Battery cell, battery pack, and motor vehicle including same

Abstract

A battery cell according to an embodiment of the present invention includes an electrode assembly including a first electrode, a second electrode, and a separation membrane interposed therebetween, a battery housing that houses the electrode assembly from an opening formed on one side, a vent portion that covers the opening and is configured to break when the internal pressure of the battery housing increases to a certain level or more, and a deformation induction portion that is separated from the vent portion by a predetermined distance in the radial direction and is provided inside the vent portion in the radial direction, and a housing cover including the same.

Description

Technical Field

[0001] The present invention relates to a battery cell, a battery pack, and an automobile including the same.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0183384 filed on December 23, 2022, and Korean Patent Application No. 10-2023-0064622 filed on May 18, 2023, and all of the contents disclosed in the specifications and drawings of the applications are incorporated herein.

Background Art

[0003] Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by an electric drive source. Such secondary batteries are attracting attention as a new energy source not only because of the primary advantage of significantly reducing the use of fossil fuels but also because they are environmentally friendly and can improve energy efficiency in that no by-products are generated during energy use.

[0004] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, and the like. The operating voltage of such a unit secondary battery cell, i.e., a unit battery cell, is about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a plurality of battery cells are connected in series to form a battery pack. Also, a battery pack can be configured by connecting a plurality of battery cells in parallel according to the charge and discharge capacity required for the battery pack. Therefore, the number of battery cells included in the battery pack can be variously set according to the required output voltage and / or charge and discharge capacity.

[0005] In the BDCR (Beading / Crimping) structure of a cylindrical battery cell, the vent portion plays a role in preventing fire by reducing the internal pressure of the battery cell due to gas through the destruction of notches provided in the vent portion during the process of increasing the internal pressure of the battery cell.

[0006] However, when the internal pressure of the battery cell increases, warping of the housing cover occurs, resulting in a gap between the housing cover and the gasket surrounding the housing cover. As a result, slippage of the housing cover occurs, and there is a risk of leakage of the electrolyte inside the battery cell.

[0007] However, when reducing the thickness of the notch to adjust the venting timing, there are problems in that there are risks to processability and product safety.

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to minimize the deformation of the shape of the housing cover by further providing a deformation induction portion in addition to the vent portion and preferentially inducing the deformation of the deformation induction portion.

[0009] Another object of the present invention is to suppress the warping of the flat portion of the housing cover by applying the deformation induction portion and ensure the flatness of the housing cover.

[0010] More specifically, an object of the present invention is to suppress the leakage of the electrolyte due to the slippage of the housing cover by preventing the generation of a gap between the housing cover and the gasket surrounding the housing cover.

[0011] Another object of the present invention is to adjust the timing at which the destruction of the vent portion occurs by applying the deformation induction portion.

[0012] However, the technical problems to be solved by the present invention are not limited to the foregoing problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

Means for Solving the Problems

[0013] A battery cell according to an embodiment of the present invention for achieving the above problems includes an electrode assembly including a first electrode, a second electrode, and a separation membrane interposed therebetween, a battery housing for housing the electrode assembly from an opening formed on one side, a vent portion configured to cover the opening and break when the internal pressure of the battery housing increases to a certain level or more, and a deformation induction portion separated from the vent portion by a predetermined distance in the radial direction and provided inside the vent portion in the radial direction, and a housing cover including the same.

[0014] In one aspect of the present invention, the deformation induction portion may be configured to induce preferential deformation of the housing cover in a region where the deformation induction portion is formed when the internal pressure of the battery housing increases to a certain level or more.

[0015] In another aspect of the present invention, the deformation induction portion may be configured to form a circular closed loop.

[0016] In still another aspect of the present invention, the vent portion and the deformation induction portion are provided in a flat portion that is a flat central region of the housing cover.

[0017] Desirably, the deformation induction portion may be provided inside the vent portion in the radial direction.

[0018] In still another aspect of the present invention, the deformation induction portion may be provided in a region between the center point of the cover and a point that is 70% of the radius of the housing cover.

[0019] Desirably, it may be provided in a region between a point that is 20% of the radius of the housing cover and a point that is 60% of the radius of the housing cover.

[0020] On another aspect of the present invention, the length in the radial direction between the deformation induction portion and the vent portion may be 10 to 50% of the length in the radial direction of the housing cover.

[0021] On another aspect of the present invention, the deformation induction portion may include at least one of an upper deformation induction portion provided on the upper surface of the housing cover and a lower deformation induction portion provided on the lower surface of the housing cover.

[0022] Desirably, the deformation induction portion may include an upper deformation induction portion provided on the upper surface of the housing cover and a lower deformation induction portion provided on the lower surface of the housing cover.

[0023] On another aspect of the present invention, the thickness of the housing cover in the region where the deformation induction portion is formed may be configured to be larger than the thickness of the housing cover in the region where the vent portion is formed.

[0024] On another aspect of the present invention, the upper deformation induction portion and the lower deformation induction portion may be provided offset from each other.

[0025] In addition, the present invention provides a battery pack including at least one battery cell according to the above-described embodiment as a battery pack.

