ES3064683T3 - Battery module, and battery pack and energy storage system including same - Google Patents

Abstract

A battery module of the present invention comprises a housing section in which an electrode assembly is housed, and a cell stack comprising several battery cells stacked vertically and oriented toward the housing section. The battery cells include first and second edge sections along the longitudinal direction, and third and fourth edge sections along the width direction, surrounding the housing section. In this section, the battery cells include a sealing section in the first edge section, and the second edge section includes either a sealing section or an unsealed section. The first and second edge sections are alternately positioned along the vertical direction on both sides of the cell stack.

Description

[0001] DESCRIPTION

[0002] Battery module, battery pack and energy storage system including the same. Technical Sector

[0003] This disclosure relates to a battery module, a battery pack, and an energy storage system (ESS) including the same, and more specifically to an ignition-preventing battery module, a battery pack, and an ESS including the same. This application claims priority over Korean patent application No. 10-2022-0130431 filed on October 12, 2022, and Korean patent application No. 10-2023-0060685 filed on May 10, 2023.

[0004] Background of the invention

[0005] As technological development and the demand for various mobile devices, electric vehicles, energy storage systems (ESS), and similar products increase significantly, interest in and demand for secondary batteries as a power source are rapidly growing. Nickel-cadmium or nickel-hydrogen batteries have been widely used as conventional secondary batteries, but recently, lithium-ion secondary batteries, with advantages such as free charging/discharging, a very low self-discharge rate, and high energy density due to a minimal memory effect compared to nickel-based secondary batteries, are being used extensively.

[0006] Lithium secondary batteries primarily use a lithium-based oxide and a carbon material as the positive and negative electrode active materials, respectively. Lithium secondary batteries include an electrode assembly in which a positive electrode plate and a negative electrode plate are coated with the positive and negative electrode active materials, respectively. These are arranged with a separator between them and an outer material that seals and houses the electrode assembly along with an electrolyte—that is, a battery casing.

[0007] In general, lithium secondary batteries can be classified into can-type secondary batteries, in which the electrode assemblies are embedded in a metal can, and bag-type secondary batteries, in which the electrode assemblies are embedded in a bag of laminated aluminum sheets, depending on the shape of the outer material.

[0008] Recently, battery packs have been widely used for power generation or energy storage in medium/large devices, such as electric vehicles and energy storage systems (ESS). A battery pack includes one or more battery modules and a control unit that manages the charging/discharging of the battery pack, all housed within a pack casing. Here, the battery module is configured to include a plurality of battery cells within a module housing. US2012/196170 and KR 20220036171 each disclose examples of battery modules. Specifically, in the case of a battery pack, a plurality of battery cells (secondary batteries) are housed within a module housing to form each battery module, and one or more of these battery modules are housed within the pack casing to form a battery pack. In particular, pouch batteries offer advantages in several aspects, such as their light weight and reduced dead space when stacked, but they are problematic in that they are vulnerable to external impacts and somewhat inferior in assembly. Therefore, it is common for a battery pack to be manufactured by first modularizing a plurality of battery cells and then separating them within a pack casing.

[0009] Although pouch batteries have excellent electrical characteristics, a decomposition reaction of active materials and electrolytes, which are battery components, is activated under abnormal operating conditions, such as overcharging, over-discharging, exposure to high temperatures, and electrical short circuits. This generates heat and gas, and as a result, a problem known as swelling may occur, causing the secondary battery to expand. The swelling phenomenon accelerates this decomposition reaction, which can lead to the explosion and ignition of the battery cell due to thermal runaway.

[0010] In other words, a flare, which is a flame emanating from a weakly sealed area, a spark, which is a very hot particle emitted by the disintercalation of the internal electrode and the melting of the aluminum current collector, and high-temperature venting gas are generated in the event of a thermal runaway battery cell. These elements do not remain confined to that location but also spread to surrounding modules, including battery cells located nearby, making it highly likely that they will cause a serious accident.

[0011] In the current field of battery ignition suppression, spark and flame blocking technology using physical baffles has been dominant in its attempts to prevent directional venting of battery cells and flame directionality. Furthermore, simply changing the blocking method without adjusting the heat source arrangement to resolve battery ignition has reached its limit in addressing thermal propagation as energy density increases.

[0012] Explanation of the invention

[0013] Technical Problem

[0014] The present disclosure is designed to solve problems in the related art and, therefore, the present disclosure is directed to provide a battery module capable of preventing battery fires, especially explosive fires accompanied by auto-ignition.

[0015] This disclosure is also intended to provide a battery pack and ESS that have enhanced safety by including such a battery module that prevents ignition.

[0016] Technical solution

[0017] A battery module for solving the problem described above is as defined in claim 1, comprising a cell stack formed by stacking a plurality of battery cells comprising a receiving portion housing an electrode assembly, a first edge portion and a second edge portion along the longitudinal direction around the receiving portion, and a third edge portion and a fourth edge portion along the width direction, vertically with the receiving portions facing each other, the battery cell comprising a resealing portion on the first edge portion, and comprising a sealing portion or an unsealed portion on the second edge portion, and the first edge portion and the second edge portion being alternately positioned along the vertical direction on both sides of the cell stack. The battery module according to the invention further includes a module housing that houses the cell stack, the module housing includes a pair of side plates located on both sides of the cell stack, and the side plate and cell stack are separated to form a portion of space.

[0018] A battery module may further include a polycarbonate (PC) sheet and a mica sheet between the module housing and the side of the cell stack.

[0019] A first edge portion of approximately half of the plurality of battery cells may be oriented towards one of the side plates, and a first edge portion of the remaining battery cells may be oriented towards the other of the side plates.

[0020] A battery module according to another embodiment of the present disclosure may further include a module housing that houses the cell stack, the module housing may include a pair of side plates located on both sides of the cell stack and a top plate covering the upper portion of the cell stack, and the side plates may be thicker than the top plate.

[0021] A battery module according to yet another embodiment of the present disclosure may further include a module housing that houses the cell stack, the module housing may include a pair of side plates located on both sides of the cell stack and a top plate covering the upper portion of the cell stack, and the side plate may be made of a material having a specific heat higher than that of the top plate.

[0022] A battery module according to yet another embodiment of the present disclosure may further include a module housing that houses the cell stack, the module housing may include a pair of side plates located on both sides of the cell stack, and heat dissipation fins may be formed on the outer side of the side plate.

[0023] A battery module in accordance with yet another embodiment of the present disclosure may further include a thermal separator between the module housing and the cell stack side.

[0024] A battery module of this disclosure may further include a damping pad located on at least one of the upper and lower portions of the cell stack.

[0025] A battery module of this disclosure may further include an insulating plate located on at least one of the upper and lower portions of the cell stack.

