Battery module and battery pack including same

Abstract

Provided is a battery pack comprising: a plurality of battery modules, each including a plurality of battery cells; and a pack housing accommodating the plurality of battery modules. At least one of the plurality of battery modules includes: a cell stack in which the plurality of battery cells are stacked; a side plate that is disposed on one side of the cell stack and coupled to the pack housing; and an elastic member disposed between the cell stack and the side plate. The elastic member includes: a frame part supported by the side plate; and a plurality of elastic ribs that extend from the frame part in a direction inclined relative to the stacking direction of the plurality of battery cells, and elastically deform and apply an elastic force to the cell stack as the cell stack expands.

Description

Battery module and battery pack including same

[0001] The present invention relates to a battery module and a battery pack including the same.

[0002] Secondary batteries can be charged and discharged, so they are widely used in mobile devices such as digital cameras, cell phones, and laptops. In particular, they have recently been attracting attention as an energy source for electric vehicles and energy storage systems (ESS).

[0003] During repeated charging and discharging of secondary batteries, gas may be generated within the battery cells. This gas can cause the cells to expand and contract, a phenomenon known as swelling. This swelling can reduce the charge and discharge performance of the secondary battery and deform the shape of the case, potentially compromising structural rigidity.

[0004] Meanwhile, secondary batteries require a certain initial pressure to be maintained before use, but conventional compression pads alone have limitations in forming an initial pressure greater than a certain size.

[0005] Accordingly, there is a need for the development of a pressurizing structure that can control the swelling phenomenon that occurs during charging and discharging while being able to apply an appropriate initial pressurizing force.

[0006] The present invention has been devised to solve at least some of the problems of the prior art as described above, and provides a battery module and battery pack capable of applying an appropriate initial pressure to a battery cell and controlling a swelling phenomenon that occurs during charging and discharging.

[0007] In order to achieve the above object, in embodiments of the present invention, a battery module is provided, including a cell stack in which a plurality of battery cells are stacked, an elastic member arranged on one side of the cell stack and configured to apply surface pressure to the cell stack in a direction parallel to the stacking direction of the plurality of battery cells, and a module housing in which the cell stack and the elastic member are accommodated, wherein the elastic member includes a frame portion supported by the module housing and a plurality of elastic ribs extending in a direction inclined with respect to the stacking direction of the plurality of battery cells from the frame portion and configured to apply an elastic force to the cell stack by elastically deforming as the cell stack expands.

[0008] In embodiments, at least one elastic rib of the plurality of elastic ribs includes a first pressurizing portion extending from the frame portion, and a second pressurizing portion connected to an end of the first pressurizing portion, wherein a width of the second pressurizing portion may be smaller than a width of the first pressurizing portion.

[0009] In embodiments, a plurality of elastic ribs in the elastic member may be symmetrically arranged with respect to a central axis parallel to the longitudinal direction of the battery cell.

[0010] In embodiments, at least one of the first pressurized portion or the second pressurized portion may have a width that gradually decreases as it approaches the central axis.

[0011] In embodiments, the first pressurizing portion and the second pressurizing portion may be made of different materials.

[0012] In embodiments, the frame portion is provided as a frame-shaped structure having a pair of long side edges and a pair of short side edges, and a plurality of elastic ribs can be connected to at least one of the pair of long side edges.

[0013] In embodiments, the battery module may further include a compression pad disposed between the plurality of battery cells and the elastic member.

[0014] In embodiments, a battery pack is provided, comprising: a plurality of battery modules each including a plurality of battery cells; and a pack housing accommodating the plurality of battery modules, wherein at least one battery module of the plurality of battery modules comprises a cell stack in which the plurality of battery cells are stacked; a side plate disposed on one side of the cell stack and coupled to the pack housing; and an elastic member disposed between the cell stack and the side plate, wherein the elastic member comprises a frame portion supported by the side plate and a plurality of elastic ribs extending in a direction oblique to a stacking direction of the plurality of battery cells from the frame portion and configured to elastically deform as the cell stack expands and apply an elastic force to the cell stack.

[0015] In embodiments, at least one battery module may further include a pressure plate interposed between the cell stack and the elastic member.

[0016] In embodiments, at least one battery module may further include a connecting member connecting the pressure plate and the side plate.

[0017] In embodiments, at least one battery module may further include a compression pad disposed between the pressure plate and the plurality of battery cells.

[0018] In embodiments, in at least one battery module, a lower surface of the cell stack may be exposed to the pack housing.

[0019] In embodiments, at least one elastic rib of the plurality of elastic ribs includes a first pressurizing portion extending from the frame portion, and a second pressurizing portion connected to an end of the first pressurizing portion, wherein a width of the second pressurizing portion may be smaller than a width of the first pressurizing portion.

