Secondary battery and battery box including same

Abstract

The present invention relates to a secondary battery and a battery box including same. The secondary battery according to one aspect of the present invention comprises: an electrode assembly extending in one direction; a cap including a cover portion that covers one side of the electrode assembly in the extension direction; an exterior film that surrounds the peripheral side of the electrode assembly; and an insulating member that occupies at least a portion of the inner space defined by the cap-side surface of the electrode assembly, the electrode assembly-facing inner surface of the cap, and the inner surface of the exterior film, wherein the insulating member may include a resin having a melting point of 130°C to 350°C.

Description

Secondary battery and battery box including the same

[0001] The present invention relates to a secondary battery and a battery box including the same, and more specifically, to a secondary battery capable of charging and discharging electrical energy and a battery box including the same.

[0002]

[0003] Although secondary batteries have been applied to small-scale fields such as mobile devices and laptop computers, recently the direction of research has expanded to medium and large-scale fields, and they are widely used in fields requiring high voltage and large capacity, such as Energy Storage Systems (ESS) and Electric Vehicles (EV).

[0004] Meanwhile, as secondary batteries are utilized in various devices, the demand for their stability is increasing. To enhance the stability of secondary batteries, it is necessary to control the direction in which internal gases or flames are discharged during abnormal situations where the battery's temperature or pressure rises. This is because controlling the discharge direction of gases or flames allows for the suppression or control of thermal transfer or thermal runaway phenomena.

[0005]

[0006] The embodiments of this specification are intended to provide a secondary battery that has fewer restrictions on shape, improved battery capacity, reduced amount of moisture entering from the outside, and improved structural stability.

[0007] The embodiments of this specification are intended to provide a secondary battery with improved safety by controlling the direction in which gas or flame generated inside the secondary battery may be ejected, thereby preventing ejection toward the cap and delaying the time for the flame to propagate to adjacent cells.

[0008]

[0009] [1] According to one aspect, a secondary battery is provided comprising: an electrode assembly extending in one direction; a cap including a cover portion covering one side of the extension direction of the electrode assembly; an outer film surrounding the periphery side of the electrode assembly; and an insulating member occupying at least a portion of an internal space defined by the cap-direction surface of the electrode assembly, the inner surface of the cap facing the electrode assembly, and the inner surface of the outer film, wherein the insulating member comprises a resin having a melting point of 130°C to 350°C.

[0010] [2] In the above [1], the resin has a density of 0.80 g / cm³ 3 Up to 2.50 g / cm³ 3 It could be.

[0011] [3] In the above [1] and / or [2], the resin may have a melting point of 150°C to 350°C.

[0012] [4] In at least one of [1] to [3] above, the resin has a density of 1.20 g / cm³ 3 Up to 3.00 g / cm³ 3 It could be.

[0013] [5] In at least one of [1] to [4] above, the resin may comprise one or more selected from the group consisting of polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene (PP), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE).

[0014] [6] In at least one of [1] to [5] above, the insulating member may comprise a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin.

[0015] [7] In at least one of [1] to [6] above, the insulating member may include a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin, the heat-resistant resin may have a melting point of 200°C to 350°C, and the coating material may have a melting point of 130°C to 200°C.

[0016] [8] In at least one of [1] to [7] above, the insulating member may comprise a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin, and the heat-resistant resin may comprise one or more selected from the group consisting of polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE), and the coating material may comprise polypropylene (PP).

[0017] [9] In at least one of [1] to [8] above, the resin may further comprise one or more selected from the group consisting of inorganic particles, polyurethane foam, polystyrene foam, silicone foam, phenolic foam and aerogel.

[0018]

[0010] In at least one of [1] to [9] above, the insulating member may be disposed in at least a part of the internal space, but not in contact with the cap-direction surface of the electrode assembly.

[0019]

[0011] In at least one of [1] to

[0010] above, the insulating member may be disposed in at least a part of the internal space and may be disposed to be in contact with at least one of the inner surface of the outer film and the inner surface facing the electrode assembly of the cap.

[0020]

[0012] In at least one of [1] to

[0011] above, the secondary battery may further include an electrode tab assembly extending from the electrode assembly to the cap side, and the insulating member may be divided into a first insulating member and a second insulating member with the electrode tab assembly in between.

[0021]

[0013] In at least one of [1] to

[0012] above, the secondary battery may further include an electrode tab assembly extending from the electrode assembly to the cap side, and the insulating member may be coated on at least one part of one or more surfaces selected from the electrode tab assembly, the inner surface of the outer film and the inner surface of the cap facing the electrode assembly.

[0022]

[0014] In at least one of [1] to

[0013] above, the first insulating member and the second insulating member may have a shape that is symmetrical with respect to the electrode tab assembly.

[0023]

[0015] According to another aspect, a battery box is provided comprising: a secondary battery; and a packaging that accommodates the secondary battery, wherein the secondary battery comprises: an electrode assembly extending in one direction; a cap including a cover portion covering one side of the extension direction of the electrode assembly; an outer film wrapping around the periphery side of the electrode assembly; and an insulating member occupying at least a portion of an internal space defined by the cap-direction surface of the electrode assembly, the inner surface of the cap facing the electrode assembly, and the inner surface of the outer film, wherein the insulating member comprises a resin having a melting point of 130°C to 350°C.

[0024]

[0025] According to one aspect of the present invention, since an insulating member is provided in the internal space formed between the cap and the electrode assembly, the movement of gas or flame in the direction from the electrode assembly toward the cap can be suppressed. Through this, in abnormal situations, the direction of discharge of gas or flame is guided toward the outer film, and the discharge itself is delayed to slow down propagation to adjacent cells, thereby securing evacuation time for a user of an electric device equipped with the battery, and thus the stability of the secondary battery can be improved.

[0026] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the attached drawings.

[0027]

[0028] FIG. 1 is a perspective view of a battery box according to one embodiment of the present invention. In this case, the packaging is indicated by a dotted line, and the configuration visible through the packaging is indicated by a solid line.

[0029] Figure 2 is a perspective view of a secondary battery viewed from the top.

[0030] Figure 3 is a cross-sectional view according to II of Figure 2.

[0031] FIG. 4 is an exploded perspective view of a secondary battery according to a first embodiment of the present invention.

[0032] FIG. 5 is a perspective view of the first and second insulating members of a secondary battery according to the first embodiment of the present invention, viewed from the front.

[0033] FIG. 6 is a perspective view of the first and second insulating members of a secondary battery according to the first embodiment of the present invention, viewed from the rear.

[0034] FIG. 7 is a cross-sectional view of a secondary battery according to the first embodiment of the present invention, cut according to II of FIG. 2.

[0035] FIG. 8 is a cross-sectional view according to II-II of FIG. 7.

[0036] Figure 9 is an enlarged view of part A of Figure 7.

[0037] FIG. 10 is a cross-sectional view of a secondary battery according to a second embodiment of the present invention, cut according to II of FIG. 2.

[0038] FIG. 11 is a cross-sectional view of a secondary battery according to the third embodiment of the present invention, cut according to II of FIG. 2.

[0039] FIG. 12 is an exploded perspective view of the first and second insulating members of a secondary battery according to the fourth embodiment of the present invention. At this time, the first and second insulating members are rotated so that the joint portion is clearly visible.

[0040] FIG. 13 is a cross-sectional view of a secondary battery according to the fifth embodiment of the present invention, cut according to II of FIG. 2.

[0041] FIG. 14 is a cross-sectional view of a secondary battery according to the 6th embodiment of the present invention, cut according to II of FIG. 2.

[0042]

[0043] Preferred embodiments of the present invention are described in detail so that those skilled in the knowledge can easily implement them. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0044] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0045] In addition, terms or 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 invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0046] The secondary battery and battery box according to the present specification include at least one of the configurations described below, and may include any combination of technically feasible configurations among the following configurations.

[0047]

[0048] battery box

[0049] FIG. 1 is a perspective view of a battery box according to one embodiment of the present invention. In this case, the packaging is indicated by a dotted line, and the configuration visible through the packaging is indicated by a solid line.

[0050] FIG. 1 discloses a battery box according to an embodiment of the present invention. Referring to FIG. 1, a battery box (1) according to an embodiment of the present invention may include a secondary battery (3). The secondary battery (3) may be configured to charge and discharge electrical energy. At this time, the secondary battery (3) may be a secondary battery according to an embodiment of the present invention described below.