[0026] Further, the present invention provides an automobile including at least one battery pack according to the above-described embodiment as an automobile.

Advantages of the Invention

[0027] According to the present invention, in addition to the vent portion, a deformation induction portion is further provided to induce the deformation of the deformation induction portion, so that the deformation of the shape of the housing cover can be minimized.

[0028] Further, according to the present invention, by applying a deformation-inducing portion to suppress the warping of the flat portion of the housing cover, the flatness of the housing cover can be ensured.

[0029] More specifically, according to the present invention, by preventing the generation of a gap between the housing cover and the gasket surrounding the housing cover, the leakage of the electrolytic solution due to the slippage of the housing cover can be suppressed.

[0030] Furthermore, according to the present invention, by applying a deformation-inducing portion, the time point at which the vent portion is broken can be adjusted.

[0031] However, the effects of the present invention are not limited to the effects described above, and other technical effects of the present invention not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

[0032] The following drawings attached to this specification illustrate the preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

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Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Mode for Carrying Out the Invention

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in this specification and the claims are not to be construed as limited to ordinary or dictionary meanings. The inventor himself interprets them according to the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that he can appropriately define the concept of the terms in order to explain the invention in the best way. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, there may be various equivalents and modifications that can replace them at the time of this application.

[0035] Also, for the purpose of assisting in the understanding of the invention, the attached drawings may show some components exaggerated rather than at actual scale. Note that the same reference numerals may be assigned to the same components in different embodiments.

[0036] The fact that two comparison targets are the same means that they are "substantially the same". Therefore, "substantially the same" may include cases where there are deviations regarded as a low level in the industry, for example, deviations within 5%. Also, the fact that any parameter is uniform in a given region may mean that it is uniform from an average perspective.

[0037] Terms such as first, second, etc. are used to describe various components, but the components are not limited by these terms. These terms are only used to distinguish one component from another, and unless otherwise specified, the first component may be the second component.

[0038] Throughout the specification, unless otherwise specified, each component may be singular or plural.

[0039] The statement that any configuration is arranged "above (or below)" a component or "on (or under)" a component means that not only can any configuration be directly arranged on the upper surface (or lower surface) of the said component, but it may also mean that there may be additional other configurations intervening between the said component and any configuration arranged above (or below) the said component.

[0040] Also, when it is described that a certain component is "connected", "coupled" or "joined" to another component, it should be understood that the said components may be directly connected or joined to each other, but there may also be other components "intervening" between the respective components, or each component may be "connected", "coupled" or "joined" by another component.

[0041] Throughout the specification, unless otherwise specified, the description of "A and / or B" means "A", "B", or "A and B", and the description of "from C to D" means greater than or equal to C and less than or equal to D unless otherwise specified.

[0042] For the sake of convenience of explanation, in this specification, the direction along the longitudinal direction of the winding shaft of the electrode assembly 10 wound in a jelly roll form is defined as the axial direction (Y direction). And the direction surrounding the said winding shaft is defined as the circumferential direction or the peripheral direction (X direction). And the direction from approaching the winding shaft to moving away from the winding shaft is defined as the radial direction. Among these, in particular, the direction approaching the winding shaft is defined as the centripetal direction, and the direction moving away from the winding shaft is defined as the centrifugal direction.

[0043] FIG. 1 is a diagram for explaining a battery cell 1 according to an embodiment of the present invention, and FIG. 2 is a perspective view of a longitudinal section of FIG. 1. FIG. 3 is a longitudinal sectional view of the battery cell 1 of FIG. 1.

[0044] Referring to FIG. 1, a battery cell 1 according to an embodiment of the present invention includes an electrode assembly 10, a battery housing 20, and a housing cover 30. The said battery cell 1 may further include a current collector 40 among other things. The present invention is not limited by the shape of the battery and is also applicable to other shaped batteries, for example, prismatic batteries.

[0045] Referring to FIGS. 2 and 3, the electrode assembly 10 includes a first electrode tab 11 and a second electrode tab 12. Specifically, the electrode assembly 10 includes a first electrode and a second electrode, and a separator interposed therebetween. The electrode assembly 10 has a structure in which the first electrode, the second electrode, and the separator interposed therebetween are wound around a winding axis with a separator interposed therebetween, thereby defining a core and an outer peripheral surface. That is, the electrode assembly 10 applied to the present invention can be a jelly roll type electrode assembly 10. In this case, a separator may be further provided on the outer peripheral surface of the electrode assembly 10 for insulation from the battery housing 20. The electrode assembly 10 can be applied without limitation to a known winding structure in the art.

[0046] On the other hand, in the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate can be used without limitation as long as they are known active materials in the art.

[0047] Referring to FIGS. 1 and 2, the battery housing 20 is a substantially cylindrical container having an opening formed on one side, and is made of a conductive metal material. The side surface of the battery housing 20 and the lower surface located on the opposite side of the opening are usually integrally formed. That is, the battery housing 20 usually has a form in which the upper end in the height direction is open and the lower end is closed. The lower surface of the battery housing 20 can have a substantially flat form. The battery housing 20 houses the electrode assembly 10 from an opening formed on one side in the height direction. The battery housing 20 can also house the electrolyte together from the opening.