[0020] In embodiments, the frame portion is provided as a frame-shaped structure having a pair of long side edges and a pair of short side edges, and a plurality of elastic ribs can be connected to at least one of the pair of long side edges.

[0021] According to embodiments, a battery module and battery pack can be implemented that can apply an appropriate level of initial pressure to a battery cell while effectively controlling a swelling phenomenon that occurs during charging and discharging.

[0022] FIG. 1 is a perspective view of a battery pack including a battery module according to embodiments.

[0023] Figure 2 is an exploded perspective view of a battery module according to embodiments.

[0024] FIG. 3 is an exploded perspective view of a cell stack included in a battery module according to embodiments.

[0025] FIG. 4 is an exploded perspective view of a pressurized assembly included in a battery module according to embodiments.

[0026] Figure 5 is a perspective view of an elastic member included in a pressurized assembly.

[0027] Fig. 6 is a cross-sectional view according to part II' of Fig. 5.

[0028] Figure 7 is a graph illustrating the pressure applied to the cell stack by an elastic member included in the pressurized assembly.

[0029] Figure 8 is an exemplary cross-sectional view of a battery module according to embodiments.

[0030] FIG. 9 is an exemplary cross-sectional view of a battery module according to embodiments.

[0031] Figure 10 is an exploded perspective view of a battery module according to another embodiment.

[0032] Before going into the detailed description of the present invention, it should be noted that the terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his own invention in the best way. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0033] The same reference numbers or symbols used in each drawing attached to this specification represent parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they do not necessarily represent a single embodiment.

[0034] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprises" or "comprises" should be understood to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] In addition, in the description below, expressions such as top, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and it is noted in advance that they may be expressed differently if the direction of the object in question changes.

[0036] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0037] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the spirit of the present invention is not limited to the presented embodiments. For example, those skilled in the art who understand the spirit of the present invention may propose other embodiments within the spirit of the present invention by adding, modifying, or deleting components, etc., but such embodiments will also be considered to be within the spirit of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0038] FIG. 1 is a perspective view of a battery pack (1) including a battery module (10) according to embodiments.

[0039] Referring to FIG. 1, a battery pack (1) according to embodiments may include a plurality of battery modules (10) and a pack housing (20) in which the plurality of battery modules (10) are accommodated.

[0040] A plurality of battery modules (10) can be accommodated in a pack housing (20). The pack housing (20) can include a lower plate (21) and a plurality of support beams (22). The battery modules (10) can be installed in an inner accommodation space formed by the lower plate (21) and the plurality of support beams (22). Meanwhile, although not shown in FIG. 1, the pack housing (20) can further include an upper cover that is arranged on top of the plurality of support beams (22) to close the accommodation space of the pack housing (20).

[0041] The lower plate (21) can form the lower surface of the pack housing (20). In various embodiments, the lower plate (21) can be provided as a square plate-shaped member or a polygonal plate-shaped member other than a square, but the shape of the lower plate (21) is not necessarily limited thereto.

[0042] A plurality of battery modules (10) can be mounted on the upper portion of the lower plate (21).

[0043] The lower plate (21) may be formed of a rigid metal material. For example, at least a portion of the lower plate (21) may include aluminum. When the lower plate (21) includes aluminum, the excellent thermal conductivity of aluminum allows heat energy generated in the battery module (10) to be quickly dissipated to the outside of the battery pack (1).

[0044] The support beam (22) may be connected to the lower plate (21). For example, referring to FIG. 1, the support beam (22) may be arranged on the upper surface of the lower plate (21) to partition the internal space of the pack housing (20). One or more battery modules (10) may be accommodated in the space partitioned by the support beam (22). For example, at least some of the plurality of support beams (22) may form a side surface of the pack housing (20).

[0045] Figure 2 is an exploded perspective view of a battery module (10) according to embodiments.

[0046] FIG. 3 is an exploded perspective view of a cell stack (100) included in a battery module (10) according to embodiments.

[0047] Referring to FIGS. 2 and 3, a battery module (10) according to embodiments may be configured to output or store electrical energy by including one or more battery cells (110).

[0048] A plurality of battery cells (110) included in a battery module (10) may be stacked in one direction (e.g., the Y-axis direction of FIG. 2) to form at least a portion of a cell stack (100). In the following description, the stacking direction of the battery cells (110) is referred to as a 'cell stacking direction'.

[0049] In embodiments, the battery cell (110) may be a secondary battery capable of being charged and discharged.

[0050] For example, referring to FIGS. 2 and 3, the battery cell (110) may be a pouch-type secondary battery in which an electrode assembly is housed inside a sealed pouch.

[0051] In a pouch-type secondary battery, the electrode assembly and electrolyte may be housed within a pouch formed by processing one or more outer layers. The outer layer forming the pouch may be composed of an aluminum laminated film, but the specific material is not limited thereto.