[0051]

[0052] In this embodiment, the secondary batteries (3) may be composed of a plurality of units so that the electrical capacity or voltage of the battery box (1) can be increased. The plurality of secondary batteries (3) may be arranged in a predetermined manner. As illustrated, the plurality of secondary batteries (3) may be stacked in one direction, but the arrangement method of the secondary batteries (3) is not particularly limited.

[0053] A battery box (1) according to one embodiment of the present invention may include a packaging (2). The packaging (2) may be configured to accommodate a secondary battery (3) and protect it from external contamination or impact. To this end, the packaging (2) may have an enclosure shape. However, the structure or shape of the packaging (2) is not particularly limited as long as it can accommodate the secondary battery (3).

[0054] Meanwhile, although not specifically illustrated, parts that perform a predetermined function may be installed in the packaging (2) for the operation or safety of the battery box (1). For example, a connector or bus bar for energizing the secondary battery (3) with the outside may be installed in the packaging (2), and a vent plug for communicating the inside and outside of the packaging (2) may be installed.

[0055]

[0056] secondary battery

[0057] In one aspect, a secondary battery according to one embodiment of the present invention may include: an electrode assembly extended in one direction; a cap including a cover portion covering one side of the extension direction of the electrode assembly; an outer film surrounding the periphery side of the electrode assembly; and an insulating member occupying at least a portion of an internal space defined by the cap-direction surface of the electrode assembly, the inner surface of the cap facing the electrode assembly, and the inner surface of the outer film, and the insulating member may include a resin having a melting point of 130°C to 350°C.

[0058] In addition, the secondary battery may further include an electrode tab assembly extending from the electrode assembly toward the cap side.

[0059]

[0060] Basic structure of a secondary battery

[0061] Hereinafter, a secondary battery according to one embodiment of the present invention is described.

[0062] FIG. 2 is a perspective view of a secondary battery according to an embodiment of the present invention viewed from the top. FIG. 3 is a cross-sectional view according to II of FIG. 2. FIG. 4 is an exploded perspective view of a secondary battery according to an embodiment of the present invention. FIG. 5 is a perspective view of the first and second insulating members of a secondary battery according to a first embodiment of the present invention viewed from the front. FIG. 6 is a perspective view of the first and second insulating members of a secondary battery according to a first embodiment of the present invention viewed from the rear. FIG. 8 is a cross-sectional view according to II-II of FIG. 7. FIG. 9 is an enlarged view of portion A of FIG. 7.

[0063] Referring to FIGS. 2 and FIGS. 4, in one embodiment of the present invention, another secondary battery (3) may include an electrode assembly (10). The electrode assembly (10) may be a component responsible for charging and discharging functions.

[0064] The electrode assembly (10) may have a structure in which a plurality of anodes, cathodes, and separators are stacked in a predetermined manner. In this case, the separator may be replaced with a solid-state material. Meanwhile, the electrode assembly (10) may be classified into a jellyroll type, a stack type, or a stack & folding type depending on the stacked structure or shape. In this embodiment, the type of electrode assembly (10) is not particularly limited.

[0065] Meanwhile, the electrode assembly (10) may be extended in the front-rear direction (X-axis direction). In other words, the electrode assembly (10) may have a predetermined length in the front-rear direction (X-axis direction). Hereinafter, the above direction is referred to as the extension direction (or length direction) of the electrode assembly (10), the left-right direction (Y-axis direction) perpendicular to the above extension direction (X-axis direction) is referred to as the width direction of the electrode assembly (10), and the direction wrapping around the extension direction (X-axis direction) of the electrode assembly (10) is referred to as the circumference direction of the electrode assembly (10).

[0066] An electrode tab assembly (11) may be provided on one side of the electrode assembly (10). The electrode tab assembly (11) may be formed by assembling a plurality of electrode tabs. The electrode tabs may be components extending from an electrode, such as a negative electrode or a positive electrode. The electrode tabs may perform the function of energizing the electrodes to the outside.

[0067] In this embodiment, the electrode tab assembly (11) may extend from one side in the extension direction (X-axis direction) of the electrode assembly (10). At this time, the electrode tab assembly (11) may be composed of a plurality of them. Some of the plurality of electrode tab assemblies (11) may be formed by gathering electrode tabs connected to a positive electrode, and the remainder may be formed by gathering electrode tabs connected to a negative electrode.

[0068] Some of the multiple electrode tab assemblies (11) may be provided on one side of the extension direction (X-axis direction) of the electrode assembly (10), and the remainder may be provided on the other side of the extension direction (X-axis direction). As long as the electrode assembly (10) can be energized to the outside, the number or location of the electrode tab assemblies (11) is not particularly limited. In this embodiment, the electrode tab assemblies (11) are configured as a pair, and the description is based on the premise that the pair of electrode tab assemblies (11) are provided on each side of the electrode assembly (10).

[0069] Referring to FIGS. 2 to 4, a secondary battery (3) according to one embodiment of the present invention may include a cap (30). The cap (30) may be configured to seal the electrode assembly (10) together with an outer film (20) described later.

[0070] The cap (30) may have a certain degree of rigidity. For example, the cap (30) may be made of metal or plastic material, but is not limited thereto. As a result, the electrode assembly (10) can be protected from external impact or contamination. In addition, it can prevent the electrolyte sealed together with the electrode assembly (10) from leaking out.

[0071] The above cap (30) can cover one side of the electrode assembly (10) in the extension direction (X-axis direction). At this time, the cap (30) is composed of a pair, and the pair of caps (30) can each cover both sides of the electrode assembly (10). As a result, both sides of the electrode assembly (10) can be protected by the cap (30) having a predetermined rigidity.

[0072] Meanwhile, a pair of caps (30) may be configured symmetrically with respect to the electrode assembly (10). However, the pair of caps (30) may have different structures or sizes. Additionally, if necessary, the cap (30) may be configured as a single unit to cover one side of the electrode assembly (10), while the other side of the electrode assembly (10) may be covered by a different configuration or an outer film (20).

[0073] In the following description, it is assumed that the pair of caps (30) are configured symmetrically with respect to the electrode assembly (10). Furthermore, the description is based on the cap (30) located in front of the electrode assembly (10) (in the positive direction of the X-axis) among the pair of caps (30).

[0074] Referring again to FIGS. 2 and FIGS. 4, a secondary battery (3) according to one embodiment of the present invention may include a terminal (40). The terminal (40) may be configured to conduct electricity to the outside of the electrode assembly (10). The terminal (40) may be made of a conductive material.

[0075] The above terminal (40) may be connected through the cover portion (32) of the cap (30). An electrode tab assembly (11) may be connected to one side of the terminal (40). For example, the electrode tab assembly (11) may be welded to the terminal (40). However, the connection structure between the terminal (40) and the electrode tab assembly (11) is not particularly limited.

[0076] The terminal (40) may have a rivet shape so as not to be separated from the cap (30). Additionally, a gasket (not shown) may be provided between the terminal (40) and the cover portion (32) to ensure insulation and prevent leakage of electrolyte. If necessary, the shape or structure of the terminal (40) may be modified. Meanwhile, in this embodiment, the terminal (40) may be positioned between the first and second insulating members (50, 60) described later.

[0077] Referring to FIGS. 4 and 7, the cap (30) of a secondary battery (3) according to one embodiment of the present invention may include a cover portion (32). The cover portion (32) may be configured to cover the front (positive direction of the X-axis) of the electrode assembly (10). The cover portion (32) may have a rectangular plate shape having a predetermined thickness. However, as long as it can cover one side of the electrode assembly (10), the structure or shape of the cover portion (32) is not particularly limited.

[0078] The above cap (30) may include an extension portion (34). The extension portion (34) may be a portion extending from the cover portion (32) toward the electrode assembly (10). The extension portion (34) may be a portion that is directly coupled to the outer film (20) described later.

[0079] The above extension portion (34) may include a first extension portion (35). The first extension portion (35) may extend from the upper edge portion (positive direction of the Z-axis) of the cover portion (32) toward the electrode assembly (10). The first extension portion (35) may extend in the left-right direction (X-axis direction) along the upper edge of the cover portion (32). That is, the first extension portion (35) may have a side wall shape having a predetermined thickness.

