Battery module, battery pack and vehicle comprising same

Abstract

The present invention provides a battery module, a battery pack, and a vehicle comprising same, in which tab disconnection issues caused by swelling of battery cells can be prevented. The battery module includes a cell assembly in which a plurality of battery cells having electrode leads are stacked. The cell assembly is characterized in that a plurality of bent portions, each bent while maintaining a predetermined radius, are formed in at least one of a plurality of electrode leads arranged along the stacking direction of the plurality of battery cells.

Description

Battery modules, battery packs, and automobiles including the same

[0001] The present invention relates to a battery module, a battery pack, and an automobile including the same, and more specifically, to a battery module, a battery pack, and an automobile including the same capable of preventing tap disconnection caused by swelling of a battery cell.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2024-0160260 filed on November 12, 2024, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0003] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product groups, are widely applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electric sources. These secondary batteries are attracting attention as a new energy source for enhancing eco-friendliness and energy efficiency, not only for the primary advantage of drastically reducing the use of fossil fuels but also because they generate no by-products from energy use.

[0004] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, or unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Additionally, depending on the charge / discharge capacity required for the battery pack, multiple secondary batteries are connected in parallel to form a battery pack. Accordingly, the number of secondary batteries included in the battery pack can be varied depending on the required output voltage or charge / discharge capacity.

[0005] Secondary batteries may be equipped with an electrode assembly in which positive and negative plates are alternately stacked. In this case, the positive and negative plates are separated by a separator. Electrode tabs are connected to these electrode plates according to their respective polarities. Electrode leads are welded to the stack of electrode tabs where they are gathered. To adapt to the high-capacity environments of such secondary batteries, techniques such as increasing the number and size of electrode tabs and leads have been applied. However, simply increasing the number and / or size of electrode tabs and leads alone makes it difficult to guarantee a stable and reliable connection between them. Furthermore, as the number and / or size of electrode tabs and leads increase, particularly in pouch-type secondary batteries, there is a problem where electrode tabs may break due to load during the welding process.

[0006] Meanwhile, since the starting position of the electrode tab stacking portion is very close to the electrode assembly, the welding positions of the electrode tab and electrode lead may also be very close to the electrode assembly. Consequently, the part of the electrode tab protruding from the electrode assembly is inclined at a steep angle and pulled taut, making it highly vulnerable to stress; as a result of the load applied to that part during welding, a problem arises where a wire breaks. Furthermore, in this structure, as the overall width of the cell assembly increases due to cell swelling of the secondary battery during use, significant tension is placed on the welded electrode lead portion. Consequently, the electrode tab portion, which is inclined at a steep angle and pulled taut, may break.

[0007] Solving the problem of electrode tab disconnection caused by cell swelling in secondary batteries is crucial for ensuring their stability and lifespan. Therefore, it is necessary to develop battery modules and battery packs with a structure that prevents electrode tab disconnection even when cell swelling occurs.

[0008] Accordingly, the technical problem to be solved by the present invention is to provide a battery module, a battery pack, and an automobile including the same, which are equipped with a structure capable of preventing tab disconnection caused by swelling of the battery cell.

[0009] In addition, the invention provides a battery module, a battery pack, and an automobile including the same, which are equipped with a structure capable of further securing the margin distance of the electrode leads.

[0010] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below.

[0011] To solve the above objective, the present invention comprises a cell assembly in which a plurality of battery cells having electrode leads are stacked, wherein the cell assembly has a plurality of bending portions formed on at least one of the plurality of electrode leads arranged along the stacking direction of the plurality of battery cells, each bending portion while maintaining a certain radius.

[0012] For example, the plurality of bending parts may be configured so that at least a portion of them are unfolded according to the swelling of the cell assembly.

[0013] For example, the plurality of bending parts can each be bent in both directions according to the stacking direction of the plurality of battery cells.

[0014] For example, the plurality of bending parts can be continuously bent together to form a curved shape as a whole.

[0015] For example, the plurality of bending portions may form an S-shape in a cross-section perpendicular to the extension plane of the electrode lead.

[0016] For example, the electrode lead having a plurality of bending portions formed thereon may include an electrode lead positioned at the outermost edge among the plurality of electrode leads.

[0017] For example, the average radius of a plurality of bending portions formed on the outermost electrode leads may be larger than the average radius of a plurality of bending portions formed on the electrode leads positioned between the outermost electrode leads among the plurality of electrode leads.

[0018] For example, the number of multiple bending portions formed on the outermost electrode leads may be greater than the average of the number of multiple bending portions formed on the electrode leads positioned between the outermost electrode leads among the multiple electrode leads.

[0019] For example, the length of the electrode lead positioned at the outermost edge among the plurality of electrode leads may be longer than the length of the remaining electrode leads positioned in between.

[0020] For example, the plurality of electrode leads may be arranged to have a symmetrical shape with respect to the center of the stacking direction of the plurality of battery cells.

[0021] For example, the plurality of bending parts can be bent by setting the radius of each bending part by calculating the difference between the length of the electrode lead including the curved distance of each bending part and the length of the electrode lead including the straight distance of each bending part.

[0022] For example, the battery module further includes a busbar assembly connected to at least one side of the cell assembly, and the busbar assembly may include a busbar frame provided along the stacking direction of the plurality of battery cells and at least one busbar disposed on the busbar frame and electrically connected to the electrode leads of the plurality of battery cells.

[0023] For example, the plurality of bending parts may be located in the space between the cell case of the battery cell and the bus bar.