[0052] However, the shapes of the battery cells (110) illustrated in FIGS. 2 and 3 are merely exemplary, and the battery cells (110) included in the battery modules (10) according to the embodiments are not limited to pouch-type secondary batteries. For example, the battery cells (110) may be configured as square secondary batteries in which an electrode assembly is accommodated inside a square case having a predetermined rigidity.

[0053] For example, the battery cell (110) may be composed of an all-solid-state battery.

[0054] Meanwhile, in various embodiments, the cell stack (100) may further include a plate-shaped protective member capable of protecting a plurality of battery cells (110).

[0055] For example, the plate-shaped protective member may include a compression pad (120) that can apply a predetermined surface pressure to the battery cell (110) to prevent the battery cell (110) from swelling during the charging and discharging process. The compression pad (120) may include at least one of polyurethane, silicone, and rubber (EPDM). The compression pad (120) may pressurize the battery cell (110) by elastic force or be compressed by the battery cell (110).

[0056] As illustrated in FIG. 3, a plurality of compression pads (120) and a plurality of battery cells (110) may be stacked along a cell stacking direction (e.g., Y-axis direction). For example, the compression pads (120) and the battery cells (110) may be alternately stacked along the cell stacking direction. For example, the plurality of battery cells (110) may be arranged to be interposed between the plurality of compression pads (120). For example, at least some of the plurality of compression pads (120) may be arranged at the outermost end of the cell stack (100), and at least some of the other may be arranged between the plurality of battery cells (110).

[0057] However, in various embodiments of the present disclosure, the number or stacking method of the compression pads (120) and battery cells (110) constituting the cell stack (100) is not limited to that shown in FIG. 3, and in the embodiments, the number or stacking method of the plate-shaped protective member and battery cells (110) constituting one cell stack (100) may be varied as needed.

[0058] The battery module (10) may include a busbar assembly (300) electrically connected to the battery cells (110) of the cell stack (100).

[0059] The busbar assembly (300) may be arranged on at least one side of the cell stack (100) to electrically connect the battery cells (110) to each other. For example, the busbar assembly (300) may be provided as a pair, with one busbar assembly arranged on each end of the cell stack (100). However, a pair of busbar assemblies (300) may be connected to each other to form a single component.

[0060] In the battery module (10), an end cover (400) may be placed on the outside of the busbar assembly (300). The end cover (400) may include a material having rigidity (e.g., a metal such as aluminum or a resin compound) to protect the cell stack (100) from external impact. Although not shown in the drawing, an insulating cover (not shown) including an insulating material may be placed between the end cover (400) and the busbar assembly (300) to prevent the end cover (400) and the busbar assembly (300) from being electrically short-circuited.

[0061] Meanwhile, in embodiments, the battery module (10) may further include a pressurizing assembly (500) that pressurizes the cell stack (100).

[0062] The pressurizing assembly (500) may be provided as a pair and may be arranged on both sides of the cell stack (100). For example, the pair of pressurizing assemblies (500) may be arranged spaced apart from each other at both ends of the cell stack (100) along the cell stacking direction with the cell stack (100) interposed therebetween. Accordingly, any two sides of the cell stack (100) may face the pressurizing assembly (500), and the other two sides may face the busbar assembly (300) and the end cover (400).

[0063] When charging and discharging of a battery cell (110) is repeated, a swelling phenomenon occurs in which the battery cell (110) expands due to gas generated inside the battery cell (110), which may result in a deterioration in the electrical performance of the battery cell (110).

[0064] To suppress this swelling phenomenon, the pressurizing assembly (500) can be configured to apply a surface pressure to the cell stack (100) that resists the expansion pressure of the cell stack (100), thereby suppressing the swelling phenomenon of the battery cell (110).

[0065] FIG. 4 is an exploded perspective view of a pressurized assembly (500) included in a battery module (10) according to embodiments.

[0066] Referring to FIGS. 2 and 4, a pressurizing assembly (500) according to embodiments may include a side plate (510) coupled to a pack housing (20), a pressurizing plate (530) spaced apart from the side plate (510) along the cell stacking direction, and an elastic member (520) interposed between the side plate (510) and the pressurizing plate (530).

[0067] The side plate (510) can be configured to be coupled to the pack housing (20) and, together with the end cover (400), can form the outer side of the battery module (10). For example, the side plate (510) and the end cover (400) can function as a module housing (510, 400) for the battery module (10), and it can be understood that components such as the cell stack (100) and the elastic member (520) are accommodated in the inner space of the module (10) formed by the side plate (510) and the end cover (400).