[0048] The battery housing 20 may include a beading portion 21 formed at an end adjacent to an open portion provided at the upper end of the battery housing 20. The battery housing 20 may further include a crimping portion 22 formed on the beading portion 21. The beading portion 21 has a form in which the periphery of the outer peripheral surface of the battery housing 20 is press-fitted at a predetermined depth. More specifically, the beading portion 21 may have a form in which it is press-fitted inward in a region between an open portion formed on one side of the battery housing 20 and a housing portion that houses the electrode assembly 10.

[0049] The beading portion 21 is formed on the upper part of the electrode assembly 10. The inner diameter of the battery housing 20 in the region where the beading portion 21 is formed is formed smaller than the diameter of the electrode assembly 10.

[0050] The beading portion 21 provides a support surface on which the housing cover 30 is mounted. Also, the beading portion 21 may provide a support surface on which at least a part of the peripheral edge of the current collector 40 is mounted and coupled. That is, at least a part of the peripheral edge of the current collector 40 of the present invention and / or the peripheral edge of the housing cover 30 may be mounted on the upper surface of the beading portion 21. In order to stably support at least a part of the peripheral edge of the current collector 40 and / or the peripheral edge of the housing cover 30, the upper surface of the beading portion 21 may have a form extending in a direction substantially parallel to the lower surface of the battery housing 20, that is, in a direction substantially perpendicular to the side wall of the battery housing 20.

[0051] The beading portion 21 can function as a support portion on which the housing cover 30 is mounted, so that the electrode assembly 10 having a size substantially corresponding to the inner diameter of the battery housing 20 does not fall out from the opening formed at the upper end of the battery housing 20. The upper beading portion 21 can function as a support portion not only for the housing cover 30 but also for fixing the current collector 40, the sealing gasket G1, and the like.

[0052] The crimping portion 22 is formed on the upper part of the beading portion 21. The crimping portion 22 has a form that extends and bends so as to surround the peripheral edge of the housing cover 30 disposed on the upper part of the beading portion 21. Due to such a shape of the crimping portion 22, the housing cover 30 is fixed on the beading portion 21.

[0053] Referring to FIGS. 1 to 3, the housing cover 30 covers the opening formed on one side of the battery housing 20. The housing cover 30 can be fixed by the crimping portion 22 formed at the upper end of the battery housing 20. In this case, in order to improve the fixing force and the sealing property of the battery housing 20, a sealing gasket G1 may be interposed between the battery housing 20 and the housing cover 30 and between the current collector 40 and the housing cover 30. In this case, the contact portion 33a and / or the second contact portion may be interposed between the beading portion 21 of the battery housing 20 and the sealing gasket G1. Thus, the contact portion 33a and / or the second contact portion interposed between the beading portion 21 and the sealing gasket G1 can be fixed by bending the crimping portion 22 extending upward from the beading portion 21.

[0054] The housing cover 30 may be substantially circular plate-shaped. More specifically, the housing cover 30 may include a flat portion that is a flat central region, a flange portion that is a region surrounded by the sealing gasket G1 and / or the crimping portion 22, and a connecting portion that connects the flat portion and the flange portion. The flat portion and the flange portion may be configured to be substantially parallel to the lower surface of the battery housing 20. Here, the position in the central axis direction of the flat portion may be above the position in the central axis direction of the flange portion. Accordingly, the connecting portion may have an inclined form that connects the flat portion and the flange portion.

[0055] On the one hand, in the present invention, the housing cover 30 does not necessarily have to function as a current path. If the battery housing 20 and the housing cover 30 can be firmly fixed by welding or fixing by applying other components and the airtightness of the open portion of the battery housing 20 can be ensured, the application of such a sealing gasket G1 is not essential.

[0056] Referring to FIGS. 1 to 3, the housing cover 30 includes a vent portion 31 and a deformation induction portion 32.

[0057] Referring to FIGS. 1 to 3, the vent portion 31 may be formed to prevent an increase in the internal pressure due to the gas generated inside the battery housing 20. The vent portion 31 may be configured to determine that the internal pressure of the battery housing 20 has increased above a certain level. The vent portion 31 may be configured to break when the internal pressure of the battery housing 20 increases above a certain level. For example, the vent portion 31 may be formed in a part of the housing cover 30 and may be a region that is structurally weaker than the surrounding region so that it can be easily broken when internal pressure is applied. The vent portion 31 may be, for example, a region having a thickness thinner than the surrounding region.

[0058] That is, for any reason, a thermal event may occur inside the battery cell 1 to generate vent gas, and the vent gas may increase the internal pressure of the battery housing 20. At this time, since the vent portion 31 is structurally weaker than the surrounding region so that it can be easily broken when the internal pressure of the battery cell 1 increases, when vent gas is generated, breakage can occur at the vent portion 31.