[0024] For example, the electrode lead is drawn out to the outside of the busbar frame through the electrode lead slot of the busbar frame, and at least a portion of the plurality of bending parts may be located outside the electrode lead slot.

[0025] For example, the plurality of bending parts may be bent continuously from one another to form a curved shape, and among the plurality of bending parts, the bending part closer to the electrode tab of the battery cell may be bent toward the inside of the cell assembly, and among the plurality of bending parts, the bending part less adjacent to the electrode tab of the battery cell may be bent toward the outside of the cell assembly.

[0026] For example, it can be configured so that at least a portion of the plurality of bending parts is unfolded according to the swelling of the cell assembly, thereby preventing the disconnection of the electrode tab.

[0027] For example, each battery cell may include an electrode assembly configured such that a positive plate and a negative plate are interposed with a separator, a cell case that accommodates the electrode assembly in an internal space, and electrode tabs including a positive tab and a negative tab, respectively connected to the positive plate and the negative plate.

[0028] For example, the electrode lead may be extended protruding in at least one direction from the cell case and connected to the positive tab and the negative tab, respectively, and a plurality of bending portions may be formed on at least one electrode lead connected to the negative tab.

[0029] For example, at least one electrode lead connected to the positive tab may have a bending portion formed therein.

[0030] For example, a plurality of bending portions may be formed on at least one electrode lead connected to the positive tab and the negative tab.

[0031] In addition, the present invention provides a battery pack comprising at least one of the battery modules described above.

[0032] In addition, the present invention provides a vehicle equipped with at least one of the above-described battery packs.

[0033] A battery module, a battery pack, and an automobile including the same according to various embodiments of the present invention have the effect of preventing disconnection of the welded portions of the electrode tab and the electrode lead.

[0034] In addition, the battery module, battery pack, and vehicle including the same according to various embodiments have the effect of effectively securing the margin distance of the electrode leads.

[0035] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0036] FIG. 1 is a cross-sectional view schematically showing a battery module according to one embodiment of the present invention.

[0037] Figure 2 is an enlarged view of area A of Figure 1, and is a drawing for explaining the cell assembly of a battery module.

[0038] FIG. 3 is an enlarged view of area B of FIG. 2, and is a drawing for explaining a plurality of bending parts of a cell assembly.

[0039] Figure 4 is a schematic diagram showing a battery cell applied to a battery module according to Figure 1.

[0040] FIG. 5 is a cross-sectional view illustrating the internal structure of a battery cell according to FIG. 4.

[0041] FIG. 6 is a drawing for explaining a plurality of bending parts deformed by swelling of a cell assembly according to FIG. 2.

[0042] FIGS. 7 to 11 are schematic drawings illustrating embodiments of a plurality of bending portions of a cell assembly of a battery module according to FIG. 1.

[0043] FIG. 12 is a drawing for illustrating an exemplary apparatus for manufacturing the bending portion of the aforementioned embodiments.

[0044] FIG. 13 is a drawing for explaining a method of setting the radius of the bending portion of the embodiments described above.

[0045] FIG. 14 is a schematic diagram showing the connection structure of the cell assembly and the busbar assembly of the battery module according to FIG. 1.

[0046] FIGS. 15 and 16 are schematic drawings illustrating embodiments of electrode leads of a cell assembly of a battery module according to FIG. 1.

[0047] FIG. 17 is a schematic diagram showing a battery pack including battery modules of the embodiments described above.

[0048] FIG. 18 is a schematic drawing of a vehicle including a battery pack according to FIG. 17.

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0050] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0051] In addition, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar configurations are omitted, and the focus is on the differences.

[0052] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0053] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0054] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0055] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0056] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0057] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0058] Meanwhile, although terms indicating directions such as up, down, left, right, front, and back may be used in this specification, these terms are used merely for convenience of explanation and may vary depending on the position or arrangement, rotation, or position of the observer, as is obvious to those skilled in the art of this invention.

[0059] The present invention may be implemented in the following embodiments, each independently. Furthermore, the present invention may be implemented in combination of two or more of the following embodiments. Each of the following embodiments may not only be implemented independently but may also be freely combined with one another.

[0060]

[0061] First, with reference to FIGS. 1 to 3, the structure of a cell assembly (100) of a battery module (10) according to one embodiment of the present invention will be described.

[0062] FIG. 1 is a schematic cross-sectional view of a battery module (10) according to an embodiment of the present invention, FIG. 2 is a drawing for explaining a cell assembly (100) of the battery module (10) by enlarging area A of FIG. 1, and FIG. 3 is a drawing for explaining a plurality of bending parts (1131, 1132) of the cell assembly (100) by enlarging area B of FIG. 2.

[0063] Referring to FIGS. 1 to 3, a battery module (10) according to one embodiment of the present invention includes a cell assembly (100) in which a plurality of battery cells (110) having electrode leads (113) are stacked.

[0064] The battery module (10) may include a busbar assembly (200) electrically connected to the cell assembly (100). A detailed structure thereof will be described later with reference to FIG. 14.

[0065] Additionally, the battery module (10) may include a module case (300) capable of accommodating a cell stack (100) and a busbar assembly (200) inside. The module case (300) may be of any shape as long as it covers six sides of the cell stack (100) and the busbar assembly (200).

[0066] A plurality of battery cells (110) may be pouch-type battery cells, and the detailed structure will be described later with reference to FIGS. 5 and FIGS. Additionally, such pouch-type battery cells may be bidirectional withdrawal type battery cells in which a pair of electrode leads (113) having a first polarity and a second polarity are drawn out in opposite directions. A plurality of such pouch-type battery cells may be stacked facing each other to form a single cell assembly (100). At this time, the first polarity may be a positive electrode and the second polarity may be a negative electrode, or vice versa.