[0080] The above extension portion (34) may include a second extension portion (36). The second extension portion (36) may extend from the lower edge portion (negative direction of the Z-axis) of the cover portion (32) toward the electrode assembly (10).

[0081] In other words, the second extension part (36) may be positioned at a predetermined distance in the vertical direction from the first extension part (35). At this time, the second extension part (36) may be extended parallel to (or parallel to) the first extension part (35). The second extension part (36) may be extended in the vertical direction (Z-axis direction) along the lower edge of the cover part (32). That is, the second extension part (36) may have a side wall shape having a predetermined thickness.

[0082] Referring to FIG. 4, in a secondary battery (3) according to one embodiment of the present invention, the extension portion (34) of the cap (30) may include a third extension portion (37). The third extension portion (37) may extend from the right edge portion (positive direction of the X-axis) of the cover portion (32) toward the electrode assembly (10). The third extension portion (37) may extend in an up-down direction (Z-axis direction) along the right edge of the cover portion (32). That is, the third extension portion (37) may have a side wall shape having a predetermined thickness.

[0083] The above extension portion (34) may include a fourth extension portion (38). The fourth extension portion (38) may extend from the left edge portion (negative direction of the X-axis) of the cover portion (32) toward the electrode assembly (10).

[0084] In other words, the fourth extension (38) may be positioned at a predetermined distance from the third extension (37) in the left-right direction (X-axis direction). At this time, the fourth extension (38) may be extended parallel to (or parallel to) the third extension (37). The fourth extension (38) may be extended in the up-down direction (Z-axis direction) along the left edge of the cover (32). That is, the fourth extension (38) may have a side wall shape having a predetermined thickness.

[0085] The first to fourth extension parts (35 to 38) can be connected to each other. The first to fourth extension parts (35 to 38) can have a ring shape overall. At this time, the ring shape may be a shape viewed in the extension direction (X-axis direction) of the electrode assembly (10).

[0086] A connecting portion, such as a resin or adhesive, may be provided on the outer surface of the cap (30). The resin may be a resin that melts upon heat or pressure. This may be intended to allow the cap (30) and the outer film (20) to be bonded together. As a result, the space enclosed by the cap (30) and the outer film (20) can be sealed.

[0087] More preferably, a connecting portion made of the resin or adhesive may be provided on the outer circumferential surface of the extension portion (34). Here, the outer circumferential surface of the extension portion (34) may be a surface facing the outer circumferential side of the electrode assembly (10) among the outer surfaces of the extension portion (34). The outer circumferential surface may be a surface wrapped by an outer film (20). Of course, if necessary, the connecting portion may also be provided on other outer surfaces of the cover portion (32) and the extension portion (34).

[0088] Referring again to FIGS. 2 to 4, a secondary battery (3) according to one embodiment of the present invention may include an outer film (20). As described above, the outer film (20) may be configured to seal the electrode assembly (10) together with a cap (30). The outer film (20) may have a certain flexibility. Accordingly, the outer film (20) may be bent or curved by an external force.

[0089] The above outer film (20) can wrap around the electrode assembly (10) in a circumferential direction. Both edge portions of the outer film (20) can be combined with a pair of caps (30) respectively. Here, the edge portions may be edge portions located on both sides of the extension direction (X-axis direction) of the electrode assembly (10). The edge portions can wrap around the outer circumferential surface of the extension portion (34) of the cap (30) in a circumferential direction of the electrode assembly (10).

[0090] The above-mentioned edge portion of the outer film (20) can be joined to the extension portion (34) by means of a connecting portion provided on the outer surface of the cap (30). In this case, if the connecting portion is made of resin, a sealing process may be performed by applying a predetermined amount of heat or pressure to join the outer film (20) and the cap (30).

[0091] As previously explained, the outer film (20) sealing the electrode assembly (10) has a certain flexibility, so it can effectively respond to deformation of the electrode assembly (10). For example, the electrode assembly (10) may increase in volume during the charging and discharging process. During this process, the outer film (20) can be bent in response to the deformation of the electrode assembly (10).

[0092] In other words, the shape of the outer film (20) can be deformed in response to the deformation of the electrode assembly (10). This prevents damage to the electrode assembly (10) by relieving the partial application of excessive force to the electrode assembly (10). In contrast, since the case of a fixed-shape prismatic secondary battery cannot be deformed in response to the deformation of the electrode assembly (10), the electrode assembly (10) may be damaged due to interference with the case.

[0093] The above-mentioned outer film (20) may be provided with a predetermined sealing portion. The sealing portion may be a portion where one edge portion and another edge portion of the outer film (20) overlap and are sealed. This may be for sealing the periphery of the electrode assembly (10).

[0094] The sealing portion of the outer film (20) can function as a passage for gas or flames to be discharged in abnormal situations. For example, when the internal pressure or temperature of the secondary battery (3) rises excessively, the sealing portion may break and gas or flames may be discharged. In this way, by directing the discharge of gas or flames to the sealing portion in abnormal situations, the stability of the secondary battery (3) can be improved.

[0095] However, in order for the discharge of gas or flame as described above to be controlled so as to be directed toward the sealing part, the thermal energy generated in the abnormal situation needs to be guided toward the circumference of the electrode assembly (10). If the thermal energy is transferred toward the extension direction of the electrode assembly (10), the connection between the cap (30) and the outer film (20) is released, and gas or flame may leak through the gap. Since this phenomenon indicates that the discharge direction of the gas and flame is not properly controlled, it may reduce the stability of the secondary battery (3).

[0096]

[0097] Insulating member

[0098] To resolve the aforementioned problem, the secondary battery (3) may include an insulating member. The insulating member will be described below. FIG. 3 is a cross-sectional view according to II of FIG. 2, and may occupy at least a portion of the internal space (S) defined by the cap (30) direction surface (10a) of the electrode assembly (10), the inner surface (30a) of the cap (30) facing the electrode assembly (10), and the inner surface (20a) of the outer film (20).

[0099] The above-mentioned insulating member is characterized by including a resin having a melting point of 130°C to 350°C. By being placed in the internal space (S), the insulating member containing the above-mentioned resin can prevent flames or heat from being ejected toward the cap (30) when flames and / or heat are generated inside the secondary battery (3), thereby preventing the propagation of flames / heat and performing the function of suppressing a rapid rise in temperature. In order to perform this function, it is necessary to apply a resin having a melting point of 130°C to 350°C.

[0100] In addition to the melting point, there are various other properties that can be considered as thermal characteristics of a resin, such as thermal decomposition temperature, thermal deformation temperature, glass transition temperature, thermal conductivity, or coefficient of thermal expansion. While these various properties represent thermal characteristics, among different resins, the fact that one is high does not mean that other properties will always have equally high values.

[0101] When applying a resin that functions to prevent the propagation of flame and / or heat, the results may vary depending on the physical properties selected. In this regard, the present specification provides a secondary battery capable of preventing the propagation of flame and / or heat by applying a resin having a specific range of melting points as an insulating member. The melting point of a resin may refer to the point at which the resin structurally maintains its function. In some cases, a resin with a high thermal decomposition temperature may be advantageous even if it has a low melting point. However, since it may be desirable for an insulating member applied in the aforementioned location to structurally maintain its shape, a resin having a specific range of melting points may be applied.

[0102] Preferably, the melting point may be 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, 190°C or higher, or 200°C or higher, and additionally, a resin having a melting point of 345°C or lower, 340°C or lower, 335°C or lower, or 330°C or lower may be applied.

[0103] In addition, the above resin has a density of 0.80 g / cm³ 3 Up to 2.50 g / cm³ 3 It may be. Since the density within the above range can affect the energy density of the secondary battery, and while the resin may contribute to safety when applied as an insulating material, it does not contribute to the energy output of the secondary battery; therefore, considering the aspect of energy density per unit weight, it is desirable to apply a resin having an appropriate level of density. Accordingly, the density is 0.85 g / cm³ 3 Above, 0.88 g / cm³ 3 Above, 0.90 g / cm³ 3 Above, 0.95 g / cm³ 3 Above, 1.00 g / cm³ 3 Above, 1.05 g / cm³ 3 Above, 1.10 g / cm³ 3 Above, or 1.15 g / cm³ 3 It may be desirable to have the above, and also 2.30 g / cm³ 3 Below, 2.10 g / cm³ 3 Below, 2.00 g / cm³ 3 Below, 1.80 g / cm³ 3 Below, 1.60 g / cm³ 3 Below, 1.50 g / cm³ 3 Less than or equal to 1.40 g / cm³ 3 It may be desirable to be less than or equal to this.