[0059] Referring to FIGS. 1 to 3, the deformation guiding portion 32 can be provided at a position separated from the vent portion 31 by a predetermined distance in the radial direction. Desirably, as shown in FIGS. 1 to 3, it can be provided inside the vent portion 31 in the radial direction. The deformation guiding portion 32 can be configured to be deformed when the internal pressure of the battery housing 20 increases to a certain level or more. In particular, the deformation guiding portion 32 can be configured to induce preferential deformation of the housing cover 30 in the region where the deformation guiding portion 32 is formed when the internal pressure of the battery housing 20 increases to a certain level or more.

[0060] According to such a configuration, stress can act on the deformation guiding portion 32 by the vent gas generated inside the battery cell 1, and deformation of the deformation guiding portion 32 can be induced. Thereby, deformation of the shape of the vent portion 31 can be minimized. Therefore, deformation of the flange portion is suppressed, and leakage of the battery cell 1 such as electrolyte to the outside can be prevented.

[0061] FIG. 4 is a diagram for explaining the housing cover 30 according to an embodiment of the present invention.

[0062] Referring to FIGS. 1 to 4, the vent portion 31 can be configured to form a substantially circular closed loop. Thereby, when vent gas is ejected inside the battery cell 1 and the housing cover 30 receives internal pressure upward, the vent portion 31 is broken and the inner region of the circular closed loop of the housing cover 30 is torn. Thereby, venting is performed smoothly.

[0063] On the other hand, referring to FIGS. 1 to 4, the deformation guiding portion 32 can be configured to form a substantially circular closed loop. Thereby, when vent gas is ejected inside the battery cell 1 and the housing cover 30 receives internal pressure upward, deformation of the deformation guiding portion 32 can be performed. At this time, since the deformation guiding portion 32 is configured to form a substantially circular closed loop, deformation of the deformation guiding portion 32 becomes easy.

[0064] On the other hand of the present invention, the vent portion 31 and the deformation guiding portion 32 may be provided in a flat portion which is a flat central region of the housing cover 30.

[0065] For example, referring to FIGS. 1 to 4, it can be confirmed that the deformation guiding portion 32 and the vent portion 31 are provided in the flat portion of the housing cover 30.

[0066] According to such a structure, since the breakage of the vent portion 31 and the deformation and / or breakage of the deformation guiding portion 32 occur in the flat region, the shapes of the flange portion and the connecting portion are minimized in deformation. In particular, it is possible to suppress the deformation of the flange portion from a shape substantially parallel to the lower surface of the battery housing 20 to an inclined shape. As a result, the deformation of the flange portion is suppressed, and it is possible to prevent the leakage of the electrolyte or the like to the outside of the battery cell 1.

[0067] On yet another aspect of the present invention, the deformation guiding portion 32 may be provided inside the vent portion 31 in the radial direction. This will be described in detail below with reference to FIGS. 5 and 6 which are comparative examples of the present invention, and FIGS. 7 and 8 which are an embodiment of the present invention.

[0068] FIG. 5 is a diagram for explaining the housing cover 30 which is a comparative example of the present invention, and FIG. 6 is a diagram for explaining the process in which the housing cover 30 of FIG. 5 receives pressure by the vent gas. On the other hand, FIG. 7 is a diagram for explaining the housing cover 30 according to an embodiment of the present invention, and FIG. 8 is a diagram for explaining the process in which the housing cover 30 of FIG. 7 receives pressure by the vent gas.

[0069] Referring to FIGS. 5 and 6, in the conventional housing cover 30, only the vent portion 31 is provided without the deformation induction portion 32. According to such a structure, when vent gas is generated inside the battery cell 1 and the internal pressure of the battery cell 1 increases, stress concentrates on the vent portion 31 and breaks. However, in the process of the vent portion 31 breaking, the housing cover 30 receives upward pressure and warps. At this time, both directions are inclined with respect to the vent portion 31 as can be seen from FIG. 6. As a result, the connecting portion and the flange portion are also affected, and the connecting portion and the flange portion are also deformed so as to be inclined at a predetermined angle with the lower surface of the battery housing 20. In particular, the flange portion is deformed to have a shape inclined at a predetermined angle with the lower surface of the battery housing 20, and thereby a gap is generated between the flange portion and the sealing gasket G1, and ultimately, there may be a problem that the electrolyte or the like leaks to the outside of the battery cell 1.

[0070] In contrast, the housing cover 30 of the present invention includes, together with the vent portion 31, a deformation induction portion 32 provided at a position separated from the vent portion 31 by a predetermined distance in the radial direction. At this time, as shown in FIG. 7, the deformation induction portion 32 may be provided inside the vent portion 31 in the radial direction.

[0071] Referring to FIG. 7, the deformation induction portion 32 may be, for example, a shape recessed inward from the surface of the housing cover 30. For example, the deformation induction portion 32 may be in the shape of a groove or a notch. On the other hand, the recessed shape is not limited to a U-shape or a V-shape, and any structure recessed inward from the surface of the housing cover 30 is included in the scope of the present invention. Further, the shape of the deformation induction portion 32 is not limited to a groove or a notch, and any shape having a strength weaker than that of the peripheral region and being more easily deformed than the peripheral region may be included in the scope of the deformation induction portion 32 of the present invention.