[0026] The module housing may further include a base plate supporting the cell stack and a top plate covering the upper portion of the cell stack, and the base plate may have a U-shaped frame structure capable of wrapping and securing the lower end of the side plate from the outside.

[0027] Here, the top plate and side plates can be connected together to form a U-shaped frame structure.

[0028] A battery module of this disclosure may further include a module housing that houses the cell stack, the module housing may include a pair of side plates located on either side of the cell stack and a top plate covering the upper portion of the cell stack, the module housing may have a module opening formed in the longitudinal direction, and the module housing may further include a busbar frame assembly covering the module opening.

[0029] In the present invention, the pair of side plates includes a pair of spark direction change portions formed by bending one end in the longitudinal direction towards the cell stack.

[0030] Here, the battery module may further include a clamping frame that connects the pair of spark direction change portions and has an empty central area.

[0031] In addition, the battery cell may include electrode conductors in the third edge portion and in the fourth edge portion, the module housing may further include a top plate covering the top portion of the cell stack, the module housing may have an opening formed in the longitudinal direction, the module housing may further include a bus bar frame assembly covering the module opening, and the bus bar frame assembly may be in close contact with the spark direction-changing portion and the clamping frame.

[0032] To solve the other above problems, the present invention provides a battery pack that includes said battery module.

[0033] Furthermore, the present invention also provides an ESS that includes said battery module or battery pack.

[0034] Advantageous effects

[0035] According to one aspect of this disclosure, when battery cells are stacked to form a battery module, battery pack, and the like, the resealed portions are stacked in a zigzag pattern so that they are not tilted in a single direction. The zigzag stacking allows sealing portions to be placed on both sides of the cell stack, i.e., in both directions. The resealed portion, which is relatively weak in sealing, can be opened to allow bidirectional venting or thermal energy dissipation. By doing so, a large number of high-temperature, high-pressure sparks and flames emitted by thermal leakage from the battery cell can be dispersed to reduce pressure and maintain the temperature of the outer wall of the module or battery pack below 500°C, thereby blocking auto-ignition and explosion caused by contact with the hydrogen and oxygen in the surrounding vent gas.

[0036] According to another aspect of this disclosure, by improving the module housing, the temperature of the module housing's side plate can be managed to be below 500 °C even if the vent gas is discharged through the resealed portion. Therefore, it is possible to effectively prevent auto-ignition caused by contact with the hydrogen and oxygen in the surrounding vent gas.

[0037] According to another aspect of this disclosure, by improving the module housing, the movement of flares and sparks generated during thermal runaway of the battery cells can be blocked, thus preventing fires from occurring or flames from spreading to nearby battery modules.

[0038] Brief description of the drawings

[0039] The accompanying drawings illustrate a preferred embodiment of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure and, therefore, the present disclosure is not to be construed as being limited to the drawing.

[0040] Figure 1 is a perspective view of a battery cell included in a battery module according to an embodiment of the present disclosure.

[0041] Figure 2 is a view to describe a method of manufacturing a battery cell included in a battery module according to an embodiment of the present disclosure.

[0042] Figure 3 is a cross-sectional view of a battery module according to an embodiment of the present disclosure.

[0043] Figure 4 is an exploded perspective view of a cell stack included in the battery module of Figure 3.

[0044] Figure 5 is an exploded perspective view showing another example of a cell stack.

[0045] Figure 6 is an exploded perspective view of a cell stack according to a comparative example. Figures 7 to 10 are views according to a modified example of the battery module shown in Figure 3.

[0046] Figure 11 is a perspective view of a battery module according to another embodiment of the present disclosure.

[0047] Figure 12 is an exploded perspective view of the battery module shown in Figure 11.

[0048] Figure 13 is an exploded perspective view of a cell stack included in the battery module of Figure 11.

[0049] Figure 14 is an exploded perspective view of some components located on the back of the battery module in Figure 11.

[0050] Figure 15 is an exploded perspective view of some components located on the front of the battery module in Figure 11.

[0051] Figure 16 is a partially cut perspective view of the battery module in Figure 11.

[0052] Figure 17 is a cross-sectional view parallel to the longitudinal direction of the battery module in Figure 11.

[0053] Figure 18 is a schematic view of a battery pack including a battery module according to an embodiment of the present disclosure.

[0054] Figure 19 is a schematic view of an ESS including a battery module according to an embodiment of the present disclosure.

[0055] Preferred embodiment of the invention

[0056] Hereafter, preferred embodiments of the present disclosure will be described in detail, with reference to the accompanying drawings. Before proceeding with the description, it should be understood that the terms used in the specification and in the appended claims should not be interpreted as limited to general and dictionary meanings, but rather should be interpreted in light of the meanings and concepts corresponding to the technical aspects of the present disclosure, based on the principle that the inventor may define terms appropriately for better explanation. Therefore, the description proposed herein is only a preferred example for illustrative purposes only and is not intended to limit the scope of the disclosure. It should be understood that other equivalences and modifications may be made without departing from the scope of the disclosure. The invention is defined by the appended claims.

[0057] Figure 1 is a perspective view of a battery cell included in a battery module according to an embodiment of the present disclosure.

[0058] Referring to Figure 1, battery cell 10 includes an outer bag material 20 and an electrode assembly (not shown), and a pair of electrode conductors 30 protrude out of the outer bag material 20. And battery cell 10 includes a sealing portion 40 and a resealing portion 50. Thus, battery cell 10 is a bag-type battery cell.

[0059] Herein, the electrode assembly may include, but is not limited to, a jelly-roll type assembly in which a separator is placed between a long, sheet-like positive electrode and a negative electrode and then rolled up, a stack type assembly in which a rectangular positive electrode and a negative electrode are stacked with a separator between them, a fold-stack type assembly in which the unit cells are rolled up by means of a long separator sheet, or a lamination-type assembly in which the battery cells are stacked with a separator between them and joined together.

[0060] Furthermore, it is evident that the electrolyte can be replaced by a solid electrolyte or a nearly solid electrolyte in the form of a gel intermediate between liquid and solid, by adding additives to the solid electrolyte, in addition to the liquid electrolyte commonly used.

[0061] The electrode assembly described above is housed within the outer material of bag 20, which typically has a laminated sheet structure consisting of an inner layer, a metallic layer, and an outer layer. Since the inner layer is in direct contact with the electrode assembly, it should possess insulating properties and electrolyte resistance, as well as sealing properties to the outer layer. In other words, the sealing portion where the inner layers are thermally bonded should have excellent thermal bonding strength. The material for this inner layer can be selected from, but is not limited to, polyolefin-based resins such as polypropylene, polyethylene, acrylic acid, polyethylene, and polybutylene, as well as polyurethane and polyimide resins, which have excellent chemical resistance and good sealing properties. Among these, polypropylene, with its excellent mechanical properties such as tensile strength, stiffness, surface hardness, impact resistance, and chemical resistance, is preferred.