[0068] The side plate (510) and the pressure plate (530) are interconnected through a connecting member (540), and may have a structure in which an elastic member (520) is sandwiched between them.

[0069] The connecting member (540) can connect the side plate (510) and the pressure plate (530) and at the same time serve as a stopper that sets the maximum gap (e.g., initial gap) between the two members.

[0070] For example, the connecting member (540) allows the elastic member (520) to remain interposed between the side plate (510) and the pressing plate (530) while the pressing assembly (500) is assembled with other components of the battery module (10), such as the cell stack (100) or the end cover (400).

[0071] The elastic member (520) can be elastically deformed as the cell stack (100) expands. The elastic member (520) can press the cell stack (100) in the cell stacking direction (e.g., Y-axis direction) by elastic force. The elastic member (520) is made of a material (e.g., metal or plastic) having a predetermined stiffness, and can be configured to be elastically deformed by an external force.

[0072] The pressure plate (530) is placed between the cell stack (100) and the elastic member (520), and can transmit the elastic force generated from the elastic member (520) to the cell stack (100). In this process, since the pressure plate (530) is configured in a flat plate shape, the elastic force of the elastic member (520) can be evenly spread on one surface of the cell stack (100) (e.g., the outermost surface in the cell stacking direction of the cell stack (100), so that an equal surface pressure can be applied to the cell stack (100).

[0073] Meanwhile, one or more compression pads (120) may be interposed between the pressure plate (530) and the battery cell (110), so that even if the surface of the battery cell (110) is uneven, the compression pads (120) can act as a buffer to form a uniform surface pressure on the battery cell (110).

[0074] In one embodiment, the side plate (510) may include a coupling portion (511) that is coupled to the pack housing (20). For example, a fastening member such as a bolt may be used for coupling between the coupling portion (511) and the pack housing (20).

[0075] Meanwhile, in the embodiment, the cell stack (100) included in the battery module (10) may have four sides covered by an end cover (400) or a pressurizing assembly (500), but its upper and lower surfaces may be exposed to the outside of the battery module (10).

[0076] For example, referring to FIGS. 1 and 2, the battery module (10) may omit a separate cover member covering the upper and lower surfaces of the cell stack (100), and thus the upper and lower surfaces of the cell stack (100) may be exposed to the pack housing (20).

[0077] According to this structure, the heat energy generated from the battery cell (110) can be transferred to the pack housing (20) more quickly, so that the heat dissipation efficiency of the battery module (10) can be increased.

[0078] In addition, since the separate cover member covering the upper and lower surfaces of the cell stack (100) is omitted, the size of the battery cell (110) can be increased by the amount of space secured, or other components can be arranged, thereby increasing the energy density or space efficiency within the limited internal space of the pack housing (20).

[0079] The 'battery module' according to the present disclosure may be understood as various forms of energy storage devices configured by assembling a plurality of battery cells. For example, in the battery module and battery pack including the same according to the present disclosure, the 'battery module' may be understood as a concept that includes not only the generally referred to battery module, but also a cell assembly, cell unit, cell group, cell block, or sub-battery pack for a CTP (cell to pack) or CTC (cell to chassis) structure.

[0080] Hereinafter, the configuration of the pressurizing assembly (500) included in the battery module (10) according to the embodiments will be described in more detail with reference to FIGS. 5 and 6.

[0081] FIG. 5 is a perspective view of an elastic member (520) included in a pressurized assembly (500).

[0082] Fig. 6 is a cross-sectional view according to part II' of Fig. 5.

[0083] In embodiments, the pressurizing assembly (500) may include an elastic member (520) disposed between the side plate (510) and the pressurizing plate (530) to apply surface pressure to the cell stack (100). The elastic member (520) may be elastically deformed as the cell stack (100) expands, and may apply an elastic force to the cell stack (100).

[0084] The elastic member (520) may include a frame portion (521) fixed to the side plate (510), and a plurality of elastic ribs (522) extending from the frame portion (521) and being elastically deformable.

[0085] The frame portion (521) is a portion forming the outer skeleton of the elastic member (520) and may be provided in a shape corresponding to the shape of the battery cell (110). For example, if the battery cell (110) has a rectangular shape with long sides and short sides, the frame portion (521) may be provided in a frame-shaped structure corresponding to this, having a pair of long-side edges (521a) and a pair of short-side edges (521b).

[0086] The frame portion (521) is made of a material having a predetermined rigidity, but may be formed of a material capable of elastic deformation. For example, the frame portion (521) may be made of a metal such as aluminum or a polymer material such as plastic, and may be configured to be elastically deformed by an external force.

[0087] The elastic member (520) may include a plurality of elastic ribs (522) extending from the frame portion (521). The elastic ribs (522) are portions of the elastic member (520) that at least partially contact the pressure plate (530), and may be elastically deformed according to the expansion of the cell stack (100) and may apply surface pressure to the cell stack (100).