[0072] According to such a structure, even if the internal pressure of the battery cell 1 increases, not only the vent portion 31 but also the deformation induction portion 32 receives stress. As a result, the shape of the deformation induction portion 32 can be deformed. In particular, when the deformation induction portion 32 is provided inside the vent portion 31 in the radial direction, the deformation of the deformation induction portion 32 can become remarkable. That is, by providing the position of the deformation induction portion 32 inside the vent portion 31 in the radial direction, the deformation of the deformation induction portion 32 can be maximized. That is, according to the present invention, since the deformation induction portion 32 has a structure that warps instead of the vent portion 31, the warping of the vent portion 31 is suppressed. As a result, deformation of the peripheral region of the vent portion 31, particularly the flange portion, is prevented. As a result, since the flange portion is not deformed, the risk of leakage of the electrolytic solution or the like is also reduced.

[0073] FIG. 9 is a diagram for explaining the specific shape of the housing cover 30 according to an embodiment of the present invention.

[0074] On still another aspect of the present invention, the deformation induction portion 32 can be provided in a region between the central point of the housing cover 30 and a point that is about 70% of the radius of the housing cover 30.

[0075] For example, the housing cover 30 shown in FIG. 9 according to an embodiment of the present invention has a radius of about 21.6 mm, and the vent portion 31 is provided at a point about 14.9 mm away from the center of the housing cover 30. The deformation induction portion 32 is provided in a region between the center of the housing cover 30 and a point about 14.9 mm away from the center. In terms of ratio, the vent portion 31 is provided at a point that is about 70% of the radius of the housing cover 30 based on the center of the housing cover 30, and the deformation induction portion 32 is provided in a region between the central point of the housing cover 30 and a point that is 70% of the radius of the housing cover 30. That is, according to the above characteristics, the deformation induction portion 32 can be provided inside the vent portion 31 in the radial direction.

[0076] Thus, according to the structure in which the deformation guiding portion 32 is provided in the region between the central point of the housing cover 30 and the point that is 70% of the radius of the housing cover 30, compared with the case where the deformation guiding portion 32 is provided in the outer region of the point that is 70% of the radius of the housing cover 30, the flatness of the flange portion can be ensured. If the deformation guiding portion 32 is provided outside the said region, the deformation guiding portion 32 will be located outside the vent portion 31, and a greater stress can act on the deformation guiding portion 32 than on the vent portion 31. That is, since the deformation guiding portion 32, which is the region where deformation occurs, is closer to the flange portion, the deformation of the flange portion can become more severe. Also, a greater stress acts on the deformation guiding portion 32 than on the vent portion 31, and breakage can occur at the deformation guiding portion 32 instead of the vent portion 31. However, according to the present invention, since the deformation guiding portion 32 where deformation occurs is far from the flange portion, it is possible to suppress the deformation of the flange portion.

[0077] Desirably, the deformation guiding portion 32 can be provided in the region between the point that is about 20% of the radius of the housing cover 30 and the point that is about 60% of the radius of the housing cover 30. That is, the length in the radial direction between the deformation guiding portion 32 and the vent portion 31 can be about 10 - 50% of the length in the radial direction of the housing cover 30.

[0078] For example, referring to the housing cover 30 shown in FIG. 9 according to an embodiment of the present invention, when the deformation guiding portion 32 is provided in the region between the point that is about 20% of the radius of the housing cover 30 from the center of the housing cover 30 and the point that is 60% of the radius of the housing cover 30 from the center of the housing cover 30, the vent pressure acting on the vent portion 31 can be ensured to be the lowest. In this case, since the vent portion 31 is provided at the point that is about 70% of the radius of the housing cover 30 with respect to the center of the housing cover 30, the length in the radial direction between the deformation guiding portion 32 and the vent portion 31 can be about 10 - 50% of the length in the radial direction of the housing cover 30.

[0079] More preferably, when the deformation induction part 32 is provided in a region between a point that is about 23% of the radius of the housing cover 30 from the center of the housing cover 30 and a point that is about 46% of the radius of the housing cover 30 from the center of the housing cover 30, the vent pressure acting on the vent part 31 can be ensured to be even lower.

[0080] That is, according to the present invention, in addition to the vent 31, by further providing the deformation induction part 32 and inducing the deformation of the deformation induction part 32, it is possible to minimize the deformation of the peripheral region of the vent part 31. That is, it is possible to suppress the leakage of the electrolytic solution due to the slippage of the flange part. Further, according to the present invention, by applying the deformation induction part 32, the warping of the flat part can be suppressed and the flatness of the housing cover 30 can be ensured.

[0081] Furthermore, according to the present invention, by using the deformation induction part 32, the time point at which the vent part 31 breaks can be adjusted. That is, it is possible to expect the adjustment of the vent pressure due to the double structure of the vent part 31 and the deformation induction part 32.

[0082] For reference, in this specification, in order to describe an embodiment of the present invention, the housing cover 30 with specific specifications has been described as an example. However, the scope of the rights of the present invention is not limited to only the housing cover 30 of the above specifications. It goes without saying that the scope of the rights of the present invention also extends to other specifications of the housing cover 30 in which the relative positions of the vent part 31 and / or the deformation induction part 32 are in the same ratio as the above embodiment.