[0104] For example, the resin may include one or more selected from the group consisting of polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene (PP), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), and polytetrafluoroethylene (PTFE). When applying this type of resin, as described above, it has excellent heat resistance and can exhibit excellent performance in preventing the propagation of flames and heat. In addition, it has excellent chemical resistance and can withstand dissolution and breakage even in environments where it is exposed to the electrolyte for a long period of time, thereby having the advantage of ensuring continuous safety during the normal usage period of the secondary battery.

[0105] In addition, the resin may further include one or more selected from the group consisting of inorganic particles, polyurethane foam, polystyrene foam, silicone foam, phenolic foam, and aerogel to improve heat resistance. Including such materials further can have the effect of increasing the melting temperature of the resin, thereby contributing more to slowing down the propagation of heat and / or flame. The inorganic particles may include one or more selected from the group consisting of boehmite (AlOOH), aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), alumina (Al2O3), titania (TiO2), and zirconia (ZrO2). Additionally, the aerogel may be silica aerogel, formaldehyde-based carbon aerogel, polymer-based aerogel, metal or metal oxide aerogel, cellulose-based aerogel, or ceramic aerogel.

[0106]

[0107] As another example, the thermal insulation member may include a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin. A resin may be applied as the thermal insulation member, with a heat-resistant resin specialized for greater heat resistance applied internally, and a coating material with excellent chemical resistance covering the surface of the heat-resistant resin. When the thermal insulation member is formed by separating the heat-resistant resin and the covering coating material in this manner, durability for long-term use under an electrolyte can be secured due to the excellent chemical resistance, and fire-resistant properties that delay the propagation of heat / flame events can also be secured, thereby demonstrating an excellent effect in improving safety.

[0108] In this case, the heat-resistant resin may have a melting point of 200°C to 350°C, and the coating material may have a melting point of 130°C to 200°C. The melting point of the heat-resistant resin may preferably be 205°C or higher, 210°C or higher, 215°C or higher, 220°C or higher, or 225°C or higher, and may also be 345°C or lower, 340°C or lower, 335°C or lower, or 330°C or lower. Furthermore, the melting point of the coating material may preferably be 135°C or higher, 140°C or higher, or 145°C or higher, and may be 190°C or lower, 180°C or lower, or 170°C or lower. By applying a heat-resistant resin and a coating material having melting points within these ranges, a thermal insulation member having long-term durability and fire-resistant properties can be realized.

[0109] In addition, the heat-resistant resin may include, for example, one or more selected from the group consisting of polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), and polytetrafluoroethylene (PTFE), and these heat-resistant resins are materials with excellent heat resistance and chemical resistance, and may be suitable for thermal insulation members for preventing heat and / or flame propagation.

[0110] The coating material may include, for example, polypropylene (PP). The coating material may be a resin with a relatively lower melting point compared to a heat-resistant resin, but may be a material with excellent chemical resistance. For example, it may have excellent resistance to organic solvents, acids, and alkalis, making it easy to ensure durability for long-term use. In addition, if the coating material includes polypropylene, it may be easy to adhere to the inner surface (30a) of the cap (30) or the inner surface (20a) of the outer film (20), making it easy to place an insulating member in the inner space (S).

[0111] Here, polypropylene may include a homopolymer of propylene; a random copolymer or block copolymer of propylene and an alpha-olefin; or modified polypropylene modified or copolymerized with an acid or siloxane, and the acid used for modification may be a compound including derivatives such as maleic acid, itaconic acid, acrylic acid, phosphonic acid, sulfonic acid, fumaric acid, or their anhydrides, and may be modified by using these for post-treatment or as a monomer during copolymerization.

[0112] The above heat-resistant resin and coating material may each independently further include one or more selected from the group consisting of inorganic particles, polyurethane foam, polystyrene foam, silicone foam, phenolic foam, and aerogel. As described above, even if included in the heat-resistant resin and coating material, the same effect of raising the melting point can be observed, so the effect of further enhancing fire-resistant / heat-resistant performance can be expected.

[0113]

[0114] Referring again to FIG. 3, the insulating member may be placed in an internal space (S), and the internal space (S) may be defined by the cap-facing surface (10a) of the electrode assembly (10), the inner surface (30a) of the cap (30) facing the electrode assembly, and the inner surface (20a) of the outer film (20). The insulating member may be placed in at least a part of the internal space (S), and may be placed to be in contact with at least one of the inner surface (20a) of the outer film (20) and the inner surface (30a) facing the electrode assembly of the cap (30). In order for the insulating member to be fixed so as not to move within the internal space (S), it may be preferable to be adhered to one of the surfaces, and the insulating member may be placed to be in contact with either one of the two surfaces or both surfaces.

[0115] Meanwhile, the above-mentioned insulating member may be positioned so as not to come into contact with the cap-direction surface (10a) of the electrode assembly (10). In some cases, the insulating member may be positioned to come into contact with this surface as well, but since the insulating member is not a means to prevent the movement of the electrode assembly (10) inside the outer film (20) but a member for ensuring safety, it may be desirable to design the insulating member so as not to come into contact with this surface in order to avoid interference with the electrode tab as much as possible and to facilitate the manufacturing of the insulating member. However, given that the electrode tab assembly (11) occupies only a portion of the width direction (Y-axis direction in FIG. 2) of the electrode assembly, the insulating member may also be positioned to come into contact with the cap-direction surface (10a) of the electrode assembly in the remaining space excluding the space occupied by the electrode tab assembly (11) extending from the electrode assembly (10).

[0116] As another example, the insulating member may be coated on at least a portion of one or more surfaces selected from the electrode tab assembly, the inner surface of the outer film, and the inner surface of the cap facing the electrode assembly. The surfaces may be entirely wrapped in a double-layer film, or they may be applied using a liquid coating composition. In this case, while space constraints are minimized and it may be advantageous in terms of energy density, it may be difficult to achieve the effect of preventing the propagation or emission of flame / heat. Therefore, the application of such a form needs to be appropriately applied considering the battery specifications and the application location.

[0117]

[0118] Exemplary structure of an insulating member

[0119] Hereinafter, an example is provided of how an insulating member can be arranged in a structure when placed in an internal space (S). FIG. 5 is a frontal perspective view of the first and second insulating members of a secondary battery according to a first embodiment of the present invention. FIG. 6 is a rearal perspective view of the first and second insulating members of a secondary battery according to a first embodiment of the present invention. FIG. 8 is a cross-sectional view taken along line II-II of FIG. 7. FIG. 9 is an enlarged view of section A of FIG. 7.

[0120] The secondary battery (3) according to the first embodiment of the present invention may include an insulating member (50, 60). The insulating member (50, 60) may be configured to minimize the transfer of thermal energy from the electrode assembly (10) to the cap (30). Through this, in abnormal situations, the discharge of gas or flame can be guided toward the sealing portion of the outer film (20), thereby greatly improving the stability of the secondary battery (3).

[0121] Referring to FIGS. 4 to 8, the insulating member (50, 60) of the secondary battery (3) according to the first embodiment of the present invention may include a first insulating member (50). The first insulating member (50) may include a first insulating portion (52). The first insulating portion (52) may extend in the width direction (Y-axis direction) of the electrode assembly (10). The first insulating portion (52) may minimize heat transfer on the upper side (positive direction of the Z-axis) of the electrode tab assembly (11).

[0122] In this embodiment, with reference to FIGS. 5 to 8, the first insulation portion (52) may include a first cover portion-side insulation portion (53). The first cover portion-side insulation portion (53) may be configured to cover an area of ​​the inward surface (32a) of the cover portion (32). The first cover portion-side insulation portion (53) may suppress the transfer of heat from the electrode assembly (10) to the cover portion (32).