[0067] Additionally, the cell assembly (100) may be arranged such that the electrode lead (113) provided for each battery cell (110) extends along a direction perpendicular to the ground. That is, each battery cell (110) may be positioned upright so that its side rests on the ground.

[0068] In this way, each battery cell (110) includes an electrode lead (113), and these electrode leads (113) can be arranged along the stacking direction of the battery cell (110). This allows for efficient maintenance of electrical connections between individual battery cells (110) within the cell assembly (100).

[0069]

[0070] At least one of these multiple electrode leads (113) may include a plurality of bending portions (1131, 1132) that are bent to have a specific shape. These multiple bending portions (1131, 1132) provide flexibility to the electrode lead (113) and may be designed so that the electrode lead (113) is not damaged by physical stress caused by various external factors such as thermal expansion and mechanical deformation within the cell assembly (100).

[0071] Multiple bending portions (1131, 1132) may be formed at specific locations on the electrode lead (113), thereby providing the necessary flexibility and strength to the electrode lead (113). For example, the shape and location of the multiple bending portions (1131, 1132) can contribute to extending the fatigue life of the electrode lead (113) by optimizing the stress distribution. The shape of the multiple bending portions (1131, 1132) can be implemented in various forms, such as V-shapes, U-shapes, or arc shapes, thereby allowing the electrode lead (113) to be designed to withstand shocks or vibrations better.

[0072] A plurality of bending portions (1131, 1132) can each be designed to maintain a constant radius. That is, a plurality of bending portions (1131, 1132) can each be designed to have a constant curvature, thereby mitigating stress concentration that may occur due to a sudden change in curvature of the electrode lead (113). This can serve to maintain a balance of strength and flexibility of the electrode lead (113), and ensure that physical stress is evenly distributed even when the electrode lead (113) is subjected to external vibration or impact, thereby stably maintaining the performance of the battery module (10) in a long-term usage environment.

[0073] These multiple bending portions (1131, 1132) are formed to secure a margin distance between the electrode lead (113) and the connected components in the event of cell swelling. Cell swelling is a phenomenon in which additional stress is applied to the electrode lead (113) as the battery cell (110) expands due to an increase in internal pressure or a change in temperature. In order to sufficiently maintain the margin distance of the electrode lead (113) during such expansion, a bending structure can be applied to the electrode lead (113) to provide a predetermined margin length.

[0074] If one intends to secure the margin distance of the electrode lead (113) by using only one bending part without including multiple bending parts (1131, 1132), a problem may arise because the bending part takes up a large space by having a large radius in order to achieve the margin distance required for minimal stress relief with one bending part.

[0075] In other words, the radius of the bending section must be set large in order to provide a sufficient margin distance to accommodate swelling with a single bending section. As a result, an unnecessarily large placement space may be required around the electrode lead (113), which raises concerns about reduced space utilization within the battery module (10).

[0076] To avoid such problems, a battery module (10) according to one embodiment of the present invention may be configured to have a plurality of bending parts (1131, 1132) that are each bent while maintaining a certain radius (R). By having a plurality of bending parts (1131, 1132), the radius (R) required to secure the margin distance for each bending part (1131, 1132) can be designed to be relatively small. As a result, the plurality of bending parts (1131, 1132) occupy less space overall within the battery module (10), and consequently, the integration density of the battery cell (110) can be increased, thereby increasing space utilization.

[0077] In addition, by having a plurality of bending portions (1131, 1132), the electrode lead (113) can be provided with a structure that can more effectively distribute stress caused by cell swelling to each bending portion (1131, 1132). This structure allows the electrode lead (113) to respond more flexibly to excessive tensile force caused by cell swelling, thereby reducing fatigue damage to the electrode lead (113) and preventing disconnection of the connection portion with other components connected to the electrode lead (113).

[0078]

[0079] Next, with reference to FIGS. 4 and FIGS. 5, the specific structure of the battery cell (110) applied to the present invention will be described.

[0080] FIG. 4 is a schematic diagram showing a battery cell (110) applied to a battery module (10) according to FIG. 1, and FIG. 5 is a cross-sectional view for explaining the internal structure of the battery cell (110) according to FIG. 4. FIG. 5 shows an electrode lead (113) in a state where a plurality of bending parts (1131, 1132) are not provided.

[0081] Referring to FIGS. 4 and 5, the battery cell (110) includes an electrode assembly (111), an electrode tab (112), an electrode lead (113), and a cell case (114).

[0082] The electrode assembly (111) is formed by alternately stacking positive plates and negative plates, with the two separated by a separator. Each of these electrode plates may be connected such that an electrode tab (112) protrudes from the electrode assembly (111) according to its respective polarity.

[0083] The electrode lead (113) can be extended in a certain direction by being connected to each electrode tab (112) including a positive tab and a negative tab provided in the electrode assembly (111). In this case, the electrode lead (113) connected to the positive tab has a positive charge, and the electrode lead (113) connected to the negative tab has a negative charge. Each of these electrode leads (113) can be extended and drawn out to the outside of the cell case (114).