[0062] The metallic layer in contact with the inner layer corresponds to a barrier layer that prevents moisture or various gases from penetrating the battery from the outside, and as a preferred material for this metallic layer, a thin film of aluminum that is lightweight and has excellent conformability can be used.

[0063] The other side of the metallic layer is provided with an outer layer, which can be made of a heat-resistant polymer having excellent tensile strength, moisture permeability prevention, and air permeability prevention to ensure heat and chemical resistance, while protecting the electrode assembly. Nylon or polyethylene terephthalate, for example, can be used, but are not limited to these. Meanwhile, the pair of electrode conductors 30 consists of a positive electrode conductor and a negative electrode conductor. These can be exposed to the outside of the outer bag material 20 after the positive and negative electrode tabs of the electrode assembly are electrically connected, respectively, or they can be connected directly to the electrode assembly without the tabs. The battery cell 10 includes a receiving portion R in which the electrode assembly is housed, and edge portions E1 to E4 surrounding the receiving portion R. In particular, the battery cell 10 has a first edge portion E1 and a second edge portion E2 along the longitudinal direction (X-axis direction in the drawing), and a third edge portion E3 and a fourth edge portion E4 along the width direction (Y-axis direction in the drawing). Thus, the battery cell 10 can have four edge portions E1 to E4. In this embodiment, the electrode conductors 30 are included in the third edge portion E3 and the fourth edge portion E4. A space between the two ends of the electrode conductors 30 protruding from the outer bag material 20 can be defined as a longitudinal direction of the battery cell 10. As such, the electrode conductors 30 can be provided at both the front and rear ends in the longitudinal direction of the battery cell 10, i.e., at the front and rear ends of the battery cell 10.

[0064] The first edge portion E1 includes a reseal portion 50. The third edge portion E3 and the fourth edge portion E4 include a sealing portion 40. In the case of a four-side sealing method, the second edge portion E2 also includes the sealing portion 40. In the case of a three-side sealing method, only the second edge portion E2 includes an unsealed portion. Here, the unsealed portion refers to a portion where the outer bag material is folded over. The illustrated example shows an example of a four-side sealing method. Accordingly, the first edge portion E1 includes the resealing portion 50, and the second edge portion E2, the third edge portion E3, and the fourth edge portion E4 include the sealing portion 40. The sealing portion 40 is a portion where the outer bag material 20 is joined to seal the perimeter of the receiving portion R. The resealing portion 50 refers to a sealing portion resulting from a resealing operation performed after the degassing process of the battery cell 10.

[0065] In the configuration of a battery module or battery pack using battery cells, the space occupied by the battery cell within the device can be reduced by minimizing the size of the battery module to increase space utilization. Alternatively, the size of the electrode assembly can be increased using the resulting surplus by minimizing the area occupied by the sealing portion for a given battery module size to increase the secondary battery capacity. Regarding the latter, dimensions are primarily managed by folding the sealing portion located on the side of the battery cell to form a foldable portion. In the illustrated example, the resealing portion 50 of the first edge portion E1 and the sealing portion 40 of the second edge portion E2 are folded. However, if simply folded, it may unfold due to the swelling phenomenon of the folded cell itself. Therefore, it can be taped to prevent this. Part number 60 is a taping member.

[0066] A plurality of the battery cells 10 described above can be stacked along the Z-axis direction to form a battery module. Since the battery cells 10 are flat along the XY plane, it is highly advantageous to stack them densely along the Z-axis direction.

[0067] Figure 2 is a view to describe a method of manufacturing a battery cell included in a battery module according to an embodiment of the present disclosure.

[0068] Battery cell 10 is manufactured by a secondary battery assembly process and a secondary battery activation process.

[0069] The outer bag material 20 may include a lower outer material in which the electrode assembly is housed and an upper outer material that seals the upper portion of the lower outer material. In the case of a four-sided sealing method, the lower outer material and the upper outer material are two separate sheets. In the case of a three-sided sealing method, a sheet of outer bag material may be folded to form a lower outer material and an upper outer material.

[0070] The secondary battery is assembled by housing the electrode assembly in the receiving portion R of the lower outer material, then pressing the rim around the receiving portion R of the lower outer material and the corresponding rim of the upper outer material, thermally welding a portion of the pressed portions together, adding an electrolyte, and vacuum-sealing the remaining portion. The receiving portion R may also be formed from the upper outer material. By the four-sided sealing method, the four rim portions E1 to E4 are formed once as sealing portions 40.

[0071] In the activation process, the secondary battery is mounted on a predetermined jig for smooth current flow, and a process such as charging/discharging or similar is performed as a necessary condition for activation. Due to the nature of the secondary battery, this activation process must be preceded by the activation of the positive electrode active material and the creation of a stable solid electrolyte interface (SEI) at the negative electrode in the first cycle. During the activation process, a large amount of gas is generated inside the secondary battery. The generated gas is then vented through an open or incised outlet, and the gas discharge section is heat-welded to seal it. The process of discharging the gas inside the secondary battery and heat-welding the discharge passage, as described above, is commonly known as the degassing process. And the part that has been heat-sealed and resealed is the reseal portion 50 itself. In this embodiment, the reseal portion 50 is included in the first edge portion E1. The excess outer bag material 20 on the outside of the reseal portion 50 is cut off and removed.

[0073] Since the reseal portion 50 of the first edge portion E1 is formed by resealing after a degassing process, the inventors have found that it has a weaker sealing strength than the sealing portion 40 of the second edge portion E2 on the opposite side and therefore tends to tear first in the event of thermal runaway. Furthermore, it has been found that when a plurality of battery cells 10 are housed in a module housing, if this reseal portion 50 is concentrated on one side, the module housing may melt if it is made of aluminum. Additionally, it has been found that when a plurality of battery cells 10 are housed, if this reseal portion 50 is concentrated on one side, the module housing may not melt, but the temperature of its outer wall becomes high, up to 800 °C or more if it is made of steel. This time, if the temperature exceeds 505 °C, there is a high probability that the hydrogen in the vent gas flowing around it will mix with the oxygen and explode. This is auto-ignition. The inventors devised this disclosure based on the fact that auto-ignition of a battery module can be prevented by controlling the temperature of the module housing by adjusting the arrangement of the reseal portion 50.

[0075] Figure 3 is a cross-sectional view of a battery module according to an embodiment of the present disclosure. A cross-section cut along the width direction perpendicular to the longitudinal direction of the battery cell and the battery module is shown. Figure 4 is an exploded perspective view of a cell stack included in the battery module of Figure 3. Figure 5 is an exploded perspective view showing another example of a cell stack.