[0123] At this time, the area covered by the insulation portion (53) on the first cover side may be the upper area of ​​the inward surface (32a). The upper area of ​​the inward surface (32a) may be located on the upper side (positive direction of the Z-axis) of the electrode tab assembly (11). The upper area of ​​the inward surface (32a) may be located on the upper side (positive direction of the Z-axis) of the terminal (40). The insulation portion (53) on the first cover side may be in contact with the inward surface (32a).

[0124] In this embodiment, the insulation portion (53) on the first cover side may be extended in the width direction (Y-axis direction) of the electrode assembly (10). At this time, the insulation portion (53) on the first cover side may have a length corresponding to the distance between the third and fourth extension portions (37, 38).

[0125] Here, the fact that the length of the insulation portion (53) on the first cover side corresponds to the distance may mean that the length of the insulation portion (53) on the first cover side is equal to the distance or slightly shorter than the distance, so that it can fit snugly between the third and fourth extension portions (37, 38). This configuration may be intended to stably fix the first insulation member (50) by fitting the insulation portion (53) on the first cover side between the third and fourth extension portions (37, 38).

[0126] Meanwhile, in this embodiment, the first insulation portion (52) may include a first extension-side insulation portion (54). The first extension-side insulation portion (54) may be a portion covering the side of the first extension (35). At this time, the side of the first extension (35) may be an inner side facing the second extension (36). The first extension-side insulation portion (54) may suppress the transfer of heat from the electrode assembly (10) to the extension (34).

[0127] In this embodiment, the insulation portion (54) on the first extension side may extend from the insulation portion (53) on the first cover side toward the electrode assembly (10). Alternatively, the insulation portion (54) on the first extension side may extend parallel to the first extension (35) on the side of the first extension (35).

[0128] In this embodiment, the insulation portion (54) on the first extension side may extend in the width direction (Y-axis direction) of the electrode assembly (10). This may be to cover as much of the first extension (35) as possible and to suppress heat transfer. As a result, the bonding structure between the first extension (35) and the outer film (20) can be protected from high temperatures.

[0129] At this time, the insulation portion (54) on the first extension side may have a length corresponding to the distance between the third and fourth extensions (37, 38). As a result, the insulation portion (54) on the first extension side is also inserted between the third and fourth extensions (37, 38), thereby allowing the first insulation member (50) to be stably fixed.

[0130] Meanwhile, referring to FIGS. 5 to 9, the first insulation portion (52) may include a first end-side insulation portion (55). The first end-side insulation portion (55) may be a portion covering the end of the first extension portion (35). The first end-side insulation portion (55) may be provided at the end of the first extension-side insulation portion (54).

[0131] At this time, the first end-side insulation portion (55) may be configured to cover the gap (g) between the inner surface of the exterior film (20) and the outer surface of the first extension portion (35). In other words, the first end-side insulation portion (55) may be configured to block the gap (g). Here, the inner surface of the exterior film (20) and the outer surface of the first extension portion (35) may be surfaces that face each other and are joined.

[0132] Accordingly, heat transfer from the electrode assembly (10) to the gap (g) can be effectively suppressed. In particular, the gap (g) may be provided with an adhesive or resin for joining the outer film (20) and the extension (34). Since such an adhesive or resin is susceptible to high temperatures, the first end-side insulation portion (55) can further improve the stability of the secondary battery (3) by protecting the gap (g).

[0133] In this embodiment, the first end-side insulation portion (55) may extend in the width direction (Y-axis direction) of the electrode assembly (10). At this time, the length of the first end-side insulation portion (55) may correspond to the distance between the third and fourth extension portions (37, 38). Accordingly, the gap (g) between the first extension portion (35) and the outer film (20) can be entirely protected along the width direction (Y-axis direction).

[0134] Meanwhile, in this embodiment, the first end-side insulation portion (55) may have a predetermined length (L) in the direction (X-axis direction) in which the cap (30) and the electrode assembly (10) are spaced apart from each other. In other words, the first end-side insulation portion (55) may be interposed between the upper part of the cap (30) and the upper part of the electrode assembly (10). The cap (30) and the electrode assembly (10) may be spaced apart by the length (L) by the first end-side insulation portion (55).

[0135] At this time, the length (L) may be 1 mm to 15 mm. In this way, the first end-side insulation portion (55) separates the cap (30) from the electrode assembly (10), thereby minimizing the transfer of heat or pressure generated in the electrode assembly (10) to the cap (30).

[0136] Referring again to FIGS. 5 to 8, the first insulating member (50) of the secondary battery (3) according to the first embodiment of the present invention may include a first side portion (56). The first side portion (56) may be configured to cover and protect other extension portions (34) other than the first extension portion (35).

[0137] In this embodiment, the first side portion (56) may be provided on one side in the extension direction (Y-axis direction) of the first insulation portion (52). The first side portion (56) may extend downward (negative direction of the Z-axis) from the end of the first insulation portion (52) toward the second insulation member (60).

[0138] At this time, the first side portion (56) may be configured as a pair and provided on each side of the extension direction of the first insulation portion (52). The pair of first side portions (56) may be arranged opposite each other with the electrode tab assembly (11) in between. The pair of first side portions (56) may be formed symmetrically with respect to the first insulation portion (52). Of course, the first side portions (56) may have different structures or shapes as needed.

[0139] In this embodiment, the first side portion (56) may include a first side portion (57). The first side portion (57) may extend downward (in the negative direction of the Z-axis) from the first insulation portion (52). Alternatively, the first side portion (57) may have a predetermined length in the vertical direction (in the Z-axis direction).

[0140] Accordingly, the sides of the third and fourth extensions (37, 38) can be covered by the first side portion (57). The first side portion (57) can prevent heat from being transferred from the electrode assembly (10) to the third and fourth extensions (37, 38). Here, the side may be an inner surface where the third and fourth extensions (37, 38) face each other. The first side portion (57) can cover the upper region among the inner surfaces of the third and fourth extensions (37, 38).

[0141] At this time, the lower end of the first side portion (57) may come into contact with the second extension member (60). Here, a portion of the second extension member (60) that comes into contact with the lower end of the first side portion (57) may be the second side portion (67) described later. If necessary, a fixing member, such as an adhesive, may be additionally provided between the first side portion (57) and the second side portion (67).

[0142] As a result, the first insulating member (50) can be stably fixed so that it does not shake or vibrate in the vertical direction (Z-axis direction). In addition, the first side part (57) can cover and protect the inner surface of the third and fourth extension parts (37, 38) together with the second side part (67).

[0143] Meanwhile, in this embodiment, the first side portion (56) may include a first side-side insulation portion (59). The first side-side insulation portion (59) may be a portion extending from the first side portion (57) toward the electrode assembly (10). At this time, the first side-side insulation portion (59) may be configured to cover the ends of the third and fourth extension portions (37, 38). The first side-side insulation portion (59) may cover the upper region among the ends of the third and fourth extension portions (37, 38).

[0144] The first side insulation portion (59) can cover the gap between the inner surface of the exterior film (20) and the sides of the third and fourth extension portions (37, 38). That is, the first side insulation portion (59) can block the gap. Here, the sides of the third and fourth extension portions (37, 38) may be outer surfaces facing the inner surface of the exterior film (20). Through this, the first side insulation portion (59) can effectively suppress the direct transmission of heat or pressure through the gap.

[0145] Meanwhile, in this embodiment, the first side insulation portion (59) may be extended in the vertical direction (Z-axis direction) along the first side portion (57). The first side insulation portion (59) may cover the upper section of the gap entirely. As will be described specifically later, the lower section of the gap may be covered by the second side insulation portion (69) of the second insulation member (60). As a result, the gap between the third and fourth extension portions (37, 38) and the exterior film (20) may be covered entirely by the first and second insulation members (50, 60).

[0146] Referring again to FIGS. 4 to 8, the insulating member (50, 60) of the secondary battery (3) according to the first embodiment of the present invention may include a second insulating member (60). The second insulating member (60) may be located on the opposite side of the first insulating member (50) with the electrode tab assembly (11) in between.

[0147] As such, in this embodiment, the insulating members (50, 60) are composed of a plurality of units, and since the plurality of insulating members (50, 60) are arranged around the electrode tab assembly (11), the manufacturing assembly of the secondary battery (3) can be improved.

[0148] In this embodiment, the second insulating member (60) may include a second insulating portion (62). The second insulating portion (62) may extend in the width direction (Y-axis direction) of the electrode assembly (10). The second insulating portion (62) may minimize heat transfer at the lower side (negative direction of the Z-axis) of the electrode tab assembly (11).