[0084] The cell case (114) may be made of a laminate sheet in which a resin layer, a metal layer, and a resin layer are sequentially laminated, and is sealed by heat fusion or the like after accommodating the electrode assembly (111). Before the cell case (114) is sealed by heat fusion or the like, an electrolyte, usually an electrolyte solution, is injected into the interior of the cell case (114) along with the electrode assembly (111). With the electrode assembly (111) and the electrolyte solution embedded inside the cell case (114), the outer surface of the cell case (114) is heat-fused to seal the interior of the cell case (114). At this time, the cell case (114) is structured such that a portion of the laminate sheet is indented to accommodate the electrode assembly (111), and the metal layer may be made of aluminum.

[0085] The electrode tab (112) is a component that connects the electrode assembly (111) and the electrode lead (113) to allow current to flow. This electrode tab (112) can be protruded from the electrode assembly (111), pulled at a certain angle, gathered, and then compressed to be welded to the electrode lead (113). At this time, the connection point between the electrode tab (112) and the electrode lead (113) of the battery cell (110), i.e., the welded area, can react sensitively to the expansion of the battery cell (110), i.e., cell swelling. As the battery cell (110) repeatedly charges and discharges, if gas is generated inside the battery cell (110) or if expansion occurs due to a rise in temperature, a large stress is consequently applied to the welded area. In particular, cracks may occur in the welded area due to metal fatigue, or the electrode tab (112) or the electrode lead (113) may gradually deform, leading to a break in the welded area. In the present invention, to prevent such disconnection, it is proposed to provide a plurality of bending parts (1131, 1132) on the electrode lead (113).

[0086]

[0087] Hereinafter, with reference to FIG. 6, the deformation process of a plurality of bending parts (1131, 1132) according to an embodiment of the present invention for preventing a broken wire at a welded part will be described.

[0088] FIG. 6 is a drawing for explaining a plurality of bending parts (1131, 1132) deformed by swelling of the cell assembly (100) according to FIG. 2.

[0089] Referring to the description of FIGS. 4 and 5 and FIG. 6, the plurality of bending parts (1131, 1132) can be configured so that at least a portion of them are unfolded according to the swelling of the cell assembly (100).

[0090] When cell swelling occurs, at least one battery cell (110) expands, and the overall width of the cell assembly (100) may increase. As a result, at least some of the plurality of electrode leads (113) arranged along the stacking direction of the cell assembly (100) may be displaced in the expansion direction in which the overall width of the cell assembly (100) increases due to the expansion of the battery cell (110) caused by cell swelling. Depending on the amount of displacement of the battery cell (110), excessive tensile force may be applied to the electrode leads (113).

[0091] At this time, the electrode lead (113) of the cell assembly (100) according to the present embodiment has a plurality of bending portions (1131, 1132), thereby securing an electrode lead margin that can effectively respond to cell swelling. Each bending portion (1131, 1132) undergoes deformation such as naturally straightening, thereby dispersing the stress applied to the electrode lead (113) and reducing the risk of disconnection or fatigue damage.

[0092] Thus, when gas is generated inside a battery cell (110) within a cell assembly (100) due to causes such as overcharging, overheating, or external impact, and a cell swelling phenomenon occurs in which the battery cell (110) expands, the mechanical stress applied to the electrode lead (113) can be effectively relieved.

[0093]

[0094] FIGS. 7 to 11 are schematic drawings illustrating embodiments of a plurality of bending portions (1131, 1132, 1133) of a cell assembly (100) of a battery module (10) according to FIG. 1.

[0095] Referring to FIGS. 7 to 11, a cell assembly (100) of a battery module (10) according to one embodiment of the present invention may have at least one electrode lead (113) formed with a plurality of bending portions (1131, 1132, 1133) having various shapes or bending directions.

[0096] These multiple bending parts (1131, 1132, 1133) can be configured at different positions of the electrode lead (113) with various angles and shapes, and can be designed to effectively respond to various stress conditions or space utilization, such as expansion of the battery cell (110), external impact, and vibration.

[0097] At least one electrode lead (113) can be bent multiple times at different locations according to the stacking direction of multiple battery cells. At this time, as the number of bendings increases, the radius per bending part (1131, 1132) may decrease.

[0098] For example, if the radius of a single bending section formed on an electrode lead (113) required to secure a margin distance is about 2 mm, then if two bending sections (1131, 1132) are formed, they can each be designed to have a radius of about 1 mm from the extended surface of the electrode lead (113). That is, when two bending sections (1131, 1132) with a radius of about 1 mm are formed, compared to when a single bending section with a radius of about 2 mm is formed, the space occupied within the battery module (10) in the stacking direction of multiple battery cells (110) is reduced, so the space utilization can be relatively high. In addition, by providing two bending sections (1131, 1132) having a radius of about 1 mm, the tensile force applied to the electrode lead (113) is effectively distributed to each bending section (1131, 1132) compared to the case where a single bending section having a radius of about 2 mm is formed, thereby effectively responding to swelling of the battery cell (110) and external impact.

[0099] In one embodiment, a plurality of bending portions (1131, 1132, 1133) can each be bent in at least one direction according to the stacking direction of a plurality of battery cells (110). That is, the plurality of bending portions (1131, 1132) can each be bent at least once in the same or different direction to effectively distribute the mechanical stress of the electrode lead (113).

