , wherein the rupture inducing member is formed at a portion of the rupture sheet corresponding to a position of a hole of the module frame.

3. The rupture-inducing member expands during gas venting of the battery module, The battery module of claim 1 , wherein the rupture inducing member expands to deform the rupture layer, thereby forming a vent hole on the rupture sheet.

4. The rupture induction member is 4. The battery module of claim 3, wherein the shape memory alloy expands as it expands.

5. The battery module of claim 3 , wherein the vent hole is formed in a plurality of holes.

6. The plurality of venting holes are formed in the rupture sheet at portions corresponding to the positions of the holes; The battery module of claim 5 , wherein the plurality of venting holes formed in the portion of the burst sheet corresponding to the positions of the holes form a venting portion.

7. The rupture induction member is The battery module of claim 1 , wherein the bursting inducer comprises a member that expands when exposed to a temperature of 100° C. or higher.

8. The battery module according to claim 1 , wherein the burst sheet is formed between an upper portion of the battery cell stack and the module frame.

9. A battery pack comprising the battery module according to any one of claims 1 to 8.

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