[0149] In this embodiment, the second insulation portion (62) may include a second cover portion-side insulation portion (63). The second cover portion-side insulation portion (63) may be configured to cover an area of ​​the inward surface (32a) of the cover portion (32). The second cover portion-side insulation portion (63) may suppress the transfer of heat from the electrode assembly (10) to the cover portion (32).

[0150] At this time, the area covered by the second cover-side insulation portion (63) may be the lower area of ​​the inward surface (32a). The second cover-side insulation portion (63) may be positioned at a predetermined distance downward (in the negative direction of the Z-axis) from the first cover-side insulation portion (53).

[0151] Here, the lower region of the inward surface (32a) may be located on the lower side (negative direction of the Z-axis) of the electrode tab assembly (11). The upper region of the inward surface (32a) may be located on the lower side (negative direction of the Z-axis) of the terminal (40). As a result, the electrode tab assembly (11) can penetrate between the first and second cover-side insulation portions (53, 63) and be coupled to the terminal (40). Meanwhile, the second cover-side insulation portion (63) may be in contact with the inward surface (32a).

[0152] In this embodiment, the second cover-side insulation portion (63) may extend in the width direction (Y-axis direction) of the electrode assembly (10). At this time, the second cover-side insulation portion (63) may have a length corresponding to the distance between the third and fourth extension portions (37, 38). This may be so that the second insulation member (60) is stably fixed by fitting the second cover-side insulation portion (63) between the third and fourth extension portions (37, 38).

[0153] Meanwhile, in this embodiment, the second insulation part (62) may include a second extension-side insulation part (64). The second extension-side insulation part (64) may be a part that covers the side of the second extension part (36). At this time, the side of the second extension part (36) may be an inner side facing the first extension part (35). The second extension-side insulation part (64) can suppress the transfer of heat from the electrode assembly (10) to the extension part (34).

[0154] In this embodiment, the second extension-side insulation portion (64) may extend from the second cover-side insulation portion (63) toward the electrode assembly (10). Alternatively, the second extension-side insulation portion (64) may extend parallel to the second extension portion (36) on the side of the second extension portion (36).

[0155] In this embodiment, the insulating portion (64) on the second extension side may extend in the width direction (Y-axis direction) of the electrode assembly (10). This may be to cover as much of the second extension (36) as possible and to suppress heat transfer. As a result, the bonding structure between the second extension (36) and the outer film (20) can be protected from high temperatures.

[0156] At this time, the insulation portion (64) on the second extension side may have a length corresponding to the distance between the third and fourth extensions (37, 38). As a result, the insulation portion (64) on the second extension side is also inserted between the third and fourth extensions (37, 38), thereby allowing the second insulation member (60) to be stably fixed.

[0157] Meanwhile, referring to FIGS. 5 to 9, the second insulation portion (62) may include a second end-side insulation portion (65). The second end-side insulation portion (65) may be a portion covering the end of the second extension portion (36). The second end-side insulation portion (65) may be provided at the end of the second extension-side insulation portion (64).

[0158] At this time, the second end-side insulation portion (65) may be configured to cover the gap between the inner surface of the exterior film (20) and the outer surface of the second extension portion (36). In other words, the second end-side insulation portion (65) may be configured to block the gap. Here, the inner surface of the exterior film (20) and the outer surface of the second extension portion (36) may be surfaces that face each other and are joined. Accordingly, heat transfer from the electrode assembly (10) to the gap can be effectively suppressed.

[0159] In this embodiment, the second end-side insulation portion (65) may extend in the width direction (Y-axis direction) of the electrode assembly (10). At this time, the length of the second end-side insulation portion (65) may correspond to the distance between the third and fourth extension portions (37, 38). Accordingly, the gap between the second extension portion (36) and the outer film (20) can be entirely protected along the width direction (Y-axis direction).

[0160] Meanwhile, in this embodiment, the second end-side insulation portion (65) may have a predetermined length in the direction (X-axis direction) in which the cap (30) and the electrode assembly (10) are spaced apart from each other. In other words, the second end-side insulation portion (65) may be interposed between the lower part of the cap (30) and the lower part of the electrode assembly (10). The cap (30) and the electrode assembly (10) may be spaced apart by the length above by the first and second end-side insulation portions (55, 65).

[0161] At this time, the length may be 1 mm to 15 mm. In this way, the second end-side insulation portion (65) separates the cap (30) from the electrode assembly (10), thereby minimizing the transfer of heat or pressure generated in the electrode assembly (10) to the cap (30).

[0162] Referring again to FIGS. 5 to 8, the second insulating member (60) of the secondary battery (3) according to the first embodiment of the present invention may include a second side portion (66). The second side portion (66) may be configured to cover and protect other extension portions (34) other than the second extension portion (36).

[0163] In this embodiment, the second side portion (66) may be provided on one side in the extension direction (Y-axis direction) of the second insulation portion (62). The second side portion (66) may extend upward (positive direction of the Z-axis) from the end of the second insulation portion (62) toward the first insulation member (50).

[0164] At this time, the second side portion (66) may be configured as a pair and provided on each side of the extension direction of the second insulation portion (62). The pair of second side portions (66) may be positioned opposite each other with the electrode tab assembly (11) in between. The pair of second side portions (66) may be formed symmetrically with respect to the second insulation portion (62). Of course, if necessary, the pair of second side portions (66) may have different structures or shapes.

[0165] In this embodiment, the second side portion (66) may include a second side portion (67). The second side portion (67) may extend downward (in the negative direction of the Z-axis) from the second insulation portion (62). Alternatively, the second side portion (67) may have a predetermined length in the vertical direction (in the Z-axis direction).

[0166] Accordingly, the sides of the third and fourth extensions (37, 38) can be covered by the second side portion (67). The second side portion (67) can prevent heat from being transferred from the electrode assembly (10) to the third and fourth extensions (37, 38). Here, the side may be an inner surface where the third and fourth extensions (37, 38) face each other. The second side portion (67) can cover the lower region among the inner surfaces of the third and fourth extensions (37, 38).

[0167] At this time, the upper portion of the second side portion (67) may come into contact with the first insulating member (50). Here, a portion of the first insulating member (50) that comes into contact with the upper portion of the second side portion (67) may be the aforementioned first side portion (57). As a result, the second insulating member (60) can be stably fixed so that it does not shake or vibrate in the vertical direction (Z-axis direction).

[0168] Meanwhile, in this embodiment, the second side portion (66) may include a second side-side insulation portion (69). The second side-side insulation portion (69) may be a portion extending from the second side portion (67) toward the electrode assembly (10). At this time, the second side-side insulation portion (69) may be configured to cover the ends of the third and fourth extension portions (37, 38). The second side-side insulation portion (69) may cover the lower region among the ends of the third and fourth extension portions (37, 38).

[0169] The second side insulation portion (69) can cover the gap between the inner surface of the exterior film (20) and the sides of the third and fourth extension portions (37, 38). That is, the second side insulation portion (69) can block the gap. Here, the sides of the third and fourth extension portions (37, 38) may be outer surfaces facing the inner surface of the exterior film (20). Through this, the second side insulation portion (69) can effectively suppress the direct transmission of heat or pressure through the gap.

[0170] Meanwhile, in this embodiment, the second side insulation portion (69) may extend in the vertical direction (Z-axis direction) along the second side portion (67). The second side insulation portion (69) may cover the entire lower section of the gap. The first and second side insulation portions (59, 69) may come into contact with each other. Therefore, the gap may be entirely covered by the first and second side insulation portions (59, 69).

[0171] As previously explained, in the secondary battery (3) according to the first embodiment of the present invention, an insulating member (50, 60) is provided between the cap (30) and the electrode assembly (10) so that pressure or heat can be suppressed from being transferred to the cap (30). Through this, the direction of discharge of gas or flame can be guided toward the outer film (20), thereby improving the stability of the secondary battery (3).