[0100] A plurality of bending sections (1131, 1132, 1133) can be continuously bent from one another to form a curved shape as a whole. This continuous bending can allow the electrode lead (113) to be designed and deformed more flexibly. That is, the plurality of bending sections (1131, 1132, 1133) can each have a certain radius and can be designed to form at least an S-shape in a cross-section perpendicular to the extension plane of the electrode lead (113). For example, as shown in FIG. 7, a bending section (1131) bent to have a radius R in one direction and a bending section (1132) bent to have a radius R in the opposite direction can be continuously formed from one another to form a curved shape as a whole. Additionally, as illustrated in FIG. 10, a bending section (1131) bent to have a radius R in one direction, a bending section (1132) bent to have a radius R in the opposite direction, and a bending section (1131) bent to have a radius R in the opposite direction may be formed continuously to have a curved shape as a whole. Of course, although not illustrated, it is also possible to continuously form a bending section (1131) bent to have a radius R in one direction and a bending section (1131) bent to have a radius R in the same direction.

[0101] Additionally, a plurality of bending sections (1131, 1132, 1133) may be configured to be spaced apart from each other by a predetermined distance. This optimizes stress transfer between the bending sections (1131, 1132, 1133), thereby simultaneously increasing the mechanical strength and flexibility of the electrode lead (113). As a result, each bending section (1131, 1132, 1133) can act independently of each other and evenly distribute the stress applied to the electrode lead (113). For example, as shown in FIG. 8, a bending section (1131) bent to have a radius R in one direction may be formed, and then a bending section (1132) bent to have a radius R in the opposite direction may be formed at a position spaced apart by a predetermined distance so that they deform independently of each other. Additionally, as shown in FIG. 9, a bending part (1131) bent to have a radius R in one direction is formed, and then a bending part (1131) bent to have a radius R in the same direction is formed at a position spaced apart by a predetermined distance so that they can be configured to deform independently of each other.

[0102] Additionally, a plurality of bending sections (1131, 1132, 1133) may be configured to have the same radius to secure mutually equal margin distances. Additionally, if necessary, they may be configured to have different radii to secure different margin distances. For example, as shown in FIG. 11, a bending section (1131) bent to have a radius R in one direction may be formed, and then a bending section (1133) bent to have a radius R' in the opposite direction may be formed at a position spaced apart by a predetermined distance (e.g., R > R'), but this is not limited to the illustrated example. A plurality of bending sections (1131, 1132, 1133) having the same radius can enable uniform stress distribution across the electrode lead (113), thereby allowing for more effective management of stress generated during cell swelling. On the other hand, multiple bending sections (1131, 1132, 1133) having different radii can be designed to meet specific requirements and can effectively respond to more complex mechanical environments by securing different margin distances for each.

[0103] Thus, optimal performance can be maintained by adjusting the radius of each bending part (1131, 1132, 1133) in consideration of space constraints or loads in specific parts within the battery module (10).

[0104]

[0105] Referring again to FIGS. 1 to 3, we examine embodiments of a plurality of bending parts (1131, 1132, 1133) according to the position of a plurality of electrode leads (113) in the battery module (10).

[0106] First, the electrode lead (113) positioned at the outermost edge among the plurality of electrode leads (113) may be designed to have a longer length than the other electrode leads (113) located in between. The plurality of electrode leads (113) may be provided such that their lengths gradually increase from the center of the cell assembly (100) toward the outermost edge along the stacking direction of the plurality of battery cells (110). This is because, when cell swelling occurs, the electrode lead (113) located at the outermost edge may undergo the greatest positional change and is therefore likely to receive the greatest mechanical stress and deformation.

[0107] A plurality of electrode leads (113) can be arranged to have a symmetrical shape as a whole with respect to the center of the stacking direction of the plurality of battery cells (110). By doing so, different stresses applied to each of the plurality of electrode leads (113) are efficiently reduced, thereby reducing the risk of damage or disconnection that may occur at the joint between the electrode tab (112), the electrode lead (113), and the bus bar (220).

[0108] Among the plurality of electrode leads (113), the electrode lead (113) having a plurality of bending portions (1131, 1132) formed thereon may include at least one electrode lead (113) positioned at the outermost edge among the plurality of electrode leads (113).

[0109] In other words, at least one electrode lead (113) positioned at the outermost of the plurality of electrode leads (113) may be provided with a plurality of bending portions (1131, 1132). The plurality of bending portions (1131, 1132) can be bent so that when cell swelling occurs, the electrode lead (113) located at the outermost position undergoes the greatest positional change, thereby securing a sufficient electrode lead margin of the electrode lead (113) within the battery module (10) and allowing it to be positioned without interference problems such as entanglement or twisting between adjacent electrode leads (113).

[0110] Thus, the bending portion of the electrode lead (113), which is most severely deformed due to the expansion of the battery cell (110) caused by cell swelling, is at least partially straightened, thereby effectively minimizing the cell swelling force applied to the electrode lead (113). As a result, the risk of the electrode lead (113) detaching from the busbar (220), which will be described later, or the connection portion between the electrode lead (113) and the electrode tab (112) being short-circuited during cell swelling can be effectively prevented.

[0111] Multiple bending portions (1131, 1132) may be formed not only on the electrode lead (113) positioned at the outermost edge, but also on the electrode lead (113) positioned between them. At this time, the average radius (R) of the multiple bending portions (1131, 1132) formed on at least one electrode lead (113) positioned at the outermost edge may be larger than the average radius (R) of the multiple bending portions (1131, 1132) formed on the electrode lead (113) positioned between the electrode lead (113) positioned at the outermost edge among the multiple electrode leads (113). This is to ensure a minimum margin distance required as the electrode lead (113) located at the outermost edge may be subjected to the greatest tensile force.

[0112] In addition, for the same reason, the number of bending portions (1131, 1132) formed on the outermost electrode lead (113) can be configured to be greater than the average of the number of bending portions (1131, 1132) formed on the electrode lead (113) positioned between the outermost electrode lead (113) among the electrode lead (113).