[0088] Referring to FIG. 5, a plurality of elastic ribs (522) extend in a direction facing each other from a pair of long edge edges (521a) of a frame portion (521) and may be spaced apart from each other along the longitudinal direction (e.g., X-axis direction) of the long edge edges (521a). Here, the longitudinal direction of the long edge edges (521a) may be a direction parallel to the longitudinal direction of the battery cell (110). As the elastic ribs (522) are arranged along the long edge edges (521a) of the frame in this way, a greater number of elastic ribs (522) can be arranged in an inner region of the frame portion (521) (e.g., a region surrounded by a pair of long edge edges (521a) and a pair of short edge edges (521b)), thereby enhancing the function of the pressurizing assembly (500).

[0089] Each elastic rib (522) may be formed to extend from the frame portion (521) toward the cell stack (100) in a form that protrudes at least partially. For example, referring to FIG. 6, the elastic rib (522) may extend obliquely from the frame portion (521) in a direction inclined with respect to the cell stacking direction (Y-axis direction). According to this structure, the end of the elastic rib (522) may be arranged in front of the long edge (521a) of the frame in the direction toward the cell stack (100) (Y-axis direction). When the cell stack (100) expands, the expansion pressure of the cell stack (100) is applied from the end of the elastic rib (522), and the cell stack (100) may be gradually elastically deformed from the end of the elastic rib (522) to the long edge (521a) of the frame.

[0090] As illustrated in FIG. 5, in one embodiment, a plurality of elastic ribs (522) may be symmetrically arranged with respect to a central axis (CA) of the frame portion (521). For example, the central axis (CA) may be substantially parallel to the longitudinal direction (X-axis direction) of the battery cell (110) (e.g., the long side direction of the battery cell (110). When a plurality of elastic ribs (522) are symmetrically arranged in this manner, it is possible to prevent elastic force from being concentrated in a certain area of ​​the battery cell (110) and to apply an even surface pressure.

[0091] Meanwhile, the elastic member (520) may be configured to pressurize the cell stack (100) with different pressure profiles depending on the degree of expansion of the cell stack (100). For example, the 'pressure profile' may include information on changes in elasticity depending on the degree of expansion of the cell stack (100). To this end, in the embodiment, the elastic rib (522) of the elastic member (520) may include a first pressing portion (522a) and a second pressing portion (522b) having different widths.

[0092] Referring to FIGS. 5 and 6 together, the elastic rib (522) of the elastic member (520) may include a first pressing portion (522a) that protrudes and extends from the frame and a second pressing portion (522b) that is connected to an end of the first pressing portion (522a) and extends in the direction of the central axis (CA).

[0093] The first pressurizing portion (522a) may extend obliquely from the frame in the cell stacking direction (Y-axis direction). A slot portion (SL) may be formed between one first pressurizing portion (522a) and another adjacent first pressurizing portion (522a), whereby each first pressurizing portion (522a) may be individually elastically deformed.

[0094] The second pressurizing portion (522b) can be connected to an end of the first pressurizing portion (522a). The second pressurizing portion (522b) can extend in a direction oblique to the cell stacking direction (Y-axis direction) from the end of the first pressurizing portion (522a).

[0095] Referring to Fig. 6, the end of the second pressurizing portion (522b) may be positioned in front of the end of the first pressurizing portion (522a) in the direction (Y-axis direction) toward the cell stack (100). Therefore, when the cell stack (100) expands, the expansion pressure of the cell stack (100) may be applied from the end of the second pressurizing portion (522b), and an elastic force may be applied to the cell stack (100) while gradually elastically deforming from the second pressurizing portion (522b) to the first pressurizing portion (522a).

[0096] Meanwhile, as illustrated in FIG. 6, the first pressurizing portion (522a) and the second pressurizing portion (522b) may extend in a shape of a gentle curvature, but the specific shape is not limited to that illustrated in the drawing. For example, the first pressurizing portion (522a) and the second pressurizing portion (522b) may extend in a direction inclined with respect to the cell stacking direction from the frame portion (521), but may also extend in a straight line without curvature. For example, the first pressurizing portion (522a) and the second pressurizing portion (522b) may be formed to have different curvatures.

[0097] In embodiments, the elastic rib (522) may be formed to have different widths of the first pressing portion (522a) and the second pressing portion (522b) so as to be able to pressurize the cell stack (100) with different pressure profiles depending on the degree of expansion of the cell stack (100). Here, the 'width' may mean the length in the longitudinal direction (X-axis direction) of the battery cell (110). For example, referring to FIG. 5, the width (w2) of the second pressing portion (522b) of the elastic rib (522) may be formed to be narrower than the width (w1) of the first pressing portion (522a). Accordingly, the second pressurizing portion (522b) can be more easily deformed by an external force than the first pressurizing portion (522a), and the size of the elastic force applied by the second pressurizing portion (522b) can also be formed to be smaller than that of the first pressurizing portion (522a).