[0172] In particular, in this embodiment, the insulating members (50, 60) have an insulating portion (53, 63) on the cover side, an insulating portion (54, 64) on the extension side, and an insulating portion (55, 65) on the end side, which respectively cover the gap between the cover portion (32), the extension portion (34) of the cap (30), and the outer film (20) and the extension portion (34), so the transfer of heat or pressure can be suppressed more effectively. In addition, in this embodiment, the insulating members (50, 60) are provided in multiple numbers and arranged around the electrode tab assembly (11), so the assemblyability of the secondary battery (3) can be improved during manufacturing.

[0173] Hereinafter, a secondary battery according to another embodiment of the present invention is described. At this time, the description focuses on the differences from the secondary battery according to the first embodiment of the present invention described above.

[0174] FIG. 10 is a cross-sectional view of a secondary battery according to a second embodiment of the present invention, cut according to II of FIG. 2. FIG. 11 is a cross-sectional view of a secondary battery according to a third embodiment of the present invention, cut according to II of FIG. 2. FIG. 12 is an exploded perspective view of the first and second insulating members of a secondary battery according to a fourth embodiment of the present invention. At this time, the first and second insulating members are rotated so that the joint portion is clearly visible. FIG. 13 is a cross-sectional view of a secondary battery according to a fifth embodiment of the present invention, cut according to II of FIG. 2. FIG. 14 is a cross-sectional view of a secondary battery according to a sixth embodiment of the present invention, cut according to II of FIG. 2.

[0175] FIG. 10 discloses a secondary battery according to a second embodiment of the present invention. Referring to FIG. 10, in the secondary battery (103) according to the second embodiment of the present invention, the corner portions (153a, 163a) of the first and second cover-side insulation portions (53, 53) may have a round or chamfered shape. At this time, the corner portions (153a, 163a) may be corner portions facing the electrode tab assembly (11).

[0176] In this embodiment, the corner portions (154a, 164a) of the insulation portions (54, 64) on the first and second extension sides may have a round or chamfered shape. At this time, the corner portions (154a, 164a) may be corner portions facing the electrode tab assembly (11). This configuration may be intended to prevent the electrode tab assembly (11) from being damaged by the insulation member (150, 160).

[0177] FIG. 11 discloses a secondary battery according to a third embodiment of the present invention. Referring to FIG. 11, the first insulating portion (253) of the secondary battery (203) according to the third embodiment of the present invention may have a convex shape toward the electrode tab assembly (11). Through this, damage to the electrode tab assembly (11) by the first insulating portion (253) can be prevented.

[0178] At this time, the first insulation portion (253) may have a shape in which the thickness increases from the central part of the cover portion (32) toward the first extension portion (35). At this time, the thickness may be the thickness measured in the extension direction (X-axis direction) of the electrode assembly (10). At least a portion of the first insulation portion (253) may have a thickness greater than the length of the first extension portion (35). The at least portion of the first insulation portion (253) may have a thickness thinner than the gap between the electrode assembly (10) and the cover portion (32).

[0179] Accordingly, the upper region between the cap (30) and the electrode assembly (10) can be mostly occupied by the first insulating part (253). In other words, the first insulating part (253) can fill most of the upper region. As a result, the transfer of heat or pressure from the electrode assembly (10) to the cover part (32) and the first extension part (35) can be further suppressed.

[0180] Meanwhile, the second insulation portion (263) of the secondary battery (203) according to the third embodiment of the present invention may have a convex shape toward the electrode tab assembly (11). Through this, damage to the electrode tab assembly (11) caused by the second insulation portion (263) can be prevented.

[0181] At this time, the second insulation portion (263) may have a shape in which the thickness increases from the central part of the cover portion (32) toward the second extension portion (36). At this time, the thickness may be the thickness measured in the extension direction (X-axis direction) of the electrode assembly (10). At least a portion of the second insulation portion (263) may have a thickness greater than the length of the second extension portion (36). The at least portion of the second insulation portion (263) may have a thickness thinner than the gap between the electrode assembly (10) and the cover portion (32).

[0182] Accordingly, the lower region between the cap (30) and the electrode assembly (10) can be mostly occupied by the second insulating part (263). In other words, the second insulating part (263) can fill most of the lower region. As a result, the transfer of heat or pressure from the electrode assembly (10) to the cover part (32) and the second extension part (36) can be further suppressed.

[0183] FIG. 12 discloses an insulating member of a secondary battery according to a fourth embodiment of the present invention. Referring to FIG. 12, in the secondary battery according to the fourth embodiment of the present invention, the assemblability of the insulating member (350, 360) can be further improved.

[0184] More specifically, in this embodiment, the first side portion (356) of the first insulating member (350) may include a first connecting portion (358). The first connecting portion (358) may be a portion that is connected to the second insulating member (360). The first connecting portion (358) may be provided at the end of the first side portion. The first connecting portion (358) may be formed of a projection protruding toward the second insulating member (360).

[0185] In this embodiment, the second side portion (366) of the second insulating member (360) may include a second connecting portion (368). The second connecting portion (368) may be a portion that is connected to the first connecting portion (358) in a shape-matched manner. The second connecting portion (368) may be provided at the end of the second side portion. The second connecting portion (368) may be formed as a hole into which the first connecting portion (358) can enter.

[0186] Accordingly, not only can the assembly and coupling between the first and second insulating members (350, 360) be improved, but the structural stability of the secondary battery can also be improved. Meanwhile, in this embodiment, the coupling portion (358, 368) of the insulating member (350, 360) is described as being composed of protrusions and holes. However, the structure or shape of the coupling portion (358, 368) of the insulating member (350, 360) is not particularly limited as long as the coupling of the two components can be achieved.

[0187] FIG. 13 discloses a secondary battery according to a fifth embodiment of the present invention. Referring to FIG. 13, the secondary battery (403) according to the fifth embodiment of the present invention may further include a coupling portion (451, 461). In this embodiment, the coupling portion (451, 461) may be configured to combine an outer film (20) and an insulating member (450, 460). As a result, the structural stability of the secondary battery (403) may be further improved.

[0188] In this embodiment, one region of the outer surface of the first insulating member (450) may face the inner surface of the outer film (20). More specifically, the outer surface of the first end-side insulating portion (55) and the first side-side insulating portion of the first insulating member (450) may face the inner wall of the outer film (20). Here, the outer surface may be a surface facing the outer side of the secondary battery (403) along a direction perpendicular to the longitudinal direction (X-axis direction) of the electrode assembly (10) (Y-axis or Z-axis direction).

[0189] A first bonding portion (451) may be provided between the one region of the first insulating member (450) and the inner surface of the exterior film (20). The first bonding portion (451) may be provided as a bonding layer that bonds the one region and the exterior film (20). The first bonding portion (451) may be composed of an adhesive applied to the one region. Alternatively, the first bonding portion (451) may be formed as the first insulating member (450) and the exterior film (20) are sealed by heat or pressure. To this end, a polypropylene (PP) layer may be provided on the one region of the first insulating member (450), but is not limited thereto, and as described above, when the insulating member (450, 460) is applied in a form including a heat-resistant resin and a coating material, the bonding portion (451, 461) may be a coating material.

[0190] In this embodiment, one region of the outer surface of the second insulation member (460) may face the inner surface of the outer film (20). More specifically, the outer surface of the second end-side insulation portion (65) and the second side-side insulation portion of the second insulation member (460) may face the inner wall of the outer film (20). Here, the outer surface may be a surface facing the outer side of the secondary battery (403) along a direction perpendicular to the longitudinal direction (X-axis direction) of the electrode assembly (10) (Y-axis or Z-axis direction).

[0191] A second bonding portion (461) may be provided between the one region of the second insulating member (460) and the inner surface of the exterior film (20). The second bonding portion (461) may be provided as a bonding layer that bonds the one region and the exterior film (20). The second bonding portion (461) may be composed of an adhesive applied to the one region. Alternatively, the second bonding portion (461) may be formed as the second insulating member (460) and the exterior film (20) are compressed by heat or pressure. To this end, a polypropylene (PP) layer may be provided on the one region of the second insulating member (460), but is not limited thereto.

[0192] FIG. 14 discloses a secondary battery according to a sixth embodiment of the present invention. Referring to FIG. 14, a coating layer (550a) may be provided on a first insulating member (550) of a secondary battery (503) according to a sixth embodiment of the present invention. The coating layer (550a) may be provided on the outer surface of the first insulating member (550).