[0077] Referring to Figures 3 to 5, the battery module 100 includes a cell stack 110 comprising a plurality of battery cells 10, as described above, and a module housing 120 housing the cell stack 110. In particular, it has a configuration wherein the resealable portions 50 of the battery cells 10 are distributed and stacked within the cell stack 110.

[0079] A plurality of battery cells 10 are stacked in the vertical direction (Z-axis direction in the drawing) with the receiving portions R oriented toward each other to form the cell stack 110. The up-and-down direction may also be referred to as the vertical direction or the Z-axis direction. In the present disclosure, the resealing portions 50 of all the battery cells 10 are stacked so that they are not oriented in a single direction. For example, the resealing portions 50 are arranged in both directions in the width direction within the cell stack 110. For example, along the Z-axis, the resealing portions 50 are stacked in a zigzag pattern, with one resealing portion 50 positioned on the left and the other resealing portion 50 on the right. Therefore, the first edge portion E1, which includes the reseal portion 50, and the second edge portion E2, which does not include the reseal portion 50, are alternately positioned along the vertical direction on either side of the cell stack 110. The second edge portion E2 includes either a seal portion 40 or an unsealed portion, as mentioned above.

[0081] In this case, as shown in Figure 4, a first border portion E1 including the resealing portion 50 and a second border portion E2 not including the resealing portion 50 can be alternately placed along the vertical direction on either side of the cell stack 110, or as shown in Figure 5, several first border portions E1 including the resealing portion 50 and several second border portions E2 not including the resealing portion 50 can also be alternately placed. For example, as shown in Figure 5, two or more can be alternately placed.

[0083] In any case, preferably, the plurality of battery cells 10 are stacked alternately, distributing approximately half of the resealing portions 50 (positioned on both sides in the width direction) toward the left wall and toward the right wall, respectively, within the module housing 120. By doing this, the pressure and temperature concentrated on both walls of the module housing 120 within the stack of cells 110 can be significantly reduced. For example, if the number of battery cells 10 is 2n, n battery cells 10 have their resealing portions 50 positioned toward the left wall, and the remaining n battery cells 10 have their resealing portions 50 positioned toward the right wall. If the number of battery cells 10 is 2n+1, n or n+1 battery cells 10 have their reseal portions 50 positioned towards the left wall, and the remaining n+1 or n battery cells 10 have their reseal portions 50 positioned towards the right wall.

[0084] In this way, even if the first edge portion E1 and the second edge portion E2 are stacked alternately and repeatedly along the vertical direction, vertical alignments are made between the third edge portions E3, between the fourth edge portions E4, and between the third edge portion E3 and the fourth edge portion E4 on the front and rear sides, and thus the electrode conductors 30 can be stacked while aligning in the vertical direction in a row on the front and rear sides of the cell stack 110. Obviously, it will be appreciated that the polarities of the electrode conductors 30 placed at the front can all be the same, or the opposite polarities can be placed along the vertical direction. Furthermore, it will be appreciated that some battery cells 10 can be stacked upside down, taking into account the polarity of the electrode conductor 30 and the arrangement of the resealing portion 50.

[0085] The module housing 120 shown in Figure 3 has an internal space to house the battery cells 10 and serves to provide mechanical support to the housed battery cells 10 and to protect them from external impacts. Looking at Figure 3 in more detail, the module housing 120 includes a pair of side plates 130 located on either side of the cell stack 110. The module housing 120 may also include a top plate 140 that covers the upper portion of the cell stack 110 and a base plate 150 that supports the cell stack 110.

[0086] The side plate 130 and the cell stack 110 can be separated to form a space portion S. This space portion S can be configured to trap flares and sparks ejected during inflation. For example, a pair of side plates 130 can be separated and oriented at a distance slightly greater than the width W of the cell stack 110 to form the space portion S.

[0087] Furthermore, the battery module 100 may also include a PC sheet 160 and a mica sheet 170. The PC sheet 160 and the mica sheet 170 may be included between the module housing 120 and the side of the cell stack 110. In particular, in this embodiment, they are included between the side plate 130 and the side of the cell stack 110. The PC sheet 160 and the mica sheet 170 may be located on either side of the cell stack 110. The mica sheet 170 has excellent heat resistance to withstand high-temperature ventilation gases and sparks. The PC sheet 160 and the mica sheet 170 are ductile or easily reshaped, and when flames occur in any of the battery cells 10, they can block the spread of flames or heat from the flames to other battery cells 10 or to the side plate 130.

[0088] The first edge portion E1 of approximately half of the plurality of battery cells 10 included in the cell stack 110 is oriented towards the left side plate 130a, which is one of the side plates 130, and the first edge portion E1 of the remaining battery cells 10 is oriented towards the right side plate 130b, which is the other of the side plates 130. By doing this, the pressure and temperature concentrated on both side plates 130a, 130b when vented through the reseal portion 50 within the cell stack 110 can be distributed evenly to both sides, and the temperature of the side plate oriented towards the reseal portion 50 can be significantly reduced compared to the case where it is tilted to one side.

[0089] As a comparative example, Figure 6 illustrates a stack of 110' cells in which the reseal portion 50 is arranged in a single direction, for example, to the left. In this stack of 110' cells, the eight reseal portions 50 are configured as battery modules while facing one wall of the module housing. Thus, if the reseal portions 50 are tilted to one side, they may be exposed to high temperatures and high pressures for a short period of time, which can lead to a gas explosion. This is because if the vulnerable reseal portions 50 are clustered on one side, the temperature rise is at its maximum, resulting in auto-ignition when they come into contact with flammable and explosive vent gas and explode.

[0090] Since the resealed portion 50 is formed by resealing after a degassing process, it is more vulnerable than the sealed portion 40 or the unsealed portion on the opposite side and may therefore tear first in the event of thermal runaway. If these resealed portions 50 are concentrated on one side, as in the comparative example, the module housing may melt if it is made of aluminum. Even if the module housing does not melt, the temperature of its outer wall becomes very high, reaching 800°C or more if it is made of steel. If the temperature exceeds 505°C, auto-ignition occurs, in which hydrogen from the surrounding vent gas can mix with oxygen and explode. For this reason, the battery module containing the cell stack 110' in the comparative example is inevitably vulnerable to fire.