[0098] In one embodiment, the first pressurizing portion (522a) and the second pressurizing portion (522b) may be formed so that their widths gradually decrease as they approach the central axis (CA). However, the structures of the first pressurizing portion (522a) and the second pressurizing portion (522b) are not limited to those described above. For example, in another embodiment, the first pressurizing portion (522a) and the second pressurizing portion (522b) may extend with a constant width, or may have the same width.

[0099] In embodiments, the first pressing portion (522a) and the second pressing portion (522b) constituting the elastic rib (522) may be formed of different materials. Accordingly, the elastic rib (522) may pressurize the cell stack (100) with different pressure profiles depending on the degree of expansion of the cell stack (100). For example, in one embodiment, the first pressing portion (522a) may be formed of the same material as the frame portion (521), and the second pressing portion (522b) may be formed of a different material from the first pressing portion (522a). For example, the first pressing portion (522a) may be formed of a polymer resin material such as plastic, and the second pressing portion (522b) may be formed of a metal material such as aluminum. When the second pressing portion (522b) is formed of a metal material, it may generate a higher elastic force than when it is formed of a polymer resin material.

[0100] As the materials of the first pressurizing portion (522a) and the second pressurizing portion (522b) are configured differently, the profiles of elastic force generated in the first pressurizing portion (522a) and the second pressurizing portion (522b) can be formed differently from each other.

[0101] However, in the embodiment, the materials of the first pressurizing portion (522a) and the second pressurizing portion (522b) are not limited to those described above, and various materials having elasticity can be applied without limitation.

[0102] Hereinafter, with reference to FIGS. 7 to 9, the pressure profile applied by the elastic member (520) included in the battery module (10) to the cell stack (100) will be described in more detail.

[0103] FIG. 7 is a graph for explaining the pressure applied to the cell stack (100) by the elastic member (520) included in the pressurized assembly (500).

[0104] Fig. 8 is an exemplary cross-sectional view of a battery module (10) according to embodiments.

[0105] Fig. 9 is an exemplary cross-sectional view of a battery module (10) according to embodiments.

[0106] In the graph of Fig. 7, the horizontal axis may represent the displacement (or degree of deformation) of the elastic member (520) due to the expansion of the cell stack (100). In the graph of Fig. 7, the vertical axis may represent the magnitude of the elastic force generated in the elastic member (520).

[0107] Section D1 of FIG. 7 may be an initial pressure section in which the elastic member (520) applies initial pressure to the cell stack (100) in the initial state before the battery module (10) is normally operated. FIG. 8 may correspond to a cross-sectional view of a state corresponding to section D1 of FIG. 7 in the battery module (10).

[0108] Referring to FIGS. 7 and 8 together, in the D1 section (e.g., initial pressure section), the elastic member (520) applies initial pressure to the cell stack (100) with the elastic force generated by the elastic deformation of the second pressurizing portion (522b), thereby preventing the occurrence of empty spaces due to differences in the thickness of the battery cells (110) or manufacturing tolerances, and ensuring that the battery cells (110) of the cell stack (100) are in close contact with each other.

[0109] In particular, it was difficult to form an appropriate level of initial pressure with only the compression pad (120), but the elastic member (520) according to the embodiment can form an appropriate level of initial pressure by the elastic force generated when the second pressurizing portion (522b) is elastically deformed.

[0110] Section D2 of FIG. 7 may be a driving pressure section in which the elastic member (520) applies surface pressure to the cell stack (100) as the battery module (10) continuously expands while repeating charging and discharging. FIG. 9 is a cross-sectional view of a state corresponding to section D2 of FIG. 7 in the battery module (10). In this section, as the cell stack (100) gradually expands, the first pressing portion (522a) of the elastic member (520) also undergoes elastic deformation, and accordingly, the elastic member (520) applies surface pressure stronger than the initial pressure to the cell stack (100), thereby effectively suppressing the swelling phenomenon of the battery cell (110).

[0111] In embodiments, the width of the first pressing portion (522a) of the elastic member (520) may be greater than the width of the second pressing portion (522b), and thus, the pressure profile according to the increase in displacement in the D2 section may be different from the pressure profile according to the displacement in the D1 section. For example, referring to FIG. 7, the amount of pressure increase according to the displacement in the D2 section, in which the elastic deformation of the first pressing portion (522a) is accompanied in addition to the elastic deformation of the second pressing portion (522b), may be greater than the amount of pressure increase according to the displacement in the D1 section. Accordingly, the elastic member (520) can apply a strong surface pressure corresponding to the expansion of the battery cell (110), thereby more effectively controlling the swelling phenomenon.