[0113] Thus, the battery module (10) according to one embodiment of the present invention can effectively improve the durability of the overall battery module (10) by increasing the margin distance of the electrode lead (113) placed at the outermost edge where positional misalignment due to pressure deformation during cell swelling may occur most severely.

[0114]

[0115] Hereinafter, with reference to FIGS. 12 and 13, a method for forming a plurality of bending parts (1131, 1132) according to an embodiment of the present invention will be described.

[0116] FIG. 12 is a drawing for explaining an exemplary apparatus for manufacturing a plurality of bending parts (1131, 1132) of the aforementioned embodiments, and FIG. 13 is a drawing for explaining a method for setting the radius of a plurality of bending parts (1131, 1132) of the aforementioned embodiments.

[0117] Referring to FIG. 12, a plurality of bending parts (1131, 1132) can be formed by a pressure jig (50). At this time, the pressure jig (50) is designed with a convex part (51) and a concave part (52) so that the electrode lead (113) can be pressed to have a desired shape. For example, the pressure jig (50) may have a shape corresponding to a plurality of bending parts (1131, 1132) having a certain radius (R). In addition, by having a shape corresponding to a single bending part having a certain radius (R), the plurality of bending parts (1131, 1132) may each have various radii or positions.

[0118] At this time, before placing the electrode lead (113) on the pressure jig (50), the electrode lead (113) can be fixed by applying pressure in advance with a pre-press jig (60). The pre-press jig (60) helps to stably maintain the initial shape of the electrode lead (113), thereby allowing the molding operation on the pressure jig (50) to be performed more precisely. This two-step pressure process can improve the quality of the bending of the electrode lead (113).

[0119] In addition, the combined use of the pressure jig (50) and the free pressure jig (60) can accurately adjust the position and angle of the electrode lead (113), thereby effectively securing the required curvature and margin distance for the multiple bending parts (1131, 1132).

[0120] In addition, the design of the convex portion (51) and concave portion (52) of the pressure jig (50) can improve the formability of the electrode lead (113) and effectively disperse and reduce the tensile force applied to the electrode lead (113). The convex portion (51) and concave portion (52) can be designed to uniformly control the curvature and thickness of the electrode lead (113), thereby minimizing the mechanical stress received by the electrode lead (113) during the forming process and, in particular, preventing stress concentration caused by the complex shape. This suppresses cracks and fatigue damage of the electrode lead (113) and increases the deformation resistance of the electrode lead (113), thereby further strengthening the durability of the battery module (10). However, the forming method of the plurality of bending portions (1131, 1132) described above is not limited to the above, and various other design methods that can improve the formability and durability of the electrode lead (113) may be used.

[0121] Referring to FIG. 13, a plurality of bending sections (1131, 1132) according to one embodiment of the present invention can be designed by calculating the length (d2) of the electrode lead (113) by summing the curved distances of each bending section and the length (d1) of the electrode lead (113) by summing the straight distances of each bending section.

[0122] A plurality of bending sections (1131, 1132) may be formed in a structure that is mutually continuous or spaced apart at a certain interval, and are arranged along the length direction of each electrode lead (113). Each bending section (1131, 1132) can measure a curved distance and a straight distance based on the starting point and ending point of bending on the electrode lead (113), respectively. Through this structural configuration, the difference between the length (d2) including each curved distance and the length (d1) including each straight distance of the total length of the electrode lead (113) can be calculated. This allows for securing a sufficient margin distance to prevent tap disconnection when cell swelling occurs.

[0123] As a result, the radius (R) of each bending section (1131, 1132) can be set to have a minimum margin distance that effectively disperses mechanical stress generated during cell swelling on the electrode lead (113). This allows stress concentration to be relieved by maintaining a minimum radius of each bending section (1131, 1132) while preventing unnecessary space occupation and excessive process consumption. This design approach can ensure optimal structural stability that responds to deformation requirements within the electrode lead (113), prevents breakage of the electrode lead (113) when internal cell pressure rises, and further contributes to improving the reliability and long-term lifespan of the battery module.

[0124]

[0125] FIG. 14 is a schematic diagram showing the connection structure of the cell assembly (100) and the busbar assembly (200) of the battery module (10) according to FIG. 1.

[0126] Referring to FIG. 14, the battery module (10) may further include a busbar assembly (200) connected to at least one side of the cell assembly (100).

[0127] The busbar frame assembly (200) is coupled to at least one side of the cell assembly (100) and may include a busbar frame (210) and at least one busbar (220) installed on the busbar frame (210). Here, the busbar (220) is made of a metal material, such as copper, silver, tin, or plated copper, which has electrical conductivity, so that current can be safely carried. The electrode leads (113) can be in close contact with and welded to the busbar (220) to conduct electricity to each other. In addition, the busbar frame (210) may be made of an insulating material to provide electrical insulation.

[0128] A busbar frame (210) may be provided by being positioned on at least one side of a cell assembly (100) and may have a plurality of electrode lead slots (211) for allowing electrode leads (113) provided in a battery cell (110) to be drawn out to the outside of the busbar frame (210). A plurality of battery cells (110) may, for example, form a group of a plurality of them, and electrode leads (113) provided in a plurality of battery cells (110) belonging to the same group may be drawn out to the outside of the busbar frame (210) through the same electrode lead slot (211). Additionally, electrode leads (113) drawn out to the outside through the same electrode lead drawing slot (211) may be attached to the same busbar (220) by welding or the like.