[0091] On the other hand, in the cell stack 110 included in the battery module 100 of this disclosure, the arrangement of the reseal portion 50 is adjusted to prevent auto-ignition. In this disclosure, when stacking the battery cells 10 to form a battery module 100, a battery pack including such battery module 100 and the like, i.e., when constructing the cell stack 110, the reseal portions 50 are stacked in a zigzag pattern to prevent the reseal portions 50 from tilting in any direction. The zigzag stacking allows the reseal portions 50 to be positioned side by side in both directions. The resealed portion 50, located in both directions, opens before the sealed portion 40 or the unsealed portion. Since the resealed portion 50 is arranged in both directions, bidirectional venting is possible. Furthermore, thermal energy can be dispersed in both directions. By doing so, a large number of high-temperature, high-pressure sparks and flames emitted by the thermal leakage of battery cell 10 can be dispersed to reduce pressure and maintain the temperature of the outer wall of module 120 housing below 500 °C. Therefore, it is possible to prevent auto-ignition and explosion caused by the contact of the surrounding venting gas with hydrogen and oxygen.

[0092] Meanwhile, although Figure 3 shows that the base plate 150, top plate 140, and pair of side plates 130 are all manufactured separately and then combined, it is also possible to manufacture the base plate 150 and the pair of side plates 130 or the top plate 140 and the pair of side plates 130 as a single piece and then assemble them. The base plate 150, top plate 140, and pair of side plates 130 can all be made of the same material. Furthermore, Figure 3 schematically shows the shapes of the base plate 150, top plate 140, and pair of side plates 130. The effect of the distributed arrangement of the resealing portion 50 can be maximized in combination with various embodiments of the module housing 120, which will be described below.

[0094] Figure 7 is a modified example of the battery module 100 shown in Figure 3 and includes an improved module housing 120. In this embodiment, the thickness d2 of the side plate 130 is thicker than the thickness d1 of the top plate 140 (d1 < d2).

[0096] Due to the structure of the cell stack 110, the vent gas discharged from the resealing portion 50 first strikes the side plate 130. The change in the amount of heat in the side plate 130 due to the vent gas is Q_in (the amount of heat entering the side plate 130) - Q_out (the amount of heat leaving the side plate 130), which can be said to be equal to C_p × M × ΔT. Here, C_p is the specific heat of the side plate 130, M is the mass of the side plate 130, and ΔT is the change in temperature. When Q_in - Q_out is constant, ΔT can be made smaller by increasing M. In other words, if the thickness d₂ of the side plate 130 is increased, M can be increased to reduce the temperature change. However, indiscriminately increasing the thickness d2 of the side plate 130 is undesirable because it leads to increased material costs and an increased weight of the entire battery module 100. The thickness d2 of the side plate 130 is increased within a reasonable budget. For example, if the thickness of the module housing 120 currently in use is 1.6 mm, the thickness d2 of the side plate 130 is adjusted to be thicker, such as 1.8 mm. Furthermore, to keep overall material cost and weight down, the top plate 140 can be configured to have a reduced thickness d1 as the thickness d2 of the side plate 130 increases. As such, in the battery module 100 of Figure 7, the thickness d2 of the side plate 130 is greater than the thickness d1 of the top plate 140. For example, the thickness d1 of the top plate 140 is 1.6 mm, the thickness d2 of the side plate 130 is 1.8 mm, and so on.

[0098] The thickness d1 of the top plate 140 and the thickness d2 of the side plate 130 can be determined considering various conditions, such as material cost, weight, fire prevention, and durability. They can also be determined considering factors such as thermal stress or thermal strain caused by the thickness difference if the top plate 140 and the side plate 130 are made of the same material. For example, the thickness d2 of the side plate 130 can be determined to be between 5% and 50% thicker than the thickness d1 of the top plate 140.

[0100] By increasing the thickness d2 of side plate 130 in this way to increase the M of side plate 130, the temperature of side plate 130 can be managed to be 500 °C or less, even if the vent gas is discharged through the reseal portion 50. Therefore, it is possible to effectively prevent auto-ignition caused by contact with hydrogen and oxygen from the surrounding vent gas.

[0102] Figure 8 is another modified example of the battery module 100 shown in Figure 3 and also includes an improved module housing 120. In this embodiment, the side plate 130 is made of a material whose specific heat is higher than that of the top plate 140. That is, the material of the top plate 140 and the material of the side plate 130 are different, and the side plate 130 has a higher specific heat.

[0104] As mentioned previously, due to the structure of the cell stack 110, the vent gas discharged from the resealing portion 50 first strikes the side plate 130. In the change in the amount of heat on the side plate 130 due to the vent gas, Q_in - Q_out = C_p×M×ΔT, when Q_in - Q_out is constant, ΔT can be made smaller by increasing C_p. In other words, the temperature change can be reduced by increasing the specific heat of the side plate 130. However, indiscriminately increasing the specific heat of the side plate 130 is undesirable due to the increased material costs and the difficulty of selecting a suitable material. The specific heat of the side plate 130 is increased within a reasonable budget. For example, if the module housing 120 currently in use is made of a material with a specific heat of 0.461 (J/gC), the specific heat of side plate 130 is set at 0.48 to 0.5 (J/gC), which is higher than the former.

[0105] Furthermore, if the cost of the alloy to increase the specific heat is high, the specific heat of the top plate 140 can be reduced as much as the specific heat of the side plate 130 is increased to maintain the overall material cost. As such, in the battery module 100 of Figure 8, the specific heat of the side plate 130 is configured to be higher than the specific heat of the top plate 140. For example, the specific heat of the side plate 130 can be increased by configuring the top plate 140 to be galvanized steel and the side plate 130 to also include metals such as aluminum, titanium, magnesium, and silicon, which have a higher specific heat than zinc or iron, in the form of an alloy or metal deposition.

[0107] By thus increasing the specific heat of side plate 130, Qin - Qout, which is a change in the amount of heat of side plate 130, it can be managed to reduce △T, thereby ensuring that the temperature of side plate 130 is 500 °C or lower, even if vent gas is discharged through the resealable portion 50. Therefore, it is possible to effectively prevent auto-ignition caused by contact with hydrogen and oxygen in the surrounding vent gas.

[0108] Figure 9 is yet another modified example of the battery module 100 shown in Figure 3 and includes an improved module housing 120. In this embodiment, the heat dissipation fins 135 are formed on the outer side of the side plate 130.

[0109] It has been pointed out several times that, due to the structure of the cell stack 110, the vent gas discharged from the resealable portion 50 first strikes the side plate 130. In this embodiment, by including the heat dissipation fins 135 on the side plate 130, the heat can be dissipated to the outside without accumulating on the side plate 130. The heat dissipation fin 135 is configured to maximize the surface area for effective heat dissipation. By doing this, even if the vent gas is discharged through the resealable portion 50, the temperature of the side plate 130 can be managed to be 500 °C or lower, thus preventing auto-ignition. Figure 10 is yet another modified example of the battery module 100 shown in Figure 3, and in this embodiment, a thermal spreader 180 is also included between the side plate 130 and the side of the cell stack 110.