[0083] FIG. 10 is a diagram for explaining the housing cover 30 according to another embodiment of the present invention, and FIG. 11 is a diagram for explaining the housing cover 30 according to still another embodiment of the present invention.

[0084] The housing cover 30 according to the present embodiment is similar to the housing cover 30 of the above-described embodiment. Therefore, the overlapping explanations for the substantially same or similar configurations as the above-described embodiment are omitted. Hereinafter, the description will be centered on the differences from the above-described embodiment.

[0085] According to one aspect of the present invention, the deformation inducing portion 32 may include at least one of an upper deformation inducing portion N1 provided on the upper surface of the housing cover 30 and a lower deformation inducing portion N2 provided on the lower surface of the housing cover 30.

[0086] For example, as shown in FIG. 10, the deformation inducing portion 32 may include only the upper deformation inducing portion N1 provided on the upper surface of the housing cover 30. As another embodiment, as shown in FIG. 11, the deformation inducing portion 32 may include only the lower deformation inducing portion N2 provided on the lower surface of the housing cover 30. As yet another embodiment, as shown in FIG. 7, the deformation inducing portion 32 may include both the upper deformation inducing portion N1 provided on the upper surface of the housing cover 30 and the lower deformation inducing portion N2 provided on the lower surface of the housing cover 30.

[0087] When the deformation inducing portion 32 is provided on both surfaces of the housing cover 30, the vent pressure can be minimized. On the other hand, when the deformation inducing portion 32 is provided only on the lower surface of the housing cover 30, the vent pressure can be maximized. As a result, the magnitude of the vent pressure depending on the formation position of the deformation inducing portion 32 is large in the order of when the deformation inducing portion 32 is provided only on the lower surface, when the deformation inducing portion 32 is provided only on the upper surface, and when the deformation inducing portion 32 is provided on both surfaces.

[0088] On the other hand, when the vent pressure is low, since it may be vented as soon as a thermal event occurs, it may be advantageous in terms of safety. Also, when it is vented immediately, the time for the deformation of the flange portion to occur is reduced, so that the deformation of the flange portion can be minimized. Thereby, risks such as leakage of the electrolytic solution are reduced. As a result, according to the present invention, the vent pressure can be adjusted by applying the deformation inducing portion 32. Also, according to the present invention, the flatness of the flange portion can be ensured.

[0089] FIG. 12 is a diagram for explaining a housing cover 30 according to still another embodiment of the present invention.

[0090] In one aspect of the present invention, the thickness of the housing cover 30 in the region where the deformation guiding portion 32 is formed may be configured to be greater than the thickness of the housing cover 30 in the region where the vent portion 31 is formed.

[0091] For example, referring to FIG. 12, the thickness of the region where the deformation guiding portion 32 is formed may be greater than the thickness of the region where the vent portion 31 is formed. Usually, in order to adjust the bending timing, the size of the notch, that is, the thickness between notches can be adjusted. If the thickness between notches is small, the vent portion 31 is likely to be broken, and if the thickness between notches is large, the vent portion 31 is less likely to be broken. Therefore, when configuring the deformation guiding portion 32, the breaking timing can be adjusted by adjusting the thickness between notches.

[0092] According to the present invention, since the thickness of the region where the deformation guiding portion 32 is formed is greater than the thickness of the region where the vent portion 31 is formed, the vent portion 31 is more easily broken than the deformation guiding portion 32. Thus, even when pressure is generated by vent gas, the vent portion 31 is preferentially broken and the deformation guiding portion 32 is not preferentially broken.

[0093] The deformation guiding portion 32 can serve to adjust the breaking timing of the vent portion 31 by changing its shape before and after the breaking of the vent portion 31. For example, when stress acts on the deformation guiding portion 32, the peripheral region of the deformation guiding portion 32 can be deformed from a flat shape to a shape bent with respect to the deformation guiding portion 32. At the same time, the peripheral region of the deformation guiding portion 32 can be inclined in both directions with respect to the deformation guiding portion 32. That is, by deforming the shape of the deformation guiding portion 32 instead of the shape of the vent portion 31, the shape of the vent portion 31 is preserved, and thereby the floating of the flange portion can be suppressed. As a result, leakage of the battery cell 1 such as electrolyte to the outside can be prevented.

[0094] FIG. 13 is a diagram for explaining the shape of the deformation guiding portion 32 according to an embodiment of the present invention, and FIG. 14 is a diagram for explaining the shape of the deformation guiding portion 32 according to another embodiment of the present invention.

[0095] Since the housing cover 30 according to the present embodiment is similar to the housing cover 30 of the above-described embodiment, redundant explanations for substantially the same or similar configurations as those of the above-described embodiment will be omitted, and hereinafter, the description will be centered on the differences from the above-described embodiment.