[0112] Meanwhile, to prevent excessive surface pressure from being applied to the battery cell (110), the pressure profile in the D2 section can be adjusted to have a value within an appropriate range. For example, referring to FIG. 7, as the cell stack (100) continuously expands, the elastic member (520) can be configured to have a high-rigidity section (D3 section) in which the elastic force rapidly increases according to displacement.

[0113] In the D3 section, excessive surface pressure may be applied to the battery cell (110), which may cause damage to the battery cell (110) or capacity degradation. To prevent this, the elastic member (520) is formed to have a plurality of gentle elastic force sections (i.e., D1 section and D2 section) implemented by the first pressurizing portion (522a) and the second pressurizing portion (522b) having different widths before entering the high-rigidity section, thereby forming a wide range of appropriate pressure sections before the high-rigidity section.

[0114] For example, a plurality of elastic ribs (522) formed of pressurized portions (522a, 522b) having different widths can form a linear pressure profile proportional to the displacement in each pressure section, thereby preventing a nonlinear rapid pressure increase due to an increase in displacement, thereby significantly increasing the section in which a surface pressure of an appropriate range (e.g., a pressure lower than the D3 section) is applied to the battery cell.

[0115] In the past, it was difficult to set the elasticity change for each section according to the degree of deformation using only the compression pad provided in the cell stack, and there was a problem in that the compression pad applied excessive surface pressure to the battery cell because the pressure increased rapidly after the initial pressure section.

[0116] On the other hand, since the elastic member (520) according to the embodiment can set the rate of increase in elastic force differently in the initial pressure section and the subsequent driving pressure section, it can be configured to apply an appropriate elastic force according to each situation. In addition, since the displacement section in which an appropriate level of elastic force is applied can be formed as long as possible by a plurality of elastic ribs (522) formed of pressure portions (522a, 522b) having different widths, it is possible to prevent excessive surface pressure from being applied to the battery cell (110), thereby improving the lifespan of the battery cell (110).

[0117] In addition, since the elastic member (520) according to the embodiments can appropriately respond to the initial pressure section and the driving pressure section described above as a single member, there is no need to arrange a plurality of pressure members inside the battery module (10), and thus a battery module (10) that is structurally simple and can increase space efficiency can be implemented.

[0118] Meanwhile, the elastic member (520) according to the embodiments can be modified in various ways to change the width of the first pressurizing portion (522a) and the second pressurizing portion (522b), and accordingly, the pressure profile in the initial pressure section and the driving pressure section can be formed in various ways, so that an elastic member (520) having an optimal shape corresponding to the specifications or usage environment of the battery module (10) can be provided.

[0119] Hereinafter, a battery module (30) according to another embodiment will be described with reference to FIG. 10.

[0120] Fig. 10 is an exploded perspective view of a battery module (30) according to another embodiment.

[0121] Referring to FIG. 10, in another embodiment, a battery module (30) may include a housing (31) having an internal space, a plurality of battery cells (110) accommodated in the internal space, and an end cover assembly (32) including a conductive bus bar coupled to at least one side of the housing (31) and electrically connected to the battery cells (110).

[0122] The housing (31) provides an internal space in which one or more cell stacks (100) can be accommodated. The housing (31) may be formed of a material having a predetermined rigidity to protect the cell stacks (100) and other electrical components accommodated in the internal space from external impact. For example, the housing (31) may include a metal material such as iron, stainless steel, or aluminum.

[0123] The housing (31) may include a lower frame (31a) and an upper cover (31b) that are coupled to each other. The lower frame (31a) may be provided with a U-shaped structure in which the cell stack (100) is mounted and the upper and both sides are open, and the upper cover (31b) may be configured to be coupled to the open upper portion of the lower frame (31a) so as to cover the upper surface of the cell stack (100).

[0124] However, the structure of the housing (31) is not limited thereto, and may be of any shape as long as it has an internal space capable of accommodating at least one cell stack (100). For example, the housing (31) may be configured as an integral monoframe in which an upper cover (31b) and a lower frame (31a) are integrally formed and both sides are open.

[0125] An end cover assembly (32) may be coupled to one open side of the housing (31). For example, as illustrated in FIG. 10, the end cover assemblies (32) may be provided as a pair and coupled to each of the open sides of the housing (31).

[0126] A cell stack (100) can be accommodated inside the housing (31). Here, the cell stack (100) corresponds to the cell stack (100) described above with reference to FIGS. 1 to 9, and therefore, for a detailed description thereof, reference may be made to the description of the cell stack (100) of FIGS. 1 to 9.