[0193] In this embodiment, the coating layer (550a) may be configured to cover the entire outer surface of the first insulating member (550). Alternatively, the coating layer (550a) may be provided only in the area of ​​the outer surface of the first insulating member (550) that is exposed to the space where the electrode assembly (10) is accommodated, and may not be provided in the area that is not exposed to the space and is covered by the cap (30) or the outer film (20).

[0194] In this embodiment, the coating layer (550a) may be made of a material having chemical resistance. For example, the chemical resistance may include resistance to an electrolyte. As a result, the material of the first insulating member (550) only needs to satisfy thermal insulation and may not separately have chemical resistance. Consequently, a material having higher heat resistance or thermal insulation can be used in the first insulating member (550) without concerns regarding chemical resistance.

[0195] As an example, the coating layer (550a) may include at least one of a polyolefin resin and Teflon. However, the material of the coating layer (550a) is not limited to that described above. Meanwhile, in this embodiment, a coating layer (560a) may also be provided on the second insulating member (560). The coating layer (560a) provided on the outer surface of the second insulating member (560) may be configured in the same way as the coating layer (560a) of the first insulating member (550) described above. Additionally, as described above, when the insulating members (550, 560) are applied in a form including a heat-resistant resin and a coating material, the coating layer (550a, 560a) may be a coating material.

[0196] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations 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.

[0197]

[0198] Examples

[0199] Example 1

[0200] An exterior film having a polyethylene terephthalate / nylon / aluminum alloy thin film / polypropylene film structure was prepared by laminating a polyethylene terephthalate (PET) film with a width of 266 mm, a length of 50 m, and a thickness of 12 μm and a nylon film with a width of 266 mm, a length of 50 m, and a thickness of 25 μm on one side of an aluminum alloy thin film with a width of 266 mm, a length of 50 m, and a thickness of 80 μm on the other side, and laminating a polypropylene film with a width of 266 mm, a length of 50 m, and a thickness of 80 μm on the other side. Here, the polyethylene terephthalate film and the nylon film are the substrate layer, the aluminum alloy thin film is the gas barrier layer, and the polypropylene film is the sealant layer.

[0201] Next, the cap was prepared by insert injection molding using an aluminum metal plate and polypropylene resin.

[0202] An electrode assembly was prepared by simulating the assembly of a negative electrode, a positive electrode, and a porous polyethylene separator using a stacking method, and after wrapping it with the outer film, a secondary battery of the form shown in FIG. 2 was manufactured using a cap, wherein PP with a melting point of 140°C was placed as a sheet-type insulating member (thickness 10 mm) in the region corresponding to S in FIG. 3, which is the area between the inner side of the cap and the electrode assembly. At this time, the sealing of the outer film and the cap was performed for 5 seconds under conditions of 240°C and 0.6 MPa.

[0203]

[0204] Examples 2 and 3

[0205] A secondary battery was manufactured in the same manner as Example 1 above, except for the type of insulating material listed in Table 1.

[0206]

[0207] Experimental Example 1. Evaluation of Vent Direction

[0208] A heater (120 mm x 60 mm) was placed on the secondary battery manufactured above, a thermocouple was attached between the heater and the cell, and the heater was fixed with PI tape. Then, a Superwool insulation material (10T, 300 mm x 100 mm) was attached to the outer surface of the cell, and an aluminum plate (10T, 600 mm x 105 mm) was attached to the outer surface, and the components were fastened together as a laminate by applying pressure of 30 kPa.

[0209] The heater was operated at a heating rate of 5 ℃ / min to induce thermal runaway in cell A, and the direction of the flame vent during thermal runaway in each cell was checked.

[0210]

[0211] Resin Type Resin Melting Point (°C) Vent Direction Example 1 PP140 Side Section Example 2 PP160 Side Section Example 3 PTFE325 Side Section

[0212] Referring to Table 1 above, it can be confirmed that by applying a resin with a melting point of 130°C to 350°C as an insulating material, the vent direction can be controlled to the side.

[0213]

[0214] [Explanation of the symbol]

[0215] 1: Battery box 2: Packaging

[0216] 3, 103, 203: Secondary battery

[0217] 10: Electrode assembly 10a: Cap-facing surface of the electrode assembly

[0218] 11: Electrode tab assembly

[0219] 20: Exterior film 20a: Inner surface of the exterior film

[0220] 30: Cap 30a: Inner surface of the cap

[0221] 32: Cover part 34: Extension part

[0222] 40, 240: Terminal

[0223] 50, 150, 250, 350, 450, 550: First insulation member

[0224] 52, 252, 352: 1st insulation section

[0225] 56, 356: 1st side section

[0226] 60, 160, 260, 360, 460, 560: Second insulation member

[0227] 62, 262, 362: First insulation section

[0228] 66, 366: Second side

[0229] 460: Joint

[0230] 550a, 560a: Coating layer

Claims

1. Electrode assembly extended in one direction; A cap including a cover portion covering one side in the extension direction of the electrode assembly; An outer film wrapping the perimeter side of the electrode assembly; and It includes an insulating member that occupies at least a portion of the internal space defined by the cap-direction surface of the electrode assembly, the inner surface of the cap facing the electrode assembly, and the inner surface of the outer film, and The above-mentioned insulating member comprises a resin having a melting point of 130°C to 350°C, and is a secondary battery.

2. In Paragraph 1, The above resin has a density of 0.80 g / cm³ 3 Up to 2.50 g / cm³ 3 Phosphorus, secondary battery.

3. In Paragraph 1, The above resin is a secondary battery having a melting point of 150°C to 350°C.

4. In Paragraph 1, The above resin has a density of 1.20 g / cm³ 3 Up to 3.00 g / cm³ 3 Phosphorus, secondary battery.

5. In Paragraph 1, The above resin comprises one or more selected from the group consisting of polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene (PP), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), and polytetrafluoroethylene (PTFE), forming a secondary battery.

6. In Paragraph 1, The above-mentioned insulating member comprises a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin, a secondary battery.

7. In Paragraph 1, The above-mentioned insulating member comprises a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin, and The heat-resistant resin comprises one or more selected from the group consisting of polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), and polytetrafluoroethylene (PTFE). The above coating material is a secondary battery comprising polypropylene (PP), 8. In Paragraph 1, The above-mentioned insulating member comprises a heat-resistant resin and a coating material disposed on the surface of the heat-resistant resin, and The above heat-resistant resin has a melting point of 200°C to 350°C, and The above coating material is a secondary battery having a melting point of 130°C to 200°C.

9. In Paragraph 1, The above resin further comprises one or more selected from the group consisting of inorganic particles, polyurethane foam, polystyrene foam, silicone foam, phenolic foam, and aerogel, forming a secondary battery.

10. In Paragraph 1, A secondary battery, wherein the insulating member is disposed in at least a part of the internal space, but is disposed not to come into contact with the cap-direction surface of the electrode assembly.

11. In Paragraph 1, A secondary battery, wherein the above-described insulating member is disposed in at least a part of the internal space and is disposed to be in contact with at least one of the inner surface of the outer film and the inner surface facing the electrode assembly of the cap.

12. In Paragraph 1, The above secondary battery further includes an electrode tab assembly extending from the electrode assembly toward the cap side, and A secondary battery in which the above-mentioned insulating member is divided and arranged into a first insulating member and a second insulating member with the above-mentioned electrode tab assembly in between.

13. In Paragraph 1, The above secondary battery further includes an electrode tab assembly extending from the electrode assembly toward the cap side, and A secondary battery, wherein the above-described insulating member is coated on at least a portion of one or more surfaces selected from the electrode tab assembly, the inner surface of the outer film, and the inner surface of the cap facing the electrode assembly.

14. In Paragraph 1, A secondary battery in which the first insulating member and the second insulating member have a shape symmetrical with respect to the electrode tab assembly.

15. Secondary battery; and It includes a packaging that accommodates the above secondary battery, and The above secondary battery is, Electrode assembly extended in one direction; A cap including a cover portion covering one side in the extension direction of the electrode assembly; An outer film wrapping the perimeter side of the electrode assembly; and It includes an insulating member that occupies at least a portion of the internal space defined by the cap-direction surface of the electrode assembly, the inner surface of the cap facing the electrode assembly, and the inner surface of the outer film, and The above-mentioned insulating member comprises a resin having a melting point of 130°C to 350°C, and is a battery box.

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