[0096] Referring to FIG. 13, the deformation guiding portion 32 may include an upper deformation guiding portion N1 provided on the upper surface of the housing cover 30 and a lower deformation guiding portion N2 provided on the lower surface of the housing cover 30. As another embodiment of the present invention, as shown in FIG. 14, the upper deformation guiding portion N1 and the lower deformation guiding portion N2 may be provided offset from each other.

[0097] According to the structure as shown in FIG. 14, since the upper deformation guiding portion N1 and the lower deformation guiding portion N2 are provided offset from each other, the stress applied to the region between the upper deformation guiding portion N1 and the lower deformation guiding portion N2 may be predominantly shear stress. On the other hand, when the upper deformation guiding portion N1 and the lower deformation guiding portion N2 are provided on the same line as in the housing cover 30 shown in FIG. 13, the stress applied to the region between the upper deformation guiding portion N1 and the lower deformation guiding portion N2 may be predominantly tensile stress. If the region between the upper deformation guiding portion N1 and the lower deformation guiding portion N2 is under the same magnitude of pressure, deformation is more likely to occur when shear stress is applied compared to when tensile stress is applied. Therefore, according to the present invention, the deformation of the deformation guiding portion 32 becomes easier even under a lower vent pressure. Or, by having the upper deformation guiding portion N1 and the lower deformation guiding portion N2 offset from each other, it becomes possible to ensure the same amount of deformation with a smaller amount of molding. As a result, by reducing the amount of molding, damage to the mold is reduced, and an increase in the lifespan of the housing cover 30 can be expected.

[0098] FIG. 15 is a table for explaining a cross section of a 2D model to which the deformation induction part 32 is applied, and FIG. 16 is a table showing the experimental results of confirming the deformation state of the vent part 31 by 2D static analysis of the model of FIG. 15.

[0099] FIG. 15 shows cross sections from the center to one end of the housing cover 30 for each case. For example, the housing cover 30 shown in FIG. 15 has a radius of about 21.6 mm, and the vent part 31 is provided at a point about 14.9 mm away from the center of the housing cover 30. The deformation induction part 32 is provided in a region between the center of the housing cover 30 and the point about 14.9 mm away from the center. In terms of ratio, the vent part 31 is provided at a point that is about 70% of the radius of the housing cover 30 from the center of the housing cover 30, and the deformation induction part 32 is provided in a region between the center of the housing cover 30 and the point that is about 70% of the radius of the housing cover 30.

[0100] Referring to FIGS. 15 and 16, it can be confirmed that the vent pressure is shown to be the highest in the conventional housing cover 30 not provided with the deformation induction part 32, and in the case where the deformation induction part 32 is provided in the region toward the center in the radial direction with the vent part 31 as a reference, the vent pressure is shown to be relatively small.

[0101] That is, as can be seen from the above results, according to the present invention to which the deformation induction part 32 is applied, the vent pressure can be reduced. When having a low vent pressure, since venting can occur as soon as a thermal event occurs, it can be advantageous in terms of safety. Also, when venting occurs immediately, the time for the deformation of the flange part to occur is reduced, so that the deformation of the flange part can be minimized. As a result, risks such as electrolyte leakage are reduced. As a result, according to the present invention, the vent pressure can be adjusted by applying the deformation induction part 32. Also, according to the present invention, the flatness of the flange part can be ensured.

[0102] Referring to FIGS. 15 and 16, more desirably, when the deformation-inducing portion 32 is provided between a point approximately 5 mm away from the center of the housing cover 30 (a point that is approximately 23% of the radius of the housing cover 30 from the center of the housing cover 30) and a point approximately 13 mm away from the center of the housing cover 30 (a point that is approximately 60% of the radius of the housing cover 30 from the center of the housing cover 30), it can be confirmed that the vent pressure acting on the vent portion 31 is the lowest. In particular, when the deformation-inducing portion 32 is provided between a point approximately 5 mm away from the center of the housing cover 30 (a point that is approximately 23% of the radius of the housing cover 30 from the center of the housing cover 30) and a point approximately 10 mm away from the center of the housing cover 30 (a point that is approximately 46% of the radius of the housing cover 30 from the center of the housing cover 30), it can be confirmed that the vent pressure acting on the vent portion 31 is lower.

[0103] However, when both sides are provided with the deformation-inducing portion 32 at a point approximately 10 mm away from the center of the housing cover 30 (a point that is approximately 46% of the radius of the housing cover 30 from the center of the housing cover 30), the vent pressure acting on the vent portion 31 was the lowest. In this case, however, the maximum stress acted on the deformation-inducing portion 32 rather than the vent portion 31. That is, in this case, the deformation-inducing portion 32 may break. Therefore, it is important that the position where the maximum stress is generated is the vent portion 31 and the deformation-inducing portion 32 is provided within an appropriate range where the vent pressure can be reduced.

[0104] Referring to FIGS. 1 and 2, the current collector 40 according to an embodiment of the present invention is housed inside the battery housing 20, is electrically connected to the electrode assembly 10, and is also electrically connected to the battery housing 20. That is, the current collector 40 electrically connects the electrode assembly 10 and the battery housing 20.

[0105] FIG. 17 is a diagram for explaining the battery pack 3 including the battery cell 1 of FIG. 1.