[0129] In one embodiment, when the electrode leads (113) of the battery cell (110) are drawn out in both directions, the busbar frame assembly (200) may be coupled to each side of the cell assembly (100). The electrode leads (113) provided in each of the adjacent battery cells (110) may be drawn out through a single electrode lead slot (211) and coupled to the same busbar (220). In this case, the electrode leads (113) belonging to the same group may have the same polarity. For example, they may have a first polarity, which is a positive polarity. Of course, the number and polarity of the electrode leads (113) drawn out through a single electrode lead slot (211) may differ from the example given here depending on the serial and parallel connection relationship of the plurality of battery cells (110) within the cell assembly (100).

[0130] In the battery module (10) according to the present invention, at least some of the plurality of bending parts (1131, 1132) may be located outside the electrode lead slot (211) in consideration of space efficiency and prevention of interference with other components. This positioning can contribute to optimizing the spatial arrangement of the electrode lead (113) within the battery module (10), thereby maximizing the overall space efficiency of the battery module (10) and minimizing physical interference with surrounding components.

[0131] For example, among the plurality of bending parts (1131, 1132), the bending part (1132) that is closer to the electrode tab (112) of the battery cell (110) can be bent toward the inside of the cell assembly (100). On the other hand, the bending part (1131) that is less close to the electrode tab (112) can be bent toward the outside of the cell assembly (100). Of course, the opposite may also be true. In this way, interference is prevented by preventing the electrode leads (113) from coming into contact with each other through the change of direction between the plurality of bending parts (1131, 1132). In addition, physical interference with other electrical components, etc., can be prevented depending on the position of the electrode leads (113), thereby increasing the space utilization of the battery module (10).

[0132]

[0133] FIGS. 15 and FIGS. 16 are schematic drawings illustrating other embodiments of the battery module (10) according to FIG. 1.

[0134] As previously shown in FIGS. 4 and 5, a pair of electrode leads (113) extend outward in at least one direction from the cell case (114) of the battery cell (110) and can be connected to a positive tab and a negative tab, respectively.

[0135] At this time, a plurality of bending portions (1131, 1132) may be formed on at least one electrode lead (113b) connected to at least the negative tab. In a lithium-ion battery, the negative plate plays a major role in storing lithium ions, and when cell swelling occurs, the material transfer and volume expansion of the negative plate may appear relatively larger compared to the positive plate. Due to this cell swelling phenomenon, there is a possibility that a high tensile force may be applied to the electrode lead (113b) connected to the negative tab among the plurality of electrode leads (113).

[0136] In particular, due to the material difference between the positive lead (113a) and the negative lead (113b), the negative lead (113b) may be subjected to greater stress during swelling. For example, the negative lead (113b) is generally composed of a copper (Cu)-based material that is more flexible than aluminum (Al), and due to this characteristic, it must accommodate greater deformation during cell swelling, so it may be more sensitive to mechanical stress. Although copper has high electrical conductivity, it has a lower coefficient of thermal expansion compared to aluminum, so stress can easily concentrate when subjected to high stress.

[0137] Additionally, the negative lead (113b) may be designed to be relatively thin, which causes tensile force and bending stress to accumulate more easily during cell swelling. This thin structure can affect structural stability when the internal pressure of the battery cell (110) increases, and consequently, the negative lead (113b) may be damaged more easily than the positive lead (113a). On the other hand, the positive lead (113a) is usually composed of a material such as aluminum, which is lightweight and has high strength, so it may have relatively greater resistance to tensile deformation due to cell swelling.

[0138] Therefore, due to the material characteristics and structural design differences mentioned above, the negative lead (113b) is likely to receive higher mechanical stress when cell swelling occurs, and accordingly, the negative lead (113b), which can receive relatively higher stress, is provided with a plurality of bending parts (1131, 1132) to effectively control the overall stress.

[0139] At this time, a bending part (1134) with a larger radius may be provided to secure a minimum sufficient margin distance on at least one electrode lead (113a) connected to the positive tab. Of course, multiple bending parts (1131, 1132) may also be provided on at least one electrode lead (113a) connected to the positive tab to increase the space utilization within the overall battery module (10).

[0140]

[0141] FIG. 17 is a schematic diagram showing a battery pack (P) according to one embodiment of the present invention, and FIG. 18 is a schematic diagram showing a vehicle (V) according to one embodiment of the present invention.

[0142] Referring to FIG. 17, a battery pack (P) according to one embodiment of the present invention may include at least one battery module (10) according to a prior embodiment and a pack case (C) that accommodates the same.

[0143] A battery pack (P) according to one embodiment of the present invention may further include various other components of a battery pack (P) known at the time of filing the present invention. For example, a battery pack (P) according to one embodiment of the present invention may further include components such as a current sensor, a fuse, and a service plug.

[0144] Referring to FIG. 18, a vehicle (V) according to one embodiment of the present invention may include one or more battery packs (P) according to the present invention. In addition, a vehicle (V) according to one embodiment of the present invention may include various other components included in the vehicle in addition to the battery packs (P). For example, a vehicle (V) according to one embodiment of the present invention may include, in addition to the battery packs (P) according to one embodiment of the present invention, a vehicle body, a motor, an electronic control unit (ECU), or other control devices.

[0145] In addition, it is obvious that the battery pack (P) according to one embodiment of the present invention may also be provided in other devices, mechanisms, and facilities, such as an energy storage system using a secondary battery, in addition to the vehicle (V).