[0110] Here, the thermal spreader 180 refers to an object that absorbs and dissipates heat from another object through direct thermal contact. The thermal spreader 180 may have a material and structure specialized for heat conduction and radiation, so that it can take heat from the heat-generating battery cell 10 and release it to the surroundings. For example, the thermal spreader 180 may be a member that is attached to the inside of the side plate 130, diffusing and releasing the heat generated in the battery cell 10. The thermal spreader 180 may include silicon, acrylic, or graphite.

[0111] In addition to the thermal spreader 180, the battery module 100 may also include a thermal interface material (TIM) layer to enhance heat transfer performance between the various components. The TIM layer is intended to reduce the thermal contact resistance between the members. This TIM layer may consist of various thermally conductive materials, such as metal, polymer, or ceramic, and may be composed of a gel-like or phase-change material. For example, the TIM layer may be a thermally conductive resin called thermal resin.

[0112] By including the heat spreader 180, heat can be dissipated to the outside instead of accumulating on the side plate 130. According to this embodiment of the present disclosure, the heat dissipation performance of the battery cell 10 can be further improved. By doing so, even if the vent gas is discharged through the resealable portion 50, the temperature of the side plate 130 can be managed to be 500°C or lower, thus preventing auto-ignition.

[0113] Meanwhile, the effect of the distributed arrangement of the reseal portion 50 according to the present disclosure can be further maximized in a battery module having a spark cavity structure that will be described below.

[0114] Figure 11 is a perspective view of a battery module according to another embodiment of the present disclosure.

[0115] Referring to Figure 11, the battery module 200, according to another embodiment of the present disclosure, has a substantially rectangular parallelepiped outer shape and includes a module housing 220 made of a metallic material. These battery modules 200 are formed into a substantially rectangular parallelepiped and can be arranged in an orderly fashion without wasting space in the pack housing.

[0116] Figure 12 is an exploded perspective view of the battery module shown in Figure 11, and Figure 13 is an exploded perspective view of a cell stack included in the battery module of Figure 11.

[0117] Referring to Figures 11 to 13, the cell stack 110 is housed within the module housing 220, and the specific description of the cell stack 110 is substantially the same as that described in the prior embodiment. A plurality of battery cells 10 can be stacked face to face. If the surface of the outer bag material 20 is slippery, the plurality of battery cells 10 tends to slip easily due to external impact when stacking the plurality of battery cells 10. Therefore, to prevent this and maintain a stable stacked structure of the battery cells 10, an adhesive member 70, such as a sticky adhesive, such as double-sided tape or a chemical adhesive bonded by a chemical reaction during adhesion, can be attached to the surface of the outer bag material 20 to form the cell stack 110.

[0118] In addition, the battery module 200 may also include a damping pad 260 located on at least one of the upper and lower portions of the cell stack 110.

[0119] One or more damping pads 260 are located on at least one of the upper and lower portions of the stacked battery cells 10, and may be interposed between the battery cells 10, if necessary. This damping pad 260 is made of a material whose volume changes easily depending on the external pressure force, for example, a sponge or a non-woven fabric.

[0120] Additionally, an insulating plate 270 located in at least one of the upper and lower portions of the cell stack 110 may also be included.

[0121] The insulating plate 270 is located on at least one of the upper and lower portions of the stacked battery cells 10 and, of course, on the outer side of the damping pad 260 when the damping pad 260 is mounted, thereby pressurizing all surfaces of the battery cells 10 evenly and at the same time preventing electricity from flowing between the metal module housing 220 and the battery cells 10. The insulating plate 270 is preferably made of plastic to reduce weight and insulate the battery module 200.

[0122] As shown in Figures 11 and 12, the module housing 220 is configured to include a pair of side plates 230 located on either side of the cell stack 110, a top plate 240 covering the upper portion of the cell stack 110, and a base plate 250 supporting the cell stack 110.

[0123] The battery module 200 may further include a PC sheet 160 and a mica sheet 170 between the side plate 230 and the side of the cell stack 110, as described above.

[0124] The base plate 250 is a U-shaped frame structure capable of wrapping around and securing the lower end of the side plate 230 from the outside. The base plate 250 can be converted into a U-shaped frame structure by bending both ends of a plate. The bending configuration can be implemented in various ways, such as pressing or profiling.

[0125] The top plate 240 and the side plate 230 can be connected to each other to form a U-shaped frame structure. The top plate 240 and the side plate 230 can form a U-shaped frame structure by welding, gluing, snapping, hooking, or screwing their separate structures together. Alternatively, as with the manufacturing method for the base plate 250, the top plate 240 and the side plate 230 can be made by bending both ends of a plate. In this case, the side plate 230 can be configured to extend downwards from both ends of the top plate 240.

[0126] The battery module 200 has a module 200a opening formed on one side in the longitudinal direction. The module 200a opening may also be formed on the other side of the battery module 200 in the longitudinal direction. Ventilation gas generated inside the battery module 200 can be discharged through the module 200a opening. In this embodiment, the module 200a openings are formed at the front and rear ends of the battery cell 10 in the longitudinal direction, respectively.

[0127] The battery module 200 may further include a bus bar frame assembly 290 that covers the module opening 200a formed on one side of the module housing 220 in the longitudinal direction.

[0128] The pair of side plates 230 has a spark direction change portion 230a formed by bending one end in the longitudinal direction towards the cell stack 110.

[0129] The module opening 200a formed on one side of the module housing 220 in the longitudinal direction is formed between a pair of spark direction change portions 230a provided on each of the pair of side plates 230. The electrode conductor 30 of the battery cell 10 can be exposed to the outside of the module housing 220 through the module opening 200a formed between a pair of spark direction change portions 230a.

[0130] Figure 14 is an exploded perspective view of some components located at the rear of the battery module in Figure 11. Figure 15 is an exploded perspective view of some components located at the front of the battery module in Figure 11.

[0131] Referring to Figures 14 and 15, the module housing 220 may further include a clamping frame 232 that connects a pair of spark direction change portions 230a and has an empty central area.

[0132] The module opening 200a provided in the module housing 220 of this disclosure may be formed on both sides of the module housing 220 in the longitudinal direction. In this case, the pair of spark direction change portions 230a may also be provided on either side of the module housing 220 in the longitudinal direction.

[0133] The busbar frame assembly 290 includes a busbar frame 292 and at least one busbar 294. The busbar frame assembly 290 can be supplied in a pair, in which case each of the pair of busbar frame assemblies 290 covers a module 200a opening formed on one side in the longitudinal direction of the module 220 housing and a module 200a opening formed on the other side.