[0106] Referring to FIG. 17, a battery pack 3 according to an embodiment of the present invention includes a battery assembly in which a plurality of battery cells 1 according to an embodiment of the present invention as described above are electrically connected, and a pack housing 2 that houses the battery assembly. In the drawings of the present invention, for convenience of illustration, components such as bus bars, cooling units, and power terminals for electrical connection are omitted. That is, the battery pack 3 may further include components of a known battery pack 3 at the time of filing of the present invention, such as a BMS, a pack case, a relay, a current sensor, and the like.

[0107] FIG. 18 is a diagram for explaining an automobile 5 including the battery pack 3 of FIG. 17.

[0108] Referring to FIG. 18, an automobile 5 according to an embodiment of the present invention is, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and may include a battery pack 3 according to an embodiment of the present invention. The automobile 5 includes four-wheel automobiles and two-wheel automobiles. The automobile 5 operates by receiving power from a battery pack 3 according to an embodiment of the present invention. The automobile 5 according to the present invention may further include various other components included in the automobile 5 in addition to such a battery pack 3. For example, the automobile 5 according to the present invention may further include a vehicle body, a motor, a control device such as an electronic control unit (ECU), and the like in addition to the battery pack 3 according to the present invention.

[0109] In various embodiments as described above, even if venting occurs due to an abnormal phenomenon of the battery cell 1, the present invention can minimize the deformation of the peripheral region of the vent portion 31 by applying the deformation guiding portion 32. That is, it is possible to suppress the leakage of the electrolyte due to the slippage of the flange portion. Further, according to the present invention, by applying the deformation guiding portion 32, it is possible to suppress the warping of the flat portion and ensure the flatness of the housing cover 30. Furthermore, according to the present invention, it is possible to adjust the timing at which the vent portion 31 breaks by using the deformation guiding portion 32. That is, it is possible to expect the adjustment of the vent pressure by the double-notch structure of the vent portion 31 and the deformation guiding portion 32.

[0110] In addition, in this specification, terms indicating directions such as up and down are used, but such terms indicate relative positions and are only for convenience of explanation, and it is obvious to those skilled in the art that they can vary depending on the position of the object in question, the position of the observer, etc.

[0111] As described above, the present invention has been described with reference to limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations are possible within the equivalent scope of the technical idea of the present invention and the scope of the claims described below by those having ordinary knowledge in the technical field to which the present invention pertains.

Explanation of Reference Numerals

[0112] 1 Battery cell 2 Pack housing 3 Battery pack 5 Automobile 10 Electrode assembly 11 First non-coated portion 12 Second non-coated portion H1 Take-up hole 20 Battery housing 21 Beading portion 22 Crimping portion 30 Housing cover 31 Vent portion 32 Deformation induction portion N1 Upper deformation induction portion N2 Lower deformation induction portion G1 Sealing gasket 40 Current collector H2 Current collector hole

Claims

1. An electrode assembly including a first electrode, a second electrode, and a separation membrane interposed between the first electrode and the second electrode; A battery housing that houses the electrode assembly from an opening formed on one side; A housing cover including a vent portion configured to cover the opening and break when the internal pressure of the battery housing increases to a certain level or more, and a deformation induction portion spaced a predetermined distance from the vent portion in the radial direction and provided inside the vent portion in the radial direction; A battery cell including the above.

2. The battery cell according to claim 1, wherein the deformation induction portion induces the housing cover in the region where the deformation induction portion is formed to be preferentially deformed when the internal pressure of the battery housing increases to a certain level or more.

3. The battery cell according to claim 1, wherein the deformation induction portion forms a circular closed loop.

4. The battery cell according to claim 1, wherein the vent portion and the deformation induction portion are provided in a flat portion that is a flat central region of the housing cover.

5. The battery cell according to claim 1, wherein the deformation induction portion is provided in a region between the center point of the housing cover and a point that is 70% of the radius of the housing cover.

6. The battery cell according to claim 1, wherein the deformation induction portion is provided in a region between a point that is 20% of the radius of the housing cover and a point that is 60% of the radius of the housing cover.

7. The battery cell according to claim 1, wherein the length in the radial direction between the deformation induction portion and the vent portion is 10% to 50% of the length in the radial direction of the housing cover.

8. The battery cell according to claim 1, wherein the deformation induction portion includes at least one of an upper deformation induction portion provided on the upper surface of the housing cover and a lower deformation induction portion provided on the lower surface of the housing cover.

9. The battery cell according to claim 1, wherein the deformation induction portion includes an upper deformation induction portion provided on the upper surface of the housing cover and a lower deformation induction portion provided on the lower surface of the housing cover.

10. The battery cell according to claim 1, characterized in that the thickness of the housing cover in the region where the deformation-inducing part is formed is larger than the thickness of the housing cover in the region where the vent part is formed.

11. The battery cell according to claim 9, characterized in that the upper deformation-inducing part and the lower deformation-inducing part are provided so as to be displaced from each other.

12. A battery pack, characterized by including at least one battery cell according to any one of claims 1 to 11.

13. An automobile, characterized by including at least one battery pack according to claim 12.

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