[0146] According to the various embodiments described above, a battery module (10) capable of preventing tap disconnection during cell swelling, a battery pack (P) including the same, and a vehicle (V) can be provided.

[0147]

[0148] As described above, although the present invention has been explained by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0149]

[0150] [Explanation of the symbol]

[0151] 10: Battery module

[0152] 100: Cell Assembly

[0153] 110: Battery cell

[0154] 111: Electrode assembly

[0155] 112: Electrode tab

[0156] 113: Electrode lead

[0157] 113a: Positive lead

[0158] 113b: Cathode lead

[0159] 1131, 1132, 1133, 1134: Bending section

[0160] 114: Cell Case

[0161] 200: Busbar Assembly

[0162] 210: Busbar Frame

[0163] 211: Electrode lead slot

[0164] 220: Busbar

[0165] 300: Modular Case

[0166] 50: Pressure jig

[0167] 51: Convex part

[0168] 52 Concave part

[0169] 60: Free pressure jig

[0170] P: Battery pack

[0171] C: Pack case

[0172] V: Car

[0173] R, R': Radius

Claims

1. A cell assembly comprising a plurality of battery cells stacked with electrode leads, and The above cell assembly is, A battery module characterized by having a plurality of bending portions formed on at least one of a plurality of electrode leads arranged along the stacking direction of the plurality of battery cells, each bending portion while maintaining a certain radius.

2. In Paragraph 1, The above plurality of bending parts are, A battery module characterized by being configured such that at least a portion is expanded according to the swelling of the cell assembly.

3. In Paragraph 1, The above plurality of bending parts are, A battery module characterized by being bent in both directions according to the stacking direction of the plurality of battery cells.

4. In Paragraph 3, The above plurality of bending parts are, A battery module characterized by being mutually and continuously bent to have a curved shape as a whole.

5. In Paragraph 1, The above plurality of bending parts are, A battery module characterized by forming an S-shape in a cross-section perpendicular to the extension plane of the electrode lead.

6. In Paragraph 1, The above plurality of bending parts are, A battery module characterized by being bent by calculating the difference between the length of the electrode lead including the curved distance of each bending part and the length of the electrode lead including the straight distance of each bending part to set the radius of each bending part.

7. In Paragraph 1, The electrode lead having the plurality of bending portions formed above is, A battery module characterized by including an electrode lead positioned at the outermost edge among the plurality of electrode leads.

8. In Paragraph 7, The average radius of the plurality of bending portions formed on the electrode leads disposed at the outermost edge is, A battery module characterized by having a radius larger than the average radius of a plurality of bending portions formed on electrode leads disposed between the outermost electrode leads among the plurality of electrode leads.

9. In Paragraph 7, The number of multiple bending portions formed on the electrode leads disposed at the outermost edge is, A battery module characterized by having more than the average of the number of bending portions formed on electrode leads positioned between the outermost electrode leads among the plurality of electrode leads.

10. In Paragraph 1, The length of the electrode lead positioned at the outermost among the plurality of electrode leads mentioned above is, A battery module characterized by being longer than the length of the remaining electrode leads placed in between.

11. In Paragraph 1, The above plurality of electrode leads are, A battery module characterized by being arranged to have a symmetrical shape with respect to the center of the stacking direction of the plurality of battery cells.

12. In Paragraph 1, The above cell assembly further includes a busbar assembly connected to at least one side, The above busbar assembly is, A busbar frame provided along the stacking direction of the plurality of battery cells; and It includes at least one busbar disposed on the busbar frame and electrically connected to the electrode leads of the plurality of battery cells, The above plurality of bending parts are, A battery module characterized by being located in the space between the cell case of the battery cell and the busbar.

13. In Paragraph 1, The above cell assembly further includes a busbar assembly connected to at least one side, The above busbar assembly is, It includes a busbar frame provided along the stacking direction of the plurality of battery cells, and The above electrode lead is drawn out to the outside of the busbar frame through the electrode lead slot of the busbar frame, and A battery module characterized in that at least some of the plurality of bending portions are located outside the electrode lead slot.

14. In Paragraph 13, The above plurality of bending parts are, A battery module characterized by having a curved shape formed by mutually continuous bending, wherein among the plurality of bending parts, the bending part closer to the electrode tab of the battery cell is bent toward the inside of the cell assembly, and among the plurality of bending parts, the bending part less adjacent to the electrode tab of the battery cell is bent toward the outside of the cell assembly.

15. In Paragraph 14, A battery module characterized by being configured such that at least a portion of the plurality of bending parts is straightened out according to the swelling of the cell assembly, thereby preventing the electrode tab from being disconnected.

16. In Paragraph 1, Each battery cell is, An electrode assembly configured such that a positive electrode plate and a negative electrode plate have a separator interposed between them; A cell case that accommodates the above electrode assembly in an internal space; and The electrode tab includes an anode tab and a cathode tab, each connected to the anode plate and the cathode plate, respectively. The above electrode lead is, It is extended protruding in at least one direction from the cell case and connected to the positive tab and the negative tab, respectively, and Multiple bending parts, A battery module characterized by being formed on at least one electrode lead connected to the above-mentioned negative electrode tab.

17. In Paragraph 16, A battery module characterized by having a bending portion formed on at least one electrode lead connected to the positive tab.

18. In Paragraph 16, Multiple bending parts, A battery module characterized by being formed on at least one electrode lead connected to the positive tab and the negative tab.

19. A battery pack comprising a battery module according to any one of claims 1 to 18.

20. A vehicle equipped with at least one battery pack according to claim 19

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