[0134] The bus bar frame 292 covers the module opening 200a formed in the module housing 220, has a plurality of frame slots 292a through which the electrode conductors 30 of battery cell 10 pass and is made of an insulating material.

[0135] The bus bar frame 292 has a shape corresponding to one end and/or the other end in the longitudinal direction of the module housing 220 and is in close contact with the module housing 220. When the module housing 220 is provided with the clamping frame 232, as described above, the bus bar frame 292 is in close contact with the spark direction change portion 230a and the clamping frame 232.

[0136] The bus bar 294 is arranged on the outer surface of the bus bar frame 292 and is coupled to the electrode conductor 30 that passes through the frame slot 292a, thereby electrically connecting the plurality of battery cells 10. The bus bar 294 has a bus slot 294a through which the electrode connector 30 passes, and can be made of a metallic material having the form of a flat plate. In this case, the bus slot 294a and the frame slot 292a can be formed in corresponding positions to each other.

[0137] The spark direction change portion 230a and the clamping frame 232 can be deformed to catch flares, sparks, and the like. In this case, it is obvious that the bus bar frame 292 can also be modified to correspond to the modified appearance.

[0138] Figure 16 is a partially cut perspective view of the battery module of Figure 11, and Figure 17 is a cross-sectional view parallel to the longitudinal direction of the battery module of Figure 11.

[0139] Referring to Figures 11 to 17, in describing the battery module 200 assembly process including the configuration described above, an insulating plate 270, a damping pad 260, a plurality of battery cells 10, a damping pad 260, and an insulating plate 270 are stacked in that order to prepare the cell stack 110, and the electrode conductors 30 of the battery cells 10 pass through the frame slot 292a of the bus bar frame 292. This time, it should be noted that the resealing portions 50 of the battery cells 10 are distributed on the left and right sides, as described above. Next, the electrode conductors 30 pass through the busbar slot 294a of the busbar 294, which is bent and secured by a known joining means, such as welding.

[0140] The cell stack 110 prepared in this way is housed in a form surrounded by a base plate 250, a top plate 240, and a pair of side plates 230. This time, the top plate 240 and the pair of side plates 230 are combined to form a U-shaped frame structure, and this U-shaped frame structure surrounds both sides and the top surface of the cell stack 110, and the front, rear, and bottom surfaces are open while housing the cell stack 110.

[0141] The base plate 250 is attached to the U-frame in order to surround the lower end of the side plate 230 from the outside. The attachment may be welded, but in this embodiment, a strap attachment 252 and a bolt attachment 254 are illustrated.

[0142] The bus bar frame 292 is in close contact with the spark direction change portion 230a and the clamping frame 232, and the bus bar frame 292 serves to cover the module opening 200a of the module housing 220.

[0143] In particular, the movement path of the ventilation gas and the spark in the battery module 200 can be described by reference to figure 17.

[0144] Referring to Figure 17, the battery module 200 of this disclosure includes a spark direction change portion 230a, as described above, so that the high-temperature sparks emitted during the venting of battery cell 10 cannot be expelled outside the module housing 220 along the longitudinal direction of the module housing 220. That is, when battery cell 10 is vented, the high-temperature sparks expelled through both sides in the direction of the width of each battery cell 10 forming the cell stack 110, i.e., through the alternately arranged resealing portions 50, move to one end and/or the other end in the longitudinal direction of the battery module 200, and then the direction of movement is changed to a direction toward the cell stack 110 (see the direction of the dotted arrow shown in Figure 17). Additionally, since the flames and sparks are trapped in space by the spark direction change portion 230a, they cannot escape to the outside, and their movement may also be restricted in the direction where the electrode conductors 30 are located, thus blocking direct contact with the electrode conductors 30. In this way, the spark direction change portion 230a implements a spark cavity structure.

[0145] When thermal runaway occurs in a specific battery cell, flames, sparks, high-pressure vent gases, and intense heat are expelled, and the coexistence of these with oxygen and combustible materials can cause a fire or explosion. The side plate 230 of the battery module 200 of this disclosure prevents thermal runaway products, such as flames and sparks, from protruding outside the module housing 220, and discharges vent gas and heat through the module opening 200a. In this process, the charged air inside the module housing 220 is also discharged, so that flames are not generated.

[0146] In the present disclosure, the reseal portion 50 of battery cell 10 is stacked in a zigzag pattern to prevent it from tilting in one direction, thus dispersing a large number of high-temperature, high-pressure sparks and flares emitted by the cell's thermal runaway, thereby reducing the pressure. Consequently, a blocking effect is produced against auto-ignition and explosion generated by contact with the hydrogen and oxygen in the surrounding vent gas. Furthermore, for example, assuming the thermal runaway occurs in a specific battery cell 10 where the reseal portion 50 is located on the left side, since the first edge portion E1 is positioned on the left side in Figures 16 and 17, the flares or sparks gather in a blocked state in the space located on the left side, especially in the space surrounded by the spark direction change portion 230a on the left side. Therefore, they do not move forward or backward, where bus bar 294 is located, and they also cannot move to the right side of battery cell 10. On the other hand, since module housing 220 and cell stack 110 do not maintain a completely airtight state, the generated vent gas is discharged through module opening 200a in the vicinity of bus bar frame 292.

[0147] As a result, even if a thermal event occurs in any one of the battery cells, there may be a lack of oxygen required for ignition inside the module housing 220 because the air is discharged to the outside along with the ventilation gas, and combustible materials may be trapped because they are not discharged to the outside of the module housing 220, and furthermore, hot heat may be discharged together when the air is discharged to keep it below the ignition point, thus preventing a fire from occurring.

[0148] As such, by including the module housing 220 that implements the spark cavity, the fire safety of the battery module 200 is increased. In addition, according to the distributed arrangement of the resealing portion 50 unique to this disclosure, if the temperature of the module housing 220 is controlled to a temperature at which auto-ignition does not occur, it is possible to prevent an internal transition situation, following a thermal runaway, from leading to explosive ignition.

[0149] Furthermore, flames can be completely blocked within the battery pack that includes this. The 100 and 200 battery modules having the configuration described above can form a battery pack, housed or not in a separate pack casing. Additionally, the battery module or battery pack can be used in various installations or devices that include high-capacity power sources, such as an ESS, electric vehicles, hybrid vehicles, plug-in hybrid electric vehicles, and the like.

[0150] Figure 18 is a schematic view of a battery pack including a battery module in accordance with this disclosure.

[0151] As shown in Figure 18, a plurality of battery modules 100 or 200 can be arranged adjacent to each other along the width direction to form a battery pack 300. The battery pack 300 can further include a BMS assembly 310 coupled to one side of the battery modules 100, 200 in the width direction. The battery pack 300 can also include a conduit 320 coupled to one or both sides of the battery pack 300 in the length direction. The battery pack 300 can also include a pack housing (not shown) that houses these battery modules 100, 200.