[0127] An elastic member (520) may be placed between the cell stack (100) and the housing (31). Here, the elastic member (520) has the same structure and function as the elastic member (520) described with reference to FIGS. 1 to 9, and therefore, for a detailed description thereof, reference may be made to the description of the elastic member (520) of FIGS. 1 to 9.

[0128] In the battery module (30) according to the embodiment illustrated in FIG. 10, the elastic member (520) can be directly fixed to the housing (31). That is, unlike the description in FIGS. 1 to 9 above, the elastic member (520) can be fixed to the housing (31) while being interposed between the cell stack (100) and the housing (31). Accordingly, the frame portion (521) of the elastic member (520) is fixed to the housing (31), but the plurality of elastic ribs (522) extending from the frame portion (521) can be elastically deformed according to the expansion of the cell stack (100) and apply surface pressure to the cell stack (100). Meanwhile, the technical characteristics regarding the elastic force applied by the elastic ribs (522) of the elastic member (520) may refer to the description in FIGS. 1 to 9 above.

[0129] In order to evenly distribute the elastic force generated from the elastic member (520) to the cell laminate (100), one or more pressure plates (not shown) or compression pads (120) may be placed between the elastic member (520) and the cell laminate (100). For a detailed description of the pressure plate (not shown) and the compression pad (120), reference may be made to the descriptions of the pressure plate (530) and the compression pad (120) illustrated in FIGS. 1 to 9.

[0130] While various embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the technical spirit of the present invention as set forth in the claims. Furthermore, the embodiments described above may be implemented by deleting some components, and the embodiments may be implemented in combination with each other.

Claims

1. A cell stack in which multiple battery cells are stacked; An elastic member arranged on one side of the cell stack and configured to apply surface pressure to the cell stack in a direction parallel to the stacking direction of the plurality of battery cells; and A module housing in which the cell stack and the elastic member are accommodated, The above elastic member a frame portion supported by the above module housing; and A battery module including a plurality of elastic ribs extending from the frame portion in an inclined direction with respect to the stacking direction of the plurality of battery cells and configured to apply elastic force to the cell stack by elastically deforming as the cell stack expands.

2. In paragraph 1, At least one of the above plurality of elastic ribs A first pressurizing portion extending from the above frame portion; and Including a second pressurizing part connected to an end of the first pressurizing part, A battery module wherein the width of the second pressurizing portion is smaller than the width of the first pressurizing portion.

3. In paragraph 2, A battery module in which the plurality of elastic ribs in the elastic member are symmetrically arranged with respect to a central axis parallel to the longitudinal direction of the battery cell.

4. In paragraph 3, A battery module in which at least one of the first pressurizing portion or the second pressurizing portion has a width that gradually decreases as it approaches the central axis.

5. In paragraph 2, A battery module wherein the first pressurizing portion and the second pressurizing portion are made of different materials.

6. In paragraph 1, The above frame portion is provided in a frame-shaped structure having a pair of long-side frames and a pair of short-side frames, A battery module wherein the plurality of elastic ribs are connected to at least one of the pair of long edge edges.

7. In paragraph 1, A battery module further comprising a compression pad disposed between the plurality of battery cells and the elastic member.

8. A plurality of battery modules each including a plurality of battery cells; and It includes a pack housing that accommodates the plurality of battery modules, At least one battery module among the plurality of battery modules A cell stack in which the plurality of battery cells are stacked; A side plate disposed on one side of the cell stack and coupled to the pack housing; and It includes an elastic member disposed between the cell laminate and the side plate, The above elastic member a frame portion supported by the above side plates; and A battery pack including a plurality of elastic ribs extending from the frame portion in a direction inclined with respect to the stacking direction of the plurality of battery cells and configured to apply elastic force to the cell stack by elastically deforming as the cell stack expands.

9. In paragraph 8, At least one battery module above A battery pack further comprising a pressure plate interposed between the cell stack and the elastic member.

10. In paragraph 9, At least one battery module above A battery pack further comprising a connecting member connecting the pressure plate and the side plate.

11. In paragraph 9, At least one battery module above A battery pack further comprising a compression pad disposed between the pressure plate and the plurality of battery cells.

12. In paragraph 8, A battery pack in which the lower surface of the cell stack in the at least one battery module is exposed to the pack housing.

13. In paragraph 8, At least one elastic rib among the above plurality of elastic ribs A first pressurizing portion extending from the above frame portion; and Including a second pressurizing part connected to an end of the first pressurizing part, A battery pack wherein the width of the second pressurizing portion is smaller than the width of the first pressurizing portion.

14. In paragraph 8, The above frame portion is provided in a frame-shaped structure having a pair of long-side frames and a pair of short-side frames, A battery pack wherein the plurality of elastic ribs are connected to at least one of the pair of long edge edges.

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