[0152] The BMS 310 assembly can be coupled to one side in the width direction of a module assembly consisting of a plurality of battery modules 100, 200 arranged adjacent to each other. Although not shown in detail in the drawings, the BMS 310 assembly includes at least one battery management system (BMS) that controls the charging/discharging of the plurality of battery modules 100, 200. The BMS 310 assembly can also include a BMS frame coupled to the BMS. The BMS frame can be attached to the module assembly and/or conduit 320. Conduit 320 is separated longitudinally from battery modules 100 and 200, forming a pack flow path (not shown) between battery modules 100 and 200 and conduit 320. Specifically, in the case of battery module 200, it is separated from the module opening 200a. Conduit 320 has an opening formed on one or both sides in the width direction. This opening communicates with the pack flow path. Therefore, the vent gas discharged to the outside of battery module 200 along the module opening 200a formed in battery module 200 moves to one or both sides in the direction of the duct width 320 along the pack flow path and is then discharged to the outside of battery pack 300 through the duct opening. An ESS, which has recently attracted attention, is a device that can maximize energy efficiency by storing generated electricity in a battery and supplying it to consumers when needed. In an ESS, several battery modules form a rack, and dozens to hundreds of racks form a system. It is also used in conjunction with uninterruptible power supply (UPS) systems, which ensure a stable power supply in response to sudden power outages or anomalies, and solar power generation systems, which are energy-generating devices that convert sunlight into electrical energy. The 100, 200 battery modules according to this disclosure are particularly suitable as battery modules for ESS because they are excellent at preventing ignition.

[0153] Figure 19 is a schematic view of an ESS including a battery module according to this disclosure. The ESS 400, according to this disclosure, may include a battery module 100 or 200. Furthermore, the ESS 400 may include a plurality of battery modules 100 and 200, according to one embodiment of this disclosure, which are electrically connected to each other to provide a large energy capacity. Additionally, the ESS 400, according to one embodiment of this disclosure, may also include various other ESS components known at the time of filing this disclosure. Moreover, this ESS 400 can be used in various locations or devices, such as a smart grid system or an electric charging station. In particular, the ESS 400, according to an embodiment of the present disclosure, may be a residential (building) ESS for home or office used to store energy in a residential house, home office, building, or the like.

[0154] Meanwhile, terms indicating directions, as used herein, such as top, bottom, left, right, front, and rear, are used only for convenience of description, and it is obvious to those skilled in the art that the term may change depending on the position of the item indicated or of an observer.

[0155] The present disclosure has been described above in relation to a limited number of embodiments and drawings, but the present disclosure is not limited to them and it is obvious to those skilled in the art that various modifications and changes may be made within the technical aspects of the present disclosure and the equivalent scope of the appended claims.

[0156] [Explanation of reference symbols]

[0158] 10: battery cell 40: sealing portion

[0159] 50: resealing portion 100, 200: battery module

[0160] 110: cell stack 120, 220: module housing

[0161] 130, 230: side plate 135: heat dissipation fin

[0162] 140, 240: top plate 150, 250: base plate

[0163] 160: PC sheet 170: mica sheet

[0164] 180: heat spreader 230a: spark direction change portion 232: clamping frame 260: damping pad

[0165] 270: insulating plate 290: bus bar frame assembly

[0166] 292: busbar frame 294: busbar

[0167] 300: battery pack 400: ESS

Claims (11)

1. CLAIMS 1. A battery module (200) comprising a cell stack (110) formed by stacking a plurality of battery cells (10) comprising a receiving portion (R) housing an electrode assembly, a first edge portion (E1) and a second edge portion (E2) along the longitudinal direction around the receiving portion (R), and a third edge portion (E3) and a fourth edge portion (E4) along the width direction, in the vertical direction with the receiving portions (R) oriented towards each other, and a module housing (220) that houses the cell stack (110), wherein each battery cell (10) comprises a resealable portion (50) in the first edge portion (E1), and comprises a sealing portion (40) or an unsealed portion in the second edge portion (E2), and the first edge portion (E1) and the second edge portion (E2) are alternately positioned along the vertical direction on both sides of the cell stack (110), wherein each battery cell (10) is a pouch-type battery cell comprising an outer pouch material (20), an electrode assembly, and a pair of electrode conductors (30) protruding from the outer pouch material (20), wherein the resealing portion (50) refers to a sealing portion resulting from a resealing operation performed after the battery cell degassing process (10) and has a weaker sealing resistance than the sealing portion (40), wherein the unsealed portion refers to a portion where the outer bag material (20) is folded, wherein the module housing (220) comprises a pair of side plates (230) located on both sides of the cell stack (110), and Each side plate (230) and the cell stack (110) are separated to form a space portion, wherein the pair of side plates (230) comprises a pair of spark direction change portions (230a) formed by bending one end in the longitudinal direction towards the cell stack (110). 2. The battery module (200) according to claim 1, further comprising a polycarbonate (PC) sheet (160) and a mica sheet (170) between the module housing (220) and the side of the cell stack (110). 3. The battery module (200) according to claim 1, wherein a first edge portion (E1) of approximately half of the plurality of battery cells (10) is oriented towards one of the side plates (230), and a first edge portion (E1) of the remaining battery cells (10) is oriented towards the other of the side plates (230). 4. The battery module (200) according to claim 1, wherein the module housing (220) further comprises a top plate (240) covering the upper portion of the cell stack (110), and the side plates (230) have a greater thickness than the top plate (240). 5. The battery module (200) according to claim 1, wherein the module housing (220) further comprises a top plate (240) covering the upper portion of the cell stack (110), and a base plate (250) supporting the cell stack (110). 6. The battery module (200) according to claim 1, which further comprises a shock-absorbing pad (260) located on at least one of the upper portion and the lower portion of the cell stack (110). 7. The battery module (200) according to claim 1, which further comprises an insulating plate (270) located in at least one of the upper and lower portions of the cell stack (110). 8. The battery module (200) according to claim 1, wherein the module housing (220) further comprises a top plate (240) covering the upper portion of the cell stack (110), the module housing (220) has a module opening formed in the longitudinal direction and The module housing (220) further comprises a bus bar frame assembly (290) that covers the module opening. 9. The battery module (200) according to claim 1, which further comprises a clamping frame (232) that connects the pair of spark direction change portions (230a) and has an empty central area. 10. A battery pack (300) comprising a battery module (200) according to any one of claims 1 to 9. 11. An energy storage system (400) comprising a battery module (200) according to any one of claims 1